激光熔覆曲面基体曲线轨迹成形内部质量与效率影响研究

Investigation into forming internal quality and efficiency of the curve path in curved surface laser cladding

曲面基体熔覆层内部孔隙与成形效率的预测与控制是曲面类零部件大面积修复与再制造的前提。本文研究激光功率、扫描速度、气流量、圆柱基体半径对“曲面轨迹”成形内部质量(气孔率)与熔覆效率的作用规律。采用响应面法中心复合设计模块构建了工艺参数与响应目标的数学关系模型。通过方差分析,气孔率及熔覆效率R2分别为95.26%、94.28%,证明所构建模型的可靠性。四个输入参数对气孔率均有显著的影响,激光功率、扫描速度、圆柱基体半径对熔覆效率影响显著。最后基于所建立模型采用期望函数方法对气孔率最小及熔覆效率最大为目标进行综合优化,获得最佳工艺参数为激光功率1.6 kW,扫描速度7 mm/s,气流量1120 L/h,圆柱基体半径40 mm,气孔率及熔覆效率误差率分别为6.755%、5.417%,验证了模型准确性。所建立模型为“曲面基体曲线轨迹”熔覆成形内部质量与效率工艺参数优化及预测控制提供了指导意义。

The prediction and control of the internal void and forming efficiency of the curved surface cladding layer is the premise of large-area repair and remanufacture of curved surface parts.This study investigated the influence of laser power,scanning speed,gas flow rate and radius of the cylindrical substrate on the forming of the“curved path”in terms of internal quality(porosity)and cladding efficiency.The mathematical model of the relationship between process parameters and response targets was constructed by using the central composite design module in the response surface methodology.Based on the analysis of variance,the porosity and the cladding efficiency R2 were 95.26%and 94.28%,respectively,which proved the reliability of the constructed model.The four input parameters greatly affected the porosity;while the laser power,scanning speed,and radius of the cylindrical substrate have a significant effect on the cladding efficiency.Finally,based on the established model,the objective function method was used to optimize the process parameters for the minimum porosity and the maximum cladding efficiency.As a result,the optimal process parameters were laser power 1.6 kW,scanning speed 7 mm/s,gas flow 1120 L/h,and radius of the cylindrical substrate 40 mm.The error rate of the porosity and the cladding efficiency were 6.755%and 5.417%,respectively.The accuracy of the model was further validated.This model provides guidance for optimization and predictive control of process parameters of internal quality and cladding efficiency of the“curved surface substrate with curve path”.