JP2000061616A - Ladle for casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of a molten metal temp. in a ladle and to obtain the ladle having a structure of high durability by providing an alumina crucible disposed at the center part in the ladle main body and a peripheral gap for filling a carbonaceous material for heating formed between the ladle main body and the crucible, burning the carbonaceous material for heating an continuously heating the crucible till the time of using a molten metal from just before receiving the molten metal. SOLUTION: At the time of receiving a molten metal, a carbonaceous material 3 for heating is ignited and burnt with a burner 8 and the forcible blasting from a hose 11 is executed to heat a crucible 2 from the outer surface side. At the time of raising both inner and outer surfaces of the crucible 2 to near the received temp. of the molten metal, the high temp. molten metal 13 of cast iron, etc., is received. In this way, since the molten metal can be received without nearly generating the temp. difference between both inner and outer surfaces of the crucible 2, even in the case of using the crucible 2 of a material having low thermal conductivity such as the alumina, a crack caused by thermal shock is not generated an further, the heat of the molten metal is not driven off by the crucible 2 and the heat loss can be prevented. The temp. of the high temp. molten metal 13 when the combustion of the carbonaceous material 3 for heating is executed till the pouring time into a mold, can be lowered as much as the heat loss amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladle for castings, and more particularly to a ladle for castings, which is useful when applied to the use of handling high temperature molten metal such as cast iron in a foundry.

[0002]

2. Description of the Related Art A conventional ladle has a structure in which a refractory is lined on the inner surface of an outer shell iron shell in the form of a container, and the molten metal accommodated therein directly contacts the refractory lined. There are several types of refractory lining, and the structure and manufacturing method of the ladle differ depending on the materials used. Ladles with a structure in which the inner surface of the outer shell is lined with refractory bricks and ladle with a structure in which the inner surface of the outer shell is lined with castable refractory are typical.

[0003]

When the molten metal is put into the ladle, the lining refractory first loses heat, and further radiates heat over time, gradually lowering the molten metal temperature. For example, in the case of ductile cast iron that is subjected to molten metal treatment in a ladle, it is cast at 1450 to 1420 ° C. after the molten metal treatment, but the molten metal temperature when it is put into the ladle from the holding furnace occurs before use. Expecting a temperature drop, usually 1500 ° C
It is about. As described above, in the conventional structure, the temperature of the molten metal poured into the ladle must be several tens of degrees higher than the operating temperature, resulting in extremely large energy loss.

There is also a problem with the structure of the ladle, its manufacture and repair. In the case of a ladle with a structure in which the inner surface of the outer shell is lined with refractory bricks, the molten metal leaks if there is a gap in the joints (joints) of the bricks, so it is necessary to make the joint thickness as small as possible. Therefore, bricks are processed into different shapes and piled up and lined. This requires a long work by a skilled craftsman and increases the manufacturing cost.

In the case of a structure in which the inner surface of the outer shell iron lining is lined with castable refractory, a forming frame is arranged inside the outer shell iron wrap, and the gap between the two is filled with castable refractory. Work is done, but this work also requires a high level of skill. With this structure, it is difficult to form a dense inner lining layer with no gaps, and it takes time to dry the inner lining layer.

If the ladle is continuously used, the refractory lining may be melted or cracked. In this case, the repaired refractory such as clay mortar or plastic refractory will repair the damaged part, but this work is also extremely troublesome. If severely damaged and unrepairable, the refractory lining will be rebuilt. At that time, the old refractory lining is first disassembled and completely removed, but the work is extremely troublesome. The refractory lining may be sintered by contact with the molten metal, and the metal may infiltrate into the structure. Therefore, a dismantling machine such as a pick may not function, and dismantling of the refractory material requires a great deal of time and labor.

[0007] In order to solve the above-mentioned problems in manufacturing and repairing the ladle, the applicant of the present invention has previously proposed that the refractory portion of the lining that comes into contact with the molten metal be made of a crucible (Actual No. 7-43).
No. 33 publication). Although the crucible has high durability and is easy to replace, it can solve the above problems, but if the preheating of the crucible is insufficient, it may crack due to thermal shock, especially when used at high temperatures such as cast iron. It was found to be remarkable in the alumina crucible. A graphite crucible with high thermal shock resistance cannot be used because it reacts with cast iron.Therefore, an alumina crucible is used.However, an alumina crucible has a lower thermal conductivity than a graphite crucible and does not preheat. If it is sufficient, it is considered that a large temperature difference occurs between the inner surface side and the outer surface side of the crucible and, for example, when it receives a molten metal of 1500 ° C., it is likely to be cracked by thermal shock.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to prevent the temperature of the molten metal in the ladle from decreasing even in the case of high-temperature molten metal such as cast iron, and to manufacture and maintain it. It is to realize an easy and durable casting ladle structure.

[0009]

The present invention is directed to a ladle body,
A crucible installed in the central portion of the main body, and a heating carbon material filling circumferential gap formed between the ladle body and the crucible,
The present invention relates to a casting ladle characterized in that the crucible can be heated by burning the carbon material for heating filled in the circumferential gap.

Furthermore, the present invention is a ladle for castings, which is applied to the use of high-temperature molten metal such as cast iron, in which a ladle body, an alumina crucible installed in the center of the body, and a ladle. A heating carbon material-filling circumferential gap formed between the pot body and the crucible is provided, and by burning the heating carbon material filled in the circumferential gap, when the molten metal is used immediately before receiving the crucible. The present invention relates to a casting ladle characterized by being capable of being continuously heated up to.

Further, the present invention comprises a ladle body and a crucible installed in the center of the body, and the inside of the crucible is filled with ceramic balls which are heated immediately before receiving the hot water. The present invention relates to a casting ladle characterized in that it is floated on the surface of the molten metal due to the difference in specific gravity from the molten metal.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings. In all the drawings, the same reference numerals indicate substantially the same parts.

1 and 2 show an embodiment of the first invention of the present invention, which has a structure suitable for use in handling high-temperature molten metal such as cast iron. The casting ladle shown in the drawing is provided with a ladle body 1 and a crucible 2 installed in the center of the body 1, and around the crucible 2 there is a heating carbon material 3 between the ladle body 1 and the ladle body 1. A surrounding space 4 for filling is formed. Hereinafter, the configuration of each unit will be described in more detail.

The ladle body 1 is provided with an outer shell iron skin 1a and a refractory lining 1b, and the refractory lining 1b is made of refractory bricks or castable refractory as usual. The side of the ladle body 1 is provided with a hanging device for moving and carrying by applying a crane or the like, for example, a trunnion 5 (see FIG. 2).

The crucible 2 is provided in the ladle body 1 at a substantially central portion thereof.
It is installed with a clearance 4 between it and the refractory lining 1b.
As the crucible 2, an aluminous crucible that does not react with cast iron or the like is used because it is used for charging high-temperature molten metal such as cast iron. When applied to molten metals other than cast iron, graphite crucibles, mullite crucibles, zirconia crucibles, etc. can be used in addition to alumina.

The heating carbon material 3 is filled in the circumferential gap 4 between the lining refractory 1b of the ladle body 1 and the crucible 2. As the heating carbon material 3, various carbon-based solid fuels such as coke, charcoal and graphite can be used.

In order to ignite and burn the carbon material 3 charged in the circumferential gap 4, for example, the burner 8 can be detached from the ignition port 7 of the lid 6 provided on the ladle body 1 toward the inside of the circumferential gap 4. It is designed to be inserted and installed in. In order to ensure smooth combustion of the carbon material 3, a vent hole 9 is provided in the side wall of the ladle body 1 and an exhaust port 10 is provided in the lid 6. A hose 11 is detachably connected to the tip end port 9a of the ventilation hole 9, and combustion can be actively performed by forced ventilation from the hose 11.

To receive hot water, first, a burner 8 is applied to ignite and burn the heating carbon material 3 to heat the crucible 2 from the outer surface side, and by this heating, both the inner and outer surfaces of the crucible 2 rise to near the hot water temperature. After that, the hot metal 13 such as cast iron is received. By doing so, it is possible to receive the hot water with almost no temperature difference between the inner and outer surfaces of the crucible 2, and the crucible 2 is made of a material having low thermal conductivity such as alumina. Even when configured, the crucible 2 will not be cracked by thermal shock. Further, the heat is not taken by the crucible 2 when receiving the hot water, and the heat loss at the time of receiving the hot water can be prevented.

The combustion of the heating material 3 continues during the hot water reception and during the standby for transportation after the hot water reception, and during this time, the crucible 2 is continuously heated.
By this continuous heating, the heat dissipation loss after the hot water is received until the casting of the mold can be substantially eliminated.

By preventing the heat loss at the time of receiving the hot water and preventing the heat dissipation loss from the time after the hot water is received to the time of use, it is possible to prevent the temperature drop of the high temperature molten metal 13 from the time of receiving the hot water to the time of use. Therefore, the temperature of the high-temperature molten metal 13 at the time of receiving the hot water can be lowered by several tens of degrees as compared with the conventional case. For example, in the prior art, in consideration of the temperature drop from the time after hot water is received to the time of use, hot water is received at a temperature (for example, 1500 ° C.) several tens of degrees higher than the temperature during use (for example, 1450 to 1420 ° C.) According to the casting ladle of the present invention having the configuration, it is possible to receive the hot water at a temperature substantially close to the temperature at the time of use, and it is possible to lower the temperature by, for example, several tens of degrees, and reduce energy loss.

It is inconvenient if the hose 11 is attached when moving and transporting the ladle.
1 is removed, and air is taken in through the vent hole 9. A plurality of ventilation holes 9 are provided, and the ventilation holes 9 for forced ventilation are provided during forced ventilation.
Only the opening is opened, and the vent holes 9 other than the above are provided with plugs 12 so that they are opened during natural ventilation.

In the first aspect of the present invention, the carbon material for heating is charged in advance in the crucible 2 in addition to the outside of the crucible 2, and the carbon material is burned from the inside and the outside of the crucible 2. Inside the crucible 2,
You may make it heat from the outside. The carbon material in the crucible 2 may be burned by heat from the outside of the crucible 2, or may be burned by applying a burner installed inside the crucible 2.

FIG. 3 shows the latter type. The carbon material 3'containing the crucible 2 inside is ignited and burned by applying a burner 8'installed in the crucible 2, and the heat of combustion from the crucible 2 causes the crucible 2 to be burned. The carbon material 3 outside is ignited and burned.
The casting ladle of the type shown in FIG. 3 is provided with a rustle 14 and an ash outlet 15 for discharging the ash after combustion generated outside the crucible 2.

In the casting ladle of the type shown in FIG. 3, a high heating power can be easily obtained by the direct heating by the burner 8'and the burning of the carbon materials 3, 3'inside and outside the crucible 2 and the burner. After removing 8 ', until the hot water is received, the internal and external heating of the crucible 2 can be maintained, and the heat loss during the hot water reception can be prevented more reliably. By the way, after the hot water is received, the carbon material 3'in the crucible 2 and its combustion residue float on the surface of the molten metal due to the difference in specific gravity, so it can be removed by the slag removal work performed before pouring the molten metal into the mold or the like. . In the embodiment shown in FIG. 3, the carbon material 3 outside the crucible 2 may be omitted in some cases.

In the present invention, the carbon material 3 filled in the outer side of the crucible 2 may be ignited and burned by applying a burner 8'installed in the crucible 2 as shown in FIG. .

An embodiment of the second invention of the present invention is shown in FIG.
6 is shown. In the second invention, the crucible 2 is installed in the center of the ladle body 1 in contact with the lining refractory 1b, and in the crucible 2 near the tap 16 side.
A weir 17 is provided, a molten metal communication port 18 is formed below the lower end of the weir 17, and the tap hole 16 is connected to the inside of the crucible 2 through the communication port 18. Ceramic balls 19 are inserted in the crucible 2.

In the second aspect of the invention, the crucible 2 and the ceramic balls 19 are preheated to a temperature close to the hot water receiving temperature by applying a heating means such as a burner before the hot water is received, and then, as shown in FIG.
As shown in, the hot metal 13 is received.

The alumina refractory material forming the crucible 2 has a low thermal conductivity, and if it is directly exposed to the hot water, the temperature difference between the inner and outer surfaces becomes large, which may cause cracks due to thermal shock. The preheating of the can prevent the occurrence of cracks due to thermal shock. Further, if the hot water is received without preheating, the heat is taken by the crucible 2 and heat loss occurs. However, the above-mentioned preheating can prevent the heat loss at the time of receiving the hot water.

As shown in FIG. 6, after the hot water is received, the ceramic balls 19 float on the surface of the molten metal due to the difference in specific gravity and suppress the heat dissipation from the high temperature molten metal 13. Since the ceramic ball 19 floating on the surface of the molten metal is stopped by the weir 17,
Hot water can be discharged from 6 without any trouble. The ceramic ball 19 can be used repeatedly. Ball 19
As the ceramic constituting the above, any material that can float on the surface of the molten metal due to the difference in specific gravity may be used.For example, various ceramics used as refractory linings in the furnace, for example, alumina refractory, other silica, magnesia , Zirconia, etc. can be used.

In the second invention, as seen in the first invention, the crucible can be heated from the outside.

In the second invention, as in the first invention, it is possible to prevent the occurrence of cracks in the crucible which may occur when the hot water is received, and the temperature drop between the time when the high temperature molten metal is received and the time when the metal is used.

[0032]

According to the first and second aspects of the present invention, the following effects can be obtained.

(1) Since the ladle has a heating and holding function,
The molten metal temperature can be maintained for a long time.

(2) Since it is not necessary to expect a temperature drop,
For example, the molten metal in the melting furnace can be pulled down by several tens of degrees,
It saves energy.

(3) Since the part that directly contacts the molten metal is composed of a crucible, it is not necessary to apply refractory lining,
Liner work and drying work become extremely easy.

(4) Since only the heating of the crucible is required, the preheating time becomes extremely short. (5) The thermal shock resistance of the crucible is remarkably improved, and the durability is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment according to a first invention of the present invention.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is a vertical cross-sectional view showing another embodiment.

FIG. 4 is a vertical sectional view showing still another embodiment.

FIG. 5 is a vertical cross-sectional view showing an embodiment of the second invention of the present invention before receiving hot water.

FIG. 6 is a vertical sectional view of the same after receiving hot water.

[Explanation of symbols]

1 ladle body 2 crucible 3 Carbon material for heating 4 laps 5 trunnion 6 lid 7 Ignition mouth 8 burners 9 vents 10 exhaust port 11 hose 12 stoppers 13 High temperature molten metal 14 Lostor 15 Ash outlet 16 Outlet 17 weir 18 Contact 19 ceramic balls

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuyuki Shirakawa             3-11-32 Inadashinmachi, Higashiosaka City, Osaka Prefecture             Nippon Crucible Co., Ltd. F-term (reference) 4E014 AA02 DC01

Claims (7)

[Claims] 1. A ladle body, a crucible installed in a central portion of the body, and a heating carbon material filling gap formed between the ladle body and the crucible. A ladle for casting, characterized in that the crucible can be heated by burning a carbon material for heating filled therein. 2. The casting ladle according to claim 1, wherein the casting ladle is used for handling high-temperature molten metal such as cast iron, and an alumina crucible is used as the crucible. 3. A ladle body is filled with a heating carbon material, and the carbon material is ignited and burned so that the crucible can be heated from the inside and the outside immediately before receiving the hot water. The casting ladle according to Item 1 or 2. 4. The casting according to any one of claims 1 to 3, further comprising: a vent for taking in combustion air, an outlet for combustion gas, and a means for igniting a carbon material for heating. Ladle. 5. A ladle main body and a crucible installed in the center of the main body, wherein the crucible is filled with ceramic balls to be heated immediately before receiving the hot water. A ladle for castings, characterized in that it floats on the surface of the molten metal due to the difference in specific gravity between 6. A crucible is provided with a spout and a weir near the spout, and the weir prevents the aluminum balls from moving to the spout at the spout. The ladle for casting according to claim 5. 7. The casting ladle according to claim 5, wherein the crucible can be heated from the outside.