Sulfidation-resistant alloy for coal gasification service. Quarterly report, 1 September--30 November 1976
Austenitic stainless steels have been found to undergo a transition in sulfidation resistance with increasing hydrogen sulfide or decreasing water content in synthetic coal gasification environments. The limiting water and hydrogen sulfide contents for the formation of stable oxide scales on the surface have been determined for 310 stainless steel and Incoloy 800 at 1255/sup 0/K. Molten sulfide slags form on the surface beyond these limits. Alloys in the Fe--Al--Mn and Fe--Al--Mn--Cr systems have been screened for both cyclic air oxidation and sulfidation resistance. The addition of 2.5 to 5.0 percent Mn to Fe-base alloys with 8 to 12 percent Al results in excellent resistance to cyclic oxidation in air at 1255/sup 0/K. All Fe--Al--Mn alloys with 3 to 15 percent Al and 0 to 40 percent Mn have no resistance to sulfidation in the IITRI test gas at 1255/sup 0/K. Alloys in the Fe--Al--Cr--Mn system with 8 to 10 percent Al, 5 to 15 percent Cr, and 2.5 to 5 percent Mn have excellent resistance to both cyclic oxidation in air and the IITRI test gas atmosphere. A major laboratory testing and potential materials problem has been discovered in conducting simulated environmental tests. The sulfidizing potential of synthesized mixtures of H/sub 2/, H/sub 2/O, CO, CO/sub 2/, CH/sub 4/, H/sub 2/S, and NH/sub 3/ is increased tremendously when the gas mixture is equilibrated at 1255/sup 0/K. The formation of new species such as S/sub 2/ vapor, COS, and O/sub 2/ significantly change the surface reactions on ferritic Fe--Cr--Al, Fe--Cr--Al--Mn, and austenitic Fe--Cr--Ni alloys. The Fe--Cr--Al alloys, including Kanthal (Fe--26Cr--5Al) which were not penetrated by sulfur in non-equilibrium gas mixtures were attacked severely and formed thick sulfide scales in equilibrated gases in less than 24 h at 1172/sup 0/K. They were sulfidized completely in 24 h at 1255/sup 0/K. The effect on austenitic steel was observed with Type 304 stainless but not with the more highly alloyed 310.
- Research Organization:
- Lockheed Missiles and Space Co., Palo Alto, CA (USA). Lockheed Palo Alto Research Lab.
- DOE Contract Number:
- EX-76-C-01-2299
- OSTI ID:
- 7109266
- Report Number(s):
- FE-2299-6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
AMMONIA
CORROSIVE EFFECTS
CARBON MONOXIDE
COAL GASIFICATION PLANTS
MATERIALS TESTING
HYDROGEN
CORROSION
HYDROGEN SULFIDES
METHANE
WATER VAPOR
ALUMINIUM ALLOYS
INCOLOY 800
STAINLESS STEEL-310
IRON BASE ALLOYS
MANGANESE ALLOYS
ALUMINIUM CARBIDES
IRON CARBIDES
ALUMINIUM NITRIDES
IRON NITRIDES
CHROMIUM ALLOYS
MIXTURES
VERY HIGH TEMPERATURE
ALKANES
ALLOYS
ALUMINIUM COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRYOGENIC FLUIDS
DISPERSIONS
ELEMENTS
FLUIDS
GASES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INCOLOY ALLOYS
INDUSTRIAL PLANTS
IRON ALLOYS
IRON COMPOUNDS
MATERIALS
NICKEL ALLOYS
NITRIDES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
STAINLESS STEELS
STEELS
SULFIDES
SULFUR COMPOUNDS
TESTING
TRANSITION ELEMENT COMPOUNDS
VAPORS
010404* - Coal
Lignite
& Peat- Gasification
360105 - Metals & Alloys- Corrosion & Erosion