Manufacturing method of steel sheet pile

Abstract

To provide a steel sheet pile manufacturing method which can efficiently roll a steel sheet pile by effectively utilizing an edger rolling machine in one rolling line without performance of shifting of a rolled material between grooves of an intermediate rolling machine by use of H-shaped steel rolling equipment.SOLUTION: According to a manufacturing method for a steel sheet pile having a flange part, a web part and a joint part, in a rolling line comprising an edger mill that are located proximately with a universal mill in series and along the universal mill and a rolling direction, thickness reduction of the entire cross section of a rolled material is performed by the universal mill, and reduction and formation of a joint corresponding part of the rolled material are performed by the edger mill.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a manufacturing method for a steel sheet pile, in which a joint of a steel sheet pile is formed by utilizing an edger mill in a shaped steel factory having a universal mill and an edger mill. [Background technology]

[0002] For example, in the civil engineering and construction fields, the joints (claws) of steel sheet piles used to form earth retaining and revetment structures are generally formed at the same time as the thickness reduction of the steel sheet pile body (e.g. flanges, webs, etc.) using a groove. A steel mill capable of producing H-beams and steel sheet piles is mainly composed of a roughing mill (BD mill), intermediate rolling mills (universal mill, edger mill) and finishing rolling mills. During the production of steel sheet piles, the rough shaped material discharged from the heating furnace is rolled into steel sheet piles by a rolling mill row consisting of these rolling mills. However, the above-mentioned edger mill (compact 2Hi rolling mill) is a rolling mill used to form the flange width when rolling H-beams, and is not used in principle in the production of steel sheet piles.

[0003] Conventionally, the forming of the joint of the steel sheet pile is generally performed when the entire material to be rolled (steel sheet pile) is rolled. In the intermediate rolling mill, a first groove (see FIG. 2(a)) for extending the entire cross section of the material to be rolled and a second groove (see FIG. 2(b)) for adjusting the joint height of the material to be rolled are arranged in parallel. After the material to be rolled is rolled by the first groove, the material to be rolled is shifted and the entire material is rolled by the second groove, including highly accurate dimensional adjustment of the joint. In addition, the first groove and the second groove are arranged in parallel in the intermediate rolling mill because a large-scale mill capable of applying a very large rolling load (rolling torque) is required to roll the entire material to be rolled, and it is extremely difficult to arrange multiple such large-scale mills in series from the viewpoint of concerns about the expansion of the rolling line and rolling equipment and the rise in costs.

[0004] However, when the material to be rolled is shifted in the width direction between the first and second grooves, it is difficult to shift the steel material uniformly over its entire length as a result of the already occurring rolling elongation, and problems such as left and right misalignment are likely to occur in the rolling of the next pass. In particular, the cropped portion is prone to deformation imbalance between the left and right, so it is often not accurately engaged with the grooves. In addition, there is a problem that the shift causes pitch loss, resulting in a drop in rolling temperature and a decrease in productivity.

[0005] Therefore, for example, Patent Document 1 discloses a manufacturing method for a straight steel sheet pile in which reciprocating rolling (hereinafter also referred to as multi-pass rolling) is performed on the same pass line without shifting using a roughing universal rolling mill and an edger rolling mill. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-170703 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the manufacturing method described in the above Patent Document 1, although the manufacturing of a straight steel sheet pile is disclosed, the manufacturing of steel sheet piles of other shapes, such as U-shaped steel sheet piles and hat-shaped steel sheet piles, is not described. This is because the rolling load of an edger rolling mill is generally only half or less than that of an intermediate rolling mill (for example, the rolling load of an intermediate rolling mill is 1000t or more, and the rolling load of an edger rolling mill is less than 400t), and therefore there is a problem that the rolling load of the edger rolling mill is not sufficient to roll the entire U-shaped steel sheet pile or hat-shaped steel sheet pile in one rolling line including the edger rolling mill.

[0008] In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a steel sheet pile, which enables efficient rolling of the steel sheet pile by effectively utilizing an edger rolling mill in one rolling line without shifting the rolled material between the grooves of an intermediate rolling mill using H-shaped steel rolling equipment. [Means for solving the problem]

[0009] In order to achieve the above object, according to the present invention, there is provided a method for manufacturing a steel sheet pile having a flange portion, a web portion, and a joint portion, comprising: a rolling line including a universal mill and an edge mill arranged in series adjacent to the universal mill along a rolling direction, the universal mill reduces the entire cross-sectional thickness of the rolled material, and the edge mill reduces and forms the joint-corresponding portion of the rolled material, In the rolling and forming of the joint corresponding portion in the edge mill, in the web corresponding portion of the rolled material, a gap is provided between the roll and the rolled material except for the connection portion with the flange corresponding portion of the rolled material, in the flange corresponding portion of the rolled material, the rolled material is restrained including the connection portion with the web corresponding portion and the connection portion with the arm corresponding portion of the rolled material, and in the arm corresponding portion of the rolled material, a gap is provided between the roll and the rolled material except for the connection portion with the flange corresponding portion and the connection portion with the joint corresponding portion. A method for manufacturing a steel sheet pile is provided.

[0013] In addition, in the above-mentioned steel sheet pile manufacturing method, the reduction of the entire cross-sectional thickness of the rolled material and the reduction and shaping of the joint corresponding portion of the rolled material are performed by multi-pass rolling in which the universal mill and the edge mill are continuously moved back and forth multiple times, and the reduction and shaping of the joint corresponding portion of the rolled material by the edge mill may be performed only at the end of the multi-pass rolling. Effect of the Invention

[0014] According to the present invention, a method for manufacturing steel sheet piles is provided, which makes it possible to efficiently roll steel sheet piles by effectively utilizing an edge rolling mill in a single rolling line without shifting the rolled material between the grooves of an intermediate rolling mill using H-shaped steel rolling equipment. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic explanatory diagram of a rolling facility. [Diagram 2] 1 is a schematic diagram showing the groove cross-sectional shape of a universal mill (a) and the groove cross-sectional shape of an edge mill (b) that constitute a second intermediate rolling mill. [Diagram 3] FIG. 2 is a schematic overall cross-sectional view showing a state in which a material to be rolled is restrained in an edger mill. [Figure 4] FIG. 4 is a schematic diagram of a web-compatible portion. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 13 is an explanatory diagram showing the rolling load performance of a conventional groove of a completely non-constrained type. [Figure 8] FIG. 11 is an explanatory diagram regarding the rolling load performance by the groove having the configuration according to the present embodiment. [Figure 9] 1 is a graph showing the measurement results of an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, components having substantially the same functional configurations are denoted by the same reference numerals, and duplicated description will be omitted. In the following embodiment, for example, a case in which a hat-shaped steel sheet pile is manufactured by the manufacturing method of a steel sheet pile according to the present invention will be described as an example. In this embodiment, a slab or the like is rolled into a rough material, a first intermediate material, and a second intermediate material according to the rolling process of the steel sheet pile, and these are also collectively referred to as a rolled material A.

[0017] (Rolling equipment configuration) FIG. 1 is a schematic explanatory diagram of a rolling facility 1 for carrying out a manufacturing method of a steel sheet pile according to an embodiment of the present invention. As shown in FIG. 1, the rolling facility 1 is configured by arranging a roughing mill (BD mill) 10, a first intermediate rolling mill 20, a second intermediate rolling mill 30, and a finishing rolling mill 40 in order from the upstream along a rolling line L. The second intermediate rolling mill 30 is composed of a universal mill 32 and an edger mill 34 arranged in series and adjacent to each other. In addition, this rolling facility 1 has the same configuration as the facility generally used when rolling H-shaped steel, and it is possible to divert the rolling facility of H-shaped steel in a normal rolling factory to the manufacturing of steel sheet piles.

[0018] In the rolling facility 1 shown in FIG. 1, a material to be rolled, such as a slab, discharged from a heating furnace (not shown) is first subjected to multi-pass rolling (rolling in which the material to be rolled is rolled back and forth multiple times in a rolling mill) in a roughing mill 10 to form a rough material. Then, the rough material is rolled into a first intermediate material in a first intermediate rolling mill 20. Next, the first intermediate material is rolled into a second intermediate material in a second intermediate rolling mill 30. Here, the rolling in the first intermediate rolling mill 20 and the second intermediate rolling mill 30 is also performed by multi-pass rolling. After that, the second intermediate material is formed into a final product shape in a finishing rolling mill 40 to manufacture a steel sheet pile.

[0019] (Intermediate rolling mill groove configuration) The configuration of the second intermediate rolling mill 30 and the rolling of the first intermediate material to the second intermediate material in the second intermediate rolling mill 30 will be described in detail below. Fig. 2 is a schematic diagram of the groove cross-sectional shape (a) of the universal mill 32 constituting the second intermediate rolling mill 30 and the groove cross-sectional shape (b) of the edge mill 34. Here, in Fig. 2 and its description, the material A to be rolled is composed of a web corresponding part 3 corresponding to the web of the hat-shaped steel sheet pile product, flange corresponding parts 4 and 5 connected to both ends of the web corresponding part 3, arm corresponding parts 6 and 7 formed at the respective tips of the flange corresponding parts 4 and 5, and joint corresponding parts 8 and 9 formed at the tips of the arm corresponding parts 6 and 7, and the material A to be rolled is illustrated by a dashed line in the figure.

[0020] As shown in Fig. 2(a), the groove provided in the universal mill 32 is composed of an upper grooved roll 60 as a protruding roll and a lower grooved roll 61 as a grooved roll. In this groove, the material A to be rolled is reduced, and the joint shape is roughly formed. The entire material A to be rolled is reduced so that the cross-sectional shape becomes a substantially hat-shaped cross-sectional shape forming the joint portion.

[0021] 2(b), the groove provided in the edger mill 34 is composed of an upper grooved roll 70 as a protruding roll and a lower grooved roll 71 as a groove roll. In this groove, rolling is performed to determine the shape of the joint corresponding parts 8, 9 (joint shape) and the joint thickness, and this determines the final product shape including the joint shape.

[0022] As shown in Fig. 2, the groove cross-sectional shape of the universal mill 32 and the groove cross-sectional shape of the edge mill 34 are almost the same shape except for the shape of the joint portion. In the groove cross-sectional shape of the universal mill 32, the groove of the part corresponding to the joint has an open shape (free spreading shape) at the tip, and the material to be rolled (first intermediate material) is subjected to full cross-sectional thickness reduction in the universal mill 32. In addition, in the groove cross-sectional shape of the edge mill 34, the groove of the part corresponding to the joint has a shape in which the tip is constrained, and the joint corresponding portions 8, 9 of the material to be rolled (first intermediate material) are reduced and formed.

[0023] The rolling of the first intermediate material in the second intermediate rolling mill 30 is performed by multi-pass rolling, in which the first intermediate material is rolled by continuously moving back and forth multiple times so as to pass through both the universal mill 32 and the edge mill 34. In this multi-pass rolling, the reduction and shaping of the joint corresponding portions 8, 9 of the rolled material (first intermediate material) by the edge mill 34 is performed only in the latter passes or only at the final time.

[0024] (Constraint of the material being rolled in the edger mill) As described above, in the manufacturing method of the steel sheet pile according to the present embodiment, in the multi-pass rolling of the rolled material (first intermediate material), only the reduction and shaping of the joint corresponding parts 8, 9 are performed in the edge mill 34 at the end of the multi-pass rolling. Here, in the edge mill 34, only the joint corresponding parts 8, 9 are reduced and shaped, and the main body part (for example, the web corresponding part 3 and the flange corresponding parts 4, 5) of the rolled material A (first intermediate material) is not reduced in principle. Therefore, if the entire cross section of the joint corresponding parts 8, 9 is reduced, a shape defect called so-called bite-out occurs at the tip part. That is, in the reduction and shaping of the joint corresponding parts 8, 9 of the rolled material in the edge mill 34, it is necessary to perform the reduction and shaping in a state where the suitable parts of the joint corresponding parts 8, 9 are restrained. Therefore, as a result of intensive research, the inventors discovered that the above problem can be solved by adopting a groove design that optimizes the restraint state of the rolled material A when rolling and forming the joint corresponding portions 8, 9 of the rolled material A in the edge mill 34.

[0025] Here, the restraint state of the rolled material A in the edge mill 34 according to this embodiment will be described with reference to the drawings. FIG. 3 is a schematic overall cross-sectional view of the groove showing the restraint state of the rolled material A in the edge mill 34. Also, FIGS. 4 to 6 are explanatory views showing the restraint state of the rolled material A in the edge mill 34, and are schematic enlarged views of parts A to C shown by dashed lines in FIG. 3, FIG. 4 is a schematic view of the web corresponding part 3, and FIGS. 5 and 6 are schematic views of the left and right joint corresponding parts 8 and 9, respectively. In addition, in FIGS. 3 to 6, the rolled material A and the groove shape are illustrated superimposed, with the solid line indicating the groove and the dashed line indicating the rolled material A.

[0026] As shown in Fig. 3, the material A to be rolled in the edger mill 34 is reduced and formed in a partially unconstrained state. Specifically, the web corresponding portion 3 and the left and right joint corresponding portions 8 and 9 are unconstrained except for some portions. On the other hand, the flange corresponding portions 4 and 5 are in contact with the rolls on both the upper and lower surfaces and are in a constrained state except for the corner portions described later.

[0027] 4, for example, in the web corresponding portion 3, reduction and forming are performed with a gap (relief) provided between the roll and the rolled material A, except for corner portions (R portions) 80, 81 which are connection portions with the left and right flange corresponding portions 4, 5. This gap related to the web corresponding portion 3 may be formed mainly between the rolled material A and the upper perforated roll 70, for example, as shown in the figure.

[0028] As shown in Figs. 4 to 6, the roll gap is set at the flange corresponding parts 4, 5 to be equal to the thickness of the flange corresponding parts 4, 5 finished by the front stage groove. In other words, the thickness of the flange corresponding parts 4, 5 is not actively reduced, and the steel material (rolled material A) being rolled is restrained so that it does not slip. However, during operation, the thickness of the steel material may vary, so it is desirable to set the conditions for light reduction, and it has been confirmed by tests that it is possible to restrain the steel material by setting such conditions. In other words, the flange corresponding parts 4, 5 are reduced and formed in a state where the corner parts 80, 81, the corner parts (R parts) 85, 86 which are the connection parts with the arm corresponding parts 6, 7, and the flange corresponding parts 4, 5 are all restrained.

[0029] 5 and 6, in the arm corresponding parts 6, 7, reduction and forming are performed with a gap (relief) provided between the roll and the rolled material A, except for corner parts 85, 86 and corner parts (R parts) 90, 91 which are connection parts with the joint corresponding parts 8, 9. The gaps related to these arm corresponding parts 6, 7 may be formed, for example, such that one (arm corresponding part 6) is mainly formed between the rolled material A and the upper groove type roll 70, and the other (arm corresponding part 7) is mainly formed between the rolled material A and the lower groove type roll 71, as shown in the figures.

[0030] In this way, in the edge mill 34, the rolled material A is restrained only at each connection portion (corner portion) with respect to the web corresponding portion 3, the flange corresponding portions 4 and 5, and the arm corresponding portions 6 and 7, and the other portions are left unrestrained with gaps provided, and as a general rule, no reduction is performed.

[0031] On the other hand, as shown in Figures 5 and 6, in the joint corresponding parts 8, 9, the tip parts 8a, 9a and the web side end parts 8b, 9b are in a constrained state, and only the joint bottom parts 8c, 9c are unconstrained. In the examples described later, the shapes of the joint corresponding parts 8, 9 rolled and formed in a state where the joint bottom parts 8c, 9c are constrained are compared with the shapes of the joint corresponding parts 8, 9 rolled and formed in a state where the joint bottom parts 8c, 9c are unconstrained, to clarify the above findings.

[0032] (Action and effect) In the edge mill 34, the main body portion of the material A to be rolled (for example, the web corresponding portion 3) is not reduced, and in principle is not restrained. However, if it is completely unrestrained, problems such as the material A to be rolled being displaced relative to the groove will occur. Therefore, as described in this embodiment, in the reduction and forming of the joint corresponding portions 8, 9 of the material A to be rolled in the edge mill 34, it was confirmed through verification that the above problem can be solved by applying light reduction conditions to the flange corresponding portions 4, 5 and reducing and forming while restraining various connecting portions such as the connecting portions with the web corresponding portion 3 (the above corner portions 80, 81).

[0033] Fig. 7 is an explanatory diagram of the rolling load performance of a conventional groove of a completely non-constrained type, and Fig. 8 is an explanatory diagram of the rolling load performance of a groove having a configuration according to this embodiment (hereinafter, referred to as the new groove). In Fig. 7 and Fig. 8, (a) shows the groove shape and the position of the gap (relief) provided therein, and (b) shows a graph of the rolling load performance in the longitudinal direction. In Fig. 7(a) and Fig. 8(a), the places marked with thick lines along the groove shape are the places where the relief is provided.

[0034] As shown in Figure 7(b), in the conventional groove, the rolling load increases at the biting end (dotted line in the figure), and the rolling load increases as a result of the rolled material A being bitten at the biting end shifting left and right. In the conventional groove shown in Figure 7(a), gaps (relief) are provided in the groove in all parts of the arm corresponding part, flange corresponding part, and web corresponding part in order to reduce the rolling load due to thickness reduction. Therefore, the rolling material A is likely to be bitten at the biting end shifting left and right, and an increase in the rolling load at the biting end was observed as shown in Figure 7(b).

[0035] On the other hand, as shown in Fig. 8(b), in the new groove, there is no gap (relief) in the flange corresponding portion, so that the misalignment is unlikely to occur. Therefore, there is no increase in the rolling load at the bite end (dotted line in the figure). This is because, in the conventional groove, the arm corresponding portion and the web corresponding portion, which are thicker than the flange corresponding portion, are misaligned and bitten by the roll facing the flange corresponding portion, resulting in an increase in the rolling load, whereas in the new groove, there is no gap (relief) in the flange corresponding portion, so that the arm corresponding portion and the web corresponding portion are unlikely to be misaligned by the roll facing the flange corresponding portion, and the increase in the rolling load due to the misalignment is suppressed.

[0036] In the case of using rolling equipment for H-beams, conventionally, the steel sheet pile is manufactured, particularly the joint corresponding parts 8, 9 are rolled and formed by performing multi-pass rolling in two parallel grooves in the second intermediate rolling mill 30. However, by applying the manufacturing method of the steel sheet pile according to the embodiment of the present invention, the universal mill 32 and the edge mill 34 arranged in series are used, and the rolling of the main body part of the rolled material (for example, the web corresponding part 3 and the flange corresponding parts 4, 5) is mainly performed by the universal mill 32, and the rolling and forming of the joint corresponding parts 8, 9 is performed by the edge mill 34. This reduces the load on the rolls in the universal mill 32 and the edge mill 34, and makes it possible to efficiently roll the rolled material and roll and form the joint corresponding parts 8, 9, such as improving the elongation length. That is, the load on the edge mill 34 is suppressed, and the rolling and forming of the joint corresponding parts 8, 9 can be effectively performed even with an edge mill with a small rolling load.

[0037] In addition, in the past, in the second intermediate rolling mill 30, rolling was performed using two grooves arranged in parallel on one caliber, which resulted in significant roll deflection and caused bending of the rolled material A. However, in the manufacturing method of the steel sheet pile according to the present embodiment, rolling is performed using one groove each in the universal mill 32 and edge mill 34, which are separate rolling mills, so that it is possible to keep the roll deflection low, suppress the occurrence of bending of the rolled material A, and improve the yield.

[0038] Furthermore, conventionally, in the second intermediate rolling mill 30, rolling was performed by shifting (moving in the width direction of the material to be rolled) the material to be rolled A between two grooves arranged in parallel. However, in the manufacturing method of the steel sheet pile according to the present embodiment, multi-pass rolling is performed by only moving the material to be rolled A in the longitudinal direction between the universal mill 32 and the edge mill 34 arranged in series, which makes it possible to eliminate the time required for shifting the material to be rolled A and to prevent the occurrence of defective shapes and defective ends (defective parts called so-called crops) due to the material to be rolled A not being accurately engaged in the grooves after shifting.

[0039] Although an example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can conceive of various modified or altered examples within the scope of the idea described in the claims, and it is understood that these naturally fall within the technical scope of the present invention. For example, in the above embodiment, the manufacturing method of the steel sheet pile according to the present invention has been described by taking the hat-shaped steel sheet pile as an example, but the scope of application of the present invention is not limited to this, and the present invention can be applied to any steel sheet pile having a flange portion, a web portion, and a joint portion, and can also be applied to a Z-shaped steel sheet pile with a completely asymmetric cross section, a U-shaped steel sheet pile with a left-right asymmetric cross section, etc. EXAMPLES

[0040] (Example) As an example of the present invention, the maximum value (MAX value) and average value (MID value) of the rolling load (rolling reaction force) were measured when the joint bottom and various corners were rolled and formed in an unconstrained state using an edge mill as described in the above embodiment. Figure 9 is a graph showing the measurement results.

[0041] As shown in Fig. 9, the rolling load of the edger mill when the present invention is applied is about 100t for both the rolling load at the time of biting and the rolling load in the steady state. In contrast, for example, the equipment specifications for edger mills in general shaped steel equipment state that the rolling load is up to 400t (i.e., the load capacity of the rolling mill = 400t), but the results of this embodiment are significantly lower than this, and it is understood that the load on the edger mill is suppressed.

[0042] On the other hand, if the present invention is not applied and the full cross-section thickness reduction of the rolled material is performed using an edge mill, it is technically common knowledge that the rolling load increases significantly, and it is known that a rolling load of about 1000t will be generated. In other words, if the full cross-section thickness reduction is performed, it will exceed the maximum rolling load (load capacity) of the edge mill equipment of 400t, and it is clear that this is not feasible. [Industrial Applicability]

[0043] INDUSTRIAL APPLICABILITY The present invention can be applied to a manufacturing method for a steel sheet pile in which a joint of a steel sheet pile is formed by utilizing an edger mill in a shaped steel factory having a universal mill and an edger mill. [Explanation of symbols]

[0044] 1...Rolling equipment 3. Web Support Department 4, 5...Flange corresponding part 6, 7…Arm corresponding parts 8, 9...Joint compatible parts 10...Roughing mill 20…First intermediate rolling mill 30…Second intermediate rolling mill 32…Universal mill 34…Edger mill 40...Finishing rolling mill 60...Upper perforated roll (of universal mill) 61...(Universal mill) lower hole roll 70...(Edger mill) upper perforated roll 71...(Edge mill) lower hole roll 80, 81, 85, 86, 90, 91…Corner section L…Rolling line A: Rolled material

Claims

1. A manufacturing method for a steel sheet pile having a flange portion, a web portion, and a joint portion, A rolling line including a universal mill and an edge mill disposed adjacent to the universal mill in series along the rolling direction, The universal mill reduces the thickness of the rolled material in its entire cross section, The edge mill reduces and forms the joint corresponding portion of the rolled material, In the pressing and forming of the joint corresponding portion in the edge mill, In the web-corresponding portion of the rolled material, a gap is provided between the roll and the rolled material except for the connection portion with the flange-corresponding portion of the rolled material, In the flange corresponding portion of the rolled material, the rolled material is restrained including the connection portion with the web corresponding portion and the connection portion with the arm corresponding portion of the rolled material, A manufacturing method for a steel sheet pile, in which a gap is provided between the roll and the rolled material in the arm corresponding portion of the rolled material, except for the connection portion with the flange corresponding portion and the connection portion with the joint corresponding portion.

2. The method for manufacturing a steel sheet pile according to claim 1, wherein the rolling and forming of the joint corresponding portion of the rolled material is performed in a state where a joint bottom portion of the joint corresponding portion is not restrained.

3. The reduction of the entire cross-sectional thickness of the rolled material and the reduction and shaping of the joint corresponding portion of the rolled material are performed by multi-pass rolling in which the universal mill and the edge mill are continuously reciprocated multiple times, The method for manufacturing a steel sheet pile according to claim 1 or 2, wherein the reduction and shaping of the joint corresponding portion of the rolled material by the edge mill is performed only at the final time of the multi-pass rolling.

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