Research On Evolution Of Shot Blasting Process And Mechanism Of Mobile Shot Blasting Machine

In this paper,the research object was shot blasting machine of LKP550 type mobile shot blasting machine.The discrete element software was employed to the simulate the macroscopic motion process of steel shot in shot blasting machine,and it analysised the influence of steel shot diameter,impeller rotation speed,installation angle between sub-wheel and impeller on magnitude and stability of steel shot velocity,the purpose was to determined process parameters for the finite element analysis of shot blasting,then took Q345 steel as an example,the finite element method was used to simulate the microscopic process of stress-strain of Q345 and further focused on the influence of steel shot diameter and velocity on the distribution of residual stress field.The main research conclusions of this paper were as follows:The main influencing factors of steel shot velocity was obtained based on the theoretical analysis of evolution of steel shot along the sun-pill wheel blade and impeller blade in the LKP550 type mobile shot blasting machine,and the main influencing factors of shot blasting effect was obtained based on the theoretical analysis of shot blasting mechanism.The movement state of the steel shot in the shot blasting machine was analyzed by the discrete element software,the results demonstrated that the impeller rotation speed has the greatest influence on the steel shot velocity,and it verified the correctness of linear proportional between impeller rotation speed and steel shot velocity in the theoretical analysis,steel shot diameter and installation angle between sub-wheel and impeller are the most important factors affecting steel shot velocity.Small steel shot diameter,impeller rotation speed,installation angle between subwheel and impeller or large impeller rotation speed will lead to the steel shot velocity is not stable.In order to ensure the stability of steel shot velocity and shot blasting effect,the paper selected the steel shot diameter between ?0.6mm to ?2.0mm,impeller rotation speed between 2250 rpm to 2950 rpm,installation angle between 11° to 20° as the process parameters of the follow-up shot blasting analysis.On the basis of discrete element simulation,the paper selected the shot blasting process parameters by optimized and took Q345 steel as an example,it mainly studied the influence of steel shot diameter(?0.6mm~?2.0mm)and steel shot velocity(60 m/s~80m/s)on microscopic process of stress-strain of Q345 by shot blasing.The results showed that steel shot diameter have great effect on the residual stress layer at the same steel shot velocity and the steel shot velocity have great effect on magnitude of residual stress at the same steel shot diameter.Even more,the shot blasting effect is not obvious if the steel shot velocity and diameter are too small,and if them are too large will lead to the generation of tensile stress what do great damage to shot blasting on the material surface.For the Q345 steel,it is a suitable process parameters for shot blasting that steel shot diameter between ?1.0mm to ?1.4mm and steel shot velocity between 70m/s to 75m/s.In addition,it is feasible that through the macroscopic process analysis of the steel shot during the shot blasting process by on discrete element method and microscopic process of stressstrain of Q345 by on finite element method show that combining these two methods study the evolution of shot blasting process and mechanism.