Microstructure and Wear/corrosion Resistance of Stainless Steel Laser-alloyed with Mn+W2C, Mn+NiWC and Mn plus SiC

In-situ formed high Mn steel coating reinforced by carbides was formed by laser surface alloying (LSA). Laser alloyed layers on 1Cr18Ni9Ti steel with Mn+W2C (specimen A), Mn+NiWC (specimen B) and Mn+SiC (specimen C) powders were fabricated to improve the wear and corrosion behavior of 1Cr18Ni9Ti steel blades in high speed mixers. Microstructure evolution, phases, element distribution, microhardness, wear and corrosion behavior of the laser alloyed layers were investigated. Results indicated that high Mn steel matrix composites with undissolved W2C, WC and other in-situ formed carbides were formed by LSA with Mn+W2C and Mn+NiWC while SiC totally dissolved into the high Mn matrix when adding Mn+SiC. Ni as the binding phase in Ni-WC powder decreased the crack sensitivity of the alloyed layer as compared with the addition of W2C powder. An improvement in average microhardness was achieved in the matrix in specimen A, B and C, with the value of 615, 602 and 277 HV0.5, while that of the substrate was 212 HV0.5. The increase of microhardness, wear and corrosion resistance is highly corelated to microstructure, formed phases, type and content of carbides, micro-hardness and toughness of the alloyed layers.