To suppress deposition of an added component or an impurity in lead onto a screw surface and to smoothly conduct extrusion by imparting vibration to either a housing or a screw and arranging an oscillation means to give vibration on lead or lead alloy in the housing.
A frequency of an oscillation means is preferably set to ≥0.1/min to ≤100/min, further a number of revolution of a screw is preferably set to ≥3/min to ≤30/min. When lead or lead alloy ascends in a flow passage of a housing by the screw 4, lead or lead alloy is solidified at a surface of the screw 4. At this time, vibration of an oscillator 7 is transmitted to the lead or lead alloy before solidifying through the screw 4, many crystal nucleuses are formed in a molten metal of lead or lead alloy. The crystal produced is refined to increase a crystal boundary, an added component or an impurity is integrated into lead or lead alloy as much as possible.
MIMURA SHOJI
TANABE NOBUO
Next Patent: EXTRUDING METHOD