ASTM A756-94(2001)

Standard Specification for Stainless Anti-Friction Bearing Steel

ABSTRACT
This specification deals with the requirements for chromium-carbon bearing quality stainless steel to be used in the manufacture of anti-friction bearings. Chemical requirements shall conform to the required compositions of carbon, manganese, phosphorus, sulfur, silicon, chromium, nickel, copper, and molybdenum. Heat analysis and product analysis shall made. Decarburization and surface imperfection limits are specified. When annealing will be made, the steel should have a completely spheroidized microstructure and the hardness is specified.
SCOPE
1.1 This specification covers the requirements for chromium-carbon bearing quality stainless steel to be used in the manufacture of anti-friction bearings.
1.2 Supplementary Requirements of an optional nature are provided and when desired shall be so stated in the order.
1.3 The values stated in inch-pound units are to be regarded as the standard.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• ICS: 77.140.20 - Stainless steels
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.28 - Bearing and Power Transmission Steels

Relations

• Replaces: ASTM A756-94 - Standard Specification for Stainless Anti-Friction Bearing Steel
• Effective Date: 01-Jan-2001
• Replaced By: ASTM A756-09 - Standard Specification for Stainless Anti-Friction Bearing Steel
• Effective Date: 01-Oct-2009
• Referred By: ASTM F2332-06(2022) - Standard Specification for Annular Ball Bearings for Instruments and Precision Rotating Components
• Effective Date: 01-Jan-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation: A756 – 94 (Reapproved 2001)
Standard Specification for
Stainless Anti-Friction Bearing Steel
This standard is issued under the fixed designation A756; 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 3.1.3 Specification designation and year of issue,
3.1.4 Dimensions, shape, and
1.1 This specification covers the requirements for
3.1.5 Supplementary Requirements, if desired.
chromium-carbon bearing quality stainless steel to be used in
the manufacture of anti-friction bearings.
4. Process
1.2 Supplementary Requirements of an optional nature are
4.1 The steel shall be made by a process that is capable of
provided and when desired shall be so stated in the order.
providing a high-quality product meeting the requirements of
1.3 The values stated in inch-pound units are to be regarded
this specification.
as the standard.
5. Chemical Composition
2. Referenced Documents
2 5.1 Typical examples of chemical compositions are shown
2.1 ASTM Standards:
in Table 1. Other compositions may be specified.
A484/A484M Specification for General Requirements for
5.2 An analysis of each heat of steel shall be made by the
Stainless Steel Bars, Billets, and Forgings
steel manufacturer in accordance withTest MethodsA751.The
A751 Test Methods, Practices, andTerminology for Chemi-
chemical composition thus determined shall conform to the
cal Analysis of Steel Products
requirements specified in Table 1 for the ordered grade or to
E45 Test Methods for Determining the Inclusion Content of
requirements agreed upon between the manufacturer and the
Steel
purchaser.
E381 Method of Macroetch Testing Steel Bars, Billets,
5.3 Product analysis may be made by the purchaser in
Blooms, and Forgings
accordance with Test MethodsA751. Permissible variations in
E1019 Test Methods for Determination of Carbon, Sulfur,
product analysis shall be made in accordance with Specifica-
Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt
tion A484/A484M.
Alloys by Various Combustion and Fusion Techniques
E1077 Test Methods for Estimating the Depth of Decarbur-
6. Dimensions, Mass, and Permissible Variations
ization of Steel Specimens
6.1 The size and shape of the material shall be agreed upon
2.2 Other Standard:
between manufacturer and purchaser.
SAE J418a Grain Size Determination of Steel
6.2 Dimensional tolerances for hot-rolled or hot-rolled and
annealed bars, in straight lengths or coils, and cold-finished
3. Ordering Information
bars0.500in.(12.7mm)andlargerindiameterfurnishedunder
3.1 Orders for material under specification should include
thisspecificationshallconformtotherequirementsspecifiedin
the following information:
the latest edition of Specification A484/A484M.
3.1.1 Quantity,
6.3 Dimensional tolerances for cold-finished coils for ball
3.1.2 Grade identification,
and roller material shall be as shown in Table 2.
6.4 Coil tolerances also apply to cold-finished straight
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
lengths under 0.500 in. (12.7 mm) in diameter.
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.28 on Bearing Steels.
7. Quality Tests
Current edition approved March 10, 2001. Published March 2001. Originally
published as A756–78. Last previous edition A756 – 94. DOI: 10.1520/A0756- 7.1 The supplier shall be held responsible for the quality of
94R01.
the material furnished and shall make the necessary tests to
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ensure this quality. The supplier shall be required to report on
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the results of the macroetch and microinclusion rating tests
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
detailed below. Quality tests shown in 7.2 through 7.4 are
Available from Society of Automotive Engineers, 400 Commonwealth Drive,
based upon procedures established in Test Methods E45.
Warrendale, PA 15096.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A756 – 94 (2001)
TABLE 1 Chemical Composition
between configurations shown on the chart shall be classified
Element 440C 440C MOD as the lesser of the rating number. The worst field of each
inclusion type from each specimen shall be recorded as the
Carbon 0.95 to 1.10 1.00 to 1.10
Manganese, max 1.00 0.30 to 1.00
ratingforthespecimen.Twothirdsofallspecimensandatleast
Phosphorus, max 0.025 0.025
one from each ingot tested, as well as the average of all
Sulfur, max 0.025 0.025
specimens, shall not exceed the rating specified in Table 3.
Silicon, max 1.00 0.20 to 1.00
Chromium 16.00 to 18.00 13.00 to 15.00
Nickel, max 0.75 0.75
8. Response to Heat Treatment
Copper, max 0.50 0.50
8.1 Specimens with sections ⁄8 in. (9.5 mm) in thickness,
Molybdenum 0.40 to 0.65 3.75 to 4.25
cut from a bar, billet, or forging, shall be placed in a furnace
that is at 1875 6 10°F (1023.8 6 5.5°C), allowed to heat to
TABLE 2 Dimensional Tolerances for Cold-Finished Coils
1875 6 10°F, held at heat 25 min, and cooled in still air.
Hardness of such specimens shall be not lower than 58 HRC.
Size, in. (mm) Total Tolerance, in. (mm)
8.2 Samplesheattreatedasin8.1shallshowafracturegrain
Through 0.096 (2.44) 0.002 (0.05)
Over 0.096 to 0.270 (2.44 to 6.86), incl 0.003 (0.08) size of No. 6 or finer. (See SAE J418a.)
Over 0.270 to 0.750 (6.86 to 19.1), incl 0.004 (0.10)
9. Decarburization and Surface Imperfections
9.1 Decarburization and surface imperfections shall not
exceed the limits specified in Table 4 and Table 5. Decarbur-
7.2 Sampling—Samples taken in accordance with the fol-
ization shall be measured using the microscopical methods
lowing paragraphs shall be obtained from 4 by 4-in. (102 by
102-mm) rolled billets or forged sections. Tests may be made described in Test Methods E1077.
on smaller or larger sections by agreement with the purchaser.
10. Microstructure and Hardness
Aminimum 3 to 1 reduction of rolled billets or forged sections
10.1 The material shall be free of excessive carbide segre-
is required for strand cast products.
gation.
7.2.1 For top poured products, a minimum of six samples
10.2 When annealing is specified in the order, the steel shall
representing the top and bottom of first, middle, and last usable
have a completely spheroidized microstructure and a hardness
ingots shall be examined.
as specified in Table 6.
7.2.2 For bottom poured products, a minimum of six
10.3 Small sizes where Rockwell B scale hardness readings
samples shall be examined and they shall represent the top and
are impractical shall show a maximum tensile strength of
bottom of three ingots. One ingot shall be taken at random
115 000 psi (792 mPa).
from the first usable plate poured, one ingot, at random, from
the usable plate poured nearest to the middle of
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