激光熔覆孔式同轴送粉系统设计及实验研究

Design and experimental study of multi-hole coaxial powder feeding system for laser cladding

为了解决送粉激光熔覆系统中因重力作用发生偏聚及水冷效果差等问题,采用以激光束轴心为中心轴圆周均匀分布送粉孔的方法,没计了一系列孔式同轴送粉喷嘴(主要结构包括激光束通道、保护气体通道、水冷通道、气载送粉通道),从而获得良好的粉末流形态,提高送粉激光熔覆的质量。用该系列喷嘴在竖直(90°),60°,30°和水平(0°)等工况下进行粉末汇集性实验,发现粉末汇集效果良好。通过对Ti和Ni粉末、工具钢和等材料进行熔覆实验,送粉系统输送的粉末稳定、均匀,得到的熔覆样品表面光滑、熔覆层组织均匀,熔覆层与基体呈冶金结合。结果表明,孔式同轴送粉系统较好地满足了激光熔覆对送粉喷嘴的要求,并且能用来进行多种元素粉末的材料合成。所开发的送粉系统适用于材料表面改性和熔覆3维制造。

To solve the problems of unsatisfied water-cooling and deposit deviation induced by gravity during laser cladding, a series of feeding nozzles distributed radially and symmetrically was designed to obtain satisfied powder stream and improve cladding quality （the main structure including laser beam routeway, shielding gas routeway, water-cooling routeway and gas feeding routeway）. It was found that the powder pooling was satisfied during experiments conducted under conditions that the angles between the nozzle and horizontal plane were 90°, 60° , 30 ° and 0° respectively. Some experiments were also conducted adopting powders of Ti, Ni and tool steel respectively. Powders were fed stably and uniformly during experiments. The cladding samples with smooth surface and homogeneous microstructure were metallurgically bonded with the substrate. Experimental results show that the nozzles are satisfactory for powder feeding in laser cladding and can be used for material synthesis of powders. The system is suit for surface modification and 3-D solid fabrication.