GB842588A - Improvements in and relating to a method and a device for casting steels and other ferrous compounds in ingot moulds - Google Patents

Abstract

842,588. Degasifying metals. DAUSSAN, H. . Jan. 28, 1958 [Feb. 26, 1957], No. 2792/58. Class 72 [Also in Group XXII] When casting ferrous metals the pouring jet is surrounded by a tube which is 'progressively destroyed by the metal bath in the mould which latter is closed around the tube, and a vacuum is maintained within the tube and the mould before and at the start of pouring. During subsequent pouring anc solidification the pressure of the gases emanating from the pouring jet and the meta: in the mould are regulated separately to degasify the metal, the tube forming a seal between the interior of the tube and the mould due to the delay in its destruction. A sheet metal tube 13 is sealed by an asbestos sleeve 14 to a hollow connecting head 18 clamped around the pouring opening 32, and to an annular cover 17 clamped to the mould 10. The head 18 is formed in two chambers b, c by a partition 30 having an opening 31 for the pouring jet, which opening is closable by a member 33. The mould space a, and the tube and head spaces d, b respectively are evacuable through connections 21, 40, and pressure gauges 23, 42, indicate pressures in said spaces. The bottom of the tube is initially seated on a disc 43, e.g. of fireproofed cardboard, which damps the pouring jet and floats on the melt around the tube until destroyed. The disc may also serve as a container of purifying, refining or addition products. In operation the mould and tube spaces &c. are evacuated and pouring started. The gases given off from the melt fill the vacuum and the vacuum connections are adjusted to obtain desired gas pressures, previously determined by experiment, to obtain a localization of impurities towards the centre. The pressure may also be varied, up and down, to vary the level of the melt 45 in the tube and thus obtain a stirring effect. After completion of pouring the aperture 31 may be closed by the member 33 and the mould and head assembly removed from the ladle and degasification continued during solidification. In a modification the hollow connecting head has only one chamber to which suction is applied, communicating with the mould space through perforations in the tube. In a further example the mould is bottom poured.