Wear Resistance of Two Types of Hard-facing Cored Welding Wire

The microstructure and wear resistance of the overlaying welding metal of two new types of hardfacing flux-cored wire HDY704 and HDY502 were studied.Wear resistance of the overlaying welding metal was analyzed before and after heat treatment.The microstructure of the welding metal of HDY704 and HDY502 was martensite and residual austenite.Postweld heat treatment increased wear resistance.The hardness of the overlaying welding metal of HDY502 was increased by 10 HRC,which was caused by the disperse precipitation of carbides.The hardness of the overlaying welding metal of HDY704 remained constant with no disperse precipitation of carbides.The mechanism of wear resistance of the hardfacing overlaying welding metal was cutting damage of sand grains pressed into base metal by vertical stress component in the direction of moving orientation.