ISO 3738-1:1982

Overview

ISO 3738-1:1982: Hardmetals - Rockwell Hardness Test (Scale A) - Part 1: Test Method is an international standard that specifies the procedure for measuring the Rockwell hardness (A scale) of hardmetals. Developed and maintained by the International Organization for Standardization (ISO), this standard replaces ISO 3738:1976, incorporating updates to ensure improved accuracy and consistency.

The document outlines key principles, definitions, apparatus requirements, and test procedures for conducting reliable Rockwell hardness tests on cemented carbides and other hardmetals. It is widely used in quality control, research, and manufacturing environments where precise mechanical property measurements are essential.

Key Topics

• Principle of the Test: Details the process of forcing a conical diamond indenter into a hardmetal test piece using specific forces and measuring the permanent indentation depth.
• Apparatus and Equipment:
  • Testing machine capable of accurate force application and measurement.
  • Certified diamond indenter conforming to ISO verification standards.
  • Standard hardmetal test blocks for calibration and verification.
• Symbols, Designations, and Parameters: Defines measurement variables such as indenter angle, tip radius, test forces, and calculation of HRA values.
• Test Piece Preparation:
  • Minimum required thickness (1.6 mm) and surface roughness.
  • Specifics for preparing flat or curved surfaces.
  • Requirements for removing surface layers to avoid test interference.
• Testing Procedure:
  • Sequence for applying preliminary and additional test forces.
  • Number and distribution of indentations per sample.
  • Measurement and averaging of results, including rounding rules.
• Expression of Results: Calculation and reporting of hardness values in HRA units, following specified precision guidelines.
• Test Report Requirements:
  • Reference to the ISO standard.
  • Full traceability of test details, sample identification, and results.

Applications

ISO 3738-1:1982 is crucial for organizations involved in:

• Powder Metallurgy: Ensuring consistent quality and performance of sintered hardmetals for cutting tools, wear-resistant parts, and inserts.
• Quality Assurance: Standardizing hardness measurement in manufacturing environments to meet customer and regulatory requirements.
• Material Research and Development: Providing repeatable, comparable data for material property investigation and development of novel hardmetal compositions.
• Inspection and Certification: Serving as a basis for third-party assessments, incoming goods inspection, and production control, ensuring products meet international benchmarks.

Utilizing this standard helps achieve reliable, comparable Rockwell hardness data, improving decision-making and product quality throughout the value chain.

Related Standards

To ensure holistic hardness testing and calibration, related ISO standards often used alongside ISO 3738-1:1982 include:

• ISO/R 80: Rockwell hardness test (B and C scales) for steel - referenced for general procedure alignment.
• ISO/R 716: Verification of Rockwell B and C scale hardness testing machines - for ensuring machine accuracy and indenter conformity.

Following these related documents provides a comprehensive foundation for mechanical property testing in metal and hardmetal industries, and helps organizations align with globally recognized best practices in hardness testing.

Keywords: ISO 3738-1, hardmetals, Rockwell hardness test, scale A, test method, hardness testing standard, powder metallurgy, mechanical tests, quality control, ISO standards.