Browsing by Author "García, J. C."
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Item Caracterización de armas antiguas. Las inclusiones testigos de calidad, proceso y origen(2005) Rosado, G.; García, J. C.; Centros PRE-FUSION TECNALIA - (FORMER)This work shows the possibility of using new techniques to characterise archaeological items, from weapons to common objects. To sum up, data from weapons manufactured in different ages are shown, from an Iberian "falcata", to a Mondragón sword and also a more actual anvil. Preliminary steps are carried out to start an analysis of base material origin according to existing inclusions and to relate this with origin mineral and slag dumps where they were processed.Item Development of new Al-Si9Cu3 alloys for HPDC components with tailored properties(World Foundry Organization, 2014) Vicario, I.; Anza, I.; Sáenz De Tejada, F.; García, J. C.; Galarraga, H.; Merchán, M.; PROMETAL; CIRMETALAluminium high pressure die casting (HPDC) is the most common process in order to produce aluminium castings, due to the excellent balance of cost and properties for high series production volumes. The AlSi9Cu3 is the most common used aluminium alloy, representing approximately the 70% of the HPDC produced parts. AlSi9Cu3 alloys Nevertheless, conventional AlSiCu3 alloys present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of HPDC castings as well as the alloy composition. New process variants and alloys have been developed in recent years trying to improve these aspects. AlSi9Cu3 standards have a wide range for alloying elements, that can vary for example in the AlSi9Cu3(Fe) EN-AC 46000 from 8-11% in the Silicon alloying element. For HPDC the standard properties are Elongation (E) < 1%, Yield strength (Y.E.) 140 MPa, Tensile Strength (T.S.) 240 Mpa and Hardness <80 HB. The present work approaches the development of new alloys similar to the AlSi9Cu3 alloys, but with tailored properties in function of the desired requirements. Specific ranges of compositions provide improvements in the elongation, yield strength, ultimate tensile strength and hardness and also combinations of them. As cast properties shows an alloy with E > 1%, Y.S. >200 MPa, T. S. >320 Mpa and Hardness >135 HB.Item Equipamiento y metodología para la determinación de la vida de materiales para moldes(2010) Abuin, A.; Galarraga, H.; Crespo, I.; Plaza, L. M.; Carnicer, P.; Vicario, I.; García, J. C.; SG; CIRMETAL; PROMETAL; Tecnalia Research & InnovationDies used in the non ferrous die casting process, have a limited service life due to the damage effect by surface cracking appearance. These cracks are mainly produced by thermal fatigue, which are promoted by a repeated heating and cooling process through working cycles. The existing demand to improve materials to extend the die's service life leads to the development of new equipments to test the material behaviour. INASMET-TECNALIA in collaboration with FEAF (Spanish Federation of the Foundry Associations), has developed a testing machine to evaluate the thermal fatigue behaviour of steels used to manufacture dies. This testing machine is able to test forty samples simultaneously, getting a remarkable advantage in regard to previous developed test equipment. The versatility of heating and cooling system makes possible to test all kind of materials in very different thermal fatigue conditions.Item The use of new essay techniques to investigate the behaviour of austenitic steels with nano-alloys(World Foundry Organization, 2014) Caballero, P.; García, J. C.; PROMETAL; CIRMETALThe search for new applications of austenitic steel obliges us to develop new essay techniques which accept the addition of new nanoalloys and allow comparison with standard steels. The new essay techniques must facilitate the study of alterations, segregations and carbides in experimental nanoalloys. New applications will require new micro and macro structural characteristics; however, as the basic austenitic steel structure cannot be radically changed, obtaining improved mechanical properties is the challenge. Future uses of austenitic steel, due to its critical nature in diverse areas such as the aerospace industry and the electromagnetic sector, will require stringent controls. In order to meet these demands, new essay techniques are required. The successful development of new alloys depends on finding the correct element proportions and grain size of the nanoalloys to be added. Through the precise management of the basic steel and nano element mix, beneficial segregations, in both mechanical and rheological terms, can be produced for current and new applications. Thanks to its low cost and probable future use in a wide range of applications, our trials were conducted with manganese steel which was found to be a representative reference type for austenitic steel in general. Using X-ray diffractometry and cyclical fatigue, we have been able to demonstrate that each nano element can be assigned a specific residual tension. Based on this we have produced a table of mechanical properties by nano type which shows the effect of nano addition on the residual tension of the cast steel produced, and, consequently, on the mechanical properties of the experimental alloys. This allows the identification of the most appropriate alloy for both highly specific future and conventional applications of austenitic steels.Item Wire arc additive manufacturing of Mn4Ni2CrMo steel: Comparison of mechanical and metallographic properties of PAW and GMAW(2019) Artaza, Teresa; Suárez, Alfredo; Murua, Maialen; García, J. C.; Tabernero, Iván; Lamikiz, Aitzol; FABRIC_INTEL; FACTORY; CIRMETALWire arc additive manufacturing, WAAM, is a popular wire-feed additive manufacturing technology that creates components through the deposition of material layer-by-layer. WAAM has become a promising alternative to conventional machining due to its high deposition rate, environmental friendliness and cost competitiveness. In this research work, a comparison is made between two different WAAM technologies, GMAW (gas metal arc welding) and PAW (plasma arc welding). Comparative between processes is centered in the main variations while manufacturing Mn4Ni2CrMo steel walls concerning geometry and process parameters maintaining the same deposition ratio as well as the mechanical and metallographic properties obtained in the walls with both processes, in which the applied energy is significantly different. This study shows that acceptable mechanical characteristics are obtained in both processes compared to the corresponding forging standard for the tested material, values are 23% higher for UTS and 56% for elongation in vertical direction in the PAW process compared to GMAW (no differences in UTS and elongation results for horizontal direction and in Charpy for both directions) and without significant directional effects of the additive manufacturing technology used.