JP7082322B2 - Manufacturing method and manufacturing equipment for hat-shaped steel sheet piles - Google Patents

Description

The present invention particularly relates to a method and equipment for manufacturing a hat-shaped steel sheet pile having a large cross section.

Conventionally, steel sheet piles having joints at both ends, such as a hat type, have been manufactured by a hole rolling method. As a general process of this hole rolling method, first, a steel material (rectangular material) heated to a predetermined temperature in a heating furnace is rolled in order by a rough rolling machine having a hole type, an intermediate rolling machine and a finishing rolling machine. It is known to do. Further, rolling by a rough rolling machine, an intermediate rolling machine and a finish rolling machine is also referred to as rough rolling, intermediate rolling and finish rolling, respectively, and these rollings are also collectively referred to as modeling rolling.

As a hole-type rolling method, for example, in Patent Document 1, a plurality of hole-types are engraved on a roll in rough rolling, intermediate rolling, and finish rolling, and each of these hole-types is rolled by 1 to 2 passes to perform a hat-shaped steel sheet pile. The technology for manufacturing is disclosed.

Further, in Patent Document 2, a hole type is configured so that the stretch balance between the web and the flange is maintained in the manufacture of the U-shaped steel sheet pile, and the material to be rolled is reciprocated a plurality of times in the same hole type for rolling. The technology is disclosed.

Further, Patent Document 3 describes the production of a steel sheet pile having a flange, in which the rolling material to be rolled in the rough rolling step and the intermediate rolling step is performed by a plurality of pass rolling in a plurality of continuous hole molds, and a plurality of rolls are performed. In rolling with a hole type, in two consecutive hole types, the flange corresponding part is under predetermined conditions so that the flange reduction rate near the rolling neutral line is smaller than the total flange reduction rate in the hole type in the subsequent stage. A technique for forming a roll gap and performing rolling is disclosed.

In this way, in the shaping and rolling of hat-shaped steel sheet piles, the material is rolled with the hole mold (caliber) formed in the rolling rolls of each rolling mill, and the cross-sectional shape of the material is gradually shaped to the desired product shape. However, in the large-section hat-shaped steel sheet pile, which has a higher overall height than the conventional hat-shaped steel sheet pile, the hole-shaped molding height is further increased.

Japanese Unexamined Patent Publication No. 2006-88176 Japanese Unexamined Patent Publication No. 60-44101 Japanese Unexamined Patent Publication No. 2019-38014

However, the above-mentioned conventional technique still has the following problems to be solved.
In the conventional hole-type rolling method exemplified in Patent Document 1, in the rough rolling, intermediate rolling process to finish rolling process, the flange is in a linear state at almost the same angle as the product, and the one-hole type rolls in 1 to 2 passes. However, especially when the flange width is large and the plate thickness is thin, when reverse rolling is performed, the stretching balance of each part in the cross section may not be achieved and a flange wave may occur.

Further, in the technique described in Patent Document 2, when rolling is performed such that a large steel sheet pile having a large flange width and a thin flange thickness, such as a hat-shaped steel sheet pile, is stretched to a large extent. In addition, even if the balance of stretching described in Patent Document 2 is maintained, shape defects such as flange waves may occur, stable rolling and molding may be difficult, and product shape defects may occur. Further, within the restrictions of the rolling mill, it may not be possible to realize appropriate equilibrium conditions for suppressing the occurrence of shape defects such as flange waves.

Further, the technique described in Patent Document 3 is effective for preventing flange waves, but in the case of a hat-shaped steel sheet pile having a large cross section, it is difficult to secure the wall thickness of the arm and the joint portion unless the flange stretching is reduced. There was a problem that could not be a solution. In recent years, steel sheet piles with a large width and a thin plate thickness with a large cross section have been required from the viewpoint of economy and workability, and the actual situation is that further improvement of technology is required in the manufacture of such large steel sheet piles. Is.

The present invention has been made in view of the above circumstances, and an object thereof is to manufacture a hat-shaped steel sheet pile having a larger flange width and a thinner flange thickness than the conventional one, such as a hat-shaped steel sheet pile having a large cross section. In some cases, a hat type that can suppress the occurrence of shape defects such as flange waves and insufficient wall thickness of arms and joints during modeling and rolling in the manufacturing process, and can improve product dimensional accuracy and rolling stability. The purpose is to propose a manufacturing method for steel sheet piles, and to provide manufacturing equipment suitable for that method.

In the method for manufacturing a hat-shaped steel sheet pile according to the present invention, which has been developed to solve the above problems and realize the above-mentioned object, the material to be rolled is subjected to rough rolling, intermediate rolling and finish rolling to manufacture a hat-shaped steel sheet pile. How to do
The rolling of the material to be rolled in the rough rolling step, the intermediate rolling step and the finish rolling step is performed by multi-pass rolling in a plurality of hole molds.
In the rolling with the plurality of hole types, in at least two hole types, the front hole type has a flange thickness from the vicinity of the rolling neutral line of the flange corresponding portion to the vicinity of the web shoulder, and from the vicinity of the rolling neutral line to the vicinity of the arm base. Thicker than near the rolling neutral line,
The latter-stage hole type is characterized in that the flange-corresponding portion having a thicker flange is rolled so as to be strongly compressed.
Here, the "near the rolling neutral line" is a flange-corresponding portion crossing the neutral line in the hole type, and is hereinafter referred to as "near the rolling neutral line".

The method for manufacturing the hat-shaped steel sheet pile according to the present invention is described.
a. The flange reduction rate (%) in the vicinity of the web shoulder and the vicinity of the base of the arm in the latter-stage hole type is set to a strong reduction rate of 2% or more and 8% or less as compared with the vicinity of the rolling neutral line. Here, the flange reduction rate (%) is used. , The percentage obtained by dividing the difference between the flange thickness before rolling and the flange thickness after rolling in the rolling by the flange thickness before rolling.
b. In the front hole type, the thickening of the flange near the web shoulder is applied by projecting to the outside of the facing flange, and the thickening of the flange near the base of the arm is applied by projecting to the inside of the facing flange.
Can be a more preferred solution.

The hat-shaped steel sheet pile manufacturing equipment according to the present invention developed to solve the above-mentioned problems and realize the above-mentioned object manufactures a hat-shaped steel sheet pile including a rough rolling mill, an intermediate rolling mill and a finish rolling mill. It is a manufacturing facility for
Each rolling mill has a hole mold, and the rough rolling mill, the intermediate rolling mill, and the finish rolling mill are arranged so that the material to be rolled is sequentially rolled by the hole mold.
In at least two hole types, the pre-stage hole type is such that the flange thickness from the vicinity of the rolling neutral line to the vicinity of the web shoulder of the flange corresponding portion and from the vicinity of the rolling neutral line to the vicinity of the arm base is thicker than that near the rolling neutral line. Is configured in
The latter-stage hole type is characterized in that the flange-corresponding portion having a thicker flange thickness is configured to be strongly compressed from the vicinity of the rolling neutral line.

According to the method for manufacturing a hat-shaped steel sheet pile of the present invention, when a hat-shaped steel sheet pile having a large cross section is manufactured by multi-pass rolling in a plurality of hole types, the front-stage hole type is formed from the vicinity of the rolling neutral line of the flange corresponding portion. The flange thickness up to the vicinity of the web shoulder and from the vicinity of the rolling neutral line to the vicinity of the arm base is made thicker than the vicinity of the rolling neutral line, and in the rear hole type, the flange corresponding portion with the thickened flange thickness is strongly pressed down. Therefore, by generating a width expansion due to rolling, it has an effect of helping the flange to be stretched in the hole shape, and it is possible to solve the shortage of the wall portion of the arm portion and the joint portion. Further, by setting the rolling reduction ratio of the flange portion in the vicinity of the thickened web shoulder and the vicinity of the arm base within a specific range, the rolling can be performed efficiently. In addition, the effective roll diameter can be secured and the roll strength can be improved.

Furthermore, by specifying the thickening position of the flange near the shoulder of the web and near the base of the arm, it becomes possible to suppress the wobbling of the material to be rolled and the misalignment of the joint portion by suppressing the web, and the rolling is stable. It is possible to improve the sex.

According to the hat-shaped steel sheet pile manufacturing equipment of the present invention, it is a manufacturing equipment for manufacturing a hat-shaped steel sheet pile including a rough rolling mill, an intermediate rolling mill and a finish rolling mill, and each rolling mill has a hole. It has a mold, and the rough rolling mill, the intermediate rolling mill, and the finishing rolling mill are arranged so that the material to be rolled is sequentially rolled by the hole mold. The mold is configured so that the flange thickness from the vicinity of the rolling neutral line to the vicinity of the web shoulder and from the vicinity of the rolling neutral line to the vicinity of the base of the arm of the flange corresponding portion is thicker than that near the rolling neutral line. Is configured so that the flange-corresponding portion having a thicker flange thickness is strongly compressed from the vicinity of the rolling neutral line. It is possible to solve the shortage of meat in the arms and joints.

It is a schematic explanatory drawing which shows the manufacturing equipment of a hat-shaped steel sheet pile. (A) and (b) represent the specifications of 10H and 25H in the schematic cross-sectional view of the conventional hat-shaped steel sheet pile, respectively, and (c) and (d) are the schematic cross-sectional views of the hat-shaped steel sheet pile having a large cross section of 45H, respectively. And represents the standard of 50H. It is schematic cross-sectional view of the hole shape of the pre-stage explaining the method of one Embodiment which concerns on this invention. It is a partially enlarged view of the part corresponding to the flange part which concerns on the said embodiment. (A) is a cross-sectional view for explaining the hole-shaped design concept of the conventional method, and (b) is a cross-sectional view for explaining the hole-shaped design concept according to the above embodiment. (A) is a side schematic view showing a state in which the material to be rolled is bitten into the rear hole type in the above embodiment, and (b) is a sectional view taken along the line DD'. (A) is a schematic cross-sectional view showing the state of filling of the joint portion at the time of post-stage hole type rolling by the conventional method, and (b) is a schematic cross-sectional view showing the state of filling of the joint portion at the time of post-stage hole type rolling according to the above embodiment. be. It is sectional drawing which shows the concept of the joint part meat amount shortage measures in the conventional method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the rolled material having a substantially hat-shaped steel sheet pile shape is described as being rolled in a posture in which the web is located above the flange (so-called inverted U posture), but the scope of application of the present invention is naturally other than that. It also extends to rolling in the posture of (for example, U posture).

Further, the material or the material S to be rolled described below indicates a long steel material to be rolled when a hat-shaped steel sheet pile product is manufactured, and the steel materials passed on the rolling line L are generically referred to. The material S to be rolled is referred to as a material S to be rolled, and the material S to be rolled in a state of being rolled down in each rolling mill is described by a different name as necessary. The material S to be rolled has a substantially hat-shaped shape, and includes a web-corresponding portion 6 which is a substantially horizontal portion and flange-corresponding portions 7 and 7'which are connected to both ends of the web-corresponding portion 6 at a predetermined angle. The arm corresponding parts 8 and 8'that are connected to the ends of the flange corresponding parts 7 and 7'that are different from the end connected to the web corresponding part 6 and the joint corresponding to the tips of the arm corresponding parts 8 and 8'. It is composed of parts 9 and 9'. The ends of the joint-corresponding portions 9 and 9'are referred to as claw portions 10 and 10', respectively.

First, the outline of the rolling line L, which is a basic configuration as the manufacturing equipment 1 for manufacturing the hat-shaped steel sheet pile, will be described. FIG. 1 is a rolling flow chart of a hat-shaped steel sheet pile. In FIG. 1, the rolling traveling direction of the rolling line L, that is, the transport direction of the material S to be rolled is the direction indicated by the arrow. The steel slab or the like, which is the material S heated in the heating furnace 2, is sequentially rolled by the rough rolling mill 3, the intermediate rolling mill 4, and the finish rolling mill 5. Further, rolling by the rough rolling mill 3, the intermediate rolling mill 4, and the finish rolling mill 5 is also referred to as rough rolling, intermediate rolling, and finish rolling, and these rollings are also collectively referred to as modeling rolling. Although not shown, 2 steps of rough rolling (8K, 7K), 4 steps of intermediate rolling (6K, 5K, 4K, 3K) and 2 steps of finish rolling (2K, 1K) are exemplified.

In the shaping and rolling of hat-shaped steel sheet piles, the material S is rolled with a hole mold (caliber) formed in the rolling rolls of each rolling mill, so that the cross-sectional shape of the material is gradually shaped and formed to the desired product shape. To go. As shown in FIG. 2, the large cross-section hat-shaped steel sheet piles 45H (c) and 50H (d), which have a higher overall height than the conventional hat-shaped steel sheet piles 10H (a) and 25H (b), have a hole-shaped molding height. The steel is even higher.

According to the study by the inventors, when manufacturing a hat-shaped steel sheet pile with a large cross section, the arm corresponding portions 8 and 8'are pushed down on the upper hole type roll 11 side in the molding rolling from the material and the front hole type finished material. On the prepared hole type roll 12 side, the flange corresponding parts 7 and 7'are bent and stretched by pushing up the web corresponding part 6, and the arm corresponding parts 8 and 8'and the joint corresponding parts 9 and 9'are made of the material to be rolled. Will be pulled in, and the amount of meat in the joint will be insufficient or fluctuate.

In particular, in the initial stage of each hole type rolling, the deformation becomes large, the rolling load tends to be excessive, and there are equipment restrictions such as the rolling mill, the effective roll diameter, and the strength, and it becomes difficult to deepen the hole type height. In some cases, the amount of stretching of the flange-corresponding portions 7 and 7'in the hole type in the next process must be increased more than the conventional amount.

Further, in actual rolling, the flange plate thickness does not become an overall uniform plate thickness according to the design standard due to the increase in the molding height, but the web-corresponding portion 6 and the arm-corresponding portion 8 are not obtained. , 8'The thickness of the flange-corresponding parts 7 and 7'near the connection part becomes thinner due to stretching, while the thickness of the flange-corresponding parts 7 and 7'near the rolling neutral line O is springback by rolling (returning). Thickness) causes a phenomenon that the finish is thicker than the design standard.

When the amount of extension of the flange corresponding parts 7 and 7'is large as described above, not only the arm corresponding parts 8 and 8'but also the joint corresponding parts 8 and 8'are pulled in the flange corresponding parts 7 and 7'direction. Not only cannot the required amount of meat be secured, but also the fluctuation of the rolled metal (meat) tends to increase.

Further, even if the thickness of the flange corresponding portion 7 and 7'near the connecting portion with the web corresponding portion 6 and the arm corresponding portion 8 and 8'becomes thin due to the stretching of the flange corresponding portion 7 and 7', the rolling neutral line O Since the thickness of the flange-corresponding parts 7 and 7'in the vicinity becomes thicker due to the thickening, the flange-corresponding parts 7 and 7'near the rolling neutral line O tend to be strongly reduced and cause flange waves even when the reduction balance is achieved by the rear hole type. It will be easier. As a countermeasure, Patent Document 3 shows that a roll gap of the flange corresponding portion is formed under predetermined conditions such that the flange reduction rate in the vicinity of the rolling neutral line becomes small, which is effective for preventing flange waves. However, unless the amount of extension of the flange-corresponding portions 7 and 7'is reduced, it is difficult to secure the wall amount of the arm-corresponding portions 8 and 8'and the joint-corresponding portions 9 and 9', and this is not a solution.

Therefore, in the present invention, first, in the pre-stage hole type, from the vicinity of the rolling neutral line O to the vicinity of the shoulder connected to the web corresponding portion 6, and from the vicinity of the rolling neutral line O to the vicinity of the base connecting to the arm corresponding portions 8 and 8'. The thickness of the flange-corresponding portions 7 and 7'up to the above is made thicker than the thickness of the flange-corresponding portions 7 and 7'near the rolling neutral line O. In particular, it is preferable to increase the thickening amount of the flange corresponding portions 7 and 7'as the distance from the vicinity of the rolling neutral line O increases. Further, it is preferable to arrange the maximum thickness immediately before the linear flange corresponding portions 7 and 7'turn toward the web corresponding portion 6 and the arm corresponding portions 8 and 8'. Next, in the rear hole type, from the vicinity of the rolling neutral line O of the flange corresponding portions 7 and 7', which is thickened in the flange corresponding portion 7 and 7'in the front hole type, to the vicinity of the shoulder connected to the web corresponding portion 6. , And, by strongly pressing down from the vicinity of the rolling neutral line O to the vicinity of the base connected to the arm corresponding parts 8 and 8', the wall amount of the arm corresponding parts 8 and 8'and the joint corresponding parts 9 and 9'is secured. It is a thing. It is preferable that the front hole type and the rear hole type described above are continuous, but one or two or more hole types having a uniform reduction rate of the flange-corresponding portion may be arranged between them.

FIG. 3 shows a concept of a hole type design according to an embodiment of the present invention in a cross-sectional view, and the periphery of the right flange corresponding portion 7 is enlarged and shown in FIG. Here, the conventional hole-shaped curve is shown by a two-dot chain line, and the hole-shaped curve according to the present invention is shown by a solid line. As shown in FIG. 4, the thickness A of the flange corresponding portion 7 near the shoulder connected to the web corresponding portion 6 and the thickness C of the flange corresponding portion 7 up to the vicinity of the base connected to the arm corresponding portion 8 are rolling neutral lines. It is thicker and thicker than the thickness B of the flange corresponding portion 7 in the vicinity of O. Further, in the example of FIG. 4, the thickness of the flange-corresponding portion 7 from the vicinity of the rolling neutral line O to the vicinity of the shoulder connected to the web-corresponding portion 6 and from the vicinity of the rolling neutral line O to the vicinity of the root connected to the arm-corresponding portion 8. The thickness is gradually made thicker than the thickness B of the flange corresponding portion 7 near the rolling neutral line O. The same applies to the facing flange-corresponding portion 7'.

In the example of FIG. 4, the thickening of the flange-corresponding portion 7 is added so as to project from the vicinity of the rolling neutral line O to the vicinity of the shoulder connected to the web-corresponding portion 6 to the outside of the flange-corresponding portion 7. The gap on the roll 11 side is wide. Further, from the vicinity of the rolling neutral line O to the vicinity of the base connected to the arm corresponding portion 8, the portion is overhanging and added to the inside of the facing flange corresponding portion 7, and the gap on the prepared hole type roll 12 side is widened.

Since the first shaped hole type (8K) in rough rolling is deformed from a steel slab having a rectangular cross section, which is the material S, the flange corresponding portions 7 and 7'are thickened based on the above design concept. It is preferable not to perform this, and it is preferable to add thickening of the flange corresponding portions 7 and 7'from the hole type (7K) which is the next molding. In addition, the hole type (1K), which is the final finish rolling, naturally does not have a thickening, and the final product shape is formed.

The thickening amount of the flange corresponding portion 7 near the shoulder connected to the web corresponding portion 6 and the thickening amount of the flange corresponding portion 7 near the base connected to the arm corresponding portion 8 are the maximum thickening amounts in the longitudinal direction of the flange corresponding portion 7. The ratio of the increased amount to the thickness of the flange corresponding portion 7 near the rolling neutral line O is expressed as a percentage, and δt (%) = (AB) / B × 100 = (CB) / B ×. 100 is defined as the thickening rate. It is more preferable that the thickening ratio δt of the flange corresponding portion 7 is gradually decreased from the rough rolled hole type (7K) to the finished rolled hole type (2K), and the rolled hole type immediately before the final finish ( In 2K), it is preferably 2% or more.

FIG. 5A shows the concept of the conventional hole type design by a two-dot chain line for the front hole type and a solid line for the rear hole type. Here, the rolling neutral lines of both hole types are matched by taking two continuous hole types before and after as an example. In the conventional method, the reduction ratio σA of the flange corresponding portion 7 and 7'near the shoulder connected to the web corresponding portion 6, the reduction ratio σB of the flange corresponding portion 7 and 7'near the rolling neutral line O, and the arm corresponding portion 8 and 8'. The rolling reduction ratios σC of the flange-corresponding portions 7 and 7'connected to the base were designed to be the same, that is, σA = σB = σC. In the hole type (solid line) in the latter stage, the flange corresponding portions 7 and 7'are stretched, so that the arm corresponding portions 8 and 8'and thus the joint corresponding portions 9 and 9'are to be pulled inward. Therefore, there is a shortage of meat in the arm-corresponding portions 8, 8'and by extension, the joint-corresponding portions 9, 9'. Here, the reduction ratio σ (%) of the flange-corresponding portion means a percentage obtained by dividing the difference between the flange thickness before reduction and the flange thickness after reduction in the rolling by the flange thickness before reduction.

FIG. 5B shows the concept of the hole type design according to the above embodiment by a two-dot chain line for the front hole type and a solid line for the rear hole type. Similar to FIG. 5A, the rolling neutral lines of both hole types are matched by taking two continuous hole types before and after as an example. In the present embodiment, the reduction ratio σA'of the flange corresponding portion 7 near the shoulder connected to the web corresponding portion 6 and the reduction ratio σC'of the flange corresponding portion 7 near the base connected to the arm corresponding portion 8 are in the vicinity of the rolling neutral line O. The rolling reduction ratio of the flange corresponding portion 7 of the above is larger than σB, that is, σA'> σB and σC'> σB. As described above, the portion where the flange thickness is increased is relatively strongly compressed. As a result, it is possible to prevent the arm-corresponding portions 8, 8'and the joint-corresponding portions 9, 9'from being pulled toward the flange-corresponding portions 7, 7'. Therefore, the arm-corresponding portions 8 and 8'and thus the joint-corresponding portions 9 and 9'could be sufficiently filled. The relationship between the thickening rate δt and the reduction rate σ of the flange-corresponding part is shown. If the thickening rate after rolling is δt2 and the flange thickness after K1 rolling is A1 = B1, the flange reduction rate near the web shoulder of the flange corresponding portion σA1 = (A2-A1) / A2 × 100 = ( B2 + δt2 / 100-B1) / (B2 + δt2 / 100) × 100, and the flange reduction rate near the rolling neutral line σB1 = (B2-B1) / B2 × 100, and the difference in flange reduction rate (σA1-σB1) = δt2. It becomes (B1 / A2). Since A2> B1, the difference in the flange reduction rate is a little smaller than the thickening rate.

The reduction ratio σA'of the flange corresponding portion 7 near the shoulder connected to the web corresponding portion 6 and the reduction ratio σC'of the flange corresponding portion 7 near the root connected to the arm corresponding portion 8 are the flange corresponding portion 7 near the rolling neutral line O. It is preferable that the rolling reduction is 2% or more and 8% or less from the rolling reduction ratio σB. If the upper limit is exceeded, deformation in the post-stage hole type, that is, compression deformation of the web-corresponding portion 6 and extrusion deformation of the arm-corresponding portion, may cause poor appearance in rolling, for example, deterioration of vertical warpage. On the other hand, if it is less than the lower limit, the effect of suppressing the pull-in of the arm-corresponding portion and the joint-corresponding portion due to the stretching of the flange portion 7 is hardly observed.

FIG. 6A shows, in the present embodiment, a state in which the material to be rolled is bitten into the rear hole type in a schematic side view. FIG. 6B is a cross-sectional view taken along the line DD'of FIG. 6A, showing a state in which the top portion of the web-corresponding portion 6 of the member S to be rolled is pressed against the rear-stage upper hole type roll 31. There is. As can be seen from FIG. 6B, the shoulder portion (solid line) of the web-corresponding portion 6 of the rolled member S in the present embodiment projects outward from the shoulder portion (dashed-dotted line) of the web-corresponding portion 6 of the conventional material. (Α), it is firmly restrained by the shoulder portion (broken line) of the web-corresponding portion 6 of the rear-stage upper hole type roll 31 so as not to cause rattling to the left or right. On the other hand, in the conventional material, since the web spreads outward when the web is rolled, a gap is created between the material S to be rolled and the post-stage upper hole type roll on the left and right shoulders of the web-corresponding portion 6, and there is a possibility that the material is displaced to the left and right and bites. .. Further, the root (solid line) in the vicinity of the arm portions 8 and 8'of the flange-corresponding portions 7 and 7'of the rolled member S in the present embodiment projects inward from that of the conventional material (dashed-dotted line) (γ). ), The gap between the material S to be rolled and the lower hole type roll 32 (broken line) in the latter stage is reduced, and it becomes easier to suppress the wobbling of the material to be rolled, which contributes to the stability of rolling.

FIG. 7 is a schematic cross-sectional view showing the state of molding and rolling of the material to be rolled by the post-stage hole type rolls 31 and 32. FIG. 7A shows the reduction ratio of the flange-corresponding portions 7 and 7'evenly from the shoulder portion connecting to the web-corresponding portion 6 to the base near the arm-corresponding portions 8 and 8'according to the conventional method (σA = σB = σC). Is shown. There is a gap between the joint corresponding parts 9 and 9'of the large cross-section hat-shaped steel sheet pile, especially the claws 10 and 10'of the material S to be rolled, and the flange corresponding parts 7 and 7'. The pull-in of the arm-corresponding portions 8 and 8'indicates that the meat amount of the joint-corresponding portions 9 and 9'is insufficient.

FIG. 7B shows the rolling reduction σA'of the flange-corresponding portion 7 near the shoulder connected to the web-corresponding portion 6 and the rolling down of the flange-corresponding portion 7 near the base connected to the arm-corresponding portion 8 by the method according to the present embodiment. The case where the ratio σC'is larger than the reduction ratio σB of the flange corresponding portion 7 near the rolling neutral line O (σA'> σB, σC'> σB) is shown. As a result, it can be seen that the arm-corresponding portions 8 and 8'are not pulled in even when the flange-corresponding portions 7 and 7'are stretched, and the joint-corresponding portions 9 and 9'are filled with the material S to be rolled.

In the conventional method, in order to solve the above-mentioned insufficient wall thickness of the joint-corresponding portion, it is necessary to design a higher flange-corresponding portion in the front-stage hole type roll. This concept is shown in FIG. 8 as a schematic cross-sectional view. The profiles of the pre-stage upper hole type roll and the previous stage lower hole type roll before improvement are shown by c1 and c2, respectively. On the other hand, the profiles of the front-stage upper hole type roll and the front stage lower hole type roll in which the flange height is increased as a measure to prevent the arm corresponding portion from being pulled in are shown in d1 and d2, respectively. When designed by the conventional method, the height of the hole type increases, so that the effective diameter becomes smaller in terms of using the roll, and the roll strength is also inferior. In the present embodiment, the wall thickness of the flange-corresponding portion is increased and the thickness of the flange-corresponding portion is increased without changing the hole height, so that the above-mentioned problems do not occur.

INDUSTRIAL APPLICABILITY The present invention is suitable for application to a situation in which the meat amount of the portion is insufficient by pulling in the portion to be connected due to the stretching of the flange-corresponding portion in the post-stage hole mold in the molding rolling using a plurality of hole-shaped rolls.

1 Manufacturing equipment 2 Heating furnace 3 Rough rolling mill 4 Intermediate rolling mill 5 Finish rolling mill 6 Web-corresponding part 7, 7'Flang-corresponding part 8, 8'Arm-corresponding part 9, 9'Joint-corresponding part 10, 10'Claw part 11 Upper hole type roll 12 Lower hole type roll 21 Previous stage upper hole type roll 22 Front stage lower hole type roll 31 Rear stage upper hole type roll 32 Rear stage lower hole type roll L Rolling line S Material and material to be rolled O Neutral line

Claims (3)

It is a method of manufacturing a hat-shaped steel sheet pile by subjecting the material to be rolled to rough rolling, intermediate rolling and finish rolling.
The rolling of the material to be rolled in the rough rolling step, the intermediate rolling step and the finish rolling step is performed by multi-pass rolling in a plurality of hole molds.
In the rolling with the plurality of hole types, in at least two hole types, the front hole type has a flange thickness from the vicinity of the rolling neutral line of the flange corresponding portion to the vicinity of the web shoulder, and from the vicinity of the rolling neutral line to the vicinity of the arm base. Is thicker than the vicinity of the rolling neutral line , the thickening of the flange near the web shoulder in the front hole type is added by projecting to the outside of the facing flange, and the thickening of the flange near the arm base in the front hole type is opposed. Overhang and add to the inside of the flange
The latter-stage hole type is a method for manufacturing a hat-shaped steel sheet pile, characterized in that the flange-corresponding portion having a thick flange is rolled so as to be strongly compressed. The flange reduction rate (%) in the vicinity of the web shoulder and the vicinity of the base of the arm in the latter-stage hole type is set to a strong reduction rate of 2% or more and 8% or less as compared with the vicinity of the rolling neutral line. Here, the flange reduction rate (%) is used. The method for manufacturing a hat-shaped steel sheet pile according to claim 1, wherein the percentage is obtained by dividing the difference between the flange thickness before rolling and the flange thickness after rolling in the rolling by the flange thickness before rolling. A manufacturing facility for manufacturing hat-shaped steel sheet piles, including rough rolling mills, intermediate rolling mills and finish rolling mills.
Each rolling mill has a hole mold, and the rough rolling mill, the intermediate rolling mill, and the finish rolling mill are arranged so that the material to be rolled is sequentially rolled by the hole mold.
In at least two hole types, in the front hole type, the flange thickness from the vicinity of the rolling neutral line to the vicinity of the web shoulder of the flange corresponding portion and from the vicinity of the rolling neutral line to the vicinity of the arm base is thicker than that in the vicinity of the rolling neutral line. , The thickening of the flange near the web shoulder in the front hole type is added by projecting to the outside of the facing flange, and the thickening of the flange near the arm base in the front hole type is added by projecting to the inside of the facing flange. Is configured to
The latter-stage hole type is a hat-shaped steel sheet pile manufacturing facility characterized in that the flange-corresponding portion having a thicker flange is configured to be strongly pressed down from the vicinity of the rolling neutral line.

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