Uniformization of Thickness in Rotary Draw Bending of Extruded Aluminum Alloy Square Tube

Abstract

In the process of a tube, a phenomenon called "thickness deviation" occurs, in which wall thinning occurs on the tensile side and the wall thickening occurs on the compressive side. The reduction in wall thickness on the tensile side may result in a loss of strength. Defective phenomena in bending include wrinkling and flattening, and research has been conducted on methods to suppress these phenomena. However, there have been few studies on the suppression of wall thinning. The purpose of this study is to improve the uniformity of wall thickness in the cross section of square tubes after bending. We investigated the effects of the preprocessing cross-sectional shapes of strip and square tubes on wall thickness after bending and examined the cross-sectional shapes that should result in uniform wall thickness after processing.