Overview
SIST EN ISO 3738-1:2010 specifies the Rockwell hardness test (scale A) method specifically for hardmetals, providing a standardized procedure globally recognized in the metalworking and powder metallurgy industries. This standard cancels and replaces ISO 3738:1976 and incorporates detailed principles, definitions, designations, apparatus requirements, test specimen preparation, testing procedures, result expressions, and reporting guidelines. It is critical for ensuring consistent and reliable hardness measurement of hardmetals using the Rockwell scale A.
Developed by ISO Technical Committee ISO/TC 119, this standard underpins mechanical testing practices in powder metallurgy and hardmetal industries, ensuring testing methods are precise, repeatable, and comparable across international laboratories.
Key Topics
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Scope and Application
The standard applies exclusively to hardmetals tested using the Rockwell hardness test scale A. It outlines the test method including symbols, parameters, testing equipment, and specimen requirements.
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Principle of the Test
The test involves forcing a conical diamond indenter into the specimen surface with a preliminary load followed by an additional load, measuring the resulting indentation depth increase. Rockwell hardness (HRA) is calculated based on the permanent indentation depth under defined conditions.
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Test Parameters and Symbols
Includes detailed designation of parameters such as:
- Angle of diamond indenter cone (120° ± 0.5')
- Load forces (preliminary 98.07 N and additional test force 4903 N)
- Indentation depth readings
- Required specimen surface finish and thickness for accuracy.
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Testing Equipment Requirements
- Use of standardized diamond indenters conforming to ISO/R 716.
- Calibration and verification procedures with standard hardmetal test blocks.
- Guidelines on test machine performance and accuracy thresholds.
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Specimen Preparation