JPS61262450A - Continuous casting method for molten metal - Google Patents

Abstract

PURPOSE:To cast continuously a clean and smooth metallic product having less oxidation on the surface by holding molten glass and molten metal in a vessel, pulling up the molten metal via the molten glass by a nozzle and cooling forcibly the same. CONSTITUTION:The molten metal and molten glass are poured into a refractory vessel 9 and are maintained at a prescribed temp. The nozzle 7 is lowered by a nozzle holder 6 into the molten glass layer in the upper part. The nozzle 7 is closed by a dummy bar 15 and after the nozzle 7 is lowered down to the prescribed position of the glass layer, the bar 15 is gradually raised. The molten metal is then pulled up by the nozzle 7 and the cooling of the nozzle 7 inside is changed from air cooling to mist cooling. The pressure in the vessel 9 is increased by a regulating valve 3 and the nozzle position is raised, then the stationary operation is started. The product is pulled upward by a take-up roll 13. The thickness and solidififed position of the product are detected and the product having the specified thickness is obtd. by adjusting the pressure and the nozzle position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is applied to manufacturing products of metals, particularly difficult-to-process metals.

(Prior Art) A continuous casting method using a water-cooled mold is generally used to solidify molten metal to obtain slabs of a certain shape.

On the other hand, recently, a method has been proposed in JP-A-58-1840 in which the mold is not cooled (on the contrary, it is kept in a heated state, and the metal is solidified directly above the mold or just before it leaves the mold).
This is proposed in Publication No. 43.

(Problem to be solved by the invention) In the former method using a water-cooled mold, the surface shape of the slab is not sufficiently smooth and is oxidized and cannot be directly used as a product. I had to process it.

The latter method also requires that the pulling rate be accurately synchronized with the solidification rate, and the metal surface is covered with an oxide layer, especially when the surface area is large, such as sheet, foil strip, or wire. There are disadvantages such as the ratio of the surface of the piece being covered with an oxidized layer increases, and the casting of ultra-thin foil strips or ultra-fine wire rods is difficult due to limitations in the outlet width or diameter of the slab.

The object of the present invention is to provide a method in which the surface of the slab is sufficiently smooth, there is no possibility that the surface will be oxidized, and even an extremely thin foil strip or an extremely fine wire can be cast.

(Means for Solving the Problems) The present invention, as shown in FIG. By placing the nozzle opening in the nozzle and applying suction from the outside of the nozzle or pressurizing the inside of the container, molten glass and molten metal are simultaneously discharged from the nozzle in such a way that the outer glass covers the inner molten metal. The purpose is to solidify the molten metal immediately after it exits the nozzle.

(Function) In the present invention, as shown in Fig. 3a, high-density mercury and high-viscosity glycerin are placed in a closed container, the tip of the nozzle 4 is immersed in the glycerin, and then the inside of the device is pressurized with compressed air. This invention was based on the knowledge that by adjusting the pressurizing pressure and the position of the nozzle tip, mercury can be discharged out of the container together with glycerin, as shown in FIG. 3b.

Based on this knowledge, by replacing glycerin with glass and mercury with molten metal, we were able to achieve a state in which the metal was continuously encapsulated in glass in a molten state.

Further, the shape of the nozzle can be any shape such as a slit shape or a circle.

In addition, the thickness of the metal (thickness in the case of wire) is determined by the proportion of glass and molten metal in the nozzle, so in order to keep the shape of the metal constant, it is necessary to keep the ratio of the two constant. There is. Increasing the extrusion pressure of the molten metal increases the discharge rate and increases the proportion of molten metal. On the other hand, if the nozzle is moved away from the molten metal surface, the proportion of glass increases but the proportion of molten metal decreases, making it possible to reduce the thickness or diameter of the product. Therefore, by appropriately controlling the extrusion pressure and nozzle position, a constant product can be stably obtained.

Furthermore, as a result of various experiments, it was found that the nozzle shape also has a large effect on the stability of the product shape.

When we tried changing the ratio between the opening thickness D of the circular nozzle 7 and the nozzle length H in Fig. 2, we found that when D/H≦0.25, the glass film thickness tends to be biased in the circumferential direction and the metal cannot be pulled up stably. It was difficult. Although it is possible to operate if D/H≧0.5, it is preferable to set D/H≧1. This relationship was almost the same in the case of plate-shaped slits. In addition, if the object to be cast is a cylinder, the relative deviation of the nozzle opening and the molten metal surface at rest should be considered for deviations in the circumferential direction of the glass coating, and for deviations in the longitudinal and width directions if the object to be cast is a plate. It is important to take the proper position, and it is necessary to adjust the nozzle opening plane so that it is parallel to the molten metal surface.

Further, it is desirable that the holding temperature of the molten metal be 5° C. or higher than its melting point. If the temperature is below 5°C, nozzle clogging and product shape cannot be controlled correctly.

Regarding the physical properties of the glass used in the present invention,
It is necessary to have appropriate deformation resistance near the solidification temperature of the metal, and a viscosity in the range of 10 3 to 10 6 poise is selected as a target.

Furthermore, the method of the present invention can also be used to produce thin wires or foil strips by placing a glass molding device at the nozzle outlet. Further, by continuously supplying molten glass and molten metal, continuous operation for a longer period of time is possible.

The above description has been made regarding the case where the specific gravity of the molten metal is greater than that of the molten slag, but if this relationship is reversed, the metal will accumulate at the top and the molten glass at the bottom in the container. In this case, the present invention can be applied by installing a nozzle so that the opening of the nozzle faces above the molten glass and discharging the molten material downward from this nozzle.

(Example) Embodiments of the present invention will be described based on FIGS. 1a to 1d.

FIG. 1a shows a container made of a refractory covered with a steel shell 8 for storing molten glass and molten metal, and an injection port 1 with a lid 11 on the top side of the container for introducing the molten glass and molten metal.
0 and a pressure regulating valve 3, and a nozzle holder for holding a nozzle 7, and directly above the nozzle are a cooling mist spray for cooling molten glass and molten metal, and a cooling mist spray for cooling molten glass and solidified glass. This device is equipped with a take-up roll that pulls the metal upward. glass and metal (5
, 5% silicon steel) is melted in a separate melting furnace, and then the lid 11 of the device is melted.
The solution is poured into the container through the injection port, and the temperature is maintained at a constant temperature by a heating device (not shown). Thereafter, the nozzle and the nozzle holder are lowered into the glass layer by a lifting device (not shown).

At this time, the nozzle opening is closed with a dummy par 15 as shown in FIG. 1b. After lowering the nozzle to the specified position on the glass layer (Fig. 1C), dummy par 1
5 (Figure 1d). During this process, the nozzle is positioned closer to the molten metal surface than during the steady operation shown in FIG. 3a, and the molten metal is pulled up at a slower rate. As pulling begins and the metal is pulled upwards, the forced cooling inside the nozzle is changed from air cooling to mist cooling, the pressure inside the furnace is increased by pressure regulating valve 3, and the nozzle position is raised to shift to steady operation. . The product is pulled upward by a take-up roll 13. During operation, the product thickness and solidification position are detected, and the furnace pressure and nozzle position are adjusted to obtain a product with a constant thickness.

(Effects of the Invention) As explained above, according to the present invention, since the metal is solidified in the glass molded body, it is possible to obtain a clean and smooth product with less oxidation on the surface, and it is also possible to obtain an ultra-thin and ultra-fine product. Products can be cast. The shape of the product can be easily changed by simply changing the shape of the nozzle.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is an explanatory diagram of a nozzle used in the present invention. FIG. 3 is a diagram illustrating discharge behavior from a container containing mercury, which has a high specific gravity, and glycerin, which has a high viscosity. 1... Container 2... Container lid 3...
Pressure adjustment valve 4... Discharge nozzle 5... Impulse pipe 6... Nozzle holder 7... Nozzle
8... Iron skin 9... Refractory 10
... Inlet 11 ... fi 12 ... Expansillon joint 13 ... Take-up roll 14 ... Cooling mist spray 15 ... Dummy bar Fig. 1 (b) (c) (d) Figure 2 Figure 3

Claims (1)

[Claims] 1. Holding molten glass and molten metal in a molten metal container,
The opening tip of a nozzle that guides the molten metal out of the container is immersed in the molten glass layer, and while the molten metal is discharged outside the container while being covered with molten glass, it is forcibly cooled immediately near the exit side of the nozzle. A method for continuous casting of molten metal, characterized by solidifying the molten metal.