JP6183598B2 - Magnet alloy production equipment - Google Patents

Description

  The present invention relates to an alloy manufacturing apparatus for manufacturing a magnet alloy, and more particularly to an alloy manufacturing apparatus suitable for manufacturing a magnet alloy containing an alloy component that easily evaporates.

  Rare earth magnets containing rare earth elements such as Nd and Sm are known as high performance magnets having excellent residual magnetic flux density and holding power compared to conventional ferrite magnets. As a method for producing such a rare earth magnet, for example, there is a method in which a rapidly solidified piece is subjected to pressure sintering and bulked. More specifically, a magnet alloy having a predetermined component composition containing a rare earth element is melted, and the molten metal is sprayed onto a water-cooled rotating roll to obtain a rapidly solidified piece. When this is pulverized and then sintered under pressure, it becomes a bulky rare earth magnet. By pressure-sintering a rapidly solidified piece, not just a solidified piece of alloy, the metal structure of the magnet can be refined to improve the magnetic properties.

  For example, Patent Document 1 discloses a manufacturing apparatus for obtaining a rapidly solidified piece for a rare earth magnet by a single roll method including a tundish. An induction heating melting furnace for melting a rare earth magnet alloy containing a rare earth element in a sealed space of a vacuum or an inert gas atmosphere, and a tundish for receiving molten metal and pouring it onto the surface of a cooling roll on the downstream side And a cooling roll for rapidly cooling the molten metal that rotates forward at a high speed and is poured onto the molten metal. The induction heating furnace is rotatably supported, and when it is rotated and the molten metal is sent to the tundish, the molten metal is poured onto the cooling roll. A scraper is provided in contact with the downstream surface of the cooling roll, and the rapidly solidified piece is separated from the cooling roll and collected.

  Patent Document 2 discloses an apparatus for producing rapidly solidified pieces for a rare earth magnet by a single roll method provided with a square cylindrical rounder for receiving molten metal from a melting furnace and flowing it to a tundish. The melting furnace and the tundish are provided in separate chambers of the melting chamber and the casting chamber, respectively, and a gate valve is provided between them. The rounder on the casting chamber side opens the gate valve, moves to the melting chamber side, and receives the molten metal from the melting furnace at its end. The molten metal flows along an inclined rounder at the bottom and flows into the tundish from the opposite end. Thereafter, the rounder moves again to the casting chamber side, and the gate valve is closed. By dividing the melting chamber and the casting chamber with an openable / closable gate valve, the melting furnace can be repaired without being affected by the operating state in the casting chamber.

  By the way, in order to obtain a stronger rare earth magnet, it is required to obtain a solidified piece that melts while accurately controlling the component composition of the magnet alloy and maintains the component composition without involving impurities.

  For example, in Patent Document 3, in a rapidly solidified piece manufacturing apparatus for a rare earth magnet by a single roll method, Sm having a good magnetic property by adjusting a rare gas atmosphere pressure in a room where a cooling roll is arranged and a discharge pressure of a nozzle. It discloses that a -Fe-N magnet can be manufactured stably. Sm is higher in vapor pressure than Nd used in Nd-Fe-B rare earth magnets, and is likely to evaporate before the alloy melt solidifies, evaporates until it is discharged from the nozzle and reaches the surface of the cooling roll, It also states that it evaporates from the paddle, and that the compositional variation of the quenched alloy produced therefor occurs.

JP 2000-79449 A JP 2004-154788 A JP 2000-1204017 A

  In the rare earth magnet manufacturing apparatus, by increasing the amount of the magnet alloy melted in one batch, the production efficiency can be increased and the manufacturing cost can be suppressed. On the other hand, a large melting furnace is required, which enlarges the apparatus. Therefore, there is a demand for a small manufacturing apparatus with high production efficiency.

  Here, in order to stably manufacture a high-performance rare earth magnet, it is required that the component composition of the magnet alloy can be accurately controlled. In particular, since an element having a high vapor pressure such as Sm is likely to evaporate, it is difficult to accurately control the component composition of the magnet alloy.

  The present invention has been made in view of the situation as described above, and the object of the present invention is to accurately control the composition of a magnet alloy including an alloy component that easily evaporates. The object is to provide a small magnet alloy manufacturing apparatus with high production efficiency.

  An alloy manufacturing apparatus for manufacturing a magnet alloy according to the present invention includes a first melting furnace for melting and storing a base metal, a second melting furnace for preparing the magnet alloy, and the first And a transfer means for transferring a part of the molten metal taken out from the melting furnace to the second melting furnace, and an addition device for introducing the retained additive metal to the second melting furnace. To do.

  According to this invention, since the alloy prepared for supplying to a tundish or the like is not stored for a long time, the composition of the component can be accurately controlled even for an alloy for a magnet containing an alloy component that easily evaporates. is there. In addition, the alloy for magnets can be prepared by the second melting furnace which is not a batch type but a continuous type, and high production efficiency is provided while being a small apparatus.

  In the above-described invention, the transfer means is a bowl-shaped container that moves from outside the path for guiding the additive metal, and has one end disposed in the vicinity of the first melting furnace and the other end. Is disposed immediately above the second melting furnace, and a part of the molten metal taken out from the first melting furnace moves over the second melting furnace and flows into the second melting furnace. Also good. According to this invention, the size of the entire alloy manufacturing apparatus can be made compact while ensuring the size of the first melting furnace for melting and storing the base metal.

  In the above-described invention, the first melting furnace and the second melting furnace are disposed inside the independent first chamber and second chamber, respectively, and can be opened and closed between the first chamber and the second chamber. A shutter may be provided, and the transfer means may be movable so as to be disposed in the vicinity of the melting furnace through the inside of the shutter whose one end is opened. According to this invention, the magnet alloy can be sequentially prepared without changing the atmosphere of the second melting furnace, and a large amount of the magnet alloy can be manufactured stably, so that the cost can be greatly reduced.

It is a block diagram of the alloy manufacturing apparatus by this invention. It is a figure which shows the time table in a 1st melting furnace, a 2nd melting furnace, and a tundish. It is a block diagram in 1 process of the alloy manufacturing apparatus by this invention. It is a block diagram in 1 process of the alloy manufacturing apparatus by this invention. It is a block diagram in 1 process of the alloy manufacturing apparatus by this invention. It is a block diagram in 1 process of the alloy manufacturing apparatus by this invention. It is a block diagram in 1 process of the alloy manufacturing apparatus by this invention. It is a block diagram of the other alloy manufacturing apparatus by this invention. It is a figure which shows the time table in a 1st melting furnace, a 2nd melting furnace, and a tundish.

  An apparatus for producing a rare earth magnet alloy according to one embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the magnet alloy manufacturing apparatus 10 includes a first chamber 11 and a second chamber 12 whose internal space can be controlled to a vacuum or an inert gas atmosphere and its pressure can be controlled. The first chamber 11 has a freely openable / closable shutter 15 as a gate valve on the side, and is connected to the second chamber 12 through the side. The first chamber 11 houses therein a first melting furnace 1 that is an induction heating furnace capable of melting metal by induction heating.

  The second chamber 12 accommodates therein the second melting furnace 2, the dredge 4, the tundish 5, the cooling roll 6, and the slab collecting device 7, and the addition device 3 via a gate valve 16 on the outside upper side thereof. Is connected. The second melting furnace 2 is an induction heating furnace that melts metal by induction heating as in the first melting furnace, but is a small furnace having a smaller melting capacity than the first melting furnace 1. The second melting furnace 2 transfers, receives and holds a part of the molten metal from the first melting furnace 1, but since it is a small furnace, the entire amount is discharged without storing the adjusted molten alloy for magnets for a long time. Can do. Details will be described later.

  The adding device 3 includes a bucket 31 attached so as to be movable up and down. When the bucket 31 is lowered and inserted into the second chamber 12 from the lower gate valve 16, the added metal held in the bucket 31 is dropped. The second melting furnace 2 can be charged. By introducing the additive metal to the second melting furnace 2 with the addition device 3, the components of the magnet alloy can be adjusted in the second melting furnace. In addition, the inside of the addition apparatus 3 is controlled to the same atmosphere as the inside of the second chamber 12, so that the atmosphere of the second melting furnace 2 can be prevented from changing when the gate valve 16 is opened.

  The gutter 4 guides the molten metal received at the injection side end 41 which is one end thereof to the discharge side end 42 which is the other end, and from the discharge port 43 provided at the bottom of the discharge side end 42. It is a bowl-shaped container that is discharged downward. That is, the gutter 4 has a bottom portion that is inclined downward from the injection side end portion 41 toward the discharge side end portion 42.

  The trough 4 can be moved horizontally from an initial position by an actuator (not shown), and serves as a transfer means for transferring the molten metal taken out from the first melting furnace 1 to the second melting furnace. That is, the cage 4 is normally disposed at an initial position where it does not interfere with a path for introducing the added metal from the adding device 3 including the descending path of the bucket 31, that is, a falling path of the added metal. On the other hand, the shutter 15 is opened and an actuator (not shown) is operated to move the rod 4. The injection side end 41 of the tub 4 passes through the opened shutter 15 and enters the first chamber 11 and is located near the first melting furnace 1 and stops at this transfer position (FIG. 6). reference). At this time, the discharge port 43 of the discharge side end portion 42 of the trough 4 is positioned directly above the second melting furnace 2. At the transfer position, the molten metal discharged from the first melting furnace 1 can be poured into the injection side end 41 of the trough 4, discharged from the discharge port 43, and poured into the second melting furnace 2. In this way, the basket 4 is movable between the initial position and the transfer position, and the entire arrangement is made compact without interfering with the operation of the addition device 3.

  The tundish 5 is a crucible made of refractory, and can heat the molten metal stored inside by resistance heating. Further, the tundish 5 is arranged so as to receive the molten metal discharged from the second melting furnace 2, and can store the molten metal even if the entire amount of the molten metal is discharged from the second melting furnace 2, at least the second melting furnace. The capacity is equivalent to 2. The tundish 5 can rectify the stored molten metal and pour the molten metal from the bottom outlet 51 to the surface of the cooling roll 6.

  The cooling roll 6 is a water-cooled rotary roll having a cooling surface made of a metal having a high thermal conductivity such as a copper alloy, and its rotation is controlled by a driving device (not shown). By pouring the molten metal onto the surface of the rotated cooling roll 6, the molten metal is rapidly solidified while being guided in the rotation direction, and a strip-shaped metal flake having a predetermined thickness can be obtained.

  The cast piece collection device 7 is a device for collecting the thin piece obtained by the cooling roll 6 and includes a scraper 71, a collision plate 72, and a collection container 73. The scraper 71 is disposed so that the blade-like tip end portion is close to the surface of the cooling roll 6, and the rapidly cooled strip-like thin piece is peeled off from the cooling roll 6. The collision plate 72 is a plate-like body for dropping the flakes peeled off by the scraper 71 into the collection container 73 while being crushed. The collision plate 72 is attached to the scraper 71 with the main surface that collides the flakes arranged substantially vertically. Yes. The collection container 73 is a basin-shaped container for collecting the flakes peeled off from the cooling roll 6, and is disposed below the collision plate 72.

  By the way, the magnet alloy manufacturing apparatus 10 described above is suitable for manufacturing a rare earth magnet alloy, particularly a rare earth magnet alloy containing a metal element having a high vapor pressure such as Sm. Here, the metal having a high vapor pressure evaporates and fluctuates the component composition of the alloy if the storage time as the molten metal before being subjected to the solidification step after the alloy melting step is long. Therefore, it is necessary to readjust the component composition, such as additionally adding a metal having a high vapor pressure, thereby reducing the production efficiency. On the other hand, if the amount of molten metal in the alloy melting step is reduced and the storage time until the solidification step is shortened so as to prevent fluctuations in the component composition, the production amount of the magnet alloy per batch decreases. Therefore, the alloy melting process is repeated, which also reduces the production efficiency.

  On the other hand, according to the magnet alloy manufacturing apparatus 10, the master alloy (base material) molten metal is transferred from the large first melting furnace 1 to the small second melting furnace 2 through the rod 4, and then the addition apparatus. When the component composition is prepared by adding a metal having a high vapor pressure according to No. 3, it can be immediately supplied to the cooling roll 6 which is a solidification apparatus. That is, an alloy flake can be obtained without shortening the storage time in the second melting furnace 2 of an alloy containing a metal having a high vapor pressure and without changing the component composition of the magnet alloy. Moreover, although the supply amount of the magnet alloy per batch from the small second melting furnace 2 is small, the alloy flakes can be obtained with high production efficiency by sequentially transferring the mother alloy molten metal through the trough 4. Furthermore, the size of the second melting furnace 2 can be reduced, and the size of the magnet alloy manufacturing apparatus 10 as a whole can be made compact by making the rod 4 movable. Further details will be described later.

  Subsequently, the operation of the magnet alloy manufacturing apparatus 10 will be described along with FIG. 2 and FIG. 3 to FIG. 7 together with an example of manufacturing an alloy for an Sm—Fe—Zr—Co based magnet. To do.

  Here, the Sm—Fe—Zr—Co based magnet is manufactured by an alloy in which Fe is provided with Sm, Zr, and Co. Among these, as described above, Sm is an element having a high vapor pressure, and Zr is an element that easily changes to an oxide by reacting with a furnace wall of a melting furnace at a high temperature. That is, even if the molten alloy for magnets is adjusted to a predetermined component composition, the components of Sm and Zr change when stored for a long time. Therefore, the capacity of the second melting furnace 2 is reduced so that the molten metal containing Sm and Zr is not stored in the second melting furnace 2 for a long time, and Sm and Zr are added in accordance with the hot water discharged from the second melting furnace 2. .

  Referring to FIG. 3 together with FIG. 2, first melting is first performed in the first melting furnace 1 and the second melting furnace 2 (S1). Specifically, a predetermined amount of Fe and Co is dissolved in each melting furnace. Vacuum refining is performed as necessary. Here, the molten metal is a mother alloy (base material) molten metal before component adjustment as an alloy for magnets, and does not contain Sm and Zr as described above. On the other hand, during the initial melting, a predetermined amount of Sm and Zr to be added to the second melting furnace 2 is held in the bucket 31 in the adding device 3 as the added metal 39.

  Subsequently, referring to FIG. 4, additional melting of Sm and Zr is performed in the second melting furnace 2 (S2). Specifically, first, the inside of the second chamber 12 and the inside of the adding device 3 are filled with an inert gas atmosphere, and the pressure is controlled. Next, the gate valve 16 is opened, the bucket 31 is lowered, the added metal 39 is dropped from the upper part of the second melting furnace 2, and Sm and Zr are added to the molten master alloy. When the addition is completed, the bucket 31 is raised and returned to the original position, and the gate valve 16 is closed. As a result, a molten metal whose components are adjusted as a magnet alloy is obtained in the second melting furnace 2.

  Next, referring to FIG. 5, the second melting furnace 2 is tilted to discharge the entire amount of molten metal in the tundish 5 (S 3). As described above, since the second melting furnace 2 is a small-sized furnace, the entire amount of the molten metal whose components are adjusted as a magnet alloy can be discharged to the tundish 5 without storing it for a long time. The tundish 5 that has received hot water starts pouring from the hot water outlet 51 to the surface of the cooling roll 6. The cooling roll 6 is rotated in advance, and the received molten metal is rapidly cooled while extending in the rotation direction, thereby forming a strip-shaped flake. The flakes reach the tip of the scraper 71 by the rotation of the cooling roll 6 and are peeled off from the surface of the cooling roll 6, fly by the inertial force, and collide with the collision plate 72. The flakes that collide with the collision plate 72 fall into the collection container 73 while being crushed by the impact. That is, a rapidly cooled flake for a rare earth magnet having a predetermined composition can be obtained by strip casting. The second melting furnace 2 having finished pouring is returned to its original inclination.

  Subsequently, referring to FIG. 6, the molten mother alloy is received in the second melting furnace 2 (S <b> 4). Specifically, the pressure inside the first chamber 11 is controlled to an inert gas atmosphere in the same manner as the inside of the second chamber 12, and then the shutter 15 is opened. Thereby, the atmosphere inside the second chamber 12 does not change. The rod 4 moves from its initial position to the transfer position through the inside of the shutter 15 with the injection end 41 opened. Here, the first melting furnace 1 is tilted to discharge a part of the mother alloy melt. Such molten metal is poured into the injection end 41 of the tub 4, guided to the discharge side end 42 side by the inclination of the bottom of the tub 4, and poured into the second melting furnace 2 from the discharge port 43. When a predetermined amount of molten metal is transferred to the second melting furnace 2, the inclination of the first melting furnace is returned to the original position, the rod 4 is returned to the initial position, and the shutter 15 is closed. In addition, after the first additional melting (S2), a predetermined amount of Sm and Zr to be added next time is held as the added metal 39 in the bucket 31 of the adding device 3 so far.

  Subsequently, referring to FIG. 7, the additive metal is additionally melted in the second melting furnace 2 in the same manner as S2 described above (S5). That is, the additive metal 39 is dropped onto the mother alloy melt of the second melting furnace 2 by the addition device 3 and Sm and Zr are added. By such additional melting, in the second melting furnace 2, a molten metal whose components are adjusted as a magnet alloy can be obtained again. In addition, the tundish 5 is continuing the pouring to the cooling roll 6, storing a molten metal from the first receiving hot water to here.

  Referring to FIG. 5 again, the second melting furnace 2 is tilted to discharge the entire amount of the molten metal and pour it into the tundish 5 (S6). At this time, the tundish 5 can receive the newly adjusted alloy while continuing the pouring of the cooling roll 6, and can continuously pour the alloy from the hot water outlet 51 to the surface of the cooling roll 6.

  Thereafter, in the second melting furnace 2, the receiving of the molten mother alloy (S7), the additional melting of the added metal (S8), and the total amount of molten metal (S9) are repeated in the same manner. Such repetition is possible until the molten master alloy held in the first melting furnace 1 runs out. That is, the small second melting furnace 2 can be used as a continuous melting furnace, and rapidly cooled flakes for rare earth magnets having a predetermined component composition can be obtained continuously.

  As described above, according to the present embodiment, a part of the mother alloy molten metal is transferred from the first melting furnace 1 to the second melting furnace 2, and the components of the magnet alloy are adjusted in the second melting furnace 2. Give this to Dish 5. Thereby, the molten metal whose components are adjusted is not stored for a long time. Therefore, even if it is a molten metal containing elements such as Sm that easily evaporates and highly reactive Zr, the component composition can be accurately controlled. In addition to Sm, elements that easily change the components in the molten metal over time, such as Mn, Zn, Mg, Ca, Li, and the like, can be used in the production of an alloy that is added in the same manner.

  Further, by means of the rod 4 moving from the initial position to the transfer position, the means for transferring the molten mother alloy can be made compact, and the overall size of the magnet alloy manufacturing apparatus 10 can be increased while ensuring the size of the first melting furnace 1. Can be made compact. On the other hand, as described above, a part of the molten mother alloy is sequentially transferred from the first melting furnace 1 to the small second melting furnace 2 and used as a continuous melting furnace, so that high production efficiency is achieved despite being compact. can get.

  Further, since the first melting furnace 1 is provided in the first chamber 11 provided as a separate chamber from the second chamber 12 and the shutter 15 is provided between them, the shutter without changing the atmosphere of the second melting furnace 2 is provided. 15 can be opened and closed to sequentially adjust the magnet alloy. In other words, a magnet alloy having a stable component composition can be continuously produced, and the production cost can be greatly reduced.

  Further, as shown in FIG. 8, an addition device 3 ′ can be provided in the first chamber 11 so that the metal (Fe, Co) serving as a mother alloy can be additionally mounted on the first melting furnace 1. In this case, as shown in FIG. 9, after partial hot water (S 4, S 7) from the first melting furnace 1 (S 5, S 8), additional melting of the metal that becomes the mother alloy can be performed. That is, it is possible to stably produce a larger amount of magnet alloy and further improve the production efficiency.

  In the present embodiment, the magnet alloy flakes are manufactured by the strip casting method. However, the magnet metal flakes can be obtained by various solidification devices such as an apparatus for manufacturing a continuous ribbon by the melt spinning method.

  As mentioned above, although the Example by this invention and the modification based on this were demonstrated, this invention is not necessarily limited to this, A person skilled in the art will deviate from the main point of this invention, or the attached claim. Various alternative embodiments and modifications could be found without doing so. For example, a fixed ridge 4 may be employed.

DESCRIPTION OF SYMBOLS 1 1st melting furnace 2 2nd melting furnace 3 Addition device 4 樋 5 Tundish 6 Cooling roll 7 Slab collection device 10 Magnet alloy production device

Claims (3)

An alloy manufacturing apparatus for manufacturing a magnet alloy,
A first melting furnace for melting and storing the base metal;
A second melting furnace for preparing the magnet alloy;
Transfer means for transferring a part of the molten metal taken out from the first melting furnace to the second melting furnace;
And an addition apparatus for introducing the retained additive metal to the second melting furnace.   The transfer means is a bowl-shaped container, and moves from outside the path for guiding the additive metal, and has one end disposed in the vicinity of the first melting furnace and the other end is the second 2. The apparatus according to claim 1, wherein the molten metal is disposed immediately above the melting furnace, and a part of the molten metal taken out from the first melting furnace moves over the molten metal and flows into the second melting furnace. Alloy manufacturing equipment. The first melting furnace and the second melting furnace are respectively disposed in independent first chamber and second chamber, and a shutter is provided between the first chamber and the second chamber so as to be freely opened and closed. 3. The alloy manufacturing apparatus according to claim 2, wherein the transfer means is movable so as to pass through the inside of the shutter having the one end opened and to be disposed in the vicinity of the first melting furnace.

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