Effect of containing a center rib in the rotary draw bending process of 6000 aluminum extruded square tube

摘要

In the process of bending thin square tubes,undesirable phenomena can easily occur. These phenomenainclude flattening distortion of the cross-section, wrinkling onthe compression region and splitting on the tension region. 6063and 6061 aluminum extruded square tubes containing a centerrib, having four kinds of thickness are applied to the rotarybending process. On the section of the square tube, a center ribarranged in the direction of radius of curvature is very effectivein preventing splitting and increasing the limit of bending strain,and further, this rib has secondary effect to reduce flatteningdistortion and wrinkling. In this bending process, applyinglaminate elastic mandrel and additional axial tension to thisworkpiece can improve the working limits. As a result of thisstudy, bend degree H_0/R_0 (where R_0 is the radius ofcurvature on the central plane, H_0 is the height of the squaretube) reaches 0.33 without any defects in this bending processfor the workpiece of 6063S-O with thickness ratio H_0/t_0=40.0.