ASTM A983/A983M-06(2011)
(Specification)Standard Specification for Continuous Grain Flow Forged Carbon and Alloy Steel Crankshafts for Medium Speed Diesel Engines
Standard Specification for Continuous Grain Flow Forged Carbon and Alloy Steel Crankshafts for Medium Speed Diesel Engines
ABSTRACT
This specification deals with continuous grain flow carbon and alloy steel crankshaft forgings intended for medium speed diesel and natural gas engines. The steel used in the manufacture of the forgings is required to be vacuum degassed. Heat treatment, which may be done either before or after rough machining, shall consist of normalizing followed by tempering at a subcritical temperature, or austenitizing, liquid quenching and subcritical tempering. Charpy impact and tensile tests, which shall be performed at a frequency of one test per heat treatment load, shall be used to evaluate tensile strength, yield strength, elongation, reduction of area, and Brinell hardness requirements of forgings. Chemical composition requirements shall also be examined by heat analysis. Grain size tests and non-destructive magnetic particle examinations shall be conducted as well. When required by the purchaser, crankshafts may be surface hardened in designated areas for the purposes of enhanced wear resistance and fatigue strength.
SCOPE
1.1 This specification covers continuous grain flow forged carbon and alloy steel crankshafts for medium speed diesel and natural gas engines.
1.2 The steel used in the manufacture of the forgings is required to be vacuum degassed.
1.3 The choice of steel composition grade for a given strength class is normally made by the forging supplier, unless otherwise specified by the purchaser.
1.4 Provision is made for treatment of designated surfaces of the crankshaft to provide enhanced fatigue strength, or wear resistance, or both.
1.5 Except as specifically required in this specification, all provisions of Specification A788/A788M apply.
1.6 Unless the order specifies the applicable “M” specification 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. Within the text and tables the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:A983/A983M −06(Reapproved 2011)
Standard Specification for
Continuous Grain Flow Forged Carbon and Alloy Steel
Crankshafts for Medium Speed Diesel Engines
This standard is issued under the fixed designationA983/A983M; the number immediately following the designation indicates the year
of 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.
1. Scope* A788/A788M Specification for Steel Forgings, General Re-
quirements
1.1 This specification covers continuous grain flow forged
A966/A966M Practice for Magnetic Particle Examination of
carbon and alloy steel crankshafts for medium speed diesel and
Steel Forgings Using Alternating Current
natural gas engines.
A986/A986M Specification for Magnetic Particle Examina-
1.2 The steel used in the manufacture of the forgings is
tion of Continuous Grain Flow Crankshaft Forgings
required to be vacuum degassed.
E45 Test Methods for Determining the Inclusion Content of
Steel
1.3 The choice of steel composition grade for a given
strength class is normally made by the forging supplier, unless E112 Test Methods for Determining Average Grain Size
E340 Test Method for Macroetching Metals and Alloys
otherwise specified by the purchaser.
2.2 Other Standards:
1.4 Provision is made for treatment of designated surfaces
AWS D1.1 Structural Welding Code
of the crankshaft to provide enhanced fatigue strength, or wear
DIN 50 602
resistance, or both.
JIS G 0555 Microscopic Testing Method for the Non-
1.5 Except as specifically required in this specification, all
Metallic Inclusions in Steel
provisions of Specification A788/A788M apply.
3. Ordering Information
1.6 Unless the order specifies the applicable “M” specifica-
tion designation, the material shall be furnished to the inch-
3.1 In addition to the ordering requirements of Specification
pound units. A788/A788M, the following items should be included:
1.7 The values stated in either inch-pound units or SI
3.2 Choice of mechanical property class from Table 1.
(metric) units are to be regarded separately as standard. Within
3.3 Choice of chemical composition Grade from Table 2 if
the text and tables the SI units are shown in brackets. The
this purchaser option is exercised (4.1.3).
values stated in each system are not exact equivalents;
3.4 Whether surface hardening in designated areas is
therefore,eachsystemshallbeusedindependentlyoftheother.
required, referencing Supplementary Requirements S10, S11,
Combining values from the two systems may result in noncon-
or S12, and providing the necessary instructions.
formance with the specification.
3.5 For crankshafts designed to include welded counter-
2. Referenced Documents
weightsthepurchasermayspecifyanalternateweldingcodeto
2.1 ASTM Standards: AWS D1.1 Structural Welding Code.
A370 Test Methods and Definitions for Mechanical Testing
3.6 For alternate tensile and hardness test requirements
of Steel Products
specify Supplementary Requirement S2.
A503/A503M Specification for Ultrasonic Examination of
Forged Crankshafts
4. Materials and Manufacture
4.1 Melting Practice:
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.06 on Steel Forgings and Billets. Available from American Welding Society, 550 NW Le Jeune Rd., Miami, FL
Current edition approved April 1, 2011. Published June 2011. Originally 33126.Available from American Welding Society (AWS), 550 NW LeJeune Rd.,
approved in 1998. Last previous edition approved in 2006 as A983/A983M – 06. Miami, FL 33126, http://www.aws.org.
DOI: 10.1520/A0983_A0983M-06R11. Available from Verlag Stahleisen mbh, Postfach 8229, D-4000 Dusseldorf,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Germany.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from Japanese Standards Association, 1-24 Akasaka 4, Minato-Ku,
Standards volume information, refer to the standard’s Document Summary page on Tokyo 107, Japan.Available from Japanese Standards Organization (JSA), 4-1-24
the ASTM website. Akasaka Minato-Ku, Tokyo, 107-8440, Japan, http://www.jsa.or.jp.
*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
A983/A983M−06 (2011)
TABLE 1 Tensile and Hardness Requirements
Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
Tensile Strength, ksi [Mpa] min 80 [550] 100 [690] 110 [760] 120 [830] 130 [900] 140 [965] 150 [1035]
Yield Strength, (0.2% offset), ksi [Mpa] min 45 [310] 70 [485] 80 [550] 90 [620] 100 [690] 110 [760] 120 [830]
Elongation, min % in 2 in. (4D) [% in 62.5 20 [18] 18 [16] 18 [16] 17 [15] 16 [14] 15 [13] 14 [12]
mm] (5D)
Reduction of Area, % min 45 45 45 45 40 40 40
Brinell Hardness, min 163 207 229 248 262 285 302
Brinell Hardness, max 217 255 269 293 302 331 341
TABLE 2 Chemical Requirements Composition %
Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 Grade 6 Grade 7 Grade 7A Grade 8 Grade 8A
Carbon 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 0.38–0.48 0.30-0.35 0.38–0.48
Manganese 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 0.40–1.00 0.40-0.80 0.40–0.80
Phosphorous 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 max
Sulfur 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 max
Silicon 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 0.15–0.40 0.15-0.40 0.15–0.40
Nickel . . . . . . . . . . . . . . . . . . . . . . . . 1.30-1.70 1.30–1.70
Chromium . . . 0.20-0.35 0.80-1.20 0.80-1.20 0.80-1.20 0.80-1.20 2.8-3.3 2.8–3.3 1.00-1.40 1.00–1.40
Molybdenum . . . 0.10 max 0.15-0.25 0.15-0.25 0.15-0.25 0.30-0.50 0.30-0.50 0.30–0.50 0.20-0.35 0.20–0.35
Vanadium 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 max
4.1.1 The steel making section of Specification A788/ welding. Intermediate post weld heat treatment may be applied
A788M shall apply together with mandatory vacuum degas- to the assembly at the manufacturer’s option.
sing.
4.3.3 Heat treatment for mechanical properties shall consist
4.1.2 Supplementary Requirement S1 may be used if non-
of normalizing followed by tempering at a subcritical
metallic inclusion rating of the steel is required.
temperature, or austenitizing, liquid quenching and subcritical
4.1.3 Unless otherwise specified by the purchaser (3.2), the
tempering. A normalizing cycle may precede the austenitizing
forging supplier shall select the chemical composition grade to
stage.
be used from Table 2.
4.3.3.1 The minimum tempering temperature shall be
1100°F [595°C].
4.2 Forging:
4.2.1 The use of bar from starting stock produced by slitting 4.3.4 If the crankshaft design includes attaching counter-
a rectangular section is not permitted.
weights to the webs by welding, then the manufacturer shall
4.2.2 The procedure used in forging the crankshaft shall qualify the weld procedure and welders in accordance with a
ensure that the centerline of the starting forged or rolled bar
written procedure acceptable to the purchaser. The procedure
will follow the centerline contour of the main bearings, webs, shall incorporate AWS specifications.
and crankpins of the crankshaft.
4.3.5 If forgings receive thermal stress relief after comple-
4.2.3 The grain flow present between adjacent main bearing
tion of heat treatment, then the stress relieving temperature
journals, webs, and the intervening crankpin shall be demon-
shall not exceed (T-50)°F [(T-30)°C] where T is the tempering
strated for the first article testing of a new crankshaft design by
temperature. If this stress relieving temperature is exceeded,
a given forging facility. This need not be repeated for other
then the mechanical testing required in Section 6 shall be
crankshafts of the same design that differ from the first article
repeated.
crankshaft by the number of crankpin throws or, by agreement
4.3.6 If crankshaft counterweights are to be welded to the
with the purchaser, for V-Cylinder configurations of the same
webs, then the welding shall be done to a written, and qualified
engine. The axial grain flow shown after etching a centerline
procedure conforming to AWS D1.1 Structural Welding Code
longitudinal section of the main bearing-web-crankpin-web-
or another similar welding code acceptable to the purchaser.
main bearing section shall be approved by the purchaser.
This procedure shall contain instructions concerning repair of
Etching shall be done in accordance with Test Method E340.
counterweight welds, including preheat and post weld heat
Using Supplementary Requirement S2, additional grain flow
treatment requirements.
sections may be taken by agreement between the manufacturer
and purchaser.
5. Chemical Composition
4.3 Heat Treatment for Mechanical Properties:
5.1 Heat Analysis—The heat analysis obtained after sam-
4.3.1 Heat treatment of crankshaft forgings may be done
pling in accordance with Specification A788/A788M shall
either before or after rough machining, at the manufacturer’s
comply with Table 2 for the chosen grade, and the require-
option. By the use of Supplementary Requirement S3 the
ments agreed upon by Supplementary Requirement S4 if this
purchaser can specify that heat treatment be done after rough
was selected.
machining.
4.3.2 When counterweights are to be attached to the crank-
6. Mechanical Requirements
shaft by welding (see 4.3.4), then the heat treatment for
mechanical properties shall follow after completion of the 6.1 Tension Testing:
A983/A983M−06 (2011)
6.1.1 Theheattreatedforgingshallcomplywiththerequire- mentary Requirements S9 (nitriding), S10 (induction harden-
ments of Table 1 for the selected grade when tested in ing of the bearing journals), or S11 (full induction hardening of
accordance with this section. See also Test Methods and bearing journals and fillets).
Definitions A370. It should be noted that when the SI system
9. Nondestructive Examination
is specified the gauge length for the tension test shall be
measured over a length of 5D.
9.1 Because ac magnetizing equipment is required to be
6.1.2 Test Material—An integral test prolongation equal in
used, the magnetic particle examination of the crankshaft shall
diameter to that of the starting bar diameter shall be provided
be done on completion of all machining operations. The
at one end of each crankshaft subject to mechanical testing.
examination shall be in accordance with Test Method A966/
6.1.3 Sampling—The longitudinal axis of the axially ori-
A966M.
ented tension test specimen shall be located at the mid-radius
9.1.1 Acceptance criteria for the magnetic particle exami-
position in the integral crankshaft test prolongation. Supple-
nation shall be in accordance with Specification A986/A986M.
mentary Requirement S5 provides for a tension test prolonga-
9.2 Supplementary Requirement S8 shall be specified if
tion to be provided at both ends of the heat treated crankshaft,
ultrasonic examination of the crankshaft bar or the crankshaft
and Supplementary Requirement S6 provides for testing of
forging is required.
each crankshaft in lieu of the test frequency specified in
Supplementary Requirement S5.
10. Workmanship
6.1.4 Orientation—Longitudinal tension test specimens
10.1 In addition to the specific order or drawing require-
shall be taken from the crankshaft prolongation.
ments for surface finish, the general appearance with respect to
6.1.5 Number of Tests—Unless Supplementary Require-
soundness and finish shall be consistent with good crankshaft
ments S5 or S6, or both, are specified, one tension test
practice, as determined by ordinary visual inspection.
specimen shall be tested to the requirements of Table 1, for the
selected grade, at a frequency of one test per heat treatment
11. Certification
load.
11.1 When certification of a crankshaft includes inspection
6.2 Impact Testing—If Charpy impact testing of the crank-
by a classification agency, the manufacturer shall be notified of
shaft is required, Supplementary Requirement S7 shall be
this provision, so that arrangements can be made to allow for
specified.
witnessing of such manufacturing and testing operations as
needed.
7. Grain Size
12. Delivery
7.1 The grain size of the forging following heat treatment
shall be ASTM 5 or finer when tested at the tension test
12.1 In addition to the requirements of Specification A788/
location(s) in accordance with Test Methods E112.
A788M, the purchaser shall notify the producer on any special
corrosion protection and packing instructions. Supplementary
8. Surface Hardening
Requirement S12 may be used to call for specific packing
8.1 When required by the purchaser, and indicated in the
instructions, otherwise the producer’s normal product protec-
crankshaft drawing, the crankshaft shall be surface hardened in
tion practices shall apply.
designated areas for purposes of wear resistance and, when the
bearing fillets are included, enhanced fatigue strength. 13. Keywords
8.2 The method and extent of the surface hardening shall be 13.1 crankshafts, continuous grain flow; medium speed
specified by the purchaser by including reference to Supple- diesel engines; steel forgings; surface hardening
SUPPLEMENTARY REQUIREMENTS
One or more of the following supplementary requirements shall apply only when specified by the
purchaser in the inquiry or order. Details of these supplementary requirements shall be agreed upon
by the manufacturer and the purchaser.
S1. Nonmetallic Inclusion Rating S1.2 The acceptance criteria for the nonmetallic inclusion
rating shall be specified by the purchaser.
S1.1 The nonmetallic inclusion rating for steel bars or
billets to be used for making CGF crankshafts shall be done in
S2. Alternate Tensile and Hardness Requirements
accordance with an agreed upon practice, or one of the
following standards: Test Methods E45—Method D, DIN 50 S2.1 The purchaser shall specify alternate tensile strength
602, or JIS G 0555. and hardness requirements to those specified in Table 1.
A983/A983M−06 (2011)
S2.2 The alternate tensile strength values shall be interpo- S9. Surface Nitriding
lated from the values given in Table 1. For strength levels
S9.1 The surfaces designated in the crankshaft drawing
higher than Class 7 in Table 1 the requirements shall be agreed
shall be nitrided. Significant details such as the surfac
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