A New Hot Working Die Steel with Improved Hardenability "DH31-SS1"

The strongly commercial interests have been focused on hot working die steels with improved hardenability to attain higher impact value and ensure adequate dies life even in the larger mass blocks. Hardenability, avoiding pearlite transformation and attain a finer bainitic microstructure, is quite important on quenching of large die blocks. In addition strength of die is essential to improve sensitivity for ware at elevated temperature. In this paper, several properties such as hardnenability, inpact value, fracture toughness and high temperature strength of newly developed hot working die steel 'DH31-SS1' will be represented. The given results by comparing with conventional hot working die steel DHA1-ES (corresponding to AISI H13) are as follows. (1) Retarded quenched material has finer bainitic microstructure and superior impact value of 30 J/cm2. (2) Stress of resistance to deform at 973 K after short time holding is higher from 100 MPa upto 150 MPa. (3) Fracture toughness on high hardness is same but on low hardness, inferior.