Mold heat treatment is an important means for improving the hardness properties of steel materials. It is generally performed after the mold has been opened and the heat treatment is carried out before the finishing process. However, there is a risk in the processing process. Improper handling can cause cracks in the steel material. Scrap, then what are the reasons for the plastic mold steel exception?
1) Severe mesh carbide segregation exists in the mold material.
2) There is machining or cold-forming stress in the mold.
3) Improper operation of the mold heat treatment (too fast heating or cooling, improper selection of quenching cooling medium, cooling temperature is too low, cooling time is too long, etc.).
4) The shape of the mold is complex, uneven thickness, with sharp corners and thin threaded holes, etc., so that the residual thermal stress and tissue stress is too large.
5) The heating temperature of the plastic mold during quenching is too high to cause overheating or overheating.
6) The quenching of the mold is not timely or the tempering holding time is insufficient.
7) Mold Rework When quenched and heated, quenching is again performed without intermediate annealing.
8) Mold heat treatment, improper grinding process.
9) After EDM of the mold heat treatment, there are high tensile stress and micro-cracks in the hardened layer.