Standard for Steel Grade of Petroleum Casing

The steel grades of casing include H40, J55, K55, M65, N80, L80, C90, C95, T95, P110, q125 and V150.

H40 is a low-grade steel, which is rarely used in the market.

The yield strength of J55 and K55 belongs to the same level. The difference between them is that the tensile strength of K55 is higher than that of J55.

N80 is divided into n80-1 and N80Q.

L80 is divided into l80-1, l80-9cr and l80-13cr.

C90 is divided into c90-1 and c90-2.

Q125 is divided into q125-1, q125-2, q125-3 and q125-4.

V150 is a non API high strength steel, which is mainly used for deep and ultra deep wells.