Performance of alloy 800H for high-temperature heat exchanger applications.pdf

Materials Science and Engineering A 452–453 (2007) 665–672
Performance of alloy 800H for high-temperature
heat exchanger applications
Ajit K. Roy ∗, Vinay Virupaksha
Department of Mechanical Engineering, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway,
Box 454027, Las Vegas, NV 89154-4027, United States
Received 4 August 2006; accepted 2 November 2006
Abstract
The tensile properties of austenitic Alloy 800H have been evaluated at temperatures ranging from ambient to 1000 ◦C. The results indicate that
the tensile strength was gradually reduced with increasing temperature. Between ambient temperature and 200 ◦C, the failure strain was reduced
possibly due to the occurrence of dynamic strain aging followed by its enhancement at temperatures up to 500 ◦C. Alloy 800H did not exhibit any
failure in an acidic solution at constant-load. However, the true failure stress in this environment was reduced at elevated temperatures under a
slow-strain-rate condition. The magnitude of electrochemical potentials became more active with increasing temperature. A detrimental effect of
more noble controlled potential on the cracking susceptibility was noted in terms of the true failure stress. bination of ductile and intergranular
brittle failures was seen in the primary fracture surface of the tested cylindrical specimens.
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