The first is hardness, which is the main technical index of die steel. In order to keep its shape and size unchanged under the action of high stress, the die must have sufficient hardness. The hardness of cold work die steel is generally maintained at about HRC60 at room temperature, and that of hot work die steel is generally required to be maintained in the range of hrc40 ~ 55 according to its working conditions. For the same steel, within a certain range of hardness, hardness is directly proportional to deformation resistance; However, there may be obvious differences in plastic deformation resistance between steel grades with the same hardness value but different composition and structure.

Secondly, the red hardness is a hot working die working at high temperature. It is required to maintain the stability of its structure and performance, so as to maintain a sufficiently high hardness. This property is called red hardness. Carbon tool steel and low alloy tool steel can generally maintain this property in the temperature range of 180 ~ 250 ℃, and chromium molybdenum hot work die steel can generally maintain this property in the temperature range of 550 ~ 600 ℃. The red hardness of steel mainly depends on its chemical composition and heat treatment process.
Thirdly, compressive yield strength and compressive bending strength the mold is often subjected to high strength pressure and bending during use, so the mold material is required to have certain compressive strength and bending strength. In many cases, the conditions for carrying out the compression test and bending test are close to the actual working conditions of the die (for example, the measured compression yield strength of die steel is more consistent with the deformation resistance exhibited by the punch when it is working). Another advantage of bending test is that the absolute value of strain is large, which can reflect the difference of deformation resistance between different steel grades and under different heat treatment and microstructure more sensitively. Graphite mould, Dongguan graphite mould, Shenzhen graphite mould, Guangdong graphite mould, Foshan graphite mould