JPH01132703A - Manufacture of iron powder for sintering shrinkage body - Google Patents
Manufacture of iron powder for sintering shrinkage bodyInfo
- Publication number
- JPH01132703A JPH01132703A JP63101043A JP10104388A JPH01132703A JP H01132703 A JPH01132703 A JP H01132703A JP 63101043 A JP63101043 A JP 63101043A JP 10104388 A JP10104388 A JP 10104388A JP H01132703 A JPH01132703 A JP H01132703A
- Authority
- JP
- Japan
- Prior art keywords
- iron
- iron powder
- water
- powder
- carbon
- 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
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 103
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 238000005245 sintering Methods 0.000 title abstract description 5
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 38
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052742 iron Inorganic materials 0.000 claims abstract description 27
- 239000002245 particle Substances 0.000 claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000001035 drying Methods 0.000 claims abstract description 14
- 239000000843 powder Substances 0.000 claims description 17
- 238000010298 pulverizing process Methods 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 19
- 229910052760 oxygen Inorganic materials 0.000 abstract description 19
- 239000001301 oxygen Substances 0.000 abstract description 19
- 230000002776 aggregation Effects 0.000 abstract description 5
- 229910001037 White iron Inorganic materials 0.000 abstract description 3
- 238000004220 aggregation Methods 0.000 abstract 2
- 239000012256 powdered iron Substances 0.000 abstract 1
- 238000000034 method Methods 0.000 description 23
- 238000000465 moulding Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 9
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- 239000002609 medium Substances 0.000 description 8
- 238000009826 distribution Methods 0.000 description 7
- 238000000227 grinding Methods 0.000 description 7
- 238000001746 injection moulding Methods 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 229910000805 Pig iron Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000004663 powder metallurgy Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000005054 agglomeration Methods 0.000 description 3
- 238000005261 decarburization Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005238 degreasing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000009689 gas atomisation Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 230000003449 preventive effect Effects 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000009692 water atomization Methods 0.000 description 2
- 241000723438 Cercidiphyllum japonicum Species 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- QMQXDJATSGGYDR-UHFFFAOYSA-N methylidyneiron Chemical compound [C].[Fe] QMQXDJATSGGYDR-UHFFFAOYSA-N 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、微細鉄粉とくに射出焼結成形等焼結収縮体用
として好適な鉄粉の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing fine iron powder, particularly iron powder suitable for use in sintered contract bodies such as injection sinter molding.
従来から、粉末冶金法によって鉄系の焼結体を得る方法
として、自動車等のお品を対象としたプレス成形法が広
く採用されて来た。これは粒径１００虜程度の極低炭素
鉄粉を黒鉛粉と共に強力なプレスによって圧縮し、鉄の
理論密度の８０〜９０％の密度を持つ成形体を得て、高
温で焼結を行い最終成品を得る方法である。以下、この
方法によって得た成形体を本願明細書においてはプレス
収縮体と称する。BACKGROUND ART Conventionally, as a method for obtaining iron-based sintered bodies by powder metallurgy, press forming methods have been widely adopted for products such as automobiles. This is done by compressing ultra-low carbon iron powder with a particle size of about 100 mm using a powerful press together with graphite powder to obtain a compact with a density of 80 to 90% of the theoretical density of iron, which is then sintered at high temperature to finalize it. It is a method of obtaining finished products. Hereinafter, the molded product obtained by this method will be referred to as a press-shrinkable product in the present specification.
また、近年、粉末冶金における成形法の一つとして、射
出成形法が登場した。これは３０虜以下の粒径の微粉を
熱可塑性プラスチックに混ぜ、射出成形機によって成形
し、鉄の５０％前後の密度を持つ成形体を作り、これを
プレス成形法と同様に焼結するが、その際微細鉄粉は凝
集して成形体は太き（収縮し、プレス成形によるものよ
りも密度が上がり、理論密度の９５％前後の成品を得る
ものである。以下、この方法によって得た焼結体を焼結
収縮体と称し、それに適した鉄粉を焼結収縮体用鉄粉と
称す。Furthermore, in recent years, an injection molding method has appeared as one of the molding methods in powder metallurgy. In this method, fine powder with a particle size of 30 mm or less is mixed with thermoplastic plastic and molded using an injection molding machine to create a molded body with a density of around 50% that of iron, which is then sintered in the same way as press molding. At that time, the fine iron powder aggregates and the molded product becomes thick (shrinks) and has a higher density than that obtained by press molding, yielding a product with a density of approximately 95% of the theoretical density. The sintered body is referred to as a sintered contracted body, and the iron powder suitable for the sintered body is referred to as iron powder for sintered contracted bodies.
この高温下の収縮による密度向上を図る焼結収縮体を得
るためには、表面エネルギーの大きな微細粉が必要とな
り、その平均粒径は３０ｐ以下、とくにｌロー以下のも
のが好ましいといわれている。In order to obtain a sintered contracted body that improves density by shrinking at high temperatures, fine powder with high surface energy is required, and it is said that the average particle size is preferably 30p or less, especially 1-rho or less. .
このような微細鉄粉の製造方法として、５００Ｋｇ／ｃ
ｒｄＪ２１上の高圧水に少量の溶鉄を落とし込む水アト
マイズ法と冷媒にガスを用いるガスアトマイズ法等のア
トマイズ法と、また、鉄粉を高温、高圧でＣＯガスと反
応させ、液状のＦｅ（Ｃｏ）ｓ を作り、これを蒸発さ
せて鉄粉を得るカーボニル法等が知られている。As a manufacturing method for such fine iron powder, 500Kg/c
Atomization methods such as water atomization method in which a small amount of molten iron is dropped into high-pressure water on rdJ21, gas atomization method in which gas is used as a refrigerant, and liquid Fe(Co)s by reacting iron powder with CO gas at high temperature and high pressure. The carbonyl method, which produces iron powder and evaporates it to obtain iron powder, is known.
ところが、従来のこれらの微細鉄粉の製造方法において
、水アトマイズ法は粒度分布のバラツキが大きいため歩
留りが低い、ガスアトマイズ法においては冷媒にガスを
用いるので球状になるが、ガスの熱容量が小さいので生
産性は極めて低い、さらにカーボニル法においては極め
て高コストである等の欠点がある。However, in the conventional manufacturing methods of these fine iron powders, the water atomization method has a low yield due to large variations in particle size distribution, and the gas atomization method uses gas as a refrigerant, so the particles become spherical, but the heat capacity of the gas is small. The carbonyl method has drawbacks such as extremely low productivity and extremely high cost.
鉄粉を得る方法として、アメリカン・ソサイアティ・フ
ォー・メタルス発行「メタルス・ハンドブック９編 第
７巻 粉末冶金Ｊ（Ｍｅｔａｌｓ ＨａｎｄｂｏｏｋＮ
ｉｎｔｈ ［Ｅｄｉｔｉｏｎ Ｖｏｌｕｍｅ ７ Ｐｏ
ｗｄｅｒ ！Ｊｅｔａｌｌｕｒｇｙ）に記載されている
ように、鉄を乾式ボールミルによって１００ ｓ前後に
砕いた例がある。As a method for obtaining iron powder, the Metals Handbook, Volume 9, Volume 7, Powder Metallurgy J, published by the American Society for Metals.
inth [Edition Volume 7 Po
Wder! There is an example in which iron was crushed into pieces in about 100 seconds using a dry ball mill, as described in J.D. Jetallurgy.
しかし、乾式ボールミルによる場合、微粉にな−るに従
い粉砕効率が急激に低下する。また、高速のガス気流に
載せ粉体同志または粉体を衝突板に衝突させる方法では
、多量のガスを必要とし、時間当たりの生産性が低く多
量生産をベースとする粉末冶金用としてはコスト的に引
合わない。However, when using a dry ball mill, the grinding efficiency decreases rapidly as the powder becomes finer. In addition, the method of placing powder in a high-speed gas stream or colliding with a collision plate requires a large amount of gas, and the productivity per hour is low, making it costly for powder metallurgy based on mass production. It doesn't match.
これに対して、湿式による粉砕は３０Ｊｓ以下の微細粉
の製造には効果的である。しかし溶媒として水を用いる
場合には、粉砕時及び乾燥時の酸化が問題となる。勿論
、媒体に酸素を溶かさない有機溶媒を用いれば、酸化の
問題は回避される。しがし、有機溶媒はコスト的に不利
である他、防爆対策等作業面での制約が多い。On the other hand, wet grinding is effective for producing fine powder of 30 Js or less. However, when water is used as a solvent, oxidation during grinding and drying becomes a problem. Of course, the problem of oxidation can be avoided if an organic solvent that does not dissolve oxygen is used as the medium. However, organic solvents are not only disadvantageous in terms of cost, but also have many operational restrictions such as explosion-proof measures.
本発明において解決しようとする課題は、焼結収縮体用
鉄粉の製造に、水を媒体とする破砕手段を採用するに際
しての従来問題とした酸化を逆に有効利用しようとする
ことにある。The problem to be solved by the present invention is to effectively utilize oxidation, which was a conventional problem when employing a crushing means using water as a medium for producing iron powder for sintered shrink bodies.
本発明は、低炭素、低酸素を前提とするプレス収縮体用
鉄粉とは異なり、焼結収縮体用の鉄粉は必ずしも炭素及
び酸素を下げる必要がなく、これらの元素が相当量残留
した状態でも充分に実用に供することができるという知
見に基づいて完成したものである。Unlike iron powder for press-contracted bodies, which requires low carbon and low oxygen content, iron powder for sintered-contracted bodies does not necessarily have to be low in carbon and oxygen, and these elements remain in considerable amounts. It was completed based on the knowledge that it can be fully put to practical use even in this state.
すなわち、プレス収縮体の場合、プレス工程では塑性変
形しやすいように低炭素鋼が前提となるし、焼成工程で
は既に収縮しているため、酸素はＣＯガスとして反応除
去されないので、成形前に炭素及び酸素のレベルを下げ
ておく必要がある。In other words, in the case of press-shrinkable bodies, low-carbon steel is required so that it is easily plastically deformed in the pressing process, and since it has already shrunk in the firing process, oxygen is not removed by reaction as CO gas, so carbon is removed before forming. and oxygen levels need to be kept low.
これに対して、焼結収縮体の場合には、焼成加熱中に炭
素と酸素が反応ガスとして逃れた後に収縮するので、こ
れらの元素がバランスをとって残っていれば問題はない
点に着目して完成した。On the other hand, in the case of a sintered contracted body, it contracts after carbon and oxygen escape as reaction gas during firing and heating, so we focused on the point that there is no problem as long as these elements remain in balance. It was completed.
本発明は要約すると、炭素含有量の高い白銑化した鉄を
水を媒体として微粉砕し、これを乾燥、場合によっては
熱処理を施し、鉄中の炭素量に見合った酸素量をもたせ
ることによって、所定の炭素量をもつ焼結体を作るため
の焼結収縮体用の微細鉄粉の製造法である。また、前記
乾燥後の鉄粉に熱処理を施し、炭素含有量０．５％以下
の微細鉄粉の集合体を作り、これを磨砕処理することに
よって、粉の形状を射出成形に適した球状にすることで
ある。In summary, the present invention involves finely pulverizing white iron with a high carbon content using water as a medium, drying it, and subjecting it to heat treatment in some cases to bring an amount of oxygen commensurate with the amount of carbon in the iron. This is a method for producing fine iron powder for use in sintered shrink bodies to produce sintered bodies with a predetermined carbon content. In addition, the iron powder after drying is heat-treated to create an aggregate of fine iron powder with a carbon content of 0.5% or less, and by grinding this, the shape of the powder is changed to a spherical shape suitable for injection molding. It is to do so.
高炭素含有溶鉄としては、炭素を４重量％程度含有する
銑鉄を使うことができ、とくに硫黄、ノリコン。燐等を
事前処理によって除去した高炉銑はとくに好適である。As the high carbon content molten iron, pig iron containing about 4% by weight of carbon can be used, especially sulfur and Noricon. Blast furnace pig iron from which phosphorus and the like have been removed by prior treatment is particularly suitable.
溶融状態の高炭素鉄を噴出水流中に投入すると高炭素鉄
は白銑化し、極めて硬く脆く破砕しやすい３ ｍｍ以下
の粒となる。When molten high-carbon iron is thrown into a jet of water, it turns into white pig iron and becomes extremely hard, brittle, and easily crushed particles of 3 mm or less.
この粒状鉄を破砕する際、最初の破砕すなわち粗破砕は
湿式、乾式のいずれでもよい。When crushing this granular iron, the initial crushing, that is, rough crushing, may be performed either wet or dry.
しかし、破砕効率に差がでる１００ｐ前後から水を媒体
として、振動ボールミル、Ｗ１拌ボールミル等によって
破砕する。破砕後のスラリーは、遠心分離機で脱水し、
脱水ケーキを恒温槽内で乾燥する。However, from around 100p, where a difference in crushing efficiency appears, crushing is performed using a vibrating ball mill, W1 stirring ball mill, etc. using water as a medium. The slurry after crushing is dehydrated using a centrifuge,
Dry the dehydrated cake in a constant temperature bath.
微細鉄粉の酸化は、上記粉砕及び乾燥工程で起こる。そ
の酸化を防ぐ手段として、粉砕媒体である水への防錆剤
の添加と、乾燥雰囲気中の酸素分圧の低下があげられる
。すなわち、水媒体の条件及び乾燥雰囲気の条件によっ
て、乾燥後の鉄粉の酸化量を制御することができる。Oxidation of the fine iron powder occurs during the grinding and drying steps described above. Measures to prevent oxidation include adding a rust preventive to water, which is the grinding medium, and lowering the oxygen partial pressure in the dry atmosphere. That is, the amount of oxidation of the iron powder after drying can be controlled by the conditions of the aqueous medium and the conditions of the drying atmosphere.
鉄粉中に含有している炭素は、その後の加熱処理又は成
形後の焼結において、上記粉砕及び乾燥工程で生じた酸
化物中の酸素が炭酸ガスとして放出され、酸素との未反
応の炭素が残留する。すなわち、鉄粉中の炭素量は一定
であるので、粉砕。During the subsequent heat treatment or sintering after forming, the carbon contained in the iron powder is released as carbon dioxide gas from the oxygen in the oxide produced during the crushing and drying process, and the unreacted carbon with oxygen is released. remains. In other words, the amount of carbon in iron powder is constant, so it is ground.
乾燥工程の酸化量を調整すれば、焼結体の炭素量を制御
できることになる。By adjusting the amount of oxidation in the drying process, the amount of carbon in the sintered body can be controlled.
しかし、破砕が進み粒径が小さ（なると鉄粉の全表面積
は大きくなるので酸化量は大きくなる。However, as crushing progresses and the particle size becomes smaller (as the total surface area of the iron powder increases, the amount of oxidation increases).
とくに１０ｓ以下になると、上述の手段によって酸化を
抑止しても酸素量は鉄粉中の炭素当量を上回り、焼結体
を作っても炭素は残らず酸素の多い劣悪な製品となる。In particular, when the time is less than 10 seconds, even if oxidation is suppressed by the above-mentioned means, the amount of oxygen exceeds the carbon equivalent in the iron powder, and even if a sintered body is made, no carbon remains, resulting in an inferior product containing a lot of oxygen.
したがって、このような場合には、脱炭反応が起こる前
か後で、収縮が起る前で余分な酸素を水素還元する。Therefore, in such cases, excess oxygen is reduced with hydrogen either before or after the decarburization reaction occurs and before shrinkage occurs.
このように、鉄粉中の炭素量にバランスした酸素量を残
すことにより焼結体の炭素量の制御が可能になる。In this way, by leaving an amount of oxygen balanced with the amount of carbon in the iron powder, it becomes possible to control the amount of carbon in the sintered body.
本発明によって得た炭素を含む鉄粉は水を媒体にして成
形することが可能である。また、成形に際しての数％の
有機バインダの添加は、成形時の変形能、グＩＪ ７ン
成形体の強度を上げる点で著しく効果があり、成形及び
焼結前の修正等のハンドリングを著しく容易にする。バ
インダとして水を使用したときは乾燥過程で殆ど除去さ
れ問題はないが、有機バインダを使用した際でも、その
使用量は極めて少量であるので長時間の脱脂は必要ない
。The carbon-containing iron powder obtained by the present invention can be molded using water as a medium. Additionally, the addition of a few percent of an organic binder during molding is extremely effective in increasing the deformability during molding and the strength of the molded product, and it significantly facilitates handling such as corrections before molding and sintering. Make it. When water is used as a binder, most of it is removed during the drying process and there is no problem; however, even when an organic binder is used, the amount used is extremely small, so long degreasing is not necessary.
前述の粉砕して熱処理した鉄粉は、角ぼっており粉体と
しての流動性に欠けるので、射出成形のように流動性を
求められる成形法には必ずしも最適とは言えず、バイン
ダの量を増やす等の手段で、流動性を確保せざるを得な
い。この種の用途には粉体の形状を球に近い形にするこ
とが望ましい。The above-mentioned pulverized and heat-treated iron powder is angular and lacks fluidity as a powder, so it is not necessarily optimal for molding methods that require fluidity, such as injection molding, and the amount of binder must be reduced. There is no choice but to secure liquidity by means such as increasing the amount. For this type of use, it is desirable that the powder be shaped like a sphere.
粉砕した鉄粉は６５０〜７００ ℃に加熱されるとＣＯ
ガスを放出し、脱炭反応が始まる。温度が上がるにつれ
て反応は進み炭素も酸素も下がるが、同時に粒同士が付
着しあう凝集現象が起きる。When crushed iron powder is heated to 650-700℃, CO
Gas is released and the decarburization reaction begins. As the temperature rises, the reaction progresses and the levels of carbon and oxygen decrease, but at the same time a phenomenon of agglomeration occurs in which particles adhere to each other.
したがって、通常には凝集しない温度範囲で脱炭処理を
行い、残りの酸素及び炭素の除去は焼結工程に依存する
ことは前に述べた。Therefore, as previously mentioned, the decarburization treatment is performed in a temperature range that does not normally cause agglomeration, and the removal of the remaining oxygen and carbon depends on the sintering process.
しかし、凝集が進むほどに温度を上げると、粉中の炭素
は下がり軟質の鉄となる。However, if the temperature is raised enough to cause agglomeration, the carbon in the powder will drop and become soft iron.
こうして得られた純度の高い鉄粉は粒子表面の一部が溶
着し焼結体を形成するので、これをほぐしてもとの粒度
に揃える解砕工程が必要となる。Since a part of the particle surface of the high-purity iron powder obtained in this way is welded to form a sintered body, a crushing step is required to loosen this and equalize the original particle size.
当然ながら、解砕に必要なエネルギーは焼結体の固さに
関係し、その固さは熱処理温度の他に原料の粒度によっ
て左右される。たとえば１００−程度の鉄粉であれば、
１０００℃の熱処理でも粒の変形なしに解砕できるが、
２０ｕ！Ｒ程度の微細粉になると熱処理温度を９００℃
にしても解砕に大きなエネルギーが必要となり、粉自体
もかなりの塑性変形をする。Naturally, the energy required for crushing is related to the hardness of the sintered body, and the hardness is influenced by the particle size of the raw material as well as the heat treatment temperature. For example, if it is iron powder of about 100-
Although it can be crushed without deformation of the grains even after heat treatment at 1000℃,
20u! When the powder becomes as fine as R, the heat treatment temperature is increased to 900℃.
However, crushing requires a large amount of energy, and the powder itself undergoes considerable plastic deformation.
粉砕の原理は、衝撃力によって叩き潰す衝撃破砕と、摩
擦力によって信り潰す磨砕に分けられる。The principle of crushing can be divided into impact crushing, which crushes by impact force, and grinding, which crushes by frictional force.
低炭素焼結体を衝撃破砕した例としてボールミルで解砕
したものは角張った形をしている。さらに処理を続ける
と粒はかなり変形を受け、一部は箔状を呈し流動性は悪
くなり、バインダと一緒に流し込む射出成形用の原料と
しては不適当である。As an example of impact crushing of low carbon sintered bodies, those crushed in a ball mill have an angular shape. If the processing continues, the particles undergo considerable deformation, with some becoming foil-like and having poor fluidity, making them unsuitable as raw materials for injection molding, which are poured together with a binder.
しかし、軟らかい鉄粉又はその焼結体を擢り潰すと、粉
体の粒子は球状化する傾向がある。そこで濡る時間を延
長するか、更に強固な焼結体を作り揺り潰し破砕を行え
ば球状化が進む。これは、解砕時に加えられるエネルギ
ーの種類によって鉄粉の塑性変形の仕方が変わるためと
思われる。すなわち、（折撃力を受けると粒子は叩き延
ばされるが、摩擦力を受けると粒子は粒同士で擦り合い
球状化する。このための磨砕装置としては、たとえば挽
臼、償潰機等が挙げられ、これによって球状の微粉状鉄
粉を得ることができる。ただし、この球状化現象は、炭
素含有量０．４重量％以下の鉄で起こり、０．５重量％
を越えた鉄は固いため、上記の処理を行っても塊状化し
がたい。However, when soft iron powder or a sintered body thereof is crushed, the powder particles tend to become spherical. If the wetting time is extended or a stronger sintered body is made and crushed by crushing, spheroidization will proceed. This seems to be because the way the iron powder undergoes plastic deformation changes depending on the type of energy applied during crushing. In other words, (when subjected to a crushing force, the particles are beaten and elongated, but when subjected to a frictional force, the particles rub against each other and become spherical. Examples of grinding equipment for this purpose include a mill, a crusher, etc.) This makes it possible to obtain spherical fine iron powder. However, this spheroidization phenomenon occurs in iron with a carbon content of 0.4% by weight or less, and 0.5% by weight
Since iron exceeding 100% is hard, it is difficult to form lumps even after the above treatment.
実施例 １
高炉より出銑した銑鉄をトーピードカーに受は脱燐処理
を行った後、多量の水流中に落とし粒状の鉄を得た。そ
の成分を表に、粒度分布を第１図に示す。この粒状鉄を
振動ボールミルによって４４ｐ以下に破砕した。その後
１％の防錆剤を添加して、水１に対し、破砕粉ｌの割合
で混ぜ、撹拌ボール粉砕機にて平均９．２ｐに微粉砕し
た。その粒度分布を第２図に示す。Example 1 Pig iron tapped from a blast furnace was dephosphorized using a torpedo car, and then dropped into a large amount of water to obtain granular iron. The components are shown in the table and the particle size distribution is shown in FIG. This granular iron was crushed to 44p or less using a vibrating ball mill. Thereafter, 1% of a rust preventive agent was added and mixed in a ratio of 1 part of crushed powder to 1 part of water, and the mixture was pulverized to an average of 9.2 parts using a stirring ball pulverizer. The particle size distribution is shown in FIG.
上記微細粉スラリを８０℃の大気雰囲気の恒温槽で乾燥
後、水２０％、メチルセルローズ０．５％（いずれも鉄
粉に対する重量比）を加え、内径１２１ｍのパイプに入
れ、つき固めて円柱状のベレットを作った。該ベレット
を乾燥、脱水後、大気と遮断した雰囲気内にて１２００
℃で１時間加熱した結果、密度７．１ｇ／ａｆｆｌの焼
結体を得た。成形前の鉄粉の炭素含有量は３．０％、酸
素は３．２％あったが、焼結体はそれぞれ０．３２％、
０．０５％であった。After drying the above-mentioned fine powder slurry in a constant temperature bath in an air atmosphere at 80°C, 20% water and 0.5% methyl cellulose (both weight ratios to iron powder) were added, and the mixture was poured into a pipe with an inner diameter of 121 m and compacted into a circular shape. I made a columnar beret. After drying and dehydrating the pellet, it was heated for 1200 min in an atmosphere isolated from the atmosphere.
As a result of heating at °C for 1 hour, a sintered body with a density of 7.1 g/affl was obtained. The carbon content of the iron powder before forming was 3.0% and the oxygen content was 3.2%, but the sintered body had a carbon content of 3.0% and an oxygen content of 0.32% and 3.2%, respectively.
It was 0.05%.
実施例２
実施例１で得られた微粉砕、乾燥後の鉄粉をマツフル炉
内にて大気から遮断した雰囲気中８００℃で１時間、引
続いて水素雰囲気中８５０℃で１時間加熱し、嵩密度２
．８の鉄粉集合体を得た。Example 2 The finely pulverized and dried iron powder obtained in Example 1 was heated in a Matsufuru furnace at 800°C for 1 hour in an atmosphere shielded from the atmosphere, and then heated at 850°C for 1 hour in a hydrogen atmosphere. bulk density 2
．． 8 iron powder aggregates were obtained.
上記成形体を５ ｍｍ以下に粗砕後、固定された杆の周
囲に鉢が回転する温体型の粉砕機で解砕した。The above-mentioned molded body was crushed to a size of 5 mm or less, and then crushed using a warm-type crusher in which a bowl rotates around a fixed rod.
こうして得られた微細鉄粉の成分を表に、その粒度分布
を第３図に、電子顕微鏡写真を第４図に示す。The components of the fine iron powder thus obtained are shown in the table, its particle size distribution is shown in FIG. 3, and an electron micrograph is shown in FIG. 4.
原料及び成品の化学組成
微細鉄粉の流動性を調べるために、ホール型フローメー
タを用いて測定した。その結果、熱処理を施さない破砕
のままの鉄粉は５．０ｍｍの径を通らなかったが、本鉄
粉は５，０．ｍｍ径を７秒７５０ｇで通過し、２．６３
ｍｍ径の場合には４０秒ノ５０ｇの結果を得、流動性が
改善されたことが分かった。Chemical Composition of Raw Materials and Finished Products In order to investigate the fluidity of fine iron powder, measurements were taken using a Hall type flow meter. As a result, crushed iron powder without heat treatment did not pass through a diameter of 5.0 mm, but real iron powder did not pass through a diameter of 5.0 mm. mm diameter at 750g in 7 seconds, 2.63
In the case of mm diameter, a result of 50 g in 40 seconds was obtained, indicating that the fluidity was improved.
本発明によって、以下の効果を奏することができる。 The present invention can provide the following effects.
イ、 焼成収縮体用の微細鉄粉が安価に製造できる。B. Fine iron powder for fired contracted bodies can be produced at low cost.
口、 溶融段階以外の工程で、焼成体の炭素中を調整
できる。The carbon content of the fired body can be adjusted in processes other than the melting stage.
ハ、 水を媒体とした成形法が可能となり、有機媒体
による成形法に比較して脱脂工程が簡素化される。C. A molding method using water as a medium becomes possible, and the degreasing process is simplified compared to a molding method using an organic medium.
二、 従来生産性の低いプロセスでしか生産できなか
った射出成形用鉄粉の多量生産が可能となる。Second, it becomes possible to mass-produce iron powder for injection molding, which previously could only be produced using processes with low productivity.
第１図は本発明の実施例１における原料の粒状鉄の粒度
分布、第２図は同本発明の実施例１における微細鉄粉の
粒度分布を示す。
第３図は実施例２における熱処理後儒潰機にて処理した
微細鉄粉の粒度分布を示す。
また、第４図は実施例２における熱処理後償潰機にて処
理した微細鉄粉の粒子形状を示す電子顕微鏡写真（Ｘ３
０００） である。
特許出顆人 吉 川 工 業 株式会社代 理 人
小 堀 益 （ほか２名）第１図
扉オ斗￥立銀舷度夕り僚
一一一→仁１桂ｒ扉凰〕
第２図
粒子径（μｍ）
第６図
成品徘Ｕ旧錬軍分看藺Ｕか年FIG. 1 shows the particle size distribution of granular iron as a raw material in Example 1 of the present invention, and FIG. 2 shows the particle size distribution of fine iron powder in Example 1 of the present invention. FIG. 3 shows the particle size distribution of fine iron powder processed in a crusher after heat treatment in Example 2. In addition, FIG. 4 is an electron micrograph (X3
000). Patent author Yoshikawa Kogyo Co., Ltd. Agent
Masu Kobori (and 2 others) Fig. 1 Tobi Oto ￥ Tachi Gin Kando Yuri Ryo 111 → Jin 1 Katsura r Toibou] Fig. 2 Particle size (μm) Fig. 6 Seihin Wandering U Former Training Army Minami Uka year
Claims (1)
に放流して白銑化した粒鉄を作り、同白銑化した粒鉄を
水を媒体として平均粒径２０μｍ以下に微粉砕した後乾
燥することを特徴とする焼結収縮体用鉄粉の製造方法。 ２、炭素含有量が２重量％以上の高炭素含有溶鉄を水中
に放流して白銑化した粒鉄を作り、同白銑化した粒鉄を
水を媒体として平均粒径２０μｍ以下に微粉砕した後乾
燥して表面に酸化被膜を作り、同微粉状体の集合体を加
熱して炭素含有量０．４％以下に脱炭し、さらに同脱炭
集合体を磨砕することを特徴とする焼結収縮体用鉄粉の
製造方法。[Scope of Claims] 1. High-carbon molten iron with a carbon content of 2% by weight or more is discharged into water to produce white granulated iron, and the white granulated iron is average-sized using water as a medium. A method for producing iron powder for a sintered contracted body, which comprises pulverizing the iron powder to a diameter of 20 μm or less and then drying it. 2. Pour high-carbon molten iron with a carbon content of 2% by weight or more into water to produce whitened iron granules, and pulverize the whitened iron granules to an average particle size of 20 μm or less using water as a medium. After drying, an oxide film is formed on the surface, the aggregate of the fine powder is heated to decarburize the carbon content to 0.4% or less, and the decarburized aggregate is further ground. A method for producing iron powder for sintered shrink bodies.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63101043A JPH0784604B2 (en) | 1987-08-21 | 1988-04-23 | Method for producing iron powder for sinter shrinkage body |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20870087 | 1987-08-21 | ||
| JP62-208700 | 1987-08-21 | ||
| JP63101043A JPH0784604B2 (en) | 1987-08-21 | 1988-04-23 | Method for producing iron powder for sinter shrinkage body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01132703A true JPH01132703A (en) | 1989-05-25 |
| JPH0784604B2 JPH0784604B2 (en) | 1995-09-13 |
Family
ID=26441973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63101043A Expired - Lifetime JPH0784604B2 (en) | 1987-08-21 | 1988-04-23 | Method for producing iron powder for sinter shrinkage body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0784604B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2234527A (en) * | 1989-08-05 | 1991-02-06 | Mixalloy Ltd | Methods of producing metallic powders and metallic powders produced by such methods |
| CN104148657A (en) * | 2014-09-03 | 2014-11-19 | 四川理工学院 | Method for preparing high-compressibility water atomization alloy steel powder through intergranular corrosion |
-
1988
- 1988-04-23 JP JP63101043A patent/JPH0784604B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2234527A (en) * | 1989-08-05 | 1991-02-06 | Mixalloy Ltd | Methods of producing metallic powders and metallic powders produced by such methods |
| CN104148657A (en) * | 2014-09-03 | 2014-11-19 | 四川理工学院 | Method for preparing high-compressibility water atomization alloy steel powder through intergranular corrosion |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0784604B2 (en) | 1995-09-13 |
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