Browsing by Author "Martin, David"
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Item Austenite Reverse Transformation in a Q&P Route of Mn and Ni Added Steels(MDPI, 2020-06) Arribas, Maribel; Gutiérrez, Teresa; Del Molino, Eider; Arlazarov, Artem; De Diego-Calderón, Irene; Martin, David; De Caro, Daniele; Ayenampudi, Sudhindra; Santofimia, Maria J.In this work, four low carbon steels with different contents of Mn and Ni were heat treated by quenching and partitioning (Q&P) cycles where high partitioning temperatures, in the range of 550 °C-650 °C, were applied. In order to elucidate the effect of applying these high partitioning temperatures with respect to more common Q&P cycles, the materials were also heat treated considering a partitioning temperature of 400 °C. The microstructure evolution during the Q&P cycles was studied by means of dilatometry tests. The microstructural characterization of the treated materials revealed that austenite retention strongly depended on the alloy content and partitioning conditions. It was shown that the occurrence of austenite reverse transformation (ART) in the partitioning stage in some of the alloys and conditions was a very effective mechanism to increase the austenite content in the final microstructure. However, the enhancement of tensile properties achieved by the application of high partitioning temperature cycles was not significant.Item Characterization of a Medium Mn-Ni Steel Q&P Treated by a High Partitioning Temperature Cycle(2022-03-13) Arribas, Maribel; Del Molino, Eider; Gutiérrez, Teresa; Arlazarov, Artem; Martin, David; De Caro, Daniele; Ayenampudi, Sudhindra; Santofimia, Maria J.; CIRMETAL; PROMETALIn this work, a medium Mn-Ni steel was treated through Quenching and Partitioning (Q&P) with a partitioning temperature (PT) of 650 °C, which corresponded to the start of the austenite reverse transformation (ART) phenomenon. The influence of the quenching temperature (QT) and partitioning time (Pt) on austenite stabilization and mechanical properties was investigated. A strong influence of the quenching temperature was observed. Results were compared with those obtained after a Q&P treatment with 400 °C partitioning temperature. The Q&P cycle with quenching to room temperature and a high partitioning temperature produced a steel with a high retained austenite (RA) volume fraction and exceptional strength–ductility balance. The analysis of the mechanical stability of the retained austenite revealed a significant stress-induced transformation. Nevertheless, the austenite, which was stable at stresses above the yield stress, provided significant TRIP-assisted ductility. Bending, hole expansion and post-stamping properties were also evaluated for the most promising conditions.Item Recursos flexibles para la operación de las redes de distribución y transporte: proyecto CoordiNet(2020-01) Madina, Carlos; Gómez-Arriola, Inés; Chaves, Jose Pablo; Pardo, Miguel; Martin, David; Junco, Paula; Tecnalia Research & InnovationLa transición energética requiere de una adecuada coordinación entre el TSO y el DSO para el desarrollo y adquisición de nuevos servicios de flexibilidad en todos los niveles de tensión, a fin de integrar de forma segura y eficiente un volumen creciente de generación renovable en las redes de distribución y transporte. En este sentido, el proyecto CoordiNet está desarrollando diez proyectos de demostración en España, Grecia y Suecia, donde se analizarán diferentes alternativas para la compra de los nuevos productos y servicios de flexibilidad definidos en el proyecto. La presente comunicación presenta en detalle los demostradores españoles, liderados por Endesa y en los que participan Iberdrola y Red Eléctrica de España, además de varias empresas, centros de investigación y universidades.Item A Straightforward Methodology to Obtain the Power Coefficients Matrices for Unbalanced Distribution Networks to be Used in Flexibility Markets(IEEE, 2022) Cortés Borray, Andrés Felipe; Santos-Mugica, Maider; Gonzalez-Garrido, Amaia; Martin, David; Ojeda, Carlos; Borray, Andres Felipe Cortes; Tecnalia Research & Innovation; POWER SYSTEMSThe objective of the paper is to address the congestion problem in a specific distribution line by means of sensitivity coefficients seeking an intelligent a ctivation of t he available flexibility, based not only on economic a spects but also on the efficient use of flexibility. This paper proposes a straightforward methodology to obtain the sensitivity coefficient matrices for the unbalanced distribution networks, employing the perturb-and-observe (P & O) approach to assure an efficient usage of flexible resources. This means that a small change in the active power value of a particular flexibility provider, either load or generator, is applied to evaluate the power variation, therefore the loading variation, in every line of the system. The paper shows how these coefficients can be implemented in at heoretical energy market by the market operators by validating its application in an unbalanced network case and then compared with a real balanced distribution network. The simulations have been carried out in DIgSILENT PowerFactory through its API in Python.