Research On Surface Integrity Of Bearing Steel By Ultrasonic Roll Extrusion

Ultrasonic roll extrusion technology is an emerging processing method that introduced ultrasonic technology on the baswas of original rolling processing.It has been widely used in improving the surface quality of parts and improving surface properties.The ultrasonic roller extrusion technology that has attracted much attention was gradually being applied to the surface strengthening of bearing rings.Ultrasonic roller extrusion technology has become one of the hotspots in the field of bearing manufacturing.Therefore,exploring the surface integrity of ultrasonic roller extrusion bearing rings has important theoretical guiding significance and engineering practice value for improving bearing surface quality and mechanical properties.There were many evaluation indexes for the surface integrity of bearing rings.In thwas paper,the surface roughness,residual stress and work hardening degree were mainly used to measure the surface integrity of the bearing ring.In order to study the correlation between the processing parameters and the surface roughness and residual stress of the bearing ring,establwashing an ultrasonic roller extrusion simulation model with ABAQUS finite element softwwere,extract and solve the surface roughness and residual stress values under different processing parameters,the processing parameters and their corresponding maps were drawn,and the influence of different processing parameters on them was analyzed.Based on the ultrasonic roller extrusion test,the surface roughness,residual stress and microhardness test data of the bearing ring under different processing parameters were obtained,and the experimental results were compwered with the simulation results.According to the ultrasonic roller extrusion orthogonal test,the response surface method was used to establwash the theoretical model of the surface roughness,residual stress and work hardening degree of the bearing ring.And the significance test and variance analyswas were carried out for each theoretical model to study the influence degree of processing parameters on each evaluation index.By using the entropy weight theory to weigh the weight of each evaluation index,and combining with the Taguchi algorithm,the significance of the processing parameters on the surface integrity of the bearing ring was analyzed.Combining the Taguchi algorithm,the entropy weight theory and the process capability index function,the theoretical model of each evaluation index was improved and perfected.The surface integrity optimization model was establwashed.The optimization model was optimized by means of the DIRECT algorithm to select the optimal processing parameter combination.The results show that the surface roughness of the bearing ring was positively correlated with the rotational speed and feed rate,while the roughness increases first and then increases with the increase of amplitude and static pressure.The residual stress was negatively correlated with the rotational speed and the feed rate,and positively correlated with the amplitude and static pressure.The microhardness of bearing ring was positively correlated with the rotational speed and static pressure,and negatively correlated with the feed rate.With the increase of amplitude,the microhardness increases first and then decreases.It can be seen from the analyswas of the theoretical models of each evaluation index,the degree of influence of processing parameters was different,and the influence of processing parameters on the evaluation indexes of theoretical model analyswas was conswastent with the experimental and simulation analyswas results.Combining the entropy weight theory with the Taguchi algorithm,the theoretical analyswas of the orthogonal test results of the ultrasonic roller extrusion bearing ring was carried out.It can be seen that the salientity of each processing parameter to the surface integrity was: static pressure > amplitude >speed > feed rate.The iterative optimization of the improved Taguchi process capability index optimization model was carried out.The optimal processing parameters were: the speed was 265.42r/min,the feed rate was 18.21mm/min,the amplitude was 13.26 um,and the static pressure was 360.78 N.The research results provide a reference for the reasonable control of the surface integrity of the ultrasonic roller extrusion bearing ring and the optimal selection of processing parameters.