JP6394731B2 - Method for melting metal materials - Google Patents

Description

  The present invention relates to a method for melting a metal material, for example, a method for melting a metal material by induction heating.

  2. Description of the Related Art Conventionally, an induction heating apparatus that melts a metal material in a crucible by induction heating by flowing an alternating current through an induction coil arranged on the outer periphery of the crucible has been used. For example, a melting apparatus is known in which a nozzle communicating with the bottom of a crucible is provided, and a high-frequency induction heating coil is disposed on the outer periphery of the nozzle (see Patent Document 1 below).

  In general, the capacity of the induction heating device is set to the minimum capacity for the purpose of reducing the initial investment, etc. Therefore, the amount of molten metal in the crucible is small at the initial stage of induction heating, and the area around the tap outlet provided at the bottom of the crucible is small. The temperature may not rise sufficiently. When a small amount of molten metal reaches the low temperature outlet, the temperature decreases and solidifies, and the outlet may be blocked by the solidified metal material. The metal material once solidified in the hot water outlet is not easily melted by the amount of heat supplied from the molten metal in the crucible, and it may be difficult to discharge the molten metal in the crucible from the hot water outlet.

JP-A 63-207984

  In the melting apparatus of Patent Document 1, after melting the metal material in the crucible by applying electric power to the high frequency induction heating coil provided on the outer periphery of the crucible in a state where the nozzle serving as the pouring gate is sealed with a metal plug in advance. Then, electric power is applied to the high frequency induction heating coil provided on the outer periphery of the nozzle to melt and drop the metal plug in the nozzle to open the nozzle. Therefore, according to the melting device of Patent Document 1, the metal plug that closes the nozzle can be melted, and the molten metal in the crucible can be discharged from the nozzle to the outside.

  However, in the melting apparatus of Patent Document 1, in order to melt the metal plug in the nozzle after melting the metal material in the crucible, it is necessary to provide an induction heating coil for the nozzle separately from the induction heating coil for the crucible. . Moreover, when discharging the molten metal material in the crucible, it is necessary to heat the metal plug in the nozzle again after the metal material is melted.

  The present invention has been made in view of the above problems, and can discharge the molten metal material in the crucible from the outlet to the outside without heating the outlet again after melting the metal material in the crucible. An object is to provide a method for melting a metal material.

  In order to achieve the above object, the melting method of the metal material according to the present invention is a method in which high frequency is applied to an induction heating coil disposed around the crucible in a state where the outlet of the crucible containing the metal material is sealed with a preheating sealing member. A first step of flowing an electric current to melt the metal material by induction heating and heating the preheating sealing member to preheat the hot water outlet to a temperature equal to or higher than the melting point of the metal material; It consists of a second step of extracting the stop member and discharging the molten metal material in the crucible to the outside from the outlet.

  The metal material accommodated in the crucible in the first step is not particularly limited as long as it is a metal that can be melted by induction heating. For example, a steel material such as iron or steel or a non-ferrous metal material such as aluminum or titanium is suitable. As a material for the crucible, for example, a high melting point material such as tungsten or molybdenum or a heat resistant material such as carbon or graphite can be used. The shape of the crucible is not particularly limited, but can be a cylindrical shape, for example. The crucible outlet may be provided on the bottom or side of the crucible, preferably on the lower side, and may include through holes, nozzles or pipes and joints as components.

  As a material of the preheating sealing member that seals the tap, a material that can be heated by induction heating and has a melting point higher than the melting point of the metal material to be melted in the crucible, for example, a high melting point material such as tungsten or molybdenum Can be used. The shape and size of the preheating sealing member are defined as a shape and size that can be fitted into the tap and that can prevent the leakage of the molten metal in the crucible by sealing the tap. The dimension of the preheating sealing member is defined as a dimension that can be extracted from the tap, considering thermal expansion due to induction heating, for example. The preheating sealing member is configured to be inserted into or removed from the hot water outlet by, for example, moving forward or backward with respect to the hot water outlet by an appropriate driving device.

  The induction heating coil is connected to, for example, a high frequency power source and the like, and a high frequency current flows to generate an eddy current in the crucible or the metal material in the crucible to heat the crucible or the metal material by induction heating, and the metal material in the crucible The molten metal is stirred by electromagnetic force. In addition, the induction heating coil heats the preheating sealing member fitted in the hot water outlet by induction heating prior to induction heating of the metal material in the crucible or simultaneously with induction heating of the metal material in the crucible.

  In the first step of melting the metal material, first, a preheating sealing member is inserted into the hot water outlet of the crucible, for example, by the driving device, and the hot water outlet is sealed in advance. Next, a metal material is put into the crucible and a high-frequency current is passed through the induction heating coil to melt the metal material by induction heating. When melting the metal material put into the crucible, the preheating sealing member is heated by induction heating at the same time. The preheating sealing member may be heated in advance by induction heating prior to the introduction of the metal material.

  By sealing the crucible outlet with a preheating sealing member, a small amount of molten metal in the initial stage of induction heating of the metal material is prevented from flowing into the outlet and solidifying. Is prevented from being blocked. Further, by storing the molten metal in the crucible and increasing its volume, heat can be supplied from the molten metal to the hot water outlet and its vicinity, and the temperature at the hot water outlet and its vicinity can be raised. Further, the tap is heated by the preheating sealing member and preheated to a temperature equal to or higher than the melting point of the metal material.

  In the second step of melting the metal material, for example, the preheat sealing member is extracted from the hot water outlet of the crucible by the driving device, and the molten metal in the crucible is supplied to the outside from the hot water outlet. Here, since the outlet is preheated to a temperature equal to or higher than the melting point of the metal material charged into the crucible by the preheating sealing member, the temperature drop and solidification of the molten metal when the molten metal in the crucible passes through the outlet is reduced. This prevents the outlet from being blocked by the solidified metal material. Thereby, it becomes possible to discharge the molten metal material in the crucible more quickly and stably than the conventional one from the outlet.

  In addition, when discharging the molten metal material in the crucible from the outlet, it is only necessary to remove the preheating sealing member from the outlet, without heating the outlet again after the metal material in the crucible has melted, The molten metal in the crucible can be discharged to the outside from the outlet.

  As can be understood from the above description, according to the melting method of the metal material of the present invention, the induction disposed around the crucible in a state where the outlet of the crucible containing the metal material is sealed by the preheating sealing member. A high frequency current is passed through the heating coil to melt the metal material by induction heating, and the preheating sealing member is heated to preheat the outlet to a temperature equal to or higher than the melting point of the metal material. Therefore, by removing the preheating sealing member from the hot water outlet and discharging the molten metal material in the crucible to the outside from the hot water outlet, the inside of the crucible is not heated again after the metal material in the crucible has melted. The molten metal can be discharged to the outside more quickly and stably than the conventional hot water outlet.

It is the schematic cross section which showed embodiment of the melt | dissolution apparatus used for the melt | dissolution method of the metal of this invention. It is the schematic cross section which showed the state which the melt | dissolution apparatus shown in FIG. 1 melt | dissolved the metal material. It is the schematic cross section which expanded the vicinity of the tap of the melting apparatus shown in FIG. 1, (a) is a figure which shows the state after metal material addition, (b) is the figure which showed the state of the initial stage of induction heating (C) is the figure which showed the state at the time of melt | dissolution of a metal material. It is the schematic cross section which expanded the tap outlet vicinity of the conventional melt | dissolution apparatus, (a) is the figure which showed the state after metal material addition, (b) is the figure which showed the state of the initial stage of induction heating. Yes, (c) is a diagram showing the state of the metal material at the time of dissolution.

  Hereinafter, the method for melting a metal material of the present invention will be described with reference to the drawings.

(Dissolution equipment)
First, an example of an embodiment of a melting apparatus used in the metal material melting method of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing the melting apparatus of the present embodiment, and FIG. 2 is a schematic cross-sectional view showing a state in which the melting apparatus shown in FIG.

  The melting apparatus 1 according to the present embodiment includes a crucible 2 that contains a metal material, a preheating sealing member 3 that is fitted into the outlet 2c of the crucible 2, a drive unit 4 that drives the preheating sealing member 3, and a crucible. 2 and an induction heating coil 5 disposed around the periphery of the motor.

  The crucible 2 is formed, for example, in a bottomed cylindrical shape having an opening 2a at the top, and is configured so that the opening 2a can be sealed by a lid 2b. The crucible 2 and the lid 2b can be manufactured using a high melting point material such as tungsten or molybdenum or a heat resistant material such as carbon or graphite. At the bottom of the crucible 2, a hot water outlet 2 c for supplying the molten metal m in the crucible 2 to the outside is provided.

  The preheating sealing member 3 is defined in a shape and size that can be fitted into the outlet 2c of the crucible 2 and that can seal the outlet 2c and prevent the molten metal m in the crucible 2 from leaking. Moreover, the dimension of the preheating sealing member 3 is prescribed | regulated to the dimension which can be extracted from the hot water outlet 2c in consideration of thermal expansion. The preheating sealing member 3 can be made of a high melting point material such as tungsten or molybdenum.

  The drive unit 4 advances the preheating sealing member 3 relative to the hot water outlet 2c of the crucible 2 to insert the preheating sealing member 3 into the hot water outlet 2c and seal the hot water outlet 2c. Moreover, the drive part 4 opens the tap 2c by retracting the preheating sealing member 3 with respect to the tap 2c of the crucible 2 and extracting it from the tap 2c. The drive unit 4 includes, for example, an actuator, an advance / retreat mechanism, a control unit, and the like. The advance / retreat mechanism moves the preheating sealing member 3 to the outlet 2c of the crucible 2 by operating the actuator at a predetermined timing according to a command from the control unit. Move forward and backward. The mechanism of the drive unit 4 is not particularly limited as long as the preheating sealing member 3 can be inserted and removed. For example, a motor and an appropriate power transmission mechanism may be used.

  The induction heating coil 5 is connected to a high-frequency power source (not shown) and a high-frequency current is applied to the crucible 2 or the metal material in the crucible 2 to generate eddy currents and heat them by induction heating. The metal material in 2 is melted and the molten metal m is stirred by electromagnetic force. The induction heating coil 5 heats the preheating sealing member 3 that seals the outlet 2c of the crucible 2 by induction heating prior to melting of the metal material in the crucible 2 or simultaneously with melting of the metal material in the crucible. To do. The induction heating coil 5 can be manufactured by, for example, a copper tube, and can be cooled by circulating cooling water.

(Metal dissolution method)
Next, an example of an embodiment of the metal melting method of the present invention using the melting apparatus 1 described above will be described. FIG. 3 is an enlarged cross-sectional view of the vicinity of the outlet 2c of the crucible 2 of the melting apparatus 1, wherein (a) shows a state after the metal material M is put into the crucible 2, and (b) shows the induction of the metal material M. The state of the initial stage of a heating is shown, (c) has shown the state which is supplying the molten metal m of the metal material M outside.

  In the metal melting method of the present embodiment, first, the drive unit 4 shown in FIG. 1 is operated to advance the preheating sealing member 3 toward the hot water outlet 2c of the crucible 2, and the preheating sealing member 3 is moved to the hot water outlet 2c. And the hot water outlet 2c is sealed. After sealing the hot water outlet 2c, the metal material M to be dissolved in the crucible 2 is charged.

  Here, the metal material M is not particularly limited as long as it is a metal that can be melted by induction heating. For example, a steel material such as iron or steel or a non-ferrous metal material such as aluminum or titanium can be used.

  It should be noted that sealing of the tap 2c by the preheating sealing member 3 may be performed prior to the introduction of the metal material M into the crucible 2 or before the metal material M is melted after the metal material M is charged. You may go.

<First step>
In the first step, as shown in FIG. 3 (a), the induction disposed around the crucible 2 with the hot water outlet 2 c of the crucible 2 containing the metal material M sealed by the preheating sealing member 3. A high frequency current is passed through the heating coil 5 by a high frequency power source. As a result, a magnetic field penetrating the induction heating coil 5 is generated, and eddy currents flow through the metal material M and the preheating sealing member 3 to generate heat. Depending on the material, the crucible 2 also generates heat. By this induction heating, the metal material M is melted and the preheating sealing member 3 is heated to preheat the tap 2c. Due to the heat H generated by the preheating sealing member 3, the temperature at the outlet 2c and the vicinity thereof is preheated to a temperature equal to or higher than the melting point of the metal material M, for example.

  In addition, prior to charging the metal material M into the crucible 2, when the hot water outlet 2 c is sealed with the preheating sealing member 3, the preheating sealing member 3 is heated by induction heating before the metal material M is charged. The hot water outlet 2c may be preheated.

  As shown in FIG. 3B, a small amount of molten metal m generated in the initial stage of induction heating of the metal material M reaches the vicinity of the hot water outlet 2 c provided at the bottom of the crucible 2. However, since the outlet 2c of the crucible 2 is sealed by the preheating sealing member 3, the molten metal m is prevented from flowing into the outlet 2c and solidifying, and the outlet 2c is blocked by the solidified metal material. Is prevented. In addition, a small amount of the molten metal m generated in the initial stage of induction heating of the metal material M does not flow out and is stored in the crucible 2, so that the volume of the molten metal m in the crucible 2 increases. Thereby, heat h can be supplied from the molten metal m to the outlet 2c and its vicinity, and the temperature of the outlet 2c and its vicinity can be raised.

  In addition, the preheating sealing member 3 preheats the outlet 2c and the vicinity thereof to a temperature equal to or higher than the melting point of the metal material M, thereby reducing the temperature of the small amount of the molten metal m reaching the vicinity of the outlet 2c in the initial stage of induction heating. Can be raised. It is also possible to heat the molten metal m in the vicinity of the hot water outlet 2c with the heat H generated by the preheating sealing member 3. Accordingly, by performing induction heating of the metal material M in a state where the tap 2c is sealed by the preheating sealing member 3, a small amount of molten metal m generated in the initial stage of induction heating solidifies at and near the tap 2c. Can be prevented.

  As described above, the melting of the metal material M in the crucible 2 proceeds with the solidification of the molten metal m at and near the outlet 2c being prevented, and all the metal material M in the crucible 2 is melted as shown in FIG. And becomes molten metal m.

<Second step>
In the second step, the preheating sealing member 3 is extracted from the outlet 2c of the crucible 2, and the molten metal m of the metal material M in the crucible 2 is discharged from the outlet 2c and supplied to the outside. Specifically, as shown in FIG. 2, the drive unit 4 is operated from the state in which the preheating sealing member 3 is fitted into the hot water outlet 2 c so that the preheating sealing member 3 is moved away from the hot water outlet 2 c of the crucible 2. By retracting, the preheating sealing member 3 is extracted from the hot water outlet 2c and the hot water outlet 2c is opened. Thereby, as shown in FIG.3 (c), the molten metal m of the metal material M in the crucible 2 is discharged from the hot water outlet 2c, and is supplied outside.

  Here, since the outlet 2c of the crucible 2 and the vicinity thereof are preheated to a temperature equal to or higher than the melting point of the metal material M by the preheating sealing member 3, the molten metal m in the crucible 2 passes through the outlet 2c. Temperature drop and solidification are prevented, and the outlet 2c is prevented from being blocked by the solidified metal material. As a result, the molten metal m of the metal material M in the crucible 2 can be discharged from the outlet 2c more quickly and stably than in the past.

  Further, when the molten metal m in the crucible 2 is discharged from the hot water outlet 2c, it is only necessary to extract the preheating sealing member 3 from the hot water outlet 2c. Therefore, the molten metal m in the crucible 2 can be discharged from the outlet 2c to the outside without heating the outlet 2c again after the metal material M in the crucible 2 is melted.

  Here, a conventional melting apparatus 100 and a metal melting method will be described for comparison with the melting apparatus 1 and the metal melting method of the present embodiment. 4 is an enlarged cross-sectional view of the vicinity of the hot water outlet 102c of the crucible 102 of the conventional melting apparatus, (a) shows a state after the metal material M is put into the crucible 102, and (b) shows the state of the metal material M. The state of the initial stage of induction heating is shown, and (c) shows the state in which the metal material M in the crucible 102 is dissolved. The melting apparatus shown in FIG. 4 has the same configuration as the melting apparatus 1 of the present embodiment shown in FIG. 1 except that the preheating sealing member 3 and the drive unit 4 are not provided.

  As shown in FIG. 4A, a high-frequency current is passed through an induction heating coil disposed around the crucible 102 with a high-frequency power source in a state where the hot water outlet 102 c of the crucible 102 containing the metal material M is released. As a result, the metal material M is induction-heated and melted, but the temperature at the hot water outlet 102c of the crucible 102 and its surroundings may be lower than the melting point of the metal material M. In this case, as shown in FIG. 4 (b), a small amount of the molten metal m generated in the initial stage of induction heating reaches the outlet 102c and the vicinity thereof, the temperature is lowered, and solidifies at the outlet 102c and the vicinity thereof. There is a risk of doing.

  Once the metal material M1 solidified in the hot water outlet 102c is melted easily by the heat h supplied from the molten metal m even after all the metal material M in the crucible 102 is melted as shown in FIG. 4 (c). Otherwise, it may be difficult to discharge the molten metal m in the crucible 102 from the hot water outlet 102c. In addition, it is conceivable to provide a nozzle at the hot water outlet 102c and melt the metal material M1 solidified in the nozzle by applying electric power to an induction heating coil provided on the outer periphery of the nozzle. It is necessary to provide an induction heating coil. Further, after the metal material M in the crucible 102 is melted, it is necessary to heat the metal material M1 in the hot water outlet 102c again.

  On the other hand, according to the melting method of the metal material of the present embodiment, the crucible 2 is placed around the crucible 2 with the hot water outlet 2c of the crucible 2 containing the metal material M sealed by the preheating sealing member 3 as described above. A high frequency current is passed through the arranged induction heating coil 5 to melt the metal material M by induction heating, and the preheating sealing member 3 is heated to preheat the outlet 2 c to a temperature equal to or higher than the melting point of the metal material M. Therefore, even when the power capacity in the induction heating is minimized, it is possible to heat the tap 2c again after the metal material M in the crucible 2 is melted only by removing the preheating sealing member 3 from the tap 2c. In addition, the molten metal m in the crucible 2 can be discharged from the outlet 2c to the outside more quickly and stably than before.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

2 ... crucible, 2c ... outlet, 3 ... preheating sealing member, 5 ... induction heating coil, M ... metal material, m ... molten metal

Claims (1)

A high-frequency current is passed through an induction heating coil disposed around the crucible in a state where the outlet of the crucible containing the metal material is sealed by a preheating sealing member, and the metal material is melted by induction heating, and the metal Simultaneously with the induction heating for melting the material or prior to the introduction of the metal material, the preheating sealing member is heated from the initial stage of induction heating to a temperature equal to or higher than the melting point of the metal material, and the discharge is performed. A first step of preheating the gate to a temperature above the melting point of the metal material;
A second step of extracting the preheating sealing member from the tap and discharging the molten metal material in the crucible to the outside from the tap;
A method for melting a metal material comprising:

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