The dispersion of metallic fume generated from molten 80%Cu-10%Sn-10%Pb alloy is effectively suppressed by the double layer covering on the molten metal surface with two kinds of mineral powder. The suppression efficiencies are about 90% for lead fume, 70% for copper and tin fume. The tensile strength value, elongation value and hardness value of the alloy obtained from the suppression-treated melt are 25.8-28.1kg/mm2, 29.4-33.5% and 71.0-89.7 HB respectively. That is, the quality of alloy is not affected by the surface covering treatment.
