Creep-fatigue prediction of low alloy ferritic steels using a strain energy based methodology
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Date
2009-07-26
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American Society of Mechanical Engineers (ASME)
Abstract
The accumulation of creep-fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model that calculates the creep damage under conditions of strain control has been developed that assumes on a macroscopic level that the energy dissipated in the material may be taken as a measure of the creep damage induced in the material. This then assumes that the creep damage is directly proportional to absorbed internal energy density. The model developed is derived from considerations of mechanistic cavity growth. The model makes use of already existing creep data and relatively easily determined fatigue data for estimation of life under non-steady state conditions. The predictions of the energy-density exhaustion approach are compared with the results of creep-fatigue tests on a low alloy ferritic steel 1/2Cr-1/2Mo-1/4V (CMV) and with creep-fatigue calculations using a number of current models. The predicted results of the energy-density model are found to have good correlation with the measured creep-fatigue lives.
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Keywords
Creep, Fatigue, Ferritic steels, Strains, Damage, Energy density
Citation
Payten, W. M., Dean, D. W., & Snowden, K. U. (2009). Creep-fatigue prediction of low alloy ferritic steels using a strain energy based methodology. ASME 2009 Pressure Vessels and Piping Conference (PVP2009), 26th – 30th July 2009. Prague, Czech Republic: Hilton Prague. In Proceedings of the ASME Pressure Vessels and Piping Conference 2009 - Materials and Fabrication, Parts A and B, 6, (pp. 1403-1410). doi:10.1115/PVP2009-77208