Universal rolling deformation of asymmetric unequal-leg angles

Abstract

Universal rolling of asymmetric unequal-leg angles having an L-section was studied by a model rolling experiment and finite element (FE) analysis. In the experiment, flange spread displayed a linear relationship against the reduction balance, which was defined as the difference of the flange and web thickness strains. Similar linear behaviors of web height, flange depth and bulge height against the reduction balance were also observed. Rolling deformation was also investigated in detail by FE simulation. Although the trends of deformation in the simulation were similar to the experimental results, two significant differences were noted: The inclination of the regression lines of deformation (flange spread parameter) was slightly different, and the change of flange depth was not linear in the high reduction balance region. Furthermore, unexpected web spread was observed in the experiment and FE analysis. FE simulation of universal rolling of channels (U-section), in which the stock had the same half-section as the section of the unequal-leg angle (L-section), was carried out to investigate the similarities in the deformation behaviors of these two products. From a comparison of the upstream section in the two rolling simulations, unstable stock rotation at the entry of the rolls was discovered in unequal-leg angle rolling. The rotation angle was influenced by the reduction balance, and this rotation was considered to be the cause of the distinctive deformation observed in unequal-leg angle rolling. Finally, the importance of restricting rotation was examined with the aim of improving the stability of rolling deformation.