JPH02212015A - End cutting method in hot billet rolling - 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 (Field of Industrial Application) The present invention relates to a method for cutting edges in hot steel rolling, which involves cutting and rolling edges to a certain length to prevent edge cracks and misrolls. .

(Prior Art) In rolling hot steel, in order to prevent cracks and misrolls at the ends, the ends are cut to a certain length before rolling. In this cutting, if the cutting length is too short, it will not be possible to sufficiently cut off the defective end portions, and flaws such as cracks will remain in the rolled product. Furthermore, if the cutting length is not long, the yield will be poor, so it is very important to cut the ends to the optimum length.

Conventionally, this method of cutting the end uses an optical detector that detects the passage of the hot steel to be rolled, detects the passage of the tip of the hot steel, detects the passage of the tip at a certain point, and then After passing a certain distance set by an operator or the like, a cutting instruction is issued, and the tip of the hot steel is cut off.

(Problems to be Solved by the Invention) However, in the case of such a conventional method, if the shape of the end portion is different, the cutting is performed at a position shifted from the optimum cutting position, resulting in variation in the cutting length. For example, as shown in Fig. 4 (a) to (c), the cutting length l is determined by the detection position S with respect to the optimum length, so it is appropriate for material A, but for material B. It is too short, and in the case of material C, it is too long.Also, there are delays and variations in the electrical and mechanical systems from the time the cutting position is determined until the actual cutting. In this respect, there was also a problem with the accuracy of the cutting length at the end.

In view of such conventional problems, the present invention cuts at a position where the area of the cut end is constant, measures the end area after cutting, and feeds it back to the cutting command. The purpose of this invention is to provide a method for cutting edges in hot steel rolling, which can improve product quality accuracy and yield by eliminating variations in the area of cut edges.

(Means for Solving the Problems) In order to solve the above problems, the end cutting method in hot steel rolling of the present invention sequentially measures the end area of the hot rolled steel material to be cut from the edge, This measured area is compared with a preset cutting area, and when the areas match, a cutting command is output, and the end area after cutting is measured, and this area is compared with the end area when the cutting command is output. are compared, and a correction value based on the area difference is feedbanked to the cutting command output.

(Function) By using the method described above, the present invention does not measure the cut length of the cut end as in the conventional method, but measures a certain cut area from the edge, and the measured area becomes the set area. If they match, a disconnection command is output and the disconnection is performed. Then, in order to eliminate the time lag between the cutting command and the actual cutting, the end area after cutting is measured and compared with the end area at the time of the cutting command, and the correction value based on the difference is calculated as above. By feeding back the cutting command output, the subsequent cutting area can be made closer to the set value.

(Example) An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of an area measuring method in an image processing apparatus.

In FIG. 1, l is an ITV camera that images the end of the heat-controlled rolled material 2 and inputs the image signal to the image processing device 3. The image processing device 3 uses an image binarization means 4 to measure the end area of the rolled material 2 and determine the cutting position.
and area measuring means 5, and processes the image to obtain the area.

Here, the image processing method will be explained based on FIG. 2.

First, the captured image is binarized at a certain level, and the measurement target area of the image is divided vertically and horizontally as shown in Fig. 2. For each divided dot, an image 2' of the rolled material is generated. The number of dots in the part of the image 2° (the shaded part in the figure) is added up, and the product of the sum of the dots and the unit area of one dot is calculated. The edge area can be obtained. As the rolled material 2 is transferred, the edge area measured within the surface to be measured in FIG. The cut end area is compared with the set end area set in advance by the cutting area setting means 7 based on the size and the like. The comparator 6 outputs a cutting command when the measured end area matches the set end area.

Reference numeral 8 denotes a cutting pulse calculation unit, which calculates () based on the setting pulse set in advance by the pulse setting means 9 and the correction value output of the correction calculation unit 15, which will be described later, in response to the cutting command from the comparator 6.
A cutting timing setting pulse is calculated and output to the next pulse comparator 10.

This pulse comparator 10 receives a set pulse outputted from the cutting pulse calculator 8 and a moving pulse sent from a pulse generator 11 which generates a pulse output by detecting the rotation of the rolling roll 16 transporting the rolled material 2. When the set pulse and the integrated value of the moving pulse from the pulse generator 11 match, a cutting instruction is output to the next cutter 12. Here, the setting by the pulse setting means 9 is made by the pulse generator 11 from the time when the cutting command is output from the comparator 6 through image processing by the ITV camera l until the cutting position of the rolled material 2 reaches the cutter I2. It is set in advance in accordance with the number of movement pulses to be generated.

The cut end 2a of the rolled material 2 cut by the cutter 12 is inspected by the second ITV camera 13, and its cut area is measured by the image processing device 14.
This image processing is performed in the same way as the processing in the image processing device 3 described above. Information on the actual cutting edge area is input to the correction calculator 15, where it is compared with the measured edge area of the image processing device 3 at the time when the comparator 6 outputs the cutting command, and the difference in area is calculated. It is output to the pulse calculator 8 as a correction value for the pulse calculator 8. This correction value is calculated based on the mechanical and electrical power of the transportation equipment for the rolled material 2, the cutting machine 12, etc., from the cutting command from the comparator 6 until the cutting machine 12 cuts the end of the rolled material 2 in response to the cutting instruction from the comparator 10. target drift,
This is to absorb variations, which can be reflected in the subsequent end cutting of the rolled material 2, and can prevent time lags caused by them.

Here, a comparison will be made between a conventional example and a specific example of end cutting according to the present invention based on FIG. In this example, the rolled material 2 is steel billet size: 160 am, type: free-cutting steel (SU
M), the size after rough rolling is 55 mm, and the ideal cut end length is 250 nu++. The variations in the cut ends in the conventional method resulted as shown in FIG. 3(a). On the other hand, in the case of the method of the present invention, under the same conditions,
As shown in the same figure (b), it can be seen that the variation has been considerably improved.

(Effects of the Invention) As described above, the present invention measures a certain cutting area from the edge of a rolled material and outputs a cutting command when the measured edge area matches a set area. The area of the cut end is also measured and compared with the end area at the time of the cutting command, and the correction value based on the difference is fed back to the cutting command output. Since the cutting point is determined by measuring the cutting point, there is no variation in the cut end due to the shape of the end, and defects such as cracks can be suppressed and the yield can be improved. Furthermore, since the end area is actually measured after cutting and the correction value is fed back, errors caused by delays and variations in electrical and mechanical control systems can be absorbed, making it possible to provide higher quality products with no time lag. It is an effective invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the method of the present invention, and FIG.
The figure is an explanatory diagram of the area measurement method in the same image processing device, Figures 3 (a) and (b) are characteristic diagrams of the dispersion of cutting results by the conventional method and the method of the present invention, and Figures 4 (a) to (c) are It is an explanatory view showing an example of cut length by the shape of the cut edge part in a conventional example. 1.13 is an ITV camera, 2 is a rolled material, 2a is a cut end, 3.14 is an image processing device, 6 and 1O are comparators, 7 is a cutting area setting means, I2 is a cutting machine, and 15 is a correction calculator . Fig. 3 (a) Bō (b) Kō Fig. 4 (4n (jν)

Claims (1)

[Claims] (1) Measure the end area of the hot rolled steel material to be cut sequentially starting from the edge, compare this measured area with a preset cutting area, and when both areas match, output a cutting command. An edge in hot steel rolling characterized by measuring an end area after cutting, comparing the area with an end area when a cutting command is output, and feeding back a correction value based on the area difference to the cutting command output. Section cutting method.