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MSFC-SPEC-3679
National Aeronautics and REVISION A
Space Administration EFFECTIVE DATE: October 22, 2018
George C. Marshall Space Flight Center
Marshall Space Flight Center, Alabama 35812
EM30
MSFC TECHNICAL STANDARD
PROCESS SPECIFICATION -
WELDING AEROSPACE
HARDWARE
Approved for Public Release; Distribution is Unlimited
MEASUREMENT SYSTEM
ENGLISH/METRIC (SI)
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 2 of 92
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DOCUMENT HISTORY LOG
Status (Baseline/
Revision/
Cancelled)
Document
Revision
Effective Date
Description
Baseline
-
10/11/2012
Baseline Release; document authorized through
MPDMS. [Baselined by Upper Stage Element
Control Board Directive CE4-01-0239, (PCN
CE001107, CR CLV-US-0481).]
Revision
A
10/22/2018
Added section 1.3 – Units of Measurement. Moved
sections 1.4 – Safety and 1.5 – Specific Process
Weld Requirements to section 3.0 – Requirements.
Added CGA specifications and removed cancelled
gas specifications from section 2.0 – Applicable
Standards and Documents. Moved Acronyms and
Definitions from section 3.0 to Appendix I –
Acronyms and Definitions. Removed section 5.1.5
– Weld Equipment Requalification and added
section 5.1.10 – Weld Equipment Modification.
Clarified section 7.3.2 – Weld Testing
Methodology. Moved section 9.5.2.b – Equipment
Fluctuations to Section 5.1 – Welding Equipment.
Reformatted Tables in Appendix A.
Clarified intent of Confidence Weld Requirements
and moved sections within 7.3 for a logical
approach.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 3 of 92
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TABLE OF CONTENTS
PARAGRAPH PAGE
SCOPE ................................................................................................................................... 8
Purpose ................................................................................................................................ 8
Applicability ....................................................................................................................... 8
Units of Measurement ......................................................................................................... 9
Tailoring .............................................................................................................................. 9
APPLICABLE DOCUMENTS .......................................................................................... 10
Applicable Standards and Documents .............................................................................. 10
Reference Documents ....................................................................................................... 12
Order of Precedence .......................................................................................................... 12
REQUIREMENTS .............................................................................................................. 13
Safety ................................................................................................................................ 13
Specific Process Weld Requirements ............................................................................... 13
JOINT CLASSES................................................................................................................ 14
Inspection Criteria ............................................................................................................. 14
Joint Classifications .......................................................................................................... 14
EQUIPMENT ...................................................................................................................... 15
Welding Equipment .......................................................................................................... 15
Tooling and Fixtures ......................................................................................................... 16
Electron Beam Welding .................................................................................................... 17
MATERIALS ...................................................................................................................... 18
Base Metals ....................................................................................................................... 18
Filler Metals ...................................................................................................................... 18
Shielding Gas .................................................................................................................... 18
Tungsten Electrodes .......................................................................................................... 19
FSW Pin Tools .................................................................................................................. 19
Anvils and Plug Weld Backing Material .......................................................................... 19
Friction Plugs .................................................................................................................... 19
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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WELDER PERFORMANCE AND WELD PROCEDURE QUALIFICATION ......... 20
Welder Performance Qualification ................................................................................... 20
Weld Procedure Specification........................................................................................... 20
Procedure Qualification Records ...................................................................................... 22
Records ............................................................................................................................. 24
PREWELD OPERATIONS ............................................................................................... 25
Weld Joint Design ............................................................................................................. 25
Preweld Cleaning .............................................................................................................. 25
Preweld Joint Fit-up .......................................................................................................... 26
Weld Start and Run-Off Tabs ........................................................................................... 27
Laser and Electron Beam-to-Joint Alignment .................................................................. 27
PRODUCTION WELDING .............................................................................................. 28
Equipment Operational Readiness Check ......................................................................... 28
Temperature Control. ........................................................................................................ 28
Tack Welding .................................................................................................................... 28
Welding Techniques ......................................................................................................... 28
Welding Procedure............................................................................................................ 29
POSTWELD OPERATION ............................................................................................... 30
The Weldment ................................................................................................................... 30
General Workmanship Requirements ............................................................................... 30
Dimensional Requirements ............................................................................................... 30
Weldment Straightening ................................................................................................... 33
Postweld Heat Treatment Requirements ........................................................................... 34
Weldment Quality Requirements ...................................................................................... 34
Repair Welding ................................................................................................................. 34
Material Review Board ..................................................................................................... 35
VERIFICATION................................................................................................................. 36
General .............................................................................................................................. 36
Postweld Inspection .......................................................................................................... 36
Records ............................................................................................................................. 37
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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LIST OF APPENDICES
Appendix Page
Appendix A Procedure Qualification Weld Strength Requirements ................................................ 39
Appendix B Weld Joint Dimensional Requirements ........................................................................ 44
Appendix C Weld Nugget Dimensional Requirements .................................................................... 46
Appendix D Weld Quality Requirements ......................................................................................... 65
Appendix E Weld Procedure Specification Information .................................................................. 73
Appendix F Recommended Weld Filler Metals ............................................................................... 75
Appendix G Preweld and Postweld Cleaning Methods .................................................................... 82
Appendix H Reference Documents .................................................................................................. 83
Appendix I Acronyms and Definitions ............................................................................................. 85
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 6 of 92
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LIST OF TABLES
Table Page
Table I. Minimum Inspection Requirements .................................................................................... 14
Table II. WPS Allowable Qualified Thickness Range ..................................................................... 20
Table III. GTAW Process Butt Weld Ultimate Tensile Strength Requirements .............................. 40
Table IV. VPPA Process Butt Weld Ultimate Tensile Strength Requirements ................................ 41
Table V. FSW Process Butt Weld Ultimate Tensile Strength Requirements ................................... 41
Table VI. Close-out FPW in FSW Process Ultimate Tensile Strength Requirements ..................... 42
Table VII. Fusion Butt Weld Ultimate Tensile Strength Requirements for Superalloys ................. 43
Table VIII. Fusion Butt Weld Ultimate Tensile Strength Requirements for Titanium Alloys ......... 43
Table IX. Fusion Butt Weld Ultimate Tensile Strength Requirements for Stainless Steel Alloys ... 43
Table X. Preweld Joint Fit-up Requirements .................................................................................... 44
Table XI. Postweld Joint Fit-up Requirements ................................................................................. 45
Table XII. Dimensional Requirements for Butt Welds – Fusion
1
.................................................... 46
Table XIII. Dimensional Characteristics of Aluminum Alloy Butt Welds ...................................... 50
Table XIV. Dimensional Requirements ............................................................................................ 52
Table XV. Weld Surface and Volumetric Acceptance Criteria – Aluminum Alloys ....................... 65
Table XVI. Surface and Volumetric Acceptance Criteria – Steels, Heat Resistant Alloys .............. 71
Table XVII. Weld Surface and Volumetric Acceptance Criteria – Titanium Alloys ....................... 72
Table XVIII. Recommended Parameters to be Recorded in a WPS ................................................. 73
Table XIX. Filler Alloys Recommended for Aluminum Alloys and Combinations ........................ 75
Table XX. Filler Alloys Recommended for Carbon and Low Alloy Steels and Combinations ....... 76
Table XXI. Filler Alloys Recommended for Stainless Steels and Combinations ............................ 77
Table XXII. Filler Alloys Recommended for Nickel- and Cobalt-Base Alloys and Combinations . 79
Table XXIII. Filler Alloys Recommended for Copper Alloys and Combinations ........................... 81
Table XXIV. Filler Alloys Recommended for Titanium Alloys and Combinations ........................ 81
Table XXV. Acceptable Preweld and Postweld Cleaning Methods ................................................. 82
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 7 of 92
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LIST OF FIGURES
Figure Page
Figure 1. Welding Techniques .......................................................................................................... 29
Figure 2. Mismatch and Peaking ...................................................................................................... 31
Figure 3. Fillet Weld Throats ............................................................................................................ 32
Figure 4. Fillet Welds ....................................................................................................................... 33
Figure 5. Aluminum Fusion Butt Weld ............................................................................................ 46
Figure 6. EBW Butt Weld ................................................................................................................. 47
Figure 7. EBW Max Weld Crown and Root Widths for Penetration Depths (D) ≤ 1.6 in [41 mm] 48
Figure 8. Min EBW Root Width for Penetration Depths (D) ≤ 0.2 in [5 mm] ................................. 49
Figure 9. Min EBW Root Width for Penetration Depths (D) of 0.2-1.6 in [5-41 mm] .................... 50
Figure 10. C-FSW Zone .................................................................................................................... 51
Figure 11. SR-FSW Zone ................................................................................................................. 51
Figure 12. Titanium Full-Penetration Joint Welds ........................................................................... 53
Figure 13. Titanium Butt Joint Maximum Allowable Weld Width (W) versus Thickness (t) ......... 54
Figure 14. Titanium Fillet Joint Maximum Allowable Weld Width versus Thickness .................... 55
Figure 15. Titanium Maximum Fillet Weld Size L
MIN
= thickness of the thinnest member ............ 56
Figure 16. Titanium Fillet Weld Dimensions for Acute Angle and Drop Through ......................... 56
Figure 17. Weld Size Requirements for Butt Welds......................................................................... 57
Figure 18. Class A Butt Weld Fusion Zone Weld Size Limits ......................................................... 58
Figure 19. Class B Butt Weld Fusion Zone Weld Size Limits ......................................................... 59
Figure 20. Class C Butt Weld Fusion Zone Weld Size Limits ......................................................... 60
Figure 21. Weld Size Requirements for T and Corner Welds .......................................................... 61
Figure 22. Class A, T and Corner Weld Fusion Zone Weld Size Limits ......................................... 62
Figure 23. Class B, T and Corner Weld Fusion Zone Weld Size Limits .......................................... 63
Figure 24. Class C, T and Corner Weld Fusion Zone Weld Size Limits .......................................... 64
Figure 25. External Discontinuities for Aluminum Alloys ............................................................... 69
Figure 26. Internal Defects for Aluminum Alloys ............................................................................ 70
Figure 27. EBW Porosity Acceptance Criteria for Steels, Heat Resistant ........................................ 72
Figure 28. Conventional-Friction Stir Welding Process ................................................................... 90
Figure 29. Self Reacting-Friction Stir Welding Process ................................................................... 90
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 8 of 92
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SCOPE
This process specification establishes uniform requirements for the design, fabrication, and
inspection of welds in flight hardware. This process specification may also be used for special test
articles and ground support equipment. This specification combines the lessons learned from
extensive Agency-wide welding engineering experiences and combines the requirements of project,
Center, other government, and industry documents used for the manufacture of historic spaceflight
hardware such as Saturn, the Space Shuttle, and the International Space Station.
When this process specification is specified on contract documents, the contractor may submit an
alternative, corporate, detailed weld process specification that meets the intent of this specification.
Industry, government, and company specifications may be used for welding hardware in lieu of this
specification if approved by the responsible National Aeronautics and Space Administration
(NASA) Technical Authority. The content of this process specification meets the intent of NASA-
STD-5006A.
Purpose
The purpose of this process specification is to establish the minimum process control requirements
for the design, fabrication (including the qualification of welders, welding operators, and welding
procedure specifications), and quality assurance of manual, semi-automatic, mechanized, and
automatic welds in flight hardware, special test articles and ground support equipment used by or
for Marshall Space Flight Center (MSFC). This process specification will be used for flight
hardware. This process specification may be used on special test articles and ground support
equipment.
Applicability
This process specification is approved for use by MSFC and may be cited in contract, program, and
other documents as a technical requirement. This process specification may also apply to
contractors and subcontractors to the extent specified or referenced in their contracts.
This standard applies the following convention: all mandatory actions (i.e., requirements) are
denoted by statements containing the term “shall”, the term “will” denotes an expected outcome,
and the terms “may” or “should” denote explanatory or guidance text indicated in italics beginning
in Section 4.0.
Applicable Processes
This process specification is applicable to fusion arc, solid-state, resistance and high-energy
density weld processes for joining metallic materials. These include, but are not limited to, the
following and the pulsed derivate:
(1) FCAW - Flux-Cored Arc Welding
(2) GMAW - Gas Metal Arc Welding
(3) GTAW - Gas Tungsten Arc Welding
(4) PAW - Plasma Arc Welding
(5) SMAW - Shielded Metal Arc Welding
(6) SAW - Submerged Arc Welding
(7) VPPA - Variable Polarity Plasma Arc
(8) Direct Drive Friction Welding
(9) Inertia Friction Welding
(10) FRW - Friction Welding
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 9 of 92
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(11) FSW - Friction Stir Welding
(12) FPW - Friction Plug Welding
(13) EBW - Electron Beam Welding
(14) LBW - Laser Beam Welding
Applicable Materials
This process specification covers all metallic materials used in the manufacture of flight hardware.
Units of Measurement
This standard makes use of both U.S. Customary Units (US) and the International System of Units (SI).
The latter are shown within brackets ([ ]) or in appropriate columns in tables and figures. The
measurements may not be exact equivalents, therefore, each system must be used independently.
Tailoring
Tailoring of this process specification shall be formally documented as part of the program or project
requirements and approved by the responsible NASA Technical Authority. These requirements may be
tailored by constructing a matrix of applicable paragraphs and non-applicable paragraphs. Tailoring may
include using existing or previously developed contractor processes and standards as a submittal of the
various required plans. Otherwise, the tailoring of requirements may be documented in the Materials and
Processes Selection, Control, and Implementation Plan by providing the degree of conformance and the
method of implementation for each requirement identified herein.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 10 of 92
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APPLICABLE DOCUMENTS
Applicable Standards and Documents
The latest issues of the following documents form a part of this specification to the extent specified
herein. In the event of a conflict between the documents referenced herein and the contents of this
specification, the content of this specification will take precedence. The contractor may pursue
substituting equivalent specifications and documents to the ones identified herein as long as the
substitution does not compromise the intent of the specifications and documents identified herein and is
approved by NASA/MSFC before implementation.
Military
MIL-HDBK-1823 Nondestructive Evaluation System Reliability Assessment
MIL-A-18455 Argon, Technical
MIL-PRF-27401 Propellant Pressurizing Agent, Nitrogen
MIL-PRF-27407 Propellant Pressurizing Agent, Helium
BB-C-101 Federal Specification Carbon Dioxide (CO
2
): Technical and USP
BB-H-886 Federal Specification Hydrogen
CGA G-4.3 Commodity Specification for Oxygen
CGA G-5.3 Commodity Specification for Hydrogen
CGA G-6.2 Commodity Specification for Carbon Dioxide
CGA G-9.1 Commodity Specification for Helium
CGA G-10.1 Commodity Specification for Nitrogen
CGA G-11.1 Commodity Specification for Argon
National Aeronautics and Space Administration (NASA)
NASA-STD-5006A General Fusion Requirements for Aerospace Materials Used in Flight
Hardware
NASA-STD-5009 Nondestructive Evaluation Requirements for Fracture-Critical Metallic
Component
NASA-STD-5019 Fracture Control Requirements for Spaceflight Hardware
NASA-STD- 6016 Standard Materials and Processes Requirements for Spacecraft
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 11 of 92
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NASA-STD-8739.12 Metrology and Calibration
MPCV 7016 Cross Program Fluid Procurement and Use Control Specification
NPR 8715.1 NASA Occupational Safety and Health Program
NPR 1441.1 NASA Records Management Program Requirements
Other Publications
ASTM E8/E8M Standard Test Methods for Tension Testing of Metallic Materials
AWS A2.4 Standard Symbols for Welding, Brazing, and Nondestructive
Examination
AWS A3.0 Standard Welding Terms and Definitions
AWS A5-ALL Filler Metal Procurement Guidelines
AWS A5.01M/A5.01 Welding Consumables – Procurement of Filler Metals and Fluxes
AWS A5.12M/A5.12 Specification for Tungsten and Oxide Dispersed Tungsten Electrodes for
Arc Welding and Cutting
AWS B2.1/B2.1M Specification for Welding Procedure and Performance Qualification
AWS B4.0 Standard Methods for Mechanical Testing of Welds
AWS C6.1 Recommended Practices for Friction Welding
AWS C6.2 Specification for Friction Welding of Metals
AWS C7.4/C7.4 M Process Specification and Operator Qualification for Laser Beam
Welding
AWS D17.1 Specification for Fusion Welding for Aerospace Applications
AWS D17.2/D17.2 M Specification for Resistance Welding for Aerospace Applications
AWS D17.3 Specification for Friction Stir Welding of Aluminum Alloys for
Aerospace Applications
AWS G2.4/G2.4 M Guide for the Fusion Welding of Titanium and Titanium Alloys
AWS QC1 Standard for AWS Certification of Welding Inspectors
NAS 410 NAS Certification & Qualification of Nondestructive Test Personnel
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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NAS 1514 Radiographic Standard for Classification of Fusion Weld Discontinuities
SAE AMS 2680 Electron-Beam Welding for Fatigue Critical Applications
SAE AMS 2770 Heat Treatment of Aluminum Alloy Raw Material
SAE AMS-W-6858A Welding, Resistance: Spot and Seam
Reference Documents
The documents listed in Appendix H are provided as background information for users of this
specification, defining the source of the requirements in sections 4.0 through 11.0 of this specification.
The listing in this section does not levy any new or relieve any specific requirements that are imposed
by this specification or other contractual documents associated with procurement of this specification
end item.
Order of Precedence
When requirements in this specification conflict with those on the engineering drawing, the
requirements on the engineering drawing will take precedence. Conflicts between this specification
and other requirements documents will be resolved by the responsible NASA Technical Authority.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 13 of 92
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REQUIREMENTS
Safety
Industrial Safety
Appropriate personal protective equipment shall be used in all hazardous processes.
All hazardous materials and processes that are required in compliance with provisions of this
process specification and that are located or performed at sites other than MSFC are subject to
applicable federal, State, and local safety codes, standards, and regulations.
All hazardous materials and processes that are required in compliance with provisions of this
process specification and that are located or performed at MSFC shall be subject to NPR 8715.1.
System Safety
System safety engineering (SSE) shall identify critical and catastrophic hazards and
mitigations to eliminate and/or control the hazards of the welding operations.
SSE shall participate within the various program working groups, panel reviews, and
procedures and drawing reviews of welding systems and processes.
SSE shall participate in welding process reviews and decisions to ensure that safety concerns
are addressed and appropriate safety requirements and design criteria are implemented in accordance
with applicable program Safety, Reliability, and Quality Plan.
Specific Process Weld Requirements
Resistance Welding
Resistance welding shall be in accordance with AWS D17.2/D17.2M, or SAE AMS-W-6858A.
Laser Beam Welding
LBW shall be in accordance with AWS C7.4/C7.4M.
Friction and Inertia Welding
Direct drive friction or inertia welding shall be in accordance with AWS C6.2.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 14 of 92
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JOINT CLASSES
Inspection Criteria
Welds performed using this process specification shall be classified in accordance with the
consequences of joint failure as described in the following sections.
Welds shall be inspected per Table I.
Table I. Minimum Inspection Requirements
Method of Inspection
Weld Class
A
B
C
Visual
X
X
X
Dimensional
X
X
X
Surface
X
X
–
Volumetric
X
X
1
–
Additional Inspection When Required by Drawing
X
X
X
1
Class B welds shall be subjected to volumetric inspection if required by engineering design and
specified by drawing or special instruction.
Joint Classifications
Class A Joints
A weld joint whose failure would result in loss of crew, loss of vehicle, or loss of mission
shall be classified as a Class A joint.
Class A welds shall pass quantitative surface and volumetric NDE and visual inspection in
accordance with Table I and Section 11.0.
Class A fillet welds shall require a Materials Usage Agreement (MUA) in accordance with
NASA-STD-6016.
Based on consequences of failure, all fracture-critical welds are, by definition, Class A joints. If the quality of
the Class A joint cannot be verified as required by this specification, e.g., inaccessible volume or root surfaces,
then alternative rationale for acceptance is to be presented to the responsible NASA Fracture Control Board for
approval as required by NASA-STD-5019.
Class B Joints
A fail-safe weld joint shall be classified as a Class B joint.
Class B welds shall pass quantitative NDE and visual inspection in accordance with Table I
and Section 11.0.
Class C Joints
A nonstructural weld joint shall be classified as a Class C joint.
Class C welds shall pass a visual inspection in accordance with Table I and Section 11.0.
Class C welds shall be fully contained so failure in service would have minor or no effect on
the efficiency of a system and so endangerment to personnel would not occur.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 15 of 92
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EQUIPMENT
Welding Equipment
All welding equipment shall be capable of producing welds that meet the quality requirements
specified herein.
Welding equipment shall be procured in accordance with an approved specification.
Equipment parametric fluctuations, variations that occur in equipment without human
intervention, shall be characterized by the equipment vendor and may not be cause for rejection.
Violations of tolerances related to equipment variations during the steady-state portion of the
weld that occur for less than 6 seconds shall not be cause for rejection.
Variations caused by the sampling rate per second can cause the readings to be outside the certified range. As
long as the number is random (hence, the 6-sec limit), it is not cause for rejection.
Weld parameters controlling the heat input for automatic and mechanized welds shall be
recorded continuously using automatic recording devices during the weld operation.
Process parameter data shall be logged at a rate that sufficiently captures all essential variable
data and minimizes the risk of signal artifacts.
The minimum recommended data capture rate for FSW is 5 Hz.
Process parameter log files shall be stored electronically in compliance with contractual
requirements
Equipment fluctuations or natural variations that occur in equipment without human
intervention and change the readings of the qualified nominal parameter settings shall not be cause for
rejection.
EBW equipment shall be a high vacuum type for welding in 5x10
-4
torr [6.7x10
-2
Pa] (or better)
vacuum.
Acceptance Testing
New or relocated welding machines shall be acceptance tested under the cognizance of the
responsible organization before release to manufacturing departments for production welding.
Equipment shall meet the requirements of the applicable purchase specification or design
specification.
All equipment (electrical and mechanical) shall operate reliably within the range of
parameters and duty cycle to be used for welding of production parts.
Calibration
Calibration shall be in accordance with NASA-STD-8739.12. For MSFC operations,
reference MPR 8730.5 in Appendix H.
Welding shall be accomplished using equipment containing calibrated data indicators within
manufacturer-specified tolerance ranges that display and/or record welding parameters.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 16 of 92
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Measuring instruments, meters, gauges, or direct reading electrical control circuits to be used
for welding operations shall be calibrated.
Calibration shall be verified periodically at intervals specified by the manufacturer of the
welding equipment, not to exceed 1 year, or when any maintenance or repair is performed that may
have changed calibration.
Current calibration status shall be posted or made available at the equipment and verified prior
to use.
Calibration record(s) shall be maintained by the responsible cognizant organization and made
available upon request.
The office of record for MSFC calibration records is the MSFC Metrology and Calibration Laboratory.
Maintenance and Maintenance Records
A preventive maintenance plan shall be implemented for welding equipment.
Welding machines shall have adequate periodic preventive maintenance service.
A current record of each maintenance repair shall be maintained for each welding machine.
Maintenance records shall be maintained by the responsible cognizant organization and made
available upon request.
Records shall include unique identification of equipment, date, and time of service/repair,
description of work completed, and traceability to employee performing the maintenance.
Weld Equipment Modification
Weld equipment validation shall be required when the welding equipment has failed to
accomplish the intended function or when any major modification is made to the equipment.
Major modifications may include any changes to relevant sensor equipment, support hardware,
software, or the weld system affecting process control.
When any major modification is made to the equipment a validation plan shall be submitted to
the responsible NASA Technical Authority for approval.
Equipment validation documentation shall be retained as temporary records per section 11.3.7
and made available upon request.
Tooling and Fixtures
General Requirements
Tooling and fixtures shall be identified in the Weld Procedure Specification (WPS).
Tooling and fixtures used in the welding operation shall be constructed of materials that do
not adversely affect the weld process and are not detrimental to the weld quality.
Tooling and fixtures shall not be a source of contamination of the weld or of the part being
welded.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 17 of 92
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Fixtures within 2 in. [5 cm] of the weld joint shall be visually free from rust, oxide scale, dirt,
oil, grease, paint, low melting alloys, e.g., lead, tin, cadmium, and other contaminants detrimental to
weld quality.
Paint may be within 1 in. [2.5 cm] on FSW fixtures.
Clamping and Alignment
Tooling and fixtures shall maintain component alignment during welding and ensure
compliance with dimensional requirements of section 10.3 of this process specification.
In FPW, there shall be contact between the component and the backing anvil.
Magnetic Materials
When used with arc or EBW, magnetic materials shall be degaussed before welding.
Degaussing of magnetic materials shall be controlled by the WPS when necessary for the
successful completion of the weld.
Degaussing – Prior to welding, ferromagnetic parts or tooling which have been subjected to
the influence of magnetic fields (e.g., GTAW tack welded, machined using magnetic chucks, or
magnetic particle inspected) shall be degaussed prior to welding.
Degaussing is to prevent arc and electron beam deflection while welding the joint.
Chill Bars
Chill bars shall not be used in such a manner that the weld joint location surfaces pick up chill
bar material.
Chrome-plated copper chill bars may be used because copper or copper alloys have resulted in liquid metal
embrittlement of austenitic stainless steels and some cobalt alloys.
Electroless nickel plating introduces phosphorus, which is detrimental to the weld process.
Aluminum, aluminum alloys, or other low melting alloys shall not be used for chill bars for
non-aluminum alloy weld joints.
Electron Beam Welding
EBW shall be performed in a vacuum with absolute pressure of 0.001 torr [0.133 Pa] or lower.
Back-up material used to deflect or absorb residual EBW energy shall be of the same alloy as
the part being welded, except when authorized by the NASA Technical Authority.
Alternate back-up materials may be used when specified by the WPS.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 18 of 92
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MATERIALS
Base Metals
Unless otherwise specified or approved by the procuring agency, the base metal alloy shall
conform to applicable material specifications as defined on the engineering drawing.
The base metal type and condition, as well as the appropriate material specification shall be
recorded as a part of the WPS.
Weld start and run-off tabs, when used, shall be of the same alloy as the material being joined
and be welded with the same filler metal specified on the drawing or WPS.
Backing material may be used when authorized by the WPS.
Filler Metals
Weld filler materials shall be purchased according to AWS A5.01/A5.01M.
Unless otherwise specified or approved by the procuring agency, filler metal alloy shall
conform to all AWS A5 filler metal material specifications (AWS A5-ALL).
Weld filler materials and the appropriate specifications shall be recorded on the WPS.
Weld filler materials shall be stored under conditions to maintain filler material cleanliness and
quality.
Uncoated weld filler wires shall be identified with a unique identification placed at the lowest
level of control, i.e., wire, package, tube, to ensure material traceability of all uncoated welding filler
wires.
Recommended weld filler metals are listed in Appendix F.
Metal consumable inserts shall be certified, their material traceability maintained, and both
recorded as part of the WPS.
Material traceability for friction plugs shall be ensured.
Commercially pure titanium filler metal shall not be used for joining Ti-6Al-4V weld joints.
Shielding Gas
Welding-grade gases conforming to the applicable industry or military specifications shall be
used for gas shielding when required.
Argon gas shall conform to the requirements of MIL-A-18455 or CGA G-11.1.
Nitrogen gas shall conform to the requirements of MIL-PRF-27401 or CGA G10.1.
Oxygen gas shall conform to the requirements of CGA G-4.3.
Helium gas shall conform to the requirements of MIL-PRF-27407 or CGA G-9.1.
Hydrogen gas shall conform to the requirements of BB-H-886 or CGA G-5.3.
Carbon dioxide gas shall conform to the requirements of BB-C-101 or CGA G-6.2.
The shield gas type and flow rates shall be recorded as a part of the WPS.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 19 of 92
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Inert gas back-side shielding shall be used on joints requiring full or partial penetration on
alloys susceptible to heavy oxide formation on the root side, the formation of which cannot be removed
by wire brushing and will interfere with surface inspection.
Only helium or argon shielding gas shall be used for welding titanium and titanium alloys.
Tungsten Electrodes
Tungsten electrodes shall conform to AWS A5.12/A5.12M.
The electrode diameter, tip shape and alloy shall be recorded as a part of the WPS.
FSW Pin Tools
FSW pin tools (shoulders and pins) and tack tools shall be made of materials that resist wear
during welding.
Pin and shoulder service life shall be demonstrated to meet the intended use and the use of pins
and shoulders limited to the demonstrated life.
Pins and shoulders that have reached the specified service life shall be marked and removed
from service to preclude accidental future use in the FSW production process.
If used for more than one weld joint, pins and shoulders shall be cleaned and inspected as
required before reuse on production hardware.
Pin tools shall be visually inspected after each production weld for unacceptable wear and
damage. Cracks, pits, flakes, and missing or broken threads shall result in the rejection of the pin tool
from use in production.
Findings of pin tool visual inspections shall be recorded and hardware welded with damaged pin
tools dispositioned before acceptability for use.
Pin tool design and materials shall be recorded as part of the WPS.
Anvils and Plug Weld Backing Material
Unless otherwise specified or approved by the procuring agency, anvil materials shall conform
to applicable government and/or industry specifications for each given alloy group.
Anvil material shall be resistant to deformation under the loads and temperatures experienced
during C-FSW and FPPW.
Anvil material shall not chemically react with the components to be joined.
Anvil and plug weld backing materials shall be recorded as part of the WPS.
Friction Plugs
Unless otherwise specified or approved by the procuring agency, friction plug materials shall
conform to applicable government and/or industry specifications for each given alloy group and their
material traceability be ensured.
Plugs shall be stored in an area that precludes their degradation by humidity, contamination, or
chemical attack.
Plug weld design and material shall be recorded as part of the WPS.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 20 of 92
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WELDER PERFORMANCE AND WELD PROCEDURE QUALIFICATION
Welder Performance Qualification
Operators of welding equipment shall be certified by successful completion of a qualification
test for the applicable process.
Each fusion welder or fusion welding operator shall be qualified in accordance with AWS
D17.1, Section 5 and accepted to Class A requirements of this process specification.
7.1.1.1.1 All qualification groove welds shall be radiographically inspected.
7.1.1.1.2 All fillet welds with a base metal thickness more than 0.063 in [1.6 mm] shall be bend tested
or examined metallographically.
Other requirements may be added but not be substituted for the requirements in AWS D17.1 Section 5.
FSW operators shall be qualified in accordance with AWS D17.3, Section 7 and accepted to
Class A requirements of this process specification.
FPW operators shall be qualified in accordance with AWS D17.3, Section 7, using a square
groove test weld in sheet for making plug welds accepted to Class A requirements of this process
specification.
Welder qualification testing shall be repeated at intervals not exceeding 5 years or when there is
evidence to question the ability of the welder or welding operator to meet the requirements for
qualification.
To maintain qualification, welders and welding operators shall have performed the weld process
on the alloy groups for which they are certified within the previous 6 months.
Proficiency demonstration shall be required if a welder or welding operator has not performed
the weld process on the alloy groups for which they are certified within the previous 6 months.
Records of operator certification documentation shall be maintained by the contractor’s quality
assurance organization as temporary records per section 11.3.7 and be provided to the procuring agency
before welding flight hardware.
Weld Procedure Specification
A WPS shall be qualified for each thickness and material combination. The allowable qualified
thickness range is shown in Table II.
The WPS shall be qualified on the production equipment before welding of the first production
part.
Table II. WPS Allowable Qualified Thickness Range
Process Application
Thickness (t) Range, in [mm]
Automatic
±0.020 [0.51]
Semi-Automatic
±0.020 [0.51]
Mechanized
±0.020 [0.51]
Manual
-0.5t / +2.0t
Orbital Tube
±0.1t
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 21 of 92
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Appendix E lists information that may be included in a WPS.
All test and evaluation data shall be recorded in the PQR.
The WPS shall contain all the information necessary to produce welds that consistently meet the
strength and quality requirements.
All essential variables shall be identified on the WPS.
For weld qualification tests, base metal and consumables shall be identified by lot or heat
number, type, and condition.
This base metal and consumable identification shall be maintained through all evaluation
processes.
The WPS shall document all other prewelding operations, setup conditions, welding
equipment, and any other pertinent information about the welding system used that affects the welding
operation.
Operator trim parameter tolerances used for automatic, semi-automatic, and mechanized
welding shall be listed in the qualified WPS.
Test samples representing the minimum and maximum heat input bounded in the WPS for
automatic, semi-automatic, and mechanized welds shall be tested in accordance with section 7.3 of this
process specification to verify acceptable welds
Procedure qualification welds shall be inspected using visual and NDE as specified in section
10.0 of this process specification, in accordance with Class A requirements.
Following visual and nondestructive inspection, the qualification welds shall be subjected to
the same processes as the production parts, including reinforcement removal, mechanical deformation,
stress relief, and thermal treatments associated with artificial aging or any operation affecting
mechanical properties.
Rejectable surface indications may be removed using mechanical means (sanding or
polishing), not rewelding. All visual and surface indications noted on the qualification welds that have
been mechanically removed shall be recorded in accordance with section 7.3.1 and the records retained
with the qualification weld documentation.
Operating ranges for current and voltage shall be established during the WPS qualification for
the steady-state portion of manual welds.
Tapered thickness welds shall be qualified at the maximum and minimum thickness (see
Table II) and with a full-length confidence weld (specified in section 7.3.4).
In recognition of the differences in welding conditions between a test panel fixture and a major
weld tool, the weld schedule developed on the test panel fixture shall be adjusted to the degree
necessary when welding on the major weld tool.
The variation shall be noted on the WPS.
The adjustment shall be allowed one time only on the first part welded on the major weld tool.
An adjustment approach that allows more than one adjustment shall be approved by the
responsible NASA Technical Authority.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 22 of 92
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A confidence weld shall be completed before welding production hardware in accordance
with the requirements of 7.3.4.
Procedure Qualification Records
All test results, including visual, dimensional, and NDE, shall be recorded in the PQR.
The provisions of AWS B2.1/B2.1M, may be followed for fusion welds.
Weld Testing Methodology
Welds shall be tested in accordance with AWS B4.0. Alternative methods for weld performance
qualification verification shall be approved by the NASA Technical Authority.
For FSW, weld process zones should be evaluated using the qualified WPS at panel and confidence weld level.
Weld process zones may include intersections, weld overlap regions, restarts and closeout processes. This data
should be evaluated to the vehicle design requirements.
Tensile Tests
7.3.2.1.1 A minimum of five specimens shall be tested to qualify a groove weld procedure.
7.3.2.1.2 Plug weld tensile test specimens gauge width shall be a minimum of 1.3 times the major
diameter of the plug weld.
7.3.2.1.3 At a minimum, tensile specimens shall be tested to destruction at room temperature.
7.3.2.1.4 Percent elongation in 1.0 in. [2.5 cm] and/or 2.0 in. [5 cm] gauge lengths, 0.2% offset yield
stress, and ultimate tensile strength shall be recorded.
7.3.2.1.5 Percent elongation for round samples shall be measured across a length of 4 times the
diameter.
7.3.2.1.6 Weld strength shall meet or exceed the values in Appendix A.
7.3.2.1.7 Qualification welds for aluminum alloys used in cryogenic applications shall be tensile
tested at the intended use cryogenic temperature and at room temperature.
A minimum of four test specimens shall be tested to destruction.
Shear Tests
7.3.2.2.1 A minimum of five specimens shall be shear tested for fillet welds in corner, T, lap, or edge
joint configuration to qualify the weld procedure.
When it is not feasible to fabricate shear test specimens from qualification welds, shear tests may be
implemented in accordance with AWS B4.0.
7.3.2.2.2 The shear ultimate strength shall meet 60% of the weld ultimate tensile strength requirement
shown in Appendix A, unless otherwise approved by the responsible NASA Technical Authority.
Metallographic Examination
7.3.2.3.1 The welded joint shall be sectioned transverse to the direction of welding and the surface
adequately prepared for visual examination in an unetched condition at a magnification of 10X for weld
characteristics and defects.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 23 of 92
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7.3.2.3.2 The section shall be lightly etched to reveal microstructure and reexamined at a higher
magnification (a minimum of 50X and not greater than 200X) for dimensional requirements and the
following weld quality requirements:
Overall fusion or consolidation of the weld, root penetration, burn-through, and blowholes.
Convexity, concavity, and size of bead, nugget or fillet.
Undercutting, underthickness, and overlapping.
Inclusions or voids.
Cracks.
Titanium Chemistry
7.3.2.4.1 Titanium weld qualification samples shall be analyzed for hydrogen, oxygen, and nitrogen
content, in accordance with the requirements of the base metal specification, to assure conformance to
the purity requirements.
7.3.2.4.2 The level of interstitial gases in the completed weld shall not exceed the worst-case
maximum level permissible in the procurement specification for the base materials being welded.
7.3.2.4.3 The weld cross section in titanium welds shall contain no titanium hydrides (TiH
2
) or alpha
case.
These two detrimental phenomena are indications of the hydrogen content exceeding the solubility limit and an
oxygen-enriched alpha-stabilized surface resulting from air contamination at elevated temperatures,
respectively.
Specimens described in section 7.3.2 of this process specification shall be produced and tested
at a minimum interval of 5 years for Class A and Class B welds to verify PQR data.
Failed qualification welds that have anomalies with a clear definable cause may be repeated with a 2-for-1
replacement.
Additional testing (fatigue, simulated service, hardness, impact, etc.) may be performed in support of meeting the
design requirements.
Confidence Weld Requirements
A confidence weld for each of the following different weld configurations shall be made and
tested in accordance with section 7.3.2 of this process specification to validate the WPS. Class C welds
are not required to have a confidence weld performed for qualification.
7.3.4.1.1 Tapered thickness welds made with automatic, semi-automatic, or mechanized weld
processes.
7.3.4.1.2 Pressure vessel or pressurized structure welds; excluding pressurized component welds.
7.3.4.1.3 All SR-FSW.
7.3.4.1.4 All C-FSW.
7.3.4.1.5 Cases in which the procedure qualification weld does not provide an appropriate
representation of the product form, e.g., forging, casting, extrusion, or geometry of the components
being welded, e.g., tubing, rolled shape.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 24 of 92
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7.3.4.1.6 Class A weld without root side access to verify full penetration.
7.3.4.1.7 Primary structural vehicle or payload welds. This may include payload attachment
hardware or similar structures that constitute the primary load path within or between the vehicle and
payload.
The confidence weld shall replicate the production part with respect to section thickness,
alloy, heat treat condition, joint preparation, preweld cleaning, and fit-up and be made in the actual
production weld fixture, using the actual production welding equipment.
The confidence weld shall replicate the production weld with respect to length, startup, and
tailout or closeout.
7.3.4.3.1 A minimum of 15 total specimens shall be tested from the confidence weld(s).
Five specimens shall be taken from the beginning, five specimens from the middle, and five
specimens from the end of the confidence weld. Specimen removal locations shall be approved
by the NASA Technical Authority.
a) Beginning – As near the weld start as part geometry allows but outside of any overlap
region
b) Middle – As near the weld midpoint as part geometry allows
c) End – As near the weld end as part geometry allows but prior to any overlap region
In FSW, the closeout process shall be tested at the service temperature.
For weldments of insufficient size or configuration, the NASA Technical Authority shall
approve the test approach.
The pathfinder article may be used for the confidence weld if the above criteria are met.
Qualification shall be required if any of the essential variables on the WPS are modified.
Records
Records of test specimens that meet the acceptance requirements of this process specification
shall be signed and dated by a Safety Mission Assurance (SMA) representative as an accurate record of
the welding and testing of the procedure test weldment.
The WPS and PQR shall be prepared and retained as temporary records in accordance with
section 11.3.7, with the current WPS being accessible at the welding station to the welder or welding
operator.
All WPSs and PQRs shall be maintained and made available for review by the responsible
NASA Technical Authority before production.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 25 of 92
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PREWELD OPERATIONS
Weld Joint Design
Joint configurations shall be documented in the WPS and on the design drawing.
Acceptable joint designs are butt, lap, corner, T, and edge. Corner and T joint designs should be designed to
minimize susceptibility to lamellar tearing.
Class A and Class B full-penetration weld joint configurations that will be inaccessible for root
side inspection are subject to the requirements of section 7.3.4 and shall be identified on engineering
drawings and require approval for use as a weld joint design by the responsible NASA Technical
Authority.
For Class A welds, faying surfaces of joints shall have a surface roughness of 32 to 125 µin
[0.81 to 3.2 µm] per ASME B46.1.
LBW and EBW weld joint edges shall be machined parallel to ensure proper fit-up and meet the
preweld joint fit-up requirements in Appendix B.
FSW joint design shall be butt joint configuration only.
Plug weld joint preparation shall be performed per the WPS or Engineering Drawing. This may
include deburring.
Preweld Cleaning
Preweld cleaning of contaminants detrimental to weld quality or filler materials and surfaces to
be welded shall be in accordance with Appendix G.
Preweld cleaning shall be accomplished in a controlled environment that does not degrade weld
quality and that is maintained until the weld operation is complete.
After surface preparation, parts shall be covered or otherwise protected to prevent
contamination until welding is completed.
Personnel performing the cleaning operation or any subsequent operation shall wear powder-
free, non-vinyl, moisture barrier gloves.
Before use, tooling (including hold-down clamps, anvils, and parts of welding fixtures that
contact or are placed in close proximity to the weld joint) shall be free of oil, moisture, and foreign
materials.
Tools and instruments used for measurements or other devices that contact the surfaces to be
welded shall be free of oil, grease, moisture, or other foreign materials before use.
Tools shall be cleaned initially and intermittently as necessary.
Preweld and interpass cleaning requirements shall be included in the WPS.
Stainless steel wire brushes shall be used in all instances where wire brushing is performed.
Low-current (10 ampere maximum), reverse–polarity, high-frequency arc cleaning (using manual, automatic,
semi-automatic, or mechanized welding equipment) may be used to remove oxides from iron-, nickel-, and
cobalt-base alloys.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 26 of 92
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Fusion welding shall be started within 24 hrs. of initiating preweld cleaning, unless otherwise
permitted by the responsible NASA Technical Authority.
Time between initiation of preweld cleaning and welding shall be documented in production
build records.
In aluminum alloys, C-FSW joints will subsequently be intersected by fusion welds shall be
cleaned by draw filing or scraping the abutting edges and scraping or wire brushing the crown and root
surfaces of the weld land 0.5 in [12.7 mm] beyond the shoulder diameter.
All SR-FSW joints in aluminum alloys shall be cleaned by draw filing or scraping the abutting
edges and mechanically abrading the crown and root surfaces of the weld land 0.5 in [12.7 mm] beyond
the shoulder diameter.
Following the mechanical cleaning operations described in sections 8.2.11 and 8.2.12 above, solvent cleaning by
wiping with lint-free clean cloth may be permitted.
The FSW full-penetration pass shall be started within 48 hrs. of initiating preweld joint cleaning
unless otherwise permitted by the responsible NASA Technical Authority.
Tack welding is not considered a full-penetration weld.
EBW shall start within 40 hrs. after surface preparation has been completed, unless otherwise
permitted by the responsible NASA Technical Authority, with the following exceptions:
EBW of aluminum alloys shall be performed within 8 hrs. after being cleaning.
If parts have been vacuum dried and stored in a sealed plastic film (other than polyethylene or
nylon) bag purged with dry argon or gaseous nitrogen, the parts shall be welded together within 100
hrs. of cleaning.
Weld joints adjacent to brazed surfaces shall be cleaned in accordance with Appendix G to
remove contamination from brazing operations.
All brazing alloy deposits shall be removed from the weld joint region that includes the joint
and the area within 0.25 in [6.4 mm] of the joint, unless otherwise specified on the engineering
drawing.
When welding precision-cleaned hardware, all welding of assemblies for precision-cleaned
systems (including tube preparation) shall meet the requirements of MPCV 7016.
Plugs used for friction plug welding and the material to be plug welded shall be cleaned by
abrasion to remove the oxide layer, followed by solvent cleaning within 8 hrs. of plug welding.
Preweld Joint Fit-up
After the parts have been mated, positioned and tacked for the welding operation, the joint shall
be verified for compliance with the preweld and postweld dimensional requirements of Appendix B of
this process specification.
Preweld joint gap requirements for specific materials and processes shall meet the requirements
listed in Appendix B.
The interrelationship of mismatch, joint gap, peaking, and pin tool offset shall be shown by
engineering analysis or test to assure that positive margins of safety exist for FSW.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 27 of 92
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Weld Start and Run-Off Tabs
Weld start and run-off tabs (when used) shall be of the same alloy as the detail parts being
welded.
Weld start and run-off tabs shall be cleaned in the same manner as the parts.
Tabs shall be integral with the part, being either machined in, welded with the same filler metal,
or rigidly attached to the part pieces before assembly.
Length of weld start and run-off tabs shall be established, based on the confidence panel test
results.
Use of weld start and run-off tabs shall be included in the WPS.
Laser and Electron Beam-to-Joint Alignment
Flat and Circular Welds
Before welding every weld joint of every production run, the entire length of the joint shall be
leveled to within ±0.005 in [±0.127 mm] using a calibrated dial indicator.
The assumed centerline of the beam shall be aligned within 30 min of the gun angle defined in
the approved weld parameter, as determined using a calibrated inclinometer in conjunction with a
surface at a known reference angle to the joint faces.
Circumferential Welds
Before welding every weld joint of every production run, the axis of the assembly shall be
leveled, using a calibrated dial indicator to within ±0.005 in [±0.127 mm] in relation to reference
surfaces for weld joint faces perpendicular to the axis.
For off-axis joints, the assumed centerline of the beam shall be aligned within 30 min of the
gun angle defined in the approved weld parameter, using a calibrated inclinometer in conjunction with
a surface at a known reference angle to the joint faces.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 28 of 92
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PRODUCTION WELDING
Equipment Operational Readiness Check
A welding equipment operational readiness check shall be made immediately before a production weld
to verify that the equipment is operating properly.
An equipment checklist may be used to ensure equipment performance. Items such as pintool part and serial
number(s) (FSW), torch setup (fusion), air pressure, water pressure, shield gas flow, and other factors affecting
equipment performance may be verified before weld initiation.
Temperature Control.
Preheat, interpass, and postheat temperatures shall be controlled so as not to degrade the
properties of the material being welded.
These parameters shall be recorded in the applicable WPS.
Tack Welding
Tack welding shall be allowed, provided they are fully consumed by the final weldment.
After the final weldment is completed, the tack areas shall be inspected to the requirements of
the finished weld.
Tack welding parameters shall be included in the WPS and used to generate PQR data.
Tack welding parameters are not essential variables.
Aluminum alloy joints to be FSW shall be tacked using FSW unless authorized by the
responsible NASA Technical Authority.
Other tacking methods may be used provided requirements 9.3.1, 9.3.2 and 9.3.3 are met.
A tack weld made with EBW or LBW shall be made with a substantially reduced power density
from the certified full-penetration pass, up to and including the full length of the weld.
A full-penetration tacking pass using certified parameters may be used.
If a full-penetration tacking pass using certified parameters is used, it shall not exceed
10 percent of the weld joint length for EBW.
If a full-penetration tacking pass using certified parameters is used, it shall terminate in the
weld start and run-off tabs when applicable.
Welding Techniques
Square groove welds shall be completely penetrated from one side (Figure 1A).
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 29 of 92
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Figure 1. Welding Techniques
Partial-penetration groove welds shall be used only for Class C joints, unless approved by the
responsible NASA Technical Authority.
Two-sided welding of butt joints (Figure 1B) shall only be allowed under the following
conditions:
The weld shall be performed in a prepared groove joint (Figure 1C and Figure 1D), where it
can be verified the initial pass consumed the entire abutting edge.
Partial-penetration welds from one side shall be machined into the penetration root to sound
metal before completing the next pass.
At a minimum, visual inspection shall be used to ensure penetration.
Welding Procedure
A specific WPS for each weld shall be required for all production welds in accordance with the
requirements of section 7.2.1.
Procedure Departure
Any departure from the qualified WPS during production welding shall require withholding of
the component for MRB disposition, except as noted in section 5.1.4.
MRB records shall be maintained as temporary records per section 11.3.7.
The cause for departure shall be determined and corrective action taken before further
production welding.
Cosmetic weld bead / passes shall only be allowed if included in a qualified WPS.
After welding, the EBW vacuum chamber shall not be vented until the component has cooled to
a temperature below its oxidizing temperature, as specified in the qualified WPS.
SR-FSW shall be welded with the pin tool offset toward the retreating side of the joint in
accordance with Appendix B.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 30 of 92
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POSTWELD OPERATION
The Weldment
Each completed weldment (both face and root sides) and the adjacent base metal for a minimum 0.5 in
[12.5 mm] on either side of the weld shall be inspected to ensure compliance with the requirements of
sections 10.2, 10.3, and 10.6 as dictated by the class of the weld, unless approved by the responsible
NASA Technical Authority.
General Workmanship Requirements
Uniform appearance of weld deposits, buildup, and root reinforcement shall be verified by visual
confirmation.
The face and root sides shall be free of surface cracks, crater cracks, other defects open to the
surface, and oxide scale.
Visual inspection of the root surface of C-FSW may be omitted if etch and dye penetrant inspection are
performed.
The weld deposits shall be free of open voids or unfused overlapping folds.
For fusion welds the edge of the weld deposit shall blend smoothly into the base metal without
unfused overlaps or undercuts.
Titanium alloy welds and adjacent base metal shall meet the color requirements of AWS
G2.4/G2.4M.
With the exception of titanium alloys, discoloration caused by vapor deposition during EBW may be acceptable.
The surface of FSW shall be free of galling, tears, or blisters.
By-products of the welding process, such as weld-spatter, oxide scale, soot, flash, or other by-
products, shall be removed from the welded component.
Dimensional Requirements
Welded Butt Joints
Welded butt joints shall have 100% penetration.
Welded butt joints shall meet the geometrical requirements in Appendix C.
The root bead width in fusion welds shall not exceed the maximum weld width specified in
Appendix C.
The allowable postweld mismatch (Figure 2) shall not exceed the values specified in
Appendix B.
The allowable postweld peaking (Figure 2) of the welded joint and adjacent base metal shall
not exceed the values in Appendix B.
A standard template or other calibrated electronic measurement device having specified
reference points shall be used for determination of peaking and mismatch.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 31 of 92
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Figure 2. Mismatch and Peaking
The combined effect of mismatch and peaking on the efficiency of the weld joint is such that one can be
increased if the other is decreased. A limited amount of mismatch and peaking greater than the values
in Appendix B can be tolerated if it can be shown by engineering analysis or test that positive margins
of safety exist.
Weld Reinforcement Removal
Weld reinforcement, both face side and root side, shall remain, unless specified by the
engineering drawing.
The weld bead reinforcement may also be removed to eliminate defects occurring in the outer zones of
the reinforcement unless otherwise specified on the engineering drawing.
For fusion welds, reinforcement removal shall not thin the weld or base metal below drawing
dimensional requirements.
When flush contour is required by the welding symbol, weld reinforcement shall not exceed
0.015 in [0.4 mm].
Metal removal shall be such that the mechanically reworked area blends smoothly, e.g., 0.125
in [3.2 mm] radius, with adjacent material without abrupt sectional changes.
Surface roughness, after reinforcement removal, shall not exceed 250 µin [0.006 mm] or the
specification on the drawing.
Grinding of base metal shall not be done when wall thickness cannot be verified after
grinding.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 32 of 92
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Flash material in solid-state welds shall be removed.
Techniques to remove flash, metal slivers, anvil marks on C-FSW and other sharp or raised
metal shall not interfere with postweld NDE inspections.
Material thickness shall not be reduced below the allowed underthickness specified in Appendix
C.
Weldments that are machined, ground, or otherwise mechanically worked causing disruption
or smearing of the material surface shall be etched to remove the masking material before penetrant
application.
Fillet Welds
The minimum acceptable fillet size shall be that specified by the engineering drawing.
The maximum acceptable fillet size shall be the size specified plus 50% or 0.188 in [4.8 mm],
whichever is less.
Figure 3. Fillet Weld Throats
When not specified on a drawing, the fillet sizes for superalloys given in Appendix C may be used.
For equal leg fillet welds, the fillet size is equal to the leg length of the largest inscribed right isosceles
triangle.
For unequal leg fillet welds, the fillet size is the leg length of the largest right triangle that can be
inscribed within the fillet weld cross section (A and B in Figure 3).
Fillet weld fusion of the root (Figure 4) shall have a minimum of 10% penetration of base
metal thickness of the thinnest member of the root of the joint as determined by evaluation of
transverse sections taken from the qualification welds.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 33 of 92
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Figure 4. Fillet Welds
Fillet welds terminating at corners with un-welded joints shall have the fillet continued around
the corner into the un-welded joint is a minimum of 0.125 in [3.2 mm], and a maximum of 0.5 in
[12.5 mm].
Toes of fillet welds shall blend smoothly with adjacent base metal.
The root of the weld shall penetrate to the extent that the actual throat dimension exceeds the
theoretical throat dimension as shown in Figure 3.
Weldment Straightening
Straightening of welds and adjacent base metal that have been deformed by the welding
operation shall be allowed only in accordance with a procedure approved by the responsible NASA
Technical Authority.
The straightening procedure shall be verified on test coupons using NDE, destructive testing,
and metallurgical examination to verify the process used for straightening does not degrade the weld
and surrounding material below the specified design requirements.
The straightening procedure shall be documented on the WPS.
Weldment straightening shall not be performed on welds failing to meet the acceptance criteria
described in section 10.6 of this process specification.
Following weldment straightening, the weld and adjacent base metal shall be inspected in
accordance with section 10.1 of this process specification.
Weldments with defects revealed by straightening operations shall not be acceptable.
Peening or Planishing
When specified on the engineering drawing, peening or planishing shall be performed in
accordance with a qualified WPS that was established based on welded and peened or planished
qualification test samples that simulate the material type and joint configurations to be used on the
production component in accordance with section 7.3.2 of this process specification.
Peening or planishing shall not be performed on cover passes or on welds less than 0.090 in
[2.3 mm] in thickness.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 34 of 92
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When interpass inspections are required by the engineering drawing, they shall be performed
before and after peening.
Postweld Heat Treatment Requirements
Weldments subject to heat treatment operations shall be inspected before and after heat
treatment in accordance with the quality requirements listed in section 10.6 of this process
specification.
Postweld heat treatment processing shall be as identified on the engineering drawing and the
heat treatment included in the WPS.
Weldment Quality Requirements
It is recommended a workmanship standard be developed for interpretation of acceptance criteria
when needed.
Surface Requirements
Surface requirements shall apply to the final weld condition, to the crown side of all welds, and to
the root side of full-penetration welds.
The surface acceptance requirements shall be as listed in Appendix D.
For penetrant inspection of unshaved VPPA weld root beads, transverse indications confined
to the width of the weld bead are acceptable except at weld intersections. Transverse indications
extending into the parent material or the toe radius are to be rejected regardless of length.
Volumetric Requirements
The volumetric acceptance requirements shall be as listed in Appendix D.
The radiographic linear indication at the root of the weld (Figure 4), which is inherent in the
design of fillet welds, shall not be considered a crack.
Workmanship standards should be developed to facilitate interpretation of fillet weld radiographic
linear indications.
Repair Welding
Additional welding operations shall be permitted to correct any unacceptable defect established
in accordance with section 10.6 of this process specification, provided the repair or rework welding
parameters and procedures are specified in a qualified repair WPS and the repair or rework is contained
within the original weld zone.
Complete records of the repair or rework welding operation, including identification of the
repaired or reworked weldment, type of defect, and location of the repair or rework weld, shall be
retained in accordance with NPR 1441.1.
Visual re-inspection and NDE of all repair weld areas shall be performed using the same
methods and requirements as used on the original weld.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 35 of 92
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All 2195 fusion weld repairs shall be planished to recover 70% of the shrinkage induced during
heat repair operations using qualified planishing procedures.
Material Review Board
MRB disposition shall be required when any one of the following conditions exists:
When more than two weld repair attempts have been performed at the same location on
materials that are heat sensitive.
When more than five weld repair attempts have been performed at the same location on
materials that are not heat sensitive.
When the wrong filler metal has been used.
When a repair weld is required after the weldment has been postweld heat treated.
When a repair weld is required after final machining has been completed.
When the repair extends outside the original weld zone (fusion zone and HAZ).
When a weldment has been direct aged, i.e., aged only without intermediate solution heat
treatment, unless authorized by the NASA Technical Authority.
When a weldment has been made with parameters outside the qualified WPS range.
All repairs of defective plug welds.
Weld repairs following proof or leak test.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 36 of 92
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VERIFICATION
General
The supplier shall be responsible for the performance and evaluation of all visual inspection and
NDE as required by this process specification.
The supplier shall use visual inspection and NDE facilities and services approved by the
procuring agency or through a vendor selection process approved by the procuring agency unless
otherwise specified.
The procuring agency or its designated representative reserves the right to perform any or all of the
visual inspections and NDE required to assure the end item conforms to the prescribed requirements.
NDE procedures to be used in inspection for weldment volumetric and surface quality
requirements shall be validated as being capable of detecting the acceptance criteria described in
Appendix D of this process specification before inspection of the first production weld.
Personnel performing visual weld inspections shall be certified to AWS QC1 or equivalent.
Additional information for certifying personnel to perform visual inspection and NDE of welds may be
found in MWI 3410.5.
Personnel performing NDE weld inspections shall be certified in accordance with NAS 410.
For inspection of fracture-critical welds, personnel performing NDE shall be, at a minimum,
certified Level II in accordance with NAS 410.
Dimensional inspection of joint fit-up quality requirements of FSW shall be performed
immediately prior to performing the full penetration weld per section 8.3 of this specification.
Postweld Inspection
The supplier shall certify that each semi-automatic, mechanized, and automatic production weld
was made within the range of operating parameters established in the qualified WPS and as allowed per
section 7.2.9.
Visual Inspection
The weld metal and adjacent base metal for a minimum distance of 0.5 in [12.5 mm] on either
side of the weld interface shall be visually inspected to ensure compliance for all weld classes with the
general workmanship requirements of section 10.2.
The weld shall be in the as-welded condition for the initial visual inspection, except that
surface smut and loose oxide have been removed in such a way that does not smear metal or change the
quality of the weld.
Titanium weld deposit and heat-affected zone discoloration shall be in accordance with the
accept/reject criteria requirements within AWS G2.4/G2.4M color chart.
For FSW scratches and tooling marks shall not be cause for rejection, provided they meet
surface finish requirements.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 37 of 92
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Indications attributed to anvil joint gaps or anvil gouges for C-FSW and FPPW shall not be
cause for rejection.
Dimensional Inspection
Dimensional inspection shall be performed on weldments of all weld classes to assure
compliance with the requirements of the design drawing for all weld classes and requirements in
section 10.3 of this process specification.
For FSW, within 1.5 in [38.1 mm] of an intersection weld minimal thickness shall be equal to
or greater than the minimum drawing thickness.
Volumetric Quality NDE
NDE methods shall be performed, as required by engineering drawing, to assure that the weldment
meets quality requirements for Class A and Class B welds, as applicable.
NDE procedures and techniques shall be qualified in accordance with NASA-STD-5009, and
with guidelines from MIL-HDBK-1823, for detectability of critical defect.
When reliability of inspection and critical flaw detection so dictate, redundant and/or
complementing inspection techniques and procedures shall be used.
Volumetric inspections may be waived for non-fracture-critical fillet welds when the specified fillet size
is increased 25% for Class A aluminum welds and 30% for Class A steel, corrosion- or heat-resistant
alloys, or 20% for Class B aluminum welds and 25% for Class B steel, corrosion- and heat-resistant
alloys, given prior approval by the responsible NASA Technical Authority.
Surface Quality NDE
NDE methods shall be performed to assure compliance with the surface quality requirements
as required by engineering drawing and those in section 10.6.1 and Appendix D of this process
specification for Class A and Class B welds.
NDE procedures shall be qualified in accordance with NASA-STD-5009 and with guidelines
from MIL-HDBK-1823 for detectability of critical defect.
When reliability of inspection and critical flaw detection so dictate, redundant and/or
complementing inspection techniques and procedures shall be used.
The supplier shall verify weldments subjected to mechanical working have been etched to
remove smeared metal before penetrant application.
Records
Records of a continuous audit of weldment production quality (including validation and
qualification of NDE procedures and techniques) shall be submitted and maintained in accordance with
contract requirements.
Resulting records shall include, but not be limited to, the location of repairs, type of defects
repaired, procedures used, inches of repair per total inches of weld, and number of repair attempts in
any one location.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 38 of 92
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The probability of detection (POD) capability documentation shall be retained as a temporary
record by the developing organization per section 11.3.7.
These records shall be accounted on a quarterly basis, with such accounting made available to
the responsible NASA Technical Authority.
Production build records, including visual inspection and NDE test records, shall be maintained
and made available upon request by the procuring agency or its designated representative.
Deviations from requirements in this specification shall be documented by tailoring, as defined
in section 1.4 and maintained as temporary records as defined in section 11.3.7 by the procuring agency
or its designated representative.
The Records Retention Schedule in NPR 1441.1 shall be flowed down through the contract.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 39 of 92
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Appendix A
Procedure Qualification Weld Strength Requirements
A.1 PURPOSE AND/OR SCOPE
This appendix contains procedure qualification weld strength requirements.
A.2 BUTT WELD ULTIMATE TENSILE STRENGTH REQUIREMENTS (ALUMINUM
ALLOYS)
The butt weld ultimate tensile strength requirements for aluminum alloys provided in Table III thru
Table VI shall be adjusted by the responsible NASA Technical Authority if product forms, temper, or
the base metal plate gauge cross section, i.e., t/6, used to qualify the weld procedure is other than thin
plate.
A.3 PROCEDURE QUALIFICATION TENSILE PROPERTIES
The values listed in this appendix for procedure qualification tensile properties are for qualification
only and shall not be used for design purposes.
A.4 ALTERNATIVE ULTIMATE TENSILE STRENGTH REQUIREMENTS
Alternative ultimate tensile strength requirements used for weld procedure qualification, shall be
approved by the responsible NASA Technical Authority.
This may include alloy combinations not listed in Table III thru Table VI.
A.5 JOINT EFFICIENCY
If joint efficiency is to be used to establish weld strength requirements then parent tensile specimens
shall be extracted from the product form panel in the same grain orientation as the welded samples.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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A.6 PROCEDURE QUALIFICATION WELD STRENGTH REQUIREMENTS FOR ALUMINUM ALLOYS
Table III. GTAW Process Butt Weld Ultimate Tensile Strength Requirements
Alloy
Base Metal
Temper
Base Metal Thickness (t),
in [mm]
Room Temperature
Cryogenic LO
2
Cryogenic LH
2
Min., ksi [MPa]
Avg, ksi [MPa]
Min. ksi [MPa]
Min., ksi [MPa]
2014
T6
<0.125 [<3]
43 [297]
45.5 [314]
0.125 ≤ t ≤ 0.25 [3 ≤ t ≤ 6]
40 [276]
42.5 [293]
>0.25 [>6]
38 [262]
40.5 [279]
2195
T8M4
≤0.25 [≤6]
40 [276]
42 [290]
48 [331]
52 [359]
0.251 < t ≤ 0.65 [6.4 < t ≤ 16.5]
38 [262]
40 [276]
45.6 [314]
49.4 [341]
2219
T81
All
38 [262]
40 [276]
T87
All
38 [262]
40 [276]
45.6 [314]
49.4 [341]
T3X¹
≤0.25 [≤6]
42 [290]
44 [303]
0.25 < t ≤ 0.5 [6 < t ≤ 13]
40 [276]
42 [290]
0.5 < t ≤ 0.75 [13 < t ≤ 19]
42 [290]
44 [303]
0.75 < t ≤ 1 [19 < t ≤ 25]
43 [297]
45 [310]
1 < t ≤ 1.25 [25 < t ≤ 32]
44 [303]
46 [317]
1.25 < t ≤ 1.5 [32 < t ≤ 38]
45 [310]
47 [324]
O/T8X
0.125 [3]
19 [131]
21 [145]
5052
All
All
25 [172]
28 [193]
5456
All
All
42 [290]
44 [303]
6061
T4
All
24 [166]
27 [186]
T6
All
24 [166]
27 [186]
¹Applicable to tempers that require an aging cycle of 350 (±10) °F [177 (±5) °C] for 18 hrs. in accordance with SAE AMS 2770.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 41 of 92
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Table IV. VPPA Process Butt Weld Ultimate Tensile Strength Requirements
Alloy
Base Metal
Temper
Base Metal Thickness (t),
in [mm]
Room Temperature
Cryogenic LO
2
Cryogenic LH
2
Min., ksi [MPa]
Avg., ksi MPa]
Min., ksi [MPa]
Min., ksi [MPa]
2195
T8M4
≤ 0.25 [6]
40 [276]
42 [290]
48 [331]
52 [359]
0.25 < t ≤ 0.65 [6.4 < t ≤ 16.5]
38 [262]
40 [276]
45.6 [314]
49.4 [341]
2219¹
T87
≤0.4 [10.2]
38 [262]
40 [276]
45.6 [314]
49.4 [341]
0.4 < t ≤ 0.75 [10.2 < t ≤ 19.0]
36 [248]
39 [269]
43.2 [298]
46.8 [323]
0.75 < t ≤ 1.1
[19.0 < t ≤ 27.9]
35 [241]
38 [262]
42 [290]
45.5 [314]
2219²
T87
≤0.33 [8.4]
38 [262]
40 [276]
45.6 [314]
49.4 [341]
0.33 < t ≤ 0.360 [8.4 < t ≤ 9.1]
37 [255]
38.5 [265]
43.2 [298]
46.5 [321]
2195/2219
T8M4/T87
<0.25 [6]
40 [276]
42 [290]
48 [331]
52 [359]
0.25 < t ≤ 0.650 [6 < t ≤ 16.5]
38 [262]
40 [276]
45.6 [314]
49.4 [341]
¹Vertical Position
²Flat and 45° Positions.
Table V. FSW Process Butt Weld Ultimate Tensile Strength Requirements
Alloy
Base Metal
Temper
Base Metal Thickness (t),
in [mm]
Room Temperature
Cryogenic LO
2
Cryogenic LH
2
Min., ksi [MPa]
Avg., ksi [MPa]
Min., ksi [MPa]
Min., ksi [MPa]
2014/2219
T6/T8X
≤ 0.25 [6]
46 [317]
48 [331]
57.6 [397]
62.4 [430]
2195
T8M4
0.25 < t ≤ 0.5 [6.4 < t ≤ 12.7]
57 [393]
59 [407]
71 [490]
82.6 [570]
2219/2219
T87
0.25 < t ≤ 0.5 [6.4 < t ≤ 12.7]
48 [331]
50 [345]
55.2 [381]
60 [414]
2195/2219
T8M4/T87
0.320 < t ≤ 0.65 [8.1 < t ≤ 16.5]
46 [317]
48 [331]
55.2 [381]
64.4 [444]
2219/2195
T87/T8M4
0.320 < t ≤ 0.65 [8.1 < t ≤ 16.5]
48 [331]
50 [345]
57.6 [397]
67.2 [463]
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 42 of 92
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Table VI. Close-out FPW in FSW Process Ultimate Tensile Strength Requirements
Alloy
Base Metal
Temper
Base Metal Thickness
(t), in [mm]
Room Temperature
Cryogenic LO
2
Cryogenic LH
2
Min., ksi [MPa]
Avg., ksi [MPa]
Min., ksi [MPa]
Min., ksi [MPa]
2014/2219
1
/2219
T6/T851
2
/T8X
≤ 0.25 [6]
46 [317]
48 [331]
52.8 [364]
57.6 [397]
2195/2195
1
/2195
T8M4/T851
2
/T8M4
0.25 < T ≤ 0.320
[6.4 < T ≤ 8.1]
54 [372]
56 [386]
62 [427]
67.5 [465]
2195/2195
1
/2219
T8M4/T8M4
2
/T851,
T8X or T6
0.32 [8.1]
45 [310]
47 [324]
52 [358]
56 [386]
2219/2195
1
/2195
T8X or
T6/T851
2
/T8X
0.32 [8.1]
47 [324]
49 [338]
54 [372]
59 [408]
1
Denotes FPW material
2
Denotes FPW temper
A.6.1 In relation to the GTAW process for 2219 (Table III), butt weld ultimate tensile strength requirements for tempers that require
other postweld aging cycles shall be approved by the procuring agency.
A.6.2 Average shall be the arithmetic average of all values measured.
A.6.3 No single value shall be less than the minimum value specified.
A.7 PROCEDURE QUALIFICATION WELD STRENGTH REQUIREMENTS FOR SUPERALLOYS
A.7.1 Average shall be the arithmetic average of all values measured.
A.7.2 No single value shall be less than the minimum value specified.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 43 of 92
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Table VII. Fusion Butt Weld Ultimate Tensile Strength Requirements for Superalloys
Alloy
Base Metal
Temper
Postweld Age
Cycle
Base Metal Thickness
(t), in [mm]
Room Temperature
Min., ksi [Mpa]
Avg., ksi [MPa]
Inconel 718
STA
1
As-Welded
≤0.25 [6]
120 [827]
125 [862]
Inconel 718
STA
1
STA
1
or DA
≤0.25 [6]
170 [1172]
175 [1207]
Inconel 718
Annealed
2
As-Welded
≤0.25 [6]
100 [689]
105 [724]
Inconel 718
Annealed
2
STA
1
or DA
≤0.25 [6]
145 [1000]
150 [1034]
Inconel 625
Annealed
3
As-Welded
≤0.5 [12.5]
105 [724]
110 [758]
Haynes 188
Solution Treated
As-Welded
≤0.25 [6]
110 [758]
117 [807]
1
Annealed and aged in accordance with either standard practice, 1750 °F (954 °C), or 1950 °F (1066 °C) anneal followed by aging.
2
Annealed in accordance with either standard practice, 1750 °F (954 °C), or 1950 °F (1066 °C).
3
Annealed 1750 °F (954 °C).
Table VIII. Fusion Butt Weld Ultimate Tensile Strength Requirements for Titanium Alloys
Alloy
Base Metal
Temper
Postweld Age Cycle
Base Metal Thickness
(t), in [mm]
Room Temperature
Min., ksi [Mpa]
Avg., ksi [MPa]
Ti-6AL-4V ELI
Annealed
Stress relieved
≤ 0.25 [6]
130 [896]
138 [951]
Table IX. Fusion Butt Weld Ultimate Tensile Strength Requirements for Stainless Steel Alloys
Alloy
Base Metal
Temper
Postweld Age Cycle
Base Metal Thickness
(t), in [mm]
Room Temperature
Min., ksi [Mpa]
Avg., ksi [MPa]
304L
Annealed
As welded
≤0.5 [12.5]
65 [448]
68 [469]
316L
Annealed
As welded
≤0.5 [12.5]
67 [462]
69 [476]
321
Annealed
As welded
≤0.5 [12.5]
73 [503]
75 [517]
347
Annealed
As welded
≤0.5 [12.5]
72 [496]
74 [510]
21-6-9
Annealed
As welded
≤0.5 [12.5]
100 [689]
105 [724]
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 44 of 92
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USE
Appendix B
Weld Joint Dimensional Requirements
B.1 PURPOSE AND/OR SCOPE
The purpose of this appendix is to provide weld joint dimensional requirements.
B.2 FIT-UP REQUIREMENTS
Table X and Table XI present preweld and postweld joint fit-up requirements for various
welding processes.
Values in Table X and Table XI may be changed with approval by the responsible NASA
Technical Authority if positive margins of safety can be shown by engineering analysis or test
data.
Table X. Preweld Joint Fit-up Requirements
Process
Mismatch, in [mm]
Peaking,
degrees
Joint Gap, in [mm]
Pin Tool
Offset
Fusion
As required to meet
postweld requirements
As required to
meet postweld
requirements
N/A
N/A
EBW and LBW
10% of joint thickness
or 0.01 [0.25],
whichever is less, for
thickness up to
0.25 [6.25]
N/A
5% thickness up to 0.009
[0.22]
N/A
10% thickness over 0.009
- 0.061 [0.22 - 1.52]
10% of joint thickness
or 0.03 [0.75],
whichever is less, for
thickness greater than
0.25 [6.25]
Not to exceed 0.01 [0.25]
thickness over 0.061 - 1.49
[1.52 - 37.2]
Not to exceed 0.005 [0.12]
thickness over 1.49 [37.2]
SR-FSW
0.200< t <0.327
[5.0< t <8.3]
0.040 [1]
2
0.030 [0.76]
0.05 [1.27]
Minimum -
0.20X pin
diameter
C-FSW
0.250< t <0.650
[6.36<t<16.5]
0.020 [0.508]
3
0.040 [1]
N/A
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Table XI. Postweld Joint Fit-up Requirements
Process
Base Metals
Mismatch, in [mm]
Peaking, in [mm]
Fusion
Steels, corrosion- and
heat-resistant alloys
0.06 [1.5] or 20% of the
thinnest member, whichever
is less
5
deg maximum unless at a weld
intersection, then 2
deg for
6 [15.2] adjacent to intersection
Aluminum alloys
0.02 [0.508] for thickness of
0.2 [5.08] or less
5
deg maximum unless at a weld
intersection, then 2
deg for
6 [15.2] adjacent to intersection
For thickness greater than
0.2 [5.08], maximum 0.04
[10.16] or 10% of thinnest
member, whichever is less
Titanium alloys
0.06 [1.5] or 20% of the
thinnest member, whichever
is less for material thickness
of 0.5 [12.5] or less
5
deg maximum unless at a weld
intersection, then 2
deg for
6 [15.2] adjacent to intersection
0.120 [3.0] or 10% of
material thickness,
whichever is less, for
material thickness greater
than 0.5 [12.5]
FSW
Aluminum alloys
N/A
N/A
MSFC Technical Standard
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Appendix C
Weld Nugget Dimensional Requirements
C.1 PURPOSE AND/OR SCOPE
The purpose of this appendix is to provide weld nugget dimensional requirements for various
welding techniques and materials.
C.2 FUSION
Table XII and Figure 5 provide fusion weld nugget dimensional requirements.
Table XII. Dimensional Requirements for Butt Welds – Fusion
1
Base
Metal
Thickness,
in [mm]
d-Min.,
in [mm]
As-Welded Reinforcement
(R and R´) Minimum
Weld Width (W' and W'')
Maximum
R,
in [mm]
R´,
in [mm]
Multipass, Beveled
Joint, and Torch
Oscillated, in [mm]
Single Pass,
Square Butt,
in [mm]
Aluminum
Alloys
< 0.125 [3]
0.020
[0.508]
0.005
[0.127]
0.015
[0.381]
5t
0.375 [9.5] or
5t, whichever
is smaller
0.125 - 0.25
[3 - 6]
0.05
[1.27]
0.005
[0.127]
0.015
[0.381]
1t + 0.4 [10.2]
1t + 0.25 [6]
> 0.25 [6]
0.06
[1.524]
0.005
[0.127]
0.015
[0.381]
As required by
design
As required by
joint design
2195
0.125 - 0.25
[3 - 6]
0.05
[1.27]
0.04 [1]
0.04 [1]
1t + 0.4 [10.2]
1t + 0.25 [6]
> 0.25 [6]
0.06
[1.524]
0.04 [1]
0.04 [1]
0.75t + 0.45 [11.4]
0.5t + 0.45
[11.4]
1
Reference Figure 5
Figure 5. Aluminum Fusion Butt Weld
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C.3 ELECTRON BEAM WELDING
Figure 6 thru Figure 9 illustrate weld nugget dimensional requirements for EBW Butt Joints.
C.3.1 The weld offset shall not exceed 0.2D or 0.06 in [1.5 mm], whichever is less, where D is
the minimum required depth of fusion.
C.3.2 Offset shall be measured on the face side (beam impinging side) of the joint at a distance
of 0.15 in ±0.06 [3.8 mm ±1.5] from the edge of the fusion zone on either side of the weld.
Figure 6. EBW Butt Weld
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Figure 7. EBW Max Weld Crown and Root Widths for Penetration Depths (D) ≤ 1.6 in [41 mm]
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Figure 8. Min EBW Root Width for Penetration Depths (D) ≤ 0.2 in [5 mm]
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Figure 9. Min EBW Root Width for Penetration Depths (D) of 0.2-1.6 in [5-41 mm]
C.4 FRICTION STIR WELDING
C4.1. Geometrical requirements for FSW shall be defined in the applicable Engineering
documentation, as approved by the NASA Technical Authority.
C4.2. Reference joint thickness shall be listed on applicable Engineering documentation (i.e.
Nominal, Minimum or As-Built thickness)
Table XIII, Figure 10 and Figure 11 may be used for reference as recommended FSW nugget
dimensional characteristics.
Table XIII. Dimensional Characteristics of Aluminum Alloy Butt Welds
Process
Thickness in [mm]
Underthickness
1
C-FSW
0.188 ≤ t ≤ 1.250 in
[4.78 ≤ t ≤ 31.75]
5% below reference joint parent metal thickness.
SR-FSW
0.188 ≤ t ≤ 0.750 in
[4.78 ≤ t ≤ 19.05]
10% below reference joint parent metal thickness.
1
Underthickness maximum is cumulative from crown and root for a given side (i.e. Advancing or Retreating).
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Figure 10. C-FSW Zone
Figure 11. SR-FSW Zone
Notes:
Underthickness = t
REF
– t
MIN
t
MIN
may occur anywhere in weld joint
a. for as-welded configurations t
MIN
will likely occur at the toe of the weld in the heel
plunge region
b. for blended or re-worked configurations the thickness may be checked in re-worked
area
t
REF
defined in applicable engineering document and may vary with the program. Examples
include, but are not limited to the following definitions:
a. may be defined as nominal drawing base metal weld land thickness
b. may be defined as minimum drawing base metal weld land thickness
c. may be defined as as-built base metal weld land thickness
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C.5 TITANIUM
Table XIV and Figure 12 thru Figure 16 provides titanium weld nugget dimensional
requirements.
Table XIV. Dimensional Requirements
Thickness Nominal
in [mm]
Class A Weld
Class B Weld
0 - 0.01
[0 -0.254]
S(MAX)
X(MIN)
R(MAX)
W(MAX)
0
0
0.5t + 0.02
0.09
.05t
0
0.5t + 0.02
0.09
0.01 - 0.02
[0.254 - 0.51]
S
X
R
W
0
0
0.5t + .02
0.18
0.05t
0
0.5t + 0.02
0.18
0.02 - 0.03
[0.51 - 0.76]
S
X
R
W
0
.05t
0
0
0.3t + 0.02
0.3t + 0.02
0.18
0.18
0.03 - 0.05
[0.76 - 1.27]
S
X
R
W
0
0.05t
0
0
0.3t + 0.02
0.3t + 0.02
5.0t
5.0t
0.05 - 0.10
[1.27 - 2.54]
S
X
R
W
0
0.05t
0
0
0.4t + 0.02
0.4t + 0.02
4.0t
4.0t
0.10 [2.54]
and over
S
X
R
W
0
0.05t or 0.03
1
0.05t or 0.03
1
0
0.6t or 0.09
1
0.6t or 0.12
In accordance with Figure 12
In accordance with Figure 12
1
Whichever is less
Figure 12 contains definitions.
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Figure 12. Titanium Full-Penetration Joint Welds
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Figure 13. Titanium Butt Joint Maximum Allowable Weld Width (W) versus Thickness (t)
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Figure 14. Titanium Fillet Joint Maximum Allowable Weld Width versus Thickness
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Figure 15. Titanium Maximum Fillet Weld Size L
MIN
= thickness of the thinnest member
Figure 16. Titanium Fillet Weld Dimensions for Acute Angle and Drop Through
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C.6 SUPERALLOYS
Figure 17 thru Figure 24 provides superalloy weld nugget dimensional requirements.
Figure 17. Weld Size Requirements for Butt Welds
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Figure 18. Class A Butt Weld Fusion Zone Weld Size Limits
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Figure 19. Class B Butt Weld Fusion Zone Weld Size Limits
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Figure 20. Class C Butt Weld Fusion Zone Weld Size Limits
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Figure 21. Weld Size Requirements for T and Corner Welds
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Figure 22. Class A, T and Corner Weld Fusion Zone Weld Size Limits
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Figure 23. Class B, T and Corner Weld Fusion Zone Weld Size Limits
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Figure 24. Class C, T and Corner Weld Fusion Zone Weld Size Limits
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Appendix D
Weld Quality Requirements
D.1 PURPOSE AND/OR SCOPE
The purpose of this appendix is to provide weld accept/reject criteria requirements.
D.2 ACCEPTANCE CRITERIA
Table XV thru Table XVII and Figure 25 thru Figure 27 present weld surface acceptance criteria for various metal alloys.
Table XV. Weld Surface and Volumetric Acceptance Criteria – Aluminum Alloys
Process
Discontinuity
Class A, in [mm]
Class B, in [mm]
Class C, in [mm]
All
Cracks
None allowed
None allowed
None allowed
Overlap (cold lap)
None allowed
None allowed
None allowed
Incomplete Fusion
None allowed
None allowed
None allowed
Incomplete Penetration
None allowed
None allowed
None allowed for full-
penetration welds
Undercut, concavity, lack
of fill, suckback
None allowed where it occurs as a sharp notch or
where the depth reduces the material thickness below
drawing requirements
None allowed where it occurs as a sharp notch or where
the depth reduces the material thickness below drawing
requirements
None allowed where it
occurs as a sharp
notch or where the
depth reduces the
material thickness
below drawing
requirements
Fusion
Surface
porosity,
oxides
Butt Joints
t/3 or 0.065 [1.65], whichever is smaller
t/2 or 0.100 [2.54], whichever is smaller
N/A
Fillet Weld
S/3 or 0.050 [1.27], whichever is smaller
S/3 or 0.075 [1.9], whichever is smaller
N/A
Scattered
Sum of the areas of all individual surface
discontinuities within any 1.0 [25.4] of weld shall be
less than 1/2 the maximum discontinuity area in
Figure 25.
Sum of the areas of all individual surface discontinuities
within any 1.0 [25.4] of weld shall be less than 1/2 the
maximum discontinuity area in Figure 25.
N/A
Scattered
No more than 15 individual surface discontinuities in
any 1.0 [25.4] regardless of size are allowed.
N/A
N/A
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Process
Discontinuity
Class A, in [mm]
Class B, in [mm]
Class C, in [mm]
Fusion
Surface
porosity,
oxides
Linear
Three or more in a line are rejectable if the line
extends more than 0.25 [6.35] and the discontinuities
occupy more than 50% of the length of line.
Three or more in a line are rejectable if the line extends
more than 0.50 [12.7] and the discontinuities occupy
more than 50% of the length of line.
N/A
Sharp
Rejectable if maximum dimension exceeds 0.100
[2.54].
Rejectable if maximum dimension exceeds 0.100 [2.54].
N/A
Cluster
Three or more discontinuities each measuring 0.01
[0.254] or more, touching or falling within a 0.25
[6.35] diameter circle, shall be classified as a cluster
when the sum of their maximum dimension exceeds
t/3 or 0.065 [1.65] for butt welds and S/3 or 0.05
[1.27] for fillet, whichever is smaller. Two clusters
are rejectable if separated by less than butt weld
thickness (t) or less than specified fillet size (S).
Three or more discontinuities each measuring 0.02
[0.508] or more, touching or falling within a 0.25 [6.35]
diameter circle, shall be classified as a cluster when the
sum of their dimensions exceeds t/3 or 0.065 [1.65] for
butt welds, and S/3 or 0.050 [1.27] for fillet welds,
whichever is smaller for each weld. Two clusters are
rejectable if separated by less than half the butt weld
thickness (t/2) or less than half the specified fillet size
(S/2).
N/A
Volumetric
voids,
inclusions
Close
Spacing
Discontinuities that appear overlapping, touching, or
connected viewed normal to the weld surface for butt
welds and at an optimum angle for fillet welds shall
be treated as a single discontinuity. The spacing
requirement is not applicable to discontinuities
connected to the root of the weld for fillet welds.
Discontinuities that appear overlapping, touching, or
connected viewed normal to the weld surface for butt
welds and at an optimum angle for fillet welds shall be
treated as a single discontinuity. The spacing
requirement is not applicable to discontinuities
connected to the root of the weld for fillet welds.
N/A
Maximum
Size
The maximum dimension of an individual internal
discontinuity as viewed normal to the weld surface
for butt welds and at an optimum angle for fillet
welds shall not exceed the values obtained from
Figure 26.
The maximum dimension of an individual internal
discontinuity as viewed normal to the weld surface for
butt welds and at an optimum angle for fillet welds shall
not exceed the value obtained in Figure 26.
N/A
Scattered
Scattered internal discontinuities not exceeding
individual discontinuity limitations shall be evaluated
for accumulative area per 1 [25.4] of weld. Area
calculations shall be based on best fit circle or
rectangle. Butt and fillet welds, including
discontinuities connected to the root of fillet welds,
shall conform to the requirements of Figure 26.
Scattered internal discontinuities not exceeding the
individual discontinuity limitations shall be evaluated
for accumulative area per 1 [25.4] of weld. In addition,
all discontinuities connected to the root of a fillet weld
shall be included in the accumulative area. Area
calculations shall be based on the best fit circle or
rectangle. The area in any 1 [25.4] of weld shall not
exceed the value obtained from Figure 26.
N/A
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Process
Discontinuity
Class A, in [mm]
Class B, in [mm]
Class C, in [mm]
Fusion
Volumetric
voids,
inclusions
Scattered -
butt welds
Any 1 [25.4] of weld with maximum allowable area
of Figure 26 shall have no more than one-half the
maximum allowable area in each adjacent 1 [25.4] of
weld.
N/A
N/A
Scattered -
butt weld
intersections
That 6 [152], i.e., 3 [76] to each side of the
intersection, of weld intersection by another weld
shall have the maximum allowable area of Figure 26
reduced by 1/3.
N/A
N/A
Scattered
There shall be no more than 15 discontinuities in any
1 [25.4] of weld regardless of size or cumulative area
loss.
N/A
N/A
Linear
Three or more discontinuities, which are in line, are
unacceptable if the line extends more than 0.25
[6.35] and the discontinuities occupy more than 50%
of the length of the line. This requirement is not
applicable to discontinuities connected to the root of
fillet welds.
Three or more discontinuities, which are in a line, are
unacceptable if the line extends more than 0.5 [12.7] and
the discontinuities occupy more than 50% of the length
of the line. This requirement is not applicable to
discontinuities connected to the root of fillet welds.
N/A
Sharp
Any discontinuity that appears to have a crack-like
extension shall be cause for rejection. If the longest
accumulative dimension is more than 5X the width at
the smallest dimension, the indication shall be cause
for rejection. This requirement is not applicable to
discontinuities connected to the root of fillet welds.
Any discontinuity that appears to have a crack-like
extension shall be cause for rejection. If the longest
accumulative dimension is more than 7X the width at
the smallest dimension, the discontinuity shall be cause
for rejection. This requirement is not applicable to
discontinuities connected to the root of fillet welds.
N/A
Cluster
Three or more discontinuities, each measuring 0.010
[0.254] or more, touching or falling within a 0.25
[6.35] diameter circle, shall be classified as a cluster
when the sum of their dimensions exceeds the
allowable maximum dimension of an individual
discontinuity in Figure 26. For butt welds, two
clusters are unacceptable if separated by less than the
material thickness. For fillet welds, two clusters are
unacceptable if separated by less than the specified
fillet weld size (S/2). This requirement is not
applicable to discontinuities connected to the root of
the fillet welds.
Three or more discontinuities, each measuring 0.02
[0.508] or more, touching or falling within a 0.25 [6.35]
diameter circle, shall be classified as a cluster when the
sum of their maximum dimensions exceeds the
allowable maximum dimension of an individual
discontinuity in Figure 26. For butt welds, two clusters
are unacceptable if separated by less than half the
material thickness (t/2). For fillet welds, two clusters
are unacceptable if separated by less than half the
specified fillet size (S/2). This requirement is not
applicable to discontinuities connected to the root of
fillet welds.
N/A
MSFC Technical Standard
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Process
Discontinuity
Class A, in [mm]
Class B, in [mm]
Class C, in [mm]
Friction
Surface
Galling or tears on the surface of the weld visually
indicated by open surface features or blisters shall be
cause for rejection.
Galling or tears on the surface of the weld visually
indicated by open surface features or blisters shall be
cause for rejection.
N/A
Volumetric voids,
inclusions
Wormholes/voids/lack of adequate forgings shall be
cause for rejection.
Wormholes/voids/lack of adequate forging shall be
cause for rejection.
N/A
Electron
Beam
Undercut and concavity
Sharp crevice at root
Thin weldment below minimum drawing requirements - rejectable
Exceed a depth of 0.05t or 0.040 [1], whichever is less - rejectable
Exceed a width of 0.25t or 0.08 [2], whichever is less - rejectable
Exceed a length of 0.5 [12.7] for any single indication or a total of 1.5 [38] in any 6 [152] length - rejectable
Volumetric
porosity/inclusions
Accept per SAE AMS 2680
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Figure 25. External Discontinuities for Aluminum Alloys
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Figure 26. Internal Defects for Aluminum Alloys
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Table XVI. Surface and Volumetric Acceptance Criteria – Steels, Heat Resistant Alloys
Process
Discontinuity
Class A, in [mm]
Class B, in [mm]
Class C, in [mm]
All
Cracks
None allowed
None allowed
None allowed
Overlap (cold lap)
None allowed
None allowed
None allowed
Incomplete fusion
None allowed
None allowed
None allowed
Incomplete
penetration
None allowed
None allowed
None allowed for full-
penetration welds
Undercut,
concavity, lack of
fill, suckback
None allowed where it
occurs as a sharp notch
or where the depth
reduces the material
thickness below
drawing requirements
None allowed where it
occurs as a sharp notch
or where the depth
reduces the material
thickness below
drawing requirements
None allowed where it
occurs as a sharp notch
or where the depth
reduces the material
thickness below
drawing requirements
Fusion
Surface porosity
and inclusions
NAS 1514 Class I
NAS 1514 Class II
NAS 1514 Class III
Internal quality
NAS 1514 Class I
NAS 1514 Class II
NAS 1514 Class III
Electron Beam
Undercut and
concavity
Sharp crevice at root - reject
Thin weldment below minimum drawing requirements - reject
Exceed a depth of 0.05t or 0.040 [1], whichever is less - reject
Exceed a width of 0.25t or 0.080 [2], whichever is less - reject
Exceed a length of 0.5 [12.7] for any single indication or a total of 1.5
[38.1] in any 6 [152] length - reject
Porosity
See Figure 27.
Pore clusters
Clusters of two or
more pores are
acceptable, provided
the clusters may be
enclosed within a
circle of diameter
equal to or less than
the maximum pore
size allowed.
Clusters of two or
more pores are
acceptable, provided
the clusters may be
enclosed within a
circle of diameter
equal to or less than
the maximum pore size
allowed.
N/A
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Figure 27. EBW Porosity Acceptance Criteria for Steels, Heat Resistant
Table XVII. Weld Surface and Volumetric Acceptance Criteria – Titanium Alloys
Discontinuity
Class A
Class B
Class C
Cracks
None allowed
None allowed
None allowed
Overlap (cold lap)
None allowed
None allowed
None allowed
Incomplete fusion
None allowed
None allowed
None allowed
Incomplete penetration
None allowed
None allowed
None allowed
Porosity
NAS 1514 Class I
NAS 1514 Class II
NAS 1514 Class III
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Appendix E
Weld Procedure Specification Information
E.1 PURPOSE AND/OR SCOPE
The purpose of this appendix is to provide guidance. It contains information of a general or
explanatory nature but does not contain requirements.
E.2 RECOMMENDED PARAMETERS TO BE RECORDED IN WPS
Table XVIII recommends parameters to be recorded in a WPS and contains information of a
general or explanatory nature but does not contain requirements.
Table XVIII. Recommended Parameters to be Recorded in a WPS
Electron Beam
Welding
Fusion
(Automatic and
Mechanized)
Fusion
(Manual and Semi-
Automatic)
Friction Stir
Welding
Friction Plug
Welding
Base metal alloys
Base metal alloys
Base metal alloys
Base metal alloys
Base metal alloys
Base metal
thickness(es)
Base metal
thickness(es)
Base metal
thickness(es)
Base metal
thickness
Base metal
thickness(es)
Base metal heat treat
condition(s)
Base metal heat treat
condition(s)
Base metal heat treat
condition(s)
Base metal heat treat
condition(s)
Base metal heat treat
condition(s)
Joint configuration
Joint configuration
Joint configuration
Joint configuration
Joint configuration
Weld position
Weld position
Weld position
Penetration ligament
Weld position
Start-up parameters
Start-up parameters
Start-up parameters
Start-up parameters
Start-up parameters
Surface preparation
at weld joint
Joint preparation
method
Joint preparation
method
Joint preparation
method
Joint preparation
method
Tacking passes and
parameters
Tacking passes and
parameters
Tacking passes and
parameters
Tacking passes and
parameters
Backing plate/button
drawing number
Preweld cleaning
procedure or
specification or both
Preweld cleaning
procedure or
specification or both
Preweld cleaning
procedure or
specification or both
Preweld cleaning
procedure or
specification or both
Preweld cleaning
procedure or
specification or both
Procedure
qualification number
Procedure
qualification number
Procedure
qualification number
Procedure
qualification number
Procedure
qualification number
Filler metal type and
specification
Wire alloy and size
Weld filler metal
type and diameter
Plunge Load
Plug design
High voltage (±5%)
Wire speed (ipm)
Wire speed (ipm)
Travel speed
Travel speed
Beam current (±5%)
Weld type
Weld process
Spindle speed
Spindle speed
Welding Speed ipm
[mm/sec] (±5%)
Travel speed
Tungsten type, size,
and configuration
Joint designation
Forge time
Filler wire feed speed
(±10%)
Tungsten size, type,
configuration, and
tolerances
Target values for
amps, volts, and
travel speed
Pin tool part
number, material, or
drawing number
Forge load
Focusing current
(±5%)
Tungsten extension
Tungsten extension
Torque range
Heating load
Number of passes
and sequence
Number of passes
and sequence
Number of passes
and sequence
Heel plunge
Heating
displacement
Welding vacuum
pressure (torr)
Welding current
Current polarity
Indicate force or
position control
Plug alloy
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Electron Beam
Welding
Fusion
(Automatic and
Mechanized)
Fusion
(Manual and Semi-
Automatic)
Friction Stir
Welding
Friction Plug
Welding
Sketch of setup,
including all angles
(±0.5 deg), MAX gap
Welding current
type
Range on power
supply
Shoulder part
number, material, or
drawing number
Computer program
name/number
EBW certification
number
Times for straight
and reverse current
Power supply
Pin length
Operator and ID
stamp
Arc voltage
Maximum gap
allowance
Root face or surface
coating
Gun to work distance
±0.125 in [±3 mm]
Power supply
ampere range
Shield gas type and
flow rate
Root opening (or
gap)
Cathode to anode
spacer
Power supply
Backside shielding
gas type and flow
rate
Weld fixture
drawing number
Beam deflection
____on_____off
Power supply mode
selection
Shield cup/nozzle
size
Weld schedule
Computer program
name/number
Shield gas type and
flow rate
Torch
Centerline offset
Nugget dimensions in
accordance with
Figure 6
Backside shielding
gas type and flow
rate
Torch lead angle
Traverse load
Dimensions of
starting weld tab and
run off tab plates
Shield cup/nozzle
size
Lead angle
Termination
parameters
Computer program
name/number
Axial load
Torch lead angle
MAX plunge force
Start slope current
and time
MAX plunge speed
Tail slope current
and time
Specific tapered
thicknesses, if a
tapered thickness is
being welded
Oscillation dwell,
width, and speed
Machine model and
serial numbers
Torch
Grain direction
Termination
parameters
Dwell time
Direction of tool
rotation
Anvil material
Clamp pressure
Termination
parameters
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 75 of 92
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Appendix F
Recommended Weld Filler Metals
F.1 PURPOSE AND/OR SCOPE
This purpose of this appendix is to provide guidance. It contains information of a general or
explanatory nature but does not contain requirements.
F.2 TABLES
Table XIX thru Table XXIV present recommended filler alloys for various metal combinations.
Table XIX. Filler Alloys Recommended for Aluminum Alloys and Combinations
Base Alloy
2014
2219
2195
5052
6061
1
5456
2014
4043, 2319
4043
2219
2319, 4043
2319
4043, 2319
4043
2195
4043, 2319
4043
5052
5356
4043
6061
1
4043
4043
4043
4043
5456
4043, 5356
4043, 5356
5356, 5556
4043, 5356
5356, 5556
1
Unless specified otherwise, filler metal shall be used when fusion welding 6061.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Table XX. Filler Alloys Recommended for Carbon and Low Alloy Steels and Combinations
Base Alloy
Mild
Steels
Construction
Steels
4130
4135, 4140
4335, 4340
T1
9Ni 4Co
18-7 Maraging
Steel (250)
Mild Steels
GA65
NAX 9115
Vac Melt
17-22AS
Vac Melt
17-22AS
Vac Melt
17-22AS,
GA65
Vac Melt
17-22AS,
GA65
Construction
Steels
NAX 9115
Vac Melt
17-22AS
Vac Melt
17-22AS
Vac Melt
17-22AS,
GA65
Vac Melt
17-22AS,
GA65
4130
Vac Melt
17-22AS
Vac Melt
17-22AS
Vac Melt
17-22AS
Vac Melt
17-22AS
4135, 4140
Vac Melt
17-22AS
Vac Melt
17-22AS
Vac Melt
17-22AS
4335, 4340
Vac Melt
17-22AS
Vac Melt
17-22AS
9Ni 4Co
HP 9-4-.2
18-7 Maraging
Steel (250)
18-7 Maraging
Steel
Hastelloy C
Hastelloy W
304, 310, 321, 347
Inconel 82
Inconel 82
Inconel 92
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Table XXI. Filler Alloys Recommended for Stainless Steels and Combinations
Base Alloy
304, 304L
310
316,
316L
321, 347
410
430
19-9DL,19-
9DX
17-4 PH
17-7 PH
304 , 304L
308L
308L
316L
308L
349
Hastelloy W
Hastelloy W
310
310
310
310
349
Hastelloy W
Hastelloy W
316, 316L
316L
347
Inconel 92
Hastelloy W
Hastelloy W
321, 347
321, 347
Hastelloy W
349
Hastelloy W
Hastelloy W
410
410
430
430
430
19-9DL, 19-9DX
349
Hastelloy W
Hastelloy W
17-4 PH
17-4 PH
17-7 PH
17-7 PH
17-7 PH
16-25-6
21-6-9
29-20 Cb
29-9
AM350
AM355
A-286
Haynes 21
Haynes 188
308L,
Haynes 188
308L,
Haynes 188
Incoloy 903
Cartech CTX-1
Invar 36
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Table XXI. Filler Alloys Recommended for Stainless Steels and Combinations (continued)
Base Alloy
16-25-6
21-6-9
29-20 Cb
29-9
AM350
AM355
A-286
Incoloy 903
Cartech CTX-1
Invar 36
304, 304L
Hastelloy W
308L 36%
Nickel
29.20 Cb
AM350
AM355
Hastelloy W
310
Hastelloy W
308L
29.20 Cb
AM350
AM355
Hastelloy W
316, 316L
Hastelloy W
308L
29.20 Cb
Inconel
92
Inconel 92
Hastelloy W
321, 347
Hastelloy W
308L 36%
Nickel
29.20 Cb
AM350
AM355
Hastelloy W
Hastelloy W
410
430
19-9DL, 19-9DX
17-7 PH
16-25-6
349
312
21-6-9
ARMCO
21-6-9
Hastelloy W
29-20 Cb
29.20 Cb
AM355
AM355
29-9
312
AM350
AM350
AM350
AM355
AM355
A-286
A-286
Haynes 21
Hastelloy W
Haynes 188
Haynes
188
Incoloy 903
Cartech CTX-1
Incoloy 903
Invar 36
36% Nickel
Hastelloy W
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Table XXII. Filler Alloys Recommended for Nickel- and Cobalt-Base Alloys and Combinations
Base Alloy
Ni200
Ni270
ED
Nickel
Monel
400
K-Monel
500
Inconel 600
Inconel X 750
Inconel 718
Inconel 625
Hastelloy B
Hastelloy C
Hastelloy X
Ni200
Ni270
Nickel 61
Nickel
61
Nickel 61
Nickel 61
Hastelloy W
Hastelloy W
Hastelloy W
ED Nickel
Nickel 61
Nickel
61
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Monel 400
Monel 60
Monel 60
Inconel 600
Inconel 82
Hastelloy W
Hastelloy W
Hastelloy
W
Hastelloy W
Hastelloy W
Hastelloy W
Inconel X 750
Inconel 69
Inconel 718,
Hastelloy W
Hastelloy
W
Hastelloy W
Hastelloy W
Hastelloy W
Inconel 718
Inconel 718
Inconel 625
Hastelloy W
Hastelloy W
Hastelloy W
Inconel 625
Inconel 625
Inconel 625
Inconel 625
Inconel 625
Hastelloy B
Hastelloy B
Hastelloy W
Hastelloy W
Hastelloy C
Hastelloy C
Hastelloy W
Hastelloy X
Hastelloy X
Haynes 21
Haynes 25 L-605
Haynes 188
Haynes 230
Rene' 41
Incoloy 800
Incoloy 88
4130, 4140
Inconel 92
Hastelloy W
Hastelloy W
4340
Inconel 92
304L, 347, 321,
316L , 310
Inconel 92
Inconel 625,
Hastelloy W
Hastelloy W
Inconel 625,
Hastelloy W
Inconel 625
Hastelloy W
Hastelloy W
Hastelloy W
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 80 of 92
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Table XXII. Filler Alloys Recommended for Nickel- and Cobalt-Base Alloys and Combinations (continued)
Base Alloy
Haynes 21
Haynes 25
L-605
Haynes 188
Haynes 230
Rene' 41
Incoloy
800
Incoloy 88
Incoloy 903
Cartech CTX-1
21-6-9
Ni200. Ni270
Hastelloy W
Hastelloy W
Hastelloy W
ED Nickel
Nickel 61
Nickel 61
Nickel 61
Nickel 61
Monel 400
Inconel 600
Hastelloy W
Hastelloy W
Hastelloy W
Hastelloy W
Inconel X 750
Hastelloy W
Hastelloy W
Hastelloy W
Inconel 718
Hastelloy W
Hastelloy W
Haynes 188
Incoloy 88
Incoloy 88
Incoloy 903
Inconel 625,
Incoloy 88
Inconel 625
Inconel 625
Inconel 625
Inconel 625
Inconel 625
Inconel 625,
Incoloy 88
Inconel 625
Inconel 625,
Incoloy 88
Hastelloy B
Hastelloy W
Hastelloy W
Haynes 188
Hastelloy C
Hastelloy C
Hastelloy W
Haynes 188
Hastelloy X
Hastelloy W
Hastelloy W
Hastelloy W
Haynes 21
Haynes 25
Haynes 25
Haynes 188
Haynes 25 L-605
Haynes 25
Haynes 188
Haynes 188
Haynes 188
Haynes 188
Haynes 188
Haynes 188
Haynes 230
Haynes 230
Rene' 41
Hastelloy W,
Rene' 41
Incoloy 800
Incoloy 88
Incoloy 88
Incoloy 88,
Incoloy 903,
Haynes 188
4130, 4140
4340
304L, 347, 321,
316L, 310
Hastelloy W
Hastelloy W
Haynes 188
Hastelloy W
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Table XXIII. Filler Alloys Recommended for Copper Alloys and Combinations
Base Alloy
OFCH Copper
Deoxidized Copper
Amzirc
Narloy A
Narloy Z
OFCH Copper
Deoxidized
Copper
Deoxidized Copper
Silicon Bronze
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Amzirc
Deoxidized Copper
Deoxidized Copper
Deoxidized Copper
Narloy A
Deoxidized Copper
Deoxidized Copper
Narloy Z
Deoxidized Copper
Note: Deoxidized copper is used for maximum thermal conductivity. It has low strength.
Table XXIV. Filler Alloys Recommended for Titanium Alloys and Combinations
Base Alloy
CP Titanium
5Al-2.5Sn
5Al-2.5Sn ELI
6Al-4V
6Al-4V ELI
3Al-2.5V
CP Titanium
CP Titanium
5Al-2.5Sn
CP Titanium
Ti 5Al-2.5Sn, Ti 5Al-2.5Sn ELI
5Al-2.5Sn ELI
CP Titanium
Ti 5Al-2.5Sn,
Ti 5AL-2.5Sn ELI
Ti 5Al-2.5Sn ELI
6Al-4V
Ti 6Al-4V, Ti
6Al-4V ELI
Ti 6Al-4V,
Ti 6Al-4V ELI
Ti 5Al-2.5Sn ELI
Ti6 Al-4V,
Ti 6Al-4V ELI
Ti 6Al-4V,
Ti 6Al-4V ELI
Ti 6Al-4V, Ti 6Al-4V ELI
6Al-4V ELI
Ti 6Al-4V ELI
Ti 6Al-4V ELI
Ti 6Al-4V,
Ti 6Al-4V ELI
Ti 6Al-4V ELI
3Al-2.5V
Ti 6Al-4V,
Ti 6Al-4V ELI,
Ti 3Al- 2.5V
Ti 6Al-4V,
Ti 6Al-4V ELI, Ti 3Al-2.5V
Ti 3Al-2.5V
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 82 of 92
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Appendix G
Preweld and Postweld Cleaning Methods
G.1 PURPOSE AND/OR SCOPE
The purpose of this appendix is to provide preweld and postweld requirements.
G.2 PREWELD AND POSTWELD CLEANING METHODS
Table XXV lists preweld and postweld cleaning methods for various alloys.
Table XXV. Acceptable Preweld and Postweld Cleaning Methods
Method
Alloy
Degrease
by Alkaline
Wash
Chemical
Descale
Chemical
Deoxidize
Hand Scrape
/ Draw File
Hand Grind
/ Sand
Hand Wire
Brush
1
Scotch-
Brite
TM
Abrasion
2
Hand
Solvent
Wipe
Aluminum
Alloys
X
X
X
X
X
X
X
Copper
Alloys
X
X
X
X
X
X
X
Nickel-
Based Alloys
X
X
X
X
X
X
Chromium-
Based
Alloys
3
Stainless
Steels
X
X
X
X
X
X
X
Titanium
Alloys
4
X
X
X
X
X
X
Carbon
Steels
X
X
X
X
X
X
1
Stainless steel wire brushes only.
2
Use only coated abrasive and Scotch-Brite™ Roloc™ products.
3
Do not use chlorinated solvents.
4
Do not use chlorinated or halogenated solvents.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 83 of 92
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Appendix H
Reference Documents
H.1 PURPOSE AND/OR SCOPE
This purpose of this appendix is to list the specifications used in the development of this process
specification. This appendix contains information of a general or explanatory nature but does not
contain requirements.
H.2 GOVERNMENT DOCUMENTS
NASA George C. Marshall Space Flight Center
MPR 8730.5
Metrology and Calibration
MSFC-SPEC-504C
Specification: Welding, Aluminum Alloys
MSFC-SPEC-560A
The Fusion Welding of Steels, Corrosion and Heat Resistant Alloys
MSFC-SPEC-766
Fusion Welding Titanium and Titanium Alloys
MWI 3410.5
Personnel Certification Program for Skills
Military
MIL-STD-961
Defense and Program-Unique Specifications Format and Context
H.3 NON-GOVERNMENT DOCUMENTS
AWS
AWS C6.2
Specification for Friction Welding of Metals
AWS D17.1
Specification for Fusion Welding for Aerospace Applications
AWS D17.2
Specification for Resistance Welding for Aerospace Applications
AWS D17.3
Specification for Friction Stir Welding of Aluminum Alloys for
Aerospace Applications
NAS
NAS 976
Electron Beam Welding Machine – High Vacuum
NAS 1514
Radiographic Standard for Classification of Fusion Weld Discontinuities
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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ASME
ASME B46.1
Surface Texture Roughness, Waviness and Lay
SAE/AMS
AMS 2680
Electron-Beam Welding for Fatigue Critical Applications
AMS 2681
Electron-Beam Welding
Lockheed Martin Space Systems Company, Michoud Operations
STP 5511F
Friction Stir Welding (FSW) of Longitudinal Barrel Welds
STP 5507P
Fusion Welding of 2195 Aluminum-Lithium Alloy
STP 5508W
Plasma Arc (VPPA) Welding of 2195 Aluminum-Lithium Alloy
STP 5506L
Plasma Arc (VPPA) Welding of 2219 Aluminum
STP 5509N
Soft Plasma Arc Welding (SPAW) of 2195 Aluminum-Lithium Alloy
STP 5501T
Fusion Welding of 2219 Aluminum
STP 5510A
Friction Plug Weld (FPW) Repair
Aerojet Rocketdyne
RL10011
Fusion Welding for SSME; Process and Quality Requirements
RA1607-071 C
Requirements of Electron Beam Welding, SSME
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
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Appendix I
Acronyms and Definitions
I.1 ACRONYMS / ABBREVIATIONS
This purpose of this appendix is to list the acronyms, abbreviations and definitions used in this
process specification. This appendix contains information of a general or explanatory nature but
does not contain requirements.
Acronyms
AMS
Aerospace Material Specification
ASTM
American Society for Testing and Materials, “ASTM, International”
AWS
American Welding Society
Btu
British thermal unit
C-FSW
Conventional-Friction Stir Welding
CO
2
Carbon Dioxide
DA
Direct Aged
DOP
Depth of Penetration
EBW
Electron Beam Welding
ELI
Extra Low Interstitial
FPW
Friction Plug Welding
FPPW
Friction Pull Plug Welding
FSW
Friction Stir Weld, Friction Stir Welding
FusPW
Fusion Plug Welding
GTAW
Gas Tungsten Arc Welding
HDBK
Handbook
LBW
Laser Beam Welding
LH
2
Liquid Hydrogen
LO
2
(LOX)
Liquid Oxygen
LOP
Lack of Penetration
MIL
Military
MPCV
Multi-purpose crew vehicle
MPR
Marshall Procedural Requirements
MRB
Material Review Board
MSFC
Marshall Space Flight Center
MUA
Materials Usage Agreement
N/A
Not Applicable
NAS
National Aerospace Standards
NASA
National Aeronautics and Space Administration
NDE
Nondestructive Examination
NIST
National Institute of Standards and Technology
NPR
NASA Procedural Requirements
PAW
Plasma Arc Welding
POD
Probability of Detection
PQR
Procedure Qualification Record
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 86 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
PRF
Performance (Specification)
RPM
Revolutions per Minute
RPT
Retractable Pin Tool
SAE
Society of Automotive Engineers, International
SHE
Safety, Health, And Environmental
SI
System International or metric system of measurement
SMA
Safety and Mission Assurance
SPAW
Soft Plasma Arc Welding
SR-FSW
Self Reacting-Friction Stir Welding
SSE
System Safety Engineering
SSME
Space Shuttle Main Engine
STA
Solution Treated Aged
STD
Standard
TMAZ
Thermo-Mechanically Affected Zone
USP
United States Pharmacopeia
VPPA
Variable Polarity Plasma Arc
WCWJ
Worst Case Weld Joint
WPQ
Welder Performance Qualification
WPS
Weld Procedure Specification
Symbols
R
Reinforcement (Crown)
R'
Reinforcement (Root)
S
weld bead concavity
t
thickness of thinner joint member
T
thickness of thicker joint member
W'
maximum weld width (crown)
W''
maximum weld width (root)
I.2 DEFINITIONS
I.2.1 General Welding Definitions.
Unless otherwise defined in this process specification, welding terms, definitions, and symbols
may conform to AWS A2.4 and AWS A3.0. For additional definitions reference AWS A3.0.
2-for-1 Replacement: The practice of replacing a procedure qualification panel that does not meet
specification requirements with two panels welded with identical parameters; this practice is
only used when the original panel failed the criteria because of a processing error not
associated with the weld parameters.
Anomaly: A deviation or irregularity.
Certified: Describing a welder (operator) or inspector who passes qualification tests based on
requirements established in this process specification or term describing a weld procedure that
passes qualification tests based on requirements established in this process specification.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 87 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
Chill Bar: A steel, aluminum, or copper bar that limits distortion by limiting the heat flow from a
weld joint.
Concave Root Surface: A weld root with penetration not extending beyond the thickness of the
base metal; sometimes referred to as “suckback.”
Confidence Panel/Weld: A full-scale, high-fidelity weld made in production tooling with
procedures and parameters intended for flight hardware; can be nondestructively and
destructively tested to validate the production weld procedure.
Critical Defect: A defect that adversely affects the weld properties, causing the weld not to
perform as designed, resulting in failure of the weld joint.
Cross-Slide: Travel perpendicular to the weld direction along the surface of the hardware.
Deburred: Having had the thin ridge or area of roughness produced in cutting or shaping metal
removed.
Degaussed: Made effectively nonmagnetic by means of electrical coils carrying currents that
neutralize the magnetism of a metal object.
Essential Variables: Weld process parameters that influence directly the weld process and resulting
weld properties; examples include but are not limited to heat input, travel speed, torch setup,
pin tool configuration.
Fail Safe: A condition where a redundant load path exists within a part (or hardware), so that after
loss of any single individual load path, the remaining load path(s) have sufficient structural
capability to withstand the redistributed loads, and the loss of the load path will not cause a
catastrophic hazard.
Heat Input: Quantity of energy introduced per unit length of weld from a traveling heat source,
expressed in British thermal units per inch (Btu/in) [joules per millimeter (J/mm)]. Computed
as the ratio of the total input power of the heat source in watts (W) (Btu/second (sec)) to the
travel velocity in inches per second (in/sec) or millimeters per second (mm/sec).
Heat-Sensitive Alloys: Alloys that require mechanical working, precipitation strengthening, or
other metallurgical mechanisms to obtain their rated strength, if exposure to the heat input
from the welding process reduces or eliminates this strengthening mechanism in proximity of
the weld.
In-Process Correction: Action taken by a welder to complete a process before submittal to
inspection.
Incomplete Joint Penetration: A weld depth (extending from its face into the joint, exclusive of
reinforcement) that is less than the joint thickness.
Lack of Fill: A weld face surface not extending beyond the thickness of the base metal.
Material Review Board (MRB): A cross-functional group that reviews production or purchased
items on hold because of nonconformance or usability concerns and that determines their
disposition, which may include repair, rework, scrap, or return to the vendor.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 88 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
Material Thickness: The minimum material thickness of a joint member in accordance with
drawing tolerance; the thinner of the joint members with different thicknesses is designated "t."
NASA Technical Authority: An individual or group authorized by the contracting agency to
address technical matters and who is responsible for the interpretations and implementations of
the requirements set forth in this specification.
Nonstructural Weld: A non-load-bearing weld.
Pathfinder: High-fidelity demonstration weld before first production article; last item to be welded
before first production article.
Peaking: The angular distortion of the components resulting from welding; calculated as the angle
resulting from the intersection of tangents taken from the surface of the two components being
welded.
Peening: The surface working of metal by means of mechanical, thermal, or acoustic methods.
Most commonly accomplished through repeated blows of impelled shot or a round-nose tool.
Planishing: Mechanical working of weld metal by rolling in a mill or through a rapid succession of
blows delivered by highly polished dies or hammers.
Pressure Vessel: A container designed primarily for pressurized storage of gases or liquids and
that also performs any of the following:
Contains stored energy of 19,307 J (14,240 ft-lb) or greater based on adiabatic expansion
of a perfect gas.
Stores a gas that will experience an MDP greater than 690 kPa (100 psia).
Contains a gas or liquid in excess of 103 kPa (15 psia) that will create a catastrophic
hazard if released.
Pressurized Component: A line, fitting, valve, regulator, etc., that is part of a pressurized system
intended primarily to sustain a fluid pressure and fluid transfer. Any piece of hardware that is
not a pressure vessel or a pressurized fluid container but is pressurized via a pressurization
system.
Pressurized Structure: A hardware item designed to carry both internal pressure and vehicle
structural loads.
Proficiency Demonstration: Demonstration of a welder’s or welding operator’s ability to produce
welds meeting prescribed standards.
Qualified: A term describing a welder (operator) who has demonstrated adequacy to meet
prescribed requirements or describing a procedure that has demonstrated adequacy to meet
prescribed requirements.
Qualified Inspector: A certified individual with the responsibility and ability to judge the quality of
the welded specimens in relation to a written specification.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 89 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
Quantitative Nondestructive Examination (NDE): Examination of parts for flaws using established
and standardized inspection techniques that are harmless to hardware, such as radiography,
penetrant, ultrasonic, magnetic particle, and eddy current. The flaw detection capability of the
inspection technique is statistically based; generally with a 90% POD at a 95% confidence
level.
Repair: A procedure that makes a nonconforming item acceptable for use. The purpose of the
repair is to reduce the effect of the nonconformance. Repair is distinguished from rework in
that the characteristics after repair still do not completely conform to the applicable drawings,
specifications, or contract requirements. Nonstandard repair procedures are authorized by
MRB action for use on a one-time basis only. All repairs require MRB approval before
implementation.
Rework: A procedure applied to a nonconforming item that completely eliminates the
nonconformance and results in a characteristic that conforms completely to the drawings,
specifications, or contract requirements.
Sound Metal: Weld metal that is free from defects or flaws.
Suckback: A condition in which the weld face or root surface extends below the adjacent surface
of the base metal; also called “concave root surface” or “underfill”.
Superalloy: An alloy that resists oxidation and can withstand high temperatures and stresses.
Tapered Welds: Weld joints that change in thickness along the length of the joint.
Tooling: Production machinery.
Total Porosity Index: The total amount of porosity in a single linear inch of weld. The porosity
index shall be determined by summing the sizes of all individual pores including individual
pores contained in a cluster, in that portion of weld. Pores of size less than 0.001 in shall be
deemed to be 0.001 in. For convenience, each 0.001 in increment is assigned an index number
of one (1). Thus a weld containing four pores, in a given linear inch, with sizes of 0.030 in,
0.020 in, 0.001 in and 0.0005 in, would have a total index of 30+20+1+1 = 52.
Underthickness: The minimum material thickness of the thinnest joint member per drawing
tolerance.
Weld Land: Thickened base metal at the weld joint.
Weld Zone: The weld metal fusion zone plus the heat-affected zone.
Worst Case Weld Joint: A weld panel representative of the extreme conditions of the joint fit-up
requirements. Reference Appendix B.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 90 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
I.2.2 Friction Stir Welding (FSW) Definitions.
The following definitions apply specifically to the FSW process, illustrated in Figure 28 and
Figure 29:
Figure 28. Conventional-Friction Stir Welding Process
Figure 29. Self Reacting-Friction Stir Welding Process
Advancing Side: The side of the FS weld on which the local tangential velocity of the tool and the
travel (translational) velocity of the tool are in the same direction; for dissimilar metal
combinations, the joint designation follows the naming convention of advancing/retreating.
Anvil: A rigid surface used to keep the work piece stationary and to react the plunge force in C-FSW.
Backing Button/Plate: The anvil that reacts the load during friction plug push/pull welding.
Pin
Shoulder
Body
Work Piece
Root Side Shoulder
Crown Side Shoulder
Pin
Root Shoulder
Position and Force
Tool Holder
(attached to Spindle)
Spindle/Crown Shoulder
Position and Force
(Spindle Travel)
Travel Rate
Pin Tool
Rotation
Retractable
Pin Tool (RPT)
Shaft
SR
-FS Weld
Nut
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 91 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
Centerline Offset: The distance from the theoretical center that the pin tool is offset toward either the
advancing or retreating side.
Conventional-Friction Stir Welding (C-FSW): FSW in which the load is reacted by an anvil, as
shown in Figure 28.
Forge Load: A compressive load applied to the weld during friction stir welding.
Forge Time: The time during which the forge load is applied.
Friction Plug Welding: A solid-state weld process made in a circular hole, commonly used to close-
out a SR-FSW termination hole.
Gouge: A depression or groove on the surface of the metal in which some of the metal has been
removed; similar to a scratch but usually larger and wider with a flat or concave bottom; may
have a sharp burr or raised metal at the terminal end.
Heating Displacement/Burn Off: Terms used in friction plug pull welding, referring to the distance
the plug is pulled through the material after initial contact with the part being welded.
Heating Load: The compressive load applied during the heating phase of friction plug welding.
Heel Plunge: The greatest distance the shoulder plunges below the surface of the material being
joined during a weld; typically measured at the trailing edge of the shoulder.
Joint Line Remnant: Discontinuity consisting of a semi-continuous layer of oxide in the weld.
Lack of Fill / Surface Lack of Fill: A condition in which the weld face surface extends below the
surface of the adjacent base metal; a continuous or intermittent surface void caused by
insufficient FSW pin tool heel plunge depth.
Leading Edge: The edge of the pin tool that is instantaneously located in the position farthest
forward along the weld in the direction of travel.
Penetration Ligament: The shortest distance between the anvil and the pin tip during a weld.
Pin (Probe): The threaded part of the tool; embedded below the surface of the workpiece.
Plunge Force: The necessary force to maintain a consistent heel plunge or penetration ligament.
Retreating Side: The side of the FSW on which the local tangential velocity of the tool and the travel
(translational) velocity of the tool are in the opposite direction.
Self Reacting-Friction Stir Welding (SR-FSW): FSW process in which the anvil is replaced by a
root side shoulder that reacts the crown shoulder load, squeezing the material between the crown
and root shoulders, as shown in Figure 29.
Scratch: A groove formed in the surface of the metal. Metal is not always removed, but raised metal
may be present on either side of the impression.
Shoulder: The part of the tool that rests directly on the surface of the workpiece.
Surface Galling: Damage that removes particles from the surface; caused by excessive pin tool
rotation.
MSFC Technical Standard
EM30
Title: Process Specification – Welding
Aerospace Hardware
Document No.: MSFC-SPEC-3679
Revision: A
Effective Date: October 22, 2018
Page 92 of 92
CHECK THE MASTER LIST – VERIFY THAT THIS IS CORRECT VERSION BEFORE USE
Surface Tearing: Minute surface cracks caused by excessive pin tool rotation.
Thickness Offset: The difference in thickness of the two parts making up the weld joint.
Tool Mark: An impression or cut in the metal that generally occurs in a distinct pattern.
Trailing Edge: The edge of the pin tool that is instantaneously located in the position farthest back
along the weld, in the direction of travel.
Traverse: To travel in the weld direction.
Traverse Load: The force necessary to push the tool along the workpiece joint during welding;
depends on the weld pitch, pin tool geometry, workpiece thickness, and material alloy being
welded.
Underthickness: The measured difference between the weld minimum thickness and the applicable
reference thickness.
Weld Flash: Material pushed outward by the tool shoulder along the edges of the shoulder contact
area. (Also occurs in FPW, inertia, and flash welding.)
