JPH01273656A - Device for detecting clogging of submerged nozzle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a clogging detection device for a continuous casting immersion nozzle that injects molten metal into a mold from a tundish.

[Prior Art] In the casting process of continuous casting, there has conventionally been a problem that clogging occurs in the continuous casting immersion nozzle that injects molten metal from the tundish into the mold. The reason for this is that aluminum added to the molten metal becomes alumina-based inclusions that adhere and accumulate on the inner surface of the immersion nozzle. If the immersion nozzle becomes clogged, the discharge rate from the immersion nozzle will decrease, which will reduce the productivity of continuous casting.Furthermore, large alumina-based inclusions attached to the immersion nozzle in the molten metal will peel off and become trapped inside the mold. If it enters, it becomes large inclusions and causes defects in the slab. Various devices are known to prevent clogging of the immersion nozzle, but it is still difficult to completely prevent the alumina-based inclusions from adhering to the inner surface of the immersion nozzle. The current challenge is how to detect this at an early stage.

As a method for solving the above problem, for example,
Japanese Patent No. 8-125350 discloses a method for detecting clogging of the immersion nozzle. This method of detecting clogging of the immersion nozzle calculates the clogging status of the immersion nozzle from casting information such as the opening degree of the sliding nozzle, the molten metal head of the tundish, the width of the mold, the molten metal level in the mold, and the continuous casting speed. . The flow rate of the molten metal is determined by multiplying the casting speed by the surface area of the molten metal in the mold, detecting the opening of the sliding nozzle, and correcting this using the molten metal head of the tundish. By comparing the two, the degree of clogging of the immersion nozzle can be determined.

[Problems to be Solved by the Invention] However, the method for detecting clogging of an immersed nozzle disclosed in the above-mentioned Japanese Patent Application Laid-open No. 58-125350 is based on comparing the amount of molten metal flowing and the amount of molten metal flowing out. Since this is a method to determine the degree of clogging, the amount and speed of adhesion inside the immersion nozzle will vary depending on the type of molten metal and the amount of alumina inclusions mixed in the molten metal, so it is possible to detect clogging of the immersion nozzle. At that point tamp from the bottom end of the immersion nozzle. There is a problem that the alumina-based inclusions are deposited up to the upper nozzle at the bottom of the tush, requiring time to replace the immersion nozzle and reducing the productivity of continuous casting.

This invention was made to solve the above-mentioned problems, and provides a submerged nozzle clogging detection device that can promptly and accurately detect the occurrence of clogging of a submerged nozzle while the submerged nozzle is still in the state. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, the submerged nozzle clogging detection device of the present invention includes a temperature measuring device that measures the surface temperature of the submerged nozzle, and a temperature measuring device that measures the surface temperature of the submerged nozzle. A calculation device that calculates the temperature difference between the surface temperature of the immersion nozzle and a predetermined reference temperature of the surface of the immersion nozzle, and an alarm device that issues an alarm when the temperature difference calculated by the calculation device exceeds a predetermined temperature difference. It is characterized by having the following.

[Function] According to the submerged nozzle clogging detection device configured as described above, alumina adhesion progresses from the inner circumferential surface of the lower end of the submerged nozzle as casting time progresses, and is gradually deposited inside the submerged nozzle. Alumina deposition thickness increases. This increase in the alumina adhesion thickness lowers the heat transfer coefficient to the surface of the immersed nozzle, resulting in a decrease in the surface temperature of the immersed nozzle. The temperature change occurring on the surface of the immersed nozzle is continuously measured with a temperature measuring device, and at the same time, the temperature difference between the immersed nozzle surface temperature measured by the temperature measuring device and a predetermined reference temperature of the surface of the immersed nozzle is calculated. By calculating the temperature difference using the device and issuing an alarm via the alarm device when this temperature difference exceeds a predetermined temperature difference, it is possible to detect clogging of the immersion nozzle at an early stage.

[Example] Hereinafter, an example of the submerged nozzle clogging detection device of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a tundish, 2 is a sliding nozzle disposed at the bottom of the tundish 1,
3 is a driving hydraulic cylinder that drives this sliding nozzle 2; 4 is an immersion nozzle that is disposed below the sliding nozzle 2 and has a discharge hole for discharging the molten metal at opposing positions; 5 is the molten metal; and 6 is the molten metal. 5 is injected into the mold and cast to a predetermined width and thickness; 7 is the slab extracted from this mold 6; 8 is the surface temperature of the immersion nozzle 4 immersed in the molten metal 5 in the mold 6; A temperature measuring device 9, such as a thermoscope, capable of measuring at predetermined intervals, records the temperature measured by this temperature device 11'IiB, and at the same time records the temperature based on the temperature change occurring on the surface of the immersion nozzle 4. The arithmetic device 10 for calculating the difference is an alarm device such as a buzzer, which is arranged to issue a warning when the temperature difference determined by the arithmetic device 9 exceeds a predetermined temperature difference.

In the immersion nozzle clogging detection device configured as described above, the immersion nozzle 4 is immersed in the molten metal 5 in the mold 6.
The surface temperature of the immersion nozzle 4 changes as the molten metal 5 is cast.
As alumina deposition progresses within the immersion nozzle 4 and the alumina deposition thickness increases within the immersion nozzle 4, a temperature change occurs on the surface of the immersion nozzle 4. This temperature change is continuously measured by the temperature measuring device 8 and at the same time is sequentially input to the arithmetic device 9. Then, the temperature difference between the predetermined reference temperature of the surface of the immersion nozzle 4 and the surface temperature of the immersion nozzle 4 is calculated, and only when the temperature difference is outside the predetermined temperature difference, a signal is sent to the alarm device 10. This is a warning that a blockage has occurred.

Figure 2 shows the surface of the immersion nozzle 4 (5 points from the north end of the mold).
This is a graph showing temperature on the vertical axis and casting time on the horizontal axis.As is clear from this graph, the surface temperature of the immersion nozzle 4 is approximately 1 hour after the start of casting. Up to this point, the surface temperature of the immersed nozzle 4 remains at a nearly constant reference temperature of 1.100'' C, and after that, as alumina deposition progresses within the immersed nozzle 4, the surface temperature of the immersed nozzle 4 begins to decrease. The inventor believes that when the surface temperature of the immersed nozzle 4 drops to 1.060°C at point B approximately 3 hours after the start of casting, alumina is deposited to the vicinity of the upper end of the immersed nozzle 4. I was able to obtain progress results.

Based on the above results, the alarm device 10 issues an alarm when the surface temperature difference of the immersed nozzle 4 reaches 40°C or more in the arithmetic unit 9, so that even if the immersed nozzle 4 becomes clogged, only the immersed nozzle 4 By replacing the , it becomes possible to quickly solve the problem of immersion nozzle clogging.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments. Modifications such as arranging a mechanism or configuring the alarm device to be displayed on a suitable display etc. will be obvious to those skilled in the art and are within the scope of the present invention.

[Effects of the Invention] Since the present invention is configured as described above, it produces excellent effects as described below.

An alarm device that calculates the temperature difference between the surface temperature of the immersed nozzle measured by a temperature measuring device and a predetermined reference temperature of the surface of the immersed nozzle, and issues an alarm if the temperature difference exceeds a predetermined temperature difference. Since alumina adhesion can be detected early and accurately within the immersion nozzle, the immersion nozzle can be replaced quickly and the productivity of casting can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the submerged nozzle clogging detection device of the present invention, and FIG. 2 is a graph diagram showing the relationship between the surface temperature of the submerged nozzle and casting time. 1... tanditshu, 4... immersion nozzle. 5... Molten metal, 6... Mold, 8... Temperature measuring device,
9... Arithmetic device, 10... Alarm device.

Claims (1)

[Claims] In a continuous casting immersion nozzle that injects molten metal into a mold from a tundish, there is a temperature measuring device that measures the surface temperature of the immersed nozzle, and a temperature measurement device that measures the immersed nozzle surface temperature measured by the temperature measuring device and a predetermined temperature of the immersed nozzle. An immersion nozzle comprising: a calculation device that calculates the temperature difference between the surface and a reference temperature; and an alarm device that issues an alarm when the temperature difference calculated by the calculation device exceeds a predetermined temperature difference. Clogging detection device.