An investigation on the external inversion of thin-walled tubes using a die

The production of sound thin-walled tubular parts by external inversion using a die is normally limited to components having geometrical features within a compact range. Recent published works in the field by Sun and Yang [Int. J. Mach. Tools Manuf. 42 (2002) 15] and Sekhon et al. [J. Mater. Proc. Technol. 133 (2003) 24] present new results relevant to process and die design. However, gaps of knowledge can still be found in understanding the influence of interface friction on the material flow and the effect of strain path and material damage on the occurrence of fracture. The aim of this paper is to contribute to an extension of the actual knowledge of the process by means of a comprehensive theoretical and experimental investigation. Theoretical investigation is accomplished by using virtual prototyping modeling techniques based on the finite element method. Experimental work is performed on Aluminum Al6060 industrial tubes and it is mainly utilized for supporting and validating the theoretical investigation.