JPS58154446A - Continuous casting method of steel and vessel for molten metal for said method - Google Patents

Abstract

PURPOSE:To enable the production of an alloy casting ingot having a specified compsn. in the stage of casting molten metal added with alloy components of high specific gravity continuously by increasing the height of a nozzle inlet in the bottom of a vessel for casting the molten steel into a casting mold so as to prevent the down flow of the molten metal having a high concn. of alloys of specific gravity from the nozzle. CONSTITUTION:Molten steel added with metals for alloys having large specific gravity such as Pb and Bi are charged from a ladle 1 into a tundish 2, and further said molten steel is cast through an immersion nozzle into a mold 4 for continuous casting. The inlet brick 32 of the nozzle 3 on the tundish 2 in this case is disposed in the position higher than the bottom surface 21 of the tundish 2. Or a gate 26 is provided between the position where the molten steel falls into the tundish 2 from the ladle 1 and the inlet of the nozzle 3. The molten metal of high specific gravity contg. much metals of high specific gravity such as Pb or the like is stopped in the position below the inlet of the nozzle 3, and only the molten metal of the specified compsn. is supplied from the nozzle 3 into the mold 4, whereby the production of a continuous casting product 15 contg. the compsn. that do not meet the requirements is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in continuous casting methods. The invention also relates to a molten metal vessel for use in carrying out the method.

For example, in the production of lead free-cutting steel, a predetermined amount of Pl) may be added to molten steel, which has been melted, refined, and other components have been adjusted, and then cast. However, Pb has a high specific gravity < ( ]], 34), and a portion of the added material sinks to the bottom of the ladle in a molten state, creating a molten layer that is mostly composed of Pb or at least contains a high concentration of Pb. There is a tendency to form.

When the nozzle at the bottom of the ladle is opened at °C and the molten metal is poured out using a lever, the molten metal containing a high concentration of Pb continues to be used for a while along with the molten metal of a predetermined composition. , the molten metal will have a composition that does not meet the specifications.

When steel is cast into bars by continuous casting, slabs with non-standard compositions are produced over a considerable length for the reasons mentioned above. Kneading, of course, lowers the product yield and is therefore not desirable.

This problem is not limited to pb, but is common when adding high specific gravity elements such as [31 (specific gravity 978).

The object of the present invention is to solve this problem and to realize continuous casting in which slabs meeting standard values can be obtained from the beginning of casting.

The continuous casting method for steel of the present invention achieves this objective by continuously casting steel to which high specific gravity alloy components are added. It is characterized by supplying the molten metal to the mold while preventing the molten metal from reaching the nozzle for pouring out the molten metal from the container.

In addition, the equipment used to carry out the above method, that is, the molten metal container for continuous casting of steel to which high specific gravity alloy components are added, is the part of the molten metal poured into the container that contains a high concentration of high specific gravity alloy components. Fix it at the bottom of the container, and then close the container. It is characterized by the provision of a weir means to prevent molten metal from reaching the nozzle. .

The term "molten metal vessel" as used herein refers to all vessels used while feeding the molten steel in the furnace to the mort, including both ladle and tumbler.

A typical embodiment of the continuous casting method of the present invention will be described with reference to the drawings. As shown in FIG.
The molten metal lO to which b has been added is poured into the tundish 2,
Therefore, the part 1 which contains a high concentration of PI) is a layer that has sunk to the bottom 21 of the tandish as shown by the thick arrow, and is blocked by the side wall of the nozzle brick 32 which is installed one step higher than the bottom, and the opening 31 of the immersion nozzle 3 is On the other hand, the molten steel 12 having a predetermined composition is supplied to the mold 4 through the immersion nozzle 3 as indicated by the thin arrow, and forms the slab 15.

As a weir means to prevent components that contain a high concentration of substances such as - In addition to providing the -L surface of (c) higher than the bottom surface of the tundish by an appropriate distance, various other embodiments are possible.

For example, in the existing tongue tissue, an overflow weir of an appropriate height is installed between the molten metal outlet (220 locations indicated by dotted lines in Figure 2) and the immersion nozzle, so that only molten steel of a predetermined composition is allowed to flow. It is sufficient to extend beyond this to reach the immersion nozzle.

If the opening of the nozzle is to be higher than the bottom of the molten metal container, the nozzle brick should not only be installed at a height (see Fig. 3 A and B).
As shown in FIG. 2, the surrounding portion 23 can also be made higher. Of course, the molten metal is dropped into the lower part 22.
The example shown in Figure 3 is a case where this method is applied to a ladle, but it goes without saying that it would be difficult to apply the same method to a tandish.On the contrary, the example shown in Figures 1 and 2 Naturally, the embodiment can also be applied to a ladle.

Alternatively, as shown in FIGS. 4A and 4B, the nozzle opening may be provided high on the bottom of the ladle, and a slope 24 may be provided that becomes lower from there toward the other portion 22.

[Brief explanation of drawings]

FIG. 1 is a sectional view centered on a tundish, showing continuous casting of steel by the method of the present invention. FIG. 2 is a plan view of the tundish of FIG. 1. FIG. 3 shows an example in which the present invention is applied to a ladle, in which A is a sectional view and B is a plan view. FIG. 4 shows another example in which the present invention is applied to a ladle, in which A is a sectional view and B is a plan view. 1 and Libe 2-1... Tan tissue 21... - bottom 25 Weir means 3 Immersion nozzle 11... Molten metal 12 containing a large amount of Pl)
Patent applicant for molten steel with a prescribed composition Daido Steel Co., Ltd. Agent Patent attorney Sou Suga 3 B 4 B Z4 (Z':))

Claims (6)

[Claims] (1) In a method of continuously casting steel to which high specific gravity alloy components have been added, the part of the molten metal that contains a high concentration of high specific gravity alloy components is kept at the bottom of the molten metal container, and the part of the molten metal that contains the high specific gravity alloy component is kept at the bottom of the molten metal container, and then placed in a nozzle that pours out the molten metal from the container. A method characterized by supplying molten metal to a mold while preventing the melt from reaching the mold. (2) The continuous casting method according to claim 1, wherein the high specific gravity alloy component is Pb or Bi, which has a low melt viscosity. (3) A molten metal container for continuous casting of steel to which high specific gravity alloy components have been added, in which the portion of the molten metal poured into the container that contains a high concentration of high specific gravity alloy components is fixed at the bottom of the container. A container characterized by being provided with a weir means for preventing molten metal from flowing from the container to a nozzle for pouring it out. (4) The container according to claim 3, wherein the molten metal container is a tongue tissue, and an overflow weir (C) is provided between the molten metal drop opening of the tongue tissue and the opening of the immersion nozzle as a weir means. (5) The container according to claim 3, wherein the molten metal container is a casing or a ladle, and a nozzle brick or nozzle brick and surrounding bricks are provided higher than the bottom surface of the container as a weir means. (6) The container according to claim 3, wherein the molten metal container is a ladle, and the bottom surface is provided with an inclined surface that becomes lower from the nozzle opening or the vicinity thereof toward other parts as a weir means.