KR20040019723A - The control method of driven roll pressure in mold width change - Google Patents

Abstract

PURPOSE: A method for controlling roll force of driving roll is provided to improve surface quality of slab and control casting rate more accurately by accurately controlling roll force of an inclined slab using position information of the end side part of the mold when changing width of end side part of mold during casting. CONSTITUTION: In a method for controlling roll force of the driving roll in a continuous casting facility comprising a mold(2) capable of varying width of slab and a strand driving roll(5) for reducing and drawing the slab, the method comprises first step of capturing starting time point of width variation through driving roll reduction control system(7) and receiving width information of the mold; second step of calculating length of inclined slab by receiving casting speed from driving roll speed control system(8) at the same time when performing the first step; third step of periodically storing width of the slab into a memory device according to length of the inclined slab; and fourth step of controlling roll force of the driving roll by calculating accurate roll force for width of the corresponding slab as tracking movement of the inclined slab inside strand after performing the third step.

Description

Control method of rolling roll reduction when width is changed during casting {THE CONTROL METHOD OF DRIVEN ROLL PRESSURE IN MOLD WIDTH CHANGE}

The present invention is a continuous casting facility having a strand driving roll that serves to press down the mold and the cast slab to change the width during casting in the casting roll reduction to reduce the inclined cast slab generated when the mold width changes during casting It relates to a control method.

In general, the continuous casting method of an ironworks is to inject molten steel into a water-cooled mold, and then continuously draw it from below, forcing it to be cooled and solidified in a secondary cooling zone, thereby producing a predetermined cast (slab, bloom or billet) directly from the molten steel. to be.

The equipment used for the continuous casting is a tundish (1) for receiving molten steel transferred through the ladle through the steelmaking process, as shown in Figure 1, the molten steel is supplied from the tundish (1) to a predetermined cross-sectional shape TORCH CUTTER MACHINE (TCM) to take out the solidified mold (2), the roll (3) for bending and straightening the cast (4), the segment (3) consisting of a cooling stand, and the cooled cast to take out and cut it to a predetermined length. And so on.

When casting the width of the mold during casting through such a casting facility, the width of the cast steel before and after the width change is different, resulting in an inclined cast steel 4 'as shown in Figure 2, such a slanted cast steel 4' The length of is determined by the variable speed and casting speed.

Here, the casting speed is fixed to maintain the solidification cell in the mold during the variable width of the mold during casting, while the width variable speed is not constant because the speed is determined according to the width variable pattern.

Therefore, it is difficult in reality to produce a cast piece having a smooth and constant slope as shown in FIG.

In particular, the rolling force of the driving roll is generally determined in proportion to the width of the cast steel when casting conditions such as steel grade or cast steel thickness are determined.If the pressing force of the driving roll is set larger than the normal value, the casting roll is left on the surface of the cast steel. It will adversely affect the surface quality.

On the other hand, if the pressure reduction force of the driving roll is set less than the normal value, slip occurs between the cast steel and the driving roll, so that the operator cannot maintain the exact casting speed desired.

Therefore, despite the necessity of appropriately adjusting the rolling force of the driving roll according to the width of the cast steel, conventionally, when the width of the mold is changed during casting, the slab inclined in the strand is tracked so that when the inclined cast steel enters the driving roll, the narrow cast width By setting the pressure collectively on the basis of this, there were too many pieces of cast iron that were wasted, which was a waste of resources.

The present invention has been made in view of the above-described problems of the prior art, and has been created to solve this problem. The casting length information of the inclined cast pieces and the position information of the short side portions generated when the width of the mold short side portions during casting are changed in an online state. It is an object of the present invention to provide a method for controlling the driving roll reduction when the width of the casting is changed by improving the surface quality of the casting and controlling the casting speed by setting the driving roll reduction force appropriately for the width of the cast steel by measuring periodically.

1 is a schematic diagram of a typical continuous casting facility,

2 is an exemplary view showing an inclined cast steel that occurs when the width of the casting during casting,

Figure 3 is a block diagram of the configuration of the facilities for explaining the driving roll reduction control method when the width during casting in accordance with the present invention.

Explanation of symbols on the main parts of the drawings

2 .... Mold 3 .... Segment

4 .... casting 5 .... drive roll

6 .... Mould width variable control system 7 .... Drive roll reduction control system

8 .... drive roll speed control system

The above object of the present invention,

In the method of controlling the reduction force in a continuous casting facility having a mold and a cast drive roll that serves to push down the mold and the cast piece that can vary the width during casting,

A first step of capturing the width change start time and receiving the mold width information through the driving roll reduction control system;

A second step of calculating the length of the inclined cast piece by receiving the casting speed from the drive roll speed control system simultaneously with the first step;

A third step of periodically storing the width of the slab in a memory device according to the length of the inclined slab;

The fourth step of controlling the pressing force of the drive roll by calculating the exact pressing force for the width of the cast steel while tracking the movement of the inclined cast steel in the strand after the third step It is achieved by providing a drive roll reduction control method at the width change.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3 is a block diagram of a driving roll reduction control system for explaining a control method according to the present invention.

Referring to FIG. 3, the driving roll 5 installed in the segment 3 and driven by the driving roll motor M is installed to receive a pressing force by a pair of hydraulic cylinders C. As shown in FIG.

In particular, the hydraulic cylinder (C) is connected to the drive roll reduction control system (7) for determining and controlling to what extent the drive roll (5) to be pressed down.

Further, the drive roll reduction control system 7 is connected to a mold width variable control system 6 for detecting and controlling width variable information (variable width, variable speed, etc.) of the mold 2.

In addition, the drive roll reduction control system 7 is also connected to the drive roll speed control system 8 for controlling the speed of the drive roll 5 is configured to send information about the casting speed.

Referring to Figures 2 and 3 drive roller reduction control method when the width of the casting variable of the present invention through the equipment consisting of such a configuration as follows.

First, when the width of the mold 2 is started during casting, the mold width variable control system 6 periodically transmits the mold width to the driving roll reduction control system 7.

At this time, the cycle is different depending on the setting by the operator, but the cycle or time can be specified according to the characteristics of each continuous casting machine, the steel type, thickness, length.

At the same time, the drive roll reduction control system 7 periodically receives the casting speed from the drive roll speed control system 8 to make the slab width X to Y for the inclined slab length L as shown in FIG. It is calculated as shown in Table 1 and stored in memory.

Time (cycle) Length of inclined cast steel Width of cast steel 0 ... t 0 ... L X ... Y

Subsequently, the driving roll reduction control system 7 continuously tracks the inclined cast pieces to search for entry into the position of each driving roll 5.

When the inclined cast piece arrives at each driving roll 5 during the search, the driving roll reduction force calculated by Equation 1 below from the corresponding period, the inclined slab length, and the width of the slab is changed accordingly. Control.

This enables smoother and more standardized width variations.

For example, when the slab width Z is larger than X and smaller than Y, the driving roll reduction force is as follows.

Here, X 'is the driving force reduction force when the slab width is X, and Y' is the driving roll reduction force when the slab width is Y.

As described in detail above, the present invention improves the surface quality and improves the surface quality of the cast by accurately controlling the rolling force of the inclined cast using the position information of the mold short side when changing the width of the mold short side during casting in the continuous casting facility. There is an effect that can control the casting speed.

Claims (2)

In the method of controlling the reduction force in a continuous casting facility having a mold and a cast drive roll that serves to push down the mold and the cast piece that can vary the width during casting, A first step of capturing the width change start time and receiving the mold width information through the driving roll reduction control system; A second step of calculating the length of the inclined cast piece by receiving the casting speed from the drive roll speed control system simultaneously with the first step; A third step of periodically storing the width of the slab in a memory device according to the length of the inclined slab; The fourth step of controlling the pressing force of the drive roll by calculating the exact pressing force for the width of the cast steel while tracking the movement of the inclined cast steel in the strand after the third step Driving roll reduction control method when the width is changed. The method of claim 1, The driving force reduction control method during the variable width during casting, characterized in that the pressing force controlled in the fourth step is calculated by the following formula. (expression) (In this case, the driving roll reduction force is a case where the slab width Z is larger than X and smaller than Y, X 'is the driving force reduction force when the slab width is X, and Y' is the driving roll reduction when the slab width is Y. Power)