State of strain in the tube sinking process

The FEM calculations of the drawing stress and the effective strain distributions in the tube sinking process were performed. The calculations were done for various process parameters, including different profiles of the working part of the die. Experimental investigations included tube sinking tests of the 1H18N10T steel (approx. 18 % Cr and 10 % Ni). The Vickers hardness (HV5) distributions on the tube cross sections and longitudinal sections, in the deformation zone as well as in the drawn product, were examined. The effective strain distributions were determined basing on HV5 measurements and experimentally obtained hardness curve. The results of experiments were compared with the FEM calculations. The formulated conclusions confirm the usefulness of the method based on hardness measurements in the analysis of the strain fields in drawn products.