Designation

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 (ε) 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:

1.4

This standard includes nonmandatory information in the following appendixes that relates to the Rockwell hardness test.

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.

2. Referenced Documents

2.1

2.2

2.3

2.4

3. Terminology and Equations

3.1

3.2

4. Significance and Use

4.1

4.2

4.3

4.4

5. Principles of Test and Apparatus

5.1

5.2

5.3

5.4

5.5

5.6

5.7

5.8

6. Test Piece

6.1

6.2

6.3

6.4

6.5

7. Test Procedure

7.1

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8. Conversion to Other Hardness Scales or Tensile Strength Values

8.1

9. Report

9.1

9.2

9.3

9.4

9.5

10. Precision and Bias8, 9

10.1

10.2

10.3

10.4

10.5

10.6

10.7

10.8

10.9

10.10

10.11

11. Keywords

11.1

ASTM E18 - 24

Standard Test Methods for Rockwell Hardness of Metallic Materials

Published:

1 Apr 2024

Withdrawn:

9 Oct 2025