SE508311C2 - Method and apparatus for directly casting thin metal strips - Google Patents

Abstract

Thin metal strips, for example wide carbon steel strips, are cast in a single belt machine. The width of the molten metal on the belt is defined by side dams (12, 13) on the belt (11). The side dams have inwardly directed surfaces against the molten metal which makes the surface of the molten metal even also at its edges.

Description

508 311 which acts as a distributor of molten metal by having a plurality of cubes (ceramic outlet nozzles) distributed over the width of the belt 11 so as to provide a plurality of free jets 30 of molten metal hitting the belt 11 which moves as indicated by the arrow 15. The dice should be placed so that the molten metal flows out to a smooth layer 29 of metal which solidifies as a cast strip on the substrate, ie on the movable strip 11. A container 16, which may be, for example, an oven or a ladle, supplies a controlled flow of molten metal to the ladle / distributor 14.

The outflow from the container can be regulated in various known ways, for example with a stake winch or a rotary dice.

Figures 3 and 4 show a slightly modified embodiment of the machine shown in Figure 1. The container 16 is replaced with a rotatable tube 17 of the type shown in WO 9301015. The level of melt in the tube is kept constant with a control equipment (not shown) which regulates the supply to the tube. . The pipe 17 has an outlet 18 in the form of a gap and the flow out of the pipe can be regulated by rotation of the pipe because the rotation changes the ferrostatic pressure which drives the outflow from the gap 18.

The casting box 14 has two solid walls 20,21 which calm the flow and cause the flow to become laminar before it reaches the dice 22. The endless belt 11 is cooled by a large number of cooling nozzles 23 spraying water towards its underside so that the effluent melts to solidify. a cast strip.

Since the endless belt 11 moves rapidly when the vertical parallel jets 30 from the casing cubes 22 hit the belt 11 and the melt does not wet the belt 11, the melt will not flow out backwards so no rear dust is required. The distance between the jets 30 must not be greater than that the melt flows out as an evenly thick layer before it solidifies. There is no contact between the casting box / distributor 14 and the endless belt 11 and its side dams 12,13 which is an advantage especially when finishing a casting or if the casting process goes wrong, as there is no risk of freezing. The rays are shown vertically, but can also be inclined.

You can also easily and quickly and without major production loss change casting box / distributor 14 when changing bandwidth or change to a casting process that requires other dice or other number of dice because the casting sled is completely free both from the endless belt 11 and the container 16 and 17 respectively. dice and their outlet size need to be varied with regard to, among other things, casting width, casting speed, viscosity and desired thickness of the strip.

Figure 1 and Figure 3 show the side ponds 12,13 with enclosing walls. Figure 4 shows schematically and not to scale a metal strip cast with the machine shown in the figures. Through the inclusion of the side dams, a horizontal metal surface has been created in the line where solids (the dam), melt and gas (argon) meet. If the surfaces of the ponds were vertical, there would be a downward deflection on the surface because the melt does not wet the pond. Especially in combination with adding the melt in the form of a number of free rays, you get a very even and flat surface on the cast strip.

By canceling the effect of the surface tension in the strip edge in this way, it is also possible to cast thinner strips than has been possible so far.

It must be understood that the figures are schematic and fragmentary. Thus, for example, the necessary incorporation is not shown which allows the free jets of narrow metal and the effluent metal to be protected by an inert atmosphere, for example argon. The strip casting machine can be manufactured in different sizes and for different types of metals and alloys. It can be adapted, for example, for casting carbon steel 1 strip thicknesses down to about 6 mm and in strip widths of 1-2 meters. Although the invention has been exemplified by a single belt machine, the invention nv 508 311 q can be applied to other types of belt casting machines, for example single wheel machines.

Claims (5)

s S08 511 Patent claims A strip casting machine comprising a cooled and motorized endless belt (II) with side dams (12, 13> and a device (14) for supplying molten metal to the top of a flat and substantially horizontal part of the endless belt, characterized in that the side dams ( l2, l3) have inclined sides. Machine according to claim 1, characterized in that the endless belt lacks rear dust and a distributor (14) is arranged to supply a plurality of jets of narrow metal directly against the endless belt. Machine according to claim 2, characterized in that the distributor consists of a casting ladle (14), which is supplied with narrow metal from a container (16) with an adjustable utilode. 4. A method of directly casting thin metal strips by attaching narrow metal to a cooled and motor-driven endless strip (11), limiting the spread of the metal malt laterally with side dams <12,13, characterized in that side dams (11, 12) are used with inclined sides and adjusts the slope to the wetting angle so that the surface of the melt becomes substantially flat. Method according to claim 4, characterized in that the melt is supplied to the endless belt (II) in the form of a plurality of free jets (30) which lie so close that the melt flows out and solidifies as an even layer on the belt.