Abstract:
The invention relates to a method for melting scrap consisting of alloy components containing lithium. According to said method, (i) scrap containing aluminium-lithium-type alloys is collected (collection step); (ii) an initial bed of a liquid metal consisting of a first composition is prepared in a smelting furnace (preparation step for the initial bed of liquid metal); (iii) the scrap is loaded onto the initial bed of liquid metal in such a way as to create a floating blanket of the scrap with a controlled thickness on the surface of the bed of liquid metal (loading step), said blanket partially melting as it comes into contact with the bed of liquid metal in such a way as to obtain a bath of liquid metal consisting of a second composition that can be the same as, or different from, the first composition, and the lithium content of the bath of liquid metal consisting of a second composition amounting to between 0.1 %, preferably 0.2 %, and 2.5 % wt. % of the total weight; and (iv) the liquid metal is extracted (extraction step) from the bath of liquid metal consisting of a second composition. The inventive method is technically and economically advantageous in that it does not require investment into a particular installation, especially containing an inert atmosphere, and it does not require, or at least minimises, the use of expensive consumables such as inert gas, as the formation of a blanket of scrap with a controlled thickness enables the surface of the liquid metal to be protected from oxidation in a surprisingly efficient manner.
Abstract:
Procédé de fusion de scrap en alliage d'aluminium contenant du lithium dans lequel (i) on approvisionne du scrap contenant des alliages de type aluminium-lithium (étape d'approvisionnement) ; (ii) on prépare un lit initial de métal liquide d'une première composition (étape de préparation du lit initial de métal liquide) dans un four de fusion ; (iii) on charge ledit scrap sur ledit lit initial de métal liquide de façon à créer à la surface dudit lit de métal liquide un matelas flottant d'épaisseur contrôlée dudit scrap (étape de chargement), ledit matelas fondant partiellement au contact dudit lit de métal liquide de façon à obtenir un bain de métal liquide d'une seconde composition pouvant être égale ou différente de la première composition , la teneur en lithium dudit bain de métal liquide d'une seconde composition étant comprise entre 0,1% et préférentiellement 0,2% à 2,5% en poids ; (iv) on prélève le métal liquide (étape de prélèvement) dudit bain de métal liquide d'une seconde composition. Le procédé selon l'invention présente des avantages techniques et économiques : - il ne nécessite pas d'investir dans une installation particulière, notamment à atmosphère inerte, - il ne nécessite pas, ou il minimise l'utilisation de consommables onéreux tels que du gaz inerte, car la formation d'un matelas de scrap d'épaisseur contrôlée permet de protéger de l'oxydation la surface du métal liquide d'une façon étonnement efficace.
Abstract:
Method for adjusting the level of the contact line of the free metal surface with the ingot mould (c) in a continuous vertical casting. The method comprises the application to the liquid in the course of its solidification of a variable periodic magnetic field of which the direction (9) is substantially parallel to the axis of the ingot mould (3) and the adaptation of the intensity of said field as a function of the desired level. It finds its application in the casting of metallurgical semi-products particularly of aluminium and alloys thereof such as lithium alloys and wherein the aim is to obtain a cortical zone of zero thickness, a fine grain without previous addition of refining agents and an absence of barbs.