Microstructure and Properties of CuSn8Ni/ ST37-2G steel Composites Prepared by Laser Cladding

CuSn8Ni alloy powders were deposited on the low carbon steel plate by laser cladding technology to prepare a CuSn8Ni/ST37-2G steel bimetal-lic bearing material. Microstructure, microhardness, and interfacial ele-mental diffusion of the CuSn8Ni laser clad coating were investigated. The optimum process parameters for laser cladding the CuSn8Ni alloy were obtained. The results showed that when the laser power was 1300 W, scanning speed was 8 mm/s and the powder feed speed was 0.5 rpm, the CuSn8Ni laser clad layer had an excellent metallurgical bond with the matrix and had no apparent defects. The laser clad layer had a dendritic microstructure. It mainly consisted of Sn-containing alpha-Cu solid solution and interdendritic (alpha+delta) eutectoid. Cu and Fe elements had significant element diffusion behaviours, and the diffusion distance was about 1 to 2 mu m. The average hardness of the coating was 128.6 HV, twice that of the traditional Cu-Pb bearing material.