PRODUCTION OF INGOT HAVING SOUND INNER QUALITY

摘要

PURPOSE:To dilute concentrating component in molten steel and to obtain a sound ingot by using non-consumable type electrode during the initial period when holding heat in the poured molten steel is transmitted into a mold and the intermediate period when solidification progresses, and raising temp. during the latter period when the solidification reaches to the top part as progressing and also adding iron-series diluting material. CONSTITUTION:The non-consumable graphite electrodes 14 are submerged into slag 12 in hot top frame 6 by electro-slag-hot-top process(ESHT treatment) and connected with the power source 16. By slag joule heat with impression from the power source 16, the top part of the molten steel 8 in the mold 4 is heated to hold the heat thereof. The solidified skinning at the top part is prevented and while controlling development of porosity, the ESHT treatment is executed to over during the initial period and the intermediate period. Successively, at the time of coming in the latter period, wire- like iron series diluting material 18 for adjusting the component to be diluted in the molten steel 8 through the slag 12 is supplied for adding. By this method, while diluting the concentrating component at the top part in the molten steel, the ESHT treatment is executed and the ingot having sound inner quality with only a little defect can be obtd.