GB/T 230.2-2012 specification for hardness gauge used in rockwell hardness test of metal materials. It focuses on hardness gauge of 11 kinds of scales from A to T, and specifies the inspection and calibrate process in detail. Clarify the accuracy requirements of hardness gauge at different stages, covering initial use, regular and maintenance of calibrate. Through systematic inspection of the mechanical structure of hardness gauge, loading system, etc., to ensure its measurement accuracy. Standardized inspection and calibrate can ensure the reliability of rockwell hardness test data and provide a solid foundation for metal material performance evaluation. It is widely used in metal production, Quality control and other fields.