Resistance of Kh17N2 and SN3 steels to corrosion and corrosion fatigue

Abstract

1. SN3 steel has a higher corrosion resistance in corrosive media than Kh17N2 steel. Thus, the corrosion resistance of SN3 steel in a 53% sulfuric acid solution (determined by the volume of hydrogen evolved per unit time) is 2.5 times higher than that of Kh17N2 steel. 2. The fatigue limit of SN3 steel in air is 10% higher than that of Kh17N2 steel. 3. The decrease in the fatigue resistance of both steels in 3% NaCl solution with respect to that in air is the same. The corrosion fatigue limit after 2·107 cycles is about one-half that of the fatigue limit in air for both steels. 4. We confirmed the conclusion that there is not direct relationship between the corrosion resistance and corrosion fatigue resistance of metals, since the two steels have very different corrosion resistances, while the decrease of their corrosion fatigue resistance (in aggressive media as compared to air) is the same. 5. SN3 steel is preferable to Kh17N2 steel as a structural material for compressor blades operating under corrosive conditions. However, its corrosion fatigue resistance is too low for use without a protective coating. 6. Coatings of No. 302 insulating lacquer increase the corrosion fatigue resistance of both steels in 3% NaCl solution 1.5 times.