ASTM A921/A921M-93(2016)

Standard Specification for Steel Bars, Microalloy, Hot-Wrought, Special Quality, for Subsequent Hot Forging

ABSTRACT
This specification covers hot-wrought, special quality microalloyed carbon steel bars intended for use as hot forging stock. The bars shall be hot-wrought, as-wrought, unless thermal treatment is necessary to ensure cold shearability. The steel specimens shall be killed and shall conform to the fine grain size requirement. Heat analysis and product analysis shall be performed wherein the specimens shall conform to the required chemical compositions of vanadium, columbium, and molybdenum.
SCOPE
1.1 This specification covers hot-wrought, special quality microalloyed carbon steel bars intended for use as hot forging stock. The bars shall be hot-wrought, as-wrought, unless thermal treatment is necessary to ensure cold shearability.  
1.2 The bars shall be furnished to chemical composition only. Chemical composition is based on standard carbon steel grades modified to include microalloying elements such as columbium (niobium), vanadium, or molybdenum. Desired mechanical properties are developed in the subsequent hot forging and controlled cooling operations.  
1.3 Sections and sizes of bar steel available are covered in Specification A29/A29M.  
1.4 Supplementary Requirements S1 to S6 are provided for use when additional controls or requirements are desired. These shall apply only when specified on the purchase order.  
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text and tables, SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.  
1.6 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.

General Information

• Status: Historical
• Publication Date: 31-Aug-2016
• ICS: 77.140.20 - Stainless steels
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.15 - Bars

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:A921/A921M −93 (Reapproved 2016)
Standard Specification for
Steel Bars, Microalloy, Hot-Wrought, Special Quality, for
1
Subsequent Hot Forging
This standard is issued under the fixed designationA921/A921M; 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 A576 Specification for Steel Bars, Carbon, Hot-Wrought,
Special Quality
1.1 This specification covers hot-wrought, special quality
A788/A788M Specification for Steel Forgings, General Re-
microalloyed carbon steel bars intended for use as hot forging
quirements
stock. The bars shall be hot-wrought, as-wrought, unless
E45 Test Methods for Determining the Inclusion Content of
thermal treatment is necessary to ensure cold shearability.
Steel
1.2 The bars shall be furnished to chemical composition
3. Terminology
only. Chemical composition is based on standard carbon steel
grades modified to include microalloying elements such as
3.1 Definitions of Terms Specific to This Standard:
columbium (niobium), vanadium, or molybdenum. Desired
3.1.1 microalloyed steels—microalloyed steels are carbon
mechanical properties are developed in the subsequent hot
steels to which small quantities of certain elements are added
forging and controlled cooling operations.
in order to enhance mechanical properties. This enhancement
of mechanical properties results from control of the tempera-
1.3 Sections and sizes of bar steel available are covered in
ture and cooling rate during the final hot-working process.
Specification A29/A29M.
1.4 Supplementary Requirements S1 to S6 are provided for
4. Ordering Information
use when additional controls or requirements are desired.
4.1 Orders for material supplied to this specification should
These shall apply only when specified on the purchase order.
include the following, as required, to describe adequately the
1.5 The values stated in either inch-pound units or SI units desired material:
are to be regarded separately as standard. Within the text and
4.1.1 Quantity (weight or number of bars),
tables,SIunitsareshowninbrackets.Thevaluesstatedineach 4.1.2 Name of material (hot-rolled microalloyed steel bars),
system are not exact equivalents; therefore, each system must
4.1.3 Dimensions,
be used independently of the other. Combining values from the
4.1.4 ASTM specification number and date of issue,
two systems may result in nonconformance with the specifi-
4.1.5 Gradedesignationorchemicalcompositionlimits(see
cation.
8.1 – 8.5),
4.1.6 Type (see 7.1) to designate grain refiner,
1.6 Unless the order specifies the applicable “M” specifica-
4.1.7 Additions to the specification and Supplementary
tion designation, the material shall be furnished to the inch-
Requirements, if required, and,
pound units.
4.1.8 End use.
2. Referenced Documents
5. General Requirements
2
2.1 ASTM Standards:
5.1 Material furnished under this specification shall con-
A29/A29M SpecificationforGeneralRequirementsforSteel
form to the applicable requirements of the current edition of
Bars, Carbon and Alloy, Hot-Wrought
Specification A29/A29M, unless otherwise provided in this
specification.
1
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
6. Materials and Manufacture
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.15 on Bars.
6.1 Melting Practice—The steel shall be produced in accor-
Current edition approved Sept. 1, 2016. Published September 2016. Originally
dance with the applicable methods for primary and secondary
approved in 1993. Last previous edition approved in 2011 as A921/
melting outlined in Specification A788/A788M.
A921M - 93(2011). DOI: 10.1520/A0921_A0921M-93R16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.2 The steel shall be killed. Supplementary Requirements
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
S1 through S6 may be invoked upon agreement between
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. producer and purchaser.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
1

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A921/A921M−93 (2016)
TABLE 1 Typical Chemical Compositions of Microalloyed Carbon Steels
NOTE 1—These compositions are identical to those in Specification A576, with the exception of the addition of vanadium.
Chemical Composition Limits, %
Grade Designation C MN PSV
10V40 0.37–0.44 0.60–0.90 0.040 max 0.050 max 0.02–0.20
10V45 0.43–0.50 0.60–0.90 0.040 max 0.050 max 0.02–0.20
11V37 0.32–0.
...

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: A921/A921M − 93 (Reapproved 2011) A921/A921M − 93 (Reapproved 2016)
Standard Specification for
Steel Bars, Microalloy, Hot-Wrought, Special Quality, for
1
Subsequent Hot Forging
This standard is issued under the fixed designation A921/A921M; 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-wrought, special quality microalloyed carbon steel bars intended for use as hot forging stock.
The bars shall be hot-wrought, as-wrought, unless thermal treatment is necessary to ensure cold shearability.
1.2 The bars shall be furnished to chemical composition only. Chemical composition is based on standard carbon steel grades
modified to include microalloying elements such as columbium (niobium), vanadium, or molybdenum. Desired mechanical
properties are developed in the subsequent hot forging and controlled cooling operations.
1.3 Sections and sizes of bar steel available are covered in Specification A29/A29M.
1.4 Supplementary requirementsRequirements S1 to S6 are provided for use when additional controls or requirements are
desired. These shall apply only when specified on the purchase order.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text and tables,
SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used
independently of the other. Combining values from the two systems may result in nonconformance with the specification.
1.6 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound
units.
2. Referenced Documents
2
2.1 ASTM Standards:
A29/A29M Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
A576 Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality
A788/A788M Specification for Steel Forgings, General Requirements
E45 Test Methods for Determining the Inclusion Content of Steel
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 microalloyed steels—microalloyed steels are carbon steels to which small quantities of certain elements are added in order
to enhance mechanical properties. This enhancement of mechanical properties results from control of the temperature and cooling
rate during the final hot-working process.
4. Ordering Information
4.1 Orders for material supplied to this specification should include the following, as required, to describe adequately the desired
material:
4.1.1 Quantity (weight or number of bars),
4.1.2 Name of material (hot-rolled microalloyed steel bars),
4.1.3 Dimensions,
4.1.4 ASTM specification number and date of issue,
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 April 1, 2011Sept. 1, 2016. Published June 2011September 2016. Originally approved in 1993. Last previous edition approved in 20052011 as
A921/A921M - 93(2005).(2011). DOI: 10.1520/A0921_A0921M-93R11.10.1520/A0921_A0921M-93R16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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A921/A921M − 93 (2016)
4.1.5 Grade designation or chemical composition limits (see 8.1 – 8.5),
4.1.6 Type (see 7.1) to designate grain refiner,
4.1.7 Additions to the specification and Supplementary Requirements, if required, and,
4.1.8 End use.
5. General Requirements
5.1 Material furnished under this specification shall conform to the applicable requirements of the current edition of
Specification A29/A29M, unless otherwise provided in this specification.
6. Materials and Manufacture
6.1 Melting Practice—The steel shall be produced in accordance with the applicable methods for primary and secondary melting
outlined in Specification A788/A788M.
6.2 The steel shall be killed. Supplementary Requirements S1 through S6 may be invoked upon agreement b
...