Joining of polymer and metal tubes by cold forming

This paper proposes a technology for joining polymer and metal tubes by their ends at room temperature, which is an alternative to structural bonding and mechanical couplings. The technology is built upon a two-stage tube forming process in which the metal tube is firstly expanded with a mandrel and, subsequently, assembled and locked by compression beading with the polymer tube by means of localized plastic instability. The presentation provides details on the tooling system and on the experimental and finite element analysis that were carried out during the development of the proposed technology. Special emphasis is placed on establishing the role of process parameters in the joinability of polymer and metal tubes and determining the maximum internal pressure that these hybrid joints are capable to withstand, without leakage.