Solar power stations operate outdoors all year round, suffering from multiple corrosion factors including sunlight, temperature difference, rain, coastal salt spray and acid rain. Corroded fasteners, thread galling and torque attenuation will cause bracket loosening and module offset, shortening the 25-year design life of PV systems. Following the industry standard T/CPIA 0013—2019, solarfastener sorts out a complete classification of fastener materials, anti-corrosion indicators, standardized torque and installation protection solutions, covering ground PV, rooftop distributed PV, floating PV and coastal tidal flat power stations.
With 1000~1500 hours salt spray resistance and cost-effective performance, tensile strength reaches 700MPa. Suitable for inland mountain areas, household rooftop PV and inland industrial parks without strong chloride ions. Widely used for aluminum bracket connections, module clamp screws and small T-bolts. Not recommended for coastal or seawater evaporation zones, prone to pitting corrosion under long-term high salt fog.
Molybdenum alloy delivers superior chloride resistance with over 2000 hours salt spray resistance, the standard material for coastal, floating PV and chemical industrial parks. Higher mechanical strength for heavy-load tracking bracket connections, anchor bolts and high-humidity seaside areas, supporting 20-year maintenance-free outdoor service.
Zinc-aluminum flake coating achieves 1000-hour salt spray resistance at lower cost than stainless steel, no hydrogen embrittlement risk. Applied to main connections of galvanized steel brackets and temporary PV projects. Isolate stainless steel and carbon steel with nylon gaskets to avoid galvanic corrosion.
UV-modified PA66 nylon for PV plastic insulating clamps and battery module fixing, cutting conductive loops to prevent electric leakage. Only for auxiliary insulation fixing, cannot bear heavy structural loads.
1. Salt spray test follows GB/T 10125: inland projects require at least 1000 hours without red rust; coastal C5 corrosion grade needs over 2000 hours; 2. Anti-galling solution for stainless steel threads: SUS304/SUS316 tend to cold-weld during tightening. Apply molybdenum disulfide anti-seize grease and reduce torque by 20%~30%; 3. Galvanic corrosion prevention: Stainless steel, carbon steel and aluminum alloy shall not contact directly; EPDM rubber or nylon isolating washers are mandatory; 4. Surface treatment difference: Stainless steel relies on passive film for rust protection; carbon steel prefers Dacromet, ordinary electro-galvanizing is not recommended due to only 48-hour salt spray resistance.
1. M8 SUS304 bolt: 18~22N·m dry assembly; 14~17N·m with anti-seize grease; 2. M8 SUS316 bolt: 24~28N·m dry assembly; 19~22N·m with anti-seize grease; 3. M10 SUS304 bolt: 36~42N·m dry assembly; 29~34N·m with anti-seize grease; 4. M10 SUS316 bolt: 45~52N·m dry assembly; 36~42N·m with anti-seize grease;
Operation tips: Do not use air impact wrench for one-step locking; tighten twice step by step with torque wrench to reduce torque attenuation and bracket deformation.
Inland Mountain & Rooftop Distributed PV (C3 Mild Corrosion): Main SUS304 screws + Dacromet carbon steel anchors, ordinary nylon washers, 1000-hour salt spray grade; Coastal Tidal Flat & Floating PV (C5 Heavy Salt Spray): Full SUS316 A4-80 bolts with fluorocarbon isolating gaskets, over 2000-hour salt spray resistance, inspect thread corrosion quarterly; Chemical Parks & Acid Rain Zones: SUS316 stainless steel with PTFE coated threads for enhanced acid & alkali resistance; Household Insulated PV Modules: Aluminum clamps matched with UV-resistant nylon hex screws for insulation and leakage prevention.
1. Inspection cycle: Annual visual check for inland power stations, quarterly spot check on thread and washer corrosion for coastal stations; 2. Failure criteria: Replace fasteners immediately if pitting corrosion, loose threads or torque attenuation over 15% occurs; 3. One-stop supply: solarfastener provides full set PV fasteners including T-bolts, hex bolts, nylon lock nuts, spring washers, flat washers and isolating gaskets. Complete supporting delivery according to project drawings, with salt spray test reports and material quality certificates. Custom heavy-duty anti-corrosion non-standard fasteners available.