Steel sheet pile manufacturing equipment

Abstract

To provide a steel sheet-pile bending machine which can suppress dimensional variation of a rolled material in a longer direction when deviated engagement of a tip of the rolled material or twist is caused in a bending machine in which asymmetric crop part of the rolled material or bending thereof in a rolling process is formed by asymmetry of a product shape, temperature deviation or deviation between an upper roll and a lower roll in an axial direction during rolling.SOLUTION: A manufacturing apparatus of manufacturing a steel sheet plate by hot-rolling includes: a rough rolling mill; an intermediate rolling mill; a finishing rolling mill; and a bending machine performing a bending forming in succession to the finishing rolling mill of a rolled material. The bending machine consists of one or a plurality of stands including a first stand. A web restraining guide restraining a top face of a web corresponding part of the rolled material is arranged at at least a first stand upstream side of the bending machine. An outer width of the web restraining guide is configured to be smaller than inner side interval between right and left flanges of a portion to be deformed in the stationary state of the rolled material at the position where the web restraining guide is set.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a manufacturing device for steel sheet piles, for example, hat-shaped steel sheet piles, U-shaped steel sheet piles, and the like. [Background technology]

[0002] Steel sheet piles having joints at both ends, such as hat-shaped steel sheet piles and U-shaped steel sheet piles, are manufactured by a groove rolling method as shown in, for example, Patent Document 1. Specifically, it is known that a general process of the groove rolling method is to firstly roll a rectangular material heated to a predetermined temperature in a heating furnace by a roughing mill, an intermediate rolling mill, and a finishing rolling mill each equipped with a groove, in that order.

[0003] In addition, in particular, when manufacturing large and asymmetric products such as hat-shaped steel sheet piles, a large number of grooves are required to manufacture them using the roughing mill, intermediate rolling mill, and finishing rolling mill, and large-scale equipment is required, and the forming method becomes complicated, which makes it easy for the shape of the product to vary or have a defective shape. Furthermore, a large number of rolls are required to manufacture steel sheet piles of different shapes. In response to this, as shown in Patent Document 2, a technique is known in which a steel sheet pile is rolled and manufactured by hot rolling, and then bent by cold working using roll forming (hereinafter also referred to as bending forming), to manufacture a steel sheet pile with a width larger than that of a rolling facility and a steel sheet pile with a high cross-sectional height.

[0004] In addition, Non-Patent Document 1 discloses a technique for manufacturing a lightweight steel sheet pile by using a thin steel plate with a thickness of about 4 to 7 mm as a material, bending the steel plate using multiple cold forming machines. This technique has the advantage that the plate thickness is thinner than that of a hot-rolled steel sheet pile, so that forming is easy, and there is almost no difference in the shape of the cropped parts on the left and right sides because the steel plate is bent almost symmetrically using multiple rolls, so that there is little difference in the shape of the cropped parts on the left and right sides.

[0005] In addition, when manufacturing a steel sheet pile that is asymmetrical in the left and right, it is known that the material to be rolled may warp up and down, bend left and right, twist, etc. at the delivery side of the rolling mill, especially during intermediate rolling and finish rolling. In response to this, for example, Patent Document 3 discloses a technology in which plate-shaped guides (first to third guides) are provided at the entry and exit sides of the rolling mill to prevent warping up and down, bending left and right, twisting, etc. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-192905 [Patent Document 2] JP 2003-230916 A [Patent Document 3] JP 2009-119513 A [Non-patent literature]

[0007] [Non-Patent Document 1] "Roll Forming", edited by the Japan Society for Technology of Plasticity, Corona Publishing, pp. 83-85, 111-113 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the conventional groove rolling method exemplified in the above Patent Document 1, one pass of rolling is performed with one groove while shifting the groove in the intermediate rolling process to the finish rolling process, so that the total elongation of the rolled material is restricted according to the number of grooves to be rolled, and the elongation length of the product is small. Furthermore, when a large steel sheet pile product is manufactured by the conventional groove rolling method, the number of grooves that can be arranged on one roll is reduced, the roll diameter is increased, and the manufacturing efficiency is reduced, and a large rolling machine is required.

[0009] In addition, in the manufacturing method of steel sheet piles as exemplified in the above Patent Document 2, bending is performed by cold working, and furthermore, since the corners of the rolled material are not directly pressed down using the support rolls, which are flat rolls, there are problems that the corners are difficult to directly plastically deform, making it difficult to perform effective bending, and that the springback after forming is likely to be large due to the cold working. In addition, when the web and flange are formed at different times using multiple forming rolls (support rolls), there is also a problem that the efficiency of bending is reduced because the supports are shifted in the longitudinal direction of the rolled material.

[0010] In addition, in the manufacturing method of steel sheet piles described in Patent Document 2, the temperature when bending is performed by cold working is set to a temperature below the A1 transformation temperature or below the recrystallization temperature. If bending is performed in such a temperature range, the processing load is large, and problems such as deterioration of the material, such as a decrease in elongation and toughness, and an increase in residual stress, may occur. Therefore, in order to solve these problems, it becomes necessary to arrange a large number of forming rolls, which causes problems such as an increase in the size of the equipment and a complex structure.

[0011] In addition, the technology described in Non-Patent Document 1 is a cold bending technology, and in cold bending, the steel plate is restrained by pinch rolls and fed in without any cropped areas, while bending is performed in multiple stands. In contrast, when bending is performed continuously with hot rolling, asymmetric cropped areas and bends are likely to be formed in the rolled material, which can easily cause misalignment and jamming. Therefore, it is difficult to apply the technology described in Non-Patent Document 1 to bending of large steel sheet piles performed continuously with hot rolling.

[0012] In addition, in the technology described in the above Patent Document 3, the rolling mill for hot rolling the steel sheet pile is provided with first to third guides in the width direction of the steel sheet pile, aiming at stable rolling. However, there is no mention of a configuration for providing guides suitable for forming such as bending, which involves a large change in cross-sectional shape. In other words, when bending the steel sheet pile after rolling, it is necessary to apply a guide configuration or the like for dealing with the twisting that occurs when the rolled material is bitten into the device and for dealing with the large cross-sectional deformation that occurs at the entry side of the roll bite in the steady state specific to bending, and it cannot be said that it is appropriate to apply the technology described in Patent Document 3 to bending the steel sheet pile.

[0013] In view of the above circumstances, an object of the present invention is to provide a steel sheet pile manufacturing device that can suppress longitudinal dimensional fluctuations of the rolled material without impairing centering properties, even when asymmetric crops or bends are formed in the rolled material during the rolling process due to asymmetry in the product shape, temperature deviation, axial misalignment of the upper and lower rolls during rolling, etc., when manufacturing steel sheet pile products by bending the rolled material after hot finishing rolling, and when misalignment and twisting of the tip of the rolled material occurs in the bending machine. [Means for solving the problem]

[0014] In order to achieve the above-mentioned object, according to the present invention, there is provided a manufacturing apparatus for manufacturing steel sheet piles by hot rolling, comprising a roughing mill, an intermediate rolling mill, a finishing rolling mill, and a bending forming machine that performs bending forming on the rolled material continuously with the finishing rolling, the bending forming machine consisting of one or more stands including a first stand, and a web restraining guide that restrains the upper surface of the web corresponding portion of the rolled material is provided at least upstream of the first stand of the bending forming machine, and the outer width of the web restraining guide is configured to be narrower than the inner distance between the left and right flanges of the pre-deformed portion of the rolled material in a steady state at the installation position of the web restraining guide.

[0015] The roll gap immediately below the upper and lower grooved rolls of the bending machine in the portions facing the web corresponding portion and the flange corresponding portion of the rolled material may be configured to be larger than the thicknesses of the web corresponding portion and the flange corresponding portion, respectively.

[0016] A roller guide may be provided as the web restraining guide, and a transport roller may be provided at a position facing the roller guide with respect to the rolling line.

[0017] As the web restraining guide, a pair of opposing upper and lower roller guides may be provided on the rolling line.

[0018] The transport roller may be provided at the same position as the roller guide or at a position shifted downstream from the roller guide in a plan view.

[0019] Of the pair of upper and lower roller guides, the lower roller guide may be provided at the same position as the upper roller guide or at a position shifted downstream in a plan view.

[0020] The web restraint guide is an inner guide extending in the rolling direction along the inner surface of the rolled material, and the cross-sectional shape of the inner guide may be configured to change continuously from a cross-sectional shape approximating the rolled material after finish rolling to the cross-sectional shape of the rolled material immediately before bending.

[0021] At least one of a lower guide and a transport roller having a substantially flat plate shape extending in the rolling direction along the lower surface of the rolled material may be provided.

[0022] The web restraining guide may be provided to include a position upstream from the roll axis position of the grooved roll of the first stand by a distance L that satisfies the following formula (1). L>L1+L2 (1) Here, L1 is the distance between the bending start position and the roll axis position of the grooved roll of the first stand, and L2 is the crop length of the flange corresponding portion of the rolled material.

[0023] The rolled material may be provided with outer guides extending in the rolling direction on the outsides of both widthwise ends thereof. Effect of the Invention

[0024] According to the present invention, when manufacturing steel sheet pile products by bending the rolled material after hot finishing rolling, even if an asymmetric crop portion or bend is formed in the rolled material and the tip of the rolled material becomes misaligned or twisted in the bending machine, it is possible to suppress dimensional fluctuations in the longitudinal direction of the rolled material without impairing centering ability, and to perform large bending with a small number of stands. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a schematic explanatory diagram of a rolling line. [Diagram 2] FIG. 2 is a schematic cross-sectional side view of a bending machine. [Diagram 3] FIG. 2 is a schematic front view of the bending machine. [Figure 4] FIG. 4 is a schematic enlarged front view showing the hole shape of a first stand. [Diagram 5] FIG. 4 is a schematic enlarged front view showing the hole shape of a second stand. [Figure 6] FIG. 4 is an explanatory diagram of the shape change of a rolled material being bent in a first stand and a second stand. [Figure 7] 1 is a schematic plan view showing a state immediately before the workpiece to be rolled is bitten into the bending machine. FIG. [Figure 8] FIG. 2 is a schematic front view showing how the workpiece is bitten in the bending machine. [Figure 9] FIG. 13 is a schematic plan view of a configuration in which a roller guide is provided. [Figure 10] FIG. 11 is a schematic front view showing how the rolled material is bitten in a configuration provided with roller guides. [Figure 11] FIG. 4 is a schematic side view of a support mechanism for the roller guide. [Figure 12] FIG. 4 is a schematic front view of a support mechanism for a roller guide. [Figure 13] FIG. 11 is a schematic explanatory diagram of a first modified example of the present invention. [Figure 14] FIG. 11 is a schematic explanatory diagram of a second modified example of the present invention. [Figure 15] 14(a) is a schematic cross-sectional view showing the state of the inner guide, the lower guide, the outer guide, and the rolled material in the AA' cross section and the BB' cross section of FIG. 14(a). [Figure 16] 13A and 13B are schematic explanatory diagrams illustrating modified examples of the outer guide. [Figure 17] 1 is a graph showing the results of Comparative Example 1. [Figure 18] 1 is a graph showing the results of Example 1. [Figure 19] This is a schematic explanatory diagram showing the cross-sectional shape of the rolled material A when it is bitten, and the cross-sectional shape of the pre-deformed portion of the rolled material in a steady state, in a cross section perpendicular to the rolling direction including the roll axis of the roller guide. [Figure 20] 1 is a graph showing a numerical analysis of the state of pre-deformation of rolled material A during bending. [Figure 21] FIG. 2 is a schematic explanatory diagram regarding an outer width Q of a roller guide serving as a web restraining guide. [Figure 22] FIG. 13 is a schematic explanatory diagram showing a modified example of the roller guide. [Diagram 23] 13 is a graph for a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and duplicated description will be omitted. In addition, in this embodiment, a case where a hat-shaped steel sheet pile is manufactured as a steel sheet pile product will be described. In the following, for the sake of explanation, the steel material in the rolling line T may be collectively referred to as "rolled material A", and in each drawing, its shape may be appropriately illustrated using dashed lines, solid lines, etc.

[0027] (Outline of the rolling line) Fig. 1 is a schematic explanatory diagram of a rolling line T (indicated by a dashed line in the drawing) as a manufacturing device for manufacturing a hat-shaped steel sheet pile according to an embodiment of the present invention, and rolling machines and the like provided in the rolling line T. In Fig. 1, the rolling proceeding direction of the rolling line T is the direction indicated by the arrow, and the material to be rolled flows in the said direction, and is rolled and bent in each rolling machine and bending machine on the line, thereby forming a product.

[0028] As shown in Fig. 1, in the rolling line T, a roughing mill 10, a first intermediate rolling mill 13, a second intermediate rolling mill 16, a finishing rolling mill 19, and a bending mill 20 are arranged in this order from the upstream. In addition, an edger rolling mill 14 is arranged adjacent to the first intermediate rolling mill 13, and an edger rolling mill 17 is arranged adjacent to the second intermediate rolling mill 16.

[0029] In the rolling line T, a rectangular material (rolled material A) heated in a heating furnace (not shown) is hot rolled in sequence from the roughing mill 10 to the finishing mill 19, and is further hot shaped by the bending machine 20 arranged in a straight line with the finishing mill 19 to become a hat-shaped steel sheet pile, which is a final product. For the sake of explanation, the rolled material A rolled by the roughing mill 10 is also called a rough shaped material, the rolled material rolled by the first intermediate rolling mill 13 and the second intermediate rolling mill 16 is also called an intermediate material, and the rolled material rolled by the finishing mill 19 is also called a finished material 19a. That is, the finished material 19a is shaped (cross-section changed) by the bending machine 20 to become a final product (i.e., a hat-shaped steel sheet pile product).

[0030] Here, the roughing mill 10, the first intermediate mill 13, the second intermediate mill 16, the finishing mill 19 arranged in the rolling line T, and the associated edge mills 14 and 17 are common equipment that have been used conventionally in the manufacture of steel sheet piles, so detailed explanations of their device configurations, etc. will be omitted in this specification.

[0031] (Schematic configuration of bending machine) Next, a detailed configuration of the bending machine 20 will be described with reference to the drawings. FIG. 2 is a schematic side cross-sectional view of the bending machine 20, and FIG. 3 is a schematic front view of the bending machine 20. The bending machine 20 shown in FIGS. 2 and 3 bends a finishing material 19a that has been finish-rolled in a finishing rolling mill 19. FIG. 3 shows a schematic front view of a first stand 22 provided in the bending machine 20 described below. Here, in this embodiment, the bending machine 20 is described as being composed of two forming stands (forming stands 22 and 23 described below), but the bending machine 20 may be composed of one or any number of stands.

[0032] As shown in Fig. 2, the bending machine 20 according to this embodiment includes two forming stands 22, 23 (hereinafter also referred to as the first stand 22 on the upstream side and the second stand 23 on the downstream side) arranged adjacent to each other in tandem. Also, as shown in Fig. 3, each of the stands 22, 23 is provided with a forming groove (groove dies 45, 55 described later) consisting of an upper groove roll and a lower groove roll, and the groove shape is different between the first stand 22 and the second stand 23.

[0033] Here, the roll configuration and the caliber shape of the first stand 22 and the second stand 23 will be described. Fig. 4 is a schematic enlarged front view showing the caliber shape of the first stand 22, and Fig. 5 is a schematic enlarged front view showing the caliber shape of the second stand 23. Fig. 4 shows the cross-sectional shape of the finished material 19a in a state before forming by the bending machine 20 with a dashed line, and Fig. 5 shows the cross-sectional shape of the finished material 19a' in a state before forming by the second stand 23 with a dashed line. In the following, an example will be described in which a rolled material having a substantially hat-shaped shape is bent in an upward opening position (a web-corresponding portion described later is positioned downward, and an arm-corresponding portion is positioned upward).

[0034] As shown in Fig. 3 and Fig. 4, the first stand 22 is provided with an upper perforated roll 40 and a lower perforated roll 41 supported by a housing 44, and a perforated roll 45 is formed by the upper perforated roll 40 and the lower perforated roll 41. The perforated roll 45 has a shape just before a hat-shaped steel sheet pile product (i.e., a shape of a hat-shaped steel sheet pile product) from the part corresponding to the flange to the part corresponding to the joint. The perforated roll 45 changes the angle between the part corresponding to the flange of the finishing material 19a (i.e., the flange corresponding part) and the part corresponding to the web of the finishing material 19a (i.e., the web corresponding part), and the angle between the part corresponding to the arm of the finishing material 19a (i.e., the arm corresponding part), and bends and forms the height and width of the finishing material 19a into a predetermined shape (i.e., a cross-sectional shape similar to the product). In particular, when manufacturing large hat-shaped steel sheet piles, it is preferable to adopt a method in which the rolled material (rough material to finished material 19a) is rolled in a shape with a low height in the rough rolling mill 10 to the finishing rolling mill 19, and then bent in the bending machine 20 so as to increase the height of the rolled material to the desired product height.

[0035] 5, the second stand 23 is provided with an upper perforated roll 50 and a lower perforated roll 51 supported by a housing 54, and a perforated mold 55 is formed by the upper perforated roll 50 and the lower perforated roll 51. This perforated mold 55 has a shape close to the desired product shape, and changes the angle between the part corresponding to the flange (i.e., the flange corresponding part) formed in the first stand 22 of the bending machine 20 and the part corresponding to the web of the finishing material 19a (i.e., the web corresponding part), and the angle between the part corresponding to the arm (i.e., the arm corresponding part), respectively, to form the flange shape, the arm shape, and the joint shape into a predetermined shape (i.e., the product shape). That is, in this second stand 23, the inclination angle of the flange corresponding part, which was insufficient for the product shape in the forming in the first stand 22, is changed to an angle according to the product shape.

[0036] Here, the roll gaps in the grooved dies 45 and grooved dies 55 during bending (the roll gap between the upper grooved roll 40 and the lower grooved roll 41 and the roll gap between the upper grooved roll 50 and the lower grooved roll 51) are configured to be larger than the thickness of the flange-corresponding portion and the web-corresponding portion of the finishing material 19a. That is, in the bending machine 20, the plate thickness of the finishing material 19a is not reduced, and the grooved rolls of the first stand 22 and the second stand 23 and the finishing material 19a are configured to contact each other at some predetermined points described later to perform bending. Specifically, the roll gaps in the portions facing the web-corresponding portion and the flange-corresponding portion are preferably about 0.5 mm to 3 mm larger than the thickness of the flange-corresponding portion and the web-corresponding portion of the finishing material 19a. In addition, the roll gaps in the portions of the grooved dies 45 and grooved dies 55 that overlap the arm-corresponding portion of the finishing material 19a may also be configured to be larger than the thickness of the arm-corresponding portion over the entire cross section.

[0037] (Forming of rolled material in bending) Next, the forming of the rolled material in the above-mentioned stands 22 and 23 will be described. Fig. 6 is an explanatory diagram of the shape change of the rolled material (finished material 19a) bent in the first stand 22 and the second stand 23, (a) shows a schematic cross-sectional view before processing in the first stand 22, (b) shows processing in the first stand 22, and (c) shows processing in the second stand 23. As shown in Fig. 6(a), the finished material 19a is substantially hat-shaped and is composed of a web corresponding part 60 that is substantially horizontal, flange corresponding parts 62, 63 connected to both ends of the web corresponding part 60 at a predetermined angle by a corner part 70, arm corresponding parts 65, 66 connected to the end of each flange corresponding part 62, 63 different from the connection side with the web corresponding part at a predetermined angle by a corner part 71, and joint corresponding parts 68, 69 formed at the tip of the arm corresponding parts 65, 66. Furthermore, the finishing material 19a has a thickness that is approximately the same as the product thickness due to rolling in the finishing rolling machine 19, and the shape of the joint corresponding parts 68, 69 is also approximately the shape of the product joint.

[0038] The finishing material 19a shown in Fig. 6(a) is bent in the groove 45 of the first stand 22 so that the inclination angle θ1 of the flange corresponding parts 62, 63 (angle θ1 of the flange corresponding parts with respect to the horizontal rolling pitch line) becomes large (becomes angle θ2 shown in Fig. 6(b)). By such bending, the finishing material 19a becomes the desired height as shown in Fig. 6(b). That is, in the first stand 22, bending is performed so that the height of the finishing material 19a becomes large. The angle change θ2-θ1 by bending here is defined as the first bending angle Δθ1.

[0039] Next, as shown in FIG. 6(c), in the hole 55 of the second stand 23, bending is performed to change the inclination angle θ2 of the flange corresponding parts 62, 63 to the product angle θ3. That is, as shown in FIG. 6(b) and (c), the inclination angle θ2 of the flange corresponding parts 62, 63 is formed to be the product angle θ3. In bending in each stand, it is preferable to press at least the inside 72 of the corner part 70 which is the connection part between the web corresponding part 60 and the flange corresponding parts 62, 63, and the inside 73 of the corner part 71 which is the connection part between the flange corresponding parts 62, 63 and the arm corresponding parts 65, 66, to sufficiently plastically deform the corner part. Since the inclination angle of the flange corresponding parts 62, 63 may change even after passing through the second stand 23, it is preferable to determine the shape of the hole 55 taking into consideration the angle change. The angle change θ3-θ2 by bending here is defined as the second bending angle Δθ2.

[0040] 6(a) to 6(c), bending may be performed in each stand so as to appropriately change the angle between the flange corresponding parts 62, 63 and the arm corresponding parts 65, 66. The final shape is such that the arm corresponding parts 65, 66 are approximately horizontal and are bent to match the product shape.

[0041] (Problems with crop formation in rolled material before bending) In the rolling line T configured as described above, the rolled material A (finished material 19a) after the finish rolling is bent by the bending machine 20 to manufacture the final product. In this way, the rolled material A is pushed from the finishing rolling machine 19 and bitten into the bending machine 20, and the bending is performed continuously with the finish rolling, which makes biting easy and allows the final product to be manufactured with high productivity. On the other hand, when a steel sheet pile product is manufactured using a slab as a material, the flange thickness of the product is usually larger than the web thickness, so that after the finish rolling, the flange corresponding part at the longitudinal end of the rolled material A precedes the web corresponding part. As a result, it is known that a shape defect part (so-called crop) is generated at the tip of the rolled material A. That is, the present inventors have found that a crop is formed at the tip of the rolled material A just before the biting of the bending machine 20, and various problems occur when the biting of the bending machine 20 is started in this state.

[0042] FIG. 7 is a schematic plan view showing the state immediately before the rolled material A is bitten into the bending machine 20, and shows a part of the longitudinal tip of the rolled material A. As shown in FIG. 7, outer guides 80 arranged on both sides in the width direction of the rolled material A are provided upstream of the first stand 22 of the bending machine 20, and the rolled material A is bitten into the first stand 22 while being guided by the outer guides 80. As shown in the figure, a crop is generated at the tip of the rolled material A after the finish rolling. When the crop is generated, due to the difference in the amount of reduction of the left and right flange corresponding parts 62, 63 caused by the axial misalignment and temperature deviation of the upper and lower rolls during rough rolling to finish rolling, crops of asymmetric length may be generated.

[0043] When the material A to be rolled is bitten into the bending machine 20 in a state where crops with asymmetric lengths have been generated, one of the leading flange corresponding parts (flange corresponding part 62 in the figure) contacts the lower hole type roll 41 of the bending machine 20 first, as shown in Fig. 7. That is, one of the flange corresponding parts contacts the lower hole type roll 41 first, and the flange corresponding part is lifted by contacting the lower hole type roll 41, so that the entire cross section of the material A to be rolled is bitten into the bending machine 20 while tilting obliquely.

[0044] FIG. 8 is a schematic front view showing the biting of the rolled material in the bending machine 20, and is a schematic view of the biting state seen from the stand entry side. For simplification, FIG. 8 shows only the rolls and the rolled material, and omits the housing and the like. As shown in FIGS. 7 and 8, one flange corresponding part (here, flange corresponding part 62) contacts the lower hole type roll 41 before the other flange corresponding part (here, flange corresponding part 63) and is lifted up, so that the entire cross section of the rolled material A is inclined diagonally (counterclockwise in the figure), and the biting progresses in this state. If the biting progresses in this state, the twist generated in the rolled material A becomes large, and there is a risk that the biting of the subsequent rolled material A becomes unstable.

[0045] In addition, when the material A is bitten into the bending machine 20 in a state where a crop with an asymmetric length is generated, if the material A is bent in the longitudinal direction, the widthwise center of the material A may be misaligned with the widthwise center of the rolls (upper perforated roll 40 and lower perforated roll 41) of the bending machine 20. As shown in FIG. 7, an outer guide 80 is provided upstream of the bending machine 20, but the spacing between the outer guides 80 is set at a spacing that allows a certain amount of margin (for example, a margin of several tens of mm) relative to the width of the material A, so that the outer guide 80 alone may not be sufficient. If the material A is bitten into the bending machine 20 in a state where the widthwise center positions of the rolls are misaligned, the twist of the material A increases, and a centering defect called a center shift occurs.

[0046] As described above, when the workpiece A after finish rolling is inserted into the bending machine 20, there is a concern that the workpiece cannot be passed through the bending machine 20 due to instability of insertion, occurrence of twisting, poor centering, etc. The present inventors have recognized such various problems and have earnestly studied solutions to them. Means for solving these problems will be described below.

[0047] (Roller guide configuration) The present inventors have investigated the deformation state of the cross-sectional shape of the material A to be rolled in the bending machine 20, and have conducted intensive studies on means for effectively suppressing instability of biting, occurrence of twisting, poor centering, and the like. For example, as in Patent Document 3, in a rolling mill for rolling steel sheet piles (e.g., hat-shaped steel sheet piles), a technique is known in which the upper and lower surfaces of the web, flange, and arm are restrained by guides installed on the entry side and exit side of the rolling mill, respectively, in order to suppress twisting of the material to be rolled. However, in the bending machine 20 according to the present embodiment, in a steady state, the overall width and height of the material A to be rolled change in the longitudinal direction due to pre-deformation at the roll bite entry side, and even at the same position on the roll bite entry side, the cross-sectional shape of the material A to be rolled changes significantly between the time of biting and the steady state, so that it is difficult and undesirable to restrain the flange and arm from above and below.

[0048] From this perspective, the present inventors have devised a configuration in which a web restraining guide is provided to restrain the web (web corresponding portion 60) of the rolled material A on the upstream side of the bending machine 20 (first stand 22). Below, a configuration in which a roller guide 90 is provided as a web restraining guide will be described with reference to the drawings.

[0049] FIG. 9 is a schematic plan view of a configuration provided with a roller guide 90, showing the state immediately before the rolled material A is bitten into the bending machine 20, and showing a part of the longitudinal tip of the rolled material A. FIG. 10 is a schematic front view showing the state of biting the rolled material A in a configuration provided with a roller guide 90, and is a schematic view of the biting state seen from the inlet side of the bending machine 20. In FIG. 9 and 10, components having the same functional configuration as those in FIG. 7 and 8 may be given the same reference numerals and their description may be omitted. In addition, the roller guide 90 is supported at a predetermined position using a roller support mechanism, a vertical lift mechanism, etc., but these support mechanisms, lift mechanisms, etc. are not shown in FIG. 9 and 10.

[0050] 9 and 10, a roller guide 90 is provided upstream of the first stand 22 of the bending machine 20, located above the web corresponding portion 60 of the material to be rolled A, as a web restraining guide that restrains the web corresponding portion 60 between itself and a conveying table (or conveying rollers) below the material to be rolled A. In the configuration according to this embodiment, a plurality of conveying rollers 95 for conveying the material to be rolled A are provided, and the web corresponding portion 60 is restrained between one of the conveying rollers 95 and the roller guide 90.

[0051] The dimensions of the roller guide 90 can be designed arbitrarily, but preferably, the dimensions should be determined based on the relationship with the cross-sectional shape of the material A to be rolled at the installation position of the roller guide 90. An example of how to determine the outer width Q of the roller guide 90 will be described below. FIG. 19 is a schematic explanatory diagram showing the cross-sectional shape of the material A to be rolled when it is bitten (solid line in the figure) and the cross-sectional shape of the pre-deformed part of the material A in a steady state (broken line in the figure) in a cross section perpendicular to the rolling direction including the roll axis of the roller guide 90. FIG. 20 is a graph obtained by numerically analyzing the state of pre-deformation of the material A to be rolled in bending, where (a) shows the longitudinal change in the steady part of the left and right flange inner interval W, and (b) shows the longitudinal change in the flange corresponding inclination angle (flange angle) θ in the steady part. Note that FIG. 20(a) shows data at positions where the height h from the top surface of the web corresponding part 60 is 200 mm, 250 mm, and 300 mm. 20 indicates the distance from the first stand 22 in the rolling direction, with 0 indicating directly below the first stand 22. In FIG.

[0052] As shown in FIG. 20(a), at any position where h is 200mm, 250mm, or 300mm, the left and right flange inner distance W changes due to pre-deformation compared to the left and right flange inner distance W0 before forming. For example, looking at the position h=250mm, 2.5m upstream of the first stand 22 (-2500mm position in the graph), it can be seen that the left and right flange inner distance W is reduced by about 170mm from before forming due to pre-deformation. From this result, it can be said that it is desirable to design the outer width Q of the roller guide 90 as a web restraining guide to be smaller than the left and right flange inner distance W when pre-deformation occurs in the steady state. This can suppress twisting during biting and prevent the occurrence of defects in the pre-deformed portion in the steady state.

[0053] 20(b), it can be seen that the flange angle θ in the longitudinal direction also changes significantly due to pre-deformation in the steady portion of the rolled material A. From this result, it is possible to evaluate the outer width Q of the roller guide 90 as a web restraining guide based on the value of the flange angle θ and design it so that it is located inside the flange.

[0054] The outer width Q of the roller guide 90 as a web restraining guide designed as described above is preferably the outer width of the entire structure including the roller guide 90 main body and the roller support part 105 described later. Here, the width Q of the entire structure of the roller guide 90 and the roller support part 105 may differ depending on the height direction position. FIG. 21 is a schematic explanatory diagram of the outer width Q of the roller guide 90 as a web restraining guide. As shown in FIG. 21, the width Q of the entire structure of the roller guide 90 and the roller support part 105 differs depending on the height direction position, and may be only the roll main body width Q1 or the width Q3 of the entire roll and the support part. Therefore, as described above with reference to FIG. 20(a), when the outer width Q of the roller guide 90 is designed based on the relationship between the height h from the top surface of the web corresponding part 60 when pre-deformation occurs in the steady part and the inner distance W between the left and right flanges, or as described above with reference to FIG. 20(b), when the outer width Q of the roller guide 90 is designed based on the value of the flange angle θ, the outer width Q used in the design may be the outer width Q (Q1 to Q3) at a suitable position such as Q1 to Q3 depending on the position.

[0055] 9, when the roll axis position of the grooved roll of the first stand 22 is P1 and the roll axis position of the roller guide 90 is P2 in a plan view, the roller guide 90 is provided so that the roll axis position P2 is located at a position separated by a predetermined distance L upstream from the roll axis position P1. At least one of the transport rollers 95 needs to be provided in a position substantially below the roller guide 90 (a position facing the roller guide 90 in the rolling line T), and for example, at least one of the transport rollers 95 may be provided in the same position as the roll axis position P2 of the roller guide 90 in a plan view as shown in FIG.

[0056] Here, the installation position of the roller guide 90 on the upstream side of the first stand 22 of the bending machine 20 must be such that the web corresponding portion 60 can be restrained at the stage when the leading flange corresponding portion 62 contacts the lower hole type roll 41 of the first stand 22. Specifically, the roller guide 90 must be provided so as to have a positional relationship in which the distance L between the roll axis positions P1 and P2 is greater than the sum (L1+L2) of the distance L1 between the position where the tip of the leading flange corresponding portion 62 starts to contact the lower hole type roll 41 (i.e., bending start position) and the roll axis position P1 of the lower hole type roll 41 (or the upper hole type roll 40) and the crop length L2 of the flange corresponding portion 62 occurring with respect to the web corresponding portion 60. That is, the position where the roller guide 90 is provided must be provided upstream from the roll axis position P1 of the grooved roll of the first stand 22 by a distance L that satisfies the following formula (1). L>L1+L2 (1)

[0057] The crop length L2 of the flange corresponding portion 62 generated with respect to the web corresponding portion 60 is a value that changes depending on the elongation difference between the web corresponding portion 60 and the flange corresponding portion 62 and operational fluctuations, and is a value that differs for each individual rolled material. Therefore, the maximum value of the crop length L2 may be arbitrarily determined depending on the product size and operational conditions.

[0058] In addition, the distance L1 between the position where the tip of the preceding flange corresponding portion 62 starts to contact the lower hole type roll 41 and the roll axis position P1 of the lower hole type roll 41 can be determined by a geometric relationship. Specifically, the distance L1 can be determined using the following formula (2) from the flange line length B of the rolled material A, the inclination angle θ1 of the flange corresponding portion before bending, the inclination angle θ2 of the flange corresponding portion after bending in the stand (here, the first stand 22), the arm radius Ra and web radius Rw of the lower hole type roll 41, and the center deviation amount X, as shown in Figures 9 and 10. Note that the center deviation amount X is the deviation amount between the width direction center position of the rolled material A and the width direction center position of the grooved roll of the first stand 22 (a state in which the width direction center position of the rolled material A is shifted toward the preceding flange side with respect to the width direction center of the grooved roll is a positive value). TIFF0007648881000001.tif33164

[0059] As an example, under manufacturing conditions where the flange line length B is 542 mm, θ1 is 30°, θ2 is 50°, Ra is 912 mm, Rw is 497 mm, and X is 30 mm, L1 is 607 mm. For example, if the crop length L2 is 900 mm, the roller guide may be installed at a position where the distance L from the roll axis position P1 is more than 1507 mm. It is preferable to set the distance L with a margin in consideration of fluctuations in the distances L1 and L2 during operation.

[0060] (Roller guide support mechanism and lift mechanism configuration) When providing the roller guide 90 according to the present embodiment described above, the support mechanism, lifting mechanism, etc. may be provided as desired, and various configurations are possible, such as providing a housing separate from the bending machine 20 and supporting the roller guide 90 with that housing, or attaching the support mechanism and lifting mechanism to the housing 44 of the first stand 22 of the bending machine 20 to support the roller guide 90. Here, as an example, a configuration in which the support mechanism and lifting mechanism are attached to the housing 44 of the first stand 22 to support the roller guide 90 is illustrated and described.

[0061] Fig. 11 is a schematic side view of the support mechanism of the roller guide 90, and Fig. 12 is a schematic front view of the support mechanism of the roller guide 90. For simplification, Figs. 11 and 12 focus on the first stand 22 of the bending machine 20, and Fig. 12 is a schematic front view seen from the inlet side (upstream side) of the first stand 22. Moreover, the material A to be rolled is not shown in Fig. 11, and the roller guide 90 is shaded in Figs. 11 and 12.

[0062] 11, the first stand 22 is provided with a guide support part 100 that is fixed to a housing 44 of the stand and extends toward the upstream side of the stand, and a lifting mechanism 103 that is attached to the guide support part 100. In addition, a roller guide 90 is rotatably attached to the lower end of the lifting mechanism 103 via a roller support part 105. The lifting mechanism 103 is formed of, for example, a hydraulic cylinder, and can raise and lower the roller guide 90 and the roller support part 105 together to any height by driving the lifting mechanism 103.

[0063] The roll width of the roller guide 90 can be designed as desired, and as a width for preventing shifting of the rolled material A in the width direction and for enabling stable restraint, the roll width is preferably, for example, 2 / 3 or more of the width length of the web corresponding part 60. The roll diameter of the roller guide 90 can be designed as desired according to the scale of the equipment such as the guide support part 100 and the roller support part 105, and may be designed to be, for example, 500 mm or more.

[0064] In this manner, the roller guide 90 provided in a configuration including the lifting mechanism 103 and the transport roller 95 can effectively restrain the web corresponding portion 60 of the rolled material A on the upstream side of the first stand 22. In particular, an effective restraining effect can be achieved by appropriately raising and lowering the roller guide 90 according to the deformation state and thickness of the rolled material A.

[0065] (Action and effect) As described above with reference to the drawings, according to the bending machine 20 (particularly the first stand 22) configured with the roller guide 90 according to the present embodiment, when the longitudinal end of the rolled material A is bitten into the bending machine 20, even if the flange corresponding portion 62, which is ahead of the web corresponding portion 60, is bitten first, the web corresponding portion 60 is restrained, thereby suppressing misalignment and twisting during biting. This suppresses material passing defects during bending, and improves centering of the rolled material A.

[0066] In particular, when providing the roller guide 90, by setting the roller guide 90 at a suitable installation position determined by the above formulas (1) and (2), the web corresponding portion 60 can be restrained at the stage when the preceding flange corresponding portion 62 contacts the lower hole type roll 41 of the first stand 22, and an effective restraining effect can be obtained. As a result, even when a large bending process is performed in the first stand 22, an asymmetric crop portion is formed in the rolled material, and even if the preceding flange corresponding portion 62 is bitten first, the rolled material is kept in a centered state while being bent, thereby avoiding a situation in which the material is not evenly bitten and causes a material passing failure.

[0067] As described above, the roll gap immediately below the roll of the groove 45 during bending is configured to be larger (for example, about 0.5 mm to 3 mm) than the thickness of the flange corresponding portion and the web corresponding portion of the finishing material 19a. In addition, it is preferable to configure the roll gap immediately below the roll of the groove 45 during bending to be larger than the thickness of the arm corresponding portion and the corner portion (the connecting portion of the web corresponding portion and the flange corresponding portion, and the connecting portion of the flange corresponding portion and the arm corresponding portion) of the finishing material 19a. As a result, when the flange corresponding portions 62 and 63 are misaligned and bitten, the rolled material A is bitten into the groove 45 while the web restraining guide suppresses twisting, which has a great effect of correcting the misalignment and facilitating centering.

[0068] Although an example of an embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0069] For example, in the above embodiment, the bending machine 20 is illustrated and described as being composed of the first stand 22 and the second stand 23, but the scope of application of the present invention is not limited to this. For example, the bending machine 20 may be a single stand, or may be composed of any number of multiple stands. When the bending machine 20 is composed of multiple stands, bending can be shared among the stands. The number of stands is appropriately determined based on a balance between the bending angle and the capital investment.

[0070] In the above embodiment, the roller guide 90 as a web restraining guide is illustrated as being configured to restrain the web corresponding portion 60 between the roller guide 90 and a conveying table (or conveying roller) below the material A to be rolled (see Figs. 9 to 11), but the configuration of the roller guide 90 is not limited to this. For example, as shown in Fig. 22, the roller guide 90 may be configured as a pair of upper and lower roller guides (upper roller guide 90a and lower roller guide 90b). In such a configuration, the upper roller guide 90a and the lower roller guide 90b may be disposed at the same position in the rolling direction in a plan view, or the lower roller guide 90b may be disposed shifted downstream.

[0071] In the above embodiment, the upper and lower hole type rolls of the bending machine 20 can be configured to drive only one of the upper and lower rolls and not drive the other. By configuring to drive only one of the upper and lower hole type rolls, it becomes easier to balance the speed of the material when bending is performed in tandem with multiple stands, and the generation of tension in the material to be rolled due to the imbalance in the speed balance between the multiple stands is suppressed, stabilizing the material to be passed and suppressing unnecessary shape changes in the material to be rolled. In addition, the driving mechanisms such as the motor, spindle, and gear for driving the rolls can be simplified, which realizes miniaturization of the equipment and reduction of equipment costs.

[0072] In the above embodiment, the roller guide 90 is provided upstream of the first stand 22 of the bending machine 20, but a similar roller guide 90 may be provided in each of the multiple stands constituting the bending machine 20. In this case, bending can be performed efficiently because bending is performed without impairing the centering ability of the rolled material in all of the multiple stands, and problems such as poor material passing can be avoided.

[0073] (First Modification of the Invention) In the above embodiment, when the rolled material A is restrained on the upstream side of the first stand 22, the web corresponding portion 60 is restrained by the roller guide 90 and the transport roller 95 located substantially below it, but the positional relationship between the roller guide 90 and the transport roller 95 is not limited to this. Here, as a first modified example of the present invention, a configuration in which the position of the transport roller 95 facing the roller guide 90 is shifted will be described.

[0074] FIG. 13 is a schematic explanatory diagram of a first modified example of the present invention. In FIG. 13, components having the same functional configuration as those in FIG. 9 described in the above embodiment may be given the same reference numerals, and their description may be omitted. As shown in FIG. 13, in the first modified example of the present invention, the roll axis position of the transport roller 95 located approximately below the roller guide 90 is shifted toward the first stand 22 side (i.e., downstream side) in a plan view. In this way, by adopting a configuration in which the transport roller 95 is disposed downstream of the roller guide 90 in a plan view and the web corresponding portion 60 of the rolled material A is restrained by the roller guide 90 and the transport roller 95, it is possible to more effectively suppress the twisting of the tip portion (so-called crop) of the rolled material A, and to stably perform bending forming.

[0075] (Second Modification of the Invention) In the above embodiment, a configuration in which a roller guide 90 is provided as a web restraining guide that restrains the rolled material A on the upstream side of the first stand 22 has been illustrated and described, but the configuration of the web restraining guide is not limited to this. That is, an inner guide and a lower guide extending in the rolling direction (direction in which the rolled material passes) in a region including the upstream side of the first stand 22 may be provided as the web restraining guide. Here, as a second modified example of the present invention, a configuration in which an inner guide 110 and a lower guide 112 are provided in the first stand 22 as web restraining guides will be described.

[0076] Fig. 14 is a schematic explanatory diagram of a second modified example of the present invention, in which (a) is a schematic explanatory diagram of an inner guide 110 and a lower guide 112 provided on a first stand 22 as viewed from the side, and (b) is a schematic explanatory diagram of an inner guide 110, a lower guide 112, and an outer guide 80 as viewed from the front. Note that Fig. 14(a) illustrates some of the transport rollers 95, and Fig. 14(b) omits components other than the inner guide 110, the lower guide 112, and the outer guide 80 for simplification. In Fig. 14, components having the same functional configuration as those in Figs. 1 to 12 described in the above embodiment are denoted by the same reference numerals, and their description may be omitted.

[0077] As shown in Fig. 14(a), the inner guide 110 and the lower guide 112 extend in the rolling direction from the upstream to the downstream of the first stand 22, and in the vicinity of the first stand 22, the inner guides 110a, 110b and the lower guides 112a, 112b are arranged on the upstream and downstream sides of the first stand 22. That is, the rolled material A during bending is bitten into the first stand 22 while being guided (restrained) from both above and below by the inner guide 110a, the conveying roller, and the lower guide 112a on the upstream side of the stand. Note that Fig. 14 illustrates the vicinity of the first stand 22, and the inner guides 110a, 110b and the lower guides 112a, 112b are described, but an inner guide and a lower guide may also be provided on the downstream side of the second stand 23.

[0078] 14(b), the inner guide 110a protrudes downward from above the rolling line T, and its shape is similar to the shape of the material A to be rolled. That is, the lower surface of the inner guide 110a is shaped to fit the upper surface of the web of the material A to be rolled, which is substantially hat-shaped. Similarly, the shape of the inner guide 110b installed on the downstream side of the stands may be designed to match the shape of the material A to be bent in the second stand 23.

[0079] 14, the lower guide 112a has a substantially flat plate shape and is disposed so as to follow the lower surface of the web of the material A to be rolled when it is bitten. In this manner, the material A to be rolled is bitten into the first stand 22 with its upper and lower surfaces guided by the inner guide 110a, the transport rollers and the lower guide 112a.

[0080] Here, as described above, the shape of the inner guide 110a is close to the shape of the material A to be rolled, but the shape of the central portion from the web corresponding portion to the flange corresponding portion is configured to change in accordance with the change in shape of the material to be rolled in the rolling direction in a steady rolling state, and changes continuously along the rolling direction (longitudinal direction of the material A to be rolled). Figures 15(a) and (b) are schematic cross-sectional views showing the state of the inner guide 110a, lower guide 112a, outer guide 80, and material A to be rolled in the A-A' and B-B' cross sections of Figure 14(a). As shown in Figures 15(a) and (b), the A-A' cross section on the upstream side of the inner guide 110a has a shape that corresponds to the cross-sectional shape of the rolled material A immediately after finish rolling, which is the previous step before bending, has been completed (finishing material 19a in the figure), and the B-B' cross section just before bending in the first stand 22 begins has a shape that corresponds to the cross-sectional shape of the rolled material A (finishing material 19c in the figure) which has undergone pre-deformation and has a larger flange angle than the upstream side, so that the cross-sectional shape of the guide changes continuously in the longitudinal direction.

[0081] In this way, the angle between the web corresponding portion and the flange corresponding portion of the rolled material A (finished material 19a) gradually changes due to pre-deformation until the position where bending in the first stand 22 starts. Therefore, by changing the side angle of the inner guide 110a in the longitudinal direction between the A-A' cross section on the upstream side and the B-B' cross section in accordance with the change in angle between the web corresponding portion and the flange corresponding portion of the rolled material A, the centering property of the rolled material A can be improved without generating guide defects. Regarding the change in the longitudinal cross-sectional shape due to this pre-deformation, for example, the change in the cross-sectional shape from the start position of pre-deformation to the start position of bending may be predicted by simulation, and the guide shape may be determined. Alternatively, the guide shape may be set so as to linearly connect the shape of the rolled material A and the shape of the caliber 45 of the first stand 22. Also, as shown in Figures 15(a) and 15(b), substantially horizontal parts may be provided on both sides of the inner guide 110a to guide the arm portion or joint portion of the rolled material. Even in this case, since the inner guide 110a can restrain the upper surface of the web even if twisting occurs due to misalignment, when the inner guide 110a is provided, it is preferable to configure it so that, as an example of its installation position, position L that satisfies the above formula (1) is located between the A-A' cross section and the B-B' cross section upstream of the roll axis position P1 of the grooved roll of the first stand 22. Moreover, the longitudinal length of the lower guide 112a is arbitrary, and may be extended to the A-A' cross section position in FIG. 14, for example.

[0082] As shown in Figure 14, in order to stably guide the rolled material A (finished material 19a) within the guide even if it is bent or warped, it is desirable to change the shape of the inner guide 110a so that the tip of the inner guide 110a has a shape that widens upward and narrows further upstream of the A-A' cross section, and so that the shape of the inner guide 110a roughly follows the cross-sectional shape on the upstream side toward the A-A' cross section.

[0083] In addition, the length of the inner guide 110a of the first stand 22 in the rolling direction (longitudinal direction) is preferably, for example, from just below the roll to the A-A' cross section, up to a position on the upstream side that is 2 m or more away. This is because, in the case of bending in the present embodiment, pre-deformation of the rolled material occurs from 2 m or more upstream just below the roll in a steady state, so by setting the tip position of the guide 2 m or more upstream just below the roll and setting the shape of the tip side of the guide (the side far from the bending machine 20, for example, the A-A' cross section) to approximately match the cross-sectional shape of the rolled material A (finished material 19a), it is possible to perform bending without generating guide defects even in a steady state while ensuring the inductivity of the tip of the rolled material A. Here, it is necessary to provide a slight clearance between the rolled material A and the inner guide 110a.

[0084] In addition, it is desirable that the A-A' cross section position of the inner guide 110a is located 2 m or more upstream from just below the roll, but this distance is within the permissible range even if it is somewhat shorter, for example, 1.8 m or more. In this case, the guide shape at the A-A' cross section may be matched to the shape of the rolled material that has undergone some pre-deformation. In addition, if the distance from just below the roll to the A-A' cross section position is large and it is difficult to continuously arrange the inner guide 110a from the position where pre-deformation occurs to just before bending in the first stand 22 begins, it is possible to obtain an effect by arranging the inner guide 110a within a suitable range in the longitudinal direction.

[0085] In this modification, the distance between the lower surface of the inner guide 110a and the lower guide 112a is preferably 1.5 to 3 times the thickness of the web corresponding portion of the material A to be rolled, from the viewpoint of suppressing guide defects and stably guiding the material A. In addition, the gap between the lower surface of the inner guide 110a and the upper surface of the web corresponding portion of the material A to be rolled in the material passing state is preferably 3 mm or more and not more than the thickness of the web corresponding portion of the material A to be rolled, from the viewpoint of suppressing guide defects and stably guiding the material A.

[0086] As shown in FIG. 14(b), the outer guide 80 is composed of a right guide 80a and a left guide 80b, which are installed on both sides in the width direction of the material A (finished material 19a) when the material is passed through, and each guide has a substantially flat plate shape extending in the rolling direction. The right guide 80a and the left guide 80b are provided at a predetermined interval, and the interval does not change in the rolling direction. That is, the predetermined interval is a length that matches the overall width of the material A (finished material 19a) before bending in the first stand 22. When the guide is provided in the second stand 23, the length is a length that matches the overall width of the material A after passing through the first stand 22. Here, the overall width refers to the width of the material A in the left-right direction, and the length that matches the overall width refers to a length obtained by adding a clearance of, for example, about 10 mm to a representative value of the overall width of the material A to be rolled, taking into account the variation in the overall width.

[0087] The configuration according to the second modified example of the present invention has been described above with reference to Figs. 14 and 15. However, the shapes and arrangements of the guides described here are merely examples, and the present invention is not limited thereto. For example, the roller guide 90 according to the above embodiment may be combined with the inner guide 110 of this modified example, and a configuration in which the roller guide 90 is incorporated into the inner guide 110, or the inner guide 110 is added between the roller guide 90 and the first stand 22, may also be considered. Also, as shown in Fig. 16, the upstream tip of the outer guide 80 may be shaped to open outward, so that the material A to be rolled can be stably guided into the guide even if it is curved. Also, a configuration in which a guide mechanism for roughly adjusting the center position of the material A in the left-right direction is installed separately from the outer guide 80 on the further upstream side of the outer guide 80 may also be considered.

[0088] In the above description of the embodiment and its modified examples, the case of manufacturing a hat-shaped steel sheet pile as a final product has been taken as an example, but the present invention is not limited to this and can also be applied to the manufacture of steel sheet pile products such as U-shaped steel sheet piles. EXAMPLES

[0089] (First embodiment) As a first example of the present invention, an aluminum model experiment was conducted to evaluate material passing properties for bending at one stand (for example, see the first stand 22 described in the above embodiment). The operating conditions in the experiment were, in actual machine equivalent values, a constant flange line length of the rolled material of 542 mm, Ra of 912 mm, crop length L2 of 530 mm, differences in left and right flange crop lengths of 0, 150, and 300 mm, and center offsets of ±15 and ±30 mm. The flange angle of the rolled material before bending (θ1) and the bending angle (Δθ1=θ2-θ1) were as shown in Table 1 below.

[0090] [Table 1]

[0091] Under the above operating conditions, a model experiment was carried out on a rolled material having a substantially hat-shaped shape in a stand without roller guides as Comparative Example 1, and the material passing properties were evaluated. Figure 17 is a graph showing the results of Comparative Example 1, where ◯ indicates stable material passing and × indicates unstable material passing.

[0092] Also, under the above operating conditions, in Example 1, a roller guide was installed 2.5 m upstream of the stand, and the guide was designed so that the rolled material would not come into contact with it even at the maximum flange angle of 51° of the pre-deformation section in the steady state at the roller guide installation position under any of the conditions in Table 1, and a model experiment of bending a roughly hat-shaped rolled material was carried out with the gap between the web top surface of the rolled material and the roller guide set to 10 mm, to evaluate material passing properties. Figure 18 is a graph showing the results of Example 1, where ◯ indicates stable material passing and × indicates unstable material passing.

[0093] Model experiments were conducted under the five conditions shown in Table 1 for both Comparative Example 1 and Example 1, but as shown in Fig. 17, in Comparative Example 1, the biting became unstable under three of the five conditions, resulting in failure to pass the material through. On the other hand, as shown in Fig. 18, in Example 1, the material could be passed stably under all five conditions. In other words, it was found that by installing the roller guide, the conditions (bending angle) under which bending can be performed in a state where the material can be passed stably are increased, and bending can be performed effectively.

[0094] (Second Example) As a second embodiment of the present invention, a hat-shaped steel sheet pile with a total width of 1400 mm, height of 501 mm, flange angle of 63°, web thickness of 17.0 mm, and flange thickness of 13.2 mm was manufactured by bending after finish rolling. In the second embodiment and the second comparative example, the bending conditions were set to two stages, from the flange angle of 30° after finish rolling to 50° in the first stand and 63° in the second stand.

[0095] In Example 2, a roller guide was provided, the flange line length of the rolled material was constant at 542 mm, Ra was 912 mm, and the spacing of the outer guides was 30 mm wider than the full width of the rolled material. The distance L1 was 598 mm, the maximum value of the crop length L2 was 900 mm, and the distance L from the roller guide was set to 2.5 m. The roll width of the roller guide was set to 90% of the width length of the web corresponding part of the rolled material, and the guide was designed so that the rolled material would not come into contact even with a flange angle of 37 ° of the pre-deformation part in the steady state at the roller guide installation position, and the gap between the web upper surface of the rolled material and the roller guide was set to 10 mm. On the other hand, in Comparative Example 2, except for the configuration in which the roller guide was not provided, manufacturing was performed under the same conditions as in Example 2.

[0096] In Comparative Example 2, which is a configuration without a roller guide, twisting occurred immediately after the tip of the rolled material was bitten by the first stand of the bending machine, and many materials could not be passed through due to large misalignment. On the other hand, in Example 2, which is a configuration with a roller guide, stable bending was performed and good hat-shaped steel sheet piles were manufactured.

[0097] (Third Example) As a third embodiment of the present invention, a hat-shaped steel sheet pile having an overall width of 900 mm, height of 368 mm, flange angle of 69°, web thickness of 15.0 mm, and flange thickness of 11.3 mm was bent by installing a web restraint guide as shown in Figure 14 upstream of the first stand. The guide shape was determined by simulation analysis, and the shape of the web restraint guide was determined based on the results of the analysis, and bending was performed.

[0098] FIG. 23 shows the results of a simulation of the change in the flange-corresponding inclination angle (flange angle) θ of the material to be rolled in bending in the steady state, with the flange angle immediately below the roll of the first stand set to 0. As shown in FIG. 23, the flange angle after finish rolling is 40°, and the flange angle starts to change from a position about 3 m upstream from immediately below the roll of the first stand. Here, the change in the flange angle is small up to about 2 m upstream from immediately below the roll. Therefore, the A-A' cross-sectional position of the inner guide 110a of the web restraining guide was set 2 m upstream from immediately below the roll of the first stand, and the B-B' cross-sectional position was set 0.68 m upstream from immediately below the roll of the first stand. In addition, the side angle of the inner guide at the A-A' cross-sectional position and the B-B' cross-sectional position was set to match the flange angle of the material to be rolled at each position in FIG. 23, the gap between the inner guide and the inner flange inner surface was set to 5 mm, and the flange angle was changed linearly between the A-A' cross-sectional position and the B-B' cross-sectional position. The spacing between the outer guides is set to 30 mm wider than the overall width of the rolled material. In this case, L1 is 397 mm, and even if the crop length L2 is 700 mm, the A-A' cross section position is larger than L1 + L2.

[0099] In manufacturing the hat-shaped steel sheet pile with the above dimensions, guides (inner guide, outer guide) with a shape determined based on Fig. 23 were installed and bending was performed. As a result, it was confirmed that the twisting of the rolled material A during biting could be suppressed and the centering ability could be improved without generating guide defects in the steady state. [Industrial Applicability]

[0100] The present invention can be applied to an apparatus for manufacturing steel sheet piles, such as hat-shaped steel sheet piles and U-shaped steel sheet piles. [Explanation of symbols]

[0101] 10...Roughing mill 13…First intermediate rolling mill 14…Edger rolling machine 16…Second intermediate rolling mill 17…Edger rolling machine 19…Finishing rolling mill 19a…Finishing material 20...Bending machine 22…1st Stand 23…Second stand 40…Upper perforated roll (of the first stand) 41…(First stand) Pre-drilled roll 44…(1st stand) cabinet 45…(1st stand) hole type 50...Upper perforated roll (of the second stand) 51...(Second stand) Pre-drilled roll 54...(2nd stand) cabinet 55…(Second stand) hole type 60…Web Support Department 62, 63...Flange corresponding parts 65, 66…Arm corresponding parts 68, 69...Joint compatible parts 80(80a, 80b)…Outer guide 90...Roller guide 95...Transport roller 100...Guide support part 103...Lifting mechanism 105...Roller support part 110…Inner guide 112…Lower guide A: Rolled material T...Rolling line (manufacturing equipment)

Claims

1. A manufacturing apparatus for manufacturing a steel sheet pile by hot rolling, The rolling mill includes a roughing mill, an intermediate rolling mill, a finishing rolling mill, and a bending mill that performs finishing rolling and bending of the rolled material continuously, The bending machine includes one or more stands including a first stand, A web restraining guide that restrains an upper surface of the web corresponding portion of the rolled material is provided at least on the upstream side of the first stand of the bending machine, A manufacturing device for steel sheet piles, characterized in that the outer width of the web restraint guide is configured narrower than the inner distance between the left and right flanges of the pre-deformed portion of the rolled material in a steady state at the installation position of the web restraint guide.

2. The steel sheet pile manufacturing apparatus according to claim 1, characterized in that the roll gap directly below the roll of the upper and lower hole type rolls of the bending forming machine in the portion facing the web corresponding portion and the flange corresponding portion of the rolled material is configured to be larger than the thickness of the web corresponding portion and the flange corresponding portion, respectively.

3. The manufacturing apparatus for steel sheet piles according to claim 1 or 2, characterized in that a roller guide is provided as the web restraining guide, and a transport roller is provided at a position facing the roller guide with respect to the rolling line.

4. The manufacturing apparatus for a steel sheet pile according to claim 1 or 2, characterized in that a pair of upper and lower roller guides facing each other on the upper and lower sides of the rolling line are provided as the web restraining guides.

5. The steel sheet pile manufacturing apparatus according to claim 3 , wherein the transport roller is provided at the same position as the roller guide or at a position shifted downstream from the roller guide in a plan view.

6. The steel sheet pile manufacturing apparatus according to claim 4, characterized in that, of the pair of upper and lower roller guides, the lower roller guide is provided at the same position as the upper roller guide or at a position shifted downstream from the upper roller guide in a plan view.

7. The web restraining guide is an inner guide extending in the rolling direction along the inner surface of the rolled material, The steel sheet pile manufacturing device according to claim 1 or 2, characterized in that the cross-sectional shape of the inner guide is configured to change continuously from a cross-sectional shape approximating that of the rolled material after finish rolling to a cross-sectional shape of the rolled material immediately before bending.

8. The manufacturing device for steel sheet piles according to claim 7, further comprising at least one of a lower guide having a substantially flat plate shape extending in the rolling direction along a lower surface of the rolled material or a transport roller.

9. The web restraint guide is provided at a distance L that satisfies the following formula (1) and is located upstream from the roll axis position of the grooved roll of the first stand. The manufacturing device of the steel sheet pile according to any one of claims 1 to 8. L>L1+L2...(1) Here, L1 is the distance between the bending start position and the roll axis position of the grooved roll of the first stand, and L2 is the crop length of the flange corresponding portion of the rolled material.

10. The manufacturing device for a steel sheet pile according to any one of claims 1 to 9, further comprising outer guides extending in the rolling direction on the outer sides of both widthwise ends of the rolled material.

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