Study On Preparation And Performance Of Fe-based WC Plasma Cladding Layer

According to the design principle of plasma cladding materials in this article, the Fe-based WC plasma cladding layers with three levels of carbon content(1.0%, 2.8%, 4.0%) and five levels of WC content(0%, 5%, 12%, 20%, 35%) was were prepared during the experiment. Processing property of Fe-based WC mixed powders was discussed based on flow uniformity of powders, macro profile, dilution rate, and homogeneity of microstructure. Microstructure morphology and mechanical property of Fe-based WC plasma cladding layers was studied by OM, SEM, hardness testing and Friction and wear testing. The influence rules of Carbon and WC content on homogeneity of microstructure and property was explored.Within the scope of rated feeding voltage, through measuring, maximum deviation of powder feeding increments was 0.11, which could be considered approximately uniformity, while the feeding voltage changed in range of 10V~20V. Plasma cladding shall be implemented. After optimizing the cladding parameters based on the principle of limit value, cladding layers with good shape and compact structure were obtained, the distribution of dilution rate were 24~35%.The microstructure of plasma cladding layers had a change from hypereutectic microstructure to eutectic microstructure with the decrease of carbon content of Febased al oy. The microstructure of Fe52 plasma cladding layers was mainly eutectic organization and the plasma cladding layers were constituted by primary phase γ(Fe, Cr) and hypereutectic carbide phase(Fe, Cr)7C3 that was hexagonal prism structure with a hole in center. The microstructure of Fe51 plasma cladding layers was mainly hypereutectic and eutectic organization which were constituted by eutectic phase γ(Fe, Cr) and eutectic carbide phase(Fe, Cr)7C3 that presented strip morphology. They were evenly distributed and austenitic which was in the form of binding phase fil ed in the space between the carbides.The hardness of Fe52-based WC plasma cladding layers lowered with the decrease of carbon content of Fe-based alloy and the al oy cladding layers of Fe51 and Fe52 also followed the same rule. With the change of carbon content of Fe-based al oy, the friction coefficient of Fe-based al oy cladding layers had a little change. The wear loss gradually increased with the decrease of carbon content of Fe-based alloy.The hexagonal prism primary carbide(Fe, Cr)7C3 gradually decreased and the carbide that presented strip morphology gradually increased with the increase of tungsten carbide content of Fe-based al oy. A small amount of hard phase(Fe3W3C, Fe6W6 C, W2 C, WC) appeared in the microstructure of plasma cladding layers. Primary carbide and eutectic carbide were evenly distributed which surrounded by austenite. The distribution of extraneous tungsten carbide hard phase presented an irregular state.With the increase of tungsten carbide content of Fe-based al oy, the hardness of Fe52, Fe51 and Fe50 based cladding layer increased in turn. The hardness value of Fe51, Fe50 based cladding layers approached and they were both less than the hardness value of Fe52-based cladding layer. With the change of tungsten carbide content of Fe-based al oy, the friction coefficient of Fe-based al oy cladding layers had a little change. The wear loss gradually decreased with the increase of tungsten carbide content of Fe-based al oy.