Dieless drawing of stainless steel tubes

This study develops a dieless drawing prototype machine for tube or wire drawing processes. The proposed dieless drawing machine is composed of three main parts: a supporting frame, a heating device, and a transmission system. A high-frequency heating apparatus serves as the heating source, and an infrared thermocouple is used to monitor the heating temperature. A servomotor moves the heating coils in the opposite direction to the drawing clamp table to control the relative speed and area reduction of the stainless steel tube workpiece. A series of experiments were conducted to test the effects of different relative speeds between the heating source and drawing clamp table. The maximal area reduction achieved was approximately 40 % of the initial cross-sectional area at a drawing speed of 0.8 mm/s. Finite element simulations were also conducted to analyze the formable regions at different relative speed ratios, drawing speeds, and heating temperatures. The study verifies the validity of the numerical model by comparing the area reductions and shape similarity of the drawn tubes to numerically predicted and experimentally measured values.