Technical field [0001] CROSS REFERENCE TO RELATED APPLICATIONS 　This application is based on Japanese Patent Application No. 2016-157333, filed in Japanese on August 10, 2016, and claims priority, the contents of which are incorporated herein. [0002] 　The present invention relates to a method of manufacturing the H-shape steel slab like a rectangular cross-section as a material. BACKGROUND [0003] 　In the production of H-section steel, and shaped into coarse profile (the rolled material of so-called dog-bone shape) material slab or bloom like extracted from the heating furnace by the rough rolling mill (BD), the intermediate universal rolling machine by then rolling the thickness of the web and the flanges of the crude shaped product, wrought and shaping of the width reduction and the end face flange to the material to be rolled is applied by edger rolling mill close to the intermediate universal rolling mill together . Then, H-shaped steel product by finishing universal rolling machine is shaped. [0004] 　In the manufacturing method of the H-shaped steel, in shaping the rough profile of the called dogbone shape away from the slab material is a rectangular cross section, put an interrupt to the slab end faces in a first caliber of rough rolling step after spread split the interruption in the second and subsequent grooved, or by deep interrupt depth, techniques for erasing the interruption of the slab end faces are known in the subsequent caliber (for example, see Patent Document 1 ). [0005] 　Further, in the production of H-section steel, material end faces of such slabs (slab end surface) after the so-called edging rolling to edging, rotate the material to be rolled 90 ° or 270 °, a flat shaping of performing reduction of the web corresponding section carrying out the rolling are known. In this flat shaped rolling, but rolling and shaping of the flange corresponding portion with pressure of the web corresponding section is performed, in recent years, in view of that large H-beam product is sought, and the large material and material to be rolled If, in a general flat shaped rolling may deformation of elongation and flange corresponding portion of the web height direction, various problems occur, there are cases where modifications of the shape is obtained. Such Specifically, with the pressure of the web corresponding section, the web corresponding section is stretched in the longitudinal direction, a flange corresponding portion is pulled in the drawing is also stretched in the longitudinal direction, the thickness of the flange corresponding portion becomes thinner phenomenon has been a concern. [0006] 　Convex For such a flat shaped rolling, for example, Patent Document 2 selectively performs technology the reduction of the web corresponding section is disclosed, the non-reduction portion is provided at the center of the web corresponding section, which is then formed part erased (corresponding to the raised portions of the present invention), and in the widening of the web corresponding section, is set to be performed the production of H-section steel of a large efficiently. Further, for example, Patent Document 3, a technique for suitably define the scope of the non-pressure portion of the web corresponding section (non-pressure portion) is disclosed, the cross-sectional area of ​​the non-pressure portion to the total cross-sectional area of ​​the material to be rolled 0. it is described that a 6 or more. CITATION Patent Document [0007] Patent Document 1: JP-A-7-88501 JP Patent Document 2: JP 57-146405 Patent Publication Patent Document 3: JP 57-171501 JP Summary of the Invention Problems that the Invention is to Solve [0008] 　As described above, in recent years, it has been desired production of large H-shaped steel products due to the size of the structure or the like. Especially products broadened compared contribute significantly flange strength and rigidity of the H-shaped steel conventionally been desired. Flange to produce a H-shaped steel products that are broadening, it is necessary to shape the large material to be rolled flange width compared with conventionally shaped in the rough rolling step. [0009] 　However, for example, in the technique disclosed in Patent Document 1, put the interruption to the material the end face of such slabs (slab end surface), and edging of that end, a method of performing rough rolling by utilizing the width of spread, there is a limit to the broadening of the flange. That is, the wedge design in order to broadening of the flange in a conventional rough rolling method (interrupt angle design), pressure adjustment, although improved techniques by the width spread such lubrication adjustment is achieved, any method to be the flange width because does not contribute significantly, the width spread ratio indicating the ratio of the spread of the flange width to the edging weight is about 0.8 in the initial stage of the efficiency is the highest conditions of edging, the edging of the same caliber Under the conditions repeatedly, decreases as spread value of the flange width is increased, and finally is known to be about 0.5. Further, the material itself such as slub large, it is conceivable to increase the edging amount, the equipment scale and reduction amount of the rough rolling mill went and is not realized broadening of the sufficient product flanges because of the device limits there are circumstances. [0010] 　Further, when manufacturing a large H-shaped steel products, there is a case of rolling shaping a large coarse profile in the rough rolling step. A large coarse profile rolled shaped differently from the conventional, when shaping the shape of coarse profile more shape close to H-section steel is flat shaped by the technique described in Patent Documents 2 and 3 Doing rolling, it has been found that problems such as deformation of elongation and flange corresponding portion of the web height direction is generated. 　For example, Patent Document 3, and focuses only on the rolling effect in caliber rolling itself when viewed reduction unit (non-pressure portion) provided on the web corresponding section, in a variation in the grooved flange wall thinning It discloses a condition that does not occur. However, in actual operation, for non-pressure portion other than the portion that is selectively pressure, it is necessary to erase at the subsequent stage of the process (pressure), the flange thinning the final after a process of a subsequent stage It would need to be evaluated by cross-sectional shape. 　The present inventors, in view of these points, and evaluated in the entire overall process including erasing of non-pressure portion in the subsequent process. Specifically, as described in the embodiment of the present invention to be described later, for example, 300 thick slab material and the non reduction unit 30% to 50% of the width of the web portion method of the rolled material when It found that increasing the flanges generation efficiency by setting the width, has led to the present invention. [0011] 　In view of the above circumstances, an object of the present invention, the caliber of the rough rolling step using in the production of H-beams, the deep interruption in projections that an acute tip shape on the end face of the rectangular cross-section material such as a slab placed, by sequentially bending the flange portion formed by it, can not suppress the generation of shape defect in the rolled material to produce a large H-beams products flange width efficiently and stably than the conventional It is to provide a manufacturing technique such H-shaped steel. [0012] 　Further, the flat shaped rolling performed after edging rolling, when rolling shaping the coarse profile shaped differently from the conventional, large without causing problems such as deformation of elongation and flange corresponding portion of the web height direction crude perform flat shaped rolling profile, and an object thereof is to provide an efficient and stable manufacturing technology for large H-beams products flange width than conventional. Means for Solving the Problems [0013] 　To achieve the above object, according to the present invention, the rough rolling step, an intermediate rolling step, the manufacturing method of the H-shaped steel having a finish rolling step, the rough rolling process, the predetermined the material to be rolled and edging rolling step of rolling shaped into a substantially dog-bone shape has a flat rolling step of performing rolling of the web portion of the rolled material after edging rolling completion is rotated 90 ° or 270 °, performs the flat rolling process of caliber, the upper and lower grooved rolls of at least one grooved depression portion to form a raised portion on the web portion center of the rolled material is provided on the roll barrel length middle portion of the upper and lower grooved roll, it is formed It said side surface inclination angle α of the raised portion, characterized in that it is set to 30 ° or more, the production method of the H-beams is provided. [0014] 　Wherein the caliber of performing flat rolling step, with respect to the raised portion is the material to be rolled which is formed by rolling the ridges, ridge erase grooved substantially flat rolled shaped web portion is further included it may be. [0015] 　Wherein the caliber of performing flat rolling process, in the material to be rolled, the same time the web portion is substantially flat rolled shaped, or, after the web portion is substantially flat rolled shaped, widening the rolling of the web portion one or more of the wider hole type may further include performing. [0016] 　Wherein the rolling mill to perform the rough rolling step, are engraved six or more of the plurality of grooved rolling shaping the material to be rolled, one or more paths shaping of the material to be rolled is performed in the plurality of grooved, the among the plurality of grooved, the first hole-type and the second grooved protrusions to form a cleavage site into the material to be rolled end put vertically interrupt to the width direction of the material to be rolled is formed, among the plurality of grooved, the third grooved later grooved except caliber of performing the flat rolling process located downstream abutting said interruption, projections successively folding the formed split sites it may be formed. [0017] 　The width of the raised portion formed in the flat rolling process may be set to 50% or less than 30% of the web portion method of the rolled material. [0018] 　The following rectangular section slab thickness 290mm or 310mm may be used as a material. [0019] 　Width of the rectangular cross-section slabs may be 2000 mm. Effect of the invention [0020] 　According to the present invention, placed in a hole-type rough rolling step using in the production of H-beams, the deep interruption in projections that an acute tip shape on the end face of the rectangular cross-section material such as slabs, formed by it by sequentially folding the flange portion that is, by suppressing the generation of shape defect in the rolled material, it is possible to manufacture a large H-beams products flange width efficiently and stably than the conventional. Further, the flat shaped rolling, when rolling shaping the coarse profile shaped differently from the conventional, flat shaped rolling large coarse profile without causing problems such as deformation of elongation and flange corresponding portion of the web height direction It can be performed. BRIEF DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 is a schematic illustration of a production line of H-shaped steel. FIG. 2 is a schematic illustration of a first caliber. 3 is a schematic illustration of a second caliber. 4 is a schematic illustration of a third grooved. 5 is a schematic explanatory view of a fourth grooved. 6 is a schematic explanatory view of a fifth grooved. 7 is a schematic illustration of a sixth grooved. Is a diagram comparing the shape of the flange portion after edging rolling of the flange portion, which is shaped by the first grooved to fourth hole type according to the present embodiment and the shape in FIG. 8 the conventional method . 9 is a schematic explanatory view concerning aspects inclination angle α of the raised portion formed in the fifth hole type. [10] side surface inclination angle of the raised portion α is a graph showing how the changes with pressure ridge. Shown [11] Fifth caliber, sixth grooved, and the transition of the flange width in the case of shaping the H-shaped coarse profile by rolling shaping of a total of 18 passes using three widening grooved in the subsequent stage it is a graph. [12] Based on the data in FIG. 11 is a graph showing the relationship between the flange width increase or decrease of the relief rate and H-shaped coarse profile after molding. 13 is a simulation analysis diagram how the rolling shaping of the rolled material shown schematically in the web portion rolling caliber. 14 is a simulation analysis diagram schematically showing a state of rolling shaping of the material to be rolled at the ridge erase caliber. Is a graph showing a change in the FIG. 15] 2000 mm width slab material and the time of flat shaped rolling since the flange width. DESCRIPTION OF THE INVENTION [0022] 　It will be described below with reference to the drawings, embodiments of the present invention. In the specification and drawings, components having substantially the same function and structure are a repeated explanation thereof by referring to the figures. [0023] 　Figure 1 is an explanatory view of the manufacturing line T of H-beam comprising rolling equipment 1 according to this embodiment. As shown in FIG. 1, the production line T in order from the upstream side, the heating furnace 2, the sizing mill 3, the roughing mill 4, the intermediate universal rolling mill 5, finishing universal rolling mill 8 are arranged. Further, edger rolling mill 9 is provided near the intermediate universal rolling mill 5. In the following, the steel in the manufacturing line T for explanation, collectively described as "the rolled material A", sometimes illustrated with the shape dashed-hatched, or the like as appropriate in each figure. [0024] 　As shown in FIG. 1, the production line T, (the material to be rolled A after) the rectangular cross-section material, for example a slab 11 which has been extracted from the heating furnace 2 is rough rolled in the sizing mill 3 and roughing mill 4. Then, the intermediate rolling in the intermediate universal rolling mill 5. At the time of intermediate rolling, rolling with respect to the flange tip of the material to be rolled (flange corresponding portion 12) is performed by the edger rolling mill 9 as needed. In the usual case, the roll sizing mill 3 and roughing mill 4, Atsushi reduced edging caliber and web portion, so-called flat shaped grooved molding a shape of the flange portion being engraved, through these H-coarse profile 13 in the reverse rolling multiple paths are shaped by using a rolling mill train comprising the H-shaped coarse profile 13 from the two rolling mill of the intermediate universal rolling mill 5 edger rolling mill 9 , reduction of the multiple paths are added, the intermediate member 14 is shaped. The intermediate member 14 is finish rolled to a product shape in the finish universal rolling mill 8, H-shaped steel product 16 is produced. [0025] 　Here, slab thickness T of the slab 11 being extracted from the heating furnace 2, for example, is within 310mm below the range of 290 mm. This is the dimension of the slab material, so-called 300 thick slabs used for manufacturing a large-sized H-beams products. [0026] 　Next, will be described with reference to the drawings grooved structure or pore shape which is inscribed in the sizing mill 3 and roughing mill 4 shown in Figure 1 below. 2 to 7 are schematic illustration of the grooved which is engraved on the sizing mill 3 and roughing mill 4 for rough rolling step. Here, the first hole-type to sixth grooved described, for example it may be all engraved in the sizing mill 3, six of the first grooved to sixth grooved sizing mill 3 and roughing mill 4 hole type may be carved separately. That is, the first hole-type to sixth grooved may be engraved over both the sizing mill 3 and roughing mill 4, may be engraved on one of the rolling mill. The rough rolling step in the normal production of H-beams, are shaped in one or more paths in each of these grooved performed. [0027] 　Although described with hole type in the present embodiment is engraved is illustrated case six, also its caliber number, not necessarily 6 caliber, a plurality of grooved number of 6 or more it may be. For example, it may be configured as providing general widening rolling caliber to the subsequent sixth grooved K6 which will be described later. That may be a suitable caliber configuration for shaping the H-shaped coarse profiles 13. Note that shown in FIGS. 2 to 7, a schematic final pass shape of the rolled material A during molding in the grooved by a broken line. [0028] 　Figure 2 is a schematic illustration of a first caliber K1. The first caliber K1 is engraved on the grooved roll 20 and the lower grooved roll 21 are a pair of horizontal rolls, the material to be rolled A is in roll gap of over grooved roll 20 and the lower grooved roll 21 It is pressure-molding. Further, the peripheral surface of the upper grooved roll 20 (i.e., the upper surface of the first hole-type K1), the protrusion 25 which protrudes toward the inside caliber is formed. Further, the peripheral surface of the lower grooved roll 21 (i.e., the bottom surface of the first hole-type K1), the projections 26 projecting toward the inside caliber is formed. These projections 25 and 26 has a tapered shape, the dimensions of the projecting length and the like are configured equal to each other between the protrusion 25 and the protrusion 26. The height of the protrusions 25 and 26 (projecting length) and h1, the tip angle and .theta.1a. [0029] 　In the first grooved K1, projections 25 and 26 is pressed against the upper and lower ends of the rolled material A (slab end surface), the interrupt 28, 29 are formed. Here, (also wedge angle is referred) tip angle of the projections 25 and 26 .theta.1a is desirably 40 ° or less e.g. 25 ° or more. [0030] 　Here, the caliber width of the first hole-type K1, the thickness of the material to be rolled A (i.e., the slab thickness) is preferably approximately equal to. Specifically, the width of the caliber at the tip of the projecting portions 25 and 26 formed in the first hole-type K1, by the slab thickness in the same, suitably secured lateral centering of the rolled material A It is. Further, with the construction of such caliber dimensions, as shown in FIG. 2, at the time of molding of the first grooved K1, the upper and lower ends of the material to be rolled A (slab end surface), the protrusion some parts 25, 26 and grooved side (side wall) is in contact with the rolled material a, with respect to the slab on the lower end portion which is divided into four elements by the interrupt 29 (site), the first hole it is preferable that positive pressure is not carried out at the top and bottom surfaces of the mold K1. Pressure by the top and bottom surfaces of the grooved is thus degrading the production efficiency will be caused to extend in the longitudinal direction of the rolled material A, the flange (flange portion 80 to be described later). That is, in the first hole-type K1, reduction in the protrusions 25 and 26 when the projections 25 and 26 is pressed against the upper and lower ends of the rolled material A (slab end surface), the interrupt 28, 29 are formed the amount (wedge tip draft amount), amount of reduction in the slab on the lower end portion is sufficiently larger than (the slab end surface reduction rate), thereby interrupt 28, 29 are formed. [0031] 　Figure 3 is a schematic illustration of a second caliber K2. The second grooved K2 is engraved on grooved roll 30 and the lower grooved roll 31 on a pair of horizontal rolls. Circumferential surface of the upper grooved roll 30 (i.e., the upper surface of the second hole-type K2), the projections 35 projecting toward the inside caliber is formed. Further, the peripheral surface of the lower grooved roll 31 (i.e., the bottom surface of the second hole-type K2), the projecting portion 36 projecting toward the inside caliber is formed. These projections 35 and 36 has a tapered shape, the dimensions of the projecting length and the like are configured equal to each other between the protrusion 35 and the protrusion 36. These tip angle of the projections 35, 36 is preferably a wedge angle θ1b of 40 ° or less 25 ° or more. [0032] 　Incidentally, the wedge angle θ1a of the first hole-type K1 secures the tip thickness of the flange corresponding portion to increase the inductive, in order to ensure the stability of the rolling wedge angle of the second hole-type K2 of the subsequent it is preferably the same angle as Shita1b. [0033] 　Height (projecting length) h2 of the projecting portion 35 and 36, the is configured higher than the height h1 of the protruding portions 25 and 26 of the first hole-type K1, it has a h2> h1. The tip portion angle of the protrusion 35 and 36 the first hole-type K1 protrusions 25, 26 of the tip angle same as it is on the rolling dimensional accuracy and, preferably. In the these upper grooved roll 30 roll gap of the lower grooved roll 31, the material to be rolled A after the first hole-type K1 mails material is further shaped. [0034] 　Here, than the height h1 of the protruding portions 25 and 26 formed in the first hole-type K1, higher in the height h2 of the projecting portion 35, 36 formed in the second hole-type K2, the material to be rolled A becomes longer toward the second hole-type K2 similarly on penetration length of the lower section (slab end surface) of the. The rolled material penetration depth into A of the protruding portions 35 and 36 in the second grooved K2 is the same as the height h2 of the projecting portion 35, 36. That is, the material to be rolled penetration depth h1 'to A, penetration depth into the material to be rolled A of the protruding portions 35, 36 of the second grooved K2 of projections 25, 26 of the first grooved K1 h2 is made on the relationship between h1 '