Causes of Common Surface Defects of Cold Rolled Strip

Release time:

2022-06-23

The types and causes of surface defects of cold-rolled strip steel are very complicated. Surface defects may occur in every process from steelmaking, hot rolling, cold rolling to user use. Therefore, surface defect control is essential. Next, the cold-rolled steel strip manufacturer-hualuo steel strip co., ltd will make a simple analysis for everyone.

1. Holes

Cause: material tear holes. During the rolling process, the cross-section of the strip is partially loose, and the stress exceeds the deformation limit of the material. The thinner the strip, the more obvious the phenomenon. Due to inclusions, bubbles, shrinkage cavities, etc., during the casting process, local cracking will occur as the thickness of the strip decreases during the later rolling process.

2. Cracks

Reason: The strip extension is uneven during the rolling process, the original defects on the strip surface are not completely removed, and there are non-metallic inclusions or subcutaneous bubbles on the strip. In addition, incorrect roll adjustment and incorrect roll profile design during cold rolling can also lead to cracks, such as excessive tension and improper chemical composition.

3. Dents

Reason: Roller surface defects or foreign matter are formed when the surface of rolled-in strip falls off, and the thin strip is concave on one side and convex on the other.

4. Roller printing

Reason: the hardness of the roller surface is not enough, and hard impurities such as metal chips are easy to stick to the roller surface. It is also possible that the strip steel has high strength, careless operation, peeling off the roller surface, and roller printing. This defect is easy to judge and can be eliminated in time.

5. Scratch

Reason: rolling mill guide plate rough. Or in the winding process, the strip steel friction foreign matter.

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