Microstructure and Tribological Properties of PTA Deposited Stellite 12 Coating on Steel Substrate

Abstract

The present work studies microstructure and wear resistance of Stellite 12 alloy coating deposited on quenched and tempered AISI 4140 steel substrate using plasma transferred arc (PTA) hardfacing method. The X-ray diffraction, scanning electron microscopy (SEM) micrographs and energy-dispersive X-ray (EDX) analysis indicated that Stellite12 mainly consists of solid solution phase (α-Co, e-Co), chromium-rich carbides (Cr7C3, Cr23C6) and tungsten-containing compounds. The wear properties of PTA hardfaced stellite12 comparing with AISI 4140 steel at room temperature (RT) were investigated by using the ball-on-disc type tribotester. It has been found that the Stellite12 hardfacing coating exhibits superior wear resistance than substrate during dry sliding wear test at RT.