1、Designation: A420/A420M 14Standard Specification forPiping Fittings of Wrought Carbon Steel and Alloy Steel forLow-Temperature Service1This standard is issued under the fixed designation A420/A420M; the number immediately following the designation indicates the yearof original adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification2covers wrought carbon steel andalloy steel fittings of seamless and we
3、lded construction, cov-ered by the latest revision of ASME B16.9, ASME B16.11,MSS SP-79, MSS SP-83, MSS SP-95, and MSS SP-97.Fittings differing from these ASME and MSS standards shallbe furnished in accordance with Supplementary RequirementS58 of Specification A960/A960M. These fittings are for use
4、inpressure piping and pressure vessel service at low tempera-tures.1.2 Optional supplementary requirements are provided forfittings where a greater degree of examination is desired. Whendesired, one or more of these supplementary requirements shallbe specified in the order.1.3 This specification is
5、expressed in both inch-pound unitsand in SI units. However, unless the order specifies theapplicable “M” specification designation (SI units), the mate-rial shall be furnished to inch-pound units.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. W
6、ithin the text, theSI units are shown in brackets. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining valuesfrom the two systems may result in non-conformance with thestandard.2. Referenced Documents2.1 In addition
7、to those Referenced Documents listed inSpecification A960/A960M, the following list of standardsapply to this specification.2.2 ASTM Standards:3A960/A960M Specification for Common Requirements forWrought Steel Piping Fittings2.3 ASME Standards:B 16.9 Factory-Made Wrought Steel Butt-Welding Fittings4
8、B 16.11 Forged Steel Fittings, Socket-Welding Threaded4Section VIII Division 1, Pressure Vessels4Section IX2.4 MSS Standards:MSS SP-25 Standard Marking System for Valves, Fittings,Flanges, and Unions5MSS SP-79 Socket Welding Reducer Inserts5MSS SP-83 Steel Pipe Unions, Socket-Welding andThreaded5MSS
9、 SP-95 Swage(d) Nipples and Bull Plugs5MSS SP-97 Integrally Reinforced Forged Branch OutletFittingsSocket Welding, Threaded and ButtweldingEnds2.5 ASNT Standards:SNT-TC-1A Recommended Practice for NondestructiveTesting Personnel Qualification and Certification63. Ordering Information3.1 See Specific
10、ation A960/A960M.4. General Requirements4.1 Product furnished to this specification shall conform tothe requirements of Specification A960/A960M, including anysupplementary requirements that are indicated in the purchaseorder. Failure to comply with the general requirements ofSpecification A960/A960
11、M constitutes non-conformance with1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.22 on Steel Forgings and Wrought Fittings for Piping Applications and BoltingMaterials for Piping and
12、Special Purpose Applications.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 1958. Last previous edition approved in 2013 as A420/A420M13.DOI: 10.1520/A0420_A0420M-14.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-420 in Sect
13、ion II of that Code.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American Society of Mecha
14、nical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.5Available from Manufacturers Standardization Society of the Valve and FittingsIndustry (MSS), 127 Park St., NE, Vienna, VA 22180-4602, http:/www.mss-.6Available fromAmerican Society fo
15、r Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1this spec
16、ification. In case of conflict between the requirementsof this specification and Specification A960/A960M, thisspecification shall prevail.5. Material5.1 The starting material for fittings shall be fully killedsteel, consisting of forgings, bars, plates, sheet, and seamless orfusion welded tubular p
17、roducts with filler metal added andshall conform to the chemical requirements in Table 1. Thesteels shall be made using recognized melting practices neces-sary to produce steels that shall meet the impact requirementsof this specification.6. Manufacture6.1 Forging or forming operations shall be perf
18、ormed byhammering, pressing, piercing, extruding, upsetting, working,bending, fusion-welding, or machining, or by a combination oftwo or more of these operations. The forming procedure shallbe so applied that it will not produce injurious defects in thefittings.6.2 All welds, including welds in tubu
19、lar products fromwhich fittings are made, shall be (1) made by welders, weldingoperators and welding procedures qualified under the provi-sions of ASME Section IX, (2) heat treated in accordance withSection 7 of this specification, and (3) nondestructively exam-ined throughout the entire length of e
20、ach weld in accordancewith Section 15 of this specification. The radiography of weldsshall be done either prior to or after forming at option ofmanufacturer. Personnel performing NDE examinations shallbe qualified in accordance with SNT-TC-1A.6.3 The welded joints of the fittings shall be finished i
21、naccordance with the requirements of Paragraph UW-35 (a) ofSection VIII, Division 1 of ASME Boiler and Pressure VesselCode.6.4 All butt-weld tees manufactured by cold-forming meth-ods shall be liquid penetrant or magnetic particle examined byone of the methods specified in Supplementary RequirementS
22、52 or S53 of Specification A960/A960M. This examinationshall be performed after final heat treatment by NDE personnelqualified under the provisions of SNT-TC-1A. Only the side-wall areas of the tee need be examined. This area is defined bya circle that covers the area from the weld bevel of the bran
23、choutlet to the centerline of the body or run. Internal and externalsurfaces shall be examined when size permits accessibility.After the removal of any cracks, the tees shall be re-examinedby the original method. Acceptable tees shall be marked withthe symbol PT or MT, as applicable, to indicate com
24、pliance.6.5 Stubends may be produced with the entire lap added bythe welding of a ring, made from plate or bar of the same alloygrade and composition, to the outside of a straight section ofpipe, provided the weld is double welded, is a full penetrationjoint, satisfies the requirements of 6.2 for qu
25、alifications andradiography and 7.1 for post weld heat treatment.7. Heat Treatment7.1 All fittings shall be furnished in the normalized, normal-ized and tempered, annealed, or quenched and temperedcondition. All welding shall be completed prior to the austen-itizing heat treatment.7.2 The full thick
26、ness of the material from which impact testspecimens are to be obtained shall be heat treated with afurnace charge as specified in 10.4.2 or 10.4.3.7.3 After forming, the fittings shall be allowed to cool belowthe lower critical before applying one of the heat treatmentslisted in 7.1.7.4 When specif
27、ied in the order, the test specimens shall besubjected to a simulated post-weld heat treatment beforetesting. The simulated post-weld heat treatment used shall beas shown in Table 2, unless the purchaser has otherwisespecified in the order.8. Chemical Composition8.1 The steel shall conform to requir
28、ements of chemicalcomposition for the respective material prescribed in Table 1.8.2 The steel shall not contain any unspecified elements forthe ordered grade to the extent that it then conforms to therequirements of another grade for which that element is aspecified element having a required minimum
29、 content.8.3 The chemical composition of weld metal is not requiredto meet the same limits of the base materials however, thecomposition of the weld deposit shall be such that it meets theminimum mechanical and impact requirements of this specifi-cation. In general, the alloy content shall be simila
30、r to that ofthe base metal but shall not exceed 6 % except in the case offittings of 9 % nickel steel.TABLE 1 Chemical RequirementsNOTE 1All requirements are maximum unless otherwise indicated.NOTE 2Where an ellipsis (.) appears in this table, there is no requirement.GradeAComposition, %CMnP S Si Ni
31、 Cr Mo Cu Cb VWPL6 0.30 0.501.35 0.035 0.040 0.150.40 0.40 0.30 0.12 0.40 0.02B0.08WPL9 0.20 0.401.06 0.030 0.030 . . . 1.602.24 0.751.25WPL3C0.20 0.310.64 0.05 0.05 0.130.37 3.23.8 . . .WPL8D0.13 0.90 0.030 0.030 0.130.37 8.49.6 . . .AWhen fittings are of welded construction, the symbols above shal
32、l be supplemented by the letter “W”.BBy agreement, the limit for Columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.CFittings made from plate or forgings may have 0.90 % max manganese.DFittings made from plate may have 0.98 % max manganese.A420/A420M 1428.4 A pro
33、duct analysis is optional.9. Tensile Properties9.1 The tensile properties of the fittings material shallconform to the requirements for the applicable grade ofmaterial as listed in Table 3.9.2 At least one tension test shall be made on each heat ofmaterial and in the same condition of heat treatment
34、 as thefinished fittings it represents provided that the wall thickness ofthe fitting and the representative sample thickness do not varymore than14 in. 6 mm. At least one tension test per heat ofweld metal shall be made after heat treatment in the samemanner as the base metal. Results need not be r
35、eported unlessSupplementary Requirement S51 of Specification A960/A960M is specified.TABLE 2 Post-Weld Heat TreatmentGrade Metal Temperature Minimum Holding TimeF CWPL6 11001200 595650 1 h/in. 25 mm34 hminWPL3 11001150 54062014 h/in. 25 mm 1 h minWPL8 10501100 56559512 h/in. 25 mm 1 h minWPL9A102510
36、85 550585 1 h/in. 25 mm 2 h minA2 in. 51 mm thickness and over. The cooling rate shall not be less than 300 F150 C per hour down to a temperature of 600 F 315 C.TABLE 3 Tensile RequirementsNOTE 1Where an ellipsis (. . .) appears in this table, there is no requirement.RequirementGradeWPL6 WPL9 WPL3 W
37、PL8Tensile strength, min ksi MPaYield strength, min ksi MPa60 415 95 65535 24063 435 88 61046 31565 450 90 62035 240100 690 125 86575 515Elongation RequirementsGradesWPL6 WPL9 WPL3 WPL8Longi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verseStandard round spec
38、imen, or small proportionalspeci men, min % in 4 D22 12 20 . . . 22 14 16 . . .Rectangular specimen for wall thickness516 in. 7.94mm and over, and for all small sizes tested in fullsection; min % in 2 in. or 50 mm3016.52818302022.Rectangular specimen for wall thickness less than516 in 7.94 mm; min %
39、 in 2 in. or 50 mm (12-in.12.7- mm wide specimen)AAAAAAA.AFor each132 in. 0.79 mm decrease in wall thickness below516 in. 7.94 mm, a deduction of 1.5 % (grades WPL6, WPL9, and WPL3) or 1.25 % (WPL8) for longitudinaland 1.0 % (grades WPL6, WPL9 and WPL3) for transverse from the values shown above is
40、permitted. The following table gives the minimum value for various wallthicknesses:Wall Thickness GradesWPL6 WPL9 WPL3 WPL8in mm Longi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verse516 (0.312) 7.94 30.0 16.5 28.0 18.0 30.0 20.0 22.0 . . .932 (0.281) 7.14 2
41、8.5 15.5 26.5 17.0 28.5 19.0 20.75 . . .14 (0.250) 6.35 27.0 14.5 25.0 16.0 27.0 18.0 19.5 . . .732 (0.219) 5.56 25.5 . . . 23.5 . . . 25.5 . . . 18.25 . . .316 (0.188) 4.76 24.0 . . . 22.0 . . . 24.0 . . . 17.0 . . .532 (0.156) 3.97 22.5 . . . 20.5 . . . 22.5 . . . 15.75 . . .18 (0.125) 3.17 21.0 .
42、 . . 19.0 . . . 21.0 . . . 14.5 . . .332 (0.094) 2.38 19.5 . . . 17.5 . . . 19.5 . . . 13.25 . . .116 (0.062) 1.59 18.0 . . . 16.0 . . . 18.0 . . . 12.0 . . .NoteThe preceding table gives the computed minimum elongation value for each132 in. 0.79 mm decrease in wall thickness. Where the wall thickne
43、ss lies betweentwo values above, the minimum elongation value is determined by the following equations:Direction of Test EquationsWPL6 WPL9 WPL3 WPL8LongitudinalTransverseE = 48t + 15.00t = 32t + 6.5048t + 13.0032t + 8.00E = 48t + 15.00E = 32t + 10.0040t + 9.50.where:E = elongation in 2 in. or 50 mm
44、, %, andt = actual thickness of specimen, in.A420/A420M 1439.3 Records of the tension tests shall be certification that thematerial of the fitting meets the tensile requirements of thisspecification.10. Impact Test Properties10.1 Properties:10.1.1 The notched bar impact properties of the base metala
45、nd weld metal shall conform to the requirements of Table 4 orTable 5 for the applicable grade of material.10.1.2 RetestWhen the average value of the three speci-mens equals or exceeds the minimum value permitted for asingle specimen and the value for more than one specimen isbelow the required avera
46、ge value, or when the value for onespecimen is below the minimum value permitted for a singlespecimen, a retest of three additional specimens shall be made.The value for each of these retest specimens shall equal orexceed the required average value. When an erratic result iscaused by a defective spe
47、cimen, or there is uncertainty in testprocedure, a retest shall be allowed.10.2 Procedures:10.2.1 All material furnished under this specification shallbe tested for impact resistance at the temperature for therespective grade in Table 6. Exceptions to these requirementsare permissible when agreed up
48、on between the purchaser andproducer and specified in the order, in that the impact test isacceptable when made at temperatures different from thoseshown in Table 6, provided the test temperature is at least aslow as the intended service temperature, and fittings aresuitably marked in accordance wit
49、h Section 19 to identify thereported test temperature.10.2.2 The notched-bar impact test shall be made in accor-dance with the procedure for the simple-beam, Charpy-typetest specified in Specification A960/A960M. Each impact testshall consist of breaking three specimens.10.3 Specimens:10.3.1 Notched-bar impact specimens shall be simple-beam,Charpy-type A with a V-notch. Standard specimens 10 by 10mm in cross section shall be used unless the m
