Use of Alloy 800H as a Heat-Exchanger Material
Identification and characterization of structural materials for high-temperature heat exchangers to be used in nuclear hydrogen generation pose severe challenge to scientists and engineers. However, Alloy 800H has been widely used for high-temperature applications in the presence of hostile environments in view of its superior metallurgical and corrosion properties documented in the published literature (1-5). The tensile properties of Alloy 800 H have been determined at temperatures ranging from ambient to 600°C. The tensile strength of this alloy was gradually reduced with increasing temperature, as expected. However, some reduction in failure strain was noted at temperatures up to 200°C, which can be attributed to the dynamic stain ageing effect. The results of stress-corrosion-cracking (SCC) testing performed in a simulated acidic solution at constant-load (CL) did not exhibit any failure. The magnitude of true failure stress was gradually reduced in SCC testing under a slow-strain-rate (SSR) condition without showing any significant variation in ductility parameters. The localized corrosion study conducted in a similar environment by a polarization technique revealed more active (negative) critical potentials at elevated temperatures. The fractographic evaluations of the tested specimens showed dimpled microstructures indicating ductile failures.
Alloy 800H; Alloys – Cracking; Alloys – Fatigue; Alloys – Fracture; Corrosion resistance; Heat exchangers – Materials; High temperatures; Hydrogen as fuel; Nuclear energy; Tensile properties; Fractography; Stress corrosion
Materials Science and Engineering | Mechanical Engineering | Mechanics of Materials | Metallurgy | Oil, Gas, and Energy | Sustainability
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Roy, A. K.,
Use of Alloy 800H as a Heat-Exchanger Material.
2005 AIChE Annual Meeting and Fall Showcase
American Institute of Chemical Engineers.