... , R2, R3 4.Gread: J55K55N80L80C90P110 API 5CT Casing and Tubing 1. On sale seamless API-5CT Casing pipe, Tubing pipe, Coupling, OCTG, Oil pipe.2 ... . Our factory manufacture Casing pipe, Tubing pipe, OCTG, Oil pipe for oilfield: According to API SPEC 5CT.3. Steel ... grade: J55, K55, L80, N80, C95, P1104. O. D. Range Tubing pipe ...