Patent ID: 6355089
Filing Date: 2002-03-12
Classification: C22B,C22C,Y02P,Y10T

Abstract:
A process for the manufacture of a carbon or low-alloy steel comprising:a carbon content of less than 1.5% by weight, alloy elements in a combined amount of less than 9% by weight, oxide and sulfide inclusions, wherein the chemical composition of the steel comprises, by weight: 0.1%&lE;Mn 0.01%&lE;Al&lE;0.05% 0.025%&lE;S&lE;0.3% 0.002%&lE;Ca 0&lE;0.0015% wherein a â€œKO oxideâ€  cleanness index is below 30, the oxide inclusions are lime aluminates, and an average calcium content of type 2, type 3, type 4 and type 5 inclusions is less than 30%:said process comprising:deoxidizing a molten steel with aluminum; degassing the molten steel under vacuum; injecting a powder comprising oxides whose melting temperature is below 1500Â° C. into the molten steel; and injecting calcium into the molten steel.