目的 采用等离子熔覆技术在Q235钢表面制备Fe-Cr-C合金熔覆层，提高基材表面的硬度和耐磨性。方法 通过正交试验确定最佳工艺参数，用SEM、EDS、XRD分析熔覆层的组织结构和物相，用显微硬度计和摩擦磨损试验机测试熔覆层的硬度和耐磨性。结果 工作电流和送粉速度对等离子熔覆层的硬度和磨损量的综合影响最为显著，最佳工艺参数为：工作电流110 A，扫描速度110 mm/min，送粉速度6 r/min，搭接率40%，离子气流量1 L/h。熔覆层硬质相为(Cr,Fe)7C3，其余物相为γ-Fe、(Fe,Cr)、(Fe,Ni)、(Fe,C)、(Fe,Ni)23C6、Cr7C3、Ni3Si、Fe3Mo、Fe2Nb。最优参数试样熔覆层的平均显微硬度为545.1HV0.5，比Q235钢基体的硬度高3倍左右。经过5 h摩擦磨损试验后，其总磨损量为0.25 g，比基体磨损量减少约2/3；磨损体积为45.09 mm3，约为基体磨损体积的1/3；磨损率为1.22×10-4 mm3/(N?m)，约为基体磨损率的1/3；摩擦系数为0.23，约为基体摩擦系数的1/2。结论 在Q235钢基体表面采用等离子熔覆技术制备出Fe-Cr-C合金熔覆层，其硬度和耐磨性能得到显著提升。

The work aims to improve the hardness and wear resistance of substrate surface by preparing Fe-Cr-C alloy coating on Q235 steel with plasma cladding. The best process parameters were determined by orthogonal test, the microstructure and phase composition of the cladding coating were investigated by SEM, EDS and XRD, and the microhardness and the wear resistance were tested by hardness micrometer and friction wear testing machine. The working current and feeding speed had the most significant effect on the hardness and wear mass of cladding coating. The optimum combination of process parameters included working current of 110 A, scanning speed of 110 mm/min, powder feeding speed of 6 r/min, overlap rate of 40% and ionic gas flow of 1.0 L/h. In addition, the hard phase of the cladding coating was (Cr,Fe)7C3 and the remaining included γ-Fe, (Fe,Cr), (Fe,Ni), (Fe,C), (Fe,Ni)23C6, Cr7C3, Ni3Si, Fe3Mo and Fe2Nb. The average microhardness of the specimen with the optimum process parameters reached 545.1HV0.5, which was enhanced 3 times over that of the Q235 substrate. After 5 hours of friction and wear test, the wear mass was 0.25 g, 2/3 less than that of the substrate. The wear volume was 45.09 mm3, about 1/3 of the substrate. The wear rate was 1.22×10-4 mm3/(N?m), about 1/3 of the substrate. The coefficient of friction was 0.23, about 1/2 of the substrate. The hardness and wear resistance of the Fe-Cr-C alloy coating prepared on Q235 steel by plasma cladding technology are improved obviously.