Study on varying curvature push-bending technique of rectangular section tube

This paper presents a new technique of varying curvature push-bending. Different from conventional bending techniques, varying curvature push-bending makes rectangular section tube blank to deform progressively from large radius to small radius in the process of push-bending. The non-uniform curvature of bending die cavity can be defined by the required bending radius and bending tube material. According to actual applied facility, a involute of circle is regard as varying curvature locus equation. The deformation mechanism of rectangular section tube in the push-bending process is analyzed. Smaller curvature radius comparing to minimum bending radius of the tube of rectangular cross-section can be acquired successfully when the being bending angle is given. Corresponding dies have been designed and manufactured so far, and the experiment of varying curvature push-bending has been carried out. Experimental result verifies that it is possible to apply the new process method.