激光重熔对镍基碳化钨涂层性能的影响

Effects of Laser Remelting on Properties of Ni-based WC Coating

为了进一步提高自熔性镍基碳化钨涂层综合性能,利用IPG光纤激光器YLR-3000激光加工系统进行重熔实验,激光重熔工艺参数为:离焦量3mm、扫描速度2mm/s、送粉电压8V和激光功率1200W,使用洛氏硬度计、蔡司高级金相显微镜和显微硬度计分析激光重熔后熔覆层硬度及组织的影响。结果表明:通过激光重熔后,熔覆层组织致密均匀,熔覆层中上部分组织晶粒细小,晶粒得到了细化,沿熔覆层与基体交界处晶粒向外延生且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;熔覆层硬度得到提高,显微硬度分布均匀并且与基体相比提高约3倍。激光重熔可以改善镍基碳化钨涂层的微观形貌,提高其机械性能。优化工艺参数:激光功率1300W、重熔功率1200W、扫描速度2mm/s、送粉电压8V。

Objective to further improve comprehensive performance of self-fluxing Ni-based WC coating,using IPG fiber laser YLR-3000 laser processing system for laser remelting experiment,process parameters of laser remelting is that defocus amount（3mm）、scan speed（2mm/s）、powder feeding voltage（8V） and laser power（1200W）,using rockwell hardness、advanced microscope and Micro hardness tester to analyze that effects of laser remelting on hardness and organizations of coating. The results show that organization of cladding layer becomes dense and uniform,and the upper part of the organization of cladding grain becomes a fine size,between cladding layer and the substrate,grains begin to grow outward and organization presents columnar crystals and equiaxed and good organizational performance. Metallurgical bond of the substrate and cladding layer is strong. Hardness of the cladding layer is improved,uniform distribution of microhardness and the average hardness of the cladding layer is about 3 times as that of the substrate. Laser remelting nickel-WC coating can improve the morphology and optimization of process parameters is that laser power（1200W）、remelting power（1200W）、scan speed（2mm/s）、powder feeding voltage（8V）.