JP2915264B2 - Hot coil manufacturing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hot coil and an apparatus therefor.

[0002]

2. Description of the Related Art As is well known, a typical hot coil manufacturing facility is called a hot strip mill, which is a unitary weight of 15 to 50 manufactured by a continuous casting machine.
It is equipment for reheating a ton slab to about 1100 ° C. to 1300 ° C. to form a coil. Specifically,
A walking beam type heating furnace for reheating cold rolled material (slab) produced by a continuous casting machine, a rough rolling machine for rolling the reheated rolled material into a coarse bar, and further converting the coarse bar into a thin plate It is generally composed of a finishing mill for rolling, a strip cooling device for cooling a rolled thin plate (strip), and a down coil for winding the cooled thin plate.
The primary scale generated during the reheating is blown off by the high-pressure water spray descaler, and the secondary scale generated during the rolling is blown off by the high-pressure water spray descaler at the entrance of each rolling mill, and each is removed. .

By the way, recently, this hot strip mill has been improved, and a facility called a near-net-shape system excellent in yield and energy saving has been proposed and partially implemented (for example, Japanese Patent Publication No. Hei 5-13722). And Japanese Utility Model Application Laid-Open No. Sho 61-102301).

This is a facility provided with a continuous casting machine and a rolling mill in a continuous manner. This conventional example will be described with reference to FIG. 1 is a curved continuous casting machine, 2 is a rolling mill, and both are connected via a cutting device 3 and a heating and holding furnace 4. The continuous casting machine 1 generally includes a tundish 5, a mold 6, and a roller apron 7, and the rolling mill 2 includes a high-pressure water spray descaler 8, a hot tandem quadruple rolling mill 9, and a coiler 10. . In such a continuous casting machine direct-coupled rolling mill, the line speed must be adjusted to the lower speed, and the casting speed of the slower continuous casting machine 1 (2 to 3 m /
min) about 5 to 6 m / min for a thin plate slab, which is much lower than a general rolling speed), and the insertion speed of the rolled material 11 into the rolling mill 2 is reduced by half compared to a general hot strip mill. (At most, about 14m /
min).

The inventors of the present invention have analyzed the quality of a coil product manufactured by such a continuous casting machine direct-coupled rolling mill in a multifaceted manner in comparison with a coil product manufactured by a general hot strip mill. Found the following problem.

In general, when iron is brought into contact with oxygen or air while in a high temperature state, a film of a reaction product, that is, scale is formed on the surface thereof. First, oxygen is activated and adsorbed on the iron surface, The surface is positively ionized and oxygen is negatively ionized, and an extremely thin oxide film is immediately (several seconds) generated due to this potential difference. Therefore, even if this generated scale can be blown off with a high-pressure water spray descaler and removed, the internal heat of the rolled material is restored to the surface and new scales are generated one after another. It is greatly affected by the temperature and the time the rolled material comes into contact with oxygen.

However, as described above, in the continuous caster direct-coupled rolling mill, the speed of inserting the rolled material 11 into the rolling mill 2 is limited. Even if the surface is cooled, this rolled material 11
Then, the heat regained to the surface by the internal heat becomes large,
A new scale is created. As a result, it has been found that the newly formed thick scale layer is rolled into the hot coil product itself by the rolling mill 2, and that the plastic elongation characteristic of the coil product is significantly reduced.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. The gist of the invention is as follows: 1) A continuous casting machine is connected, and a rolling mill is provided at a subsequent stage. After cutting the slab manufactured by the continuous casting machine, the slab is inserted into a heating furnace, and the temperature of the slab is adjusted while increasing the moving speed of the slab in the heating furnace.
In a hot coil manufacturing method characterized by being inserted into a rolling mill at a speed of at least not less than 2 in and rolling, and 2) directly connected to a continuous casting machine in which a continuous casting machine is connected and a rolling mill is provided at a subsequent stage. In a shape rolling mill, between a continuous casting machine and a rolling mill, a slab cutting machine, a heating furnace, and a scale breaker for repeatedly bending a plurality of rolls at a subsequent stage of the heating furnace are provided. 3) the slab stored in the heating furnace according to claim 1 which is in the coil manufacturing apparatus;
A method of manufacturing a hot coil inserted into a rolling mill at a speed of 30 m / min or more.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail by means of an embodiment shown in the accompanying drawings. FIG. 1 shows an apparatus according to an embodiment of the present invention. The same or equivalent parts as those in the conventional example shown in FIG.

In the continuous casting machine 1 of this embodiment, the slab as the rolled material 11 has a single weight of about 50 tons and a casting speed of about 5 to 6 m / min. The continuous casting machine 1 is not limited to the curved type, and a twin roll or twin belt type continuous casting machine may be used.

In FIG. 1, a continuous casting machine 1 and a rolling mill 2 are connected via a torch type cutting device 3 and a walking beam type heating furnace 12. This walking beam type heating furnace 12 is a kind of a so-called continuous furnace similar to the equipment arranged in a conventional hot strip mill, and includes a moving beam and a fixed beam that repeat a cycle of ascending, traveling, descending, and reciprocating. Or a combination of moving beams. The rolling material 11 stored in a heating furnace at a predetermined speed is supplied to the rolling mill 2 at a predetermined speed while being laterally fed. In this embodiment,
A carrier chain may be used in the continuous furnace, and any material may be used as long as it can increase the moving speed of the rolled material 11 to the rolling mill 2 and can supply the rolled material 11 to the rolling mill 2 at a desired speed. In FIG. 2, the rolled material 11 manufactured by another continuous casting machine arranged side by side is stored in another walking beam type heating furnace 12 ′ and supplied alternately to the same rolling mill 2. .

Also, the walking beam type heating furnace 1
Next to the rolling mill 1, a scale breaker 13 that repeatedly bends with a plurality of rolls having the same mechanism as the roller leveler is arranged to peel off the scale.
The high pressure water spray descaler 8 is arranged in front of the first stand. Further, between the stands of the rolling mill 1, induction heaters 14 and 14 are arranged for improving heat retention.

Therefore, according to the apparatus of this embodiment, the rolled material 11 produced at a relatively low casting speed by the continuous casting machine 1 is cut into a predetermined length by the torch type cutting device 3, and the walking beam type heating device It is sent to the furnace 12. In this walking beam type heating furnace 12, the rolled material 11 is adjusted to a temperature necessary for rolling, as in a normal hot coil mill, and increases to a predetermined insertion speed.
For example, the insertion speed is increased to at least 30 m / min. The rolled material 11 adjusted in this manner is peeled off from the scale firmly adhered by the scale breaker 13, and then, by the high-pressure water spray descaler 8.
This is removed. Immediately thereafter, it is inserted into the rolling mill 2,
Formed into coils. In the present embodiment, the rolled material 11 is expressed as a slab, but it goes without saying that this includes a billet and a bloom.

[0014]

As described above, according to the present invention, the continuous casting machine and the rolling mill are directly connected to each other, and the cast slab is immediately rolled. Therefore, the yield is improved and the energy is saved as compared with the conventional hot strip mill. At the same time, while improving productivity,
It is possible to obtain a coil product having a quality equal to or higher than that of a conventional hot strip mill.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a view as seen from arrows a to a in FIG.

FIG. 3 is a conceptual diagram of a conventional continuous casting machine direct-coupled rolling mill.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Continuous casting machine, 2 ... Rolling machine, 3 ... Cutting device, 11,1
1 ': rolled material, 12: walking beam heating furnace, 1
3: Scale breaker

Claims (3)

(57) [Claims] 1. A slab produced by the continuous casting machine is cut and then inserted into a heating furnace, and the slab is moved in the heating furnace. Adjust the temperature of the slab while increasing, 30m / m
A method for producing a hot coil, wherein the hot coil is inserted into a rolling mill at a speed of at least in. 2. A continuous casting machine directly connected to a continuous casting machine, and a rolling mill provided at a subsequent stage, wherein a slab cutting machine, a heating furnace, The
A stage in which multiple bends are repeatedly applied to the subsequent stage of the heating furnace.
An apparatus for manufacturing a hot coil, comprising a kale breaker . 3. The slab stored in the heating furnace according to claim 1,
Hot core inserted into rolling mill at speed of 30m / min or more
Manufacturing method of il.