SiO 2 particle erosion of spheroidal graphite cast iron after surface remelting by the plasma transferred arc process

Abstract

Two spheroidal graphite cast irons of the same composition (Fe 3.54 wt.%-C 2.48 wt.%-Si) and different graphite nodule counts were surface hardened by plasma transferred arc surface remelting. They were then eroded by angular SiO 2 particles (∼295 μm grit size) under two average particle velocities including ∼36 and ∼66 m s −1. According to the results, the presence of eutectic Fe 3C in the remelted layer can improve the erosion resistance at oblique impact by increasing the flow resistance; but the eutectic Fe 3C particles are also subjected to brittle cracking under large-angle impact. Hence, while oblique impact shows larger improvement of the erosion resistance with increasing content of eutectic Fe 3C, large-angle impact indicates that the improvement can be achieved only when the content of eutectic Fe 3C and the particle velocity are properly restricted. Brittleness effect of eutectic Fe 3C also causes the maximum erosion rate to occur at larger impact angle for the remelted layer of more eutectic Fe 3C.