JPH07122102B2 - Heat buckle prevention method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing heat buckle in a continuous strip annealing line.

[0002]

2. Description of the Related Art In a continuous annealing line for heat-treating a strip in a predetermined heat cycle, if the strip speed, tension, and furnace temperature are not properly balanced, the strip will buckle in the width direction. A so-called heat buckle phenomenon due to wrinkles along the plate direction may occur. If this heat buckle occurs, measures must be taken to immediately suppress it, but it is necessary to reduce the tension and the strip speed.
It is known that this can be suppressed by taking measures such as reducing the furnace temperature. Therefore, conventionally, a device that detects the deformation of the strip surface by processing the image of the laser beam applied to the strip surface, detects the occurrence and extent of heat buckle from this signal and issues an alarm, and recognizes this alarm The heat buckle was dealt with by appropriately changing the operating conditions based on the operator's judgment.

[0003]

However, in order to properly carry out the above-mentioned measures, extremely high skill is required, and it is easy to intervene due to an adverse effect caused by an individual error or an operation error, and in some cases, productivity is lowered. There was the inconvenience of having to invite.

The present invention has been devised in order to eliminate such inconveniences of the prior art, and its main purpose is to further speed up the transition to a normal state when a heat buckle occurs, It is to provide a heat buckle prevention method capable of increasing productivity.

[0005]

According to the present invention, such an object is obtained in advance based on the relationship between various parameters relating to operating conditions such as strip speed, tension and furnace temperature and the degree of heat buckle. The set table is stored in the computing machine, and the table is searched based on the evaluation points obtained from the signal indicating the degree of heat buckle of the heat buckle detection device,
This is achieved by providing a heat buckle prevention method characterized in that the change control of various operating conditions is controlled by the output corresponding to the optimum treatment amount obtained in this way.

[0006]

According to such a structure, the optimum change margin of the operating conditions according to the degree of the heat buckle is automatically selected, and appropriate measures are automatically taken.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic structure of continuous annealing equipment to which the present invention is applied. The strip 2 is continuously supplied from the pay-off reel 1 installed at the line entrance, and the end of the previous strip is welded to the end of the subsequent strip by the welding connection device 3 so as to overlap each other, and then to the cleaning device 4. After being cleaned, the amount of supply is adjusted by the inlet looper device 5, and then fed into a furnace for heat treatment. Then, the strip 2 heat-treated according to a predetermined heat cycle through the heating furnace 6, the soaking furnace 7, the primary cooling furnace 8, the overaging furnace 9, and the secondary cooling furnace 10 has a delivery amount adjusted by a delivery side looper device 11. After being processed, it is sent to the skin pass mill 12. After being temper-rolled by the skin pass mill 12, the inspection and conditioning device 13 divides or removes the defective portion, and the processed strip 2 is wound on the tension reel 14. Further, in each furnace, a large number of hearth rolls 15 for applying an appropriate tension to the strip 2 to run the strip 2 are provided.

FIG. 2 shows the structure of the heat buckle prevention device. Laser light is emitted from the projector 21 in the width direction of the strip 2 toward a position adjacent to the portion wound around the hearth roll 15, and an image captured by the CCD camera 22 is processed by the processing device 23. The deformation of the strip surface is detected from the signal. From this detected value, the degree of deformation of the strip surface, that is, the ratio of the width and height of the heat buckle portion is calculated by the calculator 24, and the evaluation point (height / width) for expressing the degree of the heat buckle is calculated. .. Then, the setting table of each change allowance of speed, tension and furnace temperature stored in the calculator 24 in advance is searched, and the optimum value of each change allowance (speed ΔV, tension ΔT, furnace temperature Δt) corresponding to the heat buckle evaluation point is searched. Is read and given to the controller 25. The control device 25 adjusts the tension and strip speed by issuing a change command of the drive torque and the rotation speed to the drive motor 26 of the hearth roll, and adjusts the furnace temperature by controlling the heat quantity of the burner 27. . In this way, when a heat buckle occurs, various operating conditions are automatically changed so as to suppress it.

The table of change allowance is set based on the empirical know-how of a skilled person, and an example thereof is shown in FIG. 3, which is set according to the plate temperature, plate width, plate thickness, etc. It is recommended to prepare multiple types and carry them differently according to the board specifications.

[0011]

As described above, according to the present invention, since the optimum change control of various operating conditions is automatically performed according to the degree of heat buckle, it is always constant regardless of the operator's intuition and experience. Measures against the heat buckle are promptly taken on the basis of the above judgment criteria, and it becomes possible to realize a quick shift to the normal operation state. Therefore, it is possible to suppress the occurrence of defective portions in the continuous annealing equipment and to exert a great effect in increasing the productivity.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of a continuous annealing facility to which the present invention is applied.

FIG. 2 is a schematic configuration diagram of a heat buckle prevention device.

FIG. 3 is an example of a table showing a relationship between heat buckle evaluation points and each change allowance.

[Explanation of symbols]

 1 Payoff reel 2 Strip 3 Welding connection device 4 Cleaning device 5 Entry side looper device 6 Heating furnace 7 Soaking furnace 8 Primary cooling furnace 9 Overaging furnace 10 Secondary cooling furnace 11 Exit side looper device 12 Skin pass mill 13 Inspection and refining device 14 Tension Reel 15 Hearth Roll 21 Projector 22 CCD Camera 23 Processing Device 24 Computing Unit 25 Control Device 26 Drive Motor 27 Burner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Sasaki Kimitsu Ichibanchi, Kimitsu City, Chiba Shin-Nippon Steel Co., Ltd. Inside the Kimitsu Works (56) References JP-A-1-259131 (JP, A) JP-A 2-200760 (JP, A) JP 59-229218 (JP, A) JP 63-86820 (JP, A) JP 63-62825 (JP, A) JP2-16374 (JP, B2)

Claims (1)

[Claims] 1. A method for preventing a heat buckle that occurs in a continuous strip annealing line, which relates to the relation between various parameters relating to various operating conditions such as strip running speed, tension, furnace temperature and the degree of the heat buckle. Based on the evaluation point obtained from the signal indicating the degree of heat buckle of the heat buckle detection device, the table set in advance based on the table is searched, and the optimum treatment amount obtained by this is searched. A method for preventing heat buckle, characterized in that the control for changing the operating conditions is performed by a corresponding output.