JPH07323301A - Hot rolling equipment for steel sheet pile - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a hot rolling apparatus that can achieve high productivity without defective shape of steel sheet pile. [Structure] Two hole-type rolling stands (S1, S2), which perform both rough rolling and finish rolling, are provided close to each other, and an open hole type (, and) is pressed down in the thickness direction of the joint portion of the steel sheet pile.
And a closed hole type (and) which is continuously pressed down to determine the size of the tip of the rolled material M, which opposes to move the rolled material M straight to the two separate stands (and, and and, respectively). A hot rolling apparatus for steel sheet piles that are provided so as to face each other on a straight line. [Effect] Since the rolled material goes straight from the open hole type to the closed hole type and is bitten, the steel sheet pile joint portion in the closed hole type does not collapse and the yield due to defective shape is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling apparatus for steel sheet piles, which is placed in the ground as an earth retaining material in civil engineering work.

[0002]

2. Description of the Related Art FIG. 6 is a view showing an example of a cross section of a steel sheet pile, (a) showing a cross-sectional shape, and (b) showing a connected state. Reference numeral 1 is a web, 2 is a flange, and 3 is a joint portion. The steel sheet pile is composed of a web 1 and a flange 2 having a joint portion 3 as shown in Fig. 1 (a), and when the steel sheet pile is placed in the ground, the direction of the flange 2 is changed for each one as shown in (b). On the contrary, the claw 4 of the joint portion 3 is replaced by the space portion 5 of the mating joint portion.
Insert it in and do. For this reason, if the cross-sectional shape of the joint is not accurately finished, it may not be possible to place the joint.

FIG. 2 is a view showing a conventional hot rolling line for manufacturing a steel sheet pile. B is a breakdown mill, R is a rough rolling mill, F is a finish rolling mill, H is a heating furnace, M is a rolled material,
Are hole types provided on the rolls of the rolling mill. The steel sheet pile is formed by continuously casting bloom (rolled material M) into a hole shape of a breakdown mill B, a rough rolling mill R and a finish rolling mill F.
Then, each is reciprocally rolled and finished into a sectional shape as shown in FIG.

FIG. 3 is a view showing an example of a hole type row arranged on rolls from a breakdown mill to a finish rolling mill. In general, the break mill is provided with holes and, the roughing mill is provided with holes and the finishing mill is provided with holes and. The rolled material M discharged from the heating furnace H is rolled in 3 passes in each hole type of the breakdown mill B and in each of the hole types (from to) in the rough rolling mill R and the finish rolling machine F. Each pass is rolled and finished into a steel sheet pile.

FIG. 4 is a diagram showing an example of the types of hole type, in which (a) is a hole type (hereinafter referred to as an open hole type) for pressing down a joint portion of a steel sheet pile in the thickness direction, (b) ) Is a diagram showing a hole type (hereinafter, referred to as a closed hole type) that is pressed down in its length direction. In the open hole type, as shown in (a) of the same figure, the tip end of the rolled material forming the claws of the joint portion is extended along the hole type to perform reduction in the thickness direction. Further, the closed hole type has a function of suppressing the extension of the tip of the rolled material forming the claws of the joint portion and determining the dimension of the tip. As shown in FIG. 3, the hole dies having different sectional shapes having different functions are alternately arranged in each rolling mill.

[0006]

In the conventional reciprocating rolling method, as shown in FIG. 2, three rolling mills (B, R, F) roll back and forth rolling material by each rolling mill. When a plurality of rolled materials are rolled simultaneously in each mill, the rolled materials may collide on the exit side of the die and the exit side of the die. In order to avoid this, the rolled material was bit into the die of the finish rolling mill F, and then was bit into the die of the rough rolling mill R, so that the production efficiency was lowered. Further, a method of increasing the interval between the rolling mills and a method of continuously rolling in a single pass using a large number of rolling mills can be considered, but both require a long installation site and capital investment. Further, in the product as well, there is a problem that a defective shape (a defective joint shape) occurs at the front end and the rear end of the rolled material, which is cut off by about 3 m and the yield is reduced.

An object of the present invention is to use a reciprocating rolling mill,
An object of the present invention is to provide a hot rolling apparatus in which a defective shape of a joint portion of a steel sheet pile is reduced and rolling materials do not collide between rolling mills.

[0008]

As a result of various investigations on the cause of the defective shape of the steel sheet pile joint, the present inventor has obtained the following findings.

FIG. 5 is a diagram showing a state of reciprocal rolling with a conventional rough rolling mill R, (a) is a diagram showing a flow of a rolled material M, and (b) is a diagram when it is bitten into a hole shape. It is a figure which shows the collapse of the front-end | tip part of a joint part. When reciprocating rolling with a conventional rough rolling machine,
When the rolled material moves from the open hole type to the closed hole type as shown in Fig. 1 (a), it is bitten into the closed hole type, and the tip of the joint part of the steel sheet pile enters the closed hole type. It gets harder. As a result, the rolled material is
As shown on the left side, it falls down and does not form a normal joint part.

Based on this finding, it was confirmed that the tip of the joint portion of the steel sheet pile can be smoothly engaged with the hole type by changing the arrangement of the hole type of the rolling mill, and the present invention was completed. .

The gist of the present invention resides in the following hot rolling apparatus for steel sheet piles as shown in FIG.

An apparatus for producing a steel sheet pile by hot rolling, in which two hole-type rolling stands (S1, S2), which also serve as a rough rolling machine and a finishing rolling machine, are provided in close proximity to each other, and a joint portion of the steel sheet pile is provided. Open-hole type (and) that reduces in the thickness direction of
And the closed-hole type (and), which is subsequently pressed to determine the size of the tip of the rolled type, face each other (and, and and, respectively) so that the rolled material goes straight to the two separate stands. Opposite on a straight line)
A hot rolling device for steel sheet piles.

[0013]

FIG. 1 is a view showing a hot rolling apparatus for steel sheet piles according to the present invention. B is a breakdown mill, S1 is a first stand, and S2 is a second stand.

Instead of the two rolling mills (R and F in FIG. 2) which are conventionally provided to share the roles of rough rolling and finish rolling, the device of the present invention has a first stand 1 and a second stand. 2 are arranged in close proximity to each other, and the hole type and the hole type are provided so as to face two stands, respectively. In the rolling by this apparatus, the rolled material M is made to go straight in the skewer shape between the first stand and the second stand, and rolling from the hole shape is performed by a total of three reciprocal rollings. Here, “proximity” means that there is no table roll between the two stands, and the stands are continuously arranged.

An open hole type, a closed hole type and an open hole type are arranged in the first stand S1, and a closed hole type, an open hole type and a closed hole type are arranged in the second stand S2. Also, each hole type of the first stand and each hole type of the second stand (and, and and)
Are arranged so that the rolled material can go straight.

In this case, the shapes of the hole type and the hole type are shown in FIG.
It is relatively similar as shown in (3), and it is the difference only in the shape () that can press down the tip of the joint portion or not (), and the biting property is improved, and troubles between stands are less likely to occur. This relationship is the same for the second-pass hole type. As a result, the rolled material can be bitten straight into the closed hole type (particularly),
In particular, the tip of the joint portion of the steel sheet pile in the hole type does not fall.

In the apparatus of the present invention, the two stands S1 and S2 are arranged in close proximity to each other, and the rolled material passes through the two hole dies in a skewer shape and is rolled in one pass. The number of passes is the same, but the number of round trips of the material is halved. This also reduces the total travel distance of the material and reduces the temperature drop. Further, there is no fear of collision of rolled material, and the production efficiency is greatly improved.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples in which the present invention is applied to a type III steel sheet pile manufacturing apparatus.

The first stand S1 and the second stand shown in FIG.
Using a hot rolling line with a distance between S2 and the stand axis of 5 m, and using a continuous casting bloom with a thickness of 200 mm and a width of 480 mm as the rolled material M, after heating to 1250 ° C in a heating furnace H, rolling I went to

The heated rolled material M is reciprocally rolled in four passes in the closed hole type of the breakdown mill B, three passes in the open hole type and two passes in the closed hole type. 40mm web thickness
A steel sheet pile rough shaped material was obtained.

The web thickness of the rolled material is 40 mm to 30 mm for the hole type in the first pass of the first stand and the second stand.
In addition, the hole type is pressed down to 26 mm. Then, in the second pass, the web thickness is reduced from 26 mm to 16 mm for the hole type and 12 mm for the hole type.

In the third pass, the claw portion of the joint portion of the hole type is slightly bent inward (flange side), and the hole type is bent further inward by about 40 ° (flange side) to form an inclined portion of the claw forming the space portion. With the angle of about 50 °, the product was finished as a steel sheet pile type III. In the third pass, the web thickness was reduced from 12 mm to 11 mm or 10 mm.

When the above apparatus of the present invention was used, the biting pitch of the rolled material into the hole die of the first stand was about 150 seconds, and the rolling capacity was 150 T / hr. In addition, the steel sheet pile joints did not collapse, and the rolling yield was improved by 0.4% over the conventional method.

(Comparative Example) The same test as in the example was conducted on a conventional rolling line in which the distance between the rough rolling mill and the finishing rolling mill shown in FIG. 2 was 80 m. In addition, after confirming that the preceding material bit into the hole die, the next material was bited into the hole die. Therefore, the biting pitch of the rolled material into the hole shape of the rough rolling mill R is about 220 seconds, and the rolling capacity is 1
It was 20 T / hr. The defective product due to the collapse of the joint part of the steel sheet pile was 3 m at the top and bottom of the rolled material 120 m, and the rolling loss was 2.5%.

[0025]

The hot rolling apparatus for steel sheet piles according to the present invention is provided with two hole-type roll stands in close proximity to each other so that the rolled material moves straight from the open-hole type to the closed-hole type and bites into the hole. Since the molds are arranged facing each other in a skewered shape, not only the rolling line is shortened and the installation cost is low, but also the steel sheet pile joint part in the closed hole type does not collapse and the yield due to defective shape is improved. It Further, since there is no fear of collision of the material during rolling, the production efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a view showing a hot rolling apparatus of the present invention for manufacturing a steel sheet pile.

FIG. 2 is a diagram showing a conventional hot rolling apparatus for manufacturing a steel sheet pile.

FIG. 3 is a view showing a hole type row when hot rolling a steel sheet pile.

4A and 4B are diagrams showing types of hole types when hot rolling a steel sheet pile, wherein FIG. 4A is a view showing an open hole type, and FIG. 4B is a view showing a closed hole type.

FIG. 5 is a diagram showing a rolling situation in a conventional rough rolling mill, (a) is a diagram showing a material rolling flow, and (b) is a diagram showing material collapse in a closed hole type.

FIG. 6 is a diagram showing an example of a cross section of a steel sheet pile and a state where the steel sheet pile is connected.

[Explanation of symbols]

S1. First stand S2. Second stand B. Breakdown Mill R. Rough rolling mill F. Finishing mill H. Heating furnace M. Rolled material ~. Hole type 1. Web 2. Flange 3. Joint part 4. Nails 5. Space section

Claims (1)

[Claims] 1. An apparatus for manufacturing a steel sheet pile by hot rolling, in which two hole-type rolling stands, which also perform rough rolling and finish rolling, are provided in close proximity to each other in the thickness direction of a joint portion of the steel sheet pile. The hole die for rolling down and the hole die for rolling down so as to subsequently determine the size of the tip of the hole die are provided on the two separate stands so as to face each other so that the rolled material goes straight. Steel sheet pile hot rolling equipment.