Research On Precision Control And Process Parameters Of Straight Thin-walled Flange Rolling Based On Numerical Simulation

The straight thin-walled flange is a typical special-shaped section ring with outer steps,which is widely used in aerospace,automobile,petrochemical transportation,power plant and other fields.The shape of the straight thin-walled flange is relatively complex,and the thickness of the chassis and the neck is quite different.It is difficult to directly roll the rectangular cross-section blank.During rolling process,the contact state between the ring blank and the roll is constantly changing.The unbalanced force of ring blank makes the rolling process unstable.The ring is prone to tilt,which affects the forming quality of the ring.The Q345 straight thin-walled flange was taken as the research object.Based on the theory of ring rolling,the forging diagram,blank structure and rolling pass of the ring were determined.The reasonable range of process parameters is obtained.A three-dimensional finite element model of hot rolling of straight thinwalled flanges was established.The metal flow law during the rolling process of straight thin-walled flanges was analyzed.Based on the metal flow law of straight thin-walled flange parts,the influence of blank structure parameters on the geometric accuracy of rolling ring was studied.In addition,the effects of feed speed,initial ring billet TEMPerature,driving roller speed and friction coefficient between roller and ring on the forming of rolled piece were systematically studied.The main conclusions are as follows :(1)According to the simulation results of ring rolling,the flow law of metal was explored.It is found that the inner and outer surfaces of the ring chassis are subjected to three-dimensional compressive stress during rolling.The neck area where the ring blank does not contact with the roll is mainly subjected to tensile stress.It belongs to the passive deformation zone during the rolling process,and it is easy to produce rolling defects.(2)The tilt of the ring during the ring rolling process is caused by the decrease of the height of the ring.Reducing the inclination angle of the ring neck can effectively reduce the tilt of the ring.The roundness error of the ring decreases with the increase of the inner and outer inclination angles of the blank.(3)By simulating the forming of different process parameters,it is found that the increase of the feed speed of the driving roller promotes the circumferential flow of the ring blank metal and makes the equivalent strain distribution of the ring more uniform.With the increase of the driving roller speed and friction coefficient,the TEMPerature distribution of the rolling ring is more uniform,and the uniformity of the equivalent strain distribution is getting worse.The rolling force of the driving roller decreases with the increase of the initial TEMPerature of the ring billet and the increase of the rotational speed,and increases with the increase of the feed speed.