AWWA JAW56673

Cavitation erosion can create problems for water supply systems by causing materials failure in pipes and pipe accessories, especially in regions such as Hong Kong, where water must be supplied to high-rise buildings under high water pressure. This research project investigated the cavitation erosion and corrosion behaviors of materials - copper, brass, bronze, cast iron, and stainless steel - commonly used in Hong Kong cold water supply systems. The cavitation erosion resistance of the various materials was ranked, and the relative significance of erosion-corrosion synergism was evaluated. In both tap water and deionized water, stainless steel outperformed other materials in resistance to cavitation erosion. The synergism of corrosion and erosion had a significant effect on materials, contributing to nearly 79% of the overall damage rate in cast iron and to 4.7% in stainless steel. Based on their findings, the authors also developed a simple formula for estimating the fractional increase in metal concentration attributable to cavitation erosion. Water supply systems, especially those in which cavitation is likely to occur, should consider both mechanical and corrosion properties in the selection and development of materials. Cavitation erosion must be taken into account, not only because of its damaging effects on susceptible parts but also because of the additional contamination it induces. Includes 31 references, tables, figures.