Tubing coupling is a kind of oil field drilling tools, which is mainly used for tubing connection, mainly to solve the problem of fatigue fracture caused by stress concentration in existing couplings.
The tubing coupling structure is as follows: the tubing end is connected with the inner wall of the hoop body by a conical thread, and the end of the hoop body is connected with the tubing by the same thread and pitch type thread.
The utility model has the characteristics of relieving the stress concentration at the root of the external thread of the tubing with a single taper thread, is not easy to produce fatigue fracture, and the connection effect is good.It can effectively prevent the accident of breaking off of oil well string.The coupling is divided into tubing coupling and casing coupling.
The commonly used steel grades are J55, K55, N80, L80, p110 and so on.
