Research On Evolution Mechanism And Control Of Edge Wave Defects In TA2 Tube Roll Forming

In recent years,the use of lightweight materials has become a new inevitable trend.TA2 pure titanium has great industrial value.Under the same strength conditions,TA2 pipes are lighter and thinner than other metal pipes.However,the thinner the metal strip,the more likely it is to become unstable and produce wrinkles,i.e.edge wave defects,during roll bending processing.Edge wave defects are one of the important factors affecting the quality of rolled steel products,and it is necessary to study and find ways to eliminate edge wave defects.In order to solve the actual production problem of a certain roll bending steel manufacturing enterprise,this article aims to explore the evolution mechanism and influence law of edge wave defects in TA2 pure titanium circular tube continuous roll bending forming from theoretical analysis,mathematical analysis,basic material experiments,finite element simulation,industrial roll bending experiments,etc.,and propose control methods for edge wave defects,thereby effectively solving the edge wave problem in pure titanium circular tube continuous roll bending forming.The main research content of the project is as follows:(1)Based on the basic theory of roll bending process and the actual production conditions,the width of sheet metal,the number of roll bending mills,the distribution of roll bending angle,the bottom line forming method,roll gap,roll bending roll and the gap between roll bending passes are established,and the roll bending forming scheme of TA2 thin-walled circular pipe foundation is designed.(2)According to the particularity of TA2 pipe edge wave defects and the correlation between edge wave and mechanical properties of pure titanium,uniaxial tensile test and metallographic test were carried out to obtain the mechanical properties of TA2 pure titanium.By comparing and analyzing the metallographic structure of the products,it was found that the grains in the area without edge wave defects still retain their original single-phase alpha structure,while the grains in the area with edge wave defects were obviously elongated or even destroyed.(3)The model of TA2 pure titanium material was established,the finite element model of tube continuous roll forming was established,the roll bending experimental platform was established and the accuracy of the finite element model was verified.It is found that the longitudinal stress is the main factor affecting the edge wave defects.The edge wave control strategy is put forward by combining the double radius forming method with the up-hill forming method and industrial experiments are carried out,which proves that the forming strategy can effectively control the edge wave defects of TA2 circular tube.(4)From the point of view of bottom line forming method,the effect of up-hill forming method on controlling side wave of circular pipe is better than that of down-hill forming method,and the side wave can not be controlled by horizontal forming method.From the angle distribution of roll bending,double radius forming has the best effect on controlling edge wave of circular pipe,followed by edge forming and circumferential forming.The peak value of side wave increases with the increase of roll gap and bending speed,and decreases with the increase of number of roll bends,distance between roll benders and thickness of sheet metal.