基于综合评分与响应曲面法超声滚挤压加工参数优化

Optimization on ultrasonic roll extrusion processing parameters based on comprehensive scoring and response surface method

为综合改善轴承套圈的表面质量,以表面粗糙度、残余应力、显微硬度为评价指标,对42CrMo钢进行超声滚挤压正交试验。通过对加工参数各水平进行极差分析,得到其对42CrMo钢各表层性能评价指标的影响规律;基于熵权理论确定表面粗糙度、残余应力、显微硬度的权重,构建轴承表层性能综合评价体系,得出加工参数对综合表层性能的影响程度以及最优加工参数组合;通过响应曲面优化得到最优加工参数组合,与综合加权优化后的加工参数组合进行对比,并通过试验验证其准确性。结果表明:表面粗糙度、残余应力和显微硬度占综合表层性能的权重分别为:0.525、0.334和0.141,加工参数对综合表层性能的影响程度为:转速>静压力>振幅>进给速度;两种优化方式的对比试验结果表明,响应曲面的优化效果较好,其最优加工参数组合为:转速为160 r·min^(-1)、进给速度为38.8 mm·min^(-1)、振幅为21μm、静压力为539.4 N,实现了加工参数多目标优化的全局最优。

In order to comprehensively improve the surface quality of bearing rings,taking surface roughness,residual stress and micro-hardness as the evaluation indicators,the orthogonal test of ultrasonic roll extrusion was conducted on 42CrMo steel,and through the range analysis of various levels of processing parameters,the influence rules of the processing parameters on the evaluation indicators of each surface performance for 42CrMo steel were obtained.Then,based on the entropy weight theory,the weights of surface roughness,residual stress and microhardness were determined,and a comprehensive evaluation system of surface performance for bearing was constructed to obtain the impact of the processing parameters on the comprehensive surface performance and the optimal combination of processing param-eters.Furthermore,the optimal combination of processing parameters was obtained by response surface optimization,and compared with the combination of processing parameters after comprehensive weighting optimization,its accuracy was verified by experiments.The results show that the weights of surface roughness,residual stress and microhardness in the comprehensive surface performance are 0.525,0.334 and 0.141,respectively,and the influence degree of processing parameters on the comprehensive surface performance is rotation speed>static pressure>amplitude>feeding speed.The comparative test verification of the two optimization methods shows that the response sur-face optimization effect is better,and the optimal processing parameters are the rotation speed of 160 r·min^(-1),the feeding speed of 38.8 mm·min^(-1),the amplitude of 21μm and the static pressure of 539.4 N,and the global optimization for the multi-objective optimi-zation of processing parameters is realized.