MANUFACTURE OF LOWWCARBON HIGHHCHROMIUM ALLOY STEEL BY HEATTINSULATED FURNACE FOR MOLTEN STEEL

摘要

PURPOSE:To manufacture the high quality alloy steel described in the title at a low cost, by transferring molten high-chromium alloy steel to a heat-insulated molten steel furnace having heating means, by heating the steel, and by adding a metallic oxide to the alloy steel in order to conduct decarburization under vacuum. CONSTITUTION:Molten, high-chromium alloy steel M, which has been roughly decarburized in an electric furnace 1, and subjected to the reduction of chromium with a reducing agent, is tapped to a ladle 3 for heat-insulated molten steel furnace provided with an inert gas blowing means. The alloy steel M contained in the ladle 3 is heated by a heating means 4 for heat-insulated molten steel furnace. After heating, a prescribed amount of metallic oxide 5 is added to the molten steel, and the molten steel is decarburized under vacuum while inert gas being injected through the bottom of the ladle 3. If necessary, the heating and the vacuum treatment are repeated. Slag formation is accelerated by the addn. of slag making agent 7 when the temp. is raised by heating. When the molten steel is heated to a prescribed temp., vacuum treatment, addn. of iron alloy for fine adjustment of composition, temp. control by the heating means are further conducted.