JP3283139B2 - Flange shape control method for 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 for controlling a flange shape in a steel material having a flange, that is, an H-shaped steel, an I-shaped steel, a T-shaped steel or various shaped steels such as a channel steel and an angle iron. About.

[0002]

2. Description of the Related Art A shaped steel is obtained by subjecting a material obtained by ingot casting or continuous casting to hot rolling, finishing it into a predetermined sectional shape such as I or H, and then cutting it to a product length. . For example, an H-section steel is roughly rolled using a double horizontal roll having a groove as a rough mill, and then preformed to have a H-section in a rough and intermediate universal mill and an edger mill. Then, a universal steel mill is also used for the final finishing rolling mill to finish the steel into a section steel having an H sectional shape. The H-section steel thus obtained needs to have a flange provided at right angles to the web and a flat flange surface.

[0003] In a universal mill, an angle of a few degrees or less is given to the side surfaces of upper and lower horizontal rolls for rolling a flange portion of a product and vertical rolls on a driving side and an operator side, so that rolling is performed. Stability, prevention of flaws, and improvement of the basic unit of roll are aimed at.

As shown in FIGS. 5 and 6, an H-section steel obtained by rolling by a universal mill having such a roll arrangement has a structure in which the flange is not perpendicular to the web and the flange surface is not flat. There is. In such a case, it is possible to cope by changing the roll of the universal mill and appropriately changing the inclination angle of the roll. However, since there are many product sizes for shaped steel and it is not practically possible to have rolls with different inclination angles for each of these sizes, the angle of the flange with respect to the web is shifted from Is not flattened, that is, a so-called flange warpage occurs, which causes the flange shape to vary.

It is desirable to completely prevent the occurrence of flange warpage. In particular, it is indispensable for industrial production of shaped steel to suppress the amount of flange warpage within a certain range. The amount (d in FIGS. 5 and 6; positive for outward warpage and negative for inner warpage) does not vary greatly, but within a certain range, for example, ± 1.0 for H-section steel.
It is important that it be controlled to within mm.

[0006]

As described above, in the method of coping with flange warpage by changing the roll inclination angle in a universal mill, in order to cope with many sizes of shaped steel, multiple rolls having different roll inclination angles are used. There is a problem in that it has several types of rolls and it is essential to change rolls for each shape steel size. Further, even by adjusting the roll tilt angle, flange warpage may not be suppressed, and a new measure is required. Therefore, an object of the present invention is to open a new way in which the amount of flange warpage can be controlled without largely depending on the roll inclination angle.

[0007]

Means for Solving the Problems The inventors of the present invention have investigated the cause of the occurrence of flange warpage. If the temperature of the rolled material varies between roll chances or between materials, the flange warpage of the product also greatly varies. That is, it has been newly found that the flange warpage has a correlation with the finish temperature of the flange at the time of final rolling. Then, it was confirmed that the relationship between the finished temperature of the flange and the amount of flange warpage of the product was constant with the size of the same type of shaped steel, and the reproducibility was confirmed, and the present invention was completed.

That is, according to the present invention, when hot rolling a shaped steel material to form a predetermined cross-sectional shape, the flange temperature of the shaped steel in the final finish rolling is determined by the type and size of the shaped steel. A flange shape control method for a section steel, characterized in that the amount of flange warpage is controlled by adjusting the temperature to a range of ± 25 ° C. Adjusting the flange temperature by changing the cooling processing conditions or the required rolling time is advantageous for implementation.

Here, the set temperature is a temperature at which flange warpage does not occur, differs depending on the type and size of the shaped steel, and can be determined by experiments.

Next, FIG. 1 shows a rolling equipment used directly in the method of the present invention. In the following description, the case of the H-section steel will be described as an example, as in the above description. However, the present invention is not limited to the type of the section steel, and is advantageously applicable to other sections. The material for the H-section steel is first rough-rolled by a rough mill roll 1 having a groove, and then preliminarily formed by a rough universal mill 2 and an edger mill 3 so that the cross-section becomes substantially H-shaped as shown in FIG. Reduced area rolling is performed to produce an intermediate material.

Here, in order to apply the method of the present invention, in the equipment shown in the drawing, a cooling device 4 is arranged after the edger mill 3, and the cooling device 4 can cool a portion corresponding to a product flange. .

Next, the intermediate material cooled by the cooling device 4 is subjected to finish rolling by a finish universal mill 5 as shown in FIG. 3, and immediately after that, a flange finish temperature is measured by a thermometer 6. Then, the measured temperature is compared with the set temperature determined by the size of the H-shaped steel in the arithmetic unit 7, and the difference between the set temperature and the actual temperature is kept within a range of ± 25 ° C. A command is sent from the control device 8 to the cooling device 4 based on the information from the arithmetic unit 7 to increase the amount of cooling water and the cooling time so that necessary cooling is performed on the intermediate material and the flange temperature in the finish rolling is adjusted appropriately. Adjust to a range.

On the other hand, if the actual temperature is lower than the above range, a command is sent to the cooling device 4 to reduce the amount of cooling water and the cooling time. In addition, a flange heating device (for example,
4-154917, the device shown in Fig. 2)
The device may be operated to heat the flange.

The measurement place of the flange finish temperature is not limited to the position shown in the figure, but may be a place where the finish temperature can be estimated, for example, between the cooling device 4 and the finishing universal mill 5. The temperature measurement position in the flange may be any position representative of the temperature in the flange, for example, 1/1 from the end of the flange width on the outer surface of the flange.
For example, a position of four widths may be used.

Further, since the flange temperature control based on the measurement result of the thermometer 6 cannot be performed in time for changing the water cooling condition for the section steel that has already been subjected to the final finish rolling, for example, a separate If a thermometer (not shown) is installed and the amount of temperature bias with the thermometer 6 is grasped in advance, the cooling condition of the intermediate material is changed by feedforward control based on the temperature measured by another thermometer. If so, it is possible to make the amount of warpage of the portion corresponding to the flange in the intermediate material close to a predetermined value.

In this case, the cooling device is, for example,
A structure having a structure in which a water spray is sprayed on the outer surface of the flange as shown in FIG. 148 can be generally used.

Further, when a cooling device is not provided, it is also possible to adjust the finishing temperature by changing the rolling time and control the amount of flange warpage, such as in standby rolling utilizing natural cooling during rolling.

[0018]

As shown in FIG. 4, it is ideal that the section steel formed into a product after hot rolling has a flange 9 perpendicular to the web 10 and a flat flange surface. . However, conventionally, there has been a problem that the outward warpage shown in FIG. 5 or the inner warpage shown in FIG.

The inventors conducted various experiments on the relationship between the flange finishing temperature and the amount of flange warpage. A typical example of the experiment is 700 × 250 × 12 × 25 m
m (Web height x flange width x web thickness x flange thickness,
FIG. 7 shows the same H-section steel). As shown in the figure, the two show a good correlation. For example, to suppress the amount of flange warpage to ± 1 mm, adjust the flange finishing temperature to a range of ± 25 ° C with respect to the set temperature at which the amount of warpage is zero. It turns out that it is good. Therefore, if the relationship between the flange finish temperature and the flange warpage amount as shown in FIG. 7 is grasped in advance, the allowable flange warpage amount (for example, ± 1 m) can be obtained.
m), the cooling device 4 is controlled by the control device 8 via the computing unit 7 so that the actual temperature of the thermometer 6 shown in FIG. For example, the cooling conditions such as the amount of water may be changed.

In addition, the above-mentioned experiment was carried out similarly for various shaped steels and various sizes. As a result, if the flange finishing temperature was adjusted within a range of ± 25 ° C. with respect to the set temperature, any one of the experimental objects could be obtained. Also in the above, since the flange warpage of the product is within an allowable range, in the present invention, the flange finishing temperature is adjusted within a range of ± 25 ° C. with respect to the set temperature.

[0021]

Example: From a material for H-section steel (SM490A), which has the usual composition of H-section steel obtained by continuous casting, size 700 × 25
In manufacturing an H-section steel of 0 × 12 × 25 mm, the finish temperature of the flange was adjusted to a set temperature (660 ° C.) ± 25 ° C. obtained in advance by experiment, as shown in FIG. Further, in manufacturing an H-section steel having a size of 700 × 250 × 12 × 19 mm with the same roll without exchanging the roll, the flange finishing temperature was adjusted to a range of 730 ° C. ± 25 ° C. As a result of continuing this operation, all of the obtained steel bars were acceptable products in which the warpage of the flange was within ± 1.0 mm.

Further, for comparison, when the operation was performed without adjusting the flange finish temperature, 40% of the obtained section steels were warped which required straightening treatment.

[0023]

According to the present invention, the amount of warpage of a flange of a product can be suppressed to a predetermined range without replacing equipment such as a roll. In particular, if feed-forward control is performed by a water cooling device, the amount of flange warpage in the intermediate material in the longitudinal direction can be made constant, and the amount of flange warpage of the product can be extremely easily suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a rolling facility used in the method of the present invention.

FIG. 2 is a schematic diagram showing a forming process in the production of a shaped steel.

FIG. 3 is a schematic view showing a forming process in the production of a shaped steel.

FIG. 4 is a schematic view showing an ideal shape of a section steel.

FIG. 5 is a schematic view showing the shape of a section steel in which warpage has occurred.

FIG. 6 is a schematic diagram showing the shape of a section steel in which warpage has occurred.

FIG. 7 is a diagram showing a relationship between a flange finishing temperature and a flange warpage amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coarse mill 2 Coarse universal mill 3 Edger mill 4 Cooling device 5 Finishing universal mill 6 Thermometer 7 Computing unit 8 Control device 9 Flange 10 Web

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-31331 (JP, A) JP-A-5-305328 (JP, A) JP-A-5-57302 (JP, A) JP-A-62-231 235424 (JP, A) JP 2-17241 (JP, B2) JP 59-288 (JP, B2) (58) Fields studied (Int. Cl. ⁷ , DB name) B21B 37/16 B21B 37 / 74

Claims (3)

(57) [Claims] When a section steel is subjected to hot rolling to be processed into a predetermined cross-sectional shape, a flange temperature of the section steel in the final finish rolling is set to a set temperature determined by a type and a size of the section steel. A method for controlling a flange shape of a section steel, wherein an amount of warpage of the flange is controlled by adjusting the temperature within a range of ± 25 ° C. 2. A method of adjusting a flange temperature by a cooling process.
The method for controlling a flange shape of a shaped steel according to claim 1. 3. The method according to claim 1, wherein the flange temperature is adjusted by changing the required rolling time.