Effects of Rotational Feed at Constant Angles on Forged Shape in Mandrel-Less Incremental Forging of Thick Circular Tube

Abstract

This paper focuses on the formability of mandrel-less incremental forging to produce tubes with variable wall thickness. Tubes with variable wall thickness have advantages in weight saving and resource saving; therefore, their application to industrial parts such as automotive shafts and railway axles is proposed. Conventional forming technologies, for example, radial forging and drawing, require special tools for each tube shape. It is effective to reduce the necessity of special tools to promote tailor-made production by mandrel-less incremental forging. To produce tubes of specified shape and quality by mandrel-less incremental forging, an understanding of the effects of forging conditions on forming characteristics is necessary. As a first step in this research, the effects of rotational feed at a constant angle, which is a simple condition, on forged shape were examined by forging experiments and finite element simulation. The forming characteristics that the forged shape depends on the geometrical contact angle between the workpiece and the die and on the total rotational angle were clarified.