1 uniform corrosion. Corrosion of the metal surface makes the section evenly thin. Therefore, the annual average thickness loss value is commonly used as an indicator of corrosion performance (corrosion rate). Steel is generally uniformly corroded in the atmosphere.
2 pitting corrosion. The metal is corroded in dots and forms deep pits. The generation of pitting corrosion is related to the nature of the metal and the medium in which it is located. Pitting corrosion is prone to occur in media containing chloride salts. The maximum hole depth of pitting corrosion is often used as an indicator. Corrosion of pipelines often considers pitting problems.
3 galvanic corrosion. Corrosion caused by different potentials at the contact of different metals.
4 crevice corrosion. Localized corrosion of metal surfaces in the gaps or other concealed areas often occurs due to differences in the composition and concentration of the medium between the different parts.
5 stress corrosion. Under the action of corrosive medium and high tensile stress, the metal surface is corroded and spreads into microcracks inward, often leading to sudden breakage. This damage may occur in high-strength steel bars (steel wires) in concrete.