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Title: Hot corrosion burner rig testing of various commercial alloys

Conference ·
OSTI ID:696917
;  [1];  [2]
  1. Haynes International, Kokomo, IN (United States)
  2. Cornell Univ., Ithaca, NY (United States)

Hot corrosion is typically defined as the accelerated high temperature oxidation caused by a thin fused salt deposit in contact with the surface of a metallic material. When alloys used in air and land-base gas turbines experience hot corrosion, Na{sub 2}SO{sub 4} is usually the dominant salt found in the deposit due to the thermodynamic stability of this compound in the presence of sodium and sulfur in an oxidizing gas. In an effort to study the hot corrosion of several Fe- and Ni- base commercial wrought alloys in a gas turbine environment, a burner rig test program was executed. The study was conducted at 900 C (1650 F) and incorporated various test durations and two fuel sulfur contents (0.4 and 1.Owt%). Also, a synthetic sea salt was injected into the combustion zone of the burner rig, thereby maintaining a specific concentration of the salt in the combustion gas. Tests with the injection of 0 parts per million (ppm), 5 ppm, or 50 ppm salt were conducted. The principal constituents of the solution were NaCl, MgCl{sub 2},Na{sub 2}SO{sub 4}, CaCl{sub 2}, and KCl. In general, the Ni-base alloys tested exhibited superior hot corrosion resistance over the Fe-base alloys. When exposed to a 1000 hour test with the injection of 50 ppm salt, the Fe content of a Ni-22Cr-18Fe-9Mo alloy appeared to be detrimental to the hot corrosion resistance of this alloy when compared to a Ni-21Cr-9Mo alloy. The W content in a Ni-22Cr-14W alloy did not show a detrimental affect on the hot corrosion resistance of this material. Also, Fe- base alloys containing less than 25wt% Cr did not perform well in a 500 hour test burning fuel containing 1.0wt% sulfur and 50 ppm salt injected into the combustion zone. Reasons for the performance of the alloys are suggested to be the quality or protectiveness of the oxide scale grown on a given alloy, the composition of the oxide scale grown on a given alloy -- making the scale more or less susceptible to a synergistic hot corrosion attack, and/or the alloy composition in relation to its ability to resist attack by chloride salts.

OSTI ID:
696917
Report Number(s):
CONF-990401-; TRN: IM9946%%303
Resource Relation:
Conference: Corrosion 1999 conference, San Antonio, TX (United States), 25 Apr 1999; Other Information: DN: 1 CD-ROM. Operating Systems: Windows 3.1, `95, `98 and NT; Macintosh; and UNIX; PBD: 1999; Related Information: Is Part Of Corrosion 99: Proceedings; PB: [3500] p.
Country of Publication:
United States
Language:
English