TY - CONF A1 - Quiroz Penaranda, Vanessa A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Investigations on laser beam welding of high-manganese austenitic and austenitic-ferritic stainless steels N2 - Influence of the main laser welding parameters on process stability and resulting weld quality were investigated. Effects of weld edge preparation on the weld appearance and quality were considered. The obtained welded joints were subjected to radiographic tests for detection of internal imperfections. Metallurgical characterisation of the samples regarding the resulting phase composition and hardness was conducted. Tensile and potentiodynamic tests were performed to evaluate the mechanical and corrosion properties. The results provide an insight into the advantages and limitations of the laser welding process for joining high-manganese alloyed stainless steels. Conditions for the production of defect-free and corrosion-resistant welds having good mechanical properties could be determined. T2 - LTWMP '11 - 5th International conference "Laser technologies in welding and materials processing" CY - Crimea, Ukraine DA - 24.05.2011 PY - 2011 SP - 55 EP - 59 AN - OPUS4-25475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Deresch, Andreas A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Przybilla, Waldemar ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Measurement and modeling of scatter ratios at high energies N2 - Determining scatter ratios at high energies (> ~ 1MeV) presents challenges not immediately obvious from measurements at conventional X-ray energies. This includes reduced attenuation even in heavy elements as well as a stronger forward bias of scattering. In order to check the reliability of different measurement setups with regard to material thicknesses, distances, and collimation, attenuation and scattering were separately simulated using a Monte Carlo model. The simulation results help in understanding the sources of radiation scattered into the detection area, thereby aiding in eliminating undesired contributions. T2 - 37th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - San Diego, CA, USA DA - 18.07.2010 KW - Radiography KW - Optimisation KW - X-ray detection KW - Simulation KW - High energy KW - Co-60 KW - Modeling KW - Scatter PY - 2011 SN - 978-0-7354-0888-3 DO - https://doi.org/10.1063/1.3591895 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1335 SP - 517 EP - 524 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-25358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böllinghaus, Thomas A1 - Mente, Tobias T1 - Vermeidung von Rissen beim Schweissen von Rohrleitungen N2 - Schadensfälle in den letzten zehn Jahren mit teilweise katastrophalen Folgen belegen, dass der Vermeidung von Rissen beim Schweißen von Rohrleitungen besondere Aufmerksamkeit zu schenken ist. In der Analyse solcher Schäden ist zu unterscheiden, ob die Risse bereits während oder kurz nach der schweißtechnischen Fertigung der Rohrkomponenten oder während des anschließenden Betriebes entstanden sind. Im vorliegenden Beitrag wird sich vor allem auf die Vermeidung einer Heiß- und Kaltrissbildung beim Schweißen von Rohrleitungen konzentriert und es werden weitere Forschungsperspektiven abgeleitet. T2 - DVM-Tag 2011 - Bauteilzuverlässigkeit - Schäden und ihre Vermeidung CY - Berlin, Germany DA - 04.05.2011 KW - Rissvermeidung KW - Heißrissbildung KW - Wasserstoffunterstützte Kaltrissbildung (HACC) KW - Pipelineschweißungen PY - 2011 SN - 0946-5987 N1 - Serientitel: DVM-Bericht – Series title: DVM-Bericht IS - 678 SP - 81 EP - 90 AN - OPUS4-26113 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böllinghaus, Thomas A1 - Mente, Tobias A1 - Dabah, Eitan ED - Kulkarni, D.V. ED - Samant, M. ED - Krishnan, S. ED - De, A. ED - Krishnan, J. ED - Patel, H. ED - Bhaduri, A.K. T1 - Trends in investigating hydrogen cracking and diffusion in steel welds N2 - The present contribution highlights recent trends in investigating hydrogen diffusion and cracking in steel welds. For such studies, supermartensitic stainless steels (SMSS) have exemplarily been selected. These materials have been used for offshore and marine constructions for about two decades now. They present a versatility of improved properties such as high strength to thickness ratio, good weldability and good corrosion resistance. However, as shown by respective failure cases, SMSS welds might become prone to hydrogen assisted cracking and the degradation phenomena are more easily to investigate due to the nearly homogeneous martensitic microstructure than in other materials. Generally, it has to be distinguished between cracking that occurs during or shortly after fabrication welding, or during subsequent operation of SMSS components. In order to achieve crack avoidance during fabrication and service, conclusive test sequences have to be applied, ranging from field tests at real components and full scale tests investigating the materials behavior under real service conditions to basic and small scale tests, such as tensile and corrosion tests, oriented more towards a materials ranking. Considerable testing of SMSS welds has been carried out and the present paper particularly summarizes spotlights on 1:1 scale component testing of welded tubulars, slow strain rate testing and basic tests oriented to elucidate the hydrogen behavior and degradation in SMSS weld microstructures. Also, permeation tests, hydrogen dependent degradation of mechanical properties and thermal desorption spectroscopy are adressed. As a specific item, first results of lately conducted investigations for tracking hydrogen movement in such weld microstructures by using high energy synchrotron radiation are elucidated. T2 - IIW International conference on global trends in joining, cutting and surfacing technology CY - Chennai, India DA - 21.07.2011 PY - 2011 SN - 978-81-8487-152-4 SP - 49 EP - 55 PB - Narosa Publ. House AN - OPUS4-26114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - von Chrzanowski, Lars A1 - Fratzscher, Daniel A1 - Ewert, Uwe ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Spectral and spatial nondestructive examination of dielectric materials with THz time domain spectroscopy N2 - A time domain spectrometer T-ray 2000® operating in the range of 0.2-2 THz was used for Time of Flight measurements. A series of ethanol water mixtures from 10% to 90% were produced subsequently filled in polystyrene cells and analyzed in the T-ray 2000 TDS system in the reflection mode. The reflectivity of the material liquid interface is strongly influenced by the ethanol concentration in water. The reciprocal reflection coefficient of the material liquid interface was found to be a useful discriminating feature for further Probably of Detection calculations which can be used for the performance evaluation of potential THz bottle scanners. THz pulse echo (PE) measurements were performed in comparison to the established ultra sound PE technique for flaw detection of plastics. Synthetic aperture reconstructions were applied for simulated data to reconstruct the flaw shape. The results were compared with B-scan images of a high density polyethylene (HDPE) test cylinder. Existing restrictions on the quality of the back projected images and limits of the existing model are discussed in detail. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 17.07.2011 KW - Terahertz time domain spectroscopy KW - Time of flight diffraction KW - Non destructive testing KW - Polymers KW - Probability of detection KW - Thz Tomography PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716279 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 31A IS - 1430 SP - 573 EP - 580 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Weise, Matthias A1 - Bovtun, Viktor Petrovic A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Parameter reproducibility of polypropylene ferroelectret transducers for air-coupled ultrasonic testing N2 - The extremely low acoustic impedance of polypropylene ferroelectret combined with its piezoelectric properties makes this material suitable for construction of aircoupled ultrasonic transducers for non-destructive testing. For the fabrication of transducers with a stable quality, the reproducibility of their key parameters is of interest. The reproducibility was evaluated by means of (i) impedance spectroscopy and (ii) pulse-echo measurements. (i) Impedance spectroscopy was applied to identify the resonance frequency, the coupling factor and the acoustic impedance of several nominally identical transducers. (ii) Pulse-echo measurements yielded the signal form of these transducers. The variation of the signal amplitude measured with pulseecho technique was about 10 dB. A part of this variation Comes from the deposition of transducer electrodes and another part from local variations of ferroelectret properties. The variation of the signal amplitude was caused by the observed variation of the coupling factor, which was also about 10 dB. The variation of the acoustic impedance was only about 1 dB, thus having no effect on the variation of the signal amplitude. These results indicate that the variability can be reduced by improving the control of electrode deposition and by optimizing the production technology affecting the reproducibility of material properties. T2 - 2011 IEEE International ultrasonics symposium (IUS) CY - Orlando, FL, USA DA - 18.10.2011 KW - Air-coupled ultrasonic transducers KW - Polypropylene ferroelectret KW - Reproducibility PY - 2011 IS - Abstract-ID 258 SP - 1 EP - 3 AN - OPUS4-26405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marotzke, Christian T1 - Failure criterion based on adhesion for composites under transverse loading N2 - The failure of laminates usually is initiated by the failure of the plies with the maximum transverse stresses. The failure of those plies generally reduces the load carrying capability of the laminate, even though they carry only a small part of the external load. The analysis of failure under off-axis stresses accordingly is essential for the prediction of the strength of laminates. This is taken into account in the "mechanisms based failure criteria" e.g. by Puck. Most of these inter fiber failure criteria are not based on the micromechanics of the failure process but on prescribed stress interaction functions. The failure of plies under transverse loading obviously is governed by the bond strength between fiber and matrix fiber. The interfacial debonding was studied e.g. by Paris et al. and Corea et al.. The bond strength between fiber and matrix usually is measured by using micromechanical tests e.g. pull-out, push-out or fragmentation tests. Stress analyses as well as fracture mechanical analyses show that the interfacial failure over a large range is dominated by shear stresses (Kim and Mai, Pisanova et al, Marotzke and Qiao). The stress distribution arising in those experiments however differs from the stresses acting in a lamina under transverse loading. In transverse failure of a lamina, radial stresses as well as shear stresses are dominating the failure process of the interface. In addition longitudinal shear stresses are present. Experimental work concerning off-axis loading of single fibers was done e.g. by Tandon and Kim and by Ogihara and Koyanagi. They studied the influence of the fiber alignment by using a specimen in form of a cruciform with skew wings. T2 - Thermosets 2011 - From monomers to components - 2nd international conference on thermosets CY - Berlin, Germany DA - 21.09.2011 KW - Composites KW - Strength KW - Adhesion KW - Fracture mechanics PY - 2011 SN - 978-3-8396-0312-3 SP - 86 EP - 88 PB - Fraunhofer Verlag CY - Berlin AN - OPUS4-26451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Gollwitzer, Christian A1 - Jaenisch, Gerd-Rüdiger T1 - Radiographic simulator aRTist: version 2 N2 - Computer simulation of radiography can be used for different purposes in NDT, such as qualification of NDT systems, optimization of radiographic parameters, feasibility analysis, model-based data interpretation, and training of NDT/NDE personnel. BAM has been working on modeling in the field of radiographic testing for many years. With the gathered theoretical background and the familiarity with practical requirements of industrial application the simulation software aRTist has been developed. This analytical simulator includes a description of the radiation source, the interaction of radiation with test pieces and flaws, and the detection process with special focus on film and digital industrial radiology. It features high processing speed with nearinteractive frame rates and a high level of realism. Here we focus on the recent developments of the simulator, notably the release of aRTist version 2. Extended functionality regarding automated virtual computed tomography now allows for arbitrary scan paths. Another program extension supports reliability investigations and provides a user interface for planning automatic simulations with varying parameters and defects. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 16.04.2012 KW - X-ray imaging KW - Radiographic testing KW - Simulation KW - Computed tomography PY - 2012 SN - 978-0-620-52872-6 SP - 1 EP - 7 (Paper 333) AN - OPUS4-27398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Oliver A1 - Adam, Christian T1 - Sewage sludge ashes - composition, mass flows, and recovery potential N2 - Sewage sludge ashes (SSA) represent a possible source of phosphorus (P) and technology metals. So far, the sole external source for P, that is indispensable for all animate beings, is rock phosphate, a finite resource. The EU depends completely on the import from possible politically instable regions. Furthermore, rock phosphate is often contaminated with heavy metals like Cd and U, leading to health and environmental hazards. P recovered from SSA might diminish these problems. SSA of German mono incineration facilities are analyzed for their elemental composition. More than 95% of the emerging SSA is monitored, enabling the determination of complete mass flows of the ashes and their components. Initial results indicate a P recovery potential of 16,000 t/a (11% of the annual P demands for fertilizer production). The concentrations of Cd and U in SSA are one to two Orders of magnitude lower than in rock phosphate and could help to reduce possible hazards. T2 - 14th International waste management and landfill symposium - Sardinia 2013 CY - Cagliari, Italy DA - 30.09.2013 PY - 2013 SP - 1 EP - 5 PB - CISA Publisher AN - OPUS4-29734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kühn, Hans-Joachim ED - Christ, H.-J. T1 - Vom E-Modul bis zum TMF-Versuch - Praktische Herausforderungen der Werkstoffprüfung N2 - Durch Normen werden die für die Kennwertbestimmung erforderlichen Versuchsbedingungen (z. B. Belastungsgeschwindigkeit, Klasse der Prüfmittel) und auch die Datenauswertung eindeutig festgelegt. Sie sind die Grundlage für eine belastbare Kennwertermittlung und dürfen bei normkonformen Versuchen nicht ignoriert werden. Weiterführende Betrachtungen (Plausibilität, cross-check) finden sich dagegen in Normen sehr selten. Hier eröffnet sich nun dem Werkstoffprüfer ein weites Feld. Zum einen können die Versuchsabläufe unter Berücksichtigung des im Labor vorhandenen Inventars optimiert, zum anderen können durch erweiterte Auswertung der Messdaten Hinweise auf eine fehlerhafte Versuchsführung gefunden werden. Werden dagegen von der Norm abweichende oder nicht genormte Versuche durchgeführt, sind der Kreativität des Werkstoffprüfers kaum Grenzen gesetzt. Dieses wird durch die schnell fortschreitende Entwicklung auf dem Gebiet der Mess- und Prüftechnik unterstützt. An Beispielen aus meiner 36-jährigen BAM-Tätigkeit im Bereich der Werkstoffprüfung werden Prüfmittel und Lösungswege zu unterschiedlichen Aufgabenstellungen vorgestellt. Die gewählten Beispiele stehen auch für die Werkstoffprüfung im Wandel der Zeit und belegen die gewachsenen Anforderungen an den Werkstoffprüfer N2 - Standards clearly define the test conditions (e.g. loading rate, class of test equipment) and data analysis for the determination of the test results. They are the basis for a reliable determination of parameters and must not be ignored in standard-compliant tests. However, additional considerations (plausibility, cross-check) are very rarely addressed in standards. This opens a wide field for the material tester. On the one hand the experimental procedures can be optimized taking into account the existing inventory in the laboratory; on the other hand a faulty experimental procedure can be identified by advanced analysis of the measured data. If non-standard-tests are performed there are hardly any creative limits for the material tester. This is supported by the rapid increase of development in the field of measuring and testing technique. Using examples from my 36-year BAM activity in the field of material testing, equipment and solutions are presented for different tasks. The examples also show material testing in the course of time and confirm the growing demands on the material tester. T2 - Tagung Werkstoffprüfung 2013 - Fortschritte in der Werkstoffprüfung für Forschung und Praxis CY - Neu-Ulm, Germany DA - 28.11.2013 KW - Elastizitätsmodul KW - Zugversuch KW - Temperaturmessung KW - TMF-Versuch KW - Modulus of elasticity KW - Tensile test KW - Temperature measurement KW - TMF-test PY - 2013 SN - 978-3-514-00806-9 SP - 49 EP - 58 PB - Verlag Stahleisen AN - OPUS4-29736 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -