Induction stirred, ultrasonically modified investment castings and apparatus for producing

摘要

A method for making an equiaxed investment casting. The method utilizes an ultrasonic generator to send an ultrasonic pulse into molten metal in an investment casting mold. The investment casting mold is positioned within a working zone of furnace having low output induction coils for generating a convection current in molten metal. The ultrasonic pulse separates dendrites growing from the face of the mold inward into the molten metal. Instead, equiaxed grains can nucleate within the molten metal. In addition, the ultrasonic pulse and the low output induction coils circulate the molten metal as solute is rejected from solidifying equiaxed grains. The mixing reduces the effects of segregation in the solidifying alloy and assists in nucleating equiaxed grains.

主权项

1. A casting unit comprising:
an investment casting mold having a mold cavity; a furnace having:
a first zone that receives the investment casting mold;low output induction coils for generating a convection current in molten metal in the mold when the mold is provided with molten metal;a refractory divider surrounding and defining the first zone; anda first heating element positioned within the first zone between the investment casting mold and the refractory divider, wherein the first heating element is separated from the low output induction coils by the refractory divider; insulation surrounding the furnace; and an ultrasonic source for delivering an ultrasonic pulse into the mold cavity when the cavity is provided with molten metal and positioned in contact with the bottom of the mold.