TY - CONF A1 - Sonntag, Nadja A1 - Stegemann, Robert A1 - Skrotzki, Birgit A1 - Kreutzbruck, Marc ED - Grellmann, W. ED - Frenz, H. T1 - Verformungsinduzierte Magnetisierung ferromagnetischer Stähle am Beispiel eines unlegierten Baustahls T2 - Tagung Werkstoffprüfung 2014 - Fortschritte in der Werkstoffprüfung für Forschung und Praxis - Werkstoffeinsatz, Qualitätssicherung und Schadensanalyse CY - Berlin, Germany DA - 2014-12-04 KW - MMM KW - 3D-GMR-Magnetometer KW - Topografie KW - Verformungsinduzierte Magnetisierung KW - Baustahl KW - 3D-GMR magnetometer KW - Topography KW - Deformation-induced magnetization KW - Construction steel PY - 2014 SN - 978-3-9814516-8-9 SN - 1861-8154 SP - 355 EP - 360 AN - OPUS4-32222 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stegemann, Robert A1 - Sonntag, Nadja A1 - Sharatchandra Singh, W. A1 - Kreutzbruck, Marc A1 - Skrotzki, Birgit T1 - Ein Blick auf die Metal Magnetic Memory Methode nach ISO 24497 durch die Lupe hochauflösender GMR-Sensorik N2 - Die Messung spontaner magnetischer Streufelder ferromagnetischer Materialien wird als neue, Metal Magnetic Memory (MMM) genannte, Methode der zerstörungsfreien Prüfung (ZfP) angesehen, Schädigungen frühzeitig vorherzusagen. Die MMM Methode versucht, die sich gleichzeitig mit der Schadensentwicklung ausbildende lokale magnetische Struktur für die ZfP zu nutzen und zwar schon vor der eigentlichen Rissinitiierung. Das zugehörige Regelwerk ISO 24497 verspricht neben der Detektion von Mikrorissen und Inhomogenitäten des Werkstoffgefüges auch die Bestimmung des (Eigen-) Spannungszustandes. Neue, an der Bundesanstalt für Materialforschung und -prüfung für die ZfP angepasste GMR (Giant Magneto Resistance)-Sensorik erlaubt Magnetfeldmessungen mit einer Ortsauflösung im Mikrometerbereich. Mit höherer Ortsauflösung zeigen sich Unterschiede, jedoch keine Widersprüche zu bisher publizierten Daten. Ihnen wesentlich ist, dass es einige verwertbare Hinweise auf einen Zusammenhang von Restfeldmagnetisierung und Materialeigenschaften gibt. T2 - DACH-Jahrestagung 2015 CY - Salzburg, Austria DA - 11.05.2015 KW - GMR KW - Metal Magnetic Memory KW - ZfP KW - Materialwissenschaft PY - 2015 SN - 978-3-940283-68-9 IS - DGZfP BB 152 SP - Poster 1, 1 EP - 8 AN - OPUS4-33728 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stegemann, Robert A1 - Sonntag, Nadja A1 - Kreutzbruck, Marc A1 - Skrotzki, Birgit ED - Brune, M. ED - Buffière, J.Y. ED - Morel, F. ED - Nadot, Y. T1 - Self-magnetic-leakage field detection using magneto-optical sensor technique N2 - Measurement of spontaneous magnetic stray field signals has been reported to be a promising tool for capturing macro-scale information of deformation states, defects and stress concentration zones in a material structure. This paper offers a new method for self-magnetic leakage field detection using a magneto-optical (MO) hand-held microscope. Its sensor has a dynamic field range between ±0.05 and ±2 kA/m and a lateral optical resolution of approx. 10 µm. We examined flat tensile test specimens of metastable austenitic steel AISI 304. Static tensile tests were repeatedly interrupted at various predetermined states of strain and the magnetic information was measured by the MO system. Comparative measurements using a high-precision magnetic field GMR-sensor, verify the outstanding capability of the MO microscope regarding spatial resolution of magnetic fields. T2 - FDMDII-JIP 2014 - 14th International spring meeting CY - Paris, France DA - 06.11.2014 KW - Magneto-optical sensor KW - Metal magnetic memory KW - GMR KW - NDT PY - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-326911 SN - 978-2-7598-1274-5 N1 - Serientitel: Materials science, Engineering and Chemistry – Series title: Materials science, Engineering and Chemistry VL - 12 SP - 04010-1 EP - 04010-3 PB - EDP Sciences AN - OPUS4-32691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Pelkner, Matthias A1 - Lyamkin, Viktor A1 - Sonntag, Nadja A1 - Bruno, Giovanni A1 - Skrotzki, Birgit A1 - Kreutzbruck, Marc T1 - Evaluation of high spatial resolution imaging of magnetic stray fields for early damage detection N2 - The paper discusses the evaluation of elastic and plastic strain states in two low-carbon steels of the same steel group with high spatial resolution GMR (giant magneto resistance) sensors. The residual stress distributions of tungsten inert gas welded plates were determined by means of neutron diffraction as a reference. The normal component of local residual magnetic stray fields arise in the vicinity of the positions of maximum stress. The experiments performed on flat tensile specimen indicate that the boundaries of plastic deformations are a source of stray fields. The spatial variations of magnetic stray fields for both the weld and the tensile samples are in the order of the earths magnetic field. T2 - 43rd Annual Review of Progress in Quantitative Nondestructive Evaluation, Volume 36 CY - Atlanta, Georgia, USA DA - 17.07.2016 KW - Plastic deformation KW - GMR KW - Neutron diffraction KW - Residual stress KW - Microstructure KW - Low carbon steel KW - TIG weld PY - 2017 SN - 978-0-7354-1474-7 U6 - https://doi.org/10.1063/1.4974688 SN - 0094-243X VL - 1806 IS - 1 SP - Article UNSP 110010-1 EP - 10 PB - AIP Publishing CY - Melville, NY 11747 AN - OPUS4-39279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Skrotzki, Birgit A1 - Stegemann, Robert A1 - Löwe, Peter A1 - Kreutzbruck, M. T1 - The role of surface topography on deformation-induced magnetization under inhomogeneous elastic-plastic deformation N2 - It is widely accepted that the magnetic state of a ferromagnetic material may be irreversibly altered by mechanical loading due to magnetoelastic effects. A novel standardized nondestructive testing (NDT) technique uses weak magnetic stray fields, which are assumed to arise from inhomogeneous deformation, for structural health monitoring (i.e., for detection and assessment of damage). However, the mechanical and microstructural complexity of damage has hitherto only been insufficiently considered. The aim of this study is to discuss the phenomenon of inhomogeneous “self-magnetization” of a polycrystalline ferromagnetic material under inhomogeneous deformation experimentally and with stronger material-mechanical focus. To this end, notched specimens were elastically and plastically deformed. Surface magnetic states were measured by a three-axis giant magnetoresistant (GMR) sensor and were compared with strain field (digital image correlation) and optical topography measurements. It is demonstrated that the stray fields do not solely form due to magnetoelastic effects. Instead, inhomogeneous plastic deformation causes topography, which is one of the main origins for the magnetic stray field formation. Additionally, if not considered, topography may falsify the magnetic signals due to variable lift-off values. The correlation of magnetic vector components with mechanical tensors, particularly for multiaxial stress/strain states and inhomogeneous elastic-plastic deformations remains an issue. KW - Magnetic stray fields KW - Magnetomechanical effect KW - Damage KW - Topography KW - Multiaxial deformation KW - Notch KW - Plastic deformation KW - Metal magnetic memory KW - Digital image correlation KW - Structural steel PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-457878 SN - 1996-1944 VL - 11 IS - 9 SP - 1518, 1 EP - 26 PB - MDPI CY - Basel, Switzerland AN - OPUS4-45787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -