Tube Drawing Process with Diameter Expansion for Effectively Reducing Thickness

Abstract

The present paper describes a tube drawing method with diameter expansion, which is herein referred to as “expansion drawing”, for effectively producing thin-walled tube. In the proposed method, the tube end is flared by pushing a plug into the tube, and the tube is then expanded by drawing the plug in the axial direction while the flared end is chucked. The forming characteristics and effectiveness of the proposed method were investigated through a series of finite element method (FEM) analyses and experiments. As a result of FEM analysis, the expansion drawing effectively reduced the tube thickness with a smaller axial load when compared with the conventional method. According to the experimental results, the thin-walled tube was produced successfully by the expansion drawing. Maximum thickness reduction ratios for a carbon steel (STKM13C) and an aluminum alloy (AA1070) were 0.15 and 0.29 when the maximum expansion ratios were 0.23 and 0.31, respectively. The above results suggest that the proposed expansion drawing method is effective for producing thin-walled tubes.