A novel technique for Push bending of thin walled tubes in hydrobending

Tube bending is used extensively in aerospace, automotive and other industries. Wrinkles in thin-walled tubes, changes in cross section and thickness changes during tube bending are the main problems in this process. Compressive force and internal pressure can be used to better control the bending process. If the bend radius to tube diameter ratio (R/D) in the bending process could be between 1 and 1.5, the bending is not done with conventional methods. Providing a new method that results in preventing both wrinkles and minimum tube wall thickness changes is important. In this paper, tubes producing with closed end. Since tube producing with closed end is difficult, in this study, initially closed end seamless tubes are produced by deep-drawing and ironing processes, thereafter tube bending process with ratio (R/D) equal to one was analyzed using experiments and simulations by hydrobending the new method. The pressure in which the tube takes the shape of the die completely without wrinkles, was obtained after investigating pressure changes. The effects of pressure changes on the thickness distribution of the tube inner radius and outer radius of the bent tube was also examined.