JP3089176B2 - 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 control device for controlling a flow speed of a molten metal in a mold.

[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 flow-driven in a mold along a mold wall by using a linear motor (for example, Japanese Patent Application Laid-Open No. 1-228645).

FIG. 8A shows a vertical sectional view of a mold.
FIG. 8B shows a plane in which the upper surface (meniscus) of the molten steel in the mold is viewed from above the mold. Molten steel flows into the mold from the nozzle 30 as shown by the solid line arrow in (a), causing molten steel flow in the direction of the mold short piece and slightly downward, which hits the mold short piece, partly upward and the other downward. Flows. The molten steel flow flowing upward generates a surface flow toward the nozzle 30 at the meniscus as shown by a solid line arrow in FIG. 8B. This surface flow tends to entrain the powder on the meniscus. On the other hand, when molten steel changes to a solid, CO
Gases (bubbles) are generated. In addition, if the molten steel stays in a part of the inner surface of the mold, the powder tends to remain in the molten steel, and it is easy to cause seizure which causes breakout. In order to prevent these, it is preferable to form a stable rectification on the surface layer as shown by a two-dot chain line arrow in FIG. 8B.

As shown in FIG. 10 (b), the electromagnetic driving force in the direction indicated by the dotted arrow is applied to the molten steel by the linear motors 3RF and 3RL along the mold long piece against the surface flow caused by the molten steel flow. If given a circulating flow along the mold inner wall 1 as shown by a solid line arrow in FIG. 10 (c) on the surface layer of the molten steel, the circulating flow is generated in the surface layer portion by a two-dot chain line in FIG. 10 (b). A circulating flow as indicated by an arrow will be generated stably at a constant speed, thereby promoting the floating of bubbles,
Powder is not entangled in the molten steel, the inner surface of the mold near the surface layer is wiped cleanly, and the stagnation of the molten steel is eliminated.

[0005] By the way, the one generally used as an electromagnet of a linear motor in the past is a coil end type in which one side of a tortoise-shaped (hexagonal) electric coil is inserted into each slot cut into an electromagnet core. There is. That is,
For example, in the case of a three-phase linear motor, the slots are numbered in the order of their arrangement. Numbered 1, 2, 3,... Assuming that the tooth between Nos. 1 and 2 is numbered No. 2, one of a pair of long sides facing each other of the first tortoise-shaped electric coil is slot No. 2. 1 to slot No. 1.
3 and go around two teeth (No.2, 3) between the slots,
One of the pair of long sides facing each other of the second electric coil is slot No. 2 to slot No. 2. 4 and two teeth (Nos. 3 and 4) between the slots are rotated, and one of the pair of long sides facing each other of the third electric coil is inserted into the slot No. 4. 3
To the other slot No. 5 and insert the teeth between the slots (N
o.4,5) Each electric coil is mounted on the electromagnet core, so that two coils are orbited. Such a coil end method has a large power factor and can use a high-frequency power supply, so that the power supply capacity can be reduced. That is, the equipment cost is low.

[0006]

However, in the above-mentioned coil end system, the coil end protruding from the electromagnet core is large, the projection length in the direction x in which the slot extends is long, and the outside of the core in the direction y in which the slot is distributed. The length (sum of two short side lengths) is long. In addition, for example, in the above example, the slot No. Outside the side end of the third (x direction),
A large number of coil ends exist outside the side ends of the electromagnet core, for example, the short sides (coil ends) of the second and third electric coils overlap and protrude, thereby greatly increasing the width of the entire linear motor. ing.

However, the width of the mold (short side length)
Is relatively narrow, the nozzle for injecting molten steel into the mold is located substantially at the center of the opening of the mold, and the space between the tundish above the nozzle and the upper end of the mold is limited so that the coil is limited. There is a problem that it is difficult to dispose the end type linear motor above the mold opening. When the size of the linear motor is reduced, the thrust applied to the molten metal decreases. In order to provide a large thrust, the mold must be modified, which increases the equipment cost.

It is an object of the present invention to effectively apply thrust to the molten metal in the mold from the mold opening side.

[0009]

The molten metal flow control device of the present invention has a plurality of slots extending in the x direction and distributed in the y direction, and the tips of the teeth between the slots are formed on the upper surface of the molten metal in the mold. An electromagnet core (10) opposite to and within the mold opening;
A plurality of electric coils (a plurality of electric coils (10), which are inserted into the slots, are attached to the electromagnet core (10) by body winding around the base (10b) of each slot of the electromagnet core (10), and a part thereof is located above the upper end surface of the mold. 1Aa to 2Ca); and energizing means (20F1) for applying an AC voltage having a phase difference to each of the electric coils to apply a thrust to the molten metal along the slot arrangement direction y to the molten metal;
Is provided. In the parentheses, for easy understanding, the symbols of the corresponding elements of the embodiment shown in the drawings and described later are added for reference.

A preferred embodiment of the present invention is directed to a mold having a pair of long sides (5F, 5L) extending in the y direction and a pair of short sides (3R, 3L) extending in the x direction. , One of the long sides of a pair
(5F) and a plurality of first sets of slots extending in the x-direction, wherein the tips of the teeth between the slots are located close to one of the pair of short sides (3R). A first electromagnet core (10) facing the upper surface and within the mold opening; inserted in a first set of slots and wound around a base (10b) of each slot of the first electromagnet core (10); (1) a plurality of first sets of electric coils (1Aa to 2Ca) mounted on the electromagnet core (10), a part of which is located above the upper end face of the one long side (5F); An AC voltage having a phase difference for applying a thrust to the molten metal along the arrangement direction y to a first set of electric coils;
First current applying means (20F1) for applying to each of (1Aa to 2Ca);
It has a plurality of second sets of slots distributed along the other of the pair of long sides (5L) and extending in the x direction, and the tips of the teeth between the slots are located on the other of the pair of short sides (3L). A second electromagnet core (2) facing the upper surface of the molten metal in the nearby mold and located in the mold opening.
0); inserted into the second set of slots, the second electromagnet core (20)
Is attached to the second electromagnet core (20) by a torso winding around the base (20b) of each slot, and a part of the other long side (5L)
A plurality of second sets of electric coils (4Ab to 5Cb) located above the upper end face of the second set; and the arrangement direction y of the second set of slots
Second energizing means (20L2) for applying an AC voltage having a phase difference for applying a thrust to the molten metal along the second direction to each of the second set of electric coils (4Ab to 5Cb).

[0011]

[Action] A plurality of electric coils (1
Aa ~ 2Ca) is a body winding, so a plurality of electric coils (1Aa
~ 2Ca) is distributed in the y-direction around the same y-axis, and each electric coil has substantially no coil ends inserted in only one slot and extending in the y-direction. Thus, the length of the coil projecting outward (in the x direction) from the side end surfaces of the teeth between the slots is extremely small, and the overall width of the linear motor is small.
The tips of the teeth between the slots of the electromagnet core (10) can be inserted into the mold (mold) opening to approach the surface of the molten metal near the inner wall of the mold, thereby providing thrust to the molten metal effectively. it can. This can be implemented in existing molds without any particular improvement.

In addition, the linear motor is moved closer to the mold piece so that a part of the electric coil is located above the upper end surface of the mold.
Since (10 + 1Aa ~ 2Ca) is installed, thrust along the inner wall of the mold is positively applied to the molten metal, and the flow of the molten metal promotes the floating of bubbles in the molten metal. Powder entrainment is eliminated, and the inner surface of the mold near the surface layer is wiped cleanly, thereby eliminating the accumulation of molten metal. If the molten metal stays on the inner surface of the mold, the cooling effect of the mold acts strongly, so that the staying portion solidifies rapidly and the solidified metal adheres to the inner surface of the mold, which may cause breakout.

In the preferred embodiment of the present invention, two sets of linear motors (10 + 1Aa to 2Ca / 20 + 4Ab to 5Cb) are provided along the long side of the mold at diagonal positions of the mold opening (quadrilateral). In addition, since a part of the electric coil is disposed very close to the long side so as to be above the upper end face of the long side, the surface flow on the surface of the molten metal can be effectively adjusted. For example, a thrust (indicated by a dashed arrow in FIG. 1) can be applied to the molten metal in a direction opposite to the surface flow of the molten metal appearing by the projecting flow of the injection nozzle (30). In this case, FIG. As shown in FIG. 8, a relatively uniform surface flow is formed, and as a result, a stable circulating flow at a relatively constant speed as shown by a two-dot chain line arrow in FIG. 8B is obtained. As a result, the floating of bubbles is promoted, powder is not entrained in the molten metal, the inner surface of the mold near the surface layer is wiped clean, and the molten metal is not retained. Linear motor (10 + 1Aa-2Ca / 20
+ 4Ab to 5Cb) is only one pair and exists only in one of the two diagonal directions of the quadrangular space, so there is a lot of free space above the molten metal, and other devices or sensors can be easily arranged. . Since only one pair of energizing circuits is required, power consumption is small and energizing control is simplified. Therefore, equipment costs and maintenance costs are reduced.

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

[0015]

FIG. 1 shows an arrangement of a linear motor according to an embodiment of the present invention. In the figure, 5F and 5L are first and second long pieces of the continuous casting mold, and 6R and 6L are first and second long pieces.
Molten steel is injected into the space surrounded by these short pieces through the injection nozzle 30 from the front side to the back side (from the upper side to the lower side in the vertical direction z) of FIG. Each side (5F, 5
(L, 6R, 6L) are copper plates 1F, 1L, 3R, 3L and non-magnetic stainless plates 2F, 2L, 4R, 4L. As shown in FIG. 3, a stainless steel cover plate is placed on the upper end surface of each side of the mold, but is not shown in FIGS. 1 and 2.

In this embodiment, the mold (5F, 5L, 6
R, 6L) is a three-phase linear motor type with a long piece of 5L.
First and second electromagnets facing the upper surface of molten steel in a continuous casting mold (5F, 5L, 6R, 6L) for driving from right to left (from + y to -y) along Core 1
0 and 20 are arranged diagonally about the injection nozzle 30.

FIG. 2A shows an enlarged vertical section of the first electromagnet core 10 (an enlarged section taken along line 2A-2A in FIG. 1), and FIG. 3 shows an enlarged horizontal section of the electromagnet core 10 (FIG. 1). 3
(A-3A line enlarged section) is shown. In these drawings, the small numbers between the dimension leader lines (dashed lines) are dimension values (mm).
Is shown. The first linear motor including the first electromagnet core 10 and the second linear motor including the second electromagnet core 20 have the same dimensions and the same electrical rating. They are arranged symmetrically with respect to the axis.

Referring to FIGS. 1 to 3, in this embodiment, the electromagnet core 10 is long in the y direction,
Is formed by laminating comb-shaped thin steel plates having six notches for slots at equal pitches, and has six slots. Each of the slots has an electric coil 1Aa-2.
Ca is inserted. The electromagnet core 10 and the electric coils 1Aa to 2Ca are cooled and covered with a heat-resistant cover, but the cooling structure and the cover are not shown. The electromagnet core 10 has a comb shape having slots extending in the x direction on the lower surface. An electric coil is inserted into each slot, the teeth between the slots are magnetic poles, and the lower end surface thereof is a continuous casting mold (5F, 5L, 6R, 6L) faces the upper surface of the molten steel. The coil ends of the electric coils 1Aa to 2Ca protruding in the x direction from the electromagnet core 10
In the space above F (in the + z direction), it turns upward by approximately 90 degrees and passes through the upper plane of the electromagnet core 10. That is, the electric coils 1 </ b> Aa to 2 </ b> Ca are “wrapped around” the electromagnet core 10.

In this embodiment, the electric coils 1Aa to 2C
Electromagnetic core 10 having a height (z) of 150 mm in the inner space of a
After passing through, the width of the inner space of the electric coils 1Aa to 2Ca in the height direction z is 150 mm, and the depth of the slot (z ) Is 75 mm, so that after the electric coil is pushed into the slot, a gap of 75 mm is generated between the upper side of the electric coil and the back surface (upper surface) of the core 10. An auxiliary core 10a formed by laminating rectangular thin steel plates is inserted into this gap. Both the electromagnet core 10 and the auxiliary core 10a also have a cooling fluid flow path to which a refrigerant pipe is connected, but these are not shown.

Since the electric coils 1Aa to 2Ca are body-wound with respect to the electromagnet core 10, each electric coil is distributed only in the y direction by an amount corresponding to the slot width in the y direction, as in a conventional coil end type linear motor. In addition, one electric coil does not extend in the y direction by several slots, so that the protruding length of the electromagnet core 10 in the outer direction (x direction) is short, and the width of the linear motor (10 + 1Aa to 2Ca) in the x direction is narrow. . Thus, as shown in FIG. 3, the tip of the tooth between the slots of the electromagnet core 10 is inserted into the mold opening, and a part of the electric coil is placed above the mold wall 5F.
0 can be placed very close to the mold side 5F. In other words, since the width of the linear motor in the x direction is narrow, it is possible to arrange the linear motor even in a mode where the short side width is narrow, and furthermore, it is possible to effectively thrust the molten steel near the inner surface of the mold side. , The electromagnet core 10 can be placed in the immediate vicinity of the mold side.

FIG. 2B shows an enlarged vertical cross section of the second electromagnet core 20 (an enlarged cross section taken along line 2B-2B in FIG. 1). The electromagnet core 20 has the same structure as that of the electromagnet core 10, and is positioned with respect to the long side 5L and the short side 6L, similarly to the arrangement positional relationship of the first electromagnet core 10 with respect to the long side 5F and the short side 6R.

FIG. 4 shows how the electric coils 1Aa to 2Ca and 4Ab to 5Cb shown in FIGS. 2A and 2B are connected and connected to a power supply circuit. This connection is 2 poles (N = 2)
And a three-phase alternating current (M = 3) is supplied to the electric coil. For example, the electric coils 1Aa to 2Ca are represented as u, V, w, U, v, W in this order in FIG. “U” represents the U-phase normal-phase energization of three-phase alternating current (current energization as it is), “u” represents the U-phase reverse-phase energization (energization 180 degrees out of phase with the U-phase), and the electric coil “U” , A U-phase is applied to the winding start end, whereas the electric coil “u”
Means that the U phase is applied to the end of the winding.
Similarly, “V” indicates the positive-phase energization of the V-phase of three-phase AC, and “v”
Represents reverse-phase energization of V-phase, “W” represents normal-phase energization of W-phase of three-phase AC, and “w” represents negative-phase energization of W-phase. The terminals U11, V11 and W11 shown in FIG.
2Ca are power connection terminals, and terminals U12, V12 and W12 are power connection terminals of the electric coils 4Ab to 5Cb.

FIG. 5 shows a power supply circuit 20F1 for supplying a three-phase alternating current to the electric coils 1Aa to 2Ca. Three-phase AC power supply (3
Thyristor bridge 2 for DC rectification
2A1 is connected, and its output (pulsating flow) is smoothed by the inductor 25A1 and the capacitor 26A1. The smoothed DC voltage is applied to a power transistor bridge 27A1 for forming a three-phase AC, and the U-phase of the three-phase AC output from the power transistor bridge 27A1 is connected to the power supply connection terminal U11 shown in FIG. And the W-phase is connected to the power connection terminal W11.
Is applied to

A coil voltage command value VdcA1 for the electric coils 1Aa to 2Ca to generate a thrust indicated by a dotted arrow in FIG. 10B is given to a phase angle α calculator 24A1, and the phase angle α calculator 24A1 The conduction phase angle α (thyristor trigger-phase angle) corresponding to the value VdcA1 is calculated, and a signal representing this is provided to the gate driver 23A1. Gay
The driver 23A1 starts the phase counting of the thyristor of each phase from the zero cross point of each phase and triggers conduction at the phase angle α. Thereby, the transistor bridge 27
The DC voltage indicated by the command value VdcA1 is applied to A1.

On the other hand, the three-phase signal generator 31A1 operates at the frequency designated by the frequency command value Fdc (50H in this embodiment).
z) to generate a constant-voltage three-phase AC signal,
Give to 1. The comparator 29A1 also includes a triangular wave generator 3
0A1 gives a constant voltage triangular wave of 3 KHz. Comparator 2
9A1 is a high-level H (transistor on) signal when the U-phase signal is at a positive level or higher when the triangular wave generated by the triangular wave generator 30A1 is higher than the triangular wave level, and a low level L (transistor off) when the U-phase signal is lower than the triangular wave level. To the U-phase positive section (to the U-phase positive voltage output transistor). When the U-phase signal is at a negative level, it is lower than the level of the triangular wave provided by the triangular wave generator 30A1. When the signal is at the high level H, and when the level exceeds the triangular wave level, the signal at the low level L is sent to the negative section of the U phase (U
Gate driver 2 to the phase negative voltage output transistor)
Output to 8A1. The same applies to the V-phase signal and the W-phase signal. The gate driver 28A1 is connected to each of these phases,
Each transistor of the transistor bridge 27A1 is turned on and off in response to signals addressed to the positive and negative sections. As a result, a three-phase AC U-phase voltage is output to the power supply connection terminal U11, a similar V-phase voltage is output to the power supply connection terminal V11, and a similar W-phase voltage is output to the power supply connection terminal W11. The level between the upper and lower peaks of these voltages is determined by the coil voltage command value VdcA1. In this embodiment, the frequency of the three-phase voltage is 50 Hz based on the frequency command value Fdc.
It is. That is, a 50-Hz three-phase AC voltage having a peak voltage value (thrust) specified by the coil voltage command value VdcA1 is applied to the electric coils 1Aa to 2Ca shown in FIGS.

FIG. 6 shows a power supply circuit 20L2 for supplying a three-phase alternating current to the electric coils 4Ab to 5Cb. This power supply circuit 20
The configuration of L2 is the same as that of 20F1 described above, but the coil voltage command value (VdcB2) is different.

That is, a coil voltage command value VdcB2 at which the electric coils 4Ab to 5Cb generate a thrust indicated by a dotted arrow in FIG. 10B is given to the phase angle α calculator 24B2. The coil voltage command value VdcA1 (FIG. 5) and the coil voltage command value VdcB2 (FIG. 6) are supplied to the power supply circuits 20F1 and 20L2 by the computer 43 shown in FIG.
To give.

FIG. 7 shows the mold short pieces 6L and 6L shown in FIG.
The back of R is shown. On these short pieces 6L and 6R, thermocouples S31 to S3n and S41 to S4n are arranged at regular intervals in a row in a slab drawing direction (height direction z; vertical direction), respectively. Detects the temperature of the copper plate that penetrates the backing stainless plate and is slightly inside (the surface in contact with the molten steel). The signal processing circuits 41A and 41B generate an analog signal (detection signal) indicating the temperature detected by the thermocouple and supply the analog signal to the analog gate 42.

The computer 43 includes an analog gate 42.
To control the thermocouples S31 to S3n and S41 to S4
n detection signals are sequentially selected, A / D converted and read,
By the high temperature value extraction processing 44, the maximum temperature value Tm1L1 and the next highest temperature value Tm2L1 among the detected temperatures of the thermocouples S31 to S3n are extracted, and the maximum temperature value Tm1R1 among the detected temperatures of the thermocouples S41 to S4n. And the next highest temperature value Tm2R1 is extracted. Then, the representative temperature (Tm1L1−Tm2L1) × 0.7 + TM2L1 of the short piece 6L is calculated, and the representative temperature (Tm1R1−Tm2R1) × 0.7 + TM2R1 of the short piece 6R is calculated. Temperature difference (Tm1L1-Tm2L1) × 0.7 + TM2L1− (Tm1R1-Tm2R1) × 0.7−T
M2R1 is calculated, and when it is a positive value (0 or more) (the temperature of the short piece 6R is higher), VdcA1 = representative temperature difference ×
A (A is a coefficient) is calculated, and VdcB2 = B−VdcA
1 is calculated. When the representative temperature difference is a negative value (the temperature of the short piece 15L is higher), VdcB2 = −representative temperature difference ×
A is calculated, and VdcA1 = B−VdcB2 is calculated.

VdcA1 is the electric coil 1A on the short piece 6R side.
VdcB2 is a current level (thrust) command value for a to 2Ca (FIG. 4), and VdcB2 is the electric coil 4Ab to 5A on the short piece 6L side.
This is the current level (thrust) with respect to Cb (FIG. 4). These command values are applied to the electric coils of the electric coils 1Aa to 2Ca when the representative temperature difference is a positive value (the temperature of the short piece 6R is higher; the unbalanced surface flow shown in FIG. The applied three-phase AC current level is increased to apply a strong thrust (dotted arrow in FIGS. 1 and 9b), and the electric coil 4A
When the representative temperature difference is a negative value (the temperature of the short piece 6L is higher), the current flowing through the electric coils 4Ab to 5Cb is reduced.
This means that the phase alternating current level is increased to apply a strong thrust, and the three-phase alternating current level flowing through the electric coils 1Aa to 2Ca is decreased to decrease the thrust.

When the molten steel flow (protruding flow shown in FIG. 8A) flowing from the nozzle 30 into the mold is substantially symmetric with respect to the nozzle 30, the temperatures of the short pieces 6R and 6L are substantially the same, and the surface flow is reduced as shown in FIG. (B) and (a) of FIG. 9 are symmetrical with respect to the nozzle 30 as indicated by solid arrows, in this case, VdcA1 = VdcB2, and the electric coils 1Aa to 2Ca on the short piece 6R side and the short piece 6L side The electric current levels of the electric coils 4Ab to 5Cb are substantially equal, and the first electromagnet core 10 and the second electromagnet core 20 have substantially the same strength as shown by the dotted arrows in FIGS. 1 and 8B. , Giving a thrust in the opposite direction to the molten steel. As a result, the actual surface flow of the molten steel has a shape in which the solid line arrow in FIG. 10C is changed in the opposite direction, and a circulating flow indicated by a two-dot chain line arrow in FIG. Thereby, the floating of bubbles is promoted, the powder is not entrained in the molten steel, the inner surface of the mold near the surface layer is wiped clean, and the stagnation of the molten steel is eliminated.
The temperature distribution of the molten steel in the mold becomes uniform.

As shown in FIG. 11A, when the protruding flow toward the short piece 6R is strong and the protruding flow toward the short piece 6L is weak, the temperature of the short piece 6R increases, the temperature of the short piece 6L decreases, and the surface layer flow decreases. 11B, the surface flow between the nozzle 30 and the short piece 6R is strong and the surface flow between the nozzle 30 and the short piece 6L is weak as indicated by the solid arrow in FIG. 11B. In this case, VdcA1> VdcB2 The energization level of the electric coils 1Aa to 2Ca on the short piece 6R side is high, and the short piece 6L
The energization level of the electric coils 4Ab to 5Cb on the side becomes low, so that the first electromagnet core 10 gives a strong thrust and the second electromagnet core 20 gives a weak thrust to the molten steel. Thereby, as shown by the dotted arrow in FIG. 9B, the first electromagnet core 10 gives a strong thrust and the second electromagnet core 20 gives a weak thrust to the molten steel. This results in a circulating flow indicated by a two-dot chain line arrow in FIG. In this case, the circulating flow is high-speed on the high-temperature short piece 6R side and low-speed on the low-temperature short piece 6L side,
Since it is a circulating flow that draws a loop, no vortex is generated. Short piece 6
The high temperature molten steel on the R side is conveyed to the low temperature short piece 6L side to reduce the temperature difference. By this circulation flow, the floating of bubbles is promoted,
Powder is not entangled in the molten steel, the inner surface of the mold near the surface layer is wiped cleanly, and the stagnation of the molten steel is eliminated. The temperature distribution of the molten steel in the mold becomes uniform.

On the contrary, the projecting flow toward the short piece 6R is weak,
When the protruding flow toward the short piece 6L becomes strong, the temperature of the short piece 6R decreases, the temperature of the short piece 6L increases, and the surface flow
The surface flow between 0 and the short piece 6R is weak, and the surface flow between the nozzle 30 and the short piece 6L is strong. In this case, VdcA
1 <VdcB2, and the electric coil 1Aa on the short piece 6R side
The power supply level of ~ 2Ca is low, and the power supply level of the electric coils 4Ab-5Cb on the short piece 6L side is high, so that the first electromagnet core 10 gives a weak thrust and the second electromagnet core 20 gives a strong thrust to the molten steel. Thereby, as shown by a dotted arrow in FIG. 9C, the first electromagnet core 10 applies a weak thrust to the second electromagnet core 20 and applies a strong thrust to the molten steel. This allows
A circulating flow indicated by a two-dot chain line arrow in FIG.
In this case, the circulating flow has a low speed on the low temperature short piece 6R side,
Although the speed is high at the high temperature short piece 6L side, it is a circulating flow that draws a loop, so that no vortex is generated. The high-temperature molten steel on the short piece 6L side is conveyed to the low-temperature short piece 6R side to reduce the temperature difference. Due to this circulation flow, the floating of bubbles is promoted, powder is not entrained in the molten steel, the inner surface of the mold near the surface layer is wiped clean, and the stagnation of the molten steel is eliminated. The temperature distribution of the molten steel in the mold becomes uniform.

In the above embodiment, the temperature of the short pieces 6R and 6L is detected by a thermocouple, and the strength (flow velocity) of the surface flow corresponding to the strength of the protruding flow from the injection nozzle 30 into the mold is detected. Correspondingly stable circulation flow (two-dot chain line arrow in FIG. 8b)
Is applied to the molten steel by the first and second electromagnet cores 10 and 20. For example, the velocity Vs of the surface flow at the position Vspa in FIG.
The velocity Vsb of the surface flow at the positions of a and Vspb is detected, and the current level instruction values VdcA1 and VdcB2 are respectively calculated as Vdc
The value may be inversely proportional to sa and Vsb.
In the present invention, since only a pair of electromagnets are arranged diagonally above the mold space, a flow velocity sensor is provided to detect the flow velocity at the positions Vspa and Vspb, or
It is easy to raise and lower spa and Vspb.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement of magnetic poles and electric coils above a molten steel surface of a continuous casting mold according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of electromagnet cores 10 and 20 shown in FIG.

FIG. 3 is an enlarged cross-sectional view of the electromagnet cores 10 and 20 shown in FIG.

4 is an electric circuit diagram showing the connection of the electric coils shown in FIG. 2 and the connection with a power supply circuit.

5 is an electric circuit diagram showing a power supply circuit for applying a three-phase AC voltage to electric coils 1Aa to 2Ca shown in FIG.

6 is an electric circuit diagram showing a power supply circuit for applying a three-phase alternating current to electric coils 4Ab to 5Cb shown in FIG.

FIG. 7 is a block diagram showing the backs of the short pieces 6L and 6R of the casting mold shown in FIG. 1 and an electric circuit connected to a thermocouple provided therein.

FIG. 8 (a) shows the template (5F, 5L, 6) shown in FIG.
F, 6R) is a vertical sectional view, and (b) is a horizontal sectional view.

FIG. 9A is a plan view showing the upper surface of molten steel in a mold;
(B) and (c) are plan views showing surface flows (dotted arrows) induced on the meniscus of the molten steel in the mold by the electromagnets 10 and 20.

FIG. 10 (a) is a plan view showing a surface layer flow caused by molten steel injection from an injection nozzle in a meniscus of molten steel in a mold, and FIG. 10 (b) is a surface flow to be generated by two conventional linear motors. And (c) is a plan view showing by a solid line arrow the vector sum of the surface flow generated by the injection of molten steel from the injection nozzle and the surface flow generated by the thrust of the two linear motors.

11A is a sectional view of molten steel in a mold, and FIG. 11B is a plan view showing a surface layer flow in a meniscus of the molten steel in the mold.

[Explanation of symbols]

1: Inner wall of mold 1F, 1L, 3R, 3
L: Copper plate 2F, 2L, 4R, 4L: Non-magnetic stainless steel plate 5F, 5L: Long piece 6R, 6L: Short piece 10, 20: Electromagnetic core 10a, 20a: Auxiliary core 10b, 20b: Base 19: Outlet 30: Injection nozzle 20F1, 20L2:
Power supply circuit PW: Powder 1Aa, 1Ba, 1Ca, 2Aa, 2Ba, 2Ca: Electric coil 4Ab, 4Bb, 4Cb, 5Ab, 5Bb, 5Cb: Electric coil U11, V11, W11 / U12, V12, W12: Power connection terminal

Continuation of the front page (56) References JP-A-62-207543 (JP, A) JP-A-6-182518 (JP, A) JP-A-63-104763 (JP, A) JP-A-61-129266 (JP, A) JP-A-6-304719 (JP, A) JP-A-6-47513 (JP, A) JP-A-8-108257 (JP, A) JP-A-55-54245 (JP, A) 5-111552 (JP, A) JP-A-1-228645 (JP, A) JP-A-60-72652 (JP, A) JP-A-57-91855 (JP, A) JP-A-6-182517 (JP, A) A) JP-A-7-246445 (JP, A) JP-A-61-14052 (JP, A) JP-A-57-75268 (JP, A) JP-A-58-100955 (JP, A) JP-A-8 JP-A-197211 (JP, A) JP-A-8-187563 (JP, A) JP-A-7-290214 (JP, A) JP-A-62-203648 (JP, A) JP-A-51-95665 (JP, A) JP-A-60-68146 (JP, A) JP-A-6-606 (JP, A) JP-A-5-154623 (JP, A) Shokai Sho 62-149802 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 11/04 311 B22D 11/115

Claims (3)

(57) [Claims] 1. An electromagnet core having a plurality of slots extending in the x direction and distributed in the y direction, wherein tips of teeth between the slots face the upper surface of the molten metal in the mold and are located in the mold opening; A plurality of electric coils mounted on the electromagnet core with a torso winding around the base of each slot of the electromagnet core, a part of which is located above the upper end surface of the mold; and a thrust along the slot arrangement direction y is melted. An energizing means for applying an alternating voltage having a phase difference to be applied to the metal to each of the electric coils; 2. A plurality of slots distributed along the long side and extending in the x direction of a mold including a pair of opposite long sides extending in the y direction and a pair of short sides extending in the x direction. An electromagnet core having tips of teeth between the slots facing the upper surface of the molten metal in the mold and in the mold opening; the electromagnet core being inserted into the slots and being wound around the base of each slot of the electromagnet core. A plurality of electric coils which are mounted on the upper surface of a long side of the mold, and a part of which is provided with an AC voltage having a phase difference for applying a thrust to the molten metal along the slot arrangement direction y. A flow control device for a molten metal, comprising: 3. A mold including one pair of long sides extending in the y-direction and including a pair of short sides extending in the x-direction and distributed along one of the pair of long sides in the x-direction. A first electromagnet having a plurality of first sets of slots extending therein, the tips of the teeth between the slots facing the upper surface of the molten metal in the mold at a position near one of the pair of short sides and within the mold opening; A core inserted into the first set of slots, attached to the first electromagnet core with a torso winding around the base of each slot of the first electromagnet core, a portion of which is located above an upper end surface of the one long side; Multiple first
A pair of electric coils; a first energizing means for applying an AC voltage having a phase difference for giving a thrust to the molten metal along the arrangement direction y of the first set of slots to each of the first set of electric coils; It has a plurality of second sets of slots distributed along the other of the long sides and extending in the x direction, and the tips of the teeth between the slots are located on the upper surface of the molten metal in the mold near the other of the pair of short sides. A second electromagnet core opposite and within the mold opening;
A plurality of second electromagnet cores, each of which is inserted into a set of slots and is attached to the second electromagnet core by a torso winding around the base of each slot of the second electromagnet core, and a portion of which is located above an upper end surface of the other long side; Two sets of electric coils; and second energizing means for applying, to each of the second sets of electric coils, an alternating voltage having a phase difference for applying a thrust to the molten metal along the arrangement direction y of the second set of slots; A flow control device for molten metal comprising: