Formulae for deformation and strain rate tensors with respect to α-titanium alloy solid billet extrusion have been analytically deduced. Calculations made by the finite element method showed discrepancy between tangential and radial component values. Mathematical simulation showed that prevalence of one or the other component is a function of the radial component. A forecast concerning development of a radial texture in the peripheral layers of a billet in the range of industrially applicable extrusion ratios was made.