Fatigue testing of miniature test specimens and correlation of the results with the standard test specimens

This paper deals with the correlation of the fatigue tests results obtained on standard and miniature test samples. The aim was to compare the fatigue properties (Wohler curves) of the samples of 15CH2NMFA steel of different cut off CT/50 test specimens after fracture toughness tests. The advantage of the use of these miniature samples is the minimum volume of removed material necessary for the production of test samples. This makes it possible to check the components in service, e.g. pressure vessels, steam turbine casings and rotors, steam pipelines, and other components of power plants after some time of operation in order that the residual lifetime could be determined. The article discusses the design of tests samples and clamping fixtures, test conditions and resulting correlation of test results.