GB879670A - Improvements in or relating to the production of metal ingots and castings - Google Patents

Abstract

879,670. Casting processes. INCA STEEL CO. Ltd. Sept. 23. 1959 [Oct. 2, 1958], No. 31531/58. Class 83 (1). A casting with an equiaxed crystal structure free from major segregation is made in a mould which is itself formed of, or the walls of which are wholly lined with a combustible composition which, on firing generates by its exothermic reaction sufficient heat to prevent, or substantially prevent, initial chilling of the melt and to delay cooling, the base of the mould being formed of or lined with the combustible composition or a heat-insulating material, and a combustible composition or heat-insulating material being applied to the surface of the melt. The exothermic composition may include aluminium powder &c. with one or more oxidizing agents such as alkali metal, nitrates, iron oxide, manganese oxide. and include a fluoride of alkali metal, sodium aluminium or potassium aluminium, silico- and boro-fluorides, together with a filler such as sand or grog and a binder such as sulphite lye, gum arabic and clay. Carbonaceous compositions based e.g. on charcoal or coke, and sand impregnated with oil may also be used. The exothermic lining may be backed by a refractory lining having vents communicating with vents in the mould and may be preformed. The facing surface of the exothermic material may be covered with a thin metal-impervious lining of e.g. mica, graphite, silica flour, cement in a carrier such as a resin solution, hardboard, cardboard, paper, glass, fibreglass.