JPH01293962A - Control method for drawing cast billet of continuous casting device - Google Patents

Abstract

PURPOSE:To prevent the bend of a cast billet and the generation of the surface flaw by providing a detector measuring the gap of a cast billet and guide plate on a sliding guide plate and adjusting the cast billet drawing speed of a correction part based on the difference in a observed gap value and set gap value. CONSTITUTION:A contact type or noncontact type detector 15 for the gap between a cast billet S and guide plate 7 is arranged at the center part in the longitudinal direction of a curving slide guide plate 7 and connected to a straightening roll speed control device 16. In this case, the optimum gap value between the cast billet S and guide plate 7 is set in advance on the control device 16. When the observed gap value fed from the detector 15 is input to the control device 16, the device 16 adjusts the drawing speed of a straightening roll 8 by a comparing the observed value with set value and making it coincident with a set roll speed. The contact of the cast billet S and guide plate 7 is surely restrained and the generation of the bend and surface flaw of the cast billet is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Industrial Field of Application The present invention relates to a method for controlling slab withdrawal in a vertically curved continuous casting apparatus having a vertical mold directly below the mold and a curved portion below the mold.

[Conventional technology]

FIG. 2 shows a schematic diagram for implementing the conventional method. (1) is a mold for forming a slab (S) from molten steel, and below it is a water-cooled cooling zone (2) for cooling the hot slab (S). Solidification proceeds toward the inside of (S). A pinch roll (3) is provided at a position where the slab (S) has solidified to a certain extent,
The slab (S) is vertically pulled out by the pinch rolls (3) according to a preset drawing speed to form the vertical part (4) of the continuous casting apparatus.

A bending roll (
5), this bending roll (5) applies pressure to the slab (S), and the slab (S) is bent in the direction of the compression, so that the slab (S) is bent at approximately 90 degrees. It is curved to form a horizontally oriented curved part (6) of the continuous casting device.

Place the straightening roll (8) in a position where the slab (S) faces horizontally.
A straightening section is provided in which the curvature of the slab (S) is corrected and the slab (S) is made straight.

A cutting torch is provided behind the straightening section (9), where the material is cut into a predetermined length into slabs, billets, etc. Further, a sliding guide plate (7) is provided at a position outside the back surface of the section (S) of the curved portion (6) to prevent abnormal outward curving of the slab (S). In addition, the sliding guide plate (
2) is provided on the back and side parts of the curved slab (S), but not on the inside part.

In this method of controlling slab drawing of a vertically curved continuous casting device, the pinch roll (3) to be controlled by the pinch roll speed controller 0δ is based on the drawing speed set value preset in the drawing speed setting device 0υ. For example, the drive device of the pinch roll (3) is controlled in speed (voltage) corresponding to the rotation speed so as to have a predetermined rotation speed, and the pulling speed setting device Qll is also controlled for the straightening roll (8). Based on the preset pulling speed setting value, the straightening roll speed control device OJ controls the straightening roll (for example, voltage control) so that the speed is the same as the pulling speed of the pinch roll (3), similarly to the pinch roll speed control device aZ. 8) is applied to the drive device.

In such slab drawing control, the pinch roll (
There is a slight difference between the slab pulling speed of step 3) and the slab pulling speed of the straightening roll (8), and when this tiny difference accumulates, the curved portion between the pinch roll (3) and the straightening roll (8) 6
) compressive or tensile force acts on the slab (S), causing the slab (S) to curve inward or outward as shown by the dotted line in Figure 1. cause an abnormality. For this purpose, a worker goes around the continuous casting equipment and determines whether the gap between the sliding guide plate (7) and the slab (S) is normal or abnormal, and if it is determined to be abnormal, finely adjust the speed of the straightening roll. The device 041 is operated to correct the drawing speed of the slab (S) to the straightening roll (8) via the straightening roll speed control device 03, so that the slab (S) is normally drawn along the sliding guide plate (7). (S)
I've kept it to 71 songs.

By the way, even though the pulling speed of the pinch roll (3) and the pulling speed of the straightening roll (8) are controlled to be the same, the reason why there is a difference in the pulling speed between the two is as follows: ■ Pinch roll (3) and the speed control error of the straightening roll (8); ■) the pinch roll (3) and the straightening roll (8) due to position changes due to load fluctuations of the bending roll (5);
) Due to load fluctuations, there is a speed difference between the two rolls, ■ Pinch rolls (3
) and the occurrence of a speed difference between the two rolls due to load fluctuations on the straightening roll (8).

[Problem to be solved by the invention]

In the above conventional technology, an error occurs in the respective drawing speeds of the pinch roll (3) and the straightening roll (8), and this error in the drawing speed causes bending or surface flaws in the product slab. In order to prevent the sliding guide plate (2) from being worn out due to contact with the slab (S), and furthermore, to prevent the above-mentioned troubles, workers should monitor the degree of curvature of the slab (S) and take precautions to prevent curvature. The speed of the straightening roll had to be finely adjusted depending on the degree of damage. Particularly, continuous casting equipment is large-sized, with a radius of about 10 meters for the curved portion alone, and the atmosphere is high, making monitoring the workers a difficult task. In addition, the judgment of the degree of curvature by each worker was different, and the fine adjustment was not constant, so it could not be said that the operation was always performed at a well-adjusted drawing speed, which caused problems such as the quality of slabs.

[Failure to solve the problem]

The present invention provides a sliding guide plate provided on a curved part continuing below the vertical part, and a gap detector for measuring the gap between the sliding guide plate and the slab to be pulled out, and the actual measured gap from the gap detector. A method for controlling slab withdrawal in a continuous casting machine, characterized by comparing the gap value with a predetermined set gap value and adjusting the slab withdrawal speed of a straightening section following a curved section according to the difference. .

〔Example〕 An embodiment of the present invention will be described based on FIG.

FIG. 1 is a schematic diagram for implementing the present invention, and FIG.
Same as in the figure - Equipment is given the same reference numerals. In the control method of the present invention, a gap detector 09 is newly provided in the longitudinal center of the curved sliding guide plate (7), and the signal from the gap detector 09 is input to the straightening roll speed control device OG. be done.

The straightening roll speed control device 0e does not receive a signal from the conventional straightening roll speed fine adjuster 0Φ.

The straightening roll speed control device Oe is equipped with a slab (S) in advance.
An appropriate gap value between the slide guide plate (7) and the sliding guide plate (7) is input as the set gap value. Compare this set gap value with the actual value from the gap detector 09, and if they are the same,
Based on the signal from the pulling speed setting device (II), it is calculated whether the pinch roll speed controller 0211 straightening "1" and the straightening roll speed controller Oυ have the same speed value, and according to this calculated value, the pinch roll (3) and the straightening roll When the slab (S) is pulled out at the same speed as (8), and the actual value is larger than the set gap value, the pulling speed of the straightening roll (8) is higher than the pulling speed of the slab (S) of the pinch roll (3). is faster, and in the straightening roll speed control device θG, the straightening [7
- Pulling speed setting device 0υ to reduce the speed of the lever (8)
On the other hand, if the actual value is smaller than the set gap value, the signal from the drawing speed setting device O1) is limited to increase the speed of the straightening roll (8), so that the actual gap value is always maintained. or a preset gap value. Note that the gap detector 09 used in the present invention
This may be a contact type as shown in FIG. 3 or a non-contact type using ultrasonic waves or laser. In addition, in Fig. 3, (21) is a touch roller that rotates while not contacting the slab, and is freely attached to the tip of an arm, and a weight (22) is fixed to the other end of the arm. An upward force is applied to the touch roller (21) using the support shaft (23) at the center of the arm as a fulcrum, and a vertical detection rod ( 24), and a displacement sensor (25) is attached to the lower end of the detection rod (24) to detect the degree of downward movement of the detection rod (24). A touch roller (2) follows the distance movement of the slab (S) from the sliding guide plate (7).
Along with the vertical movement of step 1), the detection rod moves downward, and the extent of this vertical movement is detected by the displacement sensor (25) and the slab (S) is detected.
The gap between the sliding guide plate (7) and the sliding guide plate (7) is detected.

〔Effect of the invention〕

According to the slab drawing control method of the present invention, since the slab pulling speed by the straightening roll is controlled so that the gap between the sliding guide plate and the slab is always constant, the slab does not slide. Avoid contact with the guide plate (therefore, prevent the product slab from bending, prevent flaws from forming on the slab surface, prevent the sliding guide plate from wearing out, and prevent overload from occurring between the pinch roll and straightening roll. This provides various effects such as preventing the continuous casting equipment from stopping due to

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram shown for detailed explanation of the present invention,
FIG. 2 is a schematic diagram showing a conventional example, and FIG. 3 is a schematic diagram showing an example of a gap detector used to implement the present invention. 3... Pinch roll 4... Vertical section 6 - Curved section 7... Sliding guide plate 8 - Straightening roll
9... Straightening part 15/Gap detector S... Slab

Claims (1)

[Claims] In a slab drawing control method for a vertically curved continuous casting device,
A gap detector for measuring the gap between the sliding guide plate and the slab to be pulled out is installed on the sliding guide plate provided on the curved section continuing below the vertical section, and the actual gap value from the gap detector is determined in advance. A method for controlling slab withdrawal for a continuous casting apparatus, characterized in that the slab withdrawal speed of a straightening section following a curved section is adjusted in accordance with the difference between the set gap value and the set gap value.