Hot-rolled seamless steel pipe defects


Hot rolled seamless steel pipe
Hot-rolled seamless steel pipe production base deformation process can be summarized as three stages: perforation, extension and finishing.
a. 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 tube surface, and there are obvious rugged feelings.

b. 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.



Welded pipes by manufacturing process

Sunny Steel produce an extensive selection of welded steel pipe including ERW, HFI, EFW, LSAW, DSAW and UOE type carbon steel pipe along with their respective flanges and fittings.

Electric Resistance Welded Pipe
ERW
High Frequency Induction (HFI) Welded Pipe
HFI
UOE (Uing and Oing forming) Pipes
UOE
SAW

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