Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings

Technical Report · Thu Aug 01 00:00:00 EDT 1991

DOI:https://doi.org/10.2172/5767769· OSTI ID:5767769

Van Weele, S ^[1]

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1. Foster Wheeler Development Corp., Livingston, NJ (United States)

Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Foster Wheeler Development Corp., Livingston, NJ (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5767769
• Report Number(s): ORNL/Sub-89-SA187/02; ON: DE92008500
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALI METAL COMPOUNDS
CORROSIVE EFFECTS
ALLOYS
TESTING
IRON SULFATES
ALUMINIUM
ASHES
BOILERS
CHROMIUM
CLADDING
COAL
FLUE GAS
NICKEL
PROGRESS REPORT
SIMULATION
STAINLESS STEELS
CARBONACEOUS MATERIALS
COMBUSTION PRODUCTS
DEPOSITION
DOCUMENT TYPES
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASEOUS WASTES
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
IRON COMPOUNDS
MATERIALS
METALS
OXYGEN COMPOUNDS
RESIDUES
STEELS
SULFATES
SULFUR COMPOUNDS
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WASTES
360105* - Metals & Alloys- Corrosion & Erosion