In 60s, Japan has been using the SKD11. From the beginning of 1975, with the popularity of EDM, Japan began to use high temperature tempering technology, but for SKD11, there is a high temperature tempering hardness than low temperature tempering hardness low.Moreover, with the expansion of TRD and CVD processing technology, to improve the high temperature tempering hardness of the increasingly high demand, so early in the 80s Japan Shanyang special steel company has developed QCM8, Datong special steel company has developed DC53 8%Cr steel. The carbon content of 8%Cr steel and Cr SKD11 only 2/3, so it can reduce the amount of eutectic carbides of Cr steel, and because the size of primary carbides is reduced, so it can improve the toughness and machinability of steel. In addition, although the high temperature tempering hardness of SKD11 is less than 60HRC, but the content of Mo is two times the SKD11 of 8%Cr steel high temperature tempering hardness can reach 60 ~ 62HRC, has been widely used.
In 90s, along with the improvement of cutting machinery and cutting tools, auto manufacturers to reduce the cost of mold of the increasingly high demand. To this end, the Japanese steel industry has developed to high frequency cutting of cold working die steel ----KD11S steel, the addition of S is beneficial to improve machinability of elements. Pay attention to the cutting of cold work die steel is an added cutting chemical elements contribute to the improvement of steel, can reduce the carbide materials. Also developed cutting with the same SKS very good material.
Around 2000, with the expansion of application of high strength steel, 8%Cr steel and the importance of cutting of cold die steel problems die mold sticking and die wear. In order to ensure cutting, and can improve the wear resistance, reduce the deformation of heat treatment and surface treatment after finishing work, the development of SLD-MAGIC Hitachi Metal Ltd in 2004.
The surface treatment technique can be applied in sheet metal stamping die based on TRD method and CVD method, then the treatment will be generated when the PVD method can improve the surface deformation characteristics and reduce the cost, expanding its application.With the application of PVD expansion, using TRD method and CVD method of making mold has a good sealing film of the problem, the original model originally restricted application application materials also increased. Kunshan cold die steel