GB437592A - Improvements in alloys and methods of preparing the same - Google Patents

Abstract

Alloys containing iron, nickel, chromium, and copper are prepared by fusing in a furnace, preferably an electric furnace, a charge containing iron or steel scrap, high carbon ferrochrome and oxides of copper and nickel to form a metal bath and a supernatant slag and then adding to the bath a suitable reducing agent to reduce the metal oxides in the slag. The nickel and copper oxides may be in the form of a calcined Sudbury ore and the scrap either low carbon steel scrap or iron-nickel-chromium-copper scrap of the same general analysis of the alloy to be made. The charge may also include a material high in iron oxide such as roll scale or magnetic iron ore concentrate. Before the reducing agent is added, the metal bath is superheated until the carbon content of the bath is at or below the desired maximum percentage of that element. The exothermic reducing agent such as ferro-silicon is added along with a basic agent such as burnt lime to reduce the chromium oxide present in the slag. The alloys produced contain 10-30 per cent of chromium a combined nickel and copper content of 7-26 per cent with the proportion of nickel to copper about 2 to 1 and the balance substantially iron. The alloys may contain less than 1 per cent of silicon, up to 3 per cent of other elements such as manganese cobalt, tungsten, and molybdenum either singly or in combination and up to 1 per cent of vanadium and titanium. The carbon content is preferably 0,05-0,15 per cent.