the differences between N80 and L80 oil casing

API 5CT N80 and L80 Oil Casing

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.

Tensile test
N80: yield strength of 379MPa ~ 552MPa; tensile≥517MPa; minimum elongation of N80 is 19%.
L80: yield strength of 379MPa ~ 552MPa; tensile≥655MPa; minimum elongation of L80 is 15%.

Impact test
N80 and L80impact test must be done, the minimum size of the sample lateral impact energy 20J, the smallest full-size sample longitudinal impact energy 27J.

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%.

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.