After quenching D2 cold working die steel and then ultra-low temperature treatment in an industrial refrigerator at 196 ℃, the retained austenite can be eliminated and all martensite can be obtained, and the microstructure can be further refined. After ultra-low temperature treatment, the Rockwell hardness (HRC) of D2 steel is increased by 4 units, the… Read more Ultra low temperature treatment of D2 cold working die steel