Fabricating spheroidal graphite piece e.g. circuit of exhaust gas engine made of metal or its alloy e.g. iron having internal space by smelting, comprises supplying materialized core in space, and covering core surface using dried powder

摘要

The process of fabricating a piece made of metal or its alloy having an internal space by smelting, comprises supplying a materialized core in the internal space, covering a surface of the core using a dried powder comprising an element capable of broadcasting to disseminate the metal or its alloy under the effect of heat, disposing the core in a mold, smelting the metal or its alloy, and flowing the molten metal or its alloy in the mold around the core so that the powder is cooled and then warmed by the molten metal or alloy. The process of fabricating a piece made of metal or its alloy having an internal space by smelting, comprises supplying a materialized core in the internal space, covering a surface of the core using a dried powder comprising an element capable of broadcasting to disseminate the metal or its alloy under the effect of heat, disposing the core in a mold, smelting the metal or its alloy, and flowing the molten metal or its alloy in the mold around the core so that the powder is cooled and then warmed by the molten metal or alloy, which causes the localized release of the metal or alloy in a diffusion zone surrounding the core. The step of covering a surface of the core comprises applying a refractory coating to the surface, and drying the refractory coating before flowing the molten metal or its alloy to the diffusion area. The core is washed off in a fluidized bed, where the powder is traversed by a gas stream. The coating is covered with a suspension of the powder in a liquid or gel. The particles of the powder have a size of 45-300 microns. The internal space of the piece is a conduit traversing the piece.