PRODUCTION OF HIGH CARBON STEEL FOR ULTRAFINE WIRE ROD

摘要

PURPOSE:To obtain a titled steel for a tire cord with which the number of disconnection during cold drawing is extremely small by exposing partly the surface of a molten steel to air in the stage of treating the same with a flux under stirring with Ar without subjecting said steel to a vacuum treatment thereby adjusting the activity of the SiO2 of the slag. CONSTITUTION:A carburizing material and alloy material are usually added to a molten steel in the stage of tapping the molten steel from a converter to a ladle 1 and at this same instant a synthetic flux of CaO-SiO2 base having >=0.4 activity of SiO2 at the treating temp. of the molten steel is added to the molten steel in the ladle at >=2kg for each 1 ton of the molten steel. A small amt. of the converter slag flowing out unavoidably into the ladle mixes with the synthetic flux in this stage to form the slag on the bath surface of the ladle. Gaseous Ar is then blown to the molten steel 2 by a lance 4 attached concentrically with a refractory ring 5 by a supporting arm 6 and the molten metal surface part where the gas rises is enclosed with the ring 5. The molten metal part is exposed to air to stir and treat the molten metal. The molten metal is thereafter subjected immediately to continuous casting without degassing the same and is thus made into a casting billet.