1、AWS D10.7M/D10.7:2008An American National StandardGuide for theGas ShieldedArcWelding ofAluminum andAluminum AlloyPipe550 N.W. LeJeune Road, Miami, FL 33126AWS D10.7M/D10.7:2008An American National StandardApproved by theAmerican National Standards InstituteApril 21, 2008Guide for the Gas ShieldedAr
2、c Welding of Aluminumand Aluminum Alloy Pipe4th EditionSupersedes AWS D10.7M/D10.7:2000Prepared by theAmerican Welding Society (AWS) D10 Committee on Piping and TubingUnder the Direction of theAWS Technical Activities CommitteeApproved by theAWS Board of DirectorsAbstractThis document presents infor
3、mation concerning those properties of aluminum which affect its weldability and whichcause specific problems in the fabrication of aluminum pipe. Recommendations are made for solving these problems andsuggested procedures are presented for welding aluminum pipe joints with the Gas Tungsten Arc and G
4、as Metal ArcWelding Processes.iiAWS D10.7M/D10.7:2008International Standard Book Number: 978-0-87171-099-4American Welding Society550 N.W. LeJeune Road, Miami, FL 33126 2008 by American Welding SocietyAll rights reservedPrinted in the United States of AmericaPhotocopy Rights. No portion of this stan
5、dard 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 i
6、nternal, 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:.iiiAWS D10.7M/D10.7:2008Statement on th
7、e Use of American Welding Society StandardsAll 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
8、 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, a
9、ny 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 thi
10、s 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 view
11、points and interests to achieve consensus. While the AWS administers theprocess and establishes rules to promote fairness in the development of consensus, it does not independently test, evalu-ate, or verify the accuracy of any information or the soundness of any judgments contained in its standards
12、.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 guarantee or warranty
13、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
14、 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. It isassumed that the use of this standard and its provisions are en
15、trusted to appropriately qualified and competent personnel.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
16、 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, the AWS does not monitor, police, or enforce compliance with this standard, nor does it have the p
17、ower 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 writ
18、ing, 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 B).With regard to technical inquiries made concerning AWS standards, oral opinio
19、ns 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 AW
20、S, 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 D10 Committee on Piping and Tub
21、ing. It must be reviewedevery five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations, additions, ordeletions) and any pertinent data that may be of use in improving this standard are required and should be addressed toAWS Headquarters. Such comments will
22、 receive careful consideration by the AWS D10 Committee on Piping andTubing and the author of the comments will be informed of the Committees response to the comments. Guests areinvited to attend all meetings of the AWS D10 Committee on Piping and Tubing to express their comments verbally.Procedures
23、 for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation ofthe Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 550N.W. LeJeune Road, Miami, FL 33126.This page is intentionally blank.ivAWS D10.7M/D1
24、0.7:2008vAWS D10.7M/D10.7:2008PersonnelAWS D10 Committee on Piping and TubingM. P. Lang, Chair United Association, Local 501W. F. Newell, Vice Chair W. F. Newell therefore, each system must be usedindependently. Pipe sizes are listed as DN (diameternominal) and NPS (nominal pipe size). The exact pip
25、ediameters are listed in Annex A.Safety and health issues and concerns are beyond thescope of this standard and therefore are not fullyaddressed herein. Safety and health information is avail-able from other sources, including, but not limited to,ANSI Z49.1, Safety in Welding, Cutting, and Allied Pr
26、o-cesses, and applicable federal and state regulations.2. Normative ReferencesThe following standards contain provisions which,through reference in this text, constitute mandatory pro-visions of this AWS standard. For undated references,the latest edition of the referenced standard shall apply.For d
27、ated references, subsequent amendments to, or revi-sions of, any of these publications do not apply.AWS Documents:2AWS A2.4, Standard Symbols for Welding, Brazing,and Nondestructive Examination1The terms pipe and piping in this standard are intended toinclude tube and tubing where appropriate.2AWS s
28、tandards are published by the American WeldingSociety, 550 N.W. LeJeune Road, Miami, FL 33126.AWS A3.0, Standard Welding Terms and Definitions,Including Terms for Adhesive Bonding, Brazing, Solder-ing, Thermal Cutting, and Thermal SprayingAWS A5.10/A5.10M, Specification for Bare Alumi-num and Alumin
29、um Alloy Welding ElectrodesAWS A5.12/A5.12M, Specification for Tungsten andTungsten Alloy Electrodes for ArcWelding and CuttingAWS A5.32/A5.32M, Specification for Welding Shield-ing GasesAWS B2.1, Standard for Welding Procedure andPerformance QualificationANSI Z49.1, Safety in Welding, Cutting, and
30、AlliedProcesses3. History of Aluminum Pipe WeldingFor many years, pipe was generally joined with threadedfittings. Improved welding techniques gradually caused atrend toward welded joints. Today, welded piping sys-tems are specified in a wide variety of industries, includ-ing power, refrigeration, c
31、hemical, petroleum, industrialgas and air, and food processing.Oxyfuel gas welding with oxyhydrogen or oxyacetylenewas initially used for aluminum pipe. This processrequired the use of fluxes which had to be removed sub-sequent to welding, since they were a corrosion hazard tothe pipe in the presenc
32、e of moisture. Furthermore, weld-ing, other than in the flat position, was very difficult.Both factors imposed a severe limitation on welded alu-minum piping systems.The development of the gas tungsten arc welding(GTAW) process during World War II provided a practi-cal solution to the problems assoc
33、iated with oxyfuel gaswelding aluminum pipe. The corrosion hazard resultingfrom the flux was eliminated by the inert gas shield andall-position welding techniques were developed. Subse-quently, the gas metal arc welding (GMAW) process wasGuide for the Gas Shielded Arc Weldingof Aluminum and Aluminum
34、 Alloy PipeAWS D10.7M/D10.7:20082developed and provided a substantial reduction in pipewelding time for applications where this process wassuitable.4. Aluminum Pipe Alloys and Their CharacteristicsAluminum alloys have many characteristics which makethem useful construction materials. Many of these p
35、roper-ties, such as corrosion resistance, strength, light weight,protection of purity and color of the product transported,fracture toughness at cryogenic temperatures, and ease offabrication are valuable in piping systems.Many aluminum alloys are made in pipe form. Thechoice of the pipe alloy for a
36、 particular installation ismade on the basis of the materials to be contained, theexternal exposure environment, and the service tempera-tures. For nominal chemical compositions, see Table 1.Alloy 3003-H112, a nonheat-treatable alloy containingmanganese, provides adequate strength for many appli-cat
37、ions, together with high corrosion resistance. Alloy6063-T6, a heat treated aluminum-magnesium-siliconalloy, provides higher strength and equivalent corrosionresistance. Alloy 6061-T6 is similar in characteristics to6063-T6, but it has higher strength. In most environ-ments, its corrosion resistance
38、 is equivalent to that ofthe 3003 and 6063 alloys. Alloys 5086 and 5083, non-heat-treatable aluminum-magnesium-manganese alloys,provide superior as-welded strength and high fracturetoughness at ambient and cryogenic temperatures.It should be noted that the heat associated with weldingreduces both te
39、nsile strength and design allowable valuesfor most aluminum alloys. For example, for 6061-T6these values are reduced about one third. For nonheat-treatable alloys, the as-welded properties are normallythose of the “O” temper (i.e., annealed) for that alloy,regardless of the starting temper.Pipe in o
40、ther alloys can be furnished for applicationswhere high purity aluminum is required, where thedesign calls for higher strength, or where special corro-sion resisting characteristics are desired. Alloys such as1060, 5254, or 5652 may be used for high purity require-ments. The 5254 and 5652 alloys are
41、 specially controlledpurity versions of alloys 5154 and 5052. They belong toan important group of alloys which have magnesium astheir principal alloying element.Other alloys in this group are 5083, 5086, 5454, and5456. These alloys are all nonheat-treatable but haveexcellent as-welded strength and d
42、uctility. They gener-ally exhibit high corrosion resistance; however, maxi-mum service temperature requirements must be carefullyinvestigated, since long time exposure to elevated tem-perature can adversely affect their corrosion resistance.Alloys 5052 and 5454 are recommended when sustainedservice
43、temperatures are above 66C 150F. Alloys5083 and 5086 are used in marine applications. Alloy5083 is favored for cryogenic applications.Clad versions of the standard alloys are sometimes usedfor corrosion resistance under special conditions. In theclad products, an integral coating (usually 10% of the
44、pipe wall thickness) of an alloy selected is used to pro-vide cathodic protection to the core alloy. The presenceof the cladding does not normally affect weldability.Combinations of alloys can be welded in most cases, andwelding procedures should be based on core alloys.Annex A lists the diameters,
45、wall thicknesses, andweights of aluminum pipe.5. Welding Characteristics of AluminumThe important characteristics of aluminum which affectits weldability are:(1) Refractory nature of aluminum oxide,(2) Lack of color change as the metal approaches thewelding temperature,(3) High thermal conductivity,
46、 and(4) High coefficient of thermal expansion.5.1 Aluminum Oxide. Aluminum and oxygen have astrong affinity for each other, and aluminum oxideinstantaneously begins to form on aluminum surfacesexposed to air. This oxide film is thin, transparent, tena-cious, and refractory with a melting temperature
47、 threetimes that of aluminum. An excessively thick oxide filmthat has become hydrated through exposure to moisturecan cause welding difficulties and affect weld qualityand should be removed by wire brushing before welding.The normal nonhydrated oxide film is removed progres-sively by the welding arc
48、 during the welding operation.A flux is not required in gas tungsten arc welding(GTAW) or in gas metal arc welding (GMAW). Theelectric arc in both processes breaks up the aluminumoxide film, which is not an electrical conductor. A regu-lated flow of inert gas (either argon or helium, or acombination
49、 of both) around the arc area prevents refor-mation of oxide without contaminating the metal andpermits the welder to deposit filler metal with a highdegree of control. Gas purging of the pipe or gas shieldingof the weld root is not normally necessary for aluminumpipe welds.AWS D10.7M/D10.7:20083Table 1Nominal Composition of Aluminum AlloysPercent by WeightAluminum and Normal Impurities Constitute RemainderAlloy Silicon Copper Manganese Magnesium Chromium Zinc TitaniumAluminumand OthersWrought Alloys1060 99.60 min.1100a0.12 99.00 min.1350 99.50 min.2319a0.20 5.86.8 0.200.40 0.02 0.10
