JP6458917B1 - Manufacturing method of H-section steel - Google Patents

Abstract

An edging rolling process for rolling and shaping the material to be rolled into a predetermined shape, a ridge production process for rotating the material to be rolled to roll the web part, and forming a raised part at the center of the web part of the material to be rolled, An auxiliary edging rolling process in which the material rolled after one or more passes in the part generating process is rotated again and returned to the final hole shape of the edging rolling process to perform light reduction rolling, and the ridge formed in the protruding part generating process The upper and lower hole-type roll that performs the raised-portion generation step, and has a depression that forms the raised portion at the center of the web portion of the material to be rolled. The roll shape of the upper and lower hole type rolls provided at the center of the roll body length is designed so that the tip of the flange portion of the material to be rolled is non-contact, and the two steps of the raised portion generating step and the auxiliary edging rolling step are Continuous Performed one or more times, the ridges erasing step is carried out after ridges generating step and supplemental edging rolling process has been performed.

Description

(Cross-reference of related applications)
This application claims priority based on Japanese Patent Application No. 2017-102423 for which it applied to Japan on May 24, 2017, 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.

  When manufacturing H-section steel, raw materials such as slabs and blooms extracted from a heating furnace are formed into a rough shape (so-called dogbone-shaped material to be rolled) by a roughing mill (BD), and intermediate universal rolling is performed. The thickness of the rough profile web and flange is reduced by a machine, and the edge reduction mill near the intermediate universal rolling mill is subjected to width reduction and forging and shaping of the flange of the material to be rolled. . 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 interrupt is widened in the second and subsequent hole types, or the interrupt depth is increased, and the interrupt on the slab end face is erased in the subsequent hole types.

Moreover, in the manufacture of H-section steel, after so-called edging rolling for edging an end face (slab end face) of a material such as a slab, the flat material is formed by rotating the material to be rolled by 90 ° or 270 ° to reduce the web equivalent part. It is known to perform rolling. In this flat forming rolling, the web equivalent portion is reduced and the flange equivalent portion is reduced and shaped.
By the way, in recent years, larger H-section steel products have been demanded. Therefore, it has been studied to manufacture H-shaped steel products from a slab material having a larger size than before. Here, in general flat forming rolling, when a large material is used as a material to be rolled, various problems such as elongation in the web height direction and deformation of the flange-corresponding portion may occur. There were cases where it was required. Specifically, as the web equivalent portion is reduced, the web equivalent portion is stretched in the longitudinal direction, and the flange equivalent portion is also stretched in the longitudinal direction by being pulled by the stretching, so that the thickness of the flange equivalent portion is reduced. The phenomenon was a concern.

  Regarding such flat shaping rolling, for example, in Patent Document 1, a groove is formed at the center of a flat shaping hole mold, and an unpressed lower portion is provided at the center of the web-corresponding portion during rolling to reduce the length of the cropping portion. Technology is disclosed. This Patent Document 1 describes that edging rolling is performed in a state in which a convex portion (corresponding to a raised portion of the present invention) is formed at the center of the web equivalent portion. Increased efficiency.

  Further, for example, Patent Document 2 discloses a tenter rolling method for advantageously shaping a rough shaped steel slab in the manufacturing process of the shaped steel. Specifically, in Patent Document 2, local rolling is performed on the web equivalent part, then rolling is performed to flatten and widen the central convex part of the web equivalent part, and then the material to be rolled is set up. A rolling method for performing edging rolling is disclosed. According to this method, the flange width, web thickness, and web height can be adjusted to produce various types of rough steel slabs.

JP 59-35802 JP 57-146405 A

  As described above, in recent years, production of large H-shaped steel products has been desired with the increase in size of structures and the like. 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.

  In the manufacture of H-section steel products, conventionally, in order to prevent biting at the flange outer surface position during flat forming rolling, it is known that the material to be rolled is put back into the edging hole mold after flat forming rolling and light rolling is performed. It has been. This light rolling can be said to be so-called auxiliary edging rolling. This is referred to herein as “supplemental edging rolling” or simply “supplemental edging rolling”. In this auxiliary edging rolling, after the web thickness reduction and the flange width direction reduction are performed by flat shaping rolling, the rolled material having a reduced flange width is converted into an edging hole mold because the sheet is returned to the edging hole mold. There is concern about deterioration of material permeability and deterioration of the shape of the material to be rolled. The deterioration of the material permeability and the deterioration of the shape of the material to be rolled during the auxiliary edging rolling are more remarkable when the material to be rolled is large, particularly when manufacturing an H-section steel product having a large web height. There is a fear.

  The technique disclosed in Patent Document 1 is a technique for reducing the length of the cropped portion, and does not disclose any technical idea of shaping a material to be rolled having a large flange width. No mention is made of the effect of carrying out the process, the deterioration of the material permeability and the deterioration of the shape of the material to be rolled. Moreover, the convex part formed in the center of the web equivalent part disclosed by the said patent document 2 is formed, and then the rolling which flattens and widens the central convex part of the web equivalent part is performed, and then the material to be rolled is set up. In the technique of performing edging rolling, each time a convex portion is formed at the center of the web-corresponding portion, a process of flattening the convex portion is employed. There is a concern, and in particular, when the “auxiliary edging rolling” is performed a plurality of times, there is a problem that the increase in the number of times of perforation movement becomes remarkable and the rolling efficiency is lowered.

  In view of the above circumstances, the object of the present invention is to provide a material in “auxiliary edging rolling”, in which a rolling material is returned to an edging hole mold after a raised portion is formed on a web in flat shaping rolling, and light rolling is performed. It is an object of the present invention to provide a method for producing an H-section steel capable of suppressing the deterioration of property and the deterioration of the shape of the material to be rolled and stabilizing the auxiliary edging rolling.

  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 step, an intermediate rolling step, and a finish rolling step, wherein the rough rolling step is performed by applying a predetermined material to be rolled. An edging rolling process for rolling and shaping into a dogbone shape, and a rolled material after the edging rolling process is rotated by 90 ° or 270 ° to roll the web portion, and a raised portion is formed at the center of the web portion of the rolled material. , A ridge generation process, and a material rolled by one or more passes in the ridge generation process is rotated 90 ° or 270 ° again and returned to the final hole shape of the edging rolling process to perform light rolling An edging rolling process and a raised part erasing process for rolling down and eliminating the raised part formed in the raised part generating process. A recess for forming a raised portion at the center of the groove is provided at the center of the roll body length of the upper and lower hole-type roll, and the roll shape of the upper and lower hole-type roll is such that the flange portion tip of the material to be rolled is non-contact The ridge generation process and the auxiliary edging rolling process are continuously performed one or more times, and the ridge elimination process is performed by the ridge generation process and the auxiliary edging rolling process. A method for producing an H-section steel is provided, which is performed after being broken.

  In the auxiliary edging rolling process, light rolling may be performed so that the end of the flange portion of the material to be rolled fills the hole mold in the final hole mold of the edging rolling process.

  In the auxiliary edging rolling step, the web height of the material to be rolled becomes smaller than the web height of the material to be rolled supplied to the hole mold that performs the raised portion generating step immediately before the auxiliary edging rolling step. Alternatively, light rolling may be performed.

  The auxiliary edging rolling step may be performed by one or two chances when one set of a plurality of passes with a constant edging height of the final pass is regarded as one chance.

  The width of the raised portion formed in the raised portion generating step may be set to 25% or more and 50% or less of the in-web method of the material to be rolled.

  According to the present invention, in the “auxiliary edging rolling” in which the material to be rolled is put back into the edging hole mold and the light rolling is performed after forming the raised portion on the web in the flat shaping rolling, in the “auxiliary edging rolling”, the material permeability is deteriorated or the material is covered. It is possible to suppress the deterioration of the rolled material shape and stabilize auxiliary edging rolling.

It is a schematic explanatory drawing about the production line of H-section steel. It is a schematic explanatory drawing of a 1st flat modeling hole type | mold. It is a schematic explanatory drawing of a 2nd flat modeling hole type | mold. It is the schematic of the last hole type | mold of the edging rolling process of the rough rolling process in manufacture of H-section steel. It is a schematic explanatory drawing regarding the auxiliary edging rolling between an edging last hole type | mold and a general flat shaping | molding hole type | mold. It is a schematic explanatory drawing of the auxiliary edging rolling which concerns on this Embodiment. It is a graph which shows transition of the flange width | variety of the to-be-rolled material A for every path | pass when multiple pass | pass passes at the time of flat shaping rolling. It shows the transition of the flange width when the H-shaped rough shaped material is modeled by rolling modeling in a total of 18 passes using the first flat modeling hole mold, the second flat modeling hole mold, and the three widened hole molds in the subsequent stage. It is a graph. It is a graph which shows the relationship between a relief rate and the flange width increase / decrease after H-shaped rough shape shaping based on the data of FIG.

  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.

(Outline of production line)
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 (subsequently rolled material A) that is, 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. Usually, the rolls of the sizing mill 3 and the roughing mill 4 are engraved with a so-called flat shaping hole mold that reduces the thickness of the edging hole mold and the web part and forms the shape of the flange part. The H-shaped rough profile 13 is formed by reverse rolling of a plurality of passes through the sizing mill 3 and the rough rolling mill 4. The H-shaped rough shaped material 13 is subjected to a plurality of passes of rolling by using a rolling mill row composed of two rolling mills, the intermediate universal rolling mill 5 and the edger rolling mill 9, 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 of the slab 11 extracted from the heating furnace 2 is in the range of 290 mm or more and 310 mm or less, for example. This is a dimension of a slab material called a so-called 300-thick slab used when manufacturing a large H-shaped steel product.

In the sizing mill 3 and the roughing mill 4 shown in FIG. 1, an edging rolling process is first performed as a preceding process. In the edging rolling process, rolling modeling is performed in a state where a rectangular cross-section material (slab 11) is erected, and modeling is performed so as to have a predetermined substantially dog-bone shape.
Following the edging rolling process, the flat shaping rolling process is performed as a subsequent process. In the flat shaping rolling process, first, the material A to be rolled that has undergone the edging rolling process is rotated by 90 ° or 270 °. With this rotation, the flange portions located at the upper and lower ends of the material A (slab 11) in the edging rolling process are arranged so as to come on the rolling pitch line. Next, the web part which is a connection part which connects two flange parts is reduced. The H-shaped rough profile 13 shown in FIG. 1 is modeled by these edging rolling process and flat modeling rolling process.

  In general, the preceding process and the subsequent process are collectively referred to as a rough rolling process. In the method for manufacturing the H-section steel according to the present embodiment, the edging rolling process, which is the preceding process, of the rough rolling process may be performed by a conventionally known general method. Therefore, in this specification, detailed description of the edging rolling process is omitted. Below, with reference to drawings, the flat shaping rolling process which is a latter process is demonstrated in detail.

(Outline of hole type configuration)
2 and 3 are schematic explanatory views of the first flat shaping hole mold KH1 and the second flat shaping hole mold KH2 used in the flat shaping rolling process. The first flat shaping hole mold KH1 includes a pair of horizontal rolls, an upper hole roll 85 and a lower hole roll 86. As shown in FIG. 2, in the first flat shaping hole mold KH1, the material A to be rolled formed in the edging rolling process is rotated 90 ° or 270 °, and the upper and lower ends of the material A to be rolled until the preceding step. The flange portion 80 located at is located so as to be on the rolling pitch line. And in the 1st plane shaping hole type | mold KH1, the web part 82 which is a connection part which connects the two flange parts 80 is reduced.

  Here, the upper and lower hole type rolls 85 and 86 of the first flat shaping hole type KH1 have a shape in which recesses 85a and 86a having a predetermined length L1 are formed in the center part of the roll body length. Due to the hole-type configuration shown in FIG. 2, the web portion 82 is partially reduced. As a result, the web portion 82 after the reduction is formed with a reduction portion 82a at both ends in the web height direction and a raised portion 82b as an uncompressed portion at the center. In this way, rolling modeling is performed in which a raised portion 82b is formed on the web portion 82 in a so-called dogbone-shaped material to be rolled. In the present specification, the step of forming the raised portion 82b on the web portion 82 in the first flat shaping hole mold KH1 is also referred to as “the raised portion generating step”.

  In the first flat shaping hole mold KH1, rolling shaping is performed such that the web portion 82 is partially crushed and the raised portion 82b is formed. Is also called. The width of the raised portion 82b after the formation is the same as the width L1 of the recessed portions 85a and 86a. Here, as shown in the enlarged view of FIG. 2, the width L1 of the recesses 85a and 86a in this specification is a width at a depth that is ½ of the depth hm of the recesses 85a and 86a. It is prescribed as A later-described escape amount L1 is also based on the same rule.

  FIG. 3 is a schematic explanatory view of the second flat shaping hole mold KH2. The second flat shaping hole mold KH2 includes a pair of horizontal rolls, an upper hole roll 95 and a lower hole roll 96. In the second flat shaping hole mold KH2, the raised portion 82b formed in the web portion 82 is erased from the material A rolled and shaped in the first flat shaping hole mold KH1, and the inside of the web portion 82 Rolling modeling is performed to widen the method.

  In the second flat shaping hole mold KH2, rolling is performed in which the upper and lower hole mold rolls 95 and 96 are brought into contact with the raised portion 82b formed in the web portion 82 to reduce (erase) the raised portion 82b. Along with the reduction of the raised portion 82b, the spread in the web height direction and the metal flow to the flange portion 80 are promoted. By such a metal flow, it becomes possible to carry out rolling shaping without causing flange surface reduction as much as possible. In this specification, the step of reducing (erasing) the raised portion 82b in the second flat shaping hole mold KH2 is also referred to as a “raised portion erasing step”. The second flat shaping hole mold KH2 is also referred to as a “protruding part erasing hole type” because it erases the protruding part 82b formed in the web part 82.

  Regarding the rolling shaping in the first flat shaping hole mold KH1 and the second flat shaping hole mold KH2, the detailed conditions and the like (hole shape dimensions, etc.) are based on the knowledge obtained by the present inventors. This will be described later in more detail in the description of the embodiment.

  A rolling mill row consisting of two rolling mills, an intermediate universal rolling mill 5-an edger rolling mill 9, for the H-shaped rough profile 13 shaped through the first flat shaping hole mold KH 1 and the second flat shaping hole mold KH 2. The intermediate material 14 is shaped by applying a plurality of passes of reverse rolling. 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).

  In the rough rolling process in the manufacture of the H-section steel, as described above, after performing the edging rolling process and the flat shaping rolling process, after reducing the thickness of the web portion, the material to be rolled again into the edging hole mold again. It is known to perform “auxiliary edging rolling” in order to put back A and prevent biting from the outer surface position of the rolled material flange portion in the flat shaping hole mold. This “auxiliary edging rolling” is a technique that has been conventionally performed for the purpose of shaping the unsteady portion of the material to be rolled and suppressing shape defects such as biting.

(Previous auxiliary edging rolling)
First, the conventional auxiliary edging rolling will be briefly described with reference to FIGS. FIG. 4 is a schematic diagram of the final hole type KE (hereinafter also referred to as the edging final hole type KE) of the edging rolling process of the rough rolling process in the manufacture of H-section steel. As shown in FIG. 4, the edging final hole type KE is engraved in an upper hole type roll 50 and a lower hole type roll 51 which are a pair of horizontal rolls. On the peripheral surface of the upper hole type roll 50 (that is, the upper surface of the hole mold), 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 (that is, the hole bottom surface) of the lower hole roll 51. 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.

  As shown in FIG. 4, in the edging final hole mold KE, the rolled material A is reduced in the web width direction with the material A to be rolled up and the flange is widened. Specifically, the outer surface of the flange portion 80 (upper and lower end surfaces of the material to be rolled A) is pressed down by the upper and lower hole-type rolls 50 and 51 in which the protrusions 55 and 56 are formed.

  In the conventional H-shaped steel manufacturing technology, the material A to be rolled that has passed through the edging final hole mold KE shown in FIG. 4 is introduced into a general flat shaped hole mold, and the thickness of the web portion is reduced. FIG. 5 is a schematic explanatory diagram regarding auxiliary edging rolling between the edging final hole mold KE and a general flat shaping hole mold GH, in which (a) is before the auxiliary edging rolling, and (b) is auxiliary. The time of edging rolling is shown. As shown in FIG. 5A, in a general flat shaping hole mold GH, the web part of the material A to be rolled is reduced simultaneously with the reduction of the flange part 80 in the width direction. Therefore, as shown in FIG. 5B, the width of the flange portion 80 is considerably shortened. As a result, the material A to be rolled having the flange portion 80 with a short width is returned to the edging final hole mold KE for auxiliary edging rolling.

  As shown in FIG. 5B, when the material A to be rolled having the flange portion 80 having a short width is reintroduced into the edging final hole mold KE, the flange 80 is not formed in the edging final hole mold KE. It will be in the state of fullness (refer the broken line enclosure part in Drawing 5 (b)). Unfilled flange portion 80 in such a hole mold is likely to cause phenomena such as poor lateral centering properties during rolling, web buckling, imperfect dimensions such as imbalance in the left and right thickness of flange portion 80, and poor shape. Was a problem.

(Auxiliary edging rolling according to this embodiment)
On the other hand, in the present embodiment, the flat shaping hole mold used at the time of auxiliary edging rolling is a “web partial rolling hole mold” which is the first flat shaping hole mold KH1 shown in FIG. In addition to this, an appropriate condition is defined such that the shrinkage of the flange portion 80 in the rolling shaping by the web partial rolling hole die is minimized. Thereby, when the material A to be rolled is reintroduced into the edging final hole mold KE, the hole mold is not filled. 6A and 6B are schematic explanatory diagrams of auxiliary edging rolling according to the present embodiment, in which FIG. 6A shows before auxiliary edging rolling and FIG. 6B shows the time when auxiliary edging rolling is executed.

  As shown in FIG. 6, in the first flat shaping hole mold KH1 according to the present embodiment, a raised portion 82b is generated when the web is thinned. Thereby, the pull-down of the flange part 80 is hard to occur, and the reduction rate of the flange width becomes low. Therefore, as shown in FIG. 6B, the width of the flange portion 80 is hardly reduced. Since the change in the flange width is small, it is returned to the edging final hole mold KE, and the restraining force of the hole sidewall when the auxiliary edging rolling is performed is also maintained. For this reason, left-right centering property is favorable, and dimensional defects and shape defects such as web buckling and left-right thickness unbalance of the flange portion 80 are suppressed. In the first pass of the first flat shaping hole mold KH1, the shape of the flange portion 80 is not in contact with the hole mold during rolling shaping, and the flat shaping rolling before auxiliary edging rolling (ie, It is desirable to design the roll so that the flange tip is in contact with the roll hole mold in the raised portion generation step). By carrying out the auxiliary edging rolling under such conditions, the hole fillability when the material to be rolled A is returned to the edging final hole mold KE is improved, and the rolling stability is improved.

At the time of auxiliary edging rolling, for example, edging rolling of about 40 mm or less is preferably performed, and in this case, the flange width expansion amount is about 24 mm or less.
By the way, at the time of flat shaping rolling, the web height of the material A to be rolled is made as small as possible with respect to the hole width W of the “web partial rolling hole mold” which is the first flat shaping hole mold KH1 (see FIG. 2). Thereby, the distance between the outer surface of the flange part 80 and a hole-type roll outer wall can be enlarged. Thereby, it is possible to carry out rolling with a margin against the slack by the perforated roll outer wall with respect to the spread of the material A to be rolled in the web height direction accompanying the web reduction during flat shaping rolling. From such a viewpoint, it is desirable that the edging amount during auxiliary edging rolling be as large as possible.

  On the other hand, in order to improve the rolling stability in flat modeling rolling, it is required to increase the hole-type restraining force of the material A to be rolled. With respect to the hole-type restraining force, the inductivity decreases as the distance between the outer wall of the flat-shaped hole-type hole roll and the material A to be rolled increases and as the amount of widening in the web inner method increases. Rolling becomes unstable. From the viewpoint of such material permeability, it is desirable that the amount of edging during auxiliary edging rolling be as small as possible.

  For the reasons described above, the optimum value of the edging amount during auxiliary edging rolling should be determined in consideration of the balance between wrinkle generation and rolling stability. When flat shaping rolling is performed after completion of the auxiliary edging rolling, it is desirable that the side wall (outer wall) of the flat shaping hole mold and the web height of the material A to be rolled are substantially matched.

  Here, rolling of the web part 82 is regarded as plate rolling. The sheet width ratio is about 3 to 4 and the sheet thickness ratio is about 4 to 5 from the dimensional relationship between the roll diameter of a normal shape rolling mill and the rolled material of the large H-section steel. Furthermore, since the flange portions are provided at both ends of the plate thickness, the amount of expansion is further increased. As a result, the spread ratio in the web height direction of the material A to be rolled due to the web reduction is 4% or more of the web height. That is, when considering the material A to be rolled having a web height dimension of 1000 mm, for example, as a large H-shaped steel, the spread ratio of the web height is at least 40 mm. Therefore, as a condition not to contact the outer wall of the perforated roll of the flat shaping hole type, from the viewpoint of material permeability, etc., by performing an edging amount of 40 mm or more, which is equal to or larger than the spread amount of the web height during flat rolling, during auxiliary edging rolling With respect to the roll forming side of the flat shaping rolling, it comes into contact with the perforated side wall and does not impair the material permeability. That is, the amount of edging during auxiliary edging rolling is preferably 40 mm or less.

  Moreover, about the flange width expansion accompanying edging rolling, the width expansion rolling characteristic by slab edging can be applied. That is, the flange width expansion characteristic by the conventional slab edging method by the hole type having a protrusion at the center of the so-called box hole type is applied. In this case, since it is known that at least about 60% or less of the reduction amount is the flange width expansion, 40 mm × 0.6 (60%) = 24 mm is calculated.

FIG. 7 is a graph showing the transition of the flange width of the material A to be rolled for each pass when a plurality of passes have passed during flat shaping rolling. In addition, the example of FIG. 7 is data when FEM calculation is performed using a 2000 mm × 300 mm cross-section slab as a material. In FIG. 7, flat shaping rolling with a conventional general shaping hole mold GH (hereinafter referred to as “conventional method”) and flat shaping rolling with the first flat shaping hole mold KH1 according to the present embodiment ( (Hereinafter referred to as “the method of the present invention”).
As shown in FIG. 7, the reduction rate of the flange width by the flat shaping rolling according to the present embodiment was smaller than the reduction rate of the flange width by the conventional method. For example, after 13 passes of flat shaping rolling, the difference in flange width by each flat shaping rolling was 100 mm or more. From the result of FIG. 7, in flat shaping rolling by the first flat shaping hole mold KH <b> 1 according to the present embodiment, the reduction rate of the flange width becomes low, and the hole mold unfilled during auxiliary edging rolling is suppressed. Can understand.

  The present inventors also confirmed through experiments that the material permeability differs depending on the fillability of the hole mold at the time of auxiliary edging rolling, and that there is a problem in the material permeability when the hole mold is not filled. . Table 1 shown below is an experimental example showing the relationship between the hole filling property and the material passing property in auxiliary edging rolling. Table 1 shows the relationship between the hole filling property and the material permeability in the conventional method and the method of the present invention under the conditions of Case 1 to Case 4. At the time of auxiliary edging rolling, edging rolling with an edging amount of about 40 mm was performed in two passes in all cases 1 to 4. Therefore, the value of the web height change at the time of auxiliary edging rolling shown in Table 1 is expressed as −40 mm in all cases 1 to 4.

  As shown in Table 1, when the hole mold was filled during auxiliary edging rolling, the material permeability was good. On the other hand, when the hole mold was not full, bending occurred. Further, referring to cases 2 to 4, in the conventional method and the method of the present invention, when the same cumulative web reduction amount is taken at the time of auxiliary edging rolling, the cumulative web reduction amount that is not filled with the hole type in the conventional method. Even so, in the method of the present invention, the hole mold was filled, and the material permeability was sometimes kept good (see cases 2 and 3 in Table 1). In addition, since the edging rolling of about 40 mm was performed at the time of auxiliary edging rolling, the value of the web height at the time of auxiliary edging rolling shown in Table 1 is -40 mm in all cases 1 to 4.

  Next, the present inventors considered that the effect of suppressing dimensional defects and shape defects differed depending on the schedule design (rolling amount, pass schedule, etc.) of auxiliary edging rolling according to the present embodiment. Then, the transition of the flange width by auxiliary edging rolling in the case of manufacturing H-section steel using a 2000 mm × 300 mm cross-section slab as a raw material was verified by experiments.

Table 2 shown below shows the transition of the flange width for each pass when flat modeling rolling is performed using the first flat modeling hole mold KH1 (that is, the web partial rolling hole mold). Cases 1 to 3 in Table 2 differ in the number of times of auxiliary edging rolling for each pass of flat shaping rolling. When the auxiliary edging rolling is performed (that is, the case 2 and the case 3), the transition of the flange width after the auxiliary edging rolling is shown. In addition, the description of the 15th pass to the 23rd pass in the table indicates that edging rolling was performed in the previous stage as the 1st to 14th passes before the flat shaping rolling, and the 15th pass and thereafter It shows that it is flat forming rolling.
At the time of auxiliary edging rolling, edging rolling of about 40 mm was performed. Specifically, in case 2, edging rolling of about 40 mm was performed once in two passes. In Case 3, edging rolling of about 20 mm was performed twice in two passes. As shown in Table 2, the amount of flange width expansion by auxiliary edging rolling was about 24 mm in any pass in case 2 and about 44 mm in any pass in case 3.

なお、表２中の「ケース２：補助的エッジング圧延１回」、「ケース３：補助的エッジング圧延２回」との記載は、２パスを１組として実施される補助的エッジング圧延の回数を示しており、この２パスを１組とした補助的エッジング圧延回数の表記は「１チャンス」、「２チャンス」とも表記される。実際には、１チャンスでの補助的エッジング圧延パス回数は１パスでも良いし、２パス以上の複数であっても構わないが、トータルのエッジング量は一定の条件（即ち、最終パスのエッジング高さを一定とする条件）としてパスケジュールが設計される。
また、表２には、参考のためケース１として補助的エッジング圧延無しで平造形圧延を行った場合の各パスでのフランジ幅推移を載せている。

In Table 2, “Case 2: Auxiliary edging rolling once” and “Case 3: Auxiliary edging rolling 2 times” indicate the number of times of auxiliary edging rolling carried out with two passes as one set. The number of auxiliary edging rollings with the two passes as one set is also expressed as “1 chance” and “2 chance”. Actually, the number of auxiliary edging rolling passes in one chance may be one pass or a plurality of two or more passes, but the total edging amount is constant (that is, the edging height of the final pass). Paschedule is designed as a condition that keeps constant.
Table 2 lists the transition of the flange width in each pass when the flat shaping rolling is performed without auxiliary edging rolling as case 1 for reference.

Case 2 in Table 2 shows the flange width after performing auxiliary edging rolling in each pass shown in Case 1 for 1 chance in each pass under conditions that do not restrict the expansion of the flange width.
As shown in Case 2 in Table 2, when auxiliary edging rolling is performed in one chance, the flange width after auxiliary edging rolling in the 15th to 17th passes is the edging hole mold width before flat shaping rolling (1010 mm). ). Therefore, hole filling is realized in the edging final hole mold KE during auxiliary edging rolling. In Table 2, “◯” indicates that hole-type filling is realized and rolling stability is good.
On the other hand, since the flange width after the auxiliary edging rolling is less than the edging hole mold width (1010 mm) before the flat shaping rolling for the 18th pass and after, the edging final hole mold KE is not filled during the auxiliary edging rolling, There is a risk of dimensional defects and shape defects. What is described as “x” in Table 2 indicates that there is a problem in rolling stability because the hole type is not filled.

In addition, as shown in Case 3 of Table 2, the present inventors also verified the case where auxiliary edging rolling was performed in two chances (in the table: auxiliary edging rolling twice). In this case 3, after the 18th pass, which was not filled with the hole in case 2, the number of auxiliary edging rolls was increased and the auxiliary edging rolling was performed under the condition that the expansion of the flange width was not restricted in two chances. The flange width is shown.
When the auxiliary edging rolling is performed in 2 chances, the flange width at the time of auxiliary edging rolling can be expected to be larger than that in the case of 1 chance. Mold filling becomes feasible. Under this verification condition, as shown in Table 2, hole filling is realized in the edging final hole mold KE during auxiliary edging rolling up to the 22nd pass.
In general, it is desired that the auxiliary edging rolling is stably performed in a later stage of the flat shaping rolling. This is because, as auxiliary edging rolling is performed in the latter pass of flat shaping rolling, the dimensional accuracy of the shape of the material to be sent to the subsequent intermediate rolling and finishing rolling is improved, and the rolling stability and product dimensional accuracy are improved. This is because the improvement is achieved.
That is, by performing auxiliary edging rolling in two chances, auxiliary edging rolling at a later stage can be realized without causing dimensional defects and shape defects of the material to be rolled, and the efficiency of rolling can be improved. Recognize.

  For reference, Table 3 below shows the transition of flange width after flat molding rolling in the conventional method (case 1), and the flange width at the time of auxiliary edging rolling after auxiliary edging rolling after each pass. This shows the transition of the flange width in consideration of the expansion (Case 2). As shown in Table 3, in the conventional method, the flange width after auxiliary edging rolling exceeds the edging hole mold width (1010 mm) before flat shaping rolling only in the fifteenth pass, and the edging final hole during auxiliary edging rolling. Hole filling is realized in the mold KE. On the other hand, after the 16th pass, since the flange width after the auxiliary edging rolling is less than the flange width (1010 mm) before the flat shaping rolling, the edging final hole KE is not filled at the time of the auxiliary edging rolling, and the dimension is poor. , There is a risk of shape failure.

  As can be seen by comparing Table 2 and Table 3, when the method of the present invention is applied, when the auxiliary edging rolling is performed in only one chance, the auxiliary edging rolling that realizes the hole filling up to the 17th pass is performed. It was possible. In the case where the auxiliary edging rolling is performed in two chances, the auxiliary edging rolling in which the hole-type filling is realized up to the 22nd pass can be performed. On the other hand, in the conventional method, auxiliary edging rolling in which hole-type filling was realized only up to the 15th pass could be performed. That is, by applying the method of the present invention, it is possible to perform auxiliary edging rolling in a later pass, suppress dimensional defects and shape defects such as wrinkles, and perform a rough rolling process with high accuracy. .

(Ratio of escape amount (bump formation width) in the first flat shaping hole mold KH1)
As described above, the raised portion 82b is formed at the center of the web portion 82 of the material A to be rolled in the first flat shaping hole mold KH1 (see FIG. 2 and the like) according to the present embodiment. The formed raised portion 82b is erased in the second flat shaping hole mold KH2 at the subsequent stage. Then, after the bulging portion is erased, widening rolling by the in-web method is performed as necessary, and an H-shaped rough shaped material is formed.

The inventors of the present invention have the width L1 of the raised portion 82b formed in the first flat shaping hole mold KH1 (that is, the escape amount of the in-web method in the rolling shaping with the first flat shaping hole mold KH1. It has been found that the flange width of the finally obtained H-shaped rough shape is changed by simply changing the amount of escape. This means that as the width L1 of the raised portion 82b is increased, the flange thickness is easily secured, while the flange width is reduced by the longitudinal stretching action of the material A to be rolled at the time of the subsequent removal of the raised portion. caused by.
Then, the present inventors verified the relationship between the escape amount of the in-web method in the rolling modeling with the first flat shaping hole mold KH1 and the flange width of the H-shaped rough material finally obtained.

FIG. 8 shows an H-shaped rough shape obtained by rolling modeling in a total of 18 passes using the first flat shaping hole mold KH1, the second flat shaping hole mold KH2, and further three widening hole molds in the subsequent stage. It is a graph which shows transition of the flange width for every pass at the time of shaping a shape material. FIG. 8 shows data using a material slab having a width of about 2000 mm.
Moreover, although the horizontal axis in the graph of FIG. 8 is 1 to 18 paths, 1 to 13 paths thereof correspond to the first flat shaping hole mold KH1, and 14 and 15 paths correspond to the second flat shaping hole mold KH2. , 16 to 18 passes correspond to the hole form of widening rolling.

Further, FIG. 8 shows respective data when the escape amount L1 is changed. In FIG. 8, the value shown in the following formula (1) is defined as the escape rate, and when the escape rate is 12%, 17%, 23%, 28%, 33%, 39%, 44%, 49% Data is described, and the case where the escape rate is 0% is described as the conventional method.
Escape rate [%] = (Escape amount L1 / In-web method L2) × 100 (1)

  By increasing the escape rate, the amount of shrinkage at the flange portion 80 in the first flat shaping mold KH1 (the amount of decrease in the flange thickness) is reduced. Therefore, as shown in FIG. 8, the flange width of the finally obtained H-shaped rough shape tends to increase as the escape rate increases. This tendency was also confirmed by experiments as shown in FIG. However, the flange width after the erasure of the raised portion and the widening rolling in the second flat shaping hole mold KH2 was not necessarily increased even if the escape rate was increased to a predetermined value or more. This is presumed to be caused by the fact that the flange shrinkage amount is increased at the time of erasure of the raised portion in the second flat shaping hole mold KH2 when the escape portion is enlarged.

  That is, when a method for forming the raised portion 82b described in the present embodiment is adopted as a manufacturing process of the large H-section steel, it is considered that there is a suitable range for the escape rate. It is done. Therefore, the present inventors have focused on the relationship between the escape rate and the increase / decrease in the flange width after forming the H-shaped rough shape material, and derived a suitable numerical range of the escape rate.

  FIG. 9 is a graph showing the relationship between the escape rate and the flange width increase / decrease rate after forming the H-shaped rough profile based on the data of FIG. Note that the flange width increase / decrease rate in FIG. 9 is the flange width when the escape rate is each value (12% to 55%) with the flange width when the escape rate is 0% as a reference (1.000). It is the value which showed.

As shown in FIG. 9, in the region where the escape rate is small, the flange width of the H-shaped rough profile tends to increase as the escape rate increases. However, the flange width increase / decrease rate was substantially constant in the region where the relief rate was about 25% or more and about 50% or less (see the broken line portion in FIG. 9).
From the results shown in FIG. 9, in the case of producing a large H-shaped steel product having a larger flange width than in the prior art, in view of the fact that rolling shaping is desired so that the flange width of the H-shaped rough profile is also increased, the relief is required. It can be seen that the numerical range of the rate is preferably 25% to 50%. Further, in the rolling shaping process, from the viewpoint of preventing an increase in rolling load and increasing production efficiency, the escape rate is preferably as low as possible. Therefore, it is desirable to set the escape rate to about 25%. .

(Function and effect)
According to the manufacturing method of the H-section steel according to the present embodiment described above, the first flat shaping hole mold KH1 for forming the raised portion 82b is formed by the flat shaping rolling performed after the edging rolling. ing. As a result, in the “auxiliary edging rolling” in which the rolled material A is put back into the edging final hole mold KE after the flat shaping rolling and the light rolling is performed, the deterioration of the material permeability and the rolled material shape are suppressed. It is possible to stabilize the auxiliary edging rolling. Moreover, it becomes possible to roll-form the H-shaped rough shaped member 13 having a larger flange width than before, and as a result, it becomes possible to produce an H-shaped steel product having a larger flange width than before.

  For example, when performing rolling modeling of the H-shaped rough profile according to the present embodiment on the basis of a material having a thickness of about 300 mm and a width of about 2000 mm, which is called a 300-thick slab, When using the first flat shaping hole mold KH1 which is a “hole type”, the relief rate is set in the range of 25% to 50% (more preferably about 25%) in the formation of the raised portion 82b, and the rolling shaping is performed. It is possible to maximize the flange width of the H-shaped rough shape.

  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.

  For example, in the above-described embodiment, as a stage before performing flat modeling rolling using the first flat modeling hole mold KH1, it is assumed that a rectangular cross-section material (slab) is subjected to flat modeling rolling after rolling modeling by edging rolling. However, the scope of application of the present technology is not limited to this. That is, the technique of the present invention can also be applied to the case where flat forming rolling is performed on a material to be rolled that has not undergone an edging rolling process such as a beam blank.

  The present invention can be applied to a manufacturing method 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 50 ... Upper hole type roll (edging final hole type)
51. Pre-hole type roll (edging final hole type)
55, 56 ... Protrusion (edging final hole type)
80 ... Flange part 82 ... Web part 82a ... Reduced part 82b ... Raised part (uncompressed part)
85 ... Upper hole type roll (first flat shaping hole type)
85a ... hollow part 86 ... pilot hole type roll (first flat shaping hole type)
86a ... hollow part 95 ... upper hole type roll (second flat shaping hole type)
96 ... lower hole type roll (second flat shaping hole type)
KH1 ... 1st flat shaping hole type KH2 ... 2nd flat shaping hole type KE ... Edging final hole type GH ... General flat shaping hole type T ... Production line A ... Rolled material

Claims (5)

A method for producing an H-section steel comprising a rough rolling process, an intermediate rolling process, and a finish rolling process,
The rough rolling step is an edging rolling step for rolling and shaping the material to be rolled into a predetermined dogbone shape,
A raised portion generating step of rolling the web portion by rotating the rolled material by 90 ° or 270 ° after completion of the edging rolling step and forming a raised portion at the center of the web portion of the rolled material;
An auxiliary edging rolling process in which the material rolled by one or more passes in the ridge generation process is rotated 90 ° or 270 ° again and returned to the final hole shape of the edging rolling process to perform light rolling.
A ridge erasing step that reduces and eliminates the ridge formed in the ridge generation step,
In the up-and-down hole type roll that performs the raised part generation step, a hollow part that forms a raised part in the center of the web part of the material to be rolled is provided in the center of the roll body length of the up-and-down hole type roll,
The roll shape of the upper and lower hole type rolls is designed so that the tip of the flange portion of the material to be rolled is non-contact,
The two steps of the raised portion generating step and the auxiliary edging rolling step are continuously performed one or more times,
The method for producing an H-section steel, wherein the ridge erasure step is performed after the ridge generation step and the auxiliary edging rolling step. In the said auxiliary edging rolling process, light rolling is performed so that the flange part front-end | tip of a to-be-rolled material may fill the said hole type in the last hole type | mold of the said edging rolling process, It is characterized by the above-mentioned. Manufacturing method of H-section steel. In the auxiliary edging rolling step, the web height of the material to be rolled becomes smaller than the web height of the material to be rolled supplied to the hole mold that performs the raised portion generating step immediately before the auxiliary edging rolling step. The method for producing an H-section steel according to claim 2, wherein light rolling is performed. The auxiliary edging rolling step is performed by one or two chances when one set of a plurality of passes with a constant edging height of the final pass is regarded as one chance. The manufacturing method of the H-section steel as described in any one of Claims. The width | variety of the protruding part formed in the said protruding part production | generation process is set to 25% or more and 50% or less of the web inner part method of a to-be-rolled material, It is characterized by the above-mentioned. Of manufacturing H-section steel.

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