The Study On The Problem Of Head Bending In Asymmetrical Plate Rolling

Head bending phenomenon in plate rolling is one of important technique problem in rolling field which hasn't be fully solved.During the process,it is good to see that the head is upward slightly.In the actual production,the degree of head bending is serious.Bending too much will cause the problem of production unstable,low rate of products,production and product quality decline and etc.During the process of plate rolling,the primary cause of the head bending when the rolled piece come out of the roller is due to the asymmetrical rolling conditions of up and down surface.There are lots of reasons would lead to uneven rolling.In the actual production,all those factors often affect each other and make the rule of head bending more complex.In this paper,the phenomenon of head bending in the plate rolling process is mainly studied.Based on the relevant literature both at home and abroad,the reason of the head bending phenomenon in the rolling process is analyzed.In addition,this paper also simulates the bending of the head of the workpiece during the asymmetric rolling,and studies the influence of various process parameters on the bending of the head of the workpiece.The main research contents of this paper are as follows:(1)The actual engineering model is transformed into a numerical model.The finite element model of asymmetric plate rolling process was established by the finite element software DEFORM.The problem of head bending of the workpiece is numerically simulated to study the bending of the head of the rolled strip under different rolling conditions.(2)The effects of the reduction rate,the initial thickness,the roller speed ratio of the upper and lower rolls and the rolling line height on head bending state during rolling were investigated.Through the comparison and analysis of the simulation results,the change rule of the head bending height and bending direction of the workpiece was explored with the reduction rate,the initial thickness,the roller speed ratio of the upper and lower rolls and the rolling line height.(3)In the process of asymmetric rolling of plate,the distribution characteristics of the equivalent strain and velocity field in the thickness direction of the head under the roller speed ratio,reduction ratio,rolling line height and initial thickness is investigated.The reason of the head bending phenomenon in the rolling process is analyzed,and the influence of various process parameters on the bending of the head of the workpiece is studied.This is of great theoretical and practical significance for preventing the damage caused by the bending of the rolling head and improving the production efficiency and product quality.