Engine Testing of an Advanced Alloy for Microturbine Primary Surface Recuperators

2005 ◽  
Author(s):  
Wendy J. Matthews ◽  
Terry Bartel ◽  
Dwaine L. Klarstrom ◽  
Larry R. Walker
Keyword(s):  
Steady State ◽  
Oxide Scale ◽  
Engine Test ◽  
Test Results ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Cyclic Operation ◽  
Engine Testing

HAYNES® alloy HR-120® has been identified as a potential alloy for the manufacture of primary surface recuperators. Primary surface recuperator components have been manufactured from HR-120, and actual microturbine testing is on going. Initial engine test results indicate the formation of a protective oxide scale that is resistant to both steady-state and cyclic operation with no evidence of accelerated attack, and which is likely to meet or exceed the desired 80,000 hour component life.

Primary Surface Recuperator Alloy Oxidation: A Comparison of Accelerated Engine Testing to Field Operation

2010 ◽  
Author(s):  
Wendy J. Matthews ◽  
Karren L. More ◽  
Larry R. Walker
Keyword(s):  
Steady State ◽  
Oxide Scale ◽  
National Laboratory ◽  
Normal Operation ◽  
Protective Oxide ◽  
Oak Ridge ◽  
Alloy Oxidation ◽  
Test Engine ◽  
Engine Testing

The Capstone C65 MicroTurbine Primary Surface Recuperator (PSR) core has been manufactured from Haynes alloy HR-120 since 2005. When exposed to the harsh operating environment of the microturbine PSR, HR-120 forms a protective oxide scale that is resistant to the effects of the water vapor present in the exhaust gas. Long-term accelerated microturbine testing, with samples in a modified PSR with a removable aft dome, is on-going at an elevated Turbine Exit Temperature (TET) ∼100°F higher than normal operation. The elevated TET test engine is operated at steady state conditions and the engine is shut down at pre-determined intervals for sample removal. Material characterization of the elevated TET samples has been carried out by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. The surface oxide scale formation and associated alloy compositional changes have been evaluated for elevated TET samples with operating lives ranging from ∼1,800 – ∼26,500 hours. In addition, field operated HR-120 recuperators have been sectioned and samples have been evaluated for operating lives ranging from ∼5,500 – ∼18,000 hours. Results from the microstructural and compositional analyses of both the long-term steady-state elevated TET HR-120 samples, and the field operated HR-120 recuperator samples, will be presented and compared.

Primary Surface Recuperator Alloy Oxidation: A Comparison of Accelerated Engine Testing to Field Operation

2010 ◽  
Vol 133 (4) ◽  
Author(s):  
Wendy J. Matthews ◽  
Karren L. More ◽  
Larry R. Walker
Keyword(s):  
Steady State ◽  
Oxide Scale ◽  
National Laboratory ◽  
Normal Operation ◽  
Protective Oxide ◽  
Oak Ridge ◽  
Alloy Oxidation ◽  
Test Engine ◽  
Engine Testing

The Capstone C65 Microturbine primary surface recuperator (PSR) core has been manufactured from Haynes alloy HR-120 since 2005 (Microturbine is a registered trademark of Capstone Turbine Corporation; Haynes and HR-120 are trademarks of Haynes International, Inc.). When exposed to the harsh operating environment of the microturbine PSR, HR-120 forms a protective oxide scale that is resistant to the effects of the water vapor present in the exhaust gas. Long-term accelerated microturbine testing with samples in a modified PSR with a removable aft dome is ongoing at an elevated turbine exit temperature (TET) ∼100°F higher than normal operation. The elevated TET test engine is operated at steady-state conditions, and the engine is shut down at predetermined intervals for sample removal. Material characterization of the elevated TET samples has been carried out by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. The surface oxide scale formation and associated alloy compositional changes have been evaluated for elevated TET samples with operating lives ranging from ∼1800 h to ∼26,500 h. In addition, field-operated HR-120 recuperators have been sectioned and samples have been evaluated for operating lives ranging from ∼5500 h to ∼18,000 h. Results from the microstructural and compositional analyses of both the long-term steady-state elevated TET HR-120 samples and the field-operated HR-120 recuperator samples will be presented and compared.

Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

1970 ◽  
Vol 28 ◽  
pp. 510-511
Author(s):  
L. P. Lemaire ◽  
D. E. Fornwalt ◽  
F. S. Pettit ◽  
B. H. Kear
Keyword(s):  
Oxide Scale ◽  
Oxidation Process ◽  
Short Circuit ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Thin Oxide Films ◽  
Diffusion Paths ◽  
Oxidation Resistant ◽  
Structural Imperfections ◽  
Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

The importance of interfacial chemistry in protective oxide scale adherence

1988 ◽  
Vol 30 (3-4) ◽  
pp. 259-266 ◽  
Author(s):  
J. G. Smeggil ◽  
N. S. Bornstein ◽  
M. A. DeCrescente
Keyword(s):  
Oxide Scale ◽  
Interfacial Chemistry ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Scale Adherence ◽  
Oxide Scale Adherence

Additional Engine Testing of an Advanced Alloy for Microturbine Primary Surface Recuperators

2006 ◽  
Author(s):  
Wendy J. Matthews
Keyword(s):  
Operating Temperature ◽  
Engine Test ◽  
Test Results ◽  
Preliminary Estimate ◽  
Parabolic Model ◽  
Scale Growth ◽  
Temperature Oxide ◽  
Model Engine ◽  
Engine Testing ◽  
Elemental Depletion

HAYNES ® alloy HR-120 ® is being evaluated as a replacement for type 347 stainless steel for use in Microturbine Primary Surface Recuperators. The material has been characterized after being subjected to both steady-state and cyclic engine exposure in a Capstone C60 MicroTurbine™ operating at 100°F above the normal operating temperature. Oxide scale growth and elemental depletion has been analyzed and documented after 1,800 and 2,500 hours of exposure. A preliminary estimate of the remaining usable oxidation life has been made using a simplified parabolic model. Engine test results indicate that HR-120 has improved oxidation resistance and elemental stability.

The role of (FeCrSi)2(MoNb)-type Laves phase on the formation of Mn-rich protective oxide scale on ferritic stainless steel

2018 ◽  
Vol 132 ◽  
pp. 214-222 ◽  
Author(s):  
Harri Ali-Löytty ◽  
Markku Hannula ◽  
Timo Juuti ◽  
Yuran Niu ◽  
Alexei A. Zakharov ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Oxide Scale ◽  
Ferritic Stainless Steel ◽  
Laves Phase ◽  
Protective Oxide ◽  
Protective Oxide Scale
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