The effect of Nb content on microstructure and properties of laser cladding 316L SS coating

316L SS with different Nb content (0.2, 0.5, 1.0, 3.0, 5.0, 7.0 wt%) coatings were fabricated on Q235 steel plate by laser cladding. The addition of Nb made the phase structure of 316L change from FCC to FCC + BCC + Laves phase. With the Nb content increasing, the microhardness of 316L coating increased gradually. The Nb7.0 coating is about 2.0 times as hardness of the substrate. Electrochemical testing showed that Nb 1.0 coating had the best corrosion resistance in 3.5 wt% NaCl solution. Excess Nb will cause corrosion to occur more easily and decrease the corrosion resistance of the coating.