Effects of Normalizing Temperature on Microstructure and Properties of Surfacing Layer on NM360 Wear-Resistant Steel

NM360 wear resistant steel plates were repaired by surfacing with D507MoNb welding rod, fellowed by normalizing at different temperatures. The microstructure, hardness, impact toughness and wear resistance of the surfacing layers after treatment were studied. The results show that the microstructure of surfacing layer before normalizing was martensite and carbide. The microstructure of surfacing layer after normalizing at different temperatures was ferrite, pearlite and carbide, and became coarser with the increase of normalizing temperature. Widmanstatten structure was observed in the microstructure at normalizing temperature of 1 050 ℃. And the hardness, impact toughness and wear resistance of surfacing layers decreased with the increase of normalizing temperature. The surfacing layer after normalizing at 900 ℃ had the best comprehensive performance.