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The defects of hot-rolled steel pipe

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.

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