The hot working quality of the mold has a great influence on the performance and service life of the mold. In real life and work, our mold workshop requires continuous improvement in the design and production of various molds, and there will be problems in the specific operation. We will discuss and exchange the problems in the use of stamping molds with Shenzhen mold manufacturers
The quenching deformation and cracking of the working parts of the mould and the early fracture in the process of use are all related to the hot working process of the mould.
(1) Forging process, which is an important link in the manufacturing process of die working parts. For the mould of high alloy tool steel, the technical requirements for the metallographic structure such as carbide distribution are usually put forward. In addition, the forging temperature range should be strictly controlled, the correct heating specification should be formulated, the correct forging force method should be adopted, and the slow cooling or timely annealing after forging should be adopted.
(2) Prepare for heat treatment. According to the different materials and requirements of die working parts, the pre heat treatment processes such as annealing, normalizing or quenching and tempering should be adopted to improve the microstructure, eliminate the microstructure defects of forging blank and improve the processing technology. After proper preparation heat treatment, the network secondary cementite or chain carbide can be eliminated, the carbide can be spheroidized and refined, and the distribution uniformity of carbide can be promoted. In this way, the quenching and tempering quality can be guaranteed and the service life of the die can be improved.
(3) Quenching and tempering. This is the key link in the heat treatment of mould. If overheating occurs during quenching and heating, the workpiece will not only cause greater brittleness, but also easily cause deformation and cracking during cooling, which will seriously affect the service life of the die. During quenching and heating of die, special attention should be paid to prevent oxidation and decarburization. The heat treatment process specification should be strictly controlled. If conditions permit, vacuum heat treatment can be used. After quenching, it should be tempered in time, and different tempering processes should be adopted according to the technical requirements.
(4) Stress relief annealing. Die working parts should be treated with stress relief annealing after rough machining to eliminate the internal stress caused by rough machining, so as to avoid excessive deformation and cracks caused by quenching. For the mold with high precision, stress relief tempering treatment is needed after grinding or electrical machining, which is conducive to stabilizing the mold precision and improving the service life.