Atmospheric Corrosion
Atmospheric corrosion: Metal surfaces are affected by air humidity, pollutant gases, and dust. This leads to long-term oxidation that rusts the material.
Physical-Chemical Mechanism of Action
Atmospheric corrosion occurs from the reaction of metals with air humidity and pollutant gas molecules like carbon dioxide (CO2) or sulfur dioxide (SO2). These gases react on the metal surface, forming a moisture film. This film enables a continuous electrolytic reaction between the metal and the pollutant gases, leading to corrosion.
Metallurgical Relevance & Risks in Welding
Atmospheric corrosion can cause long-term rusting of metal surfaces exposed to air. This can shorten service life and reduce the material's mechanical properties. Weld areas are particularly vulnerable because they are often not fully protected and can easily be affected by corrosion.
Workshop Practice & Action Instructions
To prevent or limit atmospheric corrosion, metals should be treated before exposure to air. This can be done through suitable surface treatments like painting, galvanizing, or spray coating. In the workshop, it's important to thoroughly clean and protect weld areas after welding to avoid corrosion.