[0001]CROSS REFERENCE TO RELATED APPLICATIONS
　This application is based on Japanese Patent Application No. 2017-012994, filed in Japanese on January 27, 2017, and claims priority, the contents of which are incorporated herein.
[0002]The present invention is, for example, hat-shaped steel sheet pile, a method of manufacturing a steel sheet pile in such U-shaped steel sheet piles.
BACKGROUND
[0003]
　Conventionally, the manufacture of steel sheet pile having a joint on both ends such as hat-shape or U shape is done by grooved rolling. The general steps of this caliber rolling method, first the material is heated to a predetermined temperature in a heating furnace, a rough rolling mill having a caliber, known to rolling in order by an intermediate rolling mill and finish rolling mill ing.
[0004]
　According to a general grooved rolling method described above, present, for steel sheet pile products manufactured in Japan, it can be produced from a rectangular cross-section material. Specifically, the second moment per wall width 1m is 1.0 (10 4 cm 4 and / m) at is hat-shaped steel sheet pile product called 10H products, second moment per wall width 1m is 2.5 (10 4 cm 4 / m) at is hat-shaped steel sheet pile product called 25H product is manufactured by general grooved rolling method that is conventionally known.
[0005]
　In the case of producing a sheet pile from a rectangular section material, it is known that various shape defects in the material to be rolled is caused by the rolling process, the solutions have been developed. For example, Patent Document 1, in order to suppress the shape during rolling shaping out chew the end flange of the rolled material occurs, technologies like adding strong pressure under the end portion biting is disclosed. Further, Patent Document 2, a technique for suppressing occurrence of crop by forming a tip material to be rolled is disclosed before rough rolling in the production of shaped steel. In Patent Document 3, in order to reduce the crop, technique which provides preforming portion shape to the end portion of the rolled material is disclosed.
CITATION
Patent Document
[0006]
Patent Document 1: JP 55-50902 Patent Publication
Patent Document 2: JP-A 01-178301 JP-
Patent Document 3: JP 2006-192490 JP
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　In terms of steel sheet piles sectional performance, the thickness of the flange portion is taken thin shape with respect to the web section. When producing a sheet pile from a rectangular cross-section material with grooved rolling method, equal the thickness of the web portion and the flange portion in a rectangular cross-section material stage, the bending rolling phase to form a boundary between the web portion and the flange portion , by the flange portion is shear deformation technique is employed such approach the thickness ratio between the web portion and the flange portion in the thickness ratio of the products. When performing the bending rolling, the ends biting of the material to be rolled, because the material to be rolled central portion (constant region) are undeformed, the shear deformation is difficult to occur, the metal of the arm portions fall on the flange portion , the thickness of the flange portion becomes thick. In the flange thickness becomes thicker, which may lead to the growth of the non-stationary part increases the stretching in the rolling subsequent stage.
[0008]
　Further, since the thickness of the flange portion is thicker at the edge biting, since become different thickness ratio of the web portion and the flange portion, the variation in the shape of the claw portion in the longitudinal direction occur in the longitudinal direction of the rolled material, expansion and a decrease in crop yield is a concern.
　Furthermore, a large case of using the rectangular cross-section material of the slab width, but perform edging rolling before the bending roll is generally, with the bulging deformation by the edging rolling, bending the thickness of the flange portion of the rolling stage there is a possibility that the increase in the becomes more pronounced.
　Incidentally, the above bulging deformation, as shown in FIG. 18, in the edging rolling is a modification bulge occurs in the widthwise direction end portion of the rolled material which is a rectangular cross-section material.
[0009]
　In the technology described in Patent Documents 1-3, when the bending rolling, shear deformation hardly occurs at the edge biting of the material to be rolled, at all for the occurrence of shape defect due to the thickness of the flange portion becomes thicker It has not been recalled. Note that the "end biting of the material to be rolled" in the present specification indicates the rolling direction tip when the rolled material is caught to roll bite a predetermined length of a section from the leading edge end It is set as a part.
[0010]
　In view of the above circumstances, an object of the present invention is the manufacturing of the steel sheet pile, rough rolling step bending rolling phase to suppress shape defect at the end biting of the material to be rolled, the productivity such as improvement and crop reduction in yield It is to provide a method for manufacturing a steel sheet pile which can be improved.
Means for Solving the Problems
[0011]
　To achieve the above object, according to the present invention, by reduction of a rectangular cross-section material and a method of manufacturing a steel sheet pile, have rough rolling step, an intermediate rolling step, a finish rolling step, the crude the rolling mill is rolling step, stretching the thickness center line length of the material, the caliber of performing bending rolling rolling shaped into substantially steel sheet pile cross section the material from rectangular cross-section is provided, the bending rolling in a feature in that for a given section of the end portion biting of the material, reduction rate for the predetermined interval is soft reduction rolling is small, such as rolling than reduction amount for a site other than the predetermined section is performed to method of the steel sheet pile are provided.
[0012]
　The bending rolling is carried out by reverse rolling one pass or multiple passes, the soft reduction rolling may be applied to a one-pass or multiple pass of the reverse rolling.
[0013]
　The bending rolling is performed in multiple passes, rolling by the multiple paths comprises the steps before the flange corresponding portion of the material is not rolling, the steps after the flange corresponding portion of the material is pressure, to be divided, the soft reduction rolling it may be applied to the path of the previous stage of the plurality paths.
[0014]
　Predetermined section of the end portion biting of the material may be set from the end biting of the material longitudinally 0.75m or more sections.
[0015]
　As the material of rectangular cross section, using a material having a plurality of width dimensions, it may be manufactured of steel sheet pile product the same size.
[0016]
　The sheet pile may be a U-shaped steel sheet piles.
[0017]
　The steel sheet pile may be a hat-shaped steel sheet pile.
The invention's effect
[0018]
　According to the present invention, be achieved in the production of steel sheet piles, rough rolling step bending rolling phase to suppress shape defect at the end biting of the material to be rolled, the improvement of productivity such as improvement and crop reduction in yield it is possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
FIG. 1 is a schematic illustration of a rolling line according to the embodiment of the present invention.
FIG. 2 is a schematic illustration of a first grooved grooved shape.
3 is a schematic illustration of the second grooved grooved shape.
4 is a schematic illustration of a third grooved grooved shape.
FIG. 5 is a schematic illustration of a fourth grooved grooved shape.
6 is a schematic illustration of a fifth grooved grooved shape.
7 is a schematic illustration of the hole shape of the sixth grooved.
8 is a schematic illustration of a seventh hole type grooved shape.
9 is a schematic illustration of the hole shape of the eighth hole type.
FIG. 10 is a schematic illustration of a rolling bend in the second caliber.
The distance from the cutting edge biting in [11] bend rolling is a graph showing the relationship between meat splintering of meat splintering portion.
Is a schematic explanatory diagram relating to soft reduction rolling end [12] biting.
Path when FIG. 13 bending is rolling in multiple passes No. Is a graph showing the relationship between the line length and.
Path when FIG. 14 bending is rolling in multiple passes No. And is a graph showing the flange rolling reduction at each pass.
It is a graph according to FIG. 15 Example 1.
16 is a graph according to the second embodiment.
It is a graph according to FIG. 17 Example 3.
Is an explanatory diagram relating to FIG. 18 bulging deformation.
DESCRIPTION OF THE INVENTION
[0020]
　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. In the following description illustrates the case of producing a hat-shaped steel sheet pile as an example of a steel sheet pile product.
[0021]
　Further, in this embodiment, for convenience of explanation, materials having a rectangular cross-section is referred to as material B, the material to be rolled which is approximately hat-shaped cross-sectional shape by rolling a material B is referred to as the material to be rolled A. That is, collectively steel is Tsuzai on the rolling line L at approximately hat-shaped cross section and referred to as the rolled material A, also separately different designation described below for each part of the material to be rolled A and those described Te. Here, a web-enabled unit 3 corresponding to the material to be rolled A is hat-shaped steel sheet pile product web, a flange corresponding portion 4 and 5 are respectively connected to both end portions of the web corresponding section 3, a flange corresponding portion 4 and 5 the arm corresponding portions 6 and 7 which are formed in the respective front end, and a coupling counterpart 8 and 9 are formed on the tip of the arm corresponding portions 6 and 7. Further, the tip of the joint corresponding portions 8,9 pawl corresponding portions 8a, 9a are formed.
[0022]
　Figure 1 is a rolling line L to produce a hat-shaped steel sheet pile is according rolling equipment to the embodiment of the present invention, is an explanatory diagram of a rolling mill provided in the rolling line L. As shown in FIG. 1, the rolling line L, roughing mill (BD) 11, a first intermediate mill (R1) 12, the second intermediate rolling mill (R2) 13, a finishing mill (F) 14 is sequentially It is located. Rolling line L is composed of a plurality of lines L1 ~ L3, and adjacent lines L1 and L2, the line L2 and the line L3 are adjacent. Each of lines L1 ~ L3, and connected in series so as to partially overlap each other, the material to be rolled A from L1 L2 or L2 from L3,, rolling line by moving in parallel in the width direction and it has a configuration that advance the L.
[0023]
　Further, as shown in FIG. 1, the line L1 is disposed roughing mill 11, to the line L2 is disposed first intermediate mill 12, the second intermediate rolling mill line L3 13 and the finishing rolling mill 14 There has been placed. It is possible to perform each rolling put a different material to be rolled A in each line L1 ~ L3, which can be simultaneously performed in parallel rolling of a plurality of the rolled material A on the rolling line L and it has a configuration.
[0024]
　In rolling line L shown in FIG. 1, it is sequentially rolled in the material (material B, the material to be rolled after A) is rough rolling mill 11 to the finishing mill 14 of rectangular cross-section which is heated in a heating furnace not shown, final the hat-shaped steel sheet pile is a product. That is, the rough rolling step, an intermediate rolling step and the final product the final rolling step by performing in this order is prepared against the material B (the material to be rolled A).
[0025]
　In the following, a rough rolling mill 11 arranged on the rolling line L, the first intermediate rolling mill 12, the second intermediate mill 13, finishing mill 14 (hereinafter, roughing mill 11 to the finishing mill 14 more as such the grooved structure provided to describe for short rolling mill) will be briefly described with reference to the step-by-step drawing from the upstream of the rolling line L. Incidentally, the roughing mill 11, the first intermediate rolling mill 12, the second intermediate mill 13, finishing for rolling mill 14 is a common equipment which has been conventionally used, the hole in the following description in this specification gazing the description of the mold structure, the description thereof will not be detailed equipment configuration of each rolling mill.
[0026]
　Also, grooved described below with reference to FIGS. 2-9, which is intended to be provided in each rolling mill of the rough rolling mill 11 to the finishing mill 14, which rolling each grooved described below whether provided the opportunity, usually in consideration of the productivity (efficiency, yield) and workability, and is capable of appropriately changed depending on conditions such as a plant condition and product dimensions. Therefore, in the present embodiment these grooved and referred to as the first grooved K1 ~ eighth hole type K8, each grooved described as may be provided in order from the rolling line L upstream. Note that FIGS. 3-9, the material B to be pressure-molded at the respective grooved for reference, illustrates the shape of the rolled material A by one-dot chain line.
[0027]
　However, the configuration of the first hole-type K1 ~ eighth grooved K8 is according to the present embodiment described below is not limited to the embodiment shown, for example, for increasing or decreasing sequence of the modified caliber of various caliber It can be appropriately changed depending on conditions such as plant condition and product dimensions. In the first grooved K1 ~ eighth grooved K8 described below, preferably carried out in reverse rolling of the rolling shaping multiple paths of the material to be rolled (reversing rolling), the path number may optionally It can be set.
[0028]
　Figure 2 is a schematic illustration of the hole shape of the first hole-type K1. As shown in FIG. 2, the first hole-type K1 is box caliber composed of upper grooved roll 20a and the lower grooved roll 20b, bottom hole of the box caliber has a predetermined tapered . The first hole-type K1, to a tapered shape imparted to the short sides of the end portion in the width direction of the rectangular cross-section material B, and is longitudinally uniform width dimension, of the rectangular cross-sectional shape (not shown) Material B lightly rolling in the width direction in the upright position (state the width direction of the steel sheet pile and the vertical direction) (so-called edging rolling) is performed. Note that impart a tapered shape to the end portion in the width direction of the material B of the rectangular cross-sectional shape, not incorporated suitably chewing the hole shape of the second grooved K2 which will be described later, stably perform the desired pressure, both ends in order to form a nail having a desired meat quantity section. The first hole-type K1 shown in FIG. 2 is a hole type for performing a so-called edging rolling, the first hole-type K1 is referred to as "edging caliber".
[0029]
　3 is a schematic illustration of the grooved shape of the second hole-type K2. As shown in FIG. 3, the second hole-type K2 is an upper grooved rolls 30a as projections rolls, is composed from the lower grooved rolls 30b as grooved roll, by the second grooved K2, the first hole-type reduction is performed on the whole (the rolled material a after) material B of the rectangular cross-sectional shape which is edging rolling in K1. Here, in the pressure in the first hole-type K1 but are upright material B, then material B is rotated 90 ° or 270 °, the width direction of the second in-hole type K2 material B Horizontal pressure while the direction (state in which the width direction of the steel sheet pile and the horizontal direction) is performed, the rolling shaping is carried out in cross-section to an intermediate shape between the rectangular cross-sectional shape substantially hat-shaped cross-section. In this specification, it describes a rolling shaping in the second hole-type K2 as "bending rolling".
[0030]
　Upper grooved roll 30a includes a web facing portion 32 that faces the upper surface of the web corresponding section 3 of the material B, the flange facing portions 34 and 35 opposed to the upper surface of the flange corresponding portion 4 and 5, the arm corresponding portions 6 and 7 and a arm facing portion 37, 38 facing the upper surface.
　On the other hand, the lower grooved roll 30b includes a web facing portion 42 facing the lower surface of the web corresponding section 3 of the material B, the flange facing portion 44, 45 that faces the lower surface of the flange corresponding portion 4 and 5, the arm corresponding section 6 , and it is configured from the arm facing portion 47 that faces the lower surface of 7. Furthermore, the flange opposing portions 44 and 45 is composed of a plurality of portions having different inclination, gradually inclined flange facing portion 44a that connects to the web facing portion 42, and 45a, steep to be connected to the arm facing portions 47 and 48 flange facing portion 44b, and is configured from 45b.
[0031]
　4 is a schematic illustration of the grooved shape of the third grooved K3. As shown in FIG. 4, the third grooved K3 is configured and on grooved rolls 50a as projections roll, from the lower grooved rolls 50b as grooved roll, in the third grooved K3, the second hole-type K2 further reduction is applied to the shaped material B (the rolled material a after) in a generally hat-shaped cross-section cross sectional shape from the intermediate shape (intermediate shape of a rectangular cross-sectional shape substantially hat-shaped cross-sectional shape) consisting such reduction is carried out for the entire material B.
　Here, a substantially hat-shaped cross section, the portion (the web corresponding section 3) corresponding to the web in the material B, the portion corresponding to the flange (flange corresponding portion 4 and 5), the portion corresponding to the arm (arm handling unit 6, 7) each boundary refers to the cross-sectional shape which is pressure to the extent that clear, does not necessarily indicate a cross-sectional shape which is formed to fine shape such as joint shape.
[0032]
　Upper grooved roll 50a includes a web facing portion 52 that faces the upper surface of the web corresponding section 3 of the material B, the flange facing portion 55 that faces the upper surface of the flange corresponding portion 4 and 5, the arm corresponding portions 6 and 7 and a arm facing portions 57 and 58 opposed to the upper surface.
　The lower grooved roll 50b includes a web facing portion 62 that faces the lower surface of the web corresponding section 3 of the material B, the flange facing portion 64, 65 that faces the lower surface of the flange corresponding portion 4 and 5, the arm corresponding section 6 , and it is configured from the arm facing portion 67 that faces the lower surface of 7.
[0033]
　Figure 5 is a schematic illustration of the grooved shape of the fourth hole-type K4. As shown in FIG. 5, a fourth grooved K4 is configured from the lower grooved rolls 70b as grooved roll 70a and grooved roll over as projection roll, claw corresponding portion is formed by the fourth grooved K4 together, the thickness reduction and molding to the entire material to be rolled a (thickness elongation rolling) is performed, are more hat-shaped steel sheet pile near the product shape.
[0034]
　Figure 6 is a schematic illustration of the hole shape of the fifth hole type K5. As shown in FIG. 6, the fifth grooved K5 is composed from the lower grooved rolls 80b as grooved roll 80a and grooved roll over as projection roll, the whole material to be rolled A to this fifth grooved K5 the thickness reduction and molding is performed Te. Specifically, pawl corresponding portion 8a, the height of 9a (in the figure, the vertical height h1) to adjust to two claw corresponding portion 8a, a claw height molding to align the heights of 9a, to be rolled the thickness reduction of the entire timber a are performed simultaneously. Incidentally, the pawl corresponding portion 8a, as in the fifth hole type K5, molded to align the height of the 9a is referred to as nail molding process, the caliber of performing pawl molding process is referred to as a claw forming pass.
[0035]
　Figure 7 is a schematic illustration of the hole shape of the sixth grooved K6. As shown in FIG. 7, a sixth grooved K6 consists lower grooved rolls 90b as grooved roll 90a and grooved roll over as projection roll, the whole material to be rolled A to this sixth grooved K6 the thickness reduction and molding (thickness elongation rolling) is carried out Te.
[0036]
　Figure 8 is a schematic illustration of the hole shape of the seventh hole type K7. As shown in FIG. 8, the seventh hole type K7 consists lower grooved roll 100b as grooved roll 100a and the groove roll over as projection roll, the whole material to be rolled A to this seventh hole type K7 the thickness reduction and molding is performed Te, in particular, the claw corresponding portions 8a, 9a of the height (in the figure, the vertical height h2) to adjust to two claw corresponding portion 8a, nail height to align the height of 9a molding is carried out is. However, the seventh hole type K7, the thickness reduction rate compared with the sixth grooved K6 performing thickness reduction of the overall material to be rolled A positively small.
[0037]
　Figure 9 is a schematic illustration of the hole shape of the eighth hole type K8. As shown in FIG. 9, an eighth hole type K8 is configured from the lower grooved roll 110b as grooved roll 110a and the groove roll over as projection roll, in the eighth hole type K8, the material to be rolled A joint bending and shaping of the corresponding part 8, 9, the rolled material a total of shaping by mild rolling is performed. Specifically, pawl corresponding portion 8a, is joint forming to bend the entire joint corresponding portions 8,9 such that the product of the joint shapes including 9a is performed. Thus, in the eighth hole type K8, so that the material to be rolled A to the shape of the hat-shaped steel sheet pile product is molded. Incidentally, the joint corresponding portions 8,9 formed for the grooved bend the whole like the eighth hole type K8 is referred to as a finishing grooved.
[0038]
　It has been described above hole shape and function of the first hole-type K1-eighth caliber K8 with reference to FIGS. 2-9. As described above, the hole-type rolling method is rough rolling step of the hat-shaped steel sheet pile, the intermediate rolling step, the finishing consists rolling process, for example, rough rolling step and the first grooved K1 ~ caliber up to the 7-hole type K7 intermediate rolling step is carried out sequentially, the finish rolling step is performed in the eighth hole type K8. Here, the hole shape of the fourth hole-type K4 ~ eighth grooved K8 are both substantially hat-shaped cross section, are provided in a shape close to a product shape as it goes to the subsequent caliber. That is, the shape of the eighth hole type K8 that finish rolling is the final step is carried out, a substantially hat-shaped steel sheet pile product shape.
[0039]
　In this embodiment, the rolling line L, roughing mill (BD) 11, a first intermediate mill (R1) 12, the second intermediate rolling mill (R2) 13, finishing mill (F) 14 is Although assumed to be arranged in this order, the first hole-type K1 ~ eighth grooved K8 are provided distributed in any configuration on each rolling mill. As an example, the first hole-type K1 ~ third grooved K3 is provided on the roughing mill 11, the fourth hole-type K4 and the fifth grooved K5 is provided in the first intermediate rolling mill 12, the second intermediate rolling sixth grooved K6 and seventh hole type K7 are provided on the machine 13, the eighth hole type K8 are mentioned configuration such provided finishing mill 14. However, the caliber configurations are not limited to such a configuration of the present invention.
[0040]
　The present inventors have Conventionally, in building process in the rough rolling step of said second grooved K2 for shaping a generally hat-shaped cross-sectional shape from the material B of the rectangular cross-sectional shape, the following 1) to 3) described It found that problems such as there was conducted an extensive study for techniques to eliminate the problem.
1) When rolling shaping a rectangular cross-section material (material B) in the second hole-type K2, the thickness of the shaped material before B is the thickness equal the web portion and the flange portion, the thickness ratio between the web portion and the flange portion rolled shaped like close to product thickness ratio is made mainly of shear deformation. At this time, since the vicinity of the center of the material to be rolled longitudinally (so-called constant region) is undeformed, hardly causes shear deformation in the end portions biting, the thickness of the flange portion becomes thicker. By the thickness of the flange portion becomes thicker, the higher the flange stretching in the subsequent rolling, the growth of the non-stationary part (so-called crop) is concerned.
2) Bending thickness of the flange portion is thicker in the rolling, in order to become the longitudinal web portions and the thickness ratio is different, such properties of the flange portion of the material to be rolled, the claw portion in the longitudinal direction of the material to be rolled (claw corresponding portions 8a, 9a) there is a possibility that variations in the shape of occurs.
3) as a rectangular section material B, and using a large material than conventional materials width (so-called slab width), for edging rolling (rolling of the first grooved K1 described above) at the rolled material is bulging deformation, bending shear deformation during rolling is further inhibited, defective shapes such thickness of the flange portion becomes thick to lead to a more pronounced. That is, it is difficult to use a large materials of the material width than conventional material dimensioned to be allowed is limited.
[0041]
　Here, the problems 1) to 3) will be described with reference to the drawings. Figure 10 is a schematic illustration of a rolling bend in the second hole-type K2, it illustrates (a) ~ (d) the the process of bending rolling performed in multiple passes in order.
　As shown in FIG. 10 (a), the upper and lower surfaces of the material B which is edging rolling in the first hole-type K1 to the upper grooved roll 30a and the lower grooved roll 30b abuts. Then, FIG. 10 (b), (c) , the rolling bending as shown in (d) to proceed. At that time, a step of the flange corresponding portion 4 and 5 shown in FIG. 10 (b) is not under pressure (front-pass), the step of the flange corresponding portion 4 and 5 shown in FIG. 10 (c) ~ (d) is pressure (later stage path) and is present.
[0042]
　The bending rolling, the thickness center line length of the O of the material B shown by a chain line O in FIG. 10 (hereinafter, simply described as line length) is a rolling stretch, in principle, FIG. 10 (a) ~ (d toward the downstream), the line length is found to grow. Figure 13 is a path in the case of performing bending rolling in multiple paths No. And is a graph showing the relationship between the line length. As shown in FIG. 13, the bending roll, is implemented rolled as line length is extended in the first few passes (for example, 1 to 5 passes), the subsequent passes has been found that line length does not substantially vary. In such a case, hardly undergoes phenomenon flange thickness becomes thick for shear deformation described above problem 1) is expressed especially prominently in rolling line length is extended. This is because the rolling line length is extended is because the shape difference between the vicinity of the center of the material to be rolled longitudinally (so-called constant regions) which is an end portion bite undeformed large.
[0043]
　Further, FIG. 14, the path when performing bending rolling in multiple paths No. And is a graph showing the flange rolling reduction at each pass. As shown in FIG. 14, the flange rolling reduction of 0 (not pressure) stage (for example, 1 to 2-pass) and the flange rolling reduction is a positive value (being pressure) stage (e.g. 3-pass or later) Existing. In such a case, hardly undergoes phenomenon flange thickness becomes thick for shear deformation described above problem 1), the flange rolling reduction is expressed especially prominently in step is 0. This is the fact that the flange rolling reduction begins is, it indicates that rolling extending the line length (bending) is almost finished, after initiation flange pressure because has a rolling thickness reduction principal. Incidentally, the flange pressure is initiated, the growth of the non-stationary part (flange prior amount) when Shirinuke of the material to be rolled becomes dominant.
[0044]
　Rolling shaping of the material to be rolled bending caused by the rolling is performed in the step shown in FIG. 10 is known to be mainly shear deformation, shear deformation to the constant part is undeformed at the end biting less likely, the metal of the arm corresponding portions 6 and 7 is a drop in the flange corresponding portions 4 and 5, the thickness of the flange corresponding parts 4 and 5 becomes thicker. Accordingly, the side surface of the arm corresponding portions 6 and 7, so that the portion 6a splintering meat as shown in FIG. 10 (d), 7a are formed. When such process is performed to the pinching section, the 1) problem as described in 1-3) may occur.
[0045]
　Figure 11 is a graph showing the distance from the cutting edge biting in bending rolling, the above-mentioned meat splintering portion 6a, the relationship between meat splintering of 7a. Note that FIG. 11 is a data for the bending roll in the case of rolling shaping the so-called 25H products, meat splintering amount was measured with a widthwise length of the material to be rolled. Further, in FIG. 11, shown for the range distance is 0 ~ 5 m from the end biting in the case of the rolled material length about 10 m, WS, DS is represent respectively the widthwise end of the rolled material (Material B) there.
[0046]
　As shown in FIG. 11, the amount of splintering meat in accordance with the distance from the biting cutting edge is varied, the claw portion in the longitudinal direction of the rolled material as described in 2) above (claw corresponding portions 8a, 9a) it can be seen that the variation of the shape occurs. That is, the expansion of the reduction or crop yield due to variations of the claw portion shape is concern can be seen from the data in Figure 11.
[0047]
　Above, 10, 11 the problem 1 described above with reference to) light of 1-3), the present inventors have considered that the shape defect is prominent at the end biting of the material to be rolled, in one part pass or all pass during rolling bend, the roll gap of the upper and lower grooved roll open compared to the roll gap against stationary unit in a suitable timing, only the end portion biting with soft reduction rolling the occurrence of shape defect in biting end was devised a technique for suppressing.
[0048]
　Figure 12 is a schematic explanatory diagram relating to soft reduction rolling end biting. Specifically, the second hole-type K2 (vertical grooved roll 30a, 30b) to open the roll gap in the rolling shaping in an explanatory diagram for performing soft reduction rolling to end biting, from the side it is a schematic side view. Since the description for FIG. 12, the rolling shaping the material before B (left side in the drawing) in any path, immediately after the rolling shaping initiation at the path and (in the figure the center), after the rolling shaping completion in the path It is illustrated (in the right hand side of the drawing).
[0049]
　As shown in FIG. 12, the second hole-type K2, at the time of molding the start left open the roll gap than the roll gap at the time of the constant region rolling, by a predetermined interval P of the end portion biting material B is grooved roll after passing through the diaphragm a roll gap, it is preferable to perform rolling shaping of the steady portion.
　In bending rolled This is carried out as, reduction rate in comparison with the constant region for a given period P of the end portion biting is low state (i.e., soft reduction) rolling is performed bending. Thus, the problem 1) can be suppressed to 3) the occurrence of shape defects on the biting end as described as.
[0050]
　Here bending described soft reduction during rolling may be applied to all paths when bending rolling is performed in multiple passes, it may be applied to some path. Moreover, the reversible rolling (reverse rolling) Sometimes, by applying the soft reduction rolling to end biting of the material to be rolled in each of the path, it is possible to suppress the shape defect. A specific example of a pass schedule in applying soft reduction rolling will be described later in the Examples.
[0051]
　Further, as the predetermined interval P, it is preferable that the range of edge biting except to the extent so-called constant regions in the material to be rolled longitudinally that range can be arbitrarily set as appropriate. Still later in the Examples for specific examples of the predetermined interval P.
[0052]
　The above in order to implement soft reduction rolling as described, in a rolling mill in which the second hole-type K2 is provided, it is preferable to adopt a configuration having a mechanism for changing the roll gap of the grooved roll. As the mechanism, hydraulic pressure mechanism and the like for example.
[0053]
　Described above, according to the method of manufacturing a steel sheet pile in accordance with the present embodiment, for a given interval P end biting is performed bending rolled state quantity reduction is small compared to other sections. Thus, by suppressing the generation of shape defect at the edge biting, it is possible to improve the productivity such as improvement and crop reduction in yield.
[0054]
　Further, suppressing the thickness ratio between the web portion and the flange portion in the longitudinal direction of the rolled material becomes different such properties, the claw portion in the longitudinal direction of the rolled material (claw corresponding portions 8a, 9a) of solve the problem of variations in shape, it can be made uniform claw portion shape.
[0055]
　Furthermore, with large materials of the material width (so-called slab width) than conventional, even the material to be rolled is bulging deformation at the time of edging rolling, difficult to shear deformation during bending rolling inhibition, the thickness of the flange portion is thicker the shape defect is suppressed such, it becomes possible than the conventional use of large materials of the material width, it is achieved expansion of the material dimensions allowed. For example, even when producing the same steel sheet pile product, it is possible to manufacture using a rectangular cross-section material having a plurality of kinds of widths.
[0056]
　Incidentally, a technique for applying soft reduction rolling in bending rolling described above, may be applied to all paths when bending rolling is performed in multiple passes, may be applied to some path. Bending when to reverse the material B in the rolling of a plurality of paths, by applying the soft reduction rolling to biting edges of the substrate B in each of the path, the longitudinal ends of the material B of the defective shape it is possible to suppress.
[0057]
　Having described an example of an embodiment of the present invention, the present invention is not limited to the illustrated form. Those skilled in the art within the scope of the spirit as set forth in the appended claims, it is intended to cover various modifications and changes naturally fall within the technical scope of the present invention also for their things to be understood.
[0058]
　For example, in the embodiment described above, are illustrated, described as an example the case of producing a hat-shaped steel sheet pile product, the scope of the present invention is not limited thereto. Specifically, in various production processes of steel sheet pile product manufactured using the rectangular cross-section material, by applying the present invention, it is possible to suppress the shape defect of the end portion biting. However, hat-shaped steel sheet pile is a steel sheet pile, characterized in large section structure, its on features, the height is high in shape after the second grooved rolling is rolling bent substantially steel sheet pile cross-sectional shape of the general deformation amount of line length as compared with the steel sheet pile is large. Therefore, the present technique is particularly useful in the manufacture of the hat-shaped steel sheet pile.
[0059]
　In the above embodiment, FIG. 3 in the to 10 and the protrusion roll of a series of grooved columns and upper grooved roll, configuration of arranging the grooved roll as the lower grooved roll, hat-shaped steel sheet pile in a so-called U posture rolling when performing rolling illustrated-described. However, for some or all of such series of holes type column, the protrusion roll and lower grooved roll, configuration of arranging the grooved roll as the upper grooved rolls, the rolling of the hat-shaped steel sheet pile in so-called reverse U posture rolling it may be carried out.
Example
[0060]
　(Example 1)
　As Example 1 of the present invention, the second moment per wall width 1m is 2.5 (10 4 cm 4 / m) caliber rolling method a hat-shaped steel sheet pile so-called 25H product is by the time of manufacture, when applied during rolling bending technique (soft reduction rolling at a predetermined interval) according to the present invention described in the above embodiment, the interval of applying the soft reduction rolling (the predetermined period P) and length were measured relationship unsteady director Sato at the end biting bending after rolling. Incidentally, the rolling pass schedule bent according to Example 1 are those shown in Table 1 below.
[0061]
[Table 1]

[0062]
　Figure 15 is a graph according to the first embodiment, and shows the length of a section to apply soft reduction rolling, the unsteady director Sato relationship with end biting bending after rolling. As shown in FIG. 15, when the above 0.75m application section of soft reduction rolling, unsteady portion length of the second grooved K2 after rolling is suppressed below the lower level of about 175mm. On the other hand, when it is less than 0.75m application section of soft reduction rolling increases the unsteady portion length after the second grooved K2 rolling, the interval is larger or more about the 0.5 m 200 mm, it can be seen that the length of shape defect occurs in the end portion biting is increased. From the measurement result, by setting the material to be rolled longitudinally from the biting edge over 0.75m interval as an application section soft reduction rolling, it is understood that it is possible to suppress effectively unsteady portion length.
[0063]
　(Example 2)
　As Example 2 of the present invention, the second moment per wall width 1m is 2.5 (10 4 cm 4 / m) caliber rolling method a hat-shaped steel sheet pile so-called 25H product is light of the time of manufacture, the flange prior amount to bending after rolling the web in the case of carrying out the rolling bending without applying the present technique, in the technique according to the present invention (the predetermined interval (1m from biting end) by a flange prior amount to bending after rolling the web in the case of applying the reduction rolling) were measured compared. Incidentally, rolling pass schedule bent according to the second embodiment are those shown in Table 2 below, the level 1 in the table is prior art, level 2 is the present technique, when applying the present technique (application of biting soft reduction) in one pass and two-pass bending rolled soft reduction rolling was performed. Further, in the measurement in Example 2, a rectangular cross-section material width (slab width) was varied from 980mm to 1150 mm, it was measured flange prior amount for each case.
　Here, the flange prior amount, after bending rolling, which indicates the length stretched many flange portion than the web portion in the material to be rolled longitudinally, as the flange prior amount increases, the non-stationary part (shape It leads to an increase in the bad part).
[0064]
[Table 2]

[0065]
　Figure 16 is a graph according to the second embodiment, the rectangular cross-section material width (slab width) and 1150mm from 980 mm, showing a flange prior amount when subjected to bending rolling in Table 2 pass schedule in each case graph it is. As shown in FIG. 16, even in the case of using a material having substantially the same slab width, when applying the present technique, it can be seen that reduction of the flange prior amount after bending rolling is achieved. For example, when a material of the slab width 1010 mm, and, in either case of using the material of the slab width 1070mm also can be seen that can reduce about 20% of the flange prior quantity length.
[0066]
　Further, from FIG. 16, using the material of the slab width 980 mm, and the flange preceding volume, when the bending rolled by conventional techniques, using a material of the slab width 1010 mm, in the case where the applied bending rolled present technique it can be seen that the flange prior amount becomes approximately the same amount (about 80 mm). Similarly, using the material of the slab width 1020 mm, the flange preceding volume, when the bending roll by the prior art flange prior amount when using the material of the slab width 1070 mm, and the bending roll by applying the present technique it can be seen that nearly the same amount (about 110 mm). That is, by applying the present technique, without growing the unsteady portions, it is possible to use a large materials of the material width than conventional, it was found that attained expansion of material dimensioned to be acceptable.
[0067]
　(Example 3)
　Example 3 of the present invention, the second moment per wall width 1m is 2.5 (10 4 cm 4 / m) caliber rolling method a hat-shaped steel sheet pile so-called 25H product is applied in manufacturing, a claw height and claw hole width after nail molding step in the case of carrying out the rolling bending without applying the present technique, the technique according to the present invention (soft reduction rolling at a predetermined interval) by a claw height and claw hole width after nail molding step in the case of, was measured compared.
[0068]
　Figure 17 is a graph according to Embodiment 3, (a) is applied relationship between the distance and the pawl height of the fifth grooved K5 after rolling from biting the edge of the prior art, the (b) is present technique relationship between the distance from the edge biting in the case where the pawl height of the fifth grooved K5 after rolling, the (c) after the distance and the eighth hole type K8 rolling from biting the edge of the prior art (product) relationship between the pawl hole width is a graph showing the relationship between the pawl hole width (d) of after the distance and the eighth hole type K8 rolling from the end biting in the case of applying the present invention (product). As the distance from the edge biting shown in the graph of FIG. 17 (a) ~ (d), illustrates the extent distance of 0 ~ 10 m from the biting-art case of material to be rolled overall length 35m there.
[0069]
　Compared 17 and (a) and (b), conventionally whereas the variation of the claw height was about 4mm at a later stage the fifth grooved K5 rolling, by applying the present technique, it can be seen that the variation in the nail height is improved to about 1 mm.
　In comparison Figure 17 (c) and (d), while the conventional variation of the nail hole width of the product was about 2 mm, by applying the present technique, the nail hole width of product it is understood that variations is improved to about 0.8 mm.
　That is, by applying the present technique, it can be seen that the longitudinal variations in shape of the claw portion after the claws forming step (claw corresponding portion) is suppressed.
Industrial Applicability
[0070]
　The present invention is applicable for example hat-shaped steel sheet pile, the method for producing a steel sheet pile in such U-shaped steel sheet piles.
DESCRIPTION OF SYMBOLS
[0071]
　3 ... web corresponding section
　4, 5 ... flange corresponding portion
　6,7 ... arm corresponding portions
　8,9 ... joint corresponding portion
　8a, 9a ... pawl corresponding portion
　11 ... roughing mill
　12 ... first intermediate mill
　13 ... second intermediate mill
　14 ... finishing mill
　32, 42 ... (second grooved) web facing portion
　(of the second grooved) 34,35,44,45 ... flange facing portions
　37,38,47,48 ... (second hole-type) arm facing portions
　52 and 62 ... (the third grooved) web facing portions
　54,55,64,65 ... (the third grooved) flange facing portions
　57,58,67,68 ... (3 hole-type) arm facing section
　a ... the rolled material
　B ... material
　O ... (material) thickness of the center line
　K1-K8 ... first grooved to eighth hole type
　L (L1-L3) ... rolling line

WE CLAIM

The rectangular cross-section material by rolling A method of manufacturing a steel sheet pile,
rough rolling step, an intermediate rolling step, a finish rolling step,
the rolling mill to perform the rough rolling process, the thickness of the material extending the center line length, the material caliber performing bending rolled shaped rolled into a substantially steel sheet pile cross-section from a rectangular cross section is provided,
in the bending rolling, for a given section of the end portion biting of the material Te, reduction rate, characterized in that the soft reduction rolling with a small as rolling than reduction amount for a site other than the predetermined section is performed for the predetermined period, the production method of the steel sheet pile.
[Requested item 2]
The bending rolling is carried out by reverse rolling one pass or multiple passes,
the soft reduction rolling, characterized in that it is applied in one pass or multiple passes of the reverse rolling, the steel according to claim 1 method of manufacturing a sheet pile.
[Requested item 3]
The bending rolling is performed in multiple passes,
rolling by the multiple paths comprises the steps before the flange corresponding portion of the material is not rolling, the steps after the flange corresponding portion of the material is pressure, to be divided,
the soft reduction rolling It is characterized in that it is applied to the path of the previous stage of the plurality paths, method for producing a steel sheet pile according to claim 1.
[Requested item 4]
Predetermined section of the end portion biting of the material is characterized in that it is set to the material longitudinally from biting the edge of the above 0.75m section, Steel according to any one of claims 1 to 3 method of manufacturing a sheet pile.
[Requested item 5]
As the material of rectangular cross section, using a material having a plurality of width dimensions, characterized in that the production of steel sheet pile product the same size, the method of manufacturing the steel sheet pile according to any one of claims 1 to 4, .
[Requested item 6]
Characterized in that the sheet piles are U-shaped steel sheet pile, the production method of the steel sheet pile according to any one of claims 1 to 5.
[Requested item 7]
Characterized in that the steel sheet pile is a hat-shaped steel sheet pile, the production method of the steel sheet pile according to any one of claims 1 to 5.