Deformation analysis of angle steel rolling in the butterfly roll pass system

Butterfly roll pass system in the actual angle steel rolling is evaluated by deformation mode method developed recently for three dimensional rolling deformation analyses. In the deformation mode method, both 2D rigid-plastic FEM evaluating the velocity fields in the cross-section of billet, and the deformation modes modeling the velocity distribution in the rolling direction are coupled based on the energy theorem to deal with 3D steady state deformation in rolling process. Two types of mode functions with unknown parameters are employed to express the velocity distribution in the rolling direction: the power and the cubic interpolations in the cross-sectional area ratio. To be noted, unknown parameters are determined by optimization of plastic energy, independently of each subregion, into which the whole analytical region is divided. Through the present analysis is found that (1) the features in rolling behaviors can be discussed by these calculated metal flow and strain distribution for the splitting, the butterfly and the finishing passes in the whole roll pass system, and (2) the numerically estimated cross-sectional figures after rolling are in fairly good agreement with the experimental measurements in the actual processing.