基于响应面法的激光熔覆Ni基涂层气粉两相流研究

A study on gas-powder two-phase flow of Ni-based coatings by laser claddingbased on response surface methodology

为了揭示激光熔覆中输入参数的相互作用对粉末流汇聚性的影响规律,提高熔覆过程中的粉末利用效率,采用响应面法进行模拟方案设计,通过拟合输入参数与粉末流特征参数之间的函数关系建立回归方程,揭示输入参数及其相互作用对基体上平均粉末浓度与粉斑直径的影响规律。研究结果表明,气流量、送粉电压、喷嘴工作高度、气流量与喷嘴工作高度的交互项、送粉电压与喷嘴工作高度的交互项、喷嘴工作高度的二次项对基体上平均粉末浓度影响显著。气流量、喷嘴工作高度对基体上的粉斑直径影响显著。基体上平均粉末浓度随气流量增加而减小,随送粉电压增加而增大,随喷嘴工作高度增加而减小;基体上粉斑直径随喷嘴工作高度和气流量增加而增大。以基体上平均粉末浓度最大,粉斑直径最小为优化目标,基体上平均粉末浓度与粉斑直径的模拟值与预测值进行比较,误差分别为6.6%和1.74%。该研究可以为激光熔覆技术在工业应用中参数选取提供理论指导。

A simulation scheme was designed with response surface methodology(RSM)to reveal the influence law of the interaction of input parameters in laser cladding on the convergence of powder flow as well as improve powder utilization in the cladding process.Regression equation was established by fitting functional relationship between the input parameters and the characteristic parameters of powder flow to present the influence law of the input parameters and their interaction on average powder concentration and powder-spot diameter on the substrate.The research result show that average powder concentration on the substrate is significantly affected by airflow,powder-feeding voltage,nozzle′s working height,the interaction term of airflow and nozzle′s working height,the interaction term of powder-feeding voltage and nozzle′s working height,and the quadratic term of nozzle′s working height.The airflow and working height of the nozzle significantly affect the diameter of the powder spots on the substrate.Average powder concentration on the substrate decreases with increased airflow and increased nozzles′working height,and increases with increased powder-feeding voltage.The diameter of the powder spots on the sub‐strate increas with increased nozzle′s working height and increased airflow.The optimization goal referred to the maximum average powder concentration on the substrate and the minimum powder spot diameter.The simulated values of average powder concentration on the substrate and powder-spot diameters are compared with the predict‐ed values,and the errors are 6.6 and 1.74%,respectively.The work can provide theoretical guidance for the parame‐ter selection of laser cladding technology in industrial applications.