SIST EN ISO 4545-1:2023 PDF

Overview

EN ISO 4545-1:2023 / ISO 4545-1:2023 specifies the standardized Knoop hardness test method for metallic materials and many inorganic coatings. It defines test forces, measurement limits and procedural requirements to obtain reproducible Knoop hardness numbers (HK). This edition (adopted by CEN as EN ISO 4545-1:2023) updates scope to explicitly include metallic and other inorganic coatings and adds user routine verification requirements.

Key topics and requirements

• Test force range: from 0.009807 N to 19.613 N (covering micro- to low-load Knoop testing).
• Minimum indentation size: the long diagonal of the indentation shall be ≥ 0.020 mm. Determination from smaller indentations is outside the scope due to optical measurement limits and indenter geometry uncertainties.
• Coatings: method applies to metallic and other inorganic coatings (electrodeposited, autocatalytic, sprayed, anodic on aluminium) for:
  • measurements normal to the coated surface, and
  • measurements on cross-sections, if coating characteristics (smoothness, thickness) permit accurate diagonal readings.
  • Thickness limits: not applicable for coatings thinner than 0.007 mm for surface testing, or thinner than 0.020 mm for cross-section testing.
• Measurement and calculation: specifies diagonal measurement, hardness number calculation, and reporting requirements for Knoop hardness (HK).
• Periodic verification: a user-level verification procedure is included for routine checking of the testing machine, indenter and diagonal measuring system in service.
• Uncertainty and traceability: the standard addresses uncertainty considerations and provides normative/ informative annexes on verification, calibration and traceability.

Applications and users

• Quality assurance and hardness testing laboratories performing microhardness measurements.
• Metallurgists and materials engineers evaluating microstructure, surface treatments and thin coatings.
• Coating manufacturers and surface-engineering practitioners who require standardized hardness data for coatings and plated layers.
• Industries with small-feature or thin-layer components: electronics, aerospace, automotive, and surface-treatment suppliers.
• Test equipment manufacturers and calibration services using the method for routine verification and machine calibration planning.

Related standards

• ISO 4545-2 - Verification and calibration of Knoop testing machines.
• ISO 4545-3 - Calibration of Knoop reference blocks.
• ISO 14577-1 - Instrumented indentation testing (recommended for hardness determination from smaller indentations than covered here).

Keywords: Knoop hardness test, EN ISO 4545-1:2023, ISO 4545-1, metallic materials, coatings, microhardness, test force range, hardness testing, periodic verification.