JPH01215A - Converter steel tapping completion determination method - 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 method for determining completion of steel tapping in a converter.

(Prior art and its problems) Currently, steel is manufactured in steel plants using a converter called an LD converter. During steel refining in a converter, slag called slag is present on the surface of the molten steel in the converter. Once the molten steel has been refined in the converter, the converter is tilted and the molten steel is tapped into a ladle. After the molten steel is tapped from the converter, slag on the surface of the molten steel flows into the ladle. If the completion of steel tapping cannot be appropriately determined and it is determined that -11 is completed, the molten steel yield will be low.On the contrary, if it is determined late, 70 will be mixed into the molten steel, resulting in a low quality of molten steel. Therefore, there is a need for a method to appropriately detect the completion of tapping molten steel, such as by detecting the inflow of slag into the steel tap.

Several methods have been proposed in the past for determining the completion of tapping from a converter, in other words, for distinguishing between slag and molten steel. They can be broadly classified into the following three types.

(,a) A method of detecting the contamination of slag based on the difference in electrical characteristic values (eg, resistance value, @electromotive conductivity, electromotive force) between molten steel and slag. (Unexamined Japanese Patent Publication No. 52-139805. Special Publication No. 8l-El
o, 885. Japanese Patent Publication No. 8l-60884) (b) A method of detecting the contamination of slag based on the light emitted by molten steel and slag, in other words, the temperature difference. (Japanese Unexamined Patent Publication No. 6O-125315) (C) A method for detecting slag contamination based on the pressure difference between molten steel and slag. (Japanese Patent Application Laid-Open No. 61-262454) All three methods mentioned above have their advantages and disadvantages, but methods (a) and (C) cause damage to the measuring device because the measuring device comes into contact with high-temperature molten steel or 70. Likely to occur (unfavorable).

The present invention detects 70 contaminations based on the method (b). However, JP-A-60-12531
The technology described in Publication No. 5 detects the light emitted by the molten steel flow discharged from a converter, so it targets objects with a high flow rate, such as molten steel flows, and has the disadvantage of lacking stability because the area of the object is small. there were.

(Means for Solving the Problems) The present invention provides a method for detecting and determining the inflow of slag into the ladle after completion of steel tapping in a converter. Then, the obtained image is input to the image processing 'A', the input image is decomposed into pixels, each l1tjJ8 is binarized by selecting a predetermined threshold value, the number of white pixels is determined, and the self-pixel is This is a method for determining completion of steel tapping in a converter, which is characterized by detecting the inflow of slag into the ladle based on a change in the number of slags.

In the present invention, when detecting the contamination of slag based on the difference in luminance of emitted light corresponding to the temperature difference between molten steel and slag, the surface of the ladle that receives the molten steel tapped from the converter is photographed with a television camera. Stable accuracy is achieved because the flow of slag into the ladle is detected from the image based on the difference in brightness between the light emitted by molten steel and slag.

(Function of the invention) As shown in Fig. 1, steel is tapped from a converter using molten ml after scouring.
This is done by tilting the converter (2) containing (1) and tapping the molten steel (1) into m (3). Converter (2
) is the slag (4) that exists above the molten steel (1).
After all of m (1) has flowed into the ladle (3), in other words, after the tapping has been completed, it flows into the ladle (3).

TV camera (5) is the i of molten steel (1) in ladle (3)
k Then (6) is photographed continuously. However, due to the installation space under the furnace, it is difficult to capture the surface (6) of molten steel (+) in the ladle (3) within the field of view of the television camera (5) immediately after the start of tapping. In addition, it is necessary to judge the completion of tapping when the molten steel (1) reaches approximately 374 mm in the ladle (3).
This is because of the above conditions. Therefore, the TV camera (5
) was installed on the side of the ladle (3), and when I remember that there was about 374 or more molten steel (Otori) in the ladle (3), the scene of molten steel (1) (6
). Also, TV camera (5)
is the position of the steel receiving cart (7) or the molten steel in the steel drawer (3) (
Due to the change in scene (6) in 1), the direction is automatically changed by the motor (8).

Before tapping, as shown in Figure 2 (a), the scene (+3) of molten steel (12) appeared black except for the falling part (position 5) of molten steel flow (14), but this is because tapping When completed, Figure 2 (
As shown in b), the slag (IB) spreads on the surface (13) of the molten steel (12), and the slag (16) that spreads on the surface (13) of the molten steel (12) becomes whitish. Utilizing this phenomenon, the present invention detects the inflow of slag into the ladle.

The image of the surface (6) of the molten steel (1) in the ladle (3) taken by the television camera (5) is input to the image processing device (9). The resolution of the IB image is, for example, 256×256 images, and in this case, the gradation of each image is resolved into 25e levels. At this time, if you examine the histogram of the image before the slag falls, you will see the one shown in Figure 3(a). When the slag spreads on the surface of the molten steel in the ladle due to the slag drop F, the areas with high concentration become whitish (visible to the naked eye) as shown in Fig. 3(b).

For example, a density value of 150 is selected as the predetermined threshold. 1
The number of pixels with a density value of 150 or more is white - the number of pixels, and the density value is 15
A binarization process is performed in which the number of pixels less than 0 is set to black - the number of pixels.

This binarization process is carried out during the middle stage of blowing, when no slag is mixed in.
This is applied to each pixel of a 258×25B image taken every second to obtain the white-pixel count. Furthermore, this white - number of pixels 5~
10II! ! Add l images and find the average value. This process of calculating the average value is performed in order to prevent errors due to variations. The average value serves as a reference value for the number of white pixels when determining whether the slag has fallen or not. This reference value +
The correction value is set as the slag fall determination threshold.

By manipulating the correction value, the determination timing can be manipulated.

As shown in FIG. 4, the number of white pixels that changes with time increases greatly due to the falling of slag. The numbers of white pixels before and after this were about 15,000 and about 30,000, respectively. In addition, the predetermined threshold value used for the binarization process here can be selected appropriately by calculating the histogram of the images during the slag fall and the song fall depending on the tapping conditions and steel type. can.

Further, by providing a neutral density filter or the like in the image input section, it is possible to select any value of α.

To detect falling slag, set the slag falling judgment threshold to, for example, 2000.
0 is determined when the number of white pixels exceeds the number of pixels, the completion of steel tapping is indicated to the converter control 'A' (10) in the form of a steel tapping completion signal, and the motor (11) is activated to control the converter (2). All you have to do is tilt the steel to complete tapping. The image processing device (3) performs the processing from the above-mentioned binarization processing of the incoming direction image to outputting the tapping completion signal.

(Example) An example of the present invention was applied to a 150T converter. Table 1 shows the number of personnel required to visually determine the completion of tapping.

Table 1 By carrying out the present invention, the work of determining the completion of tapping and giving a signal by looking at the slag is no longer necessary, and the process from tapping to slag can now be performed by three people.

In addition, the images captured by the television camera are sent to a remote monitor and can be used to monitor the tapping flow, level, etc. This example is an example in which the present invention is applied to converter steel tapping.
Needless to say, it can also be applied to metal smelting furnaces such as furnaces (furthermore, continuous casting).

It can also be applied to various steel manufacturing techniques such as ingot making.

Further, in this embodiment, tapping is completed by tilting the converter, but tapping may be completed by using a slag stopper or the like.

(Effects of the Invention) According to the present invention, completion of tapping is determined based on the difference in brightness between the light emitted by molten steel and slag, so it can be applied to a flow of molten steel with a high flow rate.

[Brief explanation of drawings]

Figure 1 is a diagram showing an embodiment of the present invention, Figure 2 is a diagram showing before (a) and after (b) the completion of tapping, and Figure 3 is (a) before the completion of tapping. FIG. 4 is a diagram showing the histogram of the yH degree value and the number of pixels shown in (b), and FIG. 4 is a diagram showing the change over time in the number of white pixels. (1)・・・・・・・・・ Molten steel (2
) ・・・・・・・・・ Converter (3)・・・・・・
・・・・ Tori m(4) ・・・・・・・・・
Noro (5)・・・・・・・・・ Television camera
（６）・・・・・・・・・ Yu (9)・・・・・・
... Image processing device (10) ...... Converter control device (I2) ...... Molten steel (1
3)・・・・・・・・・ Yu (14)
)・・・・・・・・・ +8 Steel style (15)・・・・・・
・・・・ Falling part (1B) ・・・・・・・・・
Figure 1 Figure 2 (a) (b) Figure 3 (α) (b) Figure 4 Questions

Claims (1)

[Claims] In the method of detecting and determining the inflow of slag into the ladle when the converter has been tapped, the surface of the molten steel in the ladle is photographed with a television camera, the obtained image is input to an image processing device, Decompose the input image into pixels, select a predetermined threshold value for each pixel, and binarize each pixel to determine the number of white pixels, and detect the inflow of slag into the ladle based on the change in the white pixel value. A method for determining completion of steel tapping in a converter.