A. outer surface defects 1. An outer fold: the outer surface of the pipe presents a layered folded spiral. 2. separation: presenting a spiral shape or blocky delamination and cracking. 3. external scarring: scars on the outer surface. 4. pock surface: steel surface showed uneven pits. 5. Line: a substantially symmetrical or asymmetrical linear rolling marks. 6. Hairline: a continuous or discontinuous hairy fine lines. 7. net cracks: scaly small cracks. 8. scratches: linear or spiral-shaped groove-like defects. 9. touch deflated: the outer surface of the steel pipe rendered in a convex outer concave phenomenon, and pipe wall thickness without injury. 10. bumps: collision irregular scars. 11. straightening recess: steel spiral concave outer surface. 12. rolled off: longitudinally local or long presentation in a convex outer concave folds, the outer surface into strips depression.
13. crack:opened the rupture surface phenomenon, much produced in the thin-walled tube.
B. Inner surface defects
1. An inner flap: presenting a straight line, a spiral or a semi-helical sawtooth defect on the inner surface of the steel pipe. 2. inside scarring: scars in the steel pipe inner surface, generally easily peel off. 3. Warping: a straight line or intermittent small nail-like tilt leather. Often seen in the capillary head, and easy to peel. 4. inside straights: a straight shape scratch with a certain width and depth. 5. inner edge: a straight shape protrusion with a certain width and depth. 6. inner drum kits: a super and regular protrusion and outer surface is not damaged. 7. Pull pits: a regular or non-regular pit and the outer surface without damage. 8. internal thread (this defect produced only at Accel units): spiral traces often seen in the thin-walled pipe surface, and there are obvious rugged feelings.