When manufacturing complex and precise molds, when the segregation of carbides in the mold steel used is small, the carbides of some mold steels will be severely segregated. For such mold steels, the ingots of carbides are broken. These die steels are reasonably forged to reduce the distribution of carbides. There are also some molds that are large in size and cannot be forged. For these molds, a double-fine solution treatment can be used, so that the corners of the mold are rounded, the carbides are refined, and the degree of deformation of the heat treatment of the mold is reduced.
For the molds, before and after the semi-finishing, the mold is annealed, and the stress-relieving method can be used to reduce the quenching temperature and reduce the residual stress after quenching. In order to reduce the residual stress of quenching, some quenching processes such as quenching, fractional quenching, and oil-cooling may also be employed. These measures can reduce the residual stress of the mold after quenching, thereby reducing the degree of deformation of the mold after heat treatment.
When designing the mold, it is necessary to reduce the degree of structural asymmetry of the mold and the degree of thickness and disparity. At the thin and thick boundary of the mold, a smooth transition structure design is adopted. It is necessary to be familiar with some laws of mold deformation. According to these laws, the processing amount of mold manufacturing is reserved, so that after quenching, the mold will not be scrapped due to deformation. It is also possible to use a combined structure to cool the mold after quenching, reducing the degree of deformation of the heat treatment of the mold.
When the complex mold is heated, it should be heated slowly. The degree of deformation of the mold vacuum heat treatment is much lower than that of the salt bath furnace. The mold preheating method is adopted for some high alloy molds. The method of secondary preheating adopts a preheating method for the mold composed of the low alloy, and these measures can reduce the degree of heat treatment of the mold.