Different between API 5CT N80 and L80 Oil Casing pipe

Overview of API 5CT N80 and L80 Oil Casing pipe

API 5CT N80 oil casing is an important equipment in oil drilling, main equipment includes drill pipe, tubing and casing, drill collar and small diameter drilling tube.

API 5CT L80 oil casing is also an important equipment in oil drilling, main steel grade includes H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P-110, Q-125.

There are five main differences:

（1）Performance

L80 is a kind of oil well pipe with good resistance carbon dioxide corrosion, good corrosion resistance to sea water, therefore, this performance makes L80 into the common oil casing pipe in ocean oil and gas drilling. N80 steel oil casing is important equipment for oil drilling.

（2）Mechanical Properties Test

N80: Tensile strength ≥517MPa; Yield strength: 379MPa ~ 552MPa; Minimum elongation: 19%

L80: Tensile strength ≥655MPa; Yield strength: 379MPa ~ 552MPa; Minimum elongation: 15%

（3）Heat treatment

PSL1 requirements:N80 and L80 same way (both can be rolled-state delivery);

PSL2 requirements: N80 and L80product should be normalized or normalized and tempered overall, if thick, should be normalized or normalized and tempered after thickened.

（4）Wall thickness detection

PSL1: N80 and L80 for measuring the wall thickness of no coverage requirements;

PSL2: N80 and L80for wall thickness measurement and recording deal with the entire length of the best coverage of the surface area of automatic detection system should reach 25%.

（5）NDT

PSL1: N80 and L80 on the tube did not do destructive testing mandatory requirements;

PSL2: N80 and L80 for all pipe shall be one or more of the criteria specified in 10.15.5 tested to find the inner surface of the outer surface of the pipe and can receive the level of L4 longitudinal imperfections.