Curvature and Residual Stress Analysis in Rotational Leveling of Bars

Leveling process plays an important role in delivering the desired material properties and product standards. An analytical method for the rotational leveling process of bars was presented. First, each cross section of the bar in the leveling area was discretized with the roller gap-curvature relations established in both planes XY and XZ. Second, a numerical procedure with two steps was developed to simulate both pressing and leveling processes. This approach can be easily implemented to produce simulation results of the curvature and trajectory distributions during the leveling process, as well as the bending and residual stresses. It is found that curvature and trajectory distributions follow a sine-shape due to the characteristic of rotational movement, which also results in a helical pattern of residual stress after leveling. Based on the results obtained, it is also observed that the rotational movement is beneficial for adding the number of bending cycle. This is the reason why there are only a few pairs of rollers on the bar leveler.