1.What is the core reason?
Cold-rolled coils have a clean, highly reactive surface, making them extremely sensitive to chemical contamination even with rust-preventive oil protection.
Direct chemical reactions: Acids, alkalis, and other chemicals directly corrode the steel surface, damaging its metallic structure and protective layer.
Electrochemical corrosion: Salts (such as chlorides) absorb moisture and form electrolytes, triggering a "galvanic cell reaction," which exponentially increases the corrosion rate, far exceeding that of ordinary rust.
Hidden damage: Certain volatile chemicals (such as acid mist and ammonia) can cause extensive pitting or discoloration through airborne diffusion, seemingly without direct contact, and this damage is often difficult to repair.
2.What specific categories of chemicals should be avoided?
Acids: Hydrochloric acid, sulfuric acid, nitric acid, and their volatile gases.
Alkalis: Caustic soda, ammonia, etc.
Salts: Sodium chloride (table salt), ammonium chloride, etc. (especially dangerous, commonly found in de-icing agents, fertilizers, and sweat stains).
Oxidizing agents: Bleaching agents, some chemical raw materials.
Organic solvents: May dissolve surface rust-preventive oil, exposing metal.
3.Is absolute partitioning required?
Establish a separate, enclosed "clean steel storage area."
Sharing warehouse space or adjacent storage with any chemicals (including raw materials, semi-finished products, and waste) is strictly prohibited.
In the case of a comprehensive logistics park, cold-rolled coil warehouses should maintain a sufficient safe distance from chemical warehouses and be located upwind of them.
4.How can the environment and processes be controlled?
Clean Transportation: Handling vehicles, forklifts, shelves, etc., must be free of chemical residue.
Intact Packaging: Maintain the integrity of original rust-proof packaging (film, paper); repair any damage immediately.
Personnel and Tools: Wearing work clothes or gloves that have come into contact with chemicals is strictly prohibited. Use dedicated cleaning tools.
Clear Labeling: Clearly label the warehouse area with warnings such as "Chemicals Prohibited".
5.What are the supporting measures?
Control warehouse temperature and humidity (relative humidity recommended ≤60%) to reduce the risk of condensation.
Conduct regular inspections to check for cross-contamination risks or early rust.