For alloy steels, the quenching deformation can be austempered or graded quenching using potassium nitrate and sodium nitrite hot baths. This method is particularly suitable for processing stamping dies with complex shapes and dimensional requirements*. Some porous mould parts (such as porous die), the austempering time should not be too long, otherwise it will cause the aperture or hole distance to become larger. Vacuum gas quenching can also be used. When the gas quenching effect is not good, it is recommended to use a professional vacuum quenching oil.
For some wire-cutting stamping parts, prior to wire-cutting, staged quenching and multiple tempering (or high-temperature tempering) heat treatment processes should be used to improve the hardenability of the parts and to make the internal stress distribution uniform. In a state of less internal stress. The smaller the internal stress, the smaller the tendency to deform and crack after wire cutting.
Before the parts are taken out of the furnace and placed in the coolant, they should be placed in the air for proper pre-cooling and then quenched in the coolant. This is one of the effective ways to reduce the quenching deformation of the parts and prevent the parts from cracking. After the mould part is placed in the coolant, it should be rotated properly and the direction of rotation changed. This will help maintain a uniform cooling rate of the part, which can significantly reduce the deformation and prevent the tendency of cracking.