Investigation of Inner Vacuum Sucking method for degassing of molten aluminum

Hydrogen is a harmful gas element that is appreciably soluble in aluminum and its alloys. Removal of hydrogen from molten aluminum has been one of the most important tasks in aluminum melt processing. In this paper, a patented degassing process, which is based on principle of vacuum metallurgy, is proposed. A porous head that connects a vacuum system is immersed in the molten aluminum. The vacuum is created within the porous head and the dissolved hydrogen will diffuse unidirectionally towards the porous head according to Sievertʹs law. In this way, the hydrogen in the molten aluminum can be removed. The Fickʹs diffusion equation is used to explain hydrogen transfer in the molten aluminum. RPT experiments are carried out to evaluate the effectiveness of the new degassing process. The experiments indicate that the hydrogen content can be dramatically reduced by use of this process.