JP3272856B2 - Rolling method of shaped steel with flange - 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 rolling a section steel having a flange, and more particularly to a method for efficiently forming the web height of an H-section steel without a defective shape.

[0002]

2. Description of the Related Art At present, an H-section steel manufactured by rolling,
Shaped steels having flanges, such as I-shaped steels, are characterized by an extremely large number of types and sizes. With the diversification of customer needs, the trend toward more types and sizes is increasing. In order to manufacture these various types and sizes of shaped steel by the conventional rolling method, a large number of dedicated rolling rolls and dedicated guides corresponding to the shaped steel are required, and the number of times of changing the roll guide is increased. Therefore, time loss increases, and productivity is significantly impaired.

[0003] As a specific example, the case of H-section steel will be described below. FIG. 8 (a) shows a typical example of a conventional row of H-section steel rolling equipment, which is a breakdown rolling mill BD in a rough rolling step I, followed by a four-roll universal rolling in an intermediate rolling step II. And a four-roll universal rolling mill FU for finishing in the finishing rolling step III.

FIG. 8 (b) shows the shapes 4, 5, 5 of the rolled material formed in the rolling steps I, II, III in FIG. 8 (a).
6 is shown. FIG. 9 shows the relationship between the rolling roll of the universal rolling method for rolling an H-section steel and the material to be rolled,
Due to the function of the universal rolling mill, the dimension that can be freely changed by the same set of roll pairs during rolling is determined by the gap 9 between the upper horizontal roll 7 and the lower horizontal roll 8 and the left and right vertical rolls 1.
Only gaps 12 and 13 between 0 and 11 are provided. Therefore, the web thickness 9 of the H-section steel and the flange thicknesses 12 and 13 can be changed, but the web inner width IW must be constant. As a result, the thickness of the H-shaped steel product 9
In rolling different series, if the left and right flange thicknesses 12 and 13 are changed, the total web height OW of the web inner width IW and the left and right flange thicknesses 12 and 13 must be changed to various dimensions. Will not be.

That is, in the H-section steel rolled by the conventional rolling method, as shown in FIG. 10, the web inner width IW is constant, and the web height OW1 changes to OW2 when the flange thickness Tf1 changes to Tf2. A series of products with a constant web inner width. If an H-shape steel product series with a constant web height is to be manufactured by a conventional rolling method using a universal rolling mill, depending on the change in the inner width of the web, the vertical rolling in all the steps of rough rolling to intermediate rolling to finish rolling is performed. It is necessary to prepare a large part of the horizontal rolls, which requires a large number of rolls and frequent roll change operations, resulting in a remarkable production cost. Impossible.

[0006] As a method of solving such a drawback in the conventional method, Japanese Patent Application Laid-Open Nos. 4-288901 and 4-288902 are well known. FIG. 4 is a schematic view showing a rolling means disclosed in Japanese Patent Application Laid-Open No. 4-288901.
In the figure, a horizontal roll 11 of an intermediate universal rolling mill is shown.
h, a first step of forming excess material at the root of the flange and the web and at both ends of the web by the vertical roll 11v,
In a rolling mill equipped with a pair of roll width-adjustable rolling rolls 12, the rolling roll width is set to be larger than the web inner width in the above process, and the material to be rolled is rolled by rolling the material to be rolled. The second step in which the excess thickness is reduced to the same thickness as the central portion of the web to convert most of the reduced area to increase the inner width of the web, and further, the web of the material to be rolled is rolled by the roll 13 having a constant roll body width. A predetermined web height is obtained by repeating the three steps of the third step of forming excess material at both ends of the web. FIG. 5 is a schematic diagram of JP-A-4-288902. In this method, first, a horizontal roll 1 of an intermediate universal rolling mill is used.
1h, a first step of forming excess material at the root portion of the flange and the web and both ends of the web by the vertical rolls 11v, and then the inside of the web in the above-described process was performed by a rolling mill equipped with a pair of rolling rolls 12 capable of adjusting the roll width. By setting the rolling roll width larger than the width and rolling the material to be rolled, the inner width of the web is expanded, and the excess thickness is reduced to the same thickness as the central portion of the web in the above process, and most of the reduced area of the web is reduced. A predetermined web height can be obtained by repeating the two steps of the second step of converting the inner width to the inner width.

In the above two conventional rolling methods, the angle formed between the inner side surface of the flange inclined outward and the surface perpendicular to the center axis of the horizontal roll of the coarse universal rolling machine after being rolled by the intermediate universal rolling mill. In the present invention, this is referred to as an out-of-flange inclination angle Θ), but it is estimated to be about 6 °, which is the same as the conventional angle. When the roll inner width of the material to be rolled having such a flange angle is increased by the roll 12 in FIG. 4 (FIG. 5), the inner width of the web per roll is determined from the geometrical relationship between the roll 12 and the flange. Even if the expansion amount ΔW of the roll is about 15 mm at the most, the front end of the flange abuts against the corner of the roll 12 and
A phenomenon occurs in which it does not bite stably. Further, if the width is increased by more than 15 mm by forcibly, the excess wall shape formed by the intermediate universal rolling mill changes abruptly. Therefore, in the first widening, as shown in FIG. A constriction occurs at 43. In addition, since the surplus shape before the web widening rolling is flat after the second time,
As shown in FIG. 6B, constriction occurs at both the corner portion 41 and the excess boundary portion 43. Hereinafter, the second constriction phenomenon will be described in detail with reference to FIG.
FIG. 7A shows a roll 1 having a flat outline 15S.
After performing the first widening with 2, the horizontal roll 1
1h or roll 13 at both ends of web
A situation in which the material to be rolled after the excess material having 8S is regenerated is rolled again by the roll 12 is shown. However, since the cross-sectional shape of the material to be rolled is substantially symmetrical with respect to the web center line Lc, only the left half cross-section is shown in FIG. From this rolling state, the plastic tensile stress σT, the temperature T in the web width direction, and the plastic tensile strain ε in the web width direction when expanding the inner width of the web using the roll 12 are further increased.
FIG. 7 shows the web width distributions C1, C2, and C3 of FIG.
(B). From this figure, it can be seen that the distribution C3 of the plastic tensile strain ε has a peak at P1 corresponding to the corner portion 41 and P2 corresponding to the excess thickness boundary portion 43, and constriction occurs at this portion. Therefore, in the above two rolling methods, it is not possible to expect a web height larger than 15 mm per widening rolling from both sides of the rollability of the material to be rolled and the web constriction.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a method for rolling a section steel having a flange capable of freely adjusting the height of a web efficiently without increasing the number of rolls without causing the above problems. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a rough rolling process, an intermediate rolling process, and a finishing rolling process. In a method of rolling a section steel having a flange by a rolling equipment provided with a double rolling mill having a body width variable mechanism, and using a universal rolling mill in the intermediate rolling step, the both ends of the web of the material to be rolled The outer line of the cross section in the width direction forms a surplus portion formed of a combination of a plurality of arc portions having different radii of curvature, and the flange outer inclination angle Θ of the material to be rolled is set to the target widening amount Δ of the web height.
The following expression represented by W, the flange width F of the material to be rolled, the web thickness tw, and the excess wall height hr: sin ⁻¹ (ΔW / (F−tw)) ≦ Θ ≦ tan ⁻¹ (ΔW
/ 2hr), and the outer shape of the cross-section in the body width direction of the excess pressure lower surface is formed into a shape obtained by combining a plurality of arc portions having different radii of curvature. A flange having a width set to be larger than a body width of a horizontal roll of the universal rolling mill, and performing at least one wide-width rolling of the web height while reducing the excess wall portion by the roll of the double rolling mill; A method of rolling a section steel, and after performing widening rolling of the web height by the double rolling mill, pressing the flange outer surface with a pair of left and right vertical rollers, correcting the flange angle, and then performing the finish rolling. In a method for rolling a shaped steel having

[0010]

The basic rolling process of the present invention is shown in FIG.
As shown in (b), the rough rolling mill BD in the rough rolling step I for supplying the beam blank 4,
The universal rolling mill RU of the intermediate rolling step II for rolling into a shape and providing extra portions 18 at both ends of the web 2a and forming the outer inclination angle の of the flange 1a to an appropriate value, the width (Fcos Θ) of the flange 1a. The edger rolling mill E for forming, the double rolling mill 2Hi having a function of adjusting the height of the web which is installed close to the intermediate rolling process II, and the finishing universal rolling mill FU of the finishing rolling process III for rolling to the final product. Be composed.

First, the first problem in the rolling method described in the above-mentioned Japanese Patent Application Laid-Open Nos. 4-288901 and 4-288902, that is, a book for preventing a biting failure of a material to be rolled during widening. The invention will be described. FIG.
(A) and (b) are cross-sectional shapes in the width direction at both ends of the web 2a in the universal rolling mill RU having a radius of curvature R1.
The situation in the case where the web height of the material to be rolled, which is formed by appropriately forming the outer slope の of the flange 1a while providing the surplus portion 18 composed of a combination of the arc portions of the RN, is widened by the double rolling mill 2Hi. FIG. In the present invention, the range of the flange angle Θ corresponding to the desired widening amount ΔW is defined by the following (1).
Give by expression.

Sin ⁻¹ (ΔW / (F−tw)) ≦ Θ ≦ tan ⁻¹ (ΔW / 2 hr) (1) where F is the flange width, tw is the web thickness, and hr is the excess wall height. . Sin ^-1 (ΔW / (F-tw)) which gives the lower limit value of the out-of-flange inclination angle で in the equation (1) is shown in FIG.
As shown in (a), the roll R of the double rolling mill 2Hi
2Hi defines that the outer surface starts contact from the point A at the forefront of the inner surface of the flange. If the outer flange inclination angle 以上 is equal to or greater than this lower limit, the material to be rolled collides with the flange and becomes jammed. There is no problem of not being there. Since the corner radius of the roll R2Hi corresponds to the corner radius of the material to be rolled, even if the material is shifted left and right within the range of the corner radius, there is no problem in the biting of the material to be rolled into the roll. Further, tan ^-1 (ΔW / 2hr) which gives the upper limit value of the flange inclination angle は is the double rolling mill 2H
This defines that the i-roll R2Hi starts to contact the flange at a point B which is separated from the web surface by the excess height hr, and when Θ is larger than this, the web is stretched in the width direction via the flange. The force FW becomes extremely small, and the desired widening cannot be performed.

Further, when the rolled material having a considerably large flange angle after the widening rolling is finish-rolled,
In order to improve the workability of the material to be rolled into the finishing universal rolling mill FU, a flange angle correction shown by a broken line in FIG. 1A is provided on the rear surface of the double rolling mill 2Hi or on the front surface of the finishing universal rolling mill FU. It is also effective to form a desired flange angle in advance by installing a vertical roller VR and pressing the flange.

Next, the second problem of the conventional means, that is, the means of the present invention for preventing the web from constricting in the material to be rolled during large-width rolling will be described. Various web widening rolling methods using the double rolling mill 2Hi are conceivable.
After the first web widening rolling by the roll R2Hi of the heavy rolling mill 2Hi is completed, the intermediate universal rolling mill RU
The gap between the vertical roll 2V and the side surface of the horizontal roll 2H is set so that the flange 1a of the material to be rolled after the widening rolling is not reduced, and the horizontal roll 2H lowers the web 2a of the material to be rolled. An example of a case where the second web widening rolling is performed after providing a surplus portion having a smooth outer shape line 18S 'will be described. FIGS. 3A and 3B show the relationship between the roll R2Hi and the material to be rolled during the second web widening rolling,
Roll R2Hi Distribution of plastic tensile stress σT, material temperature T and plastic tensile strain ε in the web width direction when the web height of the material to be rolled is increased again, that is, curves C4, C5, and C
6 was shown. The surplus pressure lower surface 15S 'has a different radius of curvature R.
Since the first widening is performed using the roll R2Hi of the double rolling mill 2Hi in which the arc portions of 1 ′ to RN ′ are combined, the excess material of the material to be rolled before the second widening rolling is performed. The outline 18S 'of the part is much smoother than in the case of the conventional means. Therefore, the plastic tensile stress σT in the web width direction increases smoothly as shown by the curve C4. On the other hand, the material temperature T becomes higher at the corners of the curve C5. In general, since the steel material is more likely to be deformed as the tensile stress is larger and the temperature is higher, the resulting plastic tensile strain ε in the web width direction has a substantially uniform distribution without a local peak as shown by a curve 6, and The constriction is suppressed. The above-described rolling can be repeated several times in consideration of the desired temperature of the material to be rolled in the finish rolling step 3, and no constriction occurs in this case as well.

[0015]

EXAMPLE In the case where the web height of an H-section steel having a web height of 6 mm and a flange width of 200 mm is increased, a comparison is made between the case where the rolling method of the above-mentioned publication is used and the case where the present invention is applied. Demonstrate the effectiveness of the present invention.

First, in the above-mentioned conventional means, the distance is 15 m per time.
The widening rolling of m is the limit, and when wider rolling is performed, the rollability of the material to be rolled becomes extremely poor, and the widening rolling of 15 mm is the limit for stable operation. Further, as shown in FIG. 4 or FIG. 5, the repetitive rolling of excess wall forming → web widening → web widening → excess wall forming → web widening was performed, and the widening amount in the first web widening rolling was up to 15 mm. Although it was possible, it was found that when the web was widened by 15 mm in the second web widening rolling, constriction occurred at the corner of the material to be rolled, and it was found that the limit was about 10 mm after the second web widening rolling. Further, since the temperature of the material to be rolled was remarkably reduced, further repeated rolling was impossible. Therefore, the critical width of the conventional rolling method is 1
15mm at the time, 10mm each at 2 and 3 times, 3 in total
It is about 5 mm.

On the other hand, in the present invention, widening rolling of about 30 mm per time was possible. The conditions in this case are as follows: target width of web height ΔW = 30 mm, flange width F of the material to be rolled F = 200 mm, web thickness tw = 6 mm,
Assuming that the surplus wall height is hr = 25 mm, the outer flange inclination angle に よ り is set in the range of 9 ° ≦ Θ ≦ 30 ° according to the above equation (1). That is, according to the present invention, the biting property is improved by optimizing the inclination angle 外 outside the flange, and the necking is suppressed by making the surplus portion of the material to be rolled before the widening rolling into a smooth shape.

Further, in the present invention, since the cross-sectional shape of the lower surface of the excess pressure of the roll of the double rolling mill is optimized, the same widening amount as the first time can be realized in the second and subsequent web widening rolling. Repeated rolling of meat forming → web widening → web widening → excess wall forming → web widening
A large web widening of m / times × 3 times = 90 mm was possible. The product obtained by the above rolling had good quality.

[0019]

By applying the present invention to a process for producing a section steel having a flange having a web height widening step by a double rolling mill, an extremely large web widening can be achieved by using a double rolling mill. There is no web constriction even if you go,
Finish rolling can be performed on a product having a good web thickness distribution, and an H-shaped steel product series having an arbitrary web height can be produced with good quality and an extremely small number of rolls.

[Brief description of the drawings]

1 (a) and 1 (b) are schematic views of a method for rolling an H-section steel according to the present invention.

FIG. 2 is a schematic diagram illustrating a method for preventing a biting failure of a material to be rolled during web widening rolling according to the present invention.

FIG. 3A is an explanatory view showing a relationship between a roll and a material to be rolled at the time of web widening rolling according to the present invention, and FIG. 3B is a diagram showing tensile stress, temperature, and temperature in the web width direction at the time of web widening rolling according to the present invention. FIG. 2 is a schematic view of distribution of tensile plastic strain in a cross section of a rolled material.

FIG. 4 shows (a), (b), (c), (d), (e),
(F), (g) is explanatory drawing of the conventional rolling method.

5 (a), (b), (c), (d), (e),
(F), (g) is explanatory drawing of the conventional rolling method.

FIGS. 6A and 6B are explanatory diagrams of a portion where web constriction occurs.

FIG. 7 (a) is an explanatory view showing a relationship between a roll and a material to be rolled at the time of web widening rolling according to the conventional method, and FIG. 7 (b) is a tensile stress in the web width direction at the time of web widening rolling according to the conventional method;
FIG. 2 is a schematic diagram of distribution of temperature and tensile plastic strain in a cross section of a material to be rolled.

FIGS. 8A and 8B are explanatory views of a typical example of a conventional row of H-section rolling mills and cross-sectional shapes of materials to be rolled which have been rolled by rough, intermediate and finishing rolling mills.

FIG. 9 is a functional explanatory view of an H-section steel universal rolling mill.

FIG. 10 is an explanatory diagram of a product series having a constant web inner width.

[Description of Signs] I: Rough rolling process II: Intermediate rolling process III: Finish rolling process 4: Beam blank BD: Rough rolling mill 1a: Flange 2a: Web 18: Surplus portion Θ: Flange inclination angle RU: Intermediate universal rolling 2H: Horizontal roll 2V: Vertical roll E: Edger rolling mill 2Hi: Double rolling mill R2Hi: Roll of double rolling mill FU: Finishing universal rolling mill VR: Vertical roller for correcting flange angle

Continuation of the front page (56) References JP-A-7-284801 (JP, A) JP-A-8-71602 (JP, A) JP-B 8-32330 (JP, B2) JP-B 54-29416 (JP) , B2) Jpn. 2541328 (JP, B2) Patent 2541326 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1/08

Claims (2)

(57) [Claims] 1. A double body having a body width variable mechanism in the vicinity of an intermediate rolling step between an intermediate rolling step and a finishing rolling step of a section steel rolling process comprising a rough rolling step, an intermediate rolling step, and a finishing rolling step. In a method of rolling a section steel having a flange by a rolling equipment provided with a rolling mill, the outer shape of the cross section in the width direction at both ends of the web of the material to be rolled using a universal rolling mill in the intermediate rolling step has a radius of curvature. In addition to forming a surplus portion formed by combining a plurality of different arc portions, the inclination angle 外 outside the flange of the material to be rolled is set to the target width ΔW of the web height, the flange width F of the material to be rolled, and the web thickness tw. , And the following formula expressed by the surplus height hr: sin ⁻¹ (ΔW / (F−tw)) ≦ Θ ≦ tan ⁻¹ (ΔW
/ 2hr), and the outer shape of the cross-section in the body width direction of the excess pressure lower surface is formed into a shape obtained by combining a plurality of arc portions having different radii of curvature. The width is set to be larger than the body width of the horizontal roll of the universal rolling mill, and at least one wide-width rolling of the web height is performed while reducing the excess wall portion by the roll of the double rolling mill. A method for rolling a shaped steel having a flange. 2. The method according to claim 1, wherein after performing a widening rolling of the web height by a double rolling mill, the flange outer surface is pressed by a pair of right and left vertical rollers to correct the flange angle, and then finish rolling is performed. A method for rolling a shaped steel having a flange according to claim 1.