ASTM A231/A231M-18

Standard Specification for Chromium-Vanadium Alloy Steel Spring Wire

ABSTRACT
This specification covers round chromium-vanadium alloy steel spring wires having properties and quality intended for the manufacture of springs used at moderately elevated temperatures. Wires shall either be in the annealed and cold-drawn or oil-tempered condition as specified by the purchaser. The steel may either be ingot cast or strand cast, and the finished wire shall be free from detrimental pipe and undue segregation. Specimens shall undergo cast or heat analysis, and shall conform to required chemical compositions for carbon, manganese, phosphorus, sulfur, silicon, chromium, and vanadium. Wrap tests shall also be performed wherein mechanical properties shall be assessed for tensile strength requirements. Metallurgical properties, such as the surface condition and decarburization, shall be inspected as well. For all test procedures, one specimen shall be taken for each ten coils, or fraction thereof, in a lot. Each cast or heat in a given lot shall be tested.
SCOPE
1.1 This specification covers round and shaped chromium-vanadium alloy steel spring wire having properties and quality intended for the manufacture of springs used at moderately elevated temperatures. This wire shall be either in the annealed and cold-drawn or oil-tempered condition as specified by the purchaser.  
1.2 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.  
1.2.1 Within the text, the inch-pound units are shown in brackets.  
1.3 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.

General Information

• Status: Published
• Publication Date: 31-Aug-2018
• ICS: 77.140.25 - Spring steels
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.03 - Steel Rod and Wire

Relations

• Replaces: ASTM A231/A231M-15 - Standard Specification for Chromium-Vanadium Alloy Steel Spring Wire
• Effective Date: 01-Sep-2018
• Refers: ASTM A370-24 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Mar-2024
• Refers: ASTM A941-24 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Mar-2024
• Refers: ASTM E8/E8M-24 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM A700-14(2019) - Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
• Effective Date: 01-Nov-2019
• Refers: ASTM A370-19 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jul-2019
• Refers: ASTM A370-17a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2017
• Refers: ASTM A941-17 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Sep-2017
• Refers: ASTM A370-17 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jan-2017
• Refers: ASTM E8/E8M-16 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 15-Jul-2016
• Refers: ASTM A370-15 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Nov-2015
• Refers: ASTM A941-15 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Nov-2015
• Refers: ASTM E8/E8M-15 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Feb-2015
• Refers: ASTM A700-14 - Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
• Effective Date: 01-Nov-2014
• Refers: ASTM A370-14 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-May-2014

Overview

ASTM A231/A231M-18: Standard Specification for Chromium-Vanadium Alloy Steel Spring Wire is an internationally recognized standard developed by ASTM International. This specification details the requirements for round and shaped chromium-vanadium alloy steel wire used primarily in the manufacture of springs intended for service at moderately elevated temperatures. The wire covered by this standard is available in either an annealed and cold-drawn or oil-tempered condition, as specified by the purchaser. The standard ensures that the steel spring wire meets stringent requirements for chemical composition, mechanical properties, surface quality, and dimensional accuracy, making it highly suitable for demanding spring applications in various industries.

Key Topics

• Material and Manufacturing: Specifies that the steel used may be produced by any commercially accepted process, with options for ingot or strand casting. The finished wire must be free from detrimental pipe and segregation.
• Chemical Composition: The standard outlines strict requirements for essential elements such as carbon, manganese, phosphorus, sulfur, silicon, chromium, and vanadium, ensuring optimal performance.
• Mechanical Properties: Covers tensile strength and reduction of area requirements tailored by diameter and condition of the wire, ensuring the wire's performance in spring applications.
• Product Types: Applies to both round and shaped (non-circular cross-section) wire, with explicit definitions for shape factor and equivalent round diameter.
• Testing and Inspection: Details procedures for heat analysis, mechanical testing, wrap and decarburization tests, and surface inspections. Specifies frequency, location, and methods for representative sampling.
• Dimensional Tolerances: Clearly defines permissible variations for wire diameter and out-of-roundness, supporting high-precision applications.
• Workmanship and Appearance: Sets minimum standards for coil integrity, absence of surface defects, and identity marking for shipment.
• Documentation and Certification: Allows for required certification to ensure that wire is manufactured and tested in accordance with ASTM A231/A231M-18.

Applications

Chromium-vanadium alloy steel spring wire produced to ASTM A231/A231M-18 is utilized in manufacturing springs that are exposed to moderately elevated temperatures and require consistent mechanical performance. Key application areas include:

• Automotive: Suspension, valve, and transmission springs.
• Industrial Machinery: Springs subject to moderate heat and dynamic loading, such as in actuators and clutches.
• Aerospace: Components needing reliable spring performance in elevated temperature environments.
• General Engineering: Tension, compression, and torsion springs used in diverse equipment and machinery.

Manufacturers, suppliers, and purchasers rely on this standard for quality assurance, ensuring that the spring wire meets necessary mechanical and chemical requirements for reliable performance and durability.

Related Standards

Several related ASTM standards complement or are referenced within ASTM A231/A231M-18:

• ASTM A370: Test Methods and Definitions for Mechanical Testing of Steel Products
• ASTM A510/A510M: Specification for General Requirements for Wire Rods and Coarse Round Wire, Carbon Steel, and Alloy Steel
• ASTM A700: Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
• ASTM A751: Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
• ASTM A941: Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• ASTM E8/E8M: Test Methods for Tension Testing of Metallic Materials
• ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

Summary

ASTM A231/A231M-18 establishes critical guidelines for chromium-vanadium alloy steel spring wire production, ensuring high-quality springs capable of performing at moderately elevated temperatures. Compliance with this standard guarantees consistency in mechanical properties, chemical composition, and dimensional accuracy, supporting reliable spring performance in a wide range of demanding applications.

Standards Content (Sample)

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:A231/A231M −18
Standard Specification for
Chromium-Vanadium Alloy Steel Spring Wire
This standard is issued under the fixed designationA231/A231M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber 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* cal Analysis of Steel Products
A941TerminologyRelatingtoSteel,StainlessSteel,Related
1.1 This specification covers round and shaped chromium-
Alloys, and Ferroalloys
vanadium alloy steel spring wire having properties and quality
E8/E8MTest Methods for Tension Testing of Metallic Ma-
intended for the manufacture of springs used at moderately
terials
elevatedtemperatures.Thiswireshallbeeitherintheannealed
E29Practice for Using Significant Digits in Test Data to
and cold-drawn or oil-tempered condition as specified by the
Determine Conformance with Specifications
purchaser.
1.2 The values stated in either SI units or inch-pound units
3. Terminology
are to be regarded separately as standard. The values stated in
3.1 Definitions:
each system may not be exact equivalents; therefore, each
3.1.1 For definitions of terms used in this specification, see
system shall be used independently of the other. Combining
Terminology A941.
values from the two systems may result in non-conformance
3.2 Definitions of Terms Specific to This Standard:
with the standard.
3.2.1 equivalent round diameter, n—diameter of a round
1.2.1 Within the text, the inch-pound units are shown in
wire having equivalent cross sectional area to a given shaped
brackets.
wire.
1.3 This international standard was developed in accor-
3.2.2 round wire, n—wire having a circular cross section.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 3.2.3 shape factor, n—this value is used to obtain cross
sectional area for shaped wires when multiplied by measured
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical width and thickness.
Barriers to Trade (TBT) Committee.
3.2.4 shaped wire, n—wire having a non-circular cross
section.
2. Referenced Documents
2.1 ASTM Standards:
4. Ordering Information
A370Test Methods and Definitions for Mechanical Testing
4.1 It shall be the responsibility of the purchaser to specify
of Steel Products
all requirements that are necessary for material under this
A510/A510MSpecification for General Requirements for
specification. Such requirements may include, but are not
Wire Rods and Coarse Round Wire, Carbon Steel, and
limited to, the following:
Alloy Steel
4.1.1 Quantity (mass),
A700Guide for Packaging, Marking, and Loading Methods
4.1.2 Name of material (chromium-vanadium alloy steel
for Steel Products for Shipment
wire),
A751Test Methods, Practices, and Terminology for Chemi-
4.1.3 Wire diameter (Table 1 and Section 9), and
4.1.4 ASTM designation and date of issue.
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
4.2 Thepurchasershallhavetheoptiontospecifyadditional
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee
requirements, including but not limited to:
A01.03 on Steel Rod and Wire.
4.2.1 Requirements for certifications, heat analysis or test
Current edition approved Sept. 1, 2018. Published September. Originally
reports (6.2 and Section 14),
approved in 1939. Last previous edition approved in 2015 as A231/A231M–15.
DOI: 10.1520/A0231_A0231M-18.
4.2.2 Special packing, marking, and loading requirements
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
(Section 15), and
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.2.3 Other special requirements, if any.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
*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
A231/A231M−18
A
TABLE 1 Tensile Requirements
5. Materials and Manufacture
SI Units 5.1 The steel may be made by any commercially accepted
steel–making process. The steel may be either ingot cast or
Reduction of Areas,
B
Diameter, mm MPa, min MPa, max
C,D strand cast.
min, %
5.2 The finished wire shall be free from detrimental pipe
0.50 2060 2260 . . .
and undue segregation.
0.55 2050 2240 . . .
0.60 2030 2220 . . .
6. Chemical Composition
0.65 2010 2200 . . .
0.70 2000 2160 . . .
6.1 The steel shall conform to the requirements of Grade
0.80 1980 2140 . . .
6150 for chemical composition specified in Table 2.
0.90 1960 2120 . . .
1.00 1940 2100 . . .
6.2 Heat Analysis—Each heat of steel shall be analyzed to
1.10 1920 2080 . . .
1.20 1900 2060 . . . determine the percentage of elements prescribed in Table 2.
1.40 1860 2020 . . .
This analysis shall be made from a test specimen preferably
1.60 1820 1980 . . .
takenduringthepouringoftheheat.Whenrequested,thisshall
1.80 1800 1960 . . .
2.00 1780 1930 . . . be reported to the purchaser and shall conform to the require-
2.20 1750 1900 . . .
ments of Table 2.
2.50 1720 1860 45
2.80 1680 1830 45
6.3 Product Analysis—An analysis may be made by the
3.00 1660 1800 45
purchaser from finished wire representing each heat of steel.
3.50 1620 1760 45
The chemical composition thus determined, as to elements
4.00 1580 1720 40
4.50 1560 1680 40
required or restricted, shall conform to the product analysis
5.00 1520 1640 40
requirements specified in Table 4 of Specification A510/
5.50 1480 1620 40
A510M.
6.00 1460 1600 40
6.50 1440 1580 40
6.4 For referee purposes, Test Methods, Practices, and
7.00 1420 1560 40
8.00 1400 1540 40 Terminology A751 shall be used.
9.00 1380 1520 40
10.00 1360 1500 40
7. Mechanical Properties
11.00 1340 1480 40
12.00 1320 1460 40
7.1 Annealed and Cold Drawn—When purchased in the
annealed and cold-drawn condition, the wire shall have been
Inch-Pound Units
given a sufficient amount of cold working to meet the purchas-
Reduction of Area, min
B
Diameter, in. ksi, min. ksi, max
C,D
%
er’scoilingrequirementsandshallbeinasuitableconditionto
0.020 300 325 . . .
respond properly to heat treatment. In special cases the
0.032 290 315 . . .
hardness, or tensile strength, if desired, shall be stated in the
0.041 280 305 . . .
0.054 270 295 . . .
purchase order.
0.062 265 290 . . .
0.080 255 275 . . . 7.2 Oil Tempered—When purchased in the oil-tempered
0.105 245 265 45
condition, the tensile strength and minimum percent reduction
0.135 235 255 45
of area shall conform to the requirements as shown in Table 1.
0.162 225 245 40
Tensilestrengthofshapedandflatrolledwiresshallconformto
0.192 220 240 40
0.244 210 230 40
this table based on the conversion to equivalent round dimen-
0.283 205 225 40
sions. Percent reduction of area is not applicable to shaped and
0.312 203 223 40
0.375 200 220 40 flat rolled wires.
0.438 195 215 40
7.2.1 Number of Tests—Onetestspecimenshallbetakenfor
0.500 190 210 40
each ten coils, or fraction thereof, in a lot. Each heat in a given
A
Tensile strength values for intermediate diameters may be interpolated.
lot shall be tested.
B
Preferred sizes.
C
The reduction of area test is not applicable to wire diameters under 2.34 mm
[0.092 in.] in diameter. For intermediate wire diameters, the reduction of area
TABLE 2 Chemical Requirements
requirement shall be that of the next larger wire.
D
Element Analysis, %
“. . .” indicates that there is no requirement.
Carbon 0.48–0.53
Manganese 0.70–0.90
Phosphorus 0.035 max
NOTE 1—A typical ordering description is as follows: 20000 kg
Sulfur 0.040 max
oil-tempered chromium-vanadium alloy steel wire, size 6.00 mm in
Silicon 0.15–0.35
150-kg coils to ASTM A231/A231M dated_______ , or for inch-pound
Chromium 0.80–1.10
units, 40000 lb oil-tempered chromium-vanadium alloy steel spring wire,
Vanadium 0.15 min
size 0.250 in. in 350-lb coils to ASTM A231/A231M dated_______.
A231/A231M−18
7.2.2 Location of Tests—It shall be permissible to take test 8.2 Decarburization:
specimens from either end of the coil. 8.2.1 The depth of complete decarburization (free ferrite)
7.2.3 Test Method—The tension test shall be made in shall not exceed 0.75% of the equivalent round wire diameter.
accordance with Test Methods and Definitions A370. For The total affected depth (free ferrite plus partial decarburiza-
shaped wires, cross sectional area shall be calculated either by tion) shall not exceed 2.0% of the equivalent round wire
using the procedure in Test Methods E8/E8M for uniform but diameter on all sizes of wire.
nonsymmetrical cross-sections, or by measuring width and 8.2.2 Test Method—Decarburization shall be determined by
thickness and multiplying by a shape factor. Reduction of area etching a suitably polished transverse section of the wire with
for shaped wires shall be calculated by using this shape factor. nital. The entire periphery to be examined shall be in a single
Measurethemaximumandminimumdimensiononthenecked plane with no edge rounding.
down section and multiply by the shape factor to estimate the 8.2.3 The entire periphery shall be examined at a magnifi-
cross sectional area for use in the standa
...

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: A231/A231M − 15 A231/A231M − 18
Standard Specification for
Chromium-Vanadium Alloy Steel Spring Wire
This standard is issued under the fixed designation A231/A231M; 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*
1.1 This specification covers round and shaped chromium-vanadium alloy steel spring wire having properties and quality
intended for the manufacture of springs used at moderately elevated temperatures. This wire shall be either in the annealed and
cold-drawn or oil-tempered condition as specified by the purchaser.
1.2 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.
1.2.1 Within the text, the inch-pound units are shown in brackets.
1.3 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
2.1 ASTM Standards:
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A510/A510M Specification for General Requirements for Wire Rods and Coarse Round Wire, Carbon Steel, and Alloy Steel
A700 Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
E8/E8M Test Methods for Tension Testing of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this specification, see Terminology A941.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 equivalent round diameter, n—diameter of a round wire having equivalent cross sectional area to a given shaped wire.
3.2.2 round wire, n—wire having a circular cross section.
3.2.3 shape factor, n—this value is used to obtain cross sectional area for shaped wires when multiplied by measured width and
thickness.
3.2.4 shaped wire, n—wire having a non-circular cross section.
4. Ordering Information
4.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for material under this
specification. Such requirements may include, but are not limited to, the following:
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.03
on Steel Rod and Wire.
Current edition approved Nov. 1, 2015Sept. 1, 2018. Published November 2015September. Originally approved in 1939. Last previous edition approved in 20102015 as
A231/A231M – 10.A231/A231M – 15. DOI: 10.1520/A0231_A0231M-15.10.1520/A0231_A0231M-18.
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.
*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
A231/A231M − 18
4.1.1 Quantity (mass),
4.1.2 Name of material (chromium-vanadium alloy steel wire),
4.1.3 Wire diameter (Table 1 and Section 9), and
4.1.4 ASTM designation and date of issue.
4.2 It The purchaser shall be the responsibility of the purchaser to specify all requirements that are necessary for material under
this specification. Such requirements may include, but are not limited to, the following:have the option to specify additional
requirements, including but not limited to:
3.1.1 Quantity (mass),
3.1.2 Name of material (chromium-vanadium alloy steel wire),
4.2.1 Wire diameter Requirements for certifications, heat analysis or test reports (Table 16.2 and Section 814),
3.1.4 Packaging (Section 14),
3.1.5 Heat analysis report (if requested) (5.2),
4.2.2 Certification or test report, or both, if specified Special packing, marking, and loading requirements (Section 1315), and
4.2.3 ASTM designation and date of Other special requirements, if any.
issue.
NOTE 1—A typical ordering description is as follows: 20 000 kg oil-tempered chromium-vanadium alloy steel wire, size 6.00 mm in 150-kg coils to
ASTM A231/A231M dated_______ , or for inch-pound units, 40 000 lb oil-tempered chromium-vanadium alloy steel spring wire, size 0.250 in. in 350-lb
coils to ASTM A231/A231M dated_______.
NOTE 1—A typical ordering description is as follows: 20 000 kg oil-tempered chromium-vanadium alloy steel wire, size 6.00 mm in 150-kg coils to
ASTM A231/A231M dated_______ , or for inch-pound units, 40 000 lb oil-tempered chromium-vanadium alloy steel spring wire, size 0.250 in. in 350-lb
coils to ASTM A231/A231M dated_______.
5. Materials and Manufacture
5.1 The steel may be made by any commercially accepted steel–making process. The steel may be either ingot cast or strand
cast.
5.2 The finished wire shall be free from detrimental pipe and undue segregation.
6. Chemical Composition
6.1 The steel shall conform to the requirements of Grade 6150 for chemical composition specified in Table 2.
6.2 Heat Analysis—Each heat of steel shall be analyzed by the manufacturer to determine the percentage of elements prescribed
in Table 2. This analysis shall be made from a test specimen preferably taken during the pouring of the heat. When requested, this
shall be reported to the purchaser and shall conform to the requirements of Table 2.
6.3 Product Analysis—An analysis may be made by the purchaser from finished wire representing each heat of steel. The
chemical composition thus determined, as to elements required or restricted, shall conform to the product analysis requirements
specified in Table 4 of Specification A510/A510M.
6.4 For referee purposes, Test Methods, Practices, and Terminology A751 shall be used.
7. Mechanical Properties
7.1 Annealed and Cold Drawn—When purchased in the annealed and cold-drawn condition, the wire shall have been given a
sufficient amount of cold working to meet the purchaser’s coiling requirements and shall be in a suitable condition to respond
properly to heat treatment. In special cases the hardness, or tensile strength, if desired, shall be stated in the purchase order.
7.2 Oil Tempered—When purchased in the oil-tempered condition, the tensile strength and minimum percent reduction of area,
sizes 2.50 mm [0.105 in.] and coarser, of the wire area shall conform to the requirements as shown in Table 1. Tensile strength
of shaped and flat rolled wires shall conform to this table based on the conversion to equivalent round dimensions. Percent
reduction of area is not applicable to shaped and flat rolled wires.
NOTE 2—Equivalent Round Definition: The cross-sectional area of non-round wires converted to the round wire diameter.
7.2.1 Number of Tests—One test specimen shall be taken for each ten coils, or fraction thereof, in a lot. Each heat in a given
lot shall be tested.
7.2.2 Location of Tests—Test specimens It shall be taken permissible to take test specimens from either end of the coil.
7.2.3 Test Method—The tension test shall be made in accordance with Test Methods and Definitions A370. For shaped wires,
cross sectional area shall be calculated either by using the procedure in Test Methods E8/E8M for uniform but nonsymmetrical
cross-sections, or by measuring width and thickness and multiplying by a shape factor. Reduction of area for shaped wires shall
be calculated by using this shape factor. Measure the maximum and minimum dimension on the necked down section and multiply
by the shape factor to estimate the cross sectional area for use in the standard reduction of area calculation.
A231/A231M − 18
A
TABLE 1 Tensile Requirements
SI Units
SI UnitsMPa, Reduction of Areas,
B
Diameter, mm MPa, max
C,D
min min, %
MPa, min MPa, max
C
0.50 2060 2260
0.50 2060 2260 . . .
C
0.55 2050 2240
0.55 2050 2240 . . .
C
0.60 2030 2220
0.60 2030 2220 . . .
C
0.65 2010 2200
0.65 2010 2200 . . .
C
0.70 2000 2160
0.70 2000 2160 . . .
C
0.80 1980 2140
0.80 1980 2140 . . .
C
0.90 1960 2120
0.90 1960 2120 . . .
C
1.00 1940 2100
1.00 1940 2100 . . .
C
1.10 1920 2080
1.10 1920 2080 . . .
C
1.20 1900 2060
1.20 1900 2060 . . .
C
1.40 1860 2020
1.40 1860 2020 . . .
C
1.60 1820 1980
1.60 1820 1980 . . .
C
1.80 1800 1960
1.80 1800 1960 . . .
C
2.00 1780 1930
2.00 1780 1930 . . .
C
2.20 1750 1900
2.20 1750 1900 . . .
2.50 1720 1860 45
2.80 1680 1830 45
3.00 1660 1800 45
3.50 1620 1760 45
4.00 1580 1720 40
4.50 1560 1680 40
5.00 1520 1640 40
5.50 1480 1620 40
6.00 1460 1600 40
6.50 1440 1580 40
7.00 1420 1560 40
8.00 1400 1540 40
9.00 1380 1520 40
10.00 1360 1500 40
11.00 1340 1480 40
12.00 1320 1460 40
Inch-Pound Units
Inch-Pound Reduction of
B
Diameter, in.
Units Area, min %
Reduction of Area, min
B
Diameter, in. ksi, min. ksi, max
C,D
%
ksi, min. ksi, max
C
0.020 300 325
0.020 300 325 . . .
C
0.032 290 315
0.032 290 315 . . .
C
0.041 280 305
0.041 280 305 . . .
C
0.054 270 295
0.054 270 295 . . .
C
0.062 265 290
0.062 265 290 . . .
C
0.080 255 275
0.080 255 275 . . .
0.105 245 265 45
0.135 235 255 45
0.162 225 245 40
0.192 220 240 40
A231/A231M − 18
SI Units
SI UnitsMPa, Reduction of Areas,
B
Diameter, mm MPa, max
C,D
min min, %
MPa, min MPa, max
0.244 210 230 40
0.283 205 225 40
0.312 203 223 40
0.375 200 220 40
0.438 195 215 40
0.500 190 210 40
A
Tensile strength values for intermediate diameters may be interpolated.
B
Preferred sizes. For a complete list, refer to ANSI B 32.4M.
C
The reduction of area test is not applicable to wire diameters under 2.34 mm
[0.092 in.] in diameter. For intermediate wire diameters, the reduction of area
requirement shall be that of the next larger wire.
D
“. . .” indicates that there is no requirement.
TABLE 2 Chemical Requirements
Element Analysis, %
Element Analysis,
...