Short Term Atmospheric Corrosion of Low Carbon Steel

摘要

Atmospheric corrosion tests have previously been performed in Mauritius through the outdoor exposure of low carbon steel. Results have shown that the corrosion degradation of the metal follows the bilogarithmic law except for the first three months of the atmospheric exposure. Further atmospheric corrosion tests were therefore performed for this very short term to analyze this period of atmospheric exposure. Low carbon steel was, therefore, exposed outdoors according to ISO 8565. They were removed after 1, 2 and 3 months of exposure in sets of three. The Weight Loss Method was used to determine the corrosion loss. The Point Counting Method was also used to determine the extent of the atmospheric corrosion attack in the first months of exposure. The Weight Loss Method showed that for the first three months the corrosion loss is linearly related to the time of exposure. The Point Counting Method, which is not commonly used in corrosion testing, showed that the surface degradation of the metal varies linearly with time of exposure, thus confirming the results of the Weight Loss Method. This type of behavior occurs, most probably, because the atmosphere attacks the metal directly at the start of the exposure period and this leads to a high rate of corrosion.