Carbides Modification and Mechanical Properties Enhancement of Cr12MoV Die Steel by Magnetically Controlled Electroslag Remelting

The effects of an axial static magnetic field (ASMF) on the carbides and mechanical properties of electroslag-remelted (ESR) Cr12MoV die steel were investigated. The superimposition of a 30 mT ASMF induced unidirectional rotation in the molten slag pool, resulting in a more uniform temperature distribution at the front of the dendrite solid–liquid interface. The size of the grains and carbides in the ESR Cr12MoV steel ingot became smaller. The sulfur content of the ingots decreased and the mechanical properties (hardness and impact energy) increased after applying the ASMF. A new mechanism was proposed that the unidirectional flow was mainly due to the coupled thermoelectric magnetic force induced in the melt between dendrites, which promoted the refinement of grains and carbides, as well as the desulfurization process, thereby resulting in the enhanced mechanical properties of the Cr12MoV die steel.