JPH0724502A - Flying joining method for slab in continuous hot rolling - Google Patents

Abstract

PURPOSE:To mutually join slabs in running without using such a looper as the slab is bent and elavated upward and also without receiving adverse effect due to excessive tension. CONSTITUTION:After the rear end part of a preceding slab 1 and the tip part of the succeeding slab 2 are joined in running at the time of continuously executing hot finish rolling by feeding to a finishing mill group 6, the slab is bent so as to be along table rollers by lowering the transporting table rollers 5 in feeding process after the slabs are joined until they reach the inlet side of the finishing mill group and the generation of excessive tension from the region for joining the slab to the inlet side of the finishing mill group is avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to join steel strips such as sheet bars, slabs, billets or blooms between strips during continuous rolling of several or dozens of strips. It concerns a suitable method.

[0002]

2. Description of the Related Art Conventionally, in a hot rolling line for billets, the billets to be rolled are individually heated, rough-rolled and finish-rolled to finish a hot-rolled sheet having a desired thickness. Such a rolling method is unavoidable in finishing rolling because of line stoppage due to defective biting of rolling material or defective trailing edge, and a significant reduction in yield due to defective shape of the leading and trailing edges of the rolling material. was there.

For this reason, recently, a rolling system has been adopted in which the rear end portion and the front end portion of the steel pieces to be rolled are joined prior to the finish rolling and continuously fed to the hot rolling line for rolling. It started to come.

Here, in order to join the trailing end of the preceding steel piece and the leading end of the trailing steel piece, a joining device that joins the steel pieces between runs using a joining device that can follow the movement of the steel pieces. Method
(JP-A-63-104706 and JP-A-57-199579)
A looper system in which a looper is installed in the conveying path for steel or steel pieces, and the steel pieces are temporarily stopped in the joining device for joining processing.
(JP-A-59-209405 and JP-A-63-93408) are applied, but such a joining method has the following problems.

That is, in the running-to-run joining method, it is necessary to synchronize the conveying speed of the preceding billet and the moving speed of the joining device, which are synchronized with the entry speed of the finishing rolling mill group. In addition to synchronizing with the former two of them, a fixed distance (0-20
(mm) is required to be positioned, but the speed of the steel slab is easily measured because it is measured with a measuring roll or plate speed meter, which makes accurate positioning difficult. If there is a difference in the moving speed between the strip and the trailing strip, tension is generated in the strip, and if this is too large and the strips are not yet in the joined state, the end faces of the strips are brought into contact with each other. Since it is difficult to do so, the ability of the device (ability to press the steel pieces against each other) assuming such a situation
Was required to be increased more than necessary in advance, and further, when excessive tension was generated after joining the steel pieces, the steel pieces could be fractured from the joint.

On the other hand, a looper is provided in the conveying path of the steel slab,
In the method of carrying out the joining process by stopping the transportation of the steel pieces in the joining apparatus, it is not necessary to synchronize the joining apparatus and the steel pieces, and therefore, there is no problem as described above. However, since a looper for bending the steel slab and lifting it upward is separately required, there is an unavoidable disadvantage in that the equipment cost increases.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to propose a new joining method capable of solving the above-mentioned problems that occur when joining steel pieces to each other.

[0008]

According to the present invention, after joining the trailing end of the preceding steel slab and the leading end of the trailing slab in the run, it is fed to the finishing rolling mill group and continuously heated. In the inter-finish rolling, the transport table roller is lowered in the feeding process from joining the steel pieces to reaching the entry side of the finishing rolling mill group to bend the steel pieces along the table rollers, It is a running joining method for steel strips in continuous hot rolling, which is characterized by preventing the generation of excessive tension from the joining area of the steel strips to the entry side of the finishing rolling mill group.

FIG. 1 shows a schematic diagram of equipment suitable for carrying out the present invention. In the figure, 1 is a leading billet, 2 is a trailing billet,
Reference numeral 3 denotes a steel slab joining device. The joining device 3 is movable in accordance with the conveyance of the steel slabs 1 and 2, and inside thereof, the rear end portion of the preceding steel slab 1 and the trailing steel slab 2 are provided. The tip portions of the steel sheets are fixed by clamps, and the steel pieces are joined together by pressing after heating with the end surfaces in contact with each other or with a predetermined gap maintained.

Reference numeral 4 is a fixed table roller, and 5 is a table roller movable up and down. This vertically movable table roller 5 moves up and down in accordance with the movement of the joining device 3 so as to avoid it, and in the area from the exit side of the joining device 3 to the entry side of the finishing rolling mill group 6, The pieces are bent (the region where the steel pieces are bent may be moved toward the finishing rolling mill group 6 at any time in accordance with the movement of the joining device 6). It is possible to avoid the generation of excessive tension between the sides.

Although the control mechanism of the table roller 5 is not shown in the drawing, the table roller in the region where the steel slab is bent is an electric type having a load cell, and the level is set so that the load becomes a predetermined value for each roller. Control is performed, or hydraulic control is performed so that each roller is pushed up by a predetermined pressure.

[0012]

In the present invention, when the leading steel piece 1 and the trailing steel piece are joined during running, the steel pieces are bent between the joining device 3 and the finishing rolling mill group 6, so that the joining device Since the difference in speed between the steel piece 3 and the steel pieces 1 and 2 can be absorbed here, excessive tension does not occur and it is difficult to join the steel pieces or the steel pieces after joining Will not break apart.

In FIG. 1 above, the case where the steel slab is bent by its own weight is taken as an example, but for a material with a large plate thickness, the steel slab is pressed downward by at least one roll from above. May be.

In the present invention, even if there is a speed difference between the joining device 3 and the steel pieces 1 and 2, the steel piece is bent (hereinafter, this deflection is referred to as a loop). Although it is possible to absorb the deviation, it can be said that when a larger speed fluctuation occurs in a state where the loop amount of the steel slab is reduced, there is no adverse effect due to the generation of excessive tension. Therefore, the tension or loop amount of the billet is detected at any time,
It is preferable to control the speed of the joining device 3 based on the detection result.

As shown in FIG. 2, the steel strip loop is a plain steel sheet bar having a plate width of 900 mm, a thickness of 30 mm and a temperature of 1000 ° C., and an area of about 5 m in the longitudinal direction of the plate. Across
It should be lowered about 100 mm. The loop of the billet is also necessary to alleviate the speed fluctuation (the mass flow is disturbed because the speed of the bogie and the trailing material does not follow even if the speed on the rolling mill entrance side suddenly changes). Can be said to be sufficient in view of the responsiveness of a normal control device.

[0016]

[Example] Using the equipment as shown in FIG.
When a sheet bar (steel type: ordinary steel) with a plate width of 1000 mm and a plate width of 1000 mm is joined on the entry side of the finishing rolling mill group during run-time joining at a material speed of 1 m / s on the finishing entry side, a loop area of 5 m, loop height The thickness was 500 mm, and the variation of the tension of the steel slab at that time was investigated. As a result, it was confirmed that the tension of the steel slab was maintained at a constant value of 5 TON regardless of the fluctuation of the moving speed of the welding device and the transport speed of the steel slab, and the steel slab could be welded under stable conditions. When the carriage speed of the carriage and finishing mill speed table is controlled based on the loop height (loop amount),
The tension was almost zero. Also, 30 T without loop
It turned on and the joint broke.

[0017]

According to the present invention, the steel pieces are joined to each other during a run without using a looper for bending the steel pieces and lifting them upward, and without being adversely affected by excessive tension. it can.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of equipment suitable for carrying out the present invention.

FIG. 2 is a diagram showing a bending state of a steel slab.

[Explanation of symbols]

 1 Leading steel slab 2 Trailing steel slab 3 Joining device 4 Fixed guide roller 5 Elevating guide roller 6 Finish rolling mill group

Front page continued (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside Kawasaki Steel Co., Ltd. (72) Inventor Junzo Nitta 1 Kawasaki-cho, Chuo-ku, Chiba Chiba Steel Co., Ltd. Chiba Steel Works (72) Inventor Takesada Tosada 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Norio Takashima, Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Works Co., Ltd. Chiba Works (72) Inventor Kazunori Nagai 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Kunio Miyamoto 4-chome, Kannon Shinmachi, Hiroshima City, Hiroshima Prefecture 6-22 No. 22 Mitsubishi Heavy Industries Ltd. Hiroshima Works

Claims (1)

[Claims] 1. A steel slab for joining a trailing end portion of a preceding steel slab and a leading end portion of a trailing steel slab in a running state and then feeding the slab to a finishing rolling mill group for continuous hot finish rolling. In the feeding process from the joining to the entry side of the finishing rolling mill group, the transport table roller is lowered to bend the steel slab along the table roller and finish rolling from the joining area of the steel slab. A running joining method for steel slabs in continuous hot rolling, characterized in that excessive tension is prevented from occurring until reaching the entry side of a group of machines.