Investigation of Friction Coefficient Effects on Fishtail Defect in Hot Ring Rolling Process

Hot ring rolling is a highly nonlinear, unsteady-state and asymmetry process which is affected by many parameters. The friction coefficient between the ring ,the driver roll and the idle roll is one of the problems, which has significant effect on the quality of final product. In this study, the effect of these two parameters on hot ring rolling was investigated based on a 3D coupled-thermo mechanical FE model. The 3D model of ring rolling process was built in ABAQUS including ring, driver roll, idle roll and guide roll. The value of fishtail defect was measured for different friction coefficients between ring and driver roll and also ring and idle roll. The results show that the value of the fishtail defect decreases with the increase of the friction coefficient between the ring and the idle roll or the decrease of friction coefficient between the ring and the driver roll. Furthermore the value of the fishtail defect increases with the decrease of the friction coefficient between the ring and the idle roll or the increase of friction coefficient between the ring and the driver roll. Also the value of these two parameters must be restricted in a specific range, upper and lower values are not allowed. The obtained results may provide a guide for process optimization.