HDG≤ 200 °C
Hot dip galvanizing
Studs dipped in molten zinc at about 450 °C. The thickest, longest-lasting sacrificial coating there is — and the one that forces you to overtap the nut, because 85 µm of zinc does not fit in a standard thread.
Specification
| Standards | ASTM A153 Class C · ASTM F2329 · ISO 1461 · ASTM A563 (taro rong dai oc) |
|---|---|
| Thickness | 43 – 86 µm (A153 Class C: trung binh toi thieu 50 µm) |
| Colour | Matt grey, becoming dull over time |
| Maximum temperature | 200 °C |
| Salt spray, ASTM B117 | > 1 000 h — nhung tuoi tho thuc te tinh bang chuc nam ngoai troi |
| Friction | µ ≈ 0,20 – 0,35 — cao va rat kem on dinh; khong nen xiet bang luc ma khong hieu chuan lai |
What it does well
- Sacrificial: the zinc corrodes instead of the steel, and keeps protecting even where the coating is scratched
- Decades of outdoor life with no maintenance
- Lowest cost per year of protection of any coating here
Where it falls short
- The nut must be tapped oversize after galvanizing — a standard nut will not run on
- Friction is high and scattered, so torque control is unreliable without lubrication
- Not for property class 10.9 and above without a documented embrittlement assessment
- Zinc loses its protective behaviour above roughly 200 °C
Specify it when
Structural steelwork, anchor bolts, pipe supports, transmission towers — anything outdoors, exposed, and not routinely dismantled.
Grades we apply it to
Need a quotation?
Send us the grade, size and quantity. We reply within one working day with price, lead time and the certificate package included.