JPH03191290A - Vacuum dissolving apparatus - Google Patents

Abstract

PURPOSE:To provide an alloy material of an arbitrary mixing ratio without lowering impurity removal efficiency by dissolving a low vapor pressure material in a host material dissolving chamber, dissolving a high vapor pressure material in a dissolution forming chamber, and guiding the material dissolved in the host material dissolving chamber into the dissolution forming chamber. CONSTITUTION:An alloy material from which impurities are to be removed is mounted on a material dissolving chamber 3, while a material liable to be vaporized in the alloy material (additive material) is mounted on material 13 side in a dissolution forming chamber 4. Pressure in the dissolution forming chamber is raised to higher pressure than the vapor pressure of the material 13. A dissolved material 12a contained in a hearth is heated and hence not solidified, and allowed to pass through a partition plate 2 part and introduced into the dissolution forming chamber 4. The materials 12a, 13a falling into a mold are cooled and gradually solidified by a water cooling pipe, and hence alloy ingot is formed by gradually lowering the bottom of the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a novel vacuum melting apparatus for melting alloy materials using an electron beam, laser light, or the like.

[Prior Art] Electron beam melting is used to remove impurities such as oxygen, nitrogen, hydrogen, and carbon from materials. Since this melting method is performed in a high vacuum, there is a problem that the melted material evaporates. Here, the lower the pressure in the melting chamber, the more completely impurities in the material can be removed. Lowering the pressure in the melting chamber in this way poses no problem when melting single-component materials, but when melting alloy materials, such as those containing manganese or chromium, mixed materials Of these, substances with high vapor pressure such as manganese and chromium evaporate during melting, resulting in a change in the mixing ratio.

[Problems to be Solved by the Invention] Therefore, in order to prevent this change in the mixing ratio, a method has been used in which the amount of evaporation is estimated and a substance that easily evaporates is added in a larger amount than the predetermined mixing ratio and dissolved. . However, even in this method, the amount of evaporation changes depending on the melting time and the melting atmosphere, so it is not possible to obtain an alloy with a desired mixing ratio. On the other hand, if the pressure in the melting chamber is lowered to suppress evaporation, changes in the mixing ratio can be alleviated, but on the other hand, the above-mentioned impurities remain in the feces caused by lowering the pressure in the melting chamber.

Therefore, the present invention has been made in view of this point, and an object of the present invention is to provide a vacuum melting apparatus that can obtain an alloy material with an arbitrary mixing ratio without reducing the efficiency of impurity removal. be.

[Means for Solving the Problems] In order to achieve the above object, the vacuum melting apparatus of the present invention separates the melting chamber kept in vacuum into a base material melting chamber and a melting and shaping chamber by a partition plate, and A means is provided for lowering the pressure in the material melting chamber than in the melting and shaping chamber, a means for melting a material with a low vapor pressure in the base material melting chamber, and a means for melting a material with a high vapor pressure in the melting and shaping chamber. and means for guiding the material melted in the base material melting chamber to the melting and forming chamber in order to mix together the materials melted in the base material melting chamber and the melting and shaping chamber, respectively, in the melting and shaping chamber. It is characterized by:

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

[Example J] The attached drawing is a cross-sectional perspective view showing a schematic configuration of an example of a vacuum melting apparatus according to the present invention.

In the figure, 1 is a melting chamber, which is separated into a base material melting chamber 3 and a melting and shaping chamber 4 by a partition plate 2 installed in the center thereof. The insides of the base material melting chamber 3 and the melting and shaping chamber 4 are connected to a high vacuum pump (not shown) via exhaust pipes 5g and 5b, and a variable displacement valve 6 is provided in the middle of the exhaust pipe 5b.
is installed. Furthermore, an introduction pipe 8 equipped with a flow rate regulating valve 7 for introducing an inert gas into the melting and shaping chamber 4 is connected thereto. Reference numeral 9 denotes a rectangular copper hearth that penetrates and is held by the partition plate 2 and is disposed astride the base material melting chamber 3 and the melting and shaping chamber 4. On the melting and shaping chamber 4 side of this hearth is a A sprue 10 is formed. Reference numeral 11 denotes a hollow copper mold placed directly below the sprue, and a bottom plate (not shown) that can be moved up and down is provided at the bottom of the mold. This mold 11 and the hearth 10 are cooled by a water cooling pipe.

Materials 12 and 13 are placed directly above the hearth 9 in the base material melting chamber 3 and directly above the mold 11 in the melting and shaping chamber 4, respectively, and each material is held by a moving mechanism not shown. 14 and 15 are electron beam EBI for melting each material 12 and 13 placed in the base material melting chamber 3 and the melting and shaping chamber 4;
Each electron beam generating means generates EB2, and each electron beam generating means has a built-in deflection system for deflecting the electron beam.

An example of a method for melting an alloy using a vacuum melting apparatus having such a configuration will be described in detail below.

First, an alloy substance from which impurities should be removed is attached to the material 12 side in the base metal melting chamber 3, and a substance (additive substance) that is easily evaporated in the alloy substance is attached to the material 13 side in the melting and shaping chamber 4. Attach. Next, the inside of the melting chamber 1 (base material melting chamber 3 and melt forming chamber 4) is evacuated to a desired high vacuum via the exhaust pipes 5a and 5b, and then the flow rate adjustment valve 7 is opened to inactivate. By introducing gas into the melt-forming chamber 4, the pressure of this melt-forming chamber is increased to a pressure higher than the vapor pressure of the material 13. In this state, first, while moving the material 12 by a certain amount, the electron beam generating means 14
The tip of this material is irradiated with an electron beam EBI generated from the material to melt it. The melted material 12a is stored in the hearth 9. At this time, the electron beam EBI irradiates the material 12 using the deflection system so that its scanning range is indicated by a solid line, and also irradiates the inside of the hearth 9, so the melted material 12a accommodated in the hearth is heated. It passes through the partition plate 2 portion without solidifying and is introduced into the melting and shaping chamber 4 side.

Further, at the same time as the electron beam FBI is generated, an electron beam EB2 is generated from the electron beam generating means 15 on the melting and shaping chamber 4 side.
Inside hearth 9 and mold 1, the scanning range is indicated by the dotted line.
Since the inside of the hearth is irradiated and heated, the melted material 12g introduced into the melting and shaping chamber side of the hearth does not solidify.

When the melted material 12a reaches the sprue of the hearth 9, it falls from the sprue and is accommodated in the mold 11. At the same time, the tip of the material 13 is moved by a certain amount directly above the mold 11, and is made to collide with the electron beam EB2 and melt, and as shown by reference numeral 13a, the tip of the material 13 is moved into the mold 11 along with the material 12g.
Let it fall within 1. Materials 12a and 13 that have fallen into the mold
Since a is cooled by a water-cooled vibrator and gradually hardens, an alloy ingot is formed by slowly pulling down the bottom of the mold. Note that when increasing the pressure in the melting and shaping chamber 4, instead of controlling only the flow rate regulating valve 7, this valve and the variable displacement valve 6 may be controlled simultaneously.

By doing this, the alloy material can be melted in a high vacuum, and the additive material that evaporated during the melting can be added in a high pressure atmosphere, so that the additive material evaporates when the additive is melted. can be prevented. As a result, impurities in the alloy material can be removed without changing the mixing ratio.

It should be noted that the above description is an example of the present invention, and many modifications can be made in implementing the present invention. For example, in the above embodiment, the alloy material was directly melted in the base material melting chamber maintained at a high vacuum, but the present invention is not limited to this. Alternatively, only the substance with a low pressure may be melted, and the other substance with a high vapor pressure may be melted in the melting and shaping chamber 4 having a high pressure. If you do it like this,
Alloy materials of high purity and arbitrary mixing ratios can be formed.

Further, in the above embodiment, the base material melting chamber and the melting and shaping chamber are formed by separating one melting chamber with a partition plate, but it is also possible to form each chamber separately and arrange the two adjacently. good.

Furthermore, in the above embodiments, an electron beam was used to melt each material in the base material melting chamber and the melting and shaping chamber. However, other methods such as laser beams, high frequency induction heating, resistance heating, etc. Known heating means may be used. At this time, when high frequency induction heating or resistance heating is used, it is necessary to heat the melted material contained in the hearth or the upper part of the crucible so that it does not solidify.

[Effects] As detailed above, according to the present invention, it is possible to provide a vacuum melting apparatus capable of obtaining an alloy material with an arbitrary mixing ratio without reducing the efficiency of removing impurities.

[Brief explanation of drawings]

The accompanying drawing is a cross-sectional perspective view showing a schematic configuration of an example of a vacuum melting apparatus according to the present invention. 1: Melting chamber 2: Partition plate 3: Base material melting chamber 4: Melting shaping chamber 5a, 5b: Exhaust pipe 6: Exhaust volume control valve 7: Variable flow rate valve 8: Inlet pipe 9: Copper hearth 10: Sprue 11: Crucible 12, 13: Material 14.15: Electron beam generating means 16: Ingot

Claims (1)

[Claims] The melting chamber kept in vacuum is separated into a base material melting chamber and a melting and shaping chamber by a partition plate, and the pressure in the base material melting chamber is lower than that in the melting and shaping chamber, so that the vapor pressure in the base material melting chamber is low. A means for melting a material is provided, a means for melting a material having a high vapor pressure in the melting and shaping chamber, and a means for melting the material melted in the base material melting chamber and the melting and shaping chamber, respectively, is provided in the melting and shaping chamber. A vacuum melting apparatus characterized in that a means is provided for guiding materials melted in a base material melting chamber to a melting and molding chamber for mixing together.