Zn≤ 120 °C
Electroplated zinc
A thin electrodeposited zinc layer, usually 5 to 12 µm, with a chromate passivation on top. Cheap, dimensionally accurate, and honest about what it is: indoor protection, not marine protection.
Specification
| Standards | ASTM B633 (Fe/Zn 5, 8, 12, 25) · ISO 4042 · ASTM F1941 · ISO 4520 (thu dong hoa) |
|---|---|
| Thickness | 5 – 25 µm tuy cap |
| Colour | Clear/blue, yellow chromate, or black |
| Maximum temperature | 120 °C |
| Salt spray, ASTM B117 | 12 – 96 h trong xanh · 96 – 200 h cromat vang |
| Friction | µ ≈ 0,12 – 0,20 — chap nhan duoc nhung phan tan hon PTFE |
What it does well
- Thin enough that standard nuts still fit — no overtapping
- Cheapest coating that gives a clean, saleable finish
- Short lead time — plated in-house in a day
Where it falls short
- Hydrogen embrittlement risk on anything above 1 000 MPa or 31 HRC: baking within 4 hours of plating is mandatory, not optional
- The chromate layer breaks down above about 70 °C, taking most of the corrosion resistance with it
- Will not survive marine or chloride exposure
Specify it when
Indoor equipment, machine assembly, dry utility piping, and anywhere the fastener is not exposed to weather.
Grades we apply it to
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