JP2011167715A - Continuous casting apparatus, method for manufacturing the same, and frequency setting standard table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous casting device in which product quality and production efficiency are improved without increasing complication of the device structure nor increasing the number of components. <P>SOLUTION: Electric power Px to be fed to an induction heating coil 18 is set to a value including a heat removal amount and sufficient for stably melting the material 13 to be melted, further, the value D.&radic;f obtained by multiplying the square root &radic;f of the frequency of the current to be energized through the induction heating coil 18 by the inside diameter D of a melting furnace 10 is defined as a magnetic Womersley corresponding value, and the magnetic Womersley corresponding value D.&radic;f is set so as to exceed the first value which is the smallest value in the range where the molten metal 14 can be stably melted through the frequency f. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a continuous casting apparatus that effectively improves the product quality and production efficiency of a cast product related to continuous casting, a method for manufacturing the continuous casting apparatus, and a frequency setting reference table used therefor.

  In the continuous casting method, melting is continuously performed while the material to be melted is melted in a solid or other melting device and supplied in liquid form, and during that time, a part of the molten metal is gradually separated from the melting zone. After cooling, melting and solidification are continuously performed, and these operations are continued to continuously form a cast product such as a long rod-like or thick plate-like ingot having the same cross-sectional shape as the cross-sectional shape of the dissolution zone. It is a method. As a continuous casting apparatus using this continuous casting method, there is a cold crucible induction melting continuous casting apparatus (see, for example, Patent Document 1).

  FIG. 5 is a cross-sectional view showing a configuration of a melting furnace (melting furnace) portion of the cold crucible induction melting continuous casting apparatus. Reference numeral 10A in the figure is a melting furnace of an induction continuous melting casting apparatus (for example, a cylindrical melting furnace having an inner peripheral surface diameter of about 80 mm), and the melting furnace 10A is used to manufacture a cast product having a circular cross section. A plurality of segments 16 having cooling water passages 16a are arranged in a circumferentially divided state through slits 17 of a predetermined size, and side walls 20 formed alternately adjacent to each other and on the outer peripheral side of the side walls 20 An induction heating coil 18 made of a hollow copper tube, spirally wound around the radial outer periphery of the side wall 20 with a predetermined interval, and having a cooling water passage 18a inside, and the side wall 20 It is composed of a water-cooled bottom plate 1 that is slightly smaller in diameter in the horizontal direction than the inner peripheral surface and arranged to be movable up and down with respect to the inner peripheral surface, and a drawing shaft 12 that moves the bottom plate 1 up and down. The induction heating coil 18 is appropriately supplied with a frequency from a power supply unit (not shown), and the power and frequency are set to empirical values that are sufficient to stably dissolve the material 13 to be dissolved on the spot.

  The bottom plate 1 includes an upper member 2 and a lower member 3, and both members are formed so that the outer diameter of the horizontal cross section is slightly smaller than the inner peripheral surface of the side wall 20. Has enough space to prevent leakage. The upper member 2 has a hollow cylindrical shape with a bottom that is short in the vertical direction. The hollow cylindrical upper member 2 is turned upside down so that the bottom portion 2a is upward and the hollow cylinder portion (cooling water chamber) 2d is downward. It is arranged to be. In the central portion in the radial direction of the bottom portion 2a disposed above, a non-penetrating recess, in this example, a hole 2b as a frustum-shaped space is provided, but the side surface 2c that defines the hole is tapered. Precisely, it is formed in a reverse taper shape and becomes wider as it goes inside the upper member 2 of the bottom plate, that is, downward. On the other hand, the lower member 3 is provided with two through-holes extending in the axial direction so as to communicate with the cooling water chamber 2d of the upper member 2 so that the cooling water inlet 3a and the outlet 3b are connected to each other. It has become. In addition, a drawing shaft 12 is fixed to the central portion of the lower member 3 in the radial direction.

  In this example, the upper member 2 and the lower member 3 of the bottom plate are integrated by seal welding from the outer peripheral side. By this seal welding, the hollow cylindrical portion becomes a cooling water chamber 2d communicating with the cooling water inlet 3a and the outlet 3b, and cools the entire bottom plate 1. Since the bottom plate 1 is cooled by water, it is not melted and the boundary between the material to be melted (dissolved object) 13 and the solidified phase 15 remains clearly. At the beginning of melting, the molten metal 14 flows into the non-through hole 2b. The hole 2b is filled to solidify integrally with the solidified phase at the bottom of the melt. When the pulling shaft 12 is lowered downward in this state, a tensile force is transmitted to the solidified phase 15 via the reverse tapered side surface 2c, and the solidified phase 15 and the molten metal 14 are gradually lowered. It changes to the solidification phase 15 with progress, and the length of a casting becomes large sequentially.

  The bottom plate 1 is further lowered, and such melting and solidification are continuously performed, and the solidification phase 15 is extended downward to form a rod-shaped casting (for example, about 300 mm to 400 mm). Length ingot). In this melting furnace 10A by induction heating, a bottom plate 1 that becomes a hearth in the initial melting process of the melting furnace 10A is provided so as to be movable up and down independently from the side wall 20 with a gap therebetween. 13 is gradually lowered while keeping the amount of the molten metal 14 constant, and the induction heating coil 18 moves away from the wound melting zone as the lower part of the molten metal 14 is lowered. When 18 is moved to the casting area where it is not wound and cooled, it is gradually solidified from the outer peripheral side, and further descends to the central part to form a round bar of metal or alloy.

JP-A-8-141705

  By the way, in the melting furnace 10A of the conventional cold crucible induction melting continuous casting apparatus shown in FIG. 5, the flow of the melt indicated by arrows A and B in the molten metal is caused by the electromagnetic force of the induction heating coil 18 at the solid-liquid interface (molten metal). The boundary between the solidified phase and the solidified phase) is generated above 15z, and the molten metal is stirred to work to make the temperature distribution in the molten metal uniform. In this case, the solid-liquid interface 15z in the central portion is dug down by the downward flow indicated by the arrow B in the flow that hits the central portion in the molten metal. For this reason, even if the drawn solidified mass (solidified phase) 15 deviates from the heating region of the induction heating coil 18, the inside of the solidified mass 15 melts to a deep portion in the drawing direction, and the solid-liquid interface 15z becomes concave.

  If the surface is concave, as shown in FIG. 6, since the thin portion 15a of the solidified mass 15 existing at the solidification interface 15z extends in the casting direction, a pulling force acts on the thin portion 15a from the extraction shaft 12. On the other hand, when a force in the direction of retaining from the seizing portion (fixed portion 15b) at the solidification start point X is applied, the middle fragile thin portion 15a is torn from both sides, resulting in cracks 15c and tearing. It becomes easy. As a result, the molten metal leaks out and re-solidifies easily. In addition, since the slit 17 is filled with a refractory material (not shown), the slit 17 may come off and adhere to a crack 15c or the like generated in the thin portion 15a of the solidified mass 15. Furthermore, since the solidification interface 15z is concave, primary crystals are generated from the side surfaces, making it difficult to grow crystals in one direction, and it is difficult to grow crystals with high unidirectionality due to a high flow rate.

  For this reason, as shown in FIG. 7, a defect part g1 such as a crack or a flaw is generated on the surface of a cast product G such as an ingot drawn out, a foreign matter g2 is mixed, or the crack is backfilled with molten metal. As a result, a discontinuous point g3 of the crystal structure is generated, resulting in a decrease in product quality, and it is difficult to recover sufficient quality even if a subsequent cutting process is performed. As a result, the production efficiency is lowered in combination with the need for a post process.

  An object of the present invention is to effectively solve such a problem without causing the complexity of the device structure and the increase in the number of parts.

  In order to achieve this object, the present invention takes the following measures.

  That is, the continuous casting apparatus of the present invention includes a melting furnace in which a plurality of segments having a cooling water passage therein are arranged in a cylindrical shape in the circumferential direction through slits, and a conductive material to be melted is introduced from above. An induction heating coil wound around an outer periphery of the melting furnace to form the molten metal by induction heating the material to be melted, and a bottom plate of the melting furnace is configured to be movable up and down, and by lowering the bottom plate, It is a continuous casting device that obtains a metal ingot by solidifying the metal melted in the melting furnace while solidifying it at the solid-liquid interface, and the power to be supplied to the induction heating coil includes the heat extracted and melted. The value is set to a value sufficient to stably melt the material, and the value obtained by multiplying the inner diameter of the melting furnace by the square root of the frequency of the current to be passed through the induction heating coil or a value proportional to the value is set to If you define a value, through the frequency the magnetic Womasurei corresponding value, and wherein the set to exceed the first value is the smallest value in the range of the molten metal enabling stable dissolution.

  The value corresponding to the magnetic womasley in this case indicates that if the inner diameter of the melting furnace is determined, the flow of the molten metal becomes gentler and the digging of the solidification interface becomes smaller as the frequency is increased. Therefore, if the first value that can be stably dissolved is determined as the value corresponding to the magnetic womasley and set to a frequency that gives a value corresponding to the magnetic womasley that exceeds this value, it can be stably dissolved and the digging amount is small and smooth. A concave solid-liquid interface can be realized.

  As a specific aspect for reliably setting the digging reduction rate above a certain value, the digging depth of the solid-liquid interface when the magnetic womasley-corresponding value takes the first value as a reference, In the case where the value corresponding to the magnetic womaslay where the digging reduction rate is a predetermined percentage is the second value, the frequency is set so that the value corresponding to the magnetic womasley is equal to or higher than the second value.

  Further, as another specific aspect for reliably setting the digging reduction rate to a certain value or more, the digging depth at the center of the solid-liquid interface is more than 100% with respect to the inner diameter of the melting furnace. In this case, the frequency is set so that the value corresponding to the magnetic worsley when the predetermined value is smaller than the third value is the third value.

  In order to appropriately manufacture any one of the above continuous casting apparatuses, the power to be supplied to the induction heating coil is set to a value sufficient to stably dissolve the material to be melted including the extracted heat, and then the value corresponding to the magnetic womasley is set. It is desirable to set a frequency that is a parameter.

  As one that can be used when manufacturing the continuous casting apparatus according to the above aspect, one of the vertical axis and the horizontal axis is the inner diameter of the melting furnace, the other is the frequency, and the value corresponding to the magnetic womasley takes the first value. A frequency setting reference table in which a stable melting line in which the values are combined and a digging reduction line in which the values corresponding to the magnetic womasley take the second value are shown in parallel is convenient.

  Alternatively, as one that can be used when manufacturing the continuous casting apparatus according to the other aspect described above, one of the vertical axis and the horizontal axis is the inner diameter of the melting furnace, the other is the frequency, and the value corresponding to the magnetic womasley is the first. A frequency setting reference table in which a stable dissolution line in which points that take values are connected and a digging down line in which points corresponding to magnetic womasley take a third value are written together is convenient.

  According to the present invention, it is possible to make a setting that can be stably dissolved and the amount of digging down of the solid-liquid interface can be appropriately relaxed based on the value corresponding to the magnetic womasley. It is possible to eliminate defects such as cracks and cracks in the lump and to generate discontinuous structures, reduce or eliminate post-processing such as cutting, and reliably improve the product quality of castings such as ingots. it can. In addition, the solid-liquid interface has a gentle concave shape, and a crystal structure with a large grain size is likely to grow. Therefore, coupled with the fact that subsequent processes can be reduced or eliminated, the production efficiency of castings such as ingots can be effectively improved. Is possible.

The figure which shows the structure of the melting furnace which concerns on one Embodiment of this invention. The figure which shows the part heat-extracted in a melting furnace. Action | operation explanatory drawing of the same embodiment. The graph which shows the frequency setting reference | standard table of the embodiment with an experiment example. The figure which shows the structure of the melting furnace of the conventional cold crucible induction melting continuous casting apparatus. The figure for demonstrating the cause which the conventional malfunction generate | occur | produces. The figure which shows the surface state of the ingot in which the conventional malfunction generate | occur | produced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a melting furnace according to the present embodiment. The melting furnace 10 shown in FIG. 1 has basically the same configuration as the conventional melting furnace 10A shown in FIG. 5, but here, after first setting the power Px necessary for heat removal, AC The oscillation frequency f generated in the power supply unit 4 is set to a value different from the conventional value based on a predetermined standard. Hereinafter, the method will be described step by step along with the reason.

  First, in order for the material to be melted (melting target) 13 of the melting furnace 10 to be kept in a molten state, it is necessary to continue to apply electric power superior to heat removal due to the structure.

As shown in FIG.
(1) Heat removal by contact with mold inner surface (arrow C1)
(2) Heat removal (arrow C2) by heat transfer (gas, radiation) between the gaps with the mold inner surface
(3) Heat removal (arrow C3) by heat transfer (gas, radiation) from the molten metal surface
It is. Here, the influence of heat removal power and the influence of frequency are considered. The heat removal of (1) and (2) can be assumed to be constant because it can be considered that there is no change in the shape of the surface where heat removal is performed even if the frequency changes. On the other hand, regarding the item 3), the shape of the molten metal surface 14z on which heat removal is performed changes due to the change in the frequency, and thus the heat removal changes.

  However, since most of the heat removal can be regarded as the above items (1) and (2), especially the item (1), it can be treated as having almost no influence on the heat removal even if the frequency changes as a whole. it can. If there is no change in heat removal, the frequency f can be changed regardless of the input power Px.

  Now, the flow B of the molten metal 14 forms a concave solid-liquid interface 15z, and the higher the flow rate, the more the solid-liquid interface, that is, the solidified surface 15z is dug down, and the generation of cracks as shown in FIG. As described above, it causes problems such as lowering of crystal growth and crystal growth. Therefore, in order to suppress the flow rate of the molten metal 14, it is considered to change the current I applied to the heating induction coil 18 shown in FIG. The power supply P (coil current value I) and the frequency f can be operated from the AC power supply unit 4 side, but the power P has an optimum value Px because of the relationship with heat removal. I can't change it. On the other hand, it is known that the frequency f does not affect the heat removal, and if the frequency f is increased while the power Px is constant, the flow rate of the molten metal 14 decreases. Therefore, after determining the power Px, the frequency f is changed. However, if the frequency f is extremely low, the induction is not effectively performed, so that a certain lower limit exists. In order to change the frequency f, the capacitance C is changed among L (reactance) of the heating induction coil 18 constituting the LC resonance circuit and the capacitance C of the capacitor 30. In a simple method, the number of capacitors 30 is increased or decreased, or the capacitance is adjusted by making the capacitors 30 variable. Although a parallel resonance circuit is used in the figure, it is of course possible to use a series resonance circuit.

  When the flow velocity of the molten metal 14 is decreased by increasing the frequency f, the speed of the flow B of the molten metal 14 shown in FIGS. 1 and 2 toward the solidification interface 15z can be decreased, the heat toward the solidification interface 15z can be decreased, and solidification can be achieved. The force of eroding the solid phase portion 15 of the interface 15z can also be reduced, and the solidification interface 15z can be raised. As a result, as shown in FIG. 3, the digging depth of the solidification interface 15z decreases with the height of the surface 14z of the molten metal 14 in the direction indicated by the white arrow in the figure, and the solidification interface 15z is used at the conventional frequency f. It is possible to realize a concave surface shape that is gentler than the position shown in FIG. 1 (ie, the position indicated by the imaginary line in FIG. 3). In this case, the condition for making the digging amount d equal to or less than a predetermined value is a condition between the inner diameter D of the melting furnace and the frequency f.

D · √f> K (i) (K: Empirical value including power condition)
There is a relationship.

  The above equation (i) is obtained from the magnetic Womaley number Wm of the following equation (ii).

Wm = L√ (ω / ν _m )> K ′ (ii)
(L: representative length → inner diameter, ω: angular frequency, ν _m = 1 / (σμ) → σ: conductivity, μ: permeability)

  In other words, the magnetic Womaley number Wm is proportional to the value obtained by multiplying the representative length (the inner diameter D of the melting furnace corresponds to this) by the square root of the angular frequency √ω (the frequency √f of the AC power supply corresponds to this). . In this sense, D · √f is referred to as a “magnetic woma sley corresponding value” in the present embodiment. The value corresponding to the magnetic womasley D · √f can be stably melted at the value K, and the larger the value K, the slower the flow velocity of the flow B of the molten metal 15 that digs the solid-liquid interface 15z and the amount of digging. It represents that d becomes small. Therefore, when the inner diameter D of the melting furnace is constant, the frequency f can be increased or decreased as a parameter.

  FIG. 4 shows an experimental example. When a frequency of 10 kHz is applied in a melting furnace (crucible) 10 with an inner diameter of 80 mm (point A in the figure), the digging depth d is about the height of the molten metal (generally a melting furnace). However, when the frequency is increased to 35 kHz (point B in the figure), the digging depth is reduced to about half of 10 kHz (that is, about half the inner diameter of the melting furnace), and the solidified structure and It was confirmed that the surface roughness of castings such as ingots was also improved. Similarly, the insoluble point “▲” and the dissolvable point “●”, which are data obtained under other conditions, are plotted in the same figure together with the digging performance (50%) point “■”.

  Further, in the same figure, the relationship between the inner diameter D of the melting furnace obtained from the equation (i) and the frequency f is shown along lines L1, L2, and L3.

  L1 in the figure is the “stable dissolution possible line” including the above point A and D · √f = 80 mm × √10000 = 8000 (first value). In the figure, L2 is the above point B. It is a “digging half line” under the condition of D · √f = 80 mm × √35000 = 15000 (second value or third value). In the figure, L3 is a “dissolvable line” under D · √f = 4500 (first value). Here, the line L1 that can be stably dissolved is a line that employs the lowest frequency value in the range in which the material to be dissolved 13 is stably dissolved without causing poor dissolution, and the digging half line L2 is The line adopting the value of D · √f (second value) such that the digging depth d is 50% of the digging depth in the stable melting possible line L1, or the melting furnace This is a line that adopts a value of D · √f (third value) such that it becomes 50% for a digging of the same depth as the inner diameter D. In this embodiment, the second value and the third value The values of are almost consistent. The meltable line L3 is an unstable melt line that employs a frequency value when the material 13 to be melted starts to melt. In the figure, as it goes up (that is, as the frequency becomes higher), melting progresses and the digging amount d decreases. However, since discharge occurs when the frequency f becomes too high, it is necessary to stop at a certain limit.

  When the melting furnace 10 is actually operated using such a frequency setting reference table as a clue, the first value corresponding to the magnetic womasley corresponding value D · √f is the smallest value in the range in which the molten metal 14 can be stably melted. More than the value K (ie, exceeding the line L 1), and more preferably, the magnetic womasley corresponding value D · √f is equal to or greater than the second value or the third value (ie, equal to or greater than the line L 2). The frequency f is set.

The relationship between the frequency f and the digging depth d can be considered from the viewpoint of stirring force. The stirring power is F (kg / cm ² ), the absorbed power of the molten metal is P (kW), the melting furnace diameter is D (cm), the coil winding height is L (cm), and the specific resistance of the molten metal is ρ (Ω · cm) and the frequency is f (Hz), the stirring force F is

F = 316P / (π · D · L√ρ · √f) (iii)
Indicated by A large stirring force F means that the flow rate of the molten metal 14 is fast. If the stirring is large, the solid-liquid interface 15z is dug and the height of the surface 14z of the molten metal 14 is increased. If it is small, the above digging and the height of the mountain will be small. It can be seen that in order to suppress the excavation and the height of the mountain to some extent, the frequency should be increased after setting the appropriate input power in the equation (iii) first.

  As described above, in the present embodiment, the electric power P to be supplied to the induction heating coil 18 is set to a value Px that includes the heat removal and is sufficient to stably dissolve the material 13 to be melted, and the inner diameter of the melting furnace 10. A value D · √f obtained by multiplying D by the square root √f of the frequency of the current to be passed through the induction heating coil 18 is defined as a value corresponding to the magnetic womasley. Since it is set so as to exceed the first value which is the smallest value within the range in which the molten metal 14 can be stably melted, the flow of the molten metal 14 digging the solid-liquid interface 15z in the melting furnace 10 increases the frequency f. 6, the digging amount d is reduced, and a gentle concave solidification interface 15 z is realized, so that the thin portion 15 a of the solidified mass 15 shown in FIG. 6 is replaced with a thick solidified mass as shown in FIG. 15 It can be. For this reason, as shown in FIG. 6, cracks and cracks 15c are prevented from occurring in the thin portion 15a of the solidified mass and the molten metal 14 is prevented from leaking therefrom, and the refractory material in the slit 17 may adhere to the cracks 15c and the like. Is prevented.

  In addition, crystal growth in one direction can be easily performed, and combined with the slow flow rate, crystal growth with high unidirectionality becomes possible. As a result, as shown in FIG. 7, a defective part g1 such as a crack or a flaw is generated on the surface of the cast product G such as an extracted ingot, a foreign matter g2 is mixed, or the crack is backfilled with a molten metal. As a result, the problem of reducing the quality of the product due to the occurrence of the discontinuous point g3 of the crystal structure is solved, and sufficient quality can be ensured by reducing or eliminating the subsequent cutting process.

  Furthermore, when the talk is advanced to the structure control, the solid-liquid interface 15z becomes a gentle concave surface as shown in FIG. 3, and a crystal structure with a large grain size is likely to grow. This is a concave surface in which the digging depth d of the solid-liquid interface 15z is equal to or larger than the inner diameter D, but it becomes a concave surface less than half of the inner diameter D. This is because the number of crystals can be reduced, and crystals with a large particle size are easily formed. In other words, a certain crystal growth distance is required in order to change from a crystal having a small particle size to a crystal having a large particle size, and the unidirectionality is ensured by securing the crystal growth distance by making the solid-liquid interface as horizontal as possible. It is possible to grow a crystal having a large grain size. Therefore, it is possible to improve the production efficiency more effectively in combination with increasing the drawing speed and reducing or eliminating the post-process.

  Specifically, in this embodiment, the digging reduction rate is 50 with reference to the digging depth d of the solid-liquid interface 15z when the magnetic womasley correspondence value D · √f takes the first value (8000). When the value (15000) of the magnetic woma sley corresponding value D that is% is set to the second value, the frequency f so that the magnetic woma sley corresponding value D · √f is equal to or greater than the second value (15000). By setting this, the digging reduction rate can be surely made 50% or more.

  Alternatively, the value of the magnetic womasley corresponding value D · √f when the digging depth d at the center of the solid-liquid interface 15z is 50% smaller than 100% with respect to the inner diameter D of the melting furnace 10 (15000). Is set to the third value (substantially the same as the second value in this embodiment), the frequency f is set so that the magnetic womasley correspondence value D · √f is equal to or greater than the third value (15000). As a result, the digging depth d can be reliably reduced to about half of the inner diameter D or more.

  Then, after setting the electric power Px to be supplied to the induction heating coil 18 to a value sufficient to stably dissolve the material to be melted 13 including the extracted heat, the frequency f which is a parameter of the magnetic womasley correspondence value D · √f is set. Therefore, the above continuous casting apparatus can be appropriately manufactured (set) and used.

  In this case, as shown in FIG. 4, the horizontal axis (may be the vertical axis) is the inner diameter D of the melting furnace, the vertical axis (may be the horizontal axis) is the frequency f, and the magnetic womasley corresponding value D · √f is A frequency setting reference table in which a stable melting line L1 connecting points having a value of 1 and a digging reduction line L2 connecting points where the magnetic womasley corresponding value D · √f takes the second value is shown side by side. Since it is used, the setting at which the digging reduction rate is equal to or greater than a predetermined% can be easily and reliably realized according to the inner diameter D.

  Alternatively, in the figure, the stable melting line L1 in which the magnetic womasley corresponding value D · √f takes the first value is connected to the stable melting line L1 where the magnetic womaslay corresponding value D takes the third value. Since the digging reduction line L3 is also shown in parallel, the setting from the viewpoint of making the digging depth d 50% or less of the inner diameter of the melting furnace 10 can be easily and reliably realized.

  The specific configuration of each part is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the embodiment, the value obtained by multiplying the inner diameter D of the melting furnace by the square root of the frequency f of the current to be passed through the induction heating coil is defined as the value corresponding to the magnetic womasley. A proportional value obtained by multiplying a value obtained by multiplying the square root of the frequency f of the current to be passed through the coil by a coefficient can also be defined as a value corresponding to the magnetic womasley.

  In the above embodiment, the digging reduction rate and the digging depth are set to 50%, but it goes without saying that various values can be set according to the purpose and application.

DESCRIPTION OF SYMBOLS 1 ... Bottom plate 10 ... Melting furnace 13 ... Material 15 ... Solidification phase 15z ... Solid-liquid interface 16 ... Segment 16a ... Cooling water passage 17 ... Slit 18 ... Induction heating coil d ... Depth of digging D ... Inner diameter D * √f ... Value corresponding to magnetic womasley f ... Frequency L1 ... Stable dissolution possible line L2 ... Digging half line L3 ... Dissolvable line Px ... Power

Claims (6)

A plurality of segments having cooling water passages inside are arranged in a cylindrical shape in the circumferential direction through slits, and a melting furnace in which a conductive material to be melted is introduced from above, and is wound around the outer periphery of the melting furnace. An induction heating coil for induction heating of the material to be melted to form a molten metal, and a bottom plate of the melting furnace is configured to be movable up and down, and the metal melted in the melting furnace by lowering the bottom plate is solid-liquid It is a continuous casting device that draws downward while solidifying at the interface and obtains a metal ingot,
While setting the electric power to be supplied to the induction heating coil to a value sufficient to stably dissolve the material to be melted including the extracted heat,
When a value obtained by multiplying the inner diameter of the melting furnace by the square root of the frequency of the current to be passed through the induction heating coil or a value proportional to the value is defined as a magnetic womalay corresponding value, the magnetic woma The continuous casting apparatus is set to exceed the first value which is the smallest value within a range in which the molten metal can be stably melted. Based on the digging depth of the solid-liquid interface when the magnetic woma sley corresponding value takes the first value, when the magnetic woma sley corresponding value at which the digging reduction rate is a predetermined percentage is the second value, The continuous casting apparatus according to claim 1, wherein the frequency is set so that the value corresponding to the magnetic womasley is equal to or greater than the second value. When the digging depth at the center of the solid-liquid interface is a predetermined value smaller than 100% with respect to the inner diameter of the melting furnace, the value corresponding to the magnetic wathlay is the third value, The continuous casting apparatus according to claim 1, wherein the frequency is set to be equal to or greater than the third value. It is a method for manufacturing the continuous casting apparatus in any one of Claims 1-3, Comprising: The electric power which should be supplied to an induction heating coil was set to the value sufficient to melt | dissolve a to-be-dissolved material stably including a heat removal part. Then, the frequency which is a parameter of a value corresponding to a magnetic womasley is set. It is used when manufacturing the continuous casting apparatus according to claim 3, wherein one of the vertical axis and the horizontal axis is the inner diameter of the melting furnace, the other is the frequency, and the value corresponding to the magnetic womasley is the first value. The frequency setting reference | standard table | surface characterized by writing together the stable melt | dissolution line which connected the point to take, and the digging reduction line which connected the point where a magnetic womasley corresponding value takes the 2nd value. It is used when manufacturing the continuous casting apparatus according to claim 4, wherein one of the vertical axis and the horizontal axis is the inner diameter of the melting furnace, the other is the frequency, and the value corresponding to the magnetic womasley is the first value. The frequency setting reference | standard table | surface characterized by writing together the stable melt | dissolution line which connected the point to take, and the digging reduction line which connected the point where a magnetic womasley corresponding value takes the 3rd value.

Images