Application of Extreme Value Statistics to Corrosion

Department of Materials Science and Processing, -Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565 JAPAN Application of extreme value stati'iiics to corrosion is rcvieweJ. It is cmpha sized that the concept of corroiiion probability is important for a quanlitalivc evaluatioti Of corrosion failure and its prediction, especially for localized corrosion. Extreme value statistics is quite useful for assessing the maximum pit depth and/or the minimum time for crack generation. The maximum pit depth depending on the stirface area can be evaluated hy using the Gumbel distribution with the concept of return period. A standardized procedure i.? proposed for estimating the maximum pit depth. Examples of corrosion failure analysis using extreme value statistics, which were reported mainly in Japan, arc shown. Accumulated experiences suggest thai an appropriate classification of data based on the corroiiion mechanism is reijuircd iKfore applying extreme value analysis.