US3517727A - Apparatus for continuously casting and refining a metal in a bottomless mold - Google Patents

Description

June 30, 1970 BABEL APPARATUS FOR CONTINUOUSLY CASTING AND REFINING A METAL IN A BOTTOMLESS MOLD Filed Dec. 27, 1967 United States Patent APPARATUS FOR CONTINUOUSLY CASTING AND REFINING A METAL IN A BOTTOM- LESS MOLD Louis Babel, Sauvigny-les-Bois, France, assignor to Societe Metallurgique dlmphy, Paris, France, a company of France Filed Dec. 27, 1967, Ser. No. 693,954 Claims priority, application France, Jan. 6, 1967,

Int. Cl. B2241 27/02, 11/10 US. Cl. 164250 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a process and apparatus for continuously casting and refining a metal.

According to the invention, there is provided a process for continuously casting and refining a metal comprising the steps of introducing slag into a cooled, bottomless, casting mould above the metal level, maintaining the slag in liquid form, and changing the slag by the addition and extraction of slag at a location above the liquid metal level.

According to the invention, there is also provided apparatus for continuously casting and refining a metal, comprising a bottomless mould in which the metal is to be cast, means for cooling the mould, means for introducing slag into the mould above the metal level in the mould, means for maintaining the slag in liquid form, and means for changing the slag in the mould.

Features and advantages of the invention will be apparent from the following description of an embodiment thereof given, by way of example, in conjunction with the accompanying drawings, wherein:

FIG. 1 is a vertical section through apparatus according to the invention, permitting continuous casting and refining of the metal, and

FIG. 2 is a section on a line II-1T in FIG. 1.

The apparatus shown in the drawings has a mould 1 of copper, cooled internally by Water circulating in ducts 2. The semi-finished metal product 3, obtained by solidification of the metal in the mould, is drawn downwards by a withdrawal machine, which may be of conventional type. The semifinished product includes a portion 4 which is still liquid and which is supplied by a feed jet 5. This jet, in a known manner, is eccentric relative to the product 3.

The installation also includes a duct 6 supplying a stream 7 of electrically conductive slag which goes on top of the product 3, forming a layer 8 protecting the metal.

The lower end of a metal mandrel 9, made of copper and cooled by a fluid coolant such as water circulating in internal ducts 10, dips into the layer 8 of electrically conductive slag.

3,517,727 Patented June 30, 1970 "ice An axial portion 11 of the mandrel forms a tube for extracting the slag from the layer 8. The slag is exhausted by a device 12, for example a pump or an extraction device with an ejector of a known type.

{The mould 1 and tubular mandrel 9 are connected to the terminals of an electric power supply, for example a single-phase alternating-current power supply.

Since the lower end of the-tubular mandrel 9 dips into the slag layer 8, the slag is kept in the liquid state by heating due to the Joule effect, the electric current passing between the mandrel 9 and mould '1.

The molten metal arriving in the form of a jet 5 traverses the slag layer 8 and flows, by gravity, to feed the liquid portion which is to form the semi-finished product by solidification. The slag is selected so that while the metal passes through it, the metal is subjected to the high degree of refining which reduces the contents of gas and certain other impurities such as sulphur, and which eliminates non-metallic inclusions.

The slag retains its effectiveness because it is continuously replaced, since the duct 6 supplies it above the semi-finished product formed and since it is continuously extracted by exhausting along the mandrel 9. The layer of electrically conductive slag must be thick enough to allow correct refining of the metal traversing it. A suitable thickness may, for example, be of the order of 100 mm. for a mould whose largest dimension is of the order of 200 mm.

The composition of the slag depends of course the refining required and the grade of steel cast.

It should be noted that the process improves not only the purity and quality of the steels or alloys cast, but also the quality of the casting skin.

What is claimed is:

1. Apparatus for continuously casting and refining a metal, comprising a bottomless mould in which the metal is to be cast, means for cooling the mould, means for introducing slag into the mould above the metal level in the-mould, means for maintaining the slag in liquid form, and means for changing the slag in the mould including a tubular mandrel for dipping into the slag and defining a duct for the passage of slag therethrough, and an extraction device connected to said duct to remove slag from the mould.

2. Apparatus as claimed in claim 1, wherein the means for maintaining the slag in liquid form includes a heating device.

3. Apparatus as claimed in claim 1, wherein the heating device comprises an electrical circuit connected to the tubular mandrel and to the mould, the slag being electrically conductive.

References Cited UNITED STATES PATENTS 3,411,566 11/1968 Astrou et al. 164281 2,369,233 2/1945 Hopkins 164-52 2,375,107 5/1945 Hopkins 164-82 X 3,234,608 2/1966 Peras 164-52 3,344,839 10/ 1967 Sunnen 164-52 J. SPENCER OVERHOLSER, Primary Examiner R. S. ANNEAR, Assistant Examiner US. Cl. X.R.

Images