L80 oil casing flat end, round thread without coupling or with coupling, partial trapezoidal thread with coupling or without coupling, direct connection thread, special end processing, seal ring structure. There are 10 types of L80 petroleum casing pipe
steel grades H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P-110, and Q-125. Mainly used for oil well drilling.
Introduction to performance inspection of L80 petroleum casing:
1. Physical performance test
(1) According to SY / T6194-96. For flattening test (GB246-97) tensile test (GB228-87) and hydraulic pressure test.
(2) Hydrostatic test, flattening test, sulfide stress corrosion cracking test, hardness test (as specified in the new ASTME18 or E10 version), tensile test, and transverse impact test (according to the American Petroleum Institute APISPEC5CT first edition of 1988) ASTMA370, ASTME23 and related standards are required to be carried out), grain size measurement (ASTME112 new version or other methods).
2. Chemical composition inspection
(1) According to SY / T6194-96. The casing and its coupling are of the same steel grade. Sulfur content <0.045%, phosphorus content <0.045%.
(2) Take chemical analysis samples according to GB222-84. Chemical analysis was carried out in accordance with the relevant provisions of GB223.
(3) American Petroleum Institute ARISPEC5CT1988 first edition. The chemical analysis was made according to the new version of ASTME59, and the chemical analysis was performed according to the new version of ASTME350.