JPH08117801A - Rolling method for asymmetric U-shaped steel sheet pile - Google Patents

Abstract

PURPOSE: To stably form an asymmetrical U-shaped sheet pile by first screwing down a material with the flange parts of a groove and inversely bending and forming right and left joint parts with the same groove. CONSTITUTION: At the time of executing finish groove rolling, first, the lower parts of the symmetrical right and left flange parts 13 of a material 12 to be rolled are screwed down with the flange parts of finishing grooves which are carved on groove rolls 11. Thus, both right and left sides of the material 12 to be rolled are restrained and it is prevented for the material to shift right and left between the groove rolls 11. Next, by first bringing the tip of one joint part 14 into contact with the groove rolls 11, the bending/forming of the joint part 14 are started and, further, by bringing the tip of the other joint part 15 into contact with the groove rolls 11, the bending/forming of the joint part 15 are executed in the inverse direction to the upper and lower parts of the joint part 14. In this way, the right and left joints 14, 15 having reference opening degree and asymmetrical shape are simultaneously and stably formed with a single groove in one pass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for steel sheet piles used in civil engineering and construction work, and more particularly to hot rolling a joint portion of an asymmetric U-shaped steel sheet pile having joint portions having different left and right shapes. The present invention relates to a method of finish rolling.

[0002]

2. Description of the Related Art Conventionally, for finishing a U-shaped steel sheet pile (hereinafter referred to as a symmetrical U-shaped steel sheet pile) 71 having a symmetrical symmetrical joint portion shape as shown in FIG. The material to be rolled 5 using the hole-shaped roll 51 in which the hole shape of
A method of finishing the left and right joint portions (claw portions) 54 and 55 of 3 in one pass, and a method of performing finish forming with a roller guide arranged in the latter stage of the finishing hole type instead of finishing with the hole type roll are performed. In steel sheet pile rolling, as described in detail below, it is common to perform bending forming of the joint portion in the final pass, and "finishing (forming)" here means "bending of the joint portion ( Molding) ”.

Here, to give an example of a typical method for manufacturing the symmetrical U-shaped steel sheet pile 71, there are the following steps (1) to (3) described later in detail in the examples.

First, a raw steel slab or a cast slab is heated in a heating furnace 81, and then a revolving mill K-10 to K-7 engraved on a horizontal roll of a rough rolling mill 82 is used to perform reversible rolling a plurality of times.
Mold into a thick semi-finished product having a cross-sectional shape of -7.

Next, the thick semi-finished product is an intermediate rolling mill 83.
1 for each hole type K-6 to K-4 engraved on the horizontal roll of
By pass rolling or multiple times of reversible rolling, the thickness of the web-corresponding portion and the flange-corresponding portion is reduced and stretched to form a semi-finished U-shaped steel sheet pile having a hole K-4 cross section.

Then, the semi-finished U-shaped steel sheet pile is subjected to one-pass rolling or multiple reversible rollings for each hole type by a finish rolling machine 84 having a horizontal roll in which roll hole types K-3 to K-1 are engraved. After performing the finish forming of the web and the flange and forming the joint portion (claw portion) by the roll hole type K-2 of the finish rolling machine 84, the roll hole type K-1 of the finish rolling machine 84 is performed. Thus, the joint portion is bent and formed.

In addition, the hole type K-10 to K formed on each horizontal roll used for manufacturing the above-mentioned symmetrical U-shaped steel sheet pile 71.
All -1 are symmetrical.

However, in recent years, for the purpose of maximizing the use of land in middle- and low-rise building construction in urban areas, the aim is to reduce the space between adjacent land boundaries, which was necessary during construction, and to make automatic placement by non-rotating placement. In the case of a U-shaped steel sheet pile (hereinafter referred to as asymmetrical U-shaped steel sheet pile) 21 having different joint shapes on the left and right, such as the new steel sheet pile of FIG. 2 developed in FIG. 2, (a) to (c) of FIG. As shown in the order of forming, one of the joint portions 33 of the material 32 to be rolled is engraved on the hole roll 31 to form a roll hole die 3
It is general to finish by 5 and then perform reversible rolling using different roll hole dies 36 engraved in the same hole roll 31 to finish the other joint portion 34.

By the way, in this case, since two finishing hole dies to be engraved on one roll are required, a normal symmetrical U
Since the number of roll hole dies is increased by one as compared with the case of finish rolling of the shaped steel sheet pile, this is a big problem when the roll barrel length is limited. Therefore, as shown in FIG. 4, one joint portion 45 of the material 44 to be rolled is finished with a hole die engraved on the hole roll 42 of the finish rolling mill 41, and the other joint portion 46 is provided at the latter stage of the finish rolling mill 41. A method has been proposed in which the roller guides 43 are arranged to apply a horizontal reduction to finish. However, this method has a problem that the shape stability of the joint portion 46 is lacking.

[0010]

An object of the present invention is to form a joint portion of an asymmetric U-shaped steel sheet pile by using a hole-shaped roll having the same number of hole shapes as the case of a normal symmetrical U-shaped steel sheet pile. It is to provide a hot finish rolling method that makes it possible.

[0011]

Means for Solving the Problems The present inventor has obtained the following findings as a result of repeated studies for solving the above problems.

The conventional symmetrical U-shaped steel sheet pile is shown in FIG.
As shown in (a), the left and right joints 54 and 55 of the material 53 to be rolled are finished by one-pass rolling using a left-right symmetric single roll hole die engraved on the hole roll 51. In this case, since the shape is bilaterally symmetric, the starting point of rolling by the hole-shaped roll 51 for shaping the joint shape is also bilaterally symmetrical. Therefore, the material to be rolled 53 is rolled while being uniformly restrained in the left-right direction by the hole-shaped roll 51, It is possible to perform bending while stabilizing the opening of the joint portions 54 and 55.

In the case of an asymmetrical U-shaped steel sheet pile having different joint shapes on the left and right sides, as shown in FIG. 5B, the material 5 to be rolled by the hole-shaped roll 52 for shaping the joint portions 56 and 57 is formed.
Since the rolling start point and the direction of the rolling force of No. 3 are different on the left and right sides, the restraining force becomes non-uniform, which causes lateral displacement and twisting at the time of biting. Therefore, as shown in FIG. If it comes into contact with the grooved roll 52 first, the material 53 to be rolled will be displaced to the right. Therefore, the bending of the left and right joints 56 and 57 is not sufficiently performed, and the opening of the joint becomes larger than the reference.

Even in the case of an asymmetrical U-shaped steel sheet pile, as shown in FIG. 5 (b), the flange portion 58 is bilaterally symmetrical. If the lower portion of the portion 58 is pressed down by the flange portion of the hole-type roll 52, it is possible to prevent the material 53 to be rolled from being laterally displaced or twisted at the time of biting in the roll-hole type.

Subsequent to the above processing, one end of the joint portion is brought into contact with the hole type roll 52 first, and later the other end of the joint portion is brought into contact with the hole type roll 52. It is possible to simultaneously stably form the left and right asymmetric joint portions 56 and 57 having a reference opening degree by using only the above.

The gist of the present invention based on the above findings is a finish rolling method for a joint portion of an asymmetric U-shaped steel sheet pile shown below.

A method of finish rolling in a single pass by using a single hole die in which right and left joints having different shapes are engraved in a roll, wherein the lower end of the flange of the material to be rolled is engraved in the roll A hot rolling method for an asymmetric U-shaped steel sheet pile, characterized in that the flange portion is first rolled down, and then the left and right joint portions having the same hole shape and different shapes are respectively bent and bent in the opposite directions.

[0018]

The present invention will be described below together with its function and effect.

When finishing rolling an asymmetric U-shaped steel sheet pile with upper and lower rolls, as in the case of finishing rolling a normal symmetrical U-shaped steel sheet pile, when the tip end of the joint portion is first brought into contact with the hole-shaped roll, for example, as shown in FIG. In the case of b), the tip of one side 57 of the asymmetrical joint is in a state of being disengaged from the hole roll 52, and therefore, the person who is not in contact with the hole roll 52, in other words, receives the restraining force. Since the rolled material 53 is displaced to the side of the joint portion 57 which is not present, the bending of the finish is not sufficiently performed, and the opening amounts of the joint portions 56 and 57 are both larger than the reference, so that an asymmetric U-shaped steel sheet pile having a desired shape is obtained. I can't.

On the other hand, as shown in FIG. 1 (a), when performing finish-rolling, first, the lower end of the symmetrical flange portion 13 of the material 12 to be rolled is carved into the finish roll 11. The material to be rolled 12
Since both of the left and right sides are restrained, the material 12 to be rolled can be prevented from shifting to the left and right in the hole roll 11. Then, as shown in FIG. 1B, one joint portion 1
The tip of 4 is brought into contact with the hole-shaped roll 11 first, and the joint portion 1
Bending of No. 4 was started, and after that, as shown in Fig. 1 (c).
As shown in FIG.
The joint part 1 in the direction opposite to that of the joint part 14
If you perform bending of No. 5, it is a single hole type and 1 pass,
Asymmetrical left and right joints 14 and 1 having a standard opening
5 can be stably molded at the same time.

In order to carry out the above-mentioned finish-rolling, the finish-rolling is performed so that the lower part of the flange of the material to be rolled first comes into contact with the finish-rolling when biting into the roll.
The width of the flange opening of the previous hole type may be made smaller than that of the finished hole type.

By the way, in the above manufacturing method, the lower part of the symmetrical flange portion 13 of the material 12 to be rolled is firstly pressed down because the asymmetric U-shaped steel sheet pile is not symmetrical except the flange portion 13 and the material to be rolled is not symmetrical. It is extremely difficult to constrain 12 simultaneously at the left and right, and even in the case of the symmetrically symmetrical flange portion 13, if the parts other than the lower portion are constrained at the same time at the left and right sides, the asymmetrical joint portions 14 and 15 will have a desired shape. This is because there will be a large deviation.

[0023]

EXAMPLE A rolling apparatus train having the structure shown in FIG.
2. A symmetrical U-shaped steel sheet pile and an asymmetrical U-shaped steel sheet pile were manufactured using the intermediate rolling mill 83 and the finishing rolling mill 84). The arrow below the device row in FIG. 8 indicates the flow path of the material to be rolled passing through each of the cavities shown by black circles.

[Symmetrical U-shaped steel sheet pile (size: 600 mm x 200 m
m, web thickness: 12 mm)] Rolled material thickness 2
Heating furnace for continuous casting bloom of 50 mm x 700 mm width
After being heated to 1250 ° C. in No. 1, the web thickness was reversibly rolled in 9 passes using a roll having four hole types K-10 to K-7 shown in Table 1 in a double type rough rolling machine 82. 38m
Roughly rolled into a thick semi-finished product of m.

Next, the web was thinned and stretched to a web thickness of 20 mm by three-pass reversible rolling with an intermediate rolling mill 83 using rolls having three hole types K-6 to K-4, and further, K Using a roll having three hole shapes from -3 to K-1, the finish rolling machine 84 finished the desired product shape by the three-pass reversible rolling. Table 1 shows the pass schedule in this case.

As a matter of course, a product having a sufficiently satisfactory shape as a symmetrical U-shaped steel sheet pile was obtained.

[Asymmetric U-shaped steel sheet pile (size: 600 mm x 20
0 mm, web thickness: 12 mm)] As in the case of the symmetrical U-shaped steel sheet pile, hot rolling was performed according to the pass schedule shown in Table 2. That is, the thickness of rolled material is 250 mm
× 12 continuous heating bloom of 700mm width in heating furnace 81
After heating to 50 ° C., the rough rolling machine 82 is operated from K-20 to K-
The roll was reversibly rolled in 9 passes using a roll having four holes of 17 and roughly rolled into a thick semi-finished product having a web thickness of 38 mm.

Then, a three-pass reversible intermediate rolling is carried out by an intermediate rolling mill 83 having a roll in which three hole types K-16 to K-14 are engraved to reduce and stretch the web to a thickness of 20 mm. , K-13 to K-11, using a roll having three hole types, a rolling mill 84
Finished to the desired product shape by pass reversible rolling.

Here, the final hole type K-11 corresponds to the finishing hole type, and when rolling the material to be rolled by the upper and lower rolls as shown in FIG. 1, first, the lower part of the flange is restrained (see FIG. )) Next, the bending of the left joint was started ((b) in the same figure), and finally, the bending of the right joint was performed in the opposite direction to the bending of the left joint. ((C) of the same figure).

As described above, the finish rolling of the asymmetrical U-shaped steel sheet pile is performed before the finish hole die so that the lower portion of the flange of the rolled material comes into contact with the finish hole die first when biting into the roll. Regarding the hole shape, the width of the flange opening was made smaller than that of the finished hole shape.

FIG. 6 shows the shape of the product manufactured by the above method. The product shape is sufficiently satisfactory as an asymmetric U-shaped steel sheet pile, and it is clear that the method of the present invention can stably form the left and right joint portions of the asymmetrical shape having the reference opening degree in a single hole shape and in one pass. Is. That is, according to the present invention, it can be seen that it is possible to form the joint portion of the asymmetric U-shaped steel sheet pile by using the same number of hole-shaped rolls as the number of engraved hole types as in the case of a normal symmetrical U-shaped steel sheet pile.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

As described above, according to the method of the present invention, an asymmetrical U-shaped steel sheet pile can be stably formed with the same hole-shaped arrangement as that of a normal symmetrical U-shaped steel sheet pile, so that the industrial effect is extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view of a hole portion showing a rolling situation according to the method of the present invention. (A) is a restraint condition of the flange portion, (b) is a condition of starting bending forming of the left joint part, and (c) is a condition of starting bending forming of the right joint part.

FIG. 2 is a view showing a cross-sectional shape of an asymmetric U-shaped steel sheet pile.

FIG. 3 is a cross-sectional view of a hole portion showing a method for bending a joint portion of an asymmetric U-shaped steel sheet pile. Molding proceeds in the order of (a), (b), and (c).

FIG. 4 is a schematic view showing a conventional method of bending and forming a joint portion by a roller guide. (A) shows the positional relationship between the roller guide and the finish rolling mill, and (b) shows the state of forming by the roller guide.

FIG. 5 is a cross-sectional view showing a state of contact and movement of a material to be rolled with a roll in bending and rolling of a joint portion. (A) is a case of a symmetrical U-shaped steel sheet pile, (b) is a case of an asymmetrical U-shaped steel sheet pile.

FIG. 6 is a cross-sectional view showing a product shape of an asymmetrical U-shaped steel sheet pile formed in the example.

FIG. 7 is a view showing a cross-sectional shape of a symmetrical U-shaped steel sheet pile.

FIG. 8 is a schematic diagram showing an arrangement of heating furnaces and rolling devices that manufactured products in Examples and a rolling pass flow.

[Explanation of symbols]

21: Asymmetrical U-shaped steel sheet pile, 71: Symmetrical U-shaped steel sheet pile, 1
1, 31, 42, 51, 52: Porous rolls, 12, 3
2, 44, 53: material to be rolled, 13, 58: flange portion, 14, 15, 33, 34, 45, 46, 54, 5
5, 56, 57: Joint part, 35, 36: Roll hole type, 4
1: Finishing rolling mill, 43: Roller guide, 81: Heating furnace, 82: Rough rolling mill, 83: Intermediate rolling mill, 84: Finishing rolling mill

Claims (1)

[Claims] 1. A method of finish rolling in a single pass using a single hole die in which right and left joints having different shapes are engraved in a roll, wherein the lower end of the flange of the material to be rolled is engraved in the roll. A hot rolling method for an asymmetric U-shaped steel sheet pile, characterized in that the flange portion of the die is first rolled and then the left and right joint portions of the same hole die having different shapes are bent in opposite directions.