JPH0797612A - Ladle refining degassing apparatus for molten steel - Google Patents

Abstract

PURPOSE:To provide a molten steel ladle refining degassing apparatus which can omit a work for shifting the ladle between tanks and can profitably prevent the temp. drop of the molten steel in the ladle, by using a common tank for the ladle refining process and the degassing process. CONSTITUTION:The common tank 1 arranged in a traveling truck 3 is provided with a shell body for incorporating the ladle 2 stored with the molten steel and a lining refractory layer. A first tank cover 71 is descended at a ladle refining station 7 and put on the common tank 1 and the molten steel is heated by graphite electrodes 76 and the alloy is added to the molten steel from an adding part 78 and the slag refining is executed, Successively, the traveling truck 3 is self-propelled to a degassing station 8 along a rail part 39. After slag-off there, a second tank cover 81 is descended and put on the common tank 1, and the vacuum device 86 is operated to execute the degassing treatment to the molten steel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten steel ladle refining degassing apparatus for carrying out both a ladle refining process and a degassing process of molten steel in a ladle.

[0002]

2. Description of the Related Art In casting, molten steel melted and refined in a melting furnace is stored in a ladle, and the molten steel in the ladle is cast into a mold. More recently, in the stage before casting,
By further refining the molten steel stored in the ladle in the ladle, it is attempted to further improve the quality of steel products.

In such ladle refining, conventionally, for example, the process shown in FIG. 8 has been performed. That is, using the traveling carriage 801 holding the ladle 800, the molten steel melted in the electric furnace 802 is stored in the ladle 800 on the traveling carriage 801 and then the LF is stored.
In the (Ladle-Furnace) process, a pan lid 805 equipped with a graphite electrode rod 804 through which a three-phase alternating current is energized is used, and a peripheral edge portion 805c of the pan lid 805 is attached to an upper opening peripheral edge portion 800c of the pan 800, State, graphite electrode rod 8
While the molten steel is heated by the arc generated between 04 and the molten steel, slag refining is performed with high basicity slag to remove impurities. Next, in the RH process, the vacuum container 806 is used,
The immersion pipe 807 of the vacuum container 806 is immersed in the molten steel of the ladle 800, and argon gas is supplied to the argon passage 808 of the vacuum container 806 to send the molten steel of the ladle 800 to the vacuum container 806, where the molten steel is removed. Gas treatment is being carried out. Furthermore, for ladle refining, a fixed type ladle refining tank was used, and the ladle containing molten steel was moved to the storage room of the ladle refining tank each time, and the graphite electrode rod A technique for removing impurities by performing slag refining with high basicity slag while heating the molten steel by an arc generated between the molten steel and the molten steel has been developed (Japanese Patent Laid-Open No. Sho 63-63).
No. 171247). In this conventional technique, the ladle refining tank is dedicated to the ladle refining process.

Further, conventionally, for degassing treatment, a fixed type degassing tank is used, and a ladle storing molten steel is moved to a degassing tank storage chamber each time, and the tank inside is kept in that state. Techniques for degassing molten steel by suction have also been developed. In this conventional technique, the degassing dedicated tank performs only the degassing process.

[0005]

SUMMARY OF THE INVENTION The present invention is a further advancement of the steelmaking technology described above. By using a common tank for the ladle refining process and the degassing process, the ladle is transferred between the tanks. An object of the present invention is to provide a molten steel ladle refining degassing device which can eliminate the work of changing and is advantageous in preventing the temperature drop of the molten steel in the ladle.

[0006]

A molten steel ladle refining and degassing apparatus of the present invention comprises a first fixing portion installed on the floor surface, and a first tank lid suspended from the first fixing portion so as to be vertically movable. Ladle refining including a first elevating / lowering drive unit for elevating and lowering the first tank lid, a graphite electrode rod for penetrating the first tank lid from top to bottom to heat molten steel, and an addition unit for adding an alloy to the molten steel Station, a second fixing part fixed to the floor surface via a rail part led out from the ladle refining station, and a second fixing part which is hung up and down so as to be able to move up and down so as to correspond to the peripheral part of the first tank lid. Degassing station having a second tank lid having a peripheral portion and an exhaust port connected to a vacuum device, and a second elevating / lowering drive unit for raising and lowering the second tank lid, a ladle refining station, and a degassing station A traveling carriage that can travel along a rail that connects between A storage chamber having a top opening for holding and holding a ladle that stores molten steel, and a top opening peripheral edge portion where the peripheral edge portion of the first tank lid and the peripheral edge portion of the second tank lid are individually attached and sealed. It has a common tank and has a common tank used in both the ladle refining station and the degassing station.

[0007]

In the storage room of the common tank held by the traveling carriage, a ladle storing molten steel is stored. In a state where the traveling carriage is arranged at the ladle refining station, the first lifting drive unit is driven to lower the first tank lid,
The peripheral portion of the first tank lid is attached to the peripheral portion of the upper opening of the common tank and is sealed. With such adhesion, the molten steel in the ladle is heated by the graphite electrode rod, and the alloy is added to the molten steel in the ladle from the addition part, so that the molten steel in the ladle floats on the molten steel surface. Ladle refining with slag,
The ingredients are adjusted.

When the work at the ladle refining station is completed, the first elevating and lowering drive unit moves in reverse to raise the first tank lid, and the first tank lid is removed. After that, the traveling carriage is guided to the rail portion and transferred to the degassing station. Then, the second elevating / lowering drive unit is driven to lower the second tank lid, and the peripheral edge portion of the second tank lid is attached to the upper peripheral edge portion of the common tank and is sealed. When the vacuum device is driven in such a deposited state, the inside of the common tank is depressurized or evacuated, and the molten steel in the ladle is degassed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. (Structure of Embodiment) First, description will be made with reference to FIGS. The common tank 1 has a container-shaped steel shell 11 having a storage chamber 10 and an open upper surface 10e, a refractory layer 12 provided on the inner peripheral portion of the shell 11, and an outer diameter of the shell 11. It is provided with a pair of wing-shaped flange portions 13 protruding in the direction, and a ladle holding portion 14 provided on the inner peripheral portion of the shell 11. The common tank 1 is provided with a shaft-shaped trunnion guide portion 15 having a flange 15a. Trunnion guide 15
Thereby, there is an advantage that the trunnion box 25 of the ladle 2 described later is guided to facilitate the positioning of the ladle 2.
A feed pipe 16 is arranged in the common tank 1. One end of the feed pipe 16 is connected to the porous portion at the bottom of the ladle 2, and the other end is connected to a gas supply device (not shown).
The argon gas for bubbling and stirring the molten steel in the ladle 2 is fed via the.

As described above, the ladle holding portions 14 are provided so as to project radially inward on the inner peripheral portion of the shell body 11, and two ladle holding portions 14 are provided so as to face each other. Further, the ladle holder 14 is formed with a square groove-shaped holding groove 17 having an open upper surface. The rectangular groove-shaped holding groove 17 is divided by sides 17a to 17c. The bottom port 1x of the common tank 1 has a bottom opening 1c
Is provided, and the bottom opening 1c is closed by a removable plug 18. The stopper 18 is opened and closed by a cylinder 19. Bottom opening 1
The c is equipped with a temperature sensor 1u such as a thermocouple.

The ladle 2 has a container-shaped iron skin 20 and an iron skin 20.
1 is provided with a refractory layer 21, a molten steel storage chamber 22 defined by the refractory layer 21, and a spout 23 for pouring molten steel in the molten steel storage chamber 22. The refractory layer 21 is preheated to about 900 to 1100 ° C. before the molten steel storage. A square box-shaped trunnion box 25 and a support shaft 26 are projectingly provided on the iron skin 20 of the ladle 2. The trunnion box 25 mainly reinforces the ladle 2. The trunnion box 25 and the rectangular groove-shaped holding groove 17 have corresponding shapes and dimensions, and the rectangular box-shaped trunnion box 2 of the ladle 2 is provided.
By fitting 5 into the holding groove 17 in the shape of a square groove, the ladle 2
Are detachably held in the common tank 1. When the ladle 2 is held by the common tank 1 as described above, there is a gap 1h between the inner wall surface of the storage chamber 10 and the outer wall surface of the ladle 2.
In the refining (AR) step described below, the temperature of the refractory layer 12 in the common tank 1 reaches about 300 to 600 ° C. for an interval of 1 h. Furthermore, the axis P1 of the ladle 2 and the axis P of the common tank 1
It is eccentric with 2. If the ladle 2 is stored in the storage chamber 10 of the common tank 1 by the crane by eccentricity in this way,
The advantage that the work of removing the hook of the crane that suspends the support shaft 26 of the ladle 2 becomes easy is obtained. There is also a space 1i between the bottom wall surface of the storage chamber 10 and the bottom portion 2y of the ladle 2.

FIG. 7 shows the vicinity of the upper opening peripheral edge portion 1s of the common tank 1. As shown in FIG. 7, a ring-shaped seal groove 1α is formed substantially coaxially in a steel ring frame 1ε that constitutes the upper surface of the upper surface opening peripheral edge portion 1s,
A ring-shaped heat-resistant rubber-based seal material 1β is held in the seal groove 1α. Further, a ring-shaped water cooling passage 1γ is formed. The sealing material 1β and the ring frame 1ε are protected by the cooling by the water cooling passage 1γ.

Next, description will be made with reference to FIGS. 3 and 4. The traveling vehicle 3 is self-propelled and has a beam portion 30, a fixed portion 31, a drive motor 32, a drive shaft 33, wheels 34, a control panel 35, and a stopper portion 36. Drive shaft 32 by drive motor 32
Is driven to rotate the wheels 34, whereby the traveling carriage 3 travels along the rail portion 39 in the directions of arrows X1 and X2.
The traveling carriage 3 approaches the waste container 38 by traveling.

As shown in FIGS. 3 and 4, the common tank 1 described above is mounted on the traveling carriage 3. That is, the bracket 1e provided on the wing-shaped flange portion 13 of the common tank 1 is mounted on the elevated portion 31c of the fixed portion 31 of the traveling carriage 3 via the support shaft 1f.
It is rotatably pivoted to. Here, as can be understood from FIG. 4, the support shaft 1f is arranged not at the center of the common tank 1 but at an end-side biased position.

Hydraulic tilting cylinder 4 as tilting device
Is provided between the traveling carriage 3 and the common tank 1.
The tilting cylinder 4 is rotatably supported by the fixed portion 31 via a shaft 40, and the tip of the rod 42 of the tilting cylinder 4 swings to the bracket 13x of the winged flange portion 13 of the common tank 1 via the shaft 43. It is movably pivoted. As shown in FIG. 5, a bracket 11r is fixed to the shell 11 of the common tank 1.

As can be seen from FIG. 5, the gutter member 5 is formed of an outer frame 50 and an inner frame 52j exchangeably held by the outer frame 50. The inner frame 52j has a refractory layer 52 made of castable having a passage 51 for passing slag and molten steel. Arm part 50 connected to the outer frame 50 of the gutter member 5
w is rotatably supported by the bracket 11r via a shaft 50i.

Further, as shown in FIG. 5, the bracket 1x of the common tank 1 is provided with a hydraulic gutter cylinder 5 via a shaft 54x.
4 are pivoted. The gutter cylinder 54 is equipped with a cylinder cover 54r. The tip of the cylinder rod 55 of the gutter cylinder 54 is pivotally supported by the sub-bracket 50k of the outer frame 50 of the gutter member 5 via a shaft 55r. Therefore, when the gutter cylinder 54 is extended as shown by the solid line in FIG. 5, the shaft 55r rotates in the direction of the arrow C1 along the locus arc R1, and the gutter member 5 is turned sideways as shown by the solid line in FIG. , The position of use. At this time, as shown in FIG.
End 5x of the gutter member 5 rotates about a locus arc R2 around the axis 50i, and the end 5y of the gutter member 5 rotates around a locus arc R3 around the axis 50i. As described above, in the use position, the one end portion 5m of the gutter member 5 has the spout 2 of the ladle 2 in the storage chamber 10.
3, the other end 5n of the gutter member 5 faces the common tank 1, and the gutter member 5 is bridged.

When the gutter cylinder 54 contracts as shown by the alternate long and short dash line in FIG. 5, the shaft 55r rotates in the direction of arrow C2 along the locus arc R1 and the gutter member as shown by the alternate long and short dash line in FIG. 5 is the standby position, which is oriented vertically. Next, description will be made with reference to FIG. At the ladle refining station 7, a refining (AR) process is carried out. AR is Advanced-
Abbreviation of Refining, ladle refining by slag floating on the molten steel surface in ladle 2, adjustment of molten steel composition by ladle refining, and heating of molten steel by arc heating are performed.

Here, in the ladle refining station 7, a fixed frame 7 as a first fixing portion fixed to the floor F1.
0, the first tank lid 7 that opens and closes the upper opening of the common tank 1.
1, a suspension cylinder 73 as a first lifting drive unit fixed to the fixing unit 72, a traveling carriage stopper 74, a chain 75
Is provided. The chain 75 is connected between the rod 73v of the suspension cylinder 73 and the suspension 71c of the first tank lid 71, and connects the first chain portion 75a, the second chain portion 75b, and the third chain portion 75c. Have. The first tank lid 71 is suspended by the chain 75 so as to be able to move up and down in the directions of arrows E1 and E2. The fixed frame 70 has three
Gas supply device 7 having a graphite electrode rod 76, a graphite electrode rod elevating device 77, an addition portion 78 having an alloy inlet 78a, and an argon gas supply pipe 79a connected to the first tank lid 71.
9 is equipped.

Next, in FIG. 6, a degassing (LD) process is carried out in the degassing station 8. LD is Ladle
Degassing is an abbreviation for degassing. Here, in the degassing station 8, a fixed frame 80 serving as a second fixing portion fixed to the floor surface F1, a second tank lid 81 that opens and closes an upper surface opening of the common tank 1, and a second fixing portion 82 fixed to the fixing portion 82. A lifting cylinder 83 as a lifting drive unit, a traveling carriage stopper 84, and a chain 85 are provided. The chain 85 is the rod 8 of the lifting cylinder 83.
3v and the suspending tool 81c of the second tank lid 81 are continuously provided, and the first chain portion 85a and the second chain portion 85 are provided.
It has b and the 3rd chain part 85c. The second tank lid 81 is suspended by the chain 85 so as to be able to move up and down in the directions of arrows F1 and F2. Further, the exhaust port 86 is provided in the common tank 1.
It is equipped with a vacuum device 86 for reducing or vacuuming via f, a supply device 88 for supplying argon gas to the supply pipe 16 for bubbling of molten steel, and an addition part 89 having an alloy inlet 89a.

When used, the melting material, limestone, carburizing agent, alloy, etc. are melted in a basic electric furnace (lining material: magnesia system) to form molten steel having a composition close to the final composition. In this example, this molten steel has a final composition of SCM420 series. The final composition of the SCM420 system is generally 0.20% C, 0.25% Si, 0.60-0.85% Mn, 0.003% or less P, 0.90 Cr. ~ 1.20%, Mo 0.15 ~ 0.30%,
Oxygen is usually 20PPM or less, nitrogen is usually 20-250P
It is about PM. In this example, the composition is basically adjusted in an electric furnace so as to obtain such a final composition, further roughly adjusted according to the analysis value in the ladle refining process, and finely adjusted in the degassing process.

Ladle 2 is prepared by melting molten steel in the electric furnace as described above.
Store in. The ladle 2 storing molten steel is stored in a storage chamber 10 of a common tank 1. Then, the traveling carriage 3 provided with the common tank 1 in a state where the ladle 2 storing molten steel is stored is self-propelled along the rail portion 39 and is transferred to the ladle refining station 7. Like this, ladle refining station 7
When the chain 7 is reached, the lifting cylinder 73 operates and the chain 7
5, the first tank lid 71 descends in the direction of the arrow E2, and the peripheral edge portion 71r thereof has an upper surface opening peripheral edge portion 1s of the common tank 1.
The common tank 1 is closed by the first tank lid 71. The state immediately before closing is shown in FIG.

In the closed state as described above, the graphite electrode rod elevating device 77 is operated, the graphite electrode rod 76 is inserted into the common tank 1 from the electrode insertion opening of the first tank lid 71, and the graphite electrode rod 76 is inserted. The molten steel in the ladle 2 is heated by the arc heating by, and the temperature is adjusted. Also, the alloy from the addition section 78 is ladle 2.
It is appropriately added to the molten steel inside. As the alloy to be added,
Examples include ferroalloys such as ferrosilicon, ferromanganese, and ferromolybdenum, carburizing agents, and fluorspar. As a result, a basic slag of the required composition is generated on the molten steel surface, and ladle refining to remove impurities is actively performed by this slag (so-called slag refining), and the composition of molten steel in the ladle 2 is increased. Coarsely adjusted. The basic composition of slag is Ca by weight%
_{O55~60%, SiO 2 8~15%,} Al 2 0 3 10
˜20%, and MgO and CaF ₂ several%.

In this state, argon gas is supplied to the molten steel in the ladle 2 from the above-mentioned feed pipe 16 and stirring by bubbling is performed. In the refining (AR) step, argon gas is fed into the common tank 1 from the argon gas feed pipe 79a of the gas feeding device 79, and the atmosphere in the common tank 1 is also argon gas. The refining (AR) step is performed as described above. The molten steel temperature in the refining (AR) process depends on the material, but is generally 1550 to 1700 ° C.
It is a degree. The time required for the refining (AR) step depends on the capacity of the ladle 2, but is generally 30 to 120 minutes. In such refining (AR) process, since the ladle 2 is covered with the common tank 1, even if molten steel or slag leaks from the ladle 2, the leaked molten steel or slag can be received in the common tank 1. The safety is improved, and since the ladle 2 is covered with the common tank 1, the common tank 1 has an effect of blocking molten steel from the outside air, and also has an improved heat shielding property.

When the refining (AR) step is completed as described above, the heating by the graphite electrode rod 76 is stopped and the suspension cylinder 73 is moved in the reverse direction to move the first tank lid 71 to the arrow E1.
Raise in the direction. Then, the traveling vehicle 3 is transferred to the degassing station 8 via the turntable 9 and the rail portion 39. Next, slag is discharged with the traveling carriage 3 still installed in the degassing station 8. That is, the gutter member 5 is bridged between the common tank 1 and the ladle 2, and in that state, the tilting cylinder 4 is operated to rotate the common tank 1 in the direction of the arrow T1, as can be understood from the phantom line in FIG. Move. Then, the ladle 2 tilts together with the common tank 1. This is because the square box portion of the trunnion box 25 of the ladle 2 is fitted into the rectangular holding groove 17 so that the ladle 2 is housed in the common tank 1. When the ladle 2 tilts in this manner, the slag floating on the molten steel surface from the pouring port 23 of the ladle 2 is discharged to the slag container 38 together with some molten steel.

Next, the lifting cylinder 83 operates as described above. Then, the second tank lid 81 is connected via the chain 85.
Is lowered in the direction of arrow F2 to move to the peripheral edge portion 8 of the second tank lid 81.
1r is attached to the common tank 1, and the second tank lid 81 closes the common tank 1. In such a closed state, the vacuum device 86 operates to reduce the pressure or vacuum so that the pressure in the common tank 1 becomes 0.5 Torr or less, and thereby gas components such as oxygen, hydrogen, and nitrogen in the molten steel are removed. Degas to remove. Further, the alloy is appropriately added to the molten steel in the ladle 2 from the addition section 89, and the composition of the molten steel in the ladle 2 is finely adjusted. The alloy to be added is basically the same as that in the refining (AR) step, but the addition amount is small in the degassing (LD) step due to the fine adjustment of the composition. In the degassing (LD) step, argon gas is blown into the molten steel in the ladle 2 and the molten steel is stirred. The time required for the degassing (LD) step depends on the capacity of the ladle 2, but is generally 10 to 30 minutes.

When the degassing (LD) step is completed in this way, the suspension cylinder 83 is moved in the reverse direction to raise the second tank lid 81 in the direction of arrow F1. Further, in order to prevent the ladle 2 from being lifted from the common tank 1, the gutter cylinder 54 is driven so that the gutter member 5 is oriented vertically as shown by the alternate long and short dash line in FIG. Next, the ladle 2 is lifted by a crane to remove the ladle 2 from the common tank 1. Then, molten steel is poured from the ladle 2 into the tundish of the continuous casting device to perform continuous casting. Or cast into an ingot.

(Effects of the Embodiment) By the way, by shortening the transition time for transition to the subsequent process, it is possible to prevent the temperature of the molten steel in the ladle 2 from decreasing. In this respect, in this embodiment, since the common tank 1 is used in the ladle refining process and the degassing process, the traveling carriage 3 holding the common tank 1 accommodating the ladle 2 in which molten steel is stored is attached to the rail portion 39. If the vehicle is driven along with it, it is possible to shift from the ladle refining process to the next degassing process. That is, it is not necessary to transfer the ladle 2 between the tanks. Therefore, the process transition time can be shortened,
It is possible to prevent a decrease in molten steel temperature due to the process transition. Therefore, the heating temperature of the molten steel in the ladle 2 in the ladle refining process does not have to be excessively high and can be made lower than in the case of transferring the ladle 2 between tanks. Therefore, when the molten steel is heated by arc heating with the graphite electrode rod 76 in the ladle refining process, it contributes to prevention of consumption of the graphite electrode rod 76, prevention of excessive electricity, and prevention of wear of the refractory layer 21 of the ladle 2. it can.

In this embodiment, the first tank lid 71 is equipped with equipment used in the ladle refining process, and the second tank lid 81 is equipped with equipment used in the degassing process. Is. However, the peripheral portion 71r of the first tank lid 71 and the peripheral portion 81r of the second tank lid 81 are of the same type, and basically have the same shape.
This corresponds to the peripheral edge portion 1s of the upper surface opening. Therefore, when the common tank 1 is closed, good sealing performance can be expected in the boundary area between the upper surface opening peripheral edge portion 1s of the common tank 1 and the peripheral edge portion 71r of the first tank lid 71. Similarly, good sealability can be expected in the boundary region between the upper surface opening peripheral edge portion 1s of the common tank 1 and the peripheral edge portion 81r of the second tank lid 81. Therefore, in the refining (AR) process and the degassing (LD) process, it is possible to avoid the entry of the outside air into the common tank 1, and it is possible to contribute to the further improvement of the quality of the steel product.

In addition, in this embodiment, the ladle 2 can be discharged from the common tank 1 at the place where the degassing process is performed, without removing it. Therefore, it is possible to quickly shift from the slag process to the degassing process, and to suppress the decrease in molten steel temperature as much as possible, which can contribute to the improvement of the quality of steel products and also to the reduction of operating time. Further, in this embodiment, as can be understood from FIG. 2, when the ladle 2 is housed in the common tank 1, the ladle 2
Since the square box portion of the trunnion box 25 is fitted into the holding groove 17 having a square groove shape, the ladle 2 cannot relatively swing in the common tank 1, and the ladle 2 is integrated with the common tank 1. It tilts. Therefore, if the common tank 1 is tilted, the ladle 2 can be tilted automatically.

In addition, in this embodiment, the bottom opening 1 of the common tank 1
Since c is equipped with a temperature sensor 1u such as a thermocouple, when molten steel leaks from the ladle 2 or slag overflows from the ladle, the abnormal state can be detected. In addition, since the temperature sensor 1u is provided in the common tank 1, the temperature sensor 1 can be separated from the ladle 2 having high heat, and the protection of the temperature sensor 1u can be improved.

Further, the refractory layer 12 of the common tank 1 generally has a temperature of 300 to 300 due to its high temperature and long heating time when the molten steel is heated in the refining (AR) step.
It is heated to a high temperature range of about 600 ° C. In this way, the common tank 71 in which the refractory layer 12 is heated to a high temperature region is degassed (L
Since it is used in the step D), the heat retaining property of the common tank 1 in the degassing (LD) step is ensured, which is advantageous in suppressing the temperature decrease of the molten steel in the ladle 2.

(Other Examples) The material of the molten steel is not limited to those mentioned above, but other alloy steels, stainless steels, etc. can be adopted. The composition of the slag is not limited to that described above, and can be adjusted as appropriate. The fixed frames 70 and 80 may be connected to each other.

[0034]

According to the device of the present invention, since the common tank is used in the ladle refining process and the degassing process, the railcar is used for the traveling carriage that holds the common tank in which the ladle storing molten steel is stored. If the vehicle is driven along with it, it is possible to shift from the ladle refining process to the next degassing process. That is, it is not necessary to transfer the ladle between the tanks. Therefore, the transition time can be shortened and the molten steel temperature can be prevented from lowering. Therefore, the heating temperature of the molten steel in the ladle in the ladle refining process can be made lower than in the case of transferring the ladle between tanks. Therefore, when the molten steel is heated by arc heating with the graphite electrode rod in the ladle refining process, it is possible to contribute to prevention of consumption of the graphite electrode rod, prevention of excessive amount of electricity, and prevention of wear of the refractory layer of the ladle 2.

According to the apparatus of the present invention, the peripheral portion of the first tank lid and the peripheral portion of the second tank lid are aligned with each other, and basically have the same shape and structure, and the upper surface of the common tank. It corresponds to the peripheral edge of the opening. Therefore, when the common tank is closed, good sealing performance can be expected in the boundary area between the peripheral portion of the common tank and the peripheral portion of the first tank lid. Similarly, good sealability can be expected in the boundary area between the peripheral portion of the common tank and the peripheral portion of the second tank lid. Therefore, it is possible to avoid the entry of outside air in the ladle refining process and the degassing process, which can contribute to further improvement in the quality of steel products.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a ladle is stored in a common tank.

FIG. 2 is a configuration diagram showing a cross section of a state in which a ladle is stored in a common tank.

FIG. 3 is a plan view of a traveling carriage equipped with a common tank holding a ladle.

FIG. 4 is a side view of the traveling carriage equipped with a common tank holding a ladle.

FIG. 5 is an enlarged side view near the gutter member.

FIG. 6 is a side view showing a ladle refining station and a degassing station.

FIG. 7 is a cross-sectional view in the vicinity of a peripheral portion of an upper surface opening of a common tank.

FIG. 8 is a process chart according to a conventional technique.

[Explanation of symbols]

In the figure, 1 is a common tank, 10 is a storage room, 2 is a ladle, 3 is a traveling carriage, 7 is a ladle refining station, 70 is a fixed frame, 71 is a first tank lid, 73 is a hanging cylinder, and 76.
Is a graphite electrode rod, 78 is an addition part, 8 is a degassing station, 80 is a fixed frame, 81 is a second tank lid, 83 is a hanging cylinder, 86 is a vacuum device, and 86f is an exhaust port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Okubo 1 Wano Wari, Arao Town, Tokai City, Aichi Prefecture Aichi Steel Works

Claims (1)

[Claims] 1. A first fixing part installed on a floor surface, a first tank lid suspended from the first fixing part so as to be able to move up and down, and a first elevating drive part for elevating the first tank lid. , A ladle refining station equipped with a graphite electrode rod that penetrates the first tank lid from top to bottom to heat molten steel, and an addition section for adding an additive to the molten steel, and derived from the ladle refining station A second fixing part fixed to the floor surface via a rail part, a peripheral part that is suspended from the second fixing part so as to be able to move up and down, and corresponds to the peripheral part of the first tank lid, and are connected to a vacuum device. A degassing station having a second tank lid having an exhaust port for opening and closing, and a second elevating / lowering drive unit for raising and lowering the second tank lid, and a rail connecting the ladle refining station and the degassing station. Trolley that can travel along the section, and a molten trolley that is held by the trolley and stores molten steel A common tank having a storage chamber having an upper surface opening for accommodating a ladle and an upper surface opening peripheral portion where the peripheral edge portion of the first tank lid and the peripheral edge portion of the second tank lid are individually applied and sealed. A molten steel ladle refining degassing apparatus, characterized in that the common tank is used in both the ladle refining station and the degassing station.