摘要
目的扩展增材制造在斜面复杂零部件修复领域的应用,弥补倾斜熔覆过程中粉末流动行为研究的空缺。方法采用RSM进行模拟方案设计与数据处理,通过拟合输入参数与输出之间的数学模型,探究送粉电压、气流量、基体倾斜角度对倾斜基体上粉末浓度和粉斑直径的影响规律。结合数值模拟和试验研究对光粉耦合机理进行分析,探究光粉平衡关系对涂层形貌的影响机理。结果粉末颗粒速度随气流量的增加而增大;倾斜基体上最大粉末浓度随气流量的增大而降低,随送粉电压的增大而增高;倾斜基体上的粉斑直径随基体倾斜角度和气流量的增大而增大。以倾斜基体上的粉末浓度最大、倾斜基体上的粉斑直径最小为优化目标,0°、10°、20°、30°倾斜基体上最大粉末浓度模拟值与预测值的误差分别为4.34%、3.61%、5.82%、13.15%,基体上粉斑直径模拟值与预测值的误差分别为2.95%、3.22%、3.57%、4.10%,说明该模型对倾斜基体上最大粉末浓度及粉斑直径的预测精度较高。结论气流量对粉末颗粒速度影响显著,送粉电压、气流量对基体上最大粉末浓度的影响显著,倾斜角度、倾斜角度与气流量的交互项对倾斜基体上的粉斑直径影响显著。研究结果为激光熔覆在斜面零件修复领域应用中基体的布置和工艺参数选取提供了理论指导。
At present,the research on the numerical simulation of powder flow is mainly based on the working ranges of nozzles and flat substrates,which greatly limits the application of laser cladding in repairing inclined substrates.Meanwhile,the existing research on the powder flow field of laser cladding is based on the single factor way.The response surface methodology(RSM)was used to design the simulation scheme and process the data in the work.The mathematical model between the input and output parameters was fitted to explore the effects of powder feeding voltages,gas flow rate and inclination angles of substrates on the powder particle velocity,powder concentration,and powder spot diameter on inclined substrates.The convergence of powders was studied by numerical simulation and experiments to explore the coupling of optical powders and the effects of their balance relationships on coating morphologies.Ni35A powders(with an average particle size of 1×10^(-4)m)were used for simulation and experiments,and 45#steel(40×20×10 mm)was used as the base material in experiments.Powder beam conically converged and then conically diverged from the nozzle outlet in the simulation of the powder flow field.The convergence positions were consistent with actual powder flow fields captured by high-speed cameras,which verified the reliability of the model.Meanwhile,the simulation of the powder flow field was carried out according to the simulation scheme,and the powder-particle velocity increased with the increasing gas flow rate.Maximum powder concentration on inclined substrates decreased with the increasing gas flow rate,but increased with the increasing powder feeding voltage.The powder spot diameter on inclined substrates increased with the increasing inclination angles of substrates and gas flow rate.The simulation results were verified experimentally.When other process parameters were constant,the greater the powder concentration on the substrate was,the greater the cladding area was.When the powder feeding voltage increased from 10 to 26 V,the area of the cladding layer increased accordingly.When the gas flow rate decreased from 30 to 6 NL/min,the area of the cladding layer increased accordingly.When inclined substrate angleθincreased from 0°to 40°,the area of the cladding layer decreased accordingly.The law obtained from the simulation was consistent with that of the experiment.Therefore,the model had important guiding significance for selecting process parameters in the actual cladding process.The model had high prediction accuracy for maximum powder concentration and powder spot diameter on inclined substrates.The optimization objectives included the maximum powder concentration and the minimum powder spot diameter on inclined substrates.The errors between the simulated and predicted values of maximum powder concentration on 0°,10°,20°,and 30°inclined substrates were 4.34%,3.61%,5.82%,and 13.15%,respectively and those of powder spot diameters on the inclined substrates were 2.95%,3.22%,3.57%,and 4.10%,respectively.Optical powder coupling showed that when laser power was constant,the metal powders and laser energy densities were balanced with a high utilization rate of powders and a circular coating morphology.The powder utilization rate was low,and the coating morphology was oval for fewer metal powders.The laser energy density was not enough to melt too many metal powders,and coatings could not be combined with substrates and were easy to fall off.The results provide important guidance for selecting parameters in applying laser cladding to inclined part repairing.
作者
褚梦雅
练国富
姚明浦
冯美艳
CHU Meng-ya;LIAN Guo-fu;YAO Ming-pu;FENG Mei-yan(Fujian Key Laboratory of Intelligent Machining Technology and Equipment,Fujian University of Technology,Fuzhou 350118,China;School of Mechanical and Automotive Engineering,Fujian University of Technology,Fuzhou 350118,China;Research Center for Advanced Manufacturing,Lyle School of Engineering,Southern Methodist University,Dallas TX 75205,USA)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2023年第7期369-383,共15页
Surface Technology
基金
福建省自然科学基金项目(2022J01920)。
关键词
激光熔覆
数值模拟
粉斑直径
粉末浓度
倾斜基体
响应面法
laser cladding
numerical simulation
powder spot diameter
powder concentration
inclined substrate
response surface methodology