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Title: Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 650?C

Abstract

No abstract prepared.

Authors:
 [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Temperature Materials Laboratory
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
930874
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: IGTI TurboExpo 2007, Montreal, Canada, 20070514, 20070517
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; OXIDATION; STAINLESS STEELS; TEMPERATURE DEPENDENCE

Citation Formats

Matthews, Wendy J, More, Karren Leslie, and Walker, Larry R. Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 650?C. United States: N. p., 2007. Web.
Matthews, Wendy J, More, Karren Leslie, & Walker, Larry R. Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 650?C. United States.
Matthews, Wendy J, More, Karren Leslie, and Walker, Larry R. Mon . "Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 650?C". United States. doi:.
@article{osti_930874,
title = {Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 650?C},
author = {Matthews, Wendy J and More, Karren Leslie and Walker, Larry R},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
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  • A surface treatment was applied to the surface of Type 347 stainless steel to enhance oxidation resistance. The treatment consisted of dip coating coupons in a CeO2 and halide activator slurry, followed by a thermal treatment at 900C in an inert atmosphere for 12 hours. Cyclical oxidation tests were conducted at 800C in either dry air or air+3%H2O. In dry air, the treatment reduced the oxidation rate (reduced the magnitude of weight gain) of the alloy by a factor of three. Protective chromium based oxide and spinel ((Mn,Cr)3O4 and (Cr,Fe)2O3) phases formed on the surface of the untreated and treatedmore » alloy. More significantly, the treatment suppressed the oxide scale spallation that occurred upon cyclical exposure of this alloy to moist air. In moist air, less protective chromite (FeCr2O4), magnetite (Fe+2Fe2+3O4), and hematite (Fe2O3) formed as oxide products on the surface of the base alloy. The treated alloy did not spall during exposure to moist air, and interestingly, the treated alloy possessed similar oxidation rates (magnitude of weight gain) in both moist and dry air. The same protective chromium based oxide and spinel ((Mn,Cr)3O4 and (Cr,Fe)2O3) phases formed on the surface of the treated alloy exposed to both moist and dry air. In the aggressive moist environment, the Ce surface treatment suppressed the formation of less protective iron-oxides, and concomitant oxide scale spallation during thermal cycling.« less
  • Primary surface recuperators (PSRs) are compact heat-exchangers made from thin-foil type 347 austenitic stainless steel, which boost the efficiency of land-based gas turbine engines. Solar Turbines uses foil folded into a unique corrugated pattern to maximize the primary surface area for efficient heat transfer between hot exhaust gas on one side, and the compressor discharge air on the other side of the foil. Allegheny-Ludlum produces 0.003 - 0.0035 in. thick foil for a range of current turbine engines using PSRs that operate at up to 660 degrees C. Laboratory-scale processing modification experiments recently have demonstrated that dramatic improvements can bemore » achieved in the creep resistance of such typical 347 stainless steel foils. The modified processing enables fine NbC carbide precipitates to develop during creep at 650-700 degrees C, which provides strength even with a fine grain size. Such improved creep-resistance is necessary for advanced turbine systems that will demand greater materials performance and reliability at higher operating conditions. The next challenges are to better understand the nature of the improved creep resistance in these 347 stainless steel foil, and to achieve similar improvements with scale-up to commercial foil production.« less
  • Type 316 stainless steel in the 20%-cold-worked condition was irradiated in the High Flux Isotope Reactor (HFIR) and subsequently tested in fatigue. The specimens were irradiated at 550/sup 0/C to damage levels of 8 to 12 dpa and transmutation helium levels of 300 to 500 at. ppM. Fatigue testing at 650/sup 0/C revealed that cyclic life was not significantly affected by the irradiation. However, unlike the results of tests of the same material at 550/sup 0/C, no endurance limit was observed. The absence of an endurance limit is interpreted in terms of thermal creep.