JP3065877B2 - Rough rolling method for H-shaped steel slab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a steel slab having a rectangular cross section as a raw material, through a coarse steel slab having a dog bone type cross section (hereinafter referred to as "dog bone material"), and particularly having a large flange thickness. Sectional steel (hereinafter, referred to as “extremely thick H-section steel”) and H-section steel with a large web height and flange width (hereinafter, “large H-section steel”)
(Hereinafter referred to as "shape steel").

[0002]

2. Description of the Related Art Conventionally, for example, a rolling process for manufacturing an H-section steel 62 shown in FIG. A first intermediate coarse universal rolling mill 2a and a first intermediate coarse universal rolling mill 2 that are in charge of rolling from the piece 61 to the H-section steel 62;
a from the edging rolling mill 2b, the second intermediate coarse universal rolling mill 3a, and the edging rolling mill 3b provided close to the second intermediate coarse universal rolling mill 3a, and the finishing universal rolling mill 4. It is configured.

[0003] In recent years, as a rolling material for H-section steel, a beam blank formed by continuous casting has been frequently used in place of a beam blank formed from a steel ingot by soaking and bulk rolling, in order to omit processes and improve quality. It became so. Rough molding technology for intermediate coarse steel slabs using rectangular cross-section steel slabs
The techniques disclosed in JP-A-8-19361, JP-B-58-37042 or JP-A-2-169103, and JP-A-3-57501 as a method of forming a thick flange H-section steel are known. .

FIG. 5 shows an example of a roll-hole type arrangement of a rough double-hole type rolling mill 1 based on the above-mentioned known technique, in which a pair of upper and lower rolls is used.
Four groove molds, a groove forming hole mold G1, a flange forming hole mold G2, a groove eliminating hole mold G3, and a forming hole mold G4 are engraved on the grooves 1 and 12.
FIG. 6 shows a process of forming the intermediate coarse steel slab 61 from the rectangular cross-section steel slab 5 by the upper and lower roll pairs 11 and 12 of the rough double-hole type rolling mill 1 having such a groove.

In FIG. 6, the cross-sectional dimension of the rectangular cross-section steel piece 5 is W0 × thickness H0, and the groove forming hole type G1 is a hole type for forming a V-shaped groove 51a in the short side of the rectangular cross-section steel piece. There, a central bulging portion 21a of the top angle theta ₁ is at the center of the hole bottom width, groove 21b on both sides of the central bulging portion is engraved. The hole bottom width S1 of the grooved hole die G1 is set to be substantially equal to the thickness H0 of the rectangular cross-section steel piece 5 in order to accurately form the V-shaped groove 51a at the center of the short side of the rectangular cross-section steel piece 5. In practice, however, in order to prevent the generation of flaws due to the contact with the hole-shaped side wall 31, it is usually slightly larger than H0. The width (hereinafter, referred to as “web height”) W1 of the final finished material of the grooved hole die G1 is substantially equal to the width W0 of the steel slab having a rectangular cross section.

[0006] The V-shaped groove 51a formed in the short side portion of the rectangular section slab 5 by the groove forming groove G1 accurately guides the material to be rolled to the center of the flange forming groove G2 and its height. Directional edging rolling (hereinafter referred to as "edging rolling")
Falling and twisting at the time are prevented. Is set larger than the top angle theta ₂ of the flange generate hole-type G2 of bottom hole width S2 and the central bulging portion 22a is the top angle theta ₁ hole trough S1 and the central bulging portion 21a of the groove imparting caliber G1 . In the flange forming hole type G2, an H-section steel flange equivalent portion (hereinafter, referred to as a “flange”) 42 is divided by a central bulging portion 22a by edging rolling until the web height reaches W2, The thickness is increased, and the flange width is finished to a value B2 substantially equal to or close to the hole bottom width S2.

[0007] Next, the hole bottom width S3 is the same as the flange forming hole type G2.
Groove elimination hole type G3 set slightly larger than the hole bottom width S2 of
The web height is set to W3 by edging rolling, and the flange width of the material to be rolled formed by the flange forming hole die G2 is further expanded, so that the flange width is substantially equal to the hole bottom width S3 or a dog near the value B3. Finish to bone material 60. At the same time, the flange generate hole-type G2 top angle theta _3, which is larger than the top angle theta ₂ of the central bulging portion 22a of the central bulging portion 23a, the V-shaped groove 52a formed in the flange generate hole-type G2 The inclination is reduced to 53a to prevent the occurrence of breakage flaws on the outer surface of the flange after the next step. In the case of edging rolling from the groove forming hole die G1 to the groove eliminating hole die G3, as shown in FIG. 6, the influence of the width reduction does not reach the center in the width direction of the material to be rolled. Thickness H1, flange forming hole type in G1 grooved hole type
Web thickness H2 in G2, web thickness in G3
H3 hardly changes, and the thickness H0 of the original rectangular cross-section steel piece
be equivalent to.

Subsequently, in order to form the web and the flange of the dog bone material 60 using the forming die G4, the web is lowered and the flange is shaped to obtain a web height W × flange width B × web thickness t _WM. When the intermediate coarse steel slab 61 is obtained, the rolling in the forming die G4 is completed. At this time, the ratio t _FM / t _WM of the flange thickness t _FM and the web thickness t _{WM at} the center of the flange piece width of the intermediate crude steel piece 61 is represented by the H-section steel 62.
_Is substantially equal to the flange / web plate thickness ratio t _FP / t _WP of FIG.

The function of the groove forming hole type G1 is to form a V-shaped groove 51a on the short side of the rectangular cross section steel piece by the central bulging portion 21a, while the groove eliminating hole type G3 is the same as the flange forming hole type G2. The purpose of the present invention is to make the inclination of the V-shaped groove 52a generated by the central bulging portion 22a gentle 53a, thereby preventing the generation of breakage flaws on the outer surface of the flange after the next step. Therefore, only the flange forming groove G2 contributes to the formation of the flange, and as a result, the shape of the flange of the dog bone material 60 finished with the groove eliminating hole G3, and further, the intermediate shape finished with the forming hole G4. The shape of the flange of the crude billet 61 is greatly affected by the rolling conditions in the flange forming hole G2.

[0010] FIG. 8 shows a 1/4 cross section of an example P ₁ and ideal shape P ₂ of the flange in the shape of a dog bone material 60 the finished grooves erase caliber G3 in the conventional method. Flange thickness distribution in the width direction in the conventional method, usually as root thicker shows the distribution P ₁ such that thinner tip. In this case, when the flange thickness of the H-shaped steel 62 of the final product is relatively thin, the flange thickness in a subsequent process is large, so that the flange is a flat plate as shown in FIG. 9A.
However, when shaping the cross-section from the flange thickness of the large heavy gauge H-shaped steel and large H-beams, such as P ₁ in FIG. 8 is problematic. That is, at the time of roll forming of an extremely thick H-section steel, the first
Since the thickness of the flange thickness after the intermediate coarse universal rolling mill 2a is small, the edging amount of the flange forming hole G2 cannot be large during the rolling molding of a large H-section steel, and the flange width and the flange of the dog bone material cannot be obtained. Since the thickness is not sufficient, there has been a problem that the H-shaped steel 62 has a corner drop at the end of the flange and insufficient thickness as shown in FIG. 9B. Therefore conventionally, in order to approximate the ideal shape P _2, flange generate hole-type by increasing the width W0 of the rectangular cross-section material 5 within the facility constraints
By increasing the amount of edging rolling in G2,
It has been practiced to spread the metal to the tip of the flange and to make the thickness distribution in the flange width direction as uniform as possible.

However, in practice, the width W0 of the slab 5 that can be used is limited by the maximum opening of the upper and lower rolls of the rough double-hole type rolling mill 1, and even if the width W0 is increased without limit. Even if the amount of edging rolling in the flange forming groove G2 is increased by the above method, after the flange tip comes into contact with the groove side wall 32 of the flange forming groove G2, the restrained degree of the material to be rolled by the groove forming side wall 32 is severe. As a result, the material to be rolled is elongated in the longitudinal direction, and the efficiency of forming the flange is reduced. For this reason, continuous casting of a series of extremely thick H-beams or large H-beams has been limited to H-beams of relatively small flange thickness. As a result, with regard to other flange thick sizes, the raw steel slab produced from the steel ingot in the sizing process had to be used as the raw material.

[0012]

The problem to be solved by the present invention is to increase the cross-sectional area of a dog bone material flange and to make the thickness distribution uniform in the flange width direction by using a steel piece having a rectangular cross section. , Ultra-thick H-section steel and large H
An object of the present invention is to make it possible to manufacture thick steel flanges of a shape steel.

[0013]

A feature of the present invention is that two flange forming holes having different sizes of the central bulge are arranged,
An object of the present invention is to allow metal to flow efficiently to the tip of a flange by alternately subjecting a slab of rectangular cross section to edging rolling and changing the pressing position on the flange outer surface in each rolling process.

[0014] That is, the gist of the present invention includes a central bulging portion in the width direction central portion of the bottom of the hole, the grooved Azukaana type forming a groove on both sides of the central bulging portion and the flange generate hole-type,
In a method of shaping a slab of rectangular cross-section in the width direction and widening while interrupting a portion corresponding to an H-shaped steel flange to form a rough shaped slab having a dog-bone type cross-sectional shape, the flange forming dies are formed at respective hole bottoms. After forming a plurality of holes having substantially the same width and different heights of the central bulging portion, and applying a V-shaped groove to the short side portion of the rectangular section steel piece by the groove providing hole, the plurality of flanges are formed. Rough rolling method for rough shaped steel slab for H-section steel, which is alternately edging-rolled between forming dies, and equivalent portion of H-section steel flange by means of a center forming portion having a larger center bulging portion. The above-described section in which the width-wise central region is interrupted and rolled, and a region other than the width-wise central region of the H-shaped steel flange equivalent portion is pressed and rolled by a flange forming groove type groove having a smaller center bulging portion height. The rough rolling method for the coarse shaped billet for H-section steel described That.

Hereinafter, the present invention will be described in more detail. FIGS. 1A and 1B show the production means of the present invention, which will be described in comparison with the conventional method shown in FIG. First, in the case of the conventional method, a rectangular cross-section steel piece 5 having a width W0 and a thickness H0 is guided by a groove-provided hole die G1 at the end of the long side of the rectangular cross-section at the hole-shaped side wall 31, while the material width is almost unchanged. (Almost W1 =
In the state of (W0), the V-shaped groove 51a is formed. Subsequently, the web thickness H2 (almost
H0), a dog bone material having a flange width B2 is formed, and the V-shaped groove is loosened from the shape of 52a to the shape of 53a by lightly edging and rolling with a groove eliminating hole die G3 (at this time, the web thickness H3 (Approximately H0), resulting in a dog bone material 60 with a flange width B3). Subsequently, while reducing the web of the dog bone material 60 by the forming die G4, an intermediate coarse steel slab 61 having a web height W × flange width B × web thickness t _WM is formed. FIG. 7 shows in more detail the flange forming process in the flange forming hole type G2 in this conventional method. That is, the width and the thickness of the flange are generated by continuing the multiple-pass rolling down of the material to be rolled by the flange forming hole die G2.

On the other hand, as shown in FIG. 1 (a), the hole mold according to the present invention has the same hole bottom width as S2 and the first flange forming hole mold G2-1 having the center bulging portion height h1. And the second flange forming hole type G2-2 having a center bulging portion height h2 (h1> h2 in this example). Then, as shown in FIG. 1 (b), the induction of the V-shaped groove provided by the groove providing hole type G1 causes any one of the first flange forming hole type G2-1 and the second flange forming hole type G2-2. In the example of FIG. 1 (b), the flange width is widened by the first flange forming hole type G2-1, and alternately from the middle with the other second flange forming hole type G2-2. Edging rolling. In the example of FIG. 1B, the height of the central bulge is high (= h1). The first flange forming hole type G2-1 interrupts the central region in the width direction of the flange, and the height of the central bulge is reduced. In the low (= h2) second flange forming hole type G2-2, an area other than the central area is pressed.

By adopting the new rolling method, the flange cross-sectional area is increased as compared with the conventional method at the same edging rolling amount. The mechanism is shown in FIG.
This will be described with reference to FIG. The present invention exerts its effect especially after the flange is filled with the flange forming hole type G2-1 or G2-2 (that is, after the flange tip comes into contact with the hole type side wall 321 or 322). 2A and 2B show the edging rolling state according to the present invention, and FIG. 3 shows the edging rolling state according to the conventional method for comparison. In both cases, the edging rolling is performed with the rolling reduction e. In the method of the present invention shown in FIG. 2, the edging rolling is performed in two stages of (a) the first flange forming groove G2-1 and (b) the second flange forming groove G2-2. Is performed.
2 and 3, the cross-sectional shape of the material to be rolled is shown by a solid line and a broken line. The broken line shows the shape of the material to be rolled on the rolling-in side, and the solid line shows the shape of the material to be rolled on the rolling-out side. Also,
The hatched portions indicate the metal excluded by the roll hole mold, and the arrows indicate the direction and size of the metal excluded. The point S is a representative point (hereinafter, referred to as a “mark point”) of a portion to be a flange in the subsequent edging rolling process.

First, in the conventional method shown in FIG. 3, the flange is restrained at both ends by the hole-shaped side walls 32 and the whole is simultaneously lowered by 1 / 2e, so that the metal in the hole becomes dead metal, The metal at point S is almost 1 / 2e
Just move in the same direction. As a result, the distance between the reference point S and the outer surface of the flange hardly changes before and after the reduction (almost l ₁ = l ₂ ). That is, it becomes difficult for the metal at the reference point S to flow into the flange. To make matters worse, the flanges are edged and rolled in a state where both ends of the flanges are constrained by the grooved side walls 32, so that the flange width is suppressed and the material to be rolled extends in the direction perpendicular to the plane of the drawing. It also leads to a reduction in area.

On the other hand, according to the method of the present invention shown in FIG. 2A, first, when the central flange portion 221a interrupts the center of the flange formed by the first flange forming hole die G2-1 with the central bulging portion 221a, the peripheral metal is shown in FIG. As shown, it is removed in the flange width direction, but since both ends are constrained by the hole-shaped side walls 321, the flange width does not increase and the thickness increases. In this case, since the pressure is locally reduced at the center in the width direction of the flange,
There is little stretching in the direction perpendicular to the plane of the paper, so there is no reduction in flange cross-sectional area due to stretching. The reference point S also moves in the direction of the arrow, but the amount is small. Subsequently, the material to be rolled is introduced into the second flange forming hole mold G2-2, and only the portion other than the recess at the center of the flange of the material to be rolled is pressed by the groove of the hole shape. As a result, the distance between the flange outer surface and the rating decreases from l ₁ to l ₂ , that is, the metal near the rating S flows in the direction of the flange and increases the flange cross-sectional area unlike the conventional method. In this case, as in the conventional method, both end faces of the flange are formed with the second flange forming hole type.
Although it is constrained by the hole type side wall 322 of G2-2, the fundamental difference from the conventional method is that
Since the size of the groove provided by the central bulging portion 221a of -1 is larger than the size of the central bulging portion 222a of the second flange forming hole type G2-2, there is a gap in the central portion of the flange, and this space is provided. The metal moves to fill the gap. " As a result, "Score S moves in the direction of the flange"
Together, it is possible to suppress observed in conventional methods, "the paper to the vertical extension of the rolled material", so that the cross-sectional area of that amount flange is increased.

In the above description, the mechanism for increasing the cross-sectional area of the portion corresponding to the H-section steel flange will be described for convenience.
Taking the example of FIG. 1 (b), the first flange forming hole type G2-1
Has shown an example in which only the central region in the flange width direction is reduced and only the other region is reduced by the second flange forming hole type G2-2.
However, by performing alternating edging rolling between the two dies on one or both of the flange forming dies G2-1 and G2-2 on the entire outer surface of the flange, it is possible to use an H-shaped steel or a large H-shaped steel. It is possible to produce steel with high efficiency.

In the example of FIG. 1 (b), the distance between the first flange forming hole type G2-1 and the second flange forming hole type G2-2 is one.
Although the method of delivering the rolled material for each pass was described,
If necessary, the material to be rolled is subjected to a plurality of passes of edging rolling in one flange forming die, and then transferred to the other flange forming die, which is also within the scope of the present invention. Further, in the example of FIG. 1B, edging rolling is repeated only by the first flange forming hole die G2-1 until the rolled material flange contacts the side wall 321. This is because when the alternate edging rolling between the first flange forming die G2-1 and the second flange forming die G2-2 is performed in a state where the side flanges are in contact with the side walls 321 and 322, the edging rolling is not applied to the side walls 321 and 322. This is because the material to be rolled can be prevented from falling down during edging rolling as compared with the case where the rolling is performed in a state of contact. Therefore, if there is a means for preventing the material to be rolled from falling, the first flange forming hole G2-1
Even if the side wall 321 is not full, alternate edging rolling may be performed with the second flange forming hole die G2-2.

Further, in the example of FIG.
Although the finished G1 material is first fed into the first flange forming hole die G2-1 having a large central bulge, it may be fed first into the second flange forming hole die G2-2 having a small central bulge.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which rolling shaping of an intermediate slab billet is carried out based on the means of the present invention will be described below. Table 1 shows a comparison of the main dimensions of the flange forming hole type and the groove eliminating hole type among the roll hole types of the rough double hole type rolling mill 1 according to the method of the present invention and the conventional method. The symbols of the dimensions correspond to those shown in FIGS. 1A and 6 (the shapes of the groove forming die G1 and the forming die G4 according to the method of the present invention are exactly the same as those of the conventional method. Omitted.)

[0024]

[Table 1]

In the embodiment based on the method of the present invention, the groove eliminating hole type G3 is omitted due to the restriction of the roll body length, but the projection shape of the second flange forming hole type G2-2 is replaced by the conventional groove eliminating hole type G2-2.
As similar to that of G3, in order to prevent the generation of breakage flaws in the concave portion at the center of the outer side of the flange and obtain a predetermined flange width, the first flange forming hole type G2-1 and the second flange forming hole are used. The hole bottom width S2 = 520 mm of the mold G2-2 is matched with that of the conventional groove erasing hole mold G3, S3 = 520 mm, and the height of the central bulge is about 60 mm, h1 = 97 mm, h2 = 39 mm.
The difference.

Conventionally, the sectional dimension W0 × H0 is 1350 mm × 25
The product flange was the limit of 75 mm, at which a very thick H-section steel H400 × 400 series could be formed from a 0 mm rectangular section material through the process of FIG. On the other hand, in the present invention, the same method as in the related art is used, using the same rectangular cross-section steel slab having a cross section of 1350 mm x 250 mm as a raw material, following the formation of the intermediate coarse steel slab 61 by the rough double-hole type rolling mill 1 to which the present invention is applied. As a result of rolling to a product by a subsequent universal rolling mill, it became possible to increase the forming limit product flange thickness of the extra-thick H-section H400 × 400 series from the conventional 75 mm to 100 mm.

[0027]

According to the present invention, it is possible to increase the flange forming efficiency with respect to the same edging rolling amount using a steel slab having a rectangular cross section as a raw material.
It enables the shaping of extra-thick H-beams and large H-beams with thicker flanges, eliminating the need for complicated and costly processes that used to go through slab rolling using steel ingots as well as continuous casting. The quality improvement could be realized by using the slab as the material.

[Brief description of the drawings]

FIG. 1A is an explanatory view showing a roll of the present invention, and FIG.

FIGS. 2A and 2B are explanatory views of a flange generating mechanism in the flange generating hole mold of the present invention.

FIG. 3 is an explanatory diagram of a flange generation mechanism in a conventional flange generation hole die.

FIG. 4 is an explanatory view showing rolling equipment for a section steel having a web and a flange, such as an H section steel and an I section steel.

FIG. 5 is an explanatory view showing a part of a roll hole arrangement of a rough double hole rolling mill.

FIG. 6 is an explanatory view showing a method for producing a crude steel slab from a rectangular cross-sectional steel slab using a conventional coarse double-hole roll.

FIG. 7 is a detailed explanatory diagram of a flange generation process in the flange generation hole type G2 in the conventional method.

FIG. 8 is a schematic diagram showing a quarter cross-sectional shape of a dog bone material.

9 (a) and 9 (b) are explanatory diagrams for comparing product cross sections of a thin flange product size and a thick flange product size according to a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Coarse double-hole type rolling mill 2a 1st intermediate coarse universal rolling mill 2b 1st edging rolling mill 3a 2nd intermediate coarse universal rolling mill 3b 2nd edging rolling mill 4 Finishing universal rolling mill 5 Rectangular section steel slab 11,12 coarse Upper and lower roll pairs 21a, 22a, 23a of a double-hole type rolling mill
Central bulging portion 21b of each of G1, flange forming hole type G2 and groove erasing hole type G3 21b Grooves 31 and 32 on both sides of central bulging portion in groove providing hole type G1 Side walls of groove providing hole type G1 and flange forming hole type G2 Part 42 Flange-equivalent side surfaces of the material to be rolled in the flange forming hole type G2 51a, 52a, 53a V-shaped grooves of the material to be rolled in each of the groove forming hole type G1, the flange forming hole type G2, and the groove eliminating hole type G3. Dog bone material molded with mold G3 61 Intermediate coarse shaped billet with G4 finished hole 62 H-section steel

Continuation of the front page (56) References JP-A-3-57501 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1/08

Claims (2)

(57) [Claims] 1. A rectangular cross-section steel slab is formed in a width direction by a center bulging portion at a center portion in a width direction of a hole bottom and a groove forming hole type and a flange forming hole type having grooves formed on both sides of the center bulging portion. In a method of shaping a rough shaped steel slab having a dog bone type cross-sectional shape by performing edging rolling and widening while interrupting a portion corresponding to an H-shaped steel flange, the flange forming die has a substantially equal bottom width and a central bulge. After forming a V-shaped groove on the short side of the rectangular cross-section steel slab by the groove-providing hole, the groove is alternately formed between the plurality of flange-forming holes. A rough rolling method for a crude steel slab for H-section steel, characterized by edging rolling. 2. A flange forming hole-type central bulging portion having a larger central bulging portion interrupts and rolls a central region in the width direction of a portion corresponding to an H-shaped steel flange, and has a smaller central bulging portion height. 2. The method of claim 1, wherein a region other than the central portion in the width direction of the portion corresponding to the H-shaped steel flange is pressed and rolled by the flange forming hole-shaped groove portion. .