Abstract: The effects of quenching and tempering at different temperatures on the microstructure， strength and wear resistance of NM450 high strength low-alloy wear-resistant steel were studied. The results showed that the lath martensite with a small amount of ferrite structure was obtained for the high-strength low-alloy wear-resistant steel quenched at 840 ℃ and tempered at 200 ℃. The lath martensite was obtained and the martensite matrix contains high-density dislocation， and the residual austenite was distributed between the martensite lath for the steel quenched at 880 ℃-900 ℃ and tempered at 200 ℃.With the increase of quenching temperature， the yield strength of wear-resistan steel NM450（/%：0.20C，0.50Si，2.0Mn，0.20Cr，0.03Als，≤0.015P，≤0.005S）was between 1142 MPa and 1 173 MPa， the tensile strength was between 1 553 MPa and 1 599 MPa， the elongation was between 10.0% and 12.0%. The strengthening mechanism of the test steel was mainly dislocation strengthening and fine grain strengthening and solid solution strengthening. There were a lot of furrows and grinding chips of the steels for abrasive wear， and the wear mechanism was mainly plastic deformation. The strength and wear-resistance proformance was the best for the steel quenched at 880 ℃ and the tempered at 200 ℃.

Key words: Wear-resistant Steel NM 450, Microstructure, Strength, Wear Loss

摘要： 研究了不同温度淬火、低温回火对高强度低合金耐磨钢的组织、强度与耐磨性能的影响规律与机理，结果表明：高强度低合金耐磨钢在840 ℃淬火，200 ℃回火，得到板条马氏体加少量铁素体组织，在880~920 ℃淬火，200 ℃回火，得到板条马氏体，马氏体基体中均含有高密度位错，马氏体板条之间有纳米尺寸条状残余奥氏体。随淬火温度升高，耐磨钢NM450成分质量分数（/%：0.20C，0.50Si，2.0Mn，0.20Cr，0.03Als，≤0.015P，≤0.005S）的屈服强度在1 142~1 173 MPa，抗拉强度在1 553～1 599 MPa，伸长率在10.0%~12.0%。试验钢的强化机理主要是位错强化、细晶强化与固溶强化，试验钢磨损表明有大量的犁沟与磨屑，磨损机理主要是塑性变形。试验钢在880 ℃淬火，200 ℃回火强度与耐磨性能均最佳。

关键词: 耐磨钢NM450, 组织, 强度, 磨损