JPH10216803A - Control method of web center deviation of H-section steel - Google Patents

Abstract

(57) [Summary] In manufacturing an H-section steel, it is possible to reliably reduce the deviation of the center of the web of the H-section steel over the entire length of the material to be rolled by a relatively simple configuration. A deviation measuring device (7) for a center of a web at an upstream side, a downstream side, or an intermediate position of a rough universal rolling mill group (5).
Measure the deviation S of the web center of the H-section steel with
The material temperature T of the H-section steel is measured by the temperature measuring device 8, and the measurement result ΔS of the deviation of the center of the web, the biting angle and the center of the web depending on the temperature distribution in the rolling longitudinal direction of the material to be rolled obtained in advance. Of the material to be rolled into the rolling mill group ΔH (= ΔS / f) based on the relationship f (T)
(T)) is continuously changed to control the deviation of the center of the web over the entire length of the material to be rolled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for correcting a deviation of the center of a web in a hot rolling process of an H-section steel or a similar section steel (hereinafter, simply referred to as an H-section steel).

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4 (a), an H-section steel is heated by heating a billet, then a double hole type rolling mill (breakdown mill), a coarse universal rolling mill, an edger rolling mill, and the like. It is shaped into a predetermined cross-sectional dimension by successively rolling with a finishing universal rolling mill, and then manufactured by cutting, cooling, straightening, and inspection. In the coarse universal rolling mill, a horizontal roll
Rolling is performed by a vertical roll to reduce the thickness of the web flange to a predetermined size. Here, the end of the flange that is not rolled is reduced by an edger rolling mill, and the flange width is set to a predetermined size. After repeating the rolling by the rough universal rolling mill and the edger rolling mill a plurality of times, the final cross section is finished by the finishing universal rolling mill.

In such universal rolling, the center of the flange in the width direction of the flange and the thickness of the web are changed due to a deviation between the universal mill pass line and the center of the material to be rolled, uneven thickness of the flange, clearance between the edger roll and the material to be rolled, and the like. The centers of the directions do not match, and a deviation of the center of the web occurs as shown in FIG. 4 (b). Regarding the shape and dimensions of H-shaped steel products, dimensional tolerances are defined by JIS standards and the like, and the deviation S at the center of the web sufficiently satisfies the JIS standards even if manufactured by a conventional method. In recent years, the secondary processing has been diversified depending on the application, and a product having a small amount of deviation at the center of the web and having higher dimensional accuracy has been demanded. In particular, H-section steel is manufactured into a long molded product by rolling, and then cut into product dimensions. However, since the products are used by connecting the products in the longitudinal direction as needed, the product is manufactured by universal rolling. In such a case, it is necessary to make the long molded product with a small deviation of the center of the web over the entire length.

Therefore, conventionally, the following various methods have been proposed to control the deviation of the center of the web.

Conventional example 1 (Japanese Patent Laid-Open No. 59-144502)
Publication) The pass line height of the universal rolling mill is determined in advance, and at least the flange upper end height is measured at the entrance of the universal rolling mill at the time of rolling, and the flange is determined based on the pass line height and the flange upper end height. A method in which a target height of a lower end is calculated and calculated, and a guide roller in front of a rolling mill is moved up and down to adjust the lower end of the flange of the material to be rolled to the target height.

Conventional Example 2 (Japanese Unexamined Patent Publication No. Sho 59-16612) A deviation of the center of the web of the material to be rolled is detected at the entrance or exit of the rolling mill, and based on the detection result, the material restraining device in front of the rolling mill is determined. A method for continuously controlling the deviation of the center of the web by changing the biting angle of the material to be rolled into the rolling mill by adjusting the height of the roll.

Conventional example 3 (JP-A-5-177226) Web position (pass line) in front of and behind a rolling mill
Is detected, and this is compared with the target pass line. When the deviation exceeds the reference value, the horizontal roll rolling position /
A method that corrects the press-up position or the vertical position of the tilting table to correct the deviation of the center of the web. When the material to be rolled is first bitten into the universal mill, the position of the horizontal roll or the like is feed-forward controlled in accordance with the detected value before rolling, and thereafter, feedback control is performed in accordance with the detected value after rolling.

Conventional Example 4 (Japanese Unexamined Patent Publication (Kokai) No. 2-104413) A deviation of a web center of a material to be rolled is detected before and after an edger rolling mill installed between a first coarse universal mill and a second coarse universal mill. And based on this detection,
A method for continuously controlling the deviation of the web center by changing the pass center of the edger mill. If the deviation of the center of the web is shifted upward by ΔS, if the path center of the edger rolling mill is moved upward by ΔH, a downward moment acts on the web at the coarse universal mill entry side, and the web is moved downward. Shifts downward.

[0009]

However, in the prior art 1, when the material to be rolled is already decentered at the center of the web, or when the rolling direction and the shape or material temperature in the cross section are non-uniform. However, with only the position information of the upper end of the flange width, the bias of the web center cannot be improved, and in some cases, the bias of the web center deteriorates.

On the other hand, in Conventional Examples 2 to 4,
Measure the deviation of the web center of the material to be rolled, not the upper end position of the flange width, and based on the measurement result, the pass line position of the horizontal roll of the universal rolling mill, the pass center of the edger rolling mill, or the universal rolling mill Since the deviation of the center of the web is controlled by feedback control or feedforward control of the entrance table position, the deviation of the center of the web can be improved.

However, even with the control methods of Conventional Examples 2 to 4, there has been a problem that the deviation of the center of the web cannot be kept within the target value. That is, in the rolling of the H-section steel, as shown in FIG. 5, unevenness of the center of the web is likely to occur in the rolling longitudinal direction of the material to be rolled. This is caused by non-uniformity of the shape and temperature in the cross section in the rolling direction, and in Conventional Examples 2 to 4, the control for the deviation change of the web center caused by these elements is not mentioned. It was not possible to reduce the web center bias over the entire length of the material.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to ensure that the deviation of the center of the web of the H-section steel over the entire length of the material to be rolled by a relatively simple structure. It is another object of the present invention to provide a control method which can reduce the number of times.

[0013]

In order to achieve the above object, according to the present invention, there is provided a rolling mill group comprising a coarse universal rolling mill and an edger rolling mill, or a first coarse universal rolling mill and a second coarse universal rolling mill. And in a rolling mill group consisting of an edger rolling mill arranged in between these, upstream, downstream, or at an intermediate position of the rolling mill group, to measure the deviation of the web center of the H-section steel, the measurement results and Based on the relationship between the biting angle depending on the temperature distribution in the rolling longitudinal direction of the material to be rolled and the web center bias variation previously determined, the biting height of the material to be rolled into the rolling mill group is continuously determined. To control the deviation of the center of the web over the entire length of the material to be rolled.

FIG. 5 shows the rolling line shown in FIG.
It is the measurement result of the deviation | deviation of the web center of the 7th pass and the 9th pass at the time of performing the coarse universal rolling of several passes by the conventional method. Here, in the eleventh pass, the biting height was controlled by a roller guide on the front of the coarse universal rolling mill based on the measurement result of the deviation of the center of the web in the ninth pass so as to set the deviation of the target web center to zero. The result. The control formula at this time is as follows: ΔS is the amount of change in the deviation of the web center at the ninth pass (the deviation between the target value and the measured value), and ΔH is the amount of change in the height of the roller guide pass line from the universal rolling mill pass line. Then, the following equation (1) was used (Japanese Unexamined Patent Publication No.
No. 5201, or Hei 5 125th Spring Iron and Steel Association Lecture Meeting Development of bias control technology centering on H-section steel web).

[0015]

(Equation 1)

According to this conventional example, it can be seen that the effect of improving the deviation of the center of the web by changing the bite height of the material to be rolled into the universal rolling mill is not the same over the entire length in the rolling direction. As a result of repeated tests and experiments, it has been found out that the cause is caused by non-uniformity of the temperature in the rolling direction and the temperature in the cross section of the material to be rolled.

That is, since the deformation resistance of the material changes depending on the temperature, the material to be rolled having a temperature difference in the longitudinal direction of the rolling can be fixed even if the biting angle into the universal rolling mill is constant.
A difference occurs in the deviation change amount at the center of the web. Therefore, if the temperature of the material to be rolled is known, the bite angle required to correct the deviation of the center of the web can be made an appropriate value, and ΔS
It has been found that the relationship between ΔH and ΔH may be expressed by the following equation (2).

[0018]

(Equation 2)

Here, the influence coefficient f (T) of the equation (2)
Is the deviation control efficiency η at the center of the web, which varies with the temperature T.
(= Web center deviation before and after universal rolling /
The amount of change in the vertical direction of the rolled material with respect to the web path center) is obtained in advance, and this is registered in the arithmetic unit.

From the above, the deviation S of the center of the web with respect to the entire length of the material to be rolled in the previous pass is measured, and the temperature T in the rolling direction of the material to be rolled is measured. From the coefficient f (T) and the deviation change amount ΔS of the center of the web, ΔH that satisfies the expression (2) is calculated, and the path center of the roller guide in the next pass is continuously determined based on the ΔH calculated over the entire length of the material to be rolled. , It is possible to reduce the deviation of the center of the web over the entire length of the material to be rolled.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows an example of a rolling process layout according to the present invention, that is, a control of deviation of a web center. FIG.
FIG. 1 shows an example of a pass line changing unit according to the present invention, and an example of a web center deviation measuring apparatus used in the present invention. FIG.
2 shows the distribution of the temperature in the rolling longitudinal direction of the material to be rolled and the distribution of the deviation of the center of the web in the rolling longitudinal direction.

In FIG. 1 (a), hot rolling of an H-section steel
A coarse universal rolling mill group 5 composed of a double type reversible coarse hole type rolling mill (breakdown mill) 2, a reversible coarse universal rolling mill 3, and a reversible edger rolling mill 4, which are arranged in order from the heating furnace 1 side; The finishing is performed by a universal rolling mill 6. The coarse universal rolling mill group 5 is configured by arranging an edger rolling mill 4 between a first reversible coarse universal rolling mill 3-1 and a second reversible coarse universal rolling mill 3-2. In the group of universal rolling mills 5, the crude steel slab roughly formed by the breakdown mill is formed by a plurality of passes in the forward and reverse directions to almost the cross-sectional dimensions of the final product, and finally finished using the finishing universal rolling mill 6. The coarse universal rolling mill group 5 may be configured by arranging one coarse universal rolling mill 3 and one reversible edger rolling mill 4 each.

In such a rolling step, a web center deviation measuring device 7 is provided downstream of the rough universal rolling mill group 5.
Is installed, and the deviation of the web center of the H-section steel is measured. 2 (b) and 2 (c) are used as the deviation measuring device 7 for the center of the web. The center deviation meter is provided with a scanning laser distance meter 2 on a water-cooled measurement stand 20.
A total of eight 1-point and 1-point laser distance meters 22 are installed, the distance to the upper and lower end faces of the flange is measured by the scanning laser distance meter 21, and the distance to the web is measured by the 1-point laser distance meter 22. The difference between the upper and lower leg lengths a and b is calculated, and (ab) / 2 is output as a bias value at the center of the web.

The deviation measuring device 7 at the center of the web can measure continuously in the longitudinal direction of the H-section steel, and can measure both directions of the odd-numbered pass and the even-numbered pass. As shown in FIG. 1 (b), an odd-numbered path in the positive direction in the rough universal rolling is measured. A temperature measuring device 8 such as a radiation thermometer is installed at the same position as the deviation measuring device 7 at the center of the web, and the temperature of the material to be rolled is continuously measured over the entire length in the rolling direction in the same odd-numbered pass as the deviation measurement at the center of the web. Measure.

The second rough universal rolling mill 3-2
A roller guide 9 is disposed on the entry side of the roller guide 9. As shown in FIG. 2 (a), the roller guide 9 vertically adjusts the position of the material to be rolled into the universal rolling mill by vertically moving a roller 10 for restraining one of the right and left flanges from above and below. In addition, it is possible to control (correct) the bias of the center of the web. If the deviation of the center of the web is deviated upward, the roller guide 9 is raised.

The deviation amount S of the center of the web and the temperature T of the material to be rolled measured in the odd-numbered passes are input to the arithmetic unit 12.
FIG. 3 (a) shows the distribution of the temperature T in the longitudinal direction of the rolled material.
Here is an example. In the arithmetic unit 12, the influence coefficient f (T) of the above-described equation (2) that differs depending on the temperature T is obtained and registered in advance, and the material to be rolled is calculated from ΔS and f (T) using the equation (2). Adjustment amount Δ of roller guide 9 over the entire length of
H is calculated, the roller guide 9 is continuously moved up and down in the next odd-numbered pass using various ΔH in the rolling longitudinal direction of the material to be rolled, and the biting position into the second coarse universal rolling mill 3-2 is determined. The web center bias is controlled by continuous changes.

The means for changing the pass line position is as follows.
Not limited to the roller guide, a tilting table 11 shown in FIG. 1B or a horizontal roll of a universal rolling mill may be used. Further, although the deviation measuring device and the temperature measuring device at the center of the web are installed on the downstream side of the rough universal rolling mill group, they may be installed on the upstream side, or may be installed on the upstream and downstream sides.

When the deviation control of the center of the web was performed for each odd-numbered pass by employing the above-described deviation control method of the center of the web of the present invention, the result shown in FIG. 3B was obtained. FIG. 3 shows a case where the invention is applied to H500 × 200 × 10/16, and it can be seen that the deviation of the web center is within the target value over the entire length of the material to be rolled. Also,
The following table is an example applied to other sizes. As is clear from this table, while the conventional deviation amount of the center of the web is a large value of 1 mm or more, in the present invention, the average value and the standard deviation of the deviation amount of the center of the web are both the material to be rolled. It is 1 mm or less over the entire length, and a high effect is obtained.

[0029]

[Table 1]

[0030]

As described above, the present invention measures the deviation of the center of the web of the H-section steel at the upstream, downstream, or intermediate position of the group of rough universal rolling mills, Based on the relationship between the bite angle depending on the temperature distribution in the rolling longitudinal direction of the rolled material and the amount of deviation in the center of the web, the height of bite of the rolled material into the rolling mill group is continuously changed. Since the deviation of the center of the web is controlled over the entire length of the material to be rolled, the deviation of the center of the web of the H-section steel can be reliably reduced over the entire length of the material to be rolled. In addition, with a relatively inexpensive configuration in which a temperature measuring device is simply added to the web center bias control, the web center bias of various sizes can be reduced over the entire length of the material to be rolled.

[Brief description of the drawings]

FIG. 1A is a schematic plan view showing an example of a rolling process layout of the present invention, and FIG. 1B is a block diagram and a schematic plan view showing an example of web center deviation control of the present invention.

2A is a side view showing a roller guide according to the present invention, and FIGS. 2B and 2C are a front view and a partially enlarged view showing an example of a web center deviation measuring device used in the present invention.

FIG. 3 (a) shows the distribution 1 of the temperature in the rolling longitudinal direction of the material to be rolled.
FIG. 4B is a graph showing an example, and FIG. 5B is a graph comparing the distribution of the deviation of the center of the web in the rolling longitudinal direction of the material to be rolled by the present invention and the conventional method.

FIG. 4 (a) is a schematic plan view and detailed view showing a layout of a general H-section rolling process and each rolling mill, and FIG. 4 (b) is a front view showing a deviation of the web center of the H-section steel.

FIG. 5 is a graph showing a distribution of a deviation of a web center in a rolling longitudinal direction of a material to be rolled by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heating furnace 2 ... Double type rough hole type rolling mill 3 ... Coarse universal rolling mill 4 ... Edger rolling mill 5 ... Coarse universal rolling mill group 6 ... Finishing universal rolling mill 7 ... Web center deviation measuring device 8 ... Temperature measurement Device 9 ... Roller guide 10 ... Roller 11 ... Tilting table 12 ... Computing device

Claims (1)

[Claims] 1. A rolling mill group comprising a coarse universal rolling mill and an edger rolling mill, or a rolling mill comprising a first coarse universal rolling mill, a second coarse universal rolling mill and an edger rolling mill disposed therebetween. In the group, upstream, downstream, or at an intermediate position of the rolling mill group,
Measure the deviation of the center of the web of H-section steel,
Continuously determine the bite height of the rolled material into the rolling mill group based on the relationship between the bite angle and the deviation change amount of the web center depending on the temperature distribution in the rolling longitudinal direction of the rolled material determined in advance. And controlling the deviation of the center of the web over the entire length of the material to be rolled.