JPH06170411A - Continuous hot rolling equipment for billet - Google Patents

Abstract

PURPOSE:To reduce a curl and to avoid rapture and separation of a steel plate by arranging a leveler provided with a guide to introduce the tip of a billet between rollers at least on one of the inlet side and the outlet side of a cutting device. CONSTITUTION:The guide 3a to introduce the tip of the billet is provided on the inlet side of the leveler 3 made of a combination of plural rolls and the curl left in the recoiled billet is reduced by passing this guide. A joining device 5 joins the rear end part of the preceeding, recoiled and cut billet and the tip part of the succeeding, recoiled and cut billet as they are brought face to face with each other, heated and pressed to each other. In this way, when the tip parts of the billets are butted, the plates scarcely slip, consequently, the rapture and separation of the plate on rolling can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to continuous hot rolling of a steel slab suitable for continuously hot rolling several to several tens of steel slabs such as a sheet bar, slab, billet or bloom. Regarding equipment, it is possible to reduce the plate slippage at the joint due to deformation (rolling) of the steel slab, which is a problem when butt-joining the rear end of the preceding slab and the leading end of the subsequent slab, and stabilize It is intended to realize the hot rolling.

[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 and width. However, in such a rolling method, it is difficult to stop the line due to defective biting of the rolled material in finish rolling, and it is difficult to improve productivity. There was also a significant disadvantage in yield reduction due to defective shape.

For this reason, in recent years, 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 finish rolling, and this is continuously fed to a hot rolling line for rolling. The equipment for that is, for example, a rough rolling machine, a coil box, a shear, a fixed welding machine, a sheet bar storage device, and a finishing rolling machine, which are arranged sequentially along the line. A rolling arrangement row is known (see Japanese Patent Application Laid-Open No. 58-112601).

In the equipment disclosed in the above publication, sheet bars that have undergone rough rolling are successively wound into coils, and the sheet bar coils are unwound according to the processing conditions in the finish rolling step. Join the rear end of the rewound sheet bar and the front end of the sheet bar that is subsequently rewound, and then feed it to the finishing rolling mill to finish the strip to the target thickness and width. According to this, the productivity could be remarkably improved as compared with the conventional method in which the treatment was performed one by one. However,
In such equipment, there is an unavoidable residual winding curl when the sheet bar is unwound, and there is a disadvantage that when the front end portion and the rear end portion of the sheet bar are butted, a plate shift occurs and a good joined state cannot be obtained. Such plate deviation causes breakage and separation of the plate in finish rolling and causes a significant hindrance to the rolling work, and therefore its solution has been demanded.

In Japanese Patent Laid-Open Nos. 4-89109 and 4-89110, the trailing end portion of the preceding steel piece and the leading end portion of the following steel piece are brought into contact with each other in the thickness direction of the steel piece in that region. A joining method consisting of a combination of heating and pressing treatments has been proposed, in which a penetrating alternating magnetic field is applied and the joining surface is heated and pressed by an induced current induced by this alternating magnetic field, and the point is that the joining work is quick and simple. However, although there is a marked improvement, nothing is mentioned about trying to solve the above problems in the case where the steps of winding and rewinding the steel slab are added.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a coiling method that occurs in continuous hot rolling in which steel pieces that have undergone rough rolling and are wound into a coil shape are sequentially unwound while joining and finishing rolling the steel pieces. It is an object of the present invention to provide a rolling facility capable of avoiding breakage separation of a plate caused by the rolling facility.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a coiling / unwinding device for coiling a steel slab after rough rolling and sequentially rewinding the coiled steel slab, and this winding / rewinding. A cutting device that cuts the leading and trailing ends of the steel pieces that are sequentially rewound by the device, a trailing end portion of the steel piece that is previously rewound and cut, and a rewinding and cutting steel piece that is subsequently rewound and cut. A cutting device, in which a joining device that heats and presses and joins the tip portions in a state of being abutted with each other, and a hot finish rolling mill group that continuously rolls the joined steel pieces are arranged. The continuous hot rolling equipment for steel bills is characterized in that a leveler equipped with a guide for guiding the tip of the steel bills between the rollers is disposed on at least one of the inlet side and the outlet side of the steel billet.

FIG. 1 shows the construction of equipment according to the present invention. In the figure, 1 is a rough rolling mill, 2 is a billet winding / unwinding device, and 3 is a leveler which is a combination of a plurality of rollers. A guide 3a for guiding the tip of the steel piece is provided on the entrance side of the leveler, and by passing the guide 3a, the winding curl remaining in the unwound steel piece is reduced.
Further, 4 is a cutting device (such as a crop shear) for processing the front end and the rear end of the steel slab to a desired shape, and 5 is a steel slab that is previously rewound and cut (hereinafter referred to as a preceding steel slab) Heat the end and the tip of the rewound and cut steel slab (hereinafter referred to as the trailing slab), butting each other,
As a joining device for pressing and joining, specifically, as the joining device 5, a device for applying an alternating magnetic field as disclosed in Japanese Patent Laid-Open No. 4-89109 is suitable. Here, in the case where the joining device 5 does not have a mechanism capable of moving in synchronization with the billet (fixed type), a billet storage device is added separately. Reference numeral 6 is a scale breaker for removing the scale formed on the surface of the steel piece after the joining treatment, and 7 is a hot finish rolling mill group. In addition, leveler 3
It is more preferable in operation to provide a pinch roll and a guide 3a on the entrance side of the so that the steel slab is pushed into the leveler.

[0009]

[Function] Steel pieces S ₁ and S roughly rolled and wound into a coil
_{In the} continuous hot rolling in which ₂ is sequentially unwound, and the finish end rolling is performed after joining the trailing end of the preceding billet and the leading end of the trailing billet,
As described above, in the rewinding of the steel slab, since the rolling curl as shown in FIGS. 2a and 2b remains, the butt of the steel slab causes a plate shift, so that sufficient joining cannot be performed. It was the cause.

In the present invention, when the coiled steel pieces are unwound, the remaining curl is reduced by passing them through a leveler, and then the steel pieces are joined to each other. The plate deviation at the time of abutting the rear end portions) is extremely small, and therefore the breakage separation of the plates during rolling can be made very small. In addition, although the leveler 3 is shown as an example in which the leveler 3 is arranged on the entrance side of the cutting device 4 in the equipment having the above-mentioned configuration, the installation position is not particularly limited as long as it is on the entrance side of the joining device 5, and the cutting device 4 is not limited thereto. It may be arranged on the exit side of the. Further, when passing the leveler 3, the steel slab may be passed through the entire length thereof, but only the front end portion and the rear end portion of the steel slab may be passed.

[0011]

EXAMPLE A plurality of sheet bar coils having a thickness of 20 to 50 mm, which are roughly rolled and wound up, are successively rewound by applying the equipment shown in FIG. 1 above, and then the roll diameter is 450 mm, Pitch is 500 mm, the number of rolls is 2 upper and 3 lower, and the intermesh is 0 mm to -5 mm (The intermesh is the upper and lower roll distance G, and the sheet bar thickness is GH.
The sheet bar is joined at its leading end and its trailing end through a leveler having the amount shown in Fig. 3), and then hot finish rolling is performed to examine the fracture separation state of the plate during rolling. As a result, in the case where the sheet bar coil passed through the leveler at the time of rewinding, the warp of the sheet bar due to the curling was extremely small within ± 5 mm, and there was no break separation of the plate during rolling, and stable rolling was possible. I was able to do it. On the other hand, when the sheet bar coil is simply unwound, joined and finish-rolled (no straightening at the rewinding tip), the warp of the sheet bar at the entrance side of the joining device is about 10-40 mm. It was confirmed that the strength when joining the sheet bars to each other was not sufficient and the plates were frequently broken and separated, making it difficult to achieve stable operation.

[0012]

According to the present invention, it is possible to reduce the winding curl which is a problem when rewinding a sheet bar wound in a coil shape, and particularly, the steel pieces wound in a coil shape are successively wound. In continuous hot rolling in which unwinding, joining, and rolling are performed, it is possible to avoid fracture separation of the plate as much as possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of equipment according to the present invention.

FIG. 2A and FIG. 2B are views showing a rewinding condition of a steel slab.

FIG. 3 is an explanatory diagram of a leveler.

[Explanation of symbols]

 1 Rough rolling mill 2 Winding / unwinding device 3 Leveler 4 Cutting device 5 Joining device 6 Scale breaker 7 Finishing rolling machine

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location B23K 20/04 E 9264-4E (72) Inventor Takao Yume 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba In Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Inventor Toshisada Takechi 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture In Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Address: Inside the Chiba Works, Kawasaki Steel Co., Ltd. (72) Norio Takashima, No. 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Inside the Chiba Works, Kawasaki Steel Co., Ltd. (72) Toshiro Matsushita Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 1 Ishikawajima Harima Heavy Industries Co., Ltd. Yokohama No. 2 Factory (72) Inventor Keigo Murakami No. 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishikawa Harima Heavy Industries Co., Ltd. Yokohama in the second factory

Claims (1)

[Claims] 1. A winding / rewinding device for winding a roughly rolled steel slab into a coil and sequentially rewinding the rolled steel slab, and a steel sequentially rewound by the winding / rewinding device. A cutting device that cuts the front and rear ends of the strip, and the rear end of the steel strip that was previously rewound and cut, and the tip of the steel strip that was subsequently rewound and cut in its butt state , A facility comprising a joining device for pressing and joining and a hot finishing rolling mill group for continuously rolling joined steel pieces, wherein at least one of an inlet side and an outlet side of the cutting device is provided. A continuous hot rolling facility for billet, wherein a leveler equipped with a guide for guiding the tip of the billet between the rollers is arranged in the.