1、Designation: A668/A668M 131A668/A668M 14 American Association StateHighway and Transportation Officials StandardAASHTO No.: M 102Standard Specification forSteel Forgings, Carbon and Alloy, for General IndustrialUse1This standard is issued under the fixed designation A668/A668M; the number immediatel
2、y following the designation indicates the yearof original 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.This standard has been
3、 approved for use by agencies of the U.S. Department of Defense.1 NOTESections 6.1 and 7.1.4.3 were editorially corrected in August 2013.1. Scope*1.1 This specification covers untreated and heat-treated carbon and alloy steel forgings for general industrial use. Other ASTMspecifications for forgings
4、 are available for specific applications such as pressure vessels, railroad use, turbine generators, gearing,and others involving special temperature requirements.1.2 Hot-rolled or cold finished bars are not within the scope of this specification.1.3 Six classes of carbon steel and seven classes of
5、alloy steel forgings are listed (see Section 7), which indicates their requiredheat treatments, as well as mechanical properties.1.4 Provision, with the suffix H for certification and marking, for the supply of forgings after hardness testing only.1.5 Supplementary requirements, including those in S
6、pecification A788/A788M, of an optional nature are provided. These shallapply only when specified by the purchaser.1.6 Appendix X1 lists the current classes corresponding to the various classes of Specifications A235, A237, and A243, whichhave been superseded by this specification.1.7 The values sta
7、ted in either SI units or inch-pound units are to be regarded separately as standard; within the text and tables,the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shallbe used independently of the other. Combining values from th
8、e two systems may result in nonconformance with the standard.1.8 Unless the order specifies the applicable “M“ specification, the forgings shall be furnished to the inch-pound units.2. Referenced Documents2.1 ASTM Standards:2A275/A275M Practice for Magnetic Particle Examination of Steel ForgingsA370
9、 Test Methods and Definitions for Mechanical Testing of Steel ProductsA388/A388M Practice for Ultrasonic Examination of Steel ForgingsA788/A788M Specification for Steel Forgings, General RequirementsE290 Test Methods for Bend Testing of Material for DuctilityE381E340 Method of Macroetch Testing Stee
10、l Bars, Billets, Blooms, and ForgingsTest Method for Macroetching Metals andAlloys3. Terminology3.1 The terminology section of Specification A788/A788M is applicable to this specification.3.2 Definitions of Terms Specific to This Standard:1 This specification is under the jurisdiction ofASTM Committ
11、ee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee A01.06on Steel Forgings and Billets.Current edition approved June 1, 2013Oct. 1, 2014. Published June 2013October 2014. Originally approved in 1972. Last previous edition approved in 20092013 asA668/A
12、668M 04(2009). 13. DOI: 10.1520/A0668_A0668M-13E01.10.1520/A0668_A0668M-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the
13、 ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users con
14、sult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
15、, PA 19428-2959. United States13.2.1 classa description of steel forgings based on heat treatment, mechanical properties and composition.3.2.2 controlling cross section thickness (TC)the diameter of the largest theoretical sphere which can be inscribed within thevolume of the forging.3.2.3 TPdesigna
16、tes prolongations which have a size other than the controlling cross section thickness (TC).4. Ordering Information and General Requirements4.1 Material supplied to this specification shall conform to the requirements of Specification A788/A788M which outlinesadditional ordering information, manufac
17、turing requirements, testing and retesting methods and procedures, marking, certification,product analysis variations and additional supplementary requirements.4.1.1 If the requirements of this specification are in conflict with the requirements of Specification A788/A788M, therequirements of this s
18、pecification shall prevail.4.2 When this specification is to be applied to an inquiry, contract, or order, the purchaser should furnish the followinginformation:4.2.1 The ordering information required by Specification A788/A788M,4.2.2 The class of forging desired as listed in Table 1,4.2.3 Location(
19、s) of areas of significant loading if test specimens are to be located in accordance with 7.1.4.5,4.2.4 The options which may be selected as found in 5.3.2, 6.1, and 7.3, and4.2.5 Any applicable supplementary requirements.5. Materials and Manufacture5.1 DiscardSufficient discard shall be made from e
20、ach ingot to secure freedom from piping and undue segregation.5.2 Forging Process:5.2.1 The forging shall be brought as close as practical to finished shape and size by hot mechanical work.5.2.2 Supplementary requirements S2, S14, and S15 may be specified by the purchaser to satisfy concerns about t
21、he utility ofthe proposed forging.5.3 Heat Treatment:5.3.1 All forgings, other than Class A, shall be heat treated. See Section 7.5.3.2 Where options exist within a class, the choice of heat treatment shall be left to the discretion of the manufacturer, unlessthe purchaser specifies one of the avail
22、able options.6. Chemical Composition6.1 The steel shall conform to the requirements prescribed in Table 1.6.2 The choice of chemical composition is left to the discretion of the manufacturer, unless otherwise specified by the purchaser.See Appendix X2.6.3 Heat Analysis:6.3.1 An analysis of each heat
23、 shall be made by the manufacturer.6.4 Product AnalysisAn analysis may be made by the purchaser according to the requirements of Specification A788/A788M.If a standard grade has been used to manufacture the forging the permissible variations in composition of SpecificationA788/A788M shall apply. If
24、a non-standard grade of steel has been used, and composition limits have not been supplied, theproduct analysis can be used only to confirm the type of steel supplied.7. Mechanical Properties7.1 Tensile Requirements:7.1.1 The material shall conform to the tensile properties prescribed in Table 2. Se
25、e Test Methods and Definitions A370.7.1.2 All ForgingsThe dimensions of the controlling cross section thickness (TC) of the forging at time of heat treatmentdetermine the mechanical properties to be met within each class (see Table 2) except as noted in 7.1.4.2.TABLE 1 Chemical RequirementsElements
26、Composition, max, %Classes A to Fand AH to FHClasses G to Nand GH to NHManganese 1.35 .Phosphorus 0.050 0.040Sulfur 0.025 0.025A668/A668M 1427.1.3 Number of TestsUnless the purchaser specifies that forgings shall be furnished in accordance with the requirements of7.3, the number of tension tests per
27、formed shall be as follows:7.1.3.1 For all classes of heat-treated forgings with as-heat treated weights (excluding test prolongations) less than 5000 lb2250 kg each, one test shall be made from each size classification represented in each heat in each annealing or normalizingcharge, or from each si
28、ze classification in each heat in each normalizing or quenching charge represented in each tempering charge.For untreated forgings (Class A) weighing less than 5000 lb 2250 kg each, one test from each heat shall be made.7.1.3.2 On all classes, for forgings with as-heat treated weights (excluding tes
29、t prolongations) of 5000 lb 2250 kg or more,at least one test from each forging shall be made.TABLE 2 Tensile RequirementsA,BClassControlling CrossSection (TC),in. mmTensile Strength, minYield Point, YieldStrength 0.2 %Offset, minElonga-tion in 2in. or50 mm,min, %Reduc-tion ofArea,min, %BrinellHardn
30、ess(HBW)Over Not Over psi MPa psi MPaCarbon SteelA (AH) (Untreated) . 20 500 47 000 325 . . . . 183 maxB (BH) (Annealed, or normalized, ornormalized and tempered). 20 500 60 000 415 30 000 205 24 36 120174C (CH) (Annealed, or normalized, or . 12 300 66 000 455 33 000 230 23 36 137183normalized and t
31、empered) 12 300 20 500 66 000 455 33 000 230 22 34 137183D (DH) (Normalized, annealed, or normalized . 8 200 75 000 515 37 500 260 24 40 149207and tempered) 8 200 12 300 75 000 515 37 500 260 22 35 14920712 300 20 500 75 000 515 37 500 260 20 32 14920720 500 75 000 515 37 500 260 19 30 149207E (EH)
32、(Normalized and tempered or . 8 200 85 000 585 44 000 305 25 40 174217double-normalized and tempered) 8 200 12 300 83 000 570 43 000 295 23 37 17421712 300 20 500 83 000 570 43 000 295 22 35 174217F (FH) (Quenched and tempered, or . 4 100 90 000 620 55 000 380 20 39 187235normalized, quenched and te
33、mpered) 4 100 7 175 85 000 585 50 000 345 20 39 1742177 175 10 254 85 000 585 50 000 345 19 37 17421710 250 20 500 82 000 565 48 000 330 19 36 174217Alloy SteelG (GH) (Annealed, or normalized, or . 12 300 80 000 550 50 000 345 24 40 163207normalized and tempered) 12 300 20 500 80 000 550 50 000 345
34、22 38 163207H (HH) (Normalized and tempered) . 7 175 90 000 620 60 000 415 22 44 1872357 175 10 250 90 000 620 58 000 400 21 42 18723510 250 20 500 90 000 620 58 000 400 18 40 187235J (JH) (Normalized and tempered, or . 7 175 95 000 655 70 000 485 20 50 197255normalized, quenched, and tempered) 7 17
35、5 10 250 90 000 620 65 000 450 20 50 18723510 250 20 500 90 000 620 65 000 450 18 48 207255K (KH) (Normalized, quenched, and tempered) . 7 178 105 000 725 80 000 550 20 50 2122697 175 10 250 100 000 690 75 000 515 19 50 20726910 250 20 500 100 000 690 75 000 515 18 48 207269L (LH) (Normalized, quenc
36、hed, and tempered) . 4 100 125 000 860 105 000 725 16 50 2553214 100 7 175 115 000 795 95 000 655 16 45 2353027 175 10 250 110 000 760 85 000 585 16 45 22329310 250 20 500 110 000 760 85 000 585 14 40 223293M (MH) (Normalized, quenched, . 4 100 145 000 1000 120 000 825 15 45 293352and tempered) 4 10
37、0 7 175 140 000 965 115 000 790 14 40 2853417 178 10 254 135 000 930 110 000 758 13 40 26933110 250 20 500 135 000 930 110 000 758 12 38 269341N (NH) (Normalized, quenched, and tempered) . 4 100 170 000 1175 140 000 965 13 40 3314014 100 7 175 165 000 1140 135 000 930 12 35 3314017 175 10 250 160 00
38、0 1100 130 000 900 11 35 32138810 250 20 500 160 000 1100 130 000 900 11 35 321402A Forgingswithcontrollingcrosssectionthickness(TC)inexcessof20in.508mmforallclassesotherthanclassDmaybecertifiedtoSpecificationA668/A668Mprovidedthey meet the requirements for controlling cross sections of 20 in. 508 m
39、m listed in Table 2. Alternatively, the manufacturer and purchaser may agree upon the requiredmechanical property values as described in Supplement S9.1.B Requirements presented in Table 2 are to be met at the test locations given in 7.1.4. Tests from other locations may not exhibit the property val
40、ues shown in Table 2.A668/A668M 1437.1.3.3 On all classes, for forgings with as-heat treated weights (excluding test prolongations) of 7000 lb 3200 kg or more,two tests will be taken: on ring and disk forgings 180 apart; on shafts and long hollow cylinders (over 80 in. 2.0 m in lengthexcluding test
41、material), one from each end and offset 180. Shafts and cylinder forgings 80 in. 2.0 m or less in length (excludingtest material) may have both tests located at one end 180 apart.7.1.3.4 When forgings are made in multiple as a single forging, that is, forged as one piece and divided after heat treat
42、ment,the multiple forging shall be considered as one forging, and the number of tests required shall be as designated in 7.1.3.1, 7.1.3.2,and 7.1.3.3.7.1.4 Prolongations:7.1.4.1 A sufficient number of the forgings shall have prolongations for extracting specimens for testing. Examples of testlocatio
43、ns for various forging configurations are shown in Figs. 1 and 2.FIG. 1 Examples of Locations of Test Specimens for Various Types of Forgings (see Note 1).A668/A668M 144FIG. 2 Examples of Locations of Test Specimens for Various Types of Forgings (see Note 1).A668/A668M 145NOTE 1Figures provided demo
44、nstrate the concept of controlling cross section thickness (TC) but do not encompass all possible test prolongationconfigurations which meet the requirements of Section 7.7.1.4.2 For all forgings of non-uniform cross section in classes A, B, C, D, E, G and H: The prolongation(s) may be extensionsof
45、sections other than the controlling cross section thickness (TC), that is TP TC. In this case, the dimension of TP shall determinethe mechanical properties to be met within each class. When TP TC, TP shall not have more reduction than the smallest crosssection to be qualified.(1) For annealed, norma
46、lized, or normalized and tempered forgings in classes A, B, C, D, E, G and H the center of the gagelength axis of tension test specimens shall be 14 the controlling cross section thickness (TC) from one surface except as noted in7.1.4.2 (2).(2) If the prolongation thickness (TP) is less than the con
47、trolling cross section thickness (TC) the center of the gage length axisof the tension test shall be of the prolongation thickness (TP) from one surface.7.1.4.3 For quenched forgings in Classes F, J, K, L, M, and N, the center of the gage length axis of the tension test specimenshall be at a minimum
48、 14 (TC) from one quenched surface and 312 in. 90 mm from all other quenched surfaces.the nearest secondsurface.7.1.4.4 In place of prolongations, the manufacturer may: (1) elect to submit a representative forging(s) to represent each test lot;in this event, the representative forging must be made f
49、rom the same heat of steel, must not receive more reduction than the forgingit represents, must receive the same type of hot working it represents, be of the same controlling cross section thickness (TC), andhave been heat treated in the same furnace charge as the forging(s) it represents; or (2) obtain the test specimen from the trepannedmaterial of transverse or radial hol
