JP6536415B2 - H-shaped steel manufacturing method - Google Patents

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, and the above-described intermediate universal rolling mill The thickness of the web and the flange of the rough profile is reduced, and the flange of the material to be rolled is subjected to width reduction and wrought and shaping of the end face by an edger rolling machine adjacent 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, various techniques have been created as a method of forming a so-called dog bone-shaped rough shape from a slab material having a rectangular cross section. For example, according to Patent Document 1, a groove is formed at the end of the material of a rectangular cross-sectional material using an insert projection formed in a roll collar between box-hole types, and a combination of a box-hole type and an insert projection is used. There is disclosed a technique for obtaining a large size rough shaped steel piece (dog bone shaped material).

Further, for example, in Patent Document 2, after the slab end face is interrupted in the first hole type of the rough rolling process, the interruption is divided in the second and subsequent hole types, or the interruption depth is increased to edging. A technique is disclosed for rolling and for eliminating the interruption of the slab end face in the subsequent hole type.

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

  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, in the technology described in Patent Document 1 above, edging rolling is performed immediately on a material such as a slab into which an interrupt has been made, using a box-hole type having a flat bottom surface, without undergoing transition or the like of the interrupt shape. The flange equivalent portion is formed, and in such a method, a shape defect is apt to occur due to the rapid change of the shape of the material to be rolled. 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.

  Further, for example, in the technique disclosed in Patent Document 2 described above, in the method of interrupting the end face (slab end face) of a material such as a slab, edging the end face, and performing rough rolling using its 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.

  In addition, when manufacturing an H-shaped steel product having a wider flange, the rough rolling process and the subsequent rolling process are performed in order to form a material to be rolled having a wider flange width than in the prior art from the shaping in the rough rolling process. There is concern that there are problems with shape defects and the like that have not been present in the past, and there is a demand for the realization of a solution method.

  In view of such circumstances, it is an object of the present invention to interrupt deeply at the end face of a material such as a slab or the like in the rough rolling step using a hole type at the time of manufacturing H-shaped steel with a protrusion having an acute tip shape. By inserting and sequentially bending the flange portion formed thereby, the occurrence of shape defects in the material to be rolled is suppressed, and an H-shaped steel product having a wider flange width than before is efficiently and stably manufactured, and rough An object of the present invention is to provide a manufacturing technique of an H-shaped steel capable of improving the passing property without causing a shape defect in shaping using a flat shaping hole type in a rolling process.

  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, the rolling mill performing the rough rolling process being a workpiece A plurality of five or more hole molds for forming the rolled material are engraved, and one or more pass molding of the material to be rolled is performed in the plurality of hole molds, and the first hole mold and the second of the plurality of hole molds are formed. In the hole type, a projection is formed to insert an interrupt vertically in the width direction of the material to be rolled to form a divided portion at the end of the material to be rolled, and the third of the plurality of hole types except the last hole type From the hole type onwards, there are formed projections which abut the interruptions and sequentially bend the formed divisions, and the last hole type after the third hole type except the last hole type among the plurality of hole types. To form a flat portion in the form of a straight line on the inner side surface of the tip of the divided portion that is folded Are provided at both ends of the protrusion, and the final hole type of the plurality of hole types is a flat modeling hole type, and in rolling and shaping in the flat modeling hole type, at least in the final pass, the tip of the divided portion A method of manufacturing an H-shaped steel is provided, characterized in that the flat portion formed on the inner side surface of the portion is brought into surface contact with the hole side wall of the flat shaped hole type.

  The tip angle of the projection formed in the last hole type after the third hole type after the last hole type among the plurality of hole types may be 130 ° or more and 170 ° or less.

  The rolling formation in the last hole type after the third hole type excluding the last hole type among the plurality of hole types may be performed in a plurality of passes.

  In the rolling and forming with the flat forming hole type, when the ratio I of the flange piece width to the flange thickness is 1.30 or more at the flange portion of the material to be rolled corresponding to the divided portion, the flange of the flange portion The width reduction ratio may be 10% or more.

  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, efficiently and stably manufacture H-shaped steel products having a wider flange width than in the prior art, and flat-patterned holes in the rough rolling process. It is possible to improve the material passing property without causing a shape defect in modeling using a mold.

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 a 2nd hole type | mold. It is a schematic explanatory drawing of a 3rd hole type | mold. It is a schematic explanatory drawing of a 4th hole type | mold. It is a schematic explanatory drawing of the 5th hole type (flat modeling hole type). It is explanatory drawing at the time of implementing shaping including thickness pressure reduction of a web part using the 5th hole type to a material to be rolled after shaping in a 4th hole type. In a 4th hole type | mold, it is a schematic explanatory drawing at the time of improving the shape of the contact surface of a flange part and a hole type | mold roll. It is a schematic explanatory drawing which shows the mode of the rolling shaping | molding in the 5th hole type | mold of the to-be-rolled material in which the flange front end side part was formed. It is a general | schematic enlarged explanatory drawing which shows the rolling shaping | molding of a flange front end side part in detail. It is a graph which shows the relationship between the rolling-reduction | draft ratio of the flange part in a 5th hole type, and the depth of the weir which arises in the outer surface of a flange part after shaping in a 5th hole type.

  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 the 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 reverse rolling of approximately 10 or more passes through these makes the H shape rough. A cross section 13 is formed, and a plurality of passes of reduction are applied to the H-shaped rough section 13 by using a rolling mill train comprising two rolling mills of the intermediate universal rolling mill 5-edger rolling mill 9, and an intermediate material 14 are 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. 2 to 6 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, although the case where five hole types are engraved is described as an example, the number of hole types does not necessarily have to be five hole types, and the number of a plurality of five or more hole types It may be That is, any hole-type configuration suitable for forming the H-shaped rough member 13 may be used. In addition, in FIGS. 2-6, 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. Furthermore, on the circumferential surface of the lower hole type roll 21 (that is, the bottom surface of the first hole type K1), a protrusion 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. Here, it is desirable that a tip end angle (also referred to as a wedge angle) θ1a of the protrusions 25 and 26 be, for example, 25 ° or more and 40 ° or less.

  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 second hole type K2. The second hole type K2 is engraved on the upper hole type roll 30 and the lower hole type roll 31 which are a pair of horizontal rolls. On the circumferential surface of the upper hole type roll 30 (that is, the upper surface of the second hole type K2), a projection 35 projecting toward the inside of the hole type is formed. Further, on the circumferential surface of the lower hole type roll 31 (that is, the bottom surface of the second hole type K2), a projection 36 projecting 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. It is desirable that the tip end angles of the protrusions 35 and 36 be a wedge angle θ1 b of 25 ° or more and 40 ° or less.

  The wedge angle θ1a of the first hole type K1 secures the thickness of the tip of the flange equivalent portion, enhances the inductive property, and secures the rolling stability, the wedge angle of the second hole type K2 in the latter stage It is preferable that the angle be the same as θ 1 b.

  The height (protruding length) h2 of the protrusions 35, 36 is configured to be higher than the height h1 of the protrusions 25, 26 of the first hole type K1, and h2> 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 h2 of the protrusions 35 and 36 formed in the second hole type K2 is higher than the height h1 of the protrusions 25 and 26 formed in the first hole type K1. Similarly, the penetration length to the upper and lower end portions (slab end face) of the second hole type K2 is longer. The penetration depth of the protrusions 35 and 36 into the material to be rolled A in the second hole type K 2 is the same as the height h 2 of the protrusions 35 and 36. That is, the penetration depth h1 'of the projections 25 and 26 in the first hole type K1 into the material to be rolled A and the penetration depth of the projections 35 and 36 in the second hole type K2 into the material to be rolled A h2 is in a relationship of h1 '<h2.
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 second hole type K2, the first hole type K1 is used. The shaping is performed so that the interruptions 28, 29 formed in the above become deeper, and the interruptions 38, 39 are formed. 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 interrupts 38, 39 formed here.

  In addition, although the formation in the second hole type K2 is performed in multiple passes, in the multi-pass formation, the upper and lower end portion (slab end face) of the material to be rolled A in the final pass and the hole upper surface 30a opposite thereto , 30b and the hole-shaped bottom surfaces 31a, 31b are in contact with each other. This is because assuming that the upper and lower end portions of the material to be rolled A do not make contact with the inside of the hole type in all the passes in the second hole type K2, the flange equivalent portion (portion corresponding to the flange portion 80 described later) There is a possibility that the shape defect such as being formed may occur, and there is a problem in the material passing property.

  FIG. 4 is a schematic explanatory view of the third hole type K3. The third hole type K3 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 third hole type K3), a projection 45 projecting 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 third hole type K3), a protrusion 46 protruding 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 θ2 of the protrusions 45 and 46 is wider than the angle θ1 b, and the penetration depth h3 of the protrusions 45 and 46 into the material to be rolled A is the penetration depth of the protrusions 35 and 36 It is shorter than the distance h2 (ie, h3 <h2). The angle θ2 is preferably, for example, 70 ° or more and 110 ° or less.
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, in the third hole type K3, the second hole type K2 is formed at the upper and lower end portions (slab end face) of the material to be rolled A with respect to the material to be rolled A after passing the second hole type K2 When the projections 45 and 46 are pressed, the interrupted interruptions 38 and 39 become interruptions 48 and 49, respectively. That is, in the final pass of the formation in the third hole type K3, the deepest part angle (hereinafter also referred to as an interruption angle) of the interruptions 48 and 49 is θ2. In other words, the second hole type K2 is shaped such that a divided portion (portion corresponding to the flange portion 80 described later) shaped together with the formation of the interruptions 38 and 39 is bent outward.

  In addition, the formation in the third hole type K3 shown in FIG. 4 is performed by at least one or more passes, and at least one or more of these passes are 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. 5 is a schematic explanatory view of the fourth hole type K4. The fourth hole type K4 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 fourth hole type K4), a protrusion 55 which protrudes toward the inside of the hole type is formed. Further, on the circumferential surface of the lower hole type roll 51 (that is, the bottom surface of the fourth hole type K4), a projection 56 projecting 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 θ3 of the protrusions 55 and 56 is wider than the angle θ2, and the penetration depth h4 of the protrusions 55 and 56 into the material to be rolled A is the penetration depth of the protrusions 45 and 46. It is shorter than h3 (ie, h4 <h3).
In addition, the 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 the third As in the case of the hole type K3, all four places shown in FIG. 5 are formed at about 90 ° (approximately right angle).

  In the fourth hole type K4, the interruptions 48 and 49 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 pass The protrusions 55 and 56 are pushed and spread out, resulting in interruptions 58 and 59. That is, in the final pass in the formation in the fourth hole type K4, the deepest part angle (hereinafter also referred to as an interruption angle) of the interruptions 58 and 59 is θ3. In other words, the third hole type K3 is shaped such that a divided portion (portion corresponding to the flange portion 80 described later) shaped together with the formation of the interruptions 48 and 49 is further bent outward. 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. 5 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. 6 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. 6, in the fifth hole type K5, the material to be rolled A shaped up to the fourth hole type K4 is rotated by 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 thickness reduction hole type or a flat modeling hole type because the thickness is reduced by pressing down the web portion 82. 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 shaping the flange portion 80 by bending the portion to the left and right, the shaping of the H-shaped rough section 13 is performed without pressing the upper and lower end surfaces of the material to be rolled A (slab) substantially vertically. It can be carried out. That is, it is possible to form the H-shaped rough section 13 by widening the flange width, as a result, as compared with the rough rolling method in which the slab end face is always pressed, as a result. H-shaped steel) can be manufactured.

  Here, in the method of manufacturing the H-shaped steel according to the present embodiment, the shape of the flange portion 80 of the material to be rolled A shaped by the above-described first through fourth hole types K1 to K4 is the conventional manufacture. Compared with the shape of the flange part before the flat hole type shaping | molding in a method, it is a shape close | similar to the shape of a product flange. This is because a shaping technology is employed in which the division portion (flange portion 80) formed by inserting an interruption is bent without changing the end shape of the material (slab) of the rectangular cross section used as the material. to cause.

Further, in the rolling and forming technology of H-shaped steel represented by such forming technology, in the fifth hole type K5 (flat forming hole type), the reduction ratio of the web portion 82 is relative to the reduction ratio with respect to the flange portion 80. Great. This is attributed to the fact that the reduction of the portion corresponding to the web portion 82 of the material to be rolled A is not performed in the reduction forming up to the fifth hole type K5.

According to the verification of the present inventors, under the reduction of the web portion 82 in the fifth hole type K5 (flat shaped hole type) described above and the pressure reduction of the tip end portion of the flange portion 80, the “shape of the flange portion 80 described above However, the rolling reduction ratio of the web portion 82 is relatively smaller than that of the flange portion in the conventional manufacturing method as compared to the shape of the flange portion before flat hole forming, or “the rolling reduction ratio with respect to the flange portion 80 It was found that there is a problem in the dimensional accuracy and the threadability of the material to be rolled A (particularly, the flange portion 80) because of the large size.
Therefore, the present inventors have examined these problems and, at the same time, did not change the shape of the end portion of the material (slab) of the rectangular cross section used as the above-described material, and formed divided portions (flange 80 In modeling technology which performs processing which bends), it examined further about the technology which can solve the problem concerned. Hereinafter, the above-mentioned problems and the studied contents will be described with reference to the drawings.

First, in the forming method using the first through fourth hole types K1 to K4 according to the present embodiment, after forming with the fourth through hole type K4, a fifth through hole type K5 (flat forming hole type) is used. The problems related to dimensional accuracy and threadability in the process will be described.
FIG. 7 is an explanatory view of a case where the material to be rolled A having been shaped in the fourth hole type K4 is shaped in a plurality of passes including thickness reduction of the web portion 82 using the fifth hole type K5. (A) shows a schematic cross-sectional shape of a steady part in the first half pass of rolling shaping, and (b) shows a schematic cross-sectional shape of the steady part in the second half pass of rolling shaping. In addition, in FIG. 7, in order to show the mode of a shape change of the flange part 80, a part of to-be-rolled material A is expanded and shown in figure so that the flange part 80 may be expanded.

  As shown in FIG. 7, in the fifth hole type K5, the rolling reduction of the web portion 82 is a flange with respect to the material to be rolled A shaped by the first through fourth hole types K1 to K4 according to the present embodiment. Relatively large compared to the rolling reduction of the part 80. Therefore, metal spread (metal flow) in the web height direction (the side wall direction of the flat shaped hole type) occurs when the thickness of the web portion 82 is reduced. In such a case, as shown in FIG. 7 (a), the initial contact start position between the flange 80 and the fifth roll K5 is of a local range (indicated by the broken line in FIG. 7 (a)). It is limited to the part shown). As a result, the contact width between the outer surface of the flange portion 80 and the roll side wall is limited to the flange tip portion, and the surface pressure becomes high, and it becomes a condition that easily causes the generation of the sliding wedge toward the flange central portion. It will

  Further, as shown in FIG. 7 (b), at the same time the flange 80 is pressed to the outside of the flat shaped hole mold 90, the tip of the flange 80 is pulled away from the roll by pull-down, and the flange tip projects inward. Phenomenon (so-called overhang) is likely to occur. Once overhanging occurs, there is a very high possibility that a rubbish will be generated inside the flange in the next step, universal rolling (intermediate rolling). Furthermore, when the thickness reduction amount of the web portion 82 becomes large, the metal flow to the flange portion 80 becomes large, and there is also a concern about shape defects such as bending of the flange portion 80. Moreover, since the change in the shape of the flange portion 80 is large, the material passing property at the time of rolling is deteriorated, and there is a concern that the dimensional accuracy is deteriorated.

  Such problems described with reference to FIG. 7 become more pronounced in the case of manufacturing a (high) H-shaped steel product having a wider flange piece width than in the prior art. This is because the bending deformation of the entire flange portion 80 is more likely to occur and the deformation tends to be concentrated at the tip of the flange portion 80 as the flange piece width formed with respect to the slab thickness of the material is larger. .

  As described above with reference to FIG. 7, in the fifth hole type K5, the web portion of the material to be rolled A shaped by the first to fourth hole types K1 to K4 according to the present embodiment. Since rolling reduction with a reduction ratio of 82 relatively larger than that of the flange portion 80 is performed, various problems are concerned. In view of such problems, the present inventors pay attention to the relationship between the hole shape of the fourth hole type K4 and the hole shape of the fifth hole type K5, and in particular, the hole type of the fourth hole type K4. By making the shape suitable, it solved the problems such as the deterioration of the dimensional accuracy and the threadability, and found that it was possible to implement efficient rolling shaping. The present finding will be described below.

  FIG. 8 is a schematic explanatory view in the case where the shape of the contact surface between the flange portion 80 and the hole type roll is improved in the fourth hole type K 4 described above, and is illustrated as a fourth hole type K 4 ′. Fig. 8 (a) shows the rolled material A before bending and shaping, and Fig. 8 (b) shows the rolled material A after bending. In the fourth hole type K4 'shown in FIG. 8, the components having the same functional configuration as the fourth hole type K4 shown in FIG. 5 will be assigned the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 8, on the circumferential surface of the hole type roll of the fourth hole type K 4 ′, a linear horizontal portion 100 located at both ends of the protrusions 55 and 56 (both ends of the inclined surface of the protrusions) is formed. ing. These horizontal portions 100 have a predetermined length, and as shown in FIG. 8 (b), when the bending and shaping of the flange portion 80 is completed, the tip inner side surface of the flange portion 80 (in the H-shaped steel product The tip end portion of the flange outer surface abuts, and a flange tip side surface portion 80a having a linear shape (flat shape) horizontal to the rolling pitch line is formed. Here, the wedge angle θ3 of the fourth hole type K4 ′ is preferably, for example, 130 ° or more and 170 ° or less.
In addition, the angle θf1 formed by the horizontal surface 100 and the upper surfaces 50a and 50b of the upper and lower end portions (slab end faces) of the material to be rolled A and the lower surfaces 51a and 51b is about 90 ° However, in view of the convenience of roll recovery (roll repair) accompanying roll wear, it may be, for example, about 90 ° + 5 ° to 10 °.

  According to the rolling and forming with the fourth hole type K4 ', as shown in FIG. 8 (b), a state in which the flange tip side surface 80a having a shape horizontal to the rolling pitch line is formed at the tip of the flange 80 The rolling shaping is completed. Then, after the rolling formation with the fourth hole type K4 'is completed, the dimension adjustment of the flange width is performed by pressing down the web portion 82 and pressing the tip end portion of the flange portion 80 in the fifth hole type K5. In this way, a so-called dog-bone shaped H-shaped rough material is formed. In addition, rolling formation in the fourth hole type K4 ′ shown in FIG. 8 is performed by at least one pass or more, and at least one pass or more of these is the upper and lower end portions (slab end face) of the material to be rolled A and the hole type It is performed in a state where the inside (the upper surfaces 50a, 50b and the bottom surfaces 51a, 51b of the fourth hole type K4 ') are in contact with each other. In addition, as shown in FIG. 8 (b), when forming the flange tip side surface 80a at the tip of the flange 80, it is natural that the flange tip side 80a is a hole type roll having a fourth hole type K4 '. The rolling shaping is performed to be in contact with the horizontal portion 100.

Moreover, in rolling and shaping with the fourth hole type K 4 ′, from the viewpoint of securing the centering property of the material to be rolled A, as shown in FIG. 8A, the flange portion 80 before bending and shaping is in the first pass. It is necessary to perform rolling shaping so as to be in contact with the tapered portions (i.e., the inclined surfaces of the projections) of the projections 55, 56. That is, at the start of bending and shaping in the fourth hole type K 4 ′, rolling and shaping are not performed under the condition that the flange portion 80 comes in contact with the horizontal portion 100 first.
Specifically, when the interrupt width (the width at the maximum position of the interrupts 48 and 49 in the final pass) of the interrupts 48 and 49 of the material A rolled and shaped by the third hole type K3 is L1 ( 4), the projection width (the root width of the projection) L2 of the projections 55 and 56 of the fourth hole type K4 'may be designed to be wider than the L1. In view of such conditions, the wedge angle θ2 of the third hole type K3 is preferably 70 ° or more and 110 ° or less, and the wedge angle θ3 of the fourth hole type K4 ′ is 130 ° or more and 170 °, for example. It is preferable that it is the following.

At this time, since the flange tip end side surface portion 80a is formed in the flange portion 80, the contact process of the material to be rolled A with the hole type roll in the fifth hole type K5 is described above with reference to FIGS. It will be different from the case. That is, by rotating the material to be rolled A by 90 ° or 270 °, the rolling shaping with the fifth hole type K5 is performed in such a posture that the flange tip side surface portion 80a is substantially perpendicular to the rolling pitch line. .
Hereinafter, the rolling and shaping with the fifth hole type K5 with respect to the material to be rolled A rolled and shaped by the fourth hole type K4 ′ will be described with reference to FIGS.

FIG. 9 is a schematic explanatory view showing the rolling and shaping of the material to be rolled A in which the rolling and shaping is performed with the fourth hole type K4 'and the flange tip side surface portion 80a is formed. In FIG. 9, components having the same functional configuration as those described above with reference to FIG. 6 are denoted by the same reference numerals, and descriptions thereof will be omitted.
Further, FIG. 10 is a schematic enlarged explanatory view showing rolling shaping of the flange tip side surface portion 80a in more detail, and a shape before rolling in the fifth hole type K5 (broken line in the drawing) and a shape after rolling (solid line in the drawing) ) Are shown together.

As shown in FIGS. 9 and 10, the material to be rolled A, which is rolled and shaped by the fourth hole type K4 ′ and on which the flange tip side surface portion 80a is formed, has a web height at the time of thickness reduction of the web portion 82 in the fifth hole type K5. Even if there is metal spreading (metal flow) in the direction (the side wall direction of the flat formed hole type), the angle of the flange 80 is close to the angle of the side wall of the hole type roll of the fifth hole type K5. Afterward, it is easy to conform to the roll shape, and at an early stage, the flange tip side surface 80a comes into surface contact with the side wall of the fifth hole type K5. As a result, it is possible to suppress or avoid the deterioration of the threadability and the dimensional accuracy described with reference to FIG. 7, and the rolling formation in the fifth hole type K5 can be stabilized. In particular, in the case of producing an H-shaped steel product in which the flange piece width is larger (higher) than that in the prior art, the effect is more remarkable.
In addition, when rolling shaping | molding in such 5th hole type | mold K5 is performed by multiple passes, the rolling shaping | molding in which the flange front end side part 80a mentioned above surface-contacts the side wall of 5th hole type K5 is at least the last Implemented in one or more passes including passes.

  Next, the present inventors should perform rolling shaping using the above-mentioned fourth hole type K4 ', and examine the thickness (slab thickness) of the material to be the object of the present invention technology and the product flange width. The Hereinafter, this examination will be described.

In the fourth hole type K4 'shown in FIG. 8, when manufacturing an H-shaped steel product having a larger flange width (flange piece width) than in the prior art, the tip of the flange portion 80 is a hole type in at least one pass of rolling shaping The rolling shaping is performed in a state of being in contact with the upper surfaces 50a, 50b and the hole-shaped bottom surfaces 51a, 51b. With respect to the material to be rolled A rolled and shaped by the fourth hole type K 4 ′, the present inventors particularly relate to the flange piece width and the flange thickness in the deformation of the fifth hole type K 5 with respect to the form of the deformation of the flange portion 80. In view of the fact that the deformation mode differs depending on the value of ratio I (I = flange piece width / flange thickness), the conditions of the material to which the present invention technology should be applied and the rolling conditions of the fourth hole type K4 ' Did.
In the present embodiment, the ratio I of the flange piece width to the flange thickness in the deformation of the fifth hole type K5 is, as shown in FIG. 6, one width (flange piece width) of one flange portion 80 And the thickness of the flange 80 (flange thickness).

  For example, as described in the non-patent document “The 1995 Spring Conference on Plastic Processing (19785.5.17-19 Hiroshima), pages 209 to 210”, a deformation form by rolling on a material to be rolled with a rectangular cross section ( The deformation mode is mainly divided into a form called single bulging and a form called double bulging. Based on these findings, focusing on the flange portion of H-shaped steel, when applying the roll diameter, rolling reduction, plate width, and plate thickness described in the above-mentioned non-patent document to the usual manufacturing conditions of H-shaped steel, It is known that the boundary between the single bulging and the double bulging is such that the value of the ratio I of the flange piece width to the flange thickness of the rectangular cross section (hereinafter also referred to simply as I) is about 1.30. When I exceeds 1.30, deformation due to rolling is concentrated at the end of the material to be formed into a double bulging shape, and when I is 1.30 or less, deformation due to rolling is concentrated at the center of the material to be rolled It becomes a single bulging shape.

When applied to the flange portion 80 according to the present embodiment, when the shape of the flange portion 80 becomes the double bulging shape, local thickening occurs at the tip of the flange portion 80, and in this state, the flat-modeled hole type When rolling and shaping with the (fifth hole type K5) is performed, wrinkles may be generated at thickened portions, which may cause problems such as shape defects and dimensional accuracy defects.
Therefore, for the flange portion 80 where I exceeds 1.30, the fourth hole type K4 ′ shown in FIG. It becomes possible to suppress wrinkles, and shape defects such as non-uniform deformation of the flange portion can be suppressed, and stable and efficient rolling shaping can be implemented.

The above-mentioned conditions are applied to the thickness of a specific material (slab thickness) as well as to a H-shaped steel product of a desired flange width, and an example is given.
Table 1 shows the values of I when the thickness of the material (generally known slab thickness) is 250 mm and 300 mm, and the flange width of manufactured H-shaped steel is 300 mm, 400 mm, 500 mm and 600 mm It is. In the rolling and shaping according to the present embodiment, since a shape close to the product flange shape is obtained as the shape of the flange portion 80 after the slab edging shaping, a positive reduction of the flange width is not performed. For this reason, the flange piece width after rough rolling and the flange piece width of the H-shaped steel product are approximately equal, and the piece width of the flange portion 80 after rough rolling is 150 mm, which is half the flange width of the H-section steel manufactured. It may be considered as 200 mm, 250 mm, 300 mm.

  As shown in Table 1, in the rolling and forming technique according to the present embodiment, since a forming method is employed in which an interruption is made in the slab thickness and the divided portion is bent, approximately one half of the slab thickness is roughly rolled as it is In order to obtain the final finished flange thickness, when producing H-shaped steel products having a product flange width of 400 mm, 500 mm and 600 mm from a 250 mm thick material, I has a value exceeding 1.30. In addition, in the case of producing H-shaped steel products having a product flange width of 400 mm, 500 mm, and 600 mm from a 300 mm thick material, I is a value exceeding 1.30. That is, in the case of producing an H-section steel under such conditions, it is preferable to apply rough rolling using the fourth hole type K4 'according to the present embodiment, and the H-section steel product having a wide flange It proves to be effective by the manufacture of

  Furthermore, when I is more than 1.30 among the conditions shown in Table 1 above, the present inventors carried out rough rolling to the fifth hole type K5 at the stage where rough rolling was performed on the outer surface of the flange portion 80. It paid attention to what might arise, investigated about the depth of the said ridge, and calculated | required the suitable rolling-reduction ratio based on the relationship between the ridge depth and the rolling-reduction | draft ratio of the flange part 80 in 5th hole type K5.

FIG. 11 shows the rough rolling process using the fourth hole type K4 ′ when I is more than 1.30, and the reduction ratio of the flange portion 80 at the fifth hole type K5 at that time (flange width reduction It is a graph which shows the relationship between the rate (%) and the depth (the weir depth (mm)) of the weir which arises in the outer surface of flange 80 after modeling in the fifth hole type K5.
In addition, it is known that the tolerance value of the weir depth which arises in a material to be rolled in the rough rolling process in manufacture of H section steel is about 0.3 mm generally, and we are about 0.3 mm or less in weir depth. If it is, it is possible to carry out the elimination of the crucible, etc. in the subsequent steps such as intermediate rolling and finish rolling.

As shown in FIG. 11, when I is more than 1.30 and rough rolling is performed using the fourth hole type K4 ′, and then rolling and shaping with the fifth hole type K5 is performed, It can be seen that, within the range where the width reduction ratio of the flange portion 80 in the five-hole type K5 is 20% or less, the greater the width reduction ratio, the shallower the depth of the generated wrinkles. This is because the flange width reduction ratio is increased with respect to the web reduction ratio, which has the effect of suppressing the amount of expansion deformation in the web height direction, and is combined with the hole shape shape improvement technology according to the present invention. It shows that there is a great effect on the suppression of the occurrence of mastication. In particular, in order to satisfy the condition of about 0.3 mm or less which is the allowable value of the weir depth described above, it is understood that the flange width reduction ratio is desirably 10% or more.
That is, in the method of manufacturing an H-section steel according to the present embodiment, the thickness of the material and the width of the H-section steel of which the flange width is I satisfy I described above with reference to Table 1 Under the conditions, by setting the flange width reduction ratio to 10% or more, it becomes possible to make the weir depth generated in the flange portion 80 equal to or less than the allowable value (0.3 mm or less). Stable and efficient rolling shaping can be implemented.

  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.

  In the above embodiment, the material to be rolled A is shaped using four hole types of the first hole type K1 to the fourth hole type K4 ′, and then flat shape rolling is performed using the fifth hole type K5. Although the technology has been described, the number of hole types for carrying out the rough rolling process is not limited to this, and the rolling forming process shown in the first hole type K1 to the fourth hole type K4 'can be performed using more hole types. You may carry it out. 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.

  Moreover, although the slab was illustrated and demonstrated as a raw material at the time of manufacturing H-section steel, this invention is naturally applicable also to the other raw material of a similar shape. That is, for example, it is applicable also when shaping | molding beam blank raw material and manufacturing H-section steel.

  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 (2nd hole type)
31 ··· Lower hole type roll (2nd hole type)
35, 36 ... Protrusions (second hole type)
38, 39 ... Interruption (2nd hole type)
40 ... Upper hole type roll (3rd hole type)
41: Lower hole type roll (third hole type)
45, 46 ... Protrusions (3rd hole type)
48, 49 ... Interruption (3rd hole type)
50 ... Upper hole type roll (4th hole type)
51 ··· Lower hole type roll (4th hole type)
55, 56 ... Protrusions (4th hole type)
58, 59 ... Interruption (4th hole type)
DESCRIPTION OF SYMBOLS 80 ... Flange part 80a ... Flange tip side part 82 ... Web part 85 ... Upper hole type roll (the 5th hole type)
86: Lower hole type roll (fifth hole type)
90: flat shaped hole type 100: horizontal part K1: first hole type K2: second hole type K3: third hole type K4, K4 ': fourth hole type K5: fifth hole type (flat shape hole type)
T: Production line A: Rolled material

Claims (4)

A method of manufacturing an H-shaped steel comprising a rough rolling process, an intermediate rolling process, and a finish rolling process, comprising:
In the rolling mill which performs the rough rolling process, a plurality of five or more hole molds for forming a material to be rolled are engraved.
In the plurality of hole types, one or more pass shaping of the material to be rolled is performed,
Among the plurality of hole types, in the first hole type and the second hole type, projections are formed to form an interruption at the end portion of the material to be rolled by making an interruption vertically to the width direction of the material to be rolled,
Among the plurality of hole types, the third hole type except the last hole type is provided with a projection that abuts on the interrupt and sequentially bends the formed division site, and the last of the plurality of hole types In the last hole type after the third hole type except the hole type, a horizontal portion that forms a flat portion in a straight line shape on the inner side surface of the tip of the divided portion that is bent is provided by connecting to both ends of the protrusion ,
Of the plurality of hole types, the final hole type is a flat shaped hole type, and in the rolling and shaping in the flat shaped hole type, at least in the final pass, the flat portion formed on the inner side of the tip of the divided portion is the flat A method for producing an H-shaped steel, characterized in that the method is carried out in surface contact with a shaped side wall of a shaped hole. Among the plurality of hole types, the tip angle of the protrusion formed in the last hole type after the third hole type excluding the last hole type is 130 ° or more and 170 ° or less, characterized in that The manufacturing method of the described H-section steel. 3. The H-shaped steel according to claim 1, wherein rolling shaping in the last hole type after the third hole type excluding the last hole type among the plurality of hole types is performed in a plurality of passes. Production method. In the rolling and forming with the flat forming hole type, when the ratio I of the flange piece width to the flange thickness is 1.30 or more at the flange portion of the material to be rolled corresponding to the divided portion, the flange of the flange portion The method for producing an H-shaped steel according to any one of claims 1 to 3, which is performed at a width reduction ratio of 10% or more.