Effect of interstand tension on roll load, torque and workpiece deformation in the rod rolling process

The effect of interstand tension, resulting from the increase in relative rolling velocity in successive stands of continuous rolling with a round-oval-round sequence, on the roll load, rolling torque and workpiece deformation has been investigated. For this purpose, a simplified analytical approach has been formulated and validated by comparison with available experimental results. Based on this approach, a limiting value was determined for the increase in the ratio of relative rolling velocity between stands. When this limiting value is reached, the state of stress in the workpiece within the roll gap changes to a uniaxial state of stress that can lead to the loss of the ability of the work rolls to grip the workpiece and consequently these changes might make the rolling process unstable. The results have also shown that the roll load decreases with increasing interstand tension while the torque increases with an increase in back tension and decreases with an increase in front tension. The reduction in the outgoing maximum width of the workpiece as a result of interstand tension is linearly related to the increase in the ratio of relative rolling velocity between stands. (C) 2003 Elsevier B.V. All rights reserved.