Core pin to obtain the desired hardness of heat treatment, heat treatment is necessary to stress the inner parts of precision die mold part is controlled so that when the parts processing and post-processing dimensional tolerances, geometric tolerances can be stabilized, the role of different parts of the material, with different heat treatments. The process is to be considered is the economic, material hardenability, hardened, too heat-sensitive and decarbonization sensitivity. With the development of the mold industry in recent years, the use of many types of materials, in addition to CrWMn, Cr12,40Cr, GCr15, Cr12MoV, 9Mn2V carbide, the large number of work intensity, force demanding die, punch, optional New material alloy powders, such as S2, S3, V10, APS23S1, G2, G3, G4, G8, and so on. Such materials have high thermal stability and good organizational status. Usually the workpiece is retained after quenching stress, easily lead to subsequent or finishing work cracking should be hot parts after quenching and tempering, quenching eliminate stress. Complex shape, inside and outside corner more artifacts, sometimes not enough to eliminate the quenching and tempering stress the need to de-stress before finishing annealing or aging treatment times, the full release of stress. Different approaches according to different requirements. With Cr12 for the material parts, for example, in the rough quenching, cooling only when there is hardening: air cooling (heating the workpiece in the air after cooling, this method is simple, the workpiece deformation is small, but the hardness low, easily oxidized surface suitable for small size, high precision, uneven thickness of the workpiece), oil cooling (after the workpiece is heated in an oil, cooled to 300 ℃ ~ 200 ℃, remove the cooling in air. This method simple, high hardness of the workpiece, but large deformation, deformation of the workpiece is easy to produce, for larger sizes, the simple shape of the workpiece), the clamping plate in the cooling air (heated workpiece placed two iron or pressed between copper and cooled in air. This method is relatively complex, but the workpiece deformation is small, only suitable for a particular shape of the workpiece), quenching (the workpiece is heated above the rear Ms point temperature of nitrate in After staying a certain time, to be consistent with the work inside and outside temperature, remove the cooling in air. This method can ensure the hardness of the workpiece, and reducing the deformation of the workpiece, is widely used in complex shape of the workpiece deformation required). Such as V10, APS23 alloy powder and other parts, which is likely to withstand the high-temperature tempering, secondary hardening process can be quenching, 1040 ℃ ~ 1080 ℃ quenching, and then 490 ℃ ~ 520 ℃ tempering and many times, You can obtain high impact toughness and stability, with chipping as the main failure mode of the mold is applicable.
