1. Disadvantages of inner surface layer
1 Inward folding: Features: Parallel lines, spiral, semi-spiral zigzag defects are shown on the inner surface of seamless steel pipe.
2 Inner scarring: Features: The inner surface of seamless steel pipe shows scars, and the roots are generally not long and easy to fall off.
3 peeling skin: Features: The inner surface of the steel pipe shows parallel lines or intermittent fingernail-like peeling skin. It mostly appears on the top of the capillary head and is easy to fall off.
4 inner straight: Features: There are parallel linear scratches with a certain total width and depth on the inner surface of the seamless steel pipe.
5 inner edge: Features: There are parallel linear protrusions with a certain total width and depth on the inner surface of the seamless steel pipe.
6 inner package: Features: The inner surface of the seamless steel pipe shows regular convexity and the outer surface is not damaged.
7 dents: Features: The inner surface of the seamless steel pipe shows regular or irregular dents and the outer surface is not damaged.
Two, stainless steel pipe, outer surface defects
1 Outward Folding: Features: The spiral-shaped sheet stretches on the outer surface of the seamless steel pipe.
2 Layer separation: Features: Spiral or small gradations and cracks are displayed on the surface of the seamless steel pipe.
3 outer scars: Features: seamless steel pipe outer surface layer shows scars.
4Surface: Features: The surface of seamless steel pipe shows uneven pits.
5 blue line: Features: The outer surface of seamless steel pipe shows symmetry or different parallel line rolling marks.
6 Hairline: Features: On the surface of seamless steel pipe, continuous or non-continuous hair-like wrinkles are shown.
7 Net-like structure cracks: Features: The surface of seamless steel pipe shows strip-shaped and large scale-like cracks.
8 Scratch: Features: The outer surface of seamless steel pipe is spiral or parallel line groove-shaped defect, most of which can see drainage ditch.
9 collapsing: Features: The outer surface of the seamless steel pipe is concave and convex, and the wall thickness of the seamless steel pipe is not damaged.
10 Knock: Features: The outer layer of seamless steel pipe has irregular scars due to impact.
11 Concave correction: Features: The outer surface of the seamless steel pipe is spirally concave.
12 Rolling and folding: Features: The wall thickness of the seamless steel pipe shows concave and convex folds along the vertical part or the entire length, and the outer surface layer is strip-shaped dents.
13 Cracking: Features: The surface of seamless steel pipe is open and cracked, which is mostly caused in thick-walled pipe. stainless steel pipe
