TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Boehm, Rainer A1 - Perez-Alonso, M. T1 - A comparison between ASTM E588 and SEP 1927 relating resolution limits at determination of the purity grade N2 - With increased usage of highly demanded, modern materials on safety relevant parts (e.g. railway wheel sets, generator shafts, turbine disks, medical implants, etc.) comprehensive analyses regarding the quality of the material are requested. This gives a focus to non-destructive methods using ultrasound immersion tank testing for classifying the degree of purity. Two autonomous standards, ASTM E588 and SEP 1927, have been established for the definition, execution and evaluation for this high resolution ultrasonic measurements on steel products. The propagation of ultrasonic waves and the resulting sound field are strongly dependent on the acoustical properties of the inspected material and the geometry of probes and specimen. The definition of the measurement setup and the evaluation methods appear to differ significantly in the given standards. ASTM E588 and SEP 1927 prescribe the requirement for surface roughness and probe selection, are using threshold based methods for cleanliness detection, but differ in computation for the degree of purity. This has been the motivation for a comparison between both standards with the main focus on amplitude depth dependency and overall spatial resolution taking the influence of different material characteristics, geometry of the specimen and sound fields into account. A performance comparison between the use of non-focusing and focusing probes respective to the threshold based detection will be presented in this contribution. In addition, the usage of complex reconstruction algorithms (e.g. SAFT, echo tomography) is compared with the traditional approaches of inclusion detection and estimation of the degree of purity T2 - 19th World Conference on Non-Destructive Testing 2016 CY - Munich, Germany DA - 13.06.2016 KW - Ultrasonic immersion tank testing KW - Purity grade KW - Material characterisation PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-382972 SP - Paper X15, 1 EP - 10 AN - OPUS4-38297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Pérez Alonso, M. A1 - Albarrán Sanz, J. A1 - Dinkel, M. A1 - Heckel, Thomas A1 - Kotschate, Daniel A1 - Cabeza, Sandra A1 - Senaneuch, J. A1 - Heikkila, I. A1 - Toscanelli, O. T1 - A novel approach for rating fatigue-initiating inclusions in highly demanding steel (INCAFAT) N2 - INCAFAT project aimed to improve existing fatigue damage models by establishing the most suitable combination of measurement techniques to characterise harmful inclusion populations in highly demanding steels. The different inclusion assessments carried out confirm that, chemical composition, secondary metallurgy and manufacturing route affect content, nature, size and shape of inclusions. According to the FEM model, inclusions produce an alteration of the stress field in their surrounding region, which can promote a fatigue failure. Experimental work on fatigue testing has demonstrated that depending on the stressed direction fatigue failures in highly demanding steels could be produced by different types of inclusions. Fractography analyses confirmed that meso-inclusions harmful in fatigue cannot be rated by standard methods, nor 10 MHz ultrasonic testing (macro) or micro-cleanness assessments. The necessity of rating these meso-inclusions has led to critical evaluation of Extreme Value Analysis according to ASTM E2283-08 and the development of high frequency immersion ultrasonic testing. EVA methodology based on inclusion width can be applied reliably when principal stress is parallel to the rolling direction. On the contrary, if inclusions are testing in the elongated directions its fails. On the other hand, the guidelines and recommendations for high frequency ultrasonic testing have been compiled in a new European standard draft. This method based on focal beam probes and high-resolution devices is able to provide information on meso-inclusion distribution. KW - Material characterisation KW - Non-destructive testing KW - Ultrasonic testing KW - Cleanliness PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-479219 UR - https://publications.europa.eu/en/publication-detail/-/publication/6bd25206-316a-11e8-b5fe-01aa75ed71a1/language-en/format-PDF/source-68610160 SN - 978-92-79-76985-6 SN - 1831-9424 SN - 1018-5593 SP - 1 EP - 154 AN - OPUS4-47921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -