Numerical simulation of cold drawing of steel tubes with straight internal rifling

Abstract In heat exchangers, steel tubes with straight internal rifling bring several benefits to the heat transfer process. However, production of such tubes by cold drawing brings considerable challenge in meeting strict dimensional criteria on a rifling geometry. Optimization of the whole production process naturally involves a numerical simulation of cold drawing, saving time and costs of pre-production plant trials. The key aspect of a multi-rifled tube production is the proper creation of internal rifling via gradual filling of plug grooves during drawing. It is this very mechanism where the benefit of numerical simulation steps in, providing us with qualitative and quantitative estimation of important state variables. In this article, four hollows have been compared as an input feedstock for cold drawing of O25.4 × 2.11 mm multi-rifled tube. The calculated state variables in a feedstock material (i.e. stresses, strains, and strain rates) uniquely determine the material flow during drawing. The results of numerical simulations helped us find the most suitable input hollow for given tube dimensions while meeting customer’s strict dimensional tolerances on internal rifling. Additional tasks involved optimizing the axial position of the plug inside the die.