This part of the GB/T 231.1-2009 focuses on the brinell hardness test method of metal materials. It describes the test principle, specifies the requirements of equipment accuracy, etc., and guides the preparatory specification of the sample. Detailed instructions on how to select the appropriate test force and standardize the operation process of the indenter pressing into the metal material, including loading time, holding time and other key links. By unifying the test method, the brinell hardness of metal materials can be accurately determined, providing basic data for the quality control and performance evaluation of metal materials. It is widely used in metal processing, Quality control and other fields to ensure the accuracy and reliability of the test results.