JP6828722B2 - Hat-shaped steel sheet pile, manufacturing method of hat-shaped steel sheet pile, and its manufacturing equipment - Google Patents

Hat-shaped steel sheet pile, manufacturing method of hat-shaped steel sheet pile, and its manufacturing equipment Download PDF

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JP6828722B2
JP6828722B2 JP2018143643A JP2018143643A JP6828722B2 JP 6828722 B2 JP6828722 B2 JP 6828722B2 JP 2018143643 A JP2018143643 A JP 2018143643A JP 2018143643 A JP2018143643 A JP 2018143643A JP 6828722 B2 JP6828722 B2 JP 6828722B2
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steel sheet
shaped steel
sheet pile
joint portion
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JP2019038035A (en
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駒城　倫哉
倫哉 駒城
幸宏 帆足
幸宏 帆足
一郎 大原
一郎 大原
啓之 福田
啓之 福田
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JFE Steel Corp
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Description

本発明は、ハット形鋼矢板、その製造方法および製造設備に関するものであり、特に鋸断後において寸法精度が優れる端部が得られるハット形鋼矢板、ハット形鋼矢板の製造方法、およびその製造設備に関する。 The present invention relates to a hat-shaped steel sheet pile, a method for manufacturing the same, and a manufacturing facility, and particularly a hat-shaped steel sheet pile, a method for manufacturing the hat-shaped steel sheet pile, and a manufacturing method thereof, which can obtain an end portion having excellent dimensional accuracy after sawing. Regarding equipment.

熱間圧延によって製造される形鋼は、断面各部の厚み差や冷却条件差による温度差によって、冷却後に反りが発生したり、熱間圧延後、熱間鋸断される場合は、温度差により断面内に生じる残留応力が熱間鋸断部で開放されることで端部変形が発生する。
特許文献１は、形鋼の拘束冷却方法に関し、熱間圧延中に生じる断面内温度不均一に起因する反りを解消するため、拘束冷却開始時の形鋼温度にもとづいて、冷却中の形鋼温度や変態点率等を推測し、これらを基に反りが生じないように拘束冷却条件を選定することが記載されている。
形鋼に端部変形が生じた場合は、鋸断後において端部形状の矯正作業が必要となるが、レベラー矯正では、長手方向の端部には、圧下を加えることができないため修正が困難で、一方、プレス矯正を用いると矯正は可能であるが、生産効率が低下する。 Shaped steel produced by hot rolling is warped after cooling due to the difference in thickness of each part of the cross section and the temperature difference due to the difference in cooling conditions, or if it is hot sawed after hot rolling, it is due to the temperature difference. End deformation occurs when the residual stress generated in the cross section is released at the hot sawn portion.
Patent Document 1 relates to a method for constraining and cooling a shaped steel, and in order to eliminate warpage caused by uneven temperature in a cross section that occurs during hot rolling, the shaped steel being cooled is based on the shape steel temperature at the start of restraint cooling. It is described that the temperature, transformation point rate, etc. are estimated, and the restraint cooling conditions are selected based on these so that warpage does not occur.
If the shaped steel is deformed at the end, it is necessary to correct the shape of the end after sawing, but with leveler straightening, it is difficult to correct it because it is not possible to apply reduction to the end in the longitudinal direction. On the other hand, if press straightening is used, straightening is possible, but the production efficiency is lowered.

特許文献２は、圧延ラインにおける鋼矢板等の端部形状精整法に関し、フランジ部の先端に継手部を有するＵ形鋼矢板を圧延した際、圧延後の冷却過程においてウェブやフランジの厚みの相違によりフランジがウェブより早く冷却され、また、鋸断により熱応力が開放されることなどにより形状不良を生じやすい長手方向の端部を、仕上げ圧延前の表面温度を特定範囲とし、鋸断後にフランジ付け根部（コーナ部）に冷却を施すことにより、寸法公差内とすることが記載されている。
特許文献３は、形鋼の端部形状制御方法に関し、熱間鋸断直近のフランジ又はウェブの外表面の温度を測定し、当該温度と端曲がりの相関実績から求まる、端曲がりが生じない冷却基準温度となるように鋸断中および／または鋸断後において強制冷却を行うことが記載されている。 Patent Document 2 relates to a method for adjusting the shape of an end of a steel sheet pile or the like in a rolling line. When a U-shaped steel sheet pile having a joint at the tip of a flange is rolled, the thickness of the web or flange is increased in the cooling process after rolling. Due to the difference, the flange is cooled faster than the web, and the end in the longitudinal direction, which is prone to shape defects due to the release of thermal stress by sawing, has a specific range of surface temperature before finish rolling, and after sawing. It is stated that the dimensional tolerance is achieved by cooling the base of the flange (corner).
Patent Document 3 relates to a method for controlling the shape of an end portion of a shaped steel, in which the temperature of the outer surface of the flange or web closest to the hot saw is measured, and cooling without edge bending, which is obtained from the correlation record between the temperature and the edge bend. It is stated that forced cooling is performed during and / or after sawing to reach the reference temperature.

特開平２−１５８１６号公報Japanese Unexamined Patent Publication No. 2-15816 特開昭５３−８１４６４号公報Japanese Unexamined Patent Publication No. 53-81464 特開昭５５−１３９１０５号公報JP-A-55-139105

ところで，図１１（ａ）にその断面形状の全体を示すように，ウェブ部２と、フランジ部３と、継手部４と、フランジ部３と継手部４との間に腕部５とを有するハット形状のハット形鋼矢板１の場合、腕部５を有する分、Ｕ形鋼矢板よりも断面寸法が大きくなる。このためハット形鋼矢板１では，圧延仕上がり時の断面内各部位の温度の不均一に起因して冷却後に生じる残留応力が断面形状に与える影響が大きく、特に圧延後に製品長さに鋸断（ハット形鋼矢板１を幅方向に鋸断）したとき、残留応力による端部の変形がより大きくなり、場合によっては寸法公差を外れる場合が生じる。図１１（ｂ）には、ハット形鋼矢板１の継手部４を拡大した状態、図１１（ｃ）には、ハット形鋼矢板１の継手部４同士が嵌合する状態が示されている。 By the way, as shown in FIG. 11A as a whole of the cross-sectional shape, the web portion 2, the flange portion 3, the joint portion 4, and the arm portion 5 are provided between the flange portion 3 and the joint portion 4. In the case of the hat-shaped steel sheet pile 1, the cross-sectional dimension is larger than that of the U-shaped steel sheet pile because the arm portion 5 is provided. For this reason, in the hat-shaped steel sheet pile 1, the residual stress generated after cooling due to the non-uniformity of the temperature of each part in the cross section at the time of rolling finish has a large influence on the cross-sectional shape, and especially after rolling, it is sawn to the product length ( When the hat-shaped steel sheet pile 1 is sawn in the width direction), the deformation of the end portion due to the residual stress becomes larger, and in some cases, the dimensional tolerance may be exceeded. FIG. 11B shows an enlarged state of the joint portion 4 of the hat-shaped steel sheet pile 1, and FIG. 11C shows a state in which the joint portions 4 of the hat-shaped steel sheet pile 1 are fitted to each other. ..

図１２はハット形鋼矢板１の端部に生じる変形の模式図であり，左右の継手部４が外側に広がりつつ上にも反るいわゆる「ラッパ変形」（図１２（ａ）参照）、逆に、左右の継手部４が内側に狭まりつつ下にも反る「逆ラッパ変形」（図１２（ｂ）参照）、あるいは、左右の継手部４の一方が「ラッパ変形」、他方が「逆ラッパ変形」という形状に変形する場合がある。 FIG. 12 is a schematic view of deformation occurring at the end of the hat-shaped steel sheet pile 1, and is a so-called “trumpet deformation” in which the left and right joint portions 4 spread outward and warp upward (see FIG. 12 (a)). In addition, "reverse trumpet deformation" in which the left and right joints 4 narrow inward and warp downward (see FIG. 12B), or one of the left and right joints 4 is "trumpet deformation" and the other is "reverse". It may be transformed into a shape called "trumpet deformation".

特許文献１に記載された技術は、鋼矢板の上下方向の反りを防止しようとする技術であり、製品端部のラッパ変形を防止するものではない。また、拘束冷却を行うためには、非常に大きな設備投資が必要となる。
特許文献２に記載された技術は、圧延後の熱間鋸断時にＵ形鋼矢板のフランジ付け根部を冷却する技術であり、そのままハット形鋼矢板に適用できる技術ではない。特に，ハット形鋼矢板はＵ形鋼矢板よりも複雑な形状でサイズ（全幅寸法）も大きいため、圧延パス数が多くなり熱間鋸断時の温度が非常に低くなる。このため，この技術では効果が見込めない。また、鋼矢板は熱間鋸断以外に冷間で所定の長さに鋸断する場合も多いが、この技術は冷間鋸断された鋼矢板の鋸断部には全く対応ができない。 The technique described in Patent Document 1 is a technique for preventing the steel sheet pile from warping in the vertical direction, and does not prevent the trumpet deformation at the end of the product. In addition, a very large capital investment is required to perform restraint cooling.
The technique described in Patent Document 2 is a technique for cooling the flange base portion of the U-shaped steel sheet pile during hot sawing after rolling, and is not a technique that can be directly applied to the hat-shaped steel sheet pile. In particular, since the hat-shaped steel sheet pile has a more complicated shape and a larger size (total width dimension) than the U-shaped steel sheet pile, the number of rolling passes increases and the temperature during hot sawing becomes extremely low. Therefore, this technology cannot be expected to be effective. In addition to hot sawing, steel sheet piles are often sawed to a predetermined length in the cold, but this technique cannot handle the sawed portion of the cold sawed steel sheet pile.

特許文献３に記載された技術は、熱間鋸断時の鋼矢板の内外面の温度差によって発生するとされる端部の変形を防止しようとする技術であり、内外面の温度差ではなく、各部位の温度差によって発生するハット形鋼矢板の端部変形に適用できるものではない。また、特許文献２と同様に、鋼矢板は熱間鋸断以外に冷間で所定の長さに鋸断する場合も多いが、この技術は冷間鋸断された鋼矢板の鋸断部には全く対応ができない。 The technique described in Patent Document 3 is a technique for preventing deformation of the end portion, which is said to be caused by a temperature difference between the inner and outer surfaces of the steel sheet pile during hot sawing, and is not a temperature difference between the inner and outer surfaces. It cannot be applied to the end deformation of the hat-shaped steel sheet pile caused by the temperature difference of each part. Further, as in Patent Document 2, the steel sheet pile is often sawed to a predetermined length in the cold in addition to the hot sawing, but this technique is applied to the sawed portion of the cold sawed steel sheet pile. Can't handle it at all.

そこで、本発明は、このような問題を鑑みてなされたものであり、ハット形鋼矢板に関し、圧延後の熱間、冷間を問わず所定の製品長さに切断されたハット形鋼矢板の端部に「ラッパ変形」「逆ラッパ変形」という形状不良がない、良好な形状のハット形鋼矢板を提供すること、およびそれを安価に実現するハット形鋼矢板の製造方法を提供すること、さらには、上記形状不良を抑制するための製造条件を評価可能なハット形鋼矢板の製造設備を提供すること、また、さらには、この評価にもとづき上記形状不良を抑制可能なハット形鋼矢板の製造設備を提供することを目的とする。 Therefore, the present invention has been made in view of such a problem. Regarding the hat-shaped steel sheet pile, the hat-shaped steel sheet pile cut to a predetermined product length regardless of whether it is hot or cold after rolling. To provide a hat-shaped steel sheet pile having a good shape without shape defects such as "trumpet deformation" and "reverse trumpet deformation" at the end, and to provide a method for manufacturing a hat-shaped steel sheet pile that realizes it at low cost. Furthermore, it is possible to provide a manufacturing facility for a hat-shaped steel sheet pile capable of evaluating the manufacturing conditions for suppressing the shape defect, and further, a hat-shaped steel sheet pile capable of suppressing the shape defect based on this evaluation. The purpose is to provide manufacturing equipment.

本発明の一態様によれば、ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板であり、継手部ないし腕部の残留応力最大値σgとフランジ部の残留応力最小値σfとの差である残留応力差Δσ（＝σg−σf）が0MPa以上60MPa以下であることを特徴とするハット形鋼矢板が提供される。 According to one aspect of the present invention, it is a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion and a joint portion, and has a maximum residual stress value σg of the joint portion or the arm portion and a minimum residual stress value of the flange portion. Provided is a hat-shaped steel sheet pile characterized in that the residual stress difference Δσ (= σg−σf), which is the difference from σf, is 0 MPa or more and 60 MPa or less.

本発明の一態様によれば、ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板を、熱間圧延により該ハット形鋼矢板の形状に造形した後に、幅方向に切断するハット形鋼矢板の製造方法において、前記熱間圧延を終了後、前記ウェブ部が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部の最低温度Ｔfと前記継手部ないし前記腕部の最高温度Ｔgとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）とし、該温度差ΔＴと前記切断をした後の切断面端部の曲がり量との関係を定めておき、この関係に基づき前記曲がり量を許容値内とできるΔＴの範囲が得られるように仕上げ圧延機の最終孔型での圧延において前記継手部の冷却を行うことを特徴とするハット形鋼矢板の製造方法が提供される。 According to one aspect of the present invention, a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion and a joint portion is formed into the shape of the hat-shaped steel sheet pile by hot rolling and then cut in the width direction. In the method for manufacturing a hat-shaped steel sheet pile, the minimum temperature Tf of the flange portion and the joint portion or the arm at the same time point between the completion of the hot rolling and the temperature drop of the web portion to 500 ° C. The difference from the maximum temperature Tg of the part is defined as the temperature difference ΔT (= Tg−Tf), and the relationship between the temperature difference ΔT and the bending amount of the end of the cut surface after the cutting is determined, and based on this relationship. Provided is a method for manufacturing a hat-shaped steel sheet pile, which comprises cooling the joint portion in rolling in the final hole type of a finishing rolling mill so that a range of ΔT capable of keeping the bending amount within an allowable value can be obtained. To.

本発明の一態様によれば、ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板を、熱間圧延により該ハット形鋼矢板の形状に造形した後に、幅方向に切断するハット形鋼矢板の製造方法において、前記熱間圧延を終了後、前記ウェブ部が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部の最低温度Ｔfと前記継手部ないし前記腕部の最高温度Ｔgとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）、継手部ないし腕部の残留応力最大値σgとフランジ部の残留応力最小値σfとの差を残留応力差Δσ（＝σg−σf）とし、前記温度差ΔＴと前記残留応力差Δσとの関係を定めておき、この関係に基づき前記残留応力差Δσを0MPa以上60MPa以下とできるΔＴの範囲が得られるように仕上げ圧延機の最終孔型での圧延において前記継手部の冷却を行うことを特徴とするハット形鋼矢板の製造方法が提供される。 According to one aspect of the present invention, a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion and a joint portion is formed into the shape of the hat-shaped steel sheet pile by hot rolling and then cut in the width direction. In the method for manufacturing a hat-shaped steel sheet pile, the minimum temperature Tf of the flange portion and the joint portion or the arm at the same time point between the completion of the hot rolling and the temperature drop of the web portion to 500 ° C. The difference from the maximum temperature Tg of the part is the temperature difference ΔT (= Tg-Tf), and the difference between the maximum residual stress value σg of the joint or arm and the minimum residual stress σf of the flange part is the residual stress difference Δσ (= σg). −σf), and the relationship between the temperature difference ΔT and the residual stress difference Δσ is determined. Based on this relationship, the finishing rolling mill can obtain a range of ΔT that can make the residual stress difference Δσ 0 MPa or more and 60 MPa or less. Provided is a method for manufacturing a hat-shaped steel sheet pile, which comprises cooling the joint portion in rolling in the final hole type of the above.

本発明の一態様によれば、ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板を、熱間圧延により該ハット形鋼矢板の形状に造形した後に、幅方向に切断するハット形鋼矢板の製造方法において、仕上げ圧延機の最終孔型での圧延において前記継手部を冷却し、該冷却を行う冷媒の単位時間あたりの流量Ｑを前記仕上げ圧延機による圧延の際の圧延速度Ｖで除した値Ｑ／Ｖと、前記切断した後の切断面端部の曲がり量との関係を予め定めておき、該関係から前記曲がり量が許容範囲内となる前記値Ｑ／Ｖの範囲を設定し、前記圧延速度Ｖの変化に対応させて前記値Ｑ／Ｖを前記設定した範囲に収めるように前記冷媒の単位時間当たりの流量Ｑを調整することを特徴とするハット形鋼矢板の製造方法が提供される。 According to one aspect of the present invention, a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion and a joint portion is formed into the shape of the hat-shaped steel sheet pile by hot rolling and then cut in the width direction. In the method for manufacturing a hat-shaped steel sheet pile, the joint portion is cooled in rolling in the final hole type of the finishing rolling mill, and the flow rate Q per unit time of the cooling refrigerant is set in the rolling by the finishing rolling mill. The relationship between the value Q / V divided by the rolling speed V and the bending amount of the cut surface end portion after cutting is determined in advance, and the value Q / V that the bending amount is within the allowable range from the relationship. The hat shaped steel is characterized in that the range of the above is set and the flow rate Q of the refrigerant per unit time is adjusted so as to keep the value Q / V within the set range in accordance with the change of the rolling speed V. A method for manufacturing sheet piles is provided.

本発明の一態様によれば、ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板を、熱間圧延により該ハット形鋼矢板の形状に造形する熱間圧延機と、該熱間圧延により得られたハット形鋼矢板を幅方向に切断する鋸断装置とを有するハット形鋼矢板の製造設備において、前記熱間圧延機の仕上げ圧延機のガイド内に前記継手部を冷却する継手部冷却装置を備え、該継手部冷却装置は前記継手部を冷却する冷媒の単位時間あたりの流量Ｑを調整可能であり、前記仕上げ圧延機は圧延速度Ｖを調整可能であり、前記流量Ｑと圧延速度Ｖの実績を記録する記録手段を有することを特徴とするハット形鋼矢板の製造設備が提供される。 According to one aspect of the present invention, a hot rolling machine that forms a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion, and a joint portion into the shape of the hat-shaped steel sheet pile by hot rolling. In a hat-shaped steel sheet pile manufacturing facility having a sawing device for cutting the hat-shaped steel sheet pile obtained by hot rolling in the width direction, the joint portion is placed in a guide of the finish rolling mill of the hot rolling mill. A joint portion cooling device for cooling is provided, the joint portion cooling device can adjust the flow rate Q of the refrigerant for cooling the joint portion per unit time, and the finish rolling mill can adjust the rolling speed V. Provided is a hat-shaped steel sheet pile manufacturing facility characterized by having a recording means for recording the actual results of the flow rate Q and the rolling speed V.

本発明に係るハット形鋼矢板によれば、熱間あるいは冷間で鋸断した際の長手部端部の変形が抑制された、すなわち、圧延後の熱間、冷間を問わず所定の製品長さに切断されたハット形鋼矢板の端部に「ラッパ変形」「逆ラッパ変形」という形状不良がない、良好な形状のハット形鋼矢板が提供される。また、本発明に係るハット形鋼矢板の製造方法によれば、熱間あるいは冷間で鋸断した際の長手部端部の変形を抑制できるハット形鋼矢板を安価に実現するハット形鋼矢板の製造方法が提供される。また、本発明の一態様によれば、熱間あるいは冷間で鋸断した際の長手部端部の変形を抑制するための製造条件を評価可能であるとともに、この評価にもとづき上記形状不良を抑制可能なハット形鋼矢板の製造設備が提供される。 According to the hat-shaped steel sheet pile according to the present invention, deformation of the longitudinal end portion when sawing hot or cold is suppressed, that is, a predetermined product regardless of whether it is hot or cold after rolling. A well-shaped hat-shaped steel sheet pile is provided in which there is no shape defect such as "trumpet deformation" or "reverse trumpet deformation" at the end of the hat-shaped steel sheet pile cut to a length. Further, according to the method for manufacturing a hat-shaped steel sheet pile according to the present invention, a hat-shaped steel sheet pile that can suppress deformation of the longitudinal end portion when sawed hot or cold is inexpensively realized. Manufacturing method is provided. Further, according to one aspect of the present invention, it is possible to evaluate the manufacturing conditions for suppressing the deformation of the longitudinal end portion when sawing hot or cold, and based on this evaluation, the above-mentioned shape defect can be evaluated. Equipment for the production of suppressable hat-shaped steel sheet piles is provided.

本発明の一実施形態に係るハット形鋼矢板を製造するハット形鋼矢板の製造ラインを示した平面図である。It is a top view which showed the manufacturing line of the hat-shaped steel sheet pile which manufactures the hat-shaped steel sheet pile which concerns on one Embodiment of this invention. 仕上げ圧延機の孔型形状を示す正面図である。It is a front view which shows the hole shape of a finishing rolling mill. Ｋ１孔型の前面に設置された前面ガイドと継手部冷却装置及びウェブ部冷却装置を示す図であり、（ａ）は正面図を、（ｂ）は側面図を示す。It is a figure which shows the front guide, the joint part cooling device and the web part cooling device installed in the front surface of the K1 hole type, (a) shows the front view, and (b) shows the side view. 継手部の冷却制御及びウェブ部の冷却制御の設備構成を示す模式図である。It is a schematic diagram which shows the equipment structure of the cooling control of a joint part and the cooling control of a web part. 仕上げ圧延後のハット形鋼矢板の全幅方向の温度分布の一例を示すグラフである。It is a graph which shows an example of the temperature distribution in the full width direction of a hat-shaped steel sheet pile after finish rolling. ハット形鋼矢板の長手方向残留応力の幅方向分布の一例を示すグラフである。It is a graph which shows an example of the width direction distribution of the longitudinal residual stress of a hat-shaped steel sheet pile. 残留応力差Δσと端部変形量（継手部の曲がり量）との関係を示すグラフである。It is a graph which shows the relationship between the residual stress difference Δσ and the end deformation amount (the bending amount of a joint part). 温度差ΔＴと端部変形量（継手部の曲がり量）との関係を示すグラフである。It is a graph which shows the relationship between the temperature difference ΔT and the amount of deformation of an end part (the amount of bending of a joint part). 温度差ΔＴと残留応力差Δσとの関係を示すグラフである。It is a graph which shows the relationship between the temperature difference ΔT and the residual stress difference Δσ. Ｑ／Ｖと端部変形量（継手部の曲がり量）との関係を示すグラフである。It is a graph which shows the relationship between Q / V and the amount of deformation of an end part (the amount of bending of a joint part). ハット形鋼矢板を示し、（ａ）はハット形鋼矢板の断面形状の全体を示す図、（ｂ）は、ハット形鋼矢板の継手部を拡大した状態を示す図、（ｃ）は、ハット形鋼矢板の継手部同士が嵌合する状態を示す図である。A hat-shaped steel sheet pile is shown, (a) is a view showing the entire cross-sectional shape of the hat-shaped steel sheet pile, (b) is a view showing an enlarged state of a joint portion of the hat-shaped steel sheet pile, and (c) is a hat. It is a figure which shows the state which the joint part of a shaped steel sheet pile is fitted with each other. ハット形鋼矢板の長手方向端部の変形を示す模式図であり、（ａ）はラッパ変形を、（ｂ）は逆ラッパ変形を示す。It is a schematic diagram which shows the deformation of the end portion in the longitudinal direction of a hat-shaped steel sheet pile, (a) shows the trumpet deformation, and (b) shows the reverse trumpet deformation. ハット形鋼矢板に反り（上反り）がある状態を示す模式図である。It is a schematic diagram which shows the state which a hat-shaped steel sheet pile has a warp (upward warp). ウェブ冷却水量Ｑｗ／圧延速度Ｖと反り量Ｓとの関係を示すグラフである。It is a graph which shows the relationship between the web cooling water amount Qw / rolling speed V, and the warpage amount S.

以下、本発明の実施形態を図面に基づいて説明する。なお、各図面は模式的なものであって、現実のものとは異なる場合がある。また、以下の実施形態は、本発明の技術的思想を具体化するための装置や方法を例示するものであり、構成を下記のものに特定するものでない。すなわち、本発明の技術的思想は、特許請求の範囲に記載された技術的範囲内において、種々の変更を加えることができる。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing is a schematic one and may differ from the actual one. In addition, the following embodiments exemplify devices and methods for embodying the technical idea of the present invention, and do not specify the configuration to the following. That is, the technical idea of the present invention can be modified in various ways within the technical scope described in the claims.

図１はハット形鋼矢板の製造ラインを示した平面図である。ハット形鋼矢板の製造ラインは、加熱炉１０、複数台の熱間圧延機、すなわち、粗圧延機１１、中間圧延機１２、及び仕上げ圧延機１３を備える。また、ハット形鋼矢板の製造ラインは、熱間圧延機の仕上げ圧延機１３の下流側に、熱間鋸断装置１４を備える。中間圧延機１２は２台の圧延機をタンデムに配置して構成されている。
加熱炉１０で素材であるスラブやブルームを所定の温度に加熱し、粗圧延機１１、中間圧延機１２、仕上げ圧延機１３の順に熱間で孔型圧延を行い、図１１に示すハット形の製品形状に仕上げられる。熱間鋸断装置１４は、圧延で延ばされた製品を所定の長さに熱間で切断するものである。 FIG. 1 is a plan view showing a production line for a hat-shaped steel sheet pile. The hat-shaped steel sheet pile production line includes a heating furnace 10, a plurality of hot rolling mills, that is, a rough rolling mill 11, an intermediate rolling mill 12, and a finishing rolling mill 13. Further, the hat-shaped steel sheet pile production line is provided with a hot saw cutting device 14 on the downstream side of the finish rolling mill 13 of the hot rolling mill. The intermediate rolling mill 12 is configured by arranging two rolling mills in tandem.
The slabs and blooms, which are the raw materials, are heated to a predetermined temperature in the heating furnace 10, and the rough rolling mill 11, the intermediate rolling mill 12, and the finishing rolling mill 13 are hot-rolled in this order, and the hat-shaped rolling mill shown in FIG. 11 is formed. Finished in product shape. The hot saw cutting device 14 hot cuts a rolled product to a predetermined length.

各圧延機には、複数の孔型が刻設されており、例えば仕上げ圧延機１３では図２に示すように、上圧延ロール２１及び下圧延ロール２２に２つの孔型Ｋ２，Ｋ１が刻設されている。Ｋ１孔型が最終圧延を行う孔型であり、爪曲げと成形圧延が同時に行われる。なお，仕上げ圧延は合計３パスのリバース圧延となっており、Ｋ２孔型圧延は１パス目の圧延で仕上げ圧延機１３の前面（図１の左側）から後面（図１の右側）側に向かって圧延される。Ｋ１孔型圧延は２パス目のリバース圧延で行われ、仕上げ圧延機１３の後面から前面側に向かって圧延される。仕上げ圧延の３パス目は、仕上げ圧延機１３の前面から後面へ向けて被圧延材を通すが、圧下を行わないダミー圧延パスである。 A plurality of hole molds are engraved in each rolling mill. For example, in the finish rolling mill 13, two hole molds K2 and K1 are engraved on the upper rolling roll 21 and the lower rolling roll 22 as shown in FIG. Has been done. The K1 hole type is a hole type for final rolling, and claw bending and forming rolling are performed at the same time. The finish rolling is a total of 3 passes of reverse rolling, and the K2 hole type rolling is the first pass of rolling from the front surface (left side in FIG. 1) to the rear surface (right side in FIG. 1) of the finish rolling mill 13. Is rolled. The K1 hole type rolling is performed by reverse rolling in the second pass, and is rolled from the rear surface to the front surface side of the finish rolling mill 13. The third pass of finish rolling is a dummy rolling pass in which the material to be rolled is passed from the front surface to the rear surface of the finish rolling mill 13 but not rolled.

図３は、このＫ１孔型の前面に設置された前面ガイド２３と，前面ガイド２３内に設置された継手部冷却装置２５及びウェブ部冷却装置２６を示す模式図である。図３（ａ）は圧延方向から見た正面図であり、図３（ｂ）は側面図である。前面ガイド２３は、ハット形鋼矢板のウェブ部２、フランジ部３、及び腕部５を案内する上ガイド２３ａと下ガイド２３ｂとを有する。上ガイド２３ａ内には、継手部冷却ヘッダー２５ａが配置され、この継手部冷却ヘッダー２５ａには継手部冷却ノズル２５ｂが設けられている。継手部冷却ヘッダー２５ａは圧延方向（図３（ｂ）中の左右方向）に延在し、継手部冷却ノズル２５ｂはハット形鋼矢板１の継手部４に対向する位置に、継手部冷却ヘッダー２５ａの延在方向に沿って複数配置されている。そして継手部冷却ノズル２５ｂが継手部４に向けて冷媒を噴出可能となっており、この継手部冷却ノズル２５ｂでハット形鋼矢板の継手部４が冷却される。継手部冷却ヘッダー２５ａと継手部冷却ノズル２５ｂと、後述する継手部冷却水流量調整弁２５ｅおよびこの継手部冷却水流量調整弁２５ｅの開度調整を行う演算装置３０が継手部冷却装置２５を構成している。この図では上ガイド２３ａに継手部冷却装置２５が配置され、上方から継手部４の冷却を行っているが，下ガイド２３ｂに継手部冷却ヘッダー２５ａ、継手部冷却ノズル２５ｂを配置し、下方から継手部４を冷却してもよい。また、継手部４内で最も冷却を行うべき部位は、継手部４の突起部４ａ（図１１（ｂ）参照）であるが、この突起部４ａを中心として、爪部４ｂや腕部５にかけて冷却を行ってもよい。さらに、後面ガイド２４（図４参照）に継手部冷却装置２５を設けてもよい。 FIG. 3 is a schematic view showing a front guide 23 installed on the front surface of the K1 hole type, and a joint portion cooling device 25 and a web portion cooling device 26 installed in the front guide 23. FIG. 3A is a front view seen from the rolling direction, and FIG. 3B is a side view. The front guide 23 has an upper guide 23a and a lower guide 23b that guide the web portion 2, the flange portion 3, and the arm portion 5 of the hat-shaped steel sheet pile. A joint portion cooling header 25a is arranged in the upper guide 23a, and the joint portion cooling nozzle 25b is provided in the joint portion cooling header 25a. The joint portion cooling header 25a extends in the rolling direction (the left-right direction in FIG. 3B), and the joint portion cooling nozzle 25b is located at a position facing the joint portion 4 of the hat-shaped steel sheet pile 1, and the joint portion cooling header 25a Multiple pieces are arranged along the extending direction of. Then, the joint portion cooling nozzle 25b can eject the refrigerant toward the joint portion 4, and the joint portion 4 of the hat-shaped steel sheet pile is cooled by the joint portion cooling nozzle 25b. The joint portion cooling header 25a, the joint portion cooling nozzle 25b, the joint portion cooling water flow rate adjusting valve 25e described later, and the arithmetic device 30 for adjusting the opening degree of the joint portion cooling water flow rate adjusting valve 25e constitute the joint portion cooling device 25. doing. In this figure, the joint portion cooling device 25 is arranged on the upper guide 23a to cool the joint portion 4 from above, but the joint portion cooling header 25a and the joint portion cooling nozzle 25b are arranged on the lower guide 23b from below. The joint portion 4 may be cooled. Further, the portion of the joint portion 4 to be cooled most is the protrusion 4a of the joint portion 4 (see FIG. 11B), but the protrusion 4a is centered on the claw portion 4b and the arm portion 5. Cooling may be performed. Further, the joint portion cooling device 25 may be provided on the rear surface guide 24 (see FIG. 4).

上ガイド２３ａにはウェブ上面冷却ヘッダー２６ａおよびウェブ上面冷却ノズル２６ｂも配置され、ハット形鋼矢板１のウェブ部２上面を冷却することができる。すなわち、ウェブ上面冷却ノズル２６ｂは、ウェブ上面冷却ヘッダー２６ａのウェブ部２上面に対向する位置に配置され、ウェブ部２上面に対して冷媒を噴射可能とされている。下ガイド２３ｂにはウェブ下面冷却ヘッダー２６ｃおよびウェブ下面冷却ノズル２６ｄが配置されており、ハット形鋼矢板１のウェブ部２下面（裏面）を冷却する。すなわち、ウェブ下面冷却ノズル２６ｄは、ウェブ下面冷却ヘッダー２６ｃのウェブ部２下面に対向する位置に配置され、ウェブ部２下面に対して冷媒を噴射可能とされている。ウェブ上面冷却ヘッダー２６ａおよびウェブ下面冷却ヘッダー２６ｃは、継手部冷却ヘッダー２５ａと同様に圧延方向（図３（ｂ）中の左右方向）に延在しており、ウェブ上面冷却ノズル２６ｂ及びウェブ下面冷却ノズル２６ｄは、所定の冷却能力が発揮できるよう、それぞれヘッダーの延在方向に複数個ずつ配置されている。これら、ウェブ上面冷却ヘッダー２６ａ、ウェブ上面冷却ノズル２６ｂ、ウェブ下面冷却ヘッダー２６ｃ、及びウェブ下面冷却ノズル２６ｄと、後述するウェブ上面冷却水流量調整弁２６ｅ、ウェブ下面冷却水流量調整弁２６ｆ、および、これらウェブ上面冷却水流量調整弁２６ｅ、ウェブ下面冷却水流量調整弁２６ｆの開度調整を行う演算装置３０がウェブ部冷却装置２６を構成している。なお、後面ガイド２４にウェブ部冷却装置２６を設けてもよい。 A web upper surface cooling header 26a and a web upper surface cooling nozzle 26b are also arranged on the upper guide 23a, and the upper surface of the web portion 2 of the hat-shaped steel sheet pile 1 can be cooled. That is, the web upper surface cooling nozzle 26b is arranged at a position facing the upper surface of the web portion 2 of the web upper surface cooling header 26a, and the refrigerant can be injected to the upper surface of the web portion 2. A web lower surface cooling header 26c and a web lower surface cooling nozzle 26d are arranged on the lower guide 23b to cool the lower surface (back surface) of the web portion 2 of the hat-shaped steel sheet pile 1. That is, the web lower surface cooling nozzle 26d is arranged at a position facing the lower surface of the web portion 2 of the web lower surface cooling header 26c, and the refrigerant can be injected to the lower surface of the web portion 2. The web upper surface cooling header 26a and the web lower surface cooling header 26c extend in the rolling direction (left-right direction in FIG. 3B) like the joint cooling header 25a, and the web upper surface cooling nozzle 26b and the web lower surface cooling A plurality of nozzles 26d are arranged in the extending direction of the header so that a predetermined cooling capacity can be exhibited. These, the web upper surface cooling header 26a, the web upper surface cooling nozzle 26b, the web lower surface cooling header 26c, and the web lower surface cooling nozzle 26d, the web upper surface cooling water flow rate adjusting valve 26e, the web lower surface cooling water flow rate adjusting valve 26f, and The web unit cooling device 26 is composed of a calculation device 30 that adjusts the opening degree of the web upper surface cooling water flow rate adjusting valve 26e and the web lower surface cooling water flow rate adjusting valve 26f. The web portion cooling device 26 may be provided on the rear surface guide 24.

図４は、仕上げ圧延機１３の最終孔型Ｋ１圧延の際に、継手部４の冷却制御およびウェブ部２の冷却制御を可能とした設備構成を示す模式図である。孔型Ｋ１の前面ガイド２３の上ガイド２３ａに設けられた左右のそれぞれの継手部冷却ヘッダー２５ａ、ウェブ上面冷却ヘッダー２６ａ、ウェブ下面冷却ヘッダー２６ｃ（図４では図示省略）は、それぞれ、冷却水配管によって冷却水ポンプ２９に接続されている。それぞれの冷却水配管には、流量調整弁２５ｅ（継手部冷却水流量調整弁２５ｅ），２６ｅ（ウェブ上面冷却水流量調整弁２６ｅ），２６ｆ（ウェブ下面冷却水流量調整弁２６ｆ：図示省略）が設けられており、これら流量調整弁２５ｅ，２６ｅ，２６ｆにより冷却ヘッダー２５ａ，２６ａ，２６ｃへの冷却水供給量、すなわち、単位時間当たりの流量Ｑを個別に調整可能となっている。流量調整弁２５ｅ，２６ｅ，２６ｆの開度調整は演算装置３０が行う。 FIG. 4 is a schematic view showing an equipment configuration that enables cooling control of the joint portion 4 and cooling control of the web portion 2 during the final hole type K1 rolling of the finish rolling mill 13. The left and right joint cooling headers 25a, the web upper surface cooling header 26a, and the web lower surface cooling header 26c (not shown in FIG. 4) provided on the upper guide 23a of the front guide 23 of the hole type K1 are cooling water pipes, respectively. Is connected to the cooling water pump 29. Each cooling water pipe has a flow rate adjusting valve 25e (joint part cooling water flow rate adjusting valve 25e), 26e (web upper surface cooling water flow rate adjusting valve 26e), and 26f (web lower surface cooling water flow rate adjusting valve 26f: not shown). The flow rate adjusting valves 25e, 26e, 26f are provided so that the amount of cooling water supplied to the cooling headers 25a, 26a, 26c, that is, the flow rate Q per unit time can be individually adjusted. The arithmetic unit 30 adjusts the opening degree of the flow rate adjusting valves 25e, 26e, 26f.

演算装置３０は、流量調整弁２５ｅ，２６ｅ，２６ｆの開度調整とともに、仕上げ圧延機１３のミルモータ１３ａに回転数指令の信号を送り、仕上げ圧延機１３によるハット形鋼矢板１の圧延速度の制御も行う。演算装置３０は、上位コンピュータ（図示せず）からの被圧延材の圧延条件情報にもとづき、仕上げ圧延機１３の仕上げ圧延速度Ｖ（以下、単に圧延速度Ｖとも云う）を調整するために、ミルモータ１３ａへ回転数指令の信号を送る。圧延速度Ｖ（ｍ／秒）は、圧延の噛み込み時に定常部よりも速くするほか、曲がりの発生有無や、焼付き等の疵の発生有無にもとづいて調整が行われる。演算装置３０は、流量調整弁２５ｅ，２６ｅ，２６ｆの開度の調整を行い、継手部４やウェブ部２の上面、ウェブ部２の下面を冷却する冷媒（本実施形態では水）の単位時間あたりの流量Ｑ（リットル／秒）の調整を行う流量制御手段として機能する。圧延速度Ｖが変化すると一定量の冷却能力を発揮させるための冷媒の単位時間あたりの流量Ｑは変化するため、本実施形態では、演算装置３０は圧延速度Ｖの変化に応じて各冷却ヘッダー２５ａ，２６ａ，２６ｃへ供給する冷却水の単位時間あたりの流量Ｑを調整するようにしている。具体的には、各冷却ヘッダーへ供給する冷却水の単位時間あたりの流量Ｑを圧延速度Ｖで除した値Ｑ／Ｖが一定範囲内となるように、演算装置３０が各流量調整弁２５ｅ，２６ｅ，２６ｆの開度を調整し、各冷却ヘッダー２５ａ，２６ａ，２６ｃへの冷却水の流量Ｑを制御する。 The arithmetic unit 30 adjusts the opening degrees of the flow rate adjusting valves 25e, 26e, and 26f, sends a rotation speed command signal to the mill motor 13a of the finishing rolling mill 13, and controls the rolling speed of the hat-shaped steel sheet pile 1 by the finishing rolling mill 13. Also do. The arithmetic unit 30 is a mill motor for adjusting the finish rolling speed V (hereinafter, also simply referred to as rolling speed V) of the finish rolling mill 13 based on the rolling condition information of the material to be rolled from a higher-level computer (not shown). A rotation speed command signal is sent to 13a. The rolling speed V (m / sec) is made faster than the stationary portion at the time of biting in rolling, and is adjusted based on the presence or absence of bending and the presence or absence of flaws such as seizure. The arithmetic unit 30 adjusts the opening degree of the flow rate adjusting valves 25e, 26e, 26f, and the unit time of the refrigerant (water in this embodiment) for cooling the upper surface of the joint portion 4, the upper surface of the web portion 2, and the lower surface of the web portion 2. It functions as a flow rate control means for adjusting the flow rate Q (liter / sec) per unit. When the rolling speed V changes, the flow rate Q per unit time of the refrigerant for exerting a constant amount of cooling capacity changes. Therefore, in the present embodiment, the arithmetic unit 30 changes each cooling header 25a according to the change in the rolling speed V. , 26a, 26c are adjusted so that the flow rate Q of the cooling water supplied per unit time is adjusted. Specifically, the calculation device 30 sets each flow rate adjusting valve 25e, so that the value Q / V obtained by dividing the flow rate Q of the cooling water supplied to each cooling header per unit time by the rolling speed V is within a certain range. The opening degrees of 26e and 26f are adjusted to control the flow rate Q of the cooling water to the cooling headers 25a, 26a and 26c.

Ｑ／Ｖの具体的な数値範囲は、継手部冷却装置２５については、Ｑ／Ｖの値と熱間鋸断装置１４で切断した後の切断面端部の曲がり量との関係、あるいはＱ／Ｖの値と仕上げ圧延後の所定時点におけるフランジ部の最低温度Ｔfと継手部４ないし腕部５の最高温度Ｔgとの温度差ΔＴ（＝Ｔｇ−Ｔｆ）との関係を予め定めておき、これらいずれかの関係から曲がり量が許容範囲内となるＱ／Ｖの範囲、あるいは、温度差ΔＴが所定範囲となるＱ／Ｖの範囲として設定してある。Ｑ／Ｖがある範囲となるように継手部冷却装置２５からの冷却水の流量Ｑを調整することで、切断面端部の曲がりが抑制できる理由の詳細は後述する。 The specific numerical range of Q / V is the relationship between the Q / V value and the bending amount of the cut surface end after cutting with the hot saw cutting device 14 for the joint cooling device 25, or Q / The relationship between the value of V and the temperature difference ΔT (= Tg−Tf) between the minimum temperature Tf of the flange portion and the maximum temperature Tg of the joint portion 4 or the arm portion 5 at a predetermined time after finish rolling is determined in advance. From either relationship, it is set as a Q / V range in which the bending amount is within the allowable range, or a Q / V range in which the temperature difference ΔT is within a predetermined range. The details of the reason why the bending of the cut surface end can be suppressed by adjusting the flow rate Q of the cooling water from the joint cooling device 25 so that the Q / V is within a certain range will be described later.

また、ウェブ部冷却装置２６によりウェブ部２を冷却する理由は、後述するとおり、圧延後のＣＢ（クーリングベッド）上での自然冷却時の反りを防止するためである。したがって、ウェブ部冷却装置２６についてのＱ／Ｖの具体的な数値範囲については、Ｑ／Ｖの値とクーリングベッド上でのハット形鋼矢板の反り量との関係を予め定めておき、該関係から反り量が許容範囲となるＱ／Ｖの範囲として設定してある。 Further, the reason why the web portion 2 is cooled by the web portion cooling device 26 is to prevent warpage during natural cooling on the CB (cooling bed) after rolling, as will be described later. Therefore, regarding the specific numerical range of Q / V for the web section cooling device 26, the relationship between the Q / V value and the amount of warpage of the hat-shaped steel sheet pile on the cooling bed is determined in advance, and the relationship is determined. It is set as the range of Q / V where the amount of warpage is within the permissible range.

仕上げ圧延機１３により仕上げ圧延が施されたハット形鋼矢板１は、ハット形鋼矢板１の搬送方向に沿って配列されたテーブルローラー３５により下流側へと送られるが、仕上げ圧延機１３の下流側には温度計３１が配置されており、この温度計３１は、仕上げ圧延後、すなわち、最終孔型Ｋ１による圧延が施された後のハット形鋼矢板１の幅方向の温度プロフィルの測定が可能となっている。温度計３１による温度プロフィルの測定結果は演算装置３０に送られる。前述の温度差ΔＴ（＝Ｔｇ−Ｔｆ）を所定範囲としたい場合、演算装置３０は、温度測定結果から得られるΔＴと目標とするΔＴとを比較し、次材圧延時には、目標とするΔＴが得られるように継手部冷却装置２５やウェブ部冷却装置２６の流量調整弁２５ｅ，２６ｅ，２６ｆへの開度設定指令や、仕上げ圧延機１３のミルモータ１３ａへの回転数指令を補正する。 The hat-shaped steel sheet pile 1 that has been finish-rolled by the finish-rolling machine 13 is sent to the downstream side by the table rollers 35 arranged along the transport direction of the hat-shaped steel sheet pile 1, but is downstream of the finish-rolling machine 13. A thermometer 31 is arranged on the side, and this thermometer 31 measures the temperature profile in the width direction of the hat-shaped steel sheet pile 1 after finish rolling, that is, after rolling by the final hole type K1. It is possible. The measurement result of the temperature profile by the thermometer 31 is sent to the arithmetic unit 30. When the above-mentioned temperature difference ΔT (= Tg−Tf) is desired to be within a predetermined range, the arithmetic unit 30 compares the ΔT obtained from the temperature measurement result with the target ΔT, and at the time of rolling the next material, the target ΔT is set. The opening degree setting command to the flow rate adjusting valves 25e, 26e, 26f of the joint portion cooling device 25 and the web portion cooling device 26 and the rotation speed command to the mill motor 13a of the finishing rolling mill 13 are corrected so as to be obtained.

左側の継手部４と右側の継手部４、及びウェブ部２の面の冷媒（本実施形態では冷却水）の流量は、それぞれ個別に設定することができる。ハット形鋼矢板１の継手形状は，図１１（ｂ）に示すように左右で非対称な形状であるため、左右の継手部４で温度差が生じやすいが、左右の継手部４の冷却水流量を個別に設定することで、一方の継手部のみの変形が問題になる場合にも対応が可能となる。 The flow rates of the refrigerant (cooling water in this embodiment) on the surfaces of the left joint portion 4, the right joint portion 4, and the web portion 2 can be set individually. As shown in FIG. 11B, the joint shape of the hat-shaped steel sheet pile 1 is asymmetrical on the left and right sides, so that a temperature difference is likely to occur between the left and right joint parts 4, but the cooling water flow rate of the left and right joint parts 4 By setting individually, it is possible to deal with the problem of deformation of only one joint.

また、ウェブ部２の面の冷却は，圧延後のＣＢ（クーリングベッド）上での自然冷却時の上反り発生抑止に効果がある。ＣＢ上で上反りが大きい場合、ＣＢでの製品の搬送に支障をきたすほか、常温まで冷却したのちに行うローラー矯正において、製品がロールに噛み込んでいかないといった不具合が発生する。上述のとおりウェブ部２の面の冷却を行うことで、かような不具合を抑止することができる。 Further, cooling the surface of the web portion 2 is effective in suppressing the occurrence of warpage during natural cooling on the CB (cooling bed) after rolling. If the warp is large on the CB, the transportation of the product on the CB will be hindered, and in the roller straightening performed after cooling to room temperature, the product will not bite into the roll. By cooling the surface of the web portion 2 as described above, such a problem can be suppressed.

なお、演算装置３０は、圧延を行う毎に、各冷却ヘッダー２５ａ，２６ａ，２６ｃへ供給する冷却水の単位時間あたりの流量Ｑと圧延速度Ｖの実績を記録する記録手段を有している。この記録手段は、圧延中の流量Ｑと圧延速度Ｖの経時変化のデータを記録可能である。詳細は後述するが、継手部４を冷却する冷媒の単位時間あたりの流量Ｑ、圧延速度Ｖは継手部４の曲がり量、すなわち、切断面端部の曲がり量に影響を及ぼす。したがって、これらＱ、Ｖの実績を記録しておくことで、得られたＱ、Ｖと、実際に得られた継手部４の曲がり量との関係を調査することで、最適な流量Ｑおよび圧延速度Ｖを求めることができる。 The arithmetic unit 30 has a recording means for recording the actual results of the flow rate Q and the rolling speed V per unit time of the cooling water supplied to the cooling headers 25a, 26a, and 26c each time the rolling is performed. This recording means can record data on changes over time in the flow rate Q and the rolling speed V during rolling. Although the details will be described later, the flow rate Q and the rolling speed V per unit time of the refrigerant that cools the joint portion 4 affect the bending amount of the joint portion 4, that is, the bending amount of the cut surface end portion. Therefore, by recording the results of these Q and V, the optimum flow rate Q and rolling can be investigated by investigating the relationship between the obtained Q and V and the actually obtained bending amount of the joint portion 4. The velocity V can be obtained.

次に本発明に至った経緯について説明する。先ず、本発明のハット形鋼矢板１について、継手部４ないし腕部５の残留応力の最大値σｇとフランジ部３の残留応力の最小値σｆとの残留応力差Δσ（＝σｇ−σｆ）を特定した理由について説明する。
本発明者らは、種々の条件で熱間圧延されローラー矯正されたハット形鋼矢板１について、圧延終了時の温度分布、製品での残留応力分布と端部の変形について、各種の調査、検討を行った。 Next, the background to the present invention will be described. First, for the hat-shaped steel sheet pile 1 of the present invention, the residual stress difference Δσ (= σg−σf) between the maximum residual stress σg of the joint portion 4 to the arm portion 5 and the minimum residual stress σf of the flange portion 3 is determined. The reason for the identification will be explained.
The present inventors have conducted various investigations and studies on the temperature distribution at the end of rolling, the residual stress distribution in the product, and the deformation of the end of the hat-shaped steel sheet pile 1 which has been hot-rolled and roller-straightened under various conditions. Was done.

図５は仕上げ圧延後のハット形鋼矢板１を熱間鋸断装置１４にて鋸断する際に、熱間鋸断装置１４の入側でハット形鋼矢板１の全幅方向の温度プロフィルを測定した例である。圧延素材２本の温度プロフィルを示しており、太線は、先に説明した継手部冷却装置２５で左側の継手部４を実験的に冷媒として水を用いて冷却したケースである。この例のように、ハット形鋼矢板１は左右の継手部４およびウェブ部２が、フランジ部３および腕部５よりも高温で仕上げられる。また、継手部４の冷却によって、継手部４の冷却をしない場合よりも、継手部４の温度を低温に仕上げられることがわかる。 FIG. 5 shows that when the hat-shaped steel sheet pile 1 after finish rolling is sawed by the hot sawing device 14, the temperature profile of the hat-shaped steel sheet pile 1 in the entire width direction is measured on the entry side of the hot sawing device 14. This is an example. The temperature profile of the two rolled materials is shown, and the thick line shows the case where the joint portion 4 on the left side is experimentally cooled using water as a refrigerant in the joint portion cooling device 25 described above. As in this example, in the hat-shaped steel sheet pile 1, the left and right joint portions 4 and the web portion 2 are finished at a higher temperature than the flange portion 3 and the arm portion 5. Further, it can be seen that the cooling of the joint portion 4 makes the temperature of the joint portion 4 lower than that in the case where the joint portion 4 is not cooled.

図６は、図５に示した２本の素材から製品化したハット形鋼矢板１について、冷間でローラー矯正を行った後の長手方向の残留応力を幅方向にわたって測定した結果である。ローラー矯正後も残留応力があり、ウェブ部２の幅方向中央と継手部４の近傍で引張りの残留応力、フランジ部３の近傍で圧縮の残留応力となっている。〇で示す仕上げ圧延で継手部４の冷却を実施した製品は、△で示した継手部４の冷却なしの製品に対して、継手部４とフランジ部３の近傍の残留応力の差が小さくなっていることが分かる。 FIG. 6 shows the results of measuring the residual stress in the longitudinal direction after cold roller straightening for the hat-shaped steel sheet pile 1 commercialized from the two materials shown in FIG. 5 over the width direction. There is residual stress even after roller straightening, with tensile residual stress near the center of the web portion 2 in the width direction and near the joint portion 4, and compressive residual stress near the flange portion 3. The product in which the joint portion 4 is cooled by the finish rolling indicated by ◯ has a smaller difference in residual stress in the vicinity of the joint portion 4 and the flange portion 3 than the product in which the joint portion 4 is not cooled shown by Δ. You can see that.

この２つの製品について、継手部４の曲がり量を調査したところ、継手部４の水冷なしの製品は、左側の継手部４で+6.7ｍｍ、右側の継手部４で+6.1mmであり、継手部４の水冷を実施した製品は、左側の継手部４で+3.7ｍｍ、右側の継手部４で+4.9mmであり、仕上げ圧延での継手部４の水冷によって継手部４の変形が小さくなっていることが認められた。なお、継手部４の曲がり量は、図１２に示すように、長手定常部の継手外縁線を延長し、この外延線と長手端部の継手部４の外端との幅方向の位置の差をとったものであり、端部が広がっている場合を符号＋で、端部が狭まっている場合を符号−とした。 When the amount of bending of the joint portion 4 was investigated for these two products, the product without water cooling of the joint portion 4 was +6.7 mm at the joint portion 4 on the left side and +6.1 mm at the joint portion 4 on the right side. The product in which the joint portion 4 is water-cooled is +3.7 mm at the left joint portion 4 and +4.9 mm at the right joint portion 4, and the deformation of the joint portion 4 is reduced by the water cooling of the joint portion 4 in the finish rolling. It was confirmed that. As shown in FIG. 12, the bending amount of the joint portion 4 is the difference in the position in the width direction between the outer extension line of the joint outer edge line of the longitudinal stationary portion and the outer end of the joint portion 4 of the longitudinal end portion. The case where the end is widened is designated as a symbol +, and the case where the end is narrowed is designated as a symbol −.

次に、上記の知見をより定量的に評価するために、図６で定義を示した継手部４の近傍の残留応力の最大値σｇとフランジ部３の近傍の残留応力の最小値σｆとの差σg−σfを残留応力差Δσとし、各種の製品での継手部４の曲がり量との定量的な関係を調査していった。この調査結果を図７に示す。図７では、有効幅900mmのハット形鋼矢板１の内、ウェブ厚10.8mmで有効高さが230mmの10Hサイズを〇で、ウェブ厚13.2mmで有効高さが300mmの25Hサイズを△で示している。なお、残留応力は、ハット形鋼矢板の長手方向中央の表裏面に全幅方向に複数のひずみゲージを貼りつけていき、これらの初期ひずみを計測し、この後、ひずみゲージ貼付位置のすぐ傍でハット形鋼矢板を幅方向に冷間鋸断し、冷間鋸断によって残留応力が解放された後のひずみをこれらひずみゲージで計測し、初期ひずみからのひずみの変化量から、各部位の残留応力を算出して求めている。 Next, in order to evaluate the above findings more quantitatively, the maximum value σg of the residual stress in the vicinity of the joint portion 4 and the minimum value σf of the residual stress in the vicinity of the flange portion 3 shown in FIG. The difference σg−σf was defined as the residual stress difference Δσ, and the quantitative relationship with the bending amount of the joint portion 4 in various products was investigated. The results of this survey are shown in FIG. In Fig. 7, of the hat-shaped steel sheet pile 1 with an effective width of 900 mm, the 10H size with a web thickness of 10.8 mm and an effective height of 230 mm is indicated by 〇, and the 25H size with a web thickness of 13.2 mm and an effective height of 300 mm is indicated by △. ing. For residual stress, a plurality of strain gauges are attached to the front and back surfaces in the center of the longitudinal direction of the hat-shaped steel sheet pile in the overall width direction, these initial strains are measured, and then immediately near the strain gauge attachment position. The hat-shaped steel sheet pile is cold-sawed in the width direction, and the strain after the residual stress is released by the cold-saw is measured with these strain gauges, and the residual strain of each part is measured from the amount of change in strain from the initial strain. The stress is calculated and calculated.

図７から、継手部４の曲がり量は、残留応力差Δσで整理できることがわかる。ハット形鋼矢板１を使用する際には図１１（ｃ）に示すように左右の継手部４を嵌合させることから、継手部４の曲がり量には嵌合のための許容差があり、ハット形鋼矢板１の場合、約±４ｍｍ以内とする必要がある。継手部４の曲がり量が約±４ｍｍ以内を満たす残留応力差Δσの範囲は、10H、25Hの場合ともに、0〜60ＭＰａとなる。 From FIG. 7, it can be seen that the bending amount of the joint portion 4 can be arranged by the residual stress difference Δσ. When the hat-shaped steel sheet pile 1 is used, the left and right joint portions 4 are fitted as shown in FIG. 11 (c). Therefore, the bending amount of the joint portion 4 has a tolerance for fitting. In the case of the hat-shaped steel sheet pile 1, it must be within about ± 4 mm. The range of the residual stress difference Δσ that satisfies the bending amount of the joint portion 4 within about ± 4 mm is 0 to 60 MPa in both cases of 10H and 25H.

つまり、継手部４の残留応力の最大値σｇとフランジ部３の残留応力の最小値σｆとの差である残留応力差Δσ（＝σｇ−σｆ）を０MPa以上６０MPa以下の範囲内とすることで、継手部４の曲がり量を継手嵌合に問題のない程度とすることができる。なお、継手部４を局部的に冷却して継手部４の温度が腕部５の温度よりも低下する場合は、継手部４の残留応力の最大値よりも腕部５の残留応力の最大値が大きくなる場合があり得る。この場合、継手部４の残留応力の最大値σｇとフランジ部３の残留応力の最小値σｆの差が６０MPa以下であっても、腕部５の残留圧縮応力の最大値とフランジ部３の残留圧縮応力の最小値σｆが６０MPaを超えると、継手部４の曲がり量が約±４ｍｍ以内とならなくなる。よって、本発明のハット形鋼矢板１では、継手部４ないし腕部５の残留応力最大値σgとフランジ部３の残留応力最小値σfとの残留応力差Δσ（＝σg−σf）が0MPa以上60MPa以下である必要がある。 That is, by setting the residual stress difference Δσ (= σg−σf), which is the difference between the maximum residual stress value σg of the joint portion 4 and the minimum residual stress value σf of the flange portion 3, within the range of 0 MPa or more and 60 MPa or less. The bending amount of the joint portion 4 can be set to such an extent that there is no problem in fitting the joint. When the joint portion 4 is locally cooled and the temperature of the joint portion 4 is lower than the temperature of the arm portion 5, the maximum value of the residual stress of the arm portion 5 is larger than the maximum value of the residual stress of the joint portion 4. Can be large. In this case, even if the difference between the maximum residual stress value σg of the joint portion 4 and the minimum residual stress value σf of the flange portion 3 is 60 MPa or less, the maximum value of the residual compressive stress of the arm portion 5 and the residual value of the flange portion 3 remain. When the minimum value σf of the compressive stress exceeds 60 MPa, the bending amount of the joint portion 4 is not within about ± 4 mm. Therefore, in the hat-shaped steel sheet pile 1 of the present invention, the residual stress difference Δσ (= σg−σf) between the maximum residual stress value σg of the joint portion 4 or the arm portion 5 and the minimum residual stress value σf of the flange portion 3 is 0 MPa or more. Must be 60MPa or less.

次に、継手部４の冷却により継手部４の曲がり量を抑制でき、本発明のハット形鋼矢板１の製造方法を完成するに至った検討結果について説明する。
図５で定義を示した継手部４の最高温度Ｔｇとフランジ部３の最低温度Ｔｆとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）とし、製品での継手部４の曲がり量との関係を調査した。また、左右それぞれの継手部４を個別のデータとした。この調査結果を図８に示す。図８から、継手部４の曲がり量は、温度差ΔＴでも整理することができることがわかる。継手部４の曲がり量が約±４ｍｍ以内を満たす温度差ΔＴの範囲は、本データの場合、30〜50℃となる。 Next, the results of studies that have been able to suppress the amount of bending of the joint portion 4 by cooling the joint portion 4 and have completed the method for manufacturing the hat-shaped steel sheet pile 1 of the present invention will be described.
The difference between the maximum temperature Tg of the joint portion 4 and the minimum temperature Tf of the flange portion 3 shown in FIG. 5 is defined as the temperature difference ΔT (= Tg−Tf), and the relationship with the bending amount of the joint portion 4 in the product is defined. investigated. In addition, each of the left and right joint portions 4 was used as individual data. The results of this survey are shown in FIG. From FIG. 8, it can be seen that the bending amount of the joint portion 4 can be arranged even with the temperature difference ΔT. In the case of this data, the range of the temperature difference ΔT that satisfies the bending amount of the joint portion 4 within about ± 4 mm is 30 to 50 ° C.

このように、継手部４の曲がり量が上記の残留応力差Δσ、温度差ΔＴの双方で整理できるのは、図９に示すように、ΔＴとΔσにほぼ線形となる相関関係があるためである。したがって、温度差ΔＴと切断をした後の切断面端部の曲がり量との関係を定めておき、この関係に基づき前記曲がり量を許容値内とできるΔＴの範囲が得られるように、仕上げ圧延時に継手部４の冷却を行うことで、継手部４の曲がり量を抑制することができる。あるいは、温度差ΔＴとΔσとの関係を定めておき、この関係に基づき残留応力差Δσが0MPa以上60MPa以下となるΔＴの範囲が得られるように仕上げ圧延機１３の最終孔型Ｋ１での圧延において前記継手部４の冷却を行うことでも、継手部４の曲がり量を抑制することができる。 In this way, the amount of bending of the joint portion 4 can be arranged by both the above-mentioned residual stress difference Δσ and temperature difference ΔT because, as shown in FIG. 9, ΔT and Δσ have a substantially linear correlation. is there. Therefore, the relationship between the temperature difference ΔT and the bending amount at the end of the cut surface after cutting is determined, and based on this relationship, finish rolling is performed so that the range of ΔT that allows the bending amount to be within the allowable value can be obtained. By sometimes cooling the joint portion 4, the amount of bending of the joint portion 4 can be suppressed. Alternatively, the relationship between the temperature difference ΔT and Δσ is determined, and based on this relationship, rolling in the final hole type K1 of the finish rolling mill 13 is obtained so that the range of ΔT at which the residual stress difference Δσ is 0 MPa or more and 60 MPa or less can be obtained. The bending amount of the joint portion 4 can also be suppressed by cooling the joint portion 4 in the above.

なお、温度差ΔＴは、熱間圧延を終了後、すなわち、仕上げ圧延機１３の最終孔型Ｋ１での圧延を終了した後、ウェブ部２が５００℃まで温度降下するまでの間の同一時点におけるフランジ部３の最低温度Ｔfと継手部４ないし腕部５の最高温度Ｔgとの差とする。温度差ΔＴをフランジ部３の最低温度Ｔfと継手部４ないし腕部５の最高温度Ｔgとの差とするのは、継手部４の最高温度とフランジ部３の最低温度Ｔｆとの差のみを、曲がりを抑制できる範囲としたとしても、腕部５の最高温度とフランジ部３の最低温度Ｔｆとの差が曲がりを抑制できない範囲である場合には、曲がりを抑制できなくなるからである。また、温度差ΔＴを熱間圧延終了後、すなわち、仕上げ圧延機１３の最終孔型Ｋ１での圧延を終了した後、ウェブ部２が５００℃まで温度降下するまでの間の同一時点における温度差としたのは、ハット形鋼矢板１の温度がある程度以下にまで下がった後、具体的にはウェブ部２の温度で５００℃未満にまで下がった後の段階では、既に曲がりを発生させる程の残留応力差を発生させてしまっているためである。つまり、ウェブ部２の温度で５００℃以上の段階における温度差ΔＴを調整しないと、残留応力差Δσを変化させることはできず、曲がり抑制にも寄与しないためである。 The temperature difference ΔT is at the same time point after the hot rolling is completed, that is, after the rolling in the final hole type K1 of the finish rolling mill 13 is completed and until the temperature of the web portion 2 drops to 500 ° C. It is the difference between the minimum temperature Tf of the flange portion 3 and the maximum temperature Tg of the joint portion 4 or the arm portion 5. The temperature difference ΔT is the difference between the minimum temperature Tf of the flange portion 3 and the maximum temperature Tg of the joint portion 4 or the arm portion 5, only the difference between the maximum temperature of the joint portion 4 and the minimum temperature Tf of the flange portion 3. This is because even if the range is set so that the bending can be suppressed, if the difference between the maximum temperature of the arm portion 5 and the minimum temperature Tf of the flange portion 3 is within the range where the bending cannot be suppressed, the bending cannot be suppressed. Further, the temperature difference ΔT at the same time point after the hot rolling is completed, that is, after the rolling in the final hole type K1 of the finish rolling mill 13 is completed and the temperature of the web portion 2 drops to 500 ° C. The reason for this is that after the temperature of the hat-shaped steel sheet pile 1 has dropped to a certain level or less, specifically, after the temperature of the web portion 2 has dropped to less than 500 ° C, bending has already occurred. This is because a residual stress difference has been generated. That is, unless the temperature difference ΔT at the stage of 500 ° C. or higher is adjusted at the temperature of the web portion 2, the residual stress difference Δσ cannot be changed and does not contribute to bending suppression.

また、図５に示した結果から、温度差ΔＴは、継手部４の冷却を強めると小さくなる。よって、継手部冷却ヘッダー２５ａに供給する単位時間あたりの冷却水の流量Ｑをある程度まで大きくすれば、温度差ΔＴは小さくなる。しかし、上述のとおり圧延速度Ｖによって同じ流量Ｑでも継手部４の冷却能力は異なってくるため、圧延速度Ｖに応じて冷却水の流量Ｑを変化させるとよい。具体的には冷却水の流量Ｑを圧延速度Ｖで除したＱ／ＶでΔＴを整理できることがわかった。したがってＱ／ＶとΔＴの関係を予め求めておき、Ｑ／Ｖを変化させることでΔＴを調整することが好ましい。圧延速度Ｖの変化がないか、あっても同じ流量ＱであるときのΔＴへの影響があまり大きくない場合には、圧延速度Ｖを考慮せずに流量Ｑのみを変化させてΔＴを調整するようにしてもよい。 Further, from the results shown in FIG. 5, the temperature difference ΔT becomes smaller as the cooling of the joint portion 4 is strengthened. Therefore, if the flow rate Q of the cooling water supplied to the joint portion cooling header 25a per unit time is increased to some extent, the temperature difference ΔT becomes small. However, as described above, since the cooling capacity of the joint portion 4 differs depending on the rolling speed V even if the flow rate Q is the same, it is preferable to change the flow rate Q of the cooling water according to the rolling speed V. Specifically, it was found that ΔT can be arranged by Q / V obtained by dividing the flow rate Q of the cooling water by the rolling speed V. Therefore, it is preferable to obtain the relationship between Q / V and ΔT in advance and adjust ΔT by changing Q / V. If there is no change in the rolling speed V, or if the effect on ΔT is not so large when the flow rate Q is the same, then only the flow rate Q is changed without considering the rolling speed V to adjust ΔT. You may do so.

温度差ΔＴを調整する方法の場合は、上述した温度計３１を用いて仕上げ圧延後のハット形鋼矢板１の全幅方向の温度プロフィルを測定し、その測定結果から、次材の仕上げ圧延時に目標とするΔＴを達成できるように、冷媒の流量Ｑを補正するようにすることもできる。このようにすることで、圧延本数を重ねる毎に温度差ΔＴの制御精度が向上し、曲がり量をより抑制することができる。 In the case of the method of adjusting the temperature difference ΔT, the temperature profile in the entire width direction of the hat-shaped steel sheet pile 1 after finish rolling is measured using the thermometer 31 described above, and the measurement result is used as a target at the time of finish rolling of the next material. It is also possible to correct the flow rate Q of the refrigerant so that ΔT can be achieved. By doing so, the control accuracy of the temperature difference ΔT is improved each time the number of rolled rolls is increased, and the amount of bending can be further suppressed.

次に上記の知見から継手部４の変形抑止を簡便な方法で実用化できる、本発明のハット形鋼矢板１の製造方法の実施形態について説明する。図３、図４に示した設備を用いて、仕上げ圧延で種々の冷却条件を適用し、得られた各製品の継手部４の曲がり量を調査した。この調査結果の一例を図１０に示す．冷媒として水を用い，継手部４の冷却水流量Ｑ（リットル／秒）をＫ１孔型での仕上げ圧延速度Ｖ（ｍ／秒）で除したＱ／Ｖで継手部４の曲がり量を整理できることが判明した。 Next, an embodiment of the method for manufacturing the hat-shaped steel sheet pile 1 of the present invention will be described, which can practically suppress the deformation of the joint portion 4 from the above findings by a simple method. Using the equipment shown in FIGS. 3 and 4, various cooling conditions were applied in finish rolling, and the amount of bending of the joint portion 4 of each obtained product was investigated. An example of this survey result is shown in Fig. 10. Using water as the refrigerant, the bending amount of the joint 4 can be arranged by Q / V obtained by dividing the cooling water flow rate Q (liter / sec) of the joint 4 by the finishing rolling speed V (m / sec) of the K1 hole type. There was found.

圧延速度は、上述のとおり圧延の噛み込み時に定常部よりも速くするほか，圧延での製品の曲がりの発生有無や焼付き等の疵の発生有無で調整が行われる。したがって、この冷却水の単位時間あたりの流量Ｑを仕上げ圧延速度Ｖで除した値Ｑ／Ｖと切断面端部における継手部４の曲がり量との関係を定め、この関係から，継手部４の曲がり量が許容範囲になるＱ／Ｖの範囲を設定し、圧延速度Ｖの変化に対応させて、Ｑ／Ｖを一定値範囲に収めるように冷却水流量Ｑを調整することで継手部４の変形量を許容内に収めることができる。 As described above, the rolling speed is made faster than the stationary portion at the time of biting in rolling, and is adjusted by the presence or absence of bending of the product in rolling and the presence or absence of defects such as seizure. Therefore, the relationship between the value Q / V obtained by dividing the flow rate Q per unit time of the cooling water by the finish rolling speed V and the bending amount of the joint portion 4 at the end of the cut surface is determined, and from this relationship, the joint portion 4 By setting the range of Q / V where the bending amount becomes the allowable range and adjusting the cooling water flow rate Q so that the Q / V is kept within a certain value range in response to the change of the rolling speed V, the joint portion 4 The amount of deformation can be kept within the allowable range.

左側の継手部４と右側の継手部４、ウェブ部２の面の冷媒（本実施形態では冷却水）の流量は、それぞれ個別に設定することができる。ハット形鋼矢板１の継手形状は，図１１（ｂ）に示すように左右で非対称な形状であるため、左右の継手部４で温度差が生じやすいが、左右の継手部４の冷却水流量を個別に設定することで、一方の継手部４のみの変形が問題になる場合にも対応が可能となる。ウェブ部２の面の冷却が必要となるのは、上述したとおり、圧延後のＣＢ（クーリングベッド）上での自然冷却時の反りを防止する必要性がある場合である。よって、ウェブ部２の面の冷媒の流量を継手部４の冷媒の流量とは独立して設定可能とすることで、継手部４の曲がり抑制のための継手部４の冷却水流量とは関係なく、反りの発生の有無、程度により設定することができる。 The flow rates of the refrigerant (cooling water in this embodiment) on the surfaces of the left joint portion 4, the right joint portion 4, and the web portion 2 can be set individually. As shown in FIG. 11B, the joint shape of the hat-shaped steel sheet pile 1 is asymmetrical on the left and right sides, so that a temperature difference is likely to occur between the left and right joint parts 4, but the cooling water flow rate of the left and right joint parts 4 By setting individually, it is possible to deal with the case where deformation of only one joint portion 4 becomes a problem. As described above, the surface of the web portion 2 needs to be cooled when it is necessary to prevent warpage during natural cooling on the CB (cooling bed) after rolling. Therefore, by making it possible to set the flow rate of the refrigerant on the surface of the web portion 2 independently of the flow rate of the refrigerant in the joint portion 4, it is related to the cooling water flow rate of the joint portion 4 for suppressing the bending of the joint portion 4. It can be set depending on the presence or absence and degree of warpage.

このウェブ部２の面の冷却は、製品長が例えば１５ｍ以上と長い場合に有効となる。図１３は、ハット形鋼矢板１に上反りが発生している状態を示す模式図である。図１３に示すとおり、ある製品長のハット形鋼矢板１の長手方向両端のウェブ２の上面を結ぶ直線を基準直線とし、この基準直線から長手方向中央のウェブ２の上面に垂線をおろしたとき、この垂線上における基準直線とウェブ２の上面との距離を、その製品長での反り量Ｓと定義する。反り量Ｓは、製品長の２乗にほぼ比例して大きくなるので、同じ製造条件で製造した場合でも、製品長２０ｍのハット形鋼矢板１のＣＢ（クーリングベッド）上での反り量は、製品長１０ｍのハット形鋼矢板１のＣＢ（クーリングベッド）上での反り量の約４倍と、非常に大きくなる。 The cooling of the surface of the web portion 2 is effective when the product length is as long as 15 m or more, for example. FIG. 13 is a schematic view showing a state in which the hat-shaped steel sheet pile 1 is warped upward. As shown in FIG. 13, when a straight line connecting the upper surfaces of the webs 2 at both ends in the longitudinal direction of a hat-shaped steel sheet pile 1 having a certain product length is used as a reference straight line, and a perpendicular line is drawn from this reference straight line to the upper surface of the web 2 in the center in the longitudinal direction. The distance between the reference straight line on this perpendicular line and the upper surface of the web 2 is defined as the amount of warpage S at the product length. Since the amount of warpage S increases almost in proportion to the square of the product length, the amount of warpage of the hat-shaped steel sheet pile 1 having a product length of 20 m on the CB (cooling bed) is large even when manufactured under the same manufacturing conditions. The amount of warpage of the hat-shaped steel sheet pile 1 having a product length of 10 m on the CB (cooling bed) is about four times as large as that of the product.

図３、図４に示した設備を用いて、製品長が２０ｍとなるハット形鋼矢板２５Ｈを製造するにあたり、仕上げ圧延で冷媒として水を用いて種々のウェブ部冷却条件を適用し、得られた各製品の反り量Ｓを調査した。その結果、図１４に示すように、ウェブ部２への冷却水流量Ｑｗ（リットル／秒）をＫ１孔型での仕上げ圧延速度Ｖ（ｍ／秒）で除したＱｗ／Ｖで反り量Ｓを整理できることが判明した。この関係から、反り量Ｓが許容範囲となるＱｗ／Ｖの範囲ないし条件を設定することができる。
なお、以上説明した実施形態の全てにおいて、冷媒には水を用いたが、他の冷媒を用いることもできる。 In manufacturing the hat-shaped steel sheet pile 25H having a product length of 20 m using the equipment shown in FIGS. 3 and 4, various web part cooling conditions were applied by using water as a refrigerant in finish rolling. The amount of warpage S of each product was investigated. As a result, as shown in FIG. 14, the warp amount S is calculated by Qw / V obtained by dividing the cooling water flow rate Qw (liter / sec) to the web portion 2 by the finish rolling speed V (m / sec) in the K1 hole type. It turned out that it could be organized. From this relationship, it is possible to set a range or condition of Qw / V in which the warp amount S is an allowable range.
In all of the above-described embodiments, water is used as the refrigerant, but other refrigerants can also be used.

また、圧延後のハット形鋼矢板１を常温にまで自然冷却するＣＢ（冷却床）にて、継手部４の曲がりを確認し、継手部４の曲がり量が大きすぎる場合（＋4ｍｍを超える場合）は、後続の圧延材に対し冷却水流量を増やす、圧延速度を遅くする、あるいはこの両者を行う、という方法で継手部４の曲がり量を制御することもできる。逆に、継手部４の曲がり量が小さすぎる（＝内側に縮んでいる）場合は、継手部４の冷却水流量を減じる、圧延速度を速くする、といった制御を行うことができる。 Further, in the CB (cooling bed) where the rolled hat-shaped steel sheet pile 1 is naturally cooled to room temperature, the bending of the joint portion 4 is confirmed, and the bending amount of the joint portion 4 is too large (when it exceeds +4 mm). Can also control the bending amount of the joint portion 4 by increasing the flow rate of cooling water with respect to the subsequent rolled material, slowing down the rolling speed, or performing both. On the contrary, when the bending amount of the joint portion 4 is too small (= shrunk inward), it is possible to perform control such as reducing the cooling water flow rate of the joint portion 4 and increasing the rolling speed.

＜実施形態の効果＞
（１）本発明の一態様に係るハット形鋼矢板１は、ウェブ部２、フランジ部３、腕部５および継手部４から構成されるハット形鋼矢板１であり、継手部４ないし腕部５の残留応力最大値σgとフランジ部３の残留応力最小値σfとの差である残留応力差Δσ（＝σg−σf）が0MPa以上60MPa以下であることを特徴とする。
上記（１）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量を、継手嵌合に問題のない程度とすることができる。 <Effect of embodiment>
(1) The hat-shaped steel sheet pile 1 according to one aspect of the present invention is a hat-shaped steel sheet pile 1 composed of a web portion 2, a flange portion 3, an arm portion 5, and a joint portion 4, and is a joint portion 4 to an arm portion. The residual stress difference Δσ (= σg−σf), which is the difference between the maximum residual stress value σg of 5 and the minimum residual stress value σf of the flange portion 3, is 0 MPa or more and 60 MPa or less.
According to the configuration of (1) above, the amount of bending of the cut surface end portion after cutting the hat-shaped steel sheet pile 1 along the width direction can be set to a degree that does not cause a problem in fitting the joint.

（２）本発明の一態様に係るハット形鋼矢板１の製造方法は、ウェブ部２、フランジ部３、腕部５および継手部４から構成されるハット形鋼矢板１を、熱間圧延により該ハット形鋼矢板１の形状に造形した後に、幅方向に切断するハット形鋼矢板１の製造方法において、前記熱間圧延を終了後、前記ウェブ部２が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部３の最低温度Ｔfと前記継手部４ないし前記腕部５の最高温度Ｔgとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）とし、該温度差ΔＴと前記切断をした後の切断面端部の曲がり量との関係を定めておき、この関係に基づき前記曲がり量を許容値内とできるΔＴの範囲が得られるように仕上げ圧延機１３の最終孔型Ｋ１での圧延において前記継手部４の冷却を行うことを特徴とする。
上記（２）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量が、継手嵌合に問題のない程度であるハット形鋼矢板１を製造できる。 (2) In the method for manufacturing the hat-shaped steel sheet pile 1 according to one aspect of the present invention, the hat-shaped steel sheet pile 1 composed of the web portion 2, the flange portion 3, the arm portion 5 and the joint portion 4 is hot-rolled. In the method for manufacturing a hat-shaped steel sheet pile 1 that is formed into the shape of the hat-shaped steel sheet pile 1 and then cut in the width direction, after the hot rolling is completed until the temperature of the web portion 2 drops to 500 ° C. The difference between the minimum temperature Tf of the flange portion 3 and the maximum temperature Tg of the joint portion 4 or the arm portion 5 at the same time point is defined as a temperature difference ΔT (= Tg−Tf), and the temperature difference ΔT and the cutting are performed. The relationship with the bending amount at the end of the cut surface after the rolling is determined, and based on this relationship, the final hole type K1 of the finishing rolling mill 13 is provided so that the range of ΔT that allows the bending amount to be within the allowable value can be obtained. It is characterized in that the joint portion 4 is cooled in rolling.
According to the configuration of (2) above, the hat-shaped steel sheet pile 1 has a bending amount at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction so that there is no problem in fitting the joint. Can be manufactured.

（３）本発明の一態様に係るハット形鋼矢板１の製造方法は、ウェブ部２、フランジ部３、腕部５および継手部４から構成されるハット形鋼矢板１を、熱間圧延により該ハット形鋼矢板１の形状に造形した後に、幅方向に切断するハット形鋼矢板１の製造方法において、前記熱間圧延を終了後、前記ウェブ部２が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部３の最低温度Ｔfと前記継手部４ないし前記腕部５の最高温度Ｔgとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）、継手部４ないし腕部５の残留応力最大値σgとフランジ部３の残留応力最小値σfとの差を残留応力差Δσ（＝σg−σf）とし、前記温度差ΔＴと前記残留応力差Δσとの関係を定めておき、この関係に基づき前記残留応力差Δσを0MPa以上60MPa以下とできるΔＴの範囲が得られるように仕上げ圧延機１３の最終孔型Ｋ１での圧延において前記継手部４の冷却を行うことを特徴とする。
上記（３）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量が、継手嵌合に問題のない程度であるハット形鋼矢板１を製造できる。 (3) In the method for manufacturing the hat-shaped steel sheet pile 1 according to one aspect of the present invention, the hat-shaped steel sheet pile 1 composed of the web portion 2, the flange portion 3, the arm portion 5 and the joint portion 4 is hot-rolled. In the method for manufacturing a hat-shaped steel sheet pile 1 that is formed into the shape of the hat-shaped steel sheet pile 1 and then cut in the width direction, after the hot rolling is completed until the temperature of the web portion 2 drops to 500 ° C. The difference between the minimum temperature Tf of the flange portion 3 and the maximum temperature Tg of the joint portion 4 or the arm portion 5 at the same time point is the temperature difference ΔT (= Tg−Tf), and the residual of the joint portion 4 to the arm portion 5. The difference between the maximum stress value σg and the minimum residual stress value σf of the flange portion 3 is defined as the residual stress difference Δσ (= σg−σf), and the relationship between the temperature difference ΔT and the residual stress difference Δσ is defined and this relationship is established. Based on the above, the joint portion 4 is cooled in rolling with the final hole type K1 of the finishing rolling mill 13 so that the range of ΔT that allows the residual stress difference Δσ to be 0 MPa or more and 60 MPa or less can be obtained.
According to the configuration of (3) above, the hat-shaped steel sheet pile 1 has a bending amount at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction so that there is no problem in fitting the joint. Can be manufactured.

（４）本発明の一態様に係るハット形鋼矢板の製造方法は、ウェブ部２、フランジ部３、腕部５および継手部４から構成されるハット形鋼矢板１を、熱間圧延により該ハット形鋼矢板１の形状に造形した後に、幅方向に切断するハット形鋼矢板１の製造方法において、仕上げ圧延機１３の最終孔型Ｋ１での圧延において前記継手部４を冷却し、該冷却を行う冷媒の単位時間あたりの流量Ｑを前記仕上げ圧延機１３による圧延の際の圧延速度Ｖで除した値Ｑ／Ｖと、前記切断した後の切断面端部の曲がり量との関係を予め定めておき、該関係から前記曲がり量が許容範囲内となる前記値Ｑ／Ｖの範囲を設定し、前記圧延速度Ｖの変化に対応させて前記値Ｑ／Ｖを前記設定した範囲に収めるように前記冷媒の単位時間当たりの流量Ｑを調整することを特徴とする。
上記（４）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量が、継手嵌合に問題のない程度であるハット形鋼矢板１を製造できる。 (4) In the method for manufacturing a hat-shaped steel sheet pile according to one aspect of the present invention, the hat-shaped steel sheet pile 1 composed of a web portion 2, a flange portion 3, an arm portion 5 and a joint portion 4 is hot-rolled. In the method for manufacturing the hat-shaped steel sheet pile 1 which is formed into the shape of the hat-shaped steel sheet pile 1 and then cut in the width direction, the joint portion 4 is cooled in rolling with the final hole type K1 of the finish rolling mill 13 and cooled. The relationship between the value Q / V obtained by dividing the flow rate Q per unit time of the refrigerant for which the above-mentioned is performed by the rolling speed V at the time of rolling by the finishing rolling mill 13 and the bending amount of the cut surface end portion after the cutting is obtained in advance. From the relationship, the range of the value Q / V at which the bending amount is within the permissible range is set, and the value Q / V is set within the set range in accordance with the change of the rolling speed V. It is characterized in that the flow rate Q of the refrigerant per unit time is adjusted.
According to the configuration of (4) above, the hat-shaped steel sheet pile 1 has a bending amount at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction so that there is no problem in fitting the joint. Can be manufactured.

（５）上記（２）乃至（４）のいずれかの構成において、前記継手部４の冷却を、左右の継手部４について個別に行うことを特徴とする。
ハット形鋼矢板１の継手形状は、左右で非対称な形状であるため、左右の継手部４で温度差が生じやすいが、上記（５）の構成によれば、左右の継手部４の冷却を個別に設定することで、一方の継手部４のみの変形が問題になる場合にも対応が可能となる。 (5) In any of the above configurations (2) to (4), the joint portion 4 is cooled individually for the left and right joint portions 4.
Since the joint shape of the hat-shaped steel sheet pile 1 is asymmetrical on the left and right, a temperature difference is likely to occur between the left and right joint portions 4. By setting them individually, it is possible to deal with the case where deformation of only one joint portion 4 becomes a problem.

（６）上記（２）乃至（５）のいずれかの構成において、前記継手部４の冷却に加えて、前記ウェブ部２の冷却を行うことを特徴とする。
上記（６）の構成によれば、ハット形鋼矢板１を圧延後にＣＢ（クーリングベッド）上で自然冷却する際に、ハット形鋼矢板１に上反りが発生することを抑制することができる。 (6) In any of the configurations (2) to (5) above, the web portion 2 is cooled in addition to the cooling of the joint portion 4.
According to the configuration (6) above, when the hat-shaped steel sheet pile 1 is naturally cooled on the CB (cooling bed) after rolling, it is possible to prevent the hat-shaped steel sheet pile 1 from being warped.

（７）本発明の一態様に係るハット形鋼矢板の製造設備は、ウェブ部２、フランジ部３、腕部５および継手部４から構成されるハット形鋼矢板１を、熱間圧延により該ハット形鋼矢板１の形状に造形する熱間圧延機（粗圧延機１１、中間圧延機１２、及び仕上げ圧延機１３）と、該熱間圧延により得られたハット形鋼矢板１を幅方向に切断する鋸断装置（熱間鋸断装置１４）とを有するハット形鋼矢板１の製造設備において、前記熱間圧延機の仕上げ圧延機１３のガイド（前面ガイド２３）内に前記継手部４を冷却する継手部冷却装置２５を備え、該継手部冷却装置２５は前記継手部４を冷却する冷媒の単位時間あたりの流量Ｑを調整可能であり、前記仕上げ圧延機１３は圧延速度Ｖを調整可能であり、前記流量Ｑと圧延速度Ｖの実績を記録する記録手段を有することを特徴とする。
上記（７）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量に影響を及ぼす、継手部４を冷却する冷媒の流量Ｑ、仕上げ圧延機１３の圧延速度Ｖを調整可能であり、また、流量Ｑと圧延速度Ｖの実績を記録できるため、鋸断装置で切断面端部の曲がり量と、流量Ｑ、圧延速度Ｖの関係から最適な圧延速度、流量Ｑを見出すことが可能となる。 (7) In the hat-shaped steel sheet pile manufacturing equipment according to one aspect of the present invention, the hat-shaped steel sheet pile 1 composed of the web portion 2, the flange portion 3, the arm portion 5 and the joint portion 4 is hot-rolled. A hot rolling mill (rough rolling mill 11, intermediate rolling mill 12, and finish rolling mill 13) that forms the shape of the hat-shaped steel sheet pile 1 and a hat-shaped steel sheet pile 1 obtained by the hot rolling are placed in the width direction. In the manufacturing equipment of the hat-shaped steel sheet pile 1 having the saw cutting device (hot saw cutting device 14) for cutting, the joint portion 4 is placed in the guide (front guide 23) of the finish rolling mill 13 of the hot rolling mill. A joint portion cooling device 25 for cooling is provided, the joint portion cooling device 25 can adjust the flow rate Q of the refrigerant for cooling the joint portion 4 per unit time, and the finish rolling mill 13 can adjust the rolling speed V. It is characterized by having a recording means for recording the actual results of the flow rate Q and the rolling speed V.
According to the configuration (7) above, the flow rate Q of the refrigerant that cools the joint portion 4 and the finish rolling, which affect the amount of bending at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction. Since the rolling speed V of the machine 13 can be adjusted and the actual results of the flow rate Q and the rolling speed V can be recorded, the sawing device is optimal from the relationship between the bending amount at the end of the cut surface, the flow rate Q, and the rolling speed V. It is possible to find a suitable rolling speed and flow rate Q.

（８）上記（７）の構成において、前記熱間圧延を終了後、前記ウェブ部２が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部３の最低温度Ｔfと前記継手部４ないし前記腕部５の最高温度Ｔgとの差である温度差ΔＴ（＝Ｔｇ−Ｔｆ）を、予め設定された許容値内とするように前記継手部冷却装置２５からの冷媒の単位時間当たりの流量Ｑを設定する流量制御手段を備えたことを特徴とする。
上記（８）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量が、継手嵌合に問題のない程度であるハット形鋼矢板１を製造できる。 (8) In the configuration of (7) above, the minimum temperature Tf of the flange portion 3 and the joint portion at the same time point between the completion of the hot rolling and the temperature drop of the web portion 2 to 500 ° C. Per unit time of the refrigerant from the joint cooling device 25 so that the temperature difference ΔT (= Tg−Tf), which is the difference from the maximum temperature Tg of 4 to the arm 5, is within a preset allowable value. It is characterized by being provided with a flow rate control means for setting the flow rate Q of the above.
According to the configuration of (8) above, the hat-shaped steel sheet pile 1 has a bending amount at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction so that there is no problem in fitting the joint. Can be manufactured.

（９）上記（８）の構成において、前記仕上げ圧延機１３の下流側で、前記ウェブ部２が５００℃まで温度降下する位置よりも上流側に、前記ハット形鋼矢板１の全幅方向の温度分布を測定する温度計３１を有し、前記流量制御手段は、該温度計３１による温度分布測定結果にもとづき、次材の仕上げ圧延時に前記冷媒の流量Ｑを補正することを特徴とする。
上記（９）の構成によれば、圧延本数を重ねる毎にΔＴの制御精度が向上し、より継手嵌合に問題のない程度であるハット形鋼矢板１を製造できるようになる。 (9) In the configuration of (8) above, the temperature of the hat-shaped steel sheet pile 1 in the entire width direction on the downstream side of the finish rolling mill 13 and upstream of the position where the temperature of the web portion 2 drops to 500 ° C. The flow control means includes a thermometer 31 for measuring the distribution, and the flow control means corrects the flow rate Q of the refrigerant at the time of finish rolling of the next material based on the temperature distribution measurement result by the thermometer 31.
According to the configuration of (9) above, the control accuracy of ΔT is improved each time the number of rolled sheets is increased, and the hat-shaped steel sheet pile 1 can be manufactured to the extent that there is no problem in fitting the joint.

（１０）上記（７）の構成において、前記流量Ｑを前記圧延速度Ｖで除した値Ｑ／Ｖと、前記切断した後の切断面端部の曲がり量との関係から、前記曲がり量が許容範囲内となる前記値Ｑ／Ｖの範囲が予め設定され、前記圧延速度Ｖの変化に対応させて前記値Ｑ／Ｖを前記設定した範囲に収めるように前記冷媒の単位時間当たりの流量Ｑを調整する流量制御手段を有することを特徴とする。
上記（１０）の構成によれば、ハット形鋼矢板１を幅方向に沿って切断した後の切断面端部の曲がり量が、継手嵌合に問題のない程度であるハット形鋼矢板１を製造できる。 (10) In the configuration of (7) above, the bending amount is permissible from the relationship between the value Q / V obtained by dividing the flow rate Q by the rolling speed V and the bending amount at the end of the cut surface after cutting. The range of the value Q / V within the range is set in advance, and the flow rate Q per unit time of the refrigerant is set so as to keep the value Q / V within the set range in response to the change in the rolling speed V. It is characterized by having a flow rate control means for adjusting.
According to the configuration of (10) above, the hat-shaped steel sheet pile 1 has a bending amount at the end of the cut surface after cutting the hat-shaped steel sheet pile 1 along the width direction so that there is no problem in fitting the joint. Can be manufactured.

（１１）上記（７）乃至（１０）の構成において、前記ガイド（前面ガイド２３）内に、前記継手部冷却装置２５に加えて、ウェブ部２を冷却するウェブ部冷却装置２６を有することを特徴とする。
上記（１１）の構成によれば、ハット形鋼矢板１を圧延後にＣＢ（クーリングベッド）上で自然冷却する際の上反り発生を抑制したハット形鋼矢板１を製造することができる。 (11) In the configurations (7) to (10), the guide (front guide 23) includes a web portion cooling device 26 for cooling the web portion 2 in addition to the joint portion cooling device 25. It is a feature.
According to the configuration (11) above, it is possible to manufacture the hat-shaped steel sheet pile 1 in which the occurrence of upward warpage when the hat-shaped steel sheet pile 1 is naturally cooled on the CB (cooling bed) after rolling is suppressed.

＜実施例１＞
図１，図２，図３，図４に示したハット形鋼矢板の圧延製造ラインにて、ウェブ厚が10.8mm，有効幅が900mmであるハット形鋼矢板１０Ｈの製造を実施した。
熱間鋸断装置（ホットソー）１４の前面に温度計３１を配置し、この温度計３１にて仕上げ圧延後のハット形鋼矢板１の幅方向の温度分布を測定し、適合例では、継手部４の最高温度とフランジ部３の最低温度との差ΔＴの目標を、温度差ΔＴと継手部４の曲がり量との関係から設定した。具体的には、図８に示す温度差ΔＴと継手部４の曲がり量との関係から、曲がり量を許容値（±４ｍｍ）内とできるΔＴの範囲として目標値40℃、目標範囲30〜50℃と設定し、Ｋ１孔型での仕上げ圧延の際に、継手部冷却水流量を左右それぞれで個別に調整した。一方、比較例では、継手部冷却をまったく実施しないケース（比較例１）と、最大流量で冷却するケース（比較例２）を実施した。温度プロフィルは熱間鋸断装置１４で鋸断時の時間経過とともに、時々刻々変化するので、ウェブ部２の最高温度が550℃時点の温度プロフィルから温度差ΔＴを算出した．なお、すべてのケースで仕上げ圧延速度は2ｍ／ｓである。 <Example 1>
At the rolling production line of the hat-shaped steel sheet piles shown in FIGS. 1, 2, 3 and 4, the hat-shaped steel sheet pile 10H having a web thickness of 10.8 mm and an effective width of 900 mm was manufactured.
A thermometer 31 is placed in front of the hot saw cutting device (hot saw) 14, and the temperature distribution in the width direction of the hat-shaped steel sheet pile 1 after finish rolling is measured with this thermometer 31, and in the applicable example, the joint portion. The target of the difference ΔT between the maximum temperature of 4 and the minimum temperature of the flange portion 3 was set from the relationship between the temperature difference ΔT and the bending amount of the joint portion 4. Specifically, based on the relationship between the temperature difference ΔT shown in FIG. 8 and the bending amount of the joint portion 4, the target value is 40 ° C. and the target range is 30 to 50 as the range of ΔT that allows the bending amount to be within the allowable value (± 4 mm). The temperature was set to ℃, and the flow rate of the cooling water at the joint was adjusted individually on the left and right sides during the finish rolling in the K1 hole type. On the other hand, in the comparative example, a case where the joint portion was not cooled at all (Comparative Example 1) and a case where the joint portion was cooled at the maximum flow rate (Comparative Example 2) were carried out. Since the temperature profile changes from moment to moment with the passage of time during sawing with the hot sawing device 14, the temperature difference ΔT was calculated from the temperature profile when the maximum temperature of the web portion 2 was 550 ° C. The finish rolling speed is 2 m / s in all cases.

このように製造したハット形鋼矢板１について、冷却床ＣＢにて常温まで自然冷却を行い、その後にレベラー矯正を行った後、製品の長手中央で冷間鋸断を行い、この切断面端部の変形量を調査するとともに、残留応力も調査した。この結果を表１にまとめて示す。 The hat-shaped steel sheet pile 1 manufactured in this way is naturally cooled to room temperature on the cooling bed CB, then leveler straightened, and then cold sawed at the center of the longitudinal direction of the product. In addition to investigating the amount of deformation of the steel, the residual stress was also investigated. The results are summarized in Table 1.

Figure 0006828722
Figure 0006828722

表１の結果から、継手部４の最高温度とフランジ部３の最低温度との差ΔＴの目標を、温度差ΔＴと継手部の曲がり量との関係から設定し、温度差ΔＴがこの目標に従うように継手部４の冷却を施した適合例では、継手部４の曲がり量が左右の継手部４ともに±４ｍｍ以内となっている。一方、比較例１および比較例２では、継手部４の冷却水流量が不適正であるため、継手部４の曲がり量が±４ｍｍ以内を満足しなかった。 From the results in Table 1, the target of the difference ΔT between the maximum temperature of the joint portion 4 and the minimum temperature of the flange portion 3 is set from the relationship between the temperature difference ΔT and the bending amount of the joint portion, and the temperature difference ΔT follows this target. In the conforming example in which the joint portion 4 is cooled as described above, the bending amount of the joint portion 4 is within ± 4 mm for both the left and right joint portions 4. On the other hand, in Comparative Example 1 and Comparative Example 2, since the cooling water flow rate of the joint portion 4 was improper, the bending amount of the joint portion 4 was not satisfied within ± 4 mm.

＜実施例２＞
次に、図１、図２、図３、図４に示したハット形鋼矢板１の圧延製造ラインにて、ウェブ厚が13.2mm、有効幅が900mmであるハット形鋼矢板２５Ｈの製造を実施した。本実施例では、適合例、比較例とも圧延素材を５本ずつ用意し、仕上げ最終圧延であるＫ１孔型での圧延における圧延速度を圧延素材ごとに1.0〜4.0ｍ／ｓの間で変化させていった。継手冷却水流量Ｑを圧延速度Ｖで除した値（Ｑ／Ｖ）は図１０から目標値2.0（Ｌ／s）／（ｍ/ｓ）、許容範囲1.6〜2.4とし、素材毎の仕上げ圧延速度の変化とともに、冷却水流量を調整した場合（適合例）と、仕上げ圧延速度の変化によらず冷却水流量を一定とした場合（比較例）で圧延を実施した。
これらの製品について、熱間鋸断された製品端部の継手部曲がり量を調査した。この結果を表２に示す。 <Example 2>
Next, at the rolling production line of the hat-shaped steel sheet pile 1 shown in FIGS. 1, 2, 3, and 4, the hat-shaped steel sheet pile 25H having a web thickness of 13.2 mm and an effective width of 900 mm was manufactured. did. In this embodiment, five rolling materials are prepared for each of the conforming examples and the comparative examples, and the rolling speed in the K1 hole type rolling, which is the final final rolling, is changed between 1.0 and 4.0 m / s for each rolling material. I went. The value (Q / V) obtained by dividing the joint cooling water flow rate Q by the rolling speed V is a target value of 2.0 (L / s) / (m / s) and an allowable range of 1.6 to 2.4 from FIG. 10, and the finish rolling speed for each material. Rolling was carried out when the cooling water flow rate was adjusted (suitable example) and when the cooling water flow rate was kept constant regardless of the change in the finish rolling speed (comparative example).
For these products, the amount of bending of the joint at the end of the product that was hot sawed was investigated. The results are shown in Table 2.

Figure 0006828722
Figure 0006828722

表２の結果から、図１０に示したＱ／Ｖの値と継手部４の曲がり量との関係から、継手部４の曲がり量を±４ｍｍ以内できるように、Ｑ／Ｖの目標値を2.0、許容範囲を1.6〜2.4を許容範囲として継手部４の冷却水流量を調整した適合例では、いずれの仕上げ圧延速度条件においても、継手部４の曲がり量が±４ｍｍ以内となっていることがわかる。一方、仕上げ圧延速度Ｖによらず継手部４の冷却水流量を一定とした比較例では、仕上げ圧延速度条件によっては、継手部４の曲がり量が±４ｍｍ以内であるものもあるが（Ｖ＝2.0ｍ／ｓの場合）、仕上げ圧延速度の変化により継手部４の曲がり量が±４ｍｍ以内を達成できない場合があることがわかる。 From the results in Table 2, from the relationship between the Q / V value shown in FIG. 10 and the bending amount of the joint portion 4, the target value of Q / V is set to 2.0 so that the bending amount of the joint portion 4 can be within ± 4 mm. In the conforming example in which the cooling water flow rate of the joint portion 4 is adjusted with the allowable range of 1.6 to 2.4, the bending amount of the joint portion 4 is within ± 4 mm under any finish rolling speed condition. Understand. On the other hand, in the comparative example in which the cooling water flow rate of the joint portion 4 is constant regardless of the finish rolling speed V, the bending amount of the joint portion 4 may be within ± 4 mm depending on the finish rolling speed condition (V =). (In the case of 2.0 m / s), it can be seen that the bending amount of the joint portion 4 may not be achieved within ± 4 mm due to changes in the finish rolling speed.

＜実施例３＞
図１、図２、図３、図４に示したハット形鋼矢板１の圧延製造ラインにて、ウェブ厚が１３．２ｍｍ、有効幅が９００ｍｍであるハット形鋼矢板２５Ｈのうち製品長が２０ｍとなる長尺製品の製造を実施した。製造にあたっては、仕上げ最終圧延であるＫ１孔型での圧延における圧延速度を２．０ｍ／ｓ、継手冷却水量Ｑを圧延速度Ｖで除した値（Ｑ／Ｖ）を２．０（Ｌ／ｓ）／（ｍ／ｓ）とした。そして、ウェブ冷却水量Ｑｗを４．０（Ｌ／ｓ）としてウェブ冷却を行った場合と、ウェブ冷却を行わなかった場合とについて、それぞれ３本ずつ製造した。 <Example 3>
In the rolling production line of the hat-shaped steel sheet pile 1 shown in FIGS. 1, 2, 3 and 4, the product length of the hat-shaped steel sheet pile 25H having a web thickness of 13.2 mm and an effective width of 900 mm is 20 m. We carried out the production of long products. In the production, the rolling speed in the K1 hole type rolling, which is the final finishing rolling, is 2.0 m / s, and the value (Q / V) obtained by dividing the joint cooling water amount Q by the rolling speed V is 2.0 (L / s). ) / (M / s). Then, three bottles were produced for each of the case where the web cooling was performed with the web cooling water amount Qw set to 4.0 (L / s) and the case where the web cooling was not performed.

この結果、ウェブ冷却を行って製造した製品３本、ウェブ冷却を行わずに製造した製品３本、いずれも継手部４の曲がり量は±４ｍｍ以内を満足していた。一方で、ウェブ冷却を行った場合は３本の製品ともにＣＢ上での反り量は５０ｍｍ以下で特に問題はなかったのに対し、ウェブ冷却を行わなかった場合には３本の製品ともに反り量Ｓが２００ｍｍ以上と非常に大きくなり、ＣＢでの製品搬送において製品の斜行が発生し、隣り合う製品との接触および重なりが生じた。このため、ウェブ冷却を行わなかった製品については、オペレータが天井クレーンを使用して、ＣＢ上での搬送状態を修正する作業が発生し、その間の製造のピッチダウンが生じた。 As a result, the bending amount of the joint portion 4 was satisfied within ± 4 mm in all of the three products manufactured by web cooling and the three products manufactured without web cooling. On the other hand, when web cooling was performed, the amount of warpage on the CB was 50 mm or less for all three products, and there was no particular problem, whereas when web cooling was not performed, the amount of warpage for all three products was 50 mm or less. The S became very large, 200 mm or more, and the product was skewed during product transportation in the CB, and contact and overlap with adjacent products occurred. For this reason, for products that have not been web-cooled, the operator has to use an overhead crane to correct the transport state on the CB, and the manufacturing pitch has been reduced during that time.

１ ハット形鋼矢板
２ ウェブ部
３ フランジ部
４ 継手部
５ 腕部
１０ 加熱炉
１１ 粗圧延機（熱間圧延機）
１２ 中間圧延機（熱間圧延機）
１３ 仕上げ圧延機（熱間圧延機）
１３ａ ミルモータ
１４ 熱間鋸断装置（鋸断装置：ホットソーＨＳ）
２１ 上圧延ロール
２２ 下圧延ロール
２３ 前面ガイド（ガイド）
２３ａ 上ガイド
２３ｂ 下ガイド
２４ 後面ガイド
２５ 継手部冷却装置
２５ａ 継手部冷却ヘッダー
２５ｂ 継手部冷却ノズル
２５ｅ 流量調整弁（継手部冷却水流量調整弁）
２６ ウェブ部冷却装置
２６ａ ウェブ上面冷却ヘッダー
２６ｂ ウェブ上面冷却ノズル
２６ｃ ウェブ下面冷却ヘッダー
２６ｄ ウェブ下面冷却ノズル
２６ｅ 流量調整弁（ウェブ上面冷却水流量調整弁）
２９ 冷却水ポンプ
３０ 演算装置（流量制御手段）
３１ 温度計 1 Hat-shaped steel sheet pile 2 Web part 3 Flange part 4 Joint part 5 Arm part 10 Heating furnace 11 Rough rolling mill (hot rolling mill)
12 Intermediate rolling mill (hot rolling mill)
13 Finishing rolling mill (hot rolling mill)
13a Mill motor 14 Hot sawing device (saw cutting device: hot saw HS)
21 Top rolling roll 22 Bottom rolling roll 23 Front guide (guide)
23a Upper guide 23b Lower guide 24 Rear guide 25 Joint cooling device 25a Joint cooling header 25b Joint cooling nozzle 25e Flow adjustment valve (joint cooling water flow adjustment valve)
26 Web part cooling device 26a Web top surface cooling header 26b Web top surface cooling nozzle 26c Web bottom surface cooling header 26d Web bottom surface cooling nozzle 26e Flow control valve (Web top surface cooling water flow rate adjustment valve)
29 Cooling water pump 30 Arithmetic logic unit (flow control means)
31 thermometer

Claims (4)

ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板であり、
前記継手部ないし前記腕部の残留応力最大値σgと前記フランジ部の残留応力最小値σfとの差である残留応力差Δσ（＝σg−σf）が0MPa以上60MPa以下であり、
前記継手部ないし前記腕部の残留応力最大値σgは、前記ハット形鋼矢板の幅方向に沿って１００ｍｍ当たり均等に４点あるいは５点測定して得られた前記ハット形鋼矢板の長手方向残留応力の幅方向分布から算出される前記継手部ないし前記腕部の残留応力の最大値であり、
前記フランジ部の残留応力最小値σfは、前記ハット形鋼矢板の幅方向に沿って１００ｍｍ当たり均等に４点あるいは５点測定して得られた前記ハット形鋼矢板の長手方向残留応力の幅方向分布から算出される前記フランジ部の残留応力の最小値であることを特徴とするハット形鋼矢板。 A hat-shaped steel sheet pile composed of a web part, a flange part, an arm part and a joint part.
The residual stress difference Δσ (= σg−σf), which is the difference between the maximum residual stress value σg of the joint portion or the arm portion and the minimum residual stress value σf of the flange portion, is 0 MPa or more and 60 MPa or less.
The maximum residual stress value σg of the joint portion or the arm portion is the residual in the longitudinal direction of the hat-shaped steel sheet pile obtained by measuring 4 or 5 points evenly per 100 mm along the width direction of the hat-shaped steel sheet pile. It is the maximum value of the residual stress of the joint portion or the arm portion calculated from the distribution of the stress in the width direction.
The minimum residual stress value σf of the flange portion is the width direction of the longitudinal residual stress of the hat-shaped steel sheet pile obtained by measuring 4 or 5 points evenly per 100 mm along the width direction of the hat-shaped steel sheet pile. A hat-shaped steel sheet pile, which is the minimum value of the residual stress of the flange portion calculated from the distribution. ウェブ部、フランジ部、腕部および継手部から構成されるハット形鋼矢板を、熱間圧延により該ハット形鋼矢板の形状に造形した後に、幅方向に切断するハット形鋼矢板の製造方法において、
前記熱間圧延を終了後、前記ウェブ部が５００℃まで温度降下するまでの間の同一時点における、前記フランジ部の最低温度Ｔfと前記継手部ないし前記腕部の最高温度Ｔgとの差を温度差ΔＴ（＝Ｔｇ−Ｔｆ）、前記継手部ないし前記腕部の残留応力最大値σgと前記フランジ部の残留応力最小値σfとの差を残留応力差Δσ（＝σg−σf）とし、前記温度差ΔＴと前記残留応力差Δσとの関係を定めておき、この関係に基づき前記残留応力差Δσを0MPa以上60MPa以下とできるΔＴの範囲が得られるように仕上げ圧延機の最終孔型での圧延において前記継手部の冷却を行うものであり、
前記継手部ないし前記腕部の残留応力最大値σgは、前記ハット形鋼矢板の幅方向に沿って１００ｍｍ当たり均等に４点あるいは５点測定して得られた前記ハット形鋼矢板の長手方向残留応力の幅方向分布から算出される前記継手部ないし前記腕部の残留応力の最大値であり、
前記フランジ部の残留応力最小値σfは、前記ハット形鋼矢板の幅方向に沿って１００ｍｍ当たり均等に４点あるいは５点測定して得られた前記ハット形鋼矢板の長手方向残留応力の幅方向分布から算出される前記フランジ部の残留応力の最小値であることを特徴とするハット形鋼矢板の製造方法。 In a method for manufacturing a hat-shaped steel sheet pile, which is formed by hot rolling a hat-shaped steel sheet pile composed of a web portion, a flange portion, an arm portion, and a joint portion into the shape of the hat-shaped steel sheet pile, and then cut in the width direction. ,
The difference between the minimum temperature Tf of the flange portion and the maximum temperature Tg of the joint portion or the arm portion at the same time point after the completion of the hot rolling until the temperature of the web portion drops to 500 ° C. is the temperature. The difference ΔT (= Tg−Tf), the difference between the maximum residual stress value σg of the joint or the arm and the minimum residual stress σf of the flange is defined as the residual stress difference Δσ (= σg−σf), and the temperature. The relationship between the difference ΔT and the residual stress difference Δσ is determined, and based on this relationship, rolling in the final hole type of the finishing rolling mill so that the range of ΔT that allows the residual stress difference Δσ to be 0 MPa or more and 60 MPa or less can be obtained. To cool the joint portion in
The maximum residual stress value σg of the joint portion or the arm portion is the residual in the longitudinal direction of the hat-shaped steel sheet pile obtained by measuring 4 or 5 points evenly per 100 mm along the width direction of the hat-shaped steel sheet pile. It is the maximum value of the residual stress of the joint portion or the arm portion calculated from the distribution of the stress in the width direction.
The minimum residual stress value σf of the flange portion is the width direction of the longitudinal residual stress of the hat-shaped steel sheet pile obtained by measuring 4 or 5 points evenly per 100 mm along the width direction of the hat-shaped steel sheet pile. A method for manufacturing a hat-shaped steel sheet pile, which is a minimum value of residual stress of the flange portion calculated from the distribution. 前記継手部の冷却を、左右の継手部について個別に行うことを特徴とする請求項２に記載のハット形鋼矢板の製造方法。 The method for manufacturing a hat-shaped steel sheet pile according to claim 2, wherein the joint portions are cooled individually for the left and right joint portions. 前記継手部の冷却に加えて、前記ウェブ部の冷却を行うことを特徴とする請求項２又は３に記載のハット形鋼矢板の製造方法。 The method for manufacturing a hat-shaped steel sheet pile according to claim 2 or 3, wherein the web portion is cooled in addition to cooling the joint portion.
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