JPH04108952U - Slag cutting determination device - Google Patents

Abstract

(57) [Summary] [Structure] A flow meter 9 and a pressure gauge 8 are arranged in an inert gas supply pipe 6 whose tip is an inert gas discharge port 2 that opens into the nozzle 1, and the inside of the nozzle 1 is measured. A sloping determination device is provided with a mechanism for detecting the vicinity where a decrease in the flow rate of flowing molten steel 5 and an increase in pressure occur simultaneously. [Effect] The nozzle is closed based on this detection data or signal. This prevents slag from being transferred, and therefore, cleaner steel can be obtained more easily than before.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a slag (slag, steel slag, blast furnace slag, etc.) cut determination device. elaborate between the ladle and the tundish, or between the ladle and the mold, or between the tundish and the ladle. In order to block the slag passing through the nozzle for transferring molten steel installed between continuous casting molds, etc. It relates to a device that makes necessary judgments.

0002

[Prior art]

Traditionally, slag cutting is used to remove slag that has flowed onto the surface of molten steel in a tundish. Visually check and based on this, block the sliding nozzle of the ladle and remove the ladle. The flow of molten steel is prevented by preventing the flow of slag into the steel plate. This is detected using an electromagnetic induction device that utilizes the difference in electrical properties between the flow of slag and the flow of slag.

0003

[Problem to be solved]

However, the above-mentioned conventional groove cutting determination method or device has the following problems. be. That is, in the former method of the conventional method, since it is carried out visually, the surface of the poured molten steel may be exposed to some extent. After visually confirming the slag that has surfaced, we will use this data to block the inflow of slag. It is cut off. Therefore, after a certain amount of slag has been transferred, cut off the slag. We are trying to prevent as much as possible the transfer of slag that deteriorates quality as inclusions. For the purposes of iron and steel manufacturing, there is a drawback that the timing of the shutoff judgment is delayed. In addition, the latter of the conventional devices mentioned above uses an electromagnetic induction device, so the device becomes larger. However, it has the disadvantage of increasing maintenance costs.

0004

[Means to solve the problem]

When transferring molten steel, this invention blows into the transfer nozzle to float inclusions. The inert gas contained is always under negative pressure due to the high-speed flow of molten steel. However, the transfer At the final stage, slag begins to pass through the nozzle, but the specific gravity of this slag is 2. ．． 5 to 3.0, while that of molten steel is 7.0, which is a big difference, so the pressure The power state changes significantly. Therefore, this reduces the inert gas (Ar) during blowing. , N2, etc.) can detect changes in pressure and flow rate. Focusing on this, this This led us to come up with an idea. The gist of the present invention is as follows. That is, A flow meter is attached to the inert gas supply pipe whose tip is the inert gas discharge port that opens inside the nozzle. and a pressure gauge to simultaneously reduce the flow rate and increase the pressure of the molten steel flowing through the nozzle. A sloping determination device characterized in that it is provided with a mechanism for detecting the vicinity that occurs at times.

[0005]

[Action and effect]

Since the present invention has the above configuration, the inert gas supply has a discharge port in the nozzle. The pressure gauge and flow meter installed in the pipe are constantly under negative pressure due to the flow of molten steel being transferred at high speed. It has become. However, at the end of the transfer stage, the slag remaining on the surface layer is removed from the nozzle. It flows into the room. This slag has a specific gravity less than half that of molten steel, so the pressure The situation changes significantly. This change in pressure state increases the pressure of the inert gas being supplied. At the same time, the power to suck inert gas decreases, so the flow rate of the inert gas also decreases. Decrease. This is different from the change in flow rate caused by clogging of the molten steel flow in the nozzle. The inert gas is also pressurized. Therefore, the pressure and flow rate of this inert gas can be increased. A sensor detects the vicinity of the point in time when both reduction and reduction are satisfied at the same time. This detection data The nozzle will be closed based on the signal. As a result, Noro was transferred. It is possible to block the occurrence of This allows for slag control with fewer errors than before, resulting in cleaner molten steel. It can also be supplied to the mold. Therefore, slabs with few inclusions or continuous casting Cast pieces can be obtained. In addition, pressure gauges and flow meters installed for inert gas supply In addition to being able to be used as is, the device configuration is simple and maintenance costs are low.

[0006]

【Example】

An embodiment of the present invention will be described based on the drawings. Figure 1 shows the nozzle when transferring from the ladle to the tundish via the nozzle. The flow rate and flow rate of the inert gas (Ar) supplied to the pipe that supplies inert gas into the chamber Figure 2 is an explanatory diagram of the pressure gauge, flow meter, etc. installed to detect pressure and pressure. shows the pressure/flow rate and time of the inert gas discharged into the long nozzle as coordinates. This is a graph. 1 is a long nozzle attached to a ladle (not shown). 2 is the long A porous brick part built into the nozzle 1, which is a nozzle 1 for inert gas (Ar) 7. It serves as an inward discharge port. 3 is the molten steel flow flowing down inside the long nozzle 1. be. Reference numeral 4 denotes a tundish that collects the molten steel flow 3 and floats inclusions. 5 is , is the molten steel stored in the tundish 4. 6 is the porous brick part 2 is a supply pipe for inert dregs 7 having a discharge port. 8 is in the middle of the supply pipe 6 It is a pressure gauge that measures and displays the pressure of the inert gas 7 that is installed and flows through it. . 9 is arranged in series with the pressure gauge 8 in the middle of the supply pipe 6, and the water flowing therethrough is This is a flow meter that measures and displays the flow rate of inert gas 7. 10 is the pressure gauge 8 and Compare the data from each flowmeter 9 and calculate whether the specified conditions are satisfied at the same time. It is a computer that does 11 is a display (table) for displaying the results of the calculations; indicator). Next, the functions and effects of the above embodiment will be explained. The molten steel in the ladle is released by opening a sliding nozzle (not shown). The liquid flows down through the nozzle 1 at a rate of 3 to 4 m/Sec. This molten steel flow 3 flows into the porous brick part. 2, the inside of the supply pipe 6 is sucked at a pressure of 1.1 atm and a flow rate of 120 liters/min. be done. Therefore, the molten steel flow 3 is mixed with fine bubbles of the inert gas 7. , is stored in the tundish 4. At this time, the molten steel 5 is mixed with The inclusions that are contained in the inert gas 7 adhere to the fine bubbles of the inert gas 7, float to the surface, and are removed. . However, the residual molten steel in the ladle decreases, and the slag on the surface layer 3, it flows into the long nozzle 1. Due to this inflow, the molten steel immediately before Compared to the specific gravity of molten steel in the case of flow 3, the specific gravity of the slag is smaller, so long nozzle 1 The pressure inside the tank has changed significantly, and based on this, the waste that was blowing out from the The pressure of the active gas (Ar) 7 increases to 1.3 atm, and at the same time, it is inhaled. The attraction drops and the flow rate decreases to 100 liters/min. This is illustrated by FIG. This is calculated by taking pressure 12 and flow rate 13 on the vertical axis and time on the horizontal axis. , the fluctuations are displayed on a graph, which is input into the computer 10 and operated. As a result, the pressure 12 increases to 1.3 atm and the flow rate 13 decreases to 100 liters/min. Zone A near the intersection point (in Figure 2, the area sandwiched between two vertically drawn parallel lines) : Slag cutting zone) is detected and displayed on the display 11. The operator adjusts the slide direction of the ladle based on the information on the display 11. to prevent the slag in the ladle from flowing into the tundish 4. Stop. As a result, cleaner molten steel 5 is placed in the tundish 4 than before. can accumulate. Therefore, in addition to making it easier to float inclusions, continuous There is also less slag entrapment in the casting mold (not shown), and therefore more inclusions. We were able to obtain slabs with less Also, compared to conventional electromagnetic induction devices, the It was easy to install, and the installation and maintenance costs were low. Note that the present invention is not limited to the above-mentioned examples, and does not go against the gist of the present invention. For example, if the conditions of A zone are satisfied, It is also possible to add an alarm device to the sliding nozzle opening/closing mechanism. , it is also possible to send this data signal and automatically close the sliding nozzle. It falls within the technical scope of the proposal.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the structure of an embodiment.

FIG. 2 is a graph showing pressure/flow rate and time as coordinates in the example.

[Explanation of symbols]

1. ...Long nozzle 2. ...Porous brick part (discharge port) 3. ...molten steel flow 4. ...Tundish 5. ...molten steel 6. ...supply pipe 7. ...Inert gas 8. ...pressure gauge 9. ……Flowmeter 10. ...computer 11. ……display 12. ……pressure 13. ...Flow rate A. ...Slag cutting zone

Claims (1)

[Scope of utility model registration request] Claim 1: A flow meter and a pressure gauge are disposed in an inert gas supply pipe having an inert gas discharge port opening in a nozzle at its tip, and molten steel or molten pig iron (hereinafter simply referred to as molten steel) flows through the nozzle. What is claimed is: 1. A sloping determination device characterized by being provided with a mechanism for detecting a vicinity where a reduction in flow rate and an increase in pressure occur simultaneously.