目的 通过对比分析1CrMo合金激光熔覆和埋弧堆焊层中Cr元素含量分布，研究激光熔覆替代堆焊技术用于9%Cr钢汽轮机转子轴颈表面改性的可行性。方法 采用与1CrMo合金焊丝成分相同的合金粉末作为激光熔覆材料，利用半导体激光熔覆系统在9%Cr钢表面制备低Cr合金熔覆层。用直读光谱仪、金相显微镜、扫描电镜和显微硬度计等仪器，分析熔覆层中Cr含量分布、熔覆层组织结构和性能，并与堆焊层进行了对比。结果 利用激光熔覆技术成功在9%Cr钢表面制备了不同厚度、无缺陷的1CrMo合金熔覆层，熔覆层组织主要由铁素体和颗粒状碳化物相构成。多层熔覆层硬度在220～250HV0.3之间，与基体硬度接近。激光熔覆可有效减少基体对熔覆层的稀释，熔覆层中Cr含量降低明显，在熔覆层约2 mm厚处的Cr含量已低于2%的工作面Cr含量要求，而堆焊需8 mm左右才能达到相同的降Cr效果，激光熔覆所需熔覆层数明显少于埋弧堆焊法的堆焊层数。结论 与堆焊相比，激光熔覆用于9%Cr钢汽轮机转子轴颈表面改性需熔覆层数少，表面降Cr效率更高。

By comparing and analyzing the content distribution of Cr element in 1CrMo alloy laser cladding and submerged arc surfacing, the feasibility of using laser cladding instead of surfacing to modify the surface of rotor journal of 9%Cr steam turbine was studied. The low Cr alloy cladding layer was prepared on the surface of 9%Cr steel by using the semiconductor laser cladding system. Cr content distribution, microstructure and properties of cladding layer were analyzed by direct reading spectrometer, metallographic microscope, scanning electron microscope and micro-hardness tester.1CrMo alloy cladding layers with different thickness and no defects were successfully prepared on the surface of 9%Cr steel by laser cladding technology. The hardness of multi-layer cladding layer is between 220~250HV0.3, which is close to the hardness of matrix. Laser cladding can effectively reduce the dilution matrix of cladding layer, the cladding layer of Cr content reduce obviously, about 2 mm thickness of cladding layer of Cr content is less than 2wt.% of the working face Cr content requirements, and surfacing to 8 mm to achieve the same effect of Cr, laser cladding layers significantly less than the required submerged arc welding method of surfacing welding layer. Compared with the surfacing welding, less cladding layer is needed for the surface modification of the rotor journal of 9%Cr steam turbine.