JPH07214102A - Free rolling method of shape steel with flange - Google Patents

Abstract

PURPOSE:To obtain a rolling method for efficiently and freely separately manufacturing especially the web height of H-shape steel without defect in shape by an inclined roll method. CONSTITUTION:In a rolling method for widening the web height by providing inclined rolls between an intermediate rolling stage and the finish rolling stage of the rolling process of shape steel with flanges, a thickness distribution which is symmetrical to the center line and continuously decreased toward the middle part of the web from connecting parts of a web 2a with the flanges 1a is imparted with the horizontal rolls 2H of a universal mill 2-1. By widening the web height while drafting excess metal parts 18 with the inclined rolls 15m, 15m', 16m, 16m' whose excess metal drafting surfaces are a smooth shape which circular arcs having different radii of curvature are combined in a cross- sectional shape in the width direction of barrel, the distribution of tensile plastic strain in the width direction of the web is approximately uniformed and the necking of the web at the time of heavy-duty widening rolling is suppressed.

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 and flexibly forming the web height of an H-section steel without any defect in shape.

[0002]

2. Description of the Related Art Shaped steel currently manufactured by rolling is
The feature is that the number of varieties and sizes is very large, and with the diversification of customer needs, there is an increasing tendency for more varieties and sizes. In order to manufacture these various types and sizes of shaped steels by the conventional rolling method, a large number of dedicated rolling rolls and dedicated guides corresponding to the shaped steels are required, and the number of times of roll / guide reassembly increases. Therefore, time loss increases and productivity is significantly impaired.

As a concrete example of this, the case of H-section steel will be described below. FIG. 7 (a) shows a typical example of a conventional H-shaped steel rolling equipment train, but one breakdown rolling mill 1
(BD) followed by a single or multiple RU-E group 2 consisting of a 4-roll universal rolling mill (RU) and an edger rolling mill (E), and a finishing 4-roll universal rolling mill 3 (FU). ing.

FIG. 7 (b) shows the respective shapes 4, 5, of the rolled material formed by the rolling mills 1, 2, 3 in FIG. 7 (a).
6 is shown. FIG. 8 shows the relationship between the rolling roll of the universal rolling method for rolling H-section steel and the material to be rolled,
Due to the function of the universal rolling mill, the size 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 between the left and right vertical rolls 10 and 11. Only the gaps 12 and 13 are provided. Therefore, the web thickness 9 and the flange thicknesses 12 and 13 of the H-section steel can be changed, but the web inner width IW must be constant. As a result, when rolling series with different thickness 9 of H-section steel products, left and right flange thicknesses of 1
If 2, 3 are changed, naturally the web height OW, which is the total of the inner web width IW and the left and right flange thicknesses 12, 13, must be changed to various dimensions.

That is, in the H-section steel rolled by the conventional rolling method, the inner web width IW is constant as shown in FIG.
When the flange thickness Tf1 is changed to Tf2, the web height OW1 is changed to OW2, which is a so-called constant web inner width product series. If an H-shaped steel product series with a constant web height is to be manufactured by the conventional rolling method using a universal rolling machine, the upper and lower parts in all steps of rough rolling, intermediate rolling, and finish rolling may be changed according to the change in the inner width of the web. Since most of the horizontal rolls have to be prepared, a large number of rolls have to be prepared, and frequent roll recombining work has to be carried out, which causes a significant increase in manufacturing cost, so it is practically impossible to adopt this method. It is impossible.

The applicant of the present application has found that as one method for solving the above-mentioned drawbacks in the conventional method, Japanese Patent Publication No. 3-1212.
The rolling method of a profile having a flange by the skew roll method of Japanese Patent No. 2 has been proposed previously. As shown in FIGS. 4 (a) and 4 (b), the characteristic of the "oblique roll type rolling method" is that two upper and lower skew rolls 15, 15 'and 1 are provided.
The outer surfaces 19, 19 ', 20, 20' of 6, 16 'are in contact with the inner flanges 21, 22 of the material 17 and the roll axis S
Is θ _H with respect to the plane perpendicular to the rolling direction in the plane parallel to the rolling direction and θ _V with respect to the plane parallel to the rolling direction in the plane perpendicular to the rolling direction, By pressing down the excess thickness portion 18 formed thicker than the central portion of the web, the material of the pressed down portion is made to flow in the width direction, and the web can be expanded in the width direction without causing any wave of the web. Is to have.

FIG. 5 (a) shows an example in which the rolling mill 14 adopting this "oblique roll type rolling method" is incorporated in a hot rolling equipment train for H-section steel. By combining an intermediate universal rolling mill (RU-E) 2, an oblique roll type rolling mill (SS) 14 and a finishing rolling mill (FU) 3 in which the horizontal width of the horizontal roll is variable in the figure, It is basically possible to manufacture the “H-shaped steel product series with a constant web height (OW)” shown in FIG. 3C with a small number of rolls.

Further, referring to FIGS. 5 (a), 5 (b) and 5 (c), an example in which the oblique roll method is applied to the production of an H-section steel product series having a constant web height (OW) will be described in detail. First, in the intermediate universal rolling mill group 2 (RU-E), the beam blank 4 supplied from the rough rolling mill 1 (BD) is shaped up to a cross-sectional shape 25 having extra thickness portions 18 at both ends of the web. That is, recesses are provided on the left and right peripheral surfaces of the upper and lower horizontal rolls of the intermediate universal rolling mill (RU), and the recesses are rolled so as to fill the steel material, and a cross-sectional shape 25 is formed. Cross-sectional shape 25 molded in this way
The number of types is not limited. That is, since the material is rolled and shaped by the universal rolling mill in the intermediate process, the web thickness and the flange thickness can be freely changed, and the required number of different cross-sectional shapes can be shaped according to the product series. . The inner web width IW1 is constant and the web height OW1 is not always constant. The cross-sectional shape 25 formed by the intermediate universal rolling mill group 2 or the rolling material formed in the cross-sectional shape in which the web thickness and the flange thickness are further different as necessary is sent to the skew roll type rolling mill 14 (SS). . Each of these rolled materials has a cross-sectional shape 27 that is widened and rolled by the skew roll rolling mill 14 (SS) to have various necessary internal web width dimensions IW2 according to the product series.

The cross-sectional shape 27 produced by the oblique roll type rolling mill 14 (SS) has various web inner widths IW4 according to the product series by the finishing rolling mill 3 (FU) in which the body width of the horizontal roll is variable. The product 29 is shaped and rolled into a cross-sectional shape 28 having a constant web height OW and a web inner width IW6 according to the product series. In addition, the product 31 having the largest flange thickness and the smallest web inner width in the product series is not subjected to web widening by the oblique roll type rolling mill 14 (SS), but finish rolling in which the body width of the horizontal roll is variable. It is possible to manufacture by directly using the cross-sectional shape 25 of the intermediate universal rolling mill group 2 in the rolling mill 3 (FU). However, in this case, the product web inner width IW
The inner web width IW3 of the sectional shape 30 corresponding to 5 and the inner web width IW of the sectional shape 25 of the intermediate universal rolling mill group 2
W1 is set to a mutually compatible value.

As described above, the oblique roll type rolling method of Japanese Patent Publication No. 3-42122 has a good web widening function, but a large web widening is required in order to manufacture products of different series from the same set of rolls. If it is attempted, (a) a large amount of excess thickness is generated in order to prevent a local thickness reduction (hereinafter referred to as a constriction) at the corner R portion 41 and the boundary 43 between the excess thickness portion and the central portion 42 as shown in FIG. (B) Since the amount of surplus is the same for each size of the profile, if the web height is not widened, a very large surplus must be reduced by the finishing mill. (C) The finish rolling mill must have a structure in which the body width of the horizontal roll can be changed in response to changes in the web width of the profile, so the rigidity and strength of the roll are lower than those of conventional integrated rolls. Have to There, for three reasons above, the problem of excess thickness to the product web remains occurs.

[0011]

SUMMARY OF THE INVENTION In order to manufacture products of different series from the same set of rolls without causing the problems described above, the present invention does not increase the amount of surplus and performs skewing. An object of the present invention is to provide a method for performing large web widening on a roll rolling mill.

[0012]

The gist of the present invention is to provide a central axis line between the intermediate rolling step and the finish rolling step of a shaped steel rolling process including a rough rolling step, an intermediate rolling step and a finish rolling step. Is a pair of left and right skew rolls having a predetermined angle θ _H with respect to a plane that is horizontal to the rolling direction and perpendicular to the rolling direction, and is arranged inside the upper and lower flanges of the material to be rolled. In the rolling method of the shaped steel for widening the web height while reducing the surplus of the web both ends, in the web of the material to be rolled in the intermediate rolling step, the web center from the joint between the web and the flange is symmetrical. After the thickness distribution that decreases continuously toward the section is applied, the web height is widened by the skew roll having a shape in which the pressure lower surface of the surplus part is a combination of a plurality of arcs with different radii of curvature. Has a flange characterized by There is a method of rolling rolled steel.

[0013]

The basic rolling process of the present invention is as shown in FIG.
As shown in (b), a rough rolling machine 1 (BD) for supplying a beam blank 4, the beam blank 4 is rolled into a substantially H shape, and the web 2a is bilaterally symmetric and the web center and the flange are joined to the center of the web. Rolling mill 2-1 that gives a thickness distribution that continuously decreases toward the edge
(RU), an edger rolling mill 2-2 (E) for forming the width F of the flange portion 1a, and a skew roll rolling mill 14 installed after the intermediate rolling process and having a function of adjusting the web height.
(SS), and finishing mill 3 for rolling to the final product
(FU).

Next, a description will be given of a method of widening the width of the web by using the present rolling process without increasing the amount of extra thickness. In FIG. 3A, a surplus portion 18 in which a ridge line is a combination of a plurality of arcs having different radii of curvature is shown in the oblique rolls 15 and 1 with flat surplus pressure lower surfaces 15S and 15S '.
The profile 17 (showing a half-section) and the skew roll 15 at a certain stage in the process of widening the web while pressing down at 5 ',
The relationship with 15 '(one side) is shown. At this stage,
The change in web thickness at the corner R portion 41 of the shape member 17 and the boundary portion 45 between the pressed portion and the unpressed portion of the excess thickness portion is
It becomes sharper than the surplus portion 18 before the reduction.

From such a rolling step, the tensile stress σ _T in the web width direction, the material temperature T, and the tensile plastic strain ε in the web width direction when the web of the profile 17 is further widened and rolled are shown in FIG. )Pointing out toungue. Tensile stress in web width direction σ _T
Is distributed as shown by the curve C1 and sharply increases at the portion where the web thickness sharply decreases. Further, the material temperature T is distributed as shown by the curve C2 and becomes higher as it approaches the corner R portion 41. Since the material tends to deform as the tensile stress increases and as the temperature increases, the tensile plastic strain ε in the web width direction in this case has peaks at P1 and P2 as shown by the curve C3, and a very small value at the center of the web. Becomes Generally, in a tensile test of a material, a constriction phenomenon occurs above a certain strain, but also in the above-described widening rolling, a constriction also occurs in a portion where the tensile plastic strain in the web width direction is concentrated. Therefore, in such a state, if an extremely large width expansion is performed without increasing the amount of extra thickness (that is, the tensile stress σ _T in the web width direction increases, and the tensile plastic strain ε in the web width direction increases), The tensile plastic strain at P1 and P2 becomes extremely large, and the constriction at the corner R portion 41 and the boundary portion 45 becomes further large.

Therefore, in the present invention, as shown in FIG. 2A, in the intermediate rolling step, the web 2a of the material to be rolled is symmetrical with respect to the web 2a, and the connecting portion Q ₁ , between the web 2a and the flange 1a,
A thickness distribution that continuously decreases from Q ₂ toward the central portion W _c of the web is provided, and the skew rolls 15m, 15
By forming the outer shape in the cylinder width direction of the surplus pressure lower surfaces 15mS, 15mS 'of m'to be a combination of arcs having different radii of curvature, the shape of the web thickness at the time of widening rolling can be changed to the radius of curvature R ₁ ,
R _2, R _3, ..., by a smooth shape that combines an arc R _N, is to prevent the constriction of the foregoing. Note that FIG. 2A shows only the left side with respect to the web central portion W _c of the symmetrical H-shaped steel, and the right side is omitted, but the web thickness distribution of the right half and the skew of the right side are shown. Needless to say, the rolls 16m and 16m 'have the same structure as the left side.

Distributions of the tensile stress σ _T in the web width direction, the material temperature T, and the tensile plastic strain ε in the web width direction in the case of further widening rolling from the rolling stage shown in FIG.
It is shown in FIG. In the case of the smooth web thickness distribution as shown in FIG. 2A, the tensile stress σ _{T in the} web width direction smoothly increases from the material corner R portion to the web central portion as shown by the curve C4. Further, the material temperature T becomes higher at the corner R portion as shown by the curve C5. Therefore, the tensile plastic strain .epsilon. In the web width direction has a substantially uniform distribution without exhibiting a local peak as shown by the curve C6. That is, the constriction of the web is suppressed, and the width of the web is increased by the amount that the central portion of the web is widened in the width direction. Further, since the tensile plastic strain ε does not have a peak, the web is substantially uniformly widened even if the widening amount is increased without increasing the excess thickness.

[0018]

[Example] H-shaped member having a web height of 600 mm and a flange width of 200 mm and H-shaped member having a web height of 700 mm and a flange width of 200 mm
The effectiveness of the present invention is demonstrated by comparing the case where the conventional method shown in FIG. 3 is used and the case where the present invention shown in FIG. .

Table 1 shows the case where the conventional method is applied. In order to keep the remaining amount of surplus within the allowable value, the sectional area of the surplus was set to 50% of the maximum required amount. Therefore, the constriction during the large widening rolling was extremely large and remained after the finish rolling.

[0020]

[Table 1]

On the other hand, Table 2 shows the case where the present invention is applied. Even if rolling is carried out under the same conditions as above, due to the effect of uniformizing the tensile plastic strain distribution in the web width direction, the constriction is an allowable value. It was confirmed that a product with good dimensional accuracy was obtained.

[0022]

[Table 2]

[0023]

By applying the present invention to a manufacturing process of a profile having a flange by a skew roll system, no web constriction occurs even if an extremely large web widening is performed by the skew roll, and the web is Even if the width is not widened, finish rolling can be performed on a product having a good web thickness distribution, and an H-shaped product series having an arbitrary web height can be manufactured with good quality and an extremely small number of rolls.

[Brief description of drawings]

1A and 1B are schematic views of a rolling method of an H-shaped material according to the present invention.

FIG. 2A is an explanatory view showing a relationship between a roll and a profile during web widening rolling by the skew roll of the present invention. (B):
FIG. 3 is a schematic view of the tensile stress in the web width direction, the material temperature, and the distribution of tensile plastic strain in the web width direction in the cross section of the profile during the web widening rolling with the skew roll of the present invention.

FIG. 3A is an explanatory view showing a relationship between a roll and a profile at the time of web widening rolling with a conventional skew roll. (B): A schematic view of the tensile stress in the web width direction, the material temperature, and the distribution of tensile plastic strain in the web width direction in the cross section of the profile during the web widening rolling with the conventional skew rolls.

4 (a) and 4 (b) are explanatory views of a skew roll rolling method.

5 (a) and 5 (b): Functional explanatory diagrams of an apparatus and a rolling machine for skew roll rolling. (C): Schematic drawing of the product by the oblique roll type rolling method.

FIG. 6 is an explanatory diagram of web constriction.

7 (a) and 7 (b): Explanatory views of a typical example of a conventional H-shaped material rolling device train and cross-sectional shapes of materials rolled by rough, intermediate, and finishing rolling mills.

FIG. 8 is a functional explanatory view of a universal rolling mill based on a relationship between a universal rolling roll for rolling an H-shaped material and a material to be rolled.

FIG. 9 is an explanatory diagram of a product series with a constant web inner width.

[Explanation of symbols]

 1 Breakdown rolling mill 2 RU-E group 2-1 Intermediate universal rolling mill 2-2 Edger rolling mill 3 Finishing universal rolling mill 4-6 Rolled material 14 Oblique roll type rolling mill 15, 15 'Oblique roll (conventional) 16, 16 'Oblique Roll (Conventional) 15m, 15m' Oblique Roll (Invention) 16m, 16m 'Oblique Roll (Invention) 17 Shaped Material 18 Extra Thickness

Claims (1)

[Claims] 1. A center axis of a shaped steel rolling process comprising a rough rolling process, an intermediate rolling process, and a finish rolling process between the intermediate rolling process and the finish rolling process is in a plane horizontal to the rolling direction, and A pair of left and right skew rolls having a predetermined angle θ _H with respect to a plane perpendicular to the rolling direction are arranged inside the upper and lower flanges of the material to be rolled, and the skew rolls are used to reduce the excess thickness at both end portions of the web. In the rolling method of the shaped steel for widening the web height, in the web of the material to be rolled in the intermediate rolling step, the thickness which is symmetrical and decreases continuously from the connecting portion between the web and the flange toward the web central portion. After the distribution, the web height is widened by a skew roll having a cross-sectional shape in the body width direction of the surplus portion pressure lower surface that is a combination of a plurality of arcs with different radii of curvature. Of shaped steel with flange Standing rolling method.