Release time：2020-01-16 18:44 Browse：
Select materials based on the environment:
Stainless steel:
304 (A2): General humidity (indoor use).
316 (A4): Molybdenum-enhanced, resists seawater/chemicals (marine/industrial use).
2205 Duplex: Superior chloride resistance (offshore platforms).
Titanium (Ti6Al4V): Excellent for salt/acid exposure (chemical/aerospace industries).
Alloy steel + coating: E.g., Grade 8.8/12.9 with Dacromet or zinc-nickel plating.
Note: Avoid mixing stainless steel with carbon steel to prevent galvanic corrosion.
| Treatment | Features | Best For |
|---|---|---|
| Zinc plating | Low cost, moderate rust resistance | Dry environments |
| Hot-dip galvanizing | Thicker zinc layer, better protection | Outdoor/mild corrosion |
| Dacromet | No hydrogen embrittlement, 1000+ hrs salt spray | Automotive/marine |
| Zinc-nickel plating | 1000+ hrs salt spray, high strength | Military/offshore |
| Hard chrome | Wear + corrosion resistance (may micro-crack) | High-abrasion settings |
| PTFE coating | Chemical/acid resistance, non-stick | Chemical/food processing |
| Black oxide | Decorative, minimal rust protection (requires oil) | Indoor/dry conditions |
Harsh environments (acid/alkali/seawater): Use 316 + PTFE coating or titanium.
Anti-seize lubricant/sealant: Apply (e.g., molybdenum disulfide grease or Loctite 577) to threads.
Nylon washers/gaskets: Prevent liquid ingress.
Cathodic protection (large structures): Pair with zinc anodes in marine settings.
Avoid dissimilar metals: E.g., stainless screws + carbon steel nuts = galvanic corrosion.
Correct torque: Over-tightening cracks coatings, reducing protection.
Regular inspections: Clean and reapply anti-corrosion coatings periodically.
| Environment | Recommended Solution |
|---|---|
| Marine/salt spray | 316 stainless + zinc-nickel plating + sealant |
| Chemical exposure | Titanium or PTFE-coated screws |
| High temp + corrosion | Heat-resistant stainless (A286) or Inconel |
| Humidity + vibration | Dacromet screws + nylon lock nuts |
