1、Designation: A 739 90a (Reapproved 2006)Standard Specification forSteel Bars, Alloy, Hot-Wrought, for Elevated Temperature orPressure-Containing Parts, or Both1This standard is issued under the fixed designation A 739; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.
3、1. Scope1.1 This specification2covers hot-wrought, ferritic alloysteel bars for elevated temperature or pressure-containing partssuitable for fusion welding or both.1.2 The bars are furnished in the following grades:Grade B 11: 1.25 % chromium, 0.55 % molybdenumGrade B 22: 2.25 % chromium, 1.00 % mo
4、lybdenum1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2. Referenced Documents2.1 ASTM Standards:3A 29/A 29M Specification for Steel
5、 Bars, Carbon andAlloy,Hot-Wrought, General Requirements forA 370 Test Methods and Definitions for Mechanical Testingof Steel Products3. Ordering Information3.1 Orders for material under this specification shouldinclude the following information:3.1.1 Quantity (weight or number of pieces),3.1.2 Name
6、 of material (ferritic alloy steel bars),3.1.3 Condition (hot wrought, normalized and tempered,machine straightened and descaled),3.1.4 Dimensions (cross-sectional shape, size, and length),3.1.5 ASTM designation and date of issue,3.1.6 Grade (Table 1),3.1.7 Additions to the specification, and3.1.8 E
7、nd use.NOTE 1A typical description is as follows: 10 000 lb, Ferritic AlloySteel Bars, Hot Wrought Normalized and Tempered, and Descaled,1.000-in. diameter by 10 ft, ASTM A 739 dated_, Grade B 11, SpecialStraightened, Special Machined Fittings.4. Materials and Manufacture4.1 Melting PracticeThe stee
8、l shall be made by one ormore of the following primary processes: open-hearth, basic-oxygen, or electric-furnace. The primary melting may incor-porate separate degassing or refining and may be followed bysecondary melting using electroslag remelting or vacuum arcremelting. Where secondary melting is
9、 employed, the heatshall be defined as all of the ingots remelted from a singleprimary heat.4.2 ConditionUnless otherwise specified, bars shall behot wrought, heat treated, and descaled.4.3 Heat Treatment:4.3.1 The bars shall be normalized and tempered.4.3.2 Austenitizing temperature shall be within
10、 the rangefrom 1700 to 1800F (927 to 982C).4.3.3 Cooling from the austenitizing temperature may beaccomplished by cooling in still air or moving air, at theproducers option. When permitted by the purchaser, coolingfrom the austenitizing temperature may be accelerated by sprayor liquid quenching.4.3.
11、4 The minimum tempering temperature shall be 1200F(649C) for Grade B 11 and 1250F (677C) for Grade B 22.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.15 on Bars.Current edition appro
12、ved March 1, 2006. Published March 2006. Originallyapproved in 1976. Last previous edition approved in 2000 as A 739 90a (2000).2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-739 in Section II of that code.3For referenced ASTM standards, visit the ASTM website,
13、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.TABLE 1 Chemical RequirementsElement Composition, %Grade B 11 Grade B 22Carbon, max 0.050.20 0.050.15Manganese 0.400.
14、65 0.300.60Phosphorus, max 0.035 0.035Sulfur, max 0.040 0.040Silicon 0.500.80 0.50 maxChromium 1.001.50 2.002.50Molybdenum 0.450.65 0.901.101Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Chemical Composition5.1 The heat analysis
15、shall conform to the limits for chemi-cal composition specified in Table 1 for the grade ordered.6. Mechanical Properties6.1 Tensile RequirementsThe bars as represented by thetest specimens shall conform to the tensile requirementsspecified in Table 2.6.2 SpecimensTension test specimens shall be tak
16、en lon-gitudinally and machined from the locations specified in TestMethods and Definitions A 370.6.3 Number of Tests:6.3.1 Two tension tests shall be made to represent bars ofthe same size from each heat in each heat treatment charge. Forcontinuous heat-treated material, not fewer than two tensiont
17、ests shall represent a lot selected on the basis of one tensiontest from each 10 000 lb (4500 kg).6.3.2 When heat treated without interruption in continuousfurnaces, the material in a lot shall be from the same heat, sameprior condition, same size, and subjected to the same heattreatments.6.4 Test M
18、ethodsTension tests shall be made in accor-dance with Test Methods and Definitions A 370. The yieldstrength shall be determined by the 0.2 % offset method.7. Workmanship, Finish, and Appearance7.1 WorkmanshipThe bars shall be free of pipe, cracks,and flakes. Within the limits of good manufacturing a
19、ndinspection practices the bars shall be free of injurious seams,laps, segregation, or other imperfections which, due to theirnature, degree or extent, will interfere with the use of thematerial in machining or fabrication.7.2 DescalingUnless otherwise specified, the bars shallbe descaled.8. General
20、 Requirements8.1 Material furnished under this specification shall con-form to the applicable requirements of the current edition ofSpecification A 29/A 29M.9. Certification and Test Reports9.1 A manufacturers certification that the material wasmanufactured and tested in accordance with this specifi
21、cationtogether with a report of the analysis and tension test resultsshall be furnished at the time of shipment. The report shallinclude the name of the manufacturer, ASTM designationnumber and year date and revision letter, if any, grade, heatnumber, and size.10. Product Marking10.1 The bars shall
22、be marked in accordance with Specifi-cation A 29/A 29M except as modified or supplemented by10.2 through 10.4 of this specification.10.2 When specified by the purchaser, the heat number shallbe permanently stamped on one end of each bar 2.50 in. andlarger in nominal diameter (or equivalent cross-sec
23、tional area).10.3 The bars shall neither be hot nor cold stamped on thesides unless approved by the purchaser on the purchase order.10.4 Each lift, regardless of size, shall be tagged with theinformation required by Specification A 29/A 29M.11. Keywords11.1 alloy steel bars; high-temperature applica
24、tions; hot-wrought steel bars; pressure-containing parts; steel bars; tem-perature service applicationhighASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised tha
25、t determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reappro
26、ved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you fe
27、el 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual rep
28、rints (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 serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Tensile RequirementsGrade B 11 Grade B 22Tensile strength, ksi (MPa) 70.095.0 (483655) 75.095.0 (517655)Yield strength, min, ksi (MPa) 45.0 (310) 45.0 (310)Elongation in 2 in. or 50 mm,min, %18 18Reduction of area, min, % 45 45A 739 90a (2006)2
