JPS6159368B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a refining device.

In recent years, the quality conditions required for metal materials such as steel have become increasingly strict, and in order to satisfy these quality conditions, long-term refining using, for example, an electric furnace is required. However, conducting refining for a long time using an electric furnace is not preferable because it leads to a decrease in productivity and an increase in energy costs. Therefore, the adoption of the out-of-furnace refining method is becoming more popular.
Special refining methods such as ladle refining are increasingly being adopted.

Figure 1 shows an example of a conventional ladle refining device, in which a tiltable table 2 is mounted on a cart 1.
The ladle 3 is placed on the table 2, and a top cover 5 is placed on the upper end of the ladle 3 via an elastic O-ring 4. And at the bottom of ladle 3
A porous plug 6 is provided as an outlet for inert gas such as Ar gas to stir the molten steel 10 in the ladle 3, and a support shaft 8 is attached to the side wall of the ladle 3 to transport the ladle 3. I am trying to do this. In addition, an opening 5a for exhaust gas and electrode insertion is formed in the upper lid 5, and an opening 5b for adding alloy elements is formed in the upper lid 5, and the exhaust duct 12 is installed with the blind lid 11 installed in one opening 5a. The structure is such that the molten steel 10 can be heated by inserting an electrode (not shown) with the blind lid 11 removed, and the other opening 5b has an alloy shooter 15 connected to the lower end of the alloy hopper 14. It has a structure that allows it to be attached. In addition, exhaust duct 1
Expandable joints 16 and 17 are attached to the alloy shooter 2 and the alloy shutter 15, respectively.

When refining molten steel 10 using such a ladle refining device, a ladle 3 containing molten steel 10 is placed on a tiltable table 2 as follows. That is, during the slag removal work, the ladle 3 is tilted together with the tilting table 2 to drain the slag above the molten steel. In addition, heating and stirring the molten steel 10 in the ladle,
When adding slag or alloy, etc., after moving the cart 1 to the heating and refining position, place the upper lid 5 on the upper end of the ladle 3 via the elastic O-ring 4, and insert it into the ladle 3 through the opening 5a as shown in the figure. The molten steel 10 is stirred by inserting a non-contact electrode and arc-heated, blowing out inert gas through the porous plug 6, and adding a slag-forming agent and an alloy material as appropriate through the opening 5b. Furthermore, during vacuum processing, an electrode (not shown) is taken out from inside the ladle 3, a blind lid 11 is installed around the opening 5a via an elastic O-ring 18, and then the vacuum is evacuated by an evacuation device (not shown). That's what I was doing.

However, in such a conventional ladle refining device, the ladle 3 is placed on the tilting table 2, and the ladle 3 is placed on the tilting table 2.
Place the upper lid 5 and blind lid 11 on the upper end of the
Therefore, the ladle 3 needs to be an airtight container with a strength that can withstand vacuum, and the upper part of the ladle 3 must be a vacuum flange to maintain airtightness with the upper lid 5. And molten steel 1
Since the thermal influence from 0 is quite large, it is necessary to have a better water-cooled structure to protect the elastic O-ring 4. In addition, it is necessary to have a better water-cooled structure to protect the elastic O-ring 4. Due to the adhesion, a sealing failure with the upper lid 5 is likely to occur, resulting in problems such as a decrease in the degree of vacuum.

The present invention has been made by focusing on the above-mentioned conventional problems, and is a special metal container such as a ladle that holds molten metal such as molten steel that has high strength and airtightness that can withstand vacuum. It is possible to use a metal container such as a regular ladle, and stable vacuum processing without sealing failure is possible, making it easy to install metal containers such as ladles in the specified position and removing slag. It is an object of the present invention to provide a refining device that can perform the above operations easily and in a short period of time.

The refining apparatus according to the present invention uses electrode heating, induction heating, or other heating method to heat molten steel, etc. in a vacuum container that is tiltable on a base such as a movable table or a fixed table and that can be evacuated using a vacuum pump or the like. It is characterized by the installation of a metal container such as a ladle that can heat the molten metal.

Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.

The drawing shows a metal scouring device according to an embodiment of the present invention. In the figure, 10 is a molten metal, in this case molten steel, 20 is a vacuum container, and 50 is a metal container, in this case a ladle.

The vacuum container 20 has an elastic O at the upper end of the container body 21.
It has a structure in which a top lid 23 is installed via a ring 22, and the container body 21 is constructed by lining a castable brick inside a steel shell, for example.
For example, it is constructed by lining the inside of a water-cooled steel top cover with castable bricks. In addition, the container body 2
1 has an emergency leakage outlet 25 made of mild steel that melts and opens when the molten steel 10 leaks, and a cylindrical lid 26a that slides open by blowing air pressure. Discharge port 26
have. The lower part of the side wall of the container body 21 has an exhaust port 27, and a vacuum exhaust duct 29 is connected to the exhaust port 27 via an expansion joint 28. It is connected to vacuum evacuation equipment (vacuum pump, etc.), not shown, via this evacuation duct 29. Furthermore, a slug apron 31 driven by a pressure cylinder (not shown) is attached to the upper side wall of the container body 21 via a pivot 32, and an O-ring protector that protects the elastic O-ring from radiant heat from the inner surface of the upper lid. pivot cover 33
It is attached via 4. A ladle supporting pedestal 35 is provided inside the container body 21. moreover,
An inspection port (for example, one with an opening/closing door) is provided in the side wall of the container body 21 as necessary.

On the other hand, it is preferable that the upper lid 23 be provided with an electrode sleeve to provide heat insulation and electrical insulation from the electrodes to be described later. Further, a blind lid flange 37 is provided, and the inner lid hanger is passed through the inner lid hanger, and an inner lid 38 as a heat shield plate is suspended from the lower end of the inner lid hanger. The inner cover 38 can be constructed by lining a stainless steel end plate with castable bricks, for example, and is preferably provided with an electrode sleeve as in the case of the upper cover 23. Further, the upper lid 23 is provided with a viewing window and an opening/closing door for temperature measurement and sampling.

The vacuum container main body 21 has a trunnion shaft 41 on its side wall portion, and a bearing 4 provided at the upper end of the truck 42.
3 is fitted with the trunnion shaft 41, making it possible to tilt around this part. That is, the cylinder side of the pressure cylinder 44 is connected to the truck 42 by the pivot 4.
5, and the piston side of the pressure cylinder 44 is pivotally connected to the container body 21 via a pivot 46, so that when the pressure cylinder 44 is pushed out, the fourth
As shown by the imaginary line in the figure, after the slag apron is moved toward the ladle side, the vacuum container body 21 is tilted. Further, the truck 42 is self-propelled, has wheels 48, and has a structure in which it moves on rails 49.

When placing the upper lid 23 on the container body 21, an elastic O-ring 22 for sealing is interposed between the two to improve the degree of sealing. It is also desirable to have a structure in which a water cooling box is provided in a portion.

A ladle 50 is installed inside the vacuum container 20.
〓〓〓〓
The ladle 50 has a structure in which, for example, a steel outer shell is lined with refractory bricks, and a hook 51 formed on the side wall of the outer shell is supported by the pedestal 35 of the vacuum vessel 20. Further, a support shaft 52 is attached to the side wall of the ladle 50 so that the ladle 50 can be suspended and transported by a crane or the like (not shown). Further, a porous plug 55 is installed at the bottom of the ladle 50, and an inert gas introduction pipe 56 is connected to the porous plug 55 to supply inert gas, thereby reducing the molten steel in the ladle 50. This makes it possible to perform agitation. Note that the molten steel 10 can also be stirred by electromagnetic stirring or the like.

In the illustrated example, the ladle 50 has a structure in which three electrodes 61a, 61b, and 61c can be inserted therein. These electrodes 61a to 61c pass through openings in the inner lid 38 and the upper lid 23, and are held by electrode support arms 62a, 62b, and 62c, respectively. These electrode support arms 62a, 62
b, 62c are guide roller boxes 63, respectively.
a, 63b, and 63c, and are movable up and down along electrode masts 64a, 64b, and 64c, respectively. Guide roller boxes 63a-63
C and the electrodes 61a to 61c are raised and lowered by ropes 66a, 66b, and 66c connected to electrode support arms 62a, 62b, and 62c, respectively. That is, the rope 66 connected to the electrode support arm 62a
The rope 66b connected to the electrode support arm 62b is hung around the sheaves 67b and 69b to change the direction. The other end of the rope 66c is wrapped around the lower wire drum 71b shown in FIG.
c, 68c, and 69c to change direction, and the other end is attached to the upper wire drum 71c shown in FIG.
wrapped around the wire drums 71a, 71b, respectively.
71c is configured to be rotated by motors 72a, 72b, and 72c.

A blind lid 75 can be installed on a blind lid flange 37 provided on the upper lid 23. This blind lid 75 is
As shown in FIG. 5, it is suspended from a horizontal support arm 77a via a link chain 76, and this horizontal support arm 77a is fixed to a vertical support arm 77b, and this vertical support arm 77b is attached to a guide roller box 78. It is fixed and can be raised and lowered by a pressure cylinder 70 along a blind lid mast 79.

The electrode masts 64a, 64b, 64c and the blind lid mast 79 are all installed on a common base 80, and this base 80 is rotatably installed on a fixed base 82 via a bearing 81. , this fixed stand 82 is connected to the foundation (work floor) via the base frame 83.
Fixed. The rotation of the base 80 is performed by the fifth
As shown, this is done by a pressure cylinder 85. That is, in the illustrated example, the cylinder side of the pressure cylinder 85 is pivotally connected to the base mast 86, the piston side of the pressure cylinder 85 is pivotally connected to the base 80, and the base 80 is pivoted in response to the movement of the pressure cylinder 85.
is rotating. Note that the electrode masts 64a to 64c and the blind lid mast 79 can be attached to separate bases so that the respective bases can be rotated.

The upper lid 23 of the vacuum container 20 has a plurality of mounting arms 91.
The upper lid lifting arm 92 is moved up and down by a cylinder 93 that has a piston that moves in the vertical direction.
2. I am trying to make it go up and down.

An alloy shutter 101 is disposed at the top of the vacuum vessel 20. An expand joint 102 is provided in the middle of this alloy shooter 101. Further, an alloy hopper 103 is attached to the alloy shooter 101.

Next, the molten steel 10 is
The case of refining will be explained.

In FIG. 6, the right half side is the ladle setting position A, and the left half side is the refining position B.
Therefore, the trolley 42 is moved to the ladle setting position A, and a spindle is inserted into the vacuum container main body 21 (the vacuum container upper lid 23 is in the refining position B), which is tiltable with respect to the trolley 42 via a bearing 43. The ladle 50 suspended by 52 is set. Inside this ladle 50, molten steel 10 is melted and refined in a melting furnace or the like.
is accommodated.

Therefore, during slag removal, a pressure cylinder (not shown) is operated to set the slag apron 31 on the ladle 50 side, and then the pressure cylinder 44 is operated to tilt the vacuum container body 21 around the bearing 43, and at the same time, the ladle 50 is (Figure 3 c is the center of tilting)
Transfer the slag on the surface of the molten steel 10 to the slag apron 3
1 into the slag container 105 from above. This slag container 105 is installed on a slag container transfer trolley 106.

Next, for refining of the molten steel 10 in the ladle, such as heating, stirring, slag making, alloy addition, vacuum treatment, etc., the cart 42 is moved from the ladle setting position A to the refining position B, and the pressure cylinder 93 is operated to cover the upper lid. As the elevating arm 92 descends, the vacuum container upper lid 23 is lowered and placed on the vacuum container main body 21 via an elastic O-ring 22 for sealing.

When heating the molten steel 10, the motors 92a, 9
2b, 92c as appropriate to connect the ropes 66a, 6.
Electrodes 61a, 61b, 6 via 6b, 66c, etc.
1c, each electrode 61a, 61b, 61c
The electrode sleeve provided on the upper lid 23 and the inner lid 3
Penetrate each electrode sleeve provided in 8,
It is lowered to a predetermined height within the ladle 50. Then,
Each electrode 61a, 61b, 61 is connected to a power source (not shown).
The molten steel 10 is arc-heated by energizing the molten steel 10.

During vacuum processing, motors 72a, 72b,
72c to operate the ropes 66a, 66b, 66
The electrodes 61a, 61b, and 61c are raised through the electrodes 61a, 61b, and 61c until the lower ends of the electrodes 61a, 61b, and 61c are higher than the upper lid 23, respectively. Next, the pressure cylinder 85 is operated to rotate the base 80 and move each electrode 61a, 61b, 61c to the virtual line position in FIG. 6, and at the same time move the blind lid 75 to the center of the upper lid 23, Thereafter, the blind lid pressure cylinder is operated to lower the blind lid 75, and the blind lid 75 is installed on the blind lid flange 37 provided on the upper lid 23. In this case, the blind lid 75 is suspended by the link chain 76, and when the blind lid 75 is installed on the blind lid flange 37, most of the weight of the blind lid 75 is applied to the upper lid 23. It becomes a ivy shape. Further, it is desirable to further improve the airtightness of the vacuum container 20 by interposing an elastic sealing O-ring or the like between the blind lid 75 and the blind lid flange 37. Next, after connecting the evacuation expansion joint 28 to the exhaust port 27 formed in the vacuum container body 21, a vacuum evacuation device (not shown) is activated to evacuate the inside of the vacuum container 20.

The molten steel 10 is stirred by blowing out an inert gas through a porous plug 55 provided at the bottom of the ladle 50 during the heating and vacuum treatment.

When heating is performed after vacuum processing, the blind lid pressure cylinder is activated to raise the blind lid 75, then the pressure cylinder 85 is activated to rotate the base 80, and the blind lid 75 is moved at the same time. electrode 61
a, 61b, and 61c to the center of the upper lid 23, operate the motors 72a, 72b, and 72c, and lower each electrode 61a, 61b, and 61c through the openings of the upper lid 23 and the inner lid 38,
Thereafter, electrical heating is performed.

In this way, in the apparatus shown in this example, heating,
Because slag making, alloy addition, and vacuum treatment can be performed at the same location, work efficiency is extremely high. In contrast, in the conventional case, the ladle is placed on a trolley, the heating top cover and electrode are set at the heating position, and the vacuum processing top cover and vacuum exhaust equipment are set at the vacuum processing (degassing) position. Therefore, when moving from heating to degassing or from degassing to heating, it is necessary to raise and lower the top cover and transfer to a trolley each time, which has the drawback of low workability and low operating costs.

Therefore, in the apparatus shown in the above embodiment, since the heating and refining position and the vacuum processing position can be made the same, the ladle setting, heating and vacuum processing positions can be changed from the conventional three positions of ladle setting position, heating position and vacuum processing position. The number of processing positions can be reduced to two, the installation space for the equipment is smaller, and there is no need to move the ladle between heating and vacuum processing, so the operating time can be shortened. Moreover, since the upper lid 23 is shared and a blind lid 75 is installed during vacuum processing, equipment costs can be reduced. In addition, in the apparatus shown in the above embodiment, the ladle 5
Since the ladle 0 is kept under vacuum in the vacuum container 20, good vacuum processing can be performed even when the ladle 50 is thermally deformed, and a normal ladle 50 can be used. On the other hand, in the case where the inside of the ladle 3 is directly evacuated as shown in Fig. 1, the thermal deformation of the ladle 3 and the airtightness between it and the upper lid 5 have a large effect, and the ultimate vacuum level is not good. Otherwise, the degassing process may be insufficient or the evacuation time may be long, so a special ladle with excellent strength and high airtightness is required. Therefore, in the case of the above embodiment, it is possible to shorten the evacuation time and improve the ultimate vacuum level.
This makes it possible to shorten the processing time for degassing and degassing.
It is possible to prevent the temperature drop of molten steel as much as possible, and the temperature of molten steel is 10.
It can also be applied to ladle degassing (LD) without heating.

Furthermore, unlike the conventional method, there is no need to attach a slag apron to the ladle itself, and since the slag apron 31 is attached to the vacuum container body 21, operability during sludge removal is improved.

Furthermore, the electrode lifting device described in the above embodiment has a unique structure using a hollow mast, wire, sheave, etc. compared to the electrode lifting device used in conventional electric furnaces. There is no need to place a motor (winch) or the like on the rotating section, and therefore the rotating mechanism can be made lighter and smoother. Further, the electrode lifting device described above is effective not only in ladle scouring furnaces but also in arc furnaces and the like.

As explained above, according to the present invention, a metal container capable of heating molten metal such as molten steel is installed in a vacuum container that is tiltable and evacuated. It is not necessary for the metal container such as a ladle to hold the metal to have high strength and airtightness to withstand vacuum, and it is possible to achieve a good vacuum by using a metal container such as an ordinary ladle. Vacuum treatment is possible, and even if the ladle is thermally deformed due to aging, etc., it will not be affected by such thermal deformation, and the vacuum evacuation time can be shortened to achieve the desired vacuum. This makes it possible to shorten the vacuum processing time and reduce the temperature drop of molten metal such as molten steel, improving metal quality and reducing energy costs. Slag work, heating smelting work,
It has very excellent effects such as being able to perform vacuum processing work efficiently.

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal cross-sectional view of the main part of a conventional ladle refining device, Fig. 2 is an explanatory longitudinal cross-sectional view of the main part of a ladle refining apparatus according to an embodiment of the present invention, and Fig. 3 is the right side of Fig. 2. Fig. 4 is an explanatory view of the main part as seen from the left side of Fig. 2, Fig. 5 is an explanatory rear view of the main part as seen from the rear side of Fig. 2, Fig. 6 Figures 7 and 8 are plan explanatory diagrams showing the positional relationship of work during ladle refining.
9 and 9 are a plan view, a front view, and a side view, respectively, of the sheep attachment portion for changing the direction of the electrode lifting/lowering rope. 10... Molten steel (molten metal), 20... Vacuum container, 21... Vacuum container body, 23... Upper lid, 27
...Exhaust port, 38...Inner lid, 42...Dolly, 4
3... Bearing, 44... Pressure cylinder, 50... Ladle (metal container), 61a, 61b, 61c... Electrode, 75... Blind lid, 80... Base, 85... Pressure cylinder. 〓〓〓〓

Claims (1)

[Claims] 1. A refining device characterized in that a metal container capable of heating molten metal is installed in a vacuum container that can be tilted and evacuated.