Hot-rolled seamless steel pipe defects

Hot-rolled seamless steel pipe production base deformation process can be summarized as three stages: perforation, extension and finishing.

How to make hot rolled pipe ?

a. Inner surface defects

An inner flap: presenting a straight line, a spiral or a semi-helical sawtooth defect on the inner surface of the steel pipe.

inside scarring: scars in the steel pipe inner surface, generally easily peel off.

Warping: a straight line or intermittent small nail-like tilt leather. Often seen in the capillary head, and easy to peel.

inside straights: a straight shape scratch with a certain width and depth.

inner edge: a straight shape protrusion with a certain width and depth.

inner drum kits: a super and regular protrusion and outer surface is not damaged.

Pull pits: a regular or non-regular pit and the outer surface without damage.

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

An outer fold: the outer surface of the pipe presents a layered folded spiral.

separation: presenting a spiral shape or blocky delamination and cracking.

external scarring: scars on the outer surface.

pock surface: steel surface showed uneven pits.

Line: a substantially symmetrical or asymmetrical linear rolling marks.

Hairline: a continuous or discontinuous hairy fine lines.

net cracks: scaly small cracks.

scratches: linear or spiral-shaped groove-like defects.

touch deflated: the outer surface of the steel pipe rendered in a convex outer concave phenomenon, and pipe wall thickness without injury.

bumps: collision irregular scars.

straightening recess: steel spiral concave outer surface.

rolled off: longitudinally local or long presentation in a convex outer concave folds, the outer surface into strips depression.

crack:opened the rupture surface phenomenon, much produced in the thin-walled tube.

Note: learn about the comparison of seamless and welded pipe.

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