Die steel: matrix for die manufacturing (II)

Research and development of new die steel materials

Mr. Ukamura: DRM was developed by Japan’s Datong special steel in recent years. In order to achieve a high hardness and high toughness base high-speed steel, it can reduce the coarse carbides to the limit, increase the service life and reduce the mold cost.

The reason why it is called base high-speed steel is that it is different from ordinary high-speed steel in that after heat treatment, crystalline carbide (primary carbide) and precipitated carbide (secondary carbide) still exist and cannot be dissolved into the matrix, while DRM base high-speed steel can be dissolved into the matrix after heat treatment, reducing coarse crystalline carbide, So as to better restrain the occurrence of cracks and improve the toughness. In order to prevent the occurrence of large cracks, small cracks (fatigue cracks), wear and other conditions in the use of dies, it is necessary to improve the toughness, fatigue strength and hardness, which is also the necessity and particularity of DRM high hardness and high toughness base steel.

DRM series is divided into DRM1, DRM2 and DRM3, which can be applied to multiple ranges.

DRM1 is a base high-speed steel with high hardness and toughness that can not be achieved by ordinary hot work tool steel. Compared with the previous base high-speed steel, DRM1 has high toughness and is suitable for various hot and warm forging dies. Mainly used in hot forging punches and dies; Punch and die for warm forging. Its main features are: ① It can be used under the highest hardness of 58HRC. ② High hardness, high toughness and good heat crack resistance. ③ It has the same level of micro structure as the hot stamping die steel, and has high toughness compared with the current high-speed steel matrix. ④ High softening resistance and high temperature strength. ⑤ Due to the special dissolution, there are few non-metallic inclusions and the homogeneity is excellent.

DRM2 is a kind of base high-speed steel which can be widely used for pressing tools in warm and cold rooms under severe conditions. It can achieve higher hardness and toughness than the previous base high-speed steel, and is suitable for various temperature, temperature forging, cold forging and powder metallurgy dies. Mainly used in warm forging punches and dies; Cold forging punch and die. Its main features are: ① It can be used under the highest hardness of 62HRC. ② The microstructure is fine, the toughness value is high, and the fatigue property is good. ③ The hardenability is good, and the quenching of coarse diameter steel and vacuum heat treatment can also maintain high performance. ④ Due to the special dissolution, there are few non-metallic inclusions and the homogeneity is excellent.

DRM3 is improved on the previous MH85, and its high hardness and high toughness are suitable for high speed steel corresponding to vacuum quenching of high-precision product forming. Applicable to various cold room molds. Mainly used in cold forging punches and dies; Cold work roll and engraving roll; Vacuum quenched high speed tool steel and tools. Its main features are: ① It can be used under the highest hardness of 66HRC. ② The carbide is fine, with high toughness and fatigue strength compared with SKH51. ③ The hardenability is good, and the coarse diameter steel and the quenching in the vacuum heat treatment furnace can also maintain high performance. ④ Due to the special dissolution, there are few non-metallic inclusions and the homogeneity is excellent.