中文
EN
Hot work die steel refers to alloy tool steel suitable for making a die for thermal deformation of metal, such as hot forging die, hot extrusion die, die casting die, hot heading die, etc. Since hot work molds work under high temperature and high pressure conditions for a long time, the mold materials are required to have high strength, hardness and thermal stability, especially high thermal strength, thermal fatigue, toughness and wear resistance.
Composition characteristics of hot work die steel
1. Carbon content
Generally it is medium carbon, and the mass fraction of carbon is 0.3%～0.6%. Ensure that the material has higher strength and hardness, higher hardenability and better hopeability and toughness.
2. alloy element
The alloying elements added include Cr, Mn, Si, Ni, W, Mo, V and other alloying elements. Among them, the role of Cr, Mn, Si, Ni alloy elements is to strengthen ferrite and improve hardenability. W, Mo alloy elements are to prevent temper brittleness, Cr, W, Si alloy elements can increase the phase transition temperature, so that the mold does not undergo a phase change during the alternating heating and cooling process and a large volume change occurs, thereby improving its resistance The ability to thermal fatigue. In addition, W, Mo, V, etc. precipitate in the form of carbides during tempering to produce secondary hardening, so that the hot work die steel still maintains a relatively high hardness at a higher temperature, which is important for the normal work of the hot work die steel. One of the conditions, Cr and Si can improve the oxidation resistance of steel.
Hot work die steel classification
There are many classification methods for hot work die steel, which can be classified according to the content of alloy elements and the performance after heat treatment. It can be classified according to use or alloy elements.
(1) According to the application, it can be divided into hot forging die steel, hot extrusion die steel, die casting die steel, and hot blanking die steel.
(2) According to heat resistance, it can be divided into low heat resistant steel (350～370℃), medium heat resistant steel (550～600℃), and high heat resistant steel.
(3) According to unique characteristics, it is divided into high toughness hot work die steel, high heat and strong hot work die steel, and high wear-resistant hot work die steel.
(4) According to the classification of alloy elements, it can be divided into low alloy hot work die steel (tungsten series, chromium series and molybdenum series), medium alloy hot work die steel and high alloy hot work mold steel (tungsten molybdenum series and chromium molybdenum series); Or divided into tungsten hot mold steel, chromium hot mold steel and chromium tungsten molybdenum hot mold steel. The high-temperature strength and thermal stability of chromium-tungsten high alloy hot work die steel are inferior to those of tungsten and molybdenum, while the cold and hot fatigue resistance and toughness are higher than those of tungsten and molybdenum.
