JP2009119513A - Method for hot-rolling steel sheet pile, and hot-rolling machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a large-sized hat-shaped steel sheet pile having the effective width of about 900 mm by stable hot rolling. <P>SOLUTION: When rolling a steel sheet pile 1 having arm parts 1a composed of a straight line part and claw parts for fitting to the end part of the arm part on the respective both sides of a flange 1f of a roughly U-shaped steel sheet pile 1 which is provided with a web 1w and flanges 1f on both sides, rolling is performed by constricting the upper and lower surfaces of the web 1w and the side faces of the flanges 1f and further restricting the upper and back surfaces of the arm parts 1a with a hot-rolling machine where a first guide which comes in contact with the web 1w and the flanges 1f arranged on the inside of corner parts where the web 1w and the flanges are crossed and a second guide for putting the web 1w between itself and the first guide is arranged in the upper part of the web 1w and a third guide for restricting the arm parts from up and down is arranged. The hat-shaped steel sheet pile is stably rolled while effectively suppressing the generation of twist, vertical camber and lateral bend. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a hot rolling method for steel sheet piles and a hot rolling mill used for the hot rolling, and more specifically, a hat-shaped steel having a claw portion serving as a left-right asymmetric joint used for construction work in civil engineering and construction fields. The present invention relates to a method of hot rolling a sheet pile and a hot rolling mill used for the rolling.

  In the formation of a wall using a conventional U-shaped steel sheet pile, the construction period may be long because the steel sheet pile must be placed upside down for each sheet. In addition, since the wall thickness (width) is larger than the construction method using small H-section steel, it is necessary in the suburbs of cities where close construction with adjacent land is required from the viewpoint of effective use of land. Not suitable for construction.

In order to solve such problems, the applicant has disclosed a U-shaped steel sheet pile (hat-shaped steel sheet pile) having a completely new asymmetric joint in Patent Document 1.
Japanese Patent Laid-Open No. 5-140928

Moreover, the applicant disclosed the method of manufacturing the U-shaped steel sheet pile (hat-shaped steel sheet pile) which has the said asymmetrical joint by hot rolling in patent documents 2-4.
JP-A-8-117801 Japanese Patent Laid-Open No. 10-71401 JP 2001-15002 A

Recently, as shown in FIG. 4, a large hat-shaped steel sheet pile 1 having an effective width (distance between the shaft centers of the left and right joints) L of 900 mm and an effective height H of 230 mm or 300 mm has been developed. The manufacturing method is disclosed in Patent Documents 5 and 6. In FIG. 4, 1w is a web, 1f is a flange, 1a is an arm portion, and 1c is a claw portion.
JP 2005-14496 A Japanese Patent No. 3709898

  However, when hot-rolling the large hat-shaped steel sheet pile, since the width of the material to be rolled is 900 mm to 1000 mm, compared with hot rolling a conventional steel sheet pile having an effective width of 600 mm or less. The rolling load is increased by about 1.5 to 2 times.

  Therefore, the load acting on the rolling roll is increased accordingly, and the wear of the rolling roll is increased. In addition, if the rolling roll is worn unevenly in the width direction of the hole mold, the product shape will be different on the left and right, so the crop shape during rolling will also be asymmetric and the contact start position on the rolling roll will be different on the left and right. It will be.

  Furthermore, the temperature of the material to be rolled during rolling is not uniform in the width direction, and the high temperature region and the low temperature region tend to be unevenly distributed in the surface layer and the cross section. In particular, roll cooling water during rolling tends to stay in the left and right arms of the hat-shaped steel sheet pile, and the elongation of the rolling material in the rolling direction is uniform in the width direction because the arms are likely to become low temperature. Not.

  In general, the high temperature range is easy to stretch during rolling, while the low temperature range is difficult to stretch during rolling, causing the material to be rolled to warp up and down, bend left and right, or twist on the exit side of the rolling mill. Unstable phenomena are likely to occur.

  Such a tendency is remarkable in intermediate rolling and finish rolling in which the rolling temperature tends to be lower than that in rough rolling.

  The problem to be solved by the present invention is that, particularly in hot rolling of large hat-shaped steel sheet piles having claw portions that are asymmetrical joints with arms on the left and right sides, and an effective width of around 900 mm, especially intermediate rolling and finishing During rolling, an unstable phenomenon is likely to occur such that the material to be rolled is warped up and down, bent left and right, or twisted on the exit side of the rolling mill.

  The present invention is a hot rolling method capable of manufacturing a large hat-shaped steel sheet pile having a claw portion that is an asymmetric joint with an arm portion on the left and right sides, particularly having an effective width of about 900 mm, by stable hot rolling. And it aims at providing the hot rolling mill used for the rolling.

That is, the hot rolling method of the steel sheet pile of the first invention is as follows:
In a method for hot rolling a web and a generally U-shaped steel sheet pile with flanges on both sides thereof,
A first guide that contacts the web and the flange is disposed inside the corner portion where the web and the flange intersect,
In the upper part of the web, by the hot rolling mill for the steel sheet pile according to the first aspect of the present invention, which is characterized in that a second guide for sandwiching the web with the first guide is arranged.
The main feature is that the upper and lower surfaces of the web and the side surface of the flange are restrained and rolled.

Moreover, the hot rolling method of the steel sheet pile of the second invention is as follows:
A steel sheet pile having a web portion and a substantially U-shaped steel sheet pile provided with flanges on both sides of the web, and arm portions formed of straight portions on both sides of the flange portion, and claw portions for fitting at end portions of the arm portions. In the method of hot rolling,
The hot-rolled steel sheet pile according to the second aspect of the present invention is characterized in that a third guide for restraining the arm portion from above and below is further arranged on the steel sheet pile hot rolling mill according to the first aspect of the present invention. By rolling mill,
Furthermore, the main feature is that the upper and lower surfaces of the arm portion are restrained and rolled.

  In the first aspect of the present invention, the upper and lower surfaces of the web and the side surface of the flange are constrained and rolled, and the web and flange are twisted and warped in the vertical direction on the delivery side of the hot rolling mill (hereinafter referred to as vertical warping). It is possible to effectively suppress bending in the left-right direction (hereinafter referred to as left-right bending).

  Further, in the second aspect of the present invention, in which the upper and lower surfaces of the arm portion are restrained and rolled, the left and right bending of the arm portion can be effectively suppressed.

  In the description of the present invention, “up and down” refers to a linear direction connecting the axial centers of both rolling rolls in a double rolling roll. “Left and right” refers to the axial direction of the two rolling rolls.

According to the present invention, the following effects can be obtained.
(1) During hot rolling of a hat-type steel sheet pile, it is possible to effectively suppress the occurrence of twisting, up-down warping, and left-right bending and stably rolling.
(2) With the optimal arrangement of the guide, the weight of the entire guide can be reduced, and the manufacturing cost of the guide can be reduced.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
Used in the hot rolling process of hat-shaped steel sheet piles having an effective width of 600 mm and 900 mm, as shown in FIG. 5, only the upper and lower portions of the web 1w and the lower portions of the arm portions 1a formed on both sides of the flange 1f are restrained. The conventional guide 2 cannot prevent twisting, vertical warping, and left / right bending during rolling.

  In order to solve this problem, the inventor constrains the upper and lower surfaces of the web and the side surface of the flange, and constrains the upper and lower surfaces of the arm portion, which is the greatest feature of the hat-shaped steel sheet pile, to prevent the twist and the upper and lower It was found that it is most effective in suppressing warping and left / right bending.

The present invention has been made based on the above findings,
The first aspect of the present invention is
When rolling a U-shaped steel sheet pile with flanges on both sides of the web hot,
A first guide that contacts the web and the flange is disposed inside the corner portion where the web and the flange intersect,
On the upper part of the web, the steel sheet pile hot rolling mill according to the first aspect of the present invention in which the second guide for sandwiching the web with the first guide is disposed,
The upper and lower surfaces of the web and the side surface of the flange are restrained and rolled.

The second aspect of the present invention
A steel sheet pile having a web portion and a substantially U-shaped steel sheet pile provided with flanges on both sides of the web, and arm portions formed of straight portions on both sides of the flange portion, and claw portions for fitting at end portions of the arm portions. When rolling hot,
In the steel sheet pile hot rolling mill of the first aspect of the present invention, a steel sheet pile hot rolling mill of the second aspect of the present invention in which a third guide for restraining the arm portion from above and below is further disposed.
Further, the upper and lower surfaces of the arm portion are restrained and rolled.

  FIG. 1 shows an example of a hot rolling mill 11 according to the present invention. The hot rolling mill 11 according to the present invention has an Guides 21a to 21c for restraining the rolled material from above and below are installed.

  For example, in the example shown in FIG. 1, a plate-shaped first guide 21a that comes into contact with the web and the flange is disposed inside the corner portion where the web and the flange intersect, and the first guide 21a is disposed at the upper portion of the web. A plate-shaped second guide 21b to be sandwiched is disposed, and a plate-shaped third guide 21c for restraining the arm portion from above and below is further disposed.

  That is, the first to third guides 21a to 21c restrain the upper and lower surfaces of the web and the side surfaces of the flange, and the upper and lower surfaces of the arm portion, thereby suppressing twisting, vertical warping, and lateral bending of the material to be rolled. is doing.

  As shown in FIG. 1 (b), the first to third guides 21a to 21c are fixed via rest bars 13a and 13b so that they do not come off due to contact with the material to be rolled or vibration during rolling. The rolling mill main body and the respective guides 21a to 21c are brought into contact with the upper roll 12a and the lower roll 12b using the turnbuckles 14a and 14b, respectively.

  Since the tips of the first to third guides 21a to 21c may be broken at the time of contact with the material to be rolled, it is desirable to grind them so as to become familiar with the hole shape of the rolls 12a and 12b.

  Further, in the above example, a taper along the flange side surface is attached to the corner portion where the web and the flange of the first guide 21a intersect to restrain the flange side surface. It is free to taper the portions and the second and third guides 21b and 21c.

  Moreover, since the 1st guide 21a tends to receive the force from the left-right direction at the time of rolling, and the 1st guide 21a may fall down, it can connect the adjacent 1st guides 21a by welding etc. desirable. This also applies to the second and third guides 21b and 21c.

The present invention will be described more specifically.
In the rolling line shown in FIG. 2, a continuous casting slab having a width of 1000 mm × thickness of 250 mm is heated to 1300 ° C. in a heating furnace 31, and a rough rolling mill 32 composed of a plurality of passes using a not-shown hole-type roll. Breakdown rolling was performed.

Thereafter, an intermediate rolling mill 33 composed of upper and lower double rolls having the hole shape shown in FIGS. 3 (a) and 3 (b), and a finish rolling mill 34 having the hole shape shown in FIGS. 3 (c) and 3 (d). Each roll was rolled from one pass to a plurality of passes to produce the SP-10H product shown in FIG. 2 denotes a tongue cut saw installed between the rough rolling mill 32 and the intermediate rolling mill 33.
The rolling pass schedule and rolling conditions of the examples of the present invention are shown in Table 1 below.

  According to the present invention, the material to be rolled can be guided to the roll hole mold by the first to third guides 21a to 21c, and the rolling has been completed without causing twisting, vertical warping, and right / left bending. The effectiveness of the first to third guides 21a to 21c was confirmed from the fact that the first to third guides 21a to 21c used for rolling had traces due to material contact.

  The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

  For example, the first to third guides 21a to 21c are not limited to a plate shape, and may be a plurality of rod-shaped ones.

  In the above example, the first to third guides 21a to 21c are installed in both the intermediate rolling mill and the finish rolling mill, but the first to third guides 21a to 21c are always installed in both rolling mills. The first to third guides 21a to 21c may be installed only in either one of them. Further, the third guide 21c need not be installed.

It is a figure which shows an example of the hot rolling mill of this invention, (a) is a figure which shows the arrangement position of the 1st-3rd guide with respect to a roll hole type | mold, (b) is AA sectional drawing of (a) figure. is there. It is a figure which shows the hot rolling line of the steel sheet pile to which this invention is applied. It is a figure which shows the arrangement position of the 1st-3rd guide with respect to the roll hole type | mold for hot rolling of the steel sheet pile of this invention, (a) is an intermediate rolling mill front surface, (b) is an intermediate rolling mill rear surface, (c) is (D) is a view seen from the rear face of the finish rolling mill. It is a product drawing of the hat-shaped steel sheet pile concerning this invention, (a) is SP-10H, (b) is SP-25H. It is a figure which shows the arrangement | positioning position of the guide with respect to the roll hole type | mold for hot rolling of the conventional steel sheet pile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hat-shaped steel sheet pile 1w Web 1f Flange 1a Arm 1c Claw part 21a 1st guide 21b 2nd guide 21c 3rd guide

Claims (4)

In a method for hot rolling a web and a generally U-shaped steel sheet pile with flanges on both sides thereof,
A method for hot rolling steel sheet piles, comprising rolling the upper and lower surfaces of the web and the side surfaces of the flange. A steel sheet pile having a web portion and a substantially U-shaped steel sheet pile provided with flanges on both sides of the web, and arm portions formed of straight portions on both sides of the flange portion, and claw portions for fitting at end portions of the arm portions. In the method of hot rolling,
Furthermore, the hot rolling method of the steel sheet pile of Claim 1 which restrains and rolls the upper and lower surfaces of the said arm part. In a rolling mill for hot rolling a web and a generally U-shaped steel sheet pile with flanges on both sides thereof,
A first guide that contacts the web and the flange is disposed inside the corner portion where the web and the flange intersect,
A steel sheet pile hot rolling mill characterized in that a second guide for sandwiching the web between the first guide and the first guide is disposed on the upper portion of the web. A steel sheet pile having a web portion and a substantially U-shaped steel sheet pile provided with flanges on both sides of the web, and arm portions formed of straight portions on both sides of the flange portion, and claw portions for fitting at end portions of the arm portions. In a rolling mill that performs hot rolling,
Furthermore, the 3rd guide which restrains the said arm part from the upper and lower sides is arrange | positioned, The hot rolling mill of the steel sheet pile of Claim 3 characterized by the above-mentioned.

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