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Gewählte Publikation:

Schonbauer, BM; Stanzl-Tschegg, SE; Perlega, A; Salzman, RN; Rieger, NF; Zhou, SQ; Turnbull, A; Gandy, D.
(2014): Fatigue life estimation of pitted 12% Cr steam turbine blade steel in different environments and at different stress ratios
INT J FATIGUE. 2014; 65: 33-43. FullText FullText_BOKU

The influence of corrosion pits on the endurable fatigue loading in different environments and at various stress ratios has been investigated for 12% Cr steam turbine blade steel. Very high cycle fatigue measurements were performed using ultrasonic fatigue testing technique with superimposed static load at stress ratios ranging from R = 0.05 to R = 0.9. Fatigue crack growth rate (FCGR) measurements in the near threshold regime and S-N tests were conducted at a temperature of 90 degrees C in air, de-aerated 300 ppb Cl- solution and aerated 6 ppm Cl- solution. The influence of corrosion pits on the fatigue limit was determined with artificially generated corrosion pits. It was found that the FCGRs in solution are lower and the threshold stress intensity factor ranges Delta K-th are higher than in air. Fracture surface investigation with scanning electron microscope and roughness measurement were made which suggest oxide and roughness induced crack closure as the most appropriate explanation. Data evaluation of fatigue life tests with pre-pitted specimens supports the applicability of treating pits as effective cracks. An estimation for the stress intensity factor range of pits which allows determining the endurable fatigue loading was empirically found. (C) 2013 Elsevier Ltd. All rights reserved.
Autor*innen der BOKU Wien:
Perlega Andrea
Schönbauer Bernd
Tschegg Stefanie

Find related publications in this database (Keywords)
Pitting corrosion
12% Cr steam turbine blade steel
Very high cycle fatigue
Kitagawa-Takahashi diagram
Fatigue crack growth rate

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