The external upset end (EUE) API tubing uses taper pipe with round thread. It realizes connection and seal through the joint upsetting. After the thickening of both ends, heat treatment, thread processing, and installing of the coupling and thread protector are carried out in order.
The EUE API tubing has two main features. Without changing the thread shape, the joint size increases through the upsetting process. This leads to a substantial increase in the connection strength and meets the requirement of downhole operation. In addition, it achieves sealing effect through the thread compound. There is a 0.076mm gap between addendum and crest. When tightening threads, the crest clearance is filled with thread compound. After the compound after is solidified, it will block the leak channel, so as to achieve the sealing effect.