CN113905831B

CN113905831B - Guide for steel sheet pile rolling mill and method for manufacturing steel sheet pile

Info

Publication number: CN113905831B
Application number: CN202080040005.0A
Authority: CN
Inventors: 大原一郎; 驹城伦哉; 小谷良文; 谷口龙磨
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2019-05-30
Filing date: 2020-05-25
Publication date: 2023-03-28
Anticipated expiration: 2040-05-25
Also published as: SG11202112280RA; KR102599706B1; JPWO2020241579A1; JP6791466B1; CN113905831A; KR20210148325A

Abstract

Provided are a guide for a steel sheet pile rolling mill, which can suppress the occurrence of guide clogging and guide defects and has excellent maintainability, and a method for manufacturing a steel sheet pile. A guide (8) for a rolling mill for a steel sheet pile (1) is provided on the inlet side of the rolling mill (e.g., a finishing mill (6)) having upper and lower rolls engraved with a pass (e.g., a K1 pass (71)) corresponding to the shape of the steel sheet pile (1), the pass having a first portion (711) for rolling a web and a pair of second portions (712) for rolling a pair of flat portions as viewed in the rolling direction, the guide (8) being provided with a pair of roll guides (81) and a web guide (82), the pair of roll guides (81) having at least one roll (812) which is provided on the first portion (711) side of the pair of second portions (712) and is rotatable in the rolling direction as viewed in the rolling direction, and guiding the flat portion of a material to be rolled to the pass, the web guide (82) being provided on the pair of second portion (712) side of the first portion (711) and guiding the web of the material to the pass as viewed in the rolling direction.

Description

Guide for steel sheet pile rolling mill and method for manufacturing steel sheet pile

Technical Field

The present invention relates to a guide for a steel sheet pile rolling mill and a method for manufacturing a steel sheet pile.

Background

Steel sheet piles such as hat-type steel sheet piles are used as retaining members in civil engineering, for example. The hat-shaped steel sheet pile has the characteristics that the effective width is 900mm, the left and right asymmetrical joint shapes are formed, and the embedded part is positioned at the outermost edge of the wall body. Accordingly, compared to conventional steel sheet piles having a width of 600mm (hereinafter, also referred to as width 600 steel sheet piles), there are advantages such as a shortened construction period and an improved rigidity as a wall body, and the variety replacement from the width 600 steel sheet pile to the hat type steel sheet pile is advancing.

< problems of burning, sticking and poor discharge >

However, when the hat-shaped steel sheet pile having an excessively wide width and an asymmetric shape is hot-rolled, since the rolling load and the temperature variation in the width direction are increased as compared with the conventional steel sheet pile, unstable phenomena such as seizure and poor discharge due to deterioration of the biting posture in front of the rolling mill are likely to occur. Here, the hot scratch (hot scratch) refers to a shape defect that occurs when a rolled material bites into a roll while being deviated in the width direction or the vertical direction, and a part of the rolled material is peeled off and pressure-bonded to the roll, and the pressure-bonded portion is transferred to the surface of the rolled material. The discharge failure (exit defect) means that the rolled material is out of the production line (line out) or cannot proceed to the next pass due to bending in the width direction, warping in the vertical direction, twisting, or the like of the rolled material, and the rolling is stopped.

To address such a problem, for example, patent document 1 discloses the following method: the first guide in contact with the web and the flange, the second guide sandwiching the web together with the first guide, and the third guide restraining the arm portion from above and below are disposed on the inlet side and the outlet side of the rolling mill, respectively, thereby stabilizing the biting posture and the discharging posture.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2009-119513

Disclosure of Invention

Problems to be solved by the invention

However, in the method disclosed in patent document 1, since a plurality of friction guides are arranged on each of the inlet side and the outlet side of the rolling mill, and the rolled material is excessively restrained in the vertical direction, there is a possibility that guide clogging (guide clogging) or guide defect (guide flap) occurs. Further, since the guide is provided at many positions, such as the upper and lower surfaces of the web, the inner sides of the corner portions between the web and the flange, and the upper and lower surfaces of the arm portion, the guide structure becomes complicated, and maintenance becomes difficult.

The present invention has been made in view of the above problems, and an object thereof is to provide a guide for a steel sheet pile rolling mill and a method for manufacturing a steel sheet pile, which can suppress occurrence of guide clogging and guide defects and have excellent maintainability.

Means for solving the problems

According to one aspect of the present invention, there is provided a guide for a rolling mill for a steel sheet pile, which is provided on an inlet side of the rolling mill during rolling of the steel sheet pile, and which has a cross-sectional shape orthogonal to a longitudinal direction, the guide having: a web extending in one direction; a pair of flanges connected to both ends of the web in the one direction and extending obliquely with respect to the one direction; and a pair of flat portions connected to end portions of the pair of flanges on a side not connected to the web and having flat portions extending in the one direction, the rolling mill having upper and lower rolls engraved with a hole pattern corresponding to a shape of the steel sheet pile, the guide comprising: a web guide that restrains a web corresponding portion corresponding to the web in the material being rolled from one direction in the vertical direction and guides the material to the pass; and a pair of roll guides having one or more rolls rotatable in a rolling direction, the pair of roll guides being constrained in a flat portion corresponding to the flat portion in the material from another direction in an up-down direction and guiding the material to the pass.

According to an aspect of the present invention, there is provided a method for manufacturing a steel sheet pile, wherein a cross-sectional shape of the steel sheet pile orthogonal to a longitudinal direction has: a web extending in one direction; a pair of flanges connected to both sides of the web and extending obliquely with respect to the one direction; and a pair of flat portions connected to one side of the pair of flanges that is not connected to the web and having flat portions extending in the one direction, wherein the rolling process of the steel sheet pile includes: the guide of the steel sheet pile rolling mill is installed on the inlet side of the rolling mill having a pass corresponding to the shape of the steel sheet pile, and the steel sheet pile is rolled by the rolling mill.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one aspect of the present invention, there are provided a guide for a steel sheet pile rolling mill and a method for manufacturing a steel sheet pile, which can suppress occurrence of guide clogging and guide defects and have excellent maintainability.

Drawings

Fig. 1 is a schematic view showing a sectional shape of a hat type steel sheet pile.

Fig. 2 is an explanatory diagram showing the equipment configuration of the rolling facility.

Fig. 3 is a partial sectional view showing a finishing mill.

Fig. 4 is a front view showing a guide provided to the finishing mill.

Fig. 5 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A' of fig. 4.

Fig. 6 is a schematic view showing a sectional shape of a U-shaped steel sheet pile.

Detailed Description

In the following detailed description, embodiments of the invention are illustrated and described in numerous specific details for a thorough understanding of the invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, the drawings show known configurations and devices in schematic diagrams for the sake of simplicity.

< Rolling Mill >

A rolling facility according to an embodiment of the present invention will be described with reference to fig. 1 to 2. The rolling facility 2 is a facility for manufacturing the steel sheet pile 1 by rolling a rectangular slab or the like as a raw material with a plurality of rolling mills. In the present embodiment, as shown in fig. 1, the steel sheet pile 1 is a hat-shaped steel sheet pile 1A having the same cross-sectional shape perpendicular to the longitudinal direction and formed into a hat shape. The hat type steel sheet pile 1A has a cross-sectional shape including a web 11, a pair of flanges 12, a pair of arm portions 13, and a pair of joint portions 14. The web 11 is a portion extending in one direction (the left-right direction in fig. 2, hereinafter also referred to as the "left-right direction"). The pair of flanges 12 are connected to both ends of the web 11 in the left-right direction, and extend obliquely with respect to the left-right direction. In the example shown in fig. 1, the pair of flanges 12 extend obliquely so that end portions on the opposite side to the web 11 are positioned lower in the vertical direction (the vertical direction in fig. 1, the direction orthogonal to the horizontal direction). The pair of arm portions 13 are connected to the side of the pair of flanges 12 that is not connected to the web 11 and extend in the left-right direction. The pair of joint portions 14 are portions connected to the sides of the pair of arm portions 13 not connected to the flanges 12, and have a hook-like shape that opens to the upper side or the lower side in the up-down direction. The pair of joint portions 14 are portions to be connected to another steel sheet pile by being fitted into joint portions of another steel sheet pile when used as a steel sheet pile. In the present embodiment, the arm portion 13 and the joint portion 14 are also collectively referred to as a flat portion 15. The flat portion 15 is formed in the steel sheet pile 1 so as to be connected to the end portion of the flange 12 on the side not connected to the web 11, and has a flat portion extending in the left-right direction. In the present embodiment, the arm portion 13 is a flat portion of the flat portion 15. The distance between the pair of joint portions 14 indicated by W in fig. 1 is referred to as an effective width, and the distance in the vertical direction from the flange 12 to the arm portion 13 indicated by H in fig. 1 is referred to as an effective height.

As shown in fig. 2, in the rolling facility 2, a rectangular slab as a raw material heated to a predetermined temperature by the heating furnace 3 is rolled in sequence by a roughing mill (BD) 4, a middle rolling mill (SR) 5, and a finishing mill (SF) 6, thereby manufacturing a hat type steel sheet pile 1A.

The roughing mill 4 roughly forms the rectangular slab heated by the heating furnace 3 into a rough steel sheet having a substantially hat-shaped cross section orthogonal to the longitudinal direction. The roughing mill 4 has a set of rolls consisting of an upper roll and a lower roll. The roll group is engraved with a plurality of passes (for example, a Box pass, a K8 pass, and a K7 pass) called calibers (calibers).

The intermediate rolling mill 5 rolls the material rolled by the roughing mill 4, and has two roll sets each having a plurality of passes engraved therein. For example, two passes are engraved in each roll group of the intermediate rolling mill 5, and four passes (for example, K6 pass to K3 pass) are engraved as a whole. Here, for example, when the Box pass and the K8 to K3 passes are provided in the roughing mill 4 and the intermediate mill 5, the pass shape (the shape of the roll gap) of the Box pass as viewed from the rolling direction is substantially square, and the pass shapes of the K8 to K3 passes as viewed from the rolling direction are hat-shaped. Further, the roll gap and the shape of the K8 pass to K3 pass were set as follows: the pass used in the latter half of rolling is such that the thickness of the material to be rolled becomes thinner and the cross-sectional shape becomes closer to the shape of the product.

The finishing mill 6 rolls the material rolled by the intermediate rolling mill 5, and has a roll group engraved with two passes. That is, the finishing mill 6 has two pass types, which are referred to as a K2 pass and a K1 pass.

The finishing mill 6 is explained in detail with reference to fig. 3. As shown in fig. 3, the finishing mill 6 includes an upper roll 61 and a lower roll 62 which are disposed as one roll group and are opposed to each other in the vertical direction which is the vertical direction. The upper and

lower rolls

61 and 62 are engraved with K2 pass 71 and K1 pass 72 corresponding to the product shape of the hat type steel sheet pile 1A. The K2 pass 71 is a pass for rolling a material so that the plate thickness becomes the product thickness with respect to the cross-sectional shape of the material rolled by the intermediate rolling mill 5. The K1 pass 72 is a pass in which the joint portion 14 of the material rolled by the K2 pass 71 is bent. In the K2 groove 71, the portion where the web 11 of the hat-shaped steel sheet pile 1A is rolled is defined as a first portion 711, the portion where the arm 13, which is the flat portion of the flat portion 15, is rolled is defined as a second portion 712, and the portion where the flange 12 is rolled is defined as a third portion 713. That is, the K2 pass 71 has a first portion 711, a second portion 712, and a third portion 713 as the shape of the nip (the gap between the upper roller 61 and the lower roller 62) viewed from the rolling direction.

On the upstream side of the K2 pass 71 of the finishing mill 6 (the upstream side in the rolling direction, the inlet side of the material into the finishing mill 6), a guide 8 is provided for guiding the rolled material to the K2 pass 71. As shown in fig. 4 and 5, the guide 8 includes a pair of roller guides 81, a web guide 82, an upper support beam 83, and a lower support beam 84.

The pair of roller guides 81 has a guide frame 811 and two rollers 812, respectively. The pair of roller guides 81 is a guide for guiding the flat portion of the material to be rolled, i.e., the portion corresponding to the arm portion, to the K2 pass 71 while restraining it from above. The pair of roller guides 81 are provided above the pair of second portions 712 when viewed from the rolling direction, i.e., on the first portion 711 side of the second portions 712 in the direction orthogonal to the extending direction, in order to guide the flat portions of the material.

The guide frame 811 is a member that supports the two rollers 812, and is fixed to the upper support beam 83. As shown in fig. 5, the upstream end (left side in fig. 5) of the guide frame 811 in the rolling direction has a shape cut away obliquely so that the lower end is positioned above the upstream end in the rolling direction. By adopting such a shape, even when the upward warping of the leading end of the material to be rolled is large, the material can be guided to the K2 pass 71. The two rolls 812 are fixed to the guide frame 811 so as to be rotatable in the rolling direction of the material to be rolled, and are arranged in a row in the rolling direction.

As shown in fig. 4, the pair of roller guides 81 are respectively arranged on the first part 711 side (the web side of the hat shape, the upper side in fig. 4) of the second part 712 of the K2 pass 71 when viewed from the rolling direction. The lower ends of the two rolls 812 may be located above the nip between the upper roll 61 and the lower roll 62 when viewed in the rolling direction of the pair of roll guides 81, and a predetermined gap d2 is preferably provided between the two rolls 812 and the second portion 712 of the K2 pass 71. As shown in fig. 4, the gap d2 is a distance in the vertical direction between the lower end of the roll 812 and the upper end of the nip of the second part 712 of the K2 pass 71 (the lower end of the upper roll 61) when viewed from the rolling direction. The clearance d2 is a distance of the nip at the second portion 712 of the K2 pass 71, and is preferably about the same as a separation distance (a distance of the nip) between the upper roller 61 and the lower roller 62 at the second portion 712 of the final rolling pass in the K2 pass 71. Here, the final rolling pass is a final rolling pass when a plurality of passes are performed in the pass, and is a single pass when only a single pass is performed in the pass. That is, the distance of the nip in the final pass is the same as the plate thickness after rolling of the material to be rolled in the pass. The gap d2 is preferably 40% to 120% of the distance of the nip at the second part 712 of the K2 pass 71, and is preferably the same as the distance of the nip at the second part 712 of the K2 pass 71. The roll gap at the second portion 712 of the K2 pass 71 corresponds to the thickness of the arm portion 13 of the product of the hat type steel sheet pile 1A to be rolled. In the case where the gap d2 is less than 40% of the distance of the nip at the second portion 712 of the K2 pass 71, since the gap d2 is excessively small, the possibility of occurrence of clogging of the raw material becomes high. On the other hand, when the gap d2 exceeds 120% of the distance of the nip at the second portion 712 of the K2 pass 71, the gap d2 is too large, and therefore, the raw material cannot be guided to the nip, and a biting failure may occur.

The web guide 82 is a friction guide having a shape along the first portion 711 and the third portion 713 of the K2 groove 71, that is, along the shapes of the web 11 and the flange 12 of the hat-shaped steel sheet pile 1A, as viewed from the rolling direction. The web guide 82 guides the web and the flange of the material to be rolled to the K2 pass 71 while restraining the portions corresponding to the web and the flange from below. As shown in fig. 5, the web guide 82 has an upstream end in the rolling direction cut out at an angle such that the upper end is positioned on the lower side as it becomes the upstream side in the rolling direction. By adopting such a shape, even when the downward warping of the leading end of the material to be rolled is large, the material can be guided to the K2 pass 71.

The web guide 82 is disposed below the first portion 711 and the third portion 713 of the K2 pass 71, that is, on the second portion 712 side (the arm portion side of the hat-shaped portion, the lower side in fig. 4) of the first portion 711 in the direction orthogonal to the extending direction, when viewed from the rolling direction.

The upper end of the web guide 82 itself may be located below the nip between the upper and

lower rolls

61 and 62 when viewed in the rolling direction, and preferably, predetermined gaps d1 and d3 are provided between the web guide 82 and the first and

third portions

711 and 713 of the K2 groove 71, respectively. As shown in fig. 4, the gap d1 is a distance in the vertical direction between the upper end of the portion of the web guide 82 corresponding to the web and the lower end of the nip of the first portion 711 (the upper end of the lower roll 62) when viewed from the rolling direction. The clearance d3 is a distance in the vertical direction between the upper end of the portion of the web guide 82 corresponding to the flange (the portion of the upper end extending obliquely with respect to the left-right direction when viewed from the rolling direction) and the third portion 713 of the lower end of the nip of the third portion 713 of the K2 pass 71 (the upper end of the lower roll 62) when viewed from the rolling direction. The gap d1 is preferably 40% or more and 120% or less of the distance of the nip at the first portion 711 of the K2 pass 71, and the gap d3 is preferably 60% or more and 180% or less of the distance of the nip at the third portion 713. The roll gaps at the first portion 711 and the third portion 713 of the K2 pass 71 correspond to the thicknesses of the web 11 and the flange 12, respectively, of the product of the rolled hat type steel sheet pile 1A. By setting the gaps d1 and d3 to the above range, the same effect as the gap d2 can be obtained.

The upper support beam 83 is a member that supports the pair of roller guides 81, and extends in the left-right direction. The upper support beam 83 is fixedly arranged to the housing or bearing housing of the rolling mill in which the guide 8 is arranged. The upper support beam 83 is provided above the K2 pass 71 as viewed in the rolling direction, and fixes the guide frames 811 of the pair of rollers 81.

The lower support beam 84 is a member that supports the web guide 82 and extends in the left-right direction. The lower support beam 84 is fixedly arranged to the housing or bearing housing of the rolling mill on which the guide 8 is arranged. Further, the lower support beam 84 is provided below the K2 pass 71 as viewed in the rolling direction, and fixes the web guide 82.

< method for producing Steel sheet pile >

Next, a method for manufacturing the steel sheet pile 1 of the present embodiment will be described. In the present embodiment, a rectangular slab heated to a predetermined temperature by a heating furnace 3 is rolled in sequence by a roughing mill 4, an intermediate rolling mill 5, and a finishing mill 6, thereby manufacturing a hat-shaped steel sheet pile 1A having a cross-sectional shape shown in fig. 1. The step of rolling by each rolling mill is also referred to as a rolling step.

In the rolling by the roughing mill 4 and the intermediate mill 5, the rolling of the material is performed a plurality of times by each pass of each mill. In the roughing mill 4, when the Box pass is used as described above, the rectangular slab is spread-rolled by the Box pass, and then the slab is bent and reduced in thickness by the K9 pass.

In the rolling by the finishing mill 6, the material rolled by the intermediate rolling mill 5 is rolled by the K2 pass 71 and then by the K1 pass 72. In this case, the number of rolling passes in the K2 pass 71 and the K1 pass 72 is set to one pass.

In the rolling with the K2 pass 71, the material is bitten into the K2 pass 71 by the guide 8. At this time, the raw material is constrained from the upper side by the pair of roller guides 81, and is constrained from the lower side by the web guide 82. This allows the biting posture of the material into the K2 groove 71 to be maintained within a predetermined range, and even when the material has an upper warp larger than the gap d1 or a lower warp larger than the gap d3, the leading end of the material can be bitten into the K2 groove 71. Further, since the material is restrained with respect to the left-right direction by the web guide 82, the biting posture into the K2 hole 71 is maintained within a predetermined range corresponding to the gap d2. Therefore, even when the material is bent in the left-right direction, the leading end of the material can be caused to bite into the K2 hole pattern.

< modification example >

The present invention has been described above with reference to specific embodiments, but the present invention is not intended to be limited by these descriptions. The embodiments disclosed and other embodiments of the present invention including various modifications will be apparent to those skilled in the art from consideration of the specification of the present invention. Therefore, the embodiments of the invention described in the claims should be construed to cover the embodiments including these modifications described in the specification alone or in combination.

For example, in the above embodiment, the steel sheet pile 1 is the hat type steel sheet pile 1A, but the present invention is not limited to this example. The steel sheet pile 1 may be a steel sheet pile having another cross-sectional shape, as long as it includes a web, a flange, and a flat portion which is a flat portion. For example, the steel sheet pile 1 may be a U-shaped steel sheet pile 1B having a cross-sectional shape shown in fig. 6. The U-shaped steel sheet pile 1B is a steel sheet pile having a U-shaped cross section, and as shown in fig. 6, includes a web 11, a pair of flanges 12, and a pair of joint portions 14. The web 11 and the pair of flanges 12 are the same as the hat type steel sheet pile 1A. The pair of joint portions 14 are portions connected to the sides of the pair of flanges 12 not connected to the web 11, and have flat portions extending in the left-right direction at the lower ends thereof as shown in fig. 6. In this U-shaped steel sheet pile 1B, there is a flat portion (claw bottom portion 142 in fig. 6) corresponding to the flat portion 15 in the above-described embodiment in the joint portion 14, and the claw bottom portion 142 is restrained from above by a pair of roller guides similar to those in the above-described embodiment, so that the biting posture is stabilized. In the present invention, the second portion is a portion of the roll gap of the rolling claw bottom portion 142 in the pass provided with the guide. Therefore, in the case of the U-shaped steel sheet pile 1B, the second location of the pass becomes a location of a nip of the claw bottom 142 of the rolled joint portion extending in the left-right direction. The cross-sectional shape of the U-shaped steel sheet pile 1B shown by the solid line in fig. 6 shows the cross-sectional shape after the final rolling (rolling with the K1 pass), and in the rolling before the final rolling (rolling with the pass before the K2 pass), in order to roll the claw 141 of the joint part 14 into a shape opened outward as shown by the broken line, the claw bottom 142 is guided to the pass by the roller 812 by setting the gap d2 and providing the roller 812 as described above.

In the above embodiment, the two rollers 812 are provided in the roller guide 81, but the present invention is not limited to this example. At least one roller 812 provided in one roller guide 81 may be used.

In the above embodiment, the web guide 82 is a friction guide, but the present invention is not limited to this example. The web guide 82 may be a roller guide provided with rollers at positions in contact with the web or flange of the raw material. In this case, the roller may be the same as the roller 812 in the roller guide 81.

In the above embodiment, the orientation of the rolled steel sheet pile 1 is set such that the web 11 is the upper side in the vertical direction and the flat portion 15 is the lower side in the vertical direction. For example, the orientation of the rolled steel sheet pile 1 may be reversed from the top to bottom direction of the above-described embodiment. In this case, the direction in which the roller guide 81 and the web guide 82 restrain the raw material is reversed from the above embodiment.

In the above embodiment, the guide 8 is provided in the K2 groove 71 of the finishing mill 6, but the present invention is not limited to this example. For example, the guides may be provided on the K1 pass 72 of the finishing mill 6 or on another pass of the roughing mill 4 or the intermediate mill 5. In this case, in the case of a rolling mill that performs reversible rolling in which the rolling direction is changed as rolling in a plurality of passes, such as the roughing mill 4 or the intermediate mill 5, the guides 8 may be provided on both sides of the roll group in the conveying direction.

< effects of the embodiment >

(1) A guide 8 of a rolling mill for a steel sheet pile 1 according to an aspect of the present invention is provided on an entrance side of a rolling mill (for example, a finishing mill 6) in rolling the steel sheet pile 1, the steel sheet pile 1 having a web 11 extending in one direction, a pair of flanges 12 connected to both ends of the web 11 in the one direction and extending obliquely with respect to the one direction, and a pair of flat portions 15 connected to ends of the pair of flanges 12 on a side not connected to the web 11 and having flat portions extending in the one direction, the rolling mill having upper and lower rolls on which a pass (for example, a K2 pass 71) corresponding to a shape of the steel sheet pile 1 is engraved, and the guide 8 includes: a web guide 82 that guides the rolled material to the pass while restraining a web corresponding portion corresponding to the web 11 in the rolled material from one direction of the vertical direction; and a pair of roller guides 81, each roller guide 81 having one or more rollers 812 rotatable in a rolling direction, and guiding the material to the hole pattern while restraining the material from the other direction in the vertical direction at a flat portion corresponding to the flat portion.

According to the configuration of the above (1), the material to be rolled can be restrained in the vertical direction on the inlet side of the rolling mill. Therefore, even when the material is warped or twisted vertically, the material is conveyed to the rolling mill in an appropriate biting posture, and therefore, occurrence of a biting failure can be prevented. The guide 8 having the structure of the above (1) can bite the raw material into the pass only by the structure of the pair of roll guides 81 for restraining the flat portion from one direction in the vertical direction and the web guide 82 for restraining the web 11 from the other direction in the vertical direction on the entry side of the rolling mill. Therefore, as compared with a guide that restrains a plurality of positions in the cross section of the material on both the inlet side and the outlet side of the rolling mill as in patent document 1, the material is not excessively restrained, and therefore, it is possible to suppress the occurrence of guide clogging caused by the material clogging in the guide and guide defects caused by contact with the guide. In the structure of the above (1), since the structure in which the constraint such as the guide is reduced as compared with the guide of patent document 1, the maintainability is excellent. In the configuration of the above (1), at least the roller guide 81 is a guide mechanism of a roller type. Thus, the structure of the above (1) is superior in maintainability to the friction type guide mechanism. Further, since the guide mechanism uses the roller, the occurrence of the guide defect can be further suppressed as compared with the friction type guide mechanism. Further, the biting posture is stabilized, whereby occurrence of defective discharge, guide defects, and seizure such as twisting and vertical warping during hot rolling can be suppressed.

(2) In the structure of the above (1), a predetermined gap d2 is provided between the roll 812 and the upper end or the lower end of the pass as viewed from the rolling direction.

According to the configuration of the above (2), the occurrence of the guide clogging can be further suppressed.

(3) In the configuration of the above (2), the clearance d2 is 40% or more and 120% or less of the distance between the nips of the upper and lower rolls at the position corresponding to the rolling flat portion in the pass.

According to the configuration of the above (3), the occurrence of the guide clogging and the occurrence of the biting failure can be further reduced.

(4) In any one of the above-described structures (1) to (3), the steel sheet pile 1 is a hat type steel sheet pile 1A having a pair of arms 13 and a joint 14 as a pair of flat portions 15, the pair of arms 13 being connected to the pair of flanges 12 and extending in one direction, the joint 14 being connected to one side of the pair of arms 13 that is not connected to the pair of flanges 12, and the pair of flat portions 15 being the pair of arms 13.

According to the structure of the above (4), the biting posture can be stabilized in the hat type steel sheet pile in which the biting posture is easily deteriorated by rolling load and temperature variation in the width direction because the pile has an ultra-wide and laterally asymmetric shape.

(5) In a method for manufacturing a steel sheet pile 1 according to an aspect of the present invention, the steel sheet pile 1 has a web 11 extending in one direction, a pair of flanges 12 connected to both sides of the web 11 and extending obliquely with respect to the one direction, and a pair of flat portions 15 connected to one side of the pair of flanges 12 not connected to the web 11 and having flat portions extending in the one direction, as a cross-sectional shape orthogonal to the longitudinal direction, and when rolling the steel sheet pile 1, the method includes the following rolling steps: on the inlet side of a rolling mill having a pass corresponding to the shape of the steel sheet pile 1, a guide of the rolling mill of the steel sheet pile 1 described in any one of (1) to (4) above is installed, and rolling is performed by the rolling mill.

According to the configuration of the above (5), the same effects as those of the configurations of the above (1) to (4) can be obtained.

Examples

Next, examples carried out by the present inventors are explained. In the examples, the cap-shaped steel sheet pile 1A having an effective width W of 900mm and an effective height H of 230mm was manufactured by the rolling facility 2 shown in FIG. 2, similarly to the above-described embodiments. At this time, in the K2 pass 71 in which the final thickness rolling is performed, the guide 8 is provided on the entry side in the rolling direction. In the guide 8, as for the size of the roller 812, a roller having a diameter of 170mm and a width of 60mm is used, and the gaps d1 to d3 are the same as the distances of the nips at the first portion 711 to the third portion 713. Then, 10 stocks were continuously rolled by the rolling mill 2, and the presence or absence of the occurrence of the guide clogging, the presence or absence of the occurrence of the discharge failure, the presence or absence of the occurrence of the seizure and the presence or absence of the occurrence of the guide defect in the K2 pass 71 were confirmed.

In comparison, rolling was performed in the same rolling facility as in the example under the conditions for performing rolling without providing the guide 8 (comparative example 1) and under the conditions for performing rolling with providing the guide simulating patent document 1 (comparative example 2), and the presence or absence of the occurrence of the abnormality in the K2 pass 71 was confirmed in the same manner as in the example.

Table 1 shows the results of examples and comparative examples 1 and 2. In table 1, the "rolling order" shows 10 rolled raw materials. In table 1, "o" indicates that no abnormality occurred, that "x" indicates that abnormality occurred, and that "-" indicates that the occurrence of abnormality cannot be confirmed. The burn-in refers to a shape defect that occurs when the raw material bites into the roll while being deviated in the width direction or the vertical direction, and a part of the raw material is peeled off and pressed against the roll, and the pressed portion is transferred to the surface of the raw material. The term "discharge failure" means that the material is bent in the width direction, warped or twisted in the vertical direction, and the like, and thereby goes out of the production line or becomes unable to proceed to the next pass, and the rolling is stopped. The guide defect is a shape defect occurring on the surface of the raw material due to strong contact with the guide. In this example, the next material was rolled after the shape inspection of each material. When the seizure was confirmed by the shape inspection, the rolls of the intermediate rolling mill 5 and the finishing rolling mill 6 were inspected, and the rolls were dressed by a grinding machine.

[ Table 1]

As shown in table 1, in comparative example 1, discharge failure and seizure occurred at the initial stage of rolling. In addition, seizure also occurs sporadically after rolling adjustment by roll inclination adjustment or the like. In comparative example 2, although the guide clogging occurred during the first rolling, no discharge failure occurred. Further, a guide defect is generated at the initial stage of rolling, and the generation of the guide defect disappears after adjustment.

In contrast, in the examples, the improvement effect was confirmed without occurrence of guide clogging, defective discharge, burning and guide defects from the first.

The present inventors performed rolling even in the intermediate rolling mill 5 under the condition that the same guide as that of the finishing mill 6 was provided. As a result, it was confirmed that the rolling by the intermediate rolling mill 5 was also able to perform the rolling without occurrence of abnormalities such as guide clogging, defective discharge, seizure, and guide defects.

Description of reference numerals

1. Steel sheet pile

1A cap type steel sheet pile

1B U-shaped steel sheet pile

11. Web plate

12. Flange

13. Arm part

14. Joint part

15. Flat part

2. Rolling mill

3. Heating furnace

4. Roughing mill

5. Intermediate rolling mill

6. Finishing mill

61. Upper roll

62. Lower roller

71 K2 hole pattern

711. The first part

712. The second part

713. The third part

8. Guide piece

81. Roller guide

811. Guide frame

812. And (3) a roller.

82. Web guide

83. Upper supporting beam

84. Lower supporting beam

Claims

1. A guide of a rolling mill for a steel sheet pile, which is provided on an inlet side of the rolling mill in rolling of the steel sheet pile,

the steel sheet pile has a cross-sectional shape orthogonal to the longitudinal direction, the cross-sectional shape including: a web extending in one direction; a pair of flanges connected to both ends of the web in the one direction and extending obliquely with respect to the one direction; and a pair of flat portions connected to ends of the pair of flanges on a side not connected to the web and having flat portions extending in the one direction,

the rolling mill is provided with an upper roller and a lower roller which are engraved with a hole pattern corresponding to the shape of the steel sheet pile,

the guide is provided with:

a web guide that restrains a web corresponding portion corresponding to the web in the material being rolled from one direction in the vertical direction and guides the material to the pass; and

and a pair of roll guides including one or more rolls rotatable in a rolling direction, the pair of roll guides being constrained to flat portion corresponding portions of the material corresponding to the flat portions from another direction in a vertical direction and guiding the material to the pass.

2. Guide of a rolling mill of steel sheet piles according to claim 1,

a predetermined gap is provided between the roll and the upper end or the lower end of the pass as viewed in the rolling direction.

3. Guide of a rolling mill of steel sheet piles according to claim 2,

the clearance is 40% to 120% of a distance between nips of the upper roller and the lower roller at a portion corresponding to the flat portion rolled in the pass.

4. The guide of a rolling mill of steel sheet piles according to any one of claims 1 to 3,

the steel sheet pile is a hat-shaped steel sheet pile having a joint portion and a pair of arm portions as the pair of flat portions, the pair of arm portions being connected to the pair of flanges and extending in the one direction, the joint portion being connected to a side of the pair of arm portions that is not connected to the pair of flanges,

the pair of flat portions is the pair of arm portions.

5. A method for manufacturing a steel sheet pile, wherein,

the steel sheet pile has a cross-sectional shape orthogonal to the longitudinal direction, the cross-sectional shape including: a web extending in one direction; a pair of flanges connected to both sides of the web and extending obliquely with respect to the one direction; and a pair of flat portions connected to a side of the pair of flanges not connected to the web and having flat portions extending in the one direction,

when the steel sheet pile is rolled, the method comprises the following rolling steps: a guide for a rolling mill of a steel sheet pile according to any one of claims 1 to 4 is provided on an inlet side of a rolling mill having a pass corresponding to a shape of the steel sheet pile, and rolling is performed by the rolling mill.