Initial stage of titanium alloy tube billet extrusion: simulation and experiment

Abstract

This article presents the results of the modeling of the behavior of the titanium alloy Ti-3Al‑2.5V at the initial stage of extrusion of a tube billet. The influence of the gaps between the surfaces of the tool and the billet on the nature of its shape change and the strain state is discussed. In particular, the most deformed tube parts of the maximum (by modulus) strain tensor values are identified. The dependence of the Ti-3Al‑2.5V alloy tube extrusion force on the stroke of the pressure pad is calculated. The results of the calculation of the maximum forces and the forces at the steady-state stage are in good agreement with the data obtained under an industrial experiment. Horizontal extrusion leads to an asymmetry in the location of the deformation fields relative to the extrusion axis. Accordingly, an asymmetric distribution of properties arises in the extruded tube, which is experimentally confirmed using hardness measurements. Correspondence is established between the simulation data on the heterogeneity of the strain distribution over the wall thickness of the hot-pressed tube made of titanium alloy Ti-3Al‑2.5V, considering the pressing-out, with the results of micro- and X‑ray structural studies of the tube semifinished product obtained.