JPH0747415A - Cooling control method for steel sheet - Google Patents

Abstract

PURPOSE:To provide the cooling control method for producing a steel sheet of a high quality. CONSTITUTION:A steel sheet 2 is decelerated and a processing in the subsequent preduction control is discriminated from a processing before it is decelerated, and the processing is decelerated by a speed predicting device 14 and while predicting the subsequent speed, a temperature prediction is executed by using this speed, and in accordance with this predicted temperature, a water pouring pattern of a cooling device 3 is determined, and the water pouring quantity of cooling control is controlled. In such a way, the same control is not executed to overall length, and with respect to a steel sheet after deceleration is started, the control is executed delicately so as to be different from its previous control, therefore, a steel sheet of a high quality can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel sheet cooling control method for cooling a hot rolled steel sheet by a hot rolling runout table.

[0002]

2. Description of the Related Art In a hot rolling facility, controlling a coiling temperature of a steel sheet between a finishing step and a coiling step is important for determining a material, and as disclosed in, for example, JP-A-3-198905. , The result of this comparison by comparing the target value of the coiling temperature for the tip of the rolled material rolled while being accelerated and the temperature detected by the thermometer in the coiler of the rolled material that has already been rolled Based on the above, the target temperature at the tip of the self-rolling material used when cooling the self-rolling material is calculated.

FIG. 4 is a block diagram showing a conventional cooling control method for steel sheets. In the figure, 1 is a finish rolling mill having a plurality of stages, 2 is a steel sheet rolled by a finish rolling mill 1, and 3 is a steel sheet 2. It is a cooling device such as a hot rolling run-out table that cools water with water. The cooling device 3 is divided into, for example, ten or more cooling zones (banks) in the longitudinal direction (feeding direction) of the steel plate 2, and by independently opening and closing the water injection nozzle for each bank to control the water injection amount, It is configured to control the temperature of the steel plate 2 to a predetermined target temperature.

[0004] 4 is a winder for winding the cooled steel plate 2, 5
Is a speed detector that interlocks with the finish rolling mill 1 to detect the speed of the entrance side of the steel plate 2, 6 is a speed detector that interlocks with the winder 4 to detect the speed of the exit side of the steel plate 2, and 7 is a steel plate 2 is a plate thickness gauge for detecting the thickness, 8 is a thermometer for detecting the inlet side temperature of the steel plate 2,
Reference numeral 9 is a thermometer for detecting the actual temperature on the outgoing side of the steel plate 2.

Reference numeral 10 denotes a water injection pattern determining section for determining the water injection pattern of each cooling bank based on the detected temperature, speed, plate thickness, etc., and 11 controls the water injection amount of the cooling device 3 in accordance with the determined water injection pattern. It is a water injection control unit.

Reference numeral 12 is a correction calculation unit for calculating an average value of the difference between the actual temperature detected by the thermometer 9 and the target temperature, and 13 is learning for correcting the target value for the next rolling on the basis of the average value. It is a calculation unit.

Next, the operation will be described. The steel plate 2 rolled by the finish rolling mill 1 passes through the cooling device 3 and the winder 4
Will be wound up in sequence. In this case, steel plate 2 from the start of rolling
Is accelerated and reaches a constant speed, so that a part of the length from the front end of the steel plate 2 is an acceleration part where the speed is accelerated.

The temperature measured by the thermometer 8 on the inlet side of the cooling device 3, the speed measured by the speed detectors 5 and 6, and the plate thickness gauge 7
The plate thickness measured in 3 is input to the water injection pattern determination unit 10 to determine the optimum water injection pattern for each cooling bank. The determined water injection pattern is given to the water injection control unit 11, and the water injection control unit 11 controls the water injection of each bank in accordance with the above water injection pattern.

On the other hand, in the correction calculation unit 12, the measured coiling temperature at each position of the acceleration portion from the tip of the steel plate 2 detected by the thermometer 9 is stored, and this data is used to measure the acceleration portion. The average value of the difference between the target value and the actual value is calculated, and this result is given to the learning calculation unit 13. The learning calculation unit 13 determines a target value of the winding temperature for the above-described accelerated portion of the steel sheet to be rolled next time, gives this target temperature correction value to the water injection pattern determination unit 10, and the water injection pattern determination unit 10 accelerates from the tip. For each position of the portion, the water injection pattern is calculated based on a target value different from the winding temperature target value after the length of the acceleration portion, and water injection control of each bank is performed.

When the rolling is completed and the tail end of the steel sheet 2 passes through a predetermined rolling mill of the finishing rolling mills 1 having a plurality of stages, the steel sheet 2
Is started to be decelerated and is wound up to the tail end by the winder 4 while being decelerated. Therefore, a deceleration portion having a certain length from the tail end of the steel plate 2 to the tip direction occurs.

[0011]

Since the conventional cooling control method for a steel sheet is constructed as described above, the temperature control of the acceleration portion and the constant speed portion thereafter is controlled to the target temperature and the corrected target temperature. However, it was difficult to control the deceleration portion to the target temperature.

FIG. 5 shows the actual temperature in the longitudinal direction of the steel plate 2. As shown in the figure, the cooling device 3 is started at the start of deceleration.
It can be seen that the temperature of the part cooled by is much lower than the target temperature. This occurs because the water injection control is performed after the water injection pattern is determined based on the speed and temperature detected after the deceleration is started, so that the actual water injection is delayed. As described above, the conventional cooling control method has a problem that the quality of the steel sheet deteriorates due to the decrease in control accuracy in the deceleration portion.

The present invention has been made to solve the above problems, and provides a steel plate cooling control method capable of improving the control accuracy for the deceleration portion and producing a high quality steel plate. With the goal.

[0014]

According to a first aspect of the present invention, there is provided a steel plate cooling control method, which predicts when a decelerating portion passes through a cooling device, detects it, and starts detecting it when the detection is made. The temperature is predicted by using the predicted speed instead of the detected speed that has been used until then, and the water injection amount is controlled based on the predicted temperature.

In the steel plate cooling control method according to the second aspect of the present invention, the average value of the difference between the actual temperature of the deceleration portion and the target temperature is obtained and stored.

In the steel plate cooling control method according to the third aspect of the present invention, the actual cooling temperature of the deceleration portion is used to correct the cooling capacity estimated value used for temperature prediction, and the corrected value is stored. .

[0017]

In the method for controlling the cooling of the steel sheet according to the first aspect of the present invention, at the same time that the deceleration portion starts to be cooled, cooling is performed for each of the steel sheets by an appropriate amount of water injection.

In the steel plate cooling control method according to the second aspect of the present invention, the average value of the difference between the stored actual temperature and the target temperature is reflected in the temperature prediction of the cooling control at the next rolling, so that the deceleration portion is controlled. Appropriate water injection is performed.

In the steel plate cooling control method according to the third aspect of the present invention, the corrected cooling capacity estimated value is reflected in the temperature prediction of the cooling control during the next rolling, so that the water is appropriately injected into the deceleration portion.

[0020]

【Example】

Example 1. An embodiment of the invention of claim 1 will be described below with reference to the drawings. In FIG. 1, parts corresponding to those in FIG. 4 are assigned the same reference numerals and explanations thereof are omitted. In FIG. 1, 14
Is a speed prediction device that detects the deceleration portion of the steel plate 2 according to the detection of the speed detector 5 and outputs a speed prediction value based on a predetermined deceleration rate based on this detection, and 15 is the speed detector 5 and the plate. This is a temperature prediction device that predicts the temperature by a calculation formula using a predetermined cooling capacity estimated value using the detection values of the thickness gauge 7 and the thermometers 8 and 9.

Next, the operation will be described. The temperature predicting device 15 predicts the temperature of the steel plate 2 based on the detected inlet temperature, the actual temperature, the detected speed, the plate thickness, etc., and the water injection pattern determination unit 10 sets the predicted temperature as the target temperature and responds to it. Determine watering pattern. The water injection control unit 11 controls the water injection of the cooling device 3 according to the determined water injection pattern.

On the other hand, the tail end of the steel sheet 2 is decelerated after passing through the finish rolling mill 1 where deceleration starts, and thereafter, the tail end passes through the final finishing rolling mill 1 and is wound up by the winder 4. In contrast, the speed detectors 5 and 6 are the final finishing rolling mill 1
It is possible to measure the steel plate length from the front end to the tail end of the steel plate 2 after the steel plate 2 has passed through. The speed prediction device 14 measures this steel plate length moment by moment, and can estimate in advance the steel plate portion whose tail end is the target of the deceleration range before the start of deceleration, that is, the deceleration portion,
When this portion passes through the cooling device 3, the speed prediction device 14 operates and outputs the predicted speed value to the temperature prediction device 15.

The temperature predicting device 15 uses the speed predicted value instead of the detected speed, predicts the temperature based on this, the temperature, the plate thickness, etc., and the water injection pattern is determined according to the predicted temperature. It will be.

FIG. 2 shows an embodiment of the invention of claim 2 and parts corresponding to those of FIG. 1 are designated by the same reference numerals. In FIG. 2, reference numeral 16 denotes a temperature prediction correction device that corrects and stores the temperature prediction value based on the temperature prediction value of the temperature prediction device 15 and the actual temperature.

Next, the operation will be described. The temperature prediction correction device 16 uses the actual temperature detected by the thermometer 9 so that the tail end of the steel plate 2 exits the deceleration start finish rolling mill 1 and is decelerated thereafter, and the tail end exits the final finishing mill 2 and the winder. For the deceleration portion, the temperature is added to the temperature predicted by the temperature predicting device 15 or the ratio between the actual temperature and the predicted temperature is stored as the predicted correction temperature in the longitudinal direction of the deceleration portion until it is wound up by 4.

The value of the predicted correction temperature is reflected in the temperature prediction of the temperature predicting device 15 for the deceleration portion of the steel sheet next time, and the water injection pattern determination unit 10 determines the water injection pattern.

FIG. 3 shows an embodiment of the invention of claim 3, and the portions corresponding to those of FIG. 1 are designated by the same reference numerals. In FIG. 3, reference numeral 17 is a cooling capacity correction device that corrects the cooling capacity estimated value used for the calculation of the temperature prediction device 15 based on the actual temperature.

Next, the operation will be described. The cooling capacity correction device 17 uses the actual temperature detected by the thermometer 9 to correct the cooling capacity estimated value used for the predicted temperature calculation by the temperature prediction device 15 for the deceleration portion, and the deceleration portion in the longitudinal direction. The corrected value is stored in memory, the value is reflected in the temperature predicting device 15 for the decelerating portion of the steel sheet after the next rolling, and the water injection pattern determination unit 10 determines the water injection pattern.

[0029]

As described above, according to the invention of claim 1,
Since the prediction speed is used for prediction when the temperature of the deceleration portion is predicted, high-precision cooling control for the deceleration portion is reliably performed for each steel sheet, and there is an effect that the quality of the steel sheet can be improved.

According to the second aspect of the present invention, since the average value of the difference between the actual temperature and the target temperature for the deceleration portion is obtained and stored, this is stored. Therefore, the temperature prediction is performed using the stored value. By performing the above, it is possible to perform highly accurate cooling control for the deceleration portion, and it is possible to obtain a high quality steel plate.

Further, according to the third aspect of the invention, the cooling capacity estimated value is corrected and stored based on the actual temperature for the deceleration portion, so that the temperature prediction is performed by using the stored value. High-precision cooling control can be performed on the deceleration portion, and high-quality steel plate can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a cooling control method of a steel sheet according to an embodiment of the invention of claim 1.

FIG. 2 is a configuration diagram showing a cooling control method for a steel sheet according to an embodiment of the invention of claim 2;

FIG. 3 is a configuration diagram showing a steel plate cooling control method according to an embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional steel plate cooling control method.

FIG. 5 is a characteristic diagram showing an actual example of a conventional winding temperature.

[Explanation of symbols]

 1 Finishing rolling mill 2 Steel plate 3 Cooling device 4 Winding machine

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[Procedure amendment]

[Submission date] December 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

FIG. 5 shows the actual temperature in the longitudinal direction of the steel plate 2. As shown in the figure, the cooling device 3 is started at the start of deceleration.
It can be seen that the temperature of the part cooled by is much lower than the target temperature. This is because the water injection control is performed after the water injection pattern is determined based on the speed and temperature detected after deceleration is started, so the water injection pattern for the detected speed
The actual speed of the steel sheet is much slower,
A supercooling phenomenon occurs due to a speed error . As described above, the conventional cooling control method has a problem that the quality of the steel sheet deteriorates due to the decrease in control accuracy in the deceleration portion.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Next, the operation will be described. The temperature prediction correction device 16 uses the actual temperature detected by the thermometer 9 so that the tail end of the steel plate 2 exits the deceleration start finish rolling mill 1 and is decelerated thereafter, and the tail end exits the final finishing mill 2 and the winder. For the deceleration portion, the temperature predicted by the temperature prediction device 15 is added or the ratio of the actual temperature and the predicted temperature is multiplied until the winding speed is reduced to 4.
The calculated correction temperature is stored in the longitudinal direction of the deceleration portion as a predicted correction temperature.

Claims (3)

[Claims] 1. When the steel sheet exiting the finish rolling mill is water-cooled by a cooling device and then cooled by a winder, the temperature of the steel sheet before cooling and the actual temperature after cooling are detected and the detected speed. And a temperature prediction step of predicting the temperature based on the plate thickness, a control step of controlling the water injection amount of the cooling device according to the temperature predicted in the temperature prediction step, the finish rolling mill tail end of the steel plate Of the deceleration step of decelerating the speed of the steel sheet at a predetermined deceleration rate from the time when is passed, and a deceleration portion where the deceleration step is performed on the steel sheet is predicted, and this deceleration portion passes through the cooling device. A detection step of detecting, and a temperature prediction step of predicting the temperature using a speed predicted in accordance with the deceleration rate instead of the detected temperature used by the temperature prediction step in accordance with the detection of the detection step, and A method for controlling cooling of a steel sheet, comprising: 2. When the steel sheet exiting the finish rolling mill is cooled by pouring water with a cooling device and then wound by a winder, the temperature of the steel sheet before cooling and the actual temperature after cooling are detected speeds. And a temperature prediction step of predicting the temperature based on the plate thickness, a control step of controlling the water injection amount of the cooling device according to the temperature predicted in the temperature prediction step, the finish rolling mill tail end of the steel plate The deceleration step of decelerating the speed of the steel sheet at a predetermined deceleration rate from when the passage of the A method for controlling cooling of a steel sheet, comprising: 3. The temperature before cooling of the steel sheet and the actual temperature after cooling when the steel sheet exiting the finishing rolling mill is water-cooled by a cooling device and cooled and then wound by a winder, the detected speed. A temperature prediction step of predicting the temperature using a predetermined cooling capacity estimated value based on the plate thickness and the plate thickness, a control step of controlling the water injection amount of the cooling device according to the temperature predicted in the temperature prediction step, and Based on the deceleration step of decelerating the speed of the steel sheet at a predetermined deceleration rate from the time when the tail end of the steel sheet passes through the finish rolling mill, and the actual temperature in the deceleration portion where the deceleration step is performed on the steel sheet. A steel sheet cooling control method comprising: a correction storage step of correcting the cooling capacity estimated value and storing the corrected value.