Roll-stamp forming of circular tubes

Abstract

Circular tubes are important structural components and generally processed by roll forming technique. In this work, roll-stamp forming is developed as an alternative to roll forming to form circular tubes. A three-pass roll-stamp forming process is designed and implemented, and a corresponding die design criterion is proposed. The finite element model of tube roll-stamp forming is established and forming quality is quantitatively evaluated through simulation and experiment. The deformation process from a flat blank to a circular tube is analyzed, as well as the regularities in the distribution and evolution of stress and strain. In tube roll-stamp forming, no significant thinning or thickening of wall thickness occurs. Finally, the effects of key process parameters on the final forming quality are numerically investigated, and the optimal parameter settings are determined. Forming experiments are conducted and good forming quality is achieved with the optimized process design. Preliminary multi-pass forming experiments are further implemented, successfully enabling the continuous production of tubes. This work makes the first attempt to develop roll-stamp technique as an effective forming approach for profiles of closed cross-sections.