Abstract
Abstract Metallurgical examinations were conducted on a set of damaged high-alloy (Type 310H [UNS S31009] stainless steel and Alloy 625 [UNS N66250] weld overlay) superheater tubes removed from a coastal fluidized bed biomass power boiler, to better understand the degradation mode. Active oxidation (gas-solid reaction occurring underneath the chloride-containing fireside deposit) was found to be the mechanism responsible for the significant loss in tube wall thickness observed on damaged superheater tubes. There exists a complex, poorly-understood synergy between the critical factors that affect active oxidation, primarily tube temperature and the supply of reactants in the flue gas, namely, sodium chloride (NaCl), sulfur dioxide (SO2), and water vapor (H2O). Overall ranking in terms of increasing corrosion resistance to active oxidation follows the expected trend: T22 < SS310H < A625WO. Despite the favorable ranking, the Alloy 625 weld overlay can corrode by active oxidation at an appreciable rate (0.45 ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
