利用DL-T5000型二氧化碳激光器在QT-500球墨铸铁表面熔覆铁基合金层, 分析了激光熔覆层的显微组织, 测试了其显微硬度及磨损性能。结果表明: 制备的熔覆层组织致密、无裂纹, 与基体形成了良好的冶金结合; 从熔覆层表面到热影响区的组织依次为大量的树枝晶、等轴晶、树枝晶; 熔覆层的硬度较基体的提高了2.5倍, 其磨损量约为基体的1/3, 熔覆层耐磨性能增强的主要原因是铁基合金与元素镍、铬等形成固溶体和碳化物等的强化作用所致。

Laser cladding of Fe-based alloy layer on QT-500 ductile cast iron surface was carried out by DL-T5000 CO2 laser. The microstructure, microhardness and wear resistance of the laser cladding layers were analyzed and tested. The results show that the cladding layers had compact and flawless microstructure that had been integrated metallurgical bonding with substrate. Microstructure of the cladding zone consisted of massive branch crystal, equiax crystal and branch crystal in turn from the surface of cladding layers to heat-affected zone. The microhardness of the layers increased 2.5 times campared with that of the substrate and the abrasion weight was one third of that for the substrate. The reasons of the wear resistance improving were mainly strength due to solid solution formation of elements Ni and Cr to Fe-based alloy and carbides.