1、Guide forWeldingFerritic/AusteniticDuplex StainlessSteel Piping andTubingAWS D10.18M/D10.18:2008An American National Standard550 N.W. LeJeune Road, Miami, FL 33126AWS D10.18M/D10.18:2008An American National StandardApproved by theAmerican National Standards InstituteJanuary 23, 2008Guide for Welding
2、Ferritic/Austenitic DuplexStainless Steel Piping and Tubing1st EditionPrepared by theAmerican Welding Society (AWS) D10 Committee on Piping and TubingUnder the Direction of theAWS Technical Activities CommitteeApproved by theAWS Board of DirectorsAbstractThis standard presents a detailed discussion
3、of the metallurgical and welding characteristics and weldability of duplexstainless steel used in piping and tubing. A number of tables and graphs are presented in order to illustrate the text.iiAWS D10.18M/D10.18:2008International Standard Book Number: 978-0-87171-088-8American Welding Society550 N
4、.W. LeJeune Road, Miami, FL 33126 2008 by American Welding SocietyAll rights reservedPrinted in the United States of AmericaPhotocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in anyform, including mechanical, photocopying, recording, or othe
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6、propriatefee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet:.iiiAWS D10.18M/D10.18:2008Statement on the Use of American Welding Society StandardsAll standards (codes, specifications, recommended practices, methods, classifications, and
7、 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 fe
8、deral 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 par
9、t 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 cont
10、racting 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 the AWS administers theprocess and establishes rules to promote fairness in the deve
11、lopment 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.AWS disclaims liability for any injury to persons or to property, or other damages of any nature whatsoever, whetherspecial, indirec
12、t, consequential, or compensatory, directly or indirectly resulting from the publication, use of, or relianceon this standard. AWS also makes no guarantee or warranty as to the accuracy or completeness of any informationpublished herein.In issuing and making this standard available, AWS is neither u
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16、 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 power to do so.On occasion, text, tables, or figures are printed incorrectly, constituting errata. Such errata, when discovered, are p
17、ostedon 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 Di
18、rector, Technical Services Division, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex A).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 con
19、stitute 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 inf
20、ormal 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 Tubing. It must be reviewedevery five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations, a
21、dditions, 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 receive careful consideration by the AWS D10 Committee on Piping andTubing and the author of the comments will be informed of the Co
22、mmittees 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 for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation ofthe Technical Activities Com
23、mittee. 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 D10.18M/D10.18:2008vAWS D10.18M/D10.18:2008PersonnelAWS D10 Committee on Piping and TubingM. P. Lang, Chair United Association, Local 501W. F.
24、 Newell, Vice Chair W. F. Newell therefore, each system must be usedindependently.To identify nominal pipe sizes in both SI and U.S.Customary Units, the following designations are used:(1) DN (Diameter Nominal) is the SI designation, and(2) NPS (Nominal Pipe Size) is the U.S. Customarydesignation.Sa
25、fety 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 AlliedProcesses, and applicable federal and
26、 state regulations.2. Normative ReferencesThe following standards contain provisions which,through reference in this text, constitute mandatory pro-visions of this AWS guide. For undated references, thelatest edition of the referenced standard shall apply. Fordated references, subsequent amendments
27、to, or revi-sions of, any of these publications do not apply.AWS A3.0, Standard Welding Terms and Definitions,Including Terms for Adhesive Bonding, Brazing, Solder-ing, Thermal Cutting, and Thermal Spraying.13. Terms and DefinitionsTerms used in this document should be interpreted inaccordance with
28、AWS A3.0, Standard Welding Termsand Definitions, except for those not defined by thatstandard or where these terms require further definitionto clarify their usage in this standard.orbital welding. Automatic or mechanized welding oftube or pipe in which a welding arc rotates (orbits)around a station
29、ary weld joint.4. Material Compositions and Specifications4.1 Material Compositions. The duplex stainless steels(DSSs) have a microstructure of approximately equalparts of ferrite and austenite, consequently in the weldingand fabrication, the duplex alloys exhibit some charac-teristics of both ferri
30、tic and austenitic stainless steels. Asa result, the welding procedures for the duplex alloysrequire different parameters than ferritic or austeniticstainless steels.Attractive features of DSSs include a yield strengthabout double that of the austenitic grades, while main-taining ductility and tough
31、ness approaching that of theaustenitics. DSSs are especially resistant to chloride1AWS standards are published by the American WeldingSociety, 550 N.W. LeJeune Road, Miami, FL 33126.Guide for Welding Ferritic/AusteniticDuplex Stainless Steel Piping and TubingAWS D10.18M/D10.18:20082stress corrosion
32、cracking, pitting, crevice corrosion anderosion corrosion. The useful service temperature rangeis more restricted than the austenitics and varies with theparticular duplex alloy. In general, the duplex range is 40C 40F to 280C 535F.4.2 Specifications. The wrought DSSs are often classi-fied into thre
33、e families based on composition. The com-positions of the wrought alloy families are shown inTables 1, 2, and 3. Cast alloys are shown in Table 4.Type 2205 is the most widely used of the DSSs and isestimated to represent 80% of DSSs used. Most literaturereferences to welding DSSs refer to 2205, howe
34、verdetails of welding procedures for the three groups arediscussed in later subclauses.Common duplex stainless steel specifications for pipeand tubing, fittings, and castings are as follows:(1) ASTM A 351, Castings, Austenitic-Ferritic(Duplex), for Pressure-Containing Parts; StandardSpecification fo
35、r;(2) ASTM A 380, Cleaning, and Descaling StainlessSteel Parts, Equipment and Systems; Standard Recom-mended Practice for;(3) ASTM A 789, Seamless Welded Ferritic/Austen-itic Stainless Steel Tubing for General Service; StandardSpecification for;(4) ASTM A 790, Seamless and Welded Ferritic/Austenitic
36、 Stainless Steel Pipe; Standard Specificationfor;(5) ASTM A 815, Wrought Ferritic, Ferritic/Austen-itic, and Martensitic Stainless Steel Piping Fittings;Standard Specification for;(6) ASTM A 890, Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex (Austenitic/Ferritic) for General
37、Applications; Standard Specificationfor;(7) ASTM A 923, Detecting Detrimental IntermetallicPhase in Wrought Duplex Austenitic/Ferritic StainlessSteels; Standard Test Methods for;Table 1Chemical Composition by Weight Percentaof Wrought Lean Duplex Stainless SteelsCommonNameUNS Number C N Cr Ni Mo P S
38、 Si Mn OtherLDX 2101 S32101 0.04 0.200.25 21.022.0 1.351.70 0.100.80 0.040 0.030 1.00 4.06.0 Cu0.100.802304 S32304 0.03 0.050.20 21.524.5 3.05.5 0.050.60 0.040 0.040 1.00 2.50 Cu0.050.602003 S32003 0.03 0.140.20 19.522.5 3.04.0 1.52.0 0.030 0.020 1.00 2.00 aSingle values are maximums.Table 2Chemical
39、 Composition by Weight Percentaof Standard Duplex Stainless SteelsCommon NameUNS Number C N Cr Ni Mo P S Si Mn Other2205bS32205 0.03 0.140.20 22.023.0 4.56.5 3.003.50 0.030 0.020 1.00 2.00 255 S32550 0.04 0.100.25 24.027.0 4.56.5 2.93.9 0.040 0.030 1.00 1.50 Cu1.52.5Cr-Ni-Mo-N S32950 0.03 0.150.35 2
40、6.029.0 3.505.20 1.002.50 0.035 0.010 0.60 2.00 aSingle values are maximums.bThere is an older UNS version of alloy 2205, UNS S31803. This older version has been replaced by S32205, but some references may still be madeto S31803. S32205 has higher chromium, molybdenum and nitrogen content. Higher le
41、vels of nitrogen reduce the tendency to form excess ferriteleading to poor heat-affected zone (HAZ) mechanical properties (toughness). Higher levels of all three elements improve corrosion resistance.AWS D10.18M/D10.18:20083(8) ASTM A 928, Ferritic/Austenitic (Duplex) Stain-less Steel Pipe Electric
42、Fusion Welded with Addition ofFiller Metal; Standard Specification for; and(9) ASTM A 995, Castings, Austenitic-Ferritic(Duplex) Stainless Steel, for Pressure-Containing Parts;Standard Specification for.5. Basic Metallurgy5.1 Solidification and Ferrite/Austenite Phases. AllDSSs solidify as ferrite w
43、hether solidification is in aningot, casting, or a weld. Islands of austenite form in theferrite matrix down to a temperature of about 1000C1832F. When wrought products are hot worked, theaustenite phase typically assumes an elongated morphol-ogy such as shown on Figure 1, a cross section ofan alloy
44、 2205 plate. The austenite phase is the lighterconstituent in the darker ferrite matrix.The preferred amount of ferrite is 40% to 60%, althoughthe range may be expanded somewhat depending uponthe application. When there is a high level of ferrite,toughness and ductility are reduced while at high lev
45、elsof austenite, resistance to stress corrosion cracking isreduced and mechanical properties may be somewhatreduced. It is generally accepted that as long as there is atleast 25% of the lesser phase, the expected properties ofthe duplex alloy will be realized.In mill or wrought product forms, the am
46、ount of ferriteand austenite depends upon the composition and thethermal history. Elements that mainly influence phaseTable 3Chemical Composition by Weight Percentaof Super Duplex Stainless SteelsCommon NameUNS Number C N Cr Ni Mo P S Si Mn Other2507 S32750 0.03 0.240.32 24.026.0 6.08.0 3.05.0 0.035
47、 0.020 0.8 1.20 Zeron100 S32760 0.03 0.20.3 24.026.0 6.08.0 3.04.0 0.030 0.010 1.0 1.00 Cub0.51.0bWb0.51.0baSingle values are maximums.bOther: %Cr + 3.3 %Mo + 16 %N 40.Table 4Chemical Composition by Weight Percentaof Cast Duplex Stainless SteelsACI DesignationWrought EquivalentUNS Number C N Cr Ni M
48、o P S Si Mn OtherCD4MCu J93370 0.04 24.526.5 4.756.00 1.752.25 0.040 0.040 1.0 1.0 Cu2.753.25CD4MCuN S32550 J93372 0.04 0.100.25 24.526.5 4.76.0 1.72.3 0.040 0.040 1.00 1.0 Cu2.73.3CD3MN 2205 J92205 0.03 0.100.30 21.023.5 4.56.5 2.53.5 0.040 0.0200 1.0 1.5 Cu1.0CE3MN 2507 J93404 0.03 0.100.30 24.026
49、.0 6.08.0 4.05.0 1.0 1.5 Note bCD3MWCuN Zeron100 J93380 0.03 0.200.30 24.026.0 6.58.5 3.04.0 0.030 0.025 1.0 1.0 Wb0.51.0baSingle values are maximums.bOther: %Cr + 3.3 %Mo + 16 %N 40.AWS D10.18M/D10.18:20084balance are chromium, molybdenum, nickel, and nitro-gen. Thermal processing employed by the mills includefactors such as hot working temperature and coolingrates, both of which can vary depending on the particularproduct being produced.Weld ferrite measurements can be made using eitherdestr
