JPH0288114A - Broken edge detecting and removing method for steel belt - Google Patents

Abstract

PURPOSE:To automatically perform optimum trimming without decreasing a line speed in detection, removal, etc., of a broken edge by removing from steel belt both side end parts with a side trimmer adjusted combining the side trimmer, broken edge detector and a broken edge removing means. CONSTITUTION:A side trimmer 5 removes a broken edge 4 in an edge part 2 in the width direction of a steel belt 1 by the initially preset value of a trimming margin 3, and detecting the broken edge remaining in the steel belt 1 by a speed/broken edge detector 6, a depth of the broken edge is classified by a rank, introducing a signal 10 to a computer 8. The computer 8, in accordance with the broken edge rank 10, judges notching for whether it is necessary or not and the depth of cut of the notching, when it is necessary, tracking is performed of the operation timing from a plate speed, obtained by a speed detector 17, and from a distance X, and when the broken edge part reaches a notcher 7, a start signal 12 is given, and the broken edge is removed by the depth of cut set in a cut depth signal 11. While by the depth of cut and a frequency accumulated in the computer 8, the trimmer 5 is automatically changed in trimming quantity through a signal 16, performing trimming suited for a broken edge condition.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for detecting and removing edge cracks in a steel strip, and more specifically,
In a continuous processing line for steel strips, after the edge cracks at both ends of the steel strip are sheared by a predetermined amount using a side trimmer, the remaining edge cracks in the steel strip are detected by the detector, and the edge cracks are removed. By changing the trimming allowance of the side trimmer based on information on the depth of the edge crack and its frequency, and removing the edge crack, we prevented the occurrence of breakage problems during threading and the next process. This relates to the detection and removal method.

For example, steel strips manufactured by conventional techniques such as hot rolling are shown in Fig. 2 (
As shown in a) and (b), the side end (edge) 2 of the steel strip 1
Ear cracks 4 may occur in some cases.

This steel strip 1 has a number of cracks 4! It is between 111 and 50, and if a deep (long) crack is passed through a rolling mill or an annealing furnace in that state, the crack will progress, and furthermore, the tension during rolling will cause damage during rolling. This can lead to problems such as the steel strip breaking during annealing.

This breakage trouble causes serious damage such as long line stoppages, equipment damage, and scrap generation, so it is necessary to prevent these problems.

For this reason, a method has conventionally been adopted in which the edge cracks are removed by trimming before the steel strip is passed through a rolling mill or an annealing furnace.

For example, as shown in Japanese Unexamined Patent Publication No. 51-94188, there is a bond in which edge cracks are sheared using a side trimmer before cold rolling a coiled steel strip.
There is a method of shaving at least once with a trimming allowance of ~10% to make the cut surface vertical and smooth.

However, with this method, it is not possible to accurately measure the depth of the edge crack, so the shearing process is performed using an empirical trimming allowance, and the shaving process is performed at least once, so the reduction rate of the steel strip is set at around 80%. Although it is possible to reduce the pressure and prevent the occurrence of ear cracks, the trimming cost becomes larger than necessary.

Therefore, the product walking speed is reduced, the scrap chopper blade wears out prematurely, and productivity is reduced due to replacement.

On the other hand, if the trimming allowance (edge cutting method) is reduced or no trimming is performed with the aim of improving the yield, edge cracks remain and the steel strip breaks when cold rolled.

On the other hand, if the trimming allowance is too large, scraps will increase and the yield will decrease. It is also possible to change the trimming distance of the side trimmer in accordance with the depth of the detected ear crack, but this requires a large-scale device, insufficient response, and a large amount of trimming.

In addition, it is difficult for an operator to visually check whether the steel strip has edges cracked at normal line speeds, and many things are overlooked. On the other hand, if you try to reliably determine whether or not the ears are cracked,
The line speed must be reduced, resulting in a significant reduction in production capacity.

As a method for solving such problems, for example, as shown in FIG. 3, an edge crack detector 6 is used to detect edge cracks that exist in the steel strip 1 when the steel strip is processed in a rolling mill or an annealing furnace. There is a method in which the computer 8 performs tracking processing and settings for the required ear-cutting method based on this information, and the side trimmer 5 performs the ear-cutting according to the size of the ear crack. However, although this method can detect edge cracks without reducing the line speed of the steel strip, it is difficult to perform appropriate trimming because shearing is performed with a fixed trimming allowance using only a side trimmer.

In order to form the above shape, as described above, in the conventional example, after shearing the edge cracks at the end of the steel strip passing on the line at a predetermined temperature using a side trimmer, the steel strip is further shaved to crack the edges of the steel strip. There have been proposals for methods and devices for removing edge cracks in steel strips, as well as methods for detecting edge cracks existing in steel strips using an edge crack detector, determining a trimming allowance based on this information, and removing edge cracks using a side trimmer. It's nothing more than that.

Therefore, no method has been proposed for removing the edge cracks at both ends of the steel strip with an appropriate amount of trimming.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned problems, and specifically, it is necessary to avoid taking a large trimming allowance for the edge cracks at both ends of the steel strip passing through the line (appropriate trimming allowance). The purpose of the present invention is to solve the problem that it is difficult to perform efficient trimming, and that research on such trimming methods has not been sufficiently conducted.

Means for Solving the Problems and Reducing Effects Namely, the present invention provides side edge cracks when removing edge cracks at both ends of a steel strip passing through a continuous processing line before the entry side of a rolling mill. After removing the steel strip by shearing it with a constant trimming allowance in the width direction using a trimmer, the remaining edge cracks in the steel strip are detected by an edge crack detector, the depth is measured, and this measurement value is compared with that on the line. According to the line speed of the steel strip to be plated, the edge crack removal means is driven to remove remaining edge cracks, and the side trimmer is trimmed based on information on the depth and frequency of edge cracks remaining in the steel plate. It is characterized by changing the range.

Hereinafter, the present invention will be described in detail with reference to the drawings.

In addition, FIG. 1 is an explanatory view showing an example of the apparatus used when implementing the present invention, FIG. 2(a) is a perspective view illustrating edge cracking of a steel strip, and FIG. FIG. 3 is an explanatory diagram of an example of a device used for detecting and removing edge cracks in a conventional steel strip.

Reference numeral 1 shown in FIG. 1 is a steel strip, 2 is an ear part (side end part), 3 is a trimming allowance (edge cut part), 4 is an ear crack, 5 is a side trimmer, 6 is a speed/re-crack detector, 7 is a notch, 8 is a computer, 10 is an ear crack rank signal, 11 is a notch cut rank signal, 12 is a start signal, 13 is a performance record, 15 is a line speed signal, 16 is a trimming width setting change signal, 11
18 is a speed detector, 18 is a crack sensor, and 19 is a removal trace.

First, for example, in the apparatus shown in FIG. 1, as shown in FIGS.
The hot-rolled steel strip 1 having ear cracks 4 at both ends of the steel strip 1 shown in b) is passed through the sheet, and a certain amount of trimming is performed by a side trimmer 5 before entering the cold rolling mill. Shearing is performed in step 3.

Next, the edge cracks 4 remaining in this steel strip are detected by a speed detector 17.
and fast rfJ with crack sensor 18,/re-crack detector 6
The measured values are ranked according to the ear crack depth as shown in Table 1 of the embodiment, and this ear crack rank signal 10 is input to the computer 8.

The computer 8 follows the crack rank signal 10,
Determine whether or not notching is necessary and the notching depth.

If notching is required, tracking of the ear crack is performed, a start signal 12 is given to the notch 7 at the position of the notch 7, and the ear crack is removed at the cutting depth set by the notch cut rank signal 11.

On the other hand, the computer 8 stores actual values of the depth and frequency of ear cracks processed by the notch 177 as described above, and based on this information, it is determined whether the trimming amount of the side trimmer 5 is appropriate or not. If it is determined that the trimming amount needs to be changed, the trimming amount is changed.

Next, each a position used in the present invention will be explained.

Ear crack detectors include eddy current flaw detection, ultrasonic flaw detection, and optical surface flaw detectors. There are commonly used means for removing edge cracks (for example, a flying method with a structure such as a set of two upper and lower disc-shaped rotary blades, a notch such as a one-sided rotary blade, cutting with a high-energy beam, and side trimming). The conveyance of the steel strip when removing ear cracks can be slowed down or stopped as necessary. The distance between the ear crack detector and the ear crack remover is not specified, but is determined by the line speed, the detection signal processing time, the dimensions of the ear crack remover, etc.

Example The present invention will be explained below with reference to Examples.

Example 1 Defects such as edge cracks and chips are removed from both ends of a hot-rolled steel strip using the apparatus shown in FIG. A cold rolling mill for steel strip 1 with a thickness of 1.5 to 4.0 mm (center (II 3 mm), width 600 to 1,600 mm <-center value of 1,200 mJ), which is passed in the rolling direction on a line with a line speed of 100 II/min. Before the entry side, there is a side trimmer 5, a speed/re-crack detector 6, and a notch 7 for detecting defects such as ear cracks.
Initial setting of trimming amount (i15~
Shear and remove with a constant width of 30 mm (center value 15 mm1).

Next, the edge crack remaining in the steel strip 1 is detected by the speed/re-crack detector, etc., and the edge crack depth is ranked into ranks as shown in Table 1, and the rank signals are recorded in Table 1. Determine whether or not notching is necessary and the depth of notching according to the ear crack rank in Table 1. If notching is necessary, track the operation timing from the temporary speed and distance When the start signal 12 is reached, the notch 7 receives a start signal 12.
At the same time, the edge cracks are removed at the notching depth set in the notching depth signal 11.

Further, the amount of trimming by the side trimmer is automatically changed based on the removal depth and removal work frequency stored in the computer 8. For example, if removal of rank 3 is performed more than 5 times per minute, the trimming amount is increased by 1011111. Or conversely, if the removal depth is within rank 1, it is 1 minute per minute.
If the ileum is not present, reduce the trimming fee by 5ffllT1. In this way, trimming is performed that is suitable for the condition of edge cracks in the raw coil.

<Effects of the Invention> As explained above, the present invention provides a side trimmer for removing edge cracks at both ends of a steel strip passing through a continuous processing line before the entry side of the rolling mill. After removing the steel strip by shearing it with a constant trimming allowance in the width direction, the remaining edge cracks in the steel strip are detected by an edge crack detector, the depth is measured, and this measurement value is used to calculate the thickness of the steel strip along the line. The edge crack removing means is driven according to the line speed of the steel strip to remove the remaining edge cracks, and the trimming amount of the side trimmer is adjusted based on information on the depth and frequency of edge cracks remaining in the steel plate. It is characterized by changing.

Therefore, the edge cracks at both ends of the steel strip are removed by combining a side trimmer, an edge crack detector, and an edge scraping removal means, and by adjusting the trimming amount of the side trimmer. It is possible to perform optimal trimming fully automatically without reducing the line speed in the processing process, which saves labor and reduces side trimming costs compared to conventional methods, improving productivity, walking speed, and Improvements in quality etc. can be achieved.

In addition, it is possible to highly reliably prevent or reduce plate breakage due to defects such as edge cracks in the steel strip, and it is also possible to significantly reduce the deterioration in the roll consumption rate and efficiency of rolling mills etc. resulting from such breakage. is possible.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a device used in carrying out the present invention, FIG. 2(a) is a perspective view illustrating edge cracking in a steel strip, FIG. 3(b) is a plan view thereof, and FIG. 1 is an explanatory diagram of an example of a device used for detecting and removing edge cracks in a conventional steel strip. Code 1... Steel strip 2... Ear part (side end) 3... Trimming allowance 4...
・Ear crack 5...Side trimmer 6...Speed/Sun crack detector 1...Notch 8...Computer 10...Ear crack Rank signal 11...Notch depth rank signal 12...
...Start signal 13...Achievements 15...
... Line speed signal 16 ... Trimming width setting change signal 11 ...
...Speed detector 18...Crack sensor 19
・・・・・・Removal marks

Claims (1)

[Claims] 1) When removing edge cracks at both ends of a steel strip passing through a continuous processing line before the entry side of a rolling mill, the edge cracks are removed in the width direction of the steel strip using a side trimmer. After shearing and removing the steel strip with a certain trimming allowance, the remaining edge cracks in the steel strip are detected by an edge crack detector, the depth is measured, and this measurement value is compared with the line of the steel strip to be passed on the above line. Depending on the speed,
The edge crack removal means is driven to remove the remaining edge cracks, and the trimming allowance of the side trimmer is changed based on information about the depth and frequency of the edge cracks remaining in the steel plate. A method for detecting and removing edge cracks in steel strips passing through a continuous processing line. 2) The method for detecting and removing edge cracks in a steel strip according to claim 1, wherein the edge crack removing means is a notcher.