Effect of laser path overlap on surface roughness and hardness of layer in laser cladding

A Ni–Cr–Si–B alloy coating was produced on a type 304 stainless steel plate by laser cladding. A diode laser with a flat-top beam profile was used in this experiment. The effects of focused laser spot overlap on surface roughness (Ra) and Vickers hardness were investigated. Ra and the Vickers hardness of the cladding layers decreased as the overlap ratio increased. Cladding layers that maintained a hardness comparable to that of the source powder material were produced at overlap ratios of < 70%.