Process for producing semi-solidified slurry of iron alloy

Abstract

A process for producing a semi-solidified slurry of an iron alloy including the steps of pouring a melt of an iron alloy into a semi-solidified slurry producing vessel 30 and cooling the melt therein to obtain a semi-solidified slurry having a crystallized solid phase and a residual liquid phase, wherein a hypereutectoid or hypoeutectic cast iron composition containing 0.8-4.3 wt. % C is used as a material, a melt of the composition is poured into the semi-solidified slurry producing vessel in a predetermined amount at a time, a temperature of the melt when poured into the semi-solidified slurry producing vessel is controlled to be not lower than a crystallization initiation temperature of the composition and not greater than a temperature that is 50° C. higher than the crystallization initiation temperature, and a cooling rate of the melt poured into the semi-solidified slurry producing vessel is controlled not to exceed 20° C. per minute.

What is claimed is: 
     
         1 . A process for producing a semi-solidified slurry of an iron alloy comprising the steps of: pouring a melt of an iron alloy into a semi-solidified slurry producing vessel; and cooling the melt in the vessel to obtain a semi-solidified slurry having a crystallized solid phase and a residual liquid phase; wherein
 a hypereutectoid or hypoeutectic cast iron composition containing 0.8-4.3 wt. % C is used as a material, a melt of the composition is poured into the semi-solidified slurry producing vessel in a predetermined amount at a time, a temperature of the melt when poured into the semi-solidified slurry producing vessel is controlled to be not lower than a crystallization initiation temperature of the composition and not greater than a temperature that is 50° C. higher than the crystallization initiation temperature, and a cooling rate of the melt poured into the semi-solidified slurry producing vessel is controlled not to exceed 20° C. per minute.   
     
     
         2 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 1 , wherein above the semi-solidified slurry producing vessel, the melt poured from a ladle is once received in a relay and damper vessel in a predetermined amount at a time, and the melt received in the relay and damper vessel is then poured into the semi-solidified slurry producing vessel via a discharge port provided at a bottom of the relay and damper vessel, a diameter of the discharge port is not less than 10 mm, a temperature of the discharged melt at the discharge port is controlled to be not lower than a temperature that is 20° C. higher than the crystallization initiation temperature of the composition and not greater than a temperature that is 80° C. higher than the crystallization initiation temperature, a preheating temperature of the semi-solidified slurry producing vessel is not less than 400° C. lower than the crystallization initiation temperature of the composition and not greater than a temperature that is 200° C. higher than the crystallization initiation temperature, and a height of the relay and damper vessel from the semi-solidified slurry producing vessel is not less than 100 mm. 
     
     
         3 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 2 , wherein the melt is cooled by wind while the melt is falling from the relay and damper vessel down into the semi-solidified slurry producing vessel. 
     
     
         4 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 2 , wherein energy caused by the melt falling from the reply and damper vessel down into the semi-solidified slurry producing vessel is used to stir the melt within the semi-solidified slurry producing vessel. 
     
     
         5 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 2 - 4 , wherein a semi-solidified slurry produced is taken out in the state where the semi-solidified slurry producing vessel is heated by high-frequency induction heating such that part of the semi-solidified slurry that is in contact with the semi-solidified slurry producing vessel is heated via the semi-solidified slurry producing vessel.