WEAR AND CORROSION CHARACTERISTICS OF SILICON CARBIDE SURFACE MODIFIED MILD STEEL

Abstract

The wear and corrosion characteristics of silicon carbide (SiC) modified mild steel surface have been studied.  SiC was deposited on mild steel using gas metal arc melting under varying process parameters. Microstructural analysis using optical microscopy indicated the formation of SiC reinforced dendritic structure in the substrate with varying degree of dilution relative to specific process parameter. The improvement obtained in the wear behaviour of the surface modified substrate was attributed to its higher hardness which was influenced by the formation of SiC reinforced dendritic structure in the substrate. Similarly, the corrosion behaviour of the surface modified substrate analyzed using gravimetric analysis and linear polarisation improved across the three media considered. In each of these media, the improvement in corrosion rate peaked at 29%, 33% and 35% in 0.5MHCl, 0.5MNaOH and 0.7MNaCl, respectively, at heat input of about 1.3 kJ/mm. This heat input corresponds to a melting current of 250 A and electrode traverse speed of 5 mm/sec. The improvement obtained in both the wear and corrosion resistances of the surface modified mild steel suggests that low-cost gas metal arc melting technique which is conventionally used for welding can be readily adapted for surface modification as an alternative to the capital intensive laser melting technique.