Process and apparatus 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 hypoeutectic cast iron composition is used as a material, a melt of the composition is poured into the semi-solidified slurry producing vessel 30 in a predetermined amount at a time, a temperature of the melt when poured into the semi-solidified slurry producing vessel 30 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 30 is controlled not to exceed 20° C. per minute.

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 hypoeutectic cast iron composition 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 while being cooled and homogenized in the relay and damper vessel. 
     
     
         3 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 2 , wherein the melt received from the ladle is discharged from the relay and damper vessel via a discharge port provided at a bottom of the relay and damper vessel so that the melt continuously falls down into the semi-solidified slurry producing vessel while being cooled and homogenized in the relay and damper vessel. 
     
     
         4 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 3 , 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. 
     
     
         5 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 3 , wherein energy caused by the melt falling from the relay and damper vessel down into the semi-solidified slurry producing vessel is used to stir the melt within the semi-solidified slurry producing vessel. 
     
     
         6 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 1 , wherein the semi-solidified slurry producing vessel is pre-heated such that the melt poured in is cooled in the semi-solidified slurry producing vessel at a rate of not greater than 20° C. per minute. 
     
     
         7 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 6 , wherein for pre-heating the semi-solidified slurry producing vessel, the semi-solidified slurry producing vessel itself is subjected to high-frequency induction heating. 
     
     
         8 . The process for producing a semi-solidified slurry of an iron alloy according to  claim 1 , 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. 
     
     
         9 . An apparatus for producing a semi-solidified slurry of an iron alloy, comprising: melt pouring means capable of holding and pouring a melt of a hypoeutectic cast iron composition; and a semi-solidified slurry producing vessel configured to cool the melt poured therein to produce a slurry in a semi-solidified state; wherein
 the melt pouring means includes melt-pouring-temperature adjusting means for pouring the melt of the hypoeutectic cast iron into the semi-solidified slurry producing vessel by adjusting a temperature of the melt to be not lower than a crystallization initiation temperature of the melt and not greater than a temperature that is 50° C. higher than the crystallization initiation temperature, and   the semi-solidified slurry producing vessel includes cooling-rate adjusting means for cooling the received melt at a cooling rate of not greater than 20° C. per minute.   
     
     
         10 . The apparatus for producing a semi-solidified slurry of an iron alloy according to  claim 9 , wherein
 the melt pouring means is constituted by a ladle for receiving and delivering the melt from a melting furnace, and a relay and damper vessel placed above the semi-solidified slurry producing vessel and configured to once receive the melt from the ladle in a required, predetermined amount and then pour the received melt into the semi-solidified slurry producing vessel, and   the melt-pouring-temperature adjusting means has first temperature adjusting means for adjusting a temperature of the melt which is to be received in the relay and damper vessel such that the melt has a temperature within a predetermined temperature range at an outlet of the ladle, and second temperature adjusting means for adjusting a decrease in temperature of the melt which is cooled in the relay and damper vessel such that the melt has a temperature within a predetermined temperature range at an outlet of the relay and damper vessel.   
     
     
         11 . The apparatus for producing a semi-solidified slurry of an iron alloy according to  claim 10 , wherein the melt-pouring-temperature adjusting means has third temperature adjusting means for adjusting a decrease in temperature of the melt from when the melt is discharged from the relay and damper vessel until when the melt reaches the semi-solidified slurry producing vessel. 
     
     
         12 . The apparatus for producing a semi-solidified slurry of an iron alloy according to  claim 9 , wherein the cooling-rate adjusting means has pre-heating means for pre-heating the semi-solidified slurry producing vessel. 
     
     
         13 . The apparatus for producing a semi-solidified slurry of an iron alloy according to  claim 12 , wherein the pre-heating means of the semi-solidified slurry producing vessel includes high-frequency induction heating means.