Analysis of Thick-Walled Oxygen-Free Copper Pipe Production in the Bridge Die Extrusion Process

This article presents the results of research on the possibility of extruding oxygen-free copper pipes in bridge dies. The possibility of continuous production of a finished product of any length with a uniformly deformed wall was analysed. One of the most important elements of the work was to determine the shape of the tool (die and bridge) that would allow durable connection of the material. Numerical studies conducted using the commercial computer programme FORGE^®NxT 2.1, including analysis of the distribution of material temperature and hydrostatic pressure in the welding zone of the bridge die affecting the copper joint during the manufacture of tubular profiles, confirmed the validity of the research issue. The results of the numerical studies were supplemented by laboratory tests, confirming the accuracy of the selected variant of the finished product manufacturing process. The process of bonding under conditions of two-part material compression was used for physical modelling of copper welding. The tests were conducted using the Gleeble 3800 metallurgical process simulator with the PocketJaw module. Based on the analysis of the obtained results, it was found that for tubes with a wall-thickness-to-inner-diameter ratio of 0.5, it is justified to use tools with a longer sizing section and welding chamber, as well as a larger mandrel generating-line angle within the welding chamber.