Methods to prevent deformation: First of all, during the heat treatment of forgings, the parts to reduce deformation should be placed as vertically as possible, secondly, placed vertically at the bottom of the furnace, and thirdly, supported horizontally by two points , the fulcrum position is between one-third and one-quarter of the total length, and the fourth is placed flat on the heat-resistant steel tooling. Secondly, during the cooling process of parts, the type of quenching medium, cooling performance, hardenability, etc. are related to deformation. Changes in cooling performance can be adjusted by changing the viscosity, temperature, liquid surface pressure of the medium, using additives, stirring, etc. The higher the viscosity of the quenching oil and the higher the temperature, the smaller the elliptical deformation. In the static state, the deformation is small. The following methods can effectively reduce deformation: ① Salt bath quenching; ② High temperature oil quenching; ③ QSQ method; ④ Reduced pressure quenching; ⑤ Three-stage quenching in one tank. Salt bath quenching is similar to high-temperature oil quenching. Both are quenched at the martensite transformation temperature, which increases the uniformity of the martensite transformation. QSQ is double liquid quenching. Decompression quenching reduces the liquid surface pressure of the quenching medium, thereby prolonging the vapor film stage. The cooling rate in the high-temperature area decreases, so that the cooling rate of each part of the part is uniform. The structure of three-stage quenching in one tank is simple. First, the parts are oil-cooled from the quenching temperature to a temperature slightly higher than the Ms point. Then they are taken out of the furnace and kept in the atmosphere to make the overall temperature of the parts uniform. Then they are oil-cooled again to make the martensitic phase transformation. Proceeding evenly, the irregularities in deformation are greatly improved.