Surface modifications to grooved SM45C mold steel plates using large-electron-beam polishing

In this study, a recently developed electron-beam polishing process was adopted to improve the surface quality of grooved SM45C mold steel plates. A large electron beam with a maximum diameter of 60 mm was used to instantly melt and evaporate the metal surface in a few microseconds to observe its effect on surface hardness, surface roughness, water repellency, and microstructure variation. The effects of the groove depth and width on the plate were also experimentally observed. The surface polished by the electron beam became smoother, but as the groove depth increased, the effect of the large-electron-beam polishing decreased. Although the surface hardness dropped by approximately 20% on the re-solidified layer, the contact angle increased after the electron-beam irradiation. The microstructure variation on the polished surface was also examined.