Abstract: Safety production of oil-gas well is directly affected by the forming grinding quality of non-API thread gauge. Spiral tooth, up to IT3~IT4 level of dimensional accuracy, fatigue resistance performance (up to 20 000 cycle time) under severe service condition, all of these requirements have close relation with the heat treatment and grinding processes which used in the machining of thread gauge. However, in the final grinding of thread gauge, surface defects on tooth such as grinding burn on the flange, grinding crack are often happened. These defects would significantly reduce the abrasion resistance and service life of the gauge. In order to solve this situation, based on favorable usability and service properties of the gauge, this topic proposed a method to optimize the heat treatment of die steel which is the workpiece material and grinding parameters in parallel. Studies involve quantitative description of the relationship between heat treatment of die steel and its grinding performance, the grinding burn and crack could be solved by this technique. Heat treatment and surface grinding experiments are carried out on die steel, the results show that the optimized heat treatment improves the grinding quality of the material effectively. It also indicated the combination of optimized heat treatment and grinding parameters was the necessary condition in grinding of gauge material.

Key words: forming grinding, grinding burn, grinding crack, heat treatment, thread gauge