Browsing by Author "Arana, Jose Luis"
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Item Mathematical modeling of thermal-fluid flow in the meniscus region during an oscillation cycle(2006) Ojeda, Claudio; Sengupta, Joydeep; Thomas, Brian G.; Barco, Jon; Arana, Jose Luis; Centros PRE-FUSION TECNALIA - (FORMER)Item Model of thermal-fluid flow in the meniscus region during an oscillation cycle(2007) Ojeda, Claudio; Thomas, Brian G.; Barco, Jon; Arana, Jose Luis; Centros PRE-FUSION TECNALIA - (FORMER)Item Optimisation of total roll power using genetic algorithms in a compact strip production plant(2013) Marquez, Itziar; Arribas, Maribel; Carrillo, Ana; Arana, Jose Luis; CIRMETALThe application of optimisation techniques to hot rolling models can lead to the more efficient use of these models. In this work, a genetic algorithm has been used in order to design new hot rolling schedules with lower energy consumption through a reduction in the total roll power. Firstly, mean flow stress has been modelled for several Nb microalloyed steels produced in a compact strip production plant taking into account recrystallisation and precipitation models. The selected mean flow stress model has been validated against the values obtained from the industrial hot rolling forces using the Sims approach. Secondly, the model has been integrated with a genetic optimisation algorithm and new reductions have been proposed in order to decrease the total rolling power, maintaining all the requirements. The reductions achieved can be up to 10 %.Item Reinforcement of austenitic manganese steel with (TiMo) carbide particles previously synthesized by SHS(2009) Erauskin, Jose Ignacio; Sargyan, Ara; Arana, Jose Luis; Centros PRE-FUSION TECNALIA - (FORMER)The austenite of the Hadfield type manganese steels (1.0-1.4% C; 12-14% Mn), even though able to be hardened by impact, explosion, etc., is very ductile, tough and deformable, so that the industrial parts made with this material often suffer important geometric deformations during service. To minimize this problem, it is necessary to reinforce the austenitic matrix with hard, microscopic and dispersed ceramic particles, such as TiC, in order to increase the austenite stiffness while maintaining its toughness. Indeed, the development of a liquid metallurgy process enabling the reinforcement by means of the addition of the ceramic material to the molten metal in the melting furnace would become an important advance in this field. Nevertheless, these ceramic products are prone to the coalescence and have poor wettability by the molten bath, so that, their yield and the subsequent property improvement is very low. These disadvantages are solved if the ceramic particle is a complex carbide (TiMo)C bonded by metallic Fe, having a masteralloy of the Fe(TiMo)C type made by self-propagated high temperature synthesis (SHS). After that, its addition to the liquid austenitic manganese steel, the pouring of the mix (steel+carbides), its solidification, for example in sand molds, and the subsequent heat treatment (solution annealing and rapid quenching) produces composite castings or parts composed by an austenitic matrix and discrete carbide (TiMo)C particles inserted in it. This paper describes the process required to fabricate such a material and its characteristics.Item Wettability and mechanical properties assessment of Nano TiO2 and Armco Iron system(2011) Amondarain, Zuriñe; Kolbeinsen, Leiv; Arana, Jose Luis; Tecnalia Research & InnovationThe preliminary results of this investigation may help to determine the suitability of the TiO2 nanopowder to be added in a liquid iron based matrix in order to improve mechanical properties by a fine distribution of them in the metallic alloy. Further works include Armco Iron reinforcement by levitation melting furnace technique.Item Wetting behavior of sintered nanocrystalline powders by armco Fe and 22CrNiMoV5-3 steel grade using sessile drop wettability technique(2011-05-13) Amondarain, Zuriñe; Kolbeinsen, Leiv; Arana, Jose Luis; Tecnalia Research & InnovationThe wettability of sintered nanocrystalline oxide powders (CeO2, TiO2, Y3Al5O12, and ZrO2-yttria stabilized) and Al 2O3 basis powder (60-70% purity) (product originated in the secondary aluminium production, composed mainly of nano and micrometric aluminium oxide) by liquid Armco Fe and by 22CrNiMoV5-3 steel grade was studied using sessile drop wettability technique. The powders were pressed and sintered under different pressures, heating rates and holding times. The later grinding and polishing surface treatments were characterized by infinite focus microscope. The wetting experiments were carried out under pure Ar atmosphere. A small piece of Armco Fe and steel grade was melted on sintered nano oxides, heating up to 1 600°C with a holding time of 10 minutes for each experiment. The contact angles were measured and chemical analyses were conducted on tested samples to characterize the wetting reactions. It was found that sintered nano TiO2 not only suffered considerable wetting by Armco Fe and 22CrNiMoV5-3 steel in both cases, but also reacted with the substrate to form ilmenite and pseudobrookite. The CeO2 substrate and Armco Fe system also showed good wetting behavior. In general terms, it was concluded that wettability was affected by substrate chemical composition, and surface characteristics by sintering conditions. The preliminary results of this investigation may help to determine the suitability of the nanoparticle to be added in a liquid iron based matrix in order to influence the microstructure evolution improving mechanical properties by a fine distribution in the metallic alloy.