KR20230081386A - The apparatus of electron beam melting - Google Patents

Abstract

Provided is an apparatus of melting an electron beam, which may facilitate the removal of impurities when melting high fusion point metal. The apparatus of melting an electron beam comprises: an electron beam chamber which includes a first electron gun generating an electron beam, a first coil concentrating the electron beam emitted from the electron gun, and a second coil secondarily concentrating the firstly concentrated electron beam, and heats a base material of high fusion point metal by emitting the electron beam concentrated from the second coil; a melting chamber which includes a mold forming an ingot by cooling molten metal obtained by melting the base material of the high fusion point metal, and a base material supply unit supplying the base material of the high fusion point metal into the mold; and an ingot chamber which is provided with an ingot puller that pulls out the ingot from the mold and then grows the ingot. The apparatus of melting an electron beam adjusts a current applied to the first coil and a current applied to the second coil, and adjusts a shape of the electron beam emitted on the base material of the high fusion point metal.

Description

The apparatus of electron beam melting}

The present invention relates to an electron beam melting device, and relates to an electron beam melting device capable of easily removing impurities, melting a metal having a high melting point while controlling a melting rate, and capable of growing a high-purity ingot.

Metals with high melting points, such as tantalum, molybdenum, titanium, and vanadium, are generally melted using vacuum arc remelting (VAR) or plasma arc melting (PAM), and ingots are formed. can be manufactured

Vacuum arc melting requires a separate manufacturing process for the melting material electrode, and since it can only be melted in the vertical direction, the uniformity of the ingot is reduced, and a continuous process may be impossible. Plasma arc melting has many melting process variables such as current size, gas flow rate, and raw material viscosity, and it is difficult to control the plasma gradient. In addition, both of the above two processes have difficulties in manufacturing high-purity ingots for semiconductors of 4N5 class (99.995% purity) or higher.

In order to solve this problem, metal melting techniques using an electron beam are known. For example, Korean Patent Registration No. 10-1342091 relates to a method for producing an ultra-high purity tantalum rod-shaped ingot having a purity of 99.995% or more and less than 100% using electron beam drip melting, 1) diameter of Φ20 mm or more and Φ100 mm or less preparing a green compact by compressing high melting point metal powder at a pressure of 1.0 ton/cm2 or more and 2.0 ton/cm2 or less using a steel compaction mold of; 2) preparing a button-type ingot by melting the green compact in an electron beam melting furnace; 3) welding the manufactured ingot in the form of a high melting point metal bar feeder; 4) continuously melting a high melting point metal bar feeder by electron beam drip melting using two electron beams including a circular main electron beam and a semicircular auxiliary electron beam at the same time; In Japanese Patent Registration No. 4860253, a detachable lining is provided on the inner surface of the melting furnace, and the lining is composed of a ceiling lining 81, a side wall lining 82, and a bottom lining 84, each independently detachable from the melting furnace. Also disclosed is an electron beam melting device in which the ceiling lining 81 is made of metal, and the side wall lining 82 and the bottom lining 84 are made of metal or resin, and a metal melting method using the device.

However, in Korean Patent No. 10-1342091, it is necessary to go through the process of welding again in the form of a bar fitter after making a button-type ingot, and Japanese Patent No. 4860253 is a technology for shortening the maintenance work of the furnace after melting, It can be said that it is more necessary to develop a technology that can effectively remove metal, control the dissolution rate of metal, and grow into a high-purity ingot.

Korean Registered Patent No. 10-1342091 (registered on December 10, 2013) Japanese Registered Patent No. 4860253 (registered on November 11, 2011)

An object of the present invention is to provide an electron beam melting device capable of melting a metal having a high melting point while controlling a melting speed.

In addition, an object of the present invention is to provide an electron beam melting apparatus capable of easily removing impurities and growing an ingot of high purity.

The object of the present invention is not limited to the above-mentioned object, and other objects not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the above problem, the present invention includes an electron gun for generating an electron beam, a first coil for focusing the electron beam emitted from the electron gun, and a second coil for secondarily focusing the firstly focused electron beam, an electron beam chamber for heating a high-melting-point metal raw material by irradiating electron beams focused on two coils; a melting chamber including a mold for forming an ingot by cooling the molten metal in which the high-melting-point metal raw material is melted, and a raw material supply unit supplying the high-melting-point metal raw material into the mold; And an ingot chamber having an ingot puller for drawing the ingot from the mold and growing the ingot; including, adjusting the current applied to the first coil and the current applied to the second coil and irradiating the high melting point metal raw material It is possible to provide an electron beam melting device characterized in that the shape of the electron beam to be adjusted.

The electron beam irradiated onto the high melting point metal material may have a ring shape or a circular shape.

A current applied to the first coil may be greater than a current applied to the second coil, and an electron beam irradiated onto the high-melting point metal material may have a circular shape.

The difference between the current applied to the first coil and the current applied to the second coil is 10% or less of the current applied to the first coil or the current applied to the second coil, and irradiated on the refractory metal raw material The shape of the electron beam may be a ring shape.

As the ratio of the current applied to the first coil to the current applied to the second coil increases, a cross-sectional area of the circular electron beam irradiated onto the refractory metal source may increase.

The electron beam melting device may control the current applied to the first coil and the second coil or the number of turns of the first coil and the second coil, and adjust the surface temperature of the high-melting point metal raw material irradiated with the electron beam. there is.

The ingot puller may include a support plate located inside the mold and supporting an ingot formed by blocking an opening in the lower portion of the mold, and a drawing driver configured to draw the ingot while moving the support plate downward.

A dummy member made of the same material as the ingot may be interposed between the high melting point metal raw material and the support plate.

The inside of the mold or the support plate may further include a cooling means for cooling the mold or the support plate.

An electron beam melting apparatus according to an embodiment of the present invention includes an electron beam chamber including a first coil and a second coil for focusing electron beams, adjusting the current applied to each coil, and controlling the electron beam irradiation on the high melting point metal raw material. It has the advantage of being able to melt while controlling the dissolution rate by adjusting the shape. In addition, impurities can be easily removed during melting of high melting point metal through electron beam melting, and thus there is an effect of growing into a high-purity ingot.

1 is a cross-sectional view showing an electron beam melting apparatus according to an embodiment of the present invention;
2 is a graph showing the magnetic field analysis results of the first coil and the second coil of the electron beam melting device according to an embodiment of the present invention;
3 is a graph showing modeling of electron beam formation of an electron beam melting device according to an embodiment of the present invention;
4 is a graph showing electron beam heat source analysis of an electron beam melting device according to an embodiment of the present invention;
5 is a photograph showing electron beam shape control of an electron beam melting device according to an embodiment of the present invention;
6 is a photograph showing the melting state of a high melting point metal material according to the electron beam output intensity of the electron beam melting device according to an embodiment of the present invention;
7 is a graph showing the melting depth and melting temperature of a high melting point metal material according to the electron beam output intensity of the electron beam melting device according to an embodiment of the present invention;
8 is a graph showing the melting ratio of the high melting point metal material according to the electron beam power density of the electron beam melting device according to an embodiment of the present invention;
9 is a graph showing the melting depth of a high melting point metal material according to the electron beam power density of the electron beam melting device according to an embodiment of the present invention;
10 is a graph showing the ingot growth rate of a high melting point metal material according to the electron beam power density of the electron beam melting device according to an embodiment of the present invention;
11 is a graph showing the melting depth of a high melting point metal material according to the power density of the electron beam when the electron beam of the electron beam melting device according to an embodiment of the present invention rotates;
12 is a graph showing the temperature distribution of the electron beam according to the number of turns of the first coil and the second coil of the electron beam melting apparatus according to an embodiment of the present invention;
13 is a graph showing the temperature distribution of the electron beam according to the applied current of the first coil and the second coil of the electron beam melting device according to an embodiment of the present invention;
14 is a view showing a first coil or a second coil of an electron beam melting device according to an embodiment of the present invention;
15 is a diagram showing particle trajectories of electron beams according to the number of windings of the first coil or the second coil of the electron beam melting apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention may be embodied in other forms without being limited to the embodiments described below. Also, in the drawings, the lengths and thicknesses of layers and regions may be exaggerated for convenience. Like reference numbers indicate like elements throughout the specification.

1 is a cross-sectional view showing an electron beam melting device according to an embodiment of the present invention, FIG. 2 is a graph showing magnetic field analysis results of a first coil and a second coil of the electron beam melting device according to an embodiment of the present invention, FIG. A graph showing electron beam formation of an electron beam melting apparatus according to an embodiment of the present invention. FIG. 4 is a graph showing electron beam heat source analysis of an electron beam melting apparatus according to an embodiment of the present invention. FIG. 6 is a photograph showing the electron beam shape control of the electron beam melting device, Figure 6 is a photograph showing the melting state of the high melting point metal material according to the electron beam output intensity of the electron beam melting device according to an embodiment of the present invention, Figure 7 is a photograph showing the embodiment of the present invention 8 is a graph showing the melting depth and melting temperature of the high melting point metal material according to the electron beam output intensity of the electron beam melting device according to the embodiment of the present invention. 9 is a graph showing the melting depth of a high melting point metal material according to the electron beam power density of the electron beam melting apparatus according to an embodiment of the present invention, Figure 10 is the electron beam output of the electron beam melting apparatus according to an embodiment of the present invention A graph showing the ingot growth rate of the high melting point metal material according to the density, Figure 11 is a graph showing the melting depth of the high melting point metal material according to the power density of the electron beam when the electron beam of the electron beam melting device according to an embodiment of the present invention rotates 12 is a graph showing the temperature distribution of the electron beam according to the number of turns of the first coil and the second coil of the electron beam melting device according to an embodiment of the present invention, and FIG. 13 is a graph showing the electron beam melting device according to the embodiment of the present invention. A graph showing the temperature distribution of the electron beam according to the applied current of the first coil and the second coil. FIG. 14 is a diagram showing the first coil or the second coil of the electron beam melting apparatus according to an embodiment of the present invention. FIG. It is a diagram showing the particle trajectory of the electron beam according to the number of turns of the first coil or the second coil of the electron beam melting device according to the embodiment.

1 to 15, the electron beam melting device 1 according to an embodiment of the present invention includes an electron gun 130 that generates an electron beam, and a first coil 110 that focuses the electron beam emitted from the electron gun 130. ) and a second coil 120 for secondarily focusing the firstly focused electron beam, and irradiating the focused electron beam 10 from the second coil 120 to heat the high melting point metal raw material (M) electron beam chamber 100; A mold 210 for forming an ingot by cooling the molten metal in which the high melting point metal raw material M is melted, and a raw material supply unit 220 for supplying the high melting point metal raw material M into the mold 210. melting chamber 200; and an ingot chamber 300 including an ingot puller 310 that draws ingots from the mold 210 and grows the ingots, and the current applied to the first coil 110 and the second coil 120 ) and the shape of the electron beam 10 irradiated on the high melting point metal raw material M may be adjusted. The electron beam melting device 1 includes an electron beam chamber 100 including a first coil 110 and a second coil 120 for focusing the electron beam, and controls the current applied to each coil, thereby controlling the high melting point metal material. By controlling the shape of the electron beam 10 irradiated onto (M), there is an advantage in that melting can be performed while controlling the melting depth or the melting speed. In addition, it is possible to easily remove impurities when the high melting point metal M is melted through electron beam melting, and thus, there is an effect of growing an ingot of high purity.

In detail, the electron beam melting apparatus 1 according to an embodiment of the present invention may include an electron beam chamber 100, a melting chamber 200, and an ingot chamber 300, and the electron beam chamber 100, the melting chamber ( 200) or the ingot chamber 300 may be connected to a vacuum pump for a vacuum atmosphere. For example, the vacuum pump may be a turbo molecular pump or an oil diffusion pump, but is not limited thereto.

The electron beam chamber 100 includes an electron gun 130 that generates an electron beam, a first coil 110 that focuses the electron beam emitted from the electron gun 130, and a second coil that secondarily focuses the firstly focused electron beam ( 120), and the electron beam 10 focused on the second coil 120 may be irradiated to melt the high melting point metal raw material M. For example, the high melting point metal raw material M may be a metal having a melting point of 2000° C. or more, or one or more metals selected from Ti, Zr, Hf, V, Nb, Ta, Mo, and W, and may be provided in the form of scrap. can Also, as an example, the first coil 110 or the second coil 120 may be provided as a focus induction magnetic coil.

In the present invention, the output of the electron beam is determined by the voltage and current of the electron beam. The electron beam voltage is the absolute value of the cathode voltage that forms an electric field between the cathode and anode, and the electron beam current means the current value controlled by the voltage of the grid. .

The electron gun includes a cathode including a filament that generates and emits electrons, an anode installed at a predetermined distance in front of the cathode and accelerating electrons emitted from the cathode by forming an electric field with the cathode, and a cathode and It includes a grid installed between the anodes and controlling the amount of electron beam current by controlling the amount of electrons emitted from the cathode. With the anode grounded, a negative (-) voltage is applied to the cathode to form an electric field between the cathode and anode. By changing the voltage while applying a voltage lower than that of the cathode to the grid, the amount of current of the electron beam emitted from the electron gun can be controlled.

The radius of the coil may be 20 to 80 mm, preferably 25 mm. The number of coil windings may be 500 to 10,000 times, and the number of times may be adjusted according to the melting point of the high melting point metal raw material M, which is a melting object. In order to melt molybdenum (Mo), the number of windings of the first coil 110 may be 9000 to 10000 and the number of windings of the second coil 120 may be 5000 to 10000 based on an electron beam voltage of 35.5 kV and an electron beam current of 1 A.

By energizing the filament (cathode) of the electron gun, electrons are emitted from the filament, and the electrons fly toward the anode located below the filament and are accelerated downward. That is, electrons emitted from the filament may be accelerated by absorbing kinetic energy in an electric field applied between the filament and the anode, and in this case, the electric field may be generated by a voltage of about 30 to 70 kV. By changing the grid voltage, the amount of current of the electron beam emitted from the electron gun can be adjusted, and the electron beam current can range from 0.5 to 2.0 A.

The electron beam melting device 1 adjusts the current applied to the first coil 110 and the current applied to the second coil 120 to adjust the shape of the electron beam 10 irradiated onto the high melting point metal raw material M. It can be adjusted as shown in FIG. 5 . By controlling the current applied to the first coil 110 and the current applied to the second coil 120, the electron beam 10 irradiated onto the high melting point metal raw material M may have a ring shape or a circular shape. can That is, the electron beam 10 irradiated on the high melting point metal raw material M by concentrating or dispersing the electrons emitted from the electron gun 130 by changing the magnetic field by controlling the current applied to the coil has a ring shape or a circular shape. can

The magnetic flux density (B) is as shown in Equation 1 below when the vacuum permeability (Tm/A) is μ ₀ , the coil radius (m) is R, the coil current (A) is I, and the number of turns of the coil is n.

-------------- 식(1)

-------------- Equation (1)

For example, the magnitude of the current applied to the first coil 110 or the second coil 120 can be controlled in the range of 0.2A to 0.8A, and the first coil 110 and the second coil 120 As shown in FIG. 2, the magnetic field analysis result when n is 1000 and R is 0.04 is 1.03 × 10 ^-4 T around the first coil 110, and 6.03 × 10 ^-5 T. If a current of about 700 mA is applied to the first coil 110 and a current of about 220 mA is applied to the second coil, modeling of the electron movement path, that is, the formation of the electron beam 10 is shown in FIG. 3, and the high melting point metal raw material (M) When the electron beam 10 irradiated to is controlled to have a diameter of about 2 cm, the analysis of the electron beam heat source is shown in FIG. 4 .

In the electron beam melting device of the present invention, the electron beam acceleration voltage is 25 to 35.5 kV, the electron beam current is 0.5 to 2.0 A, the number of windings of the first coil is 5,000 to 10,000 times, the coil radius of the first coil is 65 to 70 mm, and the second coil The number of winding may be 5,000 to 10,000 times, and the coil radius of the second coil may be 75 to 85 mm.

The shape of the electron beam can be adjusted by controlling the current applied to the first coil 110 and the second coil 120 or the number of turns.

When the current A1 applied to the first coil 110 is greater than the current A2 applied to the second coil 120, the shape of the electron beam 10 irradiated onto the high melting point metal raw material M is It may have a circular shape. Furthermore, when the current A1 applied to the first coil 110 is 450 mA or more and 720 mA or less, and the current A2 applied to the second coil 120 is 225 mA or more and 320 mA or less, the high melting point metal raw material (M ) The shape of the electron beam 10 irradiated onto may be a circular shape. Preferably, if the ratio of the current A1 applied to the first coil 110 and the current A2 applied to the second coil 120, A1/A2 is 2.5≤A1/A2≤3.2, the high melting point metal raw material The shape of the electron beam 10 irradiated onto (M) may be circular.

In addition, as the ratio of the current A1 applied to the first coil 110 to the current A2 applied to the second coil 120 increases, the circular electron beam irradiated onto the high melting point metal material The cross-sectional area may be increasing.

When the current A1 applied to the first coil is greater than or equal to 210 mA and less than 450 mA, and the current A2 applied to the second coil is greater than or equal to 200 mA and less than or equal to 240 mA, the electron beam 10 irradiated onto the high melting point metal material M ) The shape of may be a ring shape. Preferably, when the ratio of the current (A1) applied to the first coil and the current (A2) applied to the second coil, A1/A2 is 0.9≤A1/A2≤1.5, the high melting point metal raw material (M) phase The shape of the electron beam 10 irradiated onto may be a ring shape. More preferably, the difference (A2-A1) between the current A1 applied to the first coil 110 and the current A2 applied to the second coil 120 is the current A1 applied to the first coil 110. ) or 10% or less of the current A2 applied to the second coil.

Table 1 and FIG. 5 show the area (area) and shape of the electron beam 10 irradiated to the high melting point metal raw material M with respect to the current applied to the first coil 110 and the second coil 120. At this time, the electron beam acceleration voltage is 35.5 kV, the electron beam current is 0.5 to 2.0 A, the number of winding of the first coil is 5,000 to 10,000, the coil radius of the first coil is 67 mm, the number of winding of the second coil is 5,000 to 10,000, The coil radius of the second coil is 80 mm. For example, in all metal materials having a high melting point, the electron beam current may be 0.05A to 2.0A.

Applied current of the first coil A1 [mA] Applied current of the second coil A2 [mA] electron beam area
[cm 2 ] Test Example 1 210 225 25.38 test example 2 710 225 26.63 Test Example 3 740 475 0.99

Referring to FIG. 5, the shape of the electron beam 10 irradiated on the refractory metal source M of Test Example 1 is (a), the electron beam irradiated on the refractory metal source M of Test Example 2. The shape of (10) is the same as (b), and the shape of the electron beam 10 irradiated on the high-melting point metal raw material M of Test Example 3 is the same as (c), and the electron beam according to the current applied to each coil. It can be seen that the shape of

When the number of windings (N1) of the first coil 110 is 5,000 to 10,000 times and the number of windings (N2) of the second coil 120 is 5,000 to 10,000 times, the electron beam irradiated on the high melting point metal raw material (M) The shape of (10) may be circular. Preferably, when the ratio of the number of windings (N1) of the first coil 110 and the number of windings (N2) of the second coil 120, N1/N2, is 0.5≤N1/N2≤2, the high melting point metal raw material (M ) The shape of the electron beam 10 irradiated onto may be a circular shape.

When the number of windings (N1) of the first coil 110 is 500 to 1,000 times and the number of windings (N2) of the second coil 120 is 8,000 to 10,000 times, the electron beam irradiated on the high melting point metal raw material (M) The shape of (10) may be a ring shape. Preferably, if the ratio of the number of windings (N1) of the first coil 110 and the number of windings (N2) of the second coil 120, N1/N2, is 0.06≤N1/N2≤0.1, the high melting point metal raw material (M ) The shape of the electron beam 10 irradiated onto may be a ring shape.

Referring to FIG. 15 showing the particle trajectory of the electron beam according to the number of turns of the first coil or the second coil of the electron beam melting apparatus, it can be seen that the shape of the electron beam changes according to the number of turns of the coil. For example, when the electron beam acceleration voltage is 20 kV, the electron beam current is 1 A, the number of turns of the first coil is 1000, and the number of turns of the second coil is 10,000, the shape of the electron beam is ring-shaped (a in FIG. 15). When the electron beam acceleration voltage is 20 kV, the electron beam current is 1 A, and the number of turns of the first coil is 5000 and the number of turns of the second coil is 10,000, the shape of the electron beam may be circular (b in FIG. 15).

The electron beam 10 rotates in the mold and may be irradiated onto the high melting point metal raw material M. In particular, it can rotate in a circular motion within a set radius.

6 shows the melting state of the high melting point metal material when the electron beam is irradiated without rotating. 6 (a) shows the molybdenum melting results when the output of the electron beam 10 generated from the electron gun 130 is 14.2 kW, (b) is 17.75 kW, and (C) is 21.3 kW. , FIG. 7 is a result of heat transfer analysis for molybdenum temperature distribution, and the distance represents the molten distance (melting depth) from the top to the bottom based on the cut surface of the central portion of the high melting point metal raw material (M). When comparing FIG. 6 and FIG. 7, it can be seen that the heat transfer analysis result (FIG. 7) coincides with the experimental value (FIG. 6). That is, it can be confirmed that the output of the electron beam capable of realizing the melting point of molybdenum of about 2600 degrees or higher when the electron beam rotation is not applied is 17.75 kW and 21.3 kW. At this time, the diameter of the electron beam irradiated to the high melting point metal raw material M is 50 mm.

As an example, when the electron beam rotation is not applied and the electron beam current is 0.4A (14.2kW), 0.5A (17.75kW), and 0.6A (21.3kW) at an acceleration voltage of 35.5kV, the melting ratio of molybdenum to the electron beam irradiation time, The melting depth of molybdenum for electron beam power density and the growth rate of molybdenum ingot for electron beam power density were tested.

8 shows the melting ratio of molybdenum in two cases where the electron beam current is 0.5A (17.75kW, 0.67kW/cm ² ) and 0.6A (21.3kW, 0.80kW/cm ² ) at an acceleration voltage of 35.5kV when electron beam rotation is not applied. it is shown The melting ratio may be derived by calculating the volume of the molten sample relative to the total volume of the sample. When an electron beam having a power density of 0.80 kW/cm ² is irradiated to the molybdenum material for 10 minutes, about 23% of the material is melted, so it can be seen that complete dissolution occurs when irradiated for 50 minutes. Therefore, it is possible to determine the time required for complete melting of the high melting point metal raw material M according to the power density of the electron beam.

Referring to FIG. 9 (without electron beam rotation), the depth at which molybdenum is dissolved can be known according to the power density of the electron beam and the irradiation time of the electron beam. As a result, the volume of molybdenum that can be supplied to the mold can be determined according to the power density of the electron beam. You can figure it out. That is, the input amount of the high melting point metal raw material M may be set according to the power density of the electron beam. In this case, it can be expected that the rate of increase in the melting depth according to the increase in the power density of the electron beam will remain at a constant value (saturation), which means that vaporization also occurs along with the melting of the high melting point metal above a certain power density .

Referring to FIG. 10 (electron beam rotation not applied), it can be seen that the growth rate of the ingot increases as the power density of the electron beam increases. However, as shown in FIGS. 8 and 9, the melting ratio according to the irradiation time of the electron beam tends to remain at a constant value (saturation), and it can be seen that the melting depth increase pattern decreases even when the power density of the electron beam increases. Therefore, it can be seen that it is desirable to set the power density of the electron beam to a predetermined value or less.

When the electron beam is rotated and irradiated within a set radius, see FIG. 11 showing the melting depth of molybdenum (Mo), which is the high melting point metal raw material (M), according to the power density of the electron beam heat source irradiated to the high melting point metal raw material (M) Then, in order to melt the same depth, it can be seen that the power density when electron beam rotation is applied is 1.25 to 2.5 times greater than the power density when electron beam rotation is not applied. At this time, the melting depth y of molybdenum (Mo) with respect to the size x of the electron beam heat source has a linear relationship as shown in Equation 2 below, and can represent the relationship between the electron beam energy and the melting depth.

y=0.3x-0.3 (R ² =1) -------- Equation (2)

In this case, the electron beam may have an output state of 17 to 54 kW. That is, when the electron beam is rotated and irradiated, as described above with reference to FIGS. 6 and 7, more than twice the output (more than twice as much electron beam current) is required as compared to melting the high melting point metal raw material M by fixing the electron beam. can know

Impurity Concentration (PPM) Mopurity (%) Rating K Fe Al Ti W Ca C O Non-EBM 41.5 1.5 269.0 12.7 165.5 565.9 27.3 482.6 99.84 2N8 35.5kV, 0.5A 22.0 - 148.9 8.4 149.6 156.1 13.6 8.4 99.95 3N5 35.5kV, 1.0A 17.9 - 94.18 7.014 147.2 119.47 13.2 8.2 99.96 3N6 35.5kV, 1.5A 15.15 - 94.15 4.521 146.6 112.2 13.1 8.1 99.991 4N1

Table 2 shows the impurity content and purity of molybdenum according to each electron beam output state while melting molybdenum by rotation of the electron beam. It can be seen that even in the case of 35.5 kV and 0.5 A having a relatively low output intensity, the impurity concentration is reduced, and when the output intensity is increased, the impurity concentration is further reduced and the purity of molybdenum is further improved. In addition, since oxygen has an excellent concentration reduction effect compared to other impurities, the generation of oxides can be further prevented during ingot growth of the high melting point metal raw material M using the electron beam melting device 1, and high purity high melting point metal It can be seen that ingots can be produced.

The electron beam melting device 1 controls the current applied to the first coil 110 and the second coil 120 or the number of turns of the first coil 110 and the second coil 120, (10) may be to adjust the surface temperature of the high melting point metal raw material (M) to be irradiated.

As described above, in the present invention, the output of the electron beam is determined by the voltage and current of the electron beam. The voltage is the absolute value of the voltage of the cathode that forms an electric field between the cathode and anode, and the current refers to the current value controlled by the grid. do. That is, the electron gun 130 includes a cathode including a filament that generates and emits electrons, an anode installed at a predetermined distance in front of the cathode and forming an electric field with the cathode to accelerate electrons emitted from the cathode, and the cathode and the anode. and a grid installed between the cathode and controlling the amount of electron beam current by controlling the amount of electrons emitted from the cathode. With the anode grounded, a negative (-) voltage is applied to the cathode to form an electric field between the cathode and anode, and by applying a voltage lower than the cathode to the grid and changing the voltage, the amount of current of the electron beam emitted from the electron gun can be controlled. there is.

When adjusting the number of windings of the first coil 110 and the second coil 120 and controlling the surface temperature of the high melting point metal material M to which the electron beam 10 is irradiated, for example, the high melting point metal An acceleration voltage of 35.5 kV and an electron beam current of 1 A may be set in the electron gun 130 to heat molybdenum as a raw material M above its melting point. And, when the number of windings of the first coil 110 is 5000 to 10000 times and the number of windings of the second coil 120 is adjusted between 5000 and 10000 times, the surface temperature of the high melting point metal raw material M has a temperature distribution as shown in FIG. can have,

In addition, when adjusting the current applied to the first coil 110 and the second coil 120 and adjusting the surface temperature of the high melting point metal raw material M to which the electron beam 10 is irradiated, for example, The number of turns of the first coil 110 and the second coil 120 may be the same, and the electron gun 130 may set an acceleration voltage of 35.5 kV and an electron beam current of 1 A. And, when the current flowing through the first coil 110 is 0.65 to 0.7A and the current flowing through the second coil 120 is 0.2 to 0.35A, the surface temperature of molybdenum (Mo), which is a high melting point metal raw material (M), is shown in FIG. It can have a temperature distribution like 13. This can be said to be a result corresponding to Test Example 2 in Table 1 above.

The melting chamber 200 coupled to the lower part of the electron beam chamber 100 cools the molten metal in which the high melting point metal raw material M is melted to form an ingot, and the mold 210 is solidified into the mold 210. It may include a raw material supply unit 220 for supplying a melting point metal raw material M, and the ingot chamber 300 is coupled to the melting chamber 200 and draws the ingot from the mold 210 to grow the ingot. A puller 310 may be provided. Preferably, the raw material supply unit 220 for supplying the high melting point metal material M into the mold 210 supplies the raw material at a rate corresponding to the melting rate of the high melting point metal material M by the electron beam 10. .

For example, the mold 210 may be formed of a metal material having excellent thermal conductivity, such as copper, and may have a cylindrical shape with openings formed at the top and bottom. The support plate 311 may also be formed of a metal material having excellent thermal conductivity such as copper. The mold 210 not only forms an ingot by cooling and solidifying the molten high-melting point metal melted and refined by the electron beam 10, but also functions as a heat-resistant container when the high-melting point metal raw material M is melted by the electron beam 10 can also have

The ingot puller 310 includes a support plate 311 located inside the mold 210 and supporting an ingot formed by blocking an opening at the bottom of the mold 210, and moving the support plate 311 downward to remove the ingot. It may include a drawing drive unit 315 for drawing out. That is, by pulling down the support plate 311 blocking the lower opening of the mold 210 at a predetermined speed, the cylindrical ingot in which the high-melting point molten metal is solidified can be continuously cast.

Furthermore, the inside of the mold 210 or the support plate 311 may further include cooling means 230 or 330 for cooling the mold 210 or the support plate 311 . That is, the high melting point metal raw material M is melted and refined in the mold 210 by the electron beam 10, cooled by a cooling means for cooling the mold 210 or the support plate 311, and ingots can be grown. there is. By cooling the metal material constituting the mold 210 and the support plate 311, alloying between the mold 210 wall surface or the surface of the support plate 311 and the high-melting point metal is prevented, and separation from the mold wall surface when the ingot is moved downward can be easily For example, the temperature of the cooling means (230, 330) may be maintained at 18 to 20 degrees, and cooling may be achieved through circulation of distilled water.

In addition, in order to prevent oxidation of the high melting point metal ingot after the electron beam 10 irradiation process, the ingot chamber 300 and the melting chamber 200 maintain a vacuum degree of 10 ⁻⁶ torr or less for 24 hours or more, and the high melting point metal ingot can be cooled

A dummy member 320 made of the same material as the ingot may be interposed between the high melting point metal raw material M and the support plate 311 . In this case, the dummy member 320 may be a thin plate-like body made of the same material as the ingot, and the lower part of the molten metal having a high melting point is cooled and solidified by the mold 210, and is integrated with the dummy member 320. so that an ingot can be formed.

Due to the rotation of the electron beam 10, the molten metal region 20 of the high melting point metal material M is evenly distributed throughout the inside of the mold 210, and the drawing driver 315 moves at a low speed enough to prevent the molten high melting point metal from being stirred. , For example, the support plate 311 rotates in the range of 0.2 revolutions/minute to 2 revolutions/minute, and the ingot can grow while moving downward. In addition, when the high melting point metal material M is supplied, the high melting point metal material M may be supplied while rotating the support plate 311 so as to be properly dispersed in the rotational direction.

An electron beam melting apparatus 1 according to an embodiment of the present invention includes an electron beam chamber 100 including a first coil 110 and a second coil 120 for focusing an electron beam 10, and applying the electron beam 10 to each coil. It has the advantage of being able to melt while controlling the dissolution rate by controlling the current and controlling the shape of the electron beam 10 irradiated on the high melting point metal raw material M. In addition, it is possible to easily remove impurities when melting high-melting point metal through electron beam melting, and thus, there is an effect of growing an ingot of high purity.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

One; Electron Beam Melting Machine
10; electron beam
100; electron beam chamber
110; 1st coil
120; 2nd coil
130; electron gun
200; melting chamber
210; Mold
220; Raw material supply department
230, 330; cooling means
300; ingot chamber
310; ingot puller
311; support plate
315; Pull drive unit
320; dummy absence
M; high melting point metal raw material

Claims (9)

An electron gun that generates an electron beam, a first coil that focuses the electron beam emitted from the electron gun, and a second coil that secondarily focuses the firstly focused electron beam, wherein the second coil irradiates the focused electron beam to obtain high an electron beam chamber for heating the melting point metal source;
a melting chamber including a mold for forming an ingot by cooling the molten metal in which the high-melting-point metal raw material is melted, and a raw material supply unit supplying the high-melting-point metal raw material into the mold; and
Including; an ingot chamber having an ingot puller for drawing the ingot from the mold and growing the ingot;
The electron beam melting apparatus characterized in that the current applied to the first coil and the current applied to the second coil are adjusted and the shape of the electron beam irradiated on the high melting point metal raw material is controlled.
According to claim 1,
The electron beam melting device characterized in that the electron beam irradiated on the high melting point metal material has a ring shape or a circular shape.
According to claim 1,
The current applied to the first coil is greater than the current applied to the second coil,
The electron beam melting device, characterized in that the shape of the electron beam irradiated on the high melting point metal raw material is circular.
According to claim 1,
The difference between the current applied to the first coil and the current applied to the second coil is 10% or less of the current applied to the first coil or the current applied to the second coil,
The electron beam melting device, characterized in that the shape of the electron beam irradiated on the high melting point metal raw material is a ring shape.
According to claim 3,
An electron beam melting apparatus, characterized in that, as the ratio of the current applied to the first coil to the current applied to the second coil increases, the cross-sectional area of the circular electron beam irradiated on the high melting point metal source increases.
According to claim 1,
The electron beam melting device controls the current applied to the first and second coils or the number of windings of the first and second coils, and controls the surface temperature of the high melting point metal raw material irradiated with the electron beam. Electron beam melting device to.
According to claim 1,
The ingot puller includes a support plate located inside the mold and supporting an ingot formed by blocking the opening of the lower part of the mold, and a drawing driver for drawing the ingot while moving the support plate downward. Electron beam melting device, characterized in that .
According to claim 7,
An electron beam melting device, characterized in that a dummy member made of the same material as the ingot is interposed between the high melting point metal raw material and the support plate.
According to claim 7,
The inside of the mold or the support plate further comprises a cooling means for cooling the mold or the support plate.

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