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目的 提高45 #钢的表面性能. 方法 利用IPG光纤激光加工系统,采用不同的工艺参数在45 #钢表面激光熔覆自熔性镍基碳化钨粉末,对熔覆层的宏观表面(平整度、表面硬度、裂纹情况)及金相组织、显微硬度分布进行对比分析. 结果 在激光功率为1200 W、扫描速度为2 mm/s、送粉电压为7 V时,获得的熔覆层宏观表面相对平整光滑,平均洛氏硬度约是基体的2. 5倍. 由微观组织分析得知,熔覆层及界面处无裂纹、气孔等缺陷,熔覆层中上部组织晶粒细小,沿熔覆层与基体交界处向外,晶粒呈现柱状晶及等轴晶,组织性能良好,基体与熔覆层间冶金结合比较牢固. 熔覆层显微硬度分布比较均匀,并且与基体相比提高了约1. 5倍. 结论 45#钢表面机械性能得到提升,在其表面激光熔覆自熔性镍基碳化钨粉末具有可行性和研究价值.

Objective To improve the surface properties of 45# steel. Methods Using IPG fiber laser YLR-3000 Laser Proces-sing System, laser cladding of self-fluxing Ni-based WC Powders was conducted on the surface of 45# steel using different process parameters. Comparative analysis was conducted on the macroscopic surface ( Flatness, surface hardness, cracks) , metallurgical structure and distribution of microhardness of the cladding layer. Results When the laser power was 1200 W, scanning speed was 2 mm/s, and powder feeding voltage was 7 V, the cladding layer had relatively smooth macro surface, and the average Rockwell hardness of the cladding layer was about 2. 5 times that of the matrix. The microstructure analysis showed that there were no defects such as cracks and holes in the cladding layer and the interface, the middle and upper part of the cladding layer had fine grains, the grains were dendritic and equiaxed along the interface of the cladding layer and the substrate, the structural performance was good, and the metallurgical bonding between the cladding layer and the substrate was relatively strong. The microhardness distribu- tion of the cladding layer was relatively even, and increased by about 1. 5 times as compared to the substrate. Conclusion The me-chanical properties of 45# steel surface were improved. Laser cladding of self-fluxing nickel-based tungsten carbide powder on its surface has therefore feasibility and research value.