1、Designation: A 1048/A 1048M 06Standard Specification forPressure Vessel Forgings, Alloy Steel, Higher StrengthChromium-Molybdenum-Tungsten for Elevated TemperatureService1This standard is issued under the fixed designation A 1048/A 1048M; the number immediately following the designation indicates th
2、eyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers chromium-molybdenum-tun
3、gsten alloy steel forgings intended primarily for use inboilers and pressure vessels for elevated temperature service.1.1.1 Elevated temperatures are temperatures in the rangewhere creep and stress rupture properties are important for thealloy steels in this specification.1.2 Supplementary requireme
4、nts are provided both in thisspecification and in the General Requirements SpecificationA 788/A 788M for use when additional testing or inspection isdesired. These shall apply only when specified individually bythe purchaser in the purchase order or contract.1.3 Unless the order specifies the applic
5、able “M” specifica-tion designation, the forgings shall be supplied to the inch-pound units.1.4 The values stated in either inch-pound or SI (metric)units are to be regarded separately as standard. Within the textand tables, the SI units are shown in brackets. The values statedin each system may not
6、 be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the specification.2. Referenced Documents2.1 ASTM Standards:2A 275/A 275M Test Method for Magnetic Particle Exami-nation of Steel ForgingsA 388
7、/A 388M Practice for Ultrasonic Examination ofHeavy Steel ForgingsA 788/A 788M Specification for Steel Forgings, GeneralRequirementsA 966/A 966M Test Method for Magnetic Particle Exami-nation of Steel Forgings Using Alternating Current3. Ordering Information and General Requirements3.1 In addition t
8、o the ordering information required bySpecification A 788/A 788M, the purchaser should includewith the inquiry and order the following information:3.1.1 A drawing, sketch, or written description of therequired forging and the manner of providing test material (seeSection 6).3.1.2 Desired supplementa
9、ry requirements including thosefrom Specification A 788/A 788M.3.1.3 Requirements for alternate ultrasonic examinationprocedure (see 7.1.2).3.1.4 At the purchasers option Test Method A 966/A 966Mshall be used for the magnetic particle examination.3.2 Forgings supplied to this specification shall con
10、form tothe requirements of Specification A 788/A 788M which, inaddition to ordering information, includes manufacturing re-quirements, testing and retesting methods and procedures,marking, certification, product analysis variations and addi-tional supplementary requirements.3.3 If the requirements o
11、f this specification are in conflictwith those of SpecificationA 788/A 788M, the requirements ofthis specification shall prevail.4. Materials and Manufacture4.1 The steel melting procedures of Specification A 788/A 788M shall apply except that the open hearth process shallnot be used, and that the m
12、olten steel shall be vacuum degassedprior to or during teeming of the ingot to remove objectionablegasses, notably hydrogen.4.2 Heat Treatment:4.2.1 After being permitted to transform following comple-tion of forging the material may be given an intermediate heattreatment such as normalizing and tem
13、pering or a subcriticalanneal prior to preliminary machining to the required heattreatment contour. The purchaser may specify supplementaryrequirement S1 to have the forgings rough machined before thefinal heat treatment.4.2.2 Heat treatment applied either after rough machining ordirectly after cool
14、ing from forging shall consist of normalizingand tempering as follows:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Sept. 1,
15、 2006. Published September 2006.2For 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.1Copyright ASTM International
16、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Normalize from 1950 to 2050F 1065 to 1120CTemper at 1290 to 1400F 700 to 760C4.2.3 Multiple normalize or temper cycles, or both, may beapplied providing the final stages comply with the temperaturesshown in 4.2.2.5
17、. Chemical Composition5.1 Heat AnalysisThe heat analysis obtained fromsamples taken in accordance with Specification A 788/A 788Mshall comply with Table 1.5.2 The manufacturer shall use the product analysis provi-sions of Specification A 788/A 788M to obtain a productanalysis from a forging represen
18、ting each heat or multiple heat.The purchaser may also make this determination in accordancewith Specification A 788/A 788M.6. Mechanical Properties6.1 Tension and Charpy impact test specimens shall beoriented in the longitudinal direction, that is, with their majoraxes parallel to the direction of
19、maximum working.6.2 Both the tensile and Charpy impact specimens shall belocated at the mid-radius or14 thickness location in the integraltest prolongation or, if applicable (see 6.4), in the test forging.6.3 The integral test prolongation or prolongations shall beno smaller in diameter or effective
20、 section thickness than themaximum diameter or cross section of the connected forging.6.4 For forgings weighing 5000 lb 2250 kg or less at thetime of heat treatment, a separately forged test bar may be usedto provide material for mechanical testing.6.4.1 The heat-treated diameter or section thicknes
21、s of thetest forging must be at least equal to the heat-treated diameteror effective section of the forgings it represents.6.4.2 One test forging, yielding one tension test and aCharpy impact test (consisting of three specimens) is requiredto represent each heat in each heat treatment charge.6.5 For
22、 heat-treated weights over 5000 lb 2250 kg but notmore than 10 000 lb 4500 kg an integral prolongation isrequired at one end of each forging. One tension test and oneCharpy test (three specimens) is required for each forging.6.6 For heat-treated weights over 10 000 lb 4500 kg andheat-treated lengths
23、 up to 10 ft 3 m, excluding the testprolongation, two sets of mechanical test specimens shall betaken from an integral prolongation at one end of each forging.These sets shall be located 180 apart and each set shall consistof one tension test and a Charpy test.6.6.1 For heat-treated weights over 10
24、000 lb 4500 kg andheat-treated lengths over 10 ft 3 m, a test prolongation isrequired to be located at each end of the forging. One set ofmechanical test specimens shall be taken from each prolonga-tion, and each test set shall consist of one tension test and aCharpy test.6.7 The tension and Charpy
25、test results shall conform to therequirements of Tables 2 and 3, respectively.7. Nondestructive Examination7.1 Ultrasonic Examination:7.1.1 Forgings shall undergo ultrasonic examination in ac-cordance with the procedures of Practice A 388/A 388M.7.1.2 Straight-Beam ExaminationUnless otherwise speci-
26、fied by the purchaser (see 3.1.3) back-reflection method shallbe used.7.1.3 In addition to the reportable conditions referenced inPractice A 388/A 388M indications exceeding the resultantback-reflection shall be recorded.7.1.4 Aforging shall be considered to be unacceptable whenone or more reflectio
27、ns are present producing indicationsaccompanied by a complete loss of back-reflection, not attrib-utable to nor associated with the geometric configuration. Forthis purpose a back-reflection of less than 5 % of full screenheight shall be considered to be complete loss of back-reflection.7.1.5 Angle-
28、Beam ExaminationBored or hollow forgingsshall be provided with calibration notches in accordance withPractice A 388/A 388M.7.1.6 A forging that contains a discontinuity that results inan indication exceeding the amplitude of the reference line issubject to rejection.7.1.7 The report of the complete
29、ultrasonic test shall be incompliance with Practice A 388/A 388M.7.2 Magnetic Particle Examination:7.2.1 Each forging shall be examined by a magnetic particlemethod in accordance with Test Method A 275/A 275M afterheat treatment and in the final machined condition, except thatat the purchasers optio
30、n (see 3.1.4) the AC Yoke from TestMethod A 966/A 966M shall be used.7.2.2 Only indications with major dimensions exceeding116in. 1.5 mm shall be considered to be relevant. The followingrelevant indications are unacceptable:7.2.2.1 Any linear indication greater than116 in. 1.5 mm inlength for forgin
31、gs up to and including 1 in. 25 mm inthickness, or greater than18 in. 3 mm in length for forgingsgreater than 1 in. 25 mm but not more than 3 in. 75 mm inthickness, or greater than316 in. 5 mm in length for forgingsgreater than 3 in. 75 mm in thickness.TABLE 1 Chemical Composition %Element Grade 315
32、 Grade 315TaCarbon 0.08-0.12 0.08-0.12Manganese 0.25-0.45 0.25-0.45Phosphorous, max 0.010 0.010Sulfur, max 0.010 0.010Silicon 0.15-0.40 0.15-0.40Nickel, max 0.25 0.25Chromium 2.8-3.2 2.8-3.2Molybdenum 0.65-0.85 0.65-0.85Vanadium 0.20-0.30 0.20-0.30Boron, max 0.0007 0.0007Tungsten 1.35-1.75 1.35-1.75
33、Tantalum . . . 0.07-0.13Aluminum, max 0.015 0.015TABLE 2 Tensile RequirementsProperty Grade 315 and Grade 315TaTensile Strength, ksi MPa 105-135 725-930Yield Strength, ksi MPa min 85 585Elongation in 2 in. 50 mm, % min 16Reduction of Area, % min 50A 1048/A 1048M 0627.2.2.2 Rounded indications with d
34、imensions greater than18 in. 3 mm for thickness dimensions up to and including1 in. 25 mm and316 in. 5 mm for thicknesses over 1 in.25 mm.7.2.2.3 Four or more relevant indications (linear or rounded)in a line and separated by116 in. 1.5 mm or less, edge to edge.7.2.2.4 Ten or more relevant indicatio
35、ns in any6 in.240 cm2 of surface with the major dimension of this areanot to exceed 6 in. 150 mm.8. Certification and Reports8.1 In addition to the certification and reporting require-ments of Specification A 788/A 788M, the manufacturer shallinclude the following:8.2 Product analysis results, and8.
36、3 Sketches or drawings as needed to illustrate the nonde-structive examination reports.9. Keywords9.1 alloy steel forgings; boilers; chromium-molybdenum-tungsten; elevated temperature service; mandatory nondestruc-tive testing; pressure vesselsSUPPLEMENTARY REQUIREMENTSOne or more of the following s
37、upplementary requirements shall apply only when specified by thepurchaser in the order. Additional supplementary requirements are included in SpecificationA 788/A 788M for use by the purchaser. Details of the selected supplementary requirements shall havebeen agreed upon between the manufacturer and
38、 purchaser.S1. Preliminary MachiningS1.1 Forgings shall be rough machined to a drawing pro-vided by, or agreed to by the purchaser prior to heat treatment.S2. Special Tension Test Requirements for Hubbed TubeSheets and FlangesS2.1 For hubbed tube sheets and flanges supplied forASMEBoiler and Pressur
39、e Vessel Code applications, tension andimpact test specimens shall be taken from the hub location asshown in S12 of Specification A 788/A 788M.S2.2 The number of tests shall be as required in Section 6and shall replace those required in Section 6.ASTM International takes no position respecting the v
40、alidity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is s
41、ubject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headq
42、uarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This stan
43、dard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or se
44、rviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 3 Charpy V-Notch Impact Requirements Tested at32F 0C maxProperty Grades 315 and 315TaLateral Expansion, mils mm min 25 0.6 mmMin Average Absorbed Energy, ft-lbf JA35 48Min Single Value, ft-lbf J 25 34ANot more than one specimen from a set of three may be below this value.A 1048/A 1048M 063
