Microhardness testing
Microhardness testing measures hardness of metal samples with low test forces to analyze thin surface layers and welds. It requires a finely polished metallographic specimen.
Physical-Chemical Mechanism of Action
Microhardness testing applies a very small, concentrated load to the specimen to measure its hardness. This process is often done under a microscope to analyze thin layers or specific microstructural constituents more accurately.
Metallurgical Relevance & Risks in Welding
Microhardness testing is crucial for quality assurance of welds and metallic components. It helps detect hardness variations that could lead to cracking or distortion. Incorrect hardness distribution can also affect the material's toughness and service life.
Workshop Practice & Instructions
For microhardness testing, the specimen must be finely polished. The test load should be precisely defined to obtain accurate results. Hardness readings are typically taken on the HB scale. For welds, hardness values should be in the range of the base metal to ensure no unwanted hardness variations are present.