Patent ID: 6254661
Filing Date: 2001-07-03
Classification: B22F

Abstract:
A method of producing metal powder by atomizing molten metal, the method comprising:supplying a flow of molten metal down through a center of an orifice defined by a nozzle, wherein the nozzle includes a continuous ring-shaped slit located below the orifice;spouting a jet of liquid, having a shape of an inverse cone, from the slit and into an ejector tube disposed below the slit;sucking gas through the orifice of the nozzle, wherein the surface of the nozzle forming the orifice has a streamlined shape and is located above the slit;splitting the molten metal by an abrupt expansion of the gas in the vicinity of an exit of the orifice; andfurther splitting the split molten metal into fine particles by the jet of liquid,wherein the slit has a diameter of 50 to 150 mm, the inverse cone of the liquid jet has an apex angle of 10 to 80 degrees, the ejector tube has a diameter that is not less than 1.5 times the diameter of the exit of the orifice, the ejector tube has a length that is not less than a height of the liquid jet cone, the liquid is spouted at a flow rate of 300 to 1000 l/min, a pressure of the liquid is not less than 200 kgf/cm.sup.2, and a diameter of the orifice at the exit is sized so that the gas flows out of the orifice near or equal to the velocity of sound.