%0 Journal Article
%T Optimizaci車n del recorrido y de la potencia de un haz l芍ser de CO2 en el tratamiento t谷rmico de v芍lvulas de motores diesel
%A Amado
%A J. M.
%A 芍lvarez
%A C.
%A Nicol芍s
%A G.
%A L車pez
%A A. J.
%J Revista de Metalurgia
%D 2005
%I Consejo Superior de Investigaciones Cient赤ficas
%X In this article, a model for the process of CO2 laser treatment of diesel engine exhaust valves is presented. The treatment consists on the remelting of a nickel based alloy which has been previously plasma sprayed on the valve seat. Such process can be well described by means of a transient heat transfer equation, even if some numerical method must be applied when both temperature dependent thermophysical properties and realistic geometry description of the workpiece are taken into account. For this work the Finite Element Method, within the framework of ANSYS , was chosen, to solve that equation and this was done in the framework of ANSYS . The use of the process parameters previously assessed during a the theoretical and experimental study of box shaped workpieces requires a fine tuning based on simulation in order to be sure that the treatment of the valve seat gets comparable results to that of the flat workpieces. Among the important conditions to be satisfied stands the need for the temperature map to be parallel to the valve seat surface and so have the same treated depth. Besides, as the beam describes a circular path, coming back to the starting position, the initial temperature at that point will be higher than for rest of the workpiece. Therefore the beam power has to be optimized in order to get adapted to this new situation. Phase transition is included in the model by using the right thermophysical properties and a correct estimation of the effective absorption coefficients in both phases. This work shows the advantages of the process modelling to support the optimization of laser surface treatment of complex geometry workpieces using the model validation performed in simpler workpieces. En este trabajo se modeliza el proceso de tratamiento de v芍lvulas de motores diesel mediante l芍ser de CO2. Este tratamiento consiste en la refusi車n de una aleaci車n base n赤quel previamente proyectada por plasma sobre un asiento de v芍lvula. La resoluci車n de la ecuaci車n de conducci車n del calor se presenta complicada, en el momento en el que se incluyen propiedades termof赤sicas dependientes de la temperatura y una descripci車n realista de la geometr赤a de la pieza. En la modelizaci車n es necesario utilizar m谷todos num谷ricos y se ha escogido, en este caso, el M谷todo de los Elementos Finitos en el marco del programa comercial ANSYS . La aplicaci車n del estudio param谷trico, tanto num谷rico como experimental, previamente realizado sobre probetas planas a geometr赤as m芍s complejas, requiere de un ajuste fino de esos par芍metros para conseguir resultados comparables y trat
%K Laser remelting
%K Finite element modelling
%K Heat transfer
%K On-line monitoring
%K Valve
%K Refusi車n por l芍ser
%K Modelo de elementos finitos
%K Transmisi車n de calor
%K Monitorizaci車n en tiempo real
%K V芍lvulas
%U http://revistademetalurgia.revistas.csic.es/index.php/revistademetalurgia/article/view/1004/1017