The hardness of the oval gasket can be confirmed through two methods: indentation method and scratch method. The indentation method is commonly used in the laboratory, while the scratch method is suitable for rapid on-site testing.
1、 Indentation method
Brinell hardness (HB): Press the metal surface with a test force of 100kgf, measure the indentation diameter to calculate the hardness value, suitable for common materials such as carbon steel and stainless steel.
Rockwell hardness (HRB/HRC): HRB (100kgf) is used for medium hardness materials such as soft iron, while HRC (150kgf) is used for high hardness materials such as alloy steel.
Vickers hardness (HV): Measuring diagonal length with a test force of 4.9N, it has high accuracy and is commonly used for ultra-thin gaskets or special alloys.
2、 Scratch method
Using the Mohs hardness tool to compare the depth of scratches and quickly determine the hardness level of the gasket, but the accuracy is relatively low.
During the Brinell hardness measurement process, it is important to avoid excessive errors in indentation diameter.