Nodular cast iron is famous for its poor weldability owing to the great tendency of chilled structure in the interface zone during welding and cladding process. In order to eliminate chilled structure, laser cladding of nodular cast iron using powder pre-placed method was successfully carried out. The dilution ratio could be reduced obviously, and the chilled structure also could be eliminated. The microstructure was determined and the microhardness characteristics were researched. Optical microscope (OM) and Scanning electron microscopy (SEM) were used to identify the microstructure. Chemical composition was carried out using Energy dispersive spectrometer (EDS). The results also showed that the average microhardness of the interface zone decreased obviously when the chilled structure was eliminated.

球墨铸铁由于焊接和熔覆过程中界面区域的冷态组织趋势大而以其可焊接性差而闻名。为了消除冷硬组织，成功地采用粉末预放置法对球墨铸铁进行了激光熔覆。可以明显降低稀释比，也可以消除冷却结构。确定了显微组织并研究了显微硬度特性。使用光学显微镜（OM）和扫描电子显微镜（SEM）鉴定微观结构。化学成分使用能谱仪（EDS）进行。结果还表明，消除冷却结构后，界面区的平均显微硬度明显降低。