API 5CT OIL PIPE

Specification for standard tubing coupling

◆ Purpose Tubing coupling is a kind of oilfield drilling tool, mainly used for tubing connection. The tubing coupling mainly solves the problem of fatigue fracture of existing couplings due to stress concentration.

◆ Structural oil pipe coupling structure is that the end of the oil pipe is connected with the inner wall of the coupling by a conical thread, and the end of the coupling body is connected with the oil pipe by a flat thread with the same thread and the same pitch. It has the characteristics of relieving the stress concentration at the root of the external thread of the single taper thread connecting sleeve, which is not easy to cause fatigue fracture and has good connection effect.

The threads of tubing couplings are divided into non-thickened (NU) and externally thickened (EU). The common steel grades are J55, K55, N80, L80, P110, etc.