JPH081201A - Method for manufacturing shaped steel having flange - Google Patents

Abstract

(57) [Abstract] [Purpose] Properly set the depth of the caliper to produce shaped steel without center deviation and variation in flange thickness. [Structure] At least one of a rough universal rolling mill 2 and a finish universal rolling mill 4 is provided with an edger rolling mill 3 having a variable caliper depth for each pass, and a material to be rolled before the edger rolling is performed by a hot dimension measuring device 5. The flange leg length is measured to determine the center deviation of the web, and the upper and lower roll intervals of the web restraining portion of the edger roll in the edger rolling machine 3 are set to the web thickness on the entry side of the pass and the margin amount of the caliper depth obtained in advance. Is set by the roll interval setter 7 so as to be equal to the sum of the above, and the flange width of at least one pass is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a shaped steel having a flange such as an H-shaped steel by hot rolling using a universal rolling mill.

[0002]

2. Description of the Related Art A steel section having a flange such as an H-section steel (hereinafter, representatively described as an H-section steel) is hot manufactured mainly by rolling equipment including a universal rolling mill. 5 (a) and 5 (b) are layout diagrams showing an example of such equipment layout, 1 is a breakdown rolling mill, 2 is a rough universal rolling mill, 3 is an edger rolling mill, 4 is a finishing universal rolling mill. , A plate-shaped slab manufactured by continuous casting, a bloom having a rectangular cross section, a beam blank having a substantially H-shaped cross section with depressions on the upper and lower surfaces, are sequentially hot-rolled by the rolling mill group to form H. Shaped steel is produced.

FIG. 6 is a front view showing an example of a caliber (hole type) in the breakdown rolling mill 1. 11 is an upper roll, 12 is a lower roll, and the numbers in the circles are the number of passes. It moves from the cariba to the cariba on the left one by one, and the rough billet for H section steel is modeled in 7 passes. Figure 7 shows a rough universal rolling mill 2
In the front view showing the roll portion, M is a material to be rolled, 21 is a pair of upper and lower horizontal rolls, 22 is a pair of left and right vertical rolls,
The horizontal roll 21 reduces the web thickness of the material M to be rolled, and the vertical roll 22 reduces the flange thickness.

FIG. 8 is a front view showing a roll portion of the edger rolling machine 3, M is a material to be rolled, and 31 is a pair of upper and lower edger rolls. The edger roll 31 is composed of a central web pressing part 31a for pressing down the web and flange pressing parts 31b provided on both sides of the central web pressing part 31a and having a diameter smaller than this, and both ends of the web pressing part 31a are at both ends of the web of the material M to be rolled. While restraining the portion, the flange pressing portion 31b is pressed in the width direction of the flange.

The rough rolling process using the combination of the rough universal rolling mill 2 and the edger rolling mill 3 is usually repeated a plurality of times. FIG. 9 is a front view showing a roll portion of the finish universal rolling machine 4, M is a material to be rolled, 41 is a pair of upper and lower horizontal rolls, 42 is a pair of left and right vertical rolls, and the horizontal roll 41 is used to The web thickness and the flange thickness are reduced by the vertical roll 42 to finish the final shape.

The above-described rough and finish universal rolling mills 2,
In Fig. 4, rolling is performed by a pair of upper and lower horizontal rolls and a pair of left and right vertical rolls, but the widthwise end of the flange of the material M to be rolled is a free surface and is not subjected to rolling. Therefore, as shown in FIG. 10, there is a possibility that the web position is deviated from the flange (hereinafter, referred to as center deviation). The protrusion amount of the flange from the web indicated by b ₁ and b ₂ is hereinafter referred to as “leg length”. If the center deviation is S, then S = (b ₁ −b ₂ ) / 2, so 1/2 the difference between the upper and lower leg lengths.
According to JIS G3192, the tolerance of center deviation S is as follows: Web height is 300 mm or less: ± 2.5 mm when flange width is 200 mm or less, Web height exceeds 300 mm or flange width
If it exceeds 200 mm, it is specified as ± 3.5 mm.

Various factors can be considered for the occurrence of the center deviation, but they are roughly classified into 1) those caused by the asymmetry of the rolled material and 2) those caused by the asymmetry at the time of universal rolling. 1) is mainly due to the unevenness of filling in the upper and lower and left and right calibers in breakdown rolling, and 2) is the up and down attitude (angle and level) when the material to be rolled is bitten by the universal rolling mill. Is asymmetrical, and the gap between horizontal rolls and vertical rolls is asymmetrical in the vertical and horizontal directions. Furthermore, these factors do not occur individually but in duplicate and affect each other. In many cases, it is presumed that the central bias cannot be eliminated by simply eliminating the above-mentioned asymmetries.

By the way, as described above, an ordinary universal rolling mill is provided with an edger rolling mill.
When the caliper depth of the edger roll indicated by the dimension d (corresponding to the leg length when viewed from the rolled material) is set to an appropriate value, the web is restrained when a difference between the upper and lower leg lengths occurs. With the edger rolling, the web position can be displaced in the flange width direction to correct the relative position between the web and the flange. This is called "replacement" of the web.

However, the caribbean depth d is a constant value as long as the same roll shown in FIG. 8 is used, and cannot be changed to an appropriate value in each pass in accordance with the flange leg length which changes as the pass progresses. . Further, in a rolling mill that rolls H-section steels in which the outer dimensions (soldering) of the upper and lower flanges are constant and the flange thickness and the web thickness are different, the flange leg length also changes when the flange thickness and the web thickness change.

In such a case, the edger roll having the same series, that is, the outer dimensions of the upper and lower flanges being constant and having the caliper depth according to each size having different flange thickness and web thickness, is held and exchanged every time the size is changed. However, not only will the number of rolls be enormous, but the roll replacement time, labor, and other losses will be large, and this cannot be adopted as a practical problem.

Therefore, an edger roll has been developed which can change the depth of the caliber while the roll is attached. For example, FIG. 11 shows a roll of an edger rolling machine for H-section steel described in Japanese Examined Patent Publication No. 3-38926, in which the edger roll is a web reduction roll 31a and a flange reduction roll 31b.
Since the eccentric ring 32 is attached between the shaft part of the web reduction roll 31a and the flange reduction roll 31b, the caliber depth can be changed at any time by rotating this eccentric ring 32. it can.

Further, FIGS. 12 and 13 show an edger roll described in JP-A-63-154204. This edger roll is a flange reduction roll for the web reduction roll 31a.
31b is a small-diameter roll of another axis, is rotated via the intermediate roll 31c, and the position of the flange pressing roll 31b is changed by changing the interval of the intermediate roll 31c as shown in FIGS. 13 (a) and 13 (b). That is, the depth of the caribbean can be changed.

As described above, it is mechanically possible to change the caribbean depth during rolling, but conventionally, it is sufficient to determine how to set and set the cariba depth for each pass. However, the actual situation is that empirical settings have been made through trial and error. Even if the caliper depth is changed during rolling, the following problems occur if the setting is inappropriate. 1) When the caliper depth is too deeper than the leg length after rolling, the web is rolled down in the thickness direction at the web rolling roll. However, since the roll having the variable depth of the caliper as described above has a lower mechanical strength than that of the conventional edger roll, there is a risk of breakage when an excessive load is applied by the web thickness reduction. 2) When the web thickness reduction is performed, the reduction is applied more than planned in the pass schedule, and not only the web thickness variation but also the dimensional disturbance such as the flange width variation due to the edger roll gap variation occurs. 3) If the rib depth is too shallow, there is no constraint on the web even if the upper and lower leg lengths of the flange are uneven, and the effect of correcting the center deviation cannot be obtained.

[0014]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a shaped steel which solves the above-mentioned problems, sets an appropriate caliper depth, and can effectively correct the center deviation. Aim to achieve.

[0015]

SUMMARY OF THE INVENTION According to the present invention, a rough universal rolling machine or a rough universal rolling machine is used for producing a shaped steel having a flange by subjecting a rough shaped steel slab having a web and a flange to rough universal rolling and then finish universal rolling. At least one of the finishing universal rolling mills is equipped with an edger rolling mill in which the caliper depth is variable for each pass, and the flange leg length of the material to be rolled before edger rolling is measured to obtain the center deviation of the web, and the edger rolling mill is used. The upper and lower roll gaps of the edge restraint roll's web restraint part are set to be equal to the sum of the web thickness on the pass entry side and the calculated caliper depth margin, and the flange width of at least one pass or more is set. A method for manufacturing a shaped steel having a flange characterized by performing reduction.

[0016]

[Operation] In an H-shaped steel manufacturing facility, it is possible to measure the flange leg lengths at four locations of the material to be rolled at the same time by using a hot distance measuring device such as a laser range finder as disclosed in Japanese Patent Laid-Open No. 5-107047. This is possible by using a size measuring device.
Such a flange leg length is measured at one or more locations in the longitudinal direction of the material to be rolled, and if there are a large number of measurement points, by averaging the data of the central portion excluding the end portions for each of the upper, lower, left and right flanges, It can be a representative value of each flange leg length.

The present inventor details in a rolling facility in which a universal rolling mill and an edger rolling mill are combined, how "replacement" due to web restraint in the edger rolling affects center deviation in the subsequent universal rolling. investigated. For example, if an H-shaped steel with a center deviation before edger rolling is constrained by the edger and the web is forcibly replaced, the upper and lower leg lengths can be made the same, but in this case the edger rolling is asymmetrical. , The upper and lower flange thickness changes and becomes asymmetric. Figure 2 shows the amount of web replacement (ΔW, mm) on the horizontal axis.
When the relative ratio of the upper and lower flange thickness after replacement (upper and lower maximum flange thickness difference / smaller flange thickness) -1 (1) is plotted as the vertical axis, the web replacement amount ΔW and the value of (1) are It has a negative coefficient and a proportional relationship. Such a vertically asymmetric flange thickness distribution is due to an asymmetric edger rolling.

The increase in flange thickness due to this local reduction is regarded as an increase in the average flange thickness, and the reduction ratio difference between the upper and lower flanges in the subsequent universal rolling is determined, and the relationship with the new center deviation change amount due to the reduction ratio difference is calculated. investigated. FIG. 3 shows the results, where the horizontal axis is (upper flange reduction rate−lower flange reduction rate) (%), and the vertical axis is center deviation change amount (mm), and the same proportional relationship as in FIG. 2 is seen.

From these results, the relationship between the ratio of the replacement amount in the edger rolling and the central deviation before the edger rolling and the central deviation as a result of universal rolling after the edger rolling is plotted as shown in FIG. . The difference between the half of the flange width after edger rolling minus the web thickness and the caribber depth is called the carver depth margin of the edger.

Even if a web of material having a certain center deviation is forced to be replaced by an edger roll to make the upper and lower flange leg lengths uniform, the effect of asymmetric rolling at this time is as shown in FIG. It appears as a bone difference, which results in a difference in rolling reduction between the left and right flanges in the next universal rolling, which causes a center deviation as seen in FIG.

Asymmetric rolling in universal rolling is
It also occurs due to axial deviation of the horizontal roll (thrust deviation) and vertical roll down position deviation of the horizontal roll (horizontal roll level). It is necessary to eliminate the setting error of these facilities as much as possible in order to control.

That is, if the center deviation is generated before the edger rolling and the caliper depth of the edger rolling roll is controlled to make the upper and lower leg lengths uniform, a difference in thickness between the upper and lower flanges remains, which is a universal difference. When the rolling is performed, the center deviation having the opposite sign to that before the edger rolling is generated.
In consideration of the above, the control of the flange upper and lower leg lengths by changing the web in edger rolling takes the above into consideration and obtains the center deviation from the difference between the upper and lower flange leg lengths before the edger rolling. Should be set.

The relationship between the caliper depth margin for replacing the center deviation before the edger rolling as shown in FIG. 4 by the edger rolling and the center deviation in the next universal rolling can be obtained from FIGS. 2 and 3. However, since the slope of the straight line, that is, the degree of influence of each item, varies depending on the cross-sectional size of the product to be rolled, it is necessary to collect data in advance and statistically understand these relationships.

When the combination of the edger rolling and the universal rolling is set as one unit and the rolling for reducing the center deviation by one unit rolling is repeated, the center deviation gradually decreases.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG.
This figure is a plan view showing an example of arrangement of H-section steel manufacturing equipment. Elements common to FIG. 5 are assigned the same reference numerals, 5 is a hot dimension measuring instrument, 6 is a calculator, and 7 is a roll gap. It is a setting device. The H-shaped steel billet shaped by the breakdown rolling mill 1 is supplied to a rolling mill group including a combination of the rough universal rolling mill 2 and the edger rolling mill 3, and is repeatedly rolled multiple times. In the present embodiment, after the material to be rolled is stretched to a length in which the flange thickness at the central portion in the longitudinal direction can be measured by the reciprocating pass of the rough universal rolling mill, the hot dimension measuring device 5
The flange leg lengths at the locations were measured and input to the calculator 6. The calculator 6 calculates the left-right center deviation of the flange from this measurement result, and calculates the web replacement amount in the edger rolling according to the following procedure from the relationship of FIGS. 2 and 3 obtained for each product size. 1) Relational expression between the amount of web replacement shown in FIG. 2 and the relative ratio of the upper and lower flange thicknesses after replacement 2) An expression for obtaining the difference in vertical rolling reduction in universal rolling from the difference in vertical flange thickness caused by 1) 3) FIG. Relational expression between the reduction ratio of the upper and lower flanges and the amount of change in center deviation in universal rolling 4) Difference between the center deviation before edger rolling and the amount of replacement in edger rolling, and the amount of change in center deviation in the next universal rolling From the formula that sets the sum of the values to 0 or an allowable value within a certain target range, the difference between the center deviation before edger rolling and the web replacement amount in edger rolling, that is, the caliper depth allowance, is calculated from the web thickness on the entry side to the edger roll. And the roll gap setting device 7 sets the roll gap.

The web replacement amount in the edger rolling may be calculated online as described above according to the measured value of the center deviation before the edger rolling, but the occurrence of the center deviation for each pass may be grasped in advance. However, it is desirable to obtain the caliber margin amount corresponding to the maximum center deviation that can occur in the pass. That is, compared to the set value of the caliper margin amount corresponding to the maximum center deviation that can occur, if the amount of center deviation before edger rolling is small, the amount of replacement in edger rolling that is necessary is also small. Is.

Further, changing the setting of the caliber depth of the edger roll is most effective in improving the accuracy of the center deviation if it is performed in all passes, but since it takes some time to change the caliber depth online, If necessary, the setting may be changed once in a plurality of passes. Since the target web thickness of each pass and the target value of the flange width after edger rolling are instructed from a higher-level computer (not shown), roll gaps including the caliper depth of the edger rolling machine are set from these values, It is input to the roll gap setting device 7 to perform edger rolling and universal rolling.

H with a web height of 600 mm and a flange width of 300 mm
Shaped steel 3 sizes were produced according to the present invention. Table 1 shows the accuracy of center deviation (1σ). Further, for comparison, the measurement results by the conventional method using an edger with a constant depth of caribbean are also shown, but it can be seen that the present invention significantly improves the accuracy of the center deviation.

[0029]

[Table 1]

Further, along with this, variation in flange thickness is also reduced. In this embodiment, the present invention has been described as being carried out in a rough rolling mill, but if an edger rolling mill is attached to the finishing rolling mill, these may be used as one unit and similar control may be performed. It can also be carried out by both rolling mills and finish rolling mills.

The hot dimension measuring instrument 5 is installed on the upstream side of the universal rolling mill 2 in FIG. 1, but the installation location is not particularly limited as long as the flange leg length after universal rolling can be accurately measured. Further, even in the case of a rolling mill train in which the hot dimension measuring instrument 5 is not installed,
The present invention can be applied if the actual state of the center deviation of each path is grasped in advance, and the depth of the center is set to a depth corresponding to the case where the maximum center deviation occurs. In this case, if the center deviation does not occur, the web does not contact the roll of the web restraint, and in the present invention, since the upper and lower roll gaps are set to be larger than at least the web thickness before the edger rolling, It does not cause problems such as web thickness reduction.

[0032]

EFFECTS OF THE INVENTION According to the present invention, by setting an appropriate caliper depth in an edger roll, it is possible to significantly reduce the center deviation and to manufacture a shaped steel of good quality.

[Brief description of drawings]

FIG. 1 is a layout showing an example of equipment layout according to the present invention.

FIG. 2 is a graph illustrating the operation of the present invention.

FIG. 3 is a graph which similarly illustrates the operation of the present invention.

FIG. 4 is a graph which similarly illustrates the operation of the present invention.

FIG. 5 is a layout diagram showing a conventional equipment layout example.

FIG. 6 is a front view showing an example of a caliber of a conventional breakdown rolling mill.

FIG. 7 is a front view showing a roll portion of a conventional rough universal rolling mill.

FIG. 8 is a front view showing a roll portion of a conventional edger rolling mill.

FIG. 9 is a front view showing a roll portion of a conventional finish universal rolling mill.

FIG. 10 is a conceptual diagram showing central deviation.

FIG. 11 is a partial cross-sectional front view showing a conventional caliber depth variable edger roll.

FIG. 12 is a side view showing another conventional caliber depth variable edger roll.

FIG. 13 is a partial side view showing a part of FIG. 12.

[Explanation of symbols]

 1 Breakdown rolling mill 2 Coarse universal rolling mill 3 Edger rolling mill 4 Finishing universal rolling mill 5 Hot dimension measuring device 6 Computing device 7 Roll gap setting device

Claims (2)

[Claims] 1. When producing a shaped steel having a flange by subjecting a crude shaped steel slab having a web and a flange to a rough universal rolling and then a finish universal rolling, at least one of a rough universal rolling mill and a finish universal rolling mill is used. An edger rolling machine with a variable caliper depth for each pass was installed side by side, and the flange leg length of the material to be rolled before edger rolling was measured to obtain the center deviation of the web, and the upper and lower sides of the web restraining part of the edger roll in the edger rolling machine were determined. It is characterized in that the roll gap is set to be equal to the sum of the thickness of the web on the entrance side of the pass and the preliminarily obtained allowance of the caliper depth, and the flange width of at least one pass is reduced. A method for manufacturing a shaped steel having a flange. 2. The method of manufacturing a shaped steel having a flange according to claim 1, wherein the flange leg length of the material to be rolled before edger rolling is measured by a hot dimension measuring instrument.