PURPOSE: To form finer crystal grains of an ingot by maintaining the rising rate of the molten metal surface by metal liquid drops in a casting mold at a specific value at the time of producing the metallic ingot by generating an are between two pieces of metallic electrodes and dropping the metal of the electrodes in the form of liquid drops into the casting mold.
CONSTITUTION: The electrodes 1, 2 are made of an Ni based super heat resisting alloy or other metals and the are 2 is generated by impressing a voltage between the two electrodes. The electrodes are melted by the heat of the arc and the liquid drops 3 thereof are dropped into the casting mold 4 consisting of BN, Si3N4, or high alumina refractories to form a half-molten metallic layer 5 which is then cooled from the lower part and the ingot 6 is cast. The rising speed of the surface of the half-molten metal 5 in the mold 4 is maintained at (10/D1/2W45/D1/2)/min where the diameter D obtd. by converting the section of the mold to the circle of the same area is expressed in cm. The fine crystal grains of the ingot 6 are thereby formed and the billet or ingot having excellent workability is obtd.
MIZUKAMI HIDEAKI
OZEKI AKIYA
