JPH02205655A - Manufacture of high density ferrous sintered body - Google Patents
Manufacture of high density ferrous sintered bodyInfo
- Publication number
- JPH02205655A JPH02205655A JP2519289A JP2519289A JPH02205655A JP H02205655 A JPH02205655 A JP H02205655A JP 2519289 A JP2519289 A JP 2519289A JP 2519289 A JP2519289 A JP 2519289A JP H02205655 A JPH02205655 A JP H02205655A
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- powder
- iron
- elements
- density
- 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 17
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 title abstract description 6
- 239000000843 powder Substances 0.000 claims abstract description 67
- 238000005245 sintering Methods 0.000 claims abstract description 32
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 23
- 239000000956 alloy Substances 0.000 claims abstract description 23
- 239000011812 mixed powder Substances 0.000 claims abstract description 19
- 150000004767 nitrides Chemical class 0.000 claims abstract description 10
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 5
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 5
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- 229910052796 boron Inorganic materials 0.000 claims abstract description 4
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 3
- 229910052735 hafnium Inorganic materials 0.000 claims abstract description 3
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 3
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 3
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 3
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 86
- 229910052742 iron Inorganic materials 0.000 claims description 39
- 150000001247 metal acetylides Chemical class 0.000 claims description 10
- 150000003568 thioethers Chemical class 0.000 claims description 10
- -1 oxides Chemical class 0.000 claims description 8
- 229910052717 sulfur Inorganic materials 0.000 abstract description 12
- 229910052726 zirconium Inorganic materials 0.000 abstract description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 abstract description 2
- 229910052727 yttrium Inorganic materials 0.000 abstract description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 abstract 1
- 230000002265 prevention Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 14
- 229910052799 carbon Inorganic materials 0.000 description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 13
- 229910052760 oxygen Inorganic materials 0.000 description 13
- 239000001301 oxygen Substances 0.000 description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 8
- 239000011593 sulfur Substances 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 238000001746 injection moulding Methods 0.000 description 5
- 239000011800 void material Substances 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 230000008602 contraction Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000012768 molten material Substances 0.000 description 3
- SPIFDSWFDKNERT-UHFFFAOYSA-N nickel;hydrate Chemical compound O.[Ni] SPIFDSWFDKNERT-UHFFFAOYSA-N 0.000 description 3
- 238000004663 powder metallurgy Methods 0.000 description 3
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910001257 Nb alloy Inorganic materials 0.000 description 1
- 241001057981 Puto Species 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 125000005397 methacrylic acid ester group Chemical group 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000001272 pressureless sintering Methods 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【発明の詳細な説明】
「産業上の利用分野」
この発明は、鉄系粉末からなる焼結体の製造方法に係わ
り、特に焼結体相対密度が９８％以上の高密度焼結体が
得られる製造方法に関する。Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for producing a sintered body made of iron-based powder, and particularly to a method for producing a high-density sintered body having a relative density of 98% or more. The present invention relates to a manufacturing method.
「従来技術とその課題」
鉄系材料部品を製造するにあたっては、従来粉末冶金的
手法によって製造することが一般的に行われており、コ
スト的にメリットがあるなどの理由により使用範囲が広
がっている。しかしながら、一般に焼結体はその内部に
ボアが残留しているため、溶製材に比較するとその特性
か劣るものとなる場合が多く、特に伸び、疲労強度、衝
撃値などについては溶製材に比べて低いため、繰り返し
応力や衝撃がかかるような箇所での使用は以下の理由に
より不適となる。すなわち、ボアの残留している焼結部
品（焼結体）では、疲労破壊時にボアからクラックが発
生し、このクラックが大きくなることによって破壊にい
たる。また、この焼結部品に衝撃が加わった場合、ボア
が切り欠き効果をもつことから、ボアが無い場合に比べ
て破壊し易いものとなる。"Prior art and its challenges" Conventionally, powder metallurgy has been commonly used to manufacture ferrous material parts, and its range of use has expanded due to cost advantages and other reasons. There is. However, since sintered bodies generally have bores remaining inside them, their properties are often inferior to those of molten materials, especially in terms of elongation, fatigue strength, impact value, etc. This makes it unsuitable for use in locations subject to repeated stress or impact for the following reasons. That is, in a sintered part (sintered body) in which a bore remains, a crack is generated from the bore during fatigue failure, and this crack becomes large, leading to failure. Furthermore, when an impact is applied to this sintered part, the bore has a notch effect, making it more likely to break than a case without a bore.
したがって、これらの性質が改善されて溶製材並の特性
を有する焼結体の提供が望まれているが、このような焼
結体を得るには、焼結体内部のボアを無くす、すなわち
焼結体の密度を溶製材並にまで上げることが必要である
。しかし、従来の粉末冶金法によって得られる焼結部品
の相対密度はせいぜい９２％程度であり、これより高密
度のものを得るには再圧縮等の工程が必要となる。また
、一般に平均粒径２０μｍ以下に調整した金属粉末を射
出成形すれば高密度焼結体が得られるとされてＮ）るが
、このようにして得られた焼結体でもその焼結体の相対
密度は通常９５〜９６％程度であり、焼結体内部に多数
のボアが存在するものとなる。また１、焼結温度を高く
したり、焼結時間を長くしたりしても、常圧焼結では焼
結体の相対密度を９６％以上とするのは困難であり、溶
製材並の性質を得るには不十分である。Therefore, it is desired to provide a sintered body that has improved these properties and has properties comparable to molten material, but in order to obtain such a sintered body, it is necessary to eliminate the bore inside the sintered body, that is, to sinter the body. It is necessary to increase the density of the aggregate to the same level as that of molten lumber. However, the relative density of sintered parts obtained by conventional powder metallurgy is about 92% at most, and steps such as recompression are required to obtain higher densities. In addition, it is generally said that a high-density sintered body can be obtained by injection molding metal powder whose average particle size is adjusted to 20 μm or less, but even the sintered body obtained in this way is The relative density is usually about 95 to 96%, and a large number of bores are present inside the sintered body. In addition, 1. Even if the sintering temperature is increased or the sintering time is lengthened, it is difficult to achieve a relative density of 96% or higher in the sintered body by pressureless sintering, and the properties are comparable to that of molten material. is insufficient to obtain
ところで、従来の粉末冶金的手法で高密度焼結体が得ら
れない原因としては、原料粉末の粒径が大きく、成形体
に含まれるボアが大きくなるため成形体が焼結時に収縮
しにくいものとなることが挙げられる。したがって、成
形体の密度を９２％以上に上げ、成形体に含まれるボア
の大きさを小さくすれば十分収縮し得るものとなるが、
これでも焼結体相対密度を９５％以上にするには不十分
である。By the way, the reason why a high-density sintered body cannot be obtained using conventional powder metallurgy methods is that the particle size of the raw material powder is large, and the bore contained in the compact becomes large, making it difficult for the compact to shrink during sintering. The following can be mentioned. Therefore, if the density of the molded body is increased to 92% or more and the size of the bore contained in the molded body is reduced, sufficient shrinkage can be achieved.
Even this is insufficient to increase the relative density of the sintered body to 95% or more.
このように成形体密度を上げた場合や、金属射出成形の
ような平均粒径２０μｍ以下の粉末を用いた場合でも、
焼結体相対密度を９６％以上にすることが困難である原
因は、焼結体中の空隙が孤立化し、閉空孔となった後に
もガスを発生し続けるからである。例えば、一般に金属
射出成形で用いられている平均粒径５μｍのカルボニル
鉄粉には、酸素が約０．２重量％、炭素が約０．１重量
％、硫黄が約０．０１重量％含まれており、この粉末を
成形し、水蒸気雰囲気中にて１４００℃で焼結して得ら
れた焼結体中には、酸素が約０．０１重量％、炭素が約
０．０３％重量％、硫黄が約０５０１重量％含まれてい
る。この場合に１４００℃における鉄の酸化物と水素お
よび炭素との平衡は以下のようになる。Even when the density of the compact is increased in this way, or when powder with an average particle size of 20 μm or less is used, such as in metal injection molding,
The reason why it is difficult to increase the relative density of the sintered body to 96% or more is that the voids in the sintered body become isolated and continue to generate gas even after becoming closed pores. For example, carbonyl iron powder with an average particle size of 5 μm, which is generally used in metal injection molding, contains about 0.2% by weight of oxygen, about 0.1% by weight of carbon, and about 0.01% by weight of sulfur. The sintered body obtained by molding this powder and sintering it at 1400°C in a steam atmosphere contains about 0.01% by weight of oxygen, about 0.03% by weight of carbon, Contains approximately 0.501% by weight of sulfur. In this case, the equilibrium between iron oxide and hydrogen and carbon at 1400°C is as follows.
・Ｆ ｅ Ｏ＋ Ｈｔ＃Ｆ ｅ ＋ Ｈｔ。・F e O+ Ht#F e + Ht.
ΔＧ ｏ＝ＲＴ ’Ｉｎ（ａ Ｆ１１’Ｐ ｕｔｏ／
ａ Ｆｌｌｏ−Ｐ Ｈｔ）・ＦｅＯ＋ＣＥＦｅ＋ＣＯ
ΔＧｏ＝ ＲＴ−１ｎ（ａｒｓ・Ｐｃｏ／ａｒｓｏ−
ａｃ）ここで、ΔＧ０は自由エネルギー Ｒは気体定数
、Ｔは絶対温度、ａ Ｆｌ、 ａ ＦｅＯ，ａ ｃは活
量、Ｐｕｔｏ＋Ｐｕｔ、Ｐｃｏはガスの分圧を示す。ａ
ｒｅ、 ａ ＦｅＯを１とし、ａｃがＨｅｎｒｙの法
則に従うとして計算すると、水素！気圧（Ｐ□−１ａｔ
ｍ）のもとでは焼結体内部の孤立空隙内に発生するＨｔ
Ｏのガス圧は０．５気圧であり、ＣＯのガス圧は４２気
圧である。ΔG o=RT 'In(a F11'P auto/
a Flo-P Ht)・FeO+CEFe+CO ΔGo= RT-1n(ars・Pco/arso-
ac) Here, ΔG0 is the free energy, R is the gas constant, T is the absolute temperature, a Fl, a FeO, a c is the activity, Puto+Put, Pco is the partial pressure of the gas. a
re, a If FeO is 1 and ac follows Henry's law, then hydrogen! Atmospheric pressure (P□-1at
m), Ht generated in isolated voids inside the sintered body
The gas pressure of O is 0.5 atm and the gas pressure of CO is 42 atm.
また、焼結体中に含まれている酸素と炭素とが全てＣＯ
ガスとなり、焼結体中のボア内に閉じ込められるとする
と、その圧力は６７気圧となり、ＣＯガスの平衡圧より
高いため焼結体内部の孤立空隙内のガス圧は平衡圧の４
２気圧になる。一方、焼結体内部に存在する数ミクロン
程度の孤立空隙の内面に表面張力の作用によって生じる
表面応力（空隙の収縮の駆動力）σは、
σ＝２γ／ｒ
で表される。ここで、γは鉄の表面エネルギーｒは孤立
空隙の半径である。このσの値は１０気圧程度であり、
焼結体内部の孤立空隙内に発生するガス圧がそれ以上と
なると空隙の収縮が阻害され、これによって焼結体の密
度も上がらなくなる。In addition, all the oxygen and carbon contained in the sintered body are CO
If it becomes a gas and is confined in the bore in the sintered body, its pressure will be 67 atmospheres, which is higher than the equilibrium pressure of CO gas, so the gas pressure in the isolated void inside the sintered body will be 4 atm of the equilibrium pressure.
The pressure becomes 2 atmospheres. On the other hand, the surface stress (driving force for shrinkage of the void) σ caused by the action of surface tension on the inner surface of an isolated void of about several microns that exists inside the sintered body is expressed as σ=2γ/r. Here, γ is the surface energy of iron, r is the radius of the isolated void. The value of this σ is about 10 atm,
If the gas pressure generated in the isolated voids inside the sintered body exceeds this level, the shrinkage of the voids will be inhibited, and the density of the sintered body will therefore not increase.
また、焼結体中に含まれる硫黄も高温で高い蒸気圧を持
つため焼結を阻害することもある。また、粉末粒子表面
に吸着しているＮ、ガスが、空隙の孤立化後に脱着すれ
ば、そのガス圧によって焼結が阻害されることもある。Furthermore, the sulfur contained in the sintered body also has a high vapor pressure at high temperatures, which may inhibit sintering. Further, if N and gas adsorbed on the powder particle surface are desorbed after the voids are isolated, sintering may be inhibited by the gas pressure.
以上のことは、Ｈ２０ガスを除けば他の還元性雰囲気や
不活性雰囲気、真空中でもおこり、焼結体内部の孤立空
隙内で発生するＣＯガス、あるいはＳガス、Ｎ、ガスの
圧力のために焼結体密度が上がらず、焼結体相対密度９
６％以上のものが得られないことになる。Apart from H20 gas, the above can also occur in other reducing atmospheres, inert atmospheres, and vacuum, due to the pressure of CO gas, S gas, N gas, etc. generated in isolated voids inside the sintered body. The density of the sintered body does not increase, and the relative density of the sintered body is 9.
This means that you will not be able to obtain more than 6%.
この発明は上記事実に鑑みてなされたもので、その目的
とするところは、焼結体相対密度が９８％以上の緻密化
された高密度鉄系焼結体を製造し得る方法を提供するこ
とにある。This invention was made in view of the above facts, and its purpose is to provide a method for producing a densified high-density iron-based sintered body having a relative density of 98% or more. It is in.
「課題を解決するための手段」
この発明の高密度鉄系焼結体の製造方法では、鉄系粉末
に焼結温度にて安定である炭化物、酸化物、硫化物、あ
るいは窒化物を生成する元素の単体粉末または該元素を
含む合金粉末の一種以上を添加してなる混合粉末か、あ
るいは上記元素を含有してなる鉄系合金粉末を用意し、
次いで用意した混合粉末あるいは鉄系合金粉末を成形し
、その後焼結して焼結体相対密度９８％以上の鉄系焼結
体を得ることを上記課題の解決手段とした。"Means for Solving the Problems" In the method for producing a high-density iron-based sintered body of the present invention, carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature are generated in the iron-based powder. Prepare an elemental powder of an element, a mixed powder made by adding one or more types of alloy powder containing the element, or an iron-based alloy powder containing the above element,
Next, the prepared mixed powder or iron-based alloy powder is molded and then sintered to obtain an iron-based sintered body having a relative density of 98% or more.
以下、この発明の詳細な説明する。The present invention will be explained in detail below.
まず、鉄系粉末として鉄の単体粉末、鉄の合金粉末を用
意する。ここで、鉄の合金粉末としてはＦｅ−Ｎｉ系合
金やＦｅ−Ｃｏ系合金、Ｆｅ−Ｎｉ−Ｇ。First, a simple iron powder and an iron alloy powder are prepared as iron-based powders. Here, the iron alloy powder includes Fe-Ni alloy, Fe-Co alloy, and Fe-Ni-G.
系などの粉末が使用可能である。また、この鉄系粉末と
しては平均粒径２０μｍ以下のものが好適とされ、特に
１０μｍ以下のものが後述する焼結時の焼′結温度を低
くすることができ、望ましい。It is possible to use powders such as powders. Further, it is preferable that the iron-based powder has an average particle diameter of 20 μm or less, and in particular, 10 μm or less is preferable because it can lower the sintering temperature during sintering, which will be described later.
また、この鉄系粉末を焼結するに際しての焼結温度にて
安定である炭化物、酸化物、硫化物、あるいは窒化物を
生成する元素の単体粉末または該元素を含む合金粉末を
用意する。ここで、焼結温度にて安定である炭化物、酸
化物、硫化物、あるいは窒化物を生成する元素とは、焼
結体内部の孤立する空隙内に発生しあるいは存在する各
種ガスの構成元素、すなわち酸素、炭素、硫黄、窒素な
どと反応し、焼結温度にて安定な化合物を生成する元素
をいい、具体的にはＡｌ、Ｔｉ、Ｚｒ、Ｎｂ。In addition, a single powder of an element that produces carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature at which the iron-based powder is sintered or an alloy powder containing the element is prepared. Here, elements that produce carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature are constituent elements of various gases that occur or exist in isolated voids inside the sintered body, That is, it refers to an element that reacts with oxygen, carbon, sulfur, nitrogen, etc. to form a stable compound at the sintering temperature, and specifically includes Al, Ti, Zr, and Nb.
Ｖ、Ｔａ、Ｈｆ、Ｃｒ、Ｓ ｉ、Ｍｎ、Ｂ、Ｐ、Ｙおよ
び希土類元素などのようにその酸化物、炭化物、硫化物
または窒化物の生成自由エネルギーの低い元素が挙げら
れる。Examples include elements such as V, Ta, Hf, Cr, Si, Mn, B, P, Y, and rare earth elements, which have a low free energy of forming oxides, carbides, sulfides, or nitrides thereof.
次に、上記鉄系粉末に上記のＡｌ、Ｔｉ、Ｚｒ。Next, the above-mentioned Al, Ti, and Zr are added to the above-mentioned iron-based powder.
Ｖ、Ｎｂ 等の元素の粉末あるいは該元素を含む合金
粉末を添加して混合粉末とする。ここで、Ａｔ。Powders of elements such as V and Nb or alloy powders containing these elements are added to form a mixed powder. Here, At.
Ｔｉ、Ｚｒ、Ｖ、Ｎｂ 等の元素の粉末あるいは該元
素を含む合金粉末の添加量は、その好適量が焼結体中に
含まれる酸素、炭素、硫黄、窒素の量や、該元素の原子
量、さらには生成せしめる安定な化合物の構造などによ
って異なる。例えば、鉄系粉末として金属射出成形に一
般的に用いられるカルボニル鉄粉を用いた場合、上述し
た如く粉末中に約０．２重量％の酸素と約０．１重量％
の炭素を含んでいることから、真空焼結においてこれら
酸素や炭素などを十分上記元素と反応せしめるには、上
記元素として最も原子量の小さいホウ素を用いた場合で
も０．５重量％以上が必要となり、他の元素を用いた場
合では２〜ＩＯ重量％以上必要となる。また、水素中焼
結によると、酸素と炭素の一部は昇温途中にそれぞれ■
１，０、ＣＨ，の形で逃散し、空隙が孤立化した時点で
の焼結体中に残留する酸素と炭素とはそれぞれ０．０１
％、０．０３％に減少するので、必要な上記元素の添加
量としては真空焼結の場合に比べて少なくてよい。した
がって、これら安定な化合物を生成する元素の添加量と
しては、該元素の総量として０．２重量％以上添加する
のが好ましい。また、上記元素粉末を含む合金粉末を添
加し、混合粉末とする場合は、該元素の拡散距離を考慮
すると２重量％以上添加するのが望ましい。一方、上記
元素粉末をあらかじめ含む鉄系合金粉末の場合は、拡散
距離が短いため０．２重量％以上添加すればよい。The appropriate amount of powder of elements such as Ti, Zr, V, Nb, etc. or alloy powder containing these elements depends on the amount of oxygen, carbon, sulfur, and nitrogen contained in the sintered body, and the atomic weight of the elements. It also varies depending on the structure of the stable compound being produced. For example, when carbonyl iron powder, which is commonly used in metal injection molding, is used as the iron-based powder, as described above, the powder contains about 0.2% by weight of oxygen and about 0.1% by weight.
Therefore, in order for these oxygen and carbon to sufficiently react with the above elements during vacuum sintering, 0.5% by weight or more is required even when using boron, which has the smallest atomic weight as the above element. , when other elements are used, 2 to IO weight % or more is required. In addition, according to sintering in hydrogen, some of the oxygen and carbon are released during heating, respectively.
The oxygen and carbon that escape in the form of 1,0, CH, and remain in the sintered body at the time when the void becomes isolated, are each 0.01
%, to 0.03%, the required amount of the above-mentioned elements to be added may be smaller than in the case of vacuum sintering. Therefore, the amount of elements that produce these stable compounds is preferably 0.2% by weight or more as a total amount of the elements. Further, when an alloy powder containing the above-mentioned elemental powder is added to form a mixed powder, it is desirable to add 2% by weight or more in consideration of the diffusion distance of the element. On the other hand, in the case of iron-based alloy powder that already contains the above-mentioned elemental powder, it is sufficient to add 0.2% by weight or more because the diffusion distance is short.
次いで、得られた混合粉末を所望する形状に成形し、そ
の後焼結して焼結体相対密度９８％以上の鉄系焼結体を
得る。この場合に焼結温度としては、原料粉末として上
記元素をあらかじめ含む合金元素を用いる場合、１２５
０℃以上とするのが好ましく、原料粉末として混合粉末
を用いる場合、特に上記安定な化合物を生成するための
元素を焼結体内に短時間に均一に拡散させるためには、
１４００℃以上の温度で焼結するのが望ましい。Next, the obtained mixed powder is molded into a desired shape, and then sintered to obtain an iron-based sintered body having a relative density of 98% or more. In this case, the sintering temperature is 125
The temperature is preferably 0°C or higher, and when using a mixed powder as the raw material powder, in particular, in order to uniformly diffuse the elements for producing the above-mentioned stable compound into the sintered body in a short time.
It is desirable to sinter at a temperature of 1400° C. or higher.
なお、上記の焼結温度にて安定である化合物を生成する
元素の添加量が少ない場合、該元素が鉄系粉末に均一に
分散せず局在し、これにより焼結体全体に効果が及ばな
いことがあり、したがってこの場合には、焼結温度を高
くし該元素の拡散を十分に促すことが焼結体密度を高く
するうえで必要となる。In addition, if the amount of an element that produces a compound that is stable at the above sintering temperature is small, the element will not be uniformly dispersed in the iron-based powder but will be localized, and this will have an effect on the entire sintered body. Therefore, in this case, it is necessary to raise the sintering temperature to sufficiently promote the diffusion of the element in order to increase the density of the sintered body.
このようにして焼結すると、上述した焼結温度にて安定
な化合物を生成する元素は、焼結体内部の孤立する空隙
内に発生しあるいは存在する各種ガスの構成元素、すな
わち酸素、炭素、硫黄、窒素などと反応し、酸化物、炭
化物、硫化物、窒化物などの安定な化合物となる。した
がって、焼結体内部におけるＨｘＯ，ＣＯ，Ｓ、Ｎ！な
どのガスの発生が防止され、これにより焼結体内部にお
ける孤立空隙内のガスの圧力が、上記安定な化合物の蒸
気圧以下となることから焼結体内部の孤立空隙の表面応
力（空隙の収縮の駆動力）以下となり、空隙の収縮に対
して障害とならず、よって焼結体は十分に緻密化される
。When sintered in this way, the elements that form stable compounds at the above-mentioned sintering temperature are the constituent elements of various gases generated or present in isolated voids inside the sintered body, such as oxygen, carbon, Reacts with sulfur, nitrogen, etc. to form stable compounds such as oxides, carbides, sulfides, and nitrides. Therefore, HxO, CO, S, N! inside the sintered body! The generation of gases such as The driving force for contraction is less than 10%, and there is no obstacle to the contraction of the voids, so that the sintered body is sufficiently densified.
例えば、全ての酸素あるいは炭素が上記元素によって安
定化された場合、１４００℃において空隙に発生するＣ
Ｏガス圧の例を示せばそれぞれ下記のようになる。For example, if all oxygen or carbon is stabilized by the above elements, carbon generated in the voids at 1400°C
Examples of O gas pressure are as follows.
Ｔｉ１ｌ 、４ Ｘ １０−’気圧、Ｎｂ；６．９ Ｘ
１０−’気圧。Ti1l, 4 x 10-'atm, Nb; 6.9 x
10-'atm.
Ａｌ；４ Ｘ ｌ Ｏ””気圧、Ｃｒ；０．２１気圧。Al: 4×1 O”” atmosphere, Cr: 0.21 atmosphere.
Ｓ ｉ；８ Ｘ １０−’気圧、Ｖ ：８．６ Ｘ ｌ
Ｏ−’気圧Ｍｎ；２ Ｘ ｌ Ｏ″″３″３気圧
「作用 」
この発明の製造方法によれば、鉄系粉末に焼結温度にて
安定である炭化物、酸化物、硫化物、あるいは窒化物を
生成する元素の単体粉末または該元素を含む合金粉末の
一種以上を添加してなる混合粉末か、あるいは上記元素
を含有してなる鉄系合金粉末を用意し、次いで用意した
混合粉末あるいは鉄系合金粉末を成形し焼結するので、
焼結時にＨｘＯ，Ｇｏ、Ｓ、Ｎ！などのガスの発生が防
止され、これにより該ガスの圧力に起因して焼結体内部
の孤立空隙の収縮が妨げられることがなくなる。Si; 8 x 10-'atm, V: 8.6 x l
O-'atmosphere Mn; 2 A single powder of an element that produces a product or a mixed powder made by adding one or more types of alloy powder containing the element, or an iron-based alloy powder containing the above elements is prepared, and then the prepared mixed powder or iron Since the alloy powder is molded and sintered,
HxO, Go, S, N! during sintering! This prevents the generation of gases such as, and thereby prevents the contraction of isolated voids inside the sintered body from being hindered by the pressure of the gases.
「実施例」
以下、実施例によりこの発明をさらに具体的に説明する
。"Examples" The present invention will be explained in more detail below using Examples.
（実施例１）
鉄系粉末として平均粒径５μｍのカルボニル鉄粉（含有
酸素量；０．２重量％、含有炭素量；０゜１重量％、含
有硫黄量、０．０１重量％）を用い、これに３２５メツ
シユ以下のＴｉ粉末を全体の４重量％となるように添加
し、ボールミル中にて混合し混合粉末とした。(Example 1) Carbonyl iron powder (oxygen content: 0.2% by weight, carbon content: 0°1% by weight, sulfur content: 0.01% by weight) with an average particle size of 5 μm was used as the iron-based powder. , Ti powder of 325 meshes or less was added to the powder in an amount of 4% by weight of the total, and mixed in a ball mill to obtain a mixed powder.
次に、この混合粉末をＩｔ／ｃｍ”の圧力でプレス成形
し、直径２０ｍｍ、高さ１０ｍｍの円柱状の成形体を得
た。次いで、この成形体をＩ Ｏ−’Ｔｏｒｒ程度の真
空中にて１４００℃で１時間焼結した。Next, this mixed powder was press-molded at a pressure of "It/cm" to obtain a cylindrical molded body with a diameter of 20 mm and a height of 10 mm.Then, this molded body was placed in a vacuum of about I O-'Torr. and sintered at 1400°C for 1 hour.
得られた焼結体の相対密度、組織の状態を調べ、その結
果を第１表に示す。The relative density and structure of the obtained sintered body were examined, and the results are shown in Table 1.
また比較のため、上記のカルボニル鉄粉のみを用い、上
記実施例のものと同様に成形、焼結して焼結体を得、相
対密度、組織の状態を調べてその結果を第１表に示す。For comparison, using only the above carbonyl iron powder, a sintered body was obtained by molding and sintering in the same manner as in the above example, and the relative density and structure were examined. The results are shown in Table 1. show.
第１表
第１表に示した結果より、本発明品は空隙のない緻密な
焼結体となったが、比較界としてのカルボニル鉄粉を単
独で用い、成形、焼結したものでは焼結体相対密度が９
６％までにしかならず、焼結体組織に空隙の存在が認め
られた。Table 1 From the results shown in Table 1, the product of the present invention became a dense sintered body with no voids, but the product formed and sintered using carbonyl iron powder alone as a comparative example was found to be sintered. Body relative density is 9
It was only up to 6%, and the presence of voids in the structure of the sintered body was observed.
（実施例２）
実施例１と同一のカルボニル鉄粉を用い、これにＦｅ−
５１重量％Ａ１合金粉を、Ａｌｌが全体の４重量％とな
るように添加し、実施例１と同様の方法で混合、成形、
焼結した。(Example 2) Using the same carbonyl iron powder as in Example 1, Fe-
51% by weight A1 alloy powder was added so that All was 4% by weight, and mixed, molded, and molded in the same manner as in Example 1.
Sintered.
得られた焼結体の相対密度、組織の状態を調べたところ
、相対密度がほぼ１００％であり、また組織に空隙は認
められなかった。When the relative density and structure of the obtained sintered body were examined, the relative density was approximately 100%, and no voids were observed in the structure.
（実施例３）
鉄系粉末として、Ｆｅ−８％Ｎｉ水アトマイズ粉末を用
い、これにＦｅ−６６％Ｎｂ合金粉末を、Ｎｂが全体の
４重量％となるように添加し、ボールミルで混合した。(Example 3) Fe-8%Ni water atomized powder was used as the iron-based powder, and Fe-66%Nb alloy powder was added thereto so that Nb was 4% by weight of the total, and mixed in a ball mill. .
得られた混合粉にメタクリル酸エステルが主成分となる
バインダー１０重量部を加え、１４０℃で１時間混合し
て混練物とした。次に、スクリュー型の射出成形機で７
ｘ７Ｘ７０ｍｍの直方体状の成形体を得た。ここで、射
出温度は１６０℃、射出圧力１０００ ｋｇ／ ｃｍ”
とした。10 parts by weight of a binder mainly composed of methacrylic acid ester was added to the obtained mixed powder, and the mixture was mixed at 140° C. for 1 hour to obtain a kneaded product. Next, a screw-type injection molding machine is used to
A rectangular parallelepiped-shaped molded product measuring 7x70 mm was obtained. Here, the injection temperature is 160℃, and the injection pressure is 1000 kg/cm"
And so.
次いで、得られた成形体を空気中にて１０℃／Ｈｒの速
さで３２０℃まで昇温し、この温度で２時間保持した。Next, the temperature of the obtained molded body was raised to 320° C. at a rate of 10° C./Hr in air, and maintained at this temperature for 2 hours.
その後、この成形体を水素雰囲気中にて１４０℃で焼結
し、焼結体を得た。Thereafter, this molded body was sintered at 140° C. in a hydrogen atmosphere to obtain a sintered body.
得られた焼結体の相対密度、組織の状態、引っ張り強さ
、伸びを調べ、その結果を第２表に示す。The relative density, state of structure, tensile strength, and elongation of the obtained sintered body were examined, and the results are shown in Table 2.
また比較のため、鉄系粉末として上記Ｆｅ−８％Ｎｉ水
アトマイズ粉末を単独で用い、実施例と同様にして混練
、成形、焼結を行って焼結体を得、この焼結体の相対密
度、組織の状態、引っ張り強さ、伸びを調べてその結果
を第２表に示す。For comparison, the above-mentioned Fe-8%Ni water atomized powder was used alone as the iron-based powder, and kneaded, molded, and sintered in the same manner as in the example to obtain a sintered body. The density, texture, tensile strength, and elongation were examined and the results are shown in Table 2.
第２表
第２表に示した結果より、本発明品は焼結体相対密度が
ほぼ１００％となり組織に空隙も認められず緻密な焼結
体となったが、比較量のＦｅ−８％Ｎｉ水アトマイズ粉
末を単独で用い、成形、焼結したものでは焼結体相対密
度が９６％までにしかならず、焼結体組織に空隙の存在
が認められた。Table 2 From the results shown in Table 2, the relative density of the sintered compact of the present invention product was almost 100%, and no voids were observed in the structure, resulting in a dense sintered compact, but the comparative amount of Fe-8 When Ni water atomized powder was used alone, molded and sintered, the relative density of the sintered body was only up to 96%, and the presence of voids was observed in the structure of the sintered body.
また本発明品では、比較量に比べて伸び、引っ張り強さ
においても改善されていることが確認された。It was also confirmed that the product of the present invention was improved in elongation and tensile strength compared to comparative products.
（実施例４）
鉄系粉末として、１００メツシユ以下の電解鉄粉を用い
、これに３２５メツシユ以下のＴｉ粉末を全体の４重量
％となるように添加し、混合して混合粉末とした。(Example 4) Electrolytic iron powder of 100 mesh or less was used as the iron-based powder, and Ti powder of 325 mesh or less was added thereto in an amount of 4% by weight of the total and mixed to obtain a mixed powder.
次に、この混合粉末を５０ｔ／ｃｍ”の圧力でプレス成
形し、直径２０ｏ＋ｎ＋、高さｔＯｍｍの円柱状の成形
体を得た。次いで、この成形体を水素雰囲気中にて１４
００℃で１時間焼結した。Next, this mixed powder was press-molded at a pressure of 50t/cm'' to obtain a cylindrical molded body with a diameter of 20o+n+ and a height of tOmm.Then, this molded body was heated in a hydrogen atmosphere for 14 hours.
Sintering was carried out at 00°C for 1 hour.
得られた焼結体の相対密度を調べたところ、９９％であ
り、良好な緻密性を有していることが確認された。When the relative density of the obtained sintered body was examined, it was found to be 99%, confirming that it had good density.
「発明の効果」
以上説明したように、この発明の高密度鉄系焼結体の製
造方法は、
鉄系粉末に焼結温度にて安定である炭化物、酸化物、硫
化物、あるいは窒化物を生成する元素の単体粉末または
該元素を含む合金粉末の一種以上を添加してなる混合粉
末か、あるいは上記元素を含有してなる鉄系合金粉末を
用意し、次いで用意した混合粉末あるいは鉄系合金粉末
を成形し、その後焼結して焼結体相対密度９８％以上の
鉄系焼結体を得るものであるから、上記の添加した元素
が焼結時に、焼結体内部の孤立する空隙内に発生しある
いは存在する各種ガスの構成元素、すなわち酸素、炭素
、硫黄、窒素などと反応し、酸化物、炭化物、硫化物、
窒化物などの安定な化合物となるため、Ｈｉｄ、Ｃｏ、
Ｓ、Ｎｐなどのガスの発生が防止または抑制され、これ
により該ガスの圧力に起因して焼結体内部の孤立空隙の
収縮が妨げられることかなくなり、十分に緻密な焼結体
が得られるものとなる。したがって、この発明の製造方
法にあっては、従来の焼結体では使用し得なかった繰り
返し応力や衝撃がかかる箇所に用いられる部材の製造に
も十分適用することかでき、よって焼結体の用途を格段
に拡げることができる。また、１回の常温焼結によって
十分緻密な焼結体を得ることができることから、
従来の焼結体の製造に比
べて十分生産性を高めることができる。"Effects of the Invention" As explained above, the method for producing a high-density iron-based sintered body of the present invention includes adding carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature to the iron-based powder. A single powder of the element to be produced or a mixed powder obtained by adding one or more types of alloy powder containing the element, or an iron-based alloy powder containing the above elements is prepared, and then the prepared mixed powder or iron-based alloy is prepared. Since the powder is compacted and then sintered to obtain an iron-based sintered body with a relative density of 98% or more, the above-mentioned added elements are absorbed into the isolated voids inside the sintered body during sintering. Reacts with constituent elements of various gases generated or present, such as oxygen, carbon, sulfur, and nitrogen, to form oxides, carbides, sulfides,
Hid, Co,
The generation of gases such as S and Np is prevented or suppressed, so that the contraction of isolated voids inside the sintered body is not hindered due to the pressure of the gas, and a sufficiently dense sintered body can be obtained. Become something. Therefore, the manufacturing method of the present invention can be fully applied to the manufacturing of parts used in locations subject to repeated stress or impact, which could not be used with conventional sintered bodies. The range of uses can be greatly expanded. Furthermore, since a sufficiently dense sintered body can be obtained by one-time room temperature sintering, productivity can be sufficiently increased compared to the conventional production of sintered bodies.
Claims (5)
物、硫化物、あるいは窒化物を生成する元素の単体粉末
または該元素を含む合金粉末の一種以上を添加してなる
混合粉末か、あるいは上記元素を含有してなる鉄系合金
粉末を用意し、次いで用意した混合粉末あるいは鉄系合
金粉末を成形し、その後焼結して焼結体相対密度９８％
以上の鉄系焼結体を得る高密度鉄系焼結体の製造方法。(1) Mixed powder made by adding to iron-based powder one or more single powders of elements that produce carbides, oxides, sulfides, or nitrides that are stable at sintering temperatures, or one or more types of alloy powders containing these elements. Alternatively, prepare an iron-based alloy powder containing the above elements, then mold the prepared mixed powder or iron-based alloy powder, and then sinter it to obtain a sintered body with a relative density of 98%.
A method for producing a high-density iron-based sintered body to obtain the above iron-based sintered body.
において、鉄系粉末として鉄の含有量が５０〜１００重
量％である高密度鉄系焼結体の製造方法。(2) The method for producing a high-density iron-based sintered body according to claim 1, wherein the content of iron as the iron-based powder is 50 to 100% by weight.
において、焼結温度にて安定となる炭化物、酸化物、硫
化物あるいは窒化物を生成する元素が、Ａｌ、Ｔｉ、Ｚ
ｒ、Ｎｂ、Ｖ、Ｔａ、Ｈｆ、Ｃｒ、Ｓｉ、Ｍｎ、Ｂ、Ｐ
、Ｙおよび希土類元素の中から選択される高密度鉄系焼
結体の製造方法。(3) In the method for producing a high-density iron-based sintered body according to claim 1, the elements that produce carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature are Al, Ti, and Z.
r, Nb, V, Ta, Hf, Cr, Si, Mn, B, P
, Y and rare earth elements.
において、焼結温度にて安定となる炭化物、酸化物、硫
化物あるいは窒化物を生成する元素の添加量が総量で０
．２重量％以上である高密度鉄系焼結体の製造方法。(4) In the method for producing a high-density iron-based sintered body according to claim 1, the total amount of elements that produce carbides, oxides, sulfides, or nitrides that are stable at the sintering temperature is 0.
．． A method for producing a high-density iron-based sintered body having a content of 2% by weight or more.
において、焼結温度が１２５０℃以上である高密度鉄系
焼結体の製造方法。(5) The method for producing a high-density iron-based sintered body according to claim 1, wherein the sintering temperature is 1250° C. or higher.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2519289A JPH02205655A (en) | 1989-02-03 | 1989-02-03 | Manufacture of high density ferrous sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2519289A JPH02205655A (en) | 1989-02-03 | 1989-02-03 | Manufacture of high density ferrous sintered body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02205655A true JPH02205655A (en) | 1990-08-15 |
Family
ID=12159102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2519289A Pending JPH02205655A (en) | 1989-02-03 | 1989-02-03 | Manufacture of high density ferrous sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02205655A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104942278A (en) * | 2014-03-26 | 2015-09-30 | 精工爱普生株式会社 | Metal powder for powder metallurgy, compound, granulated powder, sintered body, and method for producing sintered body |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5822308A (en) * | 1981-07-30 | 1983-02-09 | Toshiba Corp | Manufacture of high-density sintered material |
| JPS61257454A (en) * | 1985-04-22 | 1986-11-14 | モエン インコーポレーテッド | High density sintered alloy |
| JPS6256543A (en) * | 1985-09-06 | 1987-03-12 | Showa Denko Kk | Manufacture of sintered compact of rare-earth alloy |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104942278A (en) * | 2014-03-26 | 2015-09-30 | 精工爱普生株式会社 | Metal powder for powder metallurgy, compound, granulated powder, sintered body, and method for producing sintered body |
| CN104942278B (en) * | 2014-03-26 | 2020-03-03 | 精工爱普生株式会社 | Metal powder for powder metallurgy, composite, granulated powder, and sintered body |
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