Numerical Simulation On Radial-axial Ring Rolling Process And Blank Design

The radial-axial ring rolling is a continuous and local plastic forming process by usingthe radial-axial ring rolling mills, which is utilized to produce seamless rings with largediameter. Up to now, the major researches about radial-axial ring rolling concentrate onformulating the rolling strategy after the blank dimension has been given, rarely on blankdimension. Blank dimension is an important factor influencing the ring forming. Therefore,studying the blank dimension and process parameters in the large ring forming process isimportant.This paper studies the forming process of a large ring whose outer diameter is1320mm,inner diameter is1081mm and height is350mm, based on actual production data, the blankand ring rolling forming are simulated by using the finite element software ANSYS/LS-DYNA.At the same time, each procedure of the blanks size is designed.A finite element model of the upsetting process is established and simulated. The threeupsetting deformation zones are difficult deformation zone, small deformation zone and easydeformation zone. Because of the uneven deformation, drum shape is formed after upsetting,which induces the additional tensile stress in tangential direction in outer surface of the blank.Axial cracks will be a serious problem if the tensile stress reaches the tensile strength ofmaterial. Simulated upsetting force value is close to the theoretical value, proving the validityof numerical simulation of upsetting. The influence of technological parameters on theupsetting process is analyzed. With the increase of height-diameter ratio, the degree ofdistortion of the forging increases but the force required decreases. With the increase of thefrictional coefficient, both the degree of distortion of the forging and the force requiredincrease, providing the basis for the design of upsetting blank dimensions.Numerical simulation is carried out on the punching process of blind hole and the stressand strain distribution of forging is obtained. The blind hole punch force increases withincreasing stroke. The effect of process parameters is analyzed. When the punch diameter islarge and the punch corner radius is small, the blind hole punch force needed is larger whileforging a serious distortion. Wad punching process is simulated, and strain values of forgingsgradually increase with the increase of stroke. Simulation of wad punch force is close to the theoretical value, which verifies the correctness of the numerical simulation. At the same time,rushed wad punch force increase with the increase of the punch diameter and the thickness ofwad, which lays the foundation for the design of inner diameter sizes.The rolling process of D53K-2500A ring rolling mill is simulated. The strain anddeformation distribution of the ring and the roll force with the curve of time are obtained. Thebasis for optimizing the process parameters is provided. Problems occurred during thesimulation process is analyzed and the solution is put forward.To reduce the tonnage of equipment and decrease the deforming distortion of forgings,the blank dimensions of each process are designed combined with the principle of volumeconstancy. The numerical simulation results show that blank size designed is feasible. Theforces of upsetting and blind hole punch forming process needed decrease while the degree ofdistortion of the forgings also decreases, which provides the basis for the actual production.