The thermal processing quality of mold processing and the performance of molds

The thermal processing quality of mold processing and the performance of molds

The thermal processing quality of molds has a significant impact on their performance and service life. In practical life and work, our mold workshop requires excellence in the design and production of various molds, and specific operations may encounter problems.

The quenching deformation and cracking of mold parts, as well as the early fracture during use, are all related to the hot working process of the mold.

(1) Forging technology is an important link in the manufacturing process of mold working parts.

For molds made of high alloy tool steel, technical requirements are usually put forward for the distribution of carbides and other metallographic structures in the material. In addition, the forging temperature range should be strictly controlled, the correct heating specifications should be formulated, the correct forging force method should be used, and slow cooling or timely annealing after forging should be carried out.

(2) Prepare for heat treatment.

Preparation heat treatment processes such as annealing, normalizing, or quenching and tempering should be adopted according to the different materials and requirements of the working parts of the mold, in order to improve the structure, eliminate the structural defects of the forged blank, and improve the processing technology. High carbon alloy mold steel can eliminate network secondary carbides or chain carbides through appropriate preparatory heat treatment, making carbides spheroidized and refined, and promoting uniform distribution of carbides. This is beneficial for ensuring the quality of quenching and tempering, and improving the service life of the mold.

(3) Quenching and tempering. This is a crucial step in mold heat treatment.

If overheating occurs during quenching and heating, it not only causes significant brittleness of the workpiece, but also easily causes deformation and cracking during cooling, seriously affecting the service life of the mold. Special attention should be paid to preventing oxidation and decarburization during quenching and heating of stamping dies. The heat treatment process specifications should be strictly controlled. If conditions permit, vacuum heat treatment can be used. After quenching, timely tempering should be carried out, and different tempering processes should be adopted according to technical requirements.

(4) Stress relief annealing.

Mold parts should undergo stress relief annealing treatment after rough machining, with the aim of eliminating the internal stress caused by rough machining, in order to avoid excessive deformation and cracks caused by quenching. For molds with high precision requirements, stress relief tempering treatment is required after grinding or electrical machining, which is beneficial for stabilizing mold accuracy and improving service life.