316L stainless steel repaired layers by weld surfacing and laser cladding on a 27SiMn steel: A comparative study of microstructures, corrosion, hardness and wear performances

In this study, 316L stainless steel repaired layers were fabricated on a 27SiMn steel substrate using weld surfacing and laser cladding, respectively. The microstructures of repaired layers were subjected to dedicated characterizations using X-ray diffraction, electron backscatter diffraction and energy dispersive spectrometry, with their surface properties (corrosion and wear performances) measured and correlated with the revealed microstructure features. Both the weld-surfacing and the laser-cladding repaired layers (RLs) are found to be mainly comprised of columnar-grained γ-Fe phase, with their average grain widths measured as 17.0 ± 20 μm and 15.3 ± 13.7 μm, respectively. Between their RLs and substrates, an unreported transition layer (∼50 μm in thickness) jointly composed of γ-Fe and α-Fe is identified. After surface property tests, the RL fabricated by the laser cladding shows superior corrosion and wear resistance to that of the weld surfacing. Comprehensive analyses based on their microstructure features suggest that the better performance of the laser-cladding RL can be ascribed to the laser-induced ultrafast cooling that allows denser and finer grain structures to be produced.