High-Temperature Corrosion of Incoloy Alloy 800 in N2/H2S Gas

The nickel-iron-chromium-based alloy, Incoloy alloy 800, was corroded at 600, 700 and 800 °C for 10-70 h under 1 atm of total pressure in three different atmospheres, viz., 1 atm of N2, N2/H2O, and N2/H2O/H2S-mixed gases. The corrosion rates always increased with addition of H2O and, much more seriously, with the addition of H2S gas. In N2 and N2/H2O gases, oxidation prevailed. In N2/H2O/H2S gases, sulfidation dominated. The corrosion resistance increased in the T22 steel displayed better resistance to oxidation and sulfidation than Fe-2Mn-0.5Si steel, owing to the presence of Cr. Strong enrichment of Cr and the presence of Ni and Fe were noticeable in the inner scale. Chromium sulfidized to FeCr2S4 in N2/H2O/H2S gases, which was responsible for the enhanced sulfidation resistance of T22 compared with Fe-2.0Mn-0.5Si steel.

INCOLOY ALLOY 945 AND 945X

Incoloy Alloy 945 is a nickel-base precipitation-strengthened alloy that provides 860 MPa (125 ksi) minimum yield strength and an excellent combination of ductility and impact strength. The nickel content is sufficient to provide protection against chloride-ion stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-666. Producer or source: Special Metals Corporation. Originally published December 2008, revised April 2014.

INCOLOY ALLOY 25-6HN

Incoloy alloy 25-6HN is a 6% Mo superaustenitic stainless steel. It offers an excellent combination of strength, ductility, and resistance to corrosion by a variety of media at an economical price. It is readily formed and welded. The properties of the alloy are enhanced by its content of nitrogen. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: SS-1056. Producer or source: Special Metals Corporation.