Finite element analysis on roller-straightening process of equal leg angles

Abstract

Three-dimensional finite element analysis of a roller straightening of an equal leg angle was performed in the present paper in order to validate the usefulness of the employment of FEM to the determination of the intermeshes of rolls in actual roller straightening process. SS400 was employed for the material of equal leg angle. For the plastic constitutive equation of the material, Armstrong-Frederick type combined hardening law was used. Initial shape of the equal leg angle had a uniform curvature lengthwise. A dynamic explicit procedure was used to realize the feeding of the equal leg angle into the intermeshed rolls by rotating the bottom rolls and to accomplish the calculation under the condition of frequent contact-separation between equal leg angle-roll interface. A static implicit procedure was subsequently used to obtain the final shape of equal leg angle by using the last state of equal leg angle by dynamic explicit process. Elastic spring elements were introduced in order to support upper rolls to realize the elastic deflection of the roller straightener apparatus. The spring constant was determined so that straightness of equal leg angle after straightening can be less than 0.1% of its length. The distribution of bending stress, bending plastic strain during and after straightening were observed and discussed. Finally, the effect of intermesh of final roll on the straightness of equal leg angle was calculated.