针对激光熔覆专用粉末的问题, 微调材料配比, 采用真空气雾化的方法制备了激光熔覆用Fe55合金粉末。研究了不同雾化气体压力、导流管直径对粉末粒度分布的影响; 在最佳工艺参数下, 对粉末的成分、杂质含量进行了测试; 利用扫描电镜(SEM)、X射线衍射仪(XRD)对粉末形貌、相结构进行了观察与分析; 采用霍尔流速计测试粉末的流动性; 最后, 将粉末在42CrMo基体上进行激光熔覆试验, 并对涂层的硬度进行测试。结果表明, 雾化气体压力在3.5 MPa, 导流管直径6.0 mm时, 所得粉末主要分布在10~300 μm之间; 粉末具有较低的杂质含量, 其中氧含量274 ppm, 氮296 ppm, 硫含量157 ppm; 粉末形貌大多呈现为球形、类球形结构, 卫星球较少, 粉末物相结构主要由α-Fe、M-(FeCr)固溶体相组成; 粉末流动性为17 s/50 g, 表现出良好的激光熔覆性, 涂层的硬度在HRC 54.5~56.8之间。

Focus on the question of specific powers for laser cladding, adjusted the ratio of material, The Fe55 alloy powder for laser cladding was prepared by vacuum gas atomization(VIGA). The influence of different atomized gas pressure and diameter of metal delivery tube on powder particle size distribution was studied. Under the optimum technological parameters, the composition and impurity content of the powder were tested. The morphology and phase structure of powder were observed and analyzed by SEM and XRD. The flowability of powder was tested by hall flow meter. Finally, the powder was subjected to laser cladding tests on 42CrMo substrate, and the hardness of the cladding coating was tested. The results show that when the atomizing gas pressure is 4.0 kPa and the diameter of the metal delivery tube is 6.0 mm, the powder particle size is mainly distributed between 80~600 mesh. The powder has lower impurity content, of which the oxygen content is 274 PPM, the nitrogen content is 296 PPM, and the sulfur content is 157 PPM. Powder morphology is mostly spherical or nearly spherical, with fewer satellite spheres. The powder phase structure is mainly composed of α-Fe、M-(FeCr) solid solution. The flowability of powder is 17 s/50 g. The powder exhibits good laser cladding properties, and the hardness of the cladding coating is between HRC 54.5~57.6.