Corrosion resistance of stainless steels in fresh and chlorinated water

Cement, galvanised steel, coated carbon steel and cast iron are commonly used for large pipes in potable distribution networks. Even if these materials have been in operation for decades, they are used to suffer from external corrosion by soils or internal corrosion by water. To solve these problems, coatings, electrochemical protection or/and monitoring of the water chemistry have often to be applied. Due to their superior corrosion resistance, stainless steels may be used without any of these protection systems, which lead to easier installation, safer operation and better water quality. In order to study the influence of chlorination biocide treatment on the corrosion resistance of various stainless steels, electrochemical investigations have been made in natural fresh water and chlorinated water with a close control of the water chemistry. The results demonstrate that duplex stainless steels may be good candidate to manufacture fresh and drinking water pipes.