COMPARISON OF P92 STEEL FATIGUE TEST RESULTS IN RELATION TO SPECIMEN SIZE AND MANUFACTURING

This paper describes fatigue properties of steel P92. This material is used as a standard in the energy industry, especially for production of pipes and flange branches and distance pieces of supercritical steam turbines. This material contains (unlike material P91) up to 2% of tungsten which has positive influence on creep strength increase. Compared to the P91 material, it is possible to reduce wall thickness of the P92 pipe up to 20%. Fatigue tests were carried out on standard samples and compared with SFT samples (Small Fatigue Test). SFT samples can be gently withdrawn from energy component by SSam 2 device made by company Rolls Royce. There is no necessity for shutdown of power plant. Thanks to the existing correlations between SFT and Fatigue tests, it is possible to determine mechanical properties of material from a small amount of withdrawn material. At the same time a comparison between a traditional way of sample production and a sample production by means of waterjet cutting was carried out.