Abstract

In melting aluminum and aluminum alloy, molten aluminum reacts readily with oxygen, cacbon monoxide and cacbon dioxide; it also reacts with adsorbed water, water present in hydrated oxide films on metal charges, water vapor in the atmosphere of the furnace to form oxides and hydrogen. As a result, a higher level of hydrogen is retained in the metal. In solid aluminum, hydrogen in excess of the solution limit can precipitate as H2 at grain boundaries. Thus, refining and degasifying can be improved mechanical properties of material.