ASTM E384-22 PDF

Full title and description

ASTM E384-22 — Standard Test Method for Microindentation Hardness of Materials. This standard specifies procedures, equipment, and reporting requirements for performing microindentation hardness (microhardness) tests using Vickers and Knoop indenters over a wide range of test forces. It includes guidance on verification, calibration, measurement, and interpretation of microindentation hardness results for metals and other materials, and describes limitations and error sources associated with very low-force testing.

Abstract

ASTM E384-22 defines a standardized method for determining microindentation hardness values using Vickers and Knoop indenters at test forces from approximately 9.8 × 10⁻³ N to 9.8 N (1 to 1000 gf). The document addresses test equipment requirements, specimen preparation, indentation procedures, measurement of indent diagonals, calculation and reporting of hardness values, and analysis of precision, bias, repeatability and reproducibility. It also references verification and calibration practices and related hardness standards.

General information

• Status: Active.
• Publication date: Current edition approved October 1, 2022; document last updated November 8, 2022 (published fall 2022).
• Publisher: ASTM International.
• ICS / categories: 19.060 — Mechanical testing / Metallography.
• Edition / version: E384-22 (2022). Replaces E384-17.
• Number of pages: 40 pages.

Scope

This test method covers determination of microindentation hardness of materials by means of Knoop and Vickers indenters and test forces in the range from about 9.8 × 10⁻³ N to 9.8 N (1 to 1000 gf). It includes procedures for machine verification and calibration references, guidance on specimen preparation and measurement, and discussion of sources of error and their effects on precision and bias. The standard is applicable primarily to metals but may be applied to other materials where microindentation testing is appropriate.

Key topics and requirements

• Test methods for microindentation hardness using Vickers and Knoop indenters (geometry, measurement of diagonals/indents).
• Permitted test-force range: ~9.8 × 10⁻³ N to 9.8 N (1–1000 gf) and guidance on limitations at very low forces (≤25 gf) where indents <20 µm become qualitative.
• Requirements and recommendations for machine verification, calibration of hardness blocks, and traceability (references to Test Method E92 for block manufacture/calibration).
• Procedures for specimen preparation, measurement techniques, data reduction, reporting, and statistical treatment (repeatability, reproducibility, bias).
• Discussion of common error sources (surface preparation, indenter alignment, optical measurement limits) and how they affect results.
• Guidance on appropriate selection of indenter and force for case depth, thin sections, coatings, or phase-specific measurements.

These topics and requirements are described with practical recommendations for minimizing measurement uncertainty and ensuring consistent inter-laboratory results.

Typical use and users

Used by metallurgists, materials scientists, quality-control and testing laboratories, research and development teams, and manufacturers needing microhardness data for thin materials, coatings, surface-treated layers, individual microstructural phases, or small/fragile specimens. Common applications include case-hardness profiling, thin-film and coating evaluation, failure analysis, and correlation of microhardness to mechanical properties.

Related standards

Related and referenced standards include ASTM E92 (Vickers and Knoop hardness of metallic materials — calibration/manufacture of reference blocks), ASTM E140 (hardness conversion tables), ASTM E766 (calibrating magnification of SEM), and other Committee E04 practices concerning precision, bias, and uncertainty. E384-22 consolidates and updates relevant microindentation guidance previously split across earlier documents.

Keywords

microindentation, microhardness, microhardness testing, Vickers, Knoop, Knoop hardness, Vickers hardness, test force, indent diagonal, calibration, precision, repeatability, metallurgy, coatings, thin films.

FAQ

Q: What is this standard?

A: ASTM E384-22 is the Standard Test Method for Microindentation Hardness of Materials, providing procedures and requirements for microhardness testing using Vickers and Knoop indenters.

Q: What does it cover?

A: It covers test forces from about 9.8 × 10⁻³ N to 9.8 N (1–1000 gf), indenter types (Vickers and Knoop), measurement and calculation of hardness, machine verification and calibration references, specimen preparation, error sources, and statistical treatment of results.

Q: Who typically uses it?

A: Laboratories and practitioners in materials testing, metallography, manufacturing quality control, R&D, and any users who need precise microhardness measurements on small volumes, coatings, or microstructural features.

Q: Is it current or superseded?

A: The E384-22 edition is the current active edition as of its approval on October 1, 2022, and subsequent publication/update in November 2022; it supersedes the prior E384-17 edition.

Q: Is it part of a series?

A: Yes. E384 is part of ASTM Committee E04 on Metallography and is published within the ASTM annual books of standards (Vol. 03.01). It is associated with other hardness- and metallography-related standards (for example E92, E140, E766, and various E04 practices).

Q: What are the key keywords?

A: Microindentation, microhardness, Vickers, Knoop, hardness testing, calibration, test force, specimen preparation, precision, coatings, thin films.