Large Steel Structure Corrosion and Steel Structures Corrosion Protection Considerations
Large steel structure construction in marine atmosphere, industrial atmospheric corrosion features:
Atmospheric environment of the steel structure from the sun, wind, rain and snow, frost and dew, and the function of temperature and humidity change by all the year round, including atmospheric oxygen and water is an important factor of outdoor steel structure
corrosion, electrochemical corrosion.
Industrial gases containing SO2, NO2, CI2, H2S, CO2 and NH3, although these ingredient content is very small, but the steel corrosion harm is not to be ignored, which had the greatest influence of SO2, CI2 can make the metal surface passivation film is destroyed.The acidic gases dissolve in water, acid rain formation, corrosion of metal facilities.
The characteristics of the Marine atmosphere is contains a lot of salt, mainly NaCI, salt particles falling on metal surface, due to its moisture absorption and increase the conductive effect of the liquid film and the CI - itself and has a strong corrosive, and thus increase the corrosion of the metal surface.Steel structure near the coast, the corrosion is more serious, its corrosion speed double inland is many times higher than that of the atmosphere.
Large steel structural steel structure anticorrosion
Large steel structures such as Bridges, television tower, tower, high-pressure lightning tower, the lighthouse in the sea, large reservoir sluice, water towers, offshore oil facilities, tank car, spherical tank, storage tank, oil tank, carbonization tower, heat exchanger, chimney, container, ship hulls, offshore platform steel structure, etc., are all under Marine atmospheric, industrial atmospheric corrosion environment for a long time.If you want to use for a long time, but not for large area maintenance, long-term protective coating for best before, the service life of up to 20 to 30 years, less maintenance, can obtain obvious economic benefit.
Large steel structure commonly used protection method
Steel structure commonly used spraying zinc or aluminum, aggravating corrosion coating form long-term anti-corrosion structure, or supporting heavy-duty coating coating protection.Metal zinc, aluminum has a great deal of characteristics of the resistance to atmospheric corrosion.On steel components spraying zinc or aluminum, zinc, aluminum, steel of the negative potential, and sacrificial anode protection so that the basic protected steel.Now with aluminum coating to prevent corrosion of industrial atmosphere, ocean, atmosphere, its characteristic is as follows:
(1) solid, coating aluminum coating and steel substrate, long life, good long-term economic benefits;
(2) the process flexible, suitable for important large and difficult maintenance of long-term protection of steel structure, site construction;
(3) spraying zinc or aluminum coating anticorrosive coating is closed, can greatly prolong the service life of coating, from the point of theory and practical application effect, spraying zinc or aluminum coating is the best bottom anticorrosive coatings.Metal spray coating and coating of anticorrosion coating of composite coating protective life more metal spray coating and anticorrosion coating protective layer between life longer, the sum of several times of life as a single coating layer.
Long-term anti-corrosion coatings composed of primer and intermediate paint and paint.
From long-term economic consideration, aluminum coating the most economical, but to invest big, construction good coating can be in 10 years without maintenance.Epoxy zinc rich primer + epoxy micaceous iron oxide intermediate paint and acrylic polyurethane long-term protection system has a better economy.