A Complete Solution for Anti-Corrosion and Service Life Extension of Fasteners
2026-03-27
As core connecting components in industrial equipment, fastener corrosion directly leads to connection failure, reduced equipment accuracy, and even safety accidents. According to industry statistics, approximately 35% of mechanical equipment failures are caused by fastener corrosion and fatigue damage. By implementing a full-process technical strategy covering material selection, standardized surface treatment, regulated storage and transportation, and precise installation protection, the service life of fasteners can be effectively extended by 2–5 times, ensuring stable long-term operation of industrial equipment.
Combining national and industrial standards with advanced protection technologies, this article provides a systematic, professional solution for anti-corrosion and service life extension of fasteners.
1. Precise Material Selection: Eliminating Corrosion Risks at the Source
Fastener material selection must precisely match the corrosion level, temperature, and medium characteristics of the application environment, following three core principles:
potential matching, weather resistance matching, and strength matching.
Key industry-standard guidelines for material selection:
- Dry indoor environments: Carbon steel or low-alloy steel fasteners (Grade 4.8, 8.8) with basic electroplating for cost-effective general machinery and indoor assembly.
- Humid or mildly corrosive environments: 304 stainless steel, which forms a dense passive film due to 18% Cr + 8% Ni content. It remains corrosion-free in atmospheric environments with relative humidity ≤ 85%, ideal for home appliances and interior construction.
- Heavy corrosion / special media environments: 316L stainless steel (with Mo for chloride resistance), 2205 duplex stainless steel, titanium alloy, or Hastelloy. 316L resists mild acid and alkali solutions below 5%; 2205 duplex stainless steel has a Pitting Resistance Equivalent Number (PREN) ≥ 32, suitable for offshore platforms and chemical reactors.
- Extreme high/low temperature environments: High-temperature alloys for environments above 300°C; low-temperature toughness steel for below -40°C to prevent embrittlement and accelerated oxidation.
Critical technical indicator:
The standard electrode potential difference between connected metals must be ≤ 0.25V to avoid severe galvanic corrosion.
2. Professional Surface Treatment: Building Standardized Anti-Corrosion Barriers
For carbon steel and alloy steel substrates, surface treatments complying with GB/T 5267.1-2023 (electroplating) and GB/T 5267.2-2021 (non-electrolytic zinc flake coating) form protective layers.
Corrosion performance is quantified by neutral salt spray (NSS) test duration.
Technical note:
High-strength fasteners (tensile strength ≥ 1000 MPa) risk hydrogen embrittlement. Prefer non-electrolytic coatings such as Dacromet. If electroplated, mandatory de-embrittlement treatment at 200°C for 24h is required per GB/T 5267.1-2023.
Technical note:
3. Standardized Storage & Transportation: Blocking Corrosion Triggers
Corrosion during storage and transport mainly results from moisture, contact between dissimilar metals, and surface contamination.
Three core protocols apply:
1. Environment Control
- Storage environment: temperature 20±5°C, relative humidity ≤ 60%, with dehumidifiers and real-time monitoring.
- Packaging: vacuum-sealed bags + moisture-proof cartons + elevated pallets. Desiccant dosage ≥ 200g per cubic meter.
- Unused fasteners must be resealed within 4 hours after opening.
2. Isolation of Dissimilar Metals
- Separate storage by material; avoid direct contact between metals with potential difference > 0.25V (e.g., carbon steel & stainless steel, aluminum & copper).
- Use plastic or wooden racks; metal shelves must be galvanized or powder-coated.
3. Cleanliness & Protection
- Protect against rain and impact during transportation to avoid coating damage.
- Monthly surface cleaning with anhydrous ethanol to remove dust and oil.
4. Industry-Specific Anti-Corrosion Strategies
Wind & Nuclear Power
- Dacromet coating + 1000h salt spray requirement; torque retesting every 6 months.
- Automotive & Rail Transit
- Zinc-nickel plating for body; Dacromet for chassis; sealant applied at joints
- Chemical & Offshore
- 316L / 2205 duplex stainless steel + PTFE gaskets; monthly corrosion inspection.
- Electronics & Precision Instruments
- 304 stainless steel micro-fasteners + passivation + film protection; handle with powder-free gloves.
- Construction & Engineering Machinery
- Grade 10.9 high-strength Dacromet bolts + sealant; full anti-corrosion refurbishment every 1–2 years.
