JP2006049250A - Heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating treatment device for forming a uniform alloy or uniform dispersion body of metals without any complicated process with a large difference of specific gravity from each other or metal and ceramic by preventing separation of above materials apt to be caused due to the difference of specific gravity. <P>SOLUTION: The induction heating device can apply a heat treatment on a material to be processed under practically zero gravity by applying a field of force in an opposite direction of gravitational force on the material to be processed by supplying an alternating current to a material to be processed in a rectangular direction in a horizontal plane in compliance with an alternating magnetic field applied on the heating device so as to change the direction in conformity with the alternating magnetic field. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention mainly relates to an induction heating apparatus for melting metal, and produces a metal composed of two or more components having different specific gravities, an alloy in which metal and nonmetal are uniformly distributed, or a metal body in which particles are uniformly dispersed. It is related with the apparatus for.

In the production of alloys and the production of particle-dispersed metals, the difference in specific gravity is small, and in the case of metals having close melting points or alloys of metal and particles, a homogeneous alloy can be obtained in combination with the stirring action when melting by induction heating. When melting the alloy components, if the melting points of both are greatly different, an alloy with a different quantitative ratio is prepared in advance, and a certain degree of homogeneity can be achieved by melting the alloys together. Then, such a technique is often taken. However, even in such a case, there is a difference in specific gravity between alloy components, and if it is large, even if the alloy powders are remelted, separation due to the difference in specific gravity occurs during melting, rather than simple mixing and melting. Although it was somewhat better, there was a problem that the composition changed depending on the part.

Also, when one is soluble but one is difficult to dissolve, or when creating a particle-dispersed metal or alloy with improved function by dispersing fine particles in the metal, it is necessary if the specific gravity of the particles and the metal is close Accordingly, the surface of the particles can be coated with the metal in advance so as to improve the wettability of the particles with the metal, or even if mixed as it is, it can be dissolved with stirring in the induction dissolution. An alloy having dispersed particles can be obtained relatively easily. However, if the alloy components have a large difference in specific gravity and one of them is particles, there is a high possibility of separation during melting depending on the specific gravity difference. In particular, in the case of platinum, iridium, tungsten or tantalum, the specific gravity is 20 g / ml or more, whereas when ceramic fine powder is dispersed in this, the specific gravity of the ceramic is 10 g / ml or less, usually 3 to 7 g / ml. Because there are many, the difference in specific gravity is so large that it is necessary to make an alloy, or to add ceramic particles to a white metal such as platinum or iridium or tungsten and disperse them to obtain a uniform alloy or mixture. It was difficult. In other words, the powder and particles that must be mixed floated, and even with high-frequency induction melting with a stirring function, it was difficult to be uniform.

Recently, platinum with dispersed particles such as zirconia that require high-temperature strength is used as a melting crucible for the production of liquid crystal base glass, which has recently been attracting attention. A special method is used because separation occurs due to the difference in specific gravity and cannot be dispersed. That is, as in the atomizing method, a mother alloy powder containing powder in a metal is prepared and sintered (Japanese Patent Laid-Open No. 06-336631). Alternatively, platinum is supported by a method in which zirconium hydroxide is supported in water around platinum metal powder, sintered, and forged (Japanese Patent Laid-Open No. 2002-012924). In general, a mother alloy powder prepared by powder metallurgy is formed into a metal body while minimizing the porosity by HIP (high temperature isotropic pressing). These powder sintering, forging, and HIP methods do not completely dissolve the metal, so a sufficient filling rate cannot be obtained, and even this is not guaranteed to be completely uniform, and is not necessarily uniform. The point was left.
Many documents and patents have been issued regarding the use of the electromagnetic induction method for melting metals, but all relate to heating efficiency and the like.
Japanese Patent Laid-Open No. 06-336631 JP2002-012924

It is an object of the present invention to provide a heat treatment apparatus for forming a uniform alloy or a uniform dispersion without complicated processes for separation due to a difference in specific gravity, which is likely to occur between metals having a large specific gravity difference or between metal and ceramic alloys. .

In the present invention, an alternating current is passed through the material to be processed so that the direction changes in synchronization with the alternating magnetic field in the direction perpendicular to the horizontal plane in response to the alternating magnetic field applied to the induction heating device. An induction heating device capable of substantially heat-treating the material to be treated under a weightless condition by applying a force field, wherein the alternating magnetic field in the induction heating device is synchronized with the alternating magnetic field in a direction perpendicular thereto. By applying an alternating current, a force field that complies with the so-called Fleming's law is formed and applied in the direction opposite to the gravity so that the gravity is substantially canceled while the workpiece is being processed. It became possible to obtain a uniform alloy or dispersion by stirring the melt to be treated by induction heating.

In other words, the present invention uses Fleming's left-hand rule so that force is generated in the direction opposite to gravity, and is applied by a magnetic field while approaching zero gravity by applying almost the same force as gravity against the gravitational field. The material to be treated is heated by the induced current, and the material to be treated is melted together with other heat sources as necessary, and the material to be treated is homogenized by the stirring action of the melt accompanying the induced current. In other words, the high-frequency heating method is often used for high-temperature heating and melting of the conductor, and this is achieved by a high-frequency coil that causes current to flow through the body to be processed and generate heat. Usually, by making the structure so as not to let this electric or magnetic field escape, heat is efficiently converted into heat. Here, an alternating magnetic field is applied and this becomes heat, but apart from this, a current flows in synchronization with the perpendicular direction, and apart from melting, the so-called Fleming's left-hand rule is A force is applied in the direction. In the case of high-frequency induction heating, the magnetic field used for this is an alternating magnetic field, so the direction of the magnetic field is always reversed. By synchronizing and reversing the electric field applied to this, it is possible to always apply a force in one direction. Thus, if it balances with gravity, melt | dissolution in a substantially weightless state will be attained.

In the induction heating apparatus used here, a coil is placed in a direction perpendicular to the direction of gravity, and a melt (a precursor of the melt) is passed through the coil. On the other hand, an electric current is passed through the melt in synchronization with the magnetic field in a direction perpendicular to both the flow direction and the gravity direction. The induction heating is preferably performed by a high-frequency method that is normally performed, but the frequency is preferably 50 to 500 Hz. This is because an alternating current flows through the object to be processed in synchronization with induction heating, but depending on the object to be processed, depending on the capacitance, if the frequency increases, it will not follow the current direction even if the current direction is changed. In the case of metal, since the capacity is relatively small, it is considered that there are few problems. As a result, a force of almost the same magnitude as the gravity field can be generated in the direction opposite to the gravity field in the direction of the gravity field. Since the induced magnetic field and the current field synchronized with this need to be changed according to the specific gravity of the object to be processed and the required temperature, they must be synchronized, but their strength must be changed independently. is there.

The object to be processed is dissolved therein. The material to be treated may be placed in a batch in these coils, or may be melted or semi-dissolved outside, or processed continuously in powder form and continuously taken out as a semi-melt. May be. In any case, the dissolved portion can basically be dissolved while being stirred under conditions close to weightlessness. An example is shown in FIG. That is, there is a boat for current application in the center, and a coil for generating an induction magnetic field is placed outside the boat. This causes an induced magnetic field in the longitudinal direction of the boat. In addition, an electric field is generated by applying an electric current to the object to be processed by an electrode placed in the boat in parallel with the coil. Both the electric field and the magnetic field are high-frequency, and about 300 Hz for a normal metal. Of course, this frequency can be changed according to the condition of the object to be processed. In addition, since the directions of the electric field and the magnetic field are synchronized, the force formed by this is a direction perpendicular to the magnetic field and the electric field, and is opposite to the direction of gravity. Of course, this can also make a gradient material alloy by increasing the acceleration of gravity and giving a centrifugal action, but here we make a mixture or alloy in the zero gravity state by turning it in the opposite direction to gravity. Used for

For example, in the case of zirconia-dispersed platinum for melting liquid crystal base glass, the specific gravity of zirconium oxide is about 5 g / cc, whereas platinum has a very large difference of about 22 g / cc. As described above, it is not uniform. In such a case, when dissolved by the proposed process, platinum is stirred by an induced magnetic field, and zirconium oxide is uniformly dispersed therein. If this is cooled, platinum in which zirconium oxide is uniformly dispersed can be obtained. This process may be continuous or batch as described above.

As shown in FIG. 1, a ceramic flow path or boat for flowing or processing a material to be processed is placed in the center, and a high frequency coil for generating a magnetic field is placed around it. Further, two electrodes are placed in parallel with the axial direction of the magnetic field inside the boat or flow path for the material to be processed, and an electric current flows from the electrodes through the melt to form an electric field. This electrode is difficult to react with the object to be processed, has good electrical conductivity, needs to have sufficient heat resistance, and needs an oxidizing atmosphere for dissolving zirconia-dispersed platinum. It is effective to use iridium metal that partially dissolves but has little influence, or carbon in consideration of a certain amount of consumption. In FIG. 1 boat (3), metal components having greatly different specific gravity of the object to be processed and metals such as platinum and zirconia fine powder and ceramic body powder for dispersion are put. First, when a high frequency is applied to the surrounding induction coil (4), the metal in the boat is melted. Next, a current synchronized with the induction magnetic field is supplied to the electrode (5) in the boat. As a result, a force acts in the direction opposite to gravity, the melt of the object to be processed becomes substantially weightless, and platinum and zirconia particles having different specific gravity are dispersed with each other and the whole is made uniform by the stirring effect by induction heating. When it becomes uniform, it is cooled and solidified to obtain platinum in which zirconia is uniformly dispersed.

This process, which can dissolve metals in a substantially weightless manner or obtain a metal in which ceramic powders and fibers are uniformly dispersed, is useful not only for the production of various alloys in the metal alloy field, but also for metals and ceramics. It can be widely applied to the production of composites and reinforced alloys. For example, it is essential to use aluminum panels for automobiles that require weight reduction, and the increase in material rigidity due to reinforced platinum as described above. , More stable manufacturing glass substrate for liquid crystal. Etc. There are many useful uses from direct products to processed parts for making products.

It is a schematic diagram of this invention apparatus, and sectional drawing of the front and the plane was shown.

Explanation of symbols

1. Plan sectional view 2. Front sectional view 3. 3. Boat for object to be processed 4. Inductive magnetic field coil Electrode 6. 6. Direction of magnetic field Electric field direction8. Gravity 9. Fleming power

Claims (8)

Corresponding to the alternating magnetic field applied to the induction heating device, by passing an alternating current through the material to be treated so that the direction changes in the direction perpendicular to the alternating magnetic field, a force field in the opposite direction of gravity is applied. An induction heating apparatus capable of substantially heat-treating the material to be treated under substantially zero gravity. 2. The induction heating apparatus according to claim 1, wherein the alternating magnetic field is applied by a high frequency current. The induction heating apparatus according to claim 1 or 2, wherein the frequency of the high-frequency current is 50 to 500 Hz. 3. The induction heating apparatus according to claim 1, wherein the alternating electric field synchronized with the alternating magnetic field can be changed independently of the strength of the magnetic field. 4. The induction heating device according to claim 1, wherein the induction heating device is a metal melting device. 5. The induction heating apparatus according to claim 1, wherein the induction magnetic field is applied horizontally, and an electric field is applied in the same horizontal direction in a direction perpendicular to the magnetic field. 6. The induction heating apparatus according to claim 1, wherein the object to be processed is caused to flow in the axial direction of the magnetic field. The induction heating apparatus according to claim 1, further comprising a preheating mechanism for an object to be processed.

Images