ISO 6508-1:2023

Overview

ISO 6508-1:2023 - "Metallic materials - Rockwell hardness test - Part 1: Test method" defines the standardized procedure for Rockwell regular and superficial hardness tests on metallic materials. It covers the full set of Rockwell scales (A, B, C, D, E, F, G, H, K and the superficial scales 15N, 30N, 45N, 15T, 30T, 45T), and applies to both stationary and portable hardness testing machines. The document is the primary reference for performing Rockwell hardness measurements, specifying indenter types, forces, test-piece preparation, environmental limits and procedural controls.

Key topics and technical requirements

• Test principle: Two-stage loading (preliminary force and additional force) with depth measurement; hardness value derived from indentation depth and scale-specific constants.
• Rockwell scales and parameters: Defined scales with corresponding indenters, preliminary/total test forces and scaling constants (tables for regular and superficial scales).
• Indenter specifications:
  • Spheroconical diamond indenter: 120° included angle, tip radius 0.2 mm (certified for specific scales).
  • Tungsten-carbide ball indenters: nominal diameters 1.5875 mm and 3.175 mm; steel balls allowed only for HR30TSm/HR15TSm (Annex A).
• Machine and calibration: Testing machines must meet requirements and verification procedures referenced in ISO 6508-2 and ISO 6508-3 (verification, calibration of machines and reference blocks).
• Test-piece preparation: Surface finish, freedom from scale/contamination, thickness requirements (Annex B) - minimum thickness rules tied to indentation depth.
• Environmental and procedural controls: Recommended laboratory temperature 10 °C to 35 °C; daily verification (Annex E); indenter inspection (Annex F); uncertainty assessment (Clause 9, Annex G).
• Special cases and corrections: Annexes cover thin products (A), corrections for convex cylindrical and spherical surfaces (C, D), and traceability/working groups (H, I).

Applications and who uses it

ISO 6508-1:2023 is used for:

• Quality control and acceptance testing in manufacturing (heat treatment, machining, hardening processes)
• Material certification and incoming inspection for metallic components
• Calibration laboratories and metrology services for hardness traceability
• R&D and failure analysis in metallurgy and materials engineering
• Field inspections using portable Rockwell hardness testers

Typical users: metallurgists, QA/QC engineers, testing laboratory technicians, machine manufacturers, and standards/compliance professionals.

Related standards (if applicable)

• ISO 6508-2 - Verification and calibration of testing machines and indenters
• ISO 6508-3 - Calibration of reference blocks
• Other product/material specific standards (e.g., ISO 3738-1, ISO 4498) that may override or supplement ISO 6508-1 requirements

Keywords: ISO 6508-1:2023, Rockwell hardness test, metallic materials, Rockwell scales, indenter specifications, hardness testing procedure, hardness calibration, portable hardness tester.