The Rollers' Offset Position Influence on the Counter-Roller Flow-Forming Process

Background: The general counter-roller flow-forming (CRFF) process rarely considers the roller's offset position for the symmetric rollers. However, the rollers' offset position can regulate the tube shape, force, and other features. Studying the novel asymmetric CRFF process, which is the CRFF process with the rollers' offset position, is essential. Methods: The influence of the rollers' offset position, the tube blank thickness, thickness reduction on the material deformation, flow-forming force, final tube middle radius, and thickness in the CRFF process are studied using AA5052 aluminum tube experiments and numerical simulation. Result: The final tubes with three tube blank thicknesses, four thickness reduction, and four rollers' offset positions were obtained by the symmetric and asymmetric CRFF processes. Conclusions: AA5052 aluminum alloy tube can be made by the novel asymmetric CRFF process using a small rollers' offset position (-17.5-0%). Different rollers' positions could change the tube's middle radius. With negative rollers' offset position, the outer roller force is larger than the inner roller force. The force differences increase with the increase of tube blank thickness, the increase of thickness reduction, and the decrease of rollers' offset position. The asymmetric CRFF process helps design and construct large tube flow-forming equipment.