JP5971229B2 - H-shaped steel cooling control method and H-shaped steel cooling control device - Google Patents

Description

  The present invention relates to a cooling control method for cooling a flange of an H-section steel and a cooling control apparatus for the H-section steel.

  Conventionally, there is a technique described in Patent Document 1, for example, as a shape control method by H-shaped steel flange cooling. This technology measures the temperature distribution in the flange width direction on the flange surface of the H-shaped steel before and after cooling the flange, and adjusts the nozzle height and nozzle angle of the flange water cooling device based on the temperature distribution in the flange width direction. . Here, the temperature center position in the flange width direction is calculated based on the temperature distribution in the flange width direction, and the nozzle height and nozzle angle are adjusted using this temperature center position.

JP 09-295003 A

However, in the technique described in Patent Document 1, the temperature center position in the flange width direction after completion of the flange cooling can be made to coincide with the flange width center position, but the temperature variation of the cooling water is completely taken into consideration. It has not been. Therefore, for example, when the temperature of the cooling water is significantly different in summer and winter, for example, the finishing temperature of the H-section steel varies, and the shape after cooling varies. In addition, after measuring the temperature distribution of the H-shaped steel in the flange width direction, the cooling condition for the next material is changed based on the temperature distribution. The cooling condition cannot be set.
Then, this invention makes it the subject to provide the cooling control method of H-section steel, and the cooling control apparatus of H-section steel which can reduce the dispersion | variation in the finishing temperature of H-section steel and the shape after cooling.

In order to solve the above problems, one aspect of the cooling control method for H-section steel according to the present invention is to cool the flange by injecting cooling water onto the flange surface of the H-section steel while conveying the H-section steel production line. A method for controlling the cooling of the H-section steel, in which the cooling water is injected so that the temperature change amount of the flange before and after cooling becomes a preset target temperature change amount according to the temperature of the cooling water. And adjusting at least one of the H-shaped steel passing speed, based on the flow rate at which the cooling water is injected, the H-shaped steel passing speed, and the temperature change of the flange before and after cooling. The relationship between the determined cooling rate coefficient and the temperature of the cooling water is calculated in advance, and based on the cooling rate coefficient corresponding to the actually measured temperature of the cooling water and the target temperature change amount, The amount of flange temperature change is the target temperature As a variation, and wherein the flow for injecting cooling water, and adjusting at least one of the passing material speed of the H-shaped steel.

  Thereby, the finishing temperature after cooling can be kept substantially constant regardless of the temperature of the cooling water. That is, when the temperature of the cooling water is extremely low compared to the summer, such as in the winter, cooling with the same cooling conditions as the summer (cooling water flow rate, H-section steel passing speed) Considering that the finished temperature is significantly lower than that in summer, it is possible to make adjustments such as reducing the flow rate of cooling water and increasing the material passing speed. Thus, the variation in the finished temperature after cooling due to the variation in the temperature of the cooling water can be reduced from the H-section steel that is initially passed.

Further, in the above, a cooling rate coefficient determined on the basis of a flow rate for injecting the cooling water, a material passing speed of the H-shaped steel, and a temperature change amount of the flange before and after cooling, and a temperature of the cooling water The relationship is calculated in advance, and based on the cooling rate coefficient corresponding to the measured temperature of the cooling water and the target temperature change amount, the temperature change amount of the flange before and after cooling becomes the target temperature change amount. , the flow rate for injecting the cooling water, and that to adjust the one of the passing material speed of the H-shaped steel.
As described above, the flow rate of the cooling water and the material passing speed are adjusted after the influence of the temperature of the cooling water on the cooling rate is obtained in advance. Therefore, it is possible to set an appropriate cooling condition such that the temperature change amount of the flange before and after cooling becomes the target temperature change amount.

  Furthermore, in the above, the target temperature change amount is the temperature of the flange before and after cooling when the flow rate for injecting the cooling water, the material passing speed of the H-section steel, and the temperature of the cooling water are standard values. The amount of change is preferred. Thereby, even when the temperature of the cooling water varies, the finished temperature after cooling can be kept at the finished temperature when cooled by the standard water temperature.

Moreover, one aspect | mode of the cooling control apparatus of the H-section steel which concerns on this invention is cooling the H-section steel which injects a cooling water on the flange surface of H-section steel while conveying an H-section steel manufacturing line, and cools the said flange A temperature measuring unit that measures the temperature of the cooling water, and a target temperature in which a temperature change amount of the flange before and after cooling is set in advance according to the temperature of the cooling water measured by the temperature measuring unit. A cooling condition adjusting unit that adjusts at least one of a flow rate for injecting the cooling water and a material passing speed of the H-shaped steel so as to change , and the cooling condition adjusting unit Preliminarily calculating the relationship between the cooling water temperature and the cooling rate coefficient determined based on the flow rate to be injected, the material passing speed of the H-shaped steel, and the temperature change amount of the flange before and after cooling, Cooling rate coefficient corresponding to measured temperature of cooling water Based on the target temperature change amount, at least one of a flow rate for injecting the cooling water and a material passing speed of the H-section steel so that the flange temperature change amount before and after cooling becomes the target temperature change amount. It is characterized by adjusting .
Thereby, the finishing temperature after cooling can be kept substantially constant regardless of the temperature of the cooling water. Thus, since the variation in the finishing temperature after cooling resulting from the variation in the temperature of the cooling water can be reduced, the variation in the shape of the H-shaped steel after cooling can be reduced.

  According to the present invention, the flow rate of the cooling water and the material passing speed of the H-shaped steel are adjusted according to the temperature of the cooling water sprayed to the flange surface of the H-shaped steel, so the temperature of the cooling water varies. Even in this case, it is possible to reduce variations in the finishing temperature and the shape after cooling from the material that is initially passed.

It is the schematic which shows a H-section steel rolling line. It is a figure which shows H-section steel. It is a figure explaining the outline | summary of a flange water cooling equipment. It is a figure which shows the example of a change of a temperature profile. This is an example of a defective flange shape. It is a figure which shows the measuring point of a cooling rate coefficient. It is a figure which shows the relationship between the temperature of the cooling water in the flange A point, and a cooling rate coefficient. It is a figure which shows the relationship between the temperature of the cooling water in the flange B point, and a cooling rate coefficient. It is a functional block diagram of the cooling control apparatus which performs cooling control processing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an H-section steel rolling line (conveyance line) to which the H-section steel cooling control method of this embodiment is applied.
As shown in FIG. 1, in the H-section steel rolling line 1, a heating furnace 2, a rough rolling mill 3, an intermediate rolling mill 4, a water cooling facility 5, and a finishing rolling mill 6 are sequentially arranged from the upstream side to the downstream side. doing.
The heating furnace 2 heats an H-shaped steel material having a flat cross section to a predetermined temperature, and the H-shaped steel material heat-treated in the heating furnace 2 is roughly shaped and rolled by the roughing mill 3. After the rough shaping, the H-shaped steel material is subjected to intermediate rolling by the intermediate rolling mill 4, then cooled by the water-cooling equipment 5, and finish-rolled by the finishing mill 6 to produce H-shaped steel.

As shown in FIG. 2, the H-section steel 10 includes a flange 11 and a web 12, and is conveyed on a table roll (not shown) of the H-section steel rolling line 1 in a posture in which the flange 11 is in the vertical direction. And the water cooling equipment 5 cools the H-section steel 10 by injecting cooling water from the outer surface of the flange 11 of the H-section steel 10.
That is, the water cooling facility 5 is composed of a first cooling zone 5 a and a second cooling zone 5 b, and nozzles for injecting cooling water are arranged opposite to each other across the H-section steel rolling line 1. Here, in the 1st cooling zone 5a, as shown to Fig.3 (a), a cooling water is injected from the nozzle 5c and the center part of the width direction of the flange 11 is spot-cooled. In the second cooling zone 5b, as shown in FIG. 3B, cooling water is injected from the nozzle 5d to cool the entire width of the flange 11.

In addition, thermometers 7a to 7d are arranged before and after the intermediate rolling mill 4 and before and after the finish rolling mill 6, respectively. Therefore, the thermometers 7b and 7c can measure the flange temperature before cooling by the water cooling facility 5 and the flange temperature after cooling.
Here, the temperature distribution in the flange width direction is determined by the flow rate at which the cooling water is injected, the H-beam passing speed, the temperature of the cooling water, and the like. That is, even if the cooling water flow rate and the material passing speed are set to the same condition, the temperature distribution in the flange width direction changes due to the influence of the cooling water temperature.

  FIG. 4 is a diagram illustrating an example of a temperature profile of the flange 11. As shown in FIG. 4, the temperature profile changes when there is a difference in the temperature of the cooling water, such as in summer and winter. Specifically, since the temperature of the cooling water in winter is significantly lower than that in summer, the flange temperature after cooling in winter will be Lower than the flange temperature. As described above, when the temperature profile changes, the temperature of the H-section steel in the finishing mill 6 (finished temperature of the water cooling equipment 5) varies, and the flange falls over as shown in FIG. As shown in b), a shape defect such as inward flange fall may occur.

The inventors adjust the flow rate of jetting the cooling water according to the temperature of the cooling water and the passing speed of the H-shaped steel material that is the material to be cooled, so that the finished temperature of the H-shaped steel and the shape after cooling are adjusted. It has been found that the variation of can be reduced.
First, in order to evaluate the influence of the coolant temperature, the present inventors investigated the following cooling rate coefficient results for each cross section of the H-section steel.
Cooling rate coefficient = (temperature before cooling−temperature after cooling) / flow rate of cooling water × feeding speed ………… (1)
Here, the cooling water temperature is changed within a predetermined range (for example, 24 ° C. to 33 ° C.) in a state where the flow rate of the cooling water and the material passing speed of the material to be cooled are set to standard values, respectively, and the flange before cooling is performed. The cooling rate coefficient was determined by measuring the temperature and the flange temperature after cooling.
The standard flow rate of the cooling water in the first cooling zone 5a is 2100 [L / min], the standard flow rate of the cooling water in the second cooling zone 5b is 1160 [L / min], and the standard material passing speed is 3.0 [m. / S]. Thus, in this H-section steel rolling line 1, the first cooling zone 5a standard flow rate is set relatively large with respect to the standard flow rate of the second cooling zone 5b.

7 and 8 show the results of obtaining the cooling rate coefficients for the points A and B of the flange 11 shown in FIG. 6 under the above conditions. Comparing FIG. 7 and FIG. 8, it can be seen that the cooling rate coefficient at the point B of the flange 11 is greatly affected by the temperature change of the cooling water.
Therefore, in this embodiment, particularly in the first cooling zone 5a, using the relationship between the temperature of the cooling water and the cooling rate coefficient shown in FIG. A cooling control process for appropriately setting the cooling condition is executed.

FIG. 9 is a functional block diagram of a cooling control device that executes cooling control processing. The cooling control device 20 is composed of, for example, a microcomputer having a CPU, a memory, and the like, and includes a cooling rate coefficient storage unit 21, a target temperature change setting unit 22, a cooling rate coefficient calculation unit 23, a flow rate setting unit 24, And a material passing speed setting unit 25.
The cooling rate coefficient storage unit 21 stores a relational expression indicating the relationship between the cooling water temperature and the cooling rate coefficient obtained in advance as shown in FIG.

  The target temperature change setting unit 22 uses, as a target temperature change amount, a temperature change amount before and after cooling of the material to be cooled under standard cooling conditions (standard flow rate, standard material passing speed, standard cooling water temperature (32 ° C. in this case)). Set. Here, first, the cooling rate coefficient at the standard temperature (32 ° C.) is calculated with reference to the relational expression stored in the cooling rate coefficient storage unit 21. Next, based on the calculated cooling rate coefficient at the standard temperature, standard flow rate, and standard material passing speed, the amount of change in temperature before and after cooling of the material to be cooled based on the above equation (1) (temperature before cooling−cooling) After temperature) is calculated. This is set as the target temperature change amount.

The cooling rate coefficient calculation unit 23 inputs the temperature of the cooling water measured by the thermometer 5A installed in the water cooling facility 5, and based on the measured temperature value, the relational expression stored in the cooling rate coefficient storage unit 21 is obtained. The cooling rate coefficient corresponding to the actually measured temperature value is calculated with reference to FIG.
The flow rate setting unit 24 sets the flow rate of the cooling water so that the temperature change amount of the flange 11 before and after cooling when cooled with the actually measured cooling water becomes the target temperature change amount set by the target temperature change setting unit 22. . Specifically, based on the target temperature change amount set by the target temperature change setting unit 22, the cooling rate coefficient calculated by the cooling rate coefficient calculating unit 23, and the standard material passing speed, the above equation (1) is also obtained. And the flow rate of the cooling water is calculated.
That is, the flow rate of the cooling water calculated here is the flange 11 when the temperature change amount before and after the cooling of the flange 11 is cooled under the standard cooling condition when cooling is performed with the passing speed set to the standard passing speed. The flow rate is equal to the amount of temperature change before and after cooling.

Then, the flow rate setting unit 24 outputs the calculated flow rate of the cooling water to the flow rate control unit 5B of the water cooling facility 5 as a flow rate command value. Thereby, the flow volume of the cooling water injected from the water cooling equipment 5 is adjusted according to the flow rate command value.
Here, instead of the flow rate setting unit 24 setting the flow rate of the cooling water, the material passing rate setting unit 25 may set the material passing rate. In this case, the material passing speed setting unit 25 passes the material so that the temperature change amount of the flange 11 before and after cooling when cooled with the measured cooling water becomes the target temperature change amount set by the target temperature change setting unit 22. Set the speed. Specifically, based on the above equation (1) based on the target temperature change amount set by the target temperature change setting unit 22, the cooling rate coefficient calculated by the cooling rate coefficient calculating unit 23, and the standard flow rate. Calculate the threading speed.
That is, the material passing speed calculated here is the temperature of the flange 11 when the cooling water is cooled under the standard cooling condition when the cooling water is cooled by setting the flow rate of the cooling water to the standard flow rate. The material passing speed is equal to the amount of change.

Then, the material passing speed setting unit 25 outputs the calculated material passing speed to the material passing speed control unit 1A of the H-section steel rolling line 1 as the material passing speed command value. Thereby, the threading speed of the H-section steel rolling line 1 is adjusted according to the threading speed command value.
As described above, in this embodiment, after determining the influence of the cooling water temperature on the cooling rate in advance, the flow rate for injecting the cooling water and the material passing speed of the material to be cooled are set according to the measurement result of the cooling water temperature. To do.
The thermometer 5A corresponds to the temperature measurement unit, and the cooling rate coefficient calculation unit 23, the flow rate setting unit 24, and the material passing rate setting unit 25 correspond to the cooling condition adjustment unit.

(Example)
Hereinafter, the effect of the present invention will be specifically described with reference to examples.
Here, in the H-section steel rolling line 1 shown in FIG. 1, H-700 × 200 × 9 × 19 H-section steel is water-cooled, and the actual temperatures after cooling at the points A and B of the flange 11 are investigated. .
As Comparative Example 1, the flow rate of cooling water and the material passing speed are standard values (flow rate: 2100 [L / min], material passing speed: 3.0 [m / s]), and the cooling water temperature is 32 ° C. The temperature was measured.
As Comparative Example 2, the flow rate of cooling water and the material passing speed are standard values (flow rate: 2100 [L / min], material passing speed: 3.0 [m / s]), and the temperature of the cooling water is 33 ° C. The temperature was measured.
As Comparative Example 3, the coolant flow rate and material passing speed are standard values (flow rate: 2100 [L / min], material passing speed: 3.0 [m / s]), and the cooling water temperature is 25 ° C. The temperature was measured.

  Further, as Example 1, the material passing speed is a standard value (3.0 [m / s]), the temperature of the cooling water is 25 ° C., and the flow rate of the cooling water in the first cooling zone 5a is appropriate by the cooling control process. The actual temperature was measured by adjusting the flow rate. That is, the flow rate of cooling water so that the amount of temperature change before and after cooling when cooled with 25 ° C. cooling water is equal to the amount of temperature change before and after cooling when cooled under standard cooling conditions (cooling water 32 ° C.). Was set lower than the standard flow rate. Here, the flow rate of the cooling water was set to 1800 [L / min].

Furthermore, as Example 2, the flow rate of the cooling water is a standard value (2100 [L / min]), the temperature of the cooling water is 24 ° C., and the actual temperature is measured by adjusting the material passing speed to an appropriate speed by the cooling control process. did. That is, the material passing speed is standardized so that the amount of temperature change before and after cooling when cooled with 24 ° C. cooling water is equal to the amount of temperature change before and after cooling under standard cooling conditions (cooling water 32 ° C.). Set faster than speed. Here, the material passing speed was set to 3.4 [m / s].
The target temperature after cooling and the actual temperature were respectively compared by the above methods. The results are shown in Table 1.

  As can be seen from Table 1, when the temperature of the cooling water is at or near the standard temperature, the actual temperature relative to the target temperature after cooling is maintained even if the cooling water flow rate and the material passing speed remain at the standard values. It was confirmed that the error was small (Comparative Example 1 and Comparative Example 2). However, when the temperature of the cooling water is significantly lower than the standard temperature, it can be seen that the error of the actual temperature with respect to the target temperature after cooling becomes large if the flow rate of the cooling water and the material passing speed remain at the standard values ( Comparative Example 3). In Comparative Example 3, the actual temperature at the flange B point is significantly below -40 ° C with respect to the target temperature.

On the other hand, in Example 1 and Example 2, even if the temperature of the cooling water is significantly lower than the standard temperature, the flow rate of the cooling water and the material passing speed are adjusted to appropriate values. Thus, it was confirmed that the error between the target temperature and the actual temperature can be kept within about 11 ° C.
In this way, the finished temperature after cooling can be kept substantially constant regardless of the temperature of the cooling water. In other words, even when the temperature of the cooling water is extremely low compared to the summer, such as in the winter, by adjusting the flow rate of the cooling water to be smaller than that of the summer or to increase the material passing speed, Variations in the finished temperature after cooling caused by variations in the temperature of the cooling water can be reduced. Therefore, variation in the shape of the H-shaped steel after cooling can be reduced.

Prior to the cooling control process, the cooling rate coefficient determined based on the flow rate of jetting the cooling water, the H-beam passing speed, and the temperature change amount of the flange 11 before and after cooling, and the temperature of the cooling water The relationship is obtained in advance. Then, based on the cooling rate coefficient corresponding to the measured temperature of the cooling water and the target temperature change amount, the flow rate of the cooling water and H so that the temperature change amount of the flange 11 before and after cooling becomes the target temperature change amount Adjust the threading speed of the shape steel.
As described above, the flow rate of the cooling water and the material passing speed are adjusted after obtaining the influence of the cooling water temperature on the cooling rate in advance, so that the temperature change amount of the flange before and after cooling becomes the target temperature change amount. It is possible to set appropriate and appropriate cooling conditions.

  By the way, as a cooling control of the H-section steel, after measuring the temperature distribution in the flange width direction of the H-section steel after actually cooling, a method of changing the cooling condition for the next material based on the temperature distribution However, in this case, it is not possible to set appropriate cooling conditions for the H-section steel that is initially passed. Therefore, the temperature accuracy of the first rolled material is insufficient and shape defects are likely to occur.

On the other hand, in this embodiment, since the flow rate and material passing speed which inject a cooling water are adjusted with the measurement performance of the temperature of a cooling water, material can be manufactured at the temperature as a target from the 1st rolling.
As described above, since the finish temperature of the H-section steel and the variation in the shape after cooling due to the variation in the coolant temperature can be reduced, an H-section steel having a good flange shape can be obtained.

(Modification)
In the above embodiment, based on the cooling rate coefficient corresponding to the measured temperature of the cooling water and the target temperature change amount, the flow rate and flow of the cooling water are set so that the temperature change amount of the flange before and after cooling becomes the target temperature change amount. When adjusting the material speed, one of the cooling water flow rate and the material passing speed is set to the standard value and the other is adjusted. However, both the cooling water flow rate and the material passing speed should be adjusted. You can also.

  DESCRIPTION OF SYMBOLS 1 ... H-section steel rolling line, 2 ... Heating furnace, 3 ... Rough rolling mill, 4 ... Intermediate rolling mill, 5 ... Water cooling equipment, 5a ... 1st cooling zone, 5b ... 2nd cooling zone, 5c, 5d ... Nozzle, 6 ... Finishing mill, 7a to 7d ... Thermometer, 10 ... H-section steel, 11 ... Flange, 12 ... Web

Claims (3)

A cooling control method for H-section steel that cools the flange by injecting cooling water onto the flange surface of the H-section steel on a conveyance line,
According to the temperature of the cooling water, at least the flow rate of injecting the cooling water and the material passing speed of the H-shaped steel so that the temperature change amount of the flange before and after cooling becomes a preset target temperature change amount. One to adjust ,
The relationship between the cooling water temperature and the cooling rate coefficient determined based on the flow rate for injecting the cooling water, the material passing speed of the H-shaped steel, and the temperature change amount of the flange before and after cooling is calculated in advance. Leave
Based on the cooling rate coefficient corresponding to the measured temperature of the cooling water and the target temperature change amount, the flow rate at which the cooling water is injected so that the flange temperature change amount before and after cooling becomes the target temperature change amount, And the cooling control method of H-section steel characterized by adjusting at least one of the material passing speed of said H-section steel . The target temperature change amount is a temperature change amount of the flange before and after cooling when the flow rate for injecting the cooling water, the material passing speed of the H-shaped steel, and the temperature of the cooling water are standard values. The method for controlling cooling of an H-section steel according to claim 1 . A cooling control device for H-section steel that cools the flange by injecting cooling water onto the flange surface of the H-section steel on a conveyance line,
A temperature measuring unit for measuring the temperature of the cooling water;
According to the temperature of the cooling water measured by the temperature measuring unit, the flow rate for injecting the cooling water so that the temperature change amount of the flange before and after cooling becomes a preset target temperature change amount, and the H shape A cooling condition adjusting unit for adjusting at least one of the steel passing speed ,
The cooling condition adjustment unit includes a cooling rate coefficient determined based on a flow rate for injecting the cooling water, a material passing speed of the H-shaped steel, and a temperature change amount of the flange before and after cooling, and a temperature of the cooling water. Is calculated in advance,
Based on the cooling rate coefficient corresponding to the measured temperature of the cooling water and the target temperature change amount, the flow rate at which the cooling water is injected so that the flange temperature change amount before and after cooling becomes the target temperature change amount, And at least one of the H-shaped steel passing speeds is adjusted .

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