Features heavy-duty steel corrosion protection methods analysis

Features heavy-duty steel corrosion protection methods analysis

     Large steel structure such as a bridge, tower, high voltage junction tower, lightning tower, sea lighthouse, a large reservoir gates, water towers, offshore oil facilities, tankers, tank, tank, tank, carbonation towers, heat exchangers, chimneys, container , ship hull, steel and other offshore platforms, are long-term in the marine atmosphere, atmospheric corrosion in industrial environments. To long-term use, but not a large area maintenance, long-lasting protective coating is best for the former life of up to 20-30 years, less maintenance costs, availability of significant economic benefits.

     A large steel structure in the marine atmosphere, the atmospheric corrosion of steel industry characteristics of the atmospheric environment affected by temperature and humidity changes the role of the sun, wind, rain, snow, frost, and throughout the year, in which atmospheric oxygen and moisture are important factors that cause corrosion outdoor steel structure, causing electrochemical corrosion. Industrial gas containing SO2, CO2, NO2, CI2, H2S and NH3, etc., although the content of these ingredients is small, but the steel corrosion hazards are not to be ignored, where the greatest impact SO2, CI2 make metal surface passivation film was destruction. These gases are dissolved in the water is acidic, the formation of acid rain, corrosion of metal facilities. Marine atmosphere is characterized by containing a lot of salt, mainly NaCI, salt particles settling on the metal surface, due to its absorption of moisture and increases the effect of surface conductive film while CI- itself has a strong corrosion resistance, and thus increased corrosion of metal surfaces. Steel from the coast nearer the more serious corrosion, corrosion rate many times higher double inland atmosphere.

     2, large steel structure steel protection methods commonly used spray sprayed zinc or aluminum, increased corrosion coatings constitute long-term preservation structure, or with matching heavy-duty protective paint coating. Zinc, aluminum has great resistance to atmospheric corrosion properties. Zinc spray or sprayed on steel structures aluminum, zinc, aluminum and steel to form a negative potential role of sacrificial anode protection so that the basic iron and steel have been protected. Sprayed aluminum coatings currently used to prevent industrial atmosphere, ocean atmospheric corrosion, which is characterized as follows:

     (1) sprayed aluminum coating and steel substrate binding solid, long coating life, long-term economic good;

     (2) technology and flexible, suitable for large-scale and long-term protection is important hard steel structure maintenance, field construction;

     (3) zinc spray or sprayed aluminum coating plus anti-corrosion coatings closed, can significantly extend the life of the coating, from the effects of the theoretical and practical point of view, sprayed zinc or aluminum spray coating is the best anti-corrosion coating layer. Metal coating layer and anti-corrosion coating composite coating protective coating life much longer than the metal coating layer and the protective layer of anti-corrosion coatings of both life and for the life of a single layer of protective paint several times. Heavy-duty long-lasting coating consists of a primer, intermediate coat and topcoat. From the long-term economic considerations, sprayed aluminum coating the most economical, but a one-time investment, good construction coatings can be in 10 years without maintenance. Epoxy zinc-rich primer + epoxy intermediate coat of iron and acrylic polyurethane lasting protection system has better economy.