Effect Of Process Variables On The Mechanical Properties Of Surface Hardened Mild Steel Quenched In Different Media

Abstract The effect of process variables on the mechanical properties of surface hardened mild steel quenched in water and brine was investigated. The process variables are treatment temperature and soaking time and the mechanical properties studied are impact strength Rockwell hardness ductility and micro-hardness. Pack carburization method of surface hardening was used. Standard tests and analytical methods were used for the research and results obtained showed that impact strength decreased by 82.14 and 96.43 when quenched in water and brine respectively as compared to the control specimen the impact strength of which was 84J. Rockwell hardness increased by 15.09 and 23.27 when quenched in water and brine respectively. Micro-hardness also increased by 120.55 and 45.5when quenched in water and brine respectively while ductility decreased significantly from 12.73 to 3. The process variables investigated affected the mechanical properties as increase in treatment temperature and soaking time increased the surface hardness and decreased the impact strength and ductility of mild steel while micro-hardness and Rockwell hardness increased. Mild steel quenched in water was found to be harder than that quenched in brine.