JPS5916545B2 - Method for detecting slab position in continuous casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous casting apparatus, and particularly to a method for detecting and controlling the position of a slab.

One of the biggest reasons why the continuous casting method has rapidly increased in place of the conventional ingot making and shunting methods is the reduction in manufacturing costs due to improved yield.

Therefore, in the continuous casting method, it is necessary to appropriately distribute the product to the slab material.

This distribution is normally done based on the amount of molten steel for one cider (hereinafter referred to as a charge), but the slab that is cast into the mold via the tundish is continuous, and the position of the charge unit can be detected. It is impossible to measure directly.

For this reason, as is well known, at present, a detection roll attached to a pinch roll or the like is brought into contact with the slab, and the position is indirectly detected from the count value of a pulse generator within the detection roll.

The biggest drawback of this method is that the position detection is often inaccurate due to the slippage that occurs between the detection roll and the slab, resulting in uneven product distribution and the expected yield. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method for detecting and controlling the position of a cast slab, which enables accurate cutting control with high yield by detecting the accurate position of the cast slab.

A feature of the present invention is that a measuring device for measuring the length of the slab with high precision is installed in the downstream process of the cutter, and the length of the slab currently being cast can be determined from the length of the cut slab measured by the measuring device. The point is to correct the position of the charge unit.

Embodiments of the invention will be described below with reference to the drawings.

FIG. 1 shows an overview of continuous casting equipment and an overview of the present invention.

The casting length is counted from a detection roll 5 in contact with the slab 4 by a pulse generator 8 housed therein.

These detection rolls 5 are provided near the pinch roll 20 and the measure roll 21, and are counted independently at each point.

These pulse count values are different due to the difference in the roll diameter of each detection roll and the difference in temperature of the slab at the detection location.
Engineering value conversion and hot correction are performed in the casting length calculator 9,
The signals are integrated and sent to the central processing unit 12.

The central processing unit 12 determines the casting of each charge based on the signal from the casting control device 10 that controls the opening and closing of the nozzle of the ladle 1 and the nozzle of the tundish 2 and the casting length signal sent from the casting length calculator 9. The charge length is calculated and the positions of the leading and trailing ends of the charge are detected.

The central processing unit 12 determines an appropriate slab cutting length with a good yield based on the information regarding the positions of these charges and a separately determined product cutting method, and outputs it to the cutting control device 11.

3 is a mold, and 7 is a photosensor.

The length of the slab cut by the cutting machine 6 is precisely measured by a slab measuring device 13, and the information is fed back to the central processing unit.

゛The central processing unit 12 calculates the deviation δl between the slab cutting length #OUT outputted to the cutting control device 11 and the cutting length "'OUT detected by the casting measuring device 13, and determines the deviation δl between the cutting length #'OUT outputted to the cutting control device 11 and the casting of the uncut charge. length (hereinafter referred to as uncut casting length and δ11” l
1cuT 11'OUT+ ==・(1) Call) is modified.

FIG. 2 shows details of the slab measuring device 13.

The slab measuring device is located in the torch exit zone 17 and the unloading zone 19.
(this is called a measurement zone), and a group of photosensors 14 is provided within this zone.

This measurement zone 18 is provided at a location separated by light from the cutting device 6 in order to avoid the influence of melted pieces etc. during cutting.

A plurality of photo sensor units 14 are installed within this zone to detect the position of the slab.

The photosensor unit 14 includes a plurality of photosensors 7
The moving speed of the slab at the time of application of each unit is determined from the ON/OFF status of each sensor and its timing.

15 is a slab after cutting, and 16 is a delivery roll.

Now, if the interval between units i and j is lij, the moving speed of each unit is V i' + V J, and the timing difference between units i and j is T, then the slab length esL
B is 18LB(1j)-lI J + I□ vd, t#l
i j + (v1 + v) - (2).

(Always arrange the units so that the condition of 1SLB > lij is satisfied.) Since the actual measurement values are averaged over N sets of units in the zone, the slab length obtained by equation (2) is extremely accurate. It will be good.

FIG. 3 shows a method of correcting the pulse count value of the charge currently being poured using the cut slab length 1, sLB described above.

Now, when a slab with charge N is cut, the casting length currently being counted is 3'P, and the casting length of charges i, j, etc., which have already been cast is 4., l.・・・・・・
・If the uncut casting length of charge N is 1 ms and the machine length of the strand is ls, then the following relationship holds true.

lp+Σ16 + li m == ls""song'(3
)1m-IN-Σl SLB ・・・・・・
...(4) N: Number of cast charges in progress on the strand M: Number of cut slabs of the Nth charge IP is the true value of l'P, Δl 2l l p - l' p +...
There is the following relationship (5).

As lP>l'P, from (3), (4), and (5), Δg-*P-e'P-Σli+Σ1sLB-(6
), and the correction amount Δl is obtained.

Here, ls is a fixed length, l'P is a known quantity, and LsLm' has already been measured! li is the corrected casting length.

Moreover, at the time of the first correction, the following equation is obtained.

Δli= (i, -Jli-mine・li/l 5(6
)'(6), (6)' From the formula, the pulse count value of the charge during casting depends only on the measurement accuracy of the sum of the lengths of the cut slabs of the charge that is already being cut, which is 118LB.

In other words, formula (6) is based on the principle that the amount of molten steel poured from the mold is equal to the amount of slab cut by the cutting machine, and the length of the currently poured slab is calculated from the accurately measured length of the slab after cutting. In other words, the position of the tip of the charge is accurately detected.

In this way, in the present invention, the pulse count value is corrected every time the slab is cut, so the accuracy is extremely high.
Furthermore, since there is no need to consider the error in the uncut portion IT after the cutting machine shown in FIG. 4, this is a very effective method.

(Conventionally, when trying to increase the positive value only when determining the casting length, it was difficult to handle the error in 'IT', and a sufficient effect could not be obtained.

)

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram illustrating the outline of the continuous casting equipment and the control system according to the present invention, Fig. 2 is a diagram illustrating details of the slab measuring device, Fig. 3 is a diagram illustrating details of the slab measuring device, Figure 4 is a diagram illustrating the casting length correction method, 4... Slab, 8... Pulse generator, 12... Central processing unit, 13... ...
Slab measuring device, 7...Photo sensor.

Claims (1)

[Claims] 1. In a continuous casting device, the length of the slab after cutting is measured on the exit side of a cutting machine installed on the exit side of the casting device, and the measured slab length is detected by a slab movement detection roll. 1. A method for detecting a slab position in a continuous casting apparatus, comprising: correcting a cast slab position signal that has been corrected, and detecting a slab position from the corrected position signal. 2. The method for detecting the position of a slab in a continuous casting apparatus according to claim 1, characterized in that the position signal detected from the detection roll is corrected every time the slab is cut.