Regarding the precautions for the heating of the inject […]
Regarding the precautions for the heating of the injection mold, there are four main steps, namely the forging process, preliminary heat treatment, quenching and tempering, and stress relief annealing. Here are the points for attention in each link.
1. Forging process.
This is an important link in the manufacturing process of working parts for injection molds. For high-alloy tool steel injection molds, technical requirements are usually put forward for the metallographic structure of the material such as carbide distribution. 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 used.
2. Preparation for heat treatment.
Everyone should pay attention to the different materials and requirements of the working parts of the injection mold. Use annealing, normalizing or quenching and tempering and other preliminary heat treatment processes to improve the organization, eliminate the structural defects of the forging blank, and improve the processing technology. The high-carbon alloy die steel can eliminate the network secondary cementite or chain carbide through proper preliminary heat treatment, spheroidize and refine the carbide, and promote the uniformity of carbide distribution. This will help ensure the quality of quenching and tempering and increase the life of the mold.
3. Quenching and tempering.
This is the key link in mold heat treatment. If overheating occurs during quenching and heating, it will not only cause greater brittleness of the workpiece, but also easily cause deformation and cracking during cooling, which will seriously affect the life of the mold. Special attention should be paid to prevent oxidation and decarburization when the die is quenched and heated, and the heat treatment process specifications should be strictly controlled. When conditions permit, vacuum heat treatment can be used. After quenching, it should be tempered in time, and different tempering processes should be used according to technical requirements.
Fourth, stress relief annealing.
After processing the parts of the injection mold, the stress relief annealing treatment should be carried out. The purpose is to eliminate the internal stress caused by rough machining, so as to avoid excessive deformation and cracks caused by quenching. For molds with high precision requirements, they need to undergo stress relief and tempering treatment after grinding or electrical machining, which is conducive to stabilizing the accuracy of the mold and improving the service life.