Study On Impact Friction And Wear Behavior Of Ball Bill Under Dry And Wet Conditions

As one of the key grinding equipment of iron ore,iron ore ball mill drives the grinding ball in the work of massive iron ore falling,impact crushing or grinding,and the lining is badly affected by the effect of ball and iron ore.The service life of the liner is affected by its anti-impact and anti-wear properties directly.This project is supported by National Natural Science Foundation of China,and friction and wear behavior as well as impact friction behavior were studied,so as to learn liner friction properties and wear mechanism of friction and wear in the grinding zone and impact friction characteristics in the crushing zone.All of the work can provide a basis for optimization of material choosing and improving the service life and security.First,theory of medium kinematics and dynamics of the iron ore ball mill was summarized,the running characteristics of ball mill cylinder and steel ball was analyzed according to the basic principle,which provides theoretical preparation for the analysis of liner wear formation;Theory of friction and wear related to the lining plate in the grinding area was summarized,the type of wear was analyzed according to the running condition of the ball mill,which provides theoretical preparation for establishing the friction and wear model.The theory of impact friction in the broken zone was summarized,and provides a theoretical basis for the subsequent establishment of the impact friction model based on the analysis of the impact characteristics of the ball throwing theory.Then,to suit the working condition of the liner in the grinding zone,the friction and wear test rig was designed and assembled.And friction and wear tests were carried out under the dry and wet working conditions,respectively.For the condition of no addition,powder added and slurry added,friction coefficient,friction temperature rise and wear morphology were studied.The dynamic simulation of the continuous pressure contact and relative rotation between the liner and the steel ball is carried out.The stress and strain distribution and the law of the friction temperature rise in the grinding zone are grasped.The deformation behavior of liner is analyzed from the perspective of simulation,and the formation cause of wear morphology is revealed by the distribution characteristics of frictional heat.Finally,to suit the working condition of the liner in the crushing zone,the impact friction test rig was designed and assembled.And impact friction tests were carried out under different liner surface working conditions.For the condition of no addition,powder added and slurry added,impact recovery coefficient,friction coefficient and impact morphology properties were investigated.The dynamic simulation of the liner bearing the impact collision of the steel ball is carried out,and the equivalent stress and energy change law and the plastic deformation of the liner in the crushing zone under the impact of the steel ball was mastered.Through simulation,the residual stress changes after liner deformation are analyzed,and the impact process is described according to the energy change.