- ①The use performance of the material should have high hardness (58~64HRC) and high strength, and have high wear resistance and sufficient toughness, small heat treatment deformation, and a certain degree of thermal hardness;
- ②Good process performance. The processing and manufacturing process of die working parts is generally more complicated. Therefore, it must be adaptable to various processing techniques, such as forgeability, machinability, hardenability, hardenability, quenching crack sensitivity and grinding workability.
Usually according to the material characteristics of the stamping parts, production batch, precision requirements, etc., the performance of the mold material is selected, while taking into account its manufacturability and economy. Heat treatment: quenching and tempering. The thermal processing quality of the mold has a great impact on the performance and service life of the mold.
- 1) Forging process: This is an important link in the manufacturing process of mold working parts. It is also necessary to strictly control the forging temperature range, formulate the correct heating specifications, adopt the correct forging force method, and slow cooling or timely annealing after forging.
- 2) Preliminary heat treatment: annealing, normalizing or quenching and tempering should be used according to the different materials and requirements of the mold working parts to improve the structure, eliminate the structural defects of the forging blank, and improve the processing technology. High-carbon alloy die steel can eliminate 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 the heat treatment of the mold. 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 adopted according to the technical requirements.
- 4) Stress-relieving annealing: After rough machining, mold working parts should be subjected to stress-relieving annealing treatment. 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.