Electroslag remelting of large solid ingots - where axial cooling device lowered into molten metal pool produces fine crystals in middle of ingot

摘要

One or more electrodes are melted in a chilled mould to form a cast ingot below a molten pool of metal, which is underneath a slag bath. A cooling device is lowered into the metal pool, and is then gradually raised at a speed corresp. with the vertical growth of the ingot up the mould. The cooling device is pref. immersed to max. 60% of the depth of the initial molten pool. Pref. cooling device consists of a float with a density higher than that of the molten slag but lower than the density of the molten metal so the float maintains a desired position during the process. With ingots over 1 m dia. and 2.5 m high, the cooling effect of the mould baseplate is inadequate, so coarse crystals are obtd. in the middle of the ingot. The invention eliminates this problem.