ISO 10683
Fasteners — Non-Electrolytically Applied Zinc Flake Coating Systems
Specifies non-electrolytically applied zinc-flake systems for threaded and non-threaded steel fasteners.
What ISO 10683 specifies
ISO 10683 specifies zinc-flake basecoats with optional topcoat and lubricant for steel fasteners, especially high-strength fasteners where avoiding internal hydrogen embrittlement is important. Its designation communicates basecoat flZn or lubricated flZnL, chromium status yc or nc, topcoat TL or Tn, added lubricant L, required neutral-salt-spray duration, and friction category. Corrosion resistance is decisive; reference system thicknesses are about 4, 5, 6, 8, and 10 µm for 240, 480, 600, 720, and 960 hours. Buyers must also state torque/clamp-force requirements, color, material limits, and thread gaugeability.
ISO 10683 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Thickness | Requirement / test |
|---|---|---|---|
240 h reference | Minimum neutral-salt-spray duration; reference system thickness only. | ≥ 4 µm ≥ 0.16 mil | ISO 9227 NSS; corrosion performance governs. |
480 h reference | Minimum neutral-salt-spray duration; reference system thickness only. | ≥ 5 µm ≥ 0.2 mil | ISO 9227 NSS; corrosion performance governs. |
600 h reference | Minimum neutral-salt-spray duration; reference system thickness only. | ≥ 6 µm ≥ 0.24 mil | ISO 9227 NSS; corrosion performance governs. |
720 h reference | Minimum neutral-salt-spray duration; reference system thickness only. | ≥ 8 µm ≥ 0.31 mil | ISO 9227 NSS; corrosion performance governs. |
960 h reference | Minimum neutral-salt-spray duration; reference system thickness only. | ≥ 10 µm ≥ 0.39 mil | ISO 9227 NSS; corrosion performance governs. |
Tests and the drawing call-out
Tests the document imposes
- Neutral salt spray by ISO 9227
- Coating thickness
- GO-gage thread fit by ISO 1502
- Torque/clamp-force or coefficient-of-friction testing
- Adhesion and appearance
- Hydrogen-embrittlement process review
How to cite it
Drawing call-out
ZINC FLAKE PER ISO 10683: flZn<|L>/<yc|nc>/<TL|Tn>[/L]/<HOURS>h/<FRICTION CATEGORY>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Finishes specified to ISO 10683
ISO 10683 — frequently asked
Does ISO 10683 define mandatory thickness classes?
No. Its listed thicknesses are references associated with corrosion durations; salt-spray performance is decisive.
What does nc mean?
It means the coating system is free of hexavalent chromium. The designation should also state topcoat, lubricant, hours, and friction needs.
Why specify friction?
Fastener preload at a given torque is highly sensitive to coating friction. A corrosion-only callout can produce unacceptable clamp-load scatter.
ISO 10683 is copyrighted by International Organization for Standardization. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗