送粉量对垂直激光熔覆粉末流场的影响  

Effect of Powder Feed Rate on the Powder Flow Field of Vertical Laser Cladding

作　　者：范红丽 刘玉兵 王治文 张钊 韩日宏 郑明军[1] 齐海波[1,3] FAN Hongli;LIU Yubing;WANG Zhiwen;ZHANG Zhao;HAN Rihong;ZHENG Mingjun;QI Haibo(Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Shijiazhuang College of Applied Technology,Shijiazhuang 050800,China;Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment,Shijiazhuang 050043,China)

机构地区：[1]石家庄铁道大学,石家庄050043 [2]石家庄职业技术学院,石家庄050800 [3]河北省交通工程与环境协同发展新材料重点实验室,石家庄050043

出　　处：《表面技术》2025年第3期142-151,共10页Surface Technology

基　　金：河北省自然科学基金(E2023210011,E2022210043)。

摘　　要：目的激光熔覆头与工作面和水平面均垂直是现有激光熔覆粉末输送的主要研究工况,研究垂直激光熔覆粉末流场可以弥补具有倾斜复杂表面特征、不可移动、不可转动的金属零部件修复的理论空缺,拓展增材制造金属零部件修复应用领域。方法首先构建垂直激光熔覆四路同轴送粉三维气粉耦合模型,基于粉末汇聚焦点和气体流场分布确定基板工作高度和载气流量,然后探究最大粉末浓度、粉斑直径和模拟偏移量随送粉量变化的规律,最后采用单道激光熔覆实验验证模型的准确性,并实现熔覆形貌的预测。结果在垂直激光熔覆下,随着送粉量的增大,粉末汇聚焦点变化不明显,均在距离喷嘴16 mm处;最大粉末浓度由9.8 kg/m3逐渐提升至19.2 kg/m3;模拟偏移量由0.23 mm逐渐提高至0.62 mm;粉斑直径在送粉电压为12~16V时从2.8mm缓慢增至3.2mm,在16~20V时从3.2急剧增至4.3mm;最大粉末浓度、粉斑直径、模拟偏移量与单道激光熔覆层高、层宽、偏移量线性呈正相关,数值模拟预测值与熔覆实验测量值之间的平均相对误差分别为2.15%、1.67%、3.05%。结论在垂直激光熔覆时,送粉量对粉末流场的影响显著,最大粉末浓度、模拟偏移量和粉斑直径均随着送粉量的增大而增大;垂直激光熔覆粉末流场模型准确可靠,可对熔覆形貌进行准确预测。该研究成果可为垂直激光熔覆工艺参数的选取及优化提供理论指导。Laser cladding technology,as an advanced surface modification technology,is characterized by a small heat-affected zone,low dilution rate,and fast repair speed,which has become the main way of repairing and remanufacturing important metal parts.The main research condition for the existing laser cladding powder conveying reveals that the laser cladding head is perpendicular to both the working surface and the horizontal plane.The research on the powder flow field of vertical laser cladding can make up the theoretical gap in the repair of immovable and non-rotatable metal components with tilted and complex surface features and expand the application of metal component repair in additive manufacturing.Firstly,the three-dimensional gas-powder coupling model of four-channel coaxial powder feed for vertical laser melting was constructed to determine the working height of the substrate and the argon gas flow rate of the carrier based on the focus of powder convergence and the distribution of the gas flow field,and then the variation rules of the maximum powder concentration,the diameter of the powder spot and the simulated offset with the amount of powder feed rate were investigated,and finally,a single-pass laser cladding experiment was used to verify the accuracy of the model and predict the cladding morphology.The powder flow field of vertical laser cladding with different powder feed rates was researched,indicating that with the increase of the powder feed rate,the focus of powder convergence did not change significantly,and was at 16 mm from the nozzle.The maximum powder concentration was gradually enhanced from 9.8 kg/m3 to 19.2 kg/m3.The simulated offset progressively increased from 0.23 mm to 0.62 mm.The powder spot diameter slowly increased from 2.8 mm to 3.2 mm at the powder feed voltage of 12 V to 16 V,and sharply increased from 3.2 to 4.3 mm at 16 V to 20 V.The maximum powder concentration,powder spot diameter,and simulated offset were linearly and positively correlated with single-pass laser cladding layer

关 键 词：送粉量 粉末汇聚焦点 最大粉末浓度 粉斑直径 偏移量 模型 

分 类 号：TH16[机械工程—机械制造及自动化]