Development of a simulation model of the rotary tube piercing process and fem application to improve the quality of seamless tubes

This research focuses on the understanding and FEM modelling of the phenomena that affect a rotary tube piercing process or Mannesmann process and has been developed in cooperation with a company (TENARIS-Dalmine S.p.A.). The work has been divided into two parts. In the first one the 2D FEM model definition and implementation is presented. In this phase the aspects related to the schematization of a three-dimensional process into a two-dimensional one were discussed with the Company. The second part deals with the simulative analysis of the hole beginning and propagation, and the comparison between simulation and experimental results. This comparison allowed the critical damage value to be evaluated, for the materials used by the Company, and identified the beginning of the bar failure (Mannesmann effect) in the simulations. The material breakage was studied using a customized version of the commercial finite element code DEFORM 2D. The good agreement between simulation results and experimental tests shows the capability of the FEM code to furnish good indications in the optimization of a rotary tube piercing process.