GB492896A - Process for degasifying and killing liquid steels - Google Patents

Abstract

Molten dephosphorized steel is degasefied and killed by introducing in the steel, while it is being poured into a receptacle, a reducing mixture, generally pulverised, comprising one or more reducing agents capable of fixing oxygen, and, if desired, of evolving heat and one or more substances capable of producing an evolution of gas thus ensuring ebullition of the bath and the formation of a slag with the reducing agent &c. The mixture may be placed in the receptacle and the steel poured on to it or may be introduced into the jet of metal while it is being poured. Simple or complex alloys such as silico-calcium, silico-aluminium, silico-titanium or ferro-silicon may be used as the reducing agents and the other substances alkaline compounds such as sodium or potassium carbonate, caustic soda or potash. Compounds such as siliceous sand, bauxite, fluorspar or ilmenite, which stabilize and slow down their decomposition, may be added to the alkaline compounds. Elements such as nickel, chromium, carbon, manganese, or silicon which it is desired to incorporate in the steel may be added to the mixture either in the form of alloys or of compounds. In one example, a mixture of 2,8 kilograms of silico-calcium, 3 of sodium carbonate and 0,8 of white siliceous sand is placed in a ladle and a metric ton of molten steel poured on to it. In another example, the mixture comprises 2,6 kilograms of silico-calcium, 3 of sodium carbonate 0,8 of white sand and 3 of ferro-chromium containing 0,1-0,2 of carbon.