A STUDY ON DEGASSING OF ALUMINIUM CASTING ALLOYS

The problems arising from an excessive Hydrogen content in Aluminium castings are certainly well known. Research and development activities are continuously in progress, aimed at setting up devices for measuring, controlling and limiting the amount of Hydrogen in Aluminium casting alloys. In particular, attention is devoted to degassing systems and procedures, to be applied both during alloys production and in foundry. The evolution of the degassing process depends on several factors, including fluid-dynamics behaviour of the molten alloy, chemical and physical interaction between liquid metal, Hydrogen and degassing fluid, presence of impurities and so on. This paper presents the results of an experimental investigation carried out for evaluating the potential of Argon-SF6 mixtures in degassing Al-Si casting alloys