1. Forging process, which is an important part of the m […]
1. Forging process, which is an important part of the manufacturing process of mold parts. For molds of high alloy tool steels, technical requirements are often imposed on metallographic structures such as material carbide distribution. In addition, the forging temperature range should be strictly controlled, the correct heating specification should be established, the correct forging force method should be used, and the post-forging slow cooling or timely annealing should be carried out.
2. Prepare for heat treatment. Pre-heat treatment processes such as annealing, normalizing or quenching and tempering should be used depending on the materials and requirements of the mold working parts to improve the structure, eliminate the structural defects of the forged blank, and improve the processing technology. The high-carbon alloy die steel can eliminate the reticulated secondary cementite or chain carbide after appropriate preliminary heat treatment, so that the carbide is spheroidized and refined, and the uniformity of carbide distribution is promoted. This is beneficial to ensure the quality of quenching and tempering and improve the life of the mold.
3. Quenching and tempering. This is the key link in the heat treatment of the mold. If the superheat occurs during quenching, not only will the workpiece cause greater brittleness, but also cause deformation and cracking during cooling, which seriously affects the life of the mold. Special care should be taken to prevent oxidation and decarburization during die quenching. The heat treatment process specification should be strictly controlled. Vacuum vacuum heat treatment can be used if conditions permit. After quenching, it should be tempered in time, and different tempering processes should be adopted according to technical requirements.
4. Stress relief annealing. The working parts of the mold shall be subjected to stress relief annealing after roughing, with the purpose of eliminating internal stress caused by roughing, so as to avoid excessive deformation and cracking caused by quenching. For molds with high precision requirements, it needs to be subjected to stress-relieving and tempering after grinding or electric machining, which is beneficial to stabilize mold precision and improve service life.
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