JPH04100672A - Molten metal holding vessel - Google Patents

Abstract

PURPOSE:To obtain a molten metal holding vessel having excellent heat insulating characteristic, a little vol. reduction, long service life and little dangerous degree of molten metal leakage accident by making a permanent lining refractory layer in two-layer structure and disposing the specific thickness of heat insulating sheet layer between the two layers. CONSTITUTION:By disposing the heat insulating sheet 3b between the permanent lining two layers 5a, 5b, the permanent lining 5b at the iron shell side has no unfavorable influence of looseness of joint part by disposing the heat insulating sheet 3b. Further, the inside permanent lining layer 5a can be checked at the time of exchanging lining brick (one time for 1-2 months) and as necessary, the inside permanent lining layer 5a is partially dug out, to observe the condition of the heat insulating material sheet 3b. The thickness of heat insulating sheet layer is limited to 2-10mm.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a container for holding molten metal, such as a ladle.

<Prior art> In a container for holding molten metal, such as a ladle, a low
Application of int furnace materials is progressing.

For example, from waxite M (0.87% Si) to zirconite (ZrJ 60%, Sin, 4 layer%), and from zirconite to alumina negative (/VzO1!lo%, Si
By changing the material of the lining refractory to O□8%), the quality improvement effect is achieved by extending the life and preventing the melt@contamination caused by SiO□.

However, a problem with applying a low Sin□ type furnace material is that the temperature below the molten metal increases due to an increase in the thermal conductivity of the refractory. For this reason, it is desirable to use heat insulating materials.

Figure 2 shows the lining structure of a common ladle.

1a is the refractory lining of the side wall, and a cast zircon refractory material (Zr0□43%, Si0□52%) is generally used. In addition, 1b is the refractory lining of the flooring, and waxy stone bricks (85% SiO□) are often used. Here 2
It is a permanent refractory, generally made of waxy bricks, and is often lined with two layers to disperse the joints to prevent steel leakage.

Fig. 3 is an example in which insulating bricks 3a are installed in the container shown in Fig. 2. Conventionally, as shown in this figure, one layer of permanent tension is used, and insulating bricks are installed between the permanent tension and the steel shell. There are many cases where

In this case, the thickness of the insulating bricks 3a is generally 25 to 65 cm, and if this is used, the volume of the container will be reduced and the amount of molten metal will have to be destroyed. Conversely, if you try to maintain the amount of molten metal and reduce the volume of the refractory,
The lining refractory layer needs to be made thinner, which shortens the life of the container.

In addition, the insulating bricks placed between the permanent tension bricks and the steel skin are crushed due to their high porosity and low compressive strength, and also due to the thermal expansion of the lining and permanent tension (
(tissue destruction), permanent tension joints may loosen or break, increasing the risk of leakage.

<Problems to be Solved by the Invention> An object of the present invention is to propose a molten metal holding container that has excellent heat insulation properties, has little volume reduction, has a long life, and has a low risk of leakage.

Means for Solving the Problems> That is, the present invention provides a molten metal holding container consisting of, from the inside, a lining refractory layer, a permanent refractory layer, and an outer skin such as an iron shell, in which the permanent refractory layer is This is a molten metal holding container characterized by having a layered structure and having a heat insulating sheet layer of 2 to 1 (1++ mff) arranged between the layers.

<Function> In the present invention, when applying a heat insulating layer to suppress the temperature drop of molten metal, two permanent refractory layers are used, and a heat insulating sheet with a thickness of 2 to 10 mm is placed between the eyebrows. Since the thickness of the lining refractory layer remains the same, there is no restriction on the amount of hot water that can be received into the container, and since no insulating bricks are used, the structure of the insulating bricks will be destroyed, so the permanent tension will not change. Joints are less likely to loosen or break, and there is less risk of molten metal leaking.

Therefore, the life of the container is not particularly deteriorated, and can have a long life corresponding to the original refractory layer.

FIG. 1 is a cross-sectional view of a molten metal holding container having the structure of the present invention.

A case will be described in which the present invention is applied to a ladle that is a molten steel holding container. Here, as the lining refractories 1a and 1b, zircon casting materials and alumina furnace materials (AhOs 70% or more), which exhibit higher durability than pyrolithic bricks, are mainly used.

In general, lining bricks disappear due to erosion by molten metal or molten slag and are replaced after one to two months, but permanent lining bricks are replaced every year unless there are accidents such as leaks.

If a heat insulating sheet is installed between the permanent bricks and the lining bricks, it will melt away along with the lining at the end of the furnace life, and will need to be replaced every time, increasing costs. In addition, if it is installed between the permanent tension layer and the steel sheathing, the replacement cycle will be the same as that of the permanent tensioning layer, but even if tissue destruction of the insulation sheet occurs and joint breaks in the permanent tensioning layer on the steel sheathing side occur. Inspection during the process becomes impossible and there is a risk of hot water leakage.

On the other hand, by installing the heat insulation sheet 3b between the two permanent tension layers 5a and 5b as in the present invention, the installation of the heat insulation sheet 3b does not have any adverse effects such as loosening of the joints on the permanent tension 5b on the iron skin side. The inner permanent tension layer 5a can be inspected when the lining bricks are replaced (every 1 to 2 months), and if necessary, the inner permanent tension layer 5a can be partially removed and the insulation material notebook 3b It is possible to check the status of

The thickness of the heat insulating sheet layer is limited to 2 to 10 wrl.

If the thickness is less than 2 mm, it will not function adequately as a heat insulating material. If the thickness is more than 10 mm, the internal volume of the container will be significantly reduced, and the amount of hot water that can be received will be reduced.

A sheet-like insulation material is good. Unlike molded board-like products, which require multiple shapes, sheet-like products can be cut and stretched with just one shape, and can be used by stacking sheets. It is possible to set it to any thickness.

Specific materials constituting the heat insulating sheet include magnesia, graphite, mullite, etc., and mullite is preferable in the case of molten steel.

<Example> A heat insulating sheet was applied to a 255 ladle with the refractory lining configuration shown in FIG. The side wall lining is made of alumina poured material (/VzOi 78%, MgO 9%) at 180o.
n thickness, and the flooring is made of waxy brick (Si0□85%)
250in + I"l. The permanent cladding is made of waxy stone brick with two layers of 65mm thickness and 30mm thickness for the side walls and flooring.
The iron shell side was 65mm thick, and the lining side was 30mm thick. Two layers of mullite insulation sheets, 2 strokes thick, are placed between the permanent tension layers, and therefore a 4 mm thick layer is covered with alumina mortar (AI,
o, 64%).

When this ladle was used, an inspection at the time of replacing the lining bricks at 240 charges showed that there were no cracks in the inner permanent lining layer, and the 3-furnace charge (240 x 3 = 72
0 charge) After use, I replaced the 30 round permanent tension layer and the insulation notebook. At this time, the heat insulating sheet was partially deteriorated, but the 65 nn thick permanent tension on the back was in good condition, and it was possible to use it again for three furnaces.

In addition, as shown in Figure 4, the effects of installing insulation materials are as follows:
Compared to the case without insulation material, the difference in temperature drop rate between the end of degassing of low carbon aluminum quilt steel and the end of degassing is 0.1 ~
An effect of 0.2°C/lIn was obtained.

As a result, even if alumina-based pouring material is used as the lining brick, it can be used stably without increasing the temperature drop.

Although the above embodiment describes the application of the present invention to the ladle-1, it goes without saying that the present invention is applicable not only to ladles, but also to continuous casting tundishes and other molten metal containers in general.

<Effect of the invention> The present invention has the following effects.

(1) The temperature drop in the 7g melting metal container/8 hot water can be reduced, and it is possible to use high alumina refractories and basic refractories with low SiO□ high heat transfer coefficients as ladle consumable refractories.

(2) The internal volume of the container hardly decreases, and there is no restriction on the amount of hot water that can be received.

(3) There is no risk of leakage due to loose or broken joints in the outer permanent refractory layer.

(4) The life of the heat insulating sheet is long and the cost is low.

(5) The thickness of the heat insulating layer can be freely changed between 2 and 300 yen, and the heat insulating effect can be appropriately selected depending on the material of the consumable lining.

[Brief explanation of drawings]

Figure 1 is a sectional view of an embodiment of the present invention, Figure 2 is a conventional ladle lining structure, Figure 3 is a conventional ladle lining structure with a heat insulating sheet, and Figure 4 is molten steel temperature drop. It is a comparison chart of rates. Fig. 1 1a... Lining refractory (side wall), 1b... Lining refractory (padding), 2... Permanently lined refractory, 3a... Insulating brick, 3b... Insulating sheet, 4. ... Iron skin, 5a... Inner permanent tension layer, 5b... Outer permanent tension layer. Figure 2

Claims (1)

[Claims] In a molten metal holding container consisting of, from the inside, a lining refractory layer, a permanent refractory layer, and an outer skin such as an iron skin, the permanent refractory layer has a two-layer structure, and a heat insulating sheet layer with a thickness of 2 to 10 mm is provided between the layers. A molten metal holding container characterized by having: