What is hot work die steel Hot work die steel refers to the alloy tool steel suitable for the production of hot deformation of the metal mold, such as hot forging die, hot extrusion die, die casting die, hot heading die and so on. Because the hot work mold is working under high temperature and high pressure conditions for a long time, the mold material is required to have high strength, hardness and thermal stability, especially high thermal strength, thermal fatigue, toughness and wear resistance.

Hot working die steel composition characteristics

1. Carbon content

It is generally medium carbon, and the mass fraction of carbon is 0.3% to 0.6%. Ensure that the material has higher strength and hardness, higher hardenability and better hope, toughness.

2. Alloying element

The alloying elements added are Cr, Mn, Si, Ni, W, Mo, V and other alloying elements. Among them, the role of Cr, Mn, Si and Ni alloy elements is to strengthen ferrite and improve hardenability. W, Mo alloy elements are in order to prevent tempering brittleness, Cr, W, Si alloy elements can improve the phase change temperature, so that the mold in the process of alternating heating and cooling without phase change and greater volume change, so as to improve its ability to resist thermal fatigue. In addition, W, Mo, V, etc. are precipitated in the form of carbide during tempering to produce secondary hardening, so that hot work die steel still maintains a fairly high hardness at a higher temperature, which is one of the important conditions for the normal work of hot work die steel, Cr, 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 alloying element content and the performance after heat treatment, can be divided by use, and can also be classified according to the alloying element.

(1) According to the use can be divided into hot forging die steel, hot extrusion die steel, die casting die steel, hot blanking die steel.

(2) According to heat resistance can be divided into low heat resistant steel (350 ~ 370℃), medium heat resistant steel (550 ~ 600℃), high heat resistant steel.

(3) According to its unique properties, it is divided into high toughness hot work die steel, high heat strength hot work die steel, high wear resistance hot work die steel.

(4) According to the alloying element classification can be divided into low alloy hot working die steel (tungsten, chromium and molybdenum), medium alloy hot working die steel and high alloy hot working die steel (tungsten molybdenum and chromium molybdenum); 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 Chrome-tungsten high alloy hot work die steel are not as good as those of tungsten and molybdenum, but the cold and thermal fatigue resistance and toughness are higher than those of tungsten and molybdenum.