Browsing by Author "Gutiérrez, Teresa"
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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 Different Phenomena Encountered during Dilatometry of Low-density Steels(2021-11-22) Jimbert, Pello; Guraya, Teresa; Kaltzakorta, Idurre; Gutiérrez, Teresa; Elvira, Roberto; Tafaghodi Khajavi, Leili; CIRMETALIn recent decades, highly alloyed low-density steels are being developed to reduce the weight of different automotive parts. Dilatometry can be a very useful experimental technique to understand phase transformations during heating or cooling of new low-density steel alloys. When performing dilatometry measurements some assumptions are made such as the homogeneity of the sample material tested during the experiment. In this study, dilatometry tests were performed for two different low-density steels, and the variations of the composition between the surface and the inner part of the sample were analyzed. The migration of manganese by diffusion from the interior of the samples and finally its evaporation on the surface under vacuum were observed. This compositional gradient generated in the samples may influence the veracity and interpretation of the results obtained in dilatometry when working with high manganese steel alloys. The detachment of surface grains created by this compositional change near the surface of the samples is also investigated.Item Evaluating virtual reality and augmented reality training for industrial maintenance and assembly tasks(2015-11-02) Gavish, Nirit; Gutiérrez, Teresa; Webel, Sabine; Rodríguez, Jorge; Peveri, Matteo; Bockholt, Uli; Tecchia, Franco; CIRMETALThe current study evaluated the use of virtual reality (VR) and augmented reality (AR) platforms, developed within the scope of the SKILLS Integrated Project, for industrial maintenance and assembly (IMA) tasks training. VR and AR systems are now widely regarded as promising training platforms for complex and highly demanding IMA tasks. However, there is a need to empirically evaluate their efficiency and effectiveness compared to traditional training methods. Forty expert technicians were randomly assigned to four training groups in an electronic actuator assembly task: VR (training with the VR platform twice), Control-VR (watching a filmed demonstration twice), AR (training with the AR platform once), and Control-AR (training with the real actuator and the aid of a filmed demonstration once). A post-training test evaluated performance in the real task. Results demonstrate that, in general, the VR and AR training groups required longer training time compared to the Control-VR and Control-AR groups, respectively. There were fewer unsolved errors in the AR group compared to the Control-AR group, and no significant differences in final performance between the VR and Control-VR groups, probably due to a ceiling effect created by the use of two training trials in the selected task for participants who were expert technicians. The results suggest that use of the AR platform for training IMA tasks should be encouraged and use of the VR platform for that purpose should be further evaluated.Item Learning force patterns with a multimodal system using contextual cues(2018-02) Rodríguez, Jorge; Gutiérrez, Teresa; Portillo, Otniel; Sánchez, Emilio J.; CIRMETALPrevious studies on learning force patterns (fine motor skills) have focused on providing “punctual information”, which means users only receive information about their performance at the current time step. This work proposes a new approach based on “contextual information”, in which users receive information not only about the current time step, but also about the past (how the target force has changed over time) and the future (how the target force will change). A test was run to compare the performance of the contextual approach in relation to the punctual information, in which each participant had to memorize and then reproduce a pattern of force after training with a multimodal system. The findings suggest that the contextual approach is a useful strategy for force pattern learning. The advantage of the contextual information approach over the punctual information approach is that users receive information about the evolution of their performance (helping to correct the errors), and they also receive information about the next forces to be exerted (providing them with a better understanding of the target force profile). Finally, the contextual approach could be implemented in medical training platforms or surgical robots to extend the capabilities of these systems.Item Plant-wide interoperability and decoupled, data-driven process control with message bus communication(2022-03) Kannisto, Petri; Hästbacka, David; Gutiérrez, Teresa; Suominen, Olli; Vilkko, Matti; Craamer, Peter; CIRMETALConventional industrial communication systems suffer from rigidness, inflexibility and lack of scalability. The environment is heterogeneous as the systems exchange data with a variety communication protocols, some of which are proprietary. This makes it laborious and expensive to reconfigure or upgrade the systems. As the solution, this article proposes a message-bus-based communication architecture to enable information exchange between systems regardless of their geographical location and position within the functional hierarchy of the plant. The architecture not only enables communication to cross the conventional physical borders but also provides scalability to growing data volumes and network sizes. As proofs of concept, the article presents a prototype in three environments: a copper smelter, a steel plant and a distillation column. The results suggest that the message-bus-based approach has potential to renew industrial communications, a core part of the fourth industrial revolution.