PDF Aws d172

550 N.W. LeJeune Road, Miami, FL 33126

D17.2/D17.2M

1st Edition

Prepared by theAmerican Welding Society (AWS) D17 Committee on Welding in the Aircraft and Aerospace Industry

Under the Direction of theAWS Technical Activities Committee

Approved by theAWS Board of Directors

This specification provides the general resistance welding requirements for aerospace hardware. It includes, but is notlimited to, resistance spot and resistance seam welding of aluminum, magnesium, iron, nickel, cobalt, and titanium-based alloys. There are requirements for machine and procedure qualification, production witness samples, and inspectionand acceptance criteria for aerospace hardware.

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International Standard Book Number: 978-0-87171-064-2American Welding Society

550 N.W. LeJeune Road, Miami, FL 33126© 2007 by American Welding Society

All rights reservedPrinted in the United States of America

Photocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in anyform, including mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyrightowner.

Authorization to photocopy items for internal, personal, or educational classroom use only or the internal, personal, oreducational classroom use only of specific clients is granted by the American Welding Society provided that the appropriatefee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet:<www.copyright.com>.

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All standards (codes, specifications, recommended practices, methods, classifications, and guides) of the AmericanWelding Society (AWS) are voluntary consensus standards that have been developed in accordance with the rules of theAmerican National Standards Institute (ANSI). When AWS American National Standards are either incorporated in, ormade part of, documents that are included in federal or state laws and regulations, or the regulations of other govern-mental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWSstandards must be approved by the governmental body having statutory jurisdiction before they can become a part ofthose laws and regulations. In all cases, these standards carry the full legal authority of the contract or other documentthat invokes the AWS standards. Where this contractual relationship exists, changes in or deviations from requirementsof an AWS standard must be by agreement between the contracting parties.

AWS American National Standards are developed through a consensus standards development process that bringstogether volunteers representing varied viewpoints and interests to achieve consensus. While AWS administers the processand establishes rules to promote fairness in the development of consensus, it does not independently test, evaluate, orverify the accuracy of any information or the soundness of any judgments contained in its standards.

AWS disclaims liability for any injury to persons or to property, or other damages of any nature whatsoever, whetherspecial, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use of, or relianceon this standard. AWS also makes no guaranty or warranty as to the accuracy or completeness of any informationpublished herein.

In issuing and making this standard available, AWS is neither undertaking to render professional or other services for oron behalf of any person or entity, nor is AWS undertaking to perform any duty owed by any person or entity to someoneelse. Anyone using these documents should rely on his or her own independent judgment or, as appropriate, seek theadvice of a competent professional in determining the exercise of reasonable care in any given circumstances.

This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition.

Publication of this standard does not authorize infringement of any patent or trade name. Users of this standard acceptany and all liabilities for infringement of any patent or trade name items. AWS disclaims liability for the infringement ofany patent or product trade name resulting from the use of this standard.

Finally, AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so.

On occasion, text, tables, or figures are printed incorrectly, constituting errata. Such errata, when discovered, are postedon the AWS web page (www.aws.org).

Official interpretations of any of the technical requirements of this standard may only be obtained by sending a request,in writing, to the appropriate technical committee. Such requests should be addressed to the American Welding Society,Attention: Managing Director, Technical Services Division, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex D).With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered.These opinions are offered solely as a convenience to users of this standard, and they do not constitute professionaladvice. Such opinions represent only the personal opinions of the particular individuals giving them. These individualsdo not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or interpretations ofAWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.

This standard is subject to revision at any time by the AWS D17 Committee on Welding in the Aircraft and AerospaceIndustry. It must be reviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments(recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard arerequired and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWSD17 Committee on Welding in the Aircraft and Aerospace Industry and the author of the comments will be informed ofthe Committee�s response to the comments. Guests are invited to attend all meetings of the AWS D17 Committee onWelding in the Aircraft and Aerospace Industry to express their comments verbally. Procedures for appeal of an adversedecision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. Acopy of these Rules can be obtained from the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

This page is intentionally blank.

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AWS D17 Committee on Welding in the Aircraft and Aerospace Industries

R. B. Maust, III, Chair Raytheon Integrated Defense SystemsE. C. Helder, First Vice Chair GE Aircraft Engines (Retired)

G. W. Coleman, Second Vice Chair The Boeing CompanyA. M. Alonso, Secretary American Welding Society

J. T. Amin Lockheed Martin Aeronautics CompanyR. P. Beil Northrop Grumman CorporationP. J. Cecil The Boeing CompanyW. Collier Delta Airlines Technical Operations

P. E. Daum Rolls-Royce CorporationH. S. Dilcher, III Lockheed Martin Aeronautics Company

R. J. Ding NASA�Marshall Space Flight CenterJ. B. Jackson NASA�Lewis Research CenterD. Lindland Pratt & Whitney

M. J. Lucas, Jr. GE AviationT. R. Morey AFMC LGISA

S. H. Murray NASA�Kennedy Space CenterC. K. Russell NASA�Marshall Space Flight Center

M. E. Sapp NAVAIR In-Service Support Center�Cherry PointC. Sauer NAVAIR In-Service Support Center�Cherry Point

D. Senatore L3 CommunicationsT. Trapp Edison Welding Institute

D. Waldron The Boeing CompanyM. E. Webber Raytheon Integrated Defense SystemsB. D. Wright Advantage Aviation Technologies

Advisors to the D17 Committee on Welding in the Aircraft and Aerospace Industries

D. E. Bell The Boeing CompanyR. Freeman TWI�The Welding Institute

W. P. Garrison Pratt & WhitneyA. Guinasso The Boeing Company

S. Hammond Rolls-Royce CorporationE. M. Lorence Aircraft Welding & Manufacturing CompanyG. Loy-Kraft USAF�Tinker AFB

G. J. Stahle ATK�ThiokelJ. Vollmer The Boeing Company

AWS D17D Subcommittee on Resistance WeldingD. Lindland, Chair Pratt & Whitney

P. Daum, Vice Chair Rolls-Royce CorporationA. M. Alonso, Secretary American Welding Society

R. P. Beil Northrop Grumman CorporationR. J. Durda The Nordam GroupJ. Fournier Pratt & Whitney Canada

D. S. Ponder Triumph Airborne Structures, IncorporatedM. E. Sapp NAVAIR In-Service Support Center�Cherry Point

W. R. Schell The Boeing CompanyR. White Janda Corporation

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Advisors to the D17D Subcommittee on Resistance Welding

G. Loy-Kraft USAF�Tinker AFBR. B. Maust, III Raytheon Integrated Defense Systems

L. P. Perkins USAFS. R. Potter SSP Consulting ServicesJ. Vollmer The Boeing Company

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This foreword is not part of AWS D17.2/D17.2M:2007, Specification for Resistance Weldingfor Aerospace Applications, but is included for informational purposes only.

In the mid 1990s, the AWS D17 Committee on Welding in the Aircraft and Aerospace Industries decided it was neces-sary to form a subcommittee to write a resistance spot and seam welding specification.

This specification is a new document and is intended to replace the following documents:

MIL-W-6858D Welding, Resistance: Spot and Seam, March 28, 1978

AMS-W-6858A Welding, Resistance Spot and Seam, April 1, 2000

MIL-W-6858D or AMS-W-6858A, or both, take precedence over this specification only when they are cited by the contractdocuments.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary,AWS D17 Committee on Welding in the Aircraft and Aerospace Industries, American Welding Society, 550 N.W. LeJeuneRoad, Miami, FL 33126.


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Personnel ......................................................................................................................................................................vForeword ....................................................................................................................................................................viiList of Tables ................................................................................................................................................................xList of Figures...............................................................................................................................................................x

1. Scope .....................................................................................................................................................................11.1 Material Groups ...........................................................................................................................................11.2 Classification ...............................................................................................................................................11.3 Standard Units of Measure ..........................................................................................................................11.4 Safety and Health.........................................................................................................................................1

2. Normative References .........................................................................................................................................1

3. Terms and Definitions.........................................................................................................................................1

4. Requirements .......................................................................................................................................................24.1 Design Requirements...................................................................................................................................24.2 Materials and Methods of Preparation.........................................................................................................24.3 Equipment Requirements.............................................................................................................................44.4 Qualification of Welding Machines.............................................................................................................54.5 Weld Procedure Certification ......................................................................................................................74.6 Production Verification Testing ................................................................................................................134.7 Acceptance Criteria ...................................................................................................................................13

5. Quality Assurance Provisions .........................................................................................................................205.1 Production Quality Control .......................................................................................................................205.2 Production Witness Specimens..................................................................................................................215.3 Inspection of Production Parts...................................................................................................................21

Annex A (Informative)�Form for Resistance Welding Data Sheet for Spot and Projection Welding .....................23Annex B (Informative)�Form for Resistance Welding Data Sheet for Seam Welding ............................................25Annex C (Informative)�Informative References......................................................................................................27Annex D (Informative)�Guidelines for the Preparation of Technical Inquiries ......................................................29

List of AWS Documents on Welding in the Aircraft and Aerospace Industries........................................................31

x

1 Shear Load Requirements for Spot Weld Sheet Specimens, Group 1 Alloys�Aluminumand Magnesium Alloys....................................................................................................................................3

2 Shear Load Requirements for Spot Weld Sheet Specimens, Group 2 Alloys�Steel,Nickel, and Cobalt Alloys ...............................................................................................................................4

3 Shear Load Requirements for Spot Weld Sheet Specimens, Group 3 Alloys�Titanium Alloys ..................54 Shear Load Requirements for Spot Welds in Foil...........................................................................................65 Machine Qualification Test Specimen Requirements .....................................................................................76 Procedure Certification Specimen and Examination Requirements, Spot Welds�Sheet..............................87 Procedure Certification Specimen and Examination Requirements, Spot Welds�Foil ................................98 Procedure Certification Specimen and Examination Requirements, Seam Welds�Sheet ............................99 Procedure Certification Specimen and Examination Requirements, Seam Welds�Foil...............................9

10 Visible External Imperfections for Production Parts ....................................................................................1411 Nugget Size (All Groups)..............................................................................................................................1512 Internal Metallographic Imperfections for Production Witness Samples or Sectioned Parts .......................1713 Production Witness Welds, Test Lots ...........................................................................................................19

1 Spot Welds in Sheet ......................................................................................................................................102 Close Spaced Spot Welds in Sheet................................................................................................................103 Spot Welds in Foil for Class A Welds ..........................................................................................................114 Spot and Seam Welds in Foil, Peel Specimen for Class C Welds ................................................................115 Seam Welds in Sheet.....................................................................................................................................116 Pressure Test of Seam Welds in Foil for Class A Welds ..............................................................................127 Nomenclature for Metallographic Spot Weld Sections and Seam Weld Transverse Sections .....................148 Surface Indentation .......................................................................................................................................149 Nomenclature Diagram of Spot and Seam Weld Radiographs .....................................................................16

10 Minimum Penetration....................................................................................................................................1611 Shear Tests of Three or More Thicknesses ...................................................................................................18

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1. Scope

This specification covers requirements for resistancespot and seam welding of the following metals and theiralloys.

1.1 Material Groups

(1) Group 1�Aluminum and magnesium

(2) Group 2�Steel, nickel, and cobalt

(3) Group 3�Titanium

1.2 Classification. Classification is based on the following:

(1) Class A. A welded joint, whose failure during anyoperating condition would cause loss of the equipment orsystem or one of its major components.

(2) Class B. A welded joint whose failure wouldreduce the overall strength of the equipment or system orlimit the intended functioning or use of equipment.

(3) Class C. A welded joint for which no stress analy-sis is required and whose failure would not affect theperformance of the equipment or system.

1.3 Standard Units of Measure. This standard makesuse of both U.S. Customary Units and the InternationalSystem of Units (SI). The latter are shown within brack-ets [ ] or in appropriate columns in tables and figures.The measurements may not be exact equivalents; there-fore, each system shall be used independently.

1.4 Safety and Health. Safety and health issues and con-cerns are beyond the scope of this standard, and thereforeare not fully addressed herein. Safety and health infor-mation is available from other sources, including, butnot limited to, ANSI Z49.1, Safety in Welding, Cutting,and Allied Processes, and applicable federal and stateregulations.

2. Normative ReferencesThe following standard contains provisions which,through reference in this text, constitute provisions ofthis AWS standard. For undated references, the latestedition of the referenced standard shall apply. For datedreferences, subsequent amendments to, or revisions of,any of these publications do not apply.

(1) AWS A3.0, Standard Welding Terms and Defini-tions Including Terms for Adhesive Bonding, Brazing,Soldering, Thermal Cutting, and Thermal Spraying.1

3. Terms and DefinitionsAll of the terms listed in this clause are used in variousparts of this document and require definition for correctinterpretation of the instructions. Most of these terms arenot contained in AWS A3.0, Standard Welding Termsand Definitions Including Terms for Adhesive Bonding,Brazing, Soldering, Thermal Cutting, and ThermalSpraying. Some of the terms are listed in AWS A3.0, buttheir definitions have been enhanced to clarify their usein this document.

For the purposes of this document, the following defini-tions apply:

close spaced welds. Spot welds on sheet placed less thantwo diameters apart, center to center. Such proximitymay require more power than other spot welds.

Engineering Authority. The contracting agency or cor-poration that acts for and in behalf of the customer onall matters within the scope of this standard. TheEngineering Authority has responsibility for the struc-tural integrity or maintenance of airworthiness of thehardware and compliance with all contract documents.

1 AWS standards are published by the American Welding Society,550 N.W. LeJeune Road, Miami, FL 33126.

2

foil. A thickness of 0.008 in [0.02 mm] or less.

metallographic section. A transverse cut on the diame-ter of a spot weld or across a seam weld, or a longitu-dinal cut down the center of a seam weld, polisheddown to near the center of the weld and etched toaccentuate the metallographic structure.

nugget. The weld (fused) metal joining the parts in spot,seam, or projection welds.

resistance spot weld size. The diameter of a spot weldnugget or the width of a seam weld nugget measuredat the plane of the faying surfaces.

peel test. A mechanical test in which the corners (orsides) of seam or spot welded foil or sheet membersare gripped and pulled apart to determine if the jointfails by delamination, by fracture of a cleaved surface,or by tearing of a button (plug) out of the parent mate-rial. Delamination, in contrast to fracture, is a signof no fusion between the two adjacent members. Abutton or plug, which is pulled out of the removedmember, is not necessarily equal in size to the castnugget underlying it.

penetration. The extent of the nugget or fusion zone intothe thickness of a joined member.

production witness specimens. Welds of specimensmade in production setups and destructively tested toprovide data on the qualities of production weldswhich cannot be tested.

resistance seam welding (RSEW). A resistance weld-ing process which produces coalescence at the fayingsurfaces by the heat obtained from resistance to elec-tric current through the work parts held together underpressure by electrodes. The resulting weld is a seriesof overlapping resistance spot welds made progres-sively along a joint by turning wheel electrodes orindexing the part under fixed electrodes.

resistance spot welding (RSW). A resistance weldingprocess which produces coalescence at the faying sur-faces in one spot by heat obtained from the resistanceto electric current through the work parts heldtogether under pressure by electrodes. The size andshape of the individually formed welds are a functionof the size and contour of the electrodes, current, andweld time.

sheet. A thickness, for the purpose of this specification,of more than 0.008 in through 0.250 in [0.20 mmthrough 6.35 mm].

weld conditions. All circumstances surrounding themaking of a given weld, including material, configu-ration, material preparation, electrode shape, machine

number, and all weld parameters. Weld conditionsthat are relevant require documentation. A suggestedform for documentation is found in Annex A.

weld parameters. Machine settings or adjustments, suchas, but not limited to, weld current, weld time, andelectrode force.

4. Requirements4.1 Design Requirements

4.1.1 Definition of terms used in this specificationshall be in accordance with AWS A3.0, and as shown inClause 3 herein. In the event of any conflict between therequirements of this specification and those requirementsspecified on the engineering drawing, the engineeringdrawing shall prevail.

4.1.2 The class of welding shall be designated on theitem specification or drawing.

4.1.3 Spot Weld Certification. There shall be twomethods of certification for spot welds.

4.1.3.1 Standard Certification. The standard certifi-cation method shall be for a weld schedule that certifiesto the requirements of Tables 1 through 3 (sheet) orTable 4 (foil), and all other applicable weld propertyrequirements listed in this specification have been met.

4.1.3.2 Design Allowable Certification. The designallowable certification method shall be used for a weldschedule that certifies a guaranteed minimum strengthvalue or nugget size, specified on the engineering draw-ing, has been met. Conditions where design allowablecertification shall be permitted are: Where availablespace, equipment or material conditions and designstress permits the use of smaller or lower strength welds;where weld conditions and design stress require larger orhigher strength weld; or where unusual conditions exist(such as welding through adhesives or surface coatings).When design allowable certification is used, the guaran-teed strength value or nugget size and weld class shall bespecified on the engineering drawing.

4.2 Materials and Methods of Preparation

4.2.1 Surface Conditions. The surface of the parts tobe welded shall be free from objectionable films such asheavy oxides, scale, ink, grease, dirt, or other substances,or surface conditions detrimental to the welding process.

4.2.1.1 Cleaning Requirements. These cleaningrequirements shall be used to prepare test material andproduction parts:

3

(1) Oxide coatings may be removed by mechanicaltreatment or by chemical treatment.

(2) The cleaning procedure used to prepare Group 1materials for certification shall be specified on the weldprocedure for production welding. Establishing mini-mum and maximum surface resistance values for test andproduction parts shall be used to ensure conformity isachieved between test and production material and com-pliance to this specification is maintained.

(3) The maximum time span that is permittedbetween cleaning and welding shall be demonstratedsuch that all the quality requirements of this standard canconsistently be met within those time limits. Productionwelding shall be performed within those limits.

(4) When a cleaning procedure is changed, if it can bedemonstrated that the new procedure produces the sameresults as the old procedure, recertification of weldschedules shall not be required as long as the weldparameters meet the requirements of 5.1.5. This confor-mity shall be shown by producing the same weld results(nugget and strength ranges) as made during machinequalification tests (using procedure certification quanti-ties) and, for Group 1 alloys, showing a surface resis-tance (microohms) average that is no more than 1.05times that achieved by the replaced procedure.

4.2.1.2 Surface Coatings. Coatings which im-prove the corrosion resistance or sealing characteristicswithout affecting the weld properties may be applied

Nominal Thicknessof Thinner

Sheet

Ultimate Strength Ultimate Strength Ultimate Strength Ultimate Strength

56 000 psiand abovelb per spot

386 MPaand aboveN per spot

35 000 psi to55 999 psilb per spot

240 MPa to385.9 MPaN per spot

19 500 psi to34 999 psilb per spot


Below19 500 psilb per spot

Below135 MPa

N per spot

in mm Min.Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg.

0.0100.0120.0160.0180.0200.0220.0250.0280.0320.0360.0400.0450.0500.0560.0630.0710.0800.0900.1000.1120.1250.1400.1600.1800.1900.250

0.250.300.400.450.500.550.650.700.800.901.001.101.301.401.601.802.002.302.502.803.203.604.104.604.806.40

6075

110125140160185215260305345405465555670825

1025125514901780212025253120372540357350

7595

140160175200235270325385435510585670840

10351285157018652225265031603900466050459200

265335490555625710825995

1155135515351800207024702980367045605580663079159430

11 23013 88016 57017 95032 695

335425625710780890

10451200144517101935227026002980363516055715698582959895

11 78514 05517 34520 73022 44040 920

5065

100115135155175205235275310370430515610720855

100011701340162519202440300032406400

6585

125145170195200260295345390465540645765900

1070125014651675203524003050375040508000

225290445510600690780910

10451225138016451910229027153200380544505205596072288540

10 58513 34514 41028 465

290380555645755865890

11551310153517352070240028703400400547605560651574509050

10 67513 56516 68018 01535 585

�307085

100120145175210255300350400475570645765870940

10001050��

�4090

110125150185220265320375440500595715810960

1090117512551315

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113513351555178021102535278034003870418044504670

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�175400490555665825980

1180142516701955222526453180360042704850522555805850

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110135165195225260295340395450525595675735785��

�256585

100120140170210245285325370425495565660745845920985��

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�110290380445535625755935

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Note: N = newtons.

4

prior to welding. Such finishes shall be considered asfinal steps of the cleaning procedure and necessary con-ditions shall be specified on the certified weld procedure.

4.2.2 Fitup. Mating parts assembled for welding shallbe processed to fit so that before the first and each suc-cessive weld is made the surfaces to be joined by theweld are in contact with each other or can be made tocontact each other. If the parts are not in contact, use theminimum force necessary to achieve contact but notexceeding the control adjustment requirements of 5.1.5.

4.3 Equipment Requirements

4.3.1 Welding Machines. The welding machine shallconsist of a suitable source of electrical energy, a meansof adequately cooling the electrodes, and a means of reli-ably controlling and indicating the relative magnitude of

the current, the welding force, and the time of currentflow, to fulfill the requirements specified herein. Theforce and current controls shall operate so that no currentcan flow until the welding force is applied by the weld-ing electrodes. Electrode force shall be maintained untilweld current is terminated.

4.3.2 Shear Testing Machines. All shear testingmachines shall be accurate within ±2% of the indicatedreading. The maximum shear testing rate shall notexceed 0.5 in [13 mm] per minute.

4.3.2.1 Stationary Shear Testing Machines. Sta-tionary shear test machines shall be calibrated for accuracyat intervals not to exceed one year.

4.3.2.2 Portable Shear Testing Machines. Portableshear test machines shall be calibrated for accuracy atintervals not to exceed two months.

NominalThicknessof Thinner

Sheet

Ultimate Strength Ultimate Strength Ultimate Strength Ultimate Strength

Above185 000 psilb per spot

Above1275 MPaN per spot

150 000 psi to

185 000 psilb per spot

1034 MPa to1275 MPaN per spot

90 000 psi to 149 999 psilb per spot


Below90 000 psilb per spot

Below620 MPa

N per spot

in mm Min.Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg. Min.

Min. Avg.

0.0090.0100.0120.0160.0180.0200.0220.0250.0280.0320.0360.0400.0450.0500.0560.0630.0710.0800.0900.1000.1120.125

0.220.250.300.400.450.500.550.650.700.800.901.001.101.301.401.601.802.002.302.502.803.20

200245350480590635730870

10251250150017502100245028803550420048505600630070007785

245305410595725785905

107512601545185021502600300035504375515060006900775086009600

890109015552135262528253245387045605560667077859340

10 90012 81015 79018 68021 57524 91028 02031 13534 630

109013551825264532253490402547805605687082309565

10 89513 34515 79019 46022 90526 69030 69034 47038 25542 700

175205275400490530610725855

1045125514601795212525503090373044105090572063657080

210255340495600655755895

10551280154518002210262031453815459554406275705078558730

780910

122517802200235527153225380546505580649579859450

11 34013 74516 59019 61522 64025 44528 31031 490

935113515102200267029153360398046905695687080059830

11 65513 99016 97020 44024 19527 91031 36034 94038 830

130160200295340390450530635775920

10651285150517702110253530053515400045455065

160195245365415480550655785955

114013101585185521852595312537054335493556106250

580710890

1310151017352000235528253445409047355715669578759385

11 27513 36515 63517 79020 21522 530

710865

1090162518452135244529153400425050705825705082509720

11 54513 90016 48019 28021 68024 95527 800

100115150215250280330400465565690815

1005119514601760208024552885330037954300

125140185260305345405495575695860

10001240147518002170256030253560407046755310

440510665955

1110124514701780207025153070362544705315649578309250

10 92012 83014 68016 88019 125

555625825

1155135515351800220025553090382544505515656080059650

11 38513 45515 83518 10520 79523 620

Note: N = newtons.

5

4.3.3 Jigs and Fixtures. Jigs and fixtures shall be sodesigned that no welding current can shunt through theminstead of passing through the workpieces. All toolingthat is required to locate welds or assist in the assemblyof welded parts that passes through the magnetic fieldduring the welding operation, should be made of non-magnetic materials insofar as possible.

4.3.4 Maintenance of Equipment. Unless otherwisespecified, each item of equipment shall be inspectedperiodically as recommended by the manufacturer or perRWMA Bulletin 14, Maintenance Manual for Resis-tance Welding Machines. A preventative maintenanceprocedure shall be established and maintenance recordskept.

4.4 Qualification of Welding Machines

4.4.1 Qualification Approval. Qualification shall beperformed on each resistance spot or seam weldingmachine to determine its ability and consistency of oper-ation. The purpose of qualification is to identify and ver-

ify the range of welding for which a machine may beconsidered capable. Weld conditions shall be docu-mented on a Machine Qualification Test Report. Typicalexamples of report forms are given in AWS C1.1M/C1.1, Recommended Practices for Resistance Welding.Such forms may be modified or expanded as required.After approval is obtained, these reports shall be postednear the machine. Existing machine qualifications madeunder previous revisions of this specification shall behonored. Existing weld machine qualifications (made tosuperseded welding specifications) may be accepted asequivalent to this specification at the sole discretion ofthe Engineering Authority (see Annexes A and B).

4.4.2 Machine Qualification Scope. Machines shallbe qualified to meet the weld requirements for the high-est classification in a metal group for which it is intendedto be used in production. A machine qualified to weld tothe requirements of one weld classification in a groupshall be automatically considered qualified for lowerweld classifications. A spot weld machine qualified for

NominalThickness of

Thinner Sheet

Ultimate Strength Ultimate Strength

Above 100 000 psilb per Spot

689.5 MPa and AboveN per Spot

100 000 psi and Belowlb per Spot

Below 689.5 MPaN per Spot

in mm Min Min. Avg. Min. Min. Avg. Min. Min. Avg. Min. Min. Avg.

0.0100.0120.0160.0180.0200.0220.0250.0280.0320.0360.0400.0450.0500.0560.0630.0710.0800.0900.1000.1120.125

0.250.300.400.450.500.550.650.700.800.901.001.101.301.401.601.802.002.302.502.803.20

205275400490530610725855

1045125514601795212525503000338038104290476053205950

265360520635690795945

11101360163019002340276033203900440049605570617068007700

910122517802180235527153225380545155580649579859450

11 34013 34515 03516 94519 08021 17023 66526 465

11801600231028253070353542054940605072508450

10 41012 27514 76517 34519 57022 06024 77527 44530 24534 250

160200295340390450530635775920

10651285150517702110239527003040338037854220

210260385445510585690825

1000120013851670191023002730311535103955439549255490

710890

1310151017352000235533803445409047355715669578759385

10 62512 01013 52015 03516 83518 770

935115517101980227026003070367044505340616074308495

10 23012 14513 85515 61017 59019 55021 90524 420

Note: N = newtons.

6

*See Note 1 above.2. When the actual number of spots per linear inch [number of spots per 25 millimeters] (Np) is within 15% of the standard spots per inch [spots per

25 millimeters] (No), the tabulated minimum shear loads as noted shall apply.3. When the actual number of spots per linear inch [spots per 25 millimeters] (Np) differs from the standard spots per inch [spots per 25 millimeters]

(No) by 15% or greater, but do not exceed the above noted spots per inch range [spots per 25 millimeter range] (R), the applicable modifiedminimum shear load (Sx) shall be determined by using the formula below.Sx = (So) (K) (Np/No)Where:(No) is defined as the recommended (standard) number of spots per linear inch [spots per 25 millimeters].(So) is defined as the minimum shear load in pounds per linear inch [newtons (N) per millimeter (mm)] of test coupon in the table above.(Np) is the actual number of spots per linear inch [spots per 25 mm] on a production part or representative specimen or coupon.(Sx) is the modified minimum shear load in pounds per linear inch [newtons (N) per millimeter (mm)] of test coupon when the difference of (Np) isgreater than 15% of (No).(K) is the constant shown below:K = 1.15 when the number of spots per linear inch [spots per 25 mm] in the production weld or test sample (Np) is less than 15% (0.85No) of thestandard number of spots per linear inch [spots per 25 mm] required by the table above (i.e., see Note 2). If Np is less than 0.85No, then the modifiedminimum shear load (Sx) is obtained by using the following formula:Sx = So (1.15) (Np/No)K = 0.90 when the number of spots per linear inch [spots per 25 mm] in the production weld or test sample (Np) is greater than 15% (1.15No) of thestandard number of spots per inch [spots per 25 mm] required in the table above (i.e., see Notes 1 and 2). If Np is greater than 1.15No, then themodified minimum shear load (Sx) is obtained by using the following formula:Sx = So (0.90) (Np/No)

Thicknessof Outer

Sheet

Standard Numberof Spots per inch [25 mm]

Acceptable RangeSpots

per inch[25 mm]1

Group 1 Alloys with an Ultimate Strength of

Group 2 and 3 Alloys with anUltimate Strength of

Minimum Shear Load: Pounds per Linear inch[Newtons (N) per Linear millimeter (mm)]: (So)2, 3

in mm (No) R

Up to 56ksi

Up to 386 MPa

Above 56ksi

Above 386 MPa

Up to 90ksi

Up to 620 MPa

90 ksi to 149

ksi

620 MPa to 1033.9 MPa

150 ksi to 185

ksi

1034 MPa to 1275 MPa

Above 185ksi

Above 1275 MPa

0.0010.0020.0030.0040.0050.0060.0070.008

0.030.050.080.100.130.150.180.20

40201210

9765

1�501�301�171�141�131�101�81�7

20406590

115125140160

3.57.0

11.315.820.121.924.528.0

3060

100135165185210235

5.310.517.523.628.932.436.841.2

4590

150190235275320355

7.915.826.333.341.148.256.062.2

65130205285340380440490

11.322.835.949.959.566.577.085.8

80160260350425475550610

14.028.045.561.374.483.296.3

106.8

90180300405490540630690

15.831.552.570.985.894.6

110.3120.8

Notes:1. When the number of spots per linear inch [spots per 25 millimeters] in a production sample or test sample (Np) is greater than the number specified

in the range (R) listed in the table above, the minimum shear load shall remain constant at the value obtained at the top of the range.The following is given as an example to help calculate the modified minimum shear load requirements:If the Group 2 (110 ksi) material thickness is 0.002 in [0.05 mm], what would the (Sx) be for various (Np).No = 20 spot welds 0.85 No =17 spot welds 1.15 No = 23 spot welds So = 130 lbs/in [22.8 N/mm]If Np is less than 15% of No, then Sx = Np/20 1.15 130 lbs/in [Np/20 1.15 22.8 N/mm]If Np is greater than 15% of No, then Sx = Np /20 0.90 130 lbs/in [Np /20 0.90 22.8 N/mm]

Np

Sx[lbs per inch (in)]

Sx [newtons (N) per millimeter (mm)] Np

Sx[lbs per inch (in)]

Sx [newtons (N) per millimeter (mm)]

17161514131210

98765

127.1119.6112.1104.7

97.289.774.867.359.852.344.937.4

22.321.019.718.417.015.713.111.810.5

9.27.96.6

232425262728293031323334

134.6140.4146.3152.1158.0163.8169.7175.5175.5*175.5*175.5*175.5*

23.624.625.726.727.728.729.830.830.8*30.8*30.8*30.8*

7

spot welding is also qualified for overlap spot welding.Machines used for Class C foil welding are qualified byestablishing a weld procedure certification. Machinesqualified to a class for seam welding shall be consideredqualified for roll spot welding to the same class.

4.4.2.1 Test Conduct. No maintenance work andno control adjustments are permitted during the weldingof a set of test specimens.

4.4.2.2 Test Materials. The test materials for aGroup 1 qualification shall be any aluminum alloy com-monly used in resistance welded products. For Groups 2and 3, qualification test material shall be any steel or tita-nium alloy commonly used in resistance welded products.

4.4.2.3 Test Specimen Requirements. Weld testslisted in Table 5 shall be performed and shall meet appli-cable acceptance criteria. For each group of alloys, twotest sets shall be required�one at the highest (thickest tothickest) end of the thickness range and one at the lowest

(thinnest to thinnest) end of the thickness range forwhich the qualification is desired.

4.4.2.4 Weld Machine Requalification. Requali-fication shall be required if the machine is rebuilt or ifsignificant operational changes are made. When machinerequalification is required, all procedures shall meetapplicable acceptance criteria of 4.7. Changes that do notrequire requalification of weld machine are:

(1) Change of location within a plant, which maintainsthe same electrical circuit.

(2) General machine maintenance.

(3) Parts replacement such as electrodes and elec-trode holders that do not affect the pressure or powercharacteristics.

4.5 Weld Procedure Certification

4.5.1 Procedure Certification. Tests shall beconducted to determine if a particular machine, in

Alloy Group Class Specimen Amount per Set Visible Radiographic Mechanical Metallographic

Spot Welds�Sheet

11

2, 32, 3

AB, C

AB, C

Figure 1(B)Figure 1(B)

Figure 1(A) or (B)Figure 1(A) or (B)

105 welds105 welds105 welds105 welds

AllAllAllAll

AllNoneAll

None

100 shear100 shear100 shear100 shear

5 microsections5 microsections5 microsections5 microsections

Spot Welds�Foil

1, 2, 3A Figure 3

12 in [300 mm] continuous

length of weldAll All 10 shear 2 microsections

C Figure 4 see 4.4.2

Seam Welds�Sheet

1, 2, 3

A Figure 524 in [600 mm]

continuous length of weld

All All None8 microsections(4 transverse,

4 longitudinal)

B, C Figure 524 in [600 mm]


All None None8 microsections(4 transverse,

4 longitudinal)

Seam Welds�Foil

1, 2, 3A Figure 6

12 in [300 mm] continuous

length of weldAll All Pressure Test

2 microsections(1 transverse,

1 longitudinal)

C Figure 4 see 4.4.2

8

combination with a specific weld procedure and otherspecific conditions, will on a given set of materials pro-duce resistance welds that conform to the requirementsof this specification. Documentation of these tests will becontained in a completed Certified Weld Procedure TestReport that will be available to the Quality Assurance(QA) personnel. In addition, the weld procedure shall beposted near the machine and be available to machineoperators and QA. The following shall be included in theprocedure certification and any changes of these criticalitems outside the allowable limits of 5.1.5 shall requirerecertification:

(1) Pressure

(2) Electrode type (geometry and material class)

(3) Weld settings (time, current, number of cycles)

(4) Surface preparation

(5) Weld overlap (RSEW)

(6) Travel speed (RSEW)

4.5.2 Procedure Certification Test Reports. Foreach machine and each combination of relevant materialconditions (such as alloy, temper, surface conditions, andthickness combinations), the contractor will determine theeffective weld machine settings for test and productionparts. The conditions and parameters shall be formallyentered on a weld procedure before the test welding. Typ-ical examples of report forms are given in Annexes A andB. These shall be modified or expanded as required. Afteracceptance, production setups shall be made to the certi-fied procedure, with the variation of 5.1.5 allowed.

4.5.2.1 Examination Data. Certification testreport shall include the shear strength data on each weld,their average, the numbers of specimens with shear val-ues outside of the set limits, and the nugget diametersand penetration of each metallographic specimen. Theexamination page shall have a formal indication of thesuccess or failure to meet the certification criteria appli-cable to the subject material combination.

4.5.3 Test versus Production Conditions. The pur-pose of certification is to replicate the results expected onproduction components; therefore, test conditions forcertification shall correspond with expected productionconditions. These conditions include, but are not limitedto: Welding over or adjacent to existing resistance orfusion welds, minimum edge distance, overlap distance,surface preparation (including shot peening, chemicalmilling, or other surface preparation), and heat treatment.

4.5.4 Procedure Certification Test Specimen Con-figuration and Examination Requirements. Tests shallbe as specified in Tables 6 through 9 and as shown inFigures 1 through 6. Welds shall be located within±0.060 in [±1.5 mm] of specimen centers. Specimen sizetolerance shall be ±0.060 in [±1.5 mm].

4.5.5 Thickness Latitudes. Thickness combinationsfalling within the following limits shall not require sepa-rate certified weld procedures provided that the certifiednugget size average can be reproduced with a weld heat(current) setting that lies within ±10% of the value estab-lished by the original certification procedure; all otherconditions being the same.

TypeAlloyGroup Class Specimen

Numberof Welds

Examination

Visible4.7.1

Radiographic4.7.2

Mechanical4.7.4

Metallographic4.7.3

Isolatedor

Roll Spot

1ABC

Figure 1(A) or (B)Figure 1(A) or (B)Figure 1(A) or (B

2515

5

AllAllAll

AllNoneNone

20 Shear10 Shear

3 Shear

5 microsections5 macrosections2 macrosections

2, 3ABC

Figure 1(A) or (B)Figure 1(A) or (B)Figure 1(A) or (B)

1385

AllAllAll

AllNoneNone

10 Shear5 Shear3 Shear


CloseSpace 1, 2, 3

ABC

Figure 2Figure 2Figure 2

2010

3

AllAllAll

AllNoneNone

NoneNoneNone


9

AlloyGroup Class

Specimen Configuration Length of Weld

Examination

Visible Radiographic Mechanical Metallographic

1, 2, 3

.A Figure 312 in [300 mm]


All All 5 Shear and Peel3 in [75 mm] 2 in [50 mm]

C Figure 412 in [300 mm]


All None Peel (10 in [250 mm]minimum length) None

AlloyGroup Class


Examination

Visible4.7.1

Radiographic 4.7.2

Metallographic4.7.3

1, 2, 3

A Figure 512 in [300 mm]

continuouslength of weld

All All 4 transverse microsections (Tr)4 longitudinal microsections (Lo)

B Figure 512 in [300] mm


All None 4 transverse microsections (Tr)4 longitudinal microsections (Lo)

C Figure 5 12 in [300 mm] continuous

length of weld

All None 1 transverse macrosections (Tr)2 longitudinal macrosections (Lo)

AlloyGroup Class


Examination

Visible4.7.1

Radiographic4.7.2

Mechanical4.7.4

Metallographic4.7.3

1, 2, 3

A Figure 6(A)12 in [300 mm]


All All Pressure Test4.7.4.5(1)(a) 1 in [25 mm]

C Figure 412 in [300 mm]


All NonePeel 4.7.4.4

(10 in [250 mm]minimum length)

1 in [25 mm]

10

Figure 1�Spot Welds in Sheet

Figure 2�Close Spaced Spot Welds in Sheet

11

Figure 3�Spot Welds in Foil for Class A Welds

Figure 4�Spot and Seam Welds in Foil, Peel Specimen for Class C Welds

Figure 5�Seam Welds in Sheet

12

(1) Foil. The variation in thickness (with regard to theoriginal procedure) of either outer sheet is within ±0.001 in[±0.03 mm] and the variation in summed thickness (withregard to the original procedure) of the combination iswithin ±0.003 in [±0.08 mm].

(2) Sheet (outer) up to 0.040 in [1.02 mm], inclusive:

(a) The variation in thickness of either outer sheetis within ±0.004 in [±0.10 mm].

(b) The variation in the summed thickness of thecombination is within ±0.006 in [±0.15 mm].

(3) Sheet (outer) over 0.040 in [1.02 mm]:

(a) The variation in thickness of either outer sheetis within ±10% for Group 1 alloys, or ±20% for Groups 2and 3 alloys and

(b) The variation in the summed thickness of thecombination is within ±10%.

Figure 6�Pressure Test of Seam Welds in Foil for Class A Welds

13

4.5.6 Design Allowable Certification. A weld proce-dure shall be certified to produce the minimum strength,nugget size or quality requirement specified on the engi-neering drawing and this specification. This certificationmethod is limited to spot welds in sheet, except for closespaced spot welds. Certification results shall be enteredon the test report, which includes the settings used toweld the coupons. Weld settings shall not be adjustedduring the welding of the certification coupons. Aftercertification acceptance, production setups shall beallowed to deviate from the weld procedure as allowedby 5.1.5.

4.5.6.1 Design Allowable Certification forStrength. When a minimum strength is specified on theengineering drawing, the following shall be used to com-plete the weld procedure certification: The certificationreport shall state: �These conditions certify a strengthvalue of ____.� The number entered shall be the value ofthe lowest strength specimen in 300 welds for Class A,180 welds for Class B, and 50 welds for Class C. As reli-ability requirements warrant, the required number (e.g.,300) may be changed by the cognizant engineeringauthority through drawing notes or design specifications.Weld coupon configuration shall be as specified for stan-dard certification method.

4.5.6.2 Design Allowable Certification for Nug-get Size. When a minimum nugget size is specified onthe engineering drawing, the following shall be used tocomplete the weld procedure certification: The certifica-tion report shall state: �These conditions certify a nuggetvalue of ____.� The number entered shall be the value ofthe smallest nugget size measured in 30 welds for ClassA, 20 welds for Class B, and 10 welds for Class C. Asreliability requirements warrant, the required number(e.g., 30) may be changed by the cognizant engineeringauthority through drawing notes or design specifications.Weld coupon configuration shall be as specified for stan-dard certification method.

4.5.7 Procedure Recertification. Recertificationshall be required if the machine is rebuilt or if significantoperational changes are made to it as specified in 4.5.1.An existing weld schedule need not be recertified foranother contract or designs provided all material condi-tions are equal. Existing certifications made under super-seded revisions of this specification shall be honored.However, recertification of a specification may be re-quired at any time if the procuring activity doubts for anyreason the ability of a machine to make welds satisfacto-rily with the original certification conditions. Changesthat do not require recertification of weld procedure are:

(1) Change of location within a plant, which does notinvolve a change in electrical circuit

(2) General machine maintenance

(3) Electrode replacement

4.5.8 Existing Procedure Certifications. Existingprocedure certifications may be accepted as equivalent tothe requirements of this specification at the sole discre-tion of the Engineering Authority.

4.6 Production Verification Testing. Periodic testsshall be conducted to determine if a particular machine,in combination with a specific weld procedure and otherspecific conditions used during production, producesresistance welds that conform to the requirements of thisspecification. These tests shall conform to 5.2 of thisspecification. Documentation of these tests shall be con-tained in an individual register (logbook) for each resis-tance welding machine. In addition, the register shall belocated in the resistance welding work area and be avail-able for review.

4.7 Acceptance Criteria. This subclause defines weldacceptance criteria for machine qualification, procedurecertification, and production conducted under the stan-dard certification method. For design allowable certifica-tion, the engineering authority shall specify on theengineering drawing which tests to perform and appro-priate acceptance criteria.

4.7.1 Visible Criteria

4.7.1.1 Visual Discontinuities in Test Specimens.Qualification, certifications, and production witness testspecimens shall be smooth, free of cracks, tip-pickup,pits, and other flaws that indicate that the welds weremade with dirty electrodes, improperly prepared sur-faces, or excessive heat and undue force.

4.7.1.2 Visual Discontinuities in Parts or Lot.Visual discontinuities are limited in quantity by Table10. Parts or lots with discontinuities exceeding the quan-tity specified in Table 10 shall be rejected.

4.7.1.3 Sheet Separation. Separation betweenmembers is excessive when it exceeds (1) or (2) (seebelow) measured at a distance as shown in Figure 7.Excessive separation is not acceptable on test specimens.Excessive separation of welds sampled shall not exceed3% for Class A or 10% for Class B and C of productionparts or lots.

(1) Greater than 15% of the summed thickness of theouter sheet and the one adjacent to it, or 0.006 in [0.15 mm],whichever is greater; or

(2) Greater than 0.003 in [0.08 mm] between foil andthe member adjacent to it.

4.7.1.4 Surface Indentation. Indentations (seeFigure 8) are not acceptable if their depth exceeds the

14

Figure 7�Nomenclature for Metallographic Spot Weld Sectionsand Seam Weld Transverse Sections

Figure 8�Surface Indentation

Nature of Weld Imperfections

Acceptable Percentage of Welds Exhibiting Imperfection

Class A Class B Class C

Cracks open to surfaceEdge bulge cracks a

Surface pits over 0.063 in [1.60 mm] dia.Surface pits under 0.063 in [1.60 mm] dia.Flash and surface fusion

0%0%0%3%3%

0%0%0%5%5%

5%10%10%10%10%

a Not acceptable on any test specimens.

15

following limitations (where t is the thickness of theindented outer member). Excessive indentation is notacceptable on test specimens. Excessive indentation ofwelds sampled shall not exceed 3% of measured weldsfor Class A or 10% for Class B and C of production partsor lots.

(1) Sheet; Class A and B: 10% t or 0.005 in[0.13 mm]; whichever is greater.

(2) Sheet; Class C: 20% t or 0.005 in [0.13 mm];whichever is greater

(3) Foil; Class A: 30% t

(4) Foil; Class C: 40% t

(5) When aerodynamic smoothness is a requirement,the outside indentation shall not exceed 0.004 in[0.10 mm] on sheet and 20% of foil thickness.

4.7.2 Radiographic Acceptance Criteria. All ClassA test welds shall be examined for compliance with thefollowing:

4.7.2.1 All welds shall be free of cracks and expulsion.

4.7.2.2 No pore or instance of incomplete fusionshall have a linear dimension greater than 15% of theminimum nugget size as specified in Table 11.

4.7.2.3 No pore or instance of incomplete fusionshall extend into the outer 15% of the nugget radiuswhich is the required clear annulus as shown in Figure 9.

4.7.2.4 Porosity or incomplete fusion in the nuggetshall not have an aggregate area of greater than 5% inGroup 1 alloys, or 10% in Group 2 and Group 3 alloys.

4.7.2.5 The nuggets shall be consistent in size andgenerally round in shape. Welds that exhibit incompletefusion shall not be acceptable.

4.7.3 Metallographic Criteria. The metallographicexamination and acceptance criteria are applicable to qual-ification, standard certification, and production witnessspecimens. Examination and acceptance criteria apply toproduction parts in the event of a test. Metallographicnomenclature is shown in Figure 7 and Figure 10. Testspecimens shall be cross sectioned, polished, and etchedas closely as possible through the center of the weld formetallurgical examination. Class A welds shall be exam-ined as a microsection at a magnification of 20X to a max-imum of 50X. Classes B and C welds shall be examinedas a macrosection at 10X magnification.

4.7.3.1 Internal Discontinuities. Inclusions,porosity, and instances of incomplete fusion are accept-able within the nugget of metallographic sections, unlessthe nugget contains:

(1) A discontinuity within 15% of the nugget�s radiusfrom the edge of the nugget.

(2) A discontinuity extending into an outer sheetmore than 25% of the sheet thickness for Class A andClass B welds.

Nominal Thicknessof Thinner Sheet Nugget Size (Ds)

Nominal Thicknessof Thinner Sheet Nugget Size (Ds)

in [mm] in [mm] in [mm] in [mm]

0.0010.0020.0030.0040.0050.0060.0070.0080.0100.0120.0160.0180.0200.0220.0250.0280.032

[0.03][0.05][0.08][0.10][0.12][0.16][0.18][0.20][0.25][0.30][0.40][0.45][0.50][0.55][0.65][0.70][0.80]

0.0100.0150.0200.0300.0350.0400.0450.0500.0600.0700.0850.0900.1000.1050.1200.1300.140

[0.25][0.38][0.50][0.76][0.89][1.02][1.14][1.27][1.52][1.78][2.16][2.29][2.54][2.68][3.05][3.30][3.56]

0.0360.0400.0450.0500.0560.0630.0710.0800.0900.1000.1120.1250.1400.1600.1800.190

�

[0.90][1.00][1.10][1.20][1.40][1.60][1.80][2.00][2.30][2.50][2.80][3.20][3.60][4.10][4.60][4.80]

�

0.1500.1600.1700.1800.1900.2000.2100.2250.2400.2500.2600.2800.3000.3200.3400.350

�

[3.81][4.06][4.32][4.57][4.82][5.08][5.33][5.72][6.10][6.35][6.60][7.11][7.62][8.13][8.64][8.89]

�

16

Figure 9�Nomenclature Diagram ofSpot and Seam Weld Radiographs

Figure 10�Minimum Penetration

17

(3) A discontinuity extending into an outer sheetmore than 50% of the sheet thickness for Class C welds.

(4) A discontinuity with its largest dimension exceed-ing 10% for Class A welds, 15% for Class B welds, and25% for Class C welds of the nugget diameter.

(5) All welds shall be free of cracks.

(6) For certification and qualification, Class A andClass B weld test specimens shall not exhibit expulsionor the unacceptable discontinuities of 4.7.3.1(1), (2), (3),(4), and (5).

4.7.3.2 Excessive Discontinuities. For productionwitness specimens or parts sectioned for routine or postproduction tests, if the discontinuities, insufficient pene-tration or excessive penetration exceed the percentage ofthe test lot permitted by Table 12, then all work com-pleted since the most recent acceptance test or throughthe end of the shift, whichever occurs first, shall berejected. The provisions of 5.1.5, 5.3.3, and 5.3.4 shall becontinuously applied as a referee.

4.7.3.3 Incomplete Fusion. Whenever a metallo-graphic section of a production witness specimen or partreveals incomplete fusion, welding shall be stopped andparts made after the last acceptable group of witness spec-imens shall be subjected to material review procedures.

4.7.3.4 Penetration. At least 80% of the measurednugget diameter shall exceed the minimum penetrationrequirement. Maximum penetration shall be measured atthe maximum extent into the outer sheets (see Figure10).

(1) Minimum Penetration. Penetration shall complywith the following:

(a) In two equal-thickness members, penetrationshall exceed 0.2 times the thickness of each member intoeach member.

(b) In two unequal-thickness members, pene-tration shall exceed 0.2 times the thickness into eachrespective member.

(c) In three or more thicknesses, penetration intothe outer members shall exceed 0.2 times the thicknessof each outer member.

(2) Maximum Penetration. Penetration shall not exceed:

(a) Group 1 Materials. 80% for Class A and ClassB welds, 90% for Class C welds.

(b) Group 2 and 3 Materials. 90% for all classes.

4.7.3.5 Nugget Size. The minimum nugget size forspot welds shall be those specified in Table 11. In weldsof two members of unequal thickness, the thinner mem-ber shall determine the required minimum nugget size atthe faying surface. In three or more thickness welds, thethinner of the two outer members shall determine theminimum nugget size from Table 11, unless load-carryingmembers are identified for the certification combinations,such as in Figures 11(C) and 11(D). In this case, thelesser thickness of the two load carrying members shallidentify and be the determinant of minimum nugget sizefor each interface lying between them. Each nugget shallbe measured at the subject interface plane on the metallo-graphic section through the center of the nugget. Class Afoil weld size may be measured by the size of the frac-tured peel specimen instead of a metallographic section,when the foil is an outer member.

(1) Seam and Intermittent Welds. Seam and intermit-tent weld nugget size shall be determined by transversesections and shall comply with the spot weld sizerequirements listed in Table 11. Seam and intermittentwelds shall exhibit uniform overlap in a longitudinal sec-tion of not less than 25% of the nugget size as measuredin a transverse section.

Nature of Weld Imperfections

Acceptable Percentage of Welds Exhibiting Imperfection

Class A Class B Class C

Porosity, Cracks, Incomplete-Fusion (4.7.3.1)Insufficient Penetration [4.7.3.4(1)]Excessive Penetration [4.7.3.4(2)]Insufficient Size (4.7.3.5)

0%0%0%0%

6%3%3%3%

N/AN/AN/AN/A

18

(2) Machine Qualification and Procedure Certifica-tion. The nugget size of all required metallographic sec-tions will be measured for each interface plane andrecorded. From the values of each plane the average sizeand the lowest size in the test group will be entered onthe test record form. The peel test of Class A foils, inaddition to Table 11, also requires that the largest nuggetsize not be more than 120% of the smallest nugget size.

(3) Production Witness Specimens

(a) Nugget size measurement shall be the processcontrol method for close spaced spot welds, as defined inTable 13, and for seam welds and may be an alternatemethod to spot shear tests of sheet [shear tests of produc-tion witness specimens, 4.7.4.1(2)]. Size shall be mea-sured on metallographic sections. Nugget size can alsobe measured on peel specimens when approved by theEngineering Authority.

(b) Class A welds shall be within ±10% of theaverage nugget size recorded for procedure certificationor no more than 0.020 in [0.50 mm] smaller than thecertification average, when the average is larger than0.200 in [5.08 mm]. Class B welds shall be within ±20%of the procedure certification nugget size average.

(c) All welds shall meet the minimum nuggetrequirements as specified in Table 11.

4.7.4 Mechanical Criteria

4.7.4.1 Spot Welds�Sheet

(1) Procedure Certification and Machine Qualification

(a) Minimum. Each and every shear test speci-men, such as Figure 1(A) or Figure 1(B) (see 4.5.4), shallequal or exceed the minimum strength required byTables 1 through 3.

(b) Average. The average shear strength shallequal or exceed the applicable minimum averagestrength specified in Tables 1 through 3.

(c) Consistency�Group 1 Materials. For Class Aand Class B welds, 90% of the number of welds testedshall have shear strength values within 12.5% of the lotaverage. Each of the remaining 10% of the welds shallhave shear strength values within 25% of the lot average.All Class C welds shall be within 35% of the lot average.

(d) Consistency�Group 2 and 3 Materials. ForClass A and Class B welds, each of 90% of the numberof welds tested shall have shear strength values within10% of the lot average. Each of the remaining 10% of thewelds shall have shear strength values within 20% of thelot average. All Class C welds shall be within 33% of thelot average.

(2) Production Witness Specimens. The spreadbetween the lowest and highest specimen shall be lessthan 35% of the applicable production test lot average.

(a) Class A. The test lot average shall be not lessthan 90% of the certification average and no weld shallbe less than the applicable minimum value shown inTables 1 through 3.

(b) Class B and Class C. The test lot average shallbe not less than the applicable value shown in Tables 1through 3.

4.7.4.2 Design Allowable Certification for Sheet

(1) Minimum. The value of the lowest specimen in thetest lot shall exceed the specified design minimum.

(2) Average. The test lot average (Ac) shall berecorded on the certification report form.

(3) Consistency. 95% of the number of specimenstested shall have values greater than 0.875 times the testlot averages (Ac).

Figure 11�Shear Tests ofThree or More Thicknesses

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4.7.4.3 Production Witness Specimens�DesignAllowable Certification for Sheet

(1) Average. The average strength or nugget size ofthe production test lot shall be not less than 0.94 timesAc for Class A welds, and not less than 0.90 times Ac forClass B and Class C welds, without consideration of theprovisions of 5.3.4.

(2) Consistency. No specimen in a group of three con-secutive test lots (nine specimens) for Class A welds ortwo consecutive test lots (six specimens) for Class B andClass C welds may be less than 0.88 times Ac for ClassA welds, 0.83 times Ac for Class B welds, and 0.80 timesAc for Class C welds.

4.7.4.4 Spot Welds�Foil (Less Than or Equal to0.008 in [0.20 mm])

(1) Procedure Certification and Machine Qualification

(a) Class A. Each shear specimen shall equal orexceed the applicable values in Table 4. In addition, thepeel test run shall cause a button (plug) pull-out failure inat least 95% of the welds tested. The remaining 5% mayfail at the interface plane, but the cleavage in each caseshall be of a fused zone that is at least 80% of the averagebutton size.

(b) Class C. Peel tests shall cause a button pull-out failure in at least 85% of the welds tested. The

Class SpecimenAmount of Weld

in Test Lotc

Examination

Mechanical a, c

Metallographic RequirementbTest Requirement

Spot Welds�Sheet

ABC

Figure 1(A) or 1(B)Figure 1(A) or 1(B)Figure 1(A) or 1(B)

3 welds3 welds3 welds

ShearShearShear

4.7.4.1(2)4.7.4.1(2)4.7.4.1(2)

4.7.34.7.34.7.3

Spot Welds�Sheet�Close Space

ABC


3 Weld3 Weld3 Weld

NoneNoneNone

4.7.34.7.34.7.3

Spot Weld�Foil

AC

Figure 3Figure 4

3 weld1 in [75 mm]

PeelPeel

4.7.4.4(2)(a)4.7.4.4(2)(b)

4.7.34.7.3

Seam Welds�Sheet

ABC


3 in [75 mm]3 in [75 mm]3 in [75 mm]

NoneNoneNone

4.7.34.7.34.7.3

Seam Welds�Foil

AC

Figure 4Figure 4

3 in [75 mm]3 in [75 mm]

PeelPeel

4.7.4.5(2)(a)4.7.4.5(2)(b)

4.7.34.7.3

a See 5.2.1 and 5.2.2.b Seam welds shall require metallographic evaluation of 2 transverse and 1 longitudinal sections.c Default examination for production witness welds is metallographic, but when mechanical tests are used for examination of witness production weld

compliance of spot welds established by the standard certification procedure, then three welds will be added for metallographic examination (4.7.3)to the preproduction lot for Class A and Class B welding, and three welds for metallographic examination will be added every fourth routine lot forClass A.

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remaining 15% may fail at the interface plane, but thereshall be evidence of fusion at the interface in each case.

(2) Production Witness Specimens. The required testlot shall be tested for compliance with the peel require-ments only of 4.7.4.4(1)(a) for Class A welds or4.7.4.4.(1)(b) for Class C welds.

(a) Class A. The weld specimen shall be tested inpeel. Failure shall be by tearing of the metal adjacent tothe weld nugget for more than 95% of the weld length.The remaining portion of the weld length may fail byfracture across the faying plane, but the smallest nuggetsize (fusion) shall be not less than 0.80 times the averagenugget size.

(b) Class C. The weld specimen shall be tested inpeel and shall meet the requirements of 4.7.4.4 (1)(b).

4.7.4.5 Seam Welds�Foil

(1) Procedure Certification and Machine Qualifica-tion Requirements (Acceptance Criteria)

(a) Class A. A pressure test specimen as shown inFigure 6 (see 4.5.4) shall show no evidence of leakagethrough the joint while under a pressure greater than (1)25% of the specimen burst pressure for qualification, or(2) the greatest pressure to be experienced by the weld inits assigned service, as noted on the applicable drawingfor certification. Examination for leaks shall begin notless than one minute after the specimen has reached itsspecified load. After the leak test, the specimen shall beloaded to destruction. Failure shall occur in the metaladjacent to the weld. Failure by cleavage fracturethrough the weld shall be cause for rejection.

(b) Class C. The weld specimen shall be tested inpeel. Failure shall occur by tearing of the metal adjacentto the weld nugget for more than 85% of the weld length.The remaining portion of the weld length may fail byfracture across the weld in the faying plane, but continu-ous fusion shall be evident.

(2) Production Witness Specimens (Acceptance Criteria)

(a) Class A. The weld specimen shall be tested inpeel. Failure shall be by tearing of the metal adjacent tothe weld nugget for more than 95% of the weld length.The remaining portion of the weld length may fail byfracture across the faying plane, but the smallest nuggetsize (fusion) shall be not less than 0.80 times the averagenugget size

(b) Class C. The weld specimen shall be tested inpeel and shall meet the requirements of 4.7.4.5(1)(b).

4.7.4.6 Unusual Specimen Configuration. Speci-mens of unusual configuration shall be tested so as tostress the load carrying members, as specified on the

applicable drawing or part specification. Some examplesof joints with three or more members are shown in Fig-ure 11. The strength requirements of such combinationsshall be determined from Tables 1 through 3 and Table 4based upon the requirement for the thinner loaded mem-ber unless otherwise specified on the applicable drawingor part specification. Test specimen members not loaded(unshaded) may be coupons laid crosswise or parallel tothe load, may be short pieces, or may be positioned outof the way of the test fixture. The minimum width of thespecimen and overlap shall be based on the thickness ofthe thinnest loaded member.

5. Quality Assurance Provisions5.1 Production Quality Control

5.1.1 Procedures. Qualified personnel in each plantshall be responsible for the control of machine settingsand all welding procedures. Certified procedures shall beavailable for examination by any authorized inspector atany time.

5.1.2 Weld Location. Welds shall be located as spec-ified on the engineering drawing or applicable document.

5.1.3 Test Specimens. Certification and productionwitness specimens shall conform to the production partsthey represent with respect to material, thickness, over-lap, configuration, and surface condition or preparation.Production witness specimens shall be run with produc-tion weld conditions using either certification specimensor a simulation of the production part. When productionconditions exist that were not applied during certifica-tion, but cause machine settings to differ from certifica-tion settings so as to exceed the permitted latitude(5.1.5), the certification shall be run again with the sub-ject critical production conditions included. Examples ofsuch production conditions are, but are not limited to,magnetic material in the machine throat, curvature of thepart, spot spacing and part (overlap) width.

5.1.4 Surface Resistance. A daily check shall bemade of the surface resistance in microohms for Group 1(Class A) welds when running production parts. A mini-mum of five readings shall be made on samples typicalof the material being welded and its surface conditionand preparation. The details of the method of obtainingthe surface resistance measurement shall be the same asthose used for the certification of welding procedures orcleaning procedures and the values of the surface resis-tance shall not exceed the limits of consistency and max-imum values established at that time.

5.1.5 Control Adjustments. The settings may be var-ied by ±5% from the established certification values, or

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by ±10% when only one setting is adjusted. Rounded tothe nearest unit this shall be the permitted procedureadjustment. Production welds shall be made within ±5%of the settings used on witness specimens. If satisfactorywelding cannot be maintained within these limits ofadjustment, welding shall be stopped and the machineshall be checked for faulty operation. If it can be shownthat conditions other than those controlled by the certi-fied welding procedure were the cause of the faultywelding and with their correction the original certifiedwelding procedure is capable of producing acceptablewelds, the establishment of a new certified welding pro-cedure will not be required. For Class A welds, also see5.3.4.

5.2 Production Witness Specimens. The followingspecimens shall accompany the welding of productionparts. These specimens will duplicate the productionparts in all conditions controlled by the certified weldingprocedure and the drawing. Results of these tests shall bemaintained in an individual register (logbook) by eachwelding machine.

5.2.1 Test Lots. Test lots of witness specimens forproduction parts shall be as noted below.

Each test lot shall consist of the number and configura-tion of test specimens and method of evaluation as speci-fied in Table 13. Any of the quantities specified may bemade on a simulation of the production joint or a produc-tion part.

(1) Preproduction lot. At the start of each work day orbefore a new production lot is welded or before weldingis resumed after a machine shutdown.

(2) Routine lot. At intervals specified in 5.2.2.1 or5.2.2.2 during production welding and after an electrodechange, or other minor welding equipment change.

(3) Postproduction lot. At the end of each productionwork day or after the completion of a production lot. Thelast routine test lot may be entered as the postproductiontest lot if the production work lot is finished before halfof the required routine time interval has elapsed.

5.2.2 Testing Requirements

5.2.2.1 Class A welds shall be accompanied by thefollowing test lots:

(1) Preproduction lot

(2) Routine lot every one hour maximum of weldtime

(3) Postproduction lot. Postproduction lot not re-quired if welding of production lot is completed within30 minutes of last routine lot.

5.2.2.2 Class B welds shall be accompanied by thefollowing test lots:


(2) Routine lot every two hours maximum of weldtime

(3) Postproduction lot. Postproduction lot notrequired if welding of production lot is completed within60 minutes of last routine lot.

5.2.2.3 Class C welds shall be accompanied by thefollowing test lots:


(2) Postproduction lot

5.2.2.4 Single Spot Standard Certification. Sin-gle spot welds established by the standard certificationprocedure may be controlled either by mechanicalstrength [4.7.4.1(2)] or by nugget size with soundnessexamination (4.7.3).

5.2.2.5 Design Allowable Certification SpotWelds. Spot welds established by the design allowablecertification are only required to meet the requirementsfor visible criteria of 4.7.1 and the strength criteria of4.7.4.2 and 4.7.4.3 or nugget size of 4.7.3.5.

5.2.2.6 Visual and Radiographic Requirements.All specimens shall be visually examined in accordancewith 4.7.1. Radiographic examinations of specimensshall not be required, unless otherwise specified in theapplicable drawing or part specification.

5.2.3 Alternate Testing Requirements As an alter-nate to the testing requirements of 5.2.2(1) real time non-destructive SPC system may be used when approved bythe Engineering Authority. As a minimum the SPC sys-tem shall address: part fitup, precleaning, electrode mon-itoring, and in process monitoring of critical processparameters. This system of controls shall include but isnot limited to, real time adaptive controls or in-processNDT methods. Destructive testing shall still be used toestablish and verify that the capability of this SPC sys-tem will identify welds complying with strength or sizerequirements with 99.5% reliability.

5.3 Inspection of Production Parts

5.3.1 External Imperfections. Welds shall be exam-ined for compliance with the visible criteria by determin-ing the presence and number of discontinuities on thefollowing basis.

(1) Class A and B parts�All welds

(2) Class C parts�On sampling basis agreed uponwith Engineering Authority.

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5.3.2 Internal Imperfections. When required, radio-graphically inspect per 4.7.2 and metallographicallyinspect per 4.7.3.

5.3.3 Distribution of Imperfections. Imperfectionsare instances of external or internal discontinuities ordepartures from specified dimensions. They begin toaffect the weld and welded assemblies when theyachieve the dimensions of:

(1) 4.7.1 for visible

(2) 4.7.2 for radiographic

(3) 4.7.3 for metallographic sizes

5.3.3.1 Production parts and lots are acceptable aswelded with discontinuities of the sizes stipulated, pro-vided the quantity does not exceed:

(1) 4.7.1 for visible

(2) 4.7.2 for radiographic

(3) 4.7.3 for metallographic kinds

(4) The discontinuities shall be randomly distributedand not clustered in one area, in one part, or in one groupof parts.

5.3.3.2 When discontinuities (of the size stipulatedby 5.3.3) exceed the quantity limited by the paragraphsreferenced in 5.3.3.1, but do not exceed twice that quan-

tity limit, the manufacturer may use standard repair pro-cedures to make repairs without recourse to salvage ormaterials review action. All standard repair weld proce-dures shall be clearly identified as such. Standard repairprocedures shall be approved by the Engineering Authority.

5.3.4 Deterioration of Welding. If investigation ofimperfections in welding indicates that welding qualityhas deteriorated due to clear causes, (for example,swaged or improperly cleaned tips) and those causes arecorrected so that acceptable welds (compared to certifi-cation requirements) are made, then certification of anew weld schedule will not be required. Under condi-tions where the machine weld schedule does not produceacceptable welds within the weld schedule latitude, thenthe machine qualification shall be voided and themachine shall be requalified. All Class A weld schedulecertifications for that machine shall be discarded andnew certifications shall be established.

5.3.5 Tack Welds. Tack welds shall not be used onClass A parts unless they are allowed on engineeringdrawings or applicable documents and are finallyremoved, or completely covered by subsequent produc-tion welding. Tack welds require no tests and need beonly of sufficient strength to fulfill their temporary func-tion. They are not subject to this specification except thatresidual discontinuities shall not exceed limits estab-lished for production parts.

23

This annex is not part of AWS D17.2/D17.2M:2007, Specification for Resistance Weldingfor Aerospace Applications, but is included for informational purposes only.

24

Source: AWS C1.1M/C1.1:2000, Figure 34, p. 99.

25

This annex is not part of AWS D17.2/D17.2M:2007, Specification for Resistance Weldingfor Aerospace Applications, but is included for informational purposes only.

26

Source: AWS C1.1M/C1.1:2000, Figure 35, p. 100.

27

(1) American Welding Society (AWS) A2 Committeeon Definitions and Symbols, 1998, Standard Symbols forWelding, Brazing and Nondestructive Examination,AWS A2.4-98, Miami: American Welding Society.

(2) American Welding Society (AWS) C1 Committeeon Resistance Welding, 2000, Recommended Practices

for Resistance Welding, AWS C1.1M/C1.1:2000,Miami: American Welding Society.

(3) Resistance Welding Manufacturing Alliance(RWMA), 1996, RWMA Bulletin 14, MaintenanceManual for Resistance Welding Machines, Miami:American Welding Society.

This annex is not part of AWS D17.2/D17.2M:2007, Specification for Resistance Welding

for Aerospace Applications, but is included for informational purposes only.


28

29

D1. IntroductionThe American Welding Society (AWS) Board of Directorshas adopted a policy whereby all official interpretationsof AWS standards are handled in a formal manner.Under this policy, all interpretations are made by thecommittee that is responsible for the standard. Officialcommunication concerning an interpretation is directedthrough the AWS staff member who works with thatcommittee. The policy requires that all requests for aninterpretation be submitted in writing. Such requests willbe handled as expeditiously as possible, but due to thecomplexity of the work and the procedures that must befollowed, some interpretations may require considerabletime.

D2. ProcedureAll inquiries shall be directed to:

Managing DirectorTechnical Services DivisionAmerican Welding Society550 N.W. LeJeune RoadMiami, FL 33126

All inquiries shall contain the name, address, and affilia-tion of the inquirer, and they shall provide enough infor-mation for the committee to understand the point ofconcern in the inquiry. When the point is not clearlydefined, the inquiry will be returned for clarification. Forefficient handling, all inquiries should be typewritten andin the format specified below.

D2.1 Scope. Each inquiry shall address one single provi-sion of the standard unless the point of the inquiryinvolves two or more interrelated provisions. The provi-sion(s) shall be identified in the scope of the inquiry

along with the edition of the standard that contains theprovision(s) the inquirer is addressing.

D2.2 Purpose of the Inquiry. The purpose of theinquiry shall be stated in this portion of the inquiry. Thepurpose can be to obtain an interpretation of a standard�srequirement or to request the revision of a particular pro-vision in the standard.

D2.3 Content of the Inquiry. The inquiry should beconcise, yet complete, to enable the committee to under-stand the point of the inquiry. Sketches should be usedwhenever appropriate, and all paragraphs, figures, andtables (or annex) that bear on the inquiry shall be cited. Ifthe point of the inquiry is to obtain a revision of the stan-dard, the inquiry shall provide technical justification forthat revision.

D2.4 Proposed Reply. The inquirer should, as aproposed reply, state an interpretation of the provisionthat is the point of the inquiry or provide the wording fora proposed revision, if this is what the inquirer seeks.

D3. Interpretation of Provisions of the Standard

Interpretations of provisions of the standard are made bythe relevant AWS technical committee. The secretary ofthe committee refers all inquiries to the chair of the par-ticular subcommittee that has jurisdiction over the por-tion of the standard addressed by the inquiry. Thesubcommittee reviews the inquiry and the proposed replyto determine what the response to the inquiry shouldbe. Following the subcommittee�s development of theresponse, the inquiry and the response are presented tothe entire committee for review and approval. Uponapproval by the committee, the interpretation is an official

This annex is not part of AWS D17.2/D17.2M:2007, Specification for Resistance Welding

for Aerospace Applications, but is included for informational purposes only.

30

interpretation of the Society, and the secretary transmitsthe response to the inquirer and to the Welding Journalfor publication.

D4. Publication of InterpretationsAll official interpretations will appear in the WeldingJournal and will be posted on the AWS web site.

D5. Telephone InquiriesTelephone inquiries to AWS Headquarters concerningAWS standards should be limited to questions of a gen-eral nature or to matters directly related to the use of thestandard. The AWS Board Policy Manual requires thatall AWS staff members respond to a telephone requestfor an official interpretation of any AWS standard withthe information that such an interpretation can be

obtained only through a written request. Headquartersstaff cannot provide consulting services. However, thestaff can refer a caller to any of those consultants whosenames are on file at AWS Headquarters.

D6. AWS Technical CommitteesThe activities of AWS technical committees regardinginterpretations are limited strictly to the interpretation ofprovisions of standards prepared by the committees or toconsideration of revisions to existing provisions on thebasis of new data or technology. Neither AWS staff northe committees are in a position to offer interpretive orconsulting services on (1) specific engineering problems,(2) requirements of standards applied to fabricationsoutside the scope of the document, or (3) points notspecifically covered by the standard. In such cases, theinquirer should seek assistance from a competent engi-neer experienced in the particular field of interest.

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Designation Title

D17.1 Specification for Fusion Welding for Aerospace Applications


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PDF Aws d172

Documents

lej eune road

full legal authority

weld imperfectionsacceptable percentage

sdeasdebthickness weld currentapprox

aws disclaims liability

production witness samples

american welding society

close spaced welds