1、Designation: A420/A420M 16Standard 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:3A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA960/A960M Specification for Common Requirements forWrought Steel Piping FittingsA1
8、058 Test Methods for Mechanical Testing of SteelProductsMetric2.3 ASME Standards:B 16.9 Factory-Made Wrought Steel Butt-Welding Fittings4B 16.11 Forged Steel Fittings, Socket-Welding Threaded4Section VIII Division 1, Pressure Vessels4Section IX2.4 MSS Standards:MSS SP-25 Standard Marking System for
9、Valves, Fittings,Flanges, and Unions5MSS SP-79 Socket Welding Reducer Inserts5MSS SP-83 Steel Pipe Unions, Socket-Welding andThreaded5MSS SP-95 Swage(d) Nipples and Bull Plugs5MSS SP-97 Integrally Reinforced Forged Branch OutletFittingsSocket Welding, Threaded and ButtweldingEnds2.5 ASNT Standards:S
10、NT-TC-1A Recommended Practice for NondestructiveTesting Personnel Qualification and Certification63. Ordering Information3.1 See Specification A960/A960M.4. General Requirements4.1 Product furnished to this specification shall conform tothe requirements of Specification A960/A960M, including any1Thi
11、s 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 Special Purpose Applications.Current e
12、dition approved May 1, 2016. Published May 2016. Originallyapproved in 1958. Last previous edition approved in 2014 as A420/A420M 14.DOI: 10.1520/A0420_A0420M-16.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-420 in Section II of that Code.3For referenced ASTM s
13、tandards, 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 Mechanical Engineers (ASME), ASMEInternational
14、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 for Nondestructive Testing (ASNT), P.O. Box2
15、8518, 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 States1supplementary requirements that are indicated in th
16、e purchaseorder. Failure to comply with the general requirements ofSpecification A960/A960M constitutes non-conformance withthis specification. In case of conflict between the requirementsof this specification and Specification A960/A960M, thisspecification shall prevail.5. Material5.1 The starting
17、material for fittings shall be fully killedsteel, consisting of forgings, bars, plates, sheet, and seamless orfusion welded tubular products with filler metal added andshall conform to the chemical requirements in Table 1. Thesteels shall be made using recognized melting practices neces-sary to prod
18、uce steels that shall meet the impact requirementsof this specification.6. Manufacture6.1 Forging or forming operations shall be performed byhammering, pressing, piercing, extruding, upsetting, working,bending, fusion-welding, or machining, or by a combination oftwo or more of these operations. The
19、forming procedure shallbe so applied that it will not produce injurious defects in thefittings.6.2 All welds, including welds in tubular 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)
20、 heat treated in accordance withSection 7 of this specification, and (3) nondestructively exam-ined throughout the entire length of each weld in accordancewith Section 15 of this specification. The radiography of weldsshall be done either prior to or after forming at option ofmanufacturer. Personnel
21、 performing NDE examinations shallbe qualified in accordance with SNT-TC-1A.6.3 The welded joints of the fittings shall be finished inaccordance 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-
22、forming meth-ods shall be liquid penetrant or magnetic particle examined byone of the methods specified in Supplementary RequirementS52 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
23、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 branchoutlet 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 tee
24、s shall be re-examinedby the original method. Acceptable tees shall be marked withthe symbol PT or MT, as applicable, to indicate compliance.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 o
25、f a straight section ofpipe, provided the weld is double welded, is a full penetrationjoint, satisfies the requirements of 6.2 for qualifications 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, anne
26、aled, or quenched and temperedcondition. All welding shall be completed prior to the austen-itizing heat treatment.7.2 The full thickness 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,
27、the fittings shall be allowed to cool belowthe lower critical before applying one of the heat treatmentslisted in 7.1.7.4 When specified 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 sh
28、own in Table 2, unless the purchaser has otherwisespecified in the order.8. Chemical Composition8.1 The steel shall conform to requirements 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 ex
29、tent that it then conforms to therequirements of another grade for which that element is aspecified element having a required minimum 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 s
30、uch that it meets theTABLE 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 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.
31、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 shall be supplemented by the letter “W”.BBy agreement, the limit for Columbium may be
32、 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 162minimum mechanical and impact requirements of this specifi-cation. In general, the alloy c
33、ontent shall be similar to that ofthe base metal but shall not exceed 6 % except in the case offittings of 9 % nickel steel.8.4 A product analysis is optional.9. Tensile Properties9.1 The tensile properties of the fittings material shallconform to the requirements for the applicable grade ofmaterial
34、 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 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
35、 one tension test per heat ofweld metal shall be made after heat treatment in the samemanner as the base metal. Results need not be reported unlessSupplementary Requirement S51 of Specification A960/A960M is specified.TABLE 2 Post-Weld Heat TreatmentGrade Metal Temperature Minimum Holding TimeF CWPL
36、6 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 minWPL9A10251085 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
37、3 Tensile RequirementsNOTE 1Where an ellipsis (. . .) appears in this table, there is no requirement.RequirementGradeWPL6 WPL9 WPL3 WPL8Tensile strength, min ksi MPaYield strength, min ksi MPa60 415 95 65535 24063 435 88 61046 31565 450 90 62035 240100 690 125 86575 515Elongation RequirementsGradesW
38、PL6 WPL9 WPL3 WPL8Longi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verseLongi-tudinalTrans-verseStandard round specimen, or small proportionalspecimen, min % in 4 D22 12 20 . . . 22 14 16 . . .Rectangular specimen for wall thickness516 in. 7.94mm and over, and for all small sizes t
39、ested in fullsection; min % in 2 in. or 50 mm3016.52818302022.Rectangular specimen for wall thickness less than516 in 7.94 mm; min % 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, WP
40、L9, and WPL3) or 1.25 % (WPL8) for longitudinaland 1.0 % (grades WPL6, WPL9 and WPL3) for transverse from the values shown above is permitted. The following table gives the minimum value for various wallthicknesses:Wall Thickness GradesWPL6 WPL9 WPL3 WPL8in. mm Longi-tudinalTrans-verseLongi-tudinalT
41、rans-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 28.5 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
42、) 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 . . . 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 p
43、receding table gives the computed minimum elongation value for each132 in. 0.79 mm decrease in wall thickness. Where the wall thickness lies betweentwo values above, the minimum elongation value is determined by the following equations:Direction of Test EquationsWPL6 WPL9 WPL3 WPL8LongitudinalTransv
44、erseE = 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, %, andt = actual thickness of specimen, in.A420/A420M 1639.3 Records of the tension tests shall be certification that thematerial of the fitting meets the tensile re
45、quirements of thisspecification.10. Impact Test Properties10.1 Properties:10.1.1 The notched bar impact properties of the base metaland 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 e
46、quals or exceeds the minimum value permitted for asingle specimen and the value for more than one specimen isbelow the required average 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 f
47、or each of these retest specimens shall equal orexceed the required average value. When an erratic result iscaused by a defective specimen, 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 im
48、pact resistance at the temperature for therespective grade in Table 6. Exceptions to these requirementsare permissible when agreed upon 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, p
49、rovided the test temperature is at least aslow as the intended service temperature, and fittings aresuitably marked in accordance with 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 of Test Methods and Definitions A370 if the inch-poundunits are specified or Test Methods A1058 if the M suffix (SIunits) standard is spe
