Effects of Water Quality Parameters on the Corrosion of Galvanized Steel

Abstract

Jar tests and a circulating water system were used to evaluate the effect of water quality parameters, in particular the Langelier index (SI), on the corrosion of galvanized steel. Since waters with a positive SI were sometimes found to be at least as corrosive as waters with a negative SI, especially if the effect of dissolved oxygen was neglected, no definite relationship could be established between corrosion rate and SI. In both Gainesville, Fla., tap water and deionized water, corrosion was observed to be fastest in the pH range 5–6.5. A general mechanism for the formation of corrosion products is presented. Overall results suggest that the SI should be used only with caution in the practice of corrosion control and that prediction of a water's corrosivity should also consider the influence of other water quality parameters.