激光熔覆Ni30WC合金粉末修补42CrMo钢的研究

Repair of 42CrMo Steel by Laser Cladding Ni30WC Alloy Powder

作为高速列车车轴常用的原材料,42CrMo车轴钢在工作中,常因发生疲劳、拉伤断裂、局部磨损等问题而影响使用.为了延长工件使用寿命,在实验中利用激光熔覆技术修复其磨损失效区域,在功率850W,扫描速度8 mm/s的条件下,对车轴钢42CrMo熔覆Ni30WC镍基粉末,制备出与基体结合牢固的熔覆涂层.利用显微镜(OM),扫描电镜(SEM)观察涂层组织形貌,利用X射线衍射仪(XRD)分析涂层物相组成,使用显微硬度仪测量涂层硬度.结果表明:在熔覆层中,主要形成WC﹑W2C﹑(Cr,Ni)和Ni C等物相,涂层与基体结合牢固,但存在明显的裂纹,孔洞等缺陷.涂层硬度显著提高,是基体硬度的3倍以上.

Aiming at local wear of 42CrMo high-speed train axle, laser cladding technology is used to repair the wear area. With the laser power of 850 W at scanning speed of 8 mm/s, Ni30WC nickel powder was laser cladded on 42CrMo substrate. The microstructure of the coating was observed by microscope （OM）, scanning electron microscope （SEM）, the phase composition of the coating was analyzed by XRD, and the hardness of coating was measured by the microhardness tester. The results show that WC, W2C, （Cr, Ni） and NiC are mainly formed in the cladding layer, and the coating and the substrate are firmly combined. Howerver, obvious defects such as cracks and holes are observed. The hardness of the coating is increased significantly, which is more than 3 times of that hardness of the substrate.