JP3117352B2 - Casting speed control method for belt type continuous casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt type continuous casting apparatus, and more particularly to a method for controlling a casting speed in the operation of a belt type continuous casting apparatus having an unsolidified rolling reduction device.

[0002]

2. Description of the Related Art FIG. 3 is a side view of a belt-type continuous casting apparatus provided with an unsolidified rolling-down apparatus. An operation control method of the apparatus which has been generally considered conventionally will be described. In FIG. 3, a belt-type continuous casting facility includes a metal belt 2 that circulates around a plurality of rolls 1 that are opposed to each other with a parallel gap, and an illustration that circulates around the gap end of the belt 2. Belt circulating mold 3 with a cooling device and a belt circulating mold 3 comprising a short piece block connected body
Has an unsolidified rolling device 5 having a plurality of roll pairs 4 provided continuously in the lower part of the device.

A guide roll 6 and a pinch roll 7
A pouring nozzle 11 with a flow rate adjusting nozzle 10 connected to a tundish 9 for injecting molten steel 8 into the belt circulation mold 3, and a sensor for detecting the level of the molten metal inside the belt circulation mold 3. 12 and a flow rate adjusting nozzle 10 so as to maintain the level of the molten metal at a predetermined position in accordance with the detected level of the molten metal.
And a drive unit 14 for circulating the belt and a drive unit 15 for the pinch roll 7 which are driven in association with each other at a constant speed.

The molten steel 8 injected into the belt circulation mold 3 maintained at the gap width (thickness of the slab 8a) t ₁ is cooled by water cooling while being sent downward in the belt circulation to form solidified shells on both sides. Then, while leaving a sufficient unsolidified portion inside, it enters into the unsolidified drafting unit 5 where it is pressed and formed into a slab 8a having a sheet thickness t, pulled out along the guide roll 6 by the pinch roll 7, and then downstream. To a finishing mill.

[0005]

In the equipment described above, the thickness of the slab before unsolidification reduction is t ₁ , the thickness of the slab after reduction is t,
When operating at a constant casting speed v ₁ , the molten steel 8 rises sharply due to a decrease in the slab thickness due to the reduction from the unsolidified reduction device 5.
Must be adjusted.

[0006] However, depending on the magnitude of the rolling down amount at this time, it may exceed the proper control range of the pouring nozzle 11 (the proper use range of the pouring amount per fixed time). If the flow exceeds the proper control range of the pouring nozzle 11, the flow of the molten steel becomes uneven, which adversely affects the quality of the slab. Further, even when the molten metal 8 can be used within the appropriate control range of the pouring nozzle 11, when controlling the opening of the flow rate adjusting nozzle 10, the molten metal surface of the molten steel 8 is stabilized due to the problem of follow-up of feedback control, especially during high-speed casting. There is a problem that it is difficult to cast in a state where it is cast.

SUMMARY OF THE INVENTION The present invention is directed to a belt-type continuous casting facility which can reduce the fluctuation of the molten metal level during casting and can stably control the level of the molten metal level within a proper use range of the pouring amount. It is an object of the present invention to provide a casting speed control method.

[0008]

According to the present invention, there is provided a slab having an unsolidified portion therein.
In a belt-type continuous casting facility provided with an unsolidified rolling reduction device, a rolling control unit and a casting speed are provided to the unsolidified rolling reduction device.
A degree control unit is provided, and the casting speed control unit increases and decreases the casting speed in proportion to the reduction amount of the slab by the reduction control unit simultaneously with the start of the reduction of the slab . In the rolling release, if the casting speed is lowered in accordance with the rolling reduction at the same time as the rolling release, the control range of the pouring nozzle can be secured.

[0009]

According to the present invention, as described above, the casting speed is increased or decreased in proportion to the amount of reduction by the unsolidified reduction device. Since the slab thickness is inversely proportional to the reduction amount, the slab thickness of the belt circulation mold part before unsolidification reduction is t ₁ , the slab feed speed at that time is v ₁ ,
The slab thickness after the start of reduction is t, and the slab feed speed at that time is v
Then, when the reduction of the slab is started, the casting speed v ₁ becomes v (ie, v) in inverse proportion to the slab thickness (t ₁ / t).
= (T ₁ / t) × v ₁ ). As a result, the decrease in the pouring amount due to the start of the reduction is offset by the increase in the casting speed.

[0010] Even if a slight change in the level of the molten metal occurs due to a delay in following, etc., the fluctuation is detected by the level-of-fluid level detection sensor. The flow control nozzle opening of the pouring nozzle is smoothly, easily and accurately adjusted within an appropriate control range.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the apparatus shown in FIG. 1 and the operation flow chart shown in FIG. FIG. 1 is a side view of a schematic configuration of a belt-type continuous casting facility for carrying out the method of the present invention. In the figure, the same elements as in the prior art are shown in FIG.
The same reference numerals are used, and duplicate description is omitted.

In FIG. 1, reference numeral 20 denotes a reduction control unit of the uncoagulating reduction device 5; 21 receives a reduction amount signal and a reduction on or off signal from the reduction control unit 20; And the casting speed v ₁ before rolling of the drive device 15 for the pinch roll 7 is controlled to rise to a casting speed v = (t ₁ / t) × v ₁ according to the rolling reduction (t ₁ −t),
The speed v during the reduction is reduced by the reduction-off signal to the speed v before the reduction.
_{This is} a casting speed control unit that controls deceleration to ₁ or controls the casting operation to stop at a certain time after pouring is stopped.

The unsolidified drafting device 5 supports a drafting frame 5a equipped with a plurality of drafting roll pairs 4 so as to be able to swing oppositely by a fixed support shaft 5b on the same axis as the uppermost drafting roll pair. A universal nut 5c supported on the side plate 5a, and a reverse ball screw 5 screwed to the universal nut 5c
d, and a rotary drive motor 5e for the reverse ball screw 5d. The drive control unit 20 drives the drive motor 5e to move the left and right reduction frames 5a in opposition as indicated by an arrow 5f to reduce the required reduction amount. I'm trying to get. For the other parts, the conventional configuration shown in FIG. 3 may be used as it is.

FIG. 2 is an operation flow chart of the casting speed control method of the present invention performed using the apparatus of FIG. Less than,
The procedure of the method of the present invention will be described with reference to FIGS.
The line of the apparatus shown in FIG. 1 is activated, and the belt 1 and the pinch roll 7 of the belt circulation mold 3 start feeding and driving. At this time, the line is driven at a speed v ₁ set so that solidified shells can be formed on both sides of the molten steel 8 in the belt circulation mold 3. When the pouring is started and a predetermined casting time is reached, the unsolidified drafting device 5 starts rolling down by a signal of the drafting control unit 20, and at the same time, the casting speed control unit 21 works in conjunction with the belt circulation type mold according to the drafting amount. The feed speed of the third set and the pinch roll 7 is increased. That is, here, the belt circulation mold 3
The slab 8a having a thickness of t ₁ sent out from the section is reduced to a thickness t by a reduction amount (t ₁ -t) set in the reduction control section 20 through a plurality of roll pairs 4 and simultaneously a casting speed control. The section 21 adjusts the line feed speed v according to the reduction amount (t ₁ -t).
₁ is increased to v = (t ₁ / t) × v ₁ .

By making these two controls parallel,
The decrease in the pouring amount due to the reduction of the slab is offset by the increase in the casting speed, and the rapid rise in the molten metal level in the belt circulation mold 3 is eliminated. Normal level fluctuations and small level fluctuations due to the responsiveness of the above control are detected by the level detecting device 12, and the opening of the flow rate adjusting nozzle 10 is closed or closed by feedback control by the nozzle opening controller 13. Adjust to open,
The casting surface is kept constant, and the casting operation is continued.

When a signal of the completion of reduction is input during operation,
Unsolidified rolling device 5 opens the pressure by the pressure control unit 20, the casting speed controller 21 slows down the feeding speed of the casting line from _{v = (t 1 / t)} × v 1 to v ₁ in conjunction this .

According to such a method, a sudden change in the molten metal level in the belt circulating mold 3 due to the reduction of the casting slab 8a generated and sent out by the belt circulating mold 3 is eliminated, and the molten metal level hardly fluctuates. It can be controlled within the proper use range of the nozzle pouring amount without using. As a result, the level control of the molten metal can be easily and stably performed, and a slab of stable quality can be obtained.

[0018]

In summary, the present invention is characterized by the fact that
In a belt-type continuous casting equipment equipped with an unsolidified rolling reduction device for rolling down a slab having a portion, the unsolidified rolling reduction device is pressed by the unsolidified rolling reduction device.
A lower control unit and a casting speed control unit are provided;
Increases the casting speed in proportion to the amount of reduction of the slab by the reduction control unit simultaneously with the start of the reduction of the slab, while reducing the casting speed simultaneously with the start of the reduction release, so that the pouring valve can be used properly. In this case, it is possible to control the molten metal level easily and stably, and to obtain a stable cast slab quality.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a belt-type continuous casting facility for carrying out a method of the present invention.

FIG. 2 is an operation flowchart of a casting speed control method of the present invention, which is performed by the apparatus of FIG.

FIG. 3 is a side view of a belt-type continuous casting facility showing a conventional operation method.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Touring roll 2 Metal belt 3 Belt circulation mold 4 Rolling roll 5 Unsolidified rolling device 6 Guide roll 7 Pinch roll 8 Molten steel 8a Cast slab 9 Tundish 10 Flow control nozzle 11 Pouring nozzle 12 Metal level detection sensor 13 Nozzle opening degree control unit 14 Drive device for belt patrol 15 Drive device for pinch rolls 20 Reduction control unit 21 Casting speed control unit t ₁ Slab thickness before reduction t Slab thickness after reduction v ₁ Casting before reduction v Casting before reduction Single feed speed v = (t ₁ / t) × v ₁ Slab feed speed after reduction

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-64754 (JP, A) JP-A-3-66457 (JP, A) JP-A-62-6740 (JP, A) JP-A 61-64 232045 (JP, A) JP 4747212 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 11/06 340 B22D 11/128 350 B22D 11/20 B22D 11 / Ten

Claims (1)

(57) [Claims] 1. A slab having an unsolidified portion therein is reduced.
That the unsolidified rolling apparatus belt continuous casting plant equipped with the casting speed controller reduction control unit to unsolidified rolling device
Wherein the casting speed control unit increases or decreases the casting speed in proportion to the amount of reduction of the slab by the reduction control unit .