JP3660745B2 - Manufacturing method of differential steel sheet pile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for the preparation of different thickness steel sheet piles for use in the construction sector, in particular, to a method for manufacturing a different thickness sheet piles having a plate thickness difference at the central portion and the end portion in the width direction.
[0002]
[Prior art]
Conventionally, steel sheet piles used in the construction field include a U-type double-claw type and a Lanzel type from the viewpoint of its shape. ), Straight type, arch type (including standard arch type and leap arch type), box type, and pipe type steel sheet piles. Each of the above-mentioned steel sheet piles is manufactured by hot rolling from a beam blank, or by hot rolling from a narrow bloom to a wide steel sheet pile with a tooth shape. However, when manufacturing a steel sheet pile by hot rolling, there is a problem that the forming capacity is large but the equipment cost is enormous, and it takes a considerable amount of time for roll recombination including upper claw forming, and the sheet pile width is large. There is a limit to the production of steel sheet piles exceeding 600 mm to 800 mm, and a sheet pile width larger than that is considered to be unmanufacturable at present due to the limitations of the rolling mill. Also, in the forming by hot rolling, if the plate thickness of the flange and the end is greatly different, the steel sheet pile will be deformed due to the difference in cooling rate in the cooling process after forming, so the plate thickness of the flange and end There is a problem that must be made almost uniform. On the other hand, some small steel sheet piles are manufactured by cold forming instead of hot rolling, but the equipment cost is low, but there is a problem that the forming ability is small due to the cold forming. Further, in the case of this cold forming, it is difficult to form the joint portion unless the plate thickness is 10 mm or less. That is, when the plate thickness is large, the shape of the joint portion becomes excessively large, the amount of cold plastic strain is large, and bending forming becomes difficult and cracking is likely to occur.
[0003]
In addition to the actual situation described above, these steel sheet piles have become common sense in the manufacture of steel sheet piles having a substantially uniform thickness in the longitudinal direction and width direction of the steel sheet, and the sheet thickness design of the steel sheet pile according to the required section modulus is It was not done. However, from the viewpoint of an effective section modulus, it has been found that the section factor greatly contributes to the flange portion, and the web portion does not require that much section. That is, there has been no idea that the flange portion where a large section modulus needs to function effectively has a thick plate thickness, and the web portion that functions sufficiently with a small section modulus may have a small plate thickness.
[0004]
If this concept is extended, the concept of using a differential steel sheet will naturally appear. However, in the field of the thick steel sheet to which the differential steel sheet belongs, most of the examples as seen in many prior examples such as Japanese Patent Publication No. 63-66601. Has been developed differential thickness steel plate with a plate thickness difference in the longitudinal direction of the steel plate, or a plate thickness step in the middle portion of the steel plate longitudinal direction, most of its purposes are shipbuilding materials, liquid and gas storage tank materials, The use for pillars and wall materials of large buildings is extremely limited. Japanese Patent Publication No. 5-13002 discloses a differential thickness steel sheet in which a thickness difference is provided in the width direction of the steel sheet. In other words, the above publication discloses a method for producing a variety of different thickness steel plates in the plate width direction such as one type of upper and lower caliber shapes in the steel plate width direction, for example, corrugations and uneven shapes, the purpose of which is to use the amount of steel plate used. The use is considered to be out of the range of the conventional category.
[0005]
As described above, in the conventional steel sheet pile, the useless cross-sectional area in the web part and the joint part that do not contribute to the bending cross-sectional performance is large, and therefore the amount of steel used is inevitably large, and if the sheet thickness increases, It was difficult to form joints on both sides having a large bending curvature.
[0006]
[Problems to be solved by the invention]
As a result of various studies on the shape of steel sheet piles from the viewpoint of the section modulus, the present inventors have found that the flange portion that needs to function effectively has a large plate thickness, and the web portion that functions sufficiently with a small section modulus. Then, based on the knowledge that sheet thickness may be thin, the manufacturing method of the steel sheet pile by a difference thickness steel plate, especially the difference thickness steel plate which has a plate thickness difference in a sheet width direction is provided.
[0007]
[Means for Solving the Problems]
That is, the present invention is a method for manufacturing a differential thickness steel sheet pile that is cold-formed using a differential thickness steel sheet having a thickness difference in the width direction, and the steel sheet pile is thick at the center in the width direction, both ends. This is a method of manufacturing a differential thickness steel sheet pile that is cold-formed using a symmetric differential thickness steel sheet that gradually decreases in thickness, and further, a corrosion resistant coating is provided on the surface, or the differential thickness steel sheet pile itself is usually used. This is a method for producing a differential thickness steel sheet pile using clad steel plates of steel and titanium or ordinary steel and stainless steel.
[0008]
Further, the manufacturing method of the differential thickness steel sheet pile according to the present invention is to manufacture the right and left target differential plate steel plates by hot rolling, where the central portion is thick in the width direction and the thickness gradually decreases toward both ends, and then cold forming. Thus, the thick plate portion is used as a flange portion, and both end portions where the plate thickness is gradually reduced are formed into a joint portion. In addition, as a specific manufacturing method, in the hot rolling step, a rolling roll having a vertically symmetrical drum-shaped caliber that forms a recess from the end toward the center in the width direction, or a lower roll having a flat shape And rolling with a rolling roll having a drum-shaped caliber that forms a recess from the end to the center in the width direction, the center is thicker in the width direction, and the plate thickness increases toward both ends. The difference thickness steel plate of the left and right objects to be gradually reduced is manufactured by hot rolling, and then the thick part of the plate thickness is used as a flange portion by cold forming, and both end portions of the gradually decreasing plate thickness are used as joint portions. It is a manufacturing method of the difference thickness steel sheet pile which shape | molds and shape | molds.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the differential thickness steel sheet pile manufactured by the manufacturing method configured as described above, it is possible to exhibit effective cross-sectional performance as a steel sheet pile because a steel sheet with an equal thickness is not used as in the past. In addition, from the viewpoint of manufacturing, it is possible to increase the plate thickness at a portion where the cold forming amount is small, and to reduce the plate thickness at a portion where the cold forming amount is large, such as a joint portion. In particular, a cold-formed steel sheet pile using a steel plate with a thick central portion generally increases the thickness of the portion that most contributes to the cross-sectional performance, and greatly contributes to the cross-sectional performance as a steel sheet pile. Moreover, a steel plate edge part is located in the joint part vicinity as a steel sheet pile, and contributes little to cross-sectional performance improvement, and it becomes economical, so that plate | board thickness is small. On the other hand, from the viewpoint of manufacturing, when a steel plate having a thick central portion is a cold-formed steel sheet pile, it is generally a portion with a small amount of cold forming and does not hinder manufacturing. Moreover, a steel plate edge part contacts the joint part of a steel sheet pile, and the one where plate | board thickness is small becomes easy. As described above, the present invention is a result of pursuing effective cross-sectional performance by adopting a cross-sectional plate thickness distribution that is easy to cold form, and a wide steel sheet pile having a sheet pile width exceeding 600 mm to 800 mm can be freely formed, and the plate A reasonable plate thickness can be arranged in the width direction, the cross-sectional performance per steel weight can be increased, and even a small and strong joint can be easily formed. Furthermore, the present invention can remarkably improve the production yield and can greatly reduce the amount of steel used.
[0010]
In the steel sheet pile, normally corrode in order to be placed in the soil or water being staked into the soil, also significantly even corrosion in locations exposed to sea water, in order to maintain the sheet pile performance long It took a great deal of cost for the corrosion protection measures to be taken. In the manufacturing method of the differential thickness steel sheet pile of the present invention, it is possible to easily improve the corrosion resistance by applying galvanization, thermal spraying of corrosion resistant metal and various coatings on the surface. More generally, it is possible to remarkably improve the corrosion resistance by coating a resin film such as polyethylene or polyurethane with several hundred μm, for example, 2-3 μm.
[0011]
Furthermore, when the corrosion resistance imparting treatment is omitted and it is desired to ensure the corrosion resistance of the steel material itself, a clad steel plate that is well known at present, for example, stainless steel and ordinary steel, or titanium material and ordinary steel on one side or Corrosion resistance can be sufficiently maintained by using a double-sided clad steel plate.
[0012]
【Example】
<Embodiment 1> An embodiment of the present invention will be described in detail with reference to the drawings by taking a U-shaped steel sheet pile (material JISA-5528) as an example. FIG. 1 is a perspective view of a conventional steel sheet pile shape. (A) is a steel sheet pile having a substantially uniform thickness manufactured by conventional hot rolling, and (b) is a conventional cold sheet pile. A steel sheet pile having a uniform sheet thickness produced by hot forming, and (c) shows a steel sheet pile shape when the sheet thickness is increased in conventional cold forming.
[0013]
In the above-described conventional steel sheet pile, in the case of the steel sheet pile (a) manufactured by hot rolling, the plate thickness in the width direction, that is, the plate thickness of the flange portion and the web portion is substantially uniform, and the sheet pile width is 600 mm. It was limited to a small size of ˜800 mm or less, and it was difficult to produce a steel sheet pile having a larger size. In the case of (b) formed by cold forming, as in (a), the plate thickness in the width direction, that is, the plate thickness of the flange portion and the web portion is uniform, and the plate is formed because of cold forming. The thickness is limited to 10 mm or less. For this reason, the section modulus does not work effectively, and particularly the steel material of the joint is wasteful. Furthermore, in the case of (c) in which the plate thickness is increased in order to increase the section modulus, the shape of the joint portion becomes excessively large, and the amount of plastic strain during cold forming becomes large, making bending forming difficult. Cracking occurred.
[0014]
FIG. 2 shows a differential thickness steel sheet pile according to the manufacturing method of the present invention. FIG. 2 (a) shows a hot rolling process for a slab, bloom or sheet bar. As shown in FIG. 2 (b), a symmetric drum-shaped caliber that forms a recess from the end to the center in the width direction. Or a lower roll having a flat shape and a rolling roll having a drum-shaped caliber that forms a recess from the end toward the center in the width direction. The difference thickness steel plate of the right-and-left object which a plate | board thickness reduces gradually as it goes to both ends is manufactured.
[0015]
In this case, the obtained differential thickness steel plate may be a drum-shaped differential thickness steel plate with a middle portion at the center, or may be a mountain-shaped difference thickness steel plate having a flat bottom surface and a bulge on the top surface portion. . A hot rolled differential thickness steel plate having a plate width of 1800 mm, a maximum center plate thickness of 25 mm, a minimum plate thickness of both ends: 7 mm, and a length of 15 m in the plate width direction was obtained by hot rolling. As shown in FIG. 2 (c), the hot-rolled differential thickness steel plate obtained in this way is used as a flange portion as shown in FIG. 2 (c), and both end portions where the thickness is gradually reduced are joints. A U-shaped differential thickness steel sheet pile having a size of sheet pile width: 800 mm, sheet pile height: 300 mm, circular claw portion diameter: 20 mm, and length: 15 m was produced.
[0016]
In the manufacturing method of the differential thickness steel sheet pile according to the present invention, it is possible to manufacture a differential thickness steel sheet pile having a wide flange exceeding 600 mm, and a rational sheet thickness arrangement corresponding to the required section modulus is obtained. The cross-sectional performance of the joint is greatly improved, and a small and strong joint can be easily formed by cold forming. Moreover, since the thickness of the steel sheet pile width direction end portion was reduced, the amount of steel used per unit could be reduced by about 30% on average. <Example 2> In accordance with the manufacturing method of Example 1 above, a clad steel sheet having a 2 mm stainless steel layer in the surface layer part, and a U-type differential thickness steel sheet pile by cold forming from a clad steel sheet having a 1 mm titanium layer in the surface layer part Manufactured. The corrosion resistance of each of these U-shaped differential thickness steel sheet piles was compared with a conventional U-shaped steel sheet pile without surface coating and piled on the seawater coastal area. As a result, in the conventional U-type steel sheet pile having a uniform thickness, rust is generated due to tides, especially in the non-uniform thickness area at the center of the flange, and further crack propagation occurs from that point. On the other hand, in the case of the U-type differential thickness steel sheet pile made of the clad steel according to the present invention and the U-type differential thickness steel sheet pile with a polyethylene coating on the surface, no rust is generated even when exposed to seawater and tides for a long time. Was not recognized.
[0017]
【The invention's effect】
As described above, the manufacturing method of the differential thickness steel sheet pile according to the present invention enables rational plate thickness arrangement, has an excellent effect on the cross-sectional performance per steel weight, and further greatly reduces the amount of steel used. There is an effect that can be done. Moreover, it has the great effect that the wide steel sheet pile conventionally made difficult can be manufactured easily.
[Brief description of the drawings]
FIG. 1 is a perspective view of a conventional steel sheet pile shape, (a) is a steel sheet pile having a uniform thickness produced by conventional hot rolling, and (b) is A steel sheet pile having a uniform sheet thickness manufactured by conventional cold forming, (c) shows a steel sheet pile shape when the sheet thickness is increased in conventional cold forming.
FIG. 2 shows a differential thickness steel sheet pile according to the manufacturing method of the present invention, in which (a) is a perspective view showing the shape of the differential thickness steel sheet obtained after hot rolling, and (b) is ( The front view which shows the roll caliber for obtaining the difference thickness steel plate shown to a), (C) is a perspective view of this invention U type difference thickness steel sheet pile.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Flange part 2 ... Web part 3 ... Claw part 4 ... Differential thickness steel plate

Claims (4)

In the width direction, a symmetric differential plate steel plate having a thick central portion and gradually decreasing as it goes to both ends is manufactured by hot rolling, and then the thick portion is used as a flange portion by cold forming, and A method for producing a differential thickness steel sheet pile, characterized by forming and shaping so that both end portions where the plate thickness is gradually decreased are joint portions. The method for producing a differential thickness steel sheet pile according to claim 1, wherein a corrosion-resistant coating is applied to the surface of the differential pressure steel sheet pile. The method for producing a differential thickness steel sheet pile according to claim 1 or 2, wherein the differential pressure steel sheet is a plain steel and titanium, or a clad steel sheet of ordinary steel and stainless steel.   In the hot rolling step, a rolling roll having a symmetrical drum caliber that forms a recess from the end to the center in the width direction, or a lower roll having a flat shape and from the end to the center in the width direction Rolling with a rolling roll that is combined with a rolling roll having a drum-shaped caliber that forms a concave portion facing the opposite side, heats the difference thickness steel plate for the left and right objects, where the central part is thick in the width direction and the thickness gradually decreases toward both ends. It is manufactured by cold rolling, and then shaped by shaping by cold forming to use the thick part as a flange part, and to form both end parts where the thickness is gradually reduced as joint parts. The manufacturing method of the difference thickness steel sheet pile.

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