Suppression of Flatness in Circular Tube-Draw Bending by Applying Side Compression

Abstract

The author is studying side compressive processing to compress two sides of a cross-sectional circular tube by dies during bending in order to suppress flatness. In the present research, the experiments were performed by changing the initial thickness of a 5056 aluminum tube with a diameter of 27.2 mm from 2.0 to 3.2 mm. The bending radius R₀ is equal to 3 times the diameter d₀. The experimental results clarified that it is possible to suppress the flatness ratio to 1.6% when the side-compressive displacement is set as δ_c = 1.0 mm. Higher circularity is obtained by side compression with this method. In addition, the forming limit is clarified in terms of side compressive displacement and initial tube thickness.