1.What are the limitations of ordinary color-coated steel plates at the seaside?
Insufficient corrosion resistance
The substrate of ordinary color steel plates is mostly ordinary cold-rolled steel or galvanized steel, and the coating is conventional polyester or silicon-modified polyester. Chloride ions in the seaside air will penetrate the tiny gaps in the coating and electrochemically corrode the substrate, causing the substrate to rust and the coating to bulge and fall off. ◦ Ordinary galvanized layers are quickly consumed in high-salt environments and lose their protective effect.
Poor weather resistance
The strong ultraviolet rays, high temperature and high humidity alternating environment at the seaside will accelerate the aging of the coating: the weathering period of ordinary PE coating is only 5-8 years, and it may fade and powder within 3 years at the seaside; the sealant at the joints is prone to aging and cracking, causing water leakage.
2.How to choose galvanized substrate?
Galvanized substrate: Choose high zinc layer galvanized sheet, or zinc aluminum magnesium alloy substrate.
Stainless steel substrate: For extreme high salt environment, 304 or 316 stainless steel substrate can be selected.
3.How to improve weather resistance and corrosion resistance?
Coating type: Fluorocarbon coating (PVDF) is preferred, its weather resistance (UV resistance, acid and alkali resistance) is 5-8 times that of ordinary PE coating, and its service life can reach 15-20 years in seaside environment; High weather resistance polyester (HDP) is the second choice, with a service life of 8-12 years.
Coating thickness: The coating thickness of the front side is ≥25μm, and the back side is ≥5μm. Thick coating can reduce the risk of chloride ion penetration.
4.How to reduce the risk of rust?
Sandwich panel joint treatment: Use hidden overlap structure (rather than exposed screw fixation) to prevent screw holes from becoming rust breakthroughs; the joints need to be sealed with weather-resistant sealant (such as silicone glue), and the thickness of the glue layer should be ≥3mm.
Edge treatment: The cutting edge of the board needs to be sealed with anti-corrosion (apply special anti-corrosion paint or silicone) to prevent the core material from absorbing moisture and causing edge corrosion.
5.What are the maintenance suggestions for seaside color steel plates?
Rinse the surface salt with fresh water at least 1-2 times a year to avoid long-term adhesion of chloride ions.
Check whether the coating is damaged. If scratches or bulges are found, repair them with special repair paint in time.
Replace aging sealants regularly to ensure that the joints are waterproof and sealed.