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 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	Appendix X1
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.

ASTM E18 - 22

Standard Test Methods for Rockwell Hardness of Metallic Materials

Published:

1 May 2022

Withdrawn:

16 May 2024