ASTM E18-20
(Test Method)Standard Test Methods for Rockwell Hardness of Metallic Materials
Standard Test Methods for Rockwell Hardness of Metallic Materials
SIGNIFICANCE AND USE
4.1 The Rockwell hardness test is an empirical indentation hardness test that can provide useful information about metallic materials. This information may correlate to tensile strength, wear resistance, ductility, and other physical characteristics of metallic materials, and may be useful in quality control and selection of materials.
4.2 Rockwell hardness tests are considered satisfactory for acceptance testing of commercial shipments, and have been used extensively in industry for this purpose.
4.3 Rockwell hardness testing at a specific location on a part may not represent the physical characteristics of the whole part or end product.
4.4 Adherence to this standard test method provides traceability to national Rockwell hardness standards except as stated otherwise.
SCOPE
1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests.
1.2 This test method includes requirements for the use of portable Rockwell hardness testing machines that measure Rockwell hardness by the Rockwell hardness test principle and can meet all the requirements of this test method, including the direct and indirect verifications of the testing machine. Portable Rockwell hardness testing machines that cannot meet the direct verification requirements and can only be verified by indirect verification requirements are covered in Test Method E110.
1.3 This standard includes additional requirements in the following annexes:
Verification of Rockwell Hardness Testing Machines
Annex A1
Rockwell Hardness Standardizing Machines
Annex A2
Standardization of Rockwell Indenters
Annex A3
Standardization of Rockwell Hardness Test Blocks
Annex A4
Guidelines for Determining the Minimum Thickness of a
Test Piece
Annex A5
Hardness Value Corrections When Testing on Convex
Cylindrical Surfaces
Annex A6
1.4 This standard includes nonmandatory information in the following appendixes that relates to the Rockwell hardness test.
List of ASTM Standards Giving Hardness Values Corresponding
to Tensile Strength
Appendix X1
Examples of Procedures for Determining Rockwell
Hardness Uncertainty
Appendix X2
1.5 Units—At the time the Rockwell hardness test was developed, the force levels were specified in units of kilograms-force (kgf) and the indenter ball diameters were specified in units of inches (in.). This standard specifies the units of force and length in the International System of Units (SI); that is, force in Newtons (N) and length in millimeters (mm). However, because of the historical precedent and continued common usage, force values in kgf units and ball diameters in inch units are provided for information and much of the discussion in this standard refers to these units.
1.6 The test principles, testing procedures, and verification procedures are essentially identical for both the Rockwell and Rockwell superficial hardness tests. The significant differences between the two tests are that the test forces are smaller for the Rockwell superficial test than for the Rockwell test. The same type and size indenters may be used for either test, depending on the scale being employed. Accordingly, throughout this standard, the term Rockwell will imply both Rockwell and Rockwell superficial unless stated otherwise.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized p...
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Designation: E18 − 20 An American National Standard
Standard Test Methods for
1,2
Rockwell Hardness of Metallic Materials
ThisstandardisissuedunderthefixeddesignationE18;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
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* kilograms-force (kgf) and the indenter ball diameters were
specified in units of inches (in.). This standard specifies the
1.1 These test methods cover the determination of the
units of force and length in the International System of Units
Rockwell hardness and the Rockwell superficial hardness of
(SI); that is, force in Newtons (N) and length in millimeters
metallic materials by the Rockwell indentation hardness prin-
(mm). However, because of the historical precedent and
ciple. This standard provides the requirements for Rockwell
continued common usage, force values in kgf units and ball
hardness machines and the procedures for performing Rock-
diameters in inch units are provided for information and much
well hardness tests.
of the discussion in this standard refers to these units.
1.2 This test method includes requirements for the use of
1.6 The test principles, testing procedures, and verification
portable Rockwell hardness testing machines that measure
procedures are essentially identical for both the Rockwell and
RockwellhardnessbytheRockwellhardnesstestprincipleand
Rockwell superficial hardness tests.The significant differences
canmeetalltherequirementsofthistestmethod,includingthe
betweenthetwotestsarethatthetestforcesaresmallerforthe
directandindirectverificationsofthetestingmachine.Portable
Rockwell superficial test than for the Rockwell test. The same
Rockwellhardnesstestingmachinesthatcannotmeetthedirect
type and size indenters may be used for either test, depending
verification requirements and can only be verified by indirect
on the scale being employed. Accordingly, throughout this
verification requirements are covered in Test Method E110.
standard, the term Rockwell will imply both Rockwell and
1.3 This standard includes additional requirements in the
Rockwell superficial unless stated otherwise.
following annexes:
1.7 This standard does not purport to address all of the
Verification of Rockwell Hardness Testing Machines Annex A1
safety concerns, if any, associated with its use. It is the
Rockwell Hardness Standardizing Machines Annex A2
responsibility of the user of this standard to establish appro-
Standardization of Rockwell Indenters Annex A3
Standardization of Rockwell Hardness Test Blocks Annex A4
priate safety, health, and environmental practices and deter-
Guidelines for Determining the Minimum Thickness of a Annex A5
mine the applicability of regulatory limitations prior to use.
Test Piece
1.8 This international standard was developed in accor-
Hardness Value Corrections When Testing on Convex Annex A6
Cylindrical Surfaces
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
1.4 Thisstandardincludesnonmandatoryinformationinthe
following appendixes that relates to the Rockwell hardness Development of International Standards, Guides and Recom-
test. mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
List of ASTM Standards Giving Hardness Values Appendix X1
Corresponding
to Tensile Strength
2. Referenced Documents
Examples of Procedures for Determining Rockwell Appendix X2
3
Hardness Uncertainty
2.1 ASTM Standards:
A370Test Methods and Definitions for Mechanical Testing
1.5 Units—At the time the Rockwell hardness test was
of Steel Products
developed, the force levels were specified in units of
A623Specification for Tin Mill Products, General Require-
ments
1
These test methods are under the jurisdiction of ASTM Committee E28 on A623MSpecification for Tin Mill Products, General Re-
Mechanical Testing and are the direct responsibility of Subcommittee E28.06 on
quirements [Metric]
Indentation Hardness Testing.
Current edition approved Feb. 1, 2020. Published March 2020. Originally
approved in 1932. Last previous edition approved in 2019 as E18–19. DOI:
3
10.1520/E0018-20 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2
In this test method, the term Rockwell refers to an internationally recognized contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
type of indentation hardness test as defined in Section 3, and not to the hardness Standards volume information, refer to the standard’s Document Summary page on
testing equipment of a particular manufacturer. the ASTM w
...
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: E18 − 19 E18 − 20 An American National Standard
Standard Test Methods for
1,2
Rockwell Hardness of Metallic Materials
This standard is issued under the fixed designation E18; 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 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic
materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines
and the procedures for performing Rockwell hardness tests.
1.2 This test method includes requirements for the use of portable Rockwell hardness testing machines that measure Rockwell
hardness by the Rockwell hardness test principle and can meet all the requirements of this test method, including the direct and
indirect verifications of the testing machine. Portable Rockwell hardness testing machines that cannot meet the direct verification
requirements and can only be verified by indirect verification requirements are covered in Test Method E110.
1.3 This standard includes additional requirements in the following annexes:
Verification of Rockwell Hardness Testing Machines Annex A1
Rockwell Hardness Standardizing Machines Annex A2
Standardization of Rockwell Indenters Annex A3
Standardization of Rockwell Hardness Test Blocks Annex A4
Guidelines for Determining the Minimum Thickness of a Annex A5
Test Piece
Hardness Value Corrections When Testing on Convex Annex A6
Cylindrical Surfaces
1.4 This standard includes nonmandatory information in the following appendixes that relates to the Rockwell hardness test.
List of ASTM Standards Giving Hardness Values Appendix X1
Corresponding
to Tensile Strength
Examples of Procedures for Determining Rockwell Appendix X2
Hardness Uncertainty
1.5 Units—At the time the Rockwell hardness test was developed, the force levels were specified in units of kilograms-force
(kgf) and the indenter ball diameters were specified in units of inches (in.). This standard specifies the units of force and length
in the International System of Units (SI); that is, force in Newtons (N) and length in millimeters (mm). However, because of the
historical precedent and continued common usage, force values in kgf units and ball diameters in inch units are provided for
information and much of the discussion in this standard refers to these units.
1.6 The test principles, testing procedures, and verification procedures are essentially identical for both the Rockwell and
Rockwell superficial hardness tests. The significant differences between the two tests are that the test forces are smaller for the
Rockwell superficial test than for the Rockwell test. The same type and size indenters may be used for either test, depending on
the scale being employed. Accordingly, throughout this standard, the term Rockwell will imply both Rockwell and Rockwell
superficial unless stated otherwise.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.8 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.
1
These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and are the direct responsibility of Subcommittee E28.06 on Indentation
Hardness Testing.
Current edition approved Jan. 1, 2019Feb. 1, 2020. Published February 2019March 2020. Originally approved in 1932. Last previous edition approved in 20182019 as
E18 – 18a.E18 – 19. DOI: 10.1520/E0018-1910.1520/E0018-20
2
In this test method, the term Rockwell refers to an internationally recognized type of indentation hardness test as defined in Section 3, and not to the hardness testing
equipment of a particular manufacturer.
*A Summary of Changes section appears at the end of this standard
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