Three types of die steel

Die steel can be roughly divided into three categories: cold rolled die steel, hot rolled die steel and ductile iron, which are used for forging, stamping, cutting and injection molding in complex conditions.

Therefore, the die steel should have high hardness, strength, wear resistance, sufficient toughness, and high hardenability, hardenability and other processing properties according to the conditions of use of the die.

Due to the different use and difficult working conditions, the performance requirements of cast steel are also different.

Cold rolled dies: including cold forming dies, drawing dies, wire drawing dies, stamping dies, rolling dies, wire rolling dies, cold heading dies and cold extrusion dies, etc. Steel for cold work dies, depending on the working conditions of the tools used to manufacture it.

It must have high hardness, strength, wear resistance, adequate impact strength, high hardenability, hardenability and other process properties. Alloy tool steels used for such applications are usually high-carbon alloy steels with a carbon content greater than 0.80%.

Chromium is an important alloying element in these steels, and its mass fraction usually does not exceed 5%. However, for some steels with high wear resistance requirements and low deformation after quenching, the chromium content can be up to 13%, accompanied by the formation of large amounts of carbide.

The carbon content of the steel is also very high, up to 2.0%-2.3%. Cold work steel with high carbon content, its microstructure is mostly over-eutectic steel or Leydenite steel. Commonly used steels are high-carbon low-alloy steel, high-carbon high-chromium steel, chromium-molybdenum steel, medium-carbon chromium-tungsten steel, etc.

Hot rolling dies: divided into hammer forging, stamping, extrusion and injection molding, including hot stamping dies, punching dies, stamping dies, hot extrusion dies and metal injection dies.

In addition to the great mechanical stress, the hot deformation dies must also be subjected to repeated heating and cooling, resulting in great thermal stress. Hot stamping die steel should have high hardness, toughness, red-hardness, wear resistance and ductility.

It must also have good heat resistance, thermal fatigue resistance, thermal conductivity and corrosion resistance, and require high hardenability to ensure consistent mechanical properties across the cross section. For stamped steel, it must also have a surface layer that does not break when repeatedly heated and cooled and when exposed to liquids.

The impact and erosion characteristics of metal flow in the state. This type of steel is generally carbon mass fraction of 0.30% to 0.60% of the medium carbon alloy steel, for sub-eutectic steel, part of the steel into eutectic steel or over-eutectic steel. Commonly used steel: chromium manganese, chromium nickel, chromium tungsten, etc.

Plastic moulds: including thermoplastic plastic moulds and thermosetting plastic moulds. Plastic mold steel must have a certain strength, hardness, wear resistance, thermal stability and corrosion resistance and other properties.

In addition, also requires good processability, such as heat treatment deformation is small, good processing performance, good corrosion resistance, good grinding and polishing performance, good welding performance, high roughness, good thermal conductivity, stable size and shape under working conditions, etc. (plastic mold steel, Germany Saar, Germany Saar forging steel plant)