JP5878398B2 - Titanium melting equipment - Google Patents

Description

  The present invention is provided in an apparatus for continuously producing an ingot of titanium or a titanium alloy, and dissolves solid titanium or a titanium alloy as a raw material to form a molten metal, and then flows down the molten metal and injects it into a mold. About.

  As an apparatus for continuously producing an ingot of titanium, there is an apparatus described in Patent Document 1, for example. The apparatus described in Patent Document 1 is configured such that a solenoid coil is provided at a position surrounding a plasma electron gun, a hearth, and a mold, and a magnetic field is generated by the solenoid coil. Patent Document 1 states that by generating a magnetic field parallel to the plasma electron beam flow, the plasma electron beam can be focused, the beam density can be adjusted, and the molten state of the molten metal can be controlled. In addition, since magnetic stirring of the molten metal is performed on the water-cooled copper hearth, it is also described in Patent Document 1 that complete melting and refining of the raw material can be performed by complete mixing.

Japanese Patent Laid-Open No. 48-51835

  The present inventors are working on development of an apparatus for continuously producing an ingot of titanium (pure titanium) or a titanium alloy. Here, melting of solid titanium, which is a raw material, is performed by directly forming a raw material lump into a rod material or a block material and directly melting the raw material lump (sponge titanium, remaining material, scrap, etc.) ) And then melted with hearth. The method of directly melting the rod material or the like is costly for the molding of the raw material, and the dissolution rate is slow. Therefore, the method of introducing the raw material into the hearth and dissolving it in the hearth is more effective. The apparatus described in Patent Document 1 also employs a method in which a raw material is charged into a hearth and melted in the hearth.

  Here, since the dissolution rate of titanium is slow, when the raw material is melted with hearth, there is a risk that the undissolved raw material flows into the subsequent mold. In addition, there is a possibility that an operation trouble such as a raw material that cannot be melted sinks to the bottom of the hearth or adheres to the inner wall of the hearth.

  Such a concern also applies to the apparatus described in Patent Document 1. In the apparatus described in Patent Document 1, a solenoid coil is provided at a position that surrounds all the devices such as a plasma electron gun, a hearth, and a mold. The solenoid coil adjusts the beam density of the plasma electron beam. In addition, the magnetic stirring of the molten metal on the water-cooled copper hearth is performed by the solenoid coil. That is, the solenoid coil described in Patent Document 1 focuses on the adjustment of the plasma electron beam, and there is a concern that the molten metal may not be sufficiently stirred in the hearth. As a result, there is a possibility that an operation trouble such as the unmelted raw material flows into the mold, or the unmelted raw material settles on the bottom of the hearth or adheres to the inner wall of the hearth.

  This invention is made | formed in view of the said situation, The objective is to provide the titanium melting | dissolving apparatus provided with the structure which can fully stir the molten metal in a hearth than before.

  The present invention is provided in an apparatus for continuously producing an ingot of titanium or titanium alloy, and melts solid titanium or titanium alloy as a raw material by plasma heating to form a molten metal, which is then poured into a mold. It is a titanium dissolution apparatus. This titanium melting apparatus is charged with raw material solid titanium or titanium alloy, and is disposed close to the raw material melting hearth that melts the raw material by plasma heating to form a molten metal and the bottom surface of the raw material melting hearth, An electromagnetic stirrer for generating a swirling flow in the molten metal in the raw material melting hearth and stirring the molten metal.

  According to the titanium melting apparatus of the present invention, stirring of the molten metal in the hearth can be performed more sufficiently than before. As a result, it is possible to further prevent operational troubles such as the undissolved raw material flowing into the mold, or the undissolved raw material sinking to the bottom of the hearth or adhering to the inner wall of the hearth.

It is principal part explanatory drawing of the casting apparatus which comprises the titanium melt | dissolution apparatus which concerns on one Embodiment of this invention. It is a figure which shows the modification of the titanium melt | dissolution apparatus shown in FIG. It is a figure which shows the modification of the titanium melt | dissolution apparatus shown in FIG. It is a figure which shows the hearth for raw material melt | dissolution which concerns on a comparative example.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Configuration of titanium dissolution apparatus)
Fig.1 (a) is a top view of the principal part of the casting apparatus which comprises the titanium melting apparatus 1 which concerns on one Embodiment of this invention. FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. 1B is a cross-sectional view taken along the line BB in FIG.

  The titanium melting apparatus of the present invention is provided in a casting apparatus for continuously producing an ingot of titanium or a titanium alloy, and melts the solid titanium or titanium alloy as a raw material by plasma heating to make the molten metal flow down. It is a device that plays a role until it is injected into the mold.

  As shown in FIG. 1, the titanium melting apparatus 1 of the present embodiment includes a raw material melting hearth 2 and an intermediate hearth 3. The molten metal 53 in which the raw material 51 is melted by the plasma gas from the plasma torch 5 flows down from the raw material melting hearth 2 to the intermediate hearth 3 and flows from the intermediate hearth 3 into the mold 4. In this embodiment, as an example, porous sponge titanium (pure titanium) is used as a raw material.

  The hearth (2, 3), the mold 4 and the like are placed in a container called a chamber (not shown). Around the hearth (2, 3) and the mold 4 (inside the chamber) is an inert gas atmosphere such as argon gas or helium gas (filled with inert gas).

(Heart for melting raw materials)
The raw material melting hearth 2 is a bottomed holding container that plays a role of melting the raw material 51 (sponge titanium) by plasma heating to form a molten metal 53. The hearth 2 for melting the raw material is opened upward, and the inner peripheral wall and the outer peripheral wall are both square in plan view. As shown in FIG. 1A, when the length of one side of the inner peripheral wall of the raw material melting hearth 2 is L1, and the length of one side perpendicular thereto is L2, L1 = L2. Note that four corner portions (corner portions) of the inner peripheral wall of the raw material melting hearth 2 are chamfered in an arc shape. Thus, in the present invention, the square shape includes not only a square (a quadrilateral whose inner angles are all right angles and all the sides have the same length) but also a square whose corners (corner portions) are chamfered.

  The inner peripheral wall and / or outer peripheral wall of the raw material melting hearth 2 may be rectangular. When the inner peripheral wall of the raw material melting hearth 2 is rectangular, the ratio of the long side length to the short side length is preferably 1.5 or less. That is, in FIG. 1A, the value of L1 / L2 or L2 / L1 is preferably 1 or more and 1.5 or less. The square is a kind of rectangle.

  Further, the inner peripheral wall and / or the outer peripheral wall of the raw material melting hearth 2 may be an ellipse or a circle. When the inner peripheral wall of the raw material melting hearth 2 is an ellipse, the ratio of the major axis length to the minor axis length is preferably 1.5 or less. That is, the value of “major axis length” / “minor axis length” is preferably 1 or more and 1.5 or less. A circle is a kind of ellipse.

  Further, the inner peripheral wall and / or the outer peripheral wall of the raw material melting hearth 2 may be a polygon other than a quadrangle. An example of the polygon is an octagon. When the inner peripheral wall of the raw material melting hearth 2 is, for example, an octagon, a shape close to a regular octagon (a small aspect ratio) is preferable.

  The raw material melting hearth 2 is made of copper and cooled with water (the same applies to the intermediate hearth and the mold).

  A raw material charging path 9 is provided on one side wall of the raw material melting hearth 2. The raw material 51 is charged into the raw material melting hearth 2 from the raw material charging path 9. Further, a molten metal outlet channel 11 is provided on a side wall portion perpendicular to the one side wall provided with the raw material charging path 9. A molten metal 53 formed by melting the raw material 51 flows from the raw material melting hearth 2 into the intermediate hearth 3 via the molten metal outlet channel 11. The molten metal outlet channel 11 opens upward.

  A plasma torch 5 (plasma heating apparatus) is disposed above the raw material melting hearth 2. The plasma torch 5 is attached to the ceiling wall of the chamber via a bearing (not shown) so as to be slidable in the axial direction (movable up and down) and swingable in any direction of 360 °. (Attached to the chamber in a form that penetrates the chamber). Further, the plasma torch 5 is electrically driven or hydraulically driven, and is moved in accordance with a movement pattern set in advance by a signal from a control device (not shown) (it can be switched manually and moved manually). The same applies to the plasma torch 5 disposed above the intermediate hearth 3 described later, the plasma torch 7 disposed above the mold 4, and the plasma torch (5, 7) shown in FIGS. It is slidable in the axial direction (movable up and down), and can be swung in any direction of 360 °. Or you can move it manually.)

  Here, a thick solid arrow in FIG. 1A moves (oscillates and / or slides) in the plasma injection part 5a (or the center of the plasma gas injected from the plasma injection part 5a) of the plasma torch 5. The range (movement pattern) to be moved (up and down movement) is illustrated. Since the plasma torch 5 disposed above the raw material melting hearth 2 can be moved in this manner, the plasma gas from the plasma torch 5 not only causes the molten metal 53 in the central portion of the raw material melting hearth 2 to move. The raw material 51 of the raw material charging unit 2a (and the hot water surface of the molten metal 53) or the hot water surface of the molten metal 53 of the molten metal outlet channel 11 can be subjected to plasma heating according to the situation.

  If the plasma torch 5 arranged above the intermediate hearth 3 and on the left side in FIG. 1A from the center of the intermediate hearth 3 is arranged on the right side of the center of the intermediate hearth 3, for example, the plasma With the torch 5, the molten metal surface of the molten metal 53 in the molten metal outlet channel 11 can be plasma heated. That is, it is possible to simultaneously plasma-heat the molten metal surface of the raw material charging part 2a and the molten metal outlet channel 11.

(Electromagnetic stirring device)
An electromagnetic stirrer 6 is disposed under the raw material melting hearth 2. More specifically, an electromagnetic stirrer 6 is disposed close to the raw material melting hearth 2 under the raw material melting hearth 2 with a predetermined interval from the bottom surface of the raw material melting hearth 2. The electromagnetic stirring device 6 is a device for stirring the molten metal 53 by generating a horizontal swirling flow in the molten metal 53 in the raw material melting hearth 2. The electromagnetic stirring device 6 may be an EMS (Electro-Magnetic Stirrer) that energizes an alternating current, or may be a mechanical rotary type. Since the dissolution rate of titanium is slow, when the electromagnetic stirring device 6 is not installed, that is, the flow rate in the hearth 2 for dissolving the raw material only by dissolving the titanium raw material is about 1 cm / second at the maximum.

  As shown in FIG. 1 (a), the stirring direction R of the molten metal 53, the stirring direction of the molten metal 53 by the electromagnetic stirring device 6 is the distance of the two stirring directions from the raw material charging unit 2a to the molten metal outlet channel 11. Is preferably the longer stirring direction (clockwise direction in FIG. 1A).

(Intermediate Hearth)
The intermediate hearth 3 is a bottomed holding container that plays a role such as uniformizing the temperature of the molten metal 53, settling and separating inclusions, and reducing a change in the amount of molten metal flowing into the mold 4 due to fluctuations in the molten amount. The intermediate hearth 3 opens upward, and the inner peripheral wall and the outer peripheral wall are both rectangular in plan view. Here, in the present embodiment, the raw material melting hearth 2 is disposed at one end of the long side of the four sides around the intermediate hearth 3, and the mold 4 is disposed at the other end of the long side. That is, the raw material melting hearth 2 and the intermediate hearth 3 are arranged in an L shape, and when the mold 4 is included, the whole is arranged in a U shape.

  Here, at the end of the long side wall of the intermediate hearth 3, a molten metal injection flow path 12 to the mold 4 is provided. The molten metal 53 that has flowed into the intermediate hearth 3 from the raw material melting hearth 2 flows down into the intermediate hearth 3 and then flows into the mold 4 via the molten metal injection channel 12. The molten metal injection channel 12 opens upward. The surface of the molten metal 53 flowing down in the intermediate hearth 3 is plasma heated by the plasma torch 5 disposed above the intermediate hearth 3. Thereby, solidification of the molten metal 53 is prevented. In addition, the range which moves the plasma injection part (or the center of the plasma gas injected from a plasma injection part) of the plasma torch 5 arrange | positioned above the intermediate hearth 3 in FIG. This is illustrated in

(template)
The mold 4 is a bottomless mold for solidifying the poured molten metal 53 into an ingot 55. Since the mold 4 has a rectangular cross section, a slab-shaped (cuboid) ingot 55 is obtained. The drawing device 13 is disposed under the mold 4, and the ingot 55 in which the molten metal 53 is solidified is cast while being drawn downward by the drawing device 13. In addition, the code | symbol 54 in FIG.1 (c) has shown the solidification part. A plasma torch 7 is disposed above the mold 4. The surface of the molten metal 53 flowing into the mold 4 by the plasma torch 7 is heated by plasma.

  Here, the range in which the plasma injection part (or the center of the plasma gas injected from the plasma injection part) of the plasma torch 7 is moved is illustrated by a thick solid arrow in FIG. Since the plasma torch 7 is movable in such a range, both the molten metal surface of the molten metal 53 of the mold 4 and the molten metal surface of the molten metal injection channel 12 can be heated by the plasma gas from the plasma torch 7. It is like that.

  In addition, by extending the moving range of the plasma torch 5 disposed above the intermediate hearth 3 to the molten metal injection channel 12, the molten metal 53 of the molten metal 53 in the molten metal injection channel 12 is caused by the plasma gas from the plasma torch 5. Heating is also possible.

(Action / Effect)
In the present invention, the electromagnetic stirrer 6 is disposed close to the bottom surface of the raw material melting hearth 2, and the electromagnetic stirrer 6 generates a swirling flow in the molten metal 53 in the raw material melting hearth 2 to stir the molten metal 53. Yes. According to this configuration, most of the electromagnetic stirring energy of the electromagnetic stirring device 6 can be used for stirring the molten metal 53 in the raw material melting hearth 2, and the molten metal 53 is sufficiently stirred in the raw material melting hearth 2. (Dissolution efficiency is improved). That is, the contact heat transfer rate from the molten metal 53 to the raw material 51 can be increased by increasing the contact speed between the raw material 51 and the molten metal 53. As a result, it is possible to further prevent operational troubles such as the undissolved raw material 51 flowing into the mold 4 or the undissolved raw material 51 sinking to the bottom of the hearth or adhering to the inner wall of the hearth. When casting the molten metal 53 continuously from Haas to Haas or from Haas to the mold, an electromagnetic stirrer 6 is arranged close to the bottom surface of the material melting hearth 2 located at the most upstream position, for melting the material. It is particularly important that the molten metal 53 in the hearth 2 is swirled to agitate the molten metal 53. Further, since the melting efficiency of the raw material 51 is improved, it is possible to reduce the size of the raw material melting hearth 2 and to improve the power efficiency.

  In the present embodiment, the inner peripheral wall of the raw material melting hearth 2 has a square shape (L1 = L2). The inner peripheral wall of the raw material melting hearth 2 is rectangular (or oval), and the ratio of the length of the long side (or long axis) to the length of the short side (or short axis) of the inner peripheral wall is 1 or more and 1. By setting it to 5 or less, disturbance of the swirling flow in the hearth 2 for dissolving the raw material can be prevented, and the swirling flow velocity can be kept high. As a result, the contact speed between the raw material 51 and the molten metal 53 is further increased. FIG. 4 is a view showing a raw material melting hearth 62 according to a comparative example. As shown in FIG. 4, when the raw material melting hearth 62 has a large aspect ratio, a weak flow region S is generated in the molten metal 53 in the hearth (the swirl flow is disturbed). And the raw material 51 is blown to the area | region S with this weak flow, As a result, the melt | dissolution efficiency of the raw material 51 will fall.

  Further, the stirring direction of the molten metal 53 by the electromagnetic stirring device 6 is set to the stirring direction R having the longer distance of the two stirring directions from the raw material charging unit 2a to the molten metal outlet channel 11, so that the raw material charging unit It is possible to prevent a short-circuit flow from being generated between 2a and the molten metal outlet channel 11, and to effectively prevent the unmelted raw material 51 from coming out of the raw material melting hearth 2.

  Moreover, the molten metal 53 can be stirred also in the intermediate hearth 3 by arranging the intermediate hearth 3 and flowing the molten metal 53 in the intermediate hearth 3. Note that an electromagnetic stirring device 6 may be disposed under the intermediate hearth 3. In this case, the strength of electromagnetic stirring is determined in consideration of the sedimentation efficiency of inclusions.

  Further, the molten metal outlet channel 11 and the molten metal injection channel 12 are portions where the molten metal 53 is easily solidified. By making the surface of the molten metal 53 in the molten metal outlet channel 112 and the molten metal surface of the molten metal injection channel 12 plasma heated, it is possible to effectively prevent the molten metal 53 from solidifying in the flow channel portions. Can do.

(Modification 1)
FIG. 2 is a view showing a modification of the titanium dissolving apparatus 1 shown in FIG. In this embodiment, a rod-shaped titanium alloy is used as the raw material 52 as an example. In addition, the same code | symbol is attached | subjected about the structural member similar to the structural member shown in FIG.

  When a titanium alloy is used as a raw material, the residence time of the molten metal 53 in the hearth needs to be longer than when titanium (pure titanium) is used as a raw material. The ingot (product) of the titanium alloy is required to have a lower inclusion content than the ingot (product) of titanium (pure titanium). Therefore, when using a titanium alloy as a raw material, it is necessary to more reliably remove inclusions from the molten metal 53 by sedimentation separation.

  In the titanium melting apparatus 102 according to the present embodiment, the square heart-shaped two hearths (81, 82) are used, so that the capacity of the hearth is increased and the residence time of the molten metal 53 is lengthened. A flow path 14 is provided between the intermediate hearth 81 and the intermediate hearth 82. The residence time of the molten metal 53 can be increased even if one large intermediate hearth (81, 82) is used, but one large intermediate hearth (81, 82) can be used. It is possible to prevent the occurrence of a short-circuit flow (direct flow) from the raw material melting hearth 2 to the mold 4 as compared with the case of using hearth. Thereby, it is possible to prevent the unmelted raw material 52 from flowing into the mold 10.

  Since the raw material 52 of the titanium alloy is not uniform, the molten metal 53 must be sufficiently stirred in the hearth. From this point of view, the electromagnetic stirring device 6 is disposed close to the bottom surface of the raw material melting hearth 2. Then, it is preferable that the molten metal 53 in the raw material melting hearth 2 is swirled to agitate the molten metal 53.

  In addition, the thick solid arrow in FIG. 2 moves in the plasma injection part (or the center of the plasma gas injected from the plasma injection part) of the plasma torch 5 (or 7) (as in FIG. 1A) ( An example of a range of rocking and / or sliding movement (up and down movement) is illustrated. Also in this embodiment, the molten metal surface of the molten metal 53 of each flow path (11, 12, 14) can be heated by plasma (the same applies to the titanium melting apparatus 103 shown in FIG. 3).

  Since the titanium alloy ingot is mainly a cylindrical product, the mold 10 is a bottomless mold having a circular cross section.

(Modification 2)
FIG. 3 is a view showing a modification of the titanium dissolving apparatus 1 shown in FIG. In addition, the same code | symbol is attached | subjected about the structural member similar to the structural member shown in FIG.

  The difference between the titanium melting apparatus 1 shown in FIG. 1 and the titanium melting apparatus 103 of the present embodiment is the shape of the intermediate hearth and the arrangement of the hearth mold.

  In the present embodiment, the inner peripheral wall and the outer peripheral wall of the intermediate hearth 8 are formed in a square shape in the same manner as the raw material melting hearth 2. Note that the capacity in the intermediate hearth 8 and the capacity in the intermediate hearth 3 shown in FIG. 1 are substantially the same.

  Regarding the arrangement of the hearth and the mold, the raw material charging path 9, the raw material melting hearth 2, the intermediate hearth 8, and the mold 4 are arranged in a line in this order. In addition, the molten metal 53 is poured into the mold 4 from the central portion of the long side wall of the mold 4. In the titanium melting apparatus 1 shown in FIG. 1, the molten metal 53 is injected into the mold 4 from the center of the short side wall of the mold 4.

  Here, the raw material charging path 9, the molten metal outlet flow path 11, and the molten metal injection flow path 12 are shifted from each other so that adjacent ones are not arranged in a straight line. This prevents the occurrence of a short-circuit flow (direct flow) from the raw material melting hearth 2 (and the raw material charging portion 2a) to the mold 4.

  In each of the titanium melting apparatuses (1, 102) shown in FIGS. 1 and 2, the hearth is arranged in an L shape, and when the mold is included, the hearth is arranged in a U shape as a whole. That is, in the titanium melting apparatus (1, 102) shown in FIGS. 1 and 2, by arranging the hearth and the mold in this manner, a short circuit flow (direct flow) from the raw material melting hearth 2 to the mold 4 is generated. Can be prevented.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. .

1: Titanium melting device 2: Raw material melting hearth 3: Intermediate hearth 4: Mold 6: Electromagnetic stirrer 11: Melt outlet channel 12: Molten injection channel 51: Raw material (sponge titanium)
52: Raw material (rod shape)
53: Molten metal

Claims (5)

A titanium melting apparatus that is provided in an apparatus for continuously producing an ingot of titanium or titanium alloy, melts solid titanium or titanium alloy as a raw material by plasma heating to form a molten metal, and flows the molten metal into a mold. There,
Solid titanium or a titanium alloy as a raw material is turned, a hearth for raw material dissolved to the molten metal the material is dissolved by plasma heating,
An electromagnetic stirrer that is disposed in proximity to the bottom surface of the raw material melting hearth and that causes the swirl flow to stir the molten metal in the raw material melting hearth,
Equipped with a,
The raw material melting hearth has a raw material charging part and a molten metal outlet channel,
The distance from the raw material charging part to the molten metal outlet channel differs from each other in two stirring directions from the raw material charging part to the molten metal outlet channel,
The stirring direction of the molten metal by the electromagnetic stirring device, characterized in Rukoto the distance of the two stirring direction is an agitating direction of the longer, titanium dissolution apparatus. The titanium dissolving apparatus according to claim 1, wherein
The inner peripheral wall of the raw material melting hearth is rectangular or oval,
The ratio of the length of the long side or long axis of the inner peripheral wall to the length of the short side or short axis is 1 or more and 1.5 or less. The titanium dissolving apparatus according to claim 1 or 2 ,
A titanium melting apparatus characterized in that not only the molten metal surface in the raw material melting hearth but also the molten metal surface in the molten metal outlet channel can be plasma-heated. In the titanium melt | dissolution apparatus in any one of Claims 1-3 ,
An titanium hearth melting apparatus is provided, wherein an intermediate hearth is provided in which the molten metal flows from the raw material melting hearth and flows into the mold after flowing down. The titanium dissolving apparatus according to claim 4 , wherein
The intermediate hearth has a melt injection channel to the mold,
The titanium melting apparatus, wherein both the molten metal surface in the intermediate hearth and the molten metal surface in the molten metal pouring channel can be heated by plasma.

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