JPH0657365A - Isotropic powder metallurgical material and its production - Google Patents
Isotropic powder metallurgical material and its productionInfo
- Publication number
- JPH0657365A JPH0657365A JP4213985A JP21398592A JPH0657365A JP H0657365 A JPH0657365 A JP H0657365A JP 4213985 A JP4213985 A JP 4213985A JP 21398592 A JP21398592 A JP 21398592A JP H0657365 A JPH0657365 A JP H0657365A
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- JP
- Japan
- Prior art keywords
- powder
- capsule
- oxygen content
- hot
- mechanical properties
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ガスアトマイズ法によ
って製造された低酸素球状粉末をカプセル(金属製容器)
に封入後、熱間静水圧プレス(以後ＨＩＰと記す)法によ
って圧密し、さらに鍛造、圧延等の熱間塑性加工を経て
製造される粉末冶金材料およびその製造方法に関し、特
に機械的性質の異方性の小さいものに関する。FIELD OF THE INVENTION The present invention is a capsule (metal container) of low oxygen spherical powder produced by a gas atomizing method.
Powder metallurgical material manufactured by hot isostatic pressing (hereinafter referred to as HIP) method, and then hot plastic working such as forging and rolling. Regarding the one with a small tendency.
【０００２】[0002]
【従来の技術】粉末冶金法による材料は溶製材に比し、
高合金化が可能である、組織が緻密で機械的性質が優れ
ている等の特徴を有する。このうち、いわゆる粉末ハイ
スや粉末ダイス鋼等の工具材料がその中心的対象とな
る。これらは、超急冷凝固された予備合金粉末をＨＩＰ
法で塊状化することによって均一微細な金属組織を具現
し、よって高い機械的性質を取得できることを特徴とす
るものである。確かにこのプロセスによって製造された
材料は、鋼材の長手方向（Ｌ方向）の機械的性質は良好
であるが、径方向（Ｔ方向）の機械的性質は、それほど
十分でなく、Ｔ／Ｌ比率は0.6〜0.7である。通常の溶製
材でもＴ／Ｌ比率は一般にこれとほぼ同レベルである
が、溶製材の異方性は加工方向に配向した一次炭化物の
縞状偏析等がその原因とされてきた。粉末材には、この
ような組織が存在しないにもかかわらず、ほぼ同じレベ
ルの異方性が存在することは、当業界で衆知である。2. Description of the Related Art Materials produced by powder metallurgy are
It has the characteristics that it can be highly alloyed, has a dense structure, and has excellent mechanical properties. Of these, tool materials such as so-called powder high speed steel and powder die steel are the main objects. These are HIPs of pre-alloyed powders that have been rapidly quenched and solidified.
It is characterized in that a uniform fine metal structure is embodied by agglomeration by the method, and thus high mechanical properties can be obtained. Certainly, the material manufactured by this process has good mechanical properties in the longitudinal direction (L direction) of steel, but the mechanical properties in the radial direction (T direction) are not so sufficient, and the T / L ratio is Is 0.6 to 0.7. Although the T / L ratio is generally at the same level as in the case of ordinary ingots, the anisotropy of ingots has been attributed to striped segregation of primary carbides oriented in the working direction. It is well known in the art that powder materials have approximately the same level of anisotropy despite the absence of such a texture.
【０００３】[0003]
【発明が解決しようとする課題】本発明者はこの原因に
ついて種々検討した結果、原料粉末表面の酸化物が鍛
造、圧延後も完全には無害化されていないことが、この
原因であると推察するに至った。図１に等径粒子のＨＩ
Ｐままの状態、ならびにこれを熱間鍛造した後の粉末表
面の酸化物の存在状況を模式的に示した。ＨＩＰままの
状態では、球状粒子が正１２面体状に静水圧的に変形さ
れる際に、酸化被膜は一部破れるが、実質的には粉末表
面にそのまま残存している。この状態では、粉末界面は
酸化被膜を介して機械的に接合しているだけであるため
に、強度の絶対値は極めて弱く、また、機械的性質の異
方性は存在しない。As a result of various studies on the cause, the present inventor conjectured that the cause is that the oxide on the surface of the raw material powder is not completely rendered harmless after forging and rolling. Came to do. Figure 1 shows the HI
The state of P as it is and the presence of oxides on the powder surface after hot forging are schematically shown. In the state of HIP as it is, when the spherical particles are hydrostatically deformed into a regular dodecahedron, the oxide film is partially broken, but substantially remains as it is on the powder surface. In this state, since the powder interface is only mechanically bonded via the oxide film, the absolute value of strength is extremely weak, and the anisotropy of mechanical properties does not exist.
【０００４】これに鍛造、圧延等の加工を付加すると、
粉末界面で滑りが生じるために、酸化被膜が破れ、金属
−金属接合の割合が増加して機械的性質は大きく向上す
る。この時、鍛伸や圧延の方向（Ｌ）とそれに直角の方
向（Ｔ）について、酸化被膜の破れやすさが異なること
は容易に類推できる。実際の現象からいえば、鍛伸方向
に平行な粒子界面より、それに直角な粒子界面の方が金
属接触の割合が多くなり、結果的にＬ方向の機械的強度
の方が高くなるものと思われる。それぞれの方向の機械
的強度は、鍛造比の増加と共に、Ｌ，Ｔ方向とも酸化被
膜の破れが進行して接合強度が高くなり、Ｔ／Ｌ比も増
加する。鍛造比と、Ｌ，Ｔ方向の引張り強さの変化の関
係を模式的に図２に示した。鍛造比の増加とともにＴ／
Ｌ比は増加、すなわち異方性は軽減される。しかし、実
際問題として、鍛造比が十分とれないような太径材では
Ｔ方向の機械的性質は不十分なものとなり、また高鍛造
比は高コストに繋がる。本発明の目的は、従来の製造方
法での粉末冶金材料のかかる機械的性質の異方性を緩和
ないしは著しく軽減し、または低鍛造比でも高い機械的
性質を示す粉末冶金材料およびその製造方法を提供する
ことにある。When processing such as forging and rolling is added to this,
Due to slippage at the powder interface, the oxide film breaks, the proportion of metal-metal bonding increases, and the mechanical properties are greatly improved. At this time, it can be easily inferred that the easiness of tearing of the oxide film is different in the forging or rolling direction (L) and the direction (T) perpendicular thereto. From an actual phenomenon, it is considered that the ratio of metal contact is higher at the grain interface perpendicular to the grain interface parallel to the forging direction, and as a result, the mechanical strength in the L direction is higher. Be done. Regarding the mechanical strength in each direction, as the forging ratio increases, the tearing of the oxide film progresses in both the L and T directions to increase the bonding strength, and the T / L ratio also increases. The relationship between the forging ratio and the changes in the tensile strength in the L and T directions is schematically shown in FIG. T / with increasing forging ratio
The L ratio is increased, that is, the anisotropy is reduced. However, as a practical matter, a large-diameter material that does not have a sufficient forging ratio has insufficient mechanical properties in the T direction, and a high forging ratio leads to high cost. An object of the present invention is to provide a powder metallurgical material and a manufacturing method thereof which alleviate or significantly reduce the anisotropy of such mechanical properties of the powder metallurgical material in the conventional manufacturing method or show high mechanical properties even at a low forging ratio. To provide.
【０００５】[0005]
【課題を解決するための手段】Ｎ2,Ａr等の不活性ガス
によるガスアトマイズ法によって製造された粉末は、例
えば工具鋼粉末では通常少なくとも60ppmの酸素を含有
する。この酸素は、通常粉末表面に酸化物被膜の形態で
存在する。ガスアトマイズ−ＨＩＰ法では、かかる原料
粉末の酸素量を増加させないよう、一般には種々の施策
がとられる。具体的には、カプセルに粉末を充填後、粉
末表面に物理的に吸着されているガス成分を除去できる
温度(通常500℃)まで、加熱した状態で、容器内を真空
脱ガスした後、真空状態で封着し、次行程のＨＩＰ作業
を実施する。かかる方法で製造された、例えば粉末工具
材料は、通常圧密状態で100ppm以下の酸素含有量となる
が、原料粉末の酸素量よりも低い酸素含有量とすること
はできない。The powder produced by the gas atomizing method using an inert gas such as N 2 or Ar usually contains at least 60 ppm of oxygen in tool steel powder. This oxygen is usually present on the powder surface in the form of an oxide film. In the gas atomization-HIP method, various measures are generally taken so as not to increase the amount of oxygen in the raw material powder. Specifically, after filling the capsule with powder, heated to a temperature (normally 500 ° C.) at which the gas components physically adsorbed on the powder surface can be removed, the container is vacuum degassed, and then vacuumed. Seal in the state and carry out the HIP work of the next process. For example, a powder tool material produced by such a method usually has an oxygen content of 100 ppm or less in a consolidated state, but the oxygen content cannot be lower than the oxygen content of the raw material powder.
【０００６】本発明は、原料粉末中の炭素もしくは付加
的に添加された炭素粉末またはＣＯガスで粉末表面酸化
物を積極的に還元して、ＨＩＰ処理以前に粉末の表面酸
化物を除去低減することで、材料の機械的性質の異方性
を減少させることができること、特に酸素量を40ppm以
下に低減することにより、抗折力のＴ／Ｌ比を0.8以上
とし得ること、そしてこの酸素量の低減処理は、唯一粉
末をカプセルに封入した後に行なう実現し得ることを見
出したことによるものである。すなわち、本発明の第１
発明は、酸素含有量が40ppmであり、熱間加工方向に平
行(Ｌ)と直角(Ｔ)方向それぞれの抗折力のＴ／Ｌの比が
0.8以上である鉄基の等方性粉末冶金材料、このうち、
特に材料は工具鋼とするものである。また、本発明の第
２発明は、原料粉末を密閉カプセル内に充填して、熱間
静水圧プレス法で圧密して実密体とし、その後これに熱
間加工を施す粉末冶金材料の製造方法において、酸素含
有量が重量比で100ppm以下の低酸素の鉄基合金粉末であ
る原料粉末を前記カプセル内に充填後、ＣＯガス反応に
よって該粉末の表面酸化物を還元して該粉末の酸素含有
量を40ppm以下として、前記熱間加工方向に平行と直角
の方向の機械的性質の異方性を減少させることを特徴と
する等方性粉末冶金材料の製造方法である。The present invention positively reduces the powder surface oxide with carbon in the raw material powder or carbon powder additionally added or CO gas to remove and reduce the surface oxide of the powder before HIP treatment. By doing so, the anisotropy of the mechanical properties of the material can be reduced, and in particular, by reducing the oxygen content to 40 ppm or less, the T / L ratio of transverse rupture strength can be 0.8 or more, and this oxygen content It is because the inventors have found that the reduction treatment can be realized only after the powder is encapsulated. That is, the first aspect of the present invention
The invention has an oxygen content of 40 ppm, and has a T / L ratio of transverse rupture strength in the directions parallel (L) and right angles (T) to the hot working direction.
Iron-based isotropic powder metallurgical material of 0.8 or more, of which,
In particular, the material is tool steel. A second invention of the present invention is a method for producing a powder metallurgical material, which comprises filling raw material powder into a closed capsule, consolidating it by a hot isostatic pressing method into a solid body, and then subjecting this to hot working. In, the oxygen content of the powder is 100 ppm or less in weight ratio, after filling the raw powder which is a low oxygen iron-based alloy powder into the capsule, the surface oxide of the powder is reduced by CO gas reaction. The method for producing an isotropic powder metallurgical material is characterized in that the amount is 40 ppm or less and the anisotropy of mechanical properties in a direction parallel to and perpendicular to the hot working direction is reduced.
【０００７】[0007]
【作用】原料粉末の粉末表面酸化物を還元する手法とし
て、原料粉末中の炭素または添加炭素を、要すれば、真
空排気を併用して行なうことは特に新規ではない。酸素
含有量が高い水アトマイズ粉末の焼結方法としては、常
套手段でさえある。しかし、本発明のように酸素含有量
が100ppm以下等の低炭素または極低酸素粉末の表面酸化
物の除去手段として、試みられたことはないし、さらに
はその目的が圧密後鍛造等の塑性加工を施された実密体
の機械的性質の異方性の緩和、または軽減策として試み
られた事例はない。本発明材は、抗折力のＴ／Ｌ比を0.
8以上としたが、これは従来材のそれ(0.6〜0.7)に対
し、明瞭に差別化するためであり、また、後述の実施例
からもわかるように、本発明の方法により、比較的容易
に得られる範囲であるからである。また、本発明材のＯ
2含有量を40ppm以下としたのは、上記抗折力のＴ／Ｌ比
0.8以上を満足するため、また生産技術的に容易に達成
可能であるからである。Operation As a method for reducing the powder surface oxide of the raw material powder, it is not particularly novel to carry out carbon in the raw material powder or added carbon, if necessary, in combination with vacuum exhaust. As a method for sintering a water atomized powder having a high oxygen content, there is even a conventional method. However, as in the present invention, the oxygen content has not been attempted as a means for removing surface oxides of low carbon or extremely low oxygen powder such as 100 ppm or less, and the purpose thereof is plastic working such as forging after consolidation. There has been no attempt to alleviate or reduce the anisotropy of the mechanical properties of a solid body subjected to aging. The material of the present invention has a bending strength T / L ratio of 0.
Although it is 8 or more, this is for clearly differentiating from that of the conventional material (0.6 to 0.7), and as will be understood from the examples described later, the method of the present invention makes it relatively easy. This is because the range is obtained. Further, the O of the material of the present invention
2 The content of 40ppm or less means that the above-mentioned transverse rupture strength T / L ratio
This is because it can satisfy 0.8 or more and can be easily achieved in terms of production technology.
【０００８】本発明のもう一つの特徴は、かかる還元反
応を、後続工程であるＨＩＰで使用するカプセル内に粉
末が充填された状態で実施することにより、下記のよう
にハンドリングの困難性と再酸化の危険から、実質的に
唯一可能であり、好ましくはこれをＨＩＰ炉中の昇温状
態で行なって、脱ガス用の排気パイプを封じ、続いて昇
圧操作を行なうことで、より効果的に上記還元効果を発
揮させることである。金属粉末の炭素による還元反応
は、真空度と温度によって異なるが、工業的に到達でき
る真空度、すなわち10マイナス2乗Torrの近辺では、700
〜900℃以上の温度で生ずる。このような温度領域で
は、還元反応と並行して、軽度の焼結反応が生じ、粉末
の凝集が起こるために、カプセル容器外でかかる操作を
行なっても、粉末のハンドリング、例えば搬送、充填が
不可能となり、実際には実施が困難である。Another feature of the present invention is that the reduction reaction is carried out in a state where the powder used is filled in the capsule used in the subsequent step, HIP, which makes handling difficult and reproducible as follows. From the danger of oxidation, this is practically the only possibility, and it is more effective to do this at elevated temperature in the HIP furnace to seal the exhaust pipe for degassing and then to perform the boosting operation. It is to exert the above-mentioned reduction effect. The reduction reaction of carbon of metal powder depends on the degree of vacuum and temperature, but it is 700 at a degree of vacuum that can be industrially reached, that is, around 10 −2 Torr.
Occurs at temperatures above ~ 900 ° C. In such a temperature range, a slight sintering reaction occurs in parallel with the reduction reaction, and powder agglomeration occurs. Therefore, even if such an operation is performed outside the capsule container, the powder handling, for example, transportation and filling is not performed. It is impossible and actually difficult to implement.
【０００９】上記の還元反応をＨＩＰ装置内で実行でき
れば処理作業上好都合である。金属粉末を充填したカプ
セルの排気パイプを封着せずに、ＨＩＰ炉内での昇温中
に継続して、真空排気を続行し、圧密化に十分な温度に
到達して初めて、炉内でパイプを封着または排気回路を
閉鎖し、昇圧することによって工業的手法として高温還
元が可能なることが判明した。カプセル内の昇温を促進
する手法として、カプセルへの排気回路を利用して、非
酸化性ガスをカプセル内に導入し、ガスの熱伝導を利用
して、昇温を迅速化し、その後に引き続いて排気するこ
とが可能となる。この際、使用するガスとしては、
Ｈ2，Ｎ2，Ａr等が可能であるが、鋼中に固溶するＮ2ガ
ス等が好ましい。It is convenient in terms of processing work if the above reduction reaction can be executed in the HIP device. Without encapsulating the exhaust pipe of the capsule filled with metal powder, continue the vacuum evacuation during the temperature rise in the HIP furnace, and only after reaching a temperature sufficient for consolidation, the pipe in the furnace is reached. It was found that high-temperature reduction can be performed as an industrial method by sealing or closing the exhaust circuit and increasing the pressure. As a method to accelerate the temperature rise in the capsule, an exhaust circuit to the capsule is used to introduce a non-oxidizing gas into the capsule, and the heat conduction of the gas is used to accelerate the temperature rise, followed by the subsequent steps. It becomes possible to exhaust it. At this time, the gas used is
H 2, N 2, but Ar, etc. can be, N 2 gas or the like which forms a solid solution in the steel is preferable.
【００１０】本発明の方法を採用することによって、Ｈ
ＩＰ後の鋼中酸素含有量は、40ppm以下まで低減可能で
あり、その結果として、（１）ＨＩＰままの状態の機械
的性質が向上すること、（２）小さい鍛造比で材料の機
械的性質が上昇すること、（３）（２）の過程で長手方
向と径方向の機械的性質の異方性が著しく減少するこ
と、（４）副次的効果として太径材の製造が可能とな
る、等の効果を享受できる。By adopting the method of the present invention, H
The oxygen content in steel after IP can be reduced to 40ppm or less, and as a result, (1) the mechanical properties of HIP as it is improved, (2) the mechanical properties of the material with a small forging ratio. Is increased, (3) the anisotropy of mechanical properties in the longitudinal direction and the radial direction is significantly reduced in the process of (2), and (4) as a secondary effect, it is possible to manufacture a large-diameter material. , Etc. can be enjoyed.
【００１１】[0011]
【実施例】以下に実施例について説明する。 （実施例１）重量比でＣ 1.31%、Ｃr 4.22%、Ｗ 6.25
%、Ｍo 5.13%、Ｖ 3.12%、Ｃo 8.22%、残部鉄および不
可避的不純物からなる溶湯からＮ2ガスアトマイズ法に
より、-30meshの球状ハイス粉末を作成した。アトマイ
ズままの粉末の酸素含有量は、89ppm、Ｎ2含有量は340p
pmであった。この粉末を外径 100mmφ、内径 94mmφ、
高さ 100mmLの軟鋼製カプセルに充填密度 71%で充填し
た。該カプセルに外径 14mmφ、内径 10mmφの脱気パイ
プを溶接後、脱気は行なわずに、そのままＨＩＰ炉内に
装入し、ＨＩＰ装置に付属の排気用パイプと接続した。
常温で、カプセル内を10マイナス2乗Torrに排気後、約3
00℃/Hrの昇温速度で昇温を行なった。約700℃からカプ
セル内の真空度が急激に低下し、Ｃによる粉末表面酸化
物の還元反応が開始した。1100℃で真空度が10マイナス
1.5乗Torr以上に上昇するまで保持した後、ＨＩＰ炉内
を1000atm/Hrの速度で1000atmまで昇圧し1時間保持し
た。ＨＩＰ終了後のカプセルは外径 89.6mmであった。
ＨＩＰ後の材料のガス含有量は、本発明材は酸素 32pp
m、窒素 320ppmであり、後述の比較材は酸素 94ppm、Ｎ
2は335ppmであった。EXAMPLES Examples will be described below. (Example 1) C 1.31%, Cr 4.22%, W 6.25 by weight
%, Mo 5.13%, V 3.12%, Co 8.22%, the balance iron and inevitable impurities were used to form a -30 mesh spherical high-speed powder by the N 2 gas atomizing method. Oxygen content of as-atomized powder is 89ppm, N 2 content is 340p
It was pm. This powder has an outer diameter of 100 mmφ, an inner diameter of 94 mmφ,
It was filled into a 100 mm high mild steel capsule with a packing density of 71%. After welding a degassing pipe having an outer diameter of 14 mmφ and an inner diameter of 10 mmφ to the capsule, the capsule was directly placed in the HIP furnace without being degassed, and was connected to an exhaust pipe attached to the HIP device.
Approximately 3 after evacuation of the capsule to 10-square torr at room temperature
The temperature was raised at a heating rate of 00 ° C / Hr. From about 700 ° C., the degree of vacuum inside the capsule dropped sharply, and the reduction reaction of the powder surface oxide with C started. Vacuum degree is minus 10 at 1100 ℃
After the pressure was maintained at 1.5 torr or more, the pressure inside the HIP furnace was increased to 1000 atm at a rate of 1000 atm / Hr and the pressure was maintained for 1 hour. The outer diameter of the capsule after HIP was 89.6 mm.
The gas content of the material after HIP is 32 pp of oxygen for the material of the present invention.
m, nitrogen 320ppm, the comparative material described later oxygen 94ppm, N
2 was 335 ppm.
【００１２】前記により得られた焼結体をカプセルとと
もに1050〜1100℃の温度領域で鍛造比(Ｆ．Ｒ） 2,4,8,
16,32で鍛造した。鍛造後、長手、径両方向(鍛造比32か
らは長手方向のみ)をそれぞれ長さ方向とするごとく、3
mmφ×20mmLの抗折ならびに縮小したシャルピー衝撃試
験片を削出した。なお、比較材として、同一粉末を同一
カプセルに充填後、通常の脱気法、すなわち、常温で10
マイナス2乗Torrに脱気後500℃まで昇温し、さらに10マ
イナス2乗Torrに脱気して同圧力で封着した後、ＨＩＰ
炉内に装入してＨＩＰ処理を行なった。ＨＩＰパターン
は昇温、昇圧同時進行型とし、１時間で1100℃、1000at
mに昇温昇圧し、1時間保持後、降温降圧した。Forging ratio (FR) 2,4,8, in the temperature range of 1050-1100 ° C. of the sintered body obtained as described above together with capsules
Forged with 16,32. After forging, the longitudinal direction and the radial direction (from the forging ratio 32, only the longitudinal direction) is the longitudinal direction.
mmφ × 20mmL bending and reduced Charpy impact test pieces were cut out. As a comparative material, after filling the same capsule with the same powder, a conventional degassing method, that is, 10
After degassing to minus square Torr and raising the temperature to 500 ° C, degassing to 10 minus square Torr and sealing with the same pressure, then HIP
It was charged into the furnace and subjected to HIP treatment. HIP pattern is a simultaneous heating and boosting type, 1100 ° C for 1 hour, 1000at
The temperature was raised to m, the pressure was held for 1 hour, and then the temperature was lowered.
【００１３】[0013]
【表１】 [Table 1]
【００１４】本発明材と比較材の機械的性質の測定結果
を表１に示す。該表から発明材は比較材対比で、ＨＩＰ
ままの状態でも機械的性質が向上していることがわか
る。また、本発明材は鍛造比２でも長手方向 抗折力 40
0kg/mm2以上、シャルピー衝撃値 1.8kgm/cm2の高靭性を
有すること、シャルピー衝撃値のＴ／Ｌ比による異方性
も鍛造比 4で0.86と高い等方性を示すことが明らかであ
る。なお、表１の試験片の熱処理条件は、本材質の標準
的熱処理条件である1200℃焼入れ、570℃で1Hr×3回の
焼もどしである。Table 1 shows the measurement results of the mechanical properties of the material of the present invention and the comparative material. From the table, the invention material is HIP compared with the comparison material.
It can be seen that the mechanical properties are improved even as it is. Further, the material of the present invention has a longitudinal bending strength of 40 even at a forging ratio of 2.
It is clear that it has a high toughness of 0 kg / mm 2 or more and a Charpy impact value of 1.8 kgm / cm 2 , and that the anisotropy of the Charpy impact value due to the T / L ratio shows a high isotropy of 0.86 at a forging ratio of 4. is there. The heat treatment conditions for the test pieces in Table 1 are standard heat treatment conditions of this material: 1200 ° C. quenching, 570 ° C., 1 hr × 3 times tempering.
【００１５】（実施例２）重量比でＣ 2.30%、Ｃr 13.2
%、Ｍo 1.21%、Ｖ 5.1%、残部鉄および不可避的不純物
からなるＮ2ガスによる-30meshの球形状ガスアトマイズ
粉末を作成した。酸素含有量は、96ppm、Ｎ2含有量は46
0ppmであった。この粉末にグラファイト粉末を重量比で
0.1%添加し、Ｖ型ブレンダーで混合した。これを実施例
１と同じカプセルに充填後、常温で10マイナス2乗Torr
に脱気後、引き続いて純度 99.99%のＮ2ガスを導入後、
1100℃まで加熱した。その後、脱気を開始し、真空度が
10マイナス1.5乗Torrに到達した後、脱気パイプを封着
した。このカプセルをＨＩＰ炉に挿入後、1100℃×1000
atm×2hrのＨＩＰパターンで圧密した。(Example 2) C 2.30% by weight and Cr 13.2 by weight ratio
%, Mo 1.21%, V 5.1%, the balance of iron and unavoidable impurities, and a spherical gas atomized powder of -30 mesh with N 2 gas was prepared. Oxygen content is 96ppm, N 2 content is 46
It was 0 ppm. Graphite powder in weight ratio to this powder
0.1% was added and mixed with a V-type blender. After filling this into the same capsule as in Example 1, at room temperature 10 −2 Torr
After degassing, and then introducing N 2 gas with a purity of 99.99%,
Heated to 1100 ° C. After that, degassing is started and the degree of vacuum is
After reaching 10 minus 1.5 torr, the deaeration pipe was sealed. After inserting this capsule into the HIP furnace, 1100 ℃ × 1000
It was consolidated with a HIP pattern of atm × 2 hr.
【００１６】上記により得た焼結体をカプセルごと実施
例１と同じように鍛造加工（鍛造比R.F=2,4,8,16)と
し、従来材と機械的性質(抗折力)の比較を実施した。こ
の結果を表２に示す。ここで比較材は、同一粉末にグラ
ファイト粉末を添加することなく、同様のカプセルに充
填し、常温で10マイナス2乗Torrまで脱気後500℃まで昇
温して吸着ガスを除去後、10マイナス2乗Torrで封着
し、同一ＨＩＰ条件（1100℃×1000atm×2hr)で圧密し
た材料である。本発明材の酸素量は34ppm、Ｎ2量は380p
pmであった。一方、比較材の酸素量は103ppm、窒素量は
450ppmであった。実施例１の場合と同様、本合金の場合
も低い鍛造比から高い機械的性質を示し、かつ異方性が
少ない。The sintered body obtained as described above, together with the capsule, was subjected to forging (forging ratio RF = 2,4,8,16) in the same manner as in Example 1, and comparison of mechanical properties (breaking strength) with conventional materials. Was carried out. The results are shown in Table 2. Here, the comparative material was filled in the same capsule without adding graphite powder to the same powder, degassed to 10 −2 Torr at room temperature and then heated to 500 ° C. to remove the adsorbed gas, then 10 −min It is a material that has been sealed with squared Torr and consolidated under the same HIP conditions (1100 ° C. × 1000 atm × 2 hr). The oxygen content of the material of the present invention is 34 ppm, and the N 2 content is 380 p.
It was pm. On the other hand, the comparative material has an oxygen content of 103 ppm and a nitrogen content of
It was 450 ppm. Similar to the case of Example 1, this alloy also exhibits high mechanical properties from a low forging ratio and has little anisotropy.
【００１７】[0017]
【表２】 [Table 2]
【００１８】[0018]
【発明の効果】以上に説明の如く、酸素含有量が100ppm
以下の低酸素粉末の場合も、Ｃ等による還元反応を利用
することにより、Ｏ2含有量を40ppm以下に低減すること
ができ、これにより低い鍛造比でも機械的性質が高値を
示し、かつ、Ｔ／Ｌ比が0.8以上と異方性を著しく減少
することができる。以上では本発明を工具鋼を主として
述べたが、本発明は必ずしも工具鋼に限定されるもので
はないことは本発明の主旨より明らかであろう。また、
還元反応をＨＩＰ炉内、炉外でいずれで行なうかも、必
ずしもその効果を限定するものではない。脱気が炉中で
可能なＨＩＰ設備では、前者が不可能な場合は、後者を
選択すれば良い。As described above, the oxygen content is 100 ppm.
Also in the case of the following low oxygen powders, the O 2 content can be reduced to 40 ppm or less by utilizing the reduction reaction by C etc., whereby the mechanical properties show a high value even at a low forging ratio, and When the T / L ratio is 0.8 or more, the anisotropy can be significantly reduced. Although the present invention has been described above mainly with respect to tool steel, it will be apparent from the gist of the present invention that the present invention is not necessarily limited to tool steel. Also,
Whether the reduction reaction is performed inside the HIP furnace or outside the HIP furnace does not necessarily limit the effect. If the former is not possible with HIP equipment that allows degassing in a furnace, the latter can be selected.
【図１】ＨＩＰまま（ａ）およびこれに塑性加工を加え
た後（ｂ）の原料粉末粒子の表面の酸化物の存在状況を
模式的に示した図である。FIG. 1 is a diagram schematically showing the existence state of oxides on the surface of raw material powder particles after HIP as it is (a) and after it is subjected to plastic working (b).
【図２】ＨＩＰままの材料に塑性加工を加えた場合の鍛
造比（Ｆ．Ｒ）とＴ，Ｌ方向それぞれの引張強さおよび
そのＴ／Ｌの比の変化を説明する模式図である。FIG. 2 is a schematic diagram for explaining changes in forging ratio (FR), tensile strength in each of T and L directions, and its T / L ratio when plastic working is applied to a material as HIP.
───────────────────────────────────────────────────── 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 38/00 ３０４ 38/30 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Office reference number FI technical display location C22C 38/00 304 38/30
Claims (4)
向に平行(Ｌ)と直角(Ｔ)方向それぞれの抗折力のＴ／Ｌ
の比が0.8以上である鉄基の等方性粉末冶金材料。1. The oxygen content is 40 ppm, and the transverse rupture strength T / L of each of the directions parallel (L) and right angles (T) to the hot working direction.
Iron-based isotropic powder metallurgy material with a ratio of 0.8 or more.
粉末冶金材料。2. The isotropic powder metallurgy material according to claim 1, wherein the material is tool steel.
熱間静水圧プレス法で圧密して実密体とし、その後これ
に熱間加工を施す粉末冶金材料の製造方法において、酸
素含有量が重量比で100ppm以下の低酸素の鉄基合金粉末
である原料粉末を前記カプセル内に充填後、ＣＯガス反
応によって該粉末の表面酸化物を還元して該粉末の酸素
含有量を40ppm以下として、前記熱間加工方向に平行と
直角の方向の機械的性質の異方性を減少させることを特
徴とする等方性粉末冶金材料の製造方法。3. Filling the raw material powder into a closed capsule,
In the method of manufacturing a powder metallurgical material, which is compacted by a hot isostatic pressing method into a solid body, and then hot-worked, the oxygen content is a low oxygen iron-based alloy powder with a weight ratio of 100 ppm or less. After filling the raw material powder into the capsule, the surface oxide of the powder is reduced by a CO gas reaction to reduce the oxygen content of the powder to 40 ppm or less, and the mechanical properties in the direction perpendicular to the hot working direction. A method for producing an isotropic powder metallurgical material, characterized in that the anisotropy of the metal is reduced.
ＨＩＰ炉内に装入して、700℃以上で排気しつつ還元反
応を行ない、排気回路を封着後そのまま昇圧し、ＨＩＰ
処理を行なうことを特徴とする請求項３の等方性粉末冶
金材料の製造方法。4. A raw material powder is filled in a closed capsule,
It is charged into the HIP furnace, and the reduction reaction is performed while exhausting at 700 ° C or higher, and the exhaust circuit is sealed and the pressure is increased as it is.
The method for producing an isotropic powder metallurgical material according to claim 3, wherein a treatment is performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4213985A JPH0657365A (en) | 1992-08-11 | 1992-08-11 | Isotropic powder metallurgical material and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4213985A JPH0657365A (en) | 1992-08-11 | 1992-08-11 | Isotropic powder metallurgical material and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0657365A true JPH0657365A (en) | 1994-03-01 |
Family
ID=16648343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4213985A Pending JPH0657365A (en) | 1992-08-11 | 1992-08-11 | Isotropic powder metallurgical material and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0657365A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007281017A (en) * | 2006-04-03 | 2007-10-25 | Jeol Ltd | Soft magnetic material and method of manufacturing the same |
-
1992
- 1992-08-11 JP JP4213985A patent/JPH0657365A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007281017A (en) * | 2006-04-03 | 2007-10-25 | Jeol Ltd | Soft magnetic material and method of manufacturing the same |
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