1.What are the core environmental parameters that need to be controlled?
Ambient humidity: should be ≤60% RH, when it is >70%, the zinc layer will continue to electrolyze, and white rust (basic zinc carbonate) will be generated in 72 hours.
Temperature fluctuation: should be between 10 and 35°C, and the drastic temperature difference will cause condensation (dew point temperature difference ≥3°C is dangerous), which will accelerate electrochemical corrosion.
Air pollutants: Cl⁻ adheres to form electrolyte, and SO₂ generates sulfuric acid to accelerate corrosion (the rate is increased by 10 times).
Light intensity: UV radiation destroys the passivation film on the surface of the zinc layer (especially the new Zn-Al-Mg coating)
2.What is the ground handling during warehousing?
It is absolutely forbidden to directly contact the cement floor (capillary absorption).
Dry wooden pallets must be used (moisture content <18%).
Pallet height ≥150mm (to prevent water accumulation and moisture in the rainy season).
Wood must be treated with mildew prevention (soaked in copper, chromium and arsenic solution).
3.How to deal with the rainy season/high humidity environment?
Arrange calcium chloride rotary dehumidifier in the warehouse (humidity setting ≤55%)
Place vapor phase anti-rust bags (VCI content ≥30g/m³) on each pile
Weekly check the zinc layer status: use 5% silver nitrate solution for drip test (immediately deal with white precipitate)
4.What precautions should be taken to prevent salt spray environment in coastal areas?
The packaging is vacuum sealed with aluminum-plastic composite film (oxygen permeability <0.5cm³/m²·day)
Spray sodium benzoate corrosion inhibitor (concentration 8~10%) before storage
Flush the surface salt with deionized water every month (conductivity ≤10μS/cm)
5.What are the early warning signs of quality deterioration?
Initial appearance of white rust: white floccules appear locally (use a hard-bristled brush to remove with 10% acetic acid solution)
Dark zinc flowers: surface gloss decreases by >30% (indicating damage to the passivation film)
Condensation drops: liquid water appears on the elbow surface (rust will occur within 24 hours)
Chloride ion crystallization: white salt crystals appear on the surface (use an ethanol cotton swab to wipe off)