Outer surface defects of hot-rolled seamless steel pipe.
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.