Touch-Up & Repaired Areas
Also called: repair patches · cold galvanizing spots
Appearance
Grey-green zinc-rich paint patches, bright soldered areas, or matte metallized zones within the surrounding hot-dip coating.
Root cause
Legitimate renovation of bare spots or transit damage using ASTM A780 methods: zinc-alloy solder, zinc-rich paint, or thermal spray.
Acceptance verdict
Acceptable within A123's renovation size limits with the repair executed per A780. The thickness rule sits in A123 itself and depends on the method: metallizing or zinc solder must reach the full Table 1 grade for the steel; zinc-rich paint is applied at 75-100 um. Each repaired area may exceed 25 mm in only one dimension, and the total is capped at 0.5% of the accessible surface and 256 cm2 per metric ton.
Acceptable within ISO 1461 limits — total repaired area at most 0.5% of the surface and at most 10 cm2 per area — with repair thickness a minimum average of 100 um unless otherwise agreed, for example matched to the surrounding coating where the article will be overcoated.
This is the question the standards actually answer — describe the defect, then decide: accept, repair, or reject.
Repairable?
Yes — within the standard's renovation limits, using ASTM A780 methods. Repair only within the size and total-area limits set by the governing standard; beyond them the article is re-galvanized.
Remedy at the plant
Document every repair on the inspection certificate — location, method, thickness readings.
Remedy at design
Specify the acceptable repair method in the purchase order if the project restricts zinc-rich paint (e.g., duplex projects prefer metallizing).
Clause references
- ASTM A780/A780M-20
- ASTM A123/A123M-24
- ISO 1461:2022
Standard designations are the property of ASTM International and ISO. This page states the acceptance outcome for this condition — it reproduces no standard text or tables. Verify against the current edition at astm.org · iso.org.