PURPOSE: To obtain the optimum casting plan to the countermeasure of casting defects, such as shrinkage cavity, and a casting by executing the accurate solidification analysis under consideration of the solidifying process in the iron casting.

CONSTITUTION: The development and the growing velocity of graphite nuclei in the solidifying process in the iron casting are made to a model, and the radius and the number of grains of the graphite are calculated, and by the solidification analysis executing thermal calculation of undercooling degree based on the above calculating result, the casting plan for iron casting is designed.