... 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 ...