JP3233165B2 - Shape control method for H-section steel - 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 of controlling the shape of an H-section steel, and more particularly to a method of controlling the shape of an H-section steel flange just above a finishing mill such as a universal finishing mill. The present invention relates to a shape control method for preventing warpage.

[0002]

2. Description of the Related Art In general, rolling of an H-section steel is performed so that its cross section becomes H-shaped. However, when the H-section steel exiting a finish rolling mill is transported by a transport table or the like. In addition, due to the heat retaining effect of the transfer table and the like, the temperature distribution of the cross-sectional shape of the H-section steel 1 becomes non-uniform as shown in FIGS. A temperature difference is generated between the lower part 3 and the H-shaped steel, as shown in FIG. 7, due to the temperature difference.

Conventionally, in order to reduce such warpage of the H-section steel, a flange cooling method has been used in a H-section steel production line in which cooling water is blown onto a flange of the H-section steel to cool the H-section steel. ing. In this conventional flange cooling method for an H-section steel, the cooling water density distribution in the flange width direction is often symmetrical with respect to the center of the flange width in many cases, and in rare cases, the temperature difference between the upper and lower portions of the flange is reduced. In view of this, a cooling method that reduces the temperature difference is adopted. That is, Japanese Patent Application Laid-Open Nos. 52-142613, 63-248501, and 1-1160
No. 33 discloses a method for reducing the residual stress by adjusting the cooling water amount and by spraying a pattern.

Japanese Unexamined Patent Publication (Kokai) No. 63-186827 discloses a method of cooling by giving a reverse warp at a high temperature, and Japanese Unexamined Patent Publication (Kokai) No. 1-205033 discloses a method of mechanically restraining the warp. Is disclosed.

[0005]

However, Japanese Patent Application Laid-Open Nos. Sho 52-142613 and Sho 63-24850 describe above.
In the method of controlling the shape of an H-section steel disclosed in Japanese Unexamined Patent Application Publication No. Hei. There is an unsolved problem that the temperature distribution cannot be dynamically responded to, and if the symmetry of the temperature distribution in the flange direction is lost for these reasons, warpage occurs in the cooling process.

Further, the methods disclosed in JP-A-63-186827 and JP-A-1-205033 are both unstable controls. In particular, equipment is required for mechanically restraining the apparatus. However, there is an unsolved problem that it is not suitable for a factory that attempts to produce a large number of shaped steels with high efficiency. In view of the above, the present invention has been made in view of the unsolved problem of the above-described conventional example. It is an object of the present invention to provide a method for controlling the shape of an H-section steel, which can prevent the occurrence of warpage by making the upper and lower portions non-uniform.

[0007]

In order to achieve the above object, a method of controlling the shape of an H-section steel according to the present invention is characterized in that cooling water is supplied to a flange of an H-section steel positioned such that the flange is vertical. In the method of controlling the shape of an H-section steel by controlling the warpage of the H-section steel by spraying, the flange temperature of the H-section steel is measured at a plurality of positions in the flange width direction, and the measured temperature is used to measure the flange temperature.
Lunge upper and lower temperature moment sum M _u, down M _L
Calculated from Equations (1) and (2), respectively.
Flange upper portion and lower temperatures moment sum M _u was, M _L
The height position of the cooling water injection nozzle is adjusted according to the difference between the two . Where B: flange width T _U (x), _TL (x): temperature distribution function x: distance from the center of the flange

[0008]

According to the present invention, the flange temperature of the H-section steel is determined by
Measure at several locations in the width direction of the lunge and use this measured temperature
Flange upper portion and lower temperatures moment sum M _u, the M _L
Calculated and calculated temperature temperature of upper and lower flanges
Cement sum M _u, the height of the cooling water injection nozzle in accordance with the difference of M _L
Adjust the position so that any type of H-beam
Control the shape of H-beams easily and accurately
it can.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic system diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an H-shaped steel that is conveyed by a conveyance table after exiting a finishing mill, 2 is an upper flange of the H-shaped steel 1, and 3 is a lower flange of the H-shaped steel 1. Reference numerals 4a and 4b denote temperature sensors for measuring the temperature distribution in the width direction of the upper flange 2. The measured temperatures are supplied to the analog multiplexer 5. Reference numerals 4c and 4d denote temperature sensors for measuring the temperature distribution in the width direction of the lower flange 3, and the measured temperatures are also supplied to the analog multiplexer 5. Further, a selection signal from the control unit 7 described later is supplied to the analog multiplexer 5, and one measured temperature signal selected from a number of input signals of the analog multiplexer 5 is supplied to the A / D converter 6,
The measured temperature analog-digital converted by the A / D converter 6 is supplied to the control unit 7. When reading the supplied measured temperature signal, the control unit 7 reads the analog multiplexer 5
Is updated, and the measured temperature signal which is sequentially converted from analog to digital is read.

The control unit 7 comprises a CPU, a memory, and an input / output interface. The control unit 7 reads the measured temperatures of the upper flange 2 and the lower flange 3 measured by the temperature sensors 4a to 4d. The sum of the temperature moments is calculated, and a control signal for controlling the height position of the cooling water injection nozzle 9 disposed upstream of the H-section steel 1 in the rolling direction is transmitted to the water cooling device 8 based on the calculated sum of the temperature moments. Output to

The water cooling device 8 determines the height position of the cooling water injection nozzle 9 based on a position control signal from the control unit 7. The cooling water injection nozzle 9 injects cooling water from a predetermined height perpendicular to the flange of the H-section steel 1. next,
The operation of the above embodiment will be described with reference to the flowchart of FIG. The process in FIG. 4 is executed at predetermined time intervals by a timer interrupt.

That is, in step S1, the temperature distribution of the upper flange 2 and the lower flange 3 measured by the temperature sensors 4a to 4d is read via the analog multiplexer 5, and in step S2, the temperature moment of the upper flange 2 and the lower flange 3 is read. Calculate the sum. Here, the concept of the temperature moment was used for the following reason.

The warpage of the H-section steel is caused by an imbalance in bending moment based on the residual stresses above and below the flange, and the residual stress is caused by the amount of thermal shrinkage of each part of the flange. There is a proportional relationship within the range. Therefore, the bending moment was replaced with the concept of temperature moment, and this was used as a control index.

Assuming that the residual stress generated in the cooling process is proportional to the finishing temperature of each part of the flange, the warpage is obtained by integrating (temperature of each part) × (distance from the center of the flange) in the flange width direction. It is determined by the upper and lower difference of the sum of the temperature moments. That is, the product of the distance (arm length) from the center in the flange width direction to the temperature measurement point (arm length) and the measured temperature value is defined as the temperature moment. Ask for.

Here, the equation for calculating the sum of the temperature moments of the upper flange is as follows: the flange width is B, and the temperature distribution function is T _U (x).
Then, it is expressed by the following equation (1). Here, X is the distance from the center of the flange, and the equation for calculating the sum of the temperature moments of the lower flange is represented by the following equation (2), where B is the flange width and T _L (x) is the temperature distribution function.

[0016] However, X: distance from the center of the flange. The relationship above is shown in the temperature distribution schematic diagram of FIG.

[0017] Then, in step S3, comparing the temperature moment sum M _L temperatures moment sum M _U and a lower flange of the upper flange. Step when the M _U> M _L S4
Migrated to, when the M _U ≦ M _L proceeds to step S5. Then, the height of the cooling water injection nozzle is controlled based on the vertical difference of the sum of the temperature moments. In step S4, a position control signal for moving the cooling water injection nozzle upward by ΔH _U is output to the water cooling device 8, and the processing in FIG. 4 ends.

Here, the nozzle movement amount ΔH _U is expressed by the following (3)
It is expressed by an equation. _{ΔH U = L · (M U} -M L) ............ (3) where, L: the proportional coefficient step S5, outputs a position control signal for moving the cooling water jetting nozzles downward by [Delta] H _L to the water-cooling unit 8 And FIG.
Is completed.

Here, the nozzle movement amount ΔH_LIs (4)
It is expressed by an equation. ΔH_L= L · (M_L-M_U) (4) where L is a proportionality coefficient. Therefore, the system is now powered on and the processing shown in FIG.
First, in step S1, each of the flanges is processed.
The temperature of the part is read, and then the upper part is read in step S2.
Temperature moment sum M of flange_UAnd lower flange temperature
Moment sum M _LIs based on the above equations (1) and (2)
Is calculated. Then, in step S3, the upper
Temperature moment sum M_UAnd lower flange temperature mode
Mento M_LAre compared. Now, M_U> M_LIn
If the
Move to step S4. In step S4, the cooling water injection
Raise the height position of the chisel 9 by the amount represented by the above formula (3).
Is output to the water cooling device 8 and the processing of FIG.
You.

Meanwhile, assuming that a M _U ≦ M _L, to reduce the temperature of the flange bottom, the process proceeds to step S5. In step S5, a command to lower the height position of the cooling water injection nozzle 9 by the amount represented by the above equation (4) is output to the water cooling device 8, and the processing in FIG. Note that FIG.
The horizontal axis represents the equivalent temperature vertical difference obtained by dividing the vertical difference of the sum of temperature moments, which is the control index in the above embodiment, by half the dimension of the flange width to obtain a temperature dimension.
The graph plots the amount of warpage with respect to the equivalent temperature difference between a large number of H-section steels with the amount of warpage as the vertical axis. From this figure, it can be seen that there is a correlation between the vertical difference of the sum of temperature moments and the amount of warpage, and the warpage of the H-section steel can be controlled by the vertical difference of the sum of temperature moments.

In practice, an H-beam with less warpage is obtained for each water-cooled zone by controlling the height of the cooling water injection nozzle for the next rolled material based on the flange temperature distribution on the exit side of the zone. I was able to. In the above embodiment, the case where the number of the temperature sensors is two at the upper part and the lower part of the flange has been described. However, the more the number of the temperature sensors is, the more accurate the temperature distribution in the flange width direction becomes. Can be measured.

In the above embodiment, a plurality of temperature sensors are arranged in the width direction of the flange.
However, the present invention is not limited to this. The temperature sensor may be moved in the flange width direction to measure the temperature of each part, and the temperature pattern in the flange width direction may be measured by a width thermometer using a radiation thermometer. You may.

[0023]

As described above, according to the method of controlling the shape of the H-section steel according to the present invention, the flange temperature of the H-section steel is controlled by the flange temperature.
Measure at several locations in the width direction of the lunge and use this measured temperature
Flange upper portion and lower temperatures moment sum M _u, the M _L
Calculated and calculated temperature temperature of upper and lower flanges
Cement sum M _u, the height of the cooling water injection nozzle in accordance with the difference of M _L
Adjust the position so that any type of H-beam
Control the shape of H-beams easily and accurately
This has the effect of preventing warpage of the H-section steel.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of an embodiment.

FIG. 2 is a schematic diagram of a temperature distribution of upper and lower flanges of an H-section steel of an example.

FIG. 3 is a diagram showing a correlation between a flange upper and lower equivalent temperature difference of an H-section steel and an amount of warpage.

FIG. 4 is a flowchart of the embodiment.

FIG. 5 is a general characteristic diagram of a temperature distribution in a flange width direction immediately after finish rolling of an H-section steel.

FIG. 6 is a sectional view of an H-section steel.

FIG. 7 is a diagram illustrating an example of a warp deformation mode of an H-section steel.

[Explanation of symbols]

 Reference Signs List 1 H-section steel 2 Upper flange 3 Lower flange 4a, 4b, 4c, 4d Temperature sensor 5 Analog multiplexer 6 D / A converter 7 Control unit 8 Water cooling device 9 Cooling water injection nozzle

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C21D 9/00 102 B21B 45/02 320

Claims (1)

(57) [Claims] 1. A method for controlling the shape of an H-section steel, wherein cooling water is sprayed on a flange of the H-section steel positioned such that the flange is in a vertical direction to control warpage of the H-section steel.
Measure the flange temperature of the section steel at several locations in the flange width direction, and use this measured temperature to determine the temperature of the upper and lower flanges.
The moment sums M _U and M _L are calculated using the following equations (1) and (2).
From the upper and lower flanges calculated
A shape control method for an H-section steel, wherein a height position of a cooling water injection nozzle is adjusted according to a difference between the temperature moment sums M _U and M _L. Where B: flange width T _U (x), _TL (x): temperature distribution function x: distance from the center of the flange