INFLUENCE OF ENVIRONMENTAL FACTORS ON THE EARLY CORROSION OF STEEL IN COASTAL SEAWATER

This paper reports on some early observations in a more extensive field programme aimed at elucidating basic in-situ immersion corrosion behaviour characteristics for mild and low alloy steel exposed in coastal seawater regions. Five sites are described - two in Newcastle Harbour and three in Lake Macquarie (two in the entrance and one in Fennel Bay). Results are described for coupons recovered after one, three and six months exposure. Overall corrosion rates for the six months were found to be in the range 150 - 300 micrometres/year. Seasonal factors such as rainfall appeared to have a significant influence on the corrosion behaviour, particularly for the specimens at Fennel Bay. For the present observations, corrosion rates were found to increase with salinity, dissolved oxygen and water velocity but reduced with increasing biofouling. These results are not inconsistent with those previously reported - the present investigation is an attempt to obtain results systematically. (a) For the covering entry of this conference, please see IRRD abstract no. E200447.