Simulation And Experimental Study On The Effect Of Heat Treatment On Residual Stress Of Power Spinning

The connecting rod bushing of the diesel engine will be subjected to friction between the small head of connecting rod and the piston pin and the burst pressure of the cylinder?the reciprocating inertial force of the connecting rod during the working process,so there are high requirements on the quality and performance of connecting rod bushings.Power spinning is a machining process for thin-walled cylindrical parts.The rod bushings produced by it have good mechanical properties,fatigue strength and load carrying capacity.During the spinning process,the plastic deformation and the flow of metal materials of the blanks will lead to the generation of residual stress.Since the residual stress has many hazards,it must be eliminated.At present,the heat treatment is commonly used in mechanical machining to eliminate the residual stress of the workpiece.Therefore,it is of great significance to study the effect of heat treatment on the residual stress of the connecting rod bushing of power spinning.In this paper,a certain type of tin bronze(QSn7-0.2)connecting rod bushing sleeve-shaped parts as the research object,study the effect of annealing temperature and holding time on its residual stress.Firstly,a 3D solid model of three-wheel offset spinning was built,which was then imported into Simufact.forming finite element analysis software to simulate the power spinning process.Then,the model with stress result data after spinning simulation is imported into the software's heat treatment module,and a single factor scheme is designed and perform multiple sets of heat treatment simulations.The results show that the heat treatment doesn't change the manifestation of the residual stress.Axial and tangential residual stresses still appear as compressive stresses and tensile stresses;and values of axial and tangential residual stress both decrease with the increasing of annealing temperature and holding time.Design test to verify the reliability of the simulation.Cylindrical parts are machined with the same parameters as the spinning simulation.Then heat treatment of the cylindrical parts is carried according to the scheme in the heat treatment simulation.And a cylinder part without heat treatment was set up for comparison.X-ray diffractometer was used to measure the residual stress of the above cylindrical parts.And compare the measurement results with the simulation results,it was found that:for the cylindrical parts without heat treatment,the manifestations of axial and tangential residual stresses of the test and simulation are the same and the rule of stress distribution is basically the same,except that the stress value measured by the test is slightly larger than the value obtained by the simulation.There is no change to the manifestations of axial and tangential residual stress of the test and simulation after heat treatment and the values of stress decrease with the increasing of annealing temperature and holding time.And when the annealing temperature reaches 290 °C,the reduction of residual stress is significantly lower;When the holding time reaches 2h,the residual stress has almost no change.It can be considered that the simulation results are basically consistent with the actual situation and can provide a certain reference for actual production.