ASTM A914/A914M-19
(Specification)Standard Specification for Steel Bars Subject to Restricted End-Quench Hardenability Requirements
Standard Specification for Steel Bars Subject to Restricted End-Quench Hardenability Requirements
ABSTRACT
This specification covers hot-worked alloy and carbon-boron steels designed to attain restricted depth of hardening in the end-quench test. These steel compositions are identified by the suffix letter “RH” added to the conventional grade number. The steel shall be made by one or more of the following primary processes: open-hearth, basic-oxygen, or electric furnace. The primary melting may incorporate separate degassing or ladle refining and may be followed by secondary melting using electroslag remelting or vacuum arc remelting. Where secondary melting is employed, the heat shall be defined as all the ingots remelted from a single primary heat. Immediately after hot working, the bars shall be allowed to cool when necessary to a temperature below the critical range under suitable conditions, to prevent injury by too rapid cooling. The steel shall have an austenitic grain size of five to eight. The grain structure shall be considered satisfactory when a minimum of 70% of the rated grains are within the specified size limits. Hardenability values specified are based on fine-grain steels and are not applicable to coarse-grain steel. All forged and rolled hardenability test specimens must be normalized prior to testing. Cast specimens need not be normalized.
SCOPE
1.1 This specification covers hot-worked alloy and carbon-boron steels designed to attain restricted depth of hardening in the end-quench test. These steel compositions are identified by the suffix letter “RH” added to the conventional grade number.
1.2 In general, steels with restricted hardenability (RH steels) will exhibit a hardness range not greater than 5 HRC at the initial position on the end-quench hardenability bar and not greater than 65 % of the hardness range for standard H-band steels (Specification A304) in the inflection region. Generally the restricted hardenability band follows the middle of the corresponding standard H-band. An example of the RH band compared with the H band is given for Grade 4140 in Fig. 1.
FIG. 1 Comparison of H-Band and RH-Band for 4140 SteelA
1.2.1 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.3 This specification is expressed in both inch-pound units and SI units. However, the material will be supplied to inch-pound units unless the purchase order specifies the “M” specification designation.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:A914/A914M −19
Standard Specification for
Steel Bars Subject to Restricted End-Quench Hardenability
1
Requirements
This standard is issued under the fixed designationA914/A914M; 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* A29/A29M SpecificationforGeneralRequirementsforSteel
Bars, Carbon and Alloy, Hot-Wrought
1.1 This specification covers hot-worked alloy and carbon-
A255 Test Methods for Determining Hardenability of Steel
boron steels designed to attain restricted depth of hardening in
A304 Specification for Carbon andAlloy Steel Bars Subject
the end-quench test. These steel compositions are identified by
to End-Quench Hardenability Requirements
the suffix letter “RH” added to the conventional grade number.
E112 Test Methods for Determining Average Grain Size
1.2 In general, steels with restricted hardenability (RH 3
2.2 SAE Standards:
steels) will exhibit a hardness range not greater than 5 HRC at
J 406 Methods of Determining Hardenability of Steels
the initial position on the end-quench hardenability bar and not
J 1268 Hardenability Bands for Carbon and Alloy H Steels
greater than 65 % of the hardness range for standard H-band
J 1868 Restricted Hardenability Bands for Selected Alloy
steels (Specification A304) in the inflection region. Generally
Steels
the restricted hardenability band follows the middle of the
corresponding standard H-band. An example of the RH band
3. Terminology
compared with the H band is given for Grade 4140 in Fig. 1.
3.1 Definitions of Terms Specific to This Standard:
1.2.1 ThevaluesstatedineitherSIunitsorinch-poundunits
3.1.1 hardenability—the relative ability of a steel to harden
are to be regarded separately as standard. The values stated in
under heat treatment becomes apparent in the degree to which
each system may not be exact equivalents; therefore, each
the material hardens when quenched at different cooling rates.
system shall be used independently of the other. Combining
3.1.1.1 Discussion—Hardenability is measured
values from the two systems may result in non-conformance
quantitatively, usually by noting the extent or depth of hard-
with the standard.
ening of a standard size and shape test specimen in a
1.3 This specification is expressed in both inch-pound units
standardized quench. In the end-quench test the depth of
and SI units. However, the material will be supplied to
hardening is the distance along the specimen from the
inch-pound units unless the purchase order specifies the “M”
quenched end to a given hardness.
specification designation.
4. Ordering Information
1.4 This international standard was developed in accor-
4.1 Orders for material under this specification should
dance with internationally recognized principles on standard-
include the following information, in proper sequence:
ization established in the Decision on Principles for the
4.1.1 Quantity (weight),
Development of International Standards, Guides and Recom-
4.1.2 Name of material (alloy or carbon-boron steel),
mendations issued by the World Trade Organization Technical
4.1.3 Cross-sectional shape,
Barriers to Trade (TBT) Committee.
4.1.4 Size,
2. Referenced Documents
4.1.5 Length,
2
4.1.6 Grade,
2.1 ASTM Standards:
4.1.7 End-quenched hardenability (see Section 9),
4.1.8 Report of heat analysis, if desired (see Section 7),
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
4.1.9 Special straightness, if required,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
4.1.10 ASTM designation and date of issue, and
A01.15 on Bars.
Current edition approved Nov. 1, 2019. Published November 2019. Originally 4.1.11 End use or special requirements.
approved in 1992. Last previous edition approved in 2016 as A914/A914M – 16.
NOTE 1—A typical ordering description is as follows: 10 000 lb, alloy
DOI: 10.1520/A0914_A0914M-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
the ASTM website. PA 15096, http://www.sae.org.
*A Summary of Changes section appears at the end of this standard
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
1
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...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A914/A914M − 16 A914/A914M − 19
Standard Specification for
Steel Bars Subject to Restricted End-Quench Hardenability
1
Requirements
This standard is issued under the fixed designation A914/A914M; 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*
1.1 This specification covers hot-worked alloy and carbon-boron steels designed to attain restricted depth of hardening in the
end-quench test. These steel compositions are identified by the suffix letter “RH” added to the conventional grade number.
1.2 In general, steels with restricted hardenability (RH steels) will exhibit a hardness range not greater than 5 HRC at the initial
position on the end-quench hardenability bar and not greater than 65 % of the hardness range for standard H-band steels
(Specification A304) in the inflection region. Generally the restricted hardenability band follows the middle of the corresponding
standard H-band. An example of the RH band compared with the H band is given for Grade 4140 in Fig. 1.
1.2.1 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3 This specification is expressed in both inch-pound units and SI units. However, the material will be supplied to inch-pound
units unless the purchase order specifies the “M” specification designation.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
A29/A29M Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
A255 Test Methods for Determining Hardenability of Steel
A304 Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements
E112 Test Methods for Determining Average Grain Size
3
2.2 SAE Standards:
J 406 Methods of Determining Hardenability of Steels
J 1268 Hardenability Bands for Carbon and Alloy H Steels
J 1868 Restricted Hardenability Bands for Selected Alloy Steels
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 hardenability—the relative ability of a steel to harden under heat treatment becomes apparent in the degree to which the
material hardens when quenched at different cooling rates.
3.1.1.1 Discussion—
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.15
on Bars.
Current edition approved Dec. 1, 2016Nov. 1, 2019. Published December 2016November 2019. Originally approved in 1992. Last previous edition approved in 20112016
as A914/A914M - 92A914/A914M – 16.(2011). DOI: 10.1520/A0914_A0914M-16.10.1520/A0914_A0914M-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096, http://www.sae.org.
*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
1
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A914/A914M − 19
Hardenability is measured quantitatively, usually by noting the extent or depth of hardening of a standard size and shape test
specimen in a standardized quench. In the end-quench test the depth of hardening is the distance along the specimen from the
quenched end to a given hardness.
4. Ordering Information
4.1 Orders for material under this specification should include the following information, in proper sequence:
4.1.1 Quantity (weight),
4.1.2 Name of material (alloy or carbon-boron steel),
4.1.3 Cross-sectional shape,
4.1.4 Size,
4.1.5 Length,
4.1.6 Grade,
4.1.7 End-quenched hardenability
...
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