In the process of heat treatment, precision molds often have deformation. In order to prevent this bad phenomenon, as long as we grasp the deformation rules, analyze the causes, and adopt different methods to prevent mold deformation, we can reduce and control it. In general, the following methods can be taken to prevent the heat treatment deformation of precision and complex molds.

(1) Fair selection of materials. Micro deformation die steel (such as air quenched steel) with good material shall be selected for precision and complex dies. Die steel with severe carbide segregation shall be properly cast and carried out. For larger and non castable die steel, solution double refining heat treatment can be carried out.

(2) The die structure design shall be fair, the thickness shall not be too wide, and the shape shall be symmetrical. For the die with large deformation, the deformation rule shall be grasped, and the machining allowance shall be reserved. For the large, precise and complex die, the combined structure can be used.

(3) Precise and complex dies shall be pre heat treated to eliminate residual stress generated during machining.

(4) The heating temperature shall be reasonably selected and the heating speed shall be controlled. For precision and complex molds, slow heating, preheating and other balanced heating methods can be adopted to reduce the deformation of mold heat treatment.

(5) Pre cooling, staged cooling and quenching or warm quenching shall be adopted as far as possible under the condition of ensuring the die hardness.

(6) For precision and complex molds, vacuum heating quenching and cryogenic treatment after quenching shall be adopted as far as possible if the premise permits.

(7) For some precision and complex molds, the precision of the mold can be controlled by pre heat treatment, aging heat treatment, and quenching, tempering and nitriding heat treatment.

(8) When repairing mold defects such as sand hole, air hole and wear, repair equipment with small heat effect such as cold welding machine shall be selected to avoid deformation during repair.

There are many methods for heat treatment process operation, including such as hole plugging, hole binding, mechanical fixation, appropriate heating method, accurate selection of mold cooling direction and movement direction in the cooling medium, etc. Reasonable tempering heat treatment process is also an effective measure to reduce the deformation of precision and complex molds.