Abstract
Hardfacing by Stellite is extensively employed in many engineering applications for enhancing high temperature wear, oxidation and corrosion resistance of austenitic stainless steel components. These overlaid components, because of large difference in thermo-physical and mechanical properties between clad and substrate, are largely prone to cracking. Cracking resistance of Stellite 6 clad austenitic stainless steel components can be greatly enhanced by providing smooth composition gradient across substrate-clad interface. This article presents development of graded overlay of Stellite 6 on AISI 304 stainless steel substrate using 2.5 kW continuous wave CO 2 laser and their comparison with directly Stellite 6 clad AISI 304 stainless steel specimens. Graded overlaying of Stellite 6 effected significant reduction in microhardness gradient across substrate-clad interface with respect to that of directly Stellite 6 clad specimens. Thermal cycling tests, performed on laser-cladded specimens, demonstrated superior cracking resistance of graded overlaid specimens over that of directly Stellite 6 clad austenitic stainless steel specimens.