1、Designation: A638/A638M 10Standard Specification forPrecipitation Hardening Iron Base Superalloy Bars,Forgings, and Forging Stock for High-Temperature Service1This standard is issued under the fixed designation A638/A638M; the number immediately following the designation indicates the yearof origina
2、l adoption or, in the case 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 hot-finished or cold-finishedprecipitat
3、ion hardening iron base superalloy bars, forgings, andforging stock for high-temperature service. The mechanicalproperties of these alloys are developed by suitable solutiontreating and precipitation hardening treatments.1.2 Two grades of iron base alloy are covered. Selection willdepend upon design
4、, service conditions, mechanical properties,and elevated temperature characteristics.1.3 The values stated in either inch-pound units or SI(metric) units are to be regarded separately as standards; withinthe text and tables, the SI units are shown in brackets. Thevalues stated in each system are not
5、 exact equivalents; there-fore, each system must be used independent of the other.Combining values from the two systems may result in noncon-formance with the specification.1.4 Unless the order specifies an “M” designation, thematerial shall be furnished to inch-pound units.2. Referenced Documents2.
6、1 ASTM Standards:3A484/A484M Specification for General Requirements forStainless Steel Bars, Billets, and ForgingsA751 Test Methods, Practices, and Terminology for Chemi-cal Analysis of Steel ProductsE30 Test Methods for Chemical Analysis of Steel, CastIron, Open-Hearth Iron, and Wrought Iron4E527 P
7、ractice for Numbering Metals and Alloys in theUnified Numbering System (UNS)3. Ordering Information3.1 It is the responsibility of the purchaser to specify allrequirements that are necessary for material ordered under thisspecification. Such requirements may include, but are notlimited to, the follo
8、wing:3.1.1 Quantity (weight or number of pieces),3.1.2 Name of material (precipitation hardening iron basesuperalloy),3.1.3 Form (bars, forgings, and forging stock),3.1.4 Dimensions (in the case of rough or finished forgingsthe order shall be accompanied by a print or drawing orotherwise adequately
9、described as to the shape and dimension),3.1.5 Grade designation (Table 1),3.1.6 Condition (Section 5),3.1.7 Finish (Section 3),3.1.8 Mechanical requirements (Section 8),3.1.9 ASTM designation, and3.1.10 Special requirements.4. General Requirements4.1 In addition to the requirements of this specific
10、ation, allrequirements of the current edition of Specification A484/A484M shall apply. Failure to comply with the generalrequirements of Specification A484/A484M constitutes non-conformance with this specification.5. Condition5.1 The product forms covered in this specification may befurnished in one
11、 of the following conditions:5.1.1 Hot-finished,5.1.2 Solution treated (Grade 660 onlyType 1 or Type 2solution treatment as specified),5.1.3 Solution and precipitation treated (Grade 660 onlyType 1 or Type 2 solution treatment as specified), or5.1.4 Other as specified.1This specification is under th
12、e jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.17 on Flat-Rolled and Wrought Stainless Steel.Current edition approved April 1, 2010. Published April 2010. Originallyapproved in 1970. Last previous edition approved
13、in 2004 as A638/A638M 00(2004). DOI: 10.1520/A0638_A0638M-10.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-638 in Section II of that Code.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. F
14、or Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Interna
15、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Heat Treatment6.1 Samples cut from bars, forgings, or a sample forgedfrom the forging stock shall conform to the mechanicalproperties of Table 1 and Table 2 when heat treated asprescribed in Table 3.6.2 Wh
16、en a sample cut from the forging stock and heattreated as prescribed in Table 2 conforms to the properties inTables 3 and 4, it shall be accepted as equivalent to a forgedcoupon.7. Chemical Composition7.1 The steel shall conform to the requirements for chemicalcomposition specified in Table 4.7.2 Me
17、thods and practices relating to chemical analysisrequired by this specification shall be in accordance with TestMethods, Practices, and Terminology A751, except that forremelt material, product analysis tolerances may be used todetermine conformance to this specification.7.3 For referee purposes, Te
18、st Methods E30 shall be used.7.4 Methods and practices relating to chemical analysisrequired by this specification shall be in accordance with TestMethods, Practices, and Definitions A751, except that forremelt material, product analysis tolerances may be used todetermine conformance to this specifi
19、cation.8. Mechanical Properties8.1 The material shall conform to the mechanical propertyrequirements specified in Table 1 after heat treatment asdescribed in Table 3.8.2 The material shall meet the requirements as to stress-rupture properties specified in Table 2 at the test temperatureindicated aft
20、er heat treatment as described in Table 3.8.3 When specified in the ordering information (3.1.8),material may be ordered without stress-rupture testing. Mate-rial not stress-rupture tested shall be permanently stamped NR(See Section 10).9. Metallurgical Properties9.1 When specified, the grain size s
21、hall be 1 or finer.10. Product Marking10.1 Unless otherwise specified on the purchase order, eachbundle shall be properly tagged with metal tags showing thepurchase order number, heat number, name of alloy (or grade),“NR” when material has not been stress-rupture tested,specification number, and siz
22、e.10.1.1 Bars 1 in. 25 mm and over in diameter, or 1 in. 25mm and over in thickness between parallel sides, shall beTABLE 1 Mechanical Property RequirementsGrade 660 Grade 662 (bars) Grade 662 (forgings)AHeat treatmentBsolution + precipitationhardensolution + precipitationhardensolution + precipitat
23、ionhardenTensile strength, min:psi 130 000 130 000 125 000MPa 895 895 860Yield strength (0.2 % offset), min:psi 85 000 85 000 80 000MPa 585 585 550Elongation in 4D min, % 15 15 15Reduction of area min, % 18 18 18Brinell hardness 248 min 248 min 248 minAThe elongation of tensile specimens machined ta
24、ngentially from near the center of large disk forgings over 50 in.2320 cm2 in cross section may be as low as 10 %.The reduction of area may be as low as 12 %.BRefer to Table 3 of heat treatment.TABLE 2 Stress-Rupture RequirementsGrade Heat TreatmentATest Temperature Applied Stress During Stress-Rupt
25、ure TestingMinimumHoursBMinimumElongation, %F C psi MPa660 solution + precipitation harden 1200 650 65 000 450 23 3662 solution + precipitation harden 1200 650 60 000 415 15 3ARefer to Table 3 for details of heat treatment.BTest specimens meeting minimum requirements may be overloaded to produce rup
26、ture in a reasonable and practical time period.TABLE 3 Heat TreatmentGrade Solution Treatment Precipitation HardeningTreatmentA660 Type 11650 6 25F 900 6 15C, 1300 to 1400F 705 tohold 2 hr, oil or water 760C, hold 16 h, air cool orquench furnace cool660 Type 21800 6 25F 980 6 15C, 1300 to 1400F 705
27、tohold 1 h, oil or water 760C, hold 16 h, air cool orquench furnace cool662 1750 to 1900F 955 to 1250 to 1400F 675 to1040C hold 1 h, min, oil or 760C, hold 5 h, min, slowwater quench cooling in 5 h, min to 12006 15F 650 6 10C, hold20 h, min, air cool or furnacecoolATimes refer to the minimum time ma
28、terial is required to be at temperature.A638/A638M 102stamped with the heat number, and if not stress-rupture tested,with the letters “NR” within approximately 2 in. 50 mm ofone end. Smaller sizes shall be boxed or bundled and identifiedwith metal tags as described in 10.1.10.1.2 Forgings shall be i
29、dentified as agreed upon betweenthe seller and the purchaser.11. Keywords11.1 precipitation hardening superalloy steel; superalloysteel bars; superalloy steel billets; superalloy steel forgings;temperature service applicationshighSUMMARY OF CHANGESCommittee A01 has identified the location of selecte
30、d changes to this standard since the last issue(A638/A638M 00 (2004) that may impact the use of this standard. (Approved April 1, 2010.)(1) Revised column heading in Table 2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mention
31、edin 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 subject to revision at any time by the responsible technical committee and
32、 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 Headquarters. Your comments will receive careful consideration at a meeting of
33、 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
34、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 serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permis
35、sion rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 4 Chemical RequirementsGrade 660 (UNS S 66286)AGrade 662 (UNS S 66220)ALadle AnalysisRange, %Check Analysis Overor UnderLadle AnalysisRange, %Check Analysis Overor UnderCarbon 0.08 max 0.0
36、1 over 0.08 max 0.01 overManganese 2.00 max 0.04 over 1.50 max 0.04Silicon 1.00 max 0.05 over 1.00 max 0.05Phosphorus 0.040 max 0.005 over 0.040 max 0.005 overSulfur 0.030 max 0.005 over 0.030 max 0.005 overChromium 13.5016.00 0.20 12.0015.00 0.15Nickel 24.0027.00 0.20 24.0028.00 0.20Molybdenum 1.00
37、1.50 0.05 2.503.50 0.10Titanium 1.902.35 0.05 1.552.00 0.05Copper . . 0.50 max 0.03 overAluminum 0.35 max 0.05 over 0.35 max 0.05 overVanadium 0.100.50 0.03 . .Boron 0.00100.010 0.0004 under 0.00100.010 0.0004 under0.001 over 0.001 overANew designation established in accordance with Practice E527 and SAE J 1086.A638/A638M 103
