1.How to deal with low temperature environment?
Increase the coating thickness: In low temperature and high humidity scenarios (such as cold storage and refrigerated trucks), the zinc layer thickness needs to be increased to ≥200 g/m² to slow down the speed at which the zinc layer is penetrated by condensed water.
Composite passivation treatment: Use chromium-free passivation + organic sealant (such as silane treatment) to form a hydrophobic film on the surface of the zinc layer to reduce water adsorption.
Structural drainage design: Avoid structures that are prone to water accumulation, such as grooves and dead corners, and set a drainage slope of ≥3% to reduce condensation accumulation.
2.How to deal with it under normal temperature environment?
Standard passivation process optimization: Chromate passivation (such as trivalent chromium) or chromium-free passivation is used in conventional atmospheric environments, and the salt spray test corrosion resistance can reach 72-96 hours without white rust.
Comparison: Unpassivated DX51D is prone to white rust within 5 years in an indoor environment with a humidity of more than 60%; after passivation, it can be extended to 8-10 years.
Light oiling protection: When storing or transporting for a short period of time, the surface is coated with mineral oil or anti-rust grease to isolate oxygen and moisture.
3.How to deal with high temperature environment?
Upgraded coating material: Zinc-aluminum-magnesium coating (such as DX53D) is used in high-temperature industrial scenes (such as ovens and flues). Its aluminum-magnesium alloy layer forms a dense oxide at high temperatures, and its corrosion resistance is 2-5 times that of ordinary galvanizing, and its temperature resistance can reach 300°C.
High-temperature resistant coating coverage: The surface of the galvanized layer is coated with silicone paint or ceramic paint, which can withstand temperatures of up to 250-400°C and isolate acidic gases.
4.How to manage temperature and humidity together?
High temperature and high humidity scenario: Install ventilation and dehumidification systems in industrial plants to control humidity below 60% to reduce the probability of electrolyte formation.
Low temperature salt spray scenario: In coastal or road deicing areas, adopt a sealed structure design (such as changing bolt connections to welding) to reduce the intrusion of chloride ions into gaps.
5.How to perform regular maintenance?
High temperature environment inspection: Check the integrity of the oxide film on the surface of the galvanized layer every year, repair the cracks and peeling with zinc-rich paint (zinc content ≥ 90%), and restore the sacrificial anode protection.
Low temperature and humid environment inspection: Clean the condensation water accumulation area every quarter, clean the parts with white rust with dilute chromic acid solution (5% concentration), and then apply rust inhibitor.
Install corrosion monitoring sensors (such as electrochemical impedance sensors) to monitor the changes in the thickness of the zinc layer in real time. When the remaining thickness of the zinc layer is detected to be less than 50%, a maintenance reminder is triggered.