GB204110A - Improvements in or relating to the manufacture of steel - Google Patents

Abstract

204,110. Hadfield, Sir R. A. June 19, 1922. Alloys.-In the manufacture of flawless alloy steel, molten refined alloy or carbon steel or pure ingot or wrought iron is heated in a basic electric furnace, which is maintained in a sealed condition during the process, in the presence of a deoxidant other than carbon, such as ferro-silicon, or ferro-silicon and ferro-chromium and a slag forming material, and also carbon if desired. After heating for a considerable time, part of the slag is removed and a, deoxidant with other materials to form a reducing and refining slag is added and the heating continued until the molten metal has attained the desired degree of purity as regards sulphur and phosphorus. The additions to give the desired composition of the molten metal are then added and the resulting metal tapped, a small quantity of aluminium being added, if necessary, before or after the metal is tapped, or both. To cause a slow boiling of the metal bath in order to reduce the percentage of carbon to the desired degree, an oxidant, in small quantities at a time, may be added to the bath before adding the materials to produce the reducing and refining slag. To produce flawless nickel chromium steel, the charge comprises pure iron or pure iron and nickel or refined nickel chromium steel or refined nickel steel and nickel chromium steel with ferrochrome, carbon, ferro-silicon and lime. The refined steel used may be of the kind described in Specifications 142,885, 164,394, and 164,395, and the pure wrought iron may be of the kind known as Swedesh wrought iron.