Corrosion & Finish
Fastener coating selector.
Screen coating options using actual project exposure, joined metals, fastener grade, temperature and whether the fastener is exposed to rain washing or remains sheltered.
Recommended starting point
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Procurement aid only: required coating thickness, friction coefficient, hydrogen-embrittlement controls, HDG thread allowance, electrical isolation and project approval still need to be specified.
| System | Typical strength | Key procurement checks |
|---|---|---|
| Electro-zinc | Thin, economical finish for controlled/low exposure | High-strength grades require hydrogen-embrittlement process controls. |
| Hot-dip galvanizing | Robust zinc layer for outdoor steelwork | Specify ISO 1461 / ASTM F2329 as applicable; account for thread fit/overtapping. |
| Zinc-flake | High corrosion resistance at relatively low thickness | Specify approved system, topcoat, friction range and curing temperature. |
| PTFE / fluoropolymer-type | Corrosion plus controlled friction where approved | Project chemistry, temperature, colour, thickness and coefficient of friction matter. |
| Stainless A2/A4 | Corrosion-resistant base material rather than sacrificial zinc coating | Chloride environment, galvanic pairing, galling and strength class need review. |
| Duplex | Metallic zinc + compatible organic topcoat | Useful for severe exposure when the full coating system is designed/approved. |