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为获得表面高硬度层及冶金结合,分别以铸铁和普通碳钢为基体,以含WC的镍基合金粉末为熔覆材料,采用激光熔覆技术制备了大面积的熔覆层。测试了熔覆层、结合处以及基体的硬度,并采用扫描电镜、能谱仪对熔覆层进行了微观组织分析。结果表明,以铸铁为基体不易制得良好的熔覆层,而以45钢为基体时,在激光功率1200~2000W之间,扫描速度在2 mm/s左右时能获得质量良好的熔覆层。熔覆层表面硬度高达1100 HV以上,熔覆层与基体呈冶金结合,熔覆层无微观裂纹,微观组织分布均匀,磨削平整后熔覆层厚度可达1 mm以上。
In order to obtain the surface high hardness layer and the metallurgical bonding, cast iron and ordinary carbon steel were used as the matrix respectively, and the WC-containing Ni-based alloy powder was used as the cladding material. Large-area cladding layer was prepared by laser cladding. The hardness of the cladding layer, the junction and the matrix were tested. The microstructure of the cladding layer was analyzed by SEM and EDS. The results show that it is not easy to obtain a good cladding layer with cast iron as the substrate. When 45 steel is used as the substrate, a good quality cladding layer can be obtained when the laser power is between 1200 and 2000W and the scanning speed is about 2 mm / s . The surface hardness of the cladding layer is over 1100 HV, the cladding layer is metallurgically bonded with the substrate, the cladding layer has no microscopic cracks, and the microstructure is evenly distributed. The cladding layer thickness after grinding is over 1 mm.