Effect of Parameters on Internal Crack Healing in 30Cr2Ni4MoV Steel for 600-Ton Ultra-Super Ingots

The effect of parameters on internal crack healing in 30Cr2Ni4MoV steel for 600-ton ultra-super ingots was systematically investigated. The results show that the degree of crack healing increases with increasing healing temperature, holding time, reduction ratio, and hot pressure, and with decreasing strain rate. Internal crack healing in 30Cr2Ni4MoV steel should be conducted at less than 1200 °C to avoid grain coarsening. Hot pressure, in the high-temperature elastic zone and perpendicular to the crack faces, not only promotes the rapid crack healing, but also prevents grain coarsening of the matrix.