JPH062067A - Manufacture of iron-chromium sintered soft magnetic material - Google Patents
Manufacture of iron-chromium sintered soft magnetic materialInfo
- Publication number
- JPH062067A JPH062067A JP15941992A JP15941992A JPH062067A JP H062067 A JPH062067 A JP H062067A JP 15941992 A JP15941992 A JP 15941992A JP 15941992 A JP15941992 A JP 15941992A JP H062067 A JPH062067 A JP H062067A
- Authority
- JP
- Japan
- Prior art keywords
- sintering
- iron
- soft magnetic
- magnetic material
- temp
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高い磁気的特性を必要
とするセンサ、プランジャ等に用いられる軟磁性材料の
製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a soft magnetic material used for sensors, plungers, etc., which require high magnetic properties.
【０００２】[0002]
【従来の技術】鉄−クロム系焼結ステンレス鋼の耐食性
および軟磁気特性を高めるためには、鋼中のＯ，Ｎ，Ｃ
含有量を低くし、焼結密度を高くすることが求められ
る。これらは原料粉末組成や焼結条件により大きく影響
されるため、その特性向上のため種々の方策が従来取ら
れてきた。2. Description of the Related Art In order to improve the corrosion resistance and soft magnetic properties of iron-chromium sintered stainless steel, O, N, C in the steel is to be improved.
It is required to reduce the content and increase the sintered density. Since these are greatly influenced by the raw material powder composition and the sintering conditions, various measures have been conventionally taken to improve the characteristics.
【０００３】一般に、ステンレス鋼を焼結する場合、雰
囲気中に窒素が存在するとCr成分が窒化して焼結ステン
レス鋼の磁気特性が劣化するばかりでなく、耐食性も低
下するため、Ar等の不活性ガス雰囲気や水素雰囲気中で
の焼結、あるいは真空中での焼結が考えられる。しか
し、不活性ガスや水素ガスの使用は高価であり、生産的
ではなく、真空中で焼結する場合には、焼結時のCr蒸発
を抑えるために、Arや水素等のガスを一定量分圧として
導入する方法が取られている。Generally, in the case of sintering stainless steel, when nitrogen is present in the atmosphere, the Cr component is nitrided and the magnetic characteristics of the sintered stainless steel are deteriorated, and the corrosion resistance is also deteriorated. Sintering in an active gas atmosphere or hydrogen atmosphere, or sintering in a vacuum can be considered. However, the use of inert gas or hydrogen gas is expensive and not productive.When sintering in vacuum, a certain amount of gas such as Ar or hydrogen is used to suppress evaporation of Cr during sintering. The method of introducing it as a partial pressure is adopted.
【０００４】Crは易酸化性元素であるため粉末表面に酸
化物が形成され、粉末のＯ含有量が0.25％程度になるこ
とは避けられない。これがため脱酸素の目的で、粉末成
形時に0.5 ％を超える黒鉛を添加する方法が行われてい
るが、脱酸効果はあるものの焼結後に炭素成分が残存
し、これは軟磁性材料として不適当であり、また分圧と
して水素が導入される場合には、脱酸材として添加する
黒鉛成分と反応し、脱酸効果を減ずる役割を果たすの
で、その制御は困難であった。Since Cr is an easily oxidizable element, it is unavoidable that an oxide is formed on the powder surface and the O content of the powder becomes about 0.25%. Therefore, for the purpose of deoxidation, a method of adding more than 0.5% graphite at the time of powder molding is used, but although it has a deoxidizing effect, the carbon component remains after sintering, which is unsuitable as a soft magnetic material. Moreover, when hydrogen is introduced as a partial pressure, it reacts with the graphite component added as a deoxidizing agent and plays a role of reducing the deoxidizing effect, so that its control is difficult.
【０００５】また、真空中で1260℃以上の焼結温度によ
り焼結することにより、Cr酸化物の解離を図り、焼結後
の急冷によって再酸化を防ぐ方法も行われているが、焼
結温度が高いため、製造コストの上昇は避けられず、ま
た製品の寸法安定性が劣る結果となるという問題があっ
た。[0005] Further, a method of dissociating Cr oxides by sintering at a sintering temperature of 1260 ° C or higher in vacuum and preventing reoxidation by rapid cooling after sintering is also used. Since the temperature is high, there is a problem that the manufacturing cost is inevitably increased and the dimensional stability of the product is deteriorated.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上述した従
来技術の問題を解決して、Cr含有量が高い鉄−クロム系
焼結ステンレス鋼中のＯ，Ｎ，Ｃ含有量を低減するとと
もに高密度化を図ることによって軟磁性材料として用い
るのに必要な磁気特性を有し、しかも、耐食性の高い鉄
−クロム系焼結軟磁性材料を低製造コストで安定して製
造し得る製造方法を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and reduces the O, N, and C contents in iron-chromium sintered stainless steel having a high Cr content. A manufacturing method capable of stably manufacturing an iron-chromium sintered soft magnetic material having the magnetic properties required for use as a soft magnetic material by increasing the density and having high corrosion resistance at a low manufacturing cost. The purpose is to provide.
【０００７】[0007]
【課題を解決するための手段】本発明は、低濃度のＯ，
Ｎ，Ｃを有する従来の鉄−クロム原料粉を用いながら圧
粉体密度を従来より以上に高める方法を確立し、それに
対応した適正な焼結条件の確立を図ることによって上述
した従来技術の問題を解決したもので、重量比でＣ：0.
03％以下、Ｏ：0.3 ％以下、Ｎ：0.01％以下で、Cr：12
〜22％を主元素として含有するステンレス鋼合金粉に、
黒鉛粉を0.03〜0.10％添加混合し、圧粉成形した後、11
00℃までは真空中で、1100℃から焼結温度まで、および
焼結温度での恒温保持中、また少なくとも焼結温度から
640 ℃までの引き続く冷却過程においては、水素を５〜
200 Torrの分圧で導入した雰囲気で焼結・冷却を行い、
それ以下の室温までの冷却は非酸化性雰囲気で行うもの
である。The present invention provides a low concentration of O,
The problem of the above-mentioned prior art was established by establishing a method for increasing the green compact density more than before while using the conventional iron-chromium raw material powder containing N and C, and establishing appropriate sintering conditions corresponding thereto. This is a solution to the problem, and the weight ratio is C: 0.
03% or less, O: 0.3% or less, N: 0.01% or less, Cr: 12
Stainless steel alloy powder containing ~ 22% as the main element,
Add 0.03 to 0.10% graphite powder, mix and mix, then press
In vacuum up to 00 ° C, from 1100 ° C to sintering temperature, and during isothermal holding at sintering temperature, or at least from sintering temperature
During the subsequent cooling process up to 640 ° C, hydrogen is added to
Sintering and cooling are performed in an atmosphere introduced with a partial pressure of 200 Torr,
Cooling to room temperature below that is performed in a non-oxidizing atmosphere.
【０００８】本発明によれば、焼結温度での恒温保持後
の冷却過程で、焼結温度から850 〜900 ℃までの冷却速
度を２〜３℃／分に制御するのがよい。According to the present invention, the cooling rate from the sintering temperature to 850 to 900 ° C. is preferably controlled to 2 to 3 ° C./minute in the cooling process after the isothermal holding at the sintering temperature.
【０００９】また、本発明によれば、添加する黒鉛の平
均粒度を５〜15μm とするのがよい。Further, according to the present invention, it is preferable that the added graphite has an average particle size of 5 to 15 μm.
【００１０】[0010]
【作用】従来、鉄系粉末に黒鉛を添加混合すると、その
混合鉄系粉末の流動性を低下させて型内への粉末の均一
な充填を妨げると共に、圧粉密度の低下をもたらすもの
とされていたが、本発明の微量黒鉛の添加は、それによ
り基材粉末相互の流れを改善し、均一な充填を図る上で
効果があるとともに、圧粉密度の低下を抑えるという新
たな知見に基づくものである。その効果は黒鉛添加量が
0.03％〜0.10％の範囲内で顕著に認められるものであっ
た。[Function] Conventionally, when graphite is added to and mixed with the iron-based powder, it is considered that the fluidity of the mixed iron-based powder is lowered, the uniform filling of the powder in the mold is hindered, and the green compact density is reduced. However, the addition of a trace amount of graphite of the present invention is based on a new finding that it improves the mutual flow of base powders, is effective in achieving uniform filling, and suppresses the decrease in green compact density. It is a thing. The effect is that the amount of graphite added
It was remarkably observed in the range of 0.03% to 0.10%.
【００１１】黒鉛は粉体表面のCr酸化物を脱酸させるも
のであり、本発明において添加した黒鉛もその効果を果
たすが、添加量が微量のため脱酸反応が終了するまで水
素による黒鉛の損失を少なくするため、昇温時1100℃ま
では真空中処理とし、脱酸反応が終了する1100℃以上で
水素分圧を使用した。また、黒鉛粉があまり微細では脱
酸の反応時間が少なくて効果が薄く、また粗粉過ぎると
焼結後も含有炭素として残留して磁気特性を劣化させる
ため、粒径は５〜15μm が適当であった。[0011] Graphite deoxidizes the Cr oxide on the powder surface, and the graphite added in the present invention also exerts its effect. However, since the addition amount is very small, the graphite deoxidized by hydrogen is used until the deoxidation reaction is completed. In order to reduce the loss, the treatment was carried out in vacuum up to 1100 ° C when the temperature was raised, and the hydrogen partial pressure was used at 1100 ° C or higher at which the deoxidation reaction was completed. Also, if the graphite powder is too fine, the reaction time for deoxidation is short and the effect is small, and if it is too coarse, it remains as contained carbon after sintering and deteriorates the magnetic properties, so a particle size of 5 to 15 μm is appropriate. Met.
【００１２】また焼結温度から850 ℃ないし900 ℃まで
の冷却過程で２〜３℃／分の冷却速度に制御することに
よって、真空中での昇温時に蒸発した表面のCr成分を内
部からの拡散で補い、一層の耐食性の向上を図るととも
に、水素による十分な脱炭を図ることができた。Further, by controlling the cooling rate at 2 to 3 ° C./min in the cooling process from the sintering temperature to 850 ° C. to 900 ° C., the Cr component on the surface evaporated at the time of temperature rise in vacuum is removed from the inside. By supplementing with diffusion, the corrosion resistance was further improved, and sufficient decarburization with hydrogen could be achieved.
【００１３】[0013]
（実施例１）重量比でＯ：0.20％、Ｎ：0.008 ％、Ｃ：
0.007 ％で、Cr：12.5％を含むSUS410 Ｌの−100 メッ
シュ粉末を主原料とし、黒鉛無添加のもの、および黒鉛
を0.05％、0.10％、0.15％添加したものについて、成形
圧力７tonf／cm2 で成形し、1170℃で１時間、水素ガス
を10 Torr 分圧として導入した真空中で焼結し、種々の
冷却条件で冷却した。得られた材料の磁気特性（インダ
クタンス比透磁率μLを比較し表１に示した。(Example 1) O: 0.20% by weight, N: 0.008%, C:
Molding pressure of 7 tonf / cm 2 for SUS410L-100 mesh powder containing 0.001% Cr: 12.5% with no graphite added and graphite added with 0.05%, 0.10% and 0.15% And sintered in a vacuum in which hydrogen gas was introduced at a partial pressure of 10 Torr at 1170 ° C. for 1 hour, and cooled under various cooling conditions. The magnetic properties (inductance relative permeability μ L) of the obtained materials are compared and shown in Table 1.
【表１】 [Table 1]
【００１４】（実施例２）重量比で、Ｏ：0.19％、Ｎ：
0.008 ％、Ｃ：0.009 ％で、Cr：16.8％を含むSUS430Ｌ
の−100 メッシュ粉末を主原料とし、黒鉛無添加のも
の、黒鉛を0.05％添加したものについて、実施例１と同
様な条件で焼結した。その結果を表１に示した。(Example 2) O: 0.19% by weight ratio, N:
SUS430L with 0.008%, C: 0.009% and Cr: 16.8%
The -100 mesh powder of No. 1 as a main raw material, no graphite added, and 0.05% graphite added were sintered under the same conditions as in Example 1. The results are shown in Table 1.
【００１５】表１から明らかなように、本発明により黒
鉛を0.03〜0.10％の微量添加し、本発明により特定した
焼結条件で焼結したものが優れた磁気特性を示した。As is apparent from Table 1, those obtained by adding a trace amount of graphite of 0.03 to 0.10% according to the present invention and sintering under the sintering conditions specified by the present invention showed excellent magnetic characteristics.
【００１６】[0016]
【発明の効果】本発明によれば、1150〜1200℃程度の比
較的低い温度での焼結により、容易に、かつ低コストで
磁気特性の優れた軟磁性材料を製造することができると
ともに、黒鉛の微量添加により寸法変化量を低下できる
ことによって寸法精度の良い部品を製造できる効果をも
たらした。According to the present invention, it is possible to easily and inexpensively produce a soft magnetic material having excellent magnetic properties by sintering at a relatively low temperature of about 1150 to 1200 ° C. By adding a small amount of graphite, the amount of dimensional change can be reduced, which has the effect of producing parts with high dimensional accuracy.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｃ２２Ｃ 38/18 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Office reference number FI technical display location C22C 38/18
Claims (3)
下、Ｏ：0.3 ％以下、Ｎ：0.01％以下を含有するフェラ
イト系ステンレス鋼粉末100 に対して、黒鉛粉末を0.03
〜0.10％添加混合し、圧粉成形後、真空中で焼結を行う
に際して、1100℃から焼結温度までの昇温時、焼結温度
での恒温保持中および焼結温度から少なくとも640 ℃ま
での冷却の間、水素を５〜200 Torrの分圧で導入するこ
とを特徴とする鉄−クロム系焼結軟磁性材料の製造方
法。1. A ferritic stainless steel powder containing Cr: 12 to 22%, C: 0.03% or less, O: 0.3% or less, and N: 0.01% or less by weight of graphite powder to 0.03%.
~ 0.10% added and mixed, and after compacting and sintering in vacuum, when heating from 1100 ℃ to the sintering temperature, while maintaining a constant temperature at the sintering temperature, and from the sintering temperature to at least 640 ℃ A method for producing an iron-chromium based sintered soft magnetic material, which comprises introducing hydrogen at a partial pressure of 5 to 200 Torr during cooling.
焼結温度から850 〜900 ℃までの冷却速度を２〜３℃／
分に制御することを特徴とする特許請求の範囲第１項記
載の鉄−クロム系焼結軟磁性材料の製造方法。2. In the cooling process after the isothermal holding at the sintering temperature,
Cooling rate from sintering temperature to 850-900 ℃ is 2-3 ℃ /
The method for producing an iron-chromium system sintered soft magnetic material according to claim 1, wherein the method is controlled according to the above.
粉末であることを特徴とする特許請求の範囲第１項記載
の鉄−クロム系焼結軟磁性材料の製造方法。3. The method for producing an iron-chromium sintered soft magnetic material according to claim 1, wherein the graphite powder is a graphite powder having an average particle size of 5 to 15 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15941992A JP2766427B2 (en) | 1992-06-18 | 1992-06-18 | Method for producing iron-chromium sintered soft magnetic material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15941992A JP2766427B2 (en) | 1992-06-18 | 1992-06-18 | Method for producing iron-chromium sintered soft magnetic material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH062067A true JPH062067A (en) | 1994-01-11 |
| JP2766427B2 JP2766427B2 (en) | 1998-06-18 |
Family
ID=15693335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15941992A Expired - Fee Related JP2766427B2 (en) | 1992-06-18 | 1992-06-18 | Method for producing iron-chromium sintered soft magnetic material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2766427B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6533996B2 (en) | 2001-02-02 | 2003-03-18 | The Boc Group, Inc. | Method and apparatus for metal processing |
-
1992
- 1992-06-18 JP JP15941992A patent/JP2766427B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6533996B2 (en) | 2001-02-02 | 2003-03-18 | The Boc Group, Inc. | Method and apparatus for metal processing |
| US7018584B2 (en) | 2001-02-02 | 2006-03-28 | The Boc Group, Inc. | Method and apparatus for metal processing |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2766427B2 (en) | 1998-06-18 |
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