How to prevent heat distortion

To prevent heating deformation, it is best to heat slowly and perform pre-heat treatment. When selecting the preheating temperature for general steels, the preheating temperature can be selected according to the following criteria: (1) The preheating temperature is below the transformation point, for example, ordinary steel is about 650 ~ 700 ℃, and high speed steel is about 800 ~ 850 ℃ or so. (2) The preheating temperature is about 500 ° C. (3) Two-stage pre-heating, first pre-heating at about 500 ° C, and after preheating for a period of time, raise the pre-heating temperature to below the A1 abnormality point. (4) Three-stage preheating. For large steels with high content of alloys, such as high-speed steel, sometimes the third stage of preheating is required at 1000 ~ 1050 ℃.