Flange forming at an arbitrary tube location through upsetting with a controllable deformation zone

Abstract

Instability is the most common challenge faced in the production of tubular flanged parts, which is usually limited by dimensional parameters, such as the slenderness ratio of height to thickness and the ratio of initial tube thickness to final flange thickness. To extend the formability limit in a single step, an alternative forming method called upsetting with a controllable deformation zone (U-CDZ) is proposed in this paper. In the proposed method, the workpiece is pushed from the holding cavity of a die into the forming cavity. Under an appropriate counter force, a stabilized deformation zone is established, which eliminates the limitation of the initial slenderness ratio in the conventional upsetting method. Detailed analyses of the forming qualities and forming load were performed. Due to the employment of the location zone, the tube flange could be formed at an arbitrary location (at the end of tube or away from the ends) without defects. The feasibility of the U-CDZ method was validated through finite element modelling and metal experiments on aluminium.