PRODUCTION OF EXTRA-LOW SULFUR ALLOY

摘要

PURPOSE:To deoxidize, desulfurize and denitrify an Al-contg. alloy by adding powder consisting essentially of MaO and CaO in a vacuum state into the molten alloy in a melting furnace lined internally with refractories contg. a specific ratio of CaO. CONSTITUTION:The powder consisting essentially of MgO and CaO is added in the vacuum or non-oxidizing atmosphere into the molten alloy contg. Al in the melting furnace or vessel lined internally with the refractories contg. >=40% CaO. The MgO-CaO powder contg. about 17-75%, more particularly about 20-60% MgO and about >=15%, more particularly about >=40% CaO is preferably and is so added that the produced alloy contains 0.03-0.0001% Mg and 0.002-0.001% Ca. The pure alloy contg. about <=15ppm S, about <=20ppm O and about <=30ppm N is thus obtd.