Evaluation of candidate Stirling engine heater tube alloys after 3500 hours exposure to high pressure doped hydrogen or helium. Final report
Sixteen commercial tubing alloys were endurance tested at 820/sup 0/ C, 15 MPa in a diesel-fuel fired Stirling engine simulator materials test rig: iron-base N-155, A-286, Incoloy 800, 19-9DL, CG-27, W-545, 12RN72, 253MA, Sanicro 31H and Sanicro 32; nickel-base Inconel 601, Inconel 625, Inconel 718, Inconel 750 and Pyromet 901; and cobalt-base HS-188. The iron-nickel alloys CG-27 and Pyromet 901 exhibited superior oxidation/corrosion resistance to the diesel-fuel combustion products and surpassed the design criterias' 3500 h creep-rupture endurance life. Three other alloys, Inconel 625, W-545, and 12RN72, had creep-rupture failures after 2856, 2777, and 1598 h, respectively. Hydrogen permeability coefficients determined after 250 h of rig exposure show that Pyromet 901 had the lowest Phi value, 0.064x10/sup -6/ cm/sup 2//s MPa/sup 1///sup 2/. The next five hairpin tubes, CG-27, Inconel 601, Inconel 718(wd), Inconel 750, and 12RN72(cw) all had Phi values below 0.2x10/sup -6/ more than a decade lower than the design criteria. Based upon its measured high strength and low hydrogen permeation, CG-27 was selected for 3500 h endurance testing at 21 MPa gas pressure and 820/sup 0/C. Results of the high pressure, 21 MPa, CG-27 endurance test demonstrated that the 1.0 vol % C0/sub 2/ dopant is an effective deterrent to hydrogen permeation. The 21 MPa hydrogen gas pressure apparent permeability coefficient at 820/sup 0/C approached 0.1x10/sup -6/ cm/sup 2/sec MPa/sup 1///sup 2/ after 500 hr, the same as the 15 MPa test. Even at this higher gas pressure and comparable permeation rate, CG-27 passed the 3500 hr endurance test without creep-rupture failures. It is concluded that the CG-27 alloy, in the form of thin wall tubing is suitable for Stirling engine applications at 820/sup 0/C and gas pressures up to 21 MPa.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- DOE Contract Number:
- AI01-77CS51040
- OSTI ID:
- 6423348
- Report Number(s):
- DOE/NASA/51040-56; NASA-TM-83782; ON: DE85001433
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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36 MATERIALS SCIENCE
ALLOY-A-286
PERFORMANCE TESTING
ALLOY-N-155
HEAT RESISTING ALLOYS
INCOLOY 800
INCONEL 625
INCONEL 718
INCONEL ALLOYS
STIRLING ENGINES
MATERIALS TESTING
CARBON DIOXIDE
COMBUSTION PRODUCTS
DIESEL FUELS
HELIUM
HYDROGEN
PERMEABILITY
TENSILE PROPERTIES
VERY HIGH TEMPERATURE
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
CARBON ADDITIONS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHROMIUM ALLOYS
COBALT ALLOYS
ELEMENTS
ENGINES
FLUIDS
GASES
HEAT ENGINES
HEAT RESISTANT MATERIALS
INCOLOY ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ADDITIONS
NIOBIUM ALLOYS
NITROGEN ADDITIONS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
RARE GASES
SILICON ADDITIONS
SILICON ALLOYS
TANTALUM ADDITIONS
TANTALUM ALLOYS
TESTING
TITANIUM ALLOYS
TUNGSTEN ALLOYS
330201* - External Combustion Engines- Stirling Cycle
360105 - Metals & Alloys- Corrosion & Erosion