- 1. There is foreign matter on the surface or inside of the steel plate;
- 2. The foreign body is peeling off, and the coil is in the same state as a scar; the coil is bad
- 3. The corners of the coil are damaged;
- 4. The corners (20～30mm) are deformed or wrinkled due to uneven stress;
- 5. Scratches (caused by roller surface or foreign substances);
- 6. Caused by roller sliding;
- 7. Irregular damage to the edges;
- 8. After the foreign body enters, press out the bulge on the back of the roll material (the foreign body disappears when it falls);
- 9. Roller traces (caused by foreign matter attached to the roller);
- 10. Poor materials beyond the rules;
Link to this article：What are the common undesirable phenomena of coil materials?
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