ASTM E18-24 PDF

Full title and description

ASTM E18-24 — Standard Test Methods for Rockwell Hardness of Metallic Materials. This document specifies procedures for determining Rockwell and Rockwell superficial hardness of metallic materials, requirements for Rockwell hardness testing machines (including portable machines when applicable), standardization of indenters and test blocks, and related verification and reporting practices.

Abstract

ASTM E18-24 provides standardized Rockwell and superficial Rockwell hardness test methods used to obtain indentation hardness values on metallic materials. The standard covers test procedures, machine and indenter requirements, verification and calibration methods (direct and indirect), annexes with machine verification and standardization procedures, guidance on minimum test-piece thickness, and corrections for testing on convex cylindrical surfaces. It also includes nonmandatory appendixes addressing correlations to tensile strength and procedures for estimating measurement uncertainty.

General information

• Status: Active (current designation E18-24).
• Publication date: April 1, 2024 (designated E18-24).
• Publisher: ASTM International.
• ICS / categories: 77.040.10 — Mechanical testing of metals / hardness testing.
• Edition / version: E18-24 (2024 edition).
• Number of pages: 38 pages (typical published PDF length).

Scope

These test methods cover determination of Rockwell hardness and Rockwell superficial hardness of metallic materials using the Rockwell indentation principle. The standard provides requirements for testing machines (including provisions for portable Rockwell hardness machines that can meet E18 verification requirements), procedures for performing tests on regular and superficial Rockwell scales, annexes for machine verification and standardization of indenters and test blocks, guidance on minimum test-piece thickness, and corrections for convex cylindrical surfaces. Nonmandatory appendixes provide tables and examples (for example, hardness-to-tensile correlations and uncertainty estimation).

Key topics and requirements

• Definitions and Rockwell hardness scales (regular and superficial) and their applicable ranges.
• Test procedures: preliminary force, total force, dwell times, and calculation of Rockwell hardness values.
• Machine requirements and verification methods — direct and indirect verification of testing machines (including portable machine provisions and verification distinction relative to Test Method E110).
• Standardization and calibration of indenters (diamond cones and steel/hardmetal balls) and Rockwell hardness test blocks.
• Annexes addressing machine verification (A1), standardizing machines (A2), indenters (A3), test blocks (A4), minimum thickness guidance (A5), and convex surface corrections (A6).
• Units: specification in SI units (Newtons, millimetres) with historical kgf/in values provided for information.
• Nonmandatory appendixes with hardness–tensile correlations and uncertainty estimation guidance.

Typical use and users

Used by metallurgical and materials testing laboratories, manufacturing quality and inspection departments, calibration and standards laboratories, research institutions, and suppliers of hardness testing equipment. Typical applications include incoming inspection, production quality control, material qualification and acceptance testing, and laboratory intercomparisons. The standard provides the traceability and verification practices required for routine and reference testing.

Related standards

Key related standards and documents include ASTM E110 (verification of portable Rockwell machines where indirect verification is used), ASTM E10 (Brinell hardness), ASTM E384 (Vickers/Knoop hardness), ASTM A370 (mechanical testing references for steel which cross-references E18 for Rockwell testing), and the ISO Rockwell series (ISO 6508 parts covering Rockwell testing and verification). These documents are commonly referenced together for instrument verification, alternative hardness methods, and international harmonization.

Keywords

Rockwell hardness, Rockwell superficial hardness, hardness testing, hardness scales (HRA, HRB, HRC, etc.), indenter standardization, machine verification, test blocks, portable hardness tester, calibration, ASTM E18-24.

FAQ

Q: What is this standard?

A: ASTM E18-24 is the ASTM International standard that specifies test methods for measuring Rockwell and superficial Rockwell hardness of metallic materials, including machine and indenter requirements and verification procedures.

Q: What does it cover?

A: It covers the test procedure (preload, total load, dwell times), applicable Rockwell scales, requirements for testing machines and indenters, verification and calibration methods (direct and indirect), annex guidance (machine verification, indenter and test-block standardization), minimum specimen thickness, and corrections for convex surfaces. Nonmandatory appendixes provide correlation tables and uncertainty examples.

Q: Who typically uses it?

A: Materials and metallurgical laboratories, production and quality control personnel, calibration laboratories, hardness equipment manufacturers, and inspectors who perform Rockwell hardness testing.

Q: Is it current or superseded?

A: E18-24 is the 2024 designation of the E18 test methods and is the current ASTM E18 edition as of the 2024 publication (designated E18-24). Users should confirm if any later revisions or work items have been initiated after 2024 for future updates.

Q: Is it part of a series?

A: E18 is part of ASTM’s test-method suite for hardness testing and is commonly used alongside related ASTM standards (E10, E110, E384) and international standards (ISO 6508 series) for broader hardness testing and verification practices.

Q: What are the key keywords?

A: Rockwell, Rockwell superficial, hardness, HRC, HRB, HRA, indenter, verification, calibration, test blocks, ASTM E18-24.