JP2703362B2 - Rolling method of U-shaped sheet pile - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for rolling a U-shaped steel sheet pile, and more particularly, to a method of rolling a U-shaped steel sheet pile with a smaller die width than a conventional method. The present invention relates to a rolling method for avoiding a limitation on a shortage of an effective body length of a rolling roll.

(Prior Art) As shown in FIG. 6, a method of rolling a U-shaped steel sheet pile is shown in FIG.
Therefore, it is known that the web 2 is roll-formed by a method in which the web 2 is tilted with a small number of holes by 8 to 10 holes, or a method in which the web 2 is straightened. Basically, the die width W of the pass in the shaping rolling by the double roll rolling machine is substantially larger than the width of the steel material of the front die, and the same can be said for the web width B in this case. However, K-1 with bending
This does not apply to the die width W in the case of (bend forming of the claw portion 12), and K-2> K-1 (see Japanese Patent Application Laid-Open No. 54-128467).
As described above, as the rolling progresses, the web width B slightly increases, but this tendency is increased in the order of the rough shaping (a), the intermediate shaping (b), and the finish shaping (c) in FIG. The amount of increase is reduced, and particularly, after K-4, between final finishes K-1, the amount is close to zero, or conversely, the next hole type is reduced. FIG. 8 shows an example thereof, wherein FIG. 8 (a) shows a steel material after K-5, and FIG. 8 (b) shows a hole shape of K-4. FIG. 8 (c) shows the rolled state of the corners 7 and 8 of the web shown in FIGS. 8 (a) and (b) in which K-5 and K-4 are superimposed on the basis of the center CL of the hole shape. Is shown. Although the web widths B are the same and the difference in the web width B is zero, the inside of the web in the hatched portion 18 corresponding to the difference in the thickness of the corner portions is still stretched.

The hole width W is expressed by adding the web width B and twice the distance f from the flange to the claw portion.
7, the web 2, the flange 11, the claw 12, and the overall width W ₀ of the product of FIG.
Is naturally determined by the relationship between the dimensional shape and the width B of the front and rear hole type and the distance f from the flange to the claw portion,
The hole width W cannot be freely changed.

(Problems to be Solved by the Invention) These prior arts do not cause a problem in manufacturing, especially if they have equipment specifications that can respond to products. However, commensurate with the full width W ₀ of the product in this, the number of roll stands or effective barrel length L of the rolling rolls shown in FIG. 10 becomes impossible to manufacture when insufficient. FIG. 10 shows an example of tandem rolling in which an intermediate hole type K-5 (dotted line) is arranged on a roll. In the rolling of section steel with a double roll rolling mill,
Vertical rolls (21, 22) is moved into the rolling time of the left-right direction (e.g., arrow Y _1, Y _two directions) the left and right flange 11 by,
A thrust collar 23 that serves as a stopper at both ends of the roll so that the thickness deviation of the claw 12 does not exceed a certain degree.
It is fundamental to arrange. In this case, some of the rolling reaction force acts in the horizontal direction of the thrust collar (usually about 30%), so it is necessary to have a thrust collar thickness to secure the strength that can withstand this. If the thickness is insufficient, the thickness of the thrust collar becomes as small as l ₁ and rolling becomes impossible.

To avoid this, if the web width B is increased in the vicinity of the final finishing roll to reduce the web width B, the web width becomes smaller as the pre-hole type, but the following problems occur. If the expansion of the web width B by rolling between the dies is increased, the plate length of the web is elongated, and the web thickness is partially reduced, and a uniform thickness cannot be obtained. At the same time, the effect of extending the flange 11 of the final hole type K-1 in FIG.
As shown in FIG.
9,20 left and right claw meat unbalance occurs. The wear of the web corner portion 17 progresses quickly and the surface properties are poor. The product quality deteriorates and the problem is not solved.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned problems of the prior art, and when rolling shaping is performed from a rectangular cross-section billet by a double roll rolling mill, a rough shaping die is used. In a rolling method in which the web is bent into a corrugated shape immediately before the final finishing die and the claws are bent and formed in the final finishing die, and the web is formed into a straight line, the center of the web between the respective die types is formed. A method of rolling a U-shaped steel sheet pile, comprising sequentially expanding and rolling a web width of up to 20 mm per hole with one to four holes until the final hole shape while keeping the wire lengths substantially equal. It is.

(Operation) Hereinafter, the present invention will be described in detail.

FIG. 1 shows an example of a mill arrangement for implementing the present invention. In the figure, 3 and 4 are coarse mills, 3 is a reversible BD mill, 4 is a coarse mill in the latter stage, 5 is an intermediate mill, 6 is a finishing mill, and 4 to 6 perform tandem rolling of one-hole, one-bath. . Note that the dashed mill indicates an unused mill.

FIG. 2 is an explanatory view of a sequence of a rolling example of a U-shaped sheet pile according to the present invention, using a rectangular cross-section steel piece, bending a web into a corrugated shape, using a shaping die, and performing rough shaping ( a) K-
9 to K-8 (BD mill 3), K-7 (later coarse mill 4), K-6 and K-5 (intermediate mill 5) for intermediate molding (b), K-4 to K-4 for final molding (c) K-1 (finishing mill 6) is sequentially rolled to produce a product. The hole width W of the finished hole type K-1 is the web width B based on the dimensions and shape of the web 2, flange 11, and claw portion 12 of the product shown in FIG.
Is determined by itself. K in this
The distance f of each hole type before -2 is substantially determined by the interrelationship between the hole types, but the web 2 of the hole type before K-2 is bent into a corrugated shape, and the web plate length l (hereinafter referred to as the web center). When the web width B is reduced by increasing the length of the web (referred to as the line length), the hole width W before K-2 can be reduced. For example, in the hole types from K-1 to K-5, the relation of the web width B is expressed as K-1>K-2>K-3>K-4> K.
In this case, the degree of curvature of the web corrugation is increased so that the center line length l of the web becomes substantially the same in each hole type, and there is no stretching effect of the web center line length between the hole types. In this state, the groove width B can be made smaller than in the prior art. Since the cumulative amount of decrease in the hole width W is naturally in the order of before K-5>K-4>K-3> K-2, the number of hole shapes for sequentially reducing the web width depends on how much the width is desired to be reduced. You just have to select

FIG. 3 shows the relationship between the web width B and the hole shape of the center line length of the web in the case of K-4 and K-3, and FIG. 3A shows the hole of K-4. Type, Fig. 3 (b) is K-
FIG. 3 (C) shows K-4 and K-3.
(A), which are superimposed on the basis of the center CL of the hole type.
(B) shows the rolled state of the corners 7 and 8 of the web. In the relationship between K-4 and K-3, the web width B is K-
3> K−4, and the bending degree of the web waveform, that is, the height h of the web, is K− such that the line length l of the web is K−3 ≒ K−4.
If the relationship of 3 <K−4 is satisfied, the web width of the corner portion of the web after rolling is apparently increased by ΔB as shown in FIG. On the other hand, the portion having a large waveform bending degree of K-4 is bent and stretched to the web shape of K-3 in the rolling process, and substantially no stretching action of the wire length of the web occurs. Here K
-4) The web width B can be reduced by ΔB.
However, there is a limit on the reduction ΔB of the web width B.

FIG. 4 shows the state at the time of the start of biting between the molds as K.
In the example of -4 and K-3, 9 and 10 are the upper roll and the lower roll of K-3, respectively. FIG. 4 (a) shows a case where the web width enlargement ΔB in K-3 is relatively large. The lower roll 10 is in contact with the flange 11 of the K-4 steel material on the surface, while the upper roll 9 is in the form of a claw. It is in an unstable state where it is in contact at point e on the upper part of the part 12. In this state, when the biting point of the claw portion of the upper roll is in one-point contact, and the gap i between the flange portion 11 and the upper roll is increased, the center of the K-4 steel material and the center of the K-3 roll are likely to be displaced. There is a possibility that the meat quantity of the portion 12 will lose the balance between the left and right, resulting in an unbalanced product of nail meat as shown in FIGS.

On the other hand, FIG. 4 (b) shows a case where ΔB is close to zero,
The lower roll 10 supports the surface contact of the flange 11 with the point g of the web 2, and the upper roll 9 contacts with a large surface from the claw portion 12 to the lower portion of the flange 11.
The roll is in a very stable and ideal biting state in which there is no possibility of left and right displacement with respect to the roll. Generally, in the ordinary rolling, the rolling is performed in the range of FIG. 4 (B) or an intermediate range between FIGS. 4 (B) and 4 (A). The possible range of ΔB can be up to Max 20 mm as a result of model experiments, but is preferably 15 mm or less in consideration of stability. Also, if the reduction allowance ΔB (expansion allowance in rolling) of the total web width B up to K-5 with respect to K-1 becomes too large, the degree of curvature h of the web waveform increases and the local roll wear of the convex portion is considered. Therefore, it is desirable to be 50mm or less.

In the groove rolling by a double roll rolling mill, a web having a shape in which a web is bent in a corrugated shape is also found (Japanese Patent Application Laid-Open No. 54-128467), which is shown in FIGS. 6 and 8. It is within the prior art of U-shaped sheet piles and is fundamentally different from the present invention.

FIG. 5 shows an example of an entrance guide for preventing the lateral displacement of the steel material with respect to the roll when the enlargement allowance ΔB in the rolling becomes large. The upper and lower friction guides 13 and 14 are provided with a flange 11 of the steel material. It is a method to prevent the left and right deviation of the steel material by installing guide rollers 15 and 16 to reduce the gap between the guide and the guide.To ensure more stable rolling, it is desirable to use such a severe guide together .

(Embodiment) Next, the present invention is applied to the rolling of a sheet pile having a width 100 mm larger than that of the conventional steel sheet pile in the mill arrangement shown in FIG.
The result of the example implemented by the method shown in FIG. 3 and FIG. 3 will be described.

The cross-sectional dimensions of rectangular steel are 470 mm wide × 1 high
Using a width of 520 mm and a height of 160 mm for 60 mm, the web width increment between dies from K-9 to K-5 applies the prior art ΔB. ΔB as shown in
The hole mold was used. As a result, with the prior art mold,
As shown by the dotted line in FIG. 10, the strength of the thrust collar 23 could not be secured, but the thrust collar thickness l ₂ = l ₁ +25 mm
The thickness was increased, and no breakage due to rolling occurred, and the strength was secured. In addition, as a result of using a severe guide as shown in FIG. 5 in consideration of the rolling stability, a good product comparable to the conventional product was obtained.

(Effects of the Invention) According to the present invention, for a steel sheet pile product to be manufactured, a plurality of hole dies are arranged on one roll when securing the number of forming dies, or one roll is put on one roll. In the case of arranging the groove shape, a remarkable effect is obtained that can effectively avoid a situation where the roll body length is insufficient and production becomes impossible.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a rolling line for implementing the present invention,
FIG. 2 is an explanatory view of a sequence for rolling a U-shaped steel according to the present invention,
FIG. 3 is an enlarged explanatory view of FIG. 2, (a) is K-4,
(B) shows an example of a diagram of the K-3 hole shape, (c) shows an example of a superposition thereof, and FIGS. 4 (a) and 4 (b) show the state at the time of the start of biting between the hole shapes in FIG. , FIG. 5 is an explanatory view of an inlet guide for performing more stable rolling in the present invention, FIG. 6 is a view showing a conventional U-shaped sheet pile rolling sequence,
FIG. 7 is a product drawing thereof, FIGS. 8 (a), (b) and (c) are enlarged explanatory views of FIG. 6, and FIG. 9 is an explanation of a product defect when trying to avoid the disadvantages of the conventional method. FIG. 10 is a diagram illustrating the necessity of a thrust collar with respect to the effective roll length and the strength thereof. 1 ... Square steel plate, 2 ... Web 3 ... BD mill, 4 ... Rough mill 5 ... Intermediate mill, 6 ... Finishing mill 7,8 ... Corner of web 9,10 ... K- 3 Upper roll 11… Flange, 12… Claw 13,14… Inlet guide 15,16… Guide roller 17… Corner wear 18… Stretching inside the web 19,20… Balance 21, 22… Upper and lower rolls of K-5 23… Thrust collar, a… Rough molding b… Intermediate molding, c… Finish molding B …… Web width of hole type f… From flange to claw Width W: Hole width l: Web center line length h: Web corrugation height ΔB: Web width expansion amount between hole dies e: Contact point between upper roll and steel g: Lower roll effective barrel length l ₁ of the gap L ...... roll contact point i ...... on the roll and a steel flange portion of the steel, l ₂ ...... thrust collar thickness

Claims (1)

(57) [Claims] 1. A web formed in a corrugated shape from a rough shaping die to immediately before a final shaping die when rolling shaping from a rectangular cross-section billet by a double roll rolling mill. In the rolling method of bending the web and forming the web in a straight line, the center line lengths of the webs between the respective dies are made substantially the same, and one to four dies until the final finishing die are used. A method for rolling a U-shaped sheet pile, comprising sequentially expanding and rolling a web width of a maximum of 20 mm per die.