JPH05337635A - Molten metal holding vessel - Google Patents

Abstract

PURPOSE:To provide a molten metal holding vessel in which the clogging of a molten metal passage caused by solidified metal is prevented and the discharge of molten metal from the molten metal passage can be made to be excellent and the use of filling material contaminating the molten metal can be abolished. CONSTITUTION:This vessel is constituted of a vessel body 1 with bottom having the holding chamber 12 for holding the molten metal, a cylindrical exothermic body 2 forming the molten metal passage 20 for discharging the molten metal by inner wall surface 2a and a carbonaceous electrode part 3 fitted to the outside of the exothermic body 2 and supplying electric power in the exothermic body 2. The exothermic body 2 is constituted with the mixed body of magnesia, zirconia and alumina. The exothermic body 2 and the electrode part 3 are embedded into a refractory layer 11 in the vessel body 1 and electrically insulated. The electric power is supplied to the exothermic body 2 through the electrode part 3, thereby the exothermic body 2 is energized to heat the metal in the molten metal passage 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal holding container. This molten metal holding container can be used as, for example, a ladle holding molten steel.

[0002]

2. Description of the Related Art A molten metal holding container, such as a ladle, has a holding chamber for holding molten metal and a tapping passage provided at the bottom. Here, since the temperature becomes low in the vicinity of the tap passage, the molten metal may solidify near the tap passage. In this case, there is a problem that the hot water discharge passage is clogged and opening of the hot water discharge passage becomes difficult, and hot water cannot be discharged.

In order to prevent this, it has been practiced to previously fill the tapping passage with a powdery or granular filler material (such as sand sand, chrome iron ore, or a carbon coating material thereof). Then, at the time of tapping, the opening / closing plate of the tapping passage is opened, and the molten metal in the holding chamber is dropped from the tapping passage together with the filler in the tapping passage. However, in this case, the filler filled in the tap passage may often be sintered by heat. In this case, even if the opening / closing plate is opened, the molten metal cannot be discharged. Further, the molten metal discharged from the tapping passage is contaminated with the filler, which is not preferable in terms of cleaning the molten metal and improving its quality.

[0004]

SUMMARY OF THE INVENTION The present invention was developed in view of the above-mentioned circumstances, and it is possible to prevent clogging of a hot water discharge passage due to solidified metal and to improve hot water discharge from the hot water discharge passage.
It is another object of the present invention to provide a metal melt holding container capable of eliminating the use of a filler that contaminates the melt.

[0005]

A container for holding molten metal of the present invention is equipped with a bottomed container body having a holding chamber for holding the molten metal, and the container body is equipped with the molten metal in the holding chamber outside the holding chamber. It is characterized in that the hot water discharge passage is formed by an inner wall surface and is composed of a cylindrical heating element that generates heat with power supply and at least two electrode portions that supply power to the heating element.

The container body has a bottomed shape and has a holding chamber for holding the molten metal. The heating element is mounted on the container body, and its inner wall surface forms a hot water outlet passage. The heating element can be formed mainly of conductive ceramics. When the molten metal held in the holding chamber is molten steel, the heating element is generally magnesia (MgO), zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), or a mixture of magnesia and zirconia. Body, a mixture of magnesia, zirconia and alumina. Although magnesia is an electrically insulating material in the normal temperature range, it has conductivity near 1500 ° C., which is near the melting point of steel, and a required specific resistance value can be obtained.

Here, when a mixture of magnesia, zirconia and alumina is used as the ceramic forming the heating element, alumina is effective for controlling the resistance value of the heating element, and zirconia is the heating element. It is effective in improving the heat resistance, impact resistance, and hot characteristics of the steel, and is also effective in controlling the resistance value. In this case, considering the thermal shock resistance, thermal expansion property, specific resistance value, etc., the mixing ratio is, for example, by weight, magnesia is preferably 60 to 99%, particularly preferably 85 to 95%, and zirconia is 1 to 1. 40%. Especially 5 to 2.5%
Is preferred, 1-40% alumina, especially 2.5-15
% Is preferred.

In the case of holding molten steel, the specific resistance value of the heating element is preferably 20 Ωcm or more at about 1500 ° C., and particularly preferably 200 Ωcm or more. Note that the particle size of the ceramics forming the heating element may affect the resistance value and the uneven distribution of current, so the maximum particle size of the ceramic powder is preferably about 0.5 mm to 5 mm, and particularly about 0.7 mm to 3 mm. Is desirable.

The electrode portion is for supplying power to the heating element. The material of the electrode portion is selected in consideration of conductivity, heat transfer coefficient, etc., and, for example, carbon paper, solid alumina graphite-based material, or porous carbon-based refractory can be adopted. The arrangement, shape, and strength of the electrode parts are preferably such that the influence of thermal expansion of the heating element can be avoided. In order to absorb the thermal expansion of the heating element, it is preferable that the electrode part has a low compressive strength.

[0010]

When the heating element is supplied with electricity through the electrode portion to generate heat, the metal in the tap passage is heated and solidification of the molten metal in the tap passage is avoided.

[0011]

EXAMPLE An example of the molten metal holding container according to the present invention will be described with reference to FIGS. This example is applied to a ladle capable of holding about 300 kg of molten steel. FIG. 1 shows the main part of the molten metal holding container according to this embodiment.
Shown in. This holding container includes a container body 1 having a bottomed shape, a nozzle-shaped heating element 2, and a carbon-based electrode portion 3 that supplies power to the heating element 2.

The container body 1 comprises a steel iron shell 10 having an opening 10a in the bottom wall, a refractory layer 11 of a required thickness lined on the inner wall surface of the iron shell 10, heat insulation and the iron shell 10. It is composed of a backing material 15 made of low stone brick for protection and a mass brick 14 embedded in the refractory layer 11. The refractory layer 11 contains magnesia carbon as a main component, and the thickness thereof is about 100 to 150 mm. The refractory layer 11 forms a holding chamber 12 that holds the molten metal. Trout brick 14
Is mainly composed of magnesia carbon, and is provided for mounting the nozzle type heating element 2. A slide-type opening / closing plate 13 is provided below the opening 10 a of the container body 1.

The heating element 2 is mounted in the mass brick 14 near the opening 10a. A hot water outlet passage 20 is formed on the inner wall surface 2 a of the heating element 2. The heating element 2 is made of mixed ceramics containing 90% of magnesia, 5% of zirconia, 5% of alumina, and inevitable impurities in weight%. Here, in this embodiment, the heating element 2 has an axial length of 120 m.
m, outer diameter is 70 mm, and inner diameter is 30 mm.

The heating element 2 was manufactured as follows. That is, the raw material is crushed by a roll crusher, an impeller breaker or the like to obtain coarse or medium particles, and further finely pulverized by a ball mill, a vibration mill or the like to obtain a fine particle material, and each is blended and mixed so as to obtain an appropriate particle size constitution, An adjusting step of adding water to the powder to form a slurry, a molding step of pouring the slurry into a cavity of a mold for molding, a drying step of curing and drying the molded body after the molded body is removed from the mold, and a dried molded body. This was manufactured by sequentially performing a sintering step of sintering.

The electrode portions 3 are mounted on the outer peripheral surface of the heating element 2 so as to face each other. The electrode unit 3 is connected to a single-phase power source 4 arranged outside the container via a power supply line 3a. The electrode portion 3 and the power supply line 3a are embedded in the refractory layer 11 to ensure electrical insulation. In addition, the power supply line 3a
In order to improve the electric insulation of the above, the ceramic pipe having the feed line 3a inserted therein may be embedded in the refractory layer 11.

Next, the case of use will be described. With the open / close plate 13 closed, high temperature (1
The molten metal of 550 to 1600 ° C, that is, molten steel is held. In this state, power is supplied from the single-phase power source 4 to the heating element 2 via the power supply line 3a and the electrode portion 3. In this case, generally, the voltage is about 200 to 400 V and the current is 200 to 80 V.
Set to about 0A. As a result, the heating element 2 is
Even if the molten metal in 0 is solidified, the heating element 2 generates heat and heats the molten metal to an appropriate temperature to melt the molten metal. Therefore, heat generation is started, and after the time required for melting has elapsed, the opening / closing plate 1
By opening 3, the molten metal can be discharged smoothly. If the heating element 2 is made to generate heat until the discharge of the molten metal is completed, the temperature drop of the molten metal can be prevented.

Before holding the molten metal in the holding chamber 12,
If the heating element 2 is energized and preheated, the heating element 2 can be prevented from being rapidly heated due to contact with the molten metal, and the heating element 2 caused by the rapid heating can be prevented.
It is advantageous to prevent cracking of the. Further, by the above-mentioned preheating, it is possible to secure the conductivity of the heating element 2 which has magnesia as a main component and has conductivity in a high temperature region. As described above, in the present embodiment, the heating element 2 can heat the metal in the hot water outlet passage 20, so that clogging of the hot water outlet passage 20 can be prevented.
Therefore, the filler used conventionally can be eliminated.

(Other Example) In the above embodiment, when the molten metal in the holding chamber 12 is discharged from the tapping passage 20, an inert gas or oxygen gas is bubbled through the tapping passage 20 to open the opening of the tapping passage 20. You may try to help. Further, in the above-described embodiment, granular pig iron (melting point: 1200 ° C.) is packed in the tap passage 20 of the heating element 2 before the molten metal is held in the holding chamber 12, and then the holding chamber 12 is held.
Alternatively, the molten metal may be held in place, and the hot metal 2 may heat and melt the granular pig iron immediately before tapping to open the tapping passage 20. Since the melting point of granular pig iron is lower than that of steel, the tap water passage 20
It is possible to suppress heat generation of the heating element 2 at the time of opening.

In the above embodiment, the hot water outlet passage 2
Since the temperature in the lower part of 0 is lower than the melting point of aluminum, a mixed powder of iron oxide and aluminum powder is packed in the lower part of the hot water passage 20 of the heating element 2 in advance to generate heat in the heating element 2 and the thermite. The heat generated by the reaction may also be used to heat and melt the metal in the tap water passage 20. A second embodiment of the present invention is shown in FIGS. In this case, a pair of electrodes 3 and a pair of electrodes 5 are used, and the electrodes 3 are mounted on the outer peripheral surface of the heating element 2 so as to face each other, and The heating element 2 is equipped so that the outer peripheral surface of the heating element 2 is offset from each other and faces each other. Then, the pair of two electrode parts 3 is connected to the single-phase power source 4 via the power supply line 3a, and the remaining two
The pair of electrode portions 5 are connected to the single-phase power source 6 via the power supply line 5a. In this example, it is advantageous to heat the entire heating element 2.

A third embodiment of the present invention is shown in FIGS.
In this case, a set of three electrode parts 3 is used, and each electrode part 3
Are provided on the outer peripheral surface of the heating element 2 at substantially equal intervals. And each electrode part 3 is connected to the three-phase power source 4 via the power supply line 3a. In this example, it is advantageous to heat the entire heating element 2. A fourth embodiment of the present invention is shown in FIGS. In this case, a cylindrical electrode portion 60 is arranged on the outer peripheral surface of the heating element 2, and a rod-shaped electrode portion 61 is arranged inside the tap passage 20 of the heating element 2. Then, the electrode parts 60, 61 are connected to the single-phase power source 4 via the power supply line 3a. In this example, since the electrode portion 60 is arranged around the entire circumference of the heating element 2, the heating element 2
It is advantageous for the overall heating of.

A fifth embodiment of the present invention is shown in FIG. In this case, the electrode portion 70 is arranged on the outer peripheral surface of the upper portion of the heating element 2, the electrode portion 71 is arranged on the outer peripheral surface of the center of the heating element 2, and the electrode portion 72 is arranged on the outer peripheral surface of the lower portion of the heating element 2. It is arranged. Then, the electrode unit 70 is connected to the single-phase power source 40 via the power supply line 70a.
, The electrode part 71 is connected to the single-phase power supply 41 via the power supply line 71a, and the electrode part 72 is connected to the single-phase power supply 42 via the power supply line 72a. In this example, the heat generation of the upper part, the center, and the lower part of the heating element 2 can be adjusted independently. For example, if power supply is started in the order of the electrodes 70, 71, 72, heat can be generated in the order of the upper part, the center, and the lower part of the heating element 2. In this case, since the solidified metal in the tap water passage 20 can be heated and melted sequentially from the upper portion thereof, cracking of the heating element 2 due to thermal expansion of the solidified metal in the tap water passage 20 can be avoided.

The sixth embodiment of the present invention is shown in FIG. In this case, a conductive layer 80 formed by loading carbon powder or the like is interposed between the heating element 2 and the electrode portion 3. The conductive layer 80 serves to secure electrical contact and thermal contact between the heating element 2 and the electrode portion 3. As the carbon powder, for example, one having an average particle size of 40 μm to 60 μm can be adopted.
A seventh embodiment of the present invention is shown in FIG. In this case, the heating element 2 is composed of a cylindrical outer layer 25 and a cylindrical inner layer 26,
A conductive layer 80 is interposed between the outer layer 25 and the inner layer 26 to improve electrical contact properties and thermal contact properties. In the case of this example, the material and composition of the outer layer 25 and the inner layer 26 can be different. For example, the materials and compositions of the outer layer 25 and the inner layer 26 can be adjusted so that the inner layer 26, which comes into direct contact with the molten metal, has higher heat generation properties, erosion resistance, etc. than the outer layer 25.

[0023]

According to the metal melt holding container of the present invention, the metal in the tap passage can be heated by the heating element, so that clogging of the tap passage due to solidified metal can be prevented and tapping from the tap passage can be improved. .. Further, by heating until the completion of tapping, it is possible to prevent the temperature of the molten metal during tapping from decreasing.

Therefore, it is possible to eliminate the use of conventional fillers that may contaminate the molten metal, which is advantageous for cleaning the molten metal and improving its quality.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a molten metal holding container.

FIG. 2 is a vertical cross-sectional view schematically showing a heating element provided with an electrode portion.

FIG. 3 is a cross-sectional view schematically showing a heating element provided with an electrode portion.

FIG. 4 is a vertical cross-sectional view according to a second embodiment schematically showing a heating element having an electrode portion.

FIG. 5 is a transverse cross-sectional view according to a second embodiment schematically showing a heating element having an electrode portion.

FIG. 6 is a vertical sectional view according to a third embodiment, which schematically shows a heating element having an electrode portion.

FIG. 7 is a transverse cross-sectional view according to a third embodiment schematically showing a heating element having an electrode portion.

FIG. 8 is a vertical cross-sectional view according to a fourth embodiment that schematically shows a heating element having an electrode portion.

FIG. 9 is a transverse cross-sectional view according to a fourth example schematically showing a heating element having an electrode portion.

FIG. 10 is a vertical cross-sectional view according to a fifth embodiment schematically showing a heating element having an electrode portion.

FIG. 11 is a vertical cross-sectional view according to a sixth embodiment schematically showing a heating element having an electrode portion.

FIG. 12 is a vertical cross-sectional view of a seventh embodiment schematically showing a heating element having an electrode portion.

[Explanation of symbols]

In the figure, 1 is a container body, 2 is a heating element, 20 is a hot water outlet passage, 3
Indicates an electrode part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eizo Kojima 4-11 Koya no Waki, Kagiya Town, Tokai City, Aichi Prefecture

Claims (1)

[Claims] 1. A bottomed container body having a holding chamber for holding molten metal, and a tapping passage provided in the container body for discharging the molten metal of the holding chamber to the outside of the holding chamber is formed by an inner wall surface. A molten metal holding container comprising a cylindrical heating element that generates heat with power supply and at least two electrode portions that supply power to the heating element.