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 of 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 models were compared to the experimental data, with mixed success, indicating that further investigations, leading to models of improved accuracy and consistency, should be undertaken. Alternatively, the finite-element method may be used to simulate the process, provided that a good understanding of friction and heat transfer at the contact surfaces is available. (C) 1999 Elsevier Science S.A. All rights reserved.