TY - JOUR A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - Carbon capture and storage PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391 DO - https://doi.org/10.3390/pr9040594 SN - 2227-9717 VL - 9 IS - 4 SP - 1 EP - 33 PB - MDPI CY - Basel AN - OPUS4-53139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Kranzmann, Axel T1 - Effects of saline aquifer water on the corrosion behaviour of martensitic stainless steels during exposure to CO2 environment N2 - Immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 and X5CrNiCuNb16-4 at T=60 °C and ambient pressure and p=100 bar were performed for 700 h - 8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS-sites in the Northern-German-Basin. Main corrosion products are FeCO₃ and FeOOH. Highest surface corrosion rates at ambient pressure are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4. Corrosion rates at 100 bar (max. 0.01 mm/year for 42CrMo4, X20Cr13, X46Cr13) are generally lower than at ambient pressure (<0.01 mm/year for X35CrMo4, X5CrNiCuNb16-4). Heat treatment to martensitic microstructure offers good corrosion resistance. T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15 CY - Abu Dhabi, United Arab Emirates DA - 15.03.2021 KW - CCS KW - Corrosion KW - High alloyed steels PY - 2021 DO - https://doi.org/10.2139/ssrn.3812248 SP - 1 EP - 12 PB - SSRN CY - Rochester, NY AN - OPUS4-53140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Evaluating corrosion and corrosion fatigue behavior via laboratory testing techniques in highly corrosive CCS-environment N2 - In CCS environment (carbon capture and storage) pipes are loaded statically and/or cyclically and at the same time exposed constantly to the highly corrosive hot thermal water. Experimental procedures such as ambient pressure immersions tests, in-situ corrosion fatigue experiments using a flexibly designed corrosion chamber at ambient pressure and a specially designed corrosion chamber at high pressure. Experimental set-ups for push/pull and rotation bending load are introduced. The corrosion behavior and lifetime reduction of high alloyed steels (X46Cr13, 1.4043), (X5CrNiCuNb16-4, 1.4542) and (X2CrNiMoN22-5-3, 1.4462) is demonstrated (T=60 °C, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO₂). T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15 CY - Abu Dhabi, United Arab Emirates DA - 15.03.2021 KW - Steel KW - Supercritical CO2 KW - Pipeline KW - Corrosion KW - CO2-storage PY - 2021 DO - https://doi.org/10.2139/ssrn.3812193 SP - 1 EP - 11 PB - SSRN CY - Rochester, NY AN - OPUS4-53142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja T1 - How flipped classroom teaching methods in first year studying succeed N2 - Flipping the classroom is a method to let students study on their own and then take time to discuss their questions and do extended hands-on lectures or exercises in class – or in the case of the covid-19 pandemic during plenary online sessions. First year mechanical engineering students use different teaching materials (mainly lecture videos, lightboard videos and micromodule lectures) to study from a distance and comprehend the principle underlying science in theory. Then the online plenary lectures offer the opportunity to apply their knowledge and transfer different scientific aspects of the course to get the bigger picture. Exercises, worked solutions, selfassessed tests and peer-instruction during present time help students to check on their learning progress. However, the self-study periods and (online) plenary sessions need to be guided carefully. To meet the course learning outcome and overcome the diversity of a first year class various practical leads have to be fulfilled to turn flipped classroom teaching into success. T2 - 7th International Conference on Higher Education Advances (HEAd’21) CY - Valencia, Spain DA - 20.06.2021 KW - Inverted classroom KW - Flipped classroom KW - Online teaching KW - Lecture videos KW - First year students PY - 2021 DO - https://doi.org/10.4995/HEAd21.2021.12792 SP - 1211 EP - 1219 AN - OPUS4-54156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, M. A1 - Kranzmann, Axel T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion fatigue KW - Cabon capture and storage KW - CCS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541626 DO - https://doi.org/10.3390/pr9040594 VL - 9 IS - 4 SP - 594 PB - MDPI AN - OPUS4-54162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lemiasheuski, Anton A1 - Kranzmann, Axel A1 - Pfennig, Anja T1 - Herausforderungen und Möglichkeiten des manuellen metallografischen Serienschnittverfahrens anhand einer quantitativen Gefügeanalyse der Grafite eines Gusseisens T1 - Challenges and possibilities of the manual metallographic serial sectioning process using the example of a quantitative microstructural analysis of graphite in cast iron N2 - Die in dieser Studie vorgestellte 3D-Gefüge-Analyse konzentriert sich auf die Kugelgrafite eines Gusseisens des Typs EN-GJS. Es werden die Form anhand des Formfaktors und des Seitenverhältnisses sowie die durchschnittliche Teilchengröße und -verteilung untersucht. Die Form der Grafite in Gusseisenwerkstoffen ist mitentscheidend für die mechanischen Eigenschaften dieser Legierungen und ist bei der Charakterisierung des Werkstoffs unumgänglich. Mittels Metallografischen Serienschnittverfahrens wird von dem Schicht für Schicht abgetragenen und lichtmikroskopisch schichtweise dargestellten Werkstoff ein digitaler Zwilling erstellt. Von diesem dreidimensionalen Zwilling lassen sich beliebige Ebenen digital projizieren und analysieren. Eine konventionelle quantitative 3D-Analyse untersucht die Voxelmenge und -zusammensetzung eines Körpers im 3D-Raum. Die hier vorgestellte Analyse wendet stereologische 2D-Analyseverfahren auf drei Raumebenen des Werkstoffs an. Dabei sind zwei der Ebenen digitale Projektionen des Zwillings. Die zwei rekonstruierten Ebenen des Werkstoffs sind so gewählt, dass die Richtungsvektoren aller drei Ebenen einen 90°-Winkel zueinander bilden. Diese Methodik wird eingehend beschrieben sowie Herausforderungen und Möglichkeiten des hier vorgestellten Serienschnittverfahrens diskutiert. N2 - The 3D microstructure analysis presented in this study focuses on the nodular graphite of an EN-GJS grade cast iron. The shape is analyzed based on shape factor and aspect ratio as well as average particle size and distribution. The shape of graphites in cast iron materials is critical to the mechanical properties of these alloys and is essential for the characterization of the material. Metallographic serial sectioning creates a digital twin of the material, which is removed layer by layer and visualized layer by layer under an optical microscope. From this three-dimensional twin, any number of planes can be digitally projected and analyzed. Conventional quantitative 3D analysis examines the voxel count and composition of a body in 3D space. The analysis presented here applies stereological 2D analysis methods to three spatial planes of the material. Two of the planes are digital projections of the twin. The two reconstructed planes of the material are chosen so that the direction vectors of all three planes form an angle of 90° to each other. The methodology is described in detail and the challenges and opportunities of the serial section method presented here are discussed. KW - Dreidimensionale Gefügeanalyse KW - Three-dimensional microstructure analysis KW - 3D-Metallografie KW - Serienschnittverfahren KW - Gefügerekonstruktion KW - Quantitative Gefügeanalyse KW - 3D metallography KW - Serial sectioning KW - Microstructure reconstruction KW - Quantitative microstructure analysis PY - 2024 DO - https://doi.org/10.1515/pm-2024-0066 SN - 0032-678X VL - 61 IS - 9-10 SP - 746 EP - 768 PB - De Gruyter CY - Berlin/Boston AN - OPUS4-60976 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Mohring, Wencke A1 - Wolf, Marcus T1 - The insignificant improvement of corrosion and corrosion fatigue behavior in geothermal environment applying Boehmit coatings on high alloyed steels N2 - The efficacy of alumina-sol based coatings in a water-free atmosphere at high temperatures suggests a potential solution for enhancing the corrosion resistance of high-alloyed steels in Carbon Capture and Storage (CCS) environments. In this study, coupons of X20Cr13, designed for use as injection pipes with 13% Chromium and 0.20% Carbon (1.4021, AISI 420), were sol-gel coated with water and ethanol-based alumina. These coated coupons were then exposed to CO2-saturated saline aquifer water, simulating conditions in the Northern German Basin, for 1000 h at ambient pressure and 60 °C. Corrosion fatigue experiments were also conducted using specimens of X5CrNiMoCuNb16-4 (1.4542, AISI 630), a suitable candidate for geothermal applications, to assess the impact of the ethanol-based coating on the number of cycles to failure at different stress amplitudes. Unfortunately, the coating exhibited early spallation, resulting in corrosion kinetics and corrosion fatigue data identical to those of uncoated specimens. Consequently, the initially promising Boehmit coating is deemed unsuitable for CCS applications and further research therefore not advisable. KW - Alumina coating KW - High alloyed steel KW - Pitting KW - Surface corrosion KW - CO2 KW - Pipeline KW - Corrosion KW - CCS KW - CO2-storage PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623786 DO - https://doi.org/10.3390/app14041575 SN - 2076-3417 VL - 14 IS - 4 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-62378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, M. A1 - Kranzmann, Axel T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60°C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60°C , brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Carbon capture and storage KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - CCS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523948 DO - https://doi.org/10.3390/pr9040594 VL - 9 IS - 4 SP - 594 PB - MDPI CY - Basel, Switzerland AN - OPUS4-52394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lemiasheuski, Anton A1 - Wehrkamp, F. A1 - Bajer, Evgenia A1 - Sonnenburg, Elke A1 - Göbel, Artur A1 - Porohovoj, Ilja A1 - Bettge, Dirk A1 - Pfennig, Anja T1 - Practical application of an automated 3D metallography system for the reconstruction and microstructural analysis of porosity in a sintered steel N2 - In the 3D microstructural analysis of a digital twin of porosity in the sintered steel Astaloy CrA, pore shape, average pore size as well as pore distribution will be analyzed. Porosity plays a major role in powder-metallurgical materials since it greatly impacts the mechanical properties of these materials and therefore represents a key parameter in their characterization. Based on the robot-assisted automated serial sectioning and imaging (RASI) system of the Federal Institute for Materials Research and Testing (BAM, Bundesanstalt für Materialforschung und Prüfung) in Berlin, the technique of metallographic serial sectioning will be used to image the microstructure and reconstruct a digital 3D twin from the stack of images obtained. Compared with an individual 2D microsection, the quantitative microstructural analysis of this 3D twin will enable more accurate conclusions on the shape, size and distribution of pores. This paper will detail the key steps in 3D microstructural analysis, including the metallographic preparation routine, the imaging technique, image alignment as well as the segmentation of pores. After the methodology has been described, the results of the quantitative microstructural analysis will be presented and the validity of quantitative parameters of 3D and 2D images will be compared and discussed. The analysis of more than 10,000 pores revealed a correlation between pore shape and pore size. It was also found that a 2D representation of the material surface is insufficient for a precise quantitative characterization of porosity. N2 - In der 3D-Gefügeanalyse eines digitalen Zwillings von Poren in einem Sinterstahl des Typs Astaloy CrA werden sowohl die Porenform als auch die durchschnittliche Porengröße und -verteilung analysiert. Die Porosität spielt in pulvermetallurgischen Werkstoffen eine große Rolle, da sie erheblich die mechanischen Eigenschaften beeinflusst und daher bei der Charakterisierung dieser Werkstoffe ein wichtiger Parameter ist. Basierend auf der Verwendung des Robot-Assisted Automated Serial-Sectioning and Imaging (RASI)-Systems der Bundesanstalt für Materialforschung und Prüfung (BAM) in Berlin, wird das metallographische Serienschnittverfahren genutzt, um das Gefüge aufzunehmen und aus dem Bildstapel einen digitalen 3D-Zwilling zu rekonstruieren. Verglichen zu einem 2D-Einzelschliff ermöglicht die quantitative Gefügeanalyse dieses 3D-Zwillings präzisere Aussagen zu Porenform, -größe und -verteilung. Diese Arbeit beschreibt die wesentlichen Schritte, die für eine 3D-Gefügeanalyse nötig sind, darunter die metallografische Präparationsroutine, das Bildgebungs-Verfahren, das Alignment der Bilder sowie die Segmentierung der Poren. Im Anschluss an die methodische Darstellung werden die Ergebnisse der quantitativen Gefügeanalyse präsentiert und ein Vergleich zwischen der Aussagekraft der quantitativen Parameter von 3D- und 2D-Abbildungen diskutiert. Bei der Analyse von über 10.000 Poren konnte eine Korrelation zwischen der Form und der Porengröße aufgezeigt werden. Weiterhin konnte aufgezeigt werden, dass eine 2D-Abbildung der Werkstoffoberfläche nicht ausreichend für eine eindeutige quantitative Beschreibung der Porosität ist. KW - 3D Metallographie KW - RASI KW - Porenstruktur PY - 2025 DO - https://doi.org/10.1515/pm-2025-0049 SN - 2195-8599 VL - 62 IS - 8 SP - 516 EP - 535 PB - De Gruyter Brill AN - OPUS4-63930 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moschetti, Michael A1 - Lemiasheuski, Anton A1 - Bajer, Evgenia A1 - Porohovoj, Ilja A1 - Göbel, Artur A1 - Pfennig, Anja A1 - Bettge, Dirk A1 - Maaß, Robert T1 - Robot-Assisted Automated Serial-Sectioning and Imaging for 3D Microstructural Investigations N2 - Comprehensive materials characterization requires precise structural knowledge beyond traditional methods. The robot-assisted automated serial-sectioning and imaging (RASI) platform, developed at BAM, provides automated 3D metallographic reconstructions, enabling detailed microstructural analysis of technical materials. This article showcases RASI’s capabilities through several case studies, including characterization of lamellar graphite in gray cast iron, porosity in sintered steel, melt pool morphology in additively manufactured 316L stainless steel, defects in metal-ceramic packages, and oxidation behavior in an Fe-12Cr-2Co alloy. By automating sample handling, mechanical serial-sectioning, etching, and optical imaging, RASI captures complex 3D microstructures with high precision and at high speed. This approach reveals microstructural features missed by 2D analysis, even using stereological assumptions. Specifically, statistically rare and large microstructural features, such as secondary phases or interconnected pores, become apparent, which 2D methods cannot reveal. The generated volumetric data can furthermore serve as quantitative reference datasets (i.e., the ‘ground truth’) essential for validating other 3D characterization techniques and computational models, helping to bridge the gap between predictive simulations and real-world material behavior. RASI’s modular design makes it a flexible tool that provides realistic 3D insights into materials, which can be used for advanced materials research, process optimization, and quality control. KW - 3D metallography KW - Automated microstructure characterization KW - Image segmentation KW - Mechanical polishing based serial-sectioning KW - Process-microstructure-property relationships KW - Quantitative microstructure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649614 DO - https://doi.org/10.1002/adem.202502202 SN - 1527-2648 VL - 28 IS - 2 SP - 1 EP - 14 PB - Wiley-VCH GmbH AN - OPUS4-64961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -