Unraveling the Influence of Static Magnetic Field on Carbide Precipitation and Mechanical Properties in Large-Scale H13 Hot Work Die Steel

Abstract

In order to evaluate the potential application advantages of static magnetic field on the development of electroslag remelted large-scale H13 steel technology, the carbides, inclusions, solute segregation and mechanical property of H13 steel were analyzed. The results demonstrated that the implementation of axial static magnetic field (ASMF), the area fraction and size of carbides decreased, and the segregation rate of the elements (C, Mo, V and Cr) decreased. The reason is that the application of ASMF could shorter the local solidification time, decrease the dendrite spacing, alleviate the degree of interdendritic segregation, which limits the time and space for the generation and further growth of carbides. After ASMF was applied, there were lesser and smaller inclusions in H13 steel. Smaller droplet and shallower metal pool are the consequence of utilizing ASMF, which improves the kinetic conditions and removal process that inclusions migration to the slag-metal interfaces. Moreover, samples after forged annealing showed that the average grain size of H13 steel decreased when ASMF was applied, which significantly enhances the mechanical properties. In the absence of ASMF, the product of strength and elongation was 22,599 MPa pct. After applying 60 mT ASMF, the product of strength and elongation increased to 28,770 MPa pct.