JP3067916B2 - Flow controller for molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow driving device for stirring molten metal in a mold, and more particularly, but not exclusively, to moving a molten metal in a continuous casting mold horizontally along the side of the mold. The present invention relates to a flow control device that drives in a direction and brakes in a place where a flow velocity is large.

[0002]

2. Description of the Related Art In continuous casting, for example, molten steel is poured into a mold from a tundish, and the molten steel is drawn from the mold wall while being gradually cooled. If the temperatures on the mold wall surfaces at the same height are not uniform, surface cracks and shell ruptures are likely to occur. In order to improve this, conventionally, a molten steel is circulated and flown along the wall of the mold parallel to the upper surface thereof using an electromagnet or a linear motor (for example, Japanese Patent Application Laid-Open No. 1-228645). If the flow velocity of the molten steel in the surface layer of the molten steel is not uniform, the powder on the molten steel is caught in the molten steel and this becomes a defect in the steel slab. Is supplied, and the speed at which the molten steel flows into the mold is high, which tends to cause powder entrainment. To improve this, Japanese Patent Application Laid-Open No. 3-258442 discloses an electromagnetic brake device for applying a static magnetic field to molten steel.

[0003]

Problems to be Solved by the Invention
Although the flow drive of molten steel disclosed in Japanese Patent No. 5 has some effect, the flow of molten steel flowing into the tundish via the injection nozzle disrupts the circulating flow along the mold wall. An electromagnetic brake disclosed in Japanese Patent Application Laid-Open No. 3-258442.
The key device has the effect of suppressing the flow of molten steel flowing into the tundish through the injection nozzle, but has a low effect of making the flow velocity distribution uniform.

An object of the present invention is to flow and drive a molten metal and to make the flow velocity more uniform.

[0005]

According to a first aspect of the present invention, there is provided a flow control device, wherein m ≧ 3 and n ≧ 1 arranged along a mold side (1) surrounding a molten metal. , ... m-th
× n magnetic poles (11 to 19); first, second,..., M × n electric coils (1Aa, 1B) for exciting each of these magnetic poles
a, 1Ca, 2Aa, 2Ba, 2Ca, 3Aa, 3Ba, 3Ca); signal generating means (81 to 83) for generating m-sequence signals for forming a linear drive AC current waveform (Aa, Ba, Ca); The first series of signals (corresponding to Aa)
m + 1, 2m + 1,... Amplifying means (612) for amplifying at an amplification factor (output of 611) addressed to each of the electric coils (1Aa, 2Aa, 3Aa), and an output signal of the amplifying means (612). Means (614) for biasing by a bias value (output of 613) addressed to each, and first, m + 1, 2m + 1,... For energizing each of the electric coils at an energizing duty corresponding to the biased signal. Coil driver (61,
64,67, 615-621; 41,44,47, 411-414); 2nd signal
(Ba compatible) is the second, m + 2, 2m + 2, ... electric coil
(1Ba, 2Ba, 3Ba) Amplifying means for amplifying at the amplification rate addressed to each, means for biasing the output signal of the amplifying means by the bias value addressed to each of these electric coils, and corresponding to the biased signal Second, m + 2, 2m + for energizing each of the electric coils with the energizing duty
2, ... Coil driver (615-621 of 62,65,68; 42,45,
48, 411 to 414); the third series of signals (corresponding to Ca)
3m,... Amplifying means for amplifying at the amplification rates respectively assigned to the electric coils (1Ca, 2Ca, 3Ca), means for biasing an output signal of the amplifying means by a bias value addressed to each of these electric coils, and M, 2m, 3m,... Coil driver (63, 66, 69-6) for energizing each of the electric coils with the energization duty corresponding to the biased signal
15-621; 43, 46, 49, 411-414).

The flow control device according to the second aspect of the present invention comprises first, second,..., M × n magnetic poles (11 to 19) arranged along a mold side (1) surrounding a molten metal; 1st, 2nd,... M × n electric coils (1Aa, 1Ba, 1Ca, 2Aa, 2Ba, 2Ca, 3Aa, 3Ba, 3Ca) for exciting each magnetic pole of Memory means (812 of 81-83) storing current-carrying duty data for forming the data; sequentially updating the read addresses of the memory means (812 of 81-83) at a predetermined cycle Tpa; Means for reading m-three (three stations: corresponding to each of Aa, Ba, Ca) energization duty data, each of which is pre-determined by a predetermined phase with respect to waveform (Aa); −
Multiplying means (61, 64, 67, 612) for multiplying the data by the amplification factors respectively assigned to the first, m + 1, 2m + 1,... Electric coils (1Aa, 2Aa, 3Aa); An adding means (614 of 61, 64, 67) for applying a bias value addressed to each of these electric coils, energizing each of these electric coils for a time indicated by the sum obtained by the adding means within a predetermined period Tpa. 1st, m + 1, 2m + 1,..., Coil driver (617 to 621 of 61, 64, 67; 411 to 414 of 41, 44, 47); -The second m
+2, 2m + 2,..., Multiplication means (62, 65, 68) for multiplying the amplification factors addressed to the respective electric coils (1Ba, 2Ba, 3Ba)
612), and adding means (61 of 62, 65, 68) for adding a bias value addressed to each of these electric coils to the obtained product.
4) The second and mth currents to be supplied to each of these electric coils for the time indicated by the sum obtained by the adding means within the predetermined period Tpa
+2, 2m + 2, ... coil driver (617 of 62, 65, 68)
621; 42, 45, 48, 411 to 414); The m-th, 2m, 3m,...
Multiplying means (63, 66, 69, 612) for multiplying the amplification factors addressed to the respective electric coils (1Ca, 2Ca, 3Ca), and adding the bias values addressed to the respective electric coils to the obtained product; Adding means (614 of 63, 66, 69) within a predetermined period Tpa,
The m-th, 2m, 3m,... Coil drivers (617 to 621 of 63, 66, 69; 411 of 43, 46, 49) that energize each of these electric coils for the time indicated by the sum obtained by the adding means. 414);

[0007] The symbols and the like shown in the parentheses indicate the reference numerals or corresponding items of the corresponding elements in the embodiments described later for reference.

[0008]

According to the molten metal flow control device of the present invention, a plurality of magnetic poles arranged along the mold side (1) surrounding the molten metal are provided.
A plurality of electric coils (1Aa to 3Aa, 1Ba to 3Ba, 1Ca to 3Ca) for exciting each of
~ 83; 61 to 69, 611, 612, 615 to 621; 41 to 49) are energized with a linear drive AC current (Iaa: Aa, Ba, Ca) for flowing and driving the molten metal in the arrangement direction of the magnetic poles, and , DC bias means
(61, 69, 613, 614, 615 to 621; 41 to 49) supply a braking direct current (Ib) for braking the molten metal.

[0009] The molten metal by the alternating current of the electric coil,
It is driven to flow in the direction in which the magnetic poles are arranged, and is braked by direct current. That is, the same electric coil is shared for the flow drive and the braking. Therefore, the flow driving can flow the molten steel to remove the blowhole on the solidified surface of the molten steel, and also suppress the flow velocity of the injected molten steel by braking to facilitate the floating of inclusions (for example, powder). Can be In this way, the same electric coil can perform flow driving for suppressing or removing the blowhole and braking for suppressing inclusion of inclusions and promoting levitation.

[0010] driving force setting means (611, 612 of 61 to 69) is set to each electrical coil of the linear driving force, braking force setting means
(613, 614 of 61-69) determine the braking force of each electric coil, and a plurality of AC biasing means (81-83; 61-69, 615-62).
1; 41 to 49) is an alternating current (Ia) for generating a linear driving force determined by the driving force setting means in each of the electric coils.
a: Aa, Ba, Ca), and a plurality of DC biasing means (61
To 69, 615 to 621; 41 to 49) supply a DC current (Ib) to each electric coil to generate a braking force determined by the braking force setting means. That is, for each electric coil, an alternating current and a direct current for generating a flow driving force and a braking force directed thereto are applied.

For example, as shown in FIG. 1, when the molten steel injection nozzle 30 is located at the center of a rectangular space surrounded by the mold sides 1 to 4, the molten steel in the mold is generally represented by a solid arrow in FIG. In the direction shown, the molten steel flow is non-uniform in the horizontal direction of the long side 1, and the flow velocity is too high immediately in the vicinity of the nozzle 30 and slow in the distance. In this case, an alternating current and a direct current that generate a strong flow driving force and a weak braking force are applied to the electric coil immediately adjacent to the nozzle, whereby the blowhole on the solidified surface of the molten steel is removed and its generation is suppressed. You. Driving force setting means (611,612 of 61-69) and braking force setting means (61-69
613,614), the linear driving force and the braking force of each electric coil are set so that the flow rate of the molten steel in the horizontal direction of the long side 1 is uniform and in the same direction.
Over the entire length of the long side 1 in the horizontal direction, the effect of suppressing the blowhole and the effect of promoting the floating of inclusions are simultaneously provided.

Each electric coil has m phases (m = 3 in the embodiment).
The linear motor is energized by AC (for flow driving). In order to apply DC for braking to the motor, the energizing current value of the electric coil is determined by energizing duty control. The AC current waveform is obtained by a time-series change of the current-carrying duty and switching of the current-carrying polarity. By multiplying a series of current-carrying duties providing a basic AC waveform by an amplification factor, an AC waveform having an amplitude corresponding to a required flow driving force is obtained. Such amplitude adjustment or setting is performed by the multiplication means for each electric coil. For the braking DC component, an energizing duty (a constant value in time series) corresponding to the braking DC current value is added to the energizing duty for obtaining an AC current waveform for energizing the linear motor (this energizing duty). (Substantial subtraction if tee is negative)
By doing so, it is superimposed on the AC current waveform. By increasing / decreasing the energization duty, a DC component corresponding to a required braking force can be obtained. Such level (bias) adjustment or setting is performed by the adding means for each electric coil. In this embodiment, the alternating current having the desired amplitude for the flow drive, the direct current having the desired level for the braking, and the combination thereof are performed by the operation of the energization duty, and the electric coil energization circuit becomes extremely simple.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0014]

FIG. 1 shows an arrangement of magnetic poles and electric coils according to an embodiment of the present invention. In the drawing, 1 and 2 are long sides of the continuous casting mold, and 3 and 4 are short sides. In a space surrounded by these, molten steel is passed from the front side to the back side of the drawing of FIG. From above to below). In this embodiment, the molten steel in the molds (1 to 4) is
Three-phase linear motor type from right to left along long side 1 (+ y
In order to drive (in the direction from −y to −y), the first set of nine magnetic poles 11 to 19 is disposed outside the long side 1 in the horizontal direction (from + y to −y).
Direction). In addition, in order to drive from left to right (from −y to + y) along the long side 2, a second set of nine magnetic poles 21 to 29 is disposed outside the long side 2 in the horizontal direction (+
(in the direction from y to -y). One electric coil 1Aa or the like is wound around each of these magnetic poles. The magnetic pole bases 10 and 20, which are the common magnetic path between the magnetic poles,
They are connected by yokes 31 and 32 so as to suppress the leakage of the magnetic flux to the outside.

Referring to FIG. As shown in FIG. 2, the first set of first electric coils 1Aa wound around the first set of first magnetic poles 11 has a GTO (gate turn) for positive polarity conduction.
OFF / SCR) 411 and GTO 41 for negative polarity conduction
2 are connected to the + output terminal and the − output terminal of the DC power supply 60. GTOs 411 and 412 are G
On (energized) / off (non-energized) are energized by the TO drivers 413 and 414. The current detector 415 detects the value (absolute value) of the current flowing through the electric coil 1Aa, and supplies an analog signal indicating the detected value to the energizing pulse generator 61 described later. These energizing and detecting circuit elements and the electric coil 1A
The combination circuit a is the first excitation circuit 41.

The other electric coils 1Ab and the like are also connected to the same energization and detection circuit elements to form a similar excitation circuit 42 and the like. That is, as shown in FIG. 2, the first set of nine excitation circuits 41 to 49 and the second set of nine excitation circuits are provided for the first set of nine electric coils 1Aa and the like of FIG. 51 to 59 are configured.

Referring to FIG. FIG. 3 shows the overall configuration of the flow control circuit including the excitation circuits 41 to 49 and 51 to 59 shown in FIG. In FIG. 3, the power supply circuit is omitted, and the direction in which the control signal flows is indicated by an arrow. GTO drivers (411, 41) for the excitation circuits 41 to 49, 51 to 59
412) include energization pulse generators 61 to 69, 71 to 7
9 gives an ON instruction pulse (a high level H indicates an ON instruction / a low level L indicates an OFF instruction). FIG. 4 shows the configuration of the energizing pulse generator 61. Its function will be described later. Other energization pulse generators 62 and the like have the same configuration as 61.

The energizing pulse generators 61, 64 in the first set
To 67 and 67, a function generator 81 provides a series of energization duty data that produces a time-series current change in the form of an AC sine wave (for example, Aa in FIG. 7). A function generator 82 includes a series of energization duty data that causes a time-series current change in the form of an AC sine wave (eg, Ba in FIG. 7) for the energization pulse generators 62, 65 and 68 in the first set. give. A function generator 83 includes a series of energization duty data for generating a time-series current change in the form of an AC sine wave (for example, Ca in FIG. 7) for the energization pulse generators 63, 66 and 69 in the first set. give.

The energizing pulse generators 71, 74 in the second set
At 77 and 77, a function generator 84 provides a series of energization duty data which produces a time-series current change in the form of an AC sine wave (eg, Ab in FIG. 7). A function generator 85 includes a series of energization duty data that causes a time-series current change in the form of an AC sine wave (Bb in FIG. 7) for the energization pulse generators 72, 75 and 78 in the second set. give. A function generator 86 includes a series of energization duty data for generating a time-series current change in the form of an AC sine wave (for example, Cb in FIG. 7) for the energization pulse generators 73, 76 and 79 in the second set. give.

The structure of the function generator 81 is shown in FIG. Its function will be described later. Other function generators 82 to 86 have the same configuration as 81. The pulse generation circuit 90 includes a timing pulse for generating energization duty data for each series so as to produce a time-series current change in the form of an AC sine wave (for example, Aa to Ca and Ab to Cb in FIG. 7). A timing signal is generated and given to function generators 81-86.

Referring to FIG. 6, the pulses generated by pulse generating circuit 90 will be described. Assuming that the alternating current waveform for driving molten steel flow is Is shown in FIG.
Generates a clock pulse Pd having an extremely short cycle with respect to one cycle of the AC current waveform Is, and generates a clock pulse Pd
To generate an energization timing pulse Pa that also defines one cycle of the duty energization, which is also shorter than one cycle of Is, and divides the pulse Pa to obtain an AC current waveform Is. A first AC cycle synchronization pulse Pbo that defines one cycle is generated. The circuit 90 further counts the pulse Pa based on the pulse Pbo, and associates the Aa of FIG. 7 with the AC current waveform Is.
Second, third, fourth, fifth, and sixth AC periods for generating waveforms Ba, Ca, Ab, Bb, and Cb (FIG. 7) with a phase lag of 180 °, 180 °, 60 °, and 300 °. Synchronization pulses P _b120 , P _b240 , P _b180 , P _b60 and P
_{Generates b300} . These pulses are, as shown in FIG. 5, a function generator 81 to 86 and an energizing pulse generator 6.
1-69, 71-79.

The function of the function generator 81 will be described with reference to FIG. The memory 812 stores energization duty data (energization time data during one cycle of the pulse Pa) for energizing the electric coil with a current having a reference AC current waveform Is (FIG. 6) for flowing molten steel. And represents the number of clock pulses Pd) for one cycle of Is, and the absolute value of the value represented by the energization duty data in the first half cycle and the second half cycle is the same, but the energization in the first half cycle is performed. The duty data has a positive value in order to designate the positive polarity conduction, and the duty data in the second half cycle has a negative value in order to designate the negative polarity conduction. The first AC cycle synchronization pulse Pbo (high level H) clears the address counter 811. While the pulse signal Pbo is low level L, the address counter 811 counts up (rises) the energization timing pulse Pa. The count data of the address counter 811 specifies the read address of the memory 812. Thereby, the memory 812 synchronizes with the arrival of the pulse Pa (rise of Pa) to supply a series (1 of Is) for supplying the reference AC current waveform Is to the electric coil.
Cycle duty data) is sequentially output,
When the pulse Pbo arrives, a series of energizing dues are also performed.
The data is sequentially output. Output data of the memory 812
The latch 813 synchronizes with the pulse Pa (falling).
Is latched (stored).

The configuration of the function generators 82 to 86 is the same as the configuration of the function generator 81, but as shown in FIG. 5, the function generator 82 is supplied with a second AC periodic synchronizing pulse Pb _120, thereby Since the address counter (not shown) is cleared and the phase of Pb ₁₂₀ is delayed by 120 ° from Pbo, the current flowing through the electric coil based on the current duty data generated by the function generator 81 is reduced. For example, in the case of Aa in FIG.
The energizing current of the electric coil based on the data is Ba in FIG.
Becomes The function generator 83, since the third Thereby the address counter AC cycle synchronization pulses Pb ₂₄₀ is provided (not shown) is cleared, and Pb ₂₄₀ is P
Since the phase is delayed by 240 ° from bo, the function generator 8
The energizing current of the electric coil based on the energizing duty data generated by No. 3 is Ca in FIG. As will be described later, the Aa (81 output) of the current (waveform) flowing through the electric coil based on the energizing data output from these function generators 81 to 83 is the electric coil 1A shown in FIG.
a, 2Aa, and 3Aa, Ba (82 outputs) flows through the electric coils 1Ba, 2Ba, and 3Ba, and Ca (83 outputs) flows through the electric coils 1Ca, 2Ca, and 3Ca. A magnetic field moving from the right (+ y) to the left (-y) along the long side 1 acts on the molten metal in the mold.

The function generator 84 is supplied with a fourth AC period synchronizing pulse Pb _180, which clears its address counter (not shown) _.
Is 180 ° out of phase with Pbo, and if the current flowing through the electric coil based on the current-carrying duty data generated by the function generator 81 becomes Aa in FIG. 7, for example, the current generated by the function generator 84 is generated. The current flowing through the electric coil based on the duty data is Ab in FIG. Function generator 85
Is supplied with a fifth AC period synchronizing pulse Pb _60, which clears its address counter (not shown), and because Pb ₆₀ is 60 ° out of phase with Pbo, the function generator The current flowing through the electric coil based on the current-carrying duty data generated by 85 is Bb in FIG. The function generator 86 is supplied with the sixth AC period synchronizing pulse Pb _300, which clears the address counter (not shown). Therefore, Pb ₃₀₀ has a phase delay of 300 ° from Pbo. Therefore, the electric coil energizing current based on the energizing duty data generated by the function generator 86 is Cb in FIG. Bb is 120 ° out of phase with Cb, and Ab is 240 ° out of phase with Cb.
° Note that the phase is late. In summary, as will be described later, the Ab (84 output) of the current (waveform) flowing through the electric coil based on the energizing data output from these function generators 84 to 86 is output from the electric coil 4 shown in FIG.
Ab, 5Ab, 6Ab, Bb (85 outputs) flow to the electric coils 4Bb, 5Bb, 6Bb, and Cb (86 outputs) flow to the electric coils 4Cb, 5Cb, 6Cb. Left along long side 2 (-y)
From right to (+ y) acts on the molten metal in the mold.

The function of the energizing pulse generator 61 will be described with reference to FIG. The output data of the function generator 81 (A in FIG. 7)
a) is given to the multiplier 612. The drive current setting unit 611 supplies the amplification factor data to the multiplier 612. The setting unit 611 has an absolute encoder for the operator to specify the amplification factor. When the knob of the encoder is turned, the output code indicating the numerical value of the encoder changes to the one corresponding to the rotation angle. Here, the amplification factor is a value of 0 or more. Multiplier 612 provides adder 614 with energization duty data indicating a value obtained by multiplying the value represented by the duty data provided by function generator 81 by the data (amplification factor) provided by setter 611. . For example, when the gain provided by the setting unit 611 is 1, the reference current Is (FIG. 6) flows through the electric coil 1Aa, but when the gain is larger than 1, the current becomes Iaa shown in FIG. When the gain is less than 1, a current lower than the reference current Is flows through the electric coil.

In addition to the energization duty data (designating the current value for flowing molten steel) multiplied by the above-described amplification factor, the braking current setting unit 613 includes a braking current setting data in the adder 614. Give The setting unit 613 also has an absolute encoder for the operator to specify the braking current value (energization duty for determining). When the knob of the encoder is turned, an output code indicating a numerical value of the encoder is obtained.
It changes to the one corresponding to the rotation angle. Here, the braking current value is
0, a positive value and a negative value. When the encoder knob is at the neutral position, the encoder outputs data representing 0, and when the encoder is rotated clockwise from the neutral position, it represents a positive value corresponding to the rotation angle. −
When the data is rotated in the counterclockwise direction from the neutral position, data representing the negative value of the absolute value corresponding to the rotation angle is output to the adder 614. For example, when the data provided by the setting unit 613 is a positive value exceeding the braking current value 0 (for example, Ib in FIG. 6 is designated), the electric coil 1Aa includes a current for driving the flow of molten steel (for example, Iaa in FIG. 6). ) Is shifted by Ib in the positive direction,
Iba shown in FIG. 6 flows. That is, the electric coil current is
A DC bias I for braking is added to the current Iaa for driving molten steel flow.
b is added. When the data provided by the setter 613 is a negative value, the electric coil current is obtained by shifting the current Iaa for flowing molten steel in the negative direction.

Output data of adder 614 (the value represented by it)
The polarity discriminator 615 detects the positive and negative polarities of the AND gates 620 and 62. When the positive polarity is detected, a high level H is detected, and when the negative polarity is detected, a low level L polarity detection signal is output.
1 and the data indicating the absolute value of the output data of the adder 614 is added to the adder 616 and the feedback calculator 622.
Give to. The feedback calculator 622 calculates (from the current target value of the electric coil (the current value indicated by the absolute value of the output data of the adder 614)) the absolute value of the current flowing through the electric coil (the current shown in FIG. 2). Data indicating the value obtained by subtracting the output of the detector 415 is latched (stored) in the latch 623 in synchronization with the pulse Pa. The output data of the latch 623 indicates a correction amount necessary for setting the current value flowing through the electric coil as the current target value. When the correction value is a positive value, the required increase amount of the energizing current value (energizing duty) is determined. , A negative value indicates a required down amount.

The adder 616 has a target current value (adder 61).
The value obtained by adding the correction amount (the output of the latch 623) to the absolute value of the output data of No. 4 is output to the counter 617. In addition,
When the correction amount provided by the latch 623 is a negative value, the adder 616 substantially performs the subtraction. Counter 61
7, a pulse obtained by delaying the pulse Pa by the delay unit 618 is given as a load instruction signal, and a clock pulse Pd is given as a count pulse. The counter 617 outputs a pulse ( When the load pulse rises to a high level H, the output data of the adder 616 is loaded, and when the load pulse falls, the clock pulse P is output.
d is counted, and the count value is the load value (adder 616).
When the output data coincides with the output data, a carry signal is generated and the flip-flop 619 is reset. The flip-flop 619 is set at the falling edge of the load pulse, inverts the Q output from L to H, is reset by the carry signal, and returns the Q output from H to L. As a result, the Q output of the flip-flop 619 rises in synchronization with the pulse Pa, and falls after a lapse of time (the number of pulses Pd) indicated by the output data of the adder 616 from the rise. In addition,
The reason why the load pulse is delayed from the pulse Pa is
The output data of the function generator 81 is switched in synchronization with the pulse Pa.
Since there is a processing time (delay time) for calculation, determination, and the like by the adder 614, the polarity discriminator 615, and the adder 616,
This is to wait for completion of all calculations and determinations.

The aforementioned Q output of flip-flop 619 is provided to AND gates 620 and 621. These AND gates 620 and 621 are also provided with a polarity detection signal (the output of the discriminator 615), and this is the AND gate 6
20 is input as it is, and the inverted signal is input to the AND gate 621. Therefore, when the output data of the adder 614 indicates a positive value, the AND gate 620 outputs the high-level Q output. H energization instruction signal Pdp only during H
When the output data of the adder 614 indicates a negative value, the AND gate 621 generates the H conduction instruction signal Ndp only while the Q output is at the high level H.
These signals Pdp and Ndp change in time series as shown in FIG. 6 corresponding to changes in the output data of the function generator 81, and are applied to the GTO drivers 413 and 414 of the excitation circuit 41 shown in FIG. Given. The GTO driver 413 makes the GTO 411 conductive only while the signal Pdp is H, whereby a positive current flows through the electric coil 1Aa only while the signal Pdp is H. GTO driver 414
Makes the GTO 412 conductive only while the signal Ndp is H,
Thus, a positive current flows through the electric coil 1Aa only while the signal Ndp is at H. By these, electric coil 1
The current Aa (time-series smoothed value) of Aa is Iba shown in FIG. The fluctuation of the current Iba between the positive peak and the negative peak is a molten steel flow driving current component determined by the output of the multiplier 612, and the driving current setting unit 611 sets the positive peak by the driving current setting unit 611.
The level difference between the peak and the negative peak, that is, the alternating current value, that is, the molten steel driving force can be adjusted. DC bias component Ib of Iba
Is a braking current component determined by the output of the braking current setter 613, and can be adjusted by the braking current setter 613. That is, the braking force can be adjusted by the braking current setter 613.

The other energizing pulse generators 62 to 69 and 71 to 79 are also the energizing pulse generator 61 shown in FIG.
And operates similarly.

With the above configuration, electric currents Aa shown in FIG. 7 are applied to electric coils 1Aa, 2Aa and 3Aa shown in FIG.
A current in which the amplitude of (81 outputs) and the DC bias are adjusted for each electric coil flows, and the electric coils 1Ba, 2Ba, 3
A current in which the amplitude and the DC bias of the current waveform Ba (82 output) shown in FIG. 7 are adjusted for each electric coil flows through Ba, and the current waveform Ca (83 shown in FIG. 7) flows through the electric coils 1Ca, 2Ca, and 3Ca. Since the electric current whose amplitude and DC bias are adjusted for each electric coil flows through the first set of magnetic poles 11 to 19, the right (+)
The magnetic field moving from y) to the left (-y) changes the magnitude for each magnetic pole and acts on the molten metal in the mold, and a braking magnetic field (static magnetic field) having a different magnitude for each magnetic pole is applied to the molten metal. Works.

Similarly, the electric coils 4Ab, 5A shown in FIG.
Abs and 6Abs receive a current in which the amplitude and DC bias of the current waveform Ab (84 output) shown in FIG. 7 are adjusted for each electric coil, and the electric coils 4Bb, 5Bb, and 5Bb shown in FIG.
6Bb, a current in which the amplitude and the DC bias of the current waveform Bb (85 outputs) shown in FIG. 7 are adjusted for each electric coil flows, and the electric coils 4Cb, 5Cb, and 6Cb shown in FIG. Since the current in which the amplitude and the DC bias of the waveform Cb (86 output) are adjusted for each electric coil flows, the second set of magnetic poles 21 to 29 moves from the left (-y) to the right (+ y) along the long side 2 of the mold. The magnetic field moves to the molten metal in the mold, changing the size for each magnetic pole, and
A braking magnetic field (static magnetic field) having a different magnitude for each magnetic pole acts on the molten metal.

In this embodiment, due to the moving magnetic field and the braking magnetic field described above, the mold travels from right to left along the long side 1 of the mold shown in FIG. 1, hits the short side 4 and reaches the long side 2 along the short side 4, Proceeding from left to right along the long side 2, hitting the short side 3 to the long side 1, along each side and around the outside of the nozzle 30, the velocity is as high as possible in this flow direction It is intended to generate a uniform molten steel flow. By the way, nozzle 30
The molten steel flows into the mold from above, and a molten steel flow as shown by solid arrows in FIGS. 8A and 8B is generated. The flow velocity distribution in the arrangement direction of the magnetic poles 11 to 19 on the long side 1 surface due to the molten steel flow is roughly indicated by a solid line in FIG. 9A, and the magnetic poles 21 to 29 arrangement on the long side 2 surface. The flow velocity distribution in the direction is roughly indicated by a solid line in FIG.

By reducing the high flow velocity of the molten steel flow near the nozzle 30, the entrainment of powder is suppressed, the floating of the inclusions in the molten steel becomes easy, and the molten steel flows at a position where the molten steel tends to stay (slow). And the molten steel flow along the mold side surface is made to have a constant direction and constant speed in the horizontal direction, so that the horizontal temperature distribution of the solidified surface of the molten steel by the mold side surface becomes uniform and the blower The generation of noise is suppressed. In order to achieve this, the flow rate of the molten steel may be set to a constant value at each portion in the horizontal direction, for example, as shown by a dashed line in FIG. In the example shown in FIG. 9, the lower-left hatched area requires braking, and the lower-right hatched area requires driving. In order to satisfy this, the required current value of each electric coil wound around each magnetic pole is shown in FIG.
0. Note that, in FIG.
(Electric coil 3Ca) needs to be driven, but FIG. 10A shows that a braking current needs to flow in addition to the driving current. The braking current is applied to suppress the excessive rise of the molten steel at the corner between the long side 1 and the short side 4 due to the molten steel flowing to the left along the long side 1 hitting the short side 4. Is to multiply. In FIG. 9A, although the magnetic pole 11 (electric coil 1Aa) needs to be driven,
FIG. 10A shows that it is necessary to supply a braking current in addition to the driving current. This braking current suppresses the excessive swelling of the molten steel at the corner between the long side 1 and the short side 3 due to the collision of the molten steel toward the long side 1 along the short side 3 with the short side 3. The brake is applied.

The drive current of each electric coil shown in FIG. 10 (the value shown by the downward-sloping hatched bar graph) is set by the drive current setting unit (611) of the energization pulse generators 61-69, 71-79. The braking current of the coil (the value indicated by the left-downward slanted bar graph) is supplied to the energizing pulse generators 61 to 69, 71.
The setting is made by the braking current setting device (613) to 〜79. As a result, the flow velocity distribution is roughly indicated by the dashed line in FIG. 9, and the molten steel flows in the direction (indicated by the dashed line arrow) in FIG. In the immediate vicinity of the surface of No. 4, the flow becomes a unidirectional flow at a substantially constant speed.

In the above embodiment, the function generators 81 to 81 are used.
At 86, duty data for forming a sine wave current is generated. At the energization pulse generators 61 to 69, 71 to 79, the drive current setting unit 611 is applied to the energization duty data provided by the function generator. Is multiplied by the amplification factor given by the above, the duty obtained by the DC bias given by the braking current setting unit 613 is added to the obtained product, and the obtained sum is further added to the duty obtained by the deviation from the target value due to the current feedback. The output data (energization duty) is obtained by adding the duty. That is, the output data is calculated by digital arithmetic processing of the energization duty data.

However, the energization duty may be determined by another known processing method in energization duty control. For example, sine wave voltages are generated by the function generators 81 to 86,
The sine wave voltage is converted into a drive current setter 6 by a variable gain amplifier.
Amplification is performed at the amplification factor (analog signal) output from the DC amplifier 11 and the output thereof is supplied to the operational amplifier by the DC bias value (analog signal) output from the braking current setting unit 613 and the deviation from the target value due to current feedback (analog) Signal) (by biasing the output of the variable gain amplifier), and the obtained sine wave voltage is compared with a predetermined period and a predetermined level of 3 by a comparator.
When the sine wave voltage is higher than the triangular wave compared to the square wave (analog signal), the GTO 411 is turned on, and the GTO 412 is turned on.
Is turned off, and when the sine wave voltage is lower than the triangular wave, G
By performing signal processing by an analog electric circuit such as turning off the TO 411 and turning on the GTO 412, for example, the current Iba shown in FIG.

Further, in the above embodiment, the electric coil 1
Aa and the like are mounted on the magnetic pole bases 10 and 20 so as to circumnavigate the magnetic pole 11 and the like, that is, circumscribe a straight line parallel to the x-axis. These electric coils 1Aa and the like are shown in FIG. As shown, the magnetic pole bases 10 and 20 may be mounted so as to go around the trunk between the magnetic poles, that is, to go around a straight line parallel to the y-axis (FIG. 1).

[0039]

As described above, according to the flow control device of the present invention, a plurality of magnetic poles (11 to 19) for exciting each of a plurality of magnetic poles (11 to 19) arranged along the mold side (1) surrounding the molten metal are provided. AC coil (1Aa-3Aa, 1Ba-3Ba, 1Ca-3Ca), AC biasing means (81-83; 61-69,611,612,615-621; 41-49)
However, a linear drive AC current (Iaa: Aa, Ba, Ca) for flowing and driving the molten metal in the arrangement direction of the magnetic poles is energized, and DC biasing means (61 to 69, 613, 614, 615 to 621; 41) ~ 49),
Since a braking direct current (Ib) for braking the molten metal is applied, the molten metal is flow-driven in the direction in which the magnetic poles are arranged by the alternating current of the electric coil, and is braked by the direct current. That is, the same electric coil is shared for the flow drive and the braking. Therefore, the flow driving can flow the molten steel to remove the blowhole on the solidified surface of the molten steel, and also suppress the flow velocity of the injected molten steel by braking to facilitate the floating of inclusions (for example, powder). Can be In this way, the same electric coil can perform flow driving for suppressing or removing the blowhole and braking for suppressing inclusion of inclusions and promoting levitation.

[Brief description of the drawings]

FIG. 1 is a view showing an arrangement of magnetic poles and electric coils according to an embodiment of the present invention, showing a horizontal section of a continuous casting mold.

FIG. 2 is a block diagram showing an energizing circuit connected to the electric coil shown in FIG.

FIG. 3 shows excitation circuits 41 to 49 and 51 to 59 shown in FIG.
FIG. 3 is a block diagram showing an energization control circuit that supplies an energization signal to the power supply.

FIG. 4 is a block diagram showing a configuration of an energizing pulse generator 61 shown in FIG.

FIG. 5 is a block diagram showing a configuration of a function generator 81 shown in FIG.

FIG. 6 shows one cycle of a time-series smoothed value of the current flowing through the electric coil 1Aa shown in FIGS. 1 and 2 for one cycle Is (reference value), Iaa (drive force corrected for each coil).
And Iba (to which the driving force correction and the braking force correction have been performed), a pulse generated by the pulse generation circuit 90 shown in FIG. 3, and a time chart showing an energization instruction signal generated by the energization pulse generator 61 shown in FIG. It is.

7 is a time chart showing a time-series smoothed value of a current flowing through an electric coil according to energization duty data generated by function generators 81 to 86 shown in FIG.

8A is a vertical sectional view of the molds (1 to 4) shown in FIG. 1, and FIG. 8B is a horizontal sectional view.

FIG. 9 (a) is a view showing a mold in a horizontal direction along the surface of the long side 1 at the height of the magnetic pole 11 or the like by injecting molten steel from the nozzle 30 into the molds (1 to 4) shown in FIG. FIG. 4B is a graph showing the flow velocity distribution of the molten steel in the mold, and FIG. 4B is a graph showing the flow velocity distribution of the molten steel in the mold in the horizontal direction along the long side 2 surface.

10A is a diagram showing a driving current and a braking current necessary for flattening the flow velocity distribution shown in FIG. 9A and flowing through the electric coil 1Aa and the like arranged on the back side of the long side 1. FIG. (B) is a driving current and a braking current required for flattening the flow velocity distribution shown in (b) of FIG. 9 and flowing through the electric coil 1Ab and the like disposed on the back side of the long side 2. FIG.

FIG. 11 is a view showing an arrangement of magnetic poles and electric coils according to another embodiment of the present invention, wherein (a) shows a horizontal section of a continuous casting mold, and (b) shows an arrow B shown in (a). It is a side view of a direction.

[Explanation of symbols]

 1: Long side of the mold 2: Long side of the mold 3: Short side of the mold 4: Short side of the mold 10: Magnetic pole base 11 to 19: First set of magnetic poles 1Aa: Electric coil wound around the magnetic pole 11 1Ba: Electric coil wound around the magnetic pole 12 1Ca: Electric coil wound around the magnetic pole 13 3Ca: Electric coil wound around the magnetic pole 19 20: Magnetic pole base 21 to 29: Second set of magnetic poles 4Ab: Electric coil wound around magnetic pole 21 4Bb: Electric coil wound around magnetic pole 22 4Cb: Electric coil wound around magnetic pole 23 6Cb: Electric coil wound around magnetic pole 29 30: Injection of molten steel Nozzles 31, 32: Yoke 41-49, 51-59: Exciting circuit 61-69, 71-79: Energizing pulse generator

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takaji Ueyama 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Takehiko Fuji 20-1 Shintomi, Futtsu City Nippon Steel Corporation (72) Inventor Eiichi Takeuchi 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Headquarters (56) References JP-A-62-203648 (JP, A) JP-A Sho 63-188461 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 11/115 B22D 11/04 311 B22D 11/10 B22D 11/18

Claims (2)

(57) [Claims] 1. The first, second,..., M × n, m ≧ 3, n ≧ 1, arranged along the sides of a mold surrounding a molten metal.
Magnetic poles; first, second, and third poles for exciting each of these magnetic poles;
.., M × n electric coil; signal generating means for generating m consecutive signals for forming a linear drive AC current waveform; Amplifying means for amplifying at the amplification rate addressed to
Means for biasing the output signal of the amplifying means by a bias value addressed to each of these electric coils, and first, m + 1, 2m + 1,... For energizing each of the electric coils at an energizing duty corresponding to the biased signal. ..Coil drivers; amplifying means for amplifying the second series of signals at the second, m + 2, 2m + 2,... Amplification factors addressed to the respective electric coils;
Means for biasing the output signal of the amplifying means by a bias value addressed to each of these electric coils, and second, m + 2, 2m + 2,... For energizing each of the electric coils at a current-carrying duty corresponding to the biased signal. ..Coil driver; amplifying means for amplifying the m-th series of signals at the m-th, 2m, 3m,... Amplification factors addressed to the respective electric coils, and output signals of the amplifying means addressed to the respective electric coils .. A coil driver for energizing each of the electric coils with an energizing duty corresponding to the biased signal, and a mth, 2m, 3m,... Coil driver. 2. The first, second,..., M × n arrangements where m ≧ 3 and n ≧ 1 are arranged along a mold side surrounding the molten metal.
Magnetic poles; first, second, and third poles for exciting each of these magnetic poles;
··· m × n electric coil; memory means for storing energization duty data for forming an alternating current waveform; read addresses of the memory means are sequentially updated at a predetermined cycle Tpa to produce the alternating current waveform. With a predetermined phase
means for reading out m-th energization duty data;
.., 1m + 1,..., Multiplication means for multiplying the amplification rate addressed to each of the electric coils, addition means for adding a bias value addressed to each of these electric coils to the obtained product, The first, m +, energizing each of these electric coils for the time indicated by the sum obtained by the adding means
1, 2m + 1,... Coil driver; The second m +
.., 2m + 2,..., Multiplication means for multiplying the amplification factor addressed to each of the electric coils, addition means for adding the bias value addressed to each of these electric coils to the obtained product, A second and a second power supply to each of these electric coils for a time indicated by the sum obtained by the adding means.
m + 2, 2m + 2,... coil driver;
.. m, 3m,..., multiplication means for multiplying the amplification factor addressed to each of the electric coils, addition means for adding a bias value addressed to each of these electric coils to the obtained product,
The m-th, 2m-th and 3rd m-th powers are supplied to each of these electric coils for a time indicated by the sum obtained by the adding means within a predetermined period Tpa.
m, a coil driver;