JPH06306492A - Method for trucking strip in strip continuous heat treatment line - Google Patents

Abstract

PURPOSE:To improve a trucking precision of a strip in a heat treatment furnace zone and further, to prevent the deterioration of quality near the changing point of manufacturing condition of welding part, etc., and the lowering of passing stability of the strip. CONSTITUTION:One or more punched hole detectors for detecting the punched hole bored on the strip are arranged in the heat treatment furnace zone, and by measuring the extension/shrinkage of the strip in the heat treatment furnace zone, a correcting rat at the time of calculating the conveying quantity of the strips from the number of revolutions of roll measured by a revolution counter fitted to the roll for carrying the strip, can precisely be obtd. By using the punched hole detecting signals from the punched hole detectors, the carrying quantity of the strip at each punched hole detector position is corrected, and by using this correcting rate to correct the carrying quantity of the strip, the trucking precision of the strip in the heat treatment furnace zone is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip tracking method in a continuous heat treatment line of a strip having a heat treatment furnace, such as a continuous annealing line and a hot dip galvanizing line, in which a strip is continuously heat-treated.

[0002]

2. Description of the Related Art Conventionally, tracking of a strip in a continuous strip processing line, such as a continuous annealing line, has been performed by measuring the number of revolutions of the roll and the roll measured by a tachometer attached to a strip conveying roll such as a bridle roll. It is basically performed by recognizing the position of a specific point of the strip, such as the tip of the strip, in the line by measuring the amount of transport of the strip by multiplying it by the diameter.

As an auxiliary means for this purpose, for example, for the purpose of detecting and correcting a tracking error caused by a slip between the bridle roll and the strip, a roll diameter measurement error, etc., the strip is punched at the time of strip welding or the like. A punch hole detection device for punching holes and detecting punch holes punched is installed in the strip continuous processing line, and the punch hole detection signal from these devices corrects the transport amount of the strip measured by the tachometer. This is also generally done in the past.

A plurality of such punch hole detecting devices are usually installed in a continuous processing line. For example, in a continuous annealing line, an inlet / outlet of an inlet side looper, an inlet / outlet of an outlet side looper, and an inlet / outlet of a skin pass mill. It is generally installed at the exit.

[0005]

However, particularly in the heat treatment furnace zone, a large temperature change of the strip (for example, in a continuous annealing line, after heating the strip from room temperature to about 800 ° C., it is cooled to room temperature again). There is a problem that the tracking accuracy of the strip deteriorates due to the expansion and contraction of the strip accompanying the above, and the elongation of the strip caused by applying a high tension to the high temperature soft strip.

In order to solve this problem, a punch hole detecting device may be installed in the heat treatment furnace zone. However, the punch hole is not necessarily punched at a specific point of the strip to be tracked. In this case, there is a problem that the tracking accuracy of the strip is deteriorated because the amount of transport of the strip cannot be corrected by the punch hole detection signal from the punch hole detection device.

As a result of these problems, the timing of various setting changes in the heat treatment furnace zone performed on the basis of tracking is largely deviated, the quality near the manufacturing condition change point such as the welded portion is deteriorated, and the strip running There was a problem that stability was impaired.

The present invention has been made in view of the problems of the prior art as described above, and its main purpose is to improve the tracking accuracy of the strip in the heat treatment furnace zone and, by extension, to improve the welded portion. This is to prevent quality deterioration near the manufacturing condition change point and deterioration of strip running stability.

[0009]

SUMMARY OF THE INVENTION According to the present invention, the above object is to detect punched holes in a strip in a continuous heat treatment line of a strip having a heat treatment furnace through which the strip is continuously threaded. One or a plurality of punch hole detecting devices are installed in the heat treatment furnace zone, and a punch hole detecting signal from the punch hole detecting device is used to correct the strip transport amount at each punch hole detecting device position. The correction amount is weighed, and from the ratio of the correction amount to the equipment length, the correction factor is calculated when calculating the strip transport amount from the roll rotation speed measured by the tachometer attached to the strip transport roll. When calculating the transport amount of the strip from the rotation speed of the roll measured by the tachometer attached to the transport roll, the correction amount is used to calculate the transport amount of the strip. It is achieved by providing a strip tracking method strip continuous heat treatment line, characterized in that positively.

[0010]

In this way, one or a plurality of punch hole detecting devices for detecting punch holes punched in the strip are installed in the heat treatment furnace zone, and the expansion and contraction of the strip in the heat treatment furnace zone is measured, whereby the strip is conveyed. It is possible to accurately obtain the correction factor when calculating the transport amount of the strip from the number of roll rotations measured by the tachometer attached to the rolls for each roll. By correcting the strip transport amount at the position of the punch hole detecting device and correcting the strip transport amount using the correction rate, the strip tracking accuracy in the heat treatment furnace zone can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the drawings.

FIG. 2 shows a schematic structure of a continuous annealing line for strips to which the present invention is applied. A pay-off reel 1 and a pay-off reel 2 are installed at this line entrance. These payoff reels 1, 2 to strip 3
Is continuously supplied, and the strip is continuously supplied to the cleaning device 5 by welding the end of the previous strip to the end of the latter strip by the welding machine 4 so as to overlap each other. There is.

The strip 3 supplied to the cleaning device 5 is cleaned, the supply amount of the strip 3 is adjusted by the entrance looper device 6, and then the strip 3 is sent into a process for performing an annealing process. Then, after passing through the heating furnace 7, the soaking furnace 8, the primary cooling furnace 9, the overaging furnace 10, and the secondary cooling furnace 11, the strip 3 annealed according to a predetermined heat cycle is fed out by the exit side looper device 12. The amount is adjusted and then sent to the skin pass mill 13.

After being temper-rolled by the skin pass mill 13, the strip is disposed on either side of the take-up shear 14 before and after the strip 3 in the conveying direction, and either one of the tension reels 15 and 16 as a take-up reel is provided. It is wound up as a coil.

In each heat treatment furnace (7 to 11), a large number of hearth rolls 17 are provided for applying appropriate tension to the strip 3 so that the strip 3 can run continuously.
12, heat treatment furnace zone (7-11) and skin pass mill 13
A bridle roll 18 is provided in front of and behind the.

As a strip tracking device, a tachometer 1 attached to a bridle roll 18 is used.
9, a punch hole detection device 20, a punch hole punching device 21, and a strip tracking recognition device 22.

Further, the strip tracking recognition device 2
2 instructs the setting control device 23 of the setting change timing based on the strip tracking, and the setting control device 2
3 changes various setting values based on the instruction.

Next, according to the flow chart shown in FIG.
The operating procedure of this embodiment will be described.

Strip tracking involves strip 3
It is started when the tip of is welded by the welder 4 (steps 1 and 2). Strip tracking recognition device 22
Is the bridle roll 18 obtained from the tachometer 19.
The amount of increase in the number of rotations of the strip 3 is read (step 3), the amount of increase in the number of rotations is multiplied by the roll outer peripheral length and the correction factor to calculate the amount of increase in the conveyance of the strip 3 on each bridle roll 18 (step 4). Among them, the increased amount of conveyance on the target bridle roll 18 is added to the accumulated amount of conveyance of the strip (step 5).

As described above, since the correction rate based on the actual measurement is multiplied, the integrated value of the transport amount can be correctly recognized, and the strip tracking in the heat treatment furnace zone can be accurately performed.

A punch hole detecting device 2 is used to detect a punch hole made in the strip 3 by using the punch hole punching device 21 during welding or the like.
When 1 is detected (step 6), the distance from the welding machine to the punch hole detector is compared with the integrated value of the strip transport amount calculated from the number of rotations of the bridle roll (steps 7 and 8). If the error is larger than the range, it is recognized as an erroneous signal and the carry amount of the strip 3 is not corrected (step 9). If the error is within the range, the strip carry amount integrated value is changed from the welding machine to the punch hole detector. By adjusting the distance to the strip 3 to correct the transport amount of the strip 3 (step 10), and at the same time, from the error amount of the strip transport amount integrated value, the number of revolutions of the roll measured by the tachometer attached to the strip transport roll. Then, a correction factor for calculating the strip transport amount is obtained (step 11).

Here, the expansion and contraction of the strip due to the temperature change of the strip, which is the main cause of the deterioration of the tracking accuracy in the heat treatment furnace zone, and the elongation of the strip caused by applying a high tension to the high temperature soft strip, , The strip thickness and width, the heat treatment temperature, the tension in the heat treatment furnace zone, and the strip material are correlated, so the correction factor is described as a function of these factors, and the data obtained from multiple strips are Use the correction factor calculated from these factors to calculate the correlation coefficient, or calculate the correction factor for each operating condition category that includes these factors, and adjust the correction factor according to the operating condition category of each strip. If is used, the tracking accuracy can be further improved. Further, if the correction factor obtained here is learned online, the correction factor can be obtained more accurately while following changes in the situation such as wear of the strip transport roll.

The strip tracking recognition device 22 includes
The above process is performed periodically, and when the tail end of the strip is cut by the outlet shear 14, the strip tracking of the strip is completed (step 12).

The punch hole detecting device 21 provided in the heat treatment furnace zone is provided between the soaking furnace 8 and the primary cooling furnace 9 in which the temperature of the strip greatly changes and the set value needs to be changed at an accurate timing. It is installed, for example, between the overaging furnace 10 and the secondary cooling furnace 11.

[0025]

As is apparent from the above description, according to the strip tracking method of the strip continuous heat treatment line of the present invention, the heat treatment furnace zone is detected by the punch hole detection signal from the punch hole detection device installed in the heat treatment furnace zone. The tracking accuracy of the strip in the heat treatment furnace zone can be improved by correcting the strip transport amount in the heat treatment zone, and the correction rate based on the actual measurement is used, and the heat treatment is performed even for the tracking point where no punch hole is drilled. The tracking accuracy of the strip in the furnace zone can be improved.

As a result, various settings can be changed in the heat treatment furnace zone at an accurate timing, and it is possible to prevent quality deterioration near the manufacturing condition change point such as a welded portion and deterioration of strip running stability. become able to. From the above, the effect of the present invention is great.

[Brief description of drawings]

FIG. 1 is a flow chart showing an operating procedure in a preferred embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a continuous annealing line to which the present invention is applied.

[Explanation of reference signs] 1, 2: Payoff reel 3: Strip 4: Welding machine 5: Cleaning device 6: Entry side looper device 7: Heating furnace 8: Soaking furnace 9: Primary cooling furnace 10: Overaging furnace 11: Two Next cooling furnace 12: Delivery side looper device 13: Skin pass mill 14: Delivery side shear 15, 16: Tension reel 17: Hearth roll 18: Bridle roll 19: Rotation speed meter 20: Punch hole detection device 21: Punch hole punching device 22 : Strip tracking recognition device 23: Setting control device

Claims (1)

[Claims] 1. A strip tracking method for a continuous heat treatment line for a strip having a heat treatment furnace in which strips are continuously passed, wherein a punch hole detection device for detecting punch holes punched in the strip is provided in a heat treatment furnace zone. One or a plurality of them are installed in each of the punch hole detecting devices, the punch hole detection signal from the punch hole detecting device is used to correct the strip transport amount at each punch hole detecting device position, and the correction amount is measured. And the equipment length ratio, the correction factor is calculated when calculating the strip transport amount from the roll rotation speed measured by the tachometer attached to the strip transport roll, and the tachometer attached to the strip transport roll is calculated. When calculating the transport amount of the strip from the rotation speed of the roll measured by, the correction factor is used to correct the transport amount of the strip. Strip tracking method strip continuous heat treatment line to.