JP2973859B2 - H-section flange width control method - 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 manufacturing an H-section steel, and more particularly to a method of controlling a flange width of an H-section steel in a group of coarse universal rolling mills for rolling an H-section provided with at least one edger rolling mill.

[0002]

2. Description of the Related Art H-section steels, such as blooms, slabs, and beam blanks, are first heated in a heating furnace, and then roughly rolled by a breakdown rolling machine incorporating rolls having a caliber shape. The material is rolled by performing a plurality of pass rollings in a rough rolling mill group including a rough universal rolling mill U shown in FIG. 11A and an edger rolling mill E shown in FIG. 11B. The coarse universal rolling mill U is a method in which the material to be rolled is rolled by the horizontal roll 4 and the vertical roll 5 to reduce the flange thickness and the web thickness of the material to be rolled so as to approach a specified product thickness. E is for rolling down the front end of the flange of the material to be rolled by the horizontal roll 6 to finish it to a specified flange width.

[0003] In the above-mentioned method for producing an H-section steel, as a method for improving the dimensional accuracy of the flange width by changing the roll opening degree of an edger rolling mill during rolling, for example, Japanese Unexamined Patent Publication No.
There is one disclosed in JP-A-11611. As shown in FIGS. 12A and 12B, the flange width of the material to be rolled is measured directly or indirectly, and the main arithmetic unit 30 uses a flange width expansion formula for calculating the flange width expansion. Then, the roll opening of the edger rolling mill is continuously adjusted so that the flange width after the universal rolling in the next pass becomes the target width. Further, Japanese Patent Application Laid-Open No. 1-24
No. 9210 discloses a control method for setting the roll opening of an edger rolling mill in consideration of material constants.

[0004]

A conventional flange width control method is to set a roll opening of an edger rolling mill from a result of calculating a flange width after universal rolling for a stationary portion, and It did not have a function to control the flange width in the unsteady part at the rear end of the material tip. For this reason, the flange width of the front and rear end unsteady portions could not be rolled as intended, and the flange width deviated from the target dimension as shown in FIG. This is because the unsteady deformation of the front and rear ends of the material to be rolled was not considered.
For example, as shown in FIG. 14, even if the flange width B1 of the rolled material is constant up to the end, if the edging amount is fixed, the flange width B2 after the subsequent universal rolling is continued.
In many cases, the dimension becomes narrower toward the end. This difference is due to the fact that the metal at the end due to the reduction by edging rolling is more likely to flow in the longitudinal direction than the steady part, and the dog bone at the end is smaller than the steady part, and the width in the universal rolling is reduced. This is caused by the spread being reduced at the end. The width expansion behavior of the unsteady portion changes depending on the conditions of rough rolling and universal rolling.
Such a defective flange width dimension at the end reduces the yield due to troublesome maintenance in a later process, cutting and discarding of the defective dimension portion, and lowers productivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an H-section steel having good dimensional accuracy and yield, in which a flange is rolled to a target width even at the front and rear ends. It is an object of the present invention to provide a flange width control method.

[0006]

In order to achieve the above object, the present inventors have made various studies and found that at least one rough universal rolling mill and at least one edger rolling mill are arranged adjacent to each other. In the group of coarse universal rolling mills,
When rolling the unsteady portion at the leading and trailing end of the material to be rolled, in the case of the leading end of the rolled material, the roll opening degree of the edger rolling machine with respect to the unsteady portion at the leading end is set according to the form of the leading end of the rolled material. Set larger or smaller than the set value of the part,
Then, by continuously decreasing or increasing to converge to the set value of the steady portion, and in the case of the rear end portion of the rolled material, by continuously increasing or decreasing from the set value of the steady portion, the next universal The present inventors have found that the flanges at the front and rear ends can be made equal in width to the stationary portion in rolling, and have reached the present invention. That is, at the leading and trailing end of the material to be rolled, the dog bone forming behavior by the edger rolling and the width spreading behavior by the universal rolling are measured or predicted to be different from the steady part, thereby continuously adjusting the roll opening degree of the edger rolling mill at the end. We have developed a method to adjust to this. In the present invention, means for continuously increasing or decreasing the roll opening of the edger rolling mill at the leading and trailing ends of the material to be rolled does not require any limitation. Examples of such means include a roll opening adjustment method using hydraulic pressure, a method using a screw down and an electric motor, or a combination of these.

[0007]

The operation of the present invention will be described below in detail along with the effects. FIG. 1 shows an example of an arrangement of rolling equipment for H-section steel to which the present invention is applied. Rolled material is heated and broken down by rolling mill B
The rough rolling is performed by D, and then the rolling is performed in a plurality of passes by the rough rolling mill groups R1 and R2. Here, FIG. 1 shows an example in which a universal rolling mill U1 and an edger rolling mill E1 are arranged adjacent to each other as a rough rolling mill group, but the number and arrangement of the rolling mills are limited to this example. Not one, each one
Any format may be used as long as it is arranged adjacent to at least the group, and the order can be freely determined. Further, the rough rolling mill group exemplifies the arrangement of two rolling facilities, but these may be one or three or more. The material to be rolled that has passed through the rough rolling mill groups R1 and R2 is finally finished by the finishing universal rolling mill F to have the target dimensions.

[0008] These arrangements are the same as those of the prior art, but in the present invention, the roll opening of the edger rolling mill of the rough rolling mill group is determined by rolling the unsteady part at the leading and trailing end of the rolled material. Rolling is performed while continuously increasing or decreasing the set value. When the edge of the flange is lowered by an edger rolling mill, a dog bone 7 as shown in FIG. 2 is formed. The shape of this dog bone naturally varies depending on the amount of reduction at the tip of the flange, but the metal flow in the rolling direction tends to increase at the rear end of the material to be rolled. The bone is smaller than the steady part. If this is rolled by a subsequent universal rolling mill, the flange width at the end of the material to be rolled tends to be smaller than that in the steady portion where the dog bone is formed large. Therefore, in the present invention, a method has been developed for adjusting the roll opening of an edger rolling mill so that the flange width after universal rolling becomes equal to the steady portion in the unsteady portion at the leading and trailing end of the material to be rolled.

FIG. 3 is a schematic view showing an edger rolling method according to the present invention. The horizontal line in the figure indicates the position of the upper end of the flange when the flange is viewed from the side. The rolled material flange width B1 before edging is constant up to the tip. When this is rolled down by an edger rolling mill, the roll opening at the leading end is made larger than the set value of the steady portion, and the roll opening is continuously adjusted during LT until the steady portion is reached after the rolled material is caught. The flange width is wide at the tip end as shown by BE in the figure, and the width gradually narrows as it approaches the steady part,
Except for the stationary part, it is formed in a shape having a constant width. Although not shown in the drawing, the roll opening of the edger rolling mill is also adjusted at the rear end so that the flange width becomes wider toward the end. When this is rolled by an adjacent coarse universal rolling mill, the front and rear end portions where the dog bone is difficult to be formed and the width expansion is small are widened in advance, and as a result, the dog bone is large and the flange width expansion is the same as the steady portion. Width and flange width B after universal rolling
As a result, a material to be rolled in which 2 is constant up to the end is obtained.

FIG. 4 shows a flange width control method according to the present invention when the flange width is narrow at the front and rear ends of the material to be rolled before edging. By increasing the roll opening of the edger rolling mill at the end than in the case of FIG. 2, and narrowing the roll opening as approaching the steady portion, the end width drop of the material to be rolled is corrected and continued. The flange width after universal rolling can be made constant. Depending on the rolling conditions of rough rolling and universal rolling, the end of the material to be rolled may be wider than the steady portion, but in this case, the roll opening of the edger rolling machine is constantly set at the end of the material to be rolled as shown in FIG. The roll opening may be narrower than the fixed portion, and the roll opening may be increased as the position approaches the steady portion. In addition, the adjustment of the roll opening degree of the edger rolling mill in the unsteady region of the rolled material end is not limited to only the increase or only the decrease, and the flange width of the rolled material end is determined by a combination of both. Even if it is, it can respond. Further, the present invention will be described in detail with reference to examples, but these are exemplifications of the present invention and do not limit the contents of the present invention described so far.

[0011]

FIG. 6 is a control block diagram when the flange width control method of the present invention is implemented by actually measuring the flange width before the edger rolling. The flange width 9 is measured over the entire length by the flange width meter 8, and the measurement result is used as the main processing unit 1.
Enter 0. At this time, the flange width measurement positions in the material are simultaneously detected by the signals of the pulse transmitters 12 and 13 installed in the drive motor 14 of the universal rolling mill and the drive motor 15 of the edger rolling mill, so that the front and rear ends and the flange of the steady portion are simultaneously detected. Find the unsteady part length together with the width difference. Using this result, the roll opening of the edger mill was adjusted during the reverse rolling in the next pass. Here, in order to easily and reliably control the roll opening during edger rolling, the roll opening adjustment is linearly changed as shown in FIG. 7, and the tightening amount ΔB _ET is set as follows. lead. After the edger rolling, the width expansion when the stationary part is rolled by the universal rolling mill is expressed by the following equation.

[0012]

(Equation 1) B ₁ : Flange width before edger rolling B _E : Flange width after edger rolling B ₂ : Flange width after universal rolling t _F1 : Flange thickness before edger rolling t _FE : Flange thickness after edger rolling t _F2 : Flange thickness after universal rolling t _W1 : Web thickness before edger rolling t _WE : Web thickness after edger rolling t _W2 : Web thickness after universal rolling A _F : Flange cross-sectional area A _W : Web cross-sectional area I _dE : Projected contact arc length of edger rolling ：: Coefficient

The width of the tip is expressed as follows.

[0014]

(Equation 2) B _ET : Flange tip width after edger rolling B _2T : Flange tip width after universal rolling c: Coefficient R _V : Vertical roll radius of universal rolling mill

The conditions for preventing the tip from dropping after universal rolling are as follows:

[0016]

B ₂ = B _2T (3) From the equations (1) and (2), the edger tightening amount ΔBET is

[0017]

(Equation 4)

The length LT of the opening adjustment from the end was the same as the unsteady portion length measured after universal rolling. From ΔBET and LT, the tightening control speed Vr of the roll opening of the edger mill can be calculated by the following equation. _{V r = (2 · π ·} R E · N RE · ΔB ET) / (60 · L T) ... (5) R E: Ejjaroru radius N _RE: Ejjaroru rpm

FIG. 8 is a diagram showing the longitudinal distribution of the product flange width when the flange width control according to the present invention is performed using the derived tightening amount of the formula (5). The flange width is also the target value in the unsteady portion at the front and rear ends of the material to be rolled. On the other hand, FIG. 9 is a diagram showing the product flange width when the method of the present invention is not used. The flange width of the stationary portion is set to be larger than the target value of 300 mm so that the flange width drop portion at the tip falls within the dimensional tolerance. For this reason, the steady part cross-sectional area becomes unnecessarily large, and the yield is reduced.

Further, the present invention does not necessarily require measurement of the flange width, and measures the flange width difference between the unsteady portion and the steady portion from the flange width of the material to be rolled after rolling, and
From this result, it is also possible to determine the roll opening adjustment amount and the adjustment length of the edger rolling mill, and this method can provide a sufficient effect. FIG. 10 is a diagram showing the product flange width distribution when the roll opening adjustment amount of the edger rolling mill is determined by such a method and rolling is performed, and the flange width at the end is substantially equal to the steady portion. You can see that there is. As shown in the above embodiments, the flange width control method of the present invention enables the flange to be rolled to the target width even in the unsteady region at the end of the material to be rolled. It is needless to say that the use of the conventional technique in combination with the flange width control method in the steady portion improves the flange width dimensional accuracy over the entire length of the material to be rolled.

[0021]

As described above, according to the present invention, the roll opening of the edger rolling mill is controlled in consideration of the deformation of the unsteady portion, so that the target flange width reaches the front and rear ends. A material to be rolled is obtained. This eliminates the need for maintenance in the post-process, and also improves the yield because parts whose flange width has been defective can now be used as products.

[Brief description of the drawings]

FIG. 1 is a diagram showing a rolling mill row according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a state of occurrence of a dog bone during edger rolling.

FIG. 3 is a schematic diagram showing a flange width control method according to the present invention when the rolled material flange width is constant over the entire length.

FIG. 4 is a schematic view showing a flange width control method according to the present invention when a flange width at an end of a material to be rolled is narrower than a steady portion.

FIG. 5 is a schematic diagram showing a flange width control method according to the present invention when a flange width at an end of a material to be rolled is wider than a steady portion.

FIG. 6 is a block diagram showing a flange width control device according to one embodiment of the present invention.

FIG. 7 is a schematic diagram showing a method of lowering a flange tip according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating a flange width distribution of a product according to an embodiment of the present invention.

FIG. 9 is a diagram showing a flange width distribution of a product according to a conventional method.

FIG. 10 is a diagram illustrating a flange width distribution according to an embodiment of the present invention.

FIG. 11 is a diagram showing a mechanism of a rough universal rolling mill and an edger rolling mill.

FIG. 12 is a block diagram of a control system to which a conventional flange width control method is applied.

FIG. 13 is a diagram showing an example of a flange width shape at an end of a material to be rolled.

FIG. 14 is a schematic diagram showing a change in flange width at a non-stationary portion at the leading end of a material to be rolled by a conventional method.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor, Motohisa Yoshida 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP-A-59-16611 (JP, A) JP-A Sho 57-193203 (JP, A) JP-A-63-199001 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 37/16 B21B 1/08

Claims (2)

(57) [Claims] 1. A method for controlling a flange width of an H-section steel in a group of rough universal rolling mills for H-section rolling provided with at least one edger rolling mill, comprising: Considering that the bone formation behavior and the flange spreading behavior at the time of universal rolling are different from the steady part, the roll opening of the edger rolling mill with respect to the unsteady part at the leading end of the rolled material,
Depending on the form of the rolled material tip, it is set to be larger or smaller than the set value of the steady part, and is continuously decreased or increased to converge on the set value of the steady part, and in the subsequent universal rolling mill A flange width control method for an H-section steel, wherein a flange at a leading end of a rolled material has a width equal to a width of a stationary portion. 2. A method of controlling a flange width of an H-section steel in a group of rough universal rolling mills for H-section steel rolling provided with one or more edger rolling mills, comprising the steps of: Considering that the dog bone forming behavior and the flange spreading behavior at the time of universal rolling are different from the steady part, the roll opening of the edger rolling mill with respect to the unsteady part at the rear end of the rolled material is
Depending on the configuration of the rear end of the rolled material, it is continuously increased or decreased from the set value of the steady portion, and the flange of the rear end of the rolled material is made the same width as the steady portion in the subsequent universal rolling mill. Method for controlling flange width of H-section steel.