1、Designation: A 758/A 758M 00 (Reapproved 2005)Standard Specification forWrought-Carbon Steel Butt-Welding Piping Fittings withImproved Notch Toughness1This standard is issued under the fixed designationA 758/A 758M; the number immediately following the designation indicates the yearof original adopt
2、ion or, in the 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. Scope1.1 This specification covers wrought-carbon steel butt-welding seamless or
3、welded fittings specially processed toensure better notch toughness than that to be expected infittings manufactured to the requirements of SpecificationA 234/A 234M.1.1.1 Included are elbows, caps, tees, reducers, and othertype fittings covered by ASME B 16.9.1.1.2 Heat treatment is required for al
4、l fittings.1.1.3 Fittings with mandatory radiographic examination ofwelds are included.1.1.4 Supplementary requirements are provided for usewhen additional testing or examination is desired.1.1.5 Cast fittings, and fittings formed from all weld metal,are not included.1.2 Several type of fittings are
5、 provided, as follows:TypeHeat TreatmentRequiredWeld SeamFinish (5.3.2)RadiographyRequired?30 normalize UW-35 no31 normalize UW-35 yes32 normalize UW-35 and ground flush yes40 normalize and temper UW-35 no41 normalize and temper UW-35 yes42 normalize and temper UW-35 and ground flush yes50 quench an
6、d temper UW-35 no51 quench and temper UW-35 yes52 quench and temper UW-35 and ground flush yes1.3 It shall be the responsibility of the purchaser to deter-mine whether material meeting the requirements of this speci-fication is satisfactory for the service application.1.4 This specification is expre
7、ssed in both inch-pound unitsand SI units. However, unless the order specifies the applicable“M” specification designation (SI units), the material shall befurnished to inch-pound units.1.5 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the
8、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. Combining values from thetwo systems may result in nonconformance with the specifi-cation.2. Referenced Documents2.1 In addition to those
9、 reference documents listed inSpecification A 960/A 960M, the following list of standardsapply to this specification:2.2 ASTM Standards:2A 234/A 234M Specification for Piping Fittings of WroughtCarbon Steel and Alloy Steel for Moderate and ElevatedTemperaturesA 275/A 275M Test Method for Magnetic Pa
10、rticle Exami-nation of Steel ForgingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 960/A 960M Specification for Common Requirementsfor Wrought Steel Piping FittingsE 165 Test Method for Liquid Penetrant Inspection MethodE 709 Guide for Magnetic Particle Examination2.3 A
11、SME Boiler and Pressure Vessel Code (ASME Code):3Section VIII, Division 1 Pressure VesselsSection IX , Welding and Brazing Qualifications2.4 ASME Standard:B 16.9 Standards for Steel Butt-Welding Fittings32.5 ASNT Standard:SNT-TC-1A Practice for Nondestructive Examination Per-sonnel Qualification and
12、 Certification43. Ordering Information3.1 See Specification A 960/A 960M.4. General Requirements4.1 Product furnished to this specification shall conform tothe requirements of Specification A 960/A 960M, including1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless
13、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 edition approved Sept. 10, 2000. Published December 2000. Originallyapproved in 19
14、78. Last previous edition approved in 1998 as A 758/A 758M 98.2For 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
15、.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.4Available from TheAmerican Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.1Copyright ASTM International,
16、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.any supplementary requirements that are indicated in thepurchase order. Failure to comply with the requirements ofSpecification A 960/A 960M constitutes non-conformancewith this specification. In case of a conflict b
17、etween therequirements of this specification and Specification A 960/A 960M, this specification shall prevail.5. Materials and Manufacture5.1 The steel shall be killed and shall be melted to a fineaustenitic grain size practice.5.2 The starting material shall be wrought and in the form ofblooms, bil
18、lets, slabs, forgings, bars, plates, sheets, seamlesspipe or tube, or welded-with-filler-metal pipe or tube. Castproducts shall not be used.5.3 Any forming process, fusion-welding process, or com-bination of such processes, may be used.5.3.1 All welding shall be fusion-welded in accordance withthe r
19、equirements of Section IX of the ASME Boiler andPressure Vessel Code. Welding procedures, welders, and weld-ing operators shall be qualified in accordance with Section IXof the ASME Boiler and Pressure Vessel Code.5.3.2 All welded joints shall be finished in accordance withParagraph UW-35 of Section
20、 VIII, Division 1, of the ASMECode.5.3.3 Welded joints of Type 32, 42, and 52 shall be groundflush.5.3.4 Welded joints of Types 31, 41, 51, 32, 42, and 52 shallbe examined by radiography in accordance with the require-ments of Paragraph UW-51 of Section VIII, Division 1,oftheASME Code, and shall con
21、form to the requirements ofParagraph UW-51.5.4 Heat TreatmentAll fittings shall be heat treated sub-sequent to final welding and forming.5.4.1 Types 30, 31, and 32 fittings shall be normalized byuniformly heating to a temperature in the austenitizing range,but not to exceed 1700 F 925 C, and subsequ
22、ently removedfrom the furnace and air-cooled individually to room tempera-ture.5.4.2 Types 40, 41, and 42 fittings shall be normalized inaccordance with 5.4.1. After normalizing, the fittings shall betempered by heating to a temperature in the range from 1100 Fto 1200 F 595 C to 675 C, soaking at th
23、at temperature for12 h minimum per 1 in. 25 mm of thickness, but not less than15 min, and then air-cooled to room temperature.5.4.3 Types 50, 51, and 52 fittings shall be quenched-and-tempered by uniformly heating to a temperature in the auste-nitizing range, but not to exceed 1700 F 925 C, and then
24、quenching in a liquid media from the austenitizing temperatureto a temperature below 800 F 425 C. After quenching, thefittings shall be reheated to a temperature in the range from1100 F to 1250 F 595 C to 675 C, soaking at thattemperature for12 h minimum per 1 in. 25 mm of thickness,but not less tha
25、n 15 min, and then air-cooled to roomtemperature.6. Chemical Composition6.1 Heat or Cast Analysis The results shall conform to therequirements for the applicable grade as specified in Table 1.6.2 ProductAnalysisProduct analysis may be made by thepurchaser. The results shall conform to the requiremen
26、ts for theapplicable grade as specified in Table 1.6.3 The steel shall not contain any unspecified elements forthe ordered grade to the extent that it conforms to therequirements of another grade for which that element is aspecified element having a required minimum content.7. Mechanical Requirement
27、s Mechanical Requirements7.1 Tensile Requirements:7.1.1 The fittings, as represented by tensile test specimenstaken subsequent to final heat treatment, shall conform to therequirements for the applicable grade as specified in Table 2.7.1.2 Number and Location of Specimens:7.1.2.1 LotFor tension test
28、ing, a lot shall consist of thefittings from a heat, in each heat treatment charge, withnominal wall thicknesses within14 in. 6 mm of the nominalthickness of the test specimen. In addition, for Types 32, 42,and 52, the lot definition shall include each heat or lot of weldmetal. If heat treatment is
29、performed in a continuous orbatch-type furnace controlled within a range of plus-or-minus25 F 14 C and equipped with calibrated thermocouples andrecording pyrometers, and records of heat treatment are main-tained, all fittings heat treated in such a furnace are consideredto be in one charge. For fur
30、naces not so equipped andcontrolled, each batch constitutes a charge.7.1.2.2 Representative Test PieceFor instances in whichthe tension test specimen cannot be obtained from a fitting dueto size limitations, a representative test piece may be used. Thetest piece shall be from the same heat and shall
31、 be heat treatedTABLE 1 Chemical RequirementsElement Cast or HeatAnalysisProductAnalysisCarbon, max, % 0.27 0.30Manganese, % 0.851.20 0.751.25Phosphorus, max, % 0.035 0.040Sulfur, max, % 0.035 0.040Silicon, % 0.150.30 0.130.33Vanadium, max, % 0.05 0.05Residual elementsA,BChromium, max, % 0.25 0.25Ni
32、ckel, max, % 0.25 0.25Molybdenum, max, % 0.08 0.08Copper, max, % 0.35 0.35Lead, max, % 0.05 0.05AIndividual limits of chromium, nickel, molybdenum, and copper may beexceeded by 0.05 % provided that their total does not exceed 0.90 % in both theheat and product analysis.BThese are not to be added to
33、the melt and shall only occur as a result ofunavoidable residuals from the melting stock.TABLE 2 Tensile RequirementsGrade 60 Grade 70Tensile strength, ksi MPa 60 to 85 415 to 585 70 to 95 485 to 635Yield strength,Amin, ksiMPa35 240 38 260Elongation in 2 in. 50 mm,min, %Longitudinal 30 27Transverse
34、22 20A0.2 % offset or 0.5 % EUL.A 758/A 758M 00 (2005)2in the same heat treatment batch or charge as the fittings itrepresents, and shall have had approximately the same amountof working as the fittings. In addition, for fittings manufacturedfrom bars, plate, or forgings, the test piece shall have a
35、cross-section equal to or larger than the greatest cross-sectionof the fittings it represents. Test pieces representing fittingsmanufactured from pipe shall have a nominal outside diameterand wall thickness equal to that of the pipe from which thefitting was formed. Test pieces for fittings fabricat
36、ed bywelding or formed from welded pipe shall be prepared with thesame welding procedure and from the same heat or lot of weldmetal as the fitting it represents.7.1.2.3 Types 30, 31, 40, 41, 50, and 51 One base-metaltension test specimen shall be tested from each lot. For fittingsfabricated by weldi
37、ng, one transverse-weld tension test speci-men shall also be made from each lot. One traverse-weldtension test specimen shall also be required from each lot forfittings formed from welded pipe if the weld in the welded pipewas not tested in the same heat treatment condition as thefittings.7.1.2.4 Ty
38、pes 32, 42, and 52One base-metal and onetransverse-weld tension test specimen shall be tested from eachlot. Fittings fabricated by welding or formed from welded pipeshall be tested as in 7.1.2.3.7.1.2.5 Tension test specimens shall be taken from anintegral part of the fitting where practicable. All
39、base-metaltension tests shall be conducted in the longitudinal direction.Weld metal specimens shall be taken transverse to the weld.7.1.2.6 Tests shall be conducted in accordance with TestMethods and Definitions A 370. Yield strength shall be deter-mined either by the 0.2 % offset method or the 0.5
40、%extension-under-load method.7.2 Transverse Guided Weld Bend TestsWelded FittingsOnly:7.2.1 Number of Tests:7.2.1.1 LotA lot shall be as defined in 7.1.2.1.7.2.1.2 One guided face-bend and one guided root-bend testshall be made to represent each lot for fittings with a nominalwall thickness of38 in.
41、 10 mm and less. For fittings with anominal wall thickness greater than38 in. 10 mm, one guidedside-bend test shall be made to represent each lot.7.2.2 Test Specimen Location and OrientationFull thick-ness specimens shall be taken transverse to the weld, subse-quent to final heat treatment, in accor
42、dance with Section IX ofthe ASME Boiler and Pressure Vessel Code.7.2.3 RequirementThe guided-bend test specimen shallnot have any cracks or other open defects exceeding18 in. 3mm, measured in any direction on the convex surface of thespecimen after bending. Cracks occurring on the corners of thespec
43、imen during testing shall not be considered unless there isdefinite evidence that they result from slag inclusions or otherinternal defects.8. Dimensions8.1 Butt-welded fittings shall conform to the dimensionsand tolerances specified in ASME B 16.9.9. Surface Quality9.1 See Specification A 960/A 960
44、M.10. Radiographic Examination10.1 Types 31, 32, 41, 42, 51, and 52 fittings shall have theentire length of each weld joint examined radiographically inaccordance with Paragraph UW-51 of Section VIII, Division 1,of the ASME Boiler and Pressure Vessel Code.10.2 Radiographic examination may be perform
45、ed prior tofinal heat treatment.10.3 Personnel performing radiographic examination shallbe qualified and certified in accordance with SNT-TC-1A-1984, or with the approval of the purchaser, in accordance withanother nationally-accepted standard which covers the qualifi-cation and certification of rad
46、iographic examination personnel.11. Rework and Retreatment11.1 See Specification A 960/A 960M.11.2 Repair WeldingParent Metal:11.2.1 Repair welding by the manufacturer is permissiblefor parts made to dimensional standards, in ASME or equiva-lent standards.11.2.2 Prior approval of the purchaser shall
47、 be required toweld repair special parts made to the purchasers requirements.11.2.3 Welding shall produce low hydrogen in the weld-ment.11.2.4 The product shall be heat treated in accordance withSection 5 after weld repair.12. Inspection12.1 The manufacturer shall afford the purchasers inspec-tors a
48、ll reasonable facilities necessary to satisfy him that thematerial is being produced and furnished in accordance withthis specification. Inspection by the purchaser shall not inter-fere unnecessarily with the manufacturers operations. All testsand inspections shall be made at the place of manufactur
49、e,unless otherwise agreed to.13. Rejection and Rehearing13.1 Material that fails to conform to the requirements ofthis specification may be rejected. Rejection should be reportedto the producer or supplier promptly and in writing. In case ofdissatisfaction with the results of the test, the producer orsupplier may make claim for a rehearing.13.2 Fittings that develop defects in shop working orapplication operations may be rejected. Upon rejection, themanufacturer shall be notified in writing.14. Certificati
