Alloy Ranking for Corrosion Resistance Laboratory Tests Versus Field Exposures Available to Purchase

This paper reviews the relative ranking of the corrosion resistance of stainless steels and nickel-base alloys. Laboratory rankings for pitting resistance were determined by measuring critical pitting temperatures in chloride-containing solutions with ferric ion additions. The rankings were compared to field test data obtained from locations in coal-fired power generating flue gas desulfurization systems and in various applications in the pulp and paper industry. Excellent correlation was found. Laboratory test results for measuring uniform corrosion resistance do not correlate well with uniform corrosion rates from field racks retrieved from a wide variety of industrial applications.