JP7127729B2 - Steel sheet pile manufacturing method and rolling equipment train for steel sheet pile manufacturing - Google Patents

Description

The present invention relates to a method for manufacturing steel sheet piles and rolling equipment trains for manufacturing steel sheet piles, and more particularly to a method for manufacturing tall steel sheet piles and rolling equipment trains for manufacturing steel sheet piles.

Hat-shaped steel sheet piles, U-shaped steel sheet piles, and the like are examples of steel sheet piles that are suitable as earth retaining members for civil engineering work. FIG. 1 shows cross-sectional shapes of a hat-shaped steel sheet pile (FIG. 1(a)) and a U-shaped steel sheet pile (FIG. 1(b)) as examples of product shapes.

The steel sheet pile 1 is normally manufactured using a slab, a bloom, or the like as a raw material, for example, in a rolling facility example 2 for manufacturing steel sheet piles shown in FIG. In such a rolling equipment train 2, the raw material is charged into the heating device 3 and heated to a predetermined temperature, for example, 1300 ° C., and then the heated raw material is transferred to the rough rolling mill 4, the intermediate rolling mill 5 and the finishing rolling mill. 6, and rolled to a predetermined cross-sectional shape to obtain a product shape. The rolling by the rough rolling mill 4 is also called rough rolling, the rolling by the intermediate rolling mill 5 is called intermediate rolling, and the rolling by the finishing rolling mill 6 is also called finish rolling. These rolling mills are equipped with rolling rolls in which calibers called calibers are engraved on upper and lower rolls. In addition, below, an upper roll and a lower roll are collectively called an upper-lower roll or a roll group.

FIG. 3 shows an example of grooves engraved on the upper and lower rolls of the roughing mill 4 used for roughing hat-shaped steel sheet piles. Three calibers, a Box caliber 71, a K8 caliber 72 and a K7 caliber 73, are engraved on the upper roll 41 and the lower roll . In the rough rolling using this caliber, the width of the slab is first reduced by the Box caliber 71 using the slab as the raw material. Next, the K8 hole die 72 bends the slab into a hat shape and reduces the thickness. Further, the K7 hole die 73 performs thickness reduction, and the material is formed into a shape close to the cross-sectional shape of the product. In addition, in the K8 caliber 72 and the K7 caliber 73, multiple passes of rolling are performed.

Like the roughing mill 4, the intermediate rolling mill 5 used for intermediate rolling is also provided with rolling rolls having two to four calibers engraved on the upper and lower rolls. FIG. 4 shows an example of grooves engraved on the upper and lower rolls of the intermediate rolling mill 5 used for intermediate rolling of hat-shaped steel sheet piles. In FIG. 4, two calibers, K3 caliber 75 and K6 caliber 74, are engraved on the upper roll 51 and the lower roll 52 . Although not shown, two calibers, a K4 caliber 77 and a K5 caliber 76, are engraved in the upper and lower rolls of the other intermediate rolling mill 5 in the same manner. In the intermediate rolling, the rough-rolled material is successively rolled with these grooves to reduce the thickness and form the shape, thereby forming the material into a shape closer to the cross-sectional shape of the product.

The finish rolling mill 6 used for finish rolling also has 1 to 3 grooves on the upper and lower rolls. FIG. 5 shows an example of grooves engraved on the upper and lower rolls of the finishing mill 6 used for finish rolling of hat-shaped steel sheet piles. In FIG. 5, two calibers, a K2 caliber 78 and a K1 caliber 79, are engraved on the upper roll 61 and the lower roll 62 . In the finish rolling, the intermediate rolled material is subjected to final thickness reduction with the K2 grooved mold 78, and then the joint portion 14 is bent and formed with the K1 grooved mold 79, thereby shaping the material into the final product cross-sectional shape. shape.
In intermediate rolling and finish rolling, the number of rolling passes in each groove is basically one pass, and the number of rolling passes in the same groove is about two or three passes at most.

Similarly to the hat-shaped steel sheet piles, the U-shaped steel sheet piles are also manufactured by performing caliber rolling by a plurality of rolling mills so as to gradually obtain the cross-sectional shape of the products.
With respect to such steel sheet piles, there has recently been a trend toward increasing the size of steel sheet piles in order to improve rigidity and section modulus, as well as to improve workability.

In response to this trend, for example, Patent Document 1 describes a "roll forming apparatus" for forming light weight steel sheet piles having a large height dimension. The "roll forming apparatus" described in Patent Document 1 is a roll forming roll stand in which a claw forming roll stand, a first half bending roll stand, a second half bending roll stand, and a shaping roll stand are configured in this order. It is a device. The nail forming roll stand consists of a pair of upper and lower horizontal grooved rolls for preforming nails on both ends of a flat material. In addition, the front half bending roll stand is provided on a pair of upper and lower horizontal flat rolls that press down only the web portion of the lightweight steel sheet pile and on roll shafts that are independent of each other, and performs bending of the second bending portion. and a pair of upper and lower horizontal V-bending rolls. In the front half bending roll stand, part of the forming of the first bent portion and most of the forming of the second bent portion are performed. In addition, the latter half bending roll stand includes a pair of upper and lower horizontal flat rolls sandwiching the web portion, an inclined roll provided on an inclined roll shaft and in contact with the outer surface of the flange portion, and the lower surface side of the second bent portion. a receiving roll for receiving; In Patent Document 1, the final forming of the first bent portion is performed in the latter half bending roll stand. Further, in Patent Document 1, the shaping roll stand is similar to the conventional one, and includes a pair of upper and lower caliber rolls for forming a caliber of the final cross-sectional shape, and performs shaping of the product. According to the roll forming apparatus described in Patent Document 1, even when forming a cross-sectional shape with a large height dimension, the roll diameter can be significantly reduced.

Further, Patent Document 2 describes a “method for manufacturing a steel sheet pile”. The technique described in Patent Document 2 manufactures steel sheet piles having different cross-sectional shapes by manufacturing hat-shaped or U-shaped steel sheet piles by hot rolling and then forming the steel sheet piles by cold working. The method. In the technique described in Patent Document 2, cold working is processing to widen or narrow the width direction of the steel sheet pile, or processing to widen or narrow the angle of the steel sheet pile corner portion. is preferred. According to the technique described in Patent Document 2, it is possible to manufacture steel sheet piles that cannot be manufactured with the same hot rolling equipment, and it is possible to manufacture steel sheet piles with a high degree of freedom.

Further, Patent Document 3 describes a "method for manufacturing a channel". The technique described in Patent Document 3 is a "method for manufacturing a channel profile" in which a rough rolling step and a finishing step are performed in order. Here, in the rough rolling step of Patent Document 3, a plurality of sets of double rolling rolls having a predetermined caliber are used to perform groove rolling on a rolling material heated to a predetermined temperature to produce an intermediate product. At this time, the shape of the cross section of the material to be rolled is a convex shape in which the pair of flange portions are inclined outward with respect to the vertical line, and the web portion protrudes toward the flange portions. The intermediate product is formed by connecting both ends of the web portion to the flange portion at a substantially right angle and making the thickness of the flange portion and the web portion substantially the same as the product dimensions. Next, in the rough rolling step, the tip of the flange portion of the intermediate product is formed into a concave shape having a convex portion bulging in the thickness direction in the cross-sectional shape with a four-axis rolling roll, and then the tip portion of the flange portion is rolled. Rolling is performed in the thickness direction to adjust the flatness of the flange portion. In addition, in the finishing process, a plurality of sets of forming rolls arranged in parallel to each other form the convex-shaped web portion of the intermediate product, and the flange portion perpendicular to the web portion and substantially parallel to each other and the flat web A step of forming a channel member having a portion by roll working (cold, warm, hot). According to the technique described in Patent Document 3, it is possible to improve the flatness of the end surface of the tip portion of the flange portion while suppressing the occurrence of surface defects even for a material having low hot deformability.

Further, Patent Document 4 describes a "method for manufacturing channel steel". In the "method for manufacturing channel steel" described in Patent Document 4, channel steel is manufactured by successively rolling with a plurality of pairs of horizontal grooved rolls. At this time, a thickness difference of [web>flange] is given to the web part and the flange part of the material to be rolled before the pass before finishing, and the web and the flange are rolled in a curved shape. Between the pre-finishing pass and the final finishing pass, the opening angle of the flange is reduced by performing hot rough forming without contacting the rolls with the flange portion. Subsequently, in Patent Document 4, after passing through the final finishing pass, the rolled material is straightened by hot straightening. According to the technique described in Patent Document 4, this makes it possible to mass-produce channel steel made of high alloy steel easily and at low cost without causing roll slip flaws.

Further, Patent Document 5 describes a "method for manufacturing a hot-rolled channel". The technique described in Patent Document 5 uses a plurality of sets of rolling rolls having a predetermined caliber to form a curved web portion having a concave surface and a convex surface on the front and back surfaces, and from both left and right ends of the web portion. A hot rolling step of manufacturing a W-shaped work intermediate material having a flange portion extending substantially at a right angle by hot rolling, and bending the manufactured W-shaped work intermediate material into a U-shape by bending. It is a method of manufacturing a hot-rolled channel by performing a forming process for manufacturing a channel. In the technique described in Patent Document 5, the forming process includes the first roll that contacts the concave surface of the web portion of the work intermediate material, and the central protruding portion of the convex surface of the web portion that contacts the central protruding portion. A rough forming step using a second roll having a gap is performed by hot forming in the vicinity of the end near the end. In the rough forming step, it is preferable to press the flange portion inward by a pair of left and right guide rolls provided on the left and right sides of the first roll and the second roll to promote the above-described bending. According to the technique described in Patent Document 5, it is possible to consistently manufacture in the hot state, and it is possible to manufacture a hot-rolled channel of excellent quality.

Japanese Patent Application Laid-Open No. 07-088562 JP-A-2003-230916 Japanese Patent Application Laid-Open No. 04-066202 Japanese Patent Application Laid-Open No. 05-154502 Japanese Patent Application Laid-Open No. 2001-276902

However, the technique described in Patent Literature 1 is limited to the manufacture of lightweight steel sheet piles by cold bending, and requires cold roll forming equipment with a complicated configuration. Moreover, the technique described in Patent Document 2 has a problem that it requires not only hot rolling equipment but also cold working equipment. In addition, the techniques described in Patent Documents 3 to 5 are methods for manufacturing channel steel or channel steel, and in the rolling method for these channel steel (channel steel), the web portion and the flange portion In addition to being unstable in bending, there is a problem in that it is difficult to apply to steel sheet piles that require claw formation at joints in the final stage of hot rolling. Furthermore, recently, there is a demand for a large steel sheet pile having an effective width W of 900 mm and an effective height H of over 300 mm.

In order to roll a steel sheet pile with a high effective height H (hereinafter also referred to as a "high height" steel sheet pile), it is necessary to form (roll) using rolls having deep grooves. However, if a deep groove is formed in the roll, the diameter of the small-diameter portion of the roll becomes too small, and the transverse rupture strength of the roll during rolling decreases. In addition, when rolling steel sheet piles with a high effective height H and a wide effective width W under the same reduction conditions as for conventional steel sheet piles with a narrow effective width, the rolling load and rolling torque increase. In the production of large steel sheet piles, the decrease in transverse rupture strength of the rolls and the increase in rolling load are superimposed, and there is a risk that the rolls will break during rolling, making rolling impossible. In addition, since a deep groove is formed in the roll, the diameter of the small-diameter portion of the roll becomes too small, resulting in a significant decrease in the effective usage allowance (effective usage range) of the roll.

The present invention solves the problems of the prior art as described above, and provides a method for manufacturing a steel sheet pile and a method for manufacturing a steel sheet pile that can manufacture a high steel sheet pile only by a hot rolling process without using cold rolling. The purpose is to provide a rolling equipment train of In addition, the "high" steel sheet pile here means a large steel sheet pile with an effective width W of 900 mm or more and an effective height H of more than 300 mm, preferably 350 mm or more. .

In order to achieve the above-described object, the present inventors diligently studied a method of manufacturing a tall steel sheet pile without using deep-groove rolling rolls. As a result, in the rolling passes where the rolling load tends to increase with respect to the groove depth, for example, in a part of rough rolling and intermediate rolling, it was conceived to roll so that the flange portion is curved or bent outward. did. That is, if rolling is performed so that the flange portion is curved or bent outward after intermediate rolling, the caliber of the rolling rolls can be made shallower than when the flange portion has a linear shape. It has been found that it is possible to prevent a reduction in the transverse rupture strength of the rolling rolls and to increase the usage allowance (effective usage range) of the rolls.

The present invention has been completed based on these findings and further studies. That is, the gist of the present invention is as follows.
[1] A steel sheet pile manufacturing method for manufacturing a steel sheet pile having a flange portion of a predetermined shape by subjecting a heated material to rough rolling, intermediate rolling, and finish rolling in this order using a plurality of calibers, In the intermediate rolling, the groove height is smaller than the product height, and the shape of the flange portion after the intermediate rolling is a first shape that curves or bends outward, and the intermediate rolling is performed. In the subsequent finish rolling, the flange portion of the first shape is bent or bent in a straight shape or curved or bent inward, and the height dimension is the height of the product. A method of manufacturing sheet piles.

[2] The method for manufacturing a steel sheet pile according to [1], wherein the rolling pass in which the bending is performed in the finish rolling is a rolling pass using a web guide on the entry side of the rolling.
[3] The web guide has a web guide upper surface width equal to or narrower than the lower surface width of the web of the raw material after the final rolling pass of the intermediate rolling in a cross section orthogonal to the rolling direction, and the intermediate rolling The method for manufacturing a steel sheet pile according to [2], wherein the angle formed by the upper surface of the web guide and the side surface of the web guide is equal to the angle formed by the joint portion between the web portion and the flange portion of the raw material after the final rolling pass of (2).
[4] The method for manufacturing a steel sheet pile according to any one of [1] to [3], wherein in the finish rolling, claw bending is performed in a rolling pass following the rolling pass in which the bending is performed.
[5] The method for manufacturing a steel sheet pile according to [4], wherein preforming for claw bending is performed on the delivery side of a rolling pass in which the bending is performed in the finish rolling, and then the claw bending is performed thereafter.

[6] A rolling equipment train for steel sheet pile manufacturing comprising a heating device, a roughing mill, an intermediate rolling mill and a finishing rolling mill arranged in this order, wherein the roughing mill, the intermediate rolling mill and the finishing rolling The rolling mill is a rolling mill provided with upper and lower rolls on which grooves are engraved, and at least all or part of the grooves on the downstream side of the intermediate rolling mill have a groove height smaller than the product height. , a caliber engraved so that the flange portion has a first shape that curves or bends outward, and the caliber of a part of the finishing rolling mill makes the flange portion of the first shape a straight shape, or , a rolling train for steel sheet pile production, which is a caliber engraved to bend or form a second shape that curves or bends inward and has a height dimension equal to the height of the product.

According to the present invention, a steel sheet pile having a high effective height and a large effective width can be easily and stably produced only by a hot rolling process without using cold rolling, without accidents such as breakage of rolls. It can be manufactured with high productivity, and has a remarkable industrial effect.

It is explanatory drawing which shows typically an example of the product shape of a steel sheet pile. (a) is an example of a hat-shaped steel sheet pile, and (b) is an example of a U-shaped steel sheet pile. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows an example of the rolling equipment example for steel sheet pile manufacture. It is explanatory drawing which shows an example of the caliber (cross section) for rough rolling used for hat-shaped steel sheet pile manufacture. It is explanatory drawing which shows an example of the caliber (cross section) for intermediate rolling used for hat-shaped steel sheet pile manufacture. It is explanatory drawing which shows an example of the caliber (cross section) for finish rolling used for hat-shaped steel sheet pile manufacture. FIG. 3 is a cross-sectional view showing an example of a rough rolling caliber K7 suitable for manufacturing a hat-shaped steel sheet pile in the present invention. FIG. 4 is a cross-sectional view showing an example of an intermediate rolling caliber K3 suitable for manufacturing a hat-shaped steel sheet pile in the present invention. (a) shows an example in which the flange portion is curved outward, and (b) shows an example in which the flange portion is bent outward. FIG. 3 is a cross-sectional view showing an example of a caliber K2 for finish rolling suitable for manufacturing a hat-shaped steel sheet pile in the present invention. It is explanatory drawing which shows typically an example of the product shape of a steel sheet pile. FIG. 4 is a cross-sectional view schematically showing a state of bending back forming of a flange portion in finish rolling. FIG. 4 is an explanatory diagram schematically showing a web guide; (a) shows the shape of the web guide, and (b) shows the arrangement position of the web guide. It is an explanatory view showing an example of a nail bending roller typically.

In one embodiment of the present invention, for example, a steel sheet pile 1 is manufactured using a rolling equipment train 2 shown in FIG.
In this embodiment, a material (steel material; for example, a rectangular slab) is charged into the heating device 3 and heated to a predetermined temperature, for example, 1300.degree. After that, the heated raw material is conveyed to a rough rolling mill 4, an intermediate rolling mill 5 and a finishing rolling mill 6 in this order and rolled to manufacture, for example, a hat-shaped steel sheet pile 1A having a cross-sectional shape shown in FIG. 1(a). do. In addition, in the rolling equipment train 2, by sequentially rolling a plurality of raw materials, products (hat-shaped steel sheet piles 1A) having the same size can be continuously manufactured.

In rolling (rough rolling) in the roughing mill 4, as shown in FIG. A two-hole type for rough rolling of the heated material. In the K8 grooved mold 72 and the K7 grooved mold 73, multiple passes of rolling are performed. In the rough rolling, a slab is used as a raw material. First, the width of the raw material (slab) is reduced by the Box groove 71, then it is turned 90°, and the K8 groove 72 is used to bend the slab into a hat shape. At the same time, thickness reduction (thickness reduction) is performed. Further, the K7 hole die 73 continuously performs thickness reduction and rough forming of the joint portion to form a shape close to the cross-sectional shape of the product. The height H7 of the K7 hole mold 73 is set larger than the height H8 of the K8 hole mold 72, and in the K7 hole mold 73, the flange portion is also elongated and deformed.

Further, as shown in FIG. 6, the K7 groove 731 can be engraved so that the flange portion is curved outward, and the flange portion can be rolled into the outward curved shape. In addition, you may roll to the shape which bent the flange part outside. However, in the rough rolling stage, in rolling passes other than the rolling pass where the roll strength tends to be a problem due to the groove depth being deep with respect to the rolling load, the flange portion is rolled in a shape that is curved or bent outward. No need.
Next, the raw material (intermediate raw material) shaped by the rough rolling is subjected to rolling (intermediate rolling) using grooves engraved on the upper and lower rolls of the intermediate rolling mill 5 . In addition, in the rolling equipment train 2 shown in FIG. 2, two rolling mills (two roll sets) are arranged as the intermediate rolling mill 5, and tandem rolling is performed with two grooves arranged in the rolling direction. can also In this rolling (intermediate rolling), the thickness of the material is mainly reduced, but stretching deformation of the flange portion can also be applied.

In the present invention, rolling is performed so that the shape after intermediate rolling becomes the first shape in which the flange portion is curved or bent outward. Further, the flange portion having the first shape refers to a flange portion that curves or bends outward after intermediate rolling.
In the rolling pass where the rolling load tends to increase with respect to the depth of the groove, the material is processed using grooves engraved on the upper and lower rolls (roll set) so that the flange part is curved or bent outward. to roll. Such rolling passes in which the rolling load tends to increase with respect to the groove depth include, for example, some rolling passes of rough rolling, all rolling passes of intermediate rolling, some rolling passes on the downstream side, and the like. is mentioned. In the present invention, at least all the rolling passes of the intermediate rolling or part of the rolling passes on the downstream side are flanged to the upper and lower rolls (roll set) so that the flange portion has a shape that curves or bends outward after the intermediate rolling. It is preferred to use a caliber that is cut so that the portions are curved or bent outward. As the caliber to be used, for example, it is preferable to use a caliber engraved so that the flange portion curves outward, as shown in FIG. 6 for rough rolling and FIG. 7A for intermediate rolling. Moreover, it is also possible to use a caliber formed so that the flange portion is curved outward as shown in FIG. 7(b). As a result, the groove height H (H3 in FIG. 7) can be made smaller than when the flange portion has a linear shape, and the effective usage margin (effective usage range) of the roll is increased.

The intermediate rolling mill 5, as a second intermediate rolling mill, has two holes, a K3 caliber 751 (see FIG. 7) and a K6 caliber 741 (not shown), for the upper roll 51 and the lower roll 52, for example. Two grooves, K5 caliber 761 and K4 caliber 771, are engraved on the rolling rolls engraved with dies and, for example, the upper and lower rolls as a first intermediate rolling mill (not shown). and a rolling roll. Rolling including tandem rolling is sequentially performed as intermediate rolling on the roughly rolled material using these calibers engraved so that the flange portion is curved or bent outward after intermediate rolling. be able to.

In addition, if the height H of the groove used in the intermediate rolling is set to H6 for the K6 groove, H5 for the K5 groove, H4 for the K4 groove, and H3 for the K3 groove, in the order of the rolling passes, the following (1 ), it is preferable to set the height of the groove so as to satisfy the formula.
H6≦H5≦H4≦H3 (1)
By setting the height of the caliber used for intermediate rolling so as to satisfy the formula (1), it is possible to sequentially apply stretching deformation to the flange portion in each caliber, making it a stable high-height steel sheet pile material. The effect of being able to roll effectively can be expected.

Next, the intermediate material shaped by the intermediate rolling is further subjected to rolling (finish rolling) using grooves engraved on the upper and lower rolls of the finishing rolling mill 6 .
In the finishing mill 6, the upper roll 61 and the lower roll 62 are provided with two grooves, for example, a K2 groove 78 (see FIG. 8) and a K1 groove 79 (not shown). Prepare. In the finish rolling of the present embodiment, in the first rolling pass, the K2 groove 78 is used to bend and return the flange portion to form the flange portion into a linear shape. The K2 caliber 78 is a caliber engraved on the upper and lower rolls so that the flange portion exhibits a linear shape. In addition, in the K2 groove, the width of the lower surface of the web of the K2 groove (B2 in FIG. 8) is equal to the width of the lower surface of the web before the K2 groove rolling (B3 in FIG. 7). It is preferable to make the angle (θ2 in FIG. 8) equal to the angle (θ3 in FIG. 7) between the web and the flange before K2 groove rolling. As a result, when the flange portion is bent back and formed, the raw material does not shift in the vertical and horizontal directions, and the flange portion can be bent back and formed stably.

In the above description, the final product shape has a linear flange portion, but the product shape may have a flange portion other than a linear shape. For example, like the cross-sectional shape schematically shown in FIG. 9, the final product shape may be formed by molding into a shape in which the flange portion is curved or bent inward. In this case, the K2 caliber 78 is a caliber formed by engraving the upper and lower rolls so that the flange portion curves or bends inward.
Further, the shape of the flange formed by bending in the finish rolling, that is, the shape in which the flange portion is linear or curved or bent inward is defined as the second shape.

FIG. 10 shows an outline of bending back forming of the flange portion with the K2 hole die 78 . FIG. 10(a) is a cross-sectional view schematically showing the state when the material (intermediate material) after the final rolling pass of the intermediate rolling starts contacting the K2 caliber (at the time of biting). FIG. 10(b) is a cross-sectional view showing a state (at the time of completion of bending) after forming with the K2 hole mold. In this bending back forming, the web portion 11, the flange portion 12, and the arm portion 13 of the material (intermediate material) come into contact with the roll (groove shape) and undergo bending back forming, but the joint portion 14 is bent back from the roll (groove shape). It is preferable to carve a groove so that it does not come into contact with and deform. A K1 hole die 79 is used to bend the claw portion of the joint portion. The number of rolling passes in the K2 groove 78 and the K1 groove 79 is basically one pass.
In the first rolling pass of the finish rolling, as described above, the flange portion is bent back and formed. It is more preferable to roll using the web guide 60 at the entry side of the rolling so that the flange portion can be stably bent back without fluctuation in the stationary length.

The web guide 60 used has a shape in which the width B of the upper surface 601 of the web guide is matched with the width B3 of the lower surface of the web after intermediate rolling, and is equal to the width B3 of the lower surface of the web or slightly narrower than the width B3 of the lower surface of the web. The angle θ between the upper surface 601 and the web guide side surface 602 is preferably equal to θ3 (the angle formed by the joint between the web portion 11 and the flange portion 12) of the caliber K3 at the end of the intermediate rolling. In a web guide in which the width B of the top surface 601 of the web guide is equal to the width B3 of the bottom surface of the web, scratches may occur on the inner surface of the flange or the bottom surface of the web. is preferred. A preferred shape for the web guide is shown in FIG. 11(a). In addition, FIG. 11(b) shows the arrangement position of the web guide 60. As shown in FIG.

By using the web guide 60 as described above on the rolling entry side of the first rolling pass of the finish rolling, the lower surface of the web formed by the intermediate rolling and the joint between the web and the flange are sufficiently held. and can be guided to the K2 hole mold 78 . As a result, it is possible to prevent the raw material from being displaced in the vertical direction and the horizontal direction, and to stably perform the bending back forming of the flange portion.

The bending of the claw portion of the joint portion 14 is performed by the K1 hole mold 79 which is the final hole mold. However, with this single caliber, the amount of claw bending becomes excessive, and there are cases where proper claw bending cannot be performed. In such a case, it is preferable to carry out claw bending preforming of the joint portion. Claw bending preforming of the joint portion is preferably performed by installing a claw bending roller as described in Japanese Patent Laid-Open No. 2006-272343, for example, on the output side (rear surface) of the K2 slot 78 .
Preforming for bending the claw from the outside to the inside is performed by the claw bending roller 8 as shown in FIG. The claw 7A is bent from the outside to the inside by a vertical roller 81 while the top and bottom are restrained. The vertical roller 81 is arranged so that its center axis is positioned outside the claw 7A.

By using such a claw bending roller to perform claw bending preforming of the joint portion and then performing claw bending forming with the K1 hole mold, the amount of claw bending with the K1 hole mold can be optimized.
In the above-described embodiment, the flange portion is bent back and formed in the first rolling pass of the finish rolling. In that case, in addition to the K2 hole mold 78, the K1 hole mold 79 may be used to perform the bending back forming of the flange, or another hole mold may be provided between the K2 hole mold 78 and the K1 hole mold 79. Bending back forming may be performed.

The present invention will be further described below based on examples.

Using the rolling equipment train 2 shown in FIG. , Rolled by a finishing rolling mill 6, web thickness: 17 mm, flange thickness: 12 mm, effective height H: 370 mm, effective width W: 900 mm. A hat-shaped steel sheet pile was manufactured.
In rough rolling, the heated raw material (steel material) is rolled by a rough rolling mill 4 equipped with upper and lower rolls engraved with Box grooves, K8 grooves, and K7 grooves, and shaped into a shape close to the cross-sectional shape of the product. did. Next, the first intermediate rolling mill 5 equipped with upper and lower rolls engraved with K5 and K4 grooves on the raw material shaped by rough rolling, and the upper and lower rolls with K6 and K3 grooves. Rolling (intermediate rolling) was successively performed using a second intermediate rolling mill 5 equipped with rolls. Specifically, in the first rolling pass in the intermediate rolling, the groove K5 and the groove K6 are rolled in this order (K5 does not roll down), and in the second rolling pass, the groove K6 and the groove K5 are rolled in this order, As the third rolling pass, rolling was performed in the order of caliber K4 and caliber K3.

After the intermediate rolling is completed, the flange portion is curved or bent outward to form the first shape. A shallow pore shape was used. The K6 caliber, K5 caliber and K4 caliber also had similar calibers with a shallow caliber depth. Furthermore, in the intermediate rolling, the groove depth H of the used groove is set in the order of the passed groove (K6 groove, K5 groove, K4 groove and K3 groove) in the order of the following (1) formula The pore shape was changed to satisfy
H6≦H5≦H4≦H3 (1)
The depth H of the groove used is shown in Table 1 as a ratio to the product height (standard: 1.0). Steel sheet pile No. 3 is a comparative example in which grooves in which the flange portion exhibits a straight shape are used in all intermediate rolling passes.

For each of the rolling rolls engraved with the caliber of depth H described above, the finite element method is used in advance to calculate the stress generated in each part of the rolling roll during rolling, and this stress is the material of the roll. The rolling withstand load (unit: MN) was calculated for each groove so as not to exceed the allowable stress of . The obtained results are also shown in Table 1. Naturally, when the groove depth H increases, the load capacity decreases and the risk of roll breakage increases.
Next, the material shaped by intermediate rolling was subjected to finish rolling and shaped into a product shape. In the first rolling pass of the finish rolling, the K2 groove 78 was used to bend back the flange portion from the shape in which the flange portion was bent outward to the second shape in which the flange portion exhibits a straight shape.

In part of the first rolling pass of the finish rolling, rolling was performed using the web guide 60 on the entry side of the rolling. The web guide 60 has the shape shown in FIG. The angle θ formed with the side surface of the web guide was made equal to the angle θ3 formed between the web portion and the flange portion at the end of the intermediate rolling.
After performing the first rolling pass of finish rolling, the joint portion was subjected to claw bending using a K2 groove 79 to obtain a hat-shaped steel sheet pile (product). In all of the present invention examples, on the delivery side of the first rolling pass, preforming for claw bending was performed using a claw bending roller, and then claw bending was performed.

For the obtained product (steel sheet pile), the effective width dimension W and height dimension H (see Fig. 1 (a)) are measured from the tip of the rolling, and the joint shape is visually confirmed. The unsteady lengths (longitudinal length (m)) of the leading edge and trailing edge of the rolling where the dimensions W and H and the joint shape did not fall within the tolerance range were measured.
The obtained results are also shown in Table 1.

Under both conditions of steel sheet piles No. 1 and No. 2, which are examples of the present invention, rolling up to the final pass of finish rolling was performed, and products were successfully obtained. In particular, in steel sheet pile No. 2, good results were obtained with little occurrence of unsteady parts at the front and rear ends of the sheet pile, which do not become products due to the effect of the web guide.
On the other hand, in steel sheet pile No. 3, which is a comparative example, the actual rolling load was 12.54 MN in rolling with a K5 groove, which exceeded the load capacity of the rolls of 12.45 MN. Rolling after the K4 caliber was abandoned.
As described above, according to the present invention, it is possible to stably perform the bending back forming of the flange portion and the subsequent claw bending forming, and easily manufacture a tall steel sheet pile. Further, according to the present invention, the depth of grooves formed on the rolling rolls can be made shallower, and the reduction in transverse rupture strength of the rolls can be reduced.

1 Steel sheet pile 1A Hat-shaped steel sheet pile, 1B U-shaped steel sheet pile 2 Rolling equipment row (rolling equipment row for manufacturing steel sheet piles)
3 Heating device 4 Rough rolling mill 5 Intermediate rolling mill 6 Finishing rolling mill 8 Claw bending roller 11 Web part 12 Flange part 13 Arm part 14 Joint part 41 Upper roll (upper rough roll) 42 Lower roll (lower rough roll )
51 upper roll (upper intermediate roll), 52 lower roll (lower intermediate roll)
60 web guide 61 upper roll (finishing roll), 62 lower roll (lower finishing roll)
81 vertical roller, 82 vertical roller, 83 horizontal roller 601 web guide top surface, 602 web guide side surface

Claims (6)

A steel sheet pile manufacturing method for manufacturing a steel sheet pile having a flange portion of a predetermined shape by subjecting a heated material to rough rolling, intermediate rolling, and finish rolling in this order using a plurality of calibers,
In the intermediate rolling, rolling is performed so that the height of the groove is smaller than the height of the product, and the shape of the flange portion after the intermediate rolling is a first shape that curves or bends outward,
In the finish rolling following the intermediate rolling, bending is performed so that the flange portion of the first shape is linear, curved or bent inward, and has a second shape whose height dimension is the height of the product. A method for manufacturing a steel sheet pile. 2. The method for manufacturing a steel sheet pile according to claim 1, wherein the rolling pass in which the bending is performed in the finish rolling is a rolling pass using a web guide on the entry side of the rolling. The web guide has, in a cross-section perpendicular to the rolling direction, a web guide top width equal to or narrower than the bottom width of the material web after the final rolling pass of the intermediate rolling, and the final rolling pass of the intermediate rolling. 3. The method of manufacturing a steel sheet pile according to claim 2, wherein the angle between the top surface of the web guide and the side surface of the web guide is equal to the angle formed by the joint between the subsequent material web and the flange. 4. The method for manufacturing a steel sheet pile according to any one of claims 1 to 3, wherein in said finish rolling, claw bending is performed in a rolling pass subsequent to a rolling pass in which said bending is performed. 5. The method for manufacturing a steel sheet pile according to claim 4, wherein preforming for claw bending is performed on the delivery side of a rolling pass in which said bending is performed in said finish rolling, and then said claw bending is performed. A rolling equipment train for manufacturing steel sheet piles, in which a heating device, a roughing mill, an intermediate rolling mill and a finishing mill are arranged in this order,
The rough rolling mill, the intermediate rolling mill, and the finishing rolling mill are rolling mills each provided with upper and lower rolls engraved with grooves,
At least part of the caliber of the intermediate rolling mill is a caliber engraved so that the height of the caliber is smaller than the height of the product, and the flange portion has a first shape that curves or bends outward,
A part of the caliber of the finishing rolling mill cuts the flange portion of the first shape into a straight shape, or bends or bends inward into a second shape whose height dimension is the height of the product. A row of rolling equipment for manufacturing steel sheet piles, which is a set of grooves.

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