JPH0791840A - Water-cooled ladle cover of ladle for refining metal - Google Patents

Abstract

PURPOSE:To improve a water cooling effect while preventing excess heat removal of cooling water by positively utilizing splash adhered to a water-cooled ladle cover by scattering as a heat insulator. CONSTITUTION:A water-cooled ladle cover 10 has a cooling passage 11 for guiding water to an inner surface side opposed to an inner space of a ladle 6. The cover 10 has a divided structure in which the cover 10 is laterally cut in section to at least an upper part and a lower part into thin round slices, which are integrally coupled by removable coupling means 14. The passage 11 is also similarly partitioned corresponding to the cover parts to form independent passages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to hot metal and molten steel under reduced pressure,
The present invention relates to a ladle lid having a water-cooling structure which is provided in a refining device for refining molten metal such as various other alloys, or a metal refining ladle used in a metal melting and refining device, etc.

[0002]

2. Description of the Related Art In a refining device or a metal melting and refining device for refining molten metal of ordinary steel, special steel, stainless steel, and molten steel, and alloys such as nickel alloys and chrome alloys under vacuum or reduced pressure. Is, for example, a metal refining ladle (hereinafter sometimes simply referred to as a ladle) in which the molten metal is injected and held in advance is installed at a predetermined position in the vacuum container, and then the decompression device outside the vacuum container is installed. To depressurize the inside of the vacuum vessel, and remove the molten metal held inside the ladle from the bottom of the ladle by introducing an inert gas such as argon gas supplied from the gas supply device outside the vacuum vessel. Oxygen gas is blown into the molten metal from the oxygen top blowing lance that can be moved up and down through the vacuum container and the ladle lid of the ladle while being stirred by being blown through the gas blowing nozzle provided in Refining is carried out, such as blowing Shi blow over.

Such an apparatus is capable of preferentially advancing the decarburization reaction to produce ultra-low carbon steel and alloys, degassing unnecessary gas in the molten metal, stirring the molten metal, and melting the molten metal. In recent years, many have been installed and used in order to effectively increase the amount and adjust the component composition.

In a refining apparatus for refining molten metal of this kind under reduced pressure, a ladle for refining metal is often used, and in particular, it is placed on a circular opening edge of the ladle so as to be openable and closable inside the ladle. The ladle lid that encloses the molten metal as much as possible is an indispensable member. This is because it is necessary for the following reasons.

There are cases in which the molten metal in the ladle has slag (layer) and cases in which it does not, but refining with the required metallurgical reactions under suitable temperature control by suppressing the temperature drop of this molten metal. In order to save energy especially when expensive electric energy is used as a heat source, the molten metal in the ladle etc. The radiant heat radiated from the inside to the inner wall of the vacuum container and the seal is blocked, and the vacuum container is made highly airtight.
In order to extend the service life of the vacuum vessel and its decompression equipment, maintain light maintenance, and reduce the power required for the decompression equipment, the ladle outside the ladle due to bumping of the molten metal that occurs when the pressure inside the vacuum vessel is reduced In other words, in order to prevent the molten metal from flowing out into the vacuum container, bumping of the molten metal described in the above section, stirring of the molten metal by ladle bottom blowing of inert gas, and blowing of oxygen gas from the oxygen top blowing lance In order to prevent splashes caused by and from scattering and adhering to the circular opening edge of the ladle itself, the outer pig skin, and the inner wall and seal of the vacuum container outside the ladle, In order to reduce the cleaning and repair work for the inside of the vacuum container and the seal portion, and to prevent the production yield of the refined molten metal from decreasing due to the above and items.

Conventionally, in a ladle used for refining a molten metal under such a reduced pressure, a ladle lid which is openably and closably mounted on the circular opening edge of the ladle is, for example, Japanese Patent Laid-Open Publication No. 56-146753, JP-A-2-205619
As disclosed in US Pat. No. 5,967,839, a refractory structure having a refractory arranged along the inside of a steel frame and an iron skin forming a skeleton and an outer shell has been used. This ladle lid is
For example, since it is placed directly above the ladle that holds a large amount of molten metal at a very high temperature of 1700 ° C or higher, it is normally not used to ensure safety at the operation site and improve operability and workability. The cooling type was used, and it had the following problems.

(A) Under severe conditions of use, the refractory structure is easily deformed, and the refractory is worn, damaged, and easily dropped from this structure.

(B) For the reasons described above and paragraphs,
The molten metal spillage and splash adhere to the ladle lid and enlarge it, making it impossible to place or repeatedly use.

(C) Splash is adhered to the opening for raising and lowering the oxygen top blowing lance of oxygen gas, which is provided in advance in the refractory structure, the insertion port of the hopper duct for supplying iron alloy, etc., and the gas vent port. As it enlarges, it blocks each of these openings, making it difficult or impossible to operate.

(D) Due to the reasons (a) to (c) above, frequent inspections, repairs and repairs must be performed.

(E) Due to the reasons (a) and (d) above, the useful life of the ladle lid is shortened (for example, 100
It is uneconomical because it increases the service life of heat) and cost.

Therefore, recently, such a ladle lid has a refractory structure (body) having various problems described in the above items (a) to (e), and is referred to the above item (c). Water cooling pipes (steel pipes) for passing cooling water through the ladle lid are attached in a concentric or zigzag spiral shape, except for the openings provided in the ladle lid in advance. A water-cooled structure in which the whole structure is wound in a state of being wound into a hat shape has been tried.

[0013]

This ladle lid having a water cooling structure generally achieves the original functions (roles and purposes) of the ladle lid described in the above items 1 to 3, and the above (a) to (e). )
The problems of the conventional refractory structure described in Section 1 are solved and the service life is extended, which is advantageous in terms of refining operation, workability, maintenance, cost, etc. Since the energy loss carried away from the molten metal inside the ladle due to the heat removal effect of the cooling water to be watered increases, as described in the above paragraphs and paragraphs, while suppressing the temperature drop of the molten metal and slag to save energy, above all It is disadvantageous and problematic in terms of refining and producing good quality molten metal under suitable temperature control.

That is, the energy corresponding to this energy loss has to be supplemented by appropriate means separately,
For this reason, the cost is increased and the operation and working conditions are changed, the operation and working time are extended, and the advantage of water cooling is not fully utilized.

Therefore, in order to solve the disadvantageous problems of the water-cooled ladle lid and to utilize the various advantages obtained by cooling with water, the inside of the ladle lid of the water-cooled structure is utilized. The splash layer (heat insulating layer) is positively used to form the splash layer (heat insulating layer) on the inner surface facing the space, which splashes from the molten metal and slag inside the ladle. It has been tried to suppress the heat removal action of the cooling water by the action to eliminate such a disadvantage. However, it is difficult to form the splash layer formed on the inner surface side of the ladle lid having such a water-cooled structure in a desired suitable shape and position. When this splash layer is abnormally grown and formed beyond the preferable state, it has various problems similar to those of the conventional refractory structure described in the above (b) to (e). is there. Whether it is a water-cooled ladle lid with a splash layer formed in a suitable state or a water-cooled ladle lid with an abnormally grown and formed splash layer, in any case, remove the water-cooled ladle lid from the ladle, and The operation is performed while replacing the water cooling ladle lid by repeating maintenance such as removing the splash layer from the water cooling ladle lid, but there are various problems in the removal and the replacement accompanied by maintenance.

Therefore, an object of the present invention is a water-cooling ladle lid having a water-cooling structure that positively utilizes the attachment of splashes splashing as described above, and forms a splash layer around the water-cooling pipe to perform a heat insulating action. The ladle lid described in the above items 1 to 4 can be efficiently and reliably performed in a desired and desired state, and the water cooling effect is suitably enhanced while preventing excessive heat removal by cooling water. In addition to solving the problems of the conventional refractory structure described in (a) to (e) above, the water-cooled ladle lid having a splash layer formed by abnormal growth is formed. It is an object of the present invention to provide a water-cooled ladle lid of a ladle which is convenient for replacement and which is totally satisfactory.

[0017]

SUMMARY OF THE INVENTION The present invention is a cooling passage which is openably and closably mounted on a circular opening edge of a ladle used for metal refining and which guides cooling water to an inner surface side facing the ladle internal space. In the water-cooled ladle lid provided with, the water-cooled ladle lid is formed into a split structure that is divided into at least two parts, an upper portion and a lower portion, in a sliced shape, and is removably integrally coupled. Is provided on the joint surface portion, while the cooling passage is formed as an independent passage corresponding to each of the divided lid portions, a water cooling ladle lid for a metal refining ladle.

Further, according to the present invention, the cooling passage is formed in a hat shape by a water cooling pipe wound so as to be installed as much as possible, and is connected in series in the horizontal direction of the lowermost stage which abuts on the circular opening edge of the ladle. The water-cooling pipe located on the central axis side within the circular opening of the ladle of the water-cooling pipe group that is disposed protrudes in the central axis direction beyond the radius of the water-cooling pipe with respect to the water-cooling pipe immediately above it. It is characterized by being provided.

Further, according to the present invention, the water-cooled pipe has a pipe diameter capable of passing cooling water at a flow rate which can sufficiently withstand the radiant heat emitted from the molten metal and / or the slag layer held inside the ladle. Characterize.

[0020]

In such a water-cooled ladle lid, in order to reduce the heat energy that is originally carried away by the cooling water as much as possible and save energy, the diameter of the water-cooling pipe and the material of the water-cooling pipe constituting this water-cooling structure should be adjusted. First, the heat conduction of the structure by dimensional shape (surface area, sealing property of each opening, etc.), temperature control and flow rate of cooling water, and lining a refractory material with heat insulation on the surface of the water cooling pipe group. Although there are conceivable countermeasure technologies that mitigate and adjust the characteristics, it is not possible to solve with such countermeasure technologies alone, and it is not always satisfactory in terms of accuracy and reliability. Construction cost is too high to be economical.

In the present invention, as a result of various investigations and experiments conducted to achieve the above-mentioned actual situation and the object of the present invention in the ladle lid having such a water cooling structure, the molten metal is refined as described above. I thought about positively using the splash splash that occurs inevitably.

That is, at the time of refining the molten metal as described above, the splash is generated from the molten metal and the slag, which is undesirably scattered. If this is adhered to the surface of the water cooling pipe group on the inner surface of the water cooling structure, He conceived that the reality and tasks could be achieved relatively easily and economically.

However, the splash layer, which is desired to be adhered and used as a substitute for a heat-resistant refractory material, easily peels off and falls, or conversely exceeds the suitable state and causes an abnormal thickness, shape, or place with an unintended thickness. It does not have the effect if it grows and is formed.

In consideration of the above points, the present invention is constructed as described in the above [Means for Solving the Problems]. Therefore, the splash layer should be grown so as to be maintained in a suitable state. , The splash that splashes on the water cooling pipe that is located inside the circular opening of the ladle most easily is peeled off, and it is placed on the water cooling pipe surely so that it does not fall, and it is coated as a starting point. It became possible to grow a splash group up to the tube to form a stable splash layer, which made it possible to realize the idea of easing and controlling heat conduction.

In addition, when the splash layer is formed in this way, if the amount of the adhered layer increases and this may cause a problem in refining operation and equipment, that is, the load of the splash layer cannot be supported. Or, if the splash layer grows further downward from the bottom of the ladle lid to create a gap between the ladle and the lid, or if it goes into the gap, cross it and divide it. The lowermost lid portion and its corresponding cooling passage and the splash layer adhered to and supported by this cooling passage are separated from each other to provide a new lowermost lid portion and its corresponding cooling passage. It is possible to replace it with a replacement part consisting of, and the replacement work is easy, and it is not necessary to have many spares for the entire ladle lid in a small operation site, and it is possible to quickly respond to the refining operation. Than it is.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A water cooling ladle lid of a refining ladle in a vacuum refining apparatus will be described in detail below as an embodiment according to the present invention with reference to the drawings. FIG. 1 is a schematic vertical sectional view of a vacuum refining apparatus according to an embodiment of the present invention. The vacuum refining device 1 is
A vacuum container system including a vacuum container 1a and a vacuum container lid 1b, an exhaust gas duct 4 and an exhaust means 5 connected to the vacuum container system.
An exhaust system consisting of, a ladle 6 placed at a predetermined position in the vacuum vessel 1a every time the molten metal and slag are held and refined, and a ladle 6 at the bottom for stirring the molten metal and slag It is formed by a gas supply system comprising a gas supply means 3 for supplying an inert gas such as argon gas through the gas injection nozzles 2a and 2b.

An oxygen top blowing lance 7 is provided on the vacuum container lid 1b.
Is provided so as to be vertically movable up and down, and hoppers 8a and 8b for supplying metal / alloy and flux for increasing the amount of molten metal, adjusting the component composition, and refining are attached.

During the vacuum refining operation of the molten metal, the gas supply system is driven from the gas injection nozzles 2a, 2b at the bottom of the ladle 6 while the exhaust system is driven to keep the vacuum container 1a in a depressurized state. An inert gas is blown into the molten metal to stir, and oxygen is blown from the lance onto the molten metal in the ladle 6 for decarburization refining.

The ladle 6 is formed by a ladle body 9 having a circular opening edge and a water-cooling ladle lid 10, and the lid 10 is placed on the circular opening edge of the body 9 so as to be openable and closable. The molten metal held inside is sealed as much as possible to suppress the temperature drop thereof and to prevent the molten metal from flowing out of the body 9 and splash of splash out of the body 9.
The water-cooled ladle lid 10 is a hat-shaped lid having a water-cooled structure, and is attached to the reinforcing member 13 serving as an outer shell and the inner surface side of the ladle body 9 facing the internal space. And a cooling passage 11.

FIG. 2 shows an enlarged cross-sectional view of the main portion of the lid 10 shown in FIG. 1 indicated by reference numeral A, and FIGS. 3 and 4 are plan views in which a part of the lid 10 is omitted. A front view is shown. With reference to FIGS. 1 to 4, the reinforcing member 13 is formed in a split structure that is divided into at least two parts, an upper part and a lower part, in a circular slice shape. This embodiment is divided into three parts, a lower part 13A, an intermediate part 13B and an upper part 13C, and each joint surface part is provided with a coupling means 14 which will be described later and is detachably integrally coupled to each other. A hat-shaped split outer shell is formed.

On the other hand, the cooling passage 11 is realized by a water cooling pipe made of a steel pipe. The water cooling pipe 11 is closely attached to the reinforcing member 13 so that there is no gap as much as possible.
A curved pipe bent in an arc shape is provided over the entire surface of the lid 10 where cooling is required, and in a multi-stage concentric arrangement with respect to the central axis O of the lid 10, and adjacent pipe ends are folded pipes. They are connected by 12 and are formed into fluid passages having, for example, a concentric circle shape or a zigzag spiral shape as a whole. The cooling passage 11 formed by winding the water cooling pipe 11 in such a state corresponds to the respective portions 13A, 13B, 13C of the reinforcing member 13 and includes three independent lower portions, an intermediate portion and an upper portion. It is formed into a divided structure divided into passages, and cooling water is passed through each passage.

Among the cooling passages 11 of the three parts, the passage of the lowermost multi-stage concentric diameter has the largest first-stage portion at the bottom, as shown in an enlarged view in FIG. The water-cooled pipes 11A, which are formed in a state of being arranged in series in close contact with each other in the same horizontal plane while forming an arc shape along the edge portion, and which are located most inside the circular opening of the ladle body 9, Immediately above it, the second-stage water cooling pipe 1
1B is provided so as to project in the direction of the central axis O in the circular opening of the ladle body 9. In the example shown in FIG. 2, the first
First and second water-cooled pipes 11 from the central axis O of the tier
The second-stage water cooling pipes 11B are arranged so as to be mounted on the valley portions of both the water cooling pipes 11A and 11C with respect to A and 11C.
In addition, the innermost water cooling pipe 11A of the first stage and the water cooling pipe 11B of the second stage have the same concentric diameter of the water cooling pipe 11A.
In contrast to that of B, the diameter of the water cooling pipe 11 is increased by ½ or more, that is, the water cooling pipe 11A projects in the direction of the central axis O by more than the radius of the water cooling pipe 11B immediately above it. It is arranged so that the relationship is established. Each water-cooled pipe 11 is formed by brazing and welding adjacent pipes except for the insertion port 11h of the oxygen top blowing lance 7 shown in FIG. 4, the duct insertion port 11i of the hoppers 8a and 8b, and the gas vent port. It is attached so as not to create voids.

FIG. 5 is an enlarged perspective view of the coupling means 14 shown in FIG. The coupling means 14 includes the lower reinforcing member 13
Lower coupling member 1 provided on the joining surface of the upper end of A
5, an upper coupling member 16 provided on the joining surface portion of the lower end portion of the reinforcing member 13B in the middle portion, and a wedge 17 for wedge-fitting both members 15, 16. Lower coupling member 1
Reference numeral 5 denotes a pair of steel plate pieces that are erected upright in the space between the inner surface of the reinforcing member 13A and the water cooling pipe 11 so as to face each other in the front-rear direction and are fixed to the reinforcing member 13A by welding. On the other hand, the upper coupling member 16 is made of a single steel plate piece that is vertically provided in the space between the inner surface of the reinforcing member 13B and the water cooling pipe 11, and is fixed to the reinforcing member 13B.
When the 3A and 13B are joined, they are positioned so as to be sandwiched between the pair of steel plate pieces of the lower coupling member 15. The connecting members 15 and 16 are provided with holes 18 made of square holes for fitting the wedges 17 therein.

Two or more coupling means 14 are provided at positions where the circumference of the lid 10 is equally divided. In addition, in order to integrally join the lid portions of the middle portion and the upper portion of the lid 10, each joining surface portion is provided with joining means having the same structure.

The water-cooled ladle lid 1 of the embodiment having the above-mentioned structure
0 joins the upper part, the middle part and the lower part,
It is integrally connected with the ladle main body 9 and is placed on the edge of the circular opening of the ladle body 9 so as to be openable and closable. In this way, the ladle 6 is installed at a predetermined position in the vacuum container 1a, and the vacuum refining process operation is performed. During this treatment operation, the splash is vigorously scattered, especially due to the boiling of CO gas during the blowing of oxygen gas. After the scattered splash adheres to the inside of the ladle lid 10, the splash is cooled and contracted on the surface of the water cooling pipe 11. Water cooling tube 11A and water cooling tube 1
Since the concentric diameter of 1B is different and the former is larger, the splash that is placed on the water cooling pipe 11A and adhered between both pipes 11A and 11B does not separate from the water cooling pipe 11 even when cooled and shrinks, and also falls. If not, it stabilizes in that position. This state is shown by the hatched area B in FIG. Then, once it remains stably in this portion, from this portion as a starting point, the hatched areas B and C shown in FIG. As a result, the splash adheres to the inner surface of the all-water cooling pipe 11 formed in the multistage concentric arrangement. However, the attached splash, when its thickness reaches a certain value,
It reduces the cooling capacity of the splash surface (inner exposed surface),
No further splash growth occurs. As a result, the surface of the water-cooled pipe 11 has a reduced thermal conductivity as in the case where a refractory which is a heat insulating material is additionally provided, so that the temperature of the molten metal and the slag is suppressed, and the temperature is increased. Can be maintained in a state.

During the vacuum refining process, if the thickness of the splash attached around the water cooling pipe 11 reaches a constant value, the splash once attached will drip into the main body 9 thereafter. As shown in the state, there is a portion Sa that hangs along the water cooling pipe 11A located inside the lowermost stage. If the sagging portion Sa grows sufficiently, there is a problem that it flows between the main body 9 and the lid 10 to deteriorate the sealing property, and it becomes difficult to mount the lid 10 on the main body 9. As the growth progresses in this way, it becomes repeatedly unusable and it becomes necessary to replace the lid 10.

In this embodiment, the entire lid 10 is not replaced, only the sectioned lower part is replaced, and the middle part and the upper part can be reused repeatedly. The procedure of the replacement work in this case will be described with reference to FIGS. 6 and 7. While removing the wedge 17 of each coupling means 14 provided on the joint surface portion between the lower portion and the middle portion of the ladle lid 10 where the hanging portion Sa of the splash has occurred to the extent shown in FIG. 6,
The respective joint portions of the uppermost water cooling pipe 11 in the lower cooling passage and the lowermost water cooling pipe 11 in the middle cooling passage are separated. After that, when the lid portion where the upper portion and the intermediate portion of the lid 10 are integrally coupled is lifted by a hoist such as a dedicated truck or a crane, as shown in FIG. 7, the cooling passages 11 in the upper portion and the intermediate portion, Since the reinforcing members 13C and 13B are integrally lifted, the lower cooling passage 11, the lower reinforcing member 13A, and
The cone-shaped splash S and the splash S remain as one unit.

Next, the remaining portion is removed from the main body 9, a new replacement part consisting of the lower reinforcing member 13A and the lower cooling passage 11 is placed on the main body 9, and the lid part that has been lifted is lowered and It is placed on top and integrally connected by the connecting means 14. In this way, the new lid 10 can be attached to the main body 9 only by exchanging some members.

FIG. 8 is a cross-sectional view of a main part of a lid 10 which is another embodiment of the present invention. The other embodiment shown in FIG. 8 is similar to the embodiment shown in FIG. 2, and corresponding members are designated by the same reference numerals. In the other embodiment shown in FIG. 8, it should be noted that the other cooling passages 11 except the lowermost one are formed by steel square ducts. A baffle plate 19 for circulating cooling water in a zigzag shape is provided in the rectangular duct, and has a structure capable of improving cooling efficiency. In the other embodiment, by separating the water cooling pipe 11 provided in the lowermost stage from the square duct, the cooling passage formed of the square duct can be reused in the same manner as the above-described embodiment shown in FIG. It is sufficient to replace only the water cooling pipe 11 of.

Next, an experimental example of the vacuum refining process using the embodiment of the present invention will be shown. Using the water-cooled ladle lid 10 shown in FIG. 1, which is an example of the present invention, 75 ton of molten stainless steel was vacuum-refined. Splash that adhered after starting the process and heating 108 times (the number of times of refining used)
Since the suspending load on the equipment was exceeded, only the lower portion of the lid 10 was replaced and the molten steel was again subjected to the vacuum refining treatment.
The transition of the temperature drop of the treated molten steel when treated up to 108 heats is as shown in Table 1 below.

[0041]

[Table 1]

As is apparent from Table 1 above, after the start of the treatment, the temperature drop is reduced by 10 ° C. to 6 ° C. with respect to the temperature drop of up to 15 heats, and when the number of times of heat is more than that, it shows a substantially constant value. It is clear that the temperature can be maintained at a high temperature because the heat removal can be reduced and the temperature drop of the molten steel can be suppressed.

[0043]

As described in detail above, the water-cooling ladle lid of the metal refining ladle according to the present invention is formed by winding a water-cooling pipe made of steel while winding it into a hat shape. Under the condition that the water cooling pipe group corresponding to the eaves (overhanging) extending around this hat is arranged in a specific positional relationship with the water cooling pipe immediately above it. Is formed in a split structure that is divided into at least two parts, an upper part and a lower part, in a sliced shape, and a joining means for detachably and integrally joining is provided on the joining surface portion, while inside the ladle of this lid. The cooling passage provided for guiding the cooling water to the inner surface side facing the space is formed under the condition that it is formed as an independent passage corresponding to each divided lid portion.

By implementing such a configuration,
We positively utilize the splash that is generated and scattered from the molten metal and slag held inside the ladle,
This attachment of the splash can be ensured, and the subsequent growth of the splash to a predetermined thickness can be promoted and maintained in a stable and strong state.

By virtue of the presence of the splash layer which is maintained and has a heat insulating property in this way, refining operation can be performed while preventing the temperature drop of the molten metal, and the overheating of the lid of the water cooling ladle can be prevented to extend the service life of the lid itself. Can be planned.

Further, in particular, this water cooling ladle lid is divided into at least two parts, an upper part and a lower part, in a sliced shape, and the cooling passage is also formed as an independent passage corresponding to this, so that the lid lower part is formed. Even when the splash layer has grown abnormally such as hanging down, or even during normal times, it is possible to replace only the lower lid part and replace it, and the other lid parts can be reused repeatedly. And cost can be significantly reduced. Moreover, it is not necessary to store a large number of spare parts for the water cooling ladle lid, and the storage space is not increased.

Therefore, it goes without saying that the problems of the conventional ladle lid having the refractory structure described in the above items (a) to (e) can be solved, and various problems in the conventional ladle lid having the water cooling structure can be solved. It is very convenient for problems, especially for replacement work involving maintenance such as removal of the water-cooled ladle lid from the ladle and removal of splash from this lid. Of the water-cooled ladle lid according to the present invention that can achieve stable and efficient refining operation over a long period of time while achieving the object of the present invention while achieving economic efficiency through energy saving. It has a great industrial value.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a vacuum refining apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a lid 10 shown in FIG.

3 is a partially omitted plan view of a lid 10 shown in FIG. 1. FIG.

FIG. 4 is a front view of the lid 10 shown in FIG.

5 is an enlarged perspective view of the coupling means 14 shown in FIG.

FIG. 6 is an explanatory view of a growing state of splash in the lid 10 shown in FIG.

7 is an explanatory diagram of a replacement procedure of the lid 10 shown in FIG. 1. FIG.

FIG. 8 is a sectional view showing a main part of a lid 10 according to another embodiment of the present invention.

[Explanation of symbols]

 6 Ladle 9 Ladle body 10 Water cooling ladle lid 11 Cooling passage 13 Reinforcing member 14 Coupling means 15 Lower coupling member 16 Upper coupling member 17 Wedge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Sudo 4976 Nomura Minami-cho, Shinnanyo-shi, Yamaguchi Prefecture Shunan Steel Works (72) Inventor Isao Ueki 4976 Nomura-minami-cho, Shinnanyo-shi, Yamaguchi Nisshin Shunan Steel Works, Ltd.

Claims (3)

[Claims] 1. A water-cooled ladle lid that is openably and closably mounted on a circular opening edge of a ladle used for metal refining, and has a cooling passage for guiding cooling water to an inner surface facing the inner space of the ladle. , The water-cooled ladle lid is formed in a divided structure that is divided into at least two parts, an upper part and a lower part, in a sliced shape, and a joining means for detachably and integrally joining is provided on a joining surface portion, A water cooling ladle lid for a metal refining ladle, wherein the cooling passage is formed as an independent passage corresponding to each of the divided lid portions. 2. A cooling passage is formed in a hat shape by a water cooling pipe wound so as to be installed as much as possible, and is arranged in series in a horizontal direction at the lowermost stage which abuts on a circular opening end edge of a ladle. The water-cooling pipe located closest to the central axis in the circular opening of the ladle of the water-cooling pipe group is provided so as to project more than the radius of the water-cooling pipe in the central axis direction with respect to the water-cooling pipe immediately above it. The water-cooled ladle lid of the ladle for metal refining according to claim 1. 3. The water-cooled pipe has a pipe diameter capable of passing cooling water at a flow rate that can sufficiently withstand the radiant heat emitted from the molten metal and / or the slag layer held inside the ladle. The ladle lid of the ladle for metal refining according to claim 2.