Cast iron improvement by oxygen lancing

Abstract

The use of oxygen in the manufacture of cast iron has nCR been panicularly put into practice. However, an investigation into utilization of oxygen to improve cast iron has been conducted for several years in the authors' company's laboratory. The treatment of lancing oxygen into molten iron decreased coments of carbon, silicon, manganese and other harmfu l elements for the formation of nodular graphite, such as ti tanium, and did not have the harmful influence of oxidation on the iron. Therefore, the above treatment cduld be adopted for the improvement of pig iron for ductile iron and the manufacture of various cast irons. For instance, even pig iron, havi ng some quantities of elements such as Litanium which disturbed the formation of nodular graphile brought about by magnesium addi tion , easily formed spheroidic graphite by magnesium addi tion after the oxygen lancing treatment. Cast irons treated by injection of oxygen showed superior properties in the uniformity o[ graphite distribution, the tensile strength and the influence of mass effects. For the purpose of oxygen treatment of cast iron the foundry converter has been used, by which various cast irons have been made from cupola irons. The converter is especially suitable [or the manufacture of chilled castings which have comparatively low silicon content. The coll trol of the chemical composition in the irons is not so difficult when the conditions, such as the chemical composition and the temperature of cupola iron, the tem perature of preheated converter, etc., are known . The manufaC LUre of cast irons by the converter i ~ easier and more economical, compared with the process of electric arc furnace and reverherator, because the refining time is shorter.