A research on the forward slip coefficient in alloyed bar rolling by the Round-Oval-Round pass sequence

For predicting the forward slip coefficient and veocity of outgoing workpiece exactly during alloyed bar rolling by Round-Oval-Round pass sequence, the influence of the spred of the outgoing workpiece and its contact boundary condition was considered and the calculating formula for the effective height of outgoing workpiece and the mean roll radius was proposed individually. Moreover, the new parameters were substituted into the Shinolcura and Takai Formula to modify it. Then a modified forward slip coefficient firmula was proposed. The validity of the theoretical model has been examined by the bar rolling experiment and the numerical simulation using three-dimensional rigid-plastic FEM. Compared with the Shinokura and Takai dormula, the predict accuracy of the modified formula was improved apparently. So, it can be applied in alloyed bar rolling to predict the the forward slip coefficient and veocity of outgoing workpiece exactly.