JPH01248503A - Manufacture of r-fe-b family anisotropy magnet - Google Patents
Manufacture of r-fe-b family anisotropy magnetInfo
- Publication number
- JPH01248503A JPH01248503A JP63075614A JP7561488A JPH01248503A JP H01248503 A JPH01248503 A JP H01248503A JP 63075614 A JP63075614 A JP 63075614A JP 7561488 A JP7561488 A JP 7561488A JP H01248503 A JPH01248503 A JP H01248503A
- Authority
- JP
- Japan
- Prior art keywords
- magnet
- extrusion
- alloy powder
- manufacturing
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 20
- 239000000843 powder Substances 0.000 claims abstract description 23
- 239000000463 material Substances 0.000 claims abstract description 21
- 238000001125 extrusion Methods 0.000 claims abstract description 18
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 10
- 239000000956 alloy Substances 0.000 claims abstract description 10
- 238000001192 hot extrusion Methods 0.000 claims abstract description 10
- 238000005520 cutting process Methods 0.000 claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 238000007789 sealing Methods 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 12
- 229910001004 magnetic alloy Inorganic materials 0.000 claims description 10
- 239000013078 crystal Substances 0.000 claims description 4
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 235000012438 extruded product Nutrition 0.000 claims description 3
- 238000007731 hot pressing Methods 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 238000012856 packing Methods 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims 1
- 230000005415 magnetization Effects 0.000 abstract description 7
- 238000003466 welding Methods 0.000 abstract description 5
- 239000000203 mixture Substances 0.000 abstract description 2
- 230000001939 inductive effect Effects 0.000 abstract 1
- 230000003068 static effect Effects 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract 1
- 238000005336 cracking Methods 0.000 description 5
- 238000010791 quenching Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 230000002706 hydrostatic effect Effects 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001020 Au alloy Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000003353 gold alloy Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000000886 hydrostatic extrusion Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910001172 neodymium magnet Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000009931 pascalization Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0576—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together pressed, e.g. hot working
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
［産業上の利用分野］
本発明は、Ｒ−Ｆｅ −Ｂ系永久磁石であって、異方性
をもったものの製造方法の改良に関する。
［従来の技術］
Ｎｄ −Ｆｅ −Ｂ系に代表されるＲ−Ｆｅ −Ｂ系［
Ｒはｌａ系希土類元素］永久磁石は、すぐれた磁気特性
を買われて、広い分野で採用が試みられている。 とく
に高い磁気特性は、Ｒ−Ｆｅ−Ｂ系磁石合金の溶場を超
急冷装置により急冷薄帯にし、それを粉砕した材料を使
用することによって得られる。 磁石粉末を不活性雰囲
気中、温度的７００℃でホットプレスにより成形し、磁
化させると等方性磁石となる。 ホットプレス後、さら
に不活性雰囲気中、やはり約７００℃で圧下率５０％以
上の塑性変形を行なうと、磁化容易軸（Ｃ軸）が変形時
の流れ方向と直交する加工集合組織が得られ、これを磁
化すれば、最大エネルギー積（Ｂ Ｈ） ｍａｘが極め
て大きな異方性磁石が１ｑられる。
ところが、この異方性１石を商業規模で生産するに当っ
て、つぎのような問題があり、それがＲ−Ｆｅ−Ｂ系磁
石のコスト低下を妨げる大きな原因になっている。
第一の問題は、この材料がきわめて酸化されやすく、大
気中で加熱したのでは瞬時に酸化が進んで、所望の磁気
特性が得られなくなることである。
このため従来は、成形用の金型を真空槽内に収容して’
ＩＱ−３Ｔｏｒｒ程度に真空吸引した状態か、または真
空吸引に続いてＡｒのような不活性ガスを封入した状態
で、加熱、成形するという手段をとらざるを得なかった
。 このような製法では成形サイクルが３０分以上に延
び、生産性が低い。
第二の問題は、この材料が室温ではきわめて硬く脆いた
め、加工は５００〜８００℃の狭い温度範囲内で熱間で
行なうしかなく、それでも加工ワレが発生しやすいとい
うことである。 この高性能磁石の用途は、ブラシレス
モータ、サーボモータ、ボイスコイルモータなどが中心
であって、薄肉のリングやアークセグメントの形をとる
か、あるいは異型品にしても、肉厚が薄く寸法精度の高
い部品が要求される。 上記の熱間加工としてプレス圧
縮または熱間押出しを採用し、これを１回行なっても所
望の薄肉品を得ることはできず、２回以上の加工が必要
であって、そのつど、酸化防止策をとらねばならない。
機械加工により薄肉を１ｑることも考えられるが、上
記のように硬く脆い材料であるから、切削は実際上不可
能に近い。
［発明が解決しようとする課題］
本発明の目的は、Ｒ−Ｆｅ−Ｂ系磁石の加工に関して従
来技術がかかえていた問題に取り組み、大気中での１回
の塑性変形により、ワレを防いで薄肉の成形品を得るこ
とのできる希土類磁石の製造方法を提供することにある
。
［課題を解決するための手段］
本発明のＲ−Ｆｅ −Ｂ系異方性磁石の製造方法は、下
記の諸工程からなる。
イ）Ｒ−Ｆｅ −Ｂ＠磁石合金の粉末を缶内に充填し、
真空吸引下に気密に密封する工程、口）磁石合金の粉末
を封入した缶を加熱し、熱間押出しプレスにより押出し
成形し、それによって結晶異方性を付与する工程、およ
び
ハ）押出し成形体から所定の形状の磁石材料を切り出し
、缶材料を除去して磁化する工程。
上記の系において、ＲはＮｄで代表されるＬａ系希土類
元素である。 この磁石は、少量のｃｏ。
Ｄ’／２０３などの磁石性能を向上させるための物質や
、Ｎｉ 、Ｚｎ、Ｐｂ、Ａｌなどの耐食性、耐熱性、加
工性を改善するための物質を含んでいてもよい。
上記の工程イ）においては、できるだけ高密度の充填を
することが望ましい。 それには、っぎのような手法が
ある。 最も簡単なものは振動充填法であって、缶に振
動を加えつつ粉末を装入することにより、理論密度比に
して約５５％の充填ができる。
いまひとつは、缶に装入した粉末を冷間プレスすること
であって、３〜７トン／ＣＵｔの圧力をかけることによ
り、理論密度比的８０％の充填が行なえる。
最高の充填密度を１ｑるには、ｔａ−５合金の粉末を缶
に入れ、１０−３Ｔｏｒｒより低圧の真空下または不活
性ガス雰囲気下に５００〜８００℃に加熱してホットプ
レスするとよい。 これにより、理論密度比的９５％に
到達する。 ホットプレスに先立って、ｌａ石金合金粉
末を冷間で圧粉成形しておくのもよい。
工程口）における熱間押出しプレスとしては、熱間静水
圧押出しが好適である。
工程口）において、押出し成形品の肉厚ｔと幅Ｗとの間
にｔ≦ｗ／３の関係が１９られる条件で熱間押出し加工
を行なえば、肉厚方向に異方性をもつ薄肉平板状の磁石
が製造できる。
［作 用］
以下、図面を参照しつつ、上記の製造方法を説明する。
Ｒ−Ｆｅ−Ｂ系磁石合金の粉末は、前記したように、超
急冷により製造した急冷薄帯の粉末が好適である。 第
１図に示すように、この粉末１を、缶２の中に充填する
。 缶２は中空の円筒を与える形状をもっているが、中
実の円柱状のものをつくるのであれば、それに応じた形
状の缶を用意すればよいことはいうまでもない。 缶は
、軟鋼や純銅のような、熱間塑性加工が容易な材料で製
作し、合わせ目を溶接かロウ付けで気密にして用いる。
上記いずれかの手段で磁石合金粉末を充填した缶は、
蓋をしてやはり溶接などの方法で蓋をとりつける。 振
動充填の場合は、蓋をつけておいて充填することも可能
である。
このようにして用意した充填体を、続いて真空槽内に置
いて脱気したのち、開口部２１を電子ビーム溶接などで
溶接密封して缶封体とする。 このときの真空度は、１
ｏ−３ｒｏｒｒまたはそれより強い減圧とすることが望
ましい。
缶封体は、輻射または高周波誘導加熱により、加工温度
まで昇温させる。 これは、もちろん大気中で行なって
よい。 温度は、変形能からみて５００℃以上とする必
要があり、それより低いと加工ワレを生じやすい。 ま
た、８００℃を超える温度は、結晶粒の成長が著しくな
って磁気特性をそこなう。 これらを総合すると、７０
０〜７５０℃の範囲が最適である。
加熱した缶封体は、熱間押出しにより所定の寸法のパイ
プに加工する。 中空体でなければ、棒状に加工する。
押出し加工を行なうのは、この材料が熱間でもなお変
形能が低く加工ワレが生じやすいからであって、ワレを
防ぐには、圧縮応力の加わる成形手段をとることが望ま
しい。
ワレの防止にとくに効果的なのは、熱間静水圧押出しで
ある。 第２図は、上記のようにして得た中空の缶封体
に対して、それを行なっているところを示す。 加熱し
た缶封体３をコンテナー５内に収容し、ステム６で（図
では左方から矢印方向に）押すことによって、ダイ８Ａ
とマンドレル８Ｂの間でこれが成形され、パイプ９とな
って（図では右方に）押し出される。
コンテナー５内には、加工温度で粘性をもち非圧縮性の
媒体７、たとえば耐熱グリースを封入して型の合わせ目
をシールしておけば、ステム６の移動によりコンテナー
内部の空間容積が縮小して、媒体内に高い静水圧が発生
する。 この静水圧は、缶封体３の全表面に対して圧縮
応力として作用し、その変形に伴うワレを防ぐことがで
きる。 この場合の静水圧の高さは３，０００〜１０，
０００Ｋｇ／ｃｒｉが適当で、これより低圧ではワレ発
生防止に効果が乏しく、これより高圧では型の強度が耐
えないであろう。
このほか、静水圧押出しには、媒体がグイと加工材、マ
ンドレルと加工材の間に薄膜として存在してそれらの直
接接触を防ぐ潤滑剤としてはたらき、摩擦係数を小さく
するという効果がある。
従って、熱間静水圧押出しは薄肉小径のパイプ状製品を
１ｑる場合に、とくに有利である。 従来のガラス潤滑
押出しでは、この摩擦仕事が大きくなるため、得られる
パイプは最小直径２５１Ｎｒ１、最小肉厚３Ｍが限界で
あった。 Ｒ−Ｆｅ−Ｂ系磁石の利点を生かすには、最
小直径１５ｍ、最小肉厚１１ＩＩ！ｒ１のパイプが欲し
いところ、従来の手法ではさらに熱間圧延などの工程を
追加しなければならなかったが、熱間静水圧押出しなら
ば、このような小径薄肉のパイプを１工程で成形できる
。
前記したように、磁化容易軸は塑性変形時の流れ方向に
直交する方向となるから、この押出し成形によって、パ
イプの半径方向の異方性をもった組織ができる。 得ら
れたペイプ９を所定の長さに切断し、内外に残っている
缶材料を除去し、続いて磁化することによって、半径方
向の磁極をもった異方性磁石ができる。 缶材料の除去
は、切断に先立って行なってもよいし、場合によっては
磁化の後にすることもできるが、上記のように切断と磁
化の間に実施するのが好都合である。
以上は、最も謂要の多いリング状の異方性磁石を製造す
る場合であるが、本発明の異方性磁石の。
製造方法は、円弧状断面のアークセグメントや、平板状
の異方性磁石の製造にも利用できる。 円弧状のものは
リングの切断によっても（ｑられるから、平板状のもの
のｍ造についていえば、直方体形状の缶を用いた缶封体
を用意し、その押出し成形時に厚さ方向の圧下率が大き
く幅方向の圧下率が小さくなるようなダイス形状をえら
ぶことによって、厚さ方向に大部分の磁化容易軸をそろ
えればよい。 これは、第３図におけるＡ−＋８の変化
に示すように、厚さｔが幅Ｗの１／３以下であるような
寸法をえらぶことにより実現する。[Industrial Field of Application] The present invention relates to an improvement in the manufacturing method of an R-Fe-B permanent magnet having anisotropy. [Prior art] R-Fe-B system represented by Nd-Fe-B system [
[R] is a rare earth element of the la system] Permanent magnets are recognized for their excellent magnetic properties and are being used in a wide range of fields. Particularly high magnetic properties can be obtained by using a material obtained by quenching the melt field of an R-Fe-B magnetic alloy into a thin ribbon using an ultra-quench cooling device and pulverizing the thin ribbon. When the magnet powder is hot pressed in an inert atmosphere at a temperature of 700° C. and magnetized, it becomes an isotropic magnet. After hot pressing, plastic deformation is further performed in an inert atmosphere at approximately 700°C with a reduction rate of 50% or more, resulting in a processed texture in which the axis of easy magnetization (C axis) is perpendicular to the flow direction during deformation. If this is magnetized, 1q of anisotropic magnets with an extremely large maximum energy product (B H) max can be obtained. However, in producing this anisotropic monolith on a commercial scale, there are the following problems, which are a major cause of hindering the cost reduction of R-Fe-B magnets. The first problem is that this material is extremely susceptible to oxidation, and when heated in the atmosphere, oxidation progresses instantaneously, making it impossible to obtain the desired magnetic properties. For this reason, conventionally, the mold for molding was housed in a vacuum chamber.
It was necessary to heat and mold the material under vacuum suction to about IQ-3 Torr, or under vacuum suction followed by filling in an inert gas such as Ar. In such a manufacturing method, the molding cycle is extended to 30 minutes or more, resulting in low productivity. The second problem is that this material is extremely hard and brittle at room temperature, so processing must be carried out hot within a narrow temperature range of 500 to 800°C, and even then processing cracks are likely to occur. These high-performance magnets are mainly used in brushless motors, servo motors, voice coil motors, etc., and can be used in the form of thin-walled rings or arc segments, or even in irregularly shaped products. Expensive parts are required. Press compression or hot extrusion is adopted as the above hot processing, but even if this is performed once, it is not possible to obtain the desired thin-walled product, and the processing is required two or more times. We must take measures. It is possible to reduce the thickness by 1q by machining, but since the material is hard and brittle as described above, cutting is practically impossible. [Problems to be Solved by the Invention] The purpose of the present invention is to address the problems faced by the prior art regarding the processing of R-Fe-B magnets, and to prevent cracking by one-time plastic deformation in the atmosphere. It is an object of the present invention to provide a method for producing rare earth magnets that can produce thin-walled molded products. [Means for Solving the Problems] The method for manufacturing an R-Fe-B anisotropic magnet of the present invention includes the following steps. b) Fill a can with R-Fe-B@magnetic alloy powder,
A process of airtightly sealing the magnetic alloy powder under vacuum suction; (1) a process of heating a can filled with magnetic alloy powder and extruding it using a hot extrusion press, thereby imparting crystal anisotropy; and (3) a process of imparting crystal anisotropy to the extruded product. The process of cutting out magnet material in a predetermined shape from the can material, removing the can material, and magnetizing it. In the above system, R is a La-based rare earth element represented by Nd. This magnet has a small amount of co. It may contain a substance for improving magnet performance, such as D'/203, and a substance for improving corrosion resistance, heat resistance, and processability, such as Ni, Zn, Pb, and Al. In the above step (a), it is desirable to pack as densely as possible. There is a method like this. The simplest method is the vibratory filling method, in which the can is charged with powder while being vibrated, and can be filled to approximately 55% of the theoretical density ratio. Another method is to cold press the powder charged into the can, and by applying a pressure of 3 to 7 tons/CUt, it is possible to achieve a filling of 80% of the theoretical density. In order to obtain the highest packing density of 1q, it is preferable to place the TA-5 alloy powder in a can and heat it to 500 to 800° C. and hot press under vacuum at a pressure lower than 10 −3 Torr or under an inert gas atmosphere. As a result, the theoretical density ratio reaches 95%. Prior to hot pressing, the laminated gold alloy powder may be cold compacted. As the hot extrusion press at the process opening), hot isostatic extrusion is suitable. If hot extrusion is carried out under the condition that t≦w/3 exists between the wall thickness t and the width W of the extruded product at the process opening), a thin flat plate with anisotropy in the thickness direction can be obtained. magnets can be manufactured. [Function] The above manufacturing method will be described below with reference to the drawings. As described above, the powder of the R-Fe-B magnet alloy is preferably a quenched ribbon powder produced by ultra-quenching. As shown in FIG. 1, this powder 1 is filled into a can 2. The can 2 has a shape that provides a hollow cylinder, but it goes without saying that if a solid cylindrical shape is to be made, a can of a shape corresponding to the shape can be prepared. The cans are made of materials that can be easily hot-deformed, such as mild steel or pure copper, and the seams are welded or brazed to make them airtight. Cans filled with magnetic alloy powder by any of the above methods are
Put the lid on and attach the lid using a method such as welding. In the case of vibration filling, it is also possible to fill with the lid attached. The filling body thus prepared is then placed in a vacuum chamber to be deaerated, and then the opening 21 is welded and sealed by electron beam welding or the like to form a can seal. The degree of vacuum at this time is 1
It is desirable that the pressure be reduced to o-3 rorr or stronger. The can body is heated to processing temperature by radiation or high frequency induction heating. This can of course be done in the atmosphere. The temperature needs to be 500° C. or higher in view of deformability, and if it is lower than that, processing cracks are likely to occur. Furthermore, at temperatures exceeding 800° C., crystal grains grow significantly and the magnetic properties are impaired. Putting these together, 70
A range of 0 to 750°C is optimal. The heated can body is processed into a pipe of predetermined dimensions by hot extrusion. If it is not hollow, process it into a rod shape. The reason why extrusion processing is performed is that this material has low deformability even under hot conditions and is susceptible to processing cracks, and in order to prevent cracks, it is desirable to use a molding method that applies compressive stress. Hot isostatic extrusion is particularly effective in preventing cracking. FIG. 2 shows this process being performed on the hollow can body obtained as described above. The heated can sealing body 3 is placed in the container 5, and the die 8A is pushed by the stem 6 (in the direction of the arrow from the left in the figure).
This is formed between the pipe 9 and the mandrel 8B, and is extruded as a pipe 9 (toward the right in the figure). If a medium 7 that is viscous and incompressible at the processing temperature, such as heat-resistant grease, is sealed in the container 5 to seal the joint of the mold, the space volume inside the container will be reduced by the movement of the stem 6. As a result, high hydrostatic pressure is generated within the medium. This hydrostatic pressure acts as a compressive stress on the entire surface of the can sealing body 3, and can prevent cracking due to its deformation. The height of the hydrostatic pressure in this case is 3,000 to 10,
000 Kg/cri is appropriate; pressures lower than this are less effective in preventing cracking, and pressures higher than this will not allow the strength of the mold to withstand. In addition, hydrostatic extrusion has the effect that the medium exists as a thin film between the goo and the workpiece, and between the mandrel and the workpiece, and acts as a lubricant to prevent direct contact between them, reducing the coefficient of friction. Therefore, hot isostatic extrusion is particularly advantageous when producing 1q of thin-walled, small-diameter pipe-like products. In conventional glass-lubricated extrusion, this frictional work increases, so the limits of the pipe that can be obtained are a minimum diameter of 251Nr1 and a minimum wall thickness of 3M. To take advantage of the advantages of R-Fe-B magnets, the minimum diameter is 15 m and the minimum wall thickness is 11 II! If we want to make a pipe with R1 size, conventional methods require an additional process such as hot rolling, but with hot isostatic extrusion, such a small-diameter, thin-walled pipe can be formed in one step. As described above, since the axis of easy magnetization is perpendicular to the flow direction during plastic deformation, this extrusion creates a structure with anisotropy in the radial direction of the pipe. The resulting tape 9 is cut to a predetermined length, the remaining can material inside and outside is removed, and then magnetized to produce an anisotropic magnet with radial magnetic poles. Removal of the can material may take place prior to cutting, or optionally after magnetization, but is advantageously carried out between cutting and magnetization as described above. The above is a case of manufacturing a ring-shaped anisotropic magnet, which is the most frequently requested case, and the anisotropic magnet of the present invention. The manufacturing method can also be used to manufacture arc segments with circular arc cross sections and flat anisotropic magnets. Arc-shaped items can also be cut by ring cutting (q), so when it comes to manufacturing flat plate-shaped items, prepare a can seal using a rectangular parallelepiped can, and when extruding it, the rolling reduction in the thickness direction is By selecting a die shape that greatly reduces the rolling reduction in the width direction, most of the easy magnetization axes can be aligned in the thickness direction. This can be done as shown by the change in A-+8 in Fig. , by selecting dimensions such that the thickness t is ⅓ or less of the width W.
【実施例］
Ｎ’ １３Ｆｅ８２．７Ｂ ４．３の組成の磁石合金を
超急冷して得た厚さ２０μのリボンを粉砕して、大きざ
約２００μのフレーク状粉末を得た。
板厚２！Ｗｒｉの軟鋼で、外径５０ｍ、内径２０ｍ、長
さ１５０履の管状で上部が開放された缶を用意し、上記
の磁石合金の粉末を入れ、３トン／ｃｒＡの圧力を加え
て冷間プレスしたのら、蓋を気密に溶接することにより
、第１図に示すような充填体を得た。
これを真空槽に入れ、１０−３Ｔｏｒｒの減圧下に３０
分間おいたのち、開口部を電子ビーム溶接して密閉する
ことにより缶封体とした。
この缶封体を大気中の高周波誘導加熱により７５０℃に
昇温し、２分間保持したのち、第２図に示すような熱間
静水圧押出しプレスにより、外径２２ｍ１内径２０＃（
従って肉厚１Ｍｒ１）のパイプを成形した。 このとき
の静水圧は４，６０ＯＮ！？／ ｃｒＡ、押出し速度は
ステム移動速度２０Ｍ／秒とした。
押し出されたパイプから長さ１５Ｍのリングを切り出し
、内面、外面を０．２−ずつ研削して缶材料を除去した
。 ｌａ石材料にはワレは生じていなかった。
これを半径方向に磁化して永久磁石とし、その磁気特性
を測定して、最大エネルギー積（Ｂ Ｈ） ｍａｘの値
３５ＭＧＯｅを１１だ。
■発明の効果】
本発明の製造方法に従えば、Ｒ−Ｆｅ−Ｂ系磁石合金の
弱点でめった易酸化性や難加工性に伴う問題が回避でき
、大気中で１工程の塑性変形を行なうことによって、ワ
レの発生を防いで、所望の寸法の成形品を得ることがで
きる。 従ってこの方法は、とくに小径のもの、薄肉の
ものを製造するのに適している。
得られる磁石は異方性が高く、磁気特性のすぐれたもの
であるにもかかわらず、製造コストは従来技術によるも
のより大幅に低減できる。[Example] A ribbon having a thickness of 20 μm obtained by ultra-quenching a magnetic alloy having a composition of N' 13Fe82.7B 4.3 was pulverized to obtain flaky powder with a size of about 200 μm. Board thickness 2! Prepare a tubular can made of Wri mild steel with an open top and an outer diameter of 50 m, an inner diameter of 20 m, and a length of 150 shoes.The above magnetic alloy powder was poured into the can, and a pressure of 3 tons/crA was applied to the can, which was then cold pressed. Thereafter, the lid was welded airtight to obtain a filling body as shown in FIG. 1. This was placed in a vacuum chamber and heated for 30 minutes under a reduced pressure of 10-3 Torr.
After waiting for a minute, the opening was sealed by electron beam welding to form a can seal. The can body was heated to 750°C by high-frequency induction heating in the atmosphere, held for 2 minutes, and then heated to a temperature of 22 m in outer diameter and 20 # in inner diameter using a hot isostatic extrusion press as shown in Figure 2.
Therefore, a pipe with a wall thickness of 1 Mr1) was molded. The hydrostatic pressure at this time was 4,60 ON! ? / crA, and the extrusion speed was a stem movement speed of 20 M/sec. A ring with a length of 15M was cut from the extruded pipe, and the inner and outer surfaces were ground by 0.2 to remove the can material. No cracks were observed in the laminated stone material. This was magnetized in the radial direction to become a permanent magnet, and its magnetic properties were measured, and the value of the maximum energy product (B H) max was 35MGOe, which was 11. ■Effects of the invention: According to the manufacturing method of the present invention, problems associated with the weak points of R-Fe-B magnet alloys such as oxidizability and difficult workability can be avoided, and plastic deformation is performed in one step in the atmosphere. By doing so, it is possible to prevent cracking and obtain a molded product with desired dimensions. Therefore, this method is particularly suitable for manufacturing small-diameter and thin-walled products. Although the resulting magnet has high anisotropy and excellent magnetic properties, the manufacturing cost can be significantly reduced compared to conventional techniques.
図面はいずれも本発明の異方性磁石の製造方法の工程を
説明するためのものであって、第１図は、工程イ）にお
いて磁石合金粉末を缶に充填したところを示す縦断面で
あり、第２図は、工程口）において、缶封体を熱間静水
圧押出しプレスによりパイプに成形しているところを示
す、やはり縦断面図である。
第３図は、本発明に従って平板状の異方性磁石を製造す
る場合の熱間押出し成形の条件を説明するための斜視図
であって、Ａは押出し前の、Ｂは押出し後の材料の形状
を、それぞれ示す。
１・・・磁石合金粉末
２・・・缶
２１・・・開口部
３・・・缶封体
５・・・コンテナー ６・・・ステム７・・・媒
体
８Ａ・・・ダイ ８Ｂ・・・マンドレル９・
・・パイプ
特許出願人 大同特殊鋼株式会社
代理人 弁理士 須 賀 総 夫
第１図
第３図
Ａ ＢThe drawings are all for explaining the steps of the method for manufacturing an anisotropic magnet of the present invention, and FIG. 1 is a longitudinal cross-section showing a can filled with magnet alloy powder in step a). , FIG. 2 is also a longitudinal cross-sectional view showing the can seal being formed into a pipe by hot isostatic extrusion press at the process opening. FIG. 3 is a perspective view for explaining the conditions of hot extrusion when producing a flat anisotropic magnet according to the present invention, in which A is a perspective view of the material before extrusion, and B is a perspective view of the material after extrusion. The shapes are shown respectively. 1... Magnet alloy powder 2... Can 21... Opening 3... Can enclosure 5... Container 6... Stem 7... Medium 8A... Die 8B... Mandrel 9・
... Pipe patent applicant Daido Steel Co., Ltd. Agent Patent attorney Souo Suga Figure 1 Figure 3 A B
Claims (6)
ａ系の希土類元素をあらわす。］異方性磁石の製造方法 イ）Ｒ−Ｆｅ−Ｂ系磁石合金の粉末を缶内に充填し、真
空吸引下に気密に密封をする工程、ロ）磁石合金の粉末
を封入した缶を加熱し、熱間押出しプレスにより押出し
成形し、それによって結晶異方性を付与する工程、およ
び ハ）押出し成形体から所定の形状の磁石材料を切り出し
、缶材料を除去して磁化する工程。(1) R-Fe-B system [R is L] consisting of the following steps
Represents an a-based rare earth element. ] Manufacturing method of anisotropic magnet A) Step of filling R-Fe-B magnet alloy powder into a can and airtightly sealing it under vacuum suction B) Heating the can filled with magnet alloy powder and (c) extrusion molding using a hot extrusion press, thereby imparting crystal anisotropy; and c) cutting a magnet material of a predetermined shape from the extrusion molded body, removing the can material, and magnetizing it.
する手段として振動充填を行なう請求項１の製造方法。2. The manufacturing method according to claim 1, wherein in step (a), vibration filling is performed as a means for filling the magnetic alloy powder into the can.
するに当り、冷間プレスを行なって高い充填密度を得る
請求項１の製造方法。3. The manufacturing method according to claim 1, wherein in step (a), cold pressing is performed to obtain a high packing density when filling the magnetic alloy powder into the can.
するに当り、１０＾−＾３Ｔｏｒｒより低圧の真空下ま
たは不活性ガス雰囲気下に５００〜８００℃に加熱して
ホットプレスを行なって高い充填密度を得る請求項１の
製造方法。(4) In step A), when filling the can with magnetic alloy powder, hot pressing is performed by heating it to 500 to 800°C under a vacuum at a pressure lower than 10^-^3 Torr or under an inert gas atmosphere. The manufacturing method according to claim 1, wherein a high packing density is obtained.
静水圧押出しを行なう請求項１の製造方法。5. The manufacturing method according to claim 1, wherein in step (b), hot isostatic extrusion is carried out as a hot extrusion press.
との間にｔ≦ｗ／３の関係が得られる条件で熱間押出し
加工を行ない、肉厚方向に異方性をもつ薄肉形状磁石を
得る請求項１の製造方法。(6) In process b), the wall thickness t and width w of the extruded product
2. The manufacturing method according to claim 1, wherein the hot extrusion process is carried out under conditions such that the relationship t≦w/3 is obtained, thereby obtaining a thin-walled magnet having anisotropy in the thickness direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63075614A JPH01248503A (en) | 1988-03-29 | 1988-03-29 | Manufacture of r-fe-b family anisotropy magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63075614A JPH01248503A (en) | 1988-03-29 | 1988-03-29 | Manufacture of r-fe-b family anisotropy magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01248503A true JPH01248503A (en) | 1989-10-04 |
Family
ID=13581263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63075614A Pending JPH01248503A (en) | 1988-03-29 | 1988-03-29 | Manufacture of r-fe-b family anisotropy magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01248503A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0392799A1 (en) * | 1989-04-14 | 1990-10-17 | Daido Tokushuko Kabushiki Kaisha | Method and apparatus for producing anisotropic rare earth magnet |
| JPH04148508A (en) * | 1990-10-11 | 1992-05-21 | Sanyo Special Steel Co Ltd | Method of producing uniaxially anisotropic rare-earth magnet |
| JPH097871A (en) * | 1995-06-19 | 1997-01-10 | Mando Mach Co Ltd | Permanent magnet preparation |
| JP2003533017A (en) * | 2000-05-04 | 2003-11-05 | アドヴァンスト・マテリアルズ・コーポレイション | Method of manufacturing high energy product anisotropic magnet by extrusion |
| WO2014065188A1 (en) * | 2012-10-23 | 2014-05-01 | トヨタ自動車株式会社 | Rare-earth-magnet production method |
| DE102015113976A1 (en) | 2014-08-25 | 2016-02-25 | Toyota Jidosha Kabushiki Kaisha | Method of making a rare earth magnet |
| US10002695B2 (en) | 2014-10-03 | 2018-06-19 | Toyota Jidosha Kabushiki Kaisha | Method for manufacturing rare-earth magnets |
-
1988
- 1988-03-29 JP JP63075614A patent/JPH01248503A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0392799A1 (en) * | 1989-04-14 | 1990-10-17 | Daido Tokushuko Kabushiki Kaisha | Method and apparatus for producing anisotropic rare earth magnet |
| JPH04148508A (en) * | 1990-10-11 | 1992-05-21 | Sanyo Special Steel Co Ltd | Method of producing uniaxially anisotropic rare-earth magnet |
| JPH097871A (en) * | 1995-06-19 | 1997-01-10 | Mando Mach Co Ltd | Permanent magnet preparation |
| JP2003533017A (en) * | 2000-05-04 | 2003-11-05 | アドヴァンスト・マテリアルズ・コーポレイション | Method of manufacturing high energy product anisotropic magnet by extrusion |
| WO2014065188A1 (en) * | 2012-10-23 | 2014-05-01 | トヨタ自動車株式会社 | Rare-earth-magnet production method |
| JP2014103386A (en) * | 2012-10-23 | 2014-06-05 | Toyota Motor Corp | Manufacturing method of rare-earth magnet |
| DE102015113976A1 (en) | 2014-08-25 | 2016-02-25 | Toyota Jidosha Kabushiki Kaisha | Method of making a rare earth magnet |
| JP2016046440A (en) * | 2014-08-25 | 2016-04-04 | トヨタ自動車株式会社 | Method for manufacturing rare earth magnet |
| US10062504B2 (en) | 2014-08-25 | 2018-08-28 | Toyota Jidosha Kabushiki Kaisha | Manufacturing method of rare-earth magnet |
| US10002695B2 (en) | 2014-10-03 | 2018-06-19 | Toyota Jidosha Kabushiki Kaisha | Method for manufacturing rare-earth magnets |
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