ASTM A304-20

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: A304 −20
Standard Specification for
Carbon and Alloy Steel Bars Subject to End-Quench
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Hardenability Requirements
This standard is issued under the fixed designation A304; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* E527 Practice for Numbering Metals and Alloys in the
Unified Numbering System (UNS)
1.1 This specification covers hot-worked alloy, carbon, and
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2.2 Society of Automotive Engineers (SAE) Standard:
carbon-boron steels in a variety of compositions and sizes,
J 1086 Numbering Metals and Alloys
which may attain specified depth of hardening in the end
quench test. These steel compositions are identified by the
3. Terminology
suffix letter “H” added to the conventional grade number.
3.1 Definitions of Terms Specific to This Standard:
1.2 This specification provides for analyses other than those
3.1.1 hardenability—the relative ability of a steel to harden
listed under Tables 1 and 2. Special hardenability limits are
under heat treatment becomes apparent in the degree to which
also permissible when approved by the purchaser and manu-
the material hardens when quenched at different cooling rates.
facturer.
It is measured quantitatively, usually by noting the extent or
depth of hardening of a standard size and shape test specimen
1.3 The values stated in inch-pound units are to be regarded
in a standardized quench. In the “end-quench” test the “depth
as standard. No other units of measurement are included in this
of hardening” is the distance along the specimen from the
standard.
quenched end to a given hardness.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Ordering Information
ization established in the Decision on Principles for the
4.1 Orders for material under this specification should
Development of International Standards, Guides and Recom-
include the following information, in proper sequence:
mendations issued by the World Trade Organization Technical
4.1.1 Quantity (weight);
Barriers to Trade (TBT) Committee.
4.1.2 Name of material (alloy, carbon, or carbon-boron
steel);
2. Referenced Documents
4.1.3 Cross-sectional shape;
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2.1 ASTM Standards:
4.1.4 Size;
A29/A29M SpecificationforGeneralRequirementsforSteel
4.1.5 Length;
Bars, Carbon and Alloy, Hot-Wrought
4.1.6 Grade;
A108 Specification for Steel Bar, Carbon and Alloy, Cold-
4.1.7 End-quenched hardenability (see Section 9);
Finished
4.1.8 Report of heat analysis, if desired (see Section 7);
A255 Test Methods for Determining Hardenability of Steel
4.1.9 Special straightness, if required;
E112 Test Methods for Determining Average Grain Size
4.1.10 ASTM designation and date of issue;
4.1.11 End use or special requirements; and
4.1.12 Leaded steel, when required.
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This specification is under the jurisdiction ofASTM Committee A01 on Steel,
NOTE 1—A typical ordering description is as follows: 10 000 lb, alloy
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
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bars, round, 4.0 in. dia by 10 ft, Grade 1340H, J 40⁄56 = ⁄16 in., heat
A01.15 on Bars.
analysis required, ASTM A304, dated ________, worm gear.
Current edition approved July 1, 2020. Published July 2020. Originally approved
in 1947. Last previous edition approved in 2016 as A304 – 16. DOI: 10.1520/
4.2 The purchaser shall specify the desired grade, including
A0304-20.
the suffix letter “H,” in accordance with Table 1 or Table 2.
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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
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Standards volume information, refer to the standard’ 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, PA 19428-2959. United States
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A304 − 20
A
TABLE 1 Chemical Requirements of Alloy H Steels
NOTE 1—Phosphorus and sulfur designated by the prefix letter “E” is 0.025 %, max.
NOTE 2—Small quantities of certain elements are present in alloy steels that are not specified or required. These elements are considered as incidental
and may be present to t
...