APPLICATION OF THERMALLY SPRAYED WC CERMET COATING ON STEEL SUBSTRATE

Thermally sprayed WC-Cr-Ni cermet coating was formed onto the blasted substrate or ground substrate by means of the conventional high velocity oxy- fuel flame spraying (HVOF) as well as the high energy type flame spraying (Hi- HVOF). The substrate material was t hermally refined steel and carburized hardened steel. The WC cermet coated st eel roller was mated with the uncoated carburized hardened steel roller. As a result, it was found that cermet coating on the blasted substrate gener ally exhibits a higher durability compared with that on the ground subs trate and coating formed by HVOF shows a higher durability than that fo rmed by Hi-HVOF with the coating thickness up to 200 μm in the case of thermally refined steel substrate. It was also found that cermet coating exhibits a long life with the coating thickness of 400 μm in the case of thermally refined steel substrate and durability or life to flaking of the coating is not influenc ed by the spraying method. In addition, depending on the blasted substr ate or ground substrate, significant differences in the properties of cerm et coating were found