JP5504953B2 - Ladle equipped with an accumulator cylinder type gas blowing device - Google Patents

Description

  The present invention relates to a ladle provided with an accumulator cylinder type gas blowing device.

  In steelmaking plants, molten steel produced from molten iron by decarburization and refining in a converter is discharged into a ladle and then desulfurized and refined in a ladle at a secondary refining facility such as a ladle refining furnace. Secondary refining such as component adjustment is applied. In this secondary refining, an inert gas such as Ar gas is generally used as an agitation gas from a refractory material called “blowing plug” installed at the bottom of the ladle for the purpose of promoting the reaction and homogenizing the molten steel. As is blown into the molten steel. A porous plug or a slit plug is used as the blowing plug.

  Conventionally, gas is blown from the blow plug during secondary refining, and gas is not blown during other periods, that is, during conveyance or continuous casting, and molten steel or hot metal passes through the blow plug. There was a problem that the gas could not be blown by being inserted into the pores and closing the vent holes.

  In order to solve this problem, Patent Document 1 discloses a ladle provided with a pressure accumulation cylinder type gas blowing device detachably attached to the side surface or bottom of the ladle, and the pressure accumulation cylinder type gas blowing device. Is a main pipe which is a gas path for blowing gas from an independent gas supply source through a gas blowing plug to the ladle, a pressure accumulation cylinder having a function of accumulating gas through the main pipe, and the main Simultaneously with the start of gas blowing through the pipe or during the gas blowing, the gas is accumulated in the accumulator cylinder, and the gas is injected into the accumulator cylinder at the same time as the gas injection is completed through the main pipe. A ladle equipped with a pressure-accumulation cylinder type gas blowing device, characterized in that it includes a control unit having a function of switching to ”.

  In FIG. 3, the schematic structure part of the ladle disclosed by patent document 1 is shown. In FIG. 3, reference numeral 1 is a ladle, 2 is molten steel (molten metal), 3 is a blow plug, 4 is a gas supply source, 5 is a pressure accumulation cylinder type gas blower, 6 is a control unit, 7 is a pressure accumulation cylinder, Reference numeral 8 denotes a main pipe, which accumulates gas in the accumulator 7 during the secondary refining, and injects the gas accumulated in the accumulator 7 through the control unit 6 during a period other than during the secondary refining. This is a technique for preventing the air vent of the blow plug 3 from being blocked by continuing to flow at a low flow rate. In this case, when the gas accumulated in the pressure accumulation cylinder 7 decreases, the gas is supplied from the gas supply source 4 to the pressure accumulation cylinder 7 in a continuous casting facility or the like, and the gas from the blowing plug 3 continues to flow. is there.

JP 2003-239010 A

  The ladle equipped with a pressure accumulating cylinder type gas blowing device proposed in Patent Document 1 significantly improves the plugging of the blowing plug, and does not require oxygen cleaning when the plug is plugged. An extremely remarkable effect that the number of uses is also increased.

  However, during secondary refining, the gas is automatically accumulated in the accumulator, and after secondary refining, the gas accumulated in the accumulator is automatically blown into the molten steel. In the case of a steel grade that needs to be “still set” later, a new problem arises that it cannot be applied. In the case of Ca-added steel, the vapor pressure of Ca is high, and if the molten steel after adjusting the Ca concentration is stirred, Ca in the molten steel may be gasified and the Ca concentration may be lower than the standard value. In addition, since the molten steel temperature is lowered by stirring, even if the molten steel temperature during secondary refining or after secondary refining is reduced to near the solidification temperature for some reason, it remains a target regardless of the type of steel. It becomes. Here, “standing still” means that the molten steel is not forcibly agitated.

  When refining steel grades that need to be left after secondary refining, a valve (valve) can be installed in the accumulator cylinder type gas blowing device to prevent the gas in the accumulator cylinder from flowing out. Since each secondary refining facility such as a furnace has various gas connection positions, a large number of expensive valves for heat resistance are required in order to be able to cope with each facility, which is not economical.

  The present invention has been made in view of the above circumstances, and the purpose of the present invention is in a ladle equipped with a pressure-accumulation cylinder type gas blowing device, in the case of containing molten steel that needs to remain after secondary refining. Is to provide a ladle equipped with an accumulator cylinder type gas blowing device capable of allowing the molten steel to stand still without blowing gas from the accumulator cylinder.

A ladle equipped with a pressure accumulating cylinder type gas blowing device according to the present invention for solving the above-mentioned problems is a main path that is a path for supplying gas supplied from a gas supply source to a blowing plug arranged in the ladle. Piping, a pressure accumulation cylinder for accumulating gas supplied through the main pipe as gas for blowing from the blow plug, and a blow plug at the same time as or from the start of blowing from the blow plug of the gas supplied through the main pipe During the injection, the gas supplied through the main pipe is accumulated in the pressure accumulation cylinder, and on the other hand, the gas injection from the pressure accumulation cylinder is automatically performed simultaneously with the end of the gas injection supplied through the main pipe. A pressure accumulating cylinder type gas blowing device provided with a pressure accumulating cylinder type gas blowing device provided on the side surface or the bottom thereof. In the pot,
A diffusion valve directly connected to the pressure accumulation cylinder is provided in the vicinity of the connection portion between the main pipe and the gas supply source, and the gas accumulated in the pressure accumulation cylinder is released into the atmosphere by opening the diffusion valve. It is configured.

  According to the present invention, in the case of molten steel that needs to be left after secondary refining, by opening the diffusion valve directly connected to the pressure accumulation cylinder, the gas in the pressure accumulation cylinder is released to the atmosphere, and from the pressure accumulation cylinder. Gas blowing is not performed, and the molten steel in the ladle can be allowed to stand.

It is the schematic of the ladle provided with the pressure accumulation cylinder type gas blowing apparatus which concerns on this invention. It is the schematic which shows the structure of the pressure accumulation cylinder type gas blowing apparatus arrange | positioned at the ladle shown in FIG. It is the schematic of the ladle provided with the conventional pressure accumulation cylinder type gas blowing apparatus.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view of a ladle equipped with a pressure accumulator type gas blowing device according to the present invention.

  As shown in FIG. 1, a ladle 1 for containing molten steel 2 discharged from a converter (not shown) and performing secondary refining in a secondary refining facility such as a ladle refining furnace, One or more refractory blow plugs 3 are installed at the bottom. The blowing plug 3 is for blowing an inert gas such as Ar gas or nitrogen gas into the molten steel 2 in the ladle during secondary refining in order to stir the molten steel 2. As the blowing plug 3, a porous plug or a slit plug is usually used.

  An accumulator cylinder type gas blowing device 5 is disposed on the side surface of the ladle 1 as a device for supplying the stirring gas to the blowing plug 3. The accumulator cylinder type gas blowing device 5 is branched from the main pipe 8 which is a path for directly supplying the gas supplied from the gas supply source installed in each factory to the blowing plug 3. The control part 6 and the pressure accumulation cylinder 7 provided so that it may be located in parallel are provided. The pressure accumulation cylinder 7 is a device for accumulating the gas supplied through the main pipe 8, and the control unit 6 supplies the gas to the pressure accumulation cylinder 7 when the blowing gas from the blowing plug 3 is supplied through the main pipe 8. On the other hand, when the supply of gas through the main pipe 8 is stopped, the gas accumulated in the pressure accumulation cylinder 7 is automatically switched as the gas blown from the blow plug 3. In addition, in FIG. 1, although the pressure accumulation cylinder type gas blowing apparatus 5 is arrange | positioned at the side surface of the ladle 1, it is also possible to arrange | position at the bottom face of the ladle 1. FIG.

  Further, the accumulator cylinder type gas blowing device 5 has two gas receiving portions, a first connection joint 9 and a second connection joint 10, as a connection portion with a gas supply source installed in each factory. Has been. The first connecting joint 9 is installed near the upper end of the ladle 1, and the second connecting joint 10 is installed below the center in the height direction of the ladle 1. This is a measure for accumulating gas in the accumulator 7 in the secondary refining facility or continuous casting facility, and it is difficult to connect to a gas supply source installed in each factory if the gas receiving portion is one place. Because. Further, a diffusion valve 11 for releasing the gas accumulated in the pressure accumulation cylinder 7 to the atmosphere is installed at the tip of the path directly connected to the pressure accumulation cylinder 7.

  The accumulator cylinder type gas blowing device 5 will be described in detail with reference to FIG. FIG. 2 is a schematic view showing a configuration of a pressure-accumulation cylinder type gas blowing device arranged in the ladle shown in FIG.

  The accumulator cylinder type gas blowing device 5 is provided with a first connecting joint 9 and a second connecting joint 10 as a connecting portion with a gas supply source 4 installed in each factory. The first connection joint 9 is connected to the main pipe 8, and the other end of the main pipe 8 is connected to the blowing plug 3. The main pipe 8 is provided with a check valve 12 on the first connection joint 9 side, an on-off valve 21 on the blow plug 3 side, and a connection between the check valve 12 and the on-off valve 21. A check valve 13 is provided therebetween. The gas supplied from the gas supply source 4 is ejected from the blowing plug 3 through the first connecting joint 9, the check valve 12, the check valve 13 and the on-off valve 21. Here, the check valve is a valve for preventing the gas from flowing back to the gas supply side, and the on-off valve is a valve for stopping or flowing the gas by opening and closing the valve.

  The second connecting joint 10 is connected to the main pipe 8 between the check valve 12 and the check valve 13 via the check valve 14, and the gas supplied from the second connecting joint 10 is In the same manner, it is ejected from the blow plug 3.

  The main pipe 8 is branched between the check valve 12 and the check valve 13, and the branched pipe is connected to the control unit 6. The piping constituting the control unit 6 is provided with a check valve 15, a pressure reducing valve 16, a pressure gauge 17, a flow meter 18, an on-off valve 19 and a check valve 20 in this order from the upstream side of the gas flow. The downstream side of the check valve 20 is connected to the main pipe 8 between the check valve 13 and the on-off valve 21. Further, in the control unit 6, a pipe branches between the check valve 15 and the pressure reducing valve 16, and the branched pipe is connected to the pressure accumulation cylinder 7. A safety valve 22 is installed in the pressure accumulation cylinder 7, and a diffusion valve 11 is installed in a pipe connecting the control unit 6 and the pressure accumulation cylinder 7. The diffusion valve 11 is provided in the vicinity of the installation position of the first connection joint 9, and is configured such that one operator can attach and detach the first connection joint 9 and operate the diffusion valve 11.

  When gas is supplied from the gas supply source 4 installed in each factory to the main pipe 8 via the first connection joint 9 or the second connection joint 10, the on-off valve 19 of the control unit 6 is closed, The gas supplied from the gas supply source 4 is ejected from the blow plug 3 via the main pipe 8 and is simultaneously accumulated in the pressure accumulation cylinder 7 via the check valve 15. In this case, the pressure is accumulated until the pressure of the gas accumulated in the pressure accumulation cylinder 7 becomes equal to the pressure of the gas supplied from the gas supply source 4. However, when the gas supply from the gas supply source 4 is stopped before the pressure is stored in the pressure storage cylinder 7 until the pressure of the gas supplied from the gas supply source 4 becomes equal to the pressure of the gas, the pressure is not sufficiently stored in the pressure storage cylinder 7. Thus, the pressure accumulation in the pressure accumulation cylinder 7 is completed.

  On the other hand, if the gas supply from the gas supply source 4 to the main pipe 8 is stopped, the open / close valve 19 of the control unit 6 is opened, and the gas accumulated in the pressure accumulation cylinder 7 is reduced to the pressure reducing valve 16, the pressure gauge 17, It is configured to eject from the blow plug 3 via the flow meter 18, the on-off valve 19 and the check valve 20. The opening / closing of the opening / closing valve 19 is configured to automatically operate depending on whether or not gas is supplied from the gas supply source 4. For example, the opening / closing valve 19 is operated according to an opening / closing signal of the check valve 13. You can do it. The gas accumulated in the pressure accumulation cylinder 7 is decompressed by the decompression valve 16, and the flow rate to be discharged is adjusted. The pressure gauge 17 measures this pressure, and the flow meter 18 is a device for measuring the gas flow rate.

  In this way, the control unit 6 uses the gas supplied through the main pipe 8 simultaneously with the start of the blowing from the blowing plug 3 and during the blowing from the blowing plug 3. Has a function of automatically switching the gas blown from the blowing plug 3 to the gas from the pressure collecting cylinder 7 simultaneously with the end of the gas blowing supplied through the main pipe 8. Yes.

  In the secondary refining equipment, gas is blown into the molten steel 2 from the blow plug 3 through the first connection joint 9, and at the same time, the gas is accumulated in the pressure accumulation cylinder 7. In the case of the molten steel 2 that does not need to be left after secondary refining, the gas accumulated in the pressure accumulation cylinder 7 is continuously blown from the blow plug 3 at a flow rate of about 2 to 4 NL / min, and the blow plug 3 is blocked. To prevent.

  On the other hand, in the case of the molten steel 2 that needs to be left after secondary refining, if the gas supply through the first connecting joint 9 is stopped after the completion of the secondary refining, the diffusion valve 11 is opened. Then, the gas accumulated in the pressure accumulation cylinder 7 is released to the atmosphere. As a result, the accumulated gas disappears in the pressure accumulation cylinder 7, the gas blowing from the blowing plug 3 is stopped, and the molten steel 2 is in a stationary state.

  The steel type that needs to be kept after the secondary refining is determined (for example, Ca-added steel), and after the secondary refining of the steel type, the release valve is moved back and forth when the connection of the first connection joint 9 is released. By opening 11, the molten steel 2 can be placed in a stationary state. Even when the molten steel temperature at the end of the secondary refining is lowered to near the solidification temperature, it is desirable to open the diffusion valve 11 and leave the molten steel 2 in a stationary state regardless of the steel type.

  Thus, according to this invention, since the molten steel 2 can be made into a stationary state as needed, it becomes possible to prevent quality abnormalities, such as off-specification of Ca component of Ca addition steel. Moreover, when the molten steel temperature falls close to the solidification temperature for some reason, it is possible to prevent a further temperature drop by placing the molten steel 2 in a stationary state, which is caused by low heat during casting in continuous casting. It becomes possible to suppress the inability to cast.

DESCRIPTION OF SYMBOLS 1 Ladle 2 Molten steel 3 Blowing plug 4 Gas supply source 5 Accumulation cylinder type gas blowing device 6 Control part 7 Accumulation cylinder 8 Main piping 9 1st connection joint 10 2nd connection joint 11 Divergence valve 12 Check valve 13 Check valve 14 Check valve 15 Check valve 16 Pressure reducing valve 17 Pressure gauge 18 Flow meter 19 On-off valve 20 Check valve 21 On-off valve 22 Safety valve

Claims (1)

A main pipe that is a path for supplying gas supplied from a gas supply source to a blowing plug disposed in the pan, and a pressure accumulation cylinder that accumulates gas supplied through the main pipe as gas for blowing from the blowing plug. And simultaneously with the start of blowing from the blowing plug of the gas supplied through the main pipe or during blowing from the blowing plug, the gas supplied through the main pipe is accumulated in the accumulator cylinder, A pressure accumulating cylinder type gas blowing device comprising a control unit having a function of automatically switching to gas blowing from the pressure accumulating cylinder simultaneously with the end of gas blowing supplied through the main pipe. In the ladle provided with a pressure accumulation cylinder type gas blowing device provided at the bottom,
The dissipation valve is directly connected to the pressure accumulating bomb is provided in the vicinity of the connecting portion between the main pipe and the gas supply source, when opening the dissipating Chiben is, the gas accumulated in the accumulator cylinder is released into the atmosphere An accumulator cylinder type gas blowing device , wherein gas is not supplied from the accumulator cylinder to the blowing plug and gas is not blown from the blowing plug. The prepared ladle.

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