PURPOSE: To enable the foamed metal of the specified and uniform cell size to be obtained by blowing microbubbles in place of foaming agents into the molten metal.
CONSTITUTION: Alloy 3 is melted by the crucible 2 in a melting furnace 1. When it reaches the temperature higher than its solidification temperature, the preheated bubble generator 5 is loaded into the molten alloy 3 and inert gas is blown through a vent pipe 4. Thence, pouring into an ordinary CO2 mold is done at the time when the microbubbles 6 of the inert gas have been sufficiently blown into the molten alloy 3. Here, the bubble generator 5 comprises closely fitting a cylindrical sintered filter 9 made of stainless steel to the vent pipe 4 having a stop metal 7 and provided with a plurality of vent pores 8 and securing the same by means of a bolt 10. Besides this, the similar effect is obtained even by using the one comprising securing a porous filter made of graphite or heat-resistant filter paper and stainless steel metal gauze to the vent pipe.
KOUMOTO AKIRA
ONO SHIYUUJI
