The ASTM E18-22 standard specifies a test method for rockwell hardness of metal materials. This method assesses the hardness value of materials by applying a certain load on the metal surface and measuring the depth of indentation. The standard covers the scope of application and test steps of different rockwell hardness scales (such as HRA, HRB, HRC, etc.), and is suitable for the hardness determination of various metal materials. The test method is easy to operate, fast and has high repeability, and is widely used in material performance testing, quality control and material selection. Through this standard, users can accurately evaluate the hardness of metal materials and provide important performance data for processing, heat treatment and application.