Pit-To-Crack Transition and Corrosion Fatigue of 12% Cr Steam Turbine Blade Steel
Several cases of undefined conditions during operation of steam turbines,such as shut down of the turbine or leaking of the condenser,can lead to a corrosive environment.If the concentration of oxygen and chloride exceeds a critical level,pitting corrosion can occur.Since corrosion pits increase the local stress field,the initiation of fatigue cracks is facilitated and-under adverse conditions-these cracks can lead to final failure.In this work,the results of fatigue tests on 12% Cr martensitic stainless steel,which is a standard blade material in the low pressure part of a steam turbine,are presented.The influence of corrosion pits and environment on the fatigue limit is investigated.Pit-to-crack transition is studied by optical observation and fractographic examination.The test environments were air at 90 ℃ and an aqueous solution with defined content of chloride and oxygen.To simulate an aggressive environment in which corrosion pits can form,fatigue tests in aerated 6 ppm Cl- solution at 90 ℃ are performed.
Corrosion Fatigue Pitting Corrosion Very High Cycle Fatigue Kitagawa Diagram 12 Cr Steel
Bernd M.Sch(o)nbauer Andrea Perlega Stefanie E.Stanzl-Tschegg
Institute of Physics and Material Sciences,University of Natural Resources and Life Sciences,BOKU,Peter-Jordan-Str.82,1190 Vienna,Austria
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）