Formability Enhancement in Titanium Tube Flaring by Controlling the Deformation Path

Abstract

The tube flaring process has been traditionally used to expand one end of the tube without changing its main cross-sectional area. This simple process typically forms the product with a single punch along a unique deformation path. To delay failure and enhance formability, a two-step flaring process can be used. For example, if a significant elliptical flared shape is attempted in a one step process, a tearing failure would occur on the major elliptical axis. However if a two-step process with a mildly elliptical punch, followed by the final elliptical punch was used, the desired elliptical shape can be achieved. In this paper the effects of the punch geometry and forming depth of the first step on the deformation paths were numerically analyzed. By changing the deformation path, failure can be delayed so that higher formability is achieved. The numerical simulations were validated by comparison with experimental results.