Browsing by Author "Arana, J. L."
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Item Laser polishing of tool steel with CO2 laser and high-power diode laser(2010-01) Ukar, E.; Lamikiz, A.; López de Lacalle, L. N.; del Pozo, D.; Arana, J. L.; SGThis paper presents the effect of the laser-polishing process applied to a milled and EDMed surface of DIN 1.2379 tool steel commonly used in the die and mold industry. The martensitic structure of this type of steel (showing hardness values up to 62 HRC) makes the polishing operation extremely difficult. At present polishing must be carried out manually by skilled workers, and this entails an expensive and prolonged process. An alternative to automation of the polishing process is a laser-polishing process, based on tightly controlled melting of a micro-layer of surface material which flows into and fills topographic valleys for a smoothed surface topography. Thus the main process parameters have been identified and optimized using two different types of industrial laser: a CO2 laser and a high-power diode laser (HPDL), obtaining up to 90% roughness reduction with mean roughness values (Ra) below 0.5 μm. Moreover, in order to secure a complete study of the process in accordance with the energy radiated, three-dimensional topographic surfaces were measured and a metallurgical study performed to determine the effect of laser radiation on the structure of the material.Item Mechanical properties and phases derived from TiO2 nanopowder inoculation in low carbon steel matrix(2013) Amondarain, Z.; Arribas, M.; Arana, J. L.; Lopez, G. A.; Tecnalia Research & Innovation; CIRMETALThe effect of TiO2 nanoparticle addition on mechanical properties of low carbon steel and the phases originated from this inoculation were investigated. Equilibrium phases were estimated by means of thermodynamic modeling and the results were compared with further microscopy characterization. Both techniques confirmed the dissolution of TiO2 nanoparticles in the molten steel which derived in TiN and Ti4C2S2 nanometric reaction products. The formation of these nanometric phases, were found to result in ferrite grain refinement and consequently in the enhancement of mechanical properties. In addition, the formation of these phases led to C and N depletion from the iron matrix and to a continuous yielding behavior in tensile stressstrain curves.Item Sintesis autopropagada a alta temperatura (SHS) del masteralloy Fe(TiMo)C utilizando ferroaleaciones(2009-05) Erauskin, J. I.; Sargyan, A.; Arana, J. L.; Centros PRE-FUSION TECNALIA - (FORMER)Titanium monocarbide TiC is very hard, stable both at high and low temperatures and relatively easy to synthesize from its constituent elements by SHS. Nevertheless, it is difficult to use, as alloying element, in the reinforcement of steels manufactured by liquid metallurgy due to its low wettability by molten steel. To achieve this purpose and due to its better wettability, it is more appropriate to use a master alloy formed by the complex carbide (TiMo)C bonded in Fe. The simplest and most economic way to fabricate such a master alloy Fe(TiMo)C is, again, by SHS, with the added advantage that it can be manufactured using the commercial ferroalloys FeTi and FeMo instead of the individual elements Fe, Ti and Mo. In this work, we describe such a process as well as the characteristics of the master alloy obtained.