GB888522A - Improvements relating to the degassifying of metals - Google Patents

Abstract

888,522. Degasifying molten metals. EDSTROM, J. O., and WIDMARK, G. H. Jan. 20, 1959. No. 2158/59. Class 72. Molten metals such as steel are degassed by a vacuum process in which the gases evacuated from the metal are chemically or physically bound by substances located at or near the upper surface of the metal. The gas binding substances may be metals, alloys, compounds, oxides or carbides such as Al, Mg, Ba, Sr, Na, Li, K, Fe, Zn, Mn, Ti, Ta, V, Cr, Zr, Mo, Si, and B; Ca Si, Ca Al, Fe Ti, Al Ti, Mg Al and Ba Al; the carbides of Al, Ca, Mg, Fe, Cr, Ti, Zr, Si and B or the oxides of Ca, Ba, Sr, Na, K, Mg and Mn or mixtures of these. The molten metal in a container 1 (Fig. 1) is enclosed in a vacuum chamber 3 and the reactive substances are enclosed in a section 6 which communicates with the vacuum space. A valve 7 controls the evacuation of the chamber and the occluded gases are absorbed or adsorbed in section 6, CO being removed as a carbonate, hydrogen as a hydride or hydroxide and nitrogen as a nitride or cyanide. Selective elimination of the gases may be effected and those gases not absorbed pass through section 6 and are removed by pumping. Several different forms of apparatus are exemplified and the vacuum chamber may completely surround the metal container (Fig. 1) or merely enclose the surface of the metal. The "vacuum pipette" method may also be used (Fig. 4) or the vacuum chamber 8 may be located or have an induction furnace 23 (Fig. 6).