A commercial purity Al sample was processed using complex shearing of the extruded tube (CSET) technique, which enables the preparation of tubes from bulk samples in one step by combining extrusion and two Equal Chanel Angular Pressing - like passes. In the present paper, the CSET process was simulated and analysed using Finite Element Method. The results of the simulations were compared with the experimental findings. Both modelling and experiment revealed a gradual increase in plastic deformation in the material during CSET processing. Simultaneously, microscopic investigations confirmed concurrent grain refinement. Moreover, a slight gradient of plastic deformation predicted by FEM in the main deformation zone was confirmed by microhardness measurements. In the resulting tube wall, electron backscattered diffraction experiments revealed the presence of fine grains and a partially recovered microstructure. The Vickers microhardness was found to be doubled by the CSET processing.