JP3707444B2 - Continuous casting slab cutting device and method for preventing nozzle clogging of continuous casting slab cutting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous cast slab cutting device having a torch, high-pressure water, and a nozzle for spraying, and in particular, high-pressure water for atomizing slag generated when a continuous cast slab is gas-cut using a torch. The present invention relates to a nozzle clogging prevention method for a nozzle to be used, and a continuous cast slab cutting device that has taken measures for preventing nozzle clogging.
[0002]
[Prior art]
In order to continuously cut a continuous cast slab (hereinafter simply referred to as a slab), a gas cutting device is generally used. When cutting the gas of the slab, high-purity oxygen is sprayed from a torch together with a preheating gas such as propane onto a high-temperature slab whose temperature is higher than the ignition point, and iron is oxidized to produce iron oxide. The cast slab is cut by melting the cast slab (base material) and simultaneously discharging the molten iron oxide (hereinafter referred to as slag) by the discharge pressure of oxygen.
[0003]
The slag discharged by the oxygen discharge pressure usually falls into the scale sluice disposed in the lower part of the cutting device and is carried out of the machine by the circulating water in the scale sluice. The slag produced by gas cutting has the problem that the slag particles are too large, and if they fall directly into the scale sluice, they adhere to the wall of the scale sluice and prevent stable out-of-flight transportation with circulating water in the scale sluice. It was.
[0004]
For such problems, the continuous cast slab cutting device is sprayed with high-pressure water for atomizing slag generated by gas cutting, as described in, for example, Japanese Patent Laid-Open No. 60-3953. A high-pressure water jet nozzle is installed.
[0005]
[Problems to be solved by the invention]
Normally, high-pressure water injection from a high-pressure water injection nozzle is limited when the continuous cast slab cutting device is in operation (during gas cutting), and when it is not in operation (standby), high-pressure water is shut off. Yes. However, there is a problem that when the continuous cast slab cutting device is restarted (gas cutting is restarted), the high pressure water injection nozzle is blocked and the slag cannot be atomized.
[0006]
The present invention advantageously solves the problems of the prior art described above, and prevents clogging of the high-pressure water jet nozzle in the continuous casting slab cutting device, and the nozzle clogging prevention method of the continuous casting slab cutting device and the continuous prevention of nozzle clogging. The object is to propose a cast slab cutting device.
[0007]
[Means for Solving the Problems]
The inventors examined the cause of the blockage of the high-pressure water injection nozzle. In continuous casting equipment, multiple rows of strands are installed adjacent to each other, and the cutting timing of each adjacent strand is usually not synchronized because the length of the slab to be cut differs depending on the destination and application. is there. As a result, it was found that the splash generated in the adjacent strand adhered to the tip of the high-pressure water injection nozzle during non-operation (standby) and gradually accumulated to cause nozzle clogging. For this reason, the present inventors have provided a bypass pipe in parallel with the high-pressure water supply pipe provided with an automatic shut-off valve, and provided a flow control valve in the bypass pipe to inject a small amount of water even when not in operation. It has been found that it is preferable to be able to prevent splashes from adjacent strands from adhering to the nozzle.
[0008]
The present invention is configured based on the above-described idea.
That is, the present invention relates to a continuous cast slab cutting device having a torch for gas-cutting a continuous cast slab and a nozzle for injecting high-pressure water into a slag that is scattered when the continuous cast slab is cut by the torch. The continuous cast slab cutting device is characterized in that an automatic shut-off valve is provided in a pipe for supplying high-pressure water to a nozzle, and a flow rate adjusting valve is provided in parallel with the automatic shut-off valve.
[0009]
Further, the present invention, when gas cutting a continuous cast slab using a continuous cast slab cutting device having a torch and a nozzle for injecting high pressure water, while jetting high pressure water from the nozzle, When the slab is not gas-cut, a nozzle clogging prevention method for a continuous cast slab cutting device is characterized in that a smaller amount of water is continuously ejected from the nozzle when the gas is cut.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of a continuous cast slab cutting device suitable for the present invention.
The continuous casting apparatus has a plurality of parallel strands. In the illustrated example, the continuous casting apparatus has a strand A and a strand B, and continuously casts a slab. A continuous cast slab cutting device 1 is provided for each strand, and the slab 5 is automatically cut according to a slab cutting length command from a process computer.
[0011]
The continuous cast slab cutting device 1 is provided with a torch 2 and a nozzle 3 for injecting high-pressure water. The torch 2 sprays oxygen and a preheating gas (usually propane gas) onto the slab 5 to melt the slab 5 (gas cutting). At that time, the slag 4 is generated and falls to the scale sluice 6 disposed below the continuous cast slab cutting device 1. During the fall, the slag 4 is divided into fine particles by the high-pressure water from the nozzle 3.
[0012]
In order to refine the slag, the high-pressure water is preferably injected at a pressure of 1.96 MPa (20 kgf / cm ² ) or more and a flow rate of 10 m ³ / h or more. If the pressure is less than the above range or less than the flow rate, it is difficult to shred the slag, and it is difficult to stably carry the slag out of the machine with the circulating water in the scale sluice 6.
A piping system for supplying high-pressure water in the continuous cast slab cutting device 1 is shown in FIG.
[0013]
In the continuous cast slab cutting device 1 of the present invention, a pipe 9 for supplying high-pressure water provided with an automatic shut-off valve 7 is connected to a nozzle 3 for injecting high-pressure water. When the gas is cut by the torch, the automatic shut-off valve is opened, high pressure water is supplied to the nozzle 3 for injecting high pressure water, and the slag is atomized by being injected from the nozzle. Furthermore, in the continuous cast slab cutting device 1 of the present invention, the pipe 9 is provided with a bypass pipe 10. The bypass pipe 10 is provided with a flow rate adjusting valve 8 in parallel with the automatic shutoff valve 7.
[0014]
In the present invention, when the automatic shut-off valve 7 is closed and the continuous cast slab cutting device 1 is not in operation (standby), a small amount of water is supplied to the nozzle 3 via the flow rate control valve 8 of the bypass pipe 10. Supplied. As the flow rate adjusting valve 8, a valve that can be adjusted to a low pressure / a very small region is preferable. For example, a manual ball valve or a manual ball valve is preferable.
When the continuous cast slab cutting device 1 is in a non-operating state (standby), the amount of water supplied to the nozzle 3 for injecting high-pressure water through the flow rate control valve is smaller than that during supply of high-pressure water. The pressure is preferably 0.098 MPa (1 kgf / cm ² ) or more, more preferably 0.3 MPa or less, and the flow rate is 2 m ³ / h or more, more preferably 5 m ³ / h or less. When the pressure and flow rate are less than the above range, the splash from the adjacent strands adheres and accumulates, and the frequency at which the nozzle 3 is blocked increases. Moreover, if it exceeds the above-mentioned range, the amount of water used will be large, resulting in an increase in the production cost of the slab.
[0015]
It is preferable to adjust the flow rate adjusting valve in advance so that a desired pressure and flow rate can be supplied, and always maintain the state. Thereby, a small amount of water can be injected into the nozzle 3 when the continuous cast slab cutting device 1 is not in operation (standby).
[0016]
【Example】
The slab (slab) was gas-cut using the continuous cast slab cutting device 1 provided on each of the two strands of the slab continuous casting apparatus shown in FIG. In addition, the piping system shown in FIG. 2 was used for the high pressure water supply piping system of each continuous cast slab cutting device 1.
In the strand in which the continuous cast slab cutting device is in operation, the automatic shut-off valve 7 is opened to the nozzle 3 that injects high-pressure water, high-pressure water (pressure: 1.96 MPa (20 kgf / cm ² ), flow rate: 10 m ³ / h) was supplied. On the other hand, in the non-operating strand, the automatic shut-off valve 7 is closed, and a small amount of low-pressure water (pressure: 0.098 MPa (1 kgf / cm ² ), the flow rate: 2 m ³ / h) was supplied to the nozzle 3. For each of these strands, operation and standby were repeated, and slabs for 1000 charges were continuously cut. According to such a water supply method to the nozzle 3, the nozzle 3 was not blocked at all. On the other hand, in the case of the conventional example in which high-pressure water is shut off by an automatic shut-off valve when not in operation (standby) and water is not supplied to the nozzle 3, the nozzle 3 is blocked three times in 1000 charges.
[0017]
【The invention's effect】
According to the present invention, the occurrence of nozzle clogging of a nozzle that injects high-pressure water can be prevented, and slag can be efficiently carried out of the machine, which has a remarkable industrial effect.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of a continuous cast slab cutting device suitable for the present invention.
FIG. 2 is an explanatory view showing a piping system of the continuous cast slab cutting device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Continuous casting slab cutting device 2 Torch 3 Nozzle 4 Slag 5 Slab (continuous casting slab)
6 Scale sluice 7 Automatic shut-off valve 8 Flow control valve 9 High-pressure water supply piping
10 Bypass piping

Claims (2)

A continuous cast slab cutting device comprising: a torch for gas cutting a continuous cast slab; and a nozzle for injecting high pressure water into a slag that scatters during gas cutting of the continuous cast slab by the torch. A continuous cast slab cutting device characterized in that an automatic shut-off valve is provided in a pipe to be supplied, and a flow control valve is provided in parallel with the automatic shut-off valve. When gas-cutting a continuous cast slab using a continuous cast slab cutting device having a torch and a nozzle for injecting high-pressure water, high-pressure water is jetted from the nozzle while the continuous cast slab is not gas-cut. In this case, a nozzle clogging prevention method for a continuous cast slab cutting device, wherein a smaller amount of water is continuously sprayed from the nozzle than when the gas is cut.

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