激光熔覆工艺参数对高速钢涂层性能的影响

通过激光熔覆技术，在316L不锈钢表面制备了高速钢涂层。研究了送粉速度和扫描间距(搭接率)对熔覆层性能的影响。结果表明，在送粉速度0.4 r/min、扫描间距0.9 mm时，熔覆层性能较佳。熔覆层表面平滑，无球化缺陷，与基体之间冶金结合良好; 熔覆层内部组织紧密，无气孔和浮渣等缺陷。熔覆层组织结构从下至上依次为平面晶、柱状晶和等轴晶。熔覆层由α-Fe和碳化物组成，且碳化物分布均匀，无明显偏析。熔覆层平均硬度为基体的3.68倍。熔覆层动摩擦系数分布曲线波动小，明显低于基体动摩擦系数。

Effect of Process Parameters of Laser Cladding on High-Speed Steel Coating

By using laser cladding technology, a high-speed steel coating was prepared on the surface of 316L stainless steel, and the influence of powder feeding rate and scanning distance (lap ratio) on the performance of the cladding layer was investigated. It is found that the cladding layer can present a better performance with the powder feeding rate of 0.4 r/min and the scanning distance of 0.9 mm. The surface of the cladding layer is smooth without spheroidizing defect, and there is a low dilution zone between the cladding layer and the matrix, showing good metallurgical bonding. The cladding layer has a compact internal structure without defects of pores and scum, in which there are planar grains, columnar grains and equiaxed grains in turn from the bottom to the top. The cladding layer is composed of α-Fe and carbides, and the carbides are uniformly distributed without obvious segregation. The average hardness of the cladding layer is 3.68 times that of the substrate. The distribution curve of the dynamic friction coefficient of the cladding layer shows little fluctuation, which is obviously less than that of the matrix.