Evolution of defects in the production of capillary copper tubes

Features of capillary copper tubes include small internal diameter, increased wall thickness and a specified throughput capacity. This research aimed to reveal the reasons of throughput capacity fluctuations. Manufacturing processes include piercing, hot extrusion and drawing. Defects such as inclusions and pores can occur during all the stages of manufacturing. Inclusions were studied employing scanning electron microscopy. The emergence of porous structures surrounding the inclusions was revealed. It was shown that during drawing such pores turn into channels, which can be later destroyed due to pressure. This process was calculated and analyzed using the ABAQUS finite element analysis software. It was further demonstrated that the inner surface of capillary copper tubes could be destructed along with accumulation of sludge, which would be the cause of throughput capacity fluctuations.