Corrosion behaviour of sub-zero chilled cast iron

Abstract

This paper describes the results obtained and the deductions made from a series of corrosion experiments involving sub-zero chilled (using liquid nitrogen) cast iron containing 1.5% Cu and of chromium contents ranging from 0.0% to 0.2%. By using copper chills of different thicknesses the effect on corrosion of varying the chill rate was also examined. The corrosion tests employed were the weight-loss method according to ASTM G 67-80 standards. The microstructures of the corrosion products were also examined. Corrosion resistance was found to increase significantly with increase in chromium content. Nevertheless, even with high chromium content, some pitting was detected in the initial stages of most of the tests. Generally, corrosion attack was found to be most severe during the initial stage of each test but it invariably decreased to a very low value in the later stages, probably due to the formation of an adherent protective layer on the metal surface. © 1994.