Process for production of semisolidified slurry of iron-base alloy and process for production of cast iron castings by using a semisolidified slurry

A process for producing a semi-solidified slurry of an iron alloy by cooling an iron alloy melt in a semi-solidified slurry producing vessel to obtain a semi-solidified slurry having a crystallized solid phase and a residual liquid phase, the process comprising:

• using a material having a hypoeutectic cast iron composition;
• controlling a temperature of a melt of the material to fall within a specific temperature range of not lower than a crystallization initiation temperature of primary crystals in the composition and not greater than a temperature that is 50° C. higher than the crystallization initiation temperature;
• and adding, to the melt that is in the specific temperature range, an additive agent having a boiling point that is lower than at least the crystallization initiation temperature of the primary crystals, to thereby simultaneously conduct the stirring of the melt by the boiling of the additive agent within the melt and the cooling of the melt to a temperature falling within a semi-solidification temperature range thereof.