基于NSGA-Ⅱ的Q355C气保焊形貌与性能多目标优化

Multiobjective optimization of morphologies and performance of Q355C gas metal arc welding based on the NSGA-Ⅱ

为了揭示熔化极气体保护焊工艺参数对形貌与性能的影响规律,改善形貌与性能质量,以熔化极气体保护焊预热温度、焊接电压、焊接电流、焊接速度、干伸长为工艺参数,开展混合正交堆焊试验。基于试验数据建立了拟合回归模型来预测焊缝高宽比、硬度和残余应力。试验结果表明,高宽比随着焊接电压的增大而减小,随着焊接电流的增大先增大后减小;硬度随着预热温度和焊接速度的增大而增大,随着焊接电压、焊接电流和干伸长的增大而减小;残余应力随着预热温度的增大而增大,随着焊接电压和焊接速度的增大先减小后增大。基于回归模型,采用NSGA-Ⅱ算法实现多目标优化,并通过实验验证了焊缝高宽比、硬度和残余应力三者间的非劣解。三个输出指标验证试验结果与预测结果的误差值均小于10%,表明了该优化方法的可行性。研究结果为电弧焊接多目标优化及精细化应用提供理论指导。

This work studied the influence law of gas-metal-arc welding process parameters on the morphologies and performance to improve the morphologies and performance. The mixed orthogonal surfacing test was carried out by taking the preheating temperature, welding voltage, current, speed, and wire extension as GMAW process parameters. The aspect ratio decreased with increasing welding voltage, and it first increased and then decreased with increasing welding current.The hardness increased with increasing preheating temperature and welding speed and decreased with increasing welding voltage, current, and wire extension. Residual stress increased with the increased preheating temperature. In addition, it first decreased and then increased with increasing welding voltage and speed. Based on the regression model, the nondominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) was used for multiobjective optimization. After that, experiments were conducted to verify the noninferior solutions among the aspect ratio, hardness, and residual stress. Errors between the predicted and experimental results by the three output indices were all less than 10%, indicating the feasibility of the optimization method. The research results provide a theoretical direction for multiobjective optimization and refined applications of arc welding.