抄録
Molten Cu alloys were cast into spheroidal graphite cast iron molds 180mm in inner diameter 300mm in outer diameter and 350mm in height and were pressed under pressures from 0 to 98MPa for 0 to 4min. The ratio of equiaxed grain zone in a micrograph of each ingot takes up about 65%. Remarkabiy fine equiaxed grains only form near the center of the ingot solidified under a light pressure 9.8MPa. When an ingot is pressed at a pressure over 40MPa for 4min, shrinkage defects significantly decrease. It is important to prevent shrinkage defects to keep the pressure higher than the strength of the ingot at relating temperatures till the ingot completely solidifies. The resultant ingot has excellent mechanical properties.
