Résistance à la corrosion des fontes alliées

Corrosion resistance of alloy cast irons

Ingénieur à la Division des Fontes, Centre Technique des Industries de la Fonderie.

Abstract

Owing to their relatively high alloy content, alloy cast irons often exhibit a high degree of corrosion resistance in many mediums. Nevertheless, it is necessary to know which kind of iron can be used in a definite medium. It seemed, therefore, interesting to collect information on this subject. It is the purpose of our paper.

A large addition of nickel to cast iron produces materials with stable austenitic matrix which, being more noble than the matrix of unalloyed grey irons, gives very good corrosion resistance in most applications.

High-chromium irons also have good corrosion-resistant properties due to the superficial formation of an impervious chromium oxide film. So, these irons are most useful in mediums containing a large supply of oxygen or oxidizing agents.

The corrosion resistance developed by high-silicon alloys is due to the formation of a corrosion-resistant film containing a large amount of silica. These irons can withstand attacks from a very wide range of mediums, indeed few ions can penetrate this silica film.