JP2018176187A - H-shaped steel manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress centering defects and material passing defects which are problems in a molding technique in which a protrusion having an acute-angled tip shape is deeply interrupted on an end surface of a material and the formed flange portions are sequentially bent to stabilize rolling. Realize the conversion. SOLUTION: A rolling mill performing a rough rolling process is engraved with a plurality of hole molds for forming a material to be rolled, and the plurality of hole molds form interrupts at upper and lower ends of the material to be rolled in the width direction. The grooved hole type and one or more interrupt hole types in which a protrusion is formed to form a split portion at the end of the material to be rolled by vertically interrupting the width direction of the material to be rolled, and the interrupted hole type. , A plurality of bent hole types in which protrusions for sequentially bending the divided portions formed in the interrupt hole type are formed, and some or all of the protrusions formed in the interrupt hole type are predetermined. It is composed of a tip portion and a root portion having a height, and the tip portion is in contact with the material to be rolled when forming the divided portion, and the root portion is not in contact with the material to be rolled when forming the divided portion. [Selection diagram] FIG. 9

Description

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

  When manufacturing H-shaped steel, materials such as slabs and blooms extracted from the heating furnace are formed into rough shapes (so-called dog bone-shaped material to be rolled) by a rough rolling mill (BD), and intermediate universal rolling The thickness of the web and the flange of the above-mentioned rough shape is reduced by the machine, and at the same time the width reduction and the forging and shaping of the end face are applied to the flange of the material to be rolled by the edger rolling machine close to the intermediate universal rolling machine. . Then, the H-shaped steel product is shaped by the finishing universal rolling mill.

  In such a method of manufacturing an H-shaped steel, when forming a so-called dog bone-shaped rough shape from a slab material having a rectangular cross section, the end face of the slab is interrupted in the first hole type of the rough rolling process. After that, there is known a technique for dividing the interrupt in the second and subsequent hole types or for increasing the depth of the interrupt to perform edging rolling and for erasing the interrupt on the slab end surface in the hole type after that (for example, Patent Document 1).

  Further, for example, Patent Document 2 discloses a technique in which an end surface of a slab is interrupted to deepen the interruption sequentially, and then, it is pushed and expanded in a box hole type to form a flange equivalent portion of H-shaped steel.

JP-A-7-88501 Japanese Patent Application Laid-Open No. 60-21101

  In recent years, with the upsizing of structures and the like, production of large H-shaped steel products is desired. In particular, a product having a wider flange than that in the past, which greatly contributes to the strength and rigidity of the H-shaped steel, is desired. In order to manufacture an H-shaped steel product in which the flange is widened, it is necessary to form a material to be rolled having a wider flange width than in the past because of shaping in the rough rolling process.

  However, for example, in the technique disclosed in Patent Document 1 described above, the end face (slab end face) of a material such as a slab is interrupted, the end face is edged, and rough rolling is performed using the width spread. There is a limit to widening of the flange. That is, in order to increase the width of the flange in the conventional rough rolling method, the width spread can be improved by techniques such as wedge design (design of the interruption angle), pressure reduction adjustment, and lubrication adjustment. Because it does not contribute significantly, the width expansion ratio, which indicates the ratio of the amount of expansion of the flange width to the amount of edging, is about 0.8 even under the conditions where the efficiency at the initial stage of edging is the highest. Under repeated conditions, it is known that the flange width decreases as the amount of spread of the flange width increases, and finally becomes about 0.5. In addition, it is conceivable to enlarge the material itself such as slab and increase the edging amount, but there is a device limit in the equipment scale and rolling reduction amount of roughing mill, etc. and sufficient widening of product flange is not realized There is a situation.

  Further, for example, in the technology disclosed in Patent Document 2, the material such as the slab into which the interruption has been made is subjected to edging rolling by the box hole type having a flat bottom immediately without passing through, for example, the transition of the interruption shape. And the flange equivalent portion is formed, and in such a method, a shape defect is apt to occur as the shape of the material to be rolled is rapidly changed. In particular, the change in shape of the material to be rolled in such shaping is determined by the relationship between the force at the contact portion between the material to be rolled and the roll and the bending rigidity of the material to be rolled. In the case of manufacturing H-section steel, there is a problem that shape defects are more likely to occur.

  In view of the above circumstances, it is an object of the present invention to deeply interrupt the end face of a material such as a slab with an acute-tipped protrusion in the rough rolling process using a hole type for producing H-shaped steel, By sequentially bending the flange portion formed thereby, it is possible to suppress the occurrence of shape defects in the material to be rolled, and to efficiently and stably manufacture an H-shaped steel product having a wider flange width than conventional H. It is in providing the manufacturing method of a section steel.

  Furthermore, according to the present invention, in the rough rolling process, when the end face of a material such as a slab is deeply interrupted by a protrusion having an acute tip shape, groove deviation of a material to be rolled which causes a problem in a large rough shape An object of the present invention is to suppress the centering defect and the defect in the material passing and realize the stabilization of the rolling.

  In order to achieve the above object, according to the present invention, there is provided a method of manufacturing an H-shaped steel including a rough rolling process, an intermediate rolling process, and a finish rolling process, wherein the rolling process is performed on the rectangular cross-section material. In the machine, a plurality of hole molds for forming the material to be rolled are engraved, and in the plurality of hole molds, one or more pass molding is performed on the material to be rolled, and the plurality of hole molds are of the material to be rolled A grooved hole type for forming interruptions at the upper and lower ends in the width direction, and one or more projections formed with interruptions vertically in the width direction of the material to be cut to form divided portions at the end portions of the material to be rolled And a plurality of bending holes each having a projection which abuts against the interruption and which bends divided portions formed in the interruption hole sequentially. Among the parts, some or all of the protrusions have a predetermined height It comprises a tip portion and a root portion, and the tip portion contacts the material to be rolled when forming the divided portion, and the root portion does not contact the material to be rolled when forming the divided portion. There is provided a method of producing an H-shaped steel, characterized in that

  The shape of the root portion in the rolled cross section may be a shape having a substantially constant thickness in the vertical direction.

In the interruption hole type provided with a projection comprising the tip and the root, the tip angle of the tip is 30 ° or more and less than 50 °, the tip curvature of the tip is 10 mm or more and 30 mm or less, and the rectangle When the thickness of the cross-sectional material is 250 mm or more and 300 mm or less, rolling shaping may be performed so that the wedge projection width ratio W determined by the following equation (2) is 68% or less.
W = B1 / T (2)
However, it is B1: The maximum width length of a tip part, T: Thickness of a rectangular section material.

  A part or all of the interrupting hole mold may be provided with a hole-shaped side surface that abuts against the left and right side surfaces of the material to be rolled and restrains the material to be rolled from the left and right.

  The plurality of interrupting hole types are formed, and the plurality of interrupting hole types are composed of two types of interrupting hole types having different depths of interrupting in the width direction of the material to be rolled, and the two types of interrupting hole types Among them, the projection formed in the later-staged interrupt hole type may be composed of a tip and a root at a predetermined height.

  According to the present invention, in the rough rolling process using a hole type when manufacturing H-shaped steel, the end face of the material such as slab is deeply interrupted by the projection having an acute tip shape, and is thereby formed. By sequentially bending the flange portion, it is possible to suppress the occurrence of shape defects in the material to be rolled, and to efficiently and stably manufacture an H-shaped steel product having a wider flange width than in the prior art. Furthermore, it is possible to suppress the centering defect such as the groove shift of the material to be rolled which is a problem in such a shaping technology and the defect in the material passing, and to realize the stabilization of the rolling.

It is a schematic explanatory drawing about the manufacturing line of H section steel. It is a schematic explanatory drawing of a 1st hole type | mold. It is a schematic explanatory drawing of the 2-1st hole type | mold. It is a schematic explanatory drawing of the 2nd-2 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 the 5th hole type (flat modeling hole type). It is explanatory drawing which shows the outline of a groove | channel shift | offset | difference. It is a schematic explanatory drawing regarding the projection part shape after improvement. It is explanatory drawing of a wedge projection width. It is a graph which shows the relationship between a wedge projection width ratio and groove shift behavior. It is a schematic explanatory drawing of the hole-type structure which concerns on the modification of this invention. It is a schematic explanatory drawing regarding optimization of the projection part shape which concerns on this invention. It is a graph which shows the specific example regarding optimization of protrusion part shape.

  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 will be assigned the same reference numerals and redundant description will be omitted.

  FIG. 1 is an explanatory view of a production line T of H-shaped steel 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 in a production line T. Further, an edger rolling mill 9 is provided in proximity to the intermediate universal rolling mill 5. In the following, steel materials in the production line T may be collectively referred to as “rolled material A” for the sake of description, and the shapes thereof may be illustrated using broken lines, oblique lines, and the like as appropriate in each drawing.

  As shown in FIG. 1, in the production line T, a material to be rolled A such as a slab 11 extracted from the heating furnace 2 is roughly rolled in the sizing mill 3 and the rough rolling mill 4. Next, intermediate rolling is performed in the intermediate universal rolling mill 5. At the time of this intermediate rolling, an edger rolling machine 9 applies a pressure to an end portion or the like of a material to be rolled (a flange portion 80 described later) as needed. In a normal case, approximately 4 to 6 hole types are engraved on the rolls of the sizing mill 3 and the rough rolling mill 4, and the rough H shape is formed by reverse rolling of approximately several passes via these. The material 13 is formed, and a plurality of passes of reduction are applied to the H-shaped rough material 13 by using a rolling mill row consisting of two rolling mills of the intermediate universal rolling mill 5-edger rolling mill 9, and an intermediate material 14 Is shaped. Then, the intermediate material 14 is finish-rolled into a product shape in a finish universal rolling mill 8 to produce an H-shaped steel product 16.

  Next, a description will be given below of the configuration and shape of the holes formed in the sizing mill 3 and the rough rolling mill 4 shown in FIG. 1 with reference to the drawings. FIGS. 2 to 7 are schematic explanatory views of a sizing mill 3 for performing a rough rolling process and a hole type provided in the rough rolling mill 4. Here, all of the first through fourth hole types to be described may be engraved in, for example, the sizing mill 3, and the first through fifth hole types in the sizing mill 3 and the rough rolling mill 4 may be used. The hole type may be divided and engraved. That is, the first through fourth hole types may be engraved across both the sizing mill 3 and the roughing mill 4 or may be engraved in either one of the rolling mills. In the rough rolling process in the production of a normal H-section steel, shaping is performed in one or more passes in each of these hole types.

  Further, in the present embodiment, the basic configuration of the hole type to be engraved is described by exemplifying a six-hole type, but the number of the hole types is not necessarily the six-hole type, A plurality of six or more hole types may be used. That is, any hole-type configuration suitable for forming the H-shaped rough member 13 may be used. In addition, in FIGS. 2-7, the rough final pass shape of the to-be-rolled material A at the time of modeling in each hole type | mold is shown in figure by the 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 lower hole type roll 21 which are a pair of horizontal rolls, and the material to be rolled A is the gap between the upper hole type roll 20 and the lower hole type roll 21. It is pressed and shaped. Further, on the circumferential surface of the upper hole type roll 20 (that is, the upper surface of the first hole type K1), a protrusion 25 which protrudes toward the inside of the hole type is formed. Further, on the circumferential surface of the lower hole type roll 21 (that is, the bottom surface of the first hole type K1), a projection 26 projecting toward the inside of the hole type is formed. The protrusions 25 and 26 have a tapered shape, and the dimensions such as the projection length thereof are equal to each other by the protrusions 25 and the protrusions 26. The height (protruding 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 to be rolled A, and the interruptions 28 and 29 are formed. The first hole type K1 is also referred to as a "grooved hole type" because it is a hole type in which a groove (an interruption 28, 29) is provided on the end face of the slab. Here, it is desirable that the tip end angle (also referred to as a wedge angle) θ1a of the protrusions 25 and 26 be, for example, less than 50 °.

  Here, it is preferable that the hole width of the first hole type K1 be substantially equal to the thickness of the material to be rolled A (that is, the slab thickness). Specifically, the left-right centering property of the material to be rolled A is suitably secured by making the width of the hole mold at the tip of the protrusions 25 and 26 formed in the first hole mold K1 equal to the slab thickness. Be done. In addition, as shown in FIG. 2, the above-described protrusions are formed at the upper and lower end portions (slab end faces) of the material to be rolled A, as shown in FIG. The first hole is formed in the upper and lower ends of the upper and lower ends of the slab which are in contact with the material to be rolled A and which are divided into four elements (portions) by the interruptions 28, 29 It is preferable that no positive pressure reduction is performed on the top and bottom of the mold K1. The reduction by the upper surface and the bottom surface of the hole mold causes the elongation of the material to be rolled A in the longitudinal direction, thereby reducing the generation efficiency of the flange (a 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 end portions (slab end surfaces) of the material to be rolled A, and the pressure reduction at the protrusions 25 and 26 when the interruptions 28 and 29 are formed. The amount (wedge tip reduction amount) is made sufficiently larger than the reduction amount (slab end surface reduction amount) at the upper and lower ends of the slab, whereby the interruptions 28 and 29 are formed.

  FIG. 3 is a schematic explanatory view of the 2-1st hole type K2-1. The 2-1st hole type K 2-1 is engraved on the upper hole type roll 30 and the lower hole type 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 2-1st hole type K2-1), a projection 35 which protrudes toward the inside of the hole type is formed. Furthermore, on the circumferential surface of the lower hole type roll 31 (that is, the bottom surface of the 2-1st hole type K2-1), a projection 36 which protrudes toward the inside of the hole type is formed. The protrusions 35 and 36 have a tapered shape, and the dimensions such as the projection length thereof are equal to each other by the protrusions 35 and 36. The tip angle of the projections 35 and 36 is preferably a wedge angle θ 1 b less than 50 °. The protrusions formed in each hole type, such as the protrusions 35 and 36, may also be referred to as "wedge portions" or "wedges" in this specification.

  Here, the reason why the preferable numerical range of the wedge angle θ1b of the protrusions 35 and 36 should be less than 50 °, and the reason why the numerical value of the wedge angle θ1a of the first hole type K1 should also be a suitable numerical range accordingly Will be explained.

  The lower limit of the wedge angle is usually determined by the strength of the roll. The material A to be rolled is in contact with the rolls (upper hole type roll 30 and lower hole type roll 31 in the case of the 2-1 hole type K2-1, and upper hole type roll 20 and the lower hole type roll 21 in the first hole type K1) The heat received during that time expands the roll, and when the material to be rolled A separates from the roll, the roll is cooled and shrunk. These cycles are repeated during shaping, but if the wedge angle is too small, the thickness of the protrusions is so small that heat input from the material to be rolled A can easily enter from the left and right of the protrusions, and the roll becomes hotter It is easy to become. When the temperature of the roll becomes high, the thermal swing increases, so that heat cracks may occur, which may lead to roll breakage. For such reasons, it is desirable that both the wedge angles θ1a and θ1b be 25 ° or more, more preferably 30 ° or more.

On the other hand, when the wedge angles θ1a and θ1b increase, the wedge inclination angle increases, and thus the material A is easily pushed down by the frictional force in the vertical direction, and the inner surface portion of the flange equivalent portion at the time of interruption formation In the case of the formation in the 2-1st hole type K2-1 and later, the generation efficiency of the flange decreases. Therefore, it is desirable that the wedge angles θ1a and θ1b be less than 50 °.
The wedge angle θ1a of the first hole type K1 is preferably the same angle as the wedge angle θ1b of the second hole type K2 in the subsequent stage, in order to enhance the inductive property and secure the rolling stability.

  The height (protruding length) h2a of the protrusions 35 and 36 is set to be higher than the height h1 of the protrusions 25 and 26 of the first hole type K1, and h2a> h1. Further, it is preferable in terms of rolling dimension accuracy that the tip end angle of the protrusions 35, 36 is the same as the tip angle of the protrusions 25, 26 of the first hole type K1. The material to be rolled A after the first hole type K1 passing is further shaped in the roll gap between the upper hole type roll 30 and the lower hole type roll 31.

Here, the height h2a of the protrusions 35 and 36 formed in the 2-1st hole type K2-1 is higher than the height h1 of the protrusions 25 and 26 formed in the first hole type K1, Similarly, the penetration length into the upper and lower end portions (slab end face) of the material to be rolled A is longer in the case of the 2-1st hole type K2-1. The penetration depth of the protrusions 35 and 36 into the material to be rolled A in the 2-1st hole type K 2-1 is the same as the height h 2 a of the protrusions 35 and 36. That is, the penetration depth h1 'of the protrusions 25 and 26 into the material to be rolled A in the first hole type K1 and the material to be rolled A of the protrusions 35 and 36 in the 2-1st hole type K2-1. The penetration depth h2a of the is h1 '<h2a.
In addition, an angle θf formed by the upper surface 30a, 30b and the lower surface 31a, 31b of the material to be rolled A facing the upper and lower end portions (slab end surface) of the material to be rolled A and the inclined surfaces of the protrusions 35, 36 is shown in FIG. The four locations shown are each configured at about 90 ° (approximately right angle).

  As shown in FIG. 3, since the penetration length of the protrusion when pressed against the upper and lower end portions (slab end face) of the material to be rolled A is long, in the 2-1st hole type K2-1, The shaping is performed so that the interrupts 28, 29 formed in the single-hole type K1 are deeper, and the interrupts 38, 39 are formed. The (2-1) -hole type K2-1 is also referred to as an "interruption type".

  In addition, although forming in the 2-1st hole type K2-1 is performed by multiple passes, in the multi-pass shaping, the upper and lower end portions (slab end face) of the material to be rolled A and the opposite end in the final pass Modeling is performed such that the hole top surfaces 30a and 30b and the hole bottom surfaces 31a and 31b are in contact with each other. This is a portion corresponding to the flange (a portion corresponding to the flange portion 80 described later), assuming that the upper and lower end portions of the material to be rolled A do not contact with the inside of the hole type in all passes in the 2-1st hole type K2-1. It is because there is a possibility that a shape defect may occur such as forming asymmetrically left and right), and there is a problem in terms of threadability.

  FIG. 4 is a schematic explanatory view of the 2nd-2 hole type K2-2. The 2nd-2 hole type K2-2 is engraved on the upper hole type roll 40 and the lower hole type roll 41 which are a pair of horizontal rolls. On the circumferential surface of the upper hole type roll 40 (that is, the upper surface of the 2nd 2nd hole type K 2-2), a projection 45 which protrudes toward the inside of the hole type is formed. Furthermore, on the circumferential surface of the lower hole type roll 41 (that is, the bottom surface of the second 2nd hole type K 2-2), a projection 46 that protrudes toward the inside of the hole type is formed. The projections 45 and 46 have a tapered shape, and the dimensions such as the projection length thereof are equal to each other by the projections 45 and the projections 46. The tip angle of the projections 45 and 46 is preferably a wedge angle θ 1 b less than 50 °, and is designed to be the same angle as the wedge angle of the above-described 2-1-hole type K 2-1.

  The height (protrusion length) h2b of the protrusions 45 and 46 is set to be higher than the height h2a of the protrusions 35 and 36 of the above-mentioned 2-1st hole type K2-1, and h2b> h2a. . The rolled material A after the above-mentioned (2-1) -hole type K2-1 threading is further shaped in the roll gap of the upper hole type roll 40 and the lower hole type roll 41.

Here, from the height h2a of the protrusions 35 and 36 formed in the 2-1st hole type K2-1, the height h2b of the protrusions 45 and 46 formed in the 2nd-2nd hole type K2-2 The penetration length to the upper and lower end portion (slab end face) of the material to be rolled A is also longer in the second 2-2 hole type K2-2. The penetration depth of the protrusions 45 and 46 into the material to be rolled A in the second 2-2 hole type K 2-2 is the same as the height h 2 b of the protrusions 45 and 46. That is, the penetration depth h2a of the protrusions 35 and 36 into the material to be rolled A in the 2-1st hole type K2-1, and the rolled portions 45 and 46 in the 2nd-2nd hole type K2-2. The penetration depth h2b into the material A is in a relationship of h2a <h2b.
Further, in FIG. 4, an angle θf formed by the upper surface 40a, 40b and the lower surface 41a, 41b of the material to be rolled A facing the upper and lower end portions (slab end surface) of the material to be rolled The four locations shown are each configured at about 90 ° (approximately right angle).

As shown in FIG. 4, since the penetration length of the projection when pressed against the upper and lower end portions (slab end face) of the material to be rolled A is long, in the 2-2nd hole type K2-2, The shaping is performed so that the interrupts 38 and 39 formed in the 2-1 hole type K2-1 are deeper, and the interrupts 48 and 49 are formed. The 2nd-2 hole type K2-2 is also referred to as an "interruption type".
In addition, 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 interruptions 48 and 49 formed here.

  Moreover, although shaping | molding in the 2nd 2-hole type | mold K2-2 is performed by multiple passes, in the said multipass shaping, it opposes it with the upper-and-lower-end part (slab end surface) of the to-be-rolled material A in the final pass. Modeling is performed such that the hole top surfaces 40a and 40b and the hole bottom surfaces 41a and 41b are in contact with each other. This is a portion corresponding to the flange (a portion corresponding to the flange portion 80 described later), assuming that the upper and lower end portions of the material to be rolled A do not contact with the inside of the hole type in all passes in the 2nd-2 hole type K2-2. It is because there is a possibility that a shape defect may occur such as forming asymmetrically left and right), and there is a problem in terms of threadability.

  FIG. 5 is a schematic explanatory view of the third hole type K3. The third hole type K3 is engraved on the upper hole type roll 50 and the lower hole type roll 51 which are a pair of horizontal rolls. On the circumferential surface of the upper hole type roll 50 (that is, the upper surface of the third hole type K3), a projection 55 which protrudes toward the inside of the hole type is formed. Furthermore, on the circumferential surface of the lower hole type roll 51 (that is, the bottom surface of the third hole type K3), a protrusion 56 that protrudes toward the inside of the hole type is formed. The protrusions 55 and 56 have a tapered shape, and the dimensions such as the projection length thereof are equal to each other by the protrusions 55 and the protrusions 56.

The tip angle θ2 of the protrusions 55 and 56 is wider than the angle θ1 b, and the penetration depth h3 of the protrusions 55 and 56 into the material to be rolled A is the penetration depth of the protrusions 45 and 46. It is shorter than h2b (ie, h3 <h2b). The angle θ2 is preferably, for example, 70 ° or more and 110 ° or less.
Further, an angle θf formed by the upper surface 50a, 50b and the lower surface 51a, 51b of the material to be rolled A facing the upper and lower end portions (slab end surface) and the inclined surface of the protrusions 55, 56 is shown in FIG. The four locations shown are each configured at about 90 ° (approximately right angle).

  As shown in FIG. 5, in the third hole type K 3, the second to third hole type K 2-2 passes through the material to be rolled A at the upper and lower end portions (slab end surface) of the material to be rolled A The interruptions 48 and 49 formed in the two-hole type K2-2 become interruptions 58 and 59 when the projections 55 and 56 are pressed. That is, in the final pass in the formation in the third hole type K3, the deepest portion angle (hereinafter also referred to as an interrupt angle) of the interrupts 58 and 59 is θ2. In other words, shaping is performed such that the divided portion (portion corresponding to the flange portion 80 described later) shaped together with the formation of the interruptions 48 and 49 in the 2nd-2 hole type K2-2 is bent outward. The third hole type K3 is also referred to as a "bent hole type".

  The third hole K3 shown in FIG. 5 is shaped by at least one pass or more, and at least one pass or more of these are formed by the upper and lower end portions (slab end face) of the material to be rolled A It is carried out in a state in which the top and bottom surfaces of the three-hole type K3 are in contact with each other. In the state where the upper and lower end portions (slab end faces) of the material to be rolled A and the inside of the hole mold are in contact with each other, light reduction of the end portions is preferably performed.

  FIG. 6 is a schematic explanatory view of the fourth hole type K4. The fourth hole type K4 is engraved on the upper hole type roll 60 and the lower hole type roll 61, which are a pair of horizontal rolls. On the circumferential surface of the upper hole type roll 60 (that is, the upper surface of the fourth hole type K4), a projection 65 projecting toward the inside of the hole type is formed. Further, on the circumferential surface of the lower hole type roll 61 (that is, the bottom surface of the fourth hole type K4), a projection 66 projecting toward the inside of the hole type is formed. The projections 65 and 66 have a tapered shape, and the dimensions such as the projection length thereof are equal to each other by the projections 65 and the projections 66.

The tip end portion angle θ3 of the projection 65, 66 is wider than the angle θ2, and the penetration depth h4 of the projection 65, 66 into the material to be rolled A is the penetration depth of the projection 55, 56 It is shorter than h3 (ie, h4 <h3).
In addition, the angle θf formed by the upper surfaces 60a and 60b and the lower surfaces 61a and 61b of the material to be rolled A and the inclined surfaces of the protrusions 65 and 66 is the third one. Similar to the hole type K3, all four places shown in FIG. 6 are configured at about 90 ° (approximately right angle).

In the fourth hole type K4, the interruptions 58 and 59 formed in the third hole type K3 at the upper and lower end portions (slab end faces) of the material to be rolled A after passing the third hole type K3 are used. The projections 65 and 66 are pushed and spread out to form interruptions 68 and 69, respectively. That is, in the final pass of the formation in the fourth hole type K4, the deepest part angle (hereinafter also referred to as an interruption angle) of the interruptions 68 and 69 is θ3. In other words, the third hole type K3 is shaped such that the divided portion (portion corresponding to the flange portion 80 described later) shaped together with the formation of the interruptions 58 and 59 is further bent outward. The fourth hole type K4 is also referred to as a "bent hole type".
The portions of the upper and lower end portions of the material to be rolled A shaped in this manner are portions corresponding to the flange of the H-shaped steel product to be described later, and will be referred to as the flange portion 80 here.

  The formation in the fourth hole type K4 shown in FIG. 6 is performed by at least one pass or more, and at least one pass or more of them are the upper and lower end portions (slab end face) of the material to be rolled A and the inside of the hole type (fourth hole) It takes place with the top and bottom surfaces of the mold K4 in contact. In the state where the upper and lower end portions (slab end faces) of the material to be rolled A and the inside of the hole mold are in contact with each other, light reduction of the end portions is preferably performed.

  FIG. 7 is a schematic explanatory view of the fifth hole type K5. The fifth hole type K5 is composed of an upper hole type roll 85 and a lower hole type roll 86 which are a pair of horizontal rolls. As shown in FIG. 7, in the fifth hole type K5, the material to be rolled A shaped up to the fourth hole type K4 is rotated 90 ° or 270 °, and up to the fourth hole type K4, the material to be rolled is A The flange portions 80 located at the upper and lower ends are arranged to be on the rolling pitch line. Then, in the fifth hole type K5, the flange width is adjusted by reducing the pressure of the web portion 82 which is a connection portion connecting the two flange portions 80 and pressing the flange front end portion of the flange portion 80. In this manner, a so-called dog-bone shaped H-shaped rough section (H-shaped rough section 13 shown in FIG. 1) is formed. The fifth hole type K5 is also referred to as a "web reduced thickness hole type" or a "flat shaped hole type" because the fifth hole type K5 presses the web portion 82 to reduce the thickness. In addition, the rolling formation in this flat formation hole type | mold (5th hole type | mold K5) is performed by 1 or arbitrary multiple passes.

  Reverse rolling of a plurality of passes is carried out using a rolling mill row consisting of two rolling mills of an intermediate universal rolling mill 5-edger rolling mill 9 which is a known rolling mill, with respect to the H-shaped rough section 13 shaped in this way Is added, and the intermediate material 14 is shaped. Then, the intermediate material 14 is finish-rolled into a product shape in a finish universal rolling mill 8 to produce an H-shaped steel product 16 (see FIG. 1).

  As described above, the upper and lower end portions (slab end faces) of the material to be rolled A are interrupted using the first through fourth hole types K1 to K4 according to the present embodiment, and each of the left and right parts are separated by the interruptions. By forming the flange 80 by forming the flange portion 80 by bending the portion left and right, the width of the flange is made wider compared to the conventional rough rolling method in which the slab end face is always pressed down, and the H shape is formed It becomes possible to shape the material 13, and as a result, it is possible to produce a final product with a large flange width (H-shaped steel).

Here, in the forming method using the first through fourth hole types K1 to K4 described above, particularly, the forming in the interruption hole type such as the 2-1st hole type K2-1 and the 2-2nd hole type K2-2 In the upper and lower end portions (slab end faces) of the material to be rolled A, positive pressure reduction is not performed without bringing the hole form and the material to be rolled A into contact as much as possible. This is to cause the rolling of the material A to be elongated in the longitudinal direction by the pressure reduction, and to avoid the reduction of the generation efficiency of the flange equivalent portion (that is, the later flange portion 80). Furthermore, in the 2-1st hole type K2-1 and 2-2nd hole type K2-2, the configuration in which the side surface of the material to be rolled A is restrained by the hole type is not adopted, and the left-right direction of the material to be rolled A There is a concern about centering defects such as groove slippage.
In addition, the third hole type K3 and the fourth hole type K4 do not adopt a configuration in which the side surface of the material to be rolled A is restrained by the hole type, so that centering defects such as the groove displacement can not be eliminated. There is a risk of failure.
The groove shift means that the center of the formed interrupt is formed when forming an interrupt by the projection in rolling and shaping with the 2nd-1 hole type K2-1 and the 2nd-2 hole type K2-2. This is a phenomenon in which the center of the rolled material A deviates from the center in the width direction (see FIG. 8).

  The present inventors further study the conditions that cause centering defects such as groove misalignment in the above-mentioned No. 2-1 hole type K2-1 and No. 2-2 hole type K2-2, and obtain the following findings. The That is, for the inductive property of the material to be rolled A by the protrusions 35, 36 (45, 46) in the 2-1st hole type K2-1 and the 2-2nd hole type K2-2, the protrusions 35, 36 ( The rolling resistance (frictional resistance) according to 45, 46) is concerned, and the inductive property changes according to the frictional resistance of the tip portion and the side portion of the projection 35, 36 (45, 46). Specifically, for example, when the curvatures of the tip portions of the protrusions 35, 36 (45, 46) are the same, the driving lengths (interruption lengths) of the protrusions 35, 36 (45, 46) due to the progress of the rolling pass The longer the), the greater the frictional resistance of the side portions of the protrusions 35, 36 (45, 46). If there is an element (temperature, roll set-up, etc.) that impairs the symmetry of rolling under the condition that the rolling resistance by such projections 35, 36 (45, 46) is increased, it is proportional to the above-mentioned frictional resistance As a result, it is considered that a centering failure such as a groove shift occurs.

  In view of such knowledge, the inventors of the present invention relate to the rolling resistance (frictional resistance) by the protrusions 35, 36 (45, 46), and the conductivity of the material to be rolled A is 35 36 (45, 46) focusing on the fact that the inductive property changes in accordance with the frictional resistance of the tip portion and the side portion, and devising the shape of the protrusions 35, 36 (45, 46) We devised a technology to reduce the frictional resistance of the side part. In the following, with reference to FIGS. 9 to 10, a hole type capable of improving the shape of the projection formed in the interruption hole type and reducing the frictional resistance between the projection and the material to be rolled The configuration will be described. In addition, below, the case where the shape of the projection parts 45 and 46 formed in the 2-2nd hole type K2-2 hole type of the interruption hole type was improved among the hole type structure demonstrated above was illustrated is illustrated. explain.

FIG. 9 is a schematic explanatory view related to the shape of the projection after the improvement, and the shape of the projections 45 and 46 is improved in the second 2-2 hole type K2-2 described in the present embodiment, and the projection 45 is obtained. It is explanatory drawing which shows the structure at the time of setting it as "and 46". FIG. 9 also shows an enlarged view in which the vicinity of the upper protruding portion 45 'is enlarged.
As shown in FIG. 9, the improved projections 45 'and 46' do not have a tapered shape and have a substantially uniform thickness, with a tapered tip 45a (46a) protruding toward the inside of the hole mold. As shown in the figure, a relief portion 90 is formed on the side of the root portion 45b (46b) such that the material to be rolled A and the inner surface of the hole are not in contact with each other. It will be That is, in the protrusions 45 ′ and 46 ′ after the improvement, the section (height h) of the tip 45 a (45 b) in contact with the material to be rolled A in the height direction of the protrusions and the non-contact root It is divided into a section 45b (46b) (height h '), and in the section of height h', a relief 90 is formed on the side of the root 45b (46b). The tip end angle (wedge angle) of the tip end 45a (46a) is set to θ1b as before.

  In the interruption hole type having the configuration according to the improved projections 45 ′ and 46 ′ described with reference to FIG. 9 as described above, the side surface of the projection and the material to be rolled A are compared with the configuration according to the conventional projections 45 and 46. The contact length with (hereinafter simply referred to as contact length) is short. Specifically, comparing the hole-type configuration according to FIG. 4 with the hole-type configuration according to FIG. 9, the contact length on one side surface of the conventional protrusions 45 and 46 is h2b / cos (θ1b / 2) On the other hand, the contact length on one side of the improved projections 45 ′, 46 ′ is h / cos (θ 1 b / 2). As shown in FIG. 9, since h2b> h, it is clear that the contact length at the improved protrusion is shorter than the previous contact length.

  As described above, the inducibility of the material to be rolled A in the interruption hole type is related to the rolling resistance (frictional resistance) by the protrusions, and the inducibility according to the friction resistance of the tip portion and the side portion of the protrusions. Is known to change. According to the hole type configuration provided with the improved projections 45 ′ and 46 ′ shown in FIG. 9, the contact length at the improved projections is shorter than the contact length in the prior art. The rolling resistance (frictional resistance) due to the projections is reduced as compared with the above configuration, and the improvement of the inductive property of the material to be rolled A is realized. With the improvement of the inductive property, it becomes possible to suppress centering defects such as groove slippage and defects in material passing, and to improve rolling stability.

  Here, with regard to the improved projections 45 ′ and 46 ′ as shown in FIG. 9, the present inventors have improved the dimensionality and the like for further improving the induction (passability) of the material to be rolled A. We considered it to exist and conducted further studies. Specifically, when the wedge angle θ 1 b and the wedge tip curvature R, etc. were set to predetermined conditions, the preferred range of the maximum width B 1 of the tip 45 a (46 a) was examined. When predetermined conditions such as the wedge angle θ1b and the wedge tip curvature R are determined, the height h of the tip 45a (46a) and the root 45b (46b) of the improved projections 45 ′ and 46 ′ The value of height h 'is uniquely determined if B1 is determined.

In order to determine the preferable range of the maximum width B1 of the tip 45a (46a), the present inventors evaluate centering defects such as groove misalignment which may occur due to rolling formation with an interruption hole type and defects in passing The wedge projection width ratio W was defined as an index to be used, and the value of the wedge projection width ratio W and the groove shift behavior (the behavior regarding the centering property) were examined. The wedge projection width ratio W is expressed by the following equation (1).
W = B / T (1)
B: Wedge projection width, T: Slab thickness FIG. 10 is an explanatory view of the wedge projection width B, which is an enlarged view of the vicinity of the projection of the interrupting hole type in a predetermined pass.

Table 1 shows groove deviation behavior when the wedge angle θ 1 b (simply described as an angle in the table), wedge tip curvature R, wedge height H, and slab thickness T are changed in the rolling forming in the interrupt hole type It is data which shows a relation. FIG. 11 is a plot of the data described in Table 1, and is a graph showing the relationship between the wedge projection width ratio W and the groove displacement behavior. Incidentally, as the description of the groove shift behavior in Table 1 and FIG. 11, +1 indicates that the groove shift behavior is good, 0 indicates that the groove shift behavior is within the allowable range, and −1 indicates the groove shift behavior Indicates the case where the fluctuation is large (i.e., the case of a centering failure).
When the groove displacement behavior is within the allowable range (Table 1, groove displacement behavior 0 in FIG. 11), specifically, although groove displacement occurs at the time of rolling and shaping, the groove displacement amount is 30 mm or less, The drawing shows the case where the dimensional correction can be made by the rolling process in the subsequent hole type (for example, the third hole type K3 and the fourth hole type K4), the intermediate universal rolling mill 5 and the finishing universal rolling mill 8.
In Table 1 and FIG. 11, the wedge angle θ 1 b was 30 to 50 °, the wedge tip curvature R was 10 to 30 mm, and the slab thickness T was 250 to 300 mm.

  Geometrically, even in the same roll gap state, the wedge projection width B tends to increase and the wedge projection width ratio W tends to increase as the wedge angle θ 1 b increases. Similarly, as the wedge tip curvature R increases, the wedge projection width B tends to increase and the wedge projection width ratio W tends to increase. In addition, as the slab thickness T decreases, the wedge projection width ratio W tends to increase.

In addition, as shown in Table 1 and FIG. 11, according to this experiment and examination, under the condition that the wedge projection width ratio W is set within the range of 68% or less, the wedge angle θ1b, the wedge tip curvature R Regardless of the values of the wedge height H and the slab thickness T, the groove shift behavior is good (+1 in Table 1 and FIG. 11), and the stabilization of the rolling is realized.
On the other hand, under the condition that the wedge projection width ratio W is set within the range of 68% to 82%, the case where the groove displacement behavior is within the allowable range and the case where the fluctuation is large are mixed, The centering defect and the passing defect are not sufficiently suppressed, and the rolling can not be stabilized.
Furthermore, under the conditions where the wedge projection width ratio W is set in the range of more than 82%, the groove shift behavior is largely fluctuated, and the rolling can not be stabilized.

  As described with reference to Table 1 and FIG. 11, under the condition that the wedge angle θ 1 b is 30 ° or more and less than 50 °, the wedge tip curvature R is 10 to 30 mm, and the slab thickness T is 250 to 300 mm By setting the width ratio W within the range of 68% or less, it can be seen that the groove shift behavior is well maintained and the stabilization of rolling is realized.

The above-described conditions concerning the wedge projection width ratio W are applied to the hole-type configuration having the improved projections 45 ′ and 46 ′ according to the present embodiment, and the maximum width B 1 of the tip 45 a (46 a) is It is understood that it is preferable to set the length such that the wedge projection width ratio W (= B1 / T) determined by the following equation (2) is in the range of 68% or less.
W = B1 / T (2)
Under the condition that the wedge angle θ 1 b, the wedge tip curvature R, and the slab thickness T are fixed, the preferred maximum width B1 of the tip 45 a (46 a) is determined, and the preferred height of the tip 45 a (46 a) is also determined. It will be decided. That is, since the height h of the tip 45a (46a) shown in FIG. 9 is fixed and the height h2b of the entire projection 45 (46) is also fixed, the height h 'of the root 45b (46b) is also fixed. It will be decided. Since the height of the relief portion 90 is the same value as the height h 'of the root 45b (46b), the groove shift behavior is well maintained (ie, the wedge projection width ratio W (= B1 / T) is 68). The value of the height h 'of the relief portion 90 which becomes less than%) is determined.

  Further, the maximum width length B1 of the tip portion 45a (46a) in the hole type configuration having the improved projections 45 ′, 46 ′ according to the present embodiment is the protrusion 25 formed in the first hole type K1. , And 26 must be designed to be larger than the maximum width B2 (see FIG. 2). This is a rolling shaping (so-called interruption) in which the interruption formed in the previous stage is further deepened when the maximum width B1 of the tip 45a (46a) is equal to or less than the maximum width B2 of the protrusions 25, 26. It is because there is a possibility that rolling shaping can not be realized.

  According to the manufacturing method of the H-shaped steel which carries out rolling shaping by the interruption hole type provided with the projection parts 45 'and 46' after the improvement explained above, the 2-1st hole type K2-1 and the 2-2nd hole It is possible to reduce the frictional resistance between the projection and the material to be rolled A as compared with the conventional interruption hole type in the rolling and forming with the interruption hole type such as the shape K2-2, particularly the 2-2nd hole type K2-2. As a result, it is possible to improve the conductivity of the material to be rolled A, to suppress centering defects such as groove slippage and defects in material passing, and to improve the stability of rolling. Specifically, the wedge projection width ratio W (= B1 / T) is obtained under the condition that the wedge angle θ 1 b is 30 ° or more and less than 50 °, the wedge tip curvature R is 10 to 30 mm, and the slab thickness T is 250 to 300 mm. By setting the height h 'of the escape portion 90 (= the height h' of the root 45b (46b)) so as to be within a suitable range (68% or less), centering defects such as groove misalignment or threading Defects can be suppressed, and rolling stability can be improved.

  For example, when manufacturing a H-shaped steel product having a flange width of 450 mm using a material having a slab thickness T of 250 mm, the product flange piece width is about 225 mm. The flange piece width is preferably shaped to a desired value in the rough rolling process in view of rolling and shaping, so that the flange width after the rough rolling process is a slab thickness of 250 mm + piece width 225 mm × 2 = 700 mm. Here, the wedge projection width B is 700 mm × 1⁄2 × sin (30 ° / 2) × 2 ≒ 181 mm when the wedge angle is 30 °. The wedge projection width ratio W at this time is 18 1/250 0.7 0.73, which is not within the range described in the present embodiment (68% = 0.68 or less), and a range in which the groove shift behavior occurs. (See FIG. 11). In such a case, by applying the interrupting hole type design provided with the improved projections 45 ′ and 46 ′ described in the present embodiment and performing rolling shaping, the value of the wedge projection width ratio W is increased. And the improvement of the rolling stability is realized.

  Further, for example, in the case of manufacturing an H-shaped steel product having a flange width of 500 mm using a material having a slab thickness T of 300 mm, the manufacturing flange piece width is 250 mm. The flange piece width is preferably shaped to a desired value in the rough rolling process in view of rolling and shaping, so that the flange width after the rough rolling process is a slab thickness of 300 mm + half width 250 mm × 2 = 800 mm. Here, the wedge projection width B is 800 mm × 1⁄2 × sin (30 ° / 2) × 2 ≒ 207 mm when the wedge angle is 30 °. The wedge projection width ratio W at this time is 207/300 = 0.69, which is not within the range described in the present embodiment (68% = 0.68 or less), and a range in which the groove shift behavior occurs. (See FIG. 11). In such a case, by applying the interrupting hole type design provided with the improved projections 45 ′ and 46 ′ described in the present embodiment and performing rolling shaping, the value of the wedge projection width ratio W is increased. And the improvement of the rolling stability is realized.

  Although the example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is obvious that those skilled in the art can conceive of various modifications or alterations within the scope of the idea described in the claims, and they are naturally within the technical scope of the present invention. It is understood that.

  For example, in the above embodiment, the material to be rolled A is shaped using the group of holes shown and described as the first through fourth holes K1 to K4, and then the fifth hole K5 is used. Although the technique for performing flat shape rolling has been described, the number of hole types for carrying out the rough rolling process is not limited to this, and it may be carried out using more hole types. 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 process is preferably performed. It is suitably changed to the extent that it can do.

  Further, in the above embodiment, it has been described that the 2-1 hole type K2-1 and the 2-2 hole type K2-2 having different wedge heights are engraved as the interrupt hole type. In that case, as described above, the protrusions 45 'and 46' may be formed in the improved shape in the 2-2nd hole type K2-2, and the protrusions of the same shape may be formed in the 2-1st hole. It may also be formed in the mold K2-1. In particular, the projections formed on the second 2-2 hole type K2-2 in the latter stage have an improved shape (projections 45 'and 46'), so that the material to be rolled A is sufficient at the final stage of the interruption rolling. Since the inducibility can be secured, the rolling stability can be further enhanced.

  Further, the interruption hole type may be only one hole type, and the improvement described in the above embodiment may be applied to the protrusion formed in the interruption hole type. When the size of the H-shaped steel product to be manufactured is not so large, even if it is a hole type configuration in which the interruption hole type is a single hole type, rolling and forming with sufficient dimensional accuracy is possible, and the hole type The roll cylinder width can be greatly reduced and the roll cylinder width can be made more efficient with respect to the rolls to be engraved.

(Modification of the present invention)
In the above embodiment, although the case where the 2-1st hole type K2-1 and the 2-2nd hole type K2-2 having different wedge heights are engraved as the interruption hole type is illustrated and described, In the case of the hole type, since the side of the material to be rolled A is not restrained by the hole type, centering defects such as groove displacement in the left and right direction of the material to be rolled A may be concerned. The problem is that the thickness of the corresponding portion becomes uneven in the vertical and horizontal directions, and in particular, the flange left and right thickness tends to be different. In particular, for example, in the case where the difference between the height of the projection of the 2-1st hole type K2-1 and the height of the projection of the 2-2nd hole type K2-2 is large in order to form the flange width to 500 mm or more, Such problems are likely to occur when manufacturing a large H-shaped steel product having a product flange width of 400 mm or more from a material having a thickness of less than 260 mm.
In addition, it may be considered that only one hole type can be formed for the interruption hole type due to the roll body length restriction and the like. In such a case, the inductive property of the material to be rolled becomes insufficient, and the thickness of the flange equivalent portion to be formed becomes uneven in the vertical and horizontal directions due to groove displacement or the like, and in particular, the difference in the flange left and right thickness There are concerns about problems that arise.

  In view of the above problems, as a modified example of the present invention, a configuration in which the side surfaces of the hole formed on the left and right of the interrupting hole shape abut against the material to be rolled A (so-called bag holes) Mold shape) is devised.

  FIG. 12 is a schematic explanatory view of a hole-type structure according to a modification of the present invention, in which the improved projection shape described in the above embodiment is applied to the so-called blind hole type interrupt hole mold 120. It is the schematic of a case. As shown in FIG. 12, in the blind hole type interrupting hole mold 120, the hole side surfaces 122 and 123 are formed on the left and right of the hole mold so as to restrain the material to be rolled A.

The contact points of the material to be rolled A with the side surfaces 122 and 123 of the material to be rolled are shaped by the first hole type K1 and are the thickest in the thickness of the material to be rolled A immediately after being introduced into the interrupting hole mold 120 Preferably, the location is near the central portion of the outer surface of the flange equivalent portion of the material to be rolled A (the subsequent flange portion 80).
Further, in the hole type configuration shown in FIG. 12, the shape of the hole side surfaces 122 and 123 is a vertical shape perpendicular to the hole type roll axis from the viewpoint of efficiently constraining the material to be rolled A from the left and right. Although it is preferable, in order to facilitate the repair of the roll due to roll wear, it is desirable that the shape has a taper angle of, for example, about 5 to 10% with respect to the vertical direction.

  By adopting a configuration in which the hole side surfaces 122 and 123 shown in the interruption hole mold 120 according to the present modification are brought into contact with the side surfaces of the material to be rolled A, the effect of improving the inductive property described in the above embodiment In addition to the effects, the thickness of the flange equivalent portion to be formed becomes uneven in the vertical and horizontal directions, and shape defects such as a difference between the left and right flange thickness are particularly suppressed, and the improvement of the product dimensional accuracy is realized. In particular, in the case where only one hole type is used as the interrupting hole type and a large H-section steel having a wide flange width is manufactured, further rolling stabilization can be achieved by adopting the hole type shape according to this modification of the side wall constraint type. .

  Further, in the above embodiment, referring to FIG. 9, as the improved protrusion shape, it has a tapered shape tip portion 45a (46a) protruding toward the inside of the hole mold and does not have a taper shape and has a substantially thickness. The shape which consists of root part 45b (46b) of the shape which is fixed is illustrated, and it explains that escape part 90 is formed by such shape. However, such a shape of the root 45b is an example of the present invention, and various shapes can be designed such that the root 45b is not in contact with the material to be rolled at the time of interruption. Here, optimization of the thickness (also referred to as the wedge width) of the root 45b will be briefly described.

FIG. 13 is a schematic explanatory view regarding the optimization of the protrusion shape according to the present invention. The shape of the root 45b is preferably designed so that the stress generated in the root 45b during rolling and shaping becomes constant. When the center of the material to be rolled A and the center of the projection are shifted and bitten, the offset P is applied to the tip 45a. In the illustrated interrupting hole type, when the wedge height of the previous interrupting hole type is L, the wedge width is Y1, and the range in which stress is applied in the rolling direction is b, the wedge height from the wedge tip is L The stress σ 1 is expressed by the following equation (3).
σ1 = 6 PL / (bY1 ² ) (3)

In the illustrated interrupting hole type, when the relief portion is provided so that the material to be rolled A and the wedge side surface do not contact, for example, the thickness of the root 45b is the same as the wedge width Y1 of the interrupting hole type in the previous stage In this case, the applied stress gradually increases as it approaches the root (root) of the wedge, and when the wedge height at any position is X, it increases in proportion to the height X.
Therefore, the dimension item that can be changed is the wedge width Y, considering the shape of the root portion 45b such that the value of the stress σ is constant regardless of the value (position) of the wedge height X. Assuming that the stress value σ is constant at σ1, the following equation (4) holds.
Y ² = 6 PX / (bσ 1) (4)
Furthermore, the following equation (5) holds from the above equation (3).
Y ² = (X / L) Y 1 ² (5)
That is, the wedge width Y is preferably determined to be proportional to the wedge height X ^0.5 .
In addition, such a way of thinking holds when the roll shape is the same in the rolling direction, and since the roll shape is exactly cylindrical, the stress generated is completely constant regardless of the wedge height. Although it does not become, it can be said that the fluctuation of stress is greatly improved with respect to the conventional shape.

  FIG. 14 is a graph showing a specific example concerning the optimization of the above-mentioned protrusion shape, and in the case where the height of the interrupt hole type wedge of the former stage is 200 mm and the wedge tip angle is 30 °, the improved interrupt of the latter stage It is the graph which calculated about the shape for making the stress which generate | occur | produces in the protrusion part in a hole type | mold constant, and showed the relationship between the wedge height X and the wedge width Y. In addition, in FIG. 14, in the case of the projection part of the conventional taper shape (conventional shape) and the case of the projection part after improvement (after-improvement shape) are shown in figure for description.

  As shown in FIG. 14, for example, when the wedge height X is 400 mm, the wedge width Y is about 220 mm in the conventional shape, but can be reduced to about 150 mm in the improved shape. As a result, it is apparent that the relief portion is provided in the entire region where the wedge height exceeds 200 mm, and the rolling stability is achieved as described in the above embodiment. At the same time, in the region where the wedge height exceeds 200 mm, the bending stress generated in the projection becomes substantially constant regardless of the wedge height.

  In the above-mentioned embodiment, its modification, etc., although a slab was illustrated and explained as a raw material at the time of manufacturing H section steel, the present invention is naturally applicable also to other materials of similar shape.

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

1 ... rolling equipment 2 ... heating furnace 3 ... sizing mill 4 ... rough rolling machine 5 ... intermediate universal rolling machine 8 ... finishing universal rolling machine 9 ... edger rolling machine 11 ... slab 13 ... H-shaped rough section 14 ... intermediate material 16 ... H-shaped steel product 20 ... upper hole type roll (1st hole type)
21 ... Lower hole type roll (first hole type)
25, 26 ... Protrusions (1st hole type)
28, 29 ... Interruption (1st hole type)
30 ... Upper hole type roll (No. 2-1 hole type)
31 ... Lower hole type roll (No. 2-1 hole type)
35, 36 ····· Protrusions (2−1 hole type)
38, 39 ... Interruption (No. 2-1 hole type)
40 ... Upper hole type roll (2nd 2-hole type)
41 ··· Lower hole type roll (2nd 2-hole type)
45, 46 ... Protrusion (2nd-2 hole type)
45 ', 46' ... (improved) projection 45a, 46a ... tip 45b, 46b ... root 48, 49 ... interrupt (2-2 hole type)
50 ... Upper hole type roll (3rd hole type)
51 ··· Lower hole type roll (3rd hole type)
55, 56 ... Protrusions (third hole type)
58, 59 ... Interruption (3rd hole type)
60 ... Upper hole type roll (4th hole type)
61 ··· Lower hole type roll (4th hole type)
65, 66 ... projection (fourth hole type)
68, 69 ... Interruption (4th hole type)
80 ... flange portion 82 ... web portion 85 ... upper hole type roll (fifth hole type)
86: Lower hole type roll (fifth hole type)
DESCRIPTION OF SYMBOLS 90 ... Relief part 120 ... (Buck-hole type shape) interruption hole type 122, 123 ... Hole side K1 ... 1st hole type K2-1 ... 2nd-1 hole type K 2-2 ... 2nd-2 hole type K3 ... 3rd hole type K4 ... 4th hole type K5 ... 5th hole type (flat shaped hole type)
T: Production line A: Rolled material

Claims (5)

A method of manufacturing an H-shaped steel comprising a rough rolling process, an intermediate rolling process, and a finish rolling process, comprising:
In a rolling mill for performing the rough rolling process on a rectangular cross-section material, a plurality of hole molds for forming a material to be rolled are engraved.
In the plurality of hole molds, one or more pass shaping is performed on the material to be rolled,
The plurality of hole types is a grooved hole type in which an interrupt is formed at the upper and lower end portions in the width direction of the material to be rolled;
One or a plurality of interrupting hole molds in which projections are formed to interrupt the vertical direction in the width direction of the material to be rolled to form divided portions at the end of the material to be rolled,
And a plurality of bending hole types in which projections are formed in contact with the interruptions to sequentially bend divided portions formed in the interruption hole types,
Among the projections formed in the interruption hole type, a part or all of the projections consist of a tip and a root with a predetermined height,
The tip portion is in contact with the material to be rolled when forming the divided portion, and the root portion is configured not to be in contact with the material to be rolled when forming the divided portion. H-shaped steel manufacturing method. The method for manufacturing an H-shaped steel according to claim 1, wherein the shape of the root portion in the rolled cross section is a shape having a substantially constant thickness in the vertical direction. In an interruption hole type provided with a projection consisting of the tip and the root,
When the tip angle of the tip is 30 ° or more and less than 50 °, the tip curvature of the tip is 10 mm or more and 30 mm or less, and the thickness of the rectangular cross-sectional material is 250 mm or more and 300 mm or less, the following formula ( The manufacturing method of the H-section steel according to claim 1 or 2 characterized by performing rolling shaping so that wedge projection width ratio W decided by 2) may be 68% or less.
W = B1 / T (2)
However, it is B1: The maximum width length of a tip part, T: Thickness of a rectangular section material. The hole type side surface which abuts against the left and right side surfaces of the material to be rolled and which restrains the material to be rolled from the left and right is provided in a part or all of the interrupting hole type. The manufacturing method of the H-section steel as described in any one. The above-mentioned interrupting hole type is provided in plurals,
The plurality of interrupting hole types are composed of two types of interrupting hole types which are different in the depth of interruption to be inserted in the width direction of the material to be rolled,
The projection part formed in the interruption hole type of the latter part among the two kinds of interruption hole types concerned consists of the tip part and root part of predetermined height, It is characterized by the above-mentioned. The manufacturing method of the described H-section steel.

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