1、Designation: A 420/A 420M 07Standard Specification forPiping Fittings of Wrought Carbon Steel and Alloy Steel forLow-Temperature Service1This standard is issued under the fixed designationA 420/A 420M; the number immediately following the designation indicates the yearof original adoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification2covers wrought carbon steel andalloy steel fittings of seamless an
3、d welded construction, cov-ered by the latest revision of ASME B 16.9, ASME B 16.11,MSS-SP-79, MSS-SP-83, and MSS-SP-95. Fittings differingfrom these ASME and MSS standards shall be furnished inaccordance with Supplementary Requirement S58 of Specifi-cation A 960/A 960M. These fittings are for use i
4、n pressurepiping and pressure vessel service at low temperatures.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 ex
5、pressed 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 inch-pound units or SI unitsare to be regarded separately as standard. Wit
6、hin the text, theSI units are shown in brackets. The values stated in eachsystem are not exact equivalents; therefore, each system mustbe used independently of the other.2. Referenced Documents2.1 In addition to those Referenced Documents listed inSpecification A 960/A 960M, the following list of st
7、andardsapply to this specification.2.2 ASTM Standards:3A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 960/A 960M Specification for Common Requirementsfor Wrought Steel Piping Fittings2.3 ASME Standards:B 16.9 Factory-Made Wrought Steel Butt-Welding Fittings4B 16.11 Forge
8、d Steel Fittings, Socket-Welding Threaded4Section VIII Division 1, Pressure Vessels4Section IX Welding Qualifications2.4 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 andTh
9、readed5MSS-SP-95 Swage(d) Nipples and Bull Plugs52.5 ASNT Standards:SNT-TC-1A Recommended Practice for NondestructiveTesting Personnel Qualification and Certification63. Ordering Information3.1 See Specification A 960/A 960M.4. General Requirements4.1 Product furnished to this specification shall co
10、nform tothe requirements of Specification A 960/A 960M, includingany supplementary requirements that are indicated in thepurchase order. Failure to comply with the general require-ments of Specification A 960/A 960M constitutes non-conformance with this specification. In case of conflict be-tween th
11、e requirements of this specification and SpecificationA 960/A 960M, this specification shall prevail.5. Material5.1 The material for fittings shall consist of forgings, bars,plates, seamless or fusion welded tubular products with fillermetal added. It shall conform to the chemical requirements inTab
12、le 1, and be made by one of the following processes:1This 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 BoltingMateria
13、ls for Piping and Special Purpose Applications.Current edition approved March 1, 2007. Published April 2007. Originallyapproved in 1958. Last previous edition approved in 2006 as A 420/A 420M 06.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-420 in Section II of
14、 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 Mechanical Eng
15、ineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.5Available from Manufacturers Standardization Society of the Valve and FittingsIndustry (MSS), 127 Park St., NE, Vienna, VA 22180-4602.6Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28
16、518, 1711 Arlingate Ln., Columbus, OH 43228-0518.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.open-hearth, basic-oxygen, or electric-furnace. The steels shallbe mad
17、e using recognized melting practices necessary toproduce steels that shall meet the impact requirements of thisspecification.6. Manufacture6.1 Forging or forming operations shall be performed byhammering, pressing, piercing, extruding, upsetting, working,bending, fusion-welding, or machining, or by
18、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 tubular products fromwhich fittings are made, shall be (1) made by welders, weldingoperators and welding procedures qu
19、alified 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 each weld in accordancewith Section 14 of this specification. The radiography of weldsshall be done either prior to
20、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 inaccordance with the requirements of Paragraph UW-35 (a) ofSection VIII, Division 1 of ASME Boiler and Pressure Ves
21、selCode.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 RequirementS52 or S53 of Specification A 960/A 960M. This examinationshall be performed after final heat treatment by NDE perso
22、nnelqualified 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 branchoutlet to the centerline of the body or run. Internal and externalsurfaces shall be examined when size permits
23、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 compliance.6.5 Stubends may be produced with the entire lap added bythe welding of a ring, made from plate or bar of
24、 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 qualifications andradiography and 7.1 for post weld heat treatment.7. Heat Treatment7.1 All fittings shall be furni
25、shed 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 thickness of the material from which impact testspecimens are to be obtained shall be heat treated with afurnace charg
26、e 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 the fittings are to be post-weld heat treated afterbeing welded by the purchaser and when so specified in theorder, the
27、 test specimens shall be subjected to the samepost-weld heat treatment. The purchaser shall use the post-weld heat treatment shown in Table 2, unless otherwisespecified in the order.8. Chemical Composition8.1 The steel shall conform to requirements of chemicalcomposition for the respective material
28、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 content.8.3 The chemical composition of weld metal is not
29、 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 similar to that ofthe base metal but shall not exceed 6 % except
30、 in the case offittings of 9 % nickel steel.8.4 A product analysis is optional.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 Cr Mo Cu Cb VWPL6 0.30
31、 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 shall be supplemented by th
32、e 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.TABLE 2 Post-Weld Heat TreatmentGrade Metal Te
33、mperature 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 minWPL9A10251085 550585 1 h/in. 25 mm 2 h minA2 in. 51 mm thickness and over. The cooling rate shall not be less than 300F 150 C per hour down to
34、 a temperature of 600 F 315 C.A 420/A 420M 0729. 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 conditi
35、on 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 one tension test per heat ofweld metal shall be made after heat treatment in the samemanner as the base metal. R
36、esults need not be reported unlessSupplementary Requirement S51 of Specification A 960/A 960M is specified.9.3 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
37、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 equals or exceeds the minimum value permitted for asingle specimen and the value for m
38、ore 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 for each of these retest specimens shall equal orexceed the required average value. Wh
39、en an erratic result iscaused by a defective specimen, or there is uncertainty in testprocedure, a retest shall be allowed.10.2 Procedures:TABLE 3 Tensile RequirementsNOTE 1Where an ellipsis (. . .) appears in this table, there is no requirement.RequirementGradeWPL6 WPL9 WPL3 WPL8Tensile strength, m
40、in 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 specimen, or small proport
41、ional speci-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 % in 2 in. or 50 mm (1
42、2-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) forlongitudinal and 1.0 % (grades WPL6, WPL9 and WPL3) for transverse from the values shown above is permitted. The follow
43、ing table gives the minimum value for variouswall thicknesses: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 28.5 15.5 26.5 17.0 28
44、.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 . . . 19.0 . . . 21.0
45、. . . 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 thickness lies betweentwo va
46、lues 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, %, andt = actual th
47、ickness of specimen, in.A 420/A 420M 07310.2.1 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 upon between the purchaser andproducer and specified
48、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 with Section 18 to identify thereported test temperatu
49、re.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 A 370. Each impact testshall consist of breaking three specimens.10.3 Specimens:10.3.1 Notched-bar impact specimens shall be simple-beam,Charpy-typeAwith a V-notch in accordance with Test Methodsand Definitions A 370. Standard specimens 10 by 10 mm incross section shall be used unless the material to
