Corrosion Tests at Elevated Temperatures and Pressures^★

The trend in the chemical industry is toward higher temperatures and pressures, conditions which are conducive to increased corrosion. In searching for appropriate materials for construction in these areas, tests were conducted on a number of metals and alloys, including refractory metals, nickel-base alloys and stainless steels, at elevated temperatures and pressures. Results were obtained at temperatures representing their normal boiling points, 190 C and 250 C, in solutions of sulfuric, hydrochloric, nitric and phosphoric acids over a wide range of concentrations. The tests showed that the refractory metals, tantalum, zirconium, molybdenum, tungsten, columbium, titanium and vanadium, are, in general, more resistant than the nickel-base alloys and stainless steels in these environments. The listing is the approximate decreasing order of resistance, from tantalum to vanadium. However, the selection of a material depends upon the environment and economics involved.