JP2622458B2 - Slab charging device for heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace for holding or heating a slab supplied at a high temperature in a hot rolling in a heating furnace and performing endless rolling.

[0002]

2. Description of the Related Art Conventionally, when hot rolling a slab, slabs extracted from a heating furnace are rolled one by one to form a strip. However, the leading end and the trailing end of the strip are liable to cause line trouble. It is known that the truncation of the leading end and the trailing end due to a product defect occupies a large ratio with respect to the stationary part and lowers the yield. In order to solve this, for example, Japanese Patent Application Laid-Open No. 55-22465,
As seen in JP-A-3-13896, so-called endless rolling is employed, in which the rear end of the preceding slab and the front end of the succeeding slab are sequentially joined immediately before hot finish rolling, and this is continuously rolled. I have.

On the other hand, reduction of calorific value per unit in the heating furnace,
In order to improve the yield, a so-called direct-feed rolling technique is employed in which a high-temperature slab supplied from a continuous casting line is charged into a heating furnace within a short time, or is directly used for rolling. This is described in, for example, “Iron and Steel Association, 2nd Edition, Recent Hot Strip Manufacturing Technology in Japan (P.42).
-) S62 / 8 ". Simultaneously carrying out the endless rolling technology and the direct rolling technology,
Reduction of heat intensity, improvement of product yield, improvement of product quality,
Or, it is preferable in all aspects such as reduction of line trouble.

[0004]

A heating furnace capable of coping with both the direct rolling technology and the endless rolling technology,
It is required that the slab supplied from the continuous casting line can be charged into the furnace without excess or shortage, and that one endless batch of slab can be quickly supplied to the endless rolling line. Here, one endless batch refers to a group of slabs in which a preceding slab and a succeeding slab are connected and continuously rolled. Such heating furnaces include: (a) supply of slabs from a continuous continuous casting line; (b) intermittent slab dispensing which requires a fixed heating furnace and one endless batch for endless rolling quickly and at once. The gap between the preceding slab and the following slab is generated inside the heating furnace due to the disagreement between the two conditions. Therefore, the following problem occurs. (1) Since a gap is formed between the succeeding slab and the preceding slab in the heating furnace, the extraction of the succeeding slab is delayed and the endless rolling is interrupted because it cannot catch up with the preceding slab before the finish rolling mill. (2) A gap is formed between the slab and the preceding slab in the heating furnace, which causes a difference in furnace stay time, and a slab which is not sufficiently heated is extracted. (3) In the heating furnace, a gap is formed between the slab of the preceding lot and the slab of the preceding lot, so that the heating capacity deteriorates.

[0005] An object of the present invention is to provide means for solving the above-mentioned problems that occur in a heating furnace that performs batch heating in a line that combines a direct-feed rolling technique and an endless rolling technique.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a slab directly fed from a continuous casting line is kept or heated, and a preceding slab and a succeeding slab are connected at a finish rolling input side, and then continuously rolled. A slab charging apparatus for an endless rolling heating furnace, comprising a charging machine having a stroke longer than the total slab width of one endless batch.

[0007]

The operation of the present invention will be described with reference to the drawings. FIG.
1 is a schematic vertical sectional view of a heating furnace according to the present invention. Heating furnace 1
A heating device 2 is arranged in the inside, and the slab 4 is transferred to the extraction end 5 side while being heated in the furnace by a conveying means 3 such as a walking beam. A slab loading device 7 is provided on the loading end 6 side.

FIGS. 2 to 4 are explanatory views showing the movement of the slab traveling in the heating furnace. FIG. 2 shows a state in which the loading and extraction of the slab are matched, and FIGS. In FIG. 2, (a) a part of the first endless batch 11 and a part of the second endless batch 12 are heated in the heating zone 14 in the furnace 10 for exclusive use of the direct-feed slab, and a part of the second endless batch 12 is heated. The slab is in the pre-tropical zone 15, and the second half of the second endless batch 12 is being transported to a heating furnace or being cast on a continuous casting line. (B) shows a state where the dispensing of the slab of the first endless batch 11 is completed. First endless batch 11
At the end of the rolling, the rolling slab 13a of the third endless batch 13 arrives at the charging end of the heating furnace from the continuous casting line. (C) The slab 13a that has arrived is loaded by the slab loading device 7 until immediately after the preceding slab.

In the case of FIG. 3, as shown in FIG.
This shows a case where a part of the slab 12a of the second endless batch 12 arrives with a delay from the continuous casting line when the slab of the first endless batch 11 is completely discharged. At this time, the slab 12a charged into the furnace by the conventional charging machine 8 has a gap 9 between the slab 12a and the preceding slab, as shown in FIG.

FIG. 4 shows FIG. 4 in the same state as FIG.
When (b) is reached, the charging machine 7 capable of inserting the slab 12a arriving with a delay at the tail end of the second endless batch 12 without forming a gap is shown (FIG. 4 (c)).
Since the charging machine 7 has a stroke longer than the sum of the slab widths of one endless batch, as shown in FIG.
Can be supplied to the tail end to achieve the intended purpose.

[0011]

EXAMPLE A heating furnace of an example operated under the following operating conditions will be described. 1) Steel material thickness 250 mm, width 1 m, endless batch is 15 slabs / time. Therefore, the total slab width of the endless batch is 15 m. 2) Heating furnace length 25m (heating zone 20m, pre-tropical 5m) 3) Heating furnace slab charging device stroke length 15m (same length as total slab width of endless batch) 4) Extraction pitch 60s / 1 slab during endless rolling 5) Heating furnace extraction slab temperature 1100 ° C During the endless rolling, if the slab is supplied from the continuous casting line with the maximum number of rolls, the rolling is interrupted in the heating furnace with the shortest machine length to secure the necessary heating time, and the heating waits. In order to prevent the temperature of the slab arriving from the continuous casting line from dropping during this time, the slab is charged into the pre-tropical zone shown in FIG.

However, since endless rolling is extremely efficient, if a slab is not supplied from the continuous casting line during endless rolling, a gap is formed between the succeeding slab and the preceding slab in the heating furnace. I can do it.
With the conventional charging device having a stroke of about 7 m, this gap cannot be filled, the extraction time is extended, the succeeding slab cannot catch up with the preceding slab in front of the finishing mill, and the rolling of the second endless batch is interrupted. I have.

[0013] Therefore, by setting the stroke length of the heating furnace slab charging device to 15 m, the succeeding slab can be loaded in the heating furnace without forming a gap between the succeeding slab and the preceding slab. The rolling of the second endless batch could be performed without interruption.

[0014]

According to the present invention, even if the slab arriving from the continuous casting line is delayed, no gap is formed between the slab and the preceding slab in the heating furnace. Therefore, the succeeding slab cannot catch up with the preceding slab in front of the finish rolling mill due to the delay of the extraction time, and the endless rolling is not interrupted.

Further, since there is no gap between the slab and the preceding slab in the heating furnace, the heating capacity does not deteriorate.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a heating furnace according to the present invention.

FIG. 2 is an explanatory diagram showing a movement of a slab traveling in a heating furnace.

FIG. 3 is an explanatory view showing the movement of a slab traveling in a heating furnace.

FIG. 4 is an explanatory diagram showing a movement of a slab traveling in a heating furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Heating device 3 Conveying means 4 Slab 5 Extraction end 6 Charging end 7,8 Slab charging device 9 Gap 10 Heating furnace 11 1st endless batch 12 2nd endless batch 13 3rd endless batch 14 Addition Tropical 15 pretropical

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Rikio Takeshima 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Corporation Chiba Works (72) Inventor Toshisada Takechi 1 Kawasaki-cho Chiba City Kawasaki Steel Corporation Chiba Works ( 56) References JP-A-1-200189 (JP, A) JP-A-3-223415 (JP, A)

Claims (1)

(57) [Claims] 1. A slab charging apparatus for a heating furnace which heats or heats a slab directly fed from a continuous casting line and supplies the slab to an endless rolling step, wherein a slab having a stroke longer than the sum of slab widths of one endless batch is loaded. A slab charging device for a heating furnace, comprising an input device.