Effect of Annealing Temperature on Microstructure and Properties of Wear-Resistant Steel NM360 Hardfacing Layer

NM360 wear resistant steel plate was repaired by hardfacing with D507MoNb electrode and then annealed at different temperature(200℃,400℃ and 600℃) after welding.The effects of annealing temperature on the microstructure,hardness,impact toughness and wear resistance of the hardfacing layer were studied.The results show that the microstructure of the hardfacing layer before annealing was martensite and carbide,after annealing at 200℃,400℃ and 600℃,the microstructure was tempered martensite,tempered troostite and tempered sorbite respectively.With the increase of annealing temperature,the hardness and wear resistance of the hardfacing layer decreased,but the impact toughness increased.The hardfacing layer annealed at 200℃ had the best wear resistance,and its relative wear resistance was 1.327 times of the base metal.