Effect of the Melting Rate of ESR on the Microstructure and Impact Properties of H13 Steel

Double electrode series technology was adopted to electroslag remelting for φ385mm diameter ingot of H13 steel,and effect of the quicker melting rate and slower melting rate on the as-cast structure of ESR ingot,annealing microstructure,banding segregation and impact properties of forging products was investigated.The results show that the secondary dendrite arm spacing of ingot increases and primary carbides and others interdendritic microsegregation are more serious by the quicker melting rate than that by slower melting rate.The annealing microstructure are more uniform,the banding segregation alleviates,the transversal impact toughness is improved obviously of the forging products by the slower melting rate than that of the quicker melting rate and come up to the standard of high-quality steel H13 level stipulated by NADCA207-90.