ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods
ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods.
1. Scope & Application
Category
Description
✅ Applies To
Batch Hot Dip Galvanizing of fabricated iron and steel articles (including certain castings).
❌ Excludes
Continuous sheet, wire, and woven/welded mesh.
❌ Excludes
Tube and pipe galvanized in automatic plants.
❌ Excludes
Fasteners (e.g., bolts, nuts) which have their own specific standards.
2. Key Terms & Definitions
Term
Definition
Significant Surface
The part of the article essential for serviceability or appearance (must be covered by coating).
Reference Area
An area (min. 10 cm²) where measurements are taken.
Local Thickness
The average of at least 5 magnetic measurements within one reference area.
Mean Thickness
The average of the Local Thickness values from all reference areas in the sample.
3. Visual Inspection Criteria
Inspect from a distance of not less than 1 meter.
Feature
Status
Requirement / Note
Blisters
❌ REJECT
Raised areas without solid metal beneath are not permitted.
Sharp Points
❌ REJECT
Roughness/points capable of causing injury are not permitted.
Uncoated Areas
❌ REJECT
Must be renovated (see Section 6) or re-galvanized.
Flux/Ash
❌ REJECT
Residues must be removed if they affect use or corrosion resistance.
Dark/Light Areas
✅ ACCEPT
Cellular patterns or dark grey areas are acceptable.
White Rust
✅ ACCEPT
“Wet storage stain” is acceptable if coating thickness is sufficient.
Weld Seepage
✅ ACCEPT
Staining from intermittent welds is acceptable (aesthetic only).
Note on Adhesion: Adhesion testing is not normally carried out. The coating should withstand normal handling. Tests (e.g., cutting) must be agreed upon before galvanizing.
4. Sampling & Testing Protocol
Step A: How Many Articles to Pick?
Select a random Control Sample from the inspection lot.
Lot Size (Articles)
Minimum Control Sample Size
1 to 3
All articles
4 to 500
3 articles
501 to 1,200
5 articles
1,201 to 3,200
8 articles
> 3,200
13 articles (up to 10,000)
Step B: Where to Measure?
Choose reference areas based on the size of the individual article.
Article Size (Significant Surface)
Required Reference Areas
Placement Guide
Large (> 2 m²)
At least 3
Approx. center, and ~100 mm from each end.
Medium (> 100 cm² to ≤ 2 m²)
At least 1
Representative area.
Small (≤ 100 cm²)
1
Group articles to make 10 cm² surface.
⚠️ CAUTION: Do not measure less than 10 mm from edges, flame-cut surfaces, or corners.
Step C: What If It Fails? (Re-Sampling)
If the original control sample fails thickness requirements, follow this procedure.
Step
Action
Outcome
1. Re-Sample
Take a new sample from the lot, twice the size of the original.
–
2. Test
Measure the new sample.
If Pass: Accept the whole lot.
3. Result
If the new sample fails:
If Fail: Reject non-conforming articles (or re-galvanize).
5. Coating Thickness Requirements
A. Standard Articles
Use for items not centrifuged (beams, plates, etc.).
Steel Thickness
Local Thickness (min)
Mean Thickness (min)
> 6 mm
70 µm
85 µm
> 3 mm to ≤ 6 mm
55 µm
70 µm
≥ 1.5 mm to ≤ 3 mm
45 µm
55 µm
< 1.5 mm
35 µm
45 µm
Castings > 6 mm
70 µm
80 µm
Castings ≤ 6 mm
60 µm
70 µm
B. Centrifuged Articles
Use for small parts spun to remove zinc (fasteners, washers).
