Friction and Wear Characteristics of Plasma Surfacing Stellite Alloys at Elevated Temperatures

Stellite 1 and Stellite F coatings were fabricated on the substrate of valve steel by plasma surfacing. Metallographic structure, phase composition and hardness were analyzed. The tribological properties of the two kinds of the welding coatings were investigated on a MMU-10G friction and wear tester at elevated temperatures. Results indicate that at elevated temperatures, with the rise of temperature, the friction coefficient of both coatings increased whereas the wear volume decreased. At 400 , Stellite 1 and Stellite F coatings were seriously damaged due to the appearance of fatigue cracks and wide furrows. The main wear mechanisms of both the coatings were fatigue flake and abrasive wear at 500 and 600 . The formation of oxide film and the decreasing hardness of the counterparts resulted in less wear and the central area of wear trace becoming narrower. However, wear debris were accumulated and crushed on both sides of the wear trace, leading to a severe adhesive wear which is related to the large friction coefficient.