TY - CONF A1 - Bismarck, Marck A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Size effects in miniature specimen creep testing of P91 T2 - ECCC 2014 N2 - The use of miniaturized specimen geometries in mechanical testing allows extracting the sample material directly from critical components of power plants like e.g. headers and pipes. In this way, both the impacts of the manufacture of the component (including all shaping and tempering influences) and of the complex aging/loading/oxidation conditions during Service can be analyzed and representative mechanical properties are obtained. In the present study, example results of a comparative creep and creep rupture study on P91 tempered martensite ferritic Steel, involving Standard and miniature specimens that were all taken from one batch of material, are presented. Cylindrical creep specimens with a minimum gauge length diameter of 3 mm were used, representing the smallest recommended test geometry of ISO 204. The test results of miniature specimens exhibit all characteristic creep features of tempered martensite ferritic steels, and analysis of the stress and temperature dependence of creep results in values that correspond well to literature data for P91. However, direct comparison with large scale specimen data reveals small but systematic variations in minimum creep rates, elongations at fracture and times to rupture. In our contribution, these differences are discussed in the light of literature findings on specimen size influences in other heat resistant alloys. Size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. PB - Tipography Inail CY - Milan T2 - 3rd International ECCC Conference CY - Rom, Italy DA - 05.05.2014 KW - Material PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/41239 AN - OPUS4-41239 SN - 978-88-7484-510-1 SP - 430 EP - 435 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany