JPS626749A - Method and installation for continuous casting - Google Patents

Abstract

PURPOSE:To improve casting capacity by dividing ingot guide roll groups to plural groups and starting the casting of the next succeeding ingot during rolling of an ingot. CONSTITUTION:The ingot guide roll groups 3 consisting of guide rolls or pinch rolls are divided to a plurality and the roll groups 3A-3D which are independently controlled in speed by a roll speed control device 4 are disposed. An ingot detector 5 and a drawing detector 6 are installed on the outlet side of the roll group 3A and roll group 3D below the mold 1. The detectors 5, 6 have pulse generators 5A, 6A and counters 5B, 6B and execute tracking of the preceding ingot S1 and the succeeding ingot S2. The roll groups are changed from the drawing mode to the casting mode and the next casting is started after the passage of the rear end of the preceding ingot S1 through the roll groups 3A-3D. The casting capacity is increased by such method.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a continuous casting method and continuous casting equipment in which a dummy bar is inserted from above, which is extremely effective especially when directly connected to a hot rolling line. It is.

<Prior art and its problems> In recent continuous casting, for example, there is a method in which slabs cast using curved continuous casting equipment are first made into cold slabs, then reheated in a heating furnace and rolled. The casting line and rolling line are directly connected, and the slab after casting is immediately transferred to the rolling line while being kept warm for rolling (direct rolling), or alternatively, the casting line exit side and the rolling line entry side Methods such as installing heating equipment between the slab and slightly raising the temperature by supplementary heating and rolling (direct charging) have been put into practical use from the viewpoint of effective use of slab heat and improvement of production efficiency. .

What is important in such continuous casting is to keep the temperature of the slab at the outlet of the casting equipment as low as possible and to match the process with a hot rolling line with high throughput.

In conventional continuous casting, as shown in Fig. 4, there is a casting mode in which molten steel is continuously injected into the mold 1 from the tundish 2, and as shown in Fig. There is an independent drawing mode for pulling out the slab, and the slab guide roll group 3 is the same section that is driven synchronously.

Here, the drawing speed of the slab is different between the casting mode and the drawing mode, and the drawing speed of the casting mode is lower than that of the drawing mode from the viewpoint of preventing internal cracks and breakout of the slab. In the conventional method without a control section, the next casting cannot be started until the drawing mode is completed (the final slab passes through the exit side of the pinch rolls).

Here, the pull-out time in pull-out mode is pull-out time = machine length (mold pinch roll exit side) ÷
It is expressed as the average drawing speed (in drawing mode), for example, if the machine length is 46 m and the average drawing speed is 1.
At 5 rIL/min, it takes about 29 minutes.

In the case of the dummy bar upward insertion method, the preparation time around the mold is shortened to about 10 to 15 degrees, so the preparation time is determined by the drawing time. Therefore, the production efficiency is reduced by this drawing time.

On the other hand, various methods have been proposed in which preceding casting and subsequent casting are performed continuously (for example, Japanese Patent Laid-Open No. 55-8329
Publication No. 157556/1983, Japanese Patent Application Laid-Open No. 1982-157556
-177B65 Publication), in any case, the casting speed must be reduced at the initial stage of subsequent casting, and a drop in temperature of the preceding slab is unavoidable, and in direct connection with the hot rolling described above, It is disadvantageous.

This invention was proposed in view of the above circumstances, and its purpose is to be able to start casting a trailing slab while the leading slab is being drawn in the normal drawing mode, thereby increasing casting capacity. The object of the present invention is to provide a continuous casting method and continuous casting equipment that can improve the temperature of the preceding slab and prevent the temperature of the preceding slab from decreasing.

<Means for Solving the Problems> The continuous casting method according to the present invention includes: dividing the slab guide roll group of the continuous casting equipment into a plurality of groups, and controlling the roll speed of each roll group independently; 2
By tracking the slab with two slab movement amount detectors, the group of slab guide rolls through which the rear end of the preceding slab that is moving in the drawing mode is changed to the casting mode, and the The casting of the next succeeding slab is started, and the next succeeding slab can be poured while the preceding slab is being drawn in the normal drawing mode.

The continuous casting equipment according to the present invention includes a group of slab guide rolls that are divided into a plurality of groups and whose roll speeds are controlled independently, and a group of slab guide rolls that are installed below the mold to control the amount of movement of the slab during pouring. a casting detector capable of detecting the casting; a drawing detector installed on the slab drawing side and capable of detecting the amount of movement of the slab during drawing; processing output signals of the casting detector and the drawing detector; Equipped with a roll speed control device that controls the roll speed of each group of slab guide rolls, a casting detector and a withdrawal detector track the slab, and the roll speed control device allows the rear end of the preceding slab to pass. The slab guide roll group is changed to the casting mode, and while the preceding slab is being pulled out, the next trailing slab is started to be poured.Furthermore, the roll speed control device is used to control the speed of each slab so that the dummy bar and the leading slab do not collide. The roll speed of the slab guide roll group is adjusted.

<Example> The present invention will be described below based on an illustrated embodiment.

As shown in FIG. 1, the slab guide roll group 6 consisting of guide rolls or pinch rolls is divided into, for example, four parts,
Roll groups 3A and 3B whose speeds are independently controlled by a roll speed control device 4.

Let them be 3C and 3D.

On the exit side of the roll group 5AN and the roll group 3D below the mold 1, a casting detector 5 and a drawing detector 6, which can detect the amount of movement of the slab during casting and drawing, are installed.

The detectors 5 and 6 are composed of pulse generators 5A, 6A and counters 5B and 6B, and this movement amount signal is input to the calculation device 7, and the moving amount signal is inputted to the calculation device 7, and the leading slab S1 and the trailing slab S
2 tracking is performed.

When the rear end of the preceding slab S1 passes through each roll group 3A to 3D by this tracking, the roll group is changed from the drawing mode to the casting mode during drawing, and the rear end of the preceding slab S1 passes through the drawing detector 6. At the stage of passing, all roll groups 3A to 3D
to the conventional casting mode.

Further, the drawing speed in the casting mode is adjusted so that the distance between the dummy bar 8 and the preceding slab S1 does not become less than 50 cm, for example, so that the dummy bar 8 and the preceding slab S1 do not collide.

Tracking is carried out by, for example, detecting the amount of movement of the preceding slab S1 after the rear end of the preceding slab S1 passes the casting detector 5 with the withdrawal detector 6, and then detecting the amount of movement of the preceding slab S1 from the known distance between the detectors 5 and 6. This is performed by calculating the distance ΔL between the detector 6 and the rear end of the slab S1 in the arithmetic unit 7.

The distance between the dummy bar 8 and the preceding slab 81 is also calculated by the calculation device 7 from the casting length L+ and the dummy bar lengths Lo and ΔL.

The roll speed control device 4 has built-in sequences of a drawing mode, a casting mode during drawing, and a casting mode, and the sequence of the casting mode during drawing during the transition period is as follows.

The rear end of slab S1 passes through roll group 3A → Stops driving roll group 3A ↓ Passes through roll group 6B → Stops driving roll group 3B ↓ In such a mode, when roll groups 3A and 3B are stopped, dummy par 8 is inserted. Then, perform mold sealing work, etc., move the tundish 2, and cast the next trailing slab S2.

For mold sealing work, a steel plate frame is placed on the upper end of the dummy bar located directly below the mold, and a sealing material (
This process involves filling the mold with a heat-resistant refractory (heat-resistant refractory) and sealing it with the side walls of the mold.

When casting starts, the roll groups 3A and 3B enter the casting mode, and when the preceding slab S1 leaves the drawing detector 6,
All roll groups are in casting mode.

Comparative Example> Figure 2 shows an example in which a low carbon material (C≦0.05%) was cast at an average drawing speed of 1.51 n/min.
As shown in Table 1, it was found that the time can be reduced by 12 minutes compared to the conventional method.

Figure 3 shows an example of casting medium carbon material (0.10≦C≦0.20chi) at an average drawing speed of 1.0 m/min. It was found that the time could be reduced by 16 minutes.

It can be seen that the slower the drawing speed, the greater the shortening effect.

<Effects of the Invention> As described above, in the continuous casting method according to the present invention, the group of slab guide rolls is divided into a plurality of parts and driven, and the group of rolls through which the trailing end of the preceding slab that is moving in the drawing mode is driven. By changing to the pouring mode, it is possible to start the next pour during normal drawing, improving casting capacity and preventing the temperature of the preceding slab from dropping, making it suitable for continuous casting equipment that is directly connected to hot rolling. It can be applied effectively.

Further, the continuous casting equipment according to the present invention can start casting during drawing with a relatively simple configuration.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the continuous casting equipment according to the present invention, Fig. 2 is a graph showing the relationship between the elapsed time from the start of the drawing mode and the position of the slab, and Fig. 6 is a similar diagram when the drawing speed is changed. Graph, Figure 4 is a schematic diagram showing the conventional casting mode, Figure 5
The figure is a schematic diagram showing a conventional extraction mode. 1...Moshiled, 2...Tanditshu, 3°! A,
5B, 50, 3D... Slab guide roll group, 41) Roll speed control device, 5... Casting detector, 6... Pulling detector, 5A, 6A... Pulse generator, '5B, 6B...
- Counter, 7... Arithmetic device, 8... Dummy bar. Figure 4 Figure 5

Claims (2)

[Claims] (1) In the continuous casting method that adopts the dummy bar upward insertion method, the slab guide roll group of the continuous casting equipment is divided into multiple groups, each roll group is independently controlled in roll speed, and the slab is tracked. By doing this, the group of slab guide rolls through which the rear end of the leading slab moving in the drawing mode has passed is changed to the casting mode, and the casting of the next trailing slab is started while the leading slab is being pulled out. A continuous casting method characterized by: (2) Continuous casting equipment that adopts the dummy bar upward insertion method includes a group of billet guide rolls that are divided into multiple groups and whose roll speeds are controlled independently, and a group of slab guide rolls that are installed below the mold and control the roll speed during pouring. a casting detector capable of detecting the amount of movement of the slab; a drawing detector installed on the slab drawing side and capable of detecting the movement of the slab during drawing; and the casting detector and the drawing detector. 1. Continuous casting equipment, characterized in that it is equipped with a roll speed control device that processes output signals and controls the roll speed of each group of slab guide rolls.