1、Designation: A 668/A 668M 04American Association StateHighway and Transportation Officials StandardAASHTO No.: M 102Standard Specification forSteel Forgings, Carbon and Alloy, for General IndustrialUse1This standard is issued under the fixed designationA 668/A 668M; the number immediately following
2、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 (e) indicates an editorial change since the last revision or reapproval.This standard has been approved f
3、or use by agencies of the Department of Defense.1. Scope*1.1 This specification covers untreated and heat-treatedcarbon and alloy steel forgings for general industrial use. OtherASTM specifications for forgings are available for specificapplications such as pressure vessels, railroad use, turbinegen
4、erators, gearing, and others involving special temperaturerequirements.1.2 Hot-rolled or cold finished bars are not within the scopeof this specification.1.3 Six classes of carbon steel and seven classes of alloysteel forgings are listed (see Section 7) , which indicates theirrequired heat treatment
5、s, as well as mechanical properties.1.4 Provision, with the suffix H for certification and mark-ing, for the supply of forgings after hardness testing only.1.5 Supplementary requirements, including those in Speci-fication A 788, of an optional nature are provided. These shallapply only when specifie
6、d by the purchaser.1.6 Appendix X1 lists the current classes corresponding tothe various classes of Specifications A 235, A 237, and A 243,which have been superseded by this specification.1.7 The values stated in either inch-pound units or SI unitsare to be regarded separately as the standard; withi
7、n the textand tables, the SI units are shown in brackets. The values statedin each system are not exactly equivalent; therefore; eachsystem must be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the specification.1.8 Unless the order specifies
8、the applicable 9M9 specifica-tion, the forgings shall be furnished to the inch-pound units2. Referenced Documents2.1 ASTM Standards:2A 275/A 275M Test Method for Magnetic Particle Exami-nation of Steel ForgingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 388/A 388M Pra
9、ctice for Ultrasonic Examination ofHeavy Steel ForgingsA 788 Specification for Steel Forgings, General Require-mentsE 381 Method of Macroetch Testing Steel Bars, Billets,Blooms, and Forgings3. Terminology3.1 The terminology section of Specification A 788 isapplicable to this specification.3.2 Defini
10、tions of Terms Specific to This Standard:3.2.1 hollow cylindrical forginga forging whose length,as measured on its longitudinal axis is more than its diameter,shall be considered as a hollow cylinder within the scope ofthis specification if it has been lengthened by extrusion orforged in a manner si
11、milar to that of a ring, namely, expandedin diameter on a mandrel.3.2.2 ring-shaped or disk-shaped forginga forging whoselength, as measured on its longitudinal axis, is less than itsdiameter or main transverse dimension is considered a ring ordisk within the meaning of this specification.4. Orderin
12、g Information and General Requirements4.1 Material supplied to this specification shall conform tothe requirements of Specification A 788 which outlines addi-tional ordering information, manufacturing requirements, test-ing and retesting methods and procedures, marking, certifica-tion, product analy
13、sis variations and additional supplementaryrequirements.4.1.1 If the requirements of this specification are in conflictwith the requirements of Specification A 788, the requirementsof this specification shall prevail.4.2 When this specification is to be applied to an inquiry,contract, or order, the
14、purchaser should furnish the followinginformation:4.2.1 The ordering information required by Specification A788.1This 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 a
15、nd Billets.Current edition approved March 1, 2004. Published April 2004. Originallyapproved in 1972. Last previous edition approved in 2003 as A 668 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSta
16、ndards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.2 The class of forging d
17、esired as listed in Section Table1,4.2.3 Location(s) of areas of significant loading if testspecimens are to be located in accordance with 7.1.4.5.4.2.4 The options which may be selected as found in 5.4.2,7.6.3, and 7.7, and4.2.5 Any applicable supplementary requirements.5. Materials and Manufacture
18、5.1 DiscardSufficient discard shall be made from eachingot to secure freedom from piping and undue segregation.5.2 Forging Process5.2.1 The forging shall be brought as close as practical tofinished shape and size by hot mechanical work.5.2.2 Supplementary requirements S2, S14, and S15 may bespecifie
19、d by the purchaser to satisfy concerns about the utilityof the 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 heattreatment shall be left to the discretion of the manufacturer,unl
20、ess the purchaser specifies one of the available options.6. Chemical Composition6.1 The steel shall conform to the requirements for chemicalcomposition prescribed in Table 1.6.2 The choice of chemical composition is left to thediscretion of the manufacturer, unless otherwise specified bythe purchase
21、r. See Appendix X2.6.3 Heat Analysis:6.3.1 An analysis of each heat shall be made by themanufacturer.6.4 Product AnalysisAn analysis may be made by thepurchaser according to the requirements of SpecificationA 788. If a standard grade has been used to manufacture theforging the permissible variations
22、 in composition of Specifi-cation A 788 shall apply. If a non-standard grade of steel hasbeen used, and composition limits have not been supplied, theproduct analysis can be used only to confirm the type of steelsupplied.7. Mechanical Properties7.1 Tensile Requirements:7.1.1 The material shall confo
23、rm to the tensile propertiesprescribed in Table 2.7.1.2 Size ClassificationThe dimensions of the forging attime of heat treatment determine the size classification (seeTable 2):7.1.2.1 Solid ForgingsEither the as forged or rough ma-chined diameter or thickness of solid forgings, disregardinglarge en
24、ds, collars, flanges, and journals, at time of heattreatment shall determine the size classification.7.1.2.2 Ring or Hollow Cylinder Forging The size clas-sification shall be determined by its wall thickness or width,whichever is the smaller dimension of either the as forged orrough machined forging
25、 at time of heat treatment.7.1.3 Number of TestsUnless the purchaser specifies thatforgings shall be furnished in accordance with the requirementsof 7.3, the number of tension tests performed shall be asfollows:7.1.3.1 For all classes of heat-treated forgings with roughmachined weights less than 500
26、0 lb 2250 kg each, one testshall be made from each size classification represented in eachheat in each annealing or normalizing charge, or from each sizeclassification in each heat in each normalizing or quenchingcharge represented in each tempering charge. For untreatedforgings (Class A) weighing l
27、ess than 5000 lb 2250 kg each,one test from each heat shall be made.7.1.3.2 On all classes, for forgings with rough machinedweights of 5000 lb 2250 kg or more, at least one test fromeach forging shall be made.7.1.3.3 On all classes, for forgings with rough machinedweights of 7000 lb 3200 kg or more,
28、 two tests will be taken:on ring and disk forgings 180 apart; on shafts and longhollow cylinders (over 80 in. 2.0 m in length excluding testmaterial), one from each end and offset 180 . Shafts andcylinder forgings 80 in. 2.0 m or less in length (excluding testmaterial) may have both tests located at
29、 one end 180 apart.7.1.3.4 When forgings are made in multiple as a singleforging, that is, forged as one piece and divided after heattreatment, the multiple forging shall be considered as oneforging, and the number of tests required shall be as designatedin 7.1.3.1, 7.1.3.2, and 7.1.3.3.7.1.4 Prolon
30、gations:7.1.4.1 A sufficient number of the forgings shall haveprolongations for extracting specimens for testing. Locationsof test specimens for various types of forgings shall be asshown in Fig. 1.7.1.4.2 The nominal or principal outside rough machinediameter or thickness of the forgings, disregard
31、ing large ends,collars, flanges, and journals shall determine the size of theprolongations for test specimens; however, the prolongationson annealed, normalized, or normalized and tempered shaftsmay be extensions of the small diameter end of the shaft, asshown in Fig. 1.7.1.4.3 For quenched forgings
32、 in Classes F, J, K, L, M, andN, the prolongations shall be sufficiently long so that the centerof the gage length (for longitudinal specimens) or axis (fortangential specimens) of the tension test specimen shall be atthe following locations:(1) On solid round forgings, bars, or billets (see Fig. 1
33、(a),at midradius and from the end, 312 in. 90 mm or12 thediameter, whichever is less.(2) On solid rectangular forgings, bars, or billets, at14 thethickness and width and from the end, 312 in. 90 mm or12the thickness, whichever is less.TABLE 1 Chemical RequirementsElements Composition, max, %Classes
34、A to Fand AH to FHClasses G to Nand GH to NHManganese 1.35 .Phosphorus 0.050 0.040Sulfur 0.050 0.040A 668/A 668M 042(3) On disk forgings (see Fig. 1(c) (with prolongation onOD), at midthickness and from the OD 312 in. 90 mm or12the thickness, whichever is less.(4) On disk forgings (see Fig. 1(c) (wi
35、th prolongation onthe width or thickness) 312 in. 90 mm or12 the thickness,whichever is less, from any heat treated surface.(5) On ring forgings (see Fig. 1(d) (with prolongation onwidth), at midwall and from the ring face 312 in. 90 mm or12 the wall thickness, whichever is less.(6) On ring forgings
36、 (see Fig. 1(d) (with prolongation onthe OD), at midwidth and from the OD 312 in. 90 mm or12the width, whichever is less.7.1.4.4 In place of prolongs, the manufacturer may: (1) electto submit an extra forging(s) to represent each test lot; in thisevent, the representative forging must be made from t
37、he sameheat of steel, have received the same reduction and type of hotworking, be of the same nominal thickness, and have been heattreated in the same furnace charge as the forging(s) it repre-sents; or (2) obtain the test specimen from the trepannedmaterial of transverse or radial holes, provided d
38、epth is equalto or greater than the minimum depth required by 7.1.4.3.7.1.4.5 With prior purchaser approval, test specimens maybe taken at a depth (t) corresponding to the distance from thearea of significant stress to the nearest heat treated surface andTABLE 2 Tensile RequirementsClassSize, in. mm
39、 Tensile Strength, minYield Point, YieldStrength 0.2 %Offset, minElonga-tionin2in. or50 mm,min, %Reduc-tion ofArea,min, %BrinellHardnessOver 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 6
40、0 000 415 30 000 205 24 36 120174C (CH) (Annealed, or normalized, or . 12 300 66 000 455 33 000 230 23 36 137183normalized and tempered) 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
41、 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) (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 57
42、0 43 000 295 22 35 174217F (FH) (Quenched and tempered, or . 4 100 90 000 620 55 000 380 20 39 187235normalized, quenched and tempered) 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) (Anne
43、aled, 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 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
44、 40 187235J (JH) (Normalized and tempered, or . 7 175 95 000 655 70 000 485 20 50 197255normalized, quenched, and tempered) 7 175 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
45、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, quenched, 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
46、110 000 760 85 000 585 14 40 223293M (MH) (Normalized, quenched, . 4 100 145 000 1000 120 000 825 15 45 293352and tempered) 4 100 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,
47、 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 10 250 160 000 1100 130 000 900 11 35 32138810 250 20 500 160 000 1100 130 000 900 11 35 321402A 668/A 668M 043at least twice this distance (2t) from any second surface.However, the tes
48、t depth shall not be nearer to one heat-treatedsurface than34 in. 19 mm and to the second heat treatedsurface than 112 in. 38 mm. Sketches showing the exact testlocations shall be approved by the purchaser when this methodis used.7.1.5 Tests for acceptance shall be made after final heattreatment of
49、the forgings.7.1.6 Test specimens shall be parallel to the axis of theforging in the direction in which the metal is most drawn outexcept that rings, hollow forgings which were expanded byforging, and disks shall be tested in the tangential direction.7.1.7 Yield point shall be determined on carbon steel GradesAthrough F, and yield strength on alloy steel Grades
