OCTG Oil Casing Steel Grade Classification

OCTG is the abbreviation of Oil Country Tubular Goods, which usually includes tubing, casing, slotted pipe, drill pipe, drill collar, pup joint and coupling, mainly used in oil and natural gas extraction. This article will introduce in detail the steel grade classification of OCTG oil casing.

OCTG products are required to adhere to the standards set forth in API 5CT to ensure their products are compatible with equipment and operations in the oil and gas industry. The American Petroleum Institute API standard divides casing steel grades into several grades, namely H-40, J-55, K-55, N-80, L-80, C-90, T-95, P-110, Q-125, each grade has a different heat treatment process. In API 5CT, raw materials are divided into four groups. The first group is H, J, K, N, the second group is C, L, T, the third group is P, and the fourth group is Q. The numbers represent intensity levels, and the codes K, N, L, C, and T represent nothing to explain. The following numbers represent the minimum yield strength of the material. The unit is KSI (thousands per square inch), H, N, K, J are the first group, the material's yield strength is 200MPa, L, C, T are the two groups, the material's yield strength is 100 MPa, P110 is the third Group, Q125 is the fourth group.

The API is divided into 4 groups:

The first group represents ordinary pipes, that is, low-strength pipes;

The second group represents sulfur-resistant and corrosion-resistant pipes;

The third and fourth groups represent high intensity levels;

J is the code. The API specification stipulates that the value after the steel grade code is the minimum yield strength in 1000 psi (6894.7632 kPa). For example, J-55, J is the steel grade symbol, and "55" means 55×1000 psi, which refers to the minimum yield strength of steel.

Union Steel Industry is professional API 5CT OCTG manufacturer in China, for detailed information, please check here: Oilfield Tubular Goods