JP7003841B2 - Manufacturing method of H-section steel - Google Patents

Description

The present invention relates to a manufacturing method for manufacturing H-shaped steel using, for example, a slab having a rectangular cross section as a material.

In the case of manufacturing H-shaped steel, materials such as slabs and blooms extracted from the heating furnace are formed into rough-shaped materials (so-called dogbone-shaped rolled materials) by a rough rolling mill (BD), and intermediate universal rolling is performed. The machine reduces the thickness of the web and flange of the rough-shaped material, and at the same time, the edger rolling mill close to the intermediate universal rolling mill performs width rolling and forging and shaping of the end face of the flange of the material to be rolled. .. Then, the H-shaped steel product is molded by the finishing universal rolling mill.

In recent years, with the increase in size of building structures and their use in offshore structures, there has been a demand for the production of H-shaped steel products that are larger than before, and in particular, products with increased flange width and flange thickness are desired. There is. In the manufacturing process using a rectangular cross-section material such as a slab, as a technique for increasing the flange width and the flange thickness, after forming an interrupt on the upper and lower end faces (slab end faces) of the material to be rolled, the interrupt shape is formed while edging the slab end face. The technology to change the (so-called wedge method) is known.

Among these, as for the technique for increasing the flange thickness, for example, in Patent Document 1, after forming an interrupt without restraining the upper and lower ends (slab end faces) of the material to be rolled, in a state where the material does not come into contact with the hole-shaped side wall. A technique for changing the interrupt shape while edging the end face of the slab is disclosed. According to this technique, it is possible to increase the thickness of the flange according to the rolling reduction of the edging.

Further, for example, Patent Document 2 discloses a technique for changing the interrupt shape while edging the slab end face while restraining both upper and lower ends (slab end faces) of the material to be rolled. According to this technique, since both sides of the upper and lower ends of the material to be rolled are restrained and reduced, it is possible to generate a thickening at the tip of the flange to increase the wall thickness.

Japanese Unexamined Patent Publication No. 11-347601 Japanese Unexamined Patent Publication No. 7-88501

However, as disclosed in Patent Document 1, for example, when rolling is performed as a free spread without restraining the upper and lower end portions (slab end faces) of the material to be rolled, the flange width becomes large, but the thickness is the flange. There is a concern that the shape of the tip will be tapered, the thickness of the flange tip will be insufficient, sufficient molding will not be possible in the subsequent process, and a large increase in thickness will not be possible. Further, according to the study by the present inventors, even when the left and right restraints of the upper and lower end portions (slab end faces) of the material to be rolled are lowered as compared with the conventional case, the flange tip portion is similarly tapered and the thickness is insufficient. The knowledge that it will be done has been obtained.

Further, for example, as disclosed in Patent Document 2, when edging rolling is performed by restraining both sides of the upper and lower end portions (slab end faces) of the material to be rolled, the left and right flange portions are completely expanded in the hole type. Since edging rolling is performed in a restrained state, stretching of the material to be rolled in the longitudinal direction becomes dominant, the efficiency of thickening the flange portion is low, and there is a limit to the thickening of the flange. For example, even if the hole type conditions are set appropriately, rolling so that the average value of the thickness from the flange tip to the base is ½ or more of the material slab thickness cannot be performed by this technique.

Further, in a general H-shaped steel manufacturing process, it is known that the surface texture of the material to be rolled deteriorates in a wrinkle shape because the entire surface of the material to be rolled receives a compressive force during edging rolling from a slab. In addition to surface roughness caused by the steelmaking process and primary scale due to high temperature heating on the surface of the material to be rolled, when rolling molding is proceeded while the above-mentioned wrinkled surface texture is exhibited, There is a risk that uneven shapes (poor surface properties) will remain on the surface of the material to be rolled. When modeling a product size that can secure a sufficient amount of flange wall thickness by using an appropriate slab that matches the product size, it is often not a problem because a sufficient reduction rate of the flange portion can be secured, but it is smaller than the appropriate slab cross section. When modeling from a cross section or when modeling a product with a large product flange width or flange thickness, the flange thickness reduction cannot be sufficiently removed, and surface texture defects are likely to occur. This is due to the fact that in universal rolling after rough forming by hole rolling, the thickness reduction of the flange is pushed from the outer surface of the flange by the vertical roll, and in order to bring the inner surface of the flange into contact with the roll, it is rolled. This is because it is not enough to subtract the shortage in the relationship between the flange thickness of the material and the vertical roll gap.

In view of such circumstances, an object of the present invention is to provide a slab or the like by using a plurality of edging hole molds for rolling and forming the material to be rolled in the width direction in a rough rolling process using a hole mold when manufacturing H-shaped steel. When edging rolling the material and performing the process of forming the dogbone shape, the H-shape that suppresses the deterioration of the surface properties of the material to be rolled, especially the deterioration of the surface properties of the inner surface of the flange, and does not leave surface defects, etc. It is an object of the present invention to provide a method for producing an H-shaped steel capable of efficiently producing a steel product.

In order to achieve the above object, according to the present invention, an H-shaped steel manufacturing method including a rough rolling step, an intermediate rolling step, and a finish rolling step is provided, and a rolling mill performing the rough rolling step is covered with a rolling mill. A plurality of hole molds for rolling and shaping the rolled material are engraved, and the plurality of hole molds include a plurality of edging hole molds for rolling and shaping the material to be rolled in the width direction, and edging rolling by the plurality of edging hole molds. Alternatively, the material to be rolled after the completion of edging rolling is characterized by including a hole type for eliminating wrinkles in which only a part or all of the inner surface of the flange of the material to be rolled is brought into contact with the hole type roll to perform a wrinkle elimination step. A method for manufacturing H-shaped steel is provided.

In the wrinkle eliminating hole type, the length of the range W from the contact point between the vertical line in the flange thickness direction from the center of the flange outer surface to the flange inner surface to the tip of the flange inner surface is the same as the tip thickness of the flange portion. The wrinkle eliminating step may be performed by contacting at least the range W1 excluding only the tip from the tip.

The plurality of hole types are a grooved hole type that vertically groovs the widthwise end of the material to be rolled, and a grooved hole type that vertically interrupts the widthwise end of the grooved material to be rolled. One or a plurality of interrupt hole types having protrusions formed at the ends of the rolled material to form split portions, and protrusions having contact with the interrupt and sequentially bending the divided portions formed in the interrupt hole type were formed. The wrinkle eliminating step may be performed on the material to be rolled during the bending molding in the plurality of folding hole molds or after the bending molding is completed, including the plurality of folding hole molds.

The plurality of fold hole molds are composed of a first fold hole mold and a second fold hole mold in which the material to be rolled is sequentially bent and shaped, and the wrinkle eliminating step is performed after the first fold hole mold is used for bending molding. Or, it may be performed on the material to be rolled after the bending molding in the second folding hole type.

The angle of the tip of the protrusion formed in the second bent hole shape may be 180 °.

The plurality of hole types include the interrupt hole type, the bent hole type, and the flat forming hole type in which flat rolling is performed on the material to be rolled that has passed through the wrinkle eliminating hole type. , The inner surface of the flange of the material to be rolled may be configured so as not to come into contact with the hole-shaped roll.

At least one or more of the edging hole types may be engraved inside the hole type for eliminating wrinkles.

According to the present invention, in a rough rolling process using a hole mold for manufacturing H-section steel, edging rolling is performed on a material such as a slab by a plurality of edging hole molds for rolling and forming the material to be rolled in the width direction. , When performing the process of forming the dogbone shape, it suppresses the deterioration of the surface quality of the material to be rolled, especially the deterioration of the surface quality of the inner surface of the flange, and efficiently manufactures H-shaped steel products that do not leave surface defects. can do.

It is a schematic explanatory drawing about the production line of H-shaped steel. It is a schematic explanatory drawing of the 1st hole type. It is a schematic explanatory drawing of the 2nd hole type. It is a schematic explanatory drawing of the 3rd hole type. It is a schematic explanatory drawing of the 4th hole type. It is a schematic explanatory drawing of the 5th hole type (flat type hole type). It is a schematic explanatory drawing which shows the structure of the hole type for wrinkle elimination which concerns on this embodiment. It is a schematic diagram which shows the modification of the hole type for wrinkle elimination. It is a schematic explanatory drawing which shows an example of the conventional edging rolling method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(Outline of production line)
FIG. 1 is an explanatory diagram of an H-section steel production line T including the rolling equipment 1 according to the present embodiment. As shown in FIG. 1, a heating furnace 2, a sizing mill 3, a rough rolling mill 4, an intermediate universal rolling mill 5, and a finishing universal rolling mill 8 are arranged in order from the upstream side on the production line T. Further, an edger rolling mill 9 is provided in the vicinity of the intermediate universal rolling mill 5. In the following, for the sake of explanation, the steel materials in the production line T are collectively referred to as “rolled material A”, and the shape may be appropriately illustrated by using broken lines, diagonal lines, or the like in each drawing.

As shown in FIG. 1, in the production line T, the material A to be rolled, such as the slab 11 extracted from the heating furnace 2, is roughly rolled in the sizing mill 3 and the rough rolling mill 4. Then, the intermediate rolling is performed in the intermediate universal rolling mill 5. At the time of this intermediate rolling, rolling is applied to the end portion of the material to be rolled (flange portion 80 described later) by the edger rolling mill 9 as needed. Normally, the rolls of the sizing mill 3 and the rough rolling mill 4 are engraved with a total of about 4 to 6 hole molds, and through these, reverse rolling of about multiple passes is performed to form an H-shaped rough roll. The material 13 is formed, and the H-shaped rough-shaped material 13 is subjected to rolling of a plurality of passes by using a rolling mill row consisting of two rolling mills of the intermediate universal rolling mill 5-edger rolling mill 9, and the intermediate material 14 is rolled. Is modeled. Then, the intermediate material 14 is finished and rolled into a product shape in the finishing universal rolling mill 8, and the H-shaped steel product 16 is manufactured.

(Outline of hole type configuration)
Next, the hole-shaped configuration and the hole-shaped shape engraved in the sizing mill 3 and the rough rolling mill 4 shown in FIG. 1 will be described below with reference to the drawings. 2 to 6 are schematic explanatory views of a hole type engraved in the sizing mill 3 and the rough rolling mill 4 that perform the rough rolling process. Here, the first hole type to the fourth hole type described here may be all engraved in, for example, the sizing mill 3, and the sizing mill 3 and the rough rolling mill 4 have five types, the first hole type to the fifth hole type. The hole type may be separately engraved. That is, the first hole type to the fourth hole type may be carved in both the sizing mill 3 and the rough rolling mill 4, or may be carved in either rolling mill. In the rough rolling process in the production of ordinary H-section steel, molding with one or more passes is performed in each of these hole molds.

Further, in the present embodiment, the case where the number of hole types to be engraved is five will be described as an example, but the number of hole types does not necessarily have to be five holes, and the number of holes is five or more. It may be. That is, any hole-shaped structure suitable for modeling the H-shaped rough shape member 13 may be used. In addition, in FIGS. 2 to 6, the approximate final path shape of the material A to be rolled at the time of molding in each hole type is shown by a broken line.

FIG. 2 is a schematic explanatory view of the first hole type K1. The first hole type K1 is engraved on the upper hole type roll 20 and the prepared hole type roll 21 which are a pair of horizontal rolls, and the material A to be rolled is formed in the roll gap between the upper hole type roll 20 and the prepared hole type roll 21. Rolled and shaped. Further, on the peripheral surface of the upper hole type roll 20 (that is, the upper surface of the first hole type K1), a protrusion 25 protruding toward the inside of the hole type is formed. Further, a protrusion 26 projecting toward the inside of the hole type is formed on the peripheral surface of the prepared hole type roll 21 (that is, the bottom surface of the first hole type K1). These protrusions 25 and 26 have a tapered shape, and the protrusion length and other dimensions are the same for the protrusion 25 and the protrusion 26, respectively. The height (projection length) of the protrusions 25 and 26 is h1, and the tip angle is θ1a.

In the first hole type K1, the protrusions 25 and 26 are pressed against the upper and lower end portions (slab end faces) of the material A to be rolled, and interrupts 28 and 29 are formed. Here, it is desirable that the tip angle (also referred to as a wedge angle) θ1a of the protrusions 25 and 26 is, for example, 25 ° or more and 40 ° or less.

Here, it is preferable that the hole shape width of the first hole type K1 is substantially equal to the thickness of the material A to be rolled (that is, the slab thickness). Specifically, by making the width of the hole type at the tips of the protrusions 25 and 26 formed in the first hole type K1 the same as the slab thickness, the left-right centering property of the material A to be rolled is suitably ensured. Will be done. Further, by adopting such a hole-shaped size configuration, as shown in FIG. 2, the protrusions are formed on the upper and lower end portions (slab end faces) of the material A to be rolled during molding with the first hole-shaped K1. The first hole is provided with respect to the upper and lower end portions of the slab which are in contact with the material A to be rolled and are divided into four elements (parts) by interrupts 28 and 29. It is preferable that active rolling is not performed on the upper surface and the bottom surface of the mold K1. This is because the rolling reduction by the upper surface and the bottom surface of the hole type causes the material A to be rolled to stretch in the longitudinal direction, which lowers the production efficiency of the flange (flange portion 80 described later). That is, in the first hole type K1, the protrusions 25 and 26 are pressed against the upper and lower ends (slab end faces) of the material A to be rolled, and the protrusions 25 and 26 are pressed down when the interrupts 28 and 29 are formed. The amount (wedge tip rolling down amount) is set to be sufficiently larger than the rolling down amount (slab end face rolling down amount) at the upper and lower ends of the slab, whereby interrupts 28 and 29 are formed.
Since the first hole type K1 is provided with grooves (interrupts 28 and 29) at the upper and lower ends of the slab, it is also referred to as a "grooved hole type".

FIG. 3 is a schematic explanatory view of the second hole type K2. The second hole type K2 is engraved on the upper hole type roll 30 and the lower hole type roll 31, which are a pair of horizontal rolls. A protrusion 35 projecting toward the inside of the hole type is formed on the peripheral surface of the upper hole type roll 30 (that is, the upper surface of the second hole type K2). Further, a protrusion 36 protruding toward the inside of the hole type is formed on the peripheral surface of the prepared hole type roll 31 (that is, the bottom surface of the second hole type K2). These protrusions 35 and 36 have a tapered shape, and the protrusion length and other dimensions are the same for the protrusion 35 and the protrusion 36, respectively. It is desirable that the tip angle of these protrusions 35 and 36 is a wedge angle θ1b of 25 ° or more and 40 ° or less.

The wedge angle θ1a of the first hole type K1 is the wedge angle of the second hole type K2 in the subsequent stage in order to secure the thickness of the tip corresponding to the flange, enhance the inductivity, and ensure the stability of rolling. It is preferable that the angle is the same as θ1b.

The height (projection length) h2 of the protrusions 35 and 36 is higher than the height h1 of the protrusions 25 and 26 of the first hole type K1, and h2> h1. Further, it is preferable that the tip angle of the protrusions 35 and 36 is the same as the tip angle of the protrusions 25 and 26 of the first hole type K1 in terms of rolling dimensional accuracy. In the roll gap between the upper hole type roll 30 and the lower hole type roll 31, the material A to be rolled after passing through the first hole type K1 is further formed.

Here, the height h2 of the protrusions 35 and 36 formed in the second hole type K2 is higher than the height h1 of the protrusions 25 and 26 formed in the first hole type K1, and the material A to be rolled is higher. Similarly, the second hole type K2 has a longer penetration length into the upper and lower end portions (slab end faces). The penetration depth of the protrusions 35 and 36 into the material A to be rolled in the second hole type K2 is the same as the height h2 of the protrusions 35 and 36. That is, the penetration depth h1'of the protrusions 25 and 26 in the first hole type K1 into the rolled material A and the penetration depth of the protrusions 35 and 36 in the second hole type K2 into the rolled material A. h2 has a relationship with h1'<h2.
Further, the angle θf formed by the hole-shaped upper surfaces 30a and 30b and the hole-shaped bottom surfaces 31a and 31b facing the upper and lower ends (slab end faces) of the material A to be rolled and the inclined surfaces of the protrusions 35 and 36 is shown in FIG. All four locations shown are configured at approximately 90 ° (approximately right angles).

As shown in FIG. 3, since the penetration length of the protrusion when pressed against the upper and lower ends (slab end faces) of the material A to be rolled is long, in the second hole type K2, the first hole type K1 The interrupts 28 and 29 formed in the above are shaped so as to be deeper, and the interrupts 38 and 39 are formed. The width of the flange piece at the end of the flange molding process in the rough rolling process is determined based on the dimensions of the interrupts 38 and 39 formed here.
The second hole type K2 is referred to as an "interrupt hole type".

FIG. 4 is a schematic explanatory view of the third hole type K3. The third hole type K3 is engraved on a pair of horizontal rolls, an upper hole type roll 40 and a lower hole type roll 41. On the peripheral surface of the upper hole type roll 40 (that is, the upper surface of the third hole type K3), a protrusion 45 projecting toward the inside of the hole type is formed. Further, a protrusion 46 protruding toward the inside of the hole type is formed on the peripheral surface of the prepared hole type roll 41 (that is, the bottom surface of the third hole type K3). These protrusions 45 and 46 have a tapered shape, and the protrusion length and other dimensions are the same for the protrusion 45 and the protrusion 46, respectively.

The tip angle θ2 of the protrusions 45 and 46 is configured to be wider than the angle θ1b, and the penetration depth h3 of the protrusions 45 and 46 into the material to be rolled is the penetration depth of the protrusions 35 and 36. It is shorter than h2 (that is, h3 <h2). The angle θ2 is preferably 70 ° or more and 110 ° or less, for example.
Further, the angle θf formed by the hole-shaped upper surfaces 40a and 40b and the hole-shaped bottom surfaces 41a and 41b facing the upper and lower ends (slab end faces) of the material A to be rolled and the inclined surfaces of the protrusions 45 and 46 is shown in FIG. All four locations shown are configured at approximately 90 ° (approximately right angles).

As shown in FIG. 4, in the third hole type K3, the material to be rolled after the second hole type K2 is passed is formed in the second hole type K2 at the upper and lower ends (slab end faces) of the material A to be rolled. The interrupts 38 and 39 that have been generated become interrupts 48 and 49 when the protrusions 45 and 46 are pressed against the interrupts 38 and 39. That is, in the final path in the modeling with the third hole type K3, the deepest angle of the interrupts 48 and 49 (hereinafter, also referred to as an interrupt angle) is θ2. In other words, in the second hole type K2, the divided portion (the portion corresponding to the flange portion 80 described later) formed together with the formation of the interrupts 38 and 39 is bent outward.
The modeling with the third hole type K3 shown in FIG. 4 is performed by a plurality of passes.

FIG. 5 is a schematic explanatory view of the fourth hole type K4. The fourth hole type K4 is engraved on a pair of horizontal rolls, an upper hole type roll 50 and a lower hole type roll 51. A protrusion 55 projecting toward the inside of the hole type is formed on the peripheral surface of the upper hole type roll 50 (that is, the upper surface of the fourth hole type K4). Further, a protrusion 56 protruding toward the inside of the hole type is formed on the peripheral surface of the prepared hole type roll 51 (that is, the bottom surface of the fourth hole type K4). These protrusions 55 and 56 have a tapered shape, and the protrusion length and other dimensions are the same for the protrusion 55 and the protrusion 56, respectively.

The tip angle θ3 of the protrusions 55 and 56 is wider than the angle θ2, and the penetration depth h4 of the protrusions 55 and 56 into the material A to be rolled is the penetration depth of the protrusions 45 and 46. It is shorter than h3 (that is, h4 <h3). The upper limit of the angle θ3 is 180 °.
Further, the angle θf formed by the hole-shaped upper surfaces 50a and 50b and the hole-shaped bottom surfaces 51a and 51b facing the upper and lower ends (slab end faces) of the material A to be rolled and the inclined surfaces of the protrusions 55 and 56 is the third. Similar to the hole type K3, all four locations shown in FIG. 5 are configured at about 90 ° (substantially right angles).

In the fourth hole type K4, interrupts 48 and 49 formed in the third hole type K3 at the upper and lower ends (slab end faces) of the material to be rolled A with respect to the material A to be rolled after passing through the third hole type K3. , The protrusions 55 and 56 are pressed against each other to be expanded and become interrupts 58 and 59. That is, in the final path in the modeling with the fourth hole type K4, the deepest angle of the interrupts 58 and 59 (hereinafter, also referred to as an interrupt angle) is θ3. In other words, in the third hole type K3, the divided portion (the portion corresponding to the flange portion 80 described later) formed together with the formation of the interrupts 48 and 49 is further bent outward. The portion of the upper and lower ends of the material A to be rolled formed in this way is a portion corresponding to the flange of the later H-shaped steel product, and is referred to here as the flange portion 80.
The modeling with the fourth hole type K4 shown in FIG. 5 is performed by a plurality of passes.

The third hole type K3 and the fourth hole type K4 are "bent hole type" in which interrupts are spread and the split portions (rear flange portion 80) at the upper and lower ends of the material A to be rolled are bent outward. Is called. The third hole type K3 and the fourth hole type K4 may be referred to as "first bent hole type" and "second bent hole type" in this order.
Further, the above-mentioned hole type (first hole type K1 to fourth hole type K4) that performs rolling in the vertical direction (width direction) with the slab (material A to be rolled) upright is generically referred to as ". It may be called "edging hole type".

FIG. 6 is a schematic explanatory view of the fifth hole type K5. The fifth hole type K5 is composed of a pair of horizontal rolls, an upper hole type roll 85 and a lower hole type roll 86. As shown in FIG. 6, in the 5th hole type K5, the material A to be rolled formed up to the 4th hole type K4 is rotated by 90 ° or 270 °, and up to the 4th hole type K4, the material A to be rolled is rotated. The flange portions 80 located at the upper and lower ends are arranged so as to be on the rolling pitch line. Then, in the fifth hole type K5, the dimensional adjustment of the flange width is performed by reducing the web portion 82, which is a connecting portion connecting the two flange portions 80, and the flange tip portion of the flange portion 80. In this way, a so-called dogbone-shaped H-shaped rough material (H-shaped rough material 13 shown in FIG. 1) is formed. Since the fifth hole type K5 presses down the web portion 82 to reduce the thickness, it is also called a web thickening hole type or a flat shaped hole type. The rolling molding in this flat molding hole mold (fifth hole mold K5) is also called a flat rolling step or a flat rolling molding, and is performed by one or any plurality of passes.

Reverse rolling of a plurality of passes is performed on the H-shaped rough profile 13 thus formed by using a rolling mill row consisting of two rolling mills, an intermediate universal rolling mill 5-edger rolling mill 9, which is a known rolling mill. Is added, and the intermediate material 14 is formed. Then, the intermediate material 14 is finished and rolled into a product shape in the finishing universal rolling mill 8, and an H-shaped steel product 16 is manufactured (see FIG. 1).

As described above, the first-hole type K1 to the fourth-hole type K4 according to the present embodiment are used to interrupt the upper and lower ends (slab end faces) of the material A to be rolled, and each of them is divided into left and right by the interruption. By bending the portion to the left and right to form the flange portion 80, the H-shaped rough shape material 13 can be formed without rolling down the upper and lower end surfaces of the material A (slab) to be rolled in the vertical direction. It can be carried out. That is, it is possible to form the H-shaped rough profile 13 by widening the flange width as compared with the conventional rough rolling method in which the end face of the slab is always pressed, and as a result, the final product having a large flange width ( H-shaped steel) can be manufactured.

On the other hand, as a result of diligent experiments conducted by the present inventors, when the edging rolling of the material A to be rolled is performed in the edging hole type exemplified by the above-mentioned first hole type K1 to the fourth hole type K4, the present invention is concerned. It has been found that various problems appear in the surface properties of the material A to be rolled. That is, the surface of the slab of the material A to be rolled has an uneven shape in which scale is attached to the unevenness already generated in the steelmaking stage, and the edging rolling of the tip of the slab compresses the tip and amplifies the uneven shape. It ends up.
Further, when the divided portion (rear flange portion 80) as shown in the description of the third hole type K3 and the fourth hole type K4 is bent and shaped, the bending process is such that the inner surface of the flange is on the inside. The surface of the inner surface of the flange is compressed and deformed, and the uneven shape of the surface is further amplified.
That is, in the process of performing edging rolling from the slab, the timing at which the surface texture of the inner surface of the flange of the material A to be rolled becomes the worst is when the edging rolling is completed.

In view of such circumstances, the present inventors have selected the material A to be rolled during edging rolling or the material A to be rolled after edging rolling is completed in the rough rolling process related to the production of H-section steel. On the other hand, "wrinkles" for eliminating surface texture defects such as wrinkle shape developed on the inner surface (simply described as the inner surface and inner surface of the flange) of the upper and lower ends of the material A to be rolled (that is, the flange corresponding portion and the rear flange portion 80). It was devised to carry out the "elimination process". In addition, in performing this "wrinkle elimination process", a configuration was also devised in which a hole type for the process (hereinafter, also referred to as a wrinkle elimination hole type) is engraved on a hole type roll. Hereinafter, the “wrinkle eliminating step” and the “wrinkle eliminating hole type” according to the present embodiment will be described with reference to the drawings.

(Wrinkle elimination hole type configuration)
FIG. 7 is a schematic explanatory view showing the configuration of the wrinkle eliminating hole type KS according to the present embodiment. The wrinkle eliminating hole type KS is composed of a pair of horizontal rolls, an upper hole type roll 105 and a lower hole type roll 106. As shown in FIG. 7, the material A to be rolled during edging rolling is rotated by 90 ° or 270 °, and the flange corresponding portion (flange portion 80) located at the upper and lower ends of the material A to be rolled during edging rolling is formed. , It will be arranged so that it comes on the rolling pitch line. Here, the roll shapes of the upper and lower hole type rolls 105 and 106 are arbitrarily designed, but as a feature thereof, the inner surface (flange inner surface 80a) of the flange portion 80 is in contact with and in contact with the roll peripheral surface. ing.
Here, the inner surface of the flange portion 80 (flange inner surface 80a) indicates a portion that becomes the inner surface of the flange when it becomes an H-shaped steel product, and the web portion 82 connection side of the flange portion 80 is the flange inner surface 80a and the web. The side opposite to the connection portion 82 is the flange outer surface 80b. As shown in the figure, the flange inner surface 80a and the flange outer surface 80b that come into contact with the roll peripheral surfaces of the upper and lower hole type rolls 105 and 106 are present at four locations on the upper, lower, left, and right sides in the schematic cross-sectional view.

Further, the angle between the contact surfaces 105a and 106a that abut and contact the flange inner surfaces 80a of the upper and lower hole type rolls 105 and 106 and the rolling pitch line is the angle formed by the wrinkle eliminating hole type KS. It is desirable that the flange portion 80 is designed according to the inclination angle α of the above.

Further, regarding the contact / contact between the inner surface 80a of the flange portion 80 and the upper and lower hole type rolls 105 and 106, the configuration may be such that the entire surface of the inner surface 80a does not necessarily come into contact. For example, on the inner surface 80a of the flange, the portion where surface texture deterioration such as wrinkles occurs more remarkably at the time of bending is in the range near the root portion of the flange portion 80 (the range close to the connection portion with the web portion 82). Since it is known, the roll design should be such that the relevant range is focused on contact. Specifically, as shown in FIG. 7, the tip of the flange portion 80 in the range W from the contact point between the vertical line in the flange thickness direction from the central portion of the flange outer surface 80b and the flange inner surface 80a to the tip of the flange inner surface 80a. It is preferable to define a range W1 excluding only the length equal to the thickness t from the tip, and to design the roll so that the roll and the inner surface 80a are in contact with each other at least in the range W1.
Of the inner surface 80a, the range of the tip (range of length t) does not have to come into contact with the roll, in addition to the range that the compression deformation in the bending step does not reach, the middle of the latter stage. In the rolling process, the flange thickness increases due to bulging deformation due to edging rolling at the tip, and it becomes possible to easily reduce the thickness of the inner surface of the flange in intermediate universal rolling (intermediate rolling process) and finish universal rolling (finish rolling process). This is because the deterioration of the surface texture is corrected. The reason why the tip thickness t of the flange portion 80 and the range t on the inner surface 80a are the same numerical value t is that the range in which bulging is formed when the tip portion is edging rolled is almost always the thickness range or more. Therefore, at least the portion of the tip range t tends to increase in thickness in the subsequent rolling, and improvement in surface texture can be expected by reducing the thickness in the rolling step in the subsequent stage.

(Wrinkle elimination process)
By providing the wrinkle-removing hole type KS described with reference to FIG. 7 and incorporating the wrinkle-removing process using the hole type at an appropriate timing in the rough rolling process, the surface texture such as the wrinkle shape developed on the inner surface of the flange 80a is poor. Can be resolved. The present inventors used the wrinkle-eliminating hole-type KS at any timing in the rough rolling step performed by the hole-type configuration according to the embodiment of the present invention described above with reference to FIGS. 2 to 6. We examined whether it is preferable to perform the wrinkle elimination process, and found the appropriate timing.

As described above, in the step of performing edging rolling from the slab, the timing at which the surface texture of the inner surface of the flange of the material A to be rolled becomes the worst is when the edging rolling is completed. That is, in the rough rolling step using the first hole type K1 to the fifth hole type K5 described in the present embodiment, in the sense of suppressing the occurrence of wrinkles as much as possible, after the completion of the rolling molding with the fourth hole type K4. It is considered preferable to perform the wrinkle elimination step (that is, after the completion of edging rolling). In this case, the roll shape of the wrinkle eliminating hole type KS is determined based on the tip angle θ3 of the protrusions 55 and 56 of the fourth hole type K4. Further, when the wrinkle eliminating step is performed at this timing, the flange portion 80 is not bent as much as possible from the viewpoint of suppressing deterioration of the surface texture of the material A to be rolled after passing through the wrinkle eliminating hole type KS. It is desirable that the angle θ3 is 180 °, which is the upper limit.

On the other hand, when the wrinkle eliminating step is performed after the rolling molding with the 4th hole type K4 is completed (after the edging rolling is completed), it is effective in suppressing the occurrence of wrinkles, but the flange portion 80 inclination angle α is extremely small. It becomes an angle. For example, when θ3 is 180 °, α is a value close to 0 °. In that case, since the roll comes into contact with the flange inner surface 80a at no angle, there is also a problem that a scratch is likely to occur. Further, in the case of directing the molding such that the flange portion 80 is laid down (increasing the inclination angle α) in the wrinkle eliminating step, the shape of the flange portion 80 may be deformed.
From such a situation, from the viewpoint of suppressing the occurrence of wrinkles and preventing the occurrence of hanging scratches, rough rolling using the first hole type K1 to the fifth hole type K5 described in the present embodiment. In the process, it is considered preferable to perform the wrinkle eliminating step after the rolling molding with the third hole type K3 is completed (that is, during the edging rolling). In this case, the roll shape of the wrinkle eliminating hole type KS is determined based on the tip angle θ2 of the protrusions 45 and 46 of the third hole type K3.

(Relationship with flat rolling modeling)
As described above, after the wrinkle elimination step is performed, that is, after the surface texture of the inner surface 80a of the flange portion 80 is improved, it is preferable to avoid rolling molding in which the surface texture is deteriorated as much as possible. It is preferable to keep the rolled material A as close to the shape of the H-shaped steel product as possible. From this point of view, the structure of the flat shaped hole type (fifth hole type K5 in the present embodiment) to which the material A to be rolled after the wrinkle elimination step is sent is the upper and lower hole type of the flat shaped hole type at the time of rolling molding. It is preferable that the rolls 85 and 86 are not in contact with the inner surface 80a of the flange portion 80. This makes it possible to prevent the surface texture of the flange inner surface 80a from deteriorating again after the wrinkle eliminating step.

As described above, in the rolling molding technique using the first hole type K1 to the fifth hole type K5 according to the present embodiment, the suitable timing for performing the wrinkle eliminating step is the completion of rolling molding with the third hole type K3. Later, or after the completion of rolling molding with the fourth hole mold K4. By performing the wrinkle elimination step at such a timing, it is good to suppress the surface texture defect of the H-shaped rough profile 13 after the rough rolling process, and to suppress the shape defect and the occurrence of scratches in the subsequent process. It is possible to efficiently manufacture H-shaped steel products with various surface textures.

Although an example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the ideas described in the claims, and these also naturally belong to the technical scope of the present invention. It is understood that it is a thing.

In the above embodiment, the material A to be rolled is rolled and molded using the hole mold group shown and described as the first hole type K1 to the fourth hole type K4, and then flat molding is performed using the fifth hole type K5. Although the technique for performing rolling has been described, the number of hole molds for carrying out the rough rolling process is not limited to this, and more hole molds may be used for carrying out the rough rolling process. In that case, it is preferable that the rolling by the wrinkle eliminating hole type KS is performed before the final bent hole type (for example, the fourth hole type K4 in the above embodiment). That is, the hole type configuration shown in the above embodiment is an example, and the number of hole types engraved in the sizing mill 3 and the rough rolling mill 4 can be arbitrarily changed, and the rough rolling step is preferably carried out. It will be changed as appropriate to the extent that it can be done.

(Improvement of hole type efficiency)
The first hole type K1 to the fifth hole type K5 and the wrinkle eliminating hole type KS described in the above embodiment are required to be engraved so as to fit in the hole type roll having a predetermined body length. Further, as described above, it is preferable that the wrinkle eliminating hole type KS is configured to abut and contact only the inner surface 80a of the flange portion 80. In such a case, it is also possible to engrave a hole type for edging rolling (first hole type K1 to fourth hole type K4 in the above embodiment) inside the wrinkle eliminating hole type KS, mainly in the central part. Is.

FIG. 8 is a schematic view showing a modified example of the wrinkle eliminating hole type, and shows a configuration in which an edging hole type is engraved inside the hole type. In order to eliminate wrinkles, at least the inner surface of the flange should be brought into contact with the roll to smooth it, and it is not essential to reduce the pressure of the web part. There is. The edging hole type to be carved inside is arbitrary, and FIG. 8 shows a case where the second hole type K2 is carved as an example. Further, the number of hole types to be engraved inside is arbitrary, and may be appropriately engraved according to the dimensions of the hole type for eliminating wrinkles.
By adopting a configuration in which an edging hole mold is carved inside the wrinkle eliminating hole mold in this way, the number of hole molds that can be carved within a predetermined roll body length can be increased, and a sizing mill or a rough rolling mill can be used. It is possible to improve the equipment efficiency in rolling equipment with such equipment limitations.

In the above embodiment, the slab has been exemplified as the material for producing the H-shaped steel, but the technique of the present invention can be naturally applied to other materials having similar shapes. For example, it can be applied to the conventional edging rolling method, and even in that case, the surface texture can be improved by rolling with the wrinkle eliminating hole mold in the middle of each edging hole mold.

FIG. 9 is a schematic explanatory view showing an example of a conventional edging rolling method. Whereas the conventional edging rolling method is (a) → (b) → (c) → (d) → (e) in FIG. 9, when the wrinkle eliminating hole type KS according to the present invention is applied, , (A) → (b) → (c) → Wrinkle elimination hole type KS → (d) → (e), or (a) → (b) → (c) → (d) → Wrinkle elimination A case such as hole type KS → (e) can be considered.

The present invention can be applied to a manufacturing method for manufacturing H-shaped steel using, for example, a slab having a rectangular cross section as a material.

1 ... Rolling equipment 2 ... Heating furnace 3 ... Sizing mill 4 ... Rough rolling mill 5 ... Intermediate universal rolling mill 8 ... Finishing universal rolling mill 9 ... Edger rolling mill 11 ... Slab 13 ... H-shaped rough profile 14 ... Intermediate material 16 ... H-shaped steel product 20 ... Top hole type roll (first hole type)
21 ... Prepared hole type roll (first hole type)
25, 26 ... Protrusion (first hole type)
28, 29 ... Interrupt (1st hole type)
30 ... Top hole type roll (second hole type)
31 ... Prepared hole type roll (second hole type)
35, 36 ... Protrusion (second hole type)
38, 39 ... Interrupt (second hole type)
40 ... Top hole type roll (third hole type)
41 ... Prepared hole type roll (third hole type)
45, 46 ... Protrusion (third hole type)
48, 49 ... Interrupt (3rd hole type)
50 ... Top hole type roll (4th hole type)
51 ... Prepared hole type roll (4th hole type)
55, 56 ... Protrusion (4th hole type)
58, 59 ... Interrupt (4th hole type)
80 ... Flange part 82 ... Web part 85 ... Top hole type roll (fifth hole type)
86 ... Prepared hole type roll (fifth hole type)
105 ... Top hole type roll (hole type for eliminating wrinkles)
106 ... Prepared hole type roll (hole type for eliminating wrinkles)
K1 ... 1st hole type K2 ... 2nd hole type K3 ... 3rd hole type K4 ... 4th hole type K5 ... 5th hole type (flat molding hole type)
KS ... Hole type for eliminating wrinkles T ... Production line A ... Material to be rolled

Claims (7)

It is a manufacturing method of H-shaped steel including a rough rolling process, an intermediate rolling process, and a finish rolling process.
In the rolling mill that performs the rough rolling process, a plurality of hole molds for rolling and shaping the material to be rolled are engraved.
The plurality of hole types are
Multiple edging hole molds that roll the material to be rolled in the width direction,
For the material to be rolled during edging rolling by the plurality of edging hole molds or after the completion of edging rolling, only a part or all of the inner surface of the flange of the material to be rolled is brought into contact with the hole type roll to perform a wrinkle elimination step. A method for producing an H-shaped steel, which comprises a hole type for elimination. In the wrinkle eliminating hole type, the length of the range W from the contact point between the vertical line in the flange thickness direction from the center of the flange outer surface to the flange inner surface to the tip of the flange inner surface is the same as the tip thickness of the flange portion. The method for producing an H-shaped steel according to claim 1, wherein the wrinkle eliminating step is performed by contacting at least the range W1 excluding only the tip from the tip. The plurality of hole types are
A grooving hole type that vertically groovs the end of the material to be rolled in the width direction,
One or more interrupt hole types in which protrusions are formed to form a split portion at the end of the material to be rolled by vertically interrupting the grooved end in the width direction of the material to be rolled.
A plurality of bent hole types having protrusions formed which are in contact with the interrupt and sequentially bend the divided portions formed in the interrupt hole type are included.
The H-section steel according to claim 1 or 2, wherein the wrinkle eliminating step is performed on the material to be rolled during the bending molding in the plurality of bending hole molds or after the bending molding is completed. Manufacturing method. The plurality of bent hole molds are composed of a first bent hole mold and a second bent hole mold, which are sequentially bent and shaped with respect to the material to be rolled.
The third aspect of the present invention, wherein the wrinkle eliminating step is performed on the material to be rolled after the bending molding in the first folding hole mold or after the bending molding in the second folding hole mold. H-shaped steel manufacturing method. The method for manufacturing an H-shaped steel according to claim 4, wherein the angle of the tip of the protrusion formed in the second bent hole shape is 180 °. The plurality of hole types include the interrupt hole type, the bent hole type, and the flat-shaped hole type that flat-rolls the material to be rolled that has passed through the wrinkle-eliminating hole type. The method for producing an H-shaped steel according to any one of claims 3 to 5, wherein the inner surface of the flange of the material to be rolled and the hole-shaped roll are configured so as not to come into contact with each other. The H-shape according to any one of claims 1 to 6, wherein the plurality of edging hole types are engraved in at least one hole type inside the hole type for eliminating wrinkles. Steel manufacturing method.

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