Agency of Industrial Science and Technology Ministry of International

Kiyoshi Ichikawa

Masahito Katoh

A method of manufacturing metallic materials with extremely fine crystal grains comprises the steps of: taking molten metallic material that was melted by heating in a melting chamber and introducing it into an agitation chamber from said melting chamber, and in this agitation chamber, agitating it for 60 seconds or less by means of a screw-shaped stirring rod that is driven to rotate at 500 rpm or greater, and extruding the metallic material in the state of solid-liquid coexistence from an extrusion nozzle on the outlet side, and quench-solidifying the metallic material in the state of solid-liquid coexistence extruded from said nozzle immediately while it still has fine crystal grains as it is continuously formed into the desired shape. In this method, the speed of rotation of the screw-shaped stirring rod may be 800 to 1000 rpm. Also, the time in which the metallic material resides in the state of solid-liquid coexistence may be 5 to 60 seconds.

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Tsuchiura, Japan

Kiyoshi Ichikawa