Cr12 die steel is one of the representative steel grades of high carbon and high chromium cold working die steel. C2.00% ～ 2.30% and cr11.00% ～ 13.00% with very high content (mass fraction) belong to ledeburite steel, so they have high hardenability, hardenability and wear resistance, and the quenching deformation is small. However, when the carbide is not uniform, the deformation is multi-directional and irregular, and its poor microstructure is its main defect. It is difficult to improve the inhomogeneous carbides by heat treatment unless the powder metallurgy process is used. Cr12 die steel has poor impact toughness, thermal conductivity and high temperature plasticity, so it is necessary to pay attention to heating and forging process during hot working.
The die steel is also one of the cold working die steels in the world, but it has been gradually replaced by more excellent steels such as Cr12MoV, Cr12Mo1V1 or matrix steel. The die steel was introduced from X12 of the former Soviet Union and was included in the standard (yb-1957) in 1957. The same steel grades abroad are 210cr12 (ISO), skd1 (JIS) of Japan, DC1 of Datong special steel, CRD of Hitachi metal, k100 of Bailu company of Austria, sverer3 (uhB) of Sweden, etc.
Cr12 die steel is mainly used for cold working parts (punch and die) with high wear resistance and small impact load, and the female die of cold extrusion die. Due to its obvious advantages and disadvantages, its use is limited.