1、Designation: A 983/A 983M 06Standard Specification forContinuous Grain Flow Forged Carbon and Alloy SteelCrankshafts for Medium Speed Diesel Engines1This standard is issued under the fixed designation A 983/A 983M; the number immediately following the designation indicates the yearof original adopti
2、on 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.1. Scope*1.1 This specification covers continuous grain flow forgedcarbon and alloy s
3、teel 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 by the purcha
4、ser.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 A 788/A 788M apply.1.6 Unless the order specifies the applicable
5、“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 system are no
6、t exact equivalents; there-fore, 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:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 503/
7、A 503M Specification for Ultrasonic Examination ofForged CrankshaftsA 788/A 788M Specification for Steel Forgings, GeneralRequirementsA 966/A 966M Test Method for Magnetic Particle Exami-nation of Steel Forgings Using Alternating CurrentA 986/A 986M Specification for Magnetic Particle Exami-nation o
8、f Continuous Grain Flow Crankshaft ForgingsE45 Test Methods for Determining the Inclusion Contentof SteelE112 Test Methods for Determining Average Grain SizeE 340 Test Method for Macroetching Metals and Alloys2.2 Other Standards:AWS D1.1 Structural Welding Code3DIN 50 6024JIS G 0555 Microscopic Test
9、ing Method for the Non-Metallic Inclusions in Steel53. Ordering Information3.1 In addition to the ordering requirements of SpecificationA 788/A 788M, 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 ifth
10、is purchaser option is exercised (4.1.3).3.4 Whether surface hardening in designated areas is re-quired, referencing Supplementary Requirements S10, S11, orS12, and providing the necessary instructions.3.5 For crankshafts designed to include welded counter-weights the purchaser may specify an altern
11、ate welding 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:4.1.1 The steel making section of Specification A 788/A 788M shall apply together with mandatory vacuum de
12、gas-sing.4.1.2 Supplementary Requirement S1 may be used if non-metallic inclusion rating of the steel is required.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
13、nd Billets.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 1998. Last previous edition approved in 2005 as A 983/A 983M 05.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Welding Society, 550 NW Le Jeune Rd., Miami, FL33126.4Available from Verlag Stahleisen mbh, Postfach 8229, D-4000 Dusseldorf,Germany.5Available from Japanese Standards Assoc
15、iation, 1-24 Akasaka 4, Minato-Ku,Tokyo 107, Japan.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.4.1.3 Unless otherwise specified by the purchaser (3.2), theforging
16、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 not permitted.4.2.2 The procedure used in forging the crankshaft shallensure that the centerline of the starting forged or rol
17、led 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, and the intervening crankpin shall be demon-strated for the first article testing of a new crankshaft design bya given forgin
18、g 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 agreementwith the purchaser, for V-Cylinder configurations of the sameengine. The axial grain flow shown after etching a centerlinelongit
19、udinal 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 E 340.Using Supplementary Requirement S2, additional grain flowsections may be taken by agreement between the manufacturerand purchaser.4.3
20、 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 of Supplementary Requirement S3 thepurchaser can specify that heat treatment be done after roughmachining.4.3.2 When counter
21、weights 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 post weld heat treatment may be appliedto the assembly at the manufacturers option.4.3.3 Heat treatment for mechanical prop
22、erties shall consistof normalizing followed by tempering at a subcritical tempera-ture, or austenitizing, liquid quenching and subcritical temper-ing. A normalizing cycle may precede the austenitizing stage.4.3.3.1 The minimum tempering temperature shall be1100F 595C.4.3.4 If the crankshaft design i
23、ncludes 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 purchaser. The procedureshall incorporate AWS specifications.4.3.5 If forgings receive thermal stress relief after compl
24、e-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,then the mechanical testing required in Section 6 shall berepeated.4.3.6 If crankshaft counterweights are to be welded
25、 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 purchaser.This procedure shall contain instructions concerning repair ofcounterweight welds, including preheat and post wel
26、d heattreatment requirements.5. Chemical Composition5.1 Heat AnalysisThe heat analysis obtained after sam-pling in accordance with Specification A 788/A 788M shallcomply with Table 2 for the chosen grade, and the requirementsagreed upon by Supplementary Requirement S4 if this wasselected.6. Mechanic
27、al Requirements6.1 Tension Testing:6.1.1 The heat treated forging shall comply with the require-ments of Table 1 for the selected grade when tested inaccordance with this section. See also Test Methods andDefinitions A 370. It should be noted that when the SI systemTABLE 1 Tensile and Hardness Requi
28、rementsClass 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7Tensile Strength, ksi Mpa min 80 550 100 690 110 760 120 830 130 900 140 965 150 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
29、 18 16 17 15 16 14 15 13 14 12Reduction of Area, % min 45 45 45 45 40 40 40Brinell Hardness, min 163 207 229 248 262 285 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 8ACar
30、bon 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 0.60-1.10 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
31、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 max 0.025 maxSilicon 0.15-0.40 0.15-0.40 0.15-0.040 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 1.30
32、1.70Chromium . . . 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 . . . 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
33、maxA 983/A 983M 062is 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 that of the starting bar diameter shall be providedat one end of each crankshaft subject to mechanical testing.6.1.3 Samplin
34、gThe 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 Requirement S5 provides for a tension test prolonga-tion to be provided at both ends of the heat treated crankshaft,and Supple
35、mentary Requirement S6 provides for testing ofeach crankshaft in lieu of the test frequency specified inSupplementary Requirement S5.6.1.4 OrientationLongitudinal tension test specimensshall be taken from the crankshaft prolongation.6.1.5 Number of TestsUnless Supplementary Require-ments S5 or S6, o
36、r 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 Impact TestingIf Charpy impact testing of the crank-shaft is required, Supplementary Requirement S7 shall bespecified.7. Grain
37、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 Hardening8.1 When required by the purchaser, and indicated in thecrankshaft drawing, the crankshaft shall be surface harde
38、ned 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 shall bespecified by the purchaser by including reference to Supple-mentary Requirements S9 (nitriding), S10 (induction harde
39、n-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 beused, the magnetic particle examination of the crankshaft shallbe done on completion of all machining operations. Theexa
40、mination shall be in accordance with Test Method A 966/A 966M.9.1.1 Acceptance criteria for the magnetic particle exami-nation shall be in accordance with Specification A 986/A 986M.9.2 Supplementary Requirement S8 shall be specified ifultrasonic examination of the crankshaft bar or the crankshaftfo
41、rging 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 consistent with good crankshaftpractice, as determined by ordinary visual inspection.11. Certification11.1 When cer
42、tification 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 such manufacturing and testing operations asneeded.12. Delivery12.1 In addition to the requirements of Specificati
43、on A 788/A 788M, the purchaser shall notify the producer on any specialcorrosion protection and packing instructions. SupplementaryRequirement S12 may be used to call for specific packinginstructions, otherwise the producers normal product protec-tion practices shall apply.13. Keywords13.1 crankshaf
44、ts, continuous grain flow; medium speeddiesel engines; steel forgings; surface hardeningSUPPLEMENTARY REQUIREMENTSOne or more of the following supplementary requirements shall apply only when specified by thepurchaser in the inquiry or order. Details of these supplementary requirements shall be agre
45、ed 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 done inaccordance with an agreed upon practice, or one of thefollowing standards: Test Methods E45Method D, DIN 5
46、0602,orJIS 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 shall specify alternate tensile strengthand hardness requirements to those specified in Table 1.S2.2 The alternate
47、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 agreedbetween the purchaser and the manufacturer.A 983/A 983M 063S2.3 The alternate hardness values shall be interpolatedfrom the values given
48、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 mechanical properties.S4. Additional Chemical ElementsS4.1 In addition to the elements specified in Table 2 for aspecific gra
49、de, 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 weight, excluding test prolongations, inexcess of 6000 lb 3000 kg may be specified by the purchaseras the point at which te
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