1、Designation: A983/A983M 06 (Reapproved 2016)Standard Specification forContinuous Grain Flow Forged Carbon and Alloy SteelCrankshafts for Medium Speed Diesel Engines1This standard is issued under the fixed designation A983/A983M; the number immediately following the designation indicates the yearof o
2、riginal 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 specification covers continuous grain flow forgedcarbo
3、n and alloy steel crankshafts for medium speed diesel andnatural gas engines.1.2 The steel used in the manufacture of the forgings isrequired to be vacuum degassed.1.3 The choice of steel composition grade for a givenstrength class is normally made by the forging supplier, unlessotherwise specified
4、by the purchaser.1.4 Provision is made for treatment of designated surfacesof the crankshaft to provide enhanced fatigue strength, or wearresistance, or both.1.5 Except as specifically required in this specification, allprovisions of Specification A788/A788M apply.1.6 Unless the order specifies the
5、applicable “M” specifica-tion designation, the material shall be furnished to the inch-pound units.1.7 The values stated in either inch-pound units or SI(metric) units are to be regarded separately as standard. Withinthe text and tables the SI units are shown in brackets. Thevalues stated in each sy
6、stem are not exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the specification.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel Produc
7、tsA503/A503M Specification for Ultrasonic Examination ofForged CrankshaftsA788/A788M Specification for Steel Forgings, General Re-quirementsA966/A966M Practice for Magnetic Particle Examination ofSteel Forgings Using Alternating CurrentA986/A986M Specification for Magnetic Particle Examina-tion of C
8、ontinuous Grain Flow Crankshaft ForgingsE45 Test Methods for Determining the Inclusion Content ofSteelE112 Test Methods for Determining Average Grain SizeE340 Practice for Macroetching Metals and Alloys2.2 Other Standards:AWS D1.1 Structural Welding Code3DIN 50 6024JIS G 0555 Microscopic Testing Met
9、hod for the Non-Metallic Inclusions in Steel53. Ordering Information3.1 In addition to the ordering requirements of SpecificationA788/A788M, the following items should be included:3.2 Choice of mechanical property class from Table 1.3.3 Choice of chemical composition Grade from Table 2 ifthis purcha
10、ser option is exercised (4.1.3).3.4 Whether surface hardening in designated areas isrequired, referencing Supplementary Requirements S10, S11,or S12, and providing the necessary instructions.3.5 For crankshafts designed to include welded counter-weights the purchaser may specify an alternate welding
11、 code toAWS D1.1 Structural Welding Code.3.6 For alternate tensile and hardness test requirementsspecify Supplementary Requirement S2.4. Materials and Manufacture4.1 Melting Practice:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and i
12、s the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1, 2016. Published April 2016. Originallyapproved in 1998. Last previous edition approved in 2011 as A983/A983M 06(2011). DOI: 10.1520/A0983_A0983M-06R16.2For referenced ASTM standards, vis
13、it 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.3Available from American Welding Society (AWS), 8669 NW 36 St., #130,Miami, FL 33166-6672, http:
14、/www.aws.org.4Available from Verlag Stahleisen Gmbh, Postfach 10 51 64, D-40042,Dsseldorf, Germany, http:/www.stahleisen.de.5Available from Japanese Standards Association (JSA), Mita MT Bldg., 3-13-12Mita, Minato-ku, Tokyo 108-0073, Japan, http:/www.jsa.or.jp.*A Summary of Changes section appears at
15、 the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.1 The steel making section of Specification A788/A788M shall apply together with mandatory vacuum degas-sing.4.1.2 Supplementary Requirement S1 may be used i
16、f non-metallic inclusion rating of the steel is required.4.1.3 Unless otherwise specified by the purchaser (3.2), theforging supplier shall select the chemical composition grade tobe used from Table 2.4.2 Forging:4.2.1 The use of bar from starting stock produced by slittinga rectangular section is n
17、ot permitted.4.2.2 The procedure used in forging the crankshaft shallensure that the centerline of the starting forged or rolled barwill follow the centerline contour of the main bearings, webs,and crankpins of the crankshaft.4.2.3 The grain flow present between adjacent main bearingjournals, webs,
18、and the intervening crankpin shall be demon-strated for the first article testing of a new crankshaft design bya given forging facility. This need not be repeated for othercrankshafts of the same design that differ from the first articlecrankshaft by the number of crankpin throws or, by agreementwit
19、h the purchaser, for V-Cylinder configurations of the sameengine. The axial grain flow shown after etching a centerlinelongitudinal section of the main bearing-web-crankpin-web-main bearing section shall be approved by the purchaser.Etching shall be done in accordance with Test Method E340.Using Sup
20、plementary Requirement S2, additional grain flowsections may be taken by agreement between the manufacturerand purchaser.4.3 Heat Treatment for Mechanical Properties:4.3.1 Heat treatment of crankshaft forgings may be doneeither before or after rough machining, at the manufacturersoption. By the use
21、of Supplementary Requirement S3 thepurchaser can specify that heat treatment be done after roughmachining.4.3.2 When counterweights are to be attached to the crank-shaft by welding (see 4.3.4), then the heat treatment formechanical properties shall follow after completion of thewelding. Intermediate
22、 post weld heat treatment may be appliedto the assembly at the manufacturers option.4.3.3 Heat treatment for mechanical properties shall consistof normalizing followed by tempering at a subcriticaltemperature, or austenitizing, liquid quenching and subcriticaltempering. A normalizing cycle may prece
23、de the austenitizingstage.4.3.3.1 The minimum tempering temperature shall be1100F 595C.4.3.4 If the crankshaft design includes attaching counter-weights to the webs by welding, then the manufacturer shallqualify the weld procedure and welders in accordance with awritten procedure acceptable to the p
24、urchaser. The procedureshall incorporate AWS specifications.4.3.5 If forgings receive thermal stress relief after comple-tion of heat treatment, then the stress relieving temperatureshall not exceed (T-50)F (T-30)C where T is the temperingtemperature. If this stress relieving temperature is exceeded
25、,then the mechanical testing required in Section 6 shall berepeated.4.3.6 If crankshaft counterweights are to be welded to thewebs, then the welding shall be done to a written, and qualifiedprocedure conforming to AWS D1.1 Structural Welding Codeor another similar welding code acceptable to the purc
26、haser.This procedure shall contain instructions concerning repair ofcounterweight welds, including preheat and post weld heattreatment requirements.5. Chemical Composition5.1 Heat AnalysisThe heat analysis obtained after sam-pling in accordance with Specification A788/A788M shallcomply with Table 2
27、for the chosen grade, and the require-ments agreed upon by Supplementary Requirement S4 if thiswas selected.6. Mechanical Requirements6.1 Tension Testing:TABLE 1 Tensile and Hardness RequirementsClass 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7Tensile Strength, ksi Mpa min 80 550 100 690 110 7
28、60 120 830 130 900 140 965 150 1035Yield Strength, (0.2% offset), ksi Mpa min 45 310 70 485 80 550 90 620 100 690 110 760 120 830Elongation, min % in 2 in. (4D) % in 62.5mm (5D)20 18 18 16 18 16 17 15 16 14 15 13 14 12Reduction of Area, % min 45 45 45 45 40 40 40Brinell Hardness, min 163 207 229 248
29、 262 285 302Brinell Hardness, max 217 255 269 293 302 331 341TABLE 2 Chemical Requirements Composition %Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 Grade 6 Grade 7 Grade 7A Grade 8 Grade 8ACarbon 0.43-0.53 0.43-0.52 0.28-0.33 0.38-0.48 0.30-0.48 0.35-0.45 0.28-0.35 0.380.48 0.30-0.35 0.380.48Manganese 0
30、.60-1.10 0.75-1.10 0.40-1.00 0.75-1.10 0.65-1.00 0.65-1.00 0.40-1.00 0.401.00 0.40-0.80 0.400.80Phosphorous 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 maxSulfur 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025 max 0.025
31、max 0.025 maxSilicon 0.15-0.40 0.15-0.40 0.15-0.40 0.15-0.40 0.15-0.40 0.15-0.40 0.15-0.40 0.150.40 0.15-0.40 0.150.40Nickel . . . . . . . . . . . . . . . . . . . . . . . . 1.30-1.70 1.301.70Chromium . . . 0.20-0.35 0.80-1.20 0.80-1.20 0.80-1.20 0.80-1.20 2.8-3.3 2.83.3 1.00-1.40 1.001.40Molybdenum
32、. . . 0.10 max 0.15-0.25 0.15-0.25 0.15-0.25 0.30-0.50 0.30-0.50 0.300.50 0.20-0.35 0.200.35Vanadium 0.10 max 0.10 max 0.10 max 0.10 max 0.10 max 0.10 max 0.10 max 0.10 max 0.15 max 0.15 maxA983/A983M 06 (2016)26.1.1 The heat treated forging shall comply with the require-ments of Table 1 for the sel
33、ected grade when tested inaccordance with this section. See also Test Methods andDefinitions A370. It should be noted that when the SI systemis specified the gauge length for the tension test shall bemeasured over a length of 5D.6.1.2 Test MaterialAn integral test prolongation equal indiameter to th
34、at of the starting bar diameter shall be providedat one end of each crankshaft subject to mechanical testing.6.1.3 SamplingThe longitudinal axis of the axially ori-ented tension test specimen shall be located at the mid-radiusposition in the integral crankshaft test prolongation. Supple-mentary Requ
35、irement S5 provides for a tension test prolonga-tion to be provided at both ends of the heat treated crankshaft,and Supplementary Requirement S6 provides for testing ofeach crankshaft in lieu of the test frequency specified inSupplementary Requirement S5.6.1.4 OrientationLongitudinal tension test sp
36、ecimensshall be taken from the crankshaft prolongation.6.1.5 Number of TestsUnless Supplementary Require-ments S5 or S6, or both, are specified, one tension testspecimen shall be tested to the requirements of Table 1, for theselected grade, at a frequency of one test per heat treatmentload.6.2 Impac
37、t TestingIf Charpy impact testing of the crank-shaft is required, Supplementary Requirement S7 shall bespecified.7. Grain Size7.1 The grain size of the forging following heat treatmentshall be ASTM 5 or finer when tested at the tension testlocation(s) in accordance with Test Methods E112.8. Surface
38、Hardening8.1 When required by the purchaser, and indicated in thecrankshaft drawing, the crankshaft shall be surface hardened indesignated areas for purposes of wear resistance and, when thebearing fillets are included, enhanced fatigue strength.8.2 The method and extent of the surface hardening sha
39、ll bespecified by the purchaser by including reference to Supple-mentary Requirements S9 (nitriding), S10 (induction harden-ing of the bearing journals), or S11 (full induction hardening ofbearing journals and fillets).9. Nondestructive Examination9.1 Because ac magnetizing equipment is required to
40、beused, the magnetic particle examination of the crankshaft shallbe done on completion of all machining operations. Theexamination shall be in accordance with Practice A966/A966M.9.1.1 Acceptance criteria for the magnetic particle exami-nation shall be in accordance with Specification A986/A986M.9.2
41、 Supplementary Requirement S8 shall be specified ifultrasonic examination of the crankshaft bar or the crankshaftforging is required.10. Workmanship10.1 In addition to the specific order or drawing require-ments for surface finish, the general appearance with respect tosoundness and finish shall be
42、consistent with good crankshaftpractice, as determined by ordinary visual inspection.11. Certification11.1 When certification of a crankshaft includes inspectionby a classification agency, the manufacturer shall be notified ofthis provision, so that arrangements can be made to allow forwitnessing of
43、 such manufacturing and testing operations asneeded.12. Delivery12.1 In addition to the requirements of Specification A788/A788M, the purchaser shall notify the producer on any specialcorrosion protection and packing instructions. SupplementaryRequirement S12 may be used to call for specific packing
44、instructions, otherwise the producers normal product protec-tion practices shall apply.13. Keywords13.1 crankshafts, continuous grain flow; medium speeddiesel engines; steel forgings; surface hardeningSUPPLEMENTARY REQUIREMENTSOne or more of the following supplementary requirements shall apply only
45、when specified by thepurchaser in the inquiry or order. Details of these supplementary requirements shall be agreed uponby the manufacturer and the purchaser.S1. Nonmetallic Inclusion RatingS1.1 The nonmetallic inclusion rating for steel bars orbillets to be used for making CGF crankshafts shall be
46、done inaccordance with an agreed upon practice, or one of thefollowing standards: Test Methods E45Method D, DIN 50602, or JIS G 0555.S1.2 The acceptance criteria for the nonmetallic inclusionrating shall be specified by the purchaser.S2. Alternate Tensile and Hardness RequirementsS2.1 The purchaser
47、shall specify alternate tensile strengthand hardness requirements to those specified in Table 1.A983/A983M 06 (2016)3S2.2 The alternate tensile strength values shall be interpo-lated from the values given in Table 1. For strength levelshigher than Class 7 in Table 1 the requirements shall be agreedb
48、etween the purchaser and the manufacturer.S2.3 The alternate hardness values shall be interpolatedfrom the values given in Table 1, but shall be in increments of0.05 mm.S3. Machining Before Heat TreatmentS3.1 Forgings shall be rough machined to agreed upondimensions prior to heat treatment for mecha
49、nical properties.S4. Additional Chemical ElementsS4.1 In addition to the elements specified in Table 2 for aspecific grade, additional elements shall be added to the steelwithin ranges agreed upon between manufacturer and pro-ducer.S4.2 The chemical analysis of the modified grade shall bereported as required by the certification section.S5. Mechanical TestingS5.1 For each crankshaft, tension testing at the prolongationmid-radius position shall be done at both ends of the crank-shaft. A heat treatment
