Prediction of Pitting Damage Functions for Condensing Heat Exchangers PDF Download

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Languages : en
Pages : 17

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Book Description
Pitting corrosion is a form of extremely localized attack resulting in rapid penetration into a metal substrate, and is one of the most destructive and insidious forms of corrosion that occurs in industrial systems. Traditionally, the damage function, i.e., the number of pits versus the pit depth, is measured experimentally, and the development of damage is described using empirical models. In general, the empirical models are successful because the distribution functions employed display great mathematical flexibility, but they require a significant database to achieve reliability. In fact, they are only really successful when the answer is known in advance. In this study, we developed a deterministic method for predicting localized corrosion damage functions for condensing heat exchangers. The method incorporates calculations for the composition of the condensed environment and the electrochemical corrosion potential of the alloy, and includes mechanistic treatments of the nucleation and the growth of pits. The role of the important environmental parameters are identified, such as the chloride concentration and the partial pressure of oxygen. Good agreement is observed between the predicted damage functions and the experimental data.