Durability of metallic materials

The main form of corrosion of building metals

① Uniform corrosion. The corrosion of the metal surface makes the section uniformly thin. Therefore, commonly used annual average thickness loss value as an indicator of corrosion performance (corrosion rate). Steel in the atmosphere is generally uniform corrosion.

② hole corrosion. Metal corrosion is pitting and the formation of deep pits. Hole corrosion is generated with the nature of the metal and the media in which it is related. In the media containing chlorine salts are prone to pore corrosion. Hole corrosion is often used as the maximum hole depth as an assessment index. The corrosion of the pipeline to consider more hole corrosion.

③ electric couple corrosion. The contact of different metals, because of the different potential and corrosion.

④ crevice corrosion. Metal surface in the crevice or other hidden areas often occur due to the difference between different parts of the media components and concentrations caused by the local corrosion.

⑤ stress corrosion. In the corrosive medium and higher tensile stress together, the metal surface corrosion and inward expansion into micro-cracking, often leading to sudden breakage. Concrete in the high-strength reinforcement (steel wire) may occur this damage.