N80 steel pipe is generally casing pipe. N80 casing pipe is an important equipment for oil drilling, and its main equipment also includes drill pipe, core tube and casing, drill collar and small diameter drilling steel pipe.

Domestic casing to geological drilling steel by hot-rolled or cold drawn, steel with "geological" (DZ) said that the commonly used casing steel DZ40, DZ55, DZ753 species.

(1) Casing pipe mainly imported countries: Germany, Japan, Romania, Czech Republic, Italy, Britain, Austria, Switzerland, the United States, Argentina, Singapore also imports. Import standard reference to the American Petroleum Institute Standard API5A, 5AX, 5AC. Steel grade is H-40, J-55, N-80, P-110, C-75, C-95 and so on. Specifications for the main 139.77.72R2,177.89.19R-2,244.58.94R-2,244.510.03R-2,244.511.05R-2.

(2) API provides a length of three: R-1 is 4.88 ~ 7.62m, R-2 is 7.62 ~ 10.36m, R-3 is 10.36m to longer.

(3) Part of the imported goods marked LTC words, that is, long thread buckle casing.

(4) Such as Nippon Steel, Sumitomo, Kawasaki, etc., the steel number is NC-55E, NC-80E, NC-L80, and NC-80E, NC-80HE and so on.

(5) In the case of claims, there have been black buckle, thread damage, pipe folding, broken buckle and thread close distance tolerance, coupling J value of the appearance of defects such as defects and casing brittle fracture, low yield strength quality problem.