JPS6018203A - Line of direct rolling equipment - Google Patents

Abstract

PURPOSE:To obtain a line of direct rolling equipment capable of reducing a heat to be charge by providing a heating device, for heating the end faces of a slab, to the rear side of a cutter succeeding a continuous rolling mill. CONSTITUTION:Heating devices 10, 10 are respectively provided to the rear sides of cutters 2, 2 succeeding continuous rolling mills 1, 1. The devices 10, 10 are preferably installed at the positions located in close proximity to the cutters 2, 2 and where the cutters 2, 2 are not allowed to travel. In this case, the temperatures of the end faces of a slab are not so cooled at the time of charging the slab to the device 10 that the heat quantity required for heating it is saved. Then the heat to be charged is reduced to 1/2-1/3 the heat required for the same purpose at the conventional arrangement of devices, when both are compared with each other. Moreover, in addition to said constitution, a heating device 11 is installed at the front side of a finishing mill 5. The device 11 is used especially for manufacturing a thin material or a thin aluminum killed steel, because an extremely high temperature is required at the inlet of the mill 5 when these thin materials are rolled.

Description

[Detailed description of the invention] The present invention relates to a direct rolling mill train.

In recent years, for the purpose of energy saving, direct rolling has been implemented, in which a continuous casting device is directly connected to rolling equipment, and a high-temperature slab obtained by the continuous casting device is directly rolled.

Figure 1 shows an example of this direct rolling pool facility.

In the figure, 1 is a continuous casting machine, and in this example, two strands are disposed. A cutter 2 is connected to the continuous casting +81, and the slabs cut by this cutter are traversed by a collecting truck 3 and sent to a rolling process.

4 is a rough rolling mill, 5 is a finishing mill, and in front of the rough rolling mill 4 there is a heating group fi 6 for heating the end face of the slab; A heating device t is provided for heating to the required temperature.

By the way, in aluminum killed steel sheets, in order to ensure good deep drawability, it is necessary to bring AA and N into a solid solution state at the time of hot rolling steel sheets, and to precipitate them as AIN during annealing after cold rolling. A. It is said that 6N begins to precipitate gradually when the temperature drops below 1100℃, but in order to suppress the precipitation of K13N to a range where there is no river between the material and the material, it is necessary to adjust the slab temperature from the continuous casting machine to the rough rolling mill. It is known that it is necessary to maintain the temperature at 900°C or higher. 900 again
'C: Even if it is below, if the time is short,
Reheat to 1200'C or higher or 1150°C x 5
It is known that reheating for more than a minute is sufficient.

However, in an actual continuous casting machine, the temperature of a part of the end face corner of the slab drops to around 80° C. in the extremely cold zone. Therefore, reheating is performed using the heating device 6 described above at a temperature of 1200° C. or higher or 1150° C. for 5 minutes or more in order to solidify AS and N again.

Figure 2 shows the temperature change at the end face of the slab during the manufacturing process. As shown by the dotted line, it is reheated by the heating device 6 and reheated to 1200°C or higher, and the temperature is lowered again in the rough rolling mill 4.
The temperature is raised in the heating device I, and then the temperature is lowered in the finishing mill 5, and the finished product is finished at a predetermined finishing temperature.

However, in the conventional equipment array, since the heating device 6 is provided downstream of the collecting truck 3, the slab temperature drops significantly before it enters the heating device 6, resulting in a disadvantage that a large amount of energy is used for reheating. was there. (B) in Figure 2
indicates the amount of temperature increase, and it can be seen that a large amount of heat input is required.

The present invention has been developed in view of the above-mentioned points, and it is an object of the present invention to provide a new direct rolling mill train.

FIG. 3 is a layout diagram showing a seventh embodiment of the present invention, in which a heating device io for heating the end face of the slab is provided downstream and rearward of the cutter 2;
Cutting time using the cutter 2, which may be equipped with an io, generally takes 3 to 7 minutes, and during this time the leading end of the slab is in a state of waiting until the cutting of the trailing end is completed.7. On the other hand, after cutting is completed, the slab is 60~1
Since the conveyance is carried out at a high speed of 20 m/min, the conveyance time from the cutting to the rough rolling mill is long. Excluding quality checks such as the flaw detector, hot scarfer, and device for removing paris generated by the cutter, the process is as short as 1 to 5 minutes, for example.

Moreover, this time is longer than the required time for transportation.

Considering this point, the above-mentioned waiting time for cutting is negligible from the viewpoint of direct rolling, where the slab is charged into hot rolling at high temperature and then rolled as it is! The temperature drop of the material can be ignored. For this reason, there is a plan to reduce the temperature drop in the slab by installing a heat insulating cover around the cutter 2, but either method reduces the temperature drop due to the internal recuperation effect, and the temperature drop does not change. There isn't.

So with this invention! -1, heating device 10 behind cutter 2
．． 10 is provided.

Therefore, it is better to install the heating device 10 as close to the cutter 2 as possible, but the location where the cutter 2 travels requires a complicated control mechanism, making the device complex and expensive. A position where the nearest cutter 2 does not travel is desirable.

The solid line in FIG. 2 shows the temperature curve according to this embodiment, and since the end surface temperature of the slab is not so cold when it is loaded into the heating device 10, the temperature rise -1t(A) can be small. . Comparing this with the conventional equipment row, q input heat soaking results in soil ~ ↓.

3 The conditions for obtaining the solid line in Figure 2 are as follows.

Slab dimensions: Thickness 220 mm x width 1100 mm x length 900 mm
0 Ren: Mad 7J Manufacturing speed: 2.2y+z/min Product dimensions: Thickness 1.6 Mx Width IHJOmv+Heating device 10: Gas combustion type end heating device Equalize the temperature.

In addition to the above configuration, a heating device 1 is further provided in front of the finishing rolling mill 5.
1 is installed. This heating device ItI 1 is particularly suitable for producing thin materials (1.6 vnrt to 1.2 mrn) and thin aluminum killed steel (2.0 to i, 6 am). That is, for such a thin material, a very low temperature is required as the entrance temperature of the finishing mill 5.

On the other hand, the inventors of the present invention raised the temperature of the material at the entrance side of the finishing rolling mill. The ratio of the amount of temperature rise of the material on the entry side of the finishing rolling mill to the amount of temperature rise increases. Therefore, heating by the heating device 10 has a very small temperature increasing effect on the side of the finishing mill 5, which is preferable in terms of energy saving (this is because heating immediately before the finishing rolling mill 5 is advantageous).

However, the passing speed between the rough rolling percolation section and the finish rolling mill section is normally as fast as 60 to 200 m/min, and the heating time is generally only about 10 to 20 seconds. In the past, it is desirable that the heating device 11 be a device that can raise the temperature to a large extent in a short period of time. It may also be something that heats the whole thing.

Note that the target temperature for heating devices io and ii is based on the
As shown in No. 21330, heating is performed to make the temperature the same as the center temperature, and only to achieve solid solution of Al3N or to ensure the finishing temperature of the rolling line.

In addition, it is desirable to prevent the fall of ar 11f by using heat insulating covers, etc. in the cutter zone, transfer table, etc. as much as possible.

Table 1 below shows a comparison of the total fuel consumption in the present invention and the conventional example shown in FIG.

Table 1 Note that in the implementation row shown in FIG. 3, a heat retention facility 12 is provided in the furnace before the rough rolling fμ4. With this heat retention equipment 12,
In the event of equipment failure, the remaining slab is placed here to maintain the temperature of the slab.

This heat retention equipment 12 may be provided in a bypass instead of a line.

Analysis of sudden line stoppages shows that there are 3 stoppages of 5 minutes or less.
The most frequent pause was 9 pauses, followed by 6-10 minute pauses at 36%. Therefore, if the heat retention equipment 12 is used to deal with these short-term stoppages, a large yield increase will be achieved. Table 2 and Table 3 below, which may show the paste density in the case, show the HD RiJ' performance dimensions with and without the heat retention equipment 12.

With this heat retention equipment 12 shown, even if there is a line stoppage, the
(It can be seen that the range of plate thicknesses that can be used for D R is expanded).

As explained above, according to the direct rolling equipment row of the present invention,
Since a heating device is provided at the rear of the cutter, the amount of heat input can be reduced. Furthermore, when a high finishing temperature is required, a heating device in front of the finishing rolling mill can be used to efficiently heat the material.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a conventional 1α contact rolling equipment row, FIG. 2 is a graph showing changes in slab edge temperature, and FIG. 3 is a layout diagram showing an embodiment of the present invention. 10 and 11... Heating 'J Ft + 12... Heat retention equipment. Patent applicant Nippon Kokan Co., Ltd. Inventor Tera 1) Double amount Sum 1) Trend Raido Shiraishi Akira Kodoi Fudo Tera, Taku Masaru Uchi

Claims (2)

[Claims] (1) In a direct rolling equipment line having a continuous rolling mill and a cutter, and a rough rolling mill and a finishing mill that roll the slab cut by the cutter, heating is performed to heat the end face of the slab behind the cutter. A direct rolling mill row characterized in that it is equipped with a device. (2) In a direct rolling equipment line having a continuous rolling mill, a cutter following the continuous rolling mill, and a rough rolling mill and a finishing mill for rolling the slab cut by the cutter, the end face of the slab is heated at the rear of the cutter. A direct rolling mill array characterized in that a heating device is provided and a heating device for heating a rough bar is provided in front of a finishing rolling mill.