Low alloy steel corrosion resistance

- Apr 05, 2019-

When low-alloy high-strength steels are used, it is desirable to take advantage of their high strength and use thinner sections, not only to save weight but also to be as economical as possible. However, the corrosion factor must be fully considered. The thinner the steel section, the more attention should be paid to corrosion protection. The corrosion protection of any steel structure is generally achieved by applying an anti-corrosion layer to a suitably prepared surface and protecting the anti-corrosion layer. Some low-alloy high-strength steels have good atmospheric corrosion resistance, which not only can improve the effect of anti-corrosion coatings, but also take appropriate precautions in some cases and even expose them to the atmosphere without coating. . No material is resistant to corrosion conditions that may be imagined. The atmospheric corrosion resistance of low-alloy high-strength steels varies with the composition and content of alloying elements that have the greatest effect on corrosion resistance. The elements that improve atmospheric corrosion resistance are copper, phosphorus, silicon, chromium, nickel and molybdenum.

The excellent atmospheric corrosion resistance of some low-alloy high-strength steels has led to the formation of new concepts for structural design of buildings, bridges, etc., that is, these structures are constructed using exposed components of appropriate low-alloy high-strength steel. In the normal exposure to the atmosphere, bare steel forms a tight protective oxide film during the first few months of atmospheric corrosion. Sometimes the architect chooses a bare steel structure because he wants to have a uniform atmospheric oxidation appearance on the steel surface, and sometimes to save the protective layer for economical purposes. The use of these low-alloy high-strength steels under bare conditions must be designed in such a way that the surface of the steel cannot be wet for long periods of time, and special attention should be paid to the special atmospheric environment to ensure that the corrosion rate of the steel is allowed under these conditions. For example, under strong chemical or industrial flue gas conditions, it is obviously not suitable. To verify if a bare steel structure can be used in certain environments. The atmospheric environment needs to be measured and even a bare test is required.