Common 2B surface defects and acceptance (with English terms)
2B surfaces commonly show roll marks, scratches, oxidation tint, poor pickling and waviness. Accept against the standard and an approved sample, and separate repairable from non-repairable.
Cold-rolled 2B is the most common delivery condition. Common defects and acceptance:
| Defect | Chinese | Common cause | Disposition |
|---|---|---|---|
| Roll mark | 辊印 | Damaged roll surface or foreign matter | Light marks may be ground; obvious ones downgraded |
| Scratch | 划伤 | Handling, cut-to-length, slitting contact | Judge by depth and length |
| Oxidation tint | 氧化色 | Poor annealing atmosphere | Affects appearance and corrosion; severe = reject |
| Poor pickling | 酸洗不良 | Insufficient acid/temperature/time | May be re-pickled; severe = downgrade |
| Waviness | 板形波浪 | Rolling, skin pass, coiling tension | Judge by steepness (mm/m) |
| Colour difference | 色差 | Uneven passivation/cleaning | Strict for appearance parts; concession possible for structural |
| Pitting | 麻点 | Corrosion or rolled-in matter | Judge by depth and count |
Acceptance advice:
1) Judge against the standard (GB/T 3280, ASTM A240/A480, EN 10088-2) and an approved sample.
2) Define permitted defects and what is repairable vs non-repairable to avoid whole-lot rejection.
3) Record defect position, size, count and photos.
4) Set different acceptance levels for appearance and structural parts.
2B surface defects usually trace back to rolling, annealing, pickling, skin passing and logistics — tracing the process is more effective than arguing about responsibility.
