Effect of geometrical parameters on forming quality of high-strength TA18 titanium alloy tube in numerical control bending

The forming quality of high-strength TA18 titanium alloy tube during numerical control bending in changing bending angle beta, relative bending radius R/D and tube sizes such as diameter D and wall thickness t was clarified by finite element simulation. The results show that the distribution of wall thickness change ratio Delta t and cross section deformation ratio Delta D are very similar under different beta; the Delta t and Delta D decrease with the increase of R/D, and to obtain the qualified bent tube, the R/D must be greater than 2.0; the wall thinning ratio Delta t(o) slightly increases with larger D and t, while the wall thickening ratio Delta t(i) and Delta D increase with the larger D and smaller t; the Delta t(o) and Delta D firstly decrease and then increase, while the Delta t(i) increases, for the same D/t with the increase of D and t.