Deoxidising, desulphurising and refining steel - by means of a liquid slag and aluminium additions

摘要

The deoxidation, desulphurisation and refining of steel in a casting vessel involves the injection of Al, an alkaline-earth and of other powder products into a vessel provided with a basic lining. Before the metal is cast, a predetermined quantity of a fluid basic slag is provided in the base of the vessel, the slag being free of oxides and sulphates and eventually contg. deoxidising and refining agents so that a slag is formed contg. little iron and other oxides, but rich than normal. The process further involves casting the metal while avoiding the arrival of the converter refining slag, stirring the metal and the slag deoxidised by means of argon; and adding Ca alloys in several stages and as near as possible to the base of the vessel. The process (a) reduces the residual quantity of Al in the steel (b) reduces the sulphur content in the steel (c) reduces the quantity of non-metallic inclusions, (d) enables the clean metal with increased castability at a controlled casting temperature.