Distribution characteristic and precipitation behavior of primary carbides in industrial grade AISI M35 high-speed steel produced by electroslag remelting

The characteristic of primary carbides in industrial grade M35 high-speed steel was analyzed systematically using an association of scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and energy dispersive spectrometer (ESD), and the precipitation behavior of various carbides was discussed by combining the thermodynamic calculation and the microsegregation model. The results indicate that the size of network carbides at the center area is larger than that at the edge area in the electroslag remelting (ESR) ingot. The area fraction and average width of carbides increase gradually with the increase of height, and the values located in the top are 6.79% and 4.83 μm, respectively. The lamellar M 2 C carbide, fishbone M 6 C carbide and blocky MC carbide compose the network structure, also there are several independently distributed cerebriform carbides. Compared to M 6 C carbide, the Mo/W ratio and the contents of V and C in M 2 C carbide are higher, and MC carbide is prominently characterized by the highest V content. Simultaneously, the precipitation of Fe-rich M 6 C carbide that occurs in the top is closely related to the low cooling rate besides the influence of alloying elements. The current reduction operation can genetically promote a reduction of 0.75% in the average area fraction and 0.04 μm in the average size of carbides in the forged steels, which is beneficial for reducing and homogenizing primary carbides in the ESR ingot.