Zur Schwingungsrisskorrosion hochfester austenitischer Stähle

Translated title of the contribution: Corrosion fatigue of high strength austenitic steels

Robert Sonnleitner

Research output: ThesisDoctoral Thesis


Material damage and failure of austenitic stainless steels because of corrosion fatigue is a frequently appearing damage. On the one hand, metallic alloys loose their fatigue resistance under corrosive conditions and on the other hand, the ambient conditions are often not recognized as corrosive. In addition, characterisation of failures is commonly not easy because it is difficult to distinguish a corrosion fatigue fracture and a conventional fatigue fracture. In this work, the fundamental corrosion fatigue mechanisms of two austenitic stainless steels with different alloying concepts were investigated. At the beginning, testing equipment was built up and put into operation. Testing methods for testing under hot, high aggressive conditions were developed. At the end of this thesis, testing methods and a strong data base were available for further work. The tested materials were a superaustenitic CrNiMoN alloyed steel and an austenitic CrMnN alloyed steel. These materials were industrially manufactured with similar parameters in three different degrees of cold work. Among others, these steels are used in the oil industry during deep boreholes as drill collars. At this application, they are dynamically loaded in hot, high chloride containing media. At this work, the same testing parameters (frequency, chloride concentration and temperature) were chosen as they appear in practice. Stress versus number of cycles curves were recorded with servohydraulic universal testing machines in inert glycerin and corrosive 43 Wt% CaCl2 solution at 120°C and 20 Hz. Furthermore, crack propagation curves were recorded in the array of linear fracture mechanics with the direct current potential drop method under same conditions as the stress versus number of cycles curves. To get a full picture of the two austenitic stainless steels, additional made electrochemical tests, exposure tests, constant load tests as well as atomic force microscopic investigations were done. The characterisation of the fracture appearance was made with conventional and high resolution scanning electron microscopy.
Translated title of the contributionCorrosion fatigue of high strength austenitic steels
Original languageGerman
  • Clemens, Helmut, Assessor B (internal)
  • Mori, Gregor Karl, Assessor A (internal)
Publication statusPublished - 2009

Bibliographical note

no embargo


  • Corrosion fatigue
  • austenitic stainless steels
  • stress versus number of cycles curves
  • crack propagation rate curves

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