JP2766427B2 - Method for producing iron-chromium sintered soft magnetic material - Google Patents
Method for producing iron-chromium sintered soft magnetic materialInfo
- Publication number
- JP2766427B2 JP2766427B2 JP15941992A JP15941992A JP2766427B2 JP 2766427 B2 JP2766427 B2 JP 2766427B2 JP 15941992 A JP15941992 A JP 15941992A JP 15941992 A JP15941992 A JP 15941992A JP 2766427 B2 JP2766427 B2 JP 2766427B2
- Authority
- JP
- Japan
- Prior art keywords
- sintering
- soft magnetic
- magnetic material
- temperature
- chromium
- 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.)
- Expired - Fee Related
Links
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 for manufacturing a soft magnetic material used for a sensor, a plunger, and the like that 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
It is required to reduce the content and increase the sintering density. Since these are greatly affected by the composition of the raw material powder and the sintering conditions, various measures have conventionally been 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, when sintering stainless steel, if nitrogen is present in the atmosphere, the Cr component is nitrided, which not only deteriorates the magnetic properties of the sintered stainless steel but also lowers its corrosion resistance. Sintering in an active gas atmosphere or a hydrogen atmosphere, or sintering in a vacuum is considered. However, the use of inert gas or hydrogen gas is expensive and is not productive.When sintering in a vacuum, a certain amount of gas such as Ar or hydrogen is used to suppress evaporation of Cr during sintering. A method of introducing a partial pressure is used.
【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。[0004] Since Cr is an easily oxidizable element, an oxide is formed on the powder surface, and it is inevitable that the O content of the powder becomes about 0.25%. For this reason, for the purpose of deoxidation, a method of adding more than 0.5% of graphite at the time of powder molding has been used. However, although there is a deoxidizing effect, a carbon component remains after sintering, which is unsuitable as a soft magnetic material. When hydrogen is introduced as a partial pressure, it reacts with the graphite component added as a deoxidizing agent and plays a role in reducing the deoxidizing effect, so that its control was 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 oxide by sintering in a vacuum at a sintering temperature of 1260 ° C or higher to prevent re-oxidation by rapid cooling after sintering is also performed. Since the temperature is high, there is a problem that an increase in the production cost is inevitable 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。SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and reduces the O, N, 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 high magnetic resistance necessary 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。SUMMARY OF THE INVENTION The present invention provides a method for reducing the concentration of O,
Establishing a method for increasing the green compact density more than before using a conventional iron-chromium raw material powder having N and C, and establishing appropriate sintering conditions corresponding to the method to solve the above-mentioned problems of the prior art. Is solved, 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 main element,
After adding and mixing 0.03 to 0.10% of graphite powder and compacting,
Up to 00 ° C in vacuum, from 1100 ° C to sintering temperature, and while maintaining constant temperature at sintering temperature, and at least from sintering temperature
In the subsequent cooling process down to 640 ° C.,
Sintering and cooling in an atmosphere introduced with a partial pressure of 200 Torr,
Cooling to room temperature below that temperature 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, it is preferable to control the cooling rate from the sintering temperature to 850 to 900 ° C. at a rate of 2 to 3 ° C./min in the cooling process after maintaining the constant temperature 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。According to the present invention, the average particle size of the graphite to be added is preferably 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。Conventionally, if graphite is added to and mixed with an iron-based powder, the fluidity of the mixed iron-based powder is reduced to prevent uniform filling of the powder into the mold and to reduce the green density. However, the addition of the trace amount of graphite of the present invention improves the flow between the base powders thereby, is effective in achieving uniform filling, and is based on a new finding that the reduction of the green density is suppressed. Things. The effect is the amount of graphite added
It was remarkably observed within 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 Cr oxide on the powder surface, and the graphite added in the present invention also exerts its effect. However, the amount of graphite added by hydrogen is small until the deoxidation reaction is completed due to the small amount of addition. In order to reduce the loss, the treatment was carried out in a vacuum up to 1100 ° C. when the temperature was raised, and a partial pressure of hydrogen was used at 1100 ° C. or higher where the deoxidation reaction was completed. 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 carbon contained even after sintering and deteriorates magnetic properties. 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 a rate of 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 raising the temperature in vacuum is reduced from the inside. This was supplemented by diffusion to further improve the corrosion resistance and to achieve sufficient decarburization with hydrogen.
【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%, N: 0.008%, C:
The main pressure was -100 mesh powder of SUS410L containing 0.007% and Cr: 12.5%, with no graphite added, and with 0.05%, 0.10% and 0.15% of graphite added, a molding pressure of 7 tonf / cm 2. And sintered at 1170 ° C. for 1 hour in a vacuum in which hydrogen gas was introduced at a partial pressure of 10 Torr, and cooled under various cooling conditions. The resulting comparison the magnetic properties (inductance relative permeability mu L of the material 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, N:
SUS430L containing 0.008%, C: 0.009% and Cr: 16.8%
-100 mesh powder was used as a main material, and no graphite was added, and 0.05% of graphite was added, and 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, a material obtained by adding a small amount of 0.03 to 0.10% of graphite according to the present invention and sintering under the sintering conditions specified by the present invention exhibited excellent magnetic properties.
【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, by sintering at a relatively low temperature of about 1150 to 1200 ° C., a soft magnetic material having excellent magnetic properties can be easily produced at low cost, and Since the amount of dimensional change can be reduced by the addition of a small amount of graphite, there is an effect that a part with high dimensional accuracy can be manufactured.
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 ferrite stainless steel powder 100 containing, by weight, 12 to 22% of Cr, 0.03% or less of C, 0.3% or less of O, and 0.01% or less of N, and 0.03% or less of graphite powder.
~ 0.10% added and mixed, after compacting, when sintering in vacuum, when raising the temperature from 1100 ° C to the sintering temperature, while maintaining the constant temperature at the sintering temperature and at least 640 ° C from the sintering temperature A method for producing a sintered iron-chromium soft magnetic material, characterized in that hydrogen is introduced 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. A cooling process after maintaining a constant temperature at a sintering temperature,
Cooling rate from sintering temperature to 850-900 ° C is 2-3 ° C /
2. The method for producing a sintered iron-chromium soft magnetic material according to claim 1, wherein the iron-chromium-based sintered soft magnetic material is controlled in minutes.
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 according to claim 1, wherein the graphite powder is a graphite powder having an average particle diameter 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 JPH062067A (en) | 1994-01-11 |
| JP2766427B2 true 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) |
Families Citing this family (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
Also Published As
| Publication number | Publication date |
|---|---|
| JPH062067A (en) | 1994-01-11 |
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