Microstructure of Ni60/graphite/MoS2composite layer on surface of 304 stainless steel by laser cladding

作者：Feng Ai Xin; Lü Yu Wen; Wang Shu Xin; Xue Wei; Pei Shao Hu; Zhang Zheng Gang; Cao Yu Peng; Li Feng Ping

来源：Transactions of Materials and Heat Treatment, 2015, 36(4): 189-194.

• 304 stainless steel
• Cellular dendrites
• Columnar dendrites
• Composite layer
• Composite powders
• Equiaxed dendrite
• Microhardness tests
• Stem surfaces

Based on the consideration that the reheat double valve stem with CoCrW coating by acetylene gas welding used in nuclear power plant failures to meet the requiments of 60-year service time, compose layers of Ni60/graphite/MoS2on the 304 stainless steel stem surface were prepared by laser cladding using different formulation of the alloy powders. Microstructure, phase composition and microhardness of the clad layers were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness test. The results show that there are flat crystal, cellular dendrite, columnar dendrites and equiaxed dendrites successively distributed from bottom to top of sample C2, and the average hardness of the sample C2 reaches the maximum value of about 990 HV0.3. As the laser power increases, the fluctuation range of the hardness of the clad coating gets smaller and the distribution of hard phases is more uniform.

• 出版日期2015