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研究了激光送粉熔覆WC Co硬质合金的气孔问题。结果表明 ,激光熔覆WC Co形成气孔的倾向较大 ,细粉熔覆层的气孔率比粗粉高 ,多道叠加的气孔率比单道高。熔覆层组织为未熔化的WC颗粒、鱼骨状枝晶和Co固溶体基体。熔覆层含有WC、Co、FeW3C、Fe2 W ,CW3,Co3O4 等相。激光熔覆WC Co出现气孔的主要原因归结于高温熔池中的氧与碳反应形成CO或CO2 气体。在WC Co中添加一定量的金属还原剂Ti后 ,Ti能还原熔池中的氧化物 ,阻止O与C的化合 ,抑制CO或CO2 气体的生成 ,从而减少气孔率甚至消除气孔。加Ti后 ,熔覆层中的Co3O4 相消失而出现了Ti2 O和Co6 W6 C相。
The stomatal problem of laser cladding WC Co cemented carbide was studied. The results show that laser cladding WC Co tends to form stomatal, and the porosity of the powder cladding layer is higher than that of the coarse meal. The cladding was organized into unmelted WC particles, fish bone dendrites and Co solid solution matrix. The cladding layer contains WC, Co, FeW3C, Fe2W, CW3, Co3O4 and other phases. The main reason for laser cladding of WC Co is that the oxygen in the high temperature molten pool reacts with carbon to form CO or CO2 gas. Adding a certain amount of metal reductant Ti in WC Co can reduce the oxides in the molten pool, prevent the combination of O and C, inhibit the generation of CO or CO2 gas, and reduce the porosity and even eliminate the pores. After adding Ti, the Co3O4 phase in the cladding disappears and Ti2 O and Co6 W6 C phases appear.