WO2017188179A1 - H-shaped steel manufacturing method - Google Patents

Abstract

[Problem] To efficiently and stably manufacture an H-shaped steel product, such that the occurrence of shape defects in a material to be rolled can be suppressed, the growth of a crop part can be reduced, and the flange width can be increased compared to the prior art by forming a deep interruption in a projecting part having an acute-angled distal end shape in an end surface of a material such as a slab, and then successively bending a flange part formed thereby. [Solution] In a first groove and a second groove among a plurality of grooves, an interruption is formed vertically relative to the width direction of a material to be rolled to form a protruding part that forms a divided region at the end of the material to be rolled. In the third groove and beyond excluding the final groove among the plurality of grooves, a protruding part is formed that abuts the interruption and that successively bends the formed divided region. Rolling and shaping is carried out upon expanding a rolling roller gap relative to a predetermined section of a rear end in the rolling longitudinal direction of the material to be rolled compared to a rolling roller gap relative to portions other than the predetermined section, with at least one rolling/shaping pass in the plurality of grooves.

Description

Manufacturing method of H-section steel

(Cross-reference of related applications)
This application claims priority based on Japanese Patent Application No. 2016-090165 for which it applied to Japan on April 28, 2016, and uses the content here.

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

When manufacturing H-section steel, raw materials such as slabs and blooms extracted from a heating furnace are formed into a rough shape material (a so-called dogbone-shaped material to be rolled) by a rough rolling mill, and the above-mentioned by an intermediate universal rolling mill. The web of the rough material and the thickness of the flange are reduced, and the flange of the material to be rolled is subjected to width reduction and forging and shaping of the flange of the material to be rolled by an edger rolling mill close to the intermediate universal rolling mill. And an H-section steel product is modeled by a finishing universal rolling mill.

In such a method for manufacturing an H-shaped steel, when forming a so-called dogbone-shaped rough shape material from a slab material having a rectangular cross section, an interruption was applied to the slab end face in the first hole mold of the rough rolling process. Thereafter, a technique is known in which the interruption is extended in the second and subsequent hole molds, or the interruption depth is increased to perform edging rolling, and the interruption of the slab end face is erased in the subsequent hole molds (for example, Patent Document 1).

JP-A-7-88501

In recent years, with the increase in size of structures and the like, the manufacture of large H-section steel products is desired. In particular, a product having a wider flange than the conventional one that greatly contributes to the strength and rigidity of the H-shaped steel is desired. In order to manufacture an H-shaped steel product having a wide flange, it is necessary to form a material to be rolled having a larger flange width than that of the prior art from modeling in the rough rolling process.

However, for example, in the technique disclosed in Patent Document 1 described above, in the method of interrupting the end face (slab end face) of a material such as a slab, edging the end face, and performing rough rolling using its widening, There is a limit to widening the flange. That is, in order to increase the width of the flange in the conventional rough rolling method, the width can be improved by techniques such as wedge design (interrupt angle design), reduction adjustment, and lubrication adjustment. Since it does not contribute significantly, the width expansion ratio indicating the ratio of the flange width expansion amount to the edging amount is about 0.8 even under the highest efficiency in the initial stage of edging. Under repeated conditions, it is known that the flange width decreases as the amount of expansion increases, and finally becomes about 0.5. In addition, it is conceivable to increase the edging amount of the material itself such as the slab, but there is an equipment limit on the equipment size, reduction amount, etc. of the roughing mill, so that it is not possible to realize a sufficiently wide product flange. There are circumstances.

Further, it is generally known that, in the manufacture of H-section steel, an unnecessary portion called a crop portion is formed at the front and rear end portions in the longitudinal direction of the material to be rolled. For such a crop portion, intermediate crop cutting is performed in the middle of a series of rolling processes, and the trouble that the crop portion is clogged in the rolling mill is avoided.
In particular, in the manufacture of large H-shaped steel products, the weight per unit length of the material to be rolled is large and the product elongation during rolling is short, so the proportion of the crop portion in the total length is large, and the crop portion Growth tends to lead to a decrease in yield. Therefore, the fact is that it is required to reduce the growth of the crop portion as much as possible particularly in the production of large H-shaped steel products.

In view of the above circumstances, the purpose of the present invention is to deeply interrupt the protrusions having an acute tip shape on the end face of the material such as the slab in the rough rolling process using the hole mold when manufacturing the H-section steel, By successively bending the flange portion formed thereby, the occurrence of shape defects in the material to be rolled is suppressed, and the growth of the crop portion, which has been a significant yield loss in the manufacture of large H-section steels in the past, has been reduced. An object of the present invention is to provide an H-section steel manufacturing technique capable of efficiently and stably manufacturing an H-section steel product having a larger flange width than conventional ones.

In order to achieve the above object, according to the present invention, there is provided a method for producing an H-section steel comprising a rough rolling process, an intermediate rolling process, and a finish rolling process, wherein a rolling mill that performs the rough rolling process includes: Five or more hole molds for rolling and shaping the rolled material are engraved, and one or more passes of the material to be rolled are formed in the plurality of hole molds. Among the plurality of hole molds, the first hole mold and the first hole mold are formed. In the two-hole mold, a protrusion is formed that interrupts perpendicularly to the width direction of the material to be rolled to form a divided portion at the end of the material to be rolled. After the three-hole type, a protrusion that abuts against the interruption and sequentially folds the formed divided portions is formed, and the final hole type among the plurality of hole types is a flat modeling hole type, and the plurality of hole types Of the material to be rolled in the formation of at least one pass after the second hole mold except the final hole mold. The rolling is performed in a state where the surface and the peripheral surface of the hole mold are in contact with each other, and the rolling roll gap with respect to a predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled is at least one pass of rolling shaping in the plurality of hole molds A method for producing an H-section steel is provided, in which rolling shaping is performed by expanding the shape of the steel sheet in comparison with the rolling roll gaps other than the predetermined section.

The tip angle of the protrusions formed in the first hole mold and the second hole mold may be 25 ° or more and 40 ° or less.

In all passes of rolling shaping with the first hole mold among the plurality of hole molds, the rolling roll gap for the predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled is wider than the rolling roll gap for other than the predetermined section. Roll forming may be performed.

Among all of the plurality of hole molds, at least in all passes of the rolling modeling in the third hole mold and the fourth hole mold, the rolling roll gap with respect to a predetermined section at the rear end portion in the rolling longitudinal direction of the material to be rolled is other than the predetermined section. Rolling shaping may be performed in a manner wider than the rolling roll gap.

In rolling modeling with the second hole mold among the plurality of hole molds, in a pass where the rolling is performed in a state where the end face of the material to be rolled and the hole mold peripheral surface of the second hole mold are in contact with each other, Rolling shaping may be performed by expanding the rolling roll gap for a predetermined section at the rear end in the rolling longitudinal direction as compared with the rolling roll gap for other than the predetermined section.

In all passes of rolling shaping in the final hole mold among the plurality of hole molds, the rolling roll gap for the predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled is expanded as compared with the rolling roll gap for other than the predetermined section. Roll forming may be performed.

In all passes of rolling shaping in all the hole types except the first hole type and the final hole type among the plurality of hole types, the rolling roll gap with respect to a predetermined section of the rolling longitudinal rear end portion of the material to be rolled is Rolling shaping may be performed by expanding the rolling roll gap other than the predetermined section.

The intermediate crop cutting step may be performed only on the web portion of the material to be rolled after the rough rolling step and before the intermediate rolling step.

After completion of all of the rough rolling step, intermediate rolling step, and finish rolling step, the crop-shaped portion formed at the end in the longitudinal direction of the material to be rolled may be removed for the first time.

The rolling mill that performs the rough rolling process may be provided with a reduction mechanism that changes the roll gap of the perforated roll of the rolling mill.

According to another aspect of the present invention, an H-section steel product manufactured by the above H-section steel manufacturing method, wherein the web height is 1000 mm or more or the flange width is 400 mm or more. H-shaped steel products are provided.

According to the present invention, in the rough rolling process using the hole mold when manufacturing the H-section steel, the end face of the material such as the slab is deeply interrupted by the protrusion portion having an acute tip shape, and thereby formed. By bending the flange part sequentially, the occurrence of shape defects in the material to be rolled is suppressed, and the growth of the crop part, which has been a large yield loss in the production of large H-section steels in the past, has been reduced. It becomes possible to efficiently and stably manufacture a wide H-shaped steel product.

It is a schematic explanatory drawing about the production line of H-section steel. It is a schematic explanatory drawing of a 1st hole type | mold. It is a schematic explanatory drawing of a 2nd hole type | mold. It is a schematic explanatory drawing of a 3rd hole type | mold. It is a schematic explanatory drawing of a 4th hole type | mold. It is a schematic explanatory drawing of a 5th hole type | mold (flat modeling hole type | mold). It is a schematic explanatory drawing regarding the conventional H-section steel rolling technique. In the manufacturing method of the H-section steel which concerns on this Embodiment, it is a schematic explanatory drawing at the time of applying a double piece pass rolling by the rolling shaping | molding with a 2nd hole type. In the manufacturing method of the H-section steel which concerns on this Embodiment, it is a schematic explanatory drawing at the time of applying a double piece pass rolling by the rolling shaping | molding with a 5th hole type | mold. It is a graph which shows the verification result of the reference example 1 and the reference example 2. FIG. It is explanatory drawing which compares the shape of the flange part after edging rolling in the conventional manufacturing method, and the shape of the flange part shape | molded by the 1st hole type | mold-4th hole type | mold which concerns on this Embodiment. It is a graph which shows the measurement result of a comparative example. It is a graph which shows the measurement result of an Example.

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

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

FIG. 1 is an explanatory diagram of an H-section steel production line T including a rolling facility 1 according to the present embodiment. As shown in FIG. 1, a heating furnace 2, a sizing mill 3, a roughing 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 description, the steel materials in the production line T will be collectively referred to as “rolled material A” for the sake of explanation, and the shape may be appropriately illustrated using broken lines, diagonal lines, etc. in each drawing.

As shown in FIG. 1, in the production line T, a rectangular cross-section material (later rolled material A), for example, a slab 11 extracted from the heating furnace 2 is roughly rolled in a sizing mill 3 and a roughing mill 4. Next, intermediate rolling is performed in the intermediate universal rolling mill 5. At the time of this intermediate rolling, the edger rolling machine 9 reduces the flange tip portion (flange corresponding portion 12) of the material to be rolled as necessary. In the normal case, the rolls of the sizing mill 3 and the roughing mill 4 are engraved with so-called flat shaping hole molds for reducing the thickness of the edging hole mold and the web part and forming the shape of the flange part. Then, the H-shaped rough profile 13 is formed by reverse rolling of a plurality of passes, and the H-shaped rough profile 13 is formed by using a rolling mill row composed of two rolling mills, the intermediate universal rolling mill 5-edger rolling mill 9. A plurality of passes of reduction are applied, and the intermediate material 14 is formed. Then, the intermediate material 14 is finish-rolled into a product shape in the finish universal rolling mill 8 to produce an H-section steel product 16.

Here, the slab thickness T of the slab 11 extracted from the heating furnace 2 is in the range of 240 mm or more and 310 mm or less, for example. This is a slab size used when manufacturing a general H-shaped steel product.

Next, a description will be given of the hole configuration and the hole shape engraved in the sizing mill 3 and the roughing mill 4 shown in FIG. 1 with reference to the drawings. 2 to 6 are schematic explanatory views of the sizing mill 3 for performing the rough rolling process and the hole mold formed in the rough rolling mill 4. FIG. Here, the first to fourth hole molds to be described may be all engraved in, for example, the sizing mill 3, and the sizing mill 3 and the roughing mill 4 have five holes of the first to fifth hole molds. The hole mold may be engraved separately. That is, the first hole type to the fourth hole type may be engraved over both the sizing mill 3 and the rough rolling mill 4, or may be engraved in either one of the rolling mills. In the rough rolling process in the manufacture of normal H-section steel, modeling is performed in one or a plurality of passes in each of these perforations.

Further, in the present embodiment, a case where there are five hole types to be engraved will be described as an example. However, the number of hole types is not necessarily a five-hole type, and a plurality of five or more hole types may be used. It may be. In other words, any hole configuration suitable for modeling the H-shaped rough member 13 may be used. 2 to 6, the approximate final path shape of the material A to be rolled at the time of shaping in each hole mold is illustrated by a broken line.

FIG. 2 is a schematic explanatory diagram of the first hole mold K1. The first hole mold K1 is engraved in the upper hole roll 20 and the lower hole roll 21 which are a pair of horizontal rolls, and the material A to be rolled is placed in the roll gap between the upper hole roll 20 and the lower hole roll 21. Reduced 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 protruding portion 25 that protrudes toward the inside of the hole type is formed. Further, a projection 26 is formed on the peripheral surface of the lower hole roll 21 (that is, the bottom surface of the first hole mold K1) protruding toward the inside of the hole mold. These projecting portions 25 and 26 have a tapered shape, and the projecting length and other dimensions are equal between the projecting portion 25 and the projecting portion 26. The height (projection length) of the protrusions 25 and 26 is h1, and the tip angle is θ1a.

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

Here, it is preferable that the hole width of the first hole mold K1 is substantially equal to the thickness of the material A to be rolled (that is, the slab thickness). Specifically, by making the hole mold width and the slab thickness the same at the tips of the protrusions 25 and 26 formed in the first hole mold K1, the right and left centering property of the material to be rolled A is suitably secured. Is done. Moreover, by setting it as such a hole-type dimension, as shown in FIG. 2, at the time of modeling with the 1st hole type K1, in the upper-lower-end part (slab end surface) of the to-be-rolled material A, the said protrusion The first holes are formed on the upper and lower ends of the slabs, which are partly in contact with the material A to be rolled, and divided into four elements (parts) by interruptions 28 and 29. It is preferable that no positive reduction is performed on the top and bottom surfaces of the mold K1. This is because the reduction by the top and bottom surfaces of the hole mold causes the material A to be elongated in the longitudinal direction, thereby reducing the generation 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 surfaces) of the material A to be rolled, and the reduction in the protrusions 25 and 26 when the interrupts 28 and 29 are formed. The amount (wedge tip reduction amount) is sufficiently larger than the reduction amount (slab end surface reduction amount) at the upper and lower ends of the slab, whereby interrupts 28 and 29 are formed.

FIG. 3 is a schematic explanatory diagram of the second hole type K2. The 2nd hole type | mold K2 is engraved by the upper hole type | mold roll 30 and the lower hole type | mold roll 31 which are a pair of horizontal rolls. On the peripheral surface of the upper hole type roll 30 (that is, the upper surface of the second hole type K2), a protruding portion 35 that protrudes toward the inside of the hole type is formed. Further, a projection 36 that protrudes toward the inside of the hole mold is formed on the peripheral surface of the lower hole roll 31 (that is, the bottom surface of the second hole mold K2). These projecting portions 35 and 36 have a tapered shape, and the projecting length and other dimensions are configured to be equal between the projecting portion 35 and the projecting portion 36. It is desirable that the tip end angle of the projections 35 and 36 is a wedge angle θ1b of 25 ° or more and 40 ° or less.

The wedge angle θ1a of the first hole mold K1 is a wedge angle of the second hole mold K2 in the subsequent stage in order to secure the tip end thickness of the flange-corresponding portion, increase the inductivity, and ensure the stability of rolling. The angle is preferably the same as θ1b.

The height (projection length) h2 of the protrusions 35 and 36 is configured to be higher than the height h1 of the protrusions 25 and 26 of the first hole type K1, and h2> h1. In addition, it is preferable in terms of rolling dimension accuracy that the tip end angles of the projections 35 and 36 are the same as the tip end angles of the projections 25 and 26 of the first hole mold K1. In the roll gap between the upper hole roll 30 and the lower hole roll 31, the material A to be rolled after the first hole K1 passing material is further shaped.

Here, the height h2 of the protrusions 35 and 36 formed on the second hole mold K2 is higher than the height h1 of the protrusions 25 and 26 formed on the first hole mold K1, and the material A to be rolled A Similarly, the length of penetration into the upper and lower ends (slab end face) of the second hole mold K2 is longer. The penetration depth of the projections 35 and 36 into the material to be rolled A in the second hole mold K2 is the same as the height h2 of the projections 35 and 36. That is, the penetration depth h1 ′ of the protrusions 25 and 26 into the rolled material A in the first hole mold K1, and the penetration depth of the protrusions 35 and 36 into the rolled material A in the second hole mold K2. h2 has a relationship of h1 ′ <h2.
Further, an angle θf formed by the hole top surfaces 30a and 30b and the hole bottom surfaces 31a and 31b facing the upper and lower ends (slab end surfaces) of the material A to be rolled and the inclined surfaces of the protrusions 35 and 36 is shown in FIG. The four locations shown are each configured at about 90 ° (substantially at right angles).

As shown in FIG. 3, since the intrusion length of the protrusion when pressed against the upper and lower ends (slab end face) of the material A is long, in the second hole type K2, the first hole type K1. Modeling is performed so that the interrupts 28 and 29 formed in step 1 are further deepened, and interrupts 38 and 39 are formed. The flange piece width at the end of the flange shaping process in the rough rolling process is determined based on the dimensions of the interrupts 38 and 39 formed here.

In addition, the second hole mold K2 is formed by multiple passes, but in the multipass formation, the upper and lower ends (slab end surfaces) of the material A to be rolled and the hole upper surface 30a facing it in the final pass. , 30b and the hole bottom surfaces 31a and 31b are shaped. This is because if the upper and lower ends of the material to be rolled A and the inside of the hole mold are not in contact with each other in the second hole mold K2, the flange equivalent part (the part corresponding to the flange part 80 described later) is asymmetrical. This is because there is a possibility that a shape defect such as being formed will occur, and there is a problem in terms of material permeability.

FIG. 4 is a schematic explanatory diagram of the third hole type K3. The third hole type K3 is engraved in the upper hole type roll 40 and the lower hole type roll 41 which are a pair of horizontal rolls. 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 that protrudes toward the inside of the hole type is formed. Further, a projection 46 is formed on the peripheral surface of the lower hole roll 41 (that is, the bottom surface of the third hole mold K3) protruding toward the inside of the hole mold. The protrusions 45 and 46 have a tapered shape, and the protrusion 45 and the protrusion 46 have the same dimensions such as the protrusion length.

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

As shown in FIG. 4, in the 3rd hole type | mold K3, it forms in the 2nd hole type | mold K2 in the upper and lower end part (slab end surface) of the to-be-rolled material A with respect to the to-be-rolled material A after 2nd hole type | mold K2 passing material. The interrupts 38 and 39 thus generated become interrupts 48 and 49 when the projections 45 and 46 are pressed against each other. That is, in the final pass in modeling with the third hole mold K3, the deepest part angle of the interrupts 48 and 49 (hereinafter also referred to as the interrupt angle) is θ2. In other words, modeling is performed such that the divided part (part corresponding to the flange portion 80 described later) which is modeled together with the formation of the interrupts 38 and 39 in the second hole type K2 is bent outward.

In addition, the shaping with the third hole mold K3 shown in FIG. 4 is performed by at least one pass, and at least one of these passes is the upper and lower ends (slab end surface) of the material A to be rolled and the inside of the hole mold (second This is performed in a state in which the top surface and the bottom surface of the three-hole mold K3 are in contact with each other. In a state where the upper and lower end portions (slab end surfaces) of the material A to be rolled are in contact with the inside of the hole mold, it is preferable that the end portions are lightly reduced.

FIG. 5 is a schematic explanatory diagram of the fourth hole type K4. The 4th hole type | mold K4 is engraved by the upper hole type | mold roll 50 and the lower hole type | mold roll 51 which are a pair of horizontal rolls. On the peripheral surface of the upper hole roll 50 (that is, the upper surface of the fourth hole mold K4), a protrusion 55 is formed that protrudes toward the inside of the hole mold. Further, a projection 56 that protrudes toward the inside of the hole mold is formed on the peripheral surface of the lower hole roll 51 (that is, the bottom surface of the fourth hole mold K4). These projecting portions 55 and 56 have a tapered shape, and the projecting length and other dimensions are configured to be equal between the projecting portion 55 and the projecting portion 56.

The tip end angle θ3 of the projections 55 and 56 is configured to be wider than the angle θ2, and the penetration depth h4 of the projections 55 and 56 into the rolled material A is the penetration depth of the projections 45 and 46. The length is shorter than h3 (that is, h4 <h3).
Further, the angle θf formed by the hole top surfaces 50a and 50b and the hole bottom surfaces 51a and 51b facing the upper and lower ends (slab end surfaces) of the material A to be rolled and the inclined surfaces of the protrusions 55 and 56 is the third angle. As with the hole type K3, the four locations shown in FIG. 5 are each configured at about 90 ° (substantially perpendicular).

In the fourth hole mold K4, the interruptions 48 and 49 formed in the third hole mold K3 at the upper and lower end portions (slab end surfaces) of the material A to be rolled with respect to the material A to be rolled after passing the third hole mold K3. When the projections 55 and 56 are pressed against each other, they are expanded and interrupts 58 and 59 are generated. That is, in the final pass in modeling with the fourth hole mold K4, the deepest part angle of the interrupts 58 and 59 (hereinafter also referred to as the interrupt angle) is θ3. In other words, modeling is performed such that the divided part (part corresponding to the flange portion 80 described later) which is modeled with the formation of the interrupts 48 and 49 in the third hole mold K3 is further bent outward. The portions of the upper and lower end portions of the material A to be rolled thus formed are portions corresponding to the flanges of the subsequent H-shaped steel product, and are referred to as flange portions 80 here.

The modeling with the fourth hole mold K4 shown in FIG. 5 is performed by at least one pass, and at least one of these passes is the upper and lower ends (slab end face) of the material A to be rolled and the inside of the hole mold (fourth hole). This is performed in a state where the upper surface and the bottom surface of the mold K4 are in contact with each other. In a state where the upper and lower end portions (slab end surfaces) of the material A to be rolled are in contact with the inside of the hole mold, it is preferable that the end portions are lightly reduced.

FIG. 6 is a schematic explanatory view of the fifth hole type K5. The fifth hole type K5 includes an upper hole type roll 85 and a lower hole type roll 86 which are a pair of horizontal rolls. As shown in FIG. 6, in the fifth hole mold K5, the material A to be rolled formed up to the fourth hole mold K4 is rotated by 90 ° or 270 °, and until the fourth hole mold K4, the material A of the material to be rolled A is rotated. The flange portions 80 located at the upper and lower ends are arranged so as to be on the rolling pitch line. And in the 5th hole type K5, the dimension adjustment of the flange width is performed by reducing the web part 82 which is a connection part which connects the two flange parts 80, and the flange front-end | tip part of the flange part 80. In this way, a so-called dogbone-shaped H-shaped rough shape (H-shaped rough shape 13 shown in FIG. 1) is formed. In addition, since this 5th hole type | mold K5 reduces the thickness by pressing down the web part 82, it is also called a web thickness reduction hole type | mold or a flat modeling hole type | mold.

A multi-pass reverse rolling is performed on the H-shaped rough shaped material 13 formed in this way 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 to form the intermediate material 14. And the intermediate material 14 is finish-rolled by the finishing universal rolling mill 8 to a product shape, and the H-section steel product 16 is manufactured (refer FIG. 1).

As described above, the upper and lower ends (slab end surfaces) of the material A to be rolled are interrupted using the first hole mold K1 to the fourth hole mold K4 according to the present embodiment, and the left and right parts are divided by the interrupts. Forming the H-shaped rough shape 13 without substantially rolling down the upper and lower end surfaces of the material A (slab) to be rolled by forming the flange portion 80 by performing a process of bending the portion left and right. It can be carried out. That is, compared with the conventional rough rolling method in which the end face of the slab is always squeezed, the flange width can be widened to form the H-shaped rough shape 13, and as a result, a final product having a large flange width ( H-shaped steel) can be manufactured.

Here, in the manufacturing method of the H-section steel according to the present embodiment, the shape of the flange portion 80 of the material A to be rolled formed by the first hole mold K1 to the fourth hole mold K4 described above is the conventional manufacturing. Compared to the shape of the flange part before flat hole shaping in the method, the shape is close to the shape of the product flange. This is based on the fact that it adopts a modeling technique that performs the process of bending the segmented part (flange portion 80) that is modeled with interruption without changing the end shape of the material (slab) having a rectangular cross section used as the material. to cause. FIG. 11 is an explanatory diagram comparing the shape of the flange portion after edging rolling in the conventional manufacturing method and the shape of the flange portion 80 formed by the first hole mold K1 to the fourth hole mold K4 described above. . Also from FIG. 11, it can be seen that the shape of the flange portion formed by the method for manufacturing the H-section steel according to the present embodiment is a shape close to the shape of the product flange.
In such modeling technology, rolling modeling proceeds without actively rolling down the upper and lower ends (slab end surfaces) of the material A to be rolled in the first hole mold K1 to the fourth hole mold K4. Thus, the elongation in the longitudinal direction of the material to be rolled A (in particular, the flange portion 80) is extremely small.

On the other hand, in the conventional H-section steel manufacturing technology, the flange portion is actively reduced in the edging rolling stage (corresponding to the rolling shaping in the first hole mold K1 to the fourth hole mold K4 in the present embodiment). The flange portion is stretched more than the web portion with respect to the longitudinal direction of the material A to be rolled, and a cut shape (so-called crop shape) is generated at the longitudinal direction end of the material to be rolled, which is called a fish tail. It was known that. Further, in the flat hole rolling stage (rolling shaping with the fifth hole mold K5 in the present embodiment), the web portion has a reduction ratio larger than that of the flange portion, so that a crop shape called a tongue is generated. It was known to end up. Hereinafter, these crop shapes will be described with reference to FIG.
FIG. 7 is a schematic explanatory diagram regarding the conventional H-shaped steel rolling technology, (a) is a schematic side view of the conventional edging rolling viewed from the side, and (b) is a conventional flat hole rolling from above. FIG. In addition, the left side in FIG. 7 shows the upstream side of rolling.

As shown in FIG. 7 (a), in the conventional H-section steel manufacturing technology, since the flange portion is actively reduced in the edging rolling stage, the elongation of the flange portion in the longitudinal direction of the material A to be rolled is a web. As a result, the crop shape portion 90 called a fish tail is formed (see the broken line portion in FIG. 7A).
Thereafter, as shown in FIG. 7 (b), in the conventional H-section steel manufacturing technology, the rolling reduction of the web portion is relatively larger than that of the flange portion at the flat hole rolling stage, so that the longitudinal direction of the material A to be rolled In FIG. 7, the elongation of the web portion exceeds the elongation of the flange portion, so that a crop-shaped portion 92 called a tongue is formed (see the broken line portion in FIG. 7B).
Such crop-shaped portions 90 and 92 called fish tails or tongues are formed and grown at both the rolling biting end and the rolling kicking end, and it is known that the growth at the rolling kicking end is particularly remarkable. ing.
Note that the length in the longitudinal direction of the crop-shaped portion 90 formed in this way is L1, and the length in the longitudinal direction of the crop-shaped portion 92 is L2.

The crop-shaped portions 90 and 92 formed in this way have a problem that it is difficult to continue the intermediate rolling because there is a risk of causing a failure of biting into the rolling mill in the subsequent process (intermediate rolling process). Specifically, the cropped portions 90 and 92 shown in FIG. 7B cause the following problems.

That is, when a crop-shaped portion 90 called a fish tail is formed, in the intermediate rolling as a subsequent process, the flange portion of the material A to be rolled is rolled between the horizontal roll side surface and the heel roll during universal rolling, And since a roll is normally a non-driving roll, it tends to bend the to-be-rolled material A on the exit side of the universal rolling mill, and tends to be rolled into the chock. In addition, the crop-shaped portion 90 having a shape that precedes the flange portion can be connected to the web-flange by inserting the flange portion as it is and changing the web portion when the vertical shift occurs when biting in the rolling mill. This may lead to serious rolling troubles such as tearing the base portion, and dimensional deterioration.

In addition, the crop-shaped portion 92 having a shape leading to the web is a web-flange connecting portion in order to roll the flange portion at the same position when a left-right shift occurs when biting in the rolling mill. It may lead to serious rolling troubles such as tearing the root and dimensional deterioration.

In view of such problems that lead to various dimensional deterioration, in the conventional H-section steel manufacturing technology, for example, between the rough rolling process and the intermediate rolling process, the crop-shaped part 90 and the crop-shaped part 92 are provided. An intermediate crop cutting step for cutting as a cut-off site is provided and supported.

In view of the circumstances described above with reference to FIG. 7, the present inventors suppress the growth of the crop-shaped portion 90 and the crop-shaped portion 92 formed in the rough rolling process (edging rolling and flat hole rolling). The following findings were obtained.

In the method for manufacturing the H-section steel according to the present embodiment, the description has been given of using the first hole mold K1 to the fifth hole mold K5 for performing rolling shaping in FIGS. 2 to 6, but these hole molds were used. In rolling, a hole roll in which a hole mold is engraved has a configuration in which the roll gap can be freely changed. Further, the roll gap can be changed during the rolling modeling of the material A to be rolled, and the reduction amount can be changed. Such a change in the roll gap is, for example, a rolling mill (sizing) having a reduction mechanism (hydraulic mechanism, not shown in FIGS. 2 to 6) for moving the perforated roll to change the roll gap. It is carried out by using a mill 3 and a rough rolling mill 4).

Based on such a configuration of the rolling mill, the present inventors can perform rolling shaping with one or any plurality of hole shapes when performing rolling shaping using the first hole shape K1 to the fifth hole shape K5. The idea was to create a rolling model by a so-called double-piece rolling process. Double-pass rolling refers to the longitudinal direction of the material A to be rolled in all the passes that reciprocate the material A when a plurality of reverse rolls are performed on the material A to be rolled in one perforation, for example. This is a technique in which the roll gap is expanded only when a section having a predetermined length at the rear end is rolled, and the reduction amount in the hole mold is reduced below the normal reduction amount, or the reduction amount is set to zero. The hole mold for performing the double-piece pass rolling may be any one of the first hole mold K1 to the fifth hole mold K5, or may be a plurality of two or more hole molds.
As described above, in the conventional manufacturing technique, the crop-shaped portions 90 and 92 called fishtails or tongues are formed and grown at both the rolling biting end and the rolling kicking end, particularly at the rolling kicking end. Although the growth is remarkable, the growth of the cropped portions 90 and 92 can be suppressed by applying the above-mentioned double-piece pass rolling to reduce or reduce the reduction amount in a predetermined section.

FIG. 8 is a schematic explanatory view when a double piece pass rolling is applied by rolling shaping with the first hole mold K1 in the method for manufacturing the H-section steel according to the present embodiment, and a schematic side view seen from the side. It is. In addition, in FIG. 8, for the sake of explanation, the material A to be rolled before rolling shaping in a certain pass (left side in the figure), immediately before completion of rolling shaping in the pass (center in the figure), and rolling shaping in the pass After completion (right side in the figure) is shown.

As shown in FIG. 8, in a certain pass in rolling modeling with the first hole mold K1 according to the present embodiment, from the start of rolling modeling to just before the end of rolling modeling, in order to implement the rolling modeling shown in FIG. Rolling modeling is performed with a necessary roll gap (interval between the upper hole roll 20 and the lower hole roll 21). On the other hand, in the rolling modeling for the predetermined section L from the end of rolling modeling in the pass to the end of rolling modeling, the rolling modeling is performed in a state where the roll gap is widened (see the broken line portion in FIG. 8). Specifically, the roll gap may be expanded stepwise so as to gradually reduce the amount of reduction immediately before the end of rolling shaping, or the roll gap may be greatly expanded so that the reduction amount is zero.

In the rolling shaping performed in this way, the rolling shaping is performed on the material A to be rolled in a state where the amount of reduction is small (or no amount of reduction) for the predetermined section L compared to other sections. Not so much reduction in the longitudinal direction of the rolled material A is performed. Accordingly, in the edging rolling stage described above with reference to FIG. 7A, the elongation of the flange portion exceeds the elongation of the web portion, and a so-called fish tail is hardly formed. That is, since the reduction amount in the predetermined section L is reduced or becomes zero at the rolling kick end, the growth of the cropped portion 90 as described above is suppressed. For this reason, it becomes possible to omit or simplify the intermediate crop cutting step as described above, and to improve the yield and the efficiency of rolling.

In addition, when reverse rolling is adopted in the edging rolling stage, in the next pass of the pass described in FIG. 8, rolling shaping is performed in a direction opposite to the direction shown in FIG. 8, so the predetermined section L is a biting end. Become. At this time, since the roll gap allows a predetermined rolling modeling, the rolling modeling is applied to the predetermined section L as a biting end in this pass. That is, sufficient rolling modeling is performed for the predetermined section L as well.
Here, in FIG. 8, the first hole mold K1 has been described as an example, but the same function and effect can be applied to each hole mold used in the edging rolling stage, and the double piece pass rolling is performed in the edging rolling stage. It is also possible to apply to one or a plurality of hole types used in the above.

In the rough rolling process according to the present embodiment described above with reference to FIGS. 2 to 6, in the edging rolling stage, in particular, the first hole type K1 that forms the first interruption at the slab end face and the formation by interruption. Crop growth is remarkable in the third hole mold K3 and the fourth hole mold K4 that perform modeling for bending the divided parts. This is because, in the process of first forming an interrupt on the end face of the slab, it is edged in a strongly constrained state by the perforated side wall, and in the process of bending the divided part, the slab width direction is applied during bending deformation. This is because a predetermined amount of reduction is applied to the slab, and the slab end face is finally edged in contact with the perforated peripheral surface. This is also clear from the fact that the crop length grows mainly in G1 and G3 in G1 to G3 corresponding to edging rolling in the first hole mold K1 to the third hole mold K3 in the examples described later. (See FIG. 10).

That is, an edging-rolling shaped hole mold after the first hole mold K1 and / or the third hole mold K3 (the third hole mold in the present embodiment), which may form a defective portion called a so-called fishtail. For K3 and the fourth hole type K4), it is particularly preferable to apply double-piece pass rolling.
In addition, since the growth of a defective shape part (crop part) is small, the double piece pass rolling is necessarily applied to the second hole type K2 which is shaped to further deepen the interruption formed in the first hole type K1. You don't have to.

However, also in the second hole mold K2, the growth of the cropped portion is larger in the pass that is squeezed while the end face of the material to be rolled is in contact with the peripheral face of the hole mold than in the other passes. Accordingly, even in the rolling shaping with the second hole mold K2, in a pass that is squeezed while the end face of the material to be rolled and the peripheral face of the hole mold are in contact with each other, a predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled It is preferable that the rolling roll gap with respect to is expanded compared with the rolling roll gap with respect to other than the predetermined section, and the rolling shaping is performed.
Further, in the predetermined section in which the rolling roll gap is widened and rolled and formed, the end surface of the material to be rolled and the hole peripheral surface may not be in contact with each other. However, when the end surface of the material to be rolled and the perforated peripheral surface are in one pass, there is a possibility that an uncompressed lower portion may remain at the rear end in the longitudinal direction of the material to be rolled. It may be necessary to increase the number of passes to adjust the shape. In such a case, double piece pass rolling may be performed in all passes in the second hole mold K2.

Moreover, FIG. 9 is a schematic explanatory diagram in the case of applying the double piece pass rolling in the rolling shaping with the fifth hole mold K5 (flat shaped hole mold) in the method for manufacturing the H-section steel according to the present embodiment. It is the schematic plan view seen from the upper part. For the sake of explanation, FIG. 9 shows a material A to be rolled before rolling shaping in a certain pass (left side in the figure) and after rolling shaping in the pass (right side in the figure).

As shown in FIG. 9, also in the flat hole type rolling in the fifth hole mold K5, the rolling shaping shown in FIG. 6 is performed from the start of rolling shaping until just before the end of rolling shaping, as in the edging rolling stage. For this reason, rolling shaping is performed with a roll gap necessary for the purpose. On the other hand, in the rolling modeling for the predetermined section L from the end of rolling modeling in the pass to the end of rolling modeling, the rolling modeling is performed with the roll gap widened. Specifically, the roll gap may be expanded stepwise so as to gradually reduce the amount of reduction immediately before the end of rolling shaping, or the roll gap may be greatly expanded so that the reduction amount is zero.

In the rolling shaping performed in this way, the rolling shaping is performed on the material A to be rolled in a state where the amount of reduction is small (or no amount of reduction) for the predetermined section L compared to other sections. In the longitudinal direction of the rolled material A, the flange part and the web part are not reduced so much. Therefore, even when the reduction ratio of the web portion is relatively large compared to the flange portion in the flat hole type rolling stage, the elongation of the web portion is elongated in the longitudinal direction of the material A to be rolled because the reduction rate itself is extremely small. Even if it exceeds the elongation of the flange portion, the so-called tongue-shaped defective portion (see FIG. 7B) is not formed remarkably as shown in FIG. That is, since the reduction amount in the predetermined section L is reduced or becomes zero at the rolling kick end, the growth of the cropped portion 92 as described above is suppressed. For this reason, it becomes possible to omit or simplify the intermediate crop cutting step as described above, and to improve the yield and the efficiency of rolling.

In addition, in order to perform reverse rolling also in the flat hole type rolling stage, rolling modeling is performed in a direction opposite to the direction shown in FIG. 9 in the next pass of the pass described in FIG. That is, the predetermined section L becomes a biting end in the next pass. At this time, since the roll gap allows a predetermined rolling modeling, the rolling modeling is applied to the predetermined section L as a biting end in this pass. That is, sufficient rolling modeling is performed for the predetermined section L as well. However, since the reduction amount for the predetermined section L in the next path of the path described in FIG. 9 needs to be added at the same time as the reduction amount in the next path, It is important to sufficiently examine the amount of reduction for the predetermined section L.

As described above, with reference to FIGS. 8 and 9, the case where the double piece pass rolling is applied in the edging rolling stage (FIG. 8) and the case where the double piece pass rolling is applied in the flat hole rolling stage (FIG. 9), respectively. explained. When applying the double piece pass rolling in the manufacturing method of the H-section steel according to the present embodiment, it is applied only to the edging rolling stage (that is, the rolling shaping corresponding to the first hole type K1 to the fourth hole type K4). Alternatively, it may be applied only to the flat hole rolling stage (that is, the rolling shaping corresponding to the fifth hole mold K5), and may be applied to both the edging rolling stage and the flat hole rolling stage. . In any case, the intermediate crop cutting step can be omitted or simplified, and the yield can be improved and the rolling efficiency can be improved.
In addition, when reverse rolling is employed in each rolling shaping stage, double-piece pass rolling may be applied in a predetermined arbitrary pass, or may be applied in all passes. From the viewpoint that it is desirable to suppress the growth of the cropped portion without forming the defective shape portion, it is desirable to apply double-piece pass rolling in all passes.

In addition, regarding the case where the double piece pass rolling described with reference to FIG. 8 and FIG. 9 is applied, the predetermined section L required to perform the rolling shaping with the roll gap widened can be arbitrarily set. For example, the sections L1 and L2 in the longitudinal direction of the material A to be rolled, which are formed with defective shape portions 90 and 92 in the conventional H-section steel manufacturing technology described with reference to FIGS. The predetermined section L is preferably set.

When determining the predetermined section L, it is necessary to clarify the boundary between the unsteady part and the steady part in rolling of the material A to be rolled, and to include at least the unsteady part in the predetermined section L. When the steady portion is included in the predetermined section L, the roll gap is widened in a partial range of the steady portion, and there is a possibility that a rolling reduction remains in the steady portion. However, since the influence of the reduction of the steady portion on the downstream path is small, it is preferable that the predetermined section L be in a range that includes the entire range of the unsteady portion and can be expanded to a part of the steady portion. Specifically, when the predetermined section L is determined, since it is determined based on all the elements such as the material cross section, the material to be rolled, the hole shape, the pass schedule, etc., each pass is performed by performing a laboratory experiment or an actual machine test. Each time the unsteady part length is measured, a suitable length is determined.

According to the manufacturing method of the H-section steel according to the present embodiment described above, the upper and lower ends (slab end surfaces) of the material A to be rolled are interrupted, and the respective parts divided into left and right by the interruption are bent left and right. By forming the flange part 80 by performing the processing, the H-shaped rough shaped member 13 can be formed without substantially lowering the upper and lower end surfaces of the material to be rolled A (slab) in the vertical direction. That is, compared with the conventional rough rolling method in which the end face of the slab is always squeezed, the flange width can be widened to form the H-shaped rough shape 13, and as a result, a final product having a large flange width ( H-shaped steel) can be manufactured.

Furthermore, in addition to the above-described effects, according to the method for manufacturing the H-section steel according to the present embodiment, an edging rolling stage (that is, rolling modeling corresponding to the first hole mold K1 to the fourth hole mold K4), and / or Alternatively, in the flat hole rolling stage (that is, rolling modeling corresponding to the fifth hole mold K5), the roll gap is widened at the time of rolling modeling with respect to the predetermined section L of the material A to be rolled (the tail end at the time of rolling modeling). By carrying out the double-piece pass rolling, it is possible to suppress the growth of the shape defect portion at the end portion in the longitudinal direction of the material to be rolled, which has been formed in the conventional H-section steel manufacturing technology. Thereby, the intermediate crop cutting process can be omitted or simplified, and the yield can be improved and the rolling efficiency can be improved. That is, most ideally, the rough rolling process, the intermediate rolling process, and the finish rolling process can all be performed without interposing the intermediate crop cutting process, and the crop cutting is performed in all processes (rough rolling process, intermediate rolling process, The removal of the crop portion generated in the longitudinal direction of the material to be rolled can be completed only by carrying out after the finish rolling step). In addition, if necessary, an intermediate crop cutting process is performed only on the web portion of the material to be rolled after the rough rolling process and before or during the intermediate rolling process (between rolling passes in the intermediate rolling process). Also good.

In particular, in the manufacture of large H-shaped steel products having a web height of 1000 mm or more or a flange width of 400 mm or more, the weight per unit length of the material A to be rolled is large and the product elongation during rolling is short. The proportion of the crop portion in the total length is large, and the growth of the crop portion tends to lead to a decrease in yield. Therefore, the technique for suppressing the growth of the crop portion according to the present embodiment is particularly useful in the manufacture of large H-section steel products.

As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the form of illustration. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

In the above embodiment, a technique for forming the material A to be rolled using the four hole molds of the first hole mold K1 to the fourth hole mold K4, and then performing the flat forming rolling using the fifth hole mold K5. However, the number of hole molds for performing the rough rolling process is not limited to this, and the rolling shaping process shown in the first hole mold K1 to the fourth hole mold K4 is performed using more hole molds. May be. That is, the hole shape configuration shown in the above embodiment is an example, and the number of hole shapes engraved in the sizing mill 3 and the rough rolling mill 4 can be arbitrarily changed, and the rough rolling process is preferably performed. It is suitably changed to such an extent that it can be performed.

In addition, although the slab has been described as an example of the material for manufacturing the H-section steel, the present invention is naturally applicable to other materials having similar shapes. That is, for example, the present invention can also be applied to the case where an H-shaped steel is manufactured by shaping a beam blank material.

The effect of the present invention will be verified using examples.
Below, first, the manufacturing method (henceforth the wedge method) which concerns on the conventional H-section steel manufacturing technique illustrated by patent document 1 grade | etc., And the manufacturing method (henceforth a split method also called this invention technique) are mentioned. The result of an experiment for comparing with the above is shown as Experimental Example 1. Then, in a split method, the result of an experiment comparing the application / non-application of the so-called “double piece pass rolling” described in the above embodiment is shown as Experimental Example 2.

(Experimental example 1)
As Reference Example 1, edging rolling was performed using a conventional H-shaped steel manufacturing technique based on the wedge method, and the crop length (crop length) at that time was measured. On the other hand, as Reference Example 2, edging rolling was performed by the split method using the first hole mold K1 to the third hole mold K3 shown in FIGS. 2 to 4, and the crop portion length at that time was measured. As a condition for this verification, the material slab cross section is 1800 mm × 300 mm, the wedge angle in the edging rolling in the embodiment is 30 ° in the first hole mold K1 and the second hole mold K2, and in the third hole mold K3. The angle was 90 °. The edging amount was the amount of reduction at the protrusion tip position (wedge tip position) in each hole mold.

FIG. 10 is a graph showing verification results of Reference Example 1 (the wedge method in the figure) and Reference Example 2 (the split method in the figure), and the edging amount (the amount of reduction by edging rolling) and the crop length in each case. It is a graph which shows the relationship. The description of G1 to G3 in FIG. 10 corresponds to the edging rolling in the first hole mold K1 to the third hole mold K3 according to the above embodiment. Moreover, the plot of FIG. 10 takes the average value of the crop length at both ends in the longitudinal direction of the material to be rolled.
As shown in FIG. 10, in Reference Example 1, the crop length grew almost in proportion to the edging amount. For example, when the edging amount was 600 mm, the crop length grew to about 250 mm.
On the other hand, in Reference Example 2, although some growth was observed in the crop length, the growth of the crop portion was not particularly observed in the second hole type K2 (G2 in the figure), and the growth of the crop length was compared with the comparative example. It can be seen that it is suppressed. For example, when the edging amount is 900 mm, the crop length remains about 80 mm.

(Experimental example 2)
As a comparative example, edging rolling was performed without applying double piece pass rolling by a split method using the first hole mold K1 to the fourth hole mold K4 shown in FIGS. 2 to 5, and both ends of the material to be rolled at that time The crop part length (crop length) was measured. FIG. 12 is a graph showing the measurement results of the comparative example, and two plots in the graph show the crop lengths at both ends in the longitudinal direction of the material to be rolled.

As an example, in the split method using the first hole type K1 to the fourth hole type K4 shown in FIGS. 2 to 5, the first hole type K1, the third hole type K3, the fourth hole type K4 ( Double piece pass rolling was performed in all passes of rolling shaping in G1, G3, and G4 in the drawing, and the lengths of the cropped portions (crop lengths) at both ends of the material to be rolled at that time were measured. FIG. 13 is a graph showing measurement results of Examples, and two plots in the graph indicate crop lengths at both ends in the longitudinal direction of the material to be rolled.
When performing double-piece pass rolling in the examples, the roll gap was expanded from about 400 mm at the end of the material to be rolled in each rolling pass, and the roll was opened at the final end.

The material slab used in the comparative examples and examples is a slab having a cross section of 2300 mm × 300 mm and a length of 4000 mm. Moreover, the rolling pass schedule in each hole type is as shown in Table 1 below.

However, the “roll gap” in Table 1 indicates the interval (distance) between the tip portions of the wedges (projections) of the hole-type upper and lower rolls, and is synonymous with the “edging amount” in Experimental Example 1 above. .

12 and 13, as can be seen from the comparison between FIG. 12 and FIG. 13, the amount of crop growth in each hole type is suppressed in the case of applying double-piece pass rolling (FIG. 13) compared to the case of non-application (FIG. 12). In particular, the amount of crop growth in G1, G3, and G4 (corresponding to the first hole type K1, the third hole type K3, and the fourth hole type K4) is greatly suppressed. The final crop length is about 40 mm or less when double-piece pass rolling is applied, and about 90 mm or less when non-application is applied. became.

According to the result of Experimental Example 2 described above, it can be seen that the growth of the crop length is greatly suppressed in the edging rolling stage in the manufacturing technique of the H-section steel to which the double piece pass rolling according to the present invention is applied. Thereby, rolling shaping can be implemented without performing the intermediate crop cutting process that has been performed constantly in the conventional H-section steel manufacturing technology. That is, improvement in yield and efficiency in rolling are realized.

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

DESCRIPTION OF SYMBOLS 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 shape material 14 ... Intermediate material 16 ... H-shaped steel product 20 ... Upper hole type roll (first hole type)
21 ... Preliminary hole type roll (first hole type)
25, 26 ... Projection (first hole type)
28, 29 ... Interrupt (first hole type)
30 ... Upper hole type roll (second hole type)
31 ... Pilot hole roll (second hole type)
35, 36... Projection (second hole type)
38, 39 ... Interrupt (second hole type)
40 ... Upper hole type roll (third hole type)
41 ... pilot hole type roll (third hole type)
45, 46 ... Projection (third hole type)
48, 49 ... Interrupt (3rd hole type)
50 ... Upper hole type roll (4th hole type)
51. Pre-hole type roll (fourth hole type)
55, 56 ... Projection (fourth hole type)
58, 59 ... Interrupt (4th hole type)
80 ... Flange part 82 ... Web part 85 ... Upper hole type roll (5th hole type)
86 ... Preliminary hole type roll (5th hole type)
90, 92 ... Crop-shaped part K1 ... 1st hole type K2 ... 2nd hole type K3 ... 3rd hole type K4 ... 4th hole type K5 ... 5th hole type (flat modeling hole type)
T ... Production line A ... Rolled material

Claims (11)

1. A method for producing an H-section steel comprising a rough rolling process, an intermediate rolling process, and a finish rolling process,
   The rolling mill that performs the rough rolling step is engraved with a plurality of five or more hole molds for rolling and shaping the material to be rolled,
   In the plurality of hole molds, one or a plurality of passes of the material to be rolled are formed,
   Of the plurality of hole molds, the first hole mold and the second hole mold are formed with protrusions that interrupt the vertical direction with respect to the width direction of the material to be rolled and form a split portion at the end of the material to be rolled,
   After the third hole type excluding the final hole type among the plurality of hole types, a protrusion that abuts against the interruption and sequentially bends the formed divided portion is formed.
   Of the plurality of hole molds, the final hole mold is a flat model hole mold,
   After the second hole mold excluding the final hole mold among the plurality of hole molds, the rolling is performed in a state where the end surface of the material to be rolled and the hole mold peripheral surface are in contact with each other in modeling of at least one pass.
   Rolling shaping is performed by expanding the rolling roll gap for a predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled in comparison with the rolling roll gap for other than the predetermined section in at least one pass of rolling shaping in the plurality of hole molds. The manufacturing method of H-section steel characterized by the above-mentioned.
2. 2. The method of manufacturing an H-section steel according to claim 1, wherein a tip end angle of the protrusions formed in the first hole mold and the second hole mold is 25 ° or more and 40 ° or less.
3. In all passes of rolling shaping with the first hole mold among the plurality of hole molds, the rolling roll gap for the predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled is wider than the rolling roll gap for other than the predetermined section. The method for producing an H-section steel according to claim 1 or 2, wherein the rolling shaping is performed.
4. Among all of the plurality of hole molds, at least in all passes of the rolling modeling in the third hole mold and the fourth hole mold, the rolling roll gap with respect to a predetermined section at the rear end portion in the rolling longitudinal direction of the material to be rolled is other than the predetermined section. The method for producing an H-section steel according to any one of claims 1 to 3, wherein the rolling shaping is performed in a manner wider than the rolling roll gap.
5. In rolling modeling with the second hole mold among the plurality of hole molds, in a pass where the rolling is performed in a state where the end face of the material to be rolled and the hole mold peripheral surface of the second hole mold are in contact with each other, The rolling shaping is performed by expanding a rolling roll gap with respect to a predetermined section at a rear end portion in the rolling longitudinal direction as compared with a rolling roll gap with respect to a portion other than the predetermined section, according to any one of claims 1 to 4. Manufacturing method of H-section steel.
6. In all passes of rolling shaping in the final hole mold among the plurality of hole molds, the rolling roll gap for the predetermined section at the rear end in the rolling longitudinal direction of the material to be rolled is expanded as compared with the rolling roll gap for other than the predetermined section. The method for producing an H-section steel according to any one of claims 1 to 5, wherein rolling shaping is performed.
7. In all passes of rolling shaping in all the hole types except the first hole type and the final hole type among the plurality of hole types, the rolling roll gap with respect to a predetermined section of the rolling longitudinal rear end portion of the material to be rolled is The method for producing an H-section steel according to any one of claims 1 to 6, wherein the rolling shaping is performed in a manner wider than a rolling roll gap for a portion other than the predetermined section.
8. The intermediate crop cutting step is performed only on the web portion of the material to be rolled after the rough rolling step and before the intermediate rolling step, according to any one of claims 1 to 7. The manufacturing method of the H-section steel of description.
9. The crop-shaped portion formed at the longitudinal end of the material to be rolled is removed for the first time after all of the rough rolling step, intermediate rolling step, and finish rolling step are completed. The manufacturing method of the H-section steel as described in any one of Claims.
10. The rolling mill that performs the rough rolling step is provided with a reduction mechanism that changes a roll gap of a hole roll of the rolling mill. Manufacturing method of H-section steel.
11. An H-section steel product manufactured by the method for manufacturing an H-section steel according to any one of claims 1 to 10,
    An H-shaped steel product having a web height of 1000 mm or more or a flange width of 400 mm or more.

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