The depth of appearance defect is not more than 12.5 % of the standard wall thickness of the pipe body .
Diameter gauge=1067mm =d-(2.38,3.18)mm
Diameter gauge =152mm =d-3.18mm
a. The tube ends are chamfered and must be completely inverted at the end of the tube 360 degrees; the diameter of the chamfer should make the thread bottom disappear at the chamfer, not disappear at the tube end, and no knife-like thin edge appears. There should be no burrs on the inner and outer edges of all tube ends. b. The tube end is within the minimum length Lc of the full top thread , and the thread has no obvious tear, knife cut, wear scar, shoulder, or continuity defects. The first buckle can’t have glitches. c. 2-3/8” ～7 ” black top thread shall not exceed 7 buckles.
a Finished collars must not have cracks, cracks, and voids that can be checked; from the center of the collar J to the end of the pipe, the threads should be free from any obvious tears, cuts, scratches, shoulders, or any imperfections in continuity. There must be no burrs on the inner and outer edges of both ends; b. Allowable depth of flaws for pits and round bottom chisels: <3-1/2” (0.76mm) < 6-5/8” (0.89mm); grip marks and sharp bottoms The allowable depth of cut of the chisel is less than 6-5/8 (0.76mm); c. The surface of the threading surface of the coupling thread is tested with the test solution and the color change time is more than 3 minutes; after the phosphating, the color is light gray or dark gray. The film should be dense, continuous, and uniform in crystal, and loose Phosphate film layer, rust and green spots, local non-phosphating film, and serious ashing on the surface should not be allowed.
J55: One Green K55: Two Green N80-1: One Red N80Q: One Red and Green Belt L80-1: One Red Belt and Brown Belt P110: One White Belt
J55: Green and a white band (no white band on the tubing) K55: Green N80-1: Red N80Q: Red and a green band L80-1: Red band and a brown band P110: White
Body: <4-1/2″: 4.8mm ≥ 4-1/2”: 6.4mm
Coupling <4-1/2″: 6.4mm
Note: (1) This technical standard is based on the contents of API Spec 5CT and 5B (the latest edition). (2) Development date: November 2008