| 摘要 |
<p>PURPOSE:To minimize a bottom unsound portion of an ESR ingot and enhance the yield of the ingot by making two consumable electrodes longer than one remaining electrode in starting to stabilize the starting. CONSTITUTION:Unmolten slag 2 is laid on the bottom of ingot case 1, and consumable electrodes 4, 5, 6 are arranged opposite to AC three-phase power source 3. Two electrodes 4, 5 are made longer than electrode 6, and tip portions 4', 5' of electrodes 4, 5 are reduced in cross-sectional area. In the early stage of starting, the tips of electrodes 4, 5 contacted to slag 2, and by resistance heating with source 3 slag 2 is melted. The tips of electrodes 4, 5 begin to melt with the heat of slag 2. When third electrode 6 contacts to slag 2 as the melting proceeds, source 3 is applied among electrodes 4, 5, 6, and by resistance heating as three-phase equilibrium load the molten state of slag 2 is maintained thereafter. Melting of electrodes 4, 5, 6 is also maintained, and molten metal 8 is stored under slag 2 and solidified to form ingot 9.</p> |
