Research On The Model And Experiment Of Constitution Relation Of Connecting Rod Bushing Formed By Power Spinning

Power spinning forming technology can make the metal cylinder a change in theorganizational structure and mechanical properties, diesel engine connecting rod bushingformed by power spinning, which has the characteristics of high strength and less cutting, haswidely applied. With the development of computer and numerical calculation, the materialconstitutive relation becomes the bottleneck of the numerical simulation, in the commonlyused numerical simulation softwares, there is no description of the mechanical properties ofpower spinning formed product. Thus, researching the constitutive relation of spinningformed parts under the condition of tensile in room temperature is very important.This paper concentrating on the raw material of connecting rod bushing—QSn7-0.2researches the main process parameters of power spinning forming technology and theinfluence of these process parameters on the mechanical properties and forming quality ofcylindrical workpieces formed by power spinning so that the range of these processparameters has been chosen; Then the orthogonal experiment of three factors and five levelsof power spinning is conducted using three factors—the thinning rate t, stress reliefannealing temperature T, the feed ratio f—selected by the method of orthogonalexperiment, and the specimens are relieved stress by low temperature annealing, the stressdistribution of the specimens in the tensile stress distribution is analyzed based on the finiteelement method, according to static tensile experiment at room temperature the elasticmodulus E and Poisson’s ratio of the specimens are obtained using electric resistantstrain gauge measurement method and incremental method; according to quasi-static tensileexperiment at room temperature force-displacement curve of power spinning formedspecimens is obtained so that stress-strain curves obtained and the mechanical properties parameters needed are attained using graphical method.At last, based on experiment result the bilinear elastic-plastic constitutive relation modeland Ramberg-Osgood constitutive relationship model is explored, and Ramberg-Osgoodconstitutive relation is modified according to the stress-strain curves of spinning specimens,and the stress-strain curve is analyzed respectively when the stress is under and above theproof plastic extension strengthR p0.2, the constitutive relation model of power spinningformed connecting rod bushing is built considering the variation of the process parameters;then based on Mises yield criterion and kinematic hardening model elastoplastic constitutiveequations of power spinning formed connecting rod bushing is obtained, which lays thefoundation for the theoretical research and practical applications of power spinning forming.