The temperature, roll force and roll torque during hot bar rolling

Low-carbon steel bars, 16 mm square, were rolled in four passes, consisting of a square-diamond-square sequence, to a 10 mm square cross-section. The roll separating forces and the roll torques were determined as a function o f the area reduction at entry temperatures of 900, 950, 1000, 1050 and 1100 degrees C. The predictions of the roll forces and torques by several model s were compared to the experimental data, with mixed success, indicating th at further investigations, leading to models of improved accuracy and consi stency, should be undertaken. Alternatively, the finite-element method may be used to simulate the process, provided that a good understanding of fric tion and heat transfer at the contact surfaces is available. (C) 1999 Elsev ier Science S.A. All rights reserved.