JPS6245295B2 - - Google Patents
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- Publication number
- JPS6245295B2 JPS6245295B2 JP58147571A JP14757183A JPS6245295B2 JP S6245295 B2 JPS6245295 B2 JP S6245295B2 JP 58147571 A JP58147571 A JP 58147571A JP 14757183 A JP14757183 A JP 14757183A JP S6245295 B2 JPS6245295 B2 JP S6245295B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- particles
- cemented carbide
- based cemented
- compound
- 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.)
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- 239000000843 powder Substances 0.000 claims description 104
- 239000002245 particle Substances 0.000 claims description 58
- 150000001875 compounds Chemical class 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 20
- 238000005245 sintering Methods 0.000 claims description 13
- 239000011812 mixed powder Substances 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims description 9
- 150000004767 nitrides Chemical class 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 150000001247 metal acetylides Chemical class 0.000 claims description 4
- 238000004663 powder metallurgy Methods 0.000 claims description 4
- 230000000737 periodic effect Effects 0.000 claims description 2
- 239000006104 solid solution Substances 0.000 claims description 2
- 229910052723 transition metal Inorganic materials 0.000 claims description 2
- 150000003624 transition metals Chemical class 0.000 claims description 2
- 239000000203 mixture Substances 0.000 description 10
- 239000011148 porous material Substances 0.000 description 10
- 239000002994 raw material Substances 0.000 description 9
- 238000007796 conventional method Methods 0.000 description 8
- 239000006229 carbon black Substances 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052758 niobium Inorganic materials 0.000 description 4
- 229910052715 tantalum Inorganic materials 0.000 description 4
- -1 C 4 compound Chemical class 0.000 description 3
- 229910020515 Co—W Inorganic materials 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000007580 dry-mixing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- LBFUKZWYPLNNJC-UHFFFAOYSA-N cobalt(ii,iii) oxide Chemical compound [Co]=O.O=[Co]O[Co]=O LBFUKZWYPLNNJC-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Description
この発明は、分散相を形成する炭化タングステ
ン（以下WCで示す）粒子の平均粒径が約0.8μｍ
以下の微粒にして、かつ高強度および高靭性を有
するWC基超硬合金の製造法に関するものであ
る。
一般に、分散相を形成するWC粒子を主成分と
し、これを結合相形成成分であるCoで結合した
ものからなるWC基超硬合金、あるいは、さら
に、これに分散相形成成分として周期律表の４
ａ，５ａおよび６ａ族の遷移金属の炭化物および
窒化物、並びにこれらの２種以上の固溶体（以下
これらを総称して金属の炭・窒化物という）のう
ちの１種または２種以上を、通常0.1〜20％（重
量％、以下同じ）の割合で含有させたWC基超硬
合金が、切削工具や耐摩耗工具、さらに耐衝撃工
具などとして用いられ、工業上重要な役割を果し
ている。これらのWC基超硬合金のうち、特に
WC粒子の平均粒径が１μｍ以下の微粒のもの
は、エンドミル、ドリル、スリツターナイフなど
の切削速度が比較的低い領域の切削工具や冷間耐
摩耗工具などとして用いた場合にすぐれた性能を
発揮するが、近年の生産性向上の要求から、より
微粒にして、より高強度および高靭性を有する
WC基超硬合金が求められる傾向にある。
さらに、この種のWC粒子が微粒のWC基超硬
合金は、通常、原料粉末として、微細なWC粉末
とCo粉末からなる混合粉末、あるいは、これに
さらに粒成長抑制効果のある金属の炭・窒化物の
うちの１種または２種以上の粉末を配合した混合
粉末を用いて、粉末冶金法にて焼結することによ
つて製造されている。しかし、市販のWC粉末に
は最も微細なもので、０・５μｍ程度の平均粒径
を有するものがあるが、このWC粉末は酸化し易
いので取扱が難しくなるばかりでなく、品質的安
定性にも疑問があり、さらに微細なWC粉末を用
いた場合、焼結体中に巣が生じ易く、これによつ
て強度が低下するようになるという問題もある。
また、この種のWC基超硬合金においては、分散
相と結合相との界面における耐クラツク伝播性は
比較的高いが、分散相同志の界面における耐クラ
ツク伝播性は低く、したがつて、例えば切削工具
として用いると、切削速度が遅いので被削材が溶
着し、これがはがれる時に分散相同志の界面から
破壊が生じるようになるという靭性低下の問題が
ある。
そこで、本発明者等は、上述のような観点か
ら、WC粒子が微粒にして、高強度および高靭性
を有するWC基超硬合金を得べく研究を行なつた
結果、従来方法、すなわち原料粉末としてWC粉
末を使用する限り、粒成長抑制効果を有する金属
の炭・窒化物粉末を配合しても、得られるWC基
超硬合金におけるWC粒子の平均粒径は約0.8μｍ
が限度であつて、これより微粒にすることができ
ず、また同じく原料粉末としてCo粉末を使用す
る限り、これには延性があるので混合時に完全に
粉砕することができず、粗いCo粒子として残留
して焼結体中の巣発生の原因となり、さらにWC
粉末とCo粉末の混合時にWC粉末同志の接触を避
けることは不可能であることから、焼結体におけ
る界面破壊を完全に防止することができないもの
であるが、原料粉末としてCo3W、Co7W6などの
Co―Ｗ系化合物や、Co3W3C、Co6W6C、
Co2W4C、Co3W9C4などのCo―Ｗ―Ｃ系化合物の
粉末を使用すると、これらの化合物粉末は金属間
化合物特有の脆い特性をもつので、容易に微粉砕
することができ、さらにこれに炭素粉末を混合
し、圧粉体とした状態で焼結すると、これらの化
合物は容易に分解してWCとCoを形成するので、
焼結条件を調整して、WCの形成後粒成長しない
ようにすれば、WC粒子が、平均粒径で約0.8μｍ
以下のきわめて微粒の組織をもつばかりでなく、
WC粒子同志の接着も著しく少なく、かつ結合相
がWC粒子と同様に析出Coによつて形成されてい
るので、巣発生の原因となる粗大Co粒子がほと
んど存在しないWC基超硬合金が得られ、この結
果のWC基超硬合金は高強度と高靭性をもつとい
う知見を得たのである。
この発明は、上記知見にもとづいてなされたも
のであつて、粉末冶金法によりWC基超硬合金を
製造するに際して、原料粉末として、Co―Ｗ系
化合物粉末およびCo―Ｗ―Ｃ系化合物粉末のう
ちの１種または２種以上に、焼結中の脱炭および
浸炭量を加味し、これらの化合物中のＷと結合し
てWCを生成するのに必要な量の炭素粉末を配合
してなる混合粉末、あるいは、これにさらにWC
粒子の粒成長抑制、並びに合金の耐摩耗性、耐熱
性、および耐食性の向上をはかる目的で、金属の
炭・窒化物のうちの１種または２種以上の粉末
を、望ましくは0.1〜20％配合してなる混合粉末
を使用し、この混合粉末を圧粉体とした状態で、
望ましくは1350℃以下の温度で焼結し、この焼結
時に前記化合物を分解させてWCとCoとを生成せ
しめることによつて、WC粒子の平均粒径が約0.8
μｍ以下の微粒にして、高強度および高靭性を有
するWC基超硬合金を製造することに特徴を有す
るものである。
なお、この発明の方法において用いられるCo
―Ｗ系化合物粉末およびCo―Ｗ―Ｃ系化合物粉
末は例えばCo粉末とＷ粉末、あるいはCo粉末
と、Ｗ粉末と、WCおよびW2Cなどの炭素源粉
末、さらにあるいは酸化コバルト粉末と酸化タン
グステン粉末と炭素粉末をそれぞれ所定の組成に
配合し、非酸化性雰囲気中、800〜1300℃の範囲
内の所定の温度に加熱することによつて製造する
ことができ、また、製造されるWC基超硬合金の
組成は、それぞれ原料粉末として、例えばCo3W
粉末を用いれば、焼結後の合金中のCo含有量は
47％となり、同様にCo3W3Cでは23％、Co2W4C
では13％、Co3W9C4では９％となるので、これら
原料粉末を適当に組合せることによつて所定の組
成とすることができる。さらに焼結後のWC基超
硬合金に熱間静水圧処理を施して、残留している
わずかの巣などを除去してやれば、より一層の特
性向上がはかれる。
つぎに、この発明の方法を実施例により具体的
に説明する。
実施例 １
Co―Ｗ系化合物を調製する目的で、平均粒
径：1.3μｍのCo粉末と、同1.0μｍのＷ粉末を用
意し、これら粉末を、Co粉末：27％、Ｗ粉末：
73％の割合に配合し、乾式混合した後、１気圧の
水素気流中、温度：900℃に３時間保持すること
によつてCo―Ｗ系化合物粉末を製造した。この
Co―Ｗ系化合物粉末は、Ｘ線回折によりCo7W6
の単一組成をもつことが判明した。ついで、この
Co―Ｗ系化合物粉末に、4.6％のカーボンブラツ
クを配合し、ボールミルにて24時間湿式混合して
混合粉末とし、乾燥した後、圧粉体にプレス成形
し、この圧粉体を、真空中、温度：1280℃に２時
間の条件で焼結することによつて本発明法１を実
施した。この本発明法１により得られたWC基超
硬合金は、Co：26％を含有し、WCとCoがきれ
いに分散した組織を有し、かつWC粒子の平均粒
径は0.3μｍときわめて微細であり、異常成長し
たWC粒子やポアは全く観察されなかつた。
一方、比較の目的で、原料粉末として、平均粒
径：0.55μｍを有するWC粉末をボールミルにて
粉砕して同0.2μｍとしたWC粉末と、同1.3μｍ
のCo粉末を使用する以外は、上記の本発明法１
と同一の条件で従来法１を行なつた。この従来法
１により製造されたWC基超硬合金は、WC粒子
が平均粒径：0.8μｍを示すものの、数μｍにま
で異常成長したWC粒子が散在し、WC粒子の分
散も悪く、しかもその研摩面上にはポアが認めら
れるものであつた。
なお、本発明法１により製造されたWC基超硬
合金は、480Kg／mm2のきわめて高い抵抗力を示す
のに対して、従来法１により製造されたものは
300Kg／mm2の低い抵抗力しか示さなかつた。
実施例 ２
まず、Co―Ｗ―Ｃ系化合物粉末を製造する目
的で、実施例１で用いたと同じCo粉末およびＷ
粉末のほかに、未粉砕のWC粉末を用い、これら
粉末を、Co粉末：14％、Ｗ粉末：64％、WC粉
末：22％の割合に配合し、乾式混合した後、真空
中、温度：1000℃に２時間保持の条件で加熱し
て、Ｘ線回折で組成式：Co2W4Cを示す化合物を
主成分とするCo―Ｗ―Ｃ系化合物粉末を製造し
た。
ついで、このCo―Ｗ―Ｃ系化合物粉末に、4.1
％のカーボンブラツクを配合し、ボールミルにて
48時間湿式混合し、乾燥して混合粉末とし、この
混合粉末より成形した圧粉体を、真空中、温度：
1290℃に１時間保持の条件で焼結することによる
本発明法２を実施した。この本発明法２により製
造されたWC基超硬合金は、Co：13％を含有し、
かつWCとCoがきれいに分散した組織を有し、し
かもWC粒子の平均粒径が0.2μｍの微粒であつ
て、異常成長したWC粒子やポアの存在は全く観
察されず、さらに400Kg／mm2の高い抗折力を示す
ものであつた。
これに対して、原料粉末として、Co粉末とWC
粉末の混合粉末を使用する以外は、上記の本発明
法２と同一の条件で従来法２を行なつた。この従
来法２では、WC粒子の平均粒径：0.9μｍを示
し、異常成長したWC粒子が散在し、WCおよび
Coの分散も悪く、さらに研摩面にはポアが存在
した組織を有し、かつ260Kg／mm2の抗折力しか示
さないWC基超硬合金しか製造することができな
かつた。
実施例 ３
同じくCo―Ｗ―Ｃ系化合物粉末を製造する目
的で、実施例１で用いたと同じCo粉末およびＷ
粉末のほかに、平均粒径：1.5μｍを有するW2C
粉末を用意し、これら粉末を、Co粉末：９％、
Ｗ粉末：10％、W2C粉末：81％の割合に配合
し、さらに別にCo粉末：24％、Ｗ粉末：25％、
W2C粉末：51％の割合で配合したものも用意
し、これら２種類の配合粉末を、それぞれボール
ミルにて24時間湿式混合し、乾燥した後、真空
中、温度：1000℃に１時間保持の条件で加熱する
ことによつて、Ｘ線回折で、それぞれ組成式：
Co3W9C4およびCo3W3Cを示す化合物を主成分と
して含有するCo―Ｗ―Ｃ系化合物粉末を製造し
た。
ついで、この結果得られたCo3W9C4系化合物粉
末およびCo3W3C系化合物粉末と、カーボンブラ
ツクとを、Co3W9C4系化合物粉末：35％、
Co3W3C系化合物粉末：61％、カーボンブラツ
ク：４％の割合で配合し、ボールミルにて48時間
湿式混合し、乾燥した後、圧粉体にプレス成形
し、この圧粉体を、真空中、温度：1280℃に1.5
時間保持の条件で焼結することによつて本発明法
３を実施した。この本発明法３により製造された
WC基超硬合金は、Co：18％を含有し、WC粒子
の平均粒径：0.3μｍを示し、かつWCとCoとが
きれいに分散し、異常成長したWC粒子やポアの
存在しない微粒組織を有し、抗折力も420Kg／mm2
を示すものであつた。
これに対して、従来法３として、平均粒径：
1.3μｍのCo粉末と同0.2μｍのWC粉末との混合
粉末を使用する以外は、上記本発明法３の製造条
件と同一の条件で製造したWC基超硬合金は、抗
折力：280Kg／mm2を示すにすぎず、また、その組
織も、WC粒子は0.8μｍの平均粒径を示すもの
の、異常成長したWC粒子が散在し、WCおよび
Coの分散も悪く、さらに研摩面上にポアが認め
られるものであつた。
実施例 ４
原料粉末として、実施例２で製造したCo2W4C
を主成分とする化合物粉末、平均粒径：1.3μｍ
のCo粉末、同0.2μｍのWC粉末、同1.1μｍのVC
粉末、同1.3μｍのTiC粉末、およびカーボンブ
ラツクを用意し、これら原料粉末を、それぞれ第
１表に示される配合組成に配合し、以後、実施例
１におけると同一の条件で本発明法４、５および
従来法４、５をそれぞれ実施した。
この結果得られた各種WC基超硬合金につい
て、Co含有量、WCおよびCoの分散状態、WC粒
子の平均粒径、ASTM規格にもとづくポアの状
態、並びに抗折力を測定および観察し、第１表に
合せて示した。
第１表に示されるように、この場合も実施例１
〜３におけると同様な結果を示し、本発明法４、
５によつて製造されたWC基超硬合金は、いずれ
In this invention, the average particle size of tungsten carbide (hereinafter referred to as WC) particles forming the dispersed phase is approximately 0.8 μm.
The present invention relates to a method for producing the following fine-grained WC-based cemented carbide having high strength and toughness. In general, WC-based cemented carbide is composed of WC particles that form a dispersed phase as a main component, and these are bonded with Co, which is a binder phase forming component, or furthermore, this is made up of WC particles that form a dispersed phase, which is a component of the periodic table. 4
One or more of carbides and nitrides of transition metals of groups a, 5a and 6a, and solid solutions of two or more of these (hereinafter collectively referred to as metal carbon/nitrides), are usually WC-based cemented carbide containing 0.1 to 20% (weight %, same hereinafter) is used as cutting tools, wear-resistant tools, impact-resistant tools, etc., and plays an important role in industry. Among these WC-based cemented carbides, especially
Fine WC particles with an average particle size of 1 μm or less have excellent performance when used as cutting tools with relatively low cutting speeds such as end mills, drills, and slitter knives, and as cold wear-resistant tools. However, due to the recent demand for improved productivity, the particles have been made finer and have higher strength and toughness.
There is a trend toward demand for WC-based cemented carbide. Furthermore, this type of WC-based cemented carbide with fine WC particles usually uses a mixed powder consisting of fine WC powder and Co powder, or a metal charcoal powder that has the effect of suppressing grain growth. It is manufactured by sintering using a powder metallurgy method using a mixed powder containing one or more powders of nitrides. However, some of the commercially available WC powders have an average particle size of about 0.5 μm, which is the finest, but this WC powder is easily oxidized, making it difficult to handle, and it also has poor quality stability. However, there is also the problem that when finer WC powder is used, cavities are likely to form in the sintered body, resulting in a decrease in strength.
In addition, in this type of WC-based cemented carbide, the crack propagation resistance at the interface between the dispersed phase and the binder phase is relatively high, but the crack propagation resistance at the interface between the dispersed phases is low. When used as a cutting tool, there is a problem that the cutting speed is slow, so the workpiece material is welded, and when the material is peeled off, fracture occurs at the interface between the dispersed phases, resulting in a decrease in toughness. Therefore, from the above-mentioned viewpoint, the present inventors conducted research to obtain a WC-based cemented carbide having high strength and high toughness by making the WC particles into fine particles. As long as WC powder is used as the WC powder, the average particle size of the WC particles in the resulting WC-based cemented carbide will be approximately 0.8 μm even if metal carbon/nitride powder, which has the effect of suppressing grain growth, is blended.
is the limit and cannot be made into finer particles than this, and as long as Co powder is used as the raw material powder, it is ductile and cannot be completely pulverized during mixing, resulting in coarse Co particles. It remains and causes the formation of cavities in the sintered body, and further WC
Since it is impossible to avoid contact between WC powder and Co powder when mixing powder and Co powder, interfacial destruction in the sintered body cannot be completely prevented. 7 W 6 etc.
Co--W compounds, Co 3 W 3 C, Co 6 W 6 C,
When using powders of Co-W-C compounds such as Co 2 W 4 C and Co 3 W 9 C 4 , these compound powders have brittle characteristics unique to intermetallic compounds, so they cannot be easily pulverized. When this is mixed with carbon powder and sintered as a green compact, these compounds easily decompose to form WC and Co.
If the sintering conditions are adjusted to prevent grain growth after WC formation, the average particle size of WC particles will be approximately 0.8 μm.
Not only does it have the following extremely fine grain structure,
Since there is very little adhesion between WC particles and the binder phase is formed by precipitated Co like the WC particles, a WC-based cemented carbide can be obtained in which there are almost no coarse Co particles that can cause cavities. As a result, we obtained the knowledge that the WC-based cemented carbide has high strength and toughness. This invention was made based on the above knowledge, and when producing WC-based cemented carbide by powder metallurgy, Co--W compound powder and Co--W-C compound powder are used as raw material powder. One or more of them are blended with carbon powder in an amount necessary to combine with W in these compounds to produce WC, taking into account the amount of decarburization and carburization during sintering. Mixed powder or additional WC
For the purpose of suppressing particle growth and improving the wear resistance, heat resistance, and corrosion resistance of the alloy, one or more powders of metal carbons and nitrides are preferably added in an amount of 0.1 to 20%. Using a mixed powder made by blending, and making this mixed powder into a compact,
By sintering preferably at a temperature of 1350°C or lower and decomposing the compound to generate WC and Co during sintering, the average particle size of the WC particles is about 0.8.
It is characterized by producing a WC-based cemented carbide having high strength and toughness with fine grains of micrometers or less. Note that Co used in the method of this invention
- W-based compound powder and Co--W--C based compound powder include, for example, Co powder and W powder, or Co powder, W powder, and carbon source powder such as WC and W 2 C, or cobalt oxide powder and tungsten oxide. It can be produced by blending powder and carbon powder into a predetermined composition and heating the mixture to a predetermined temperature within the range of 800 to 1300°C in a non-oxidizing atmosphere. The composition of the cemented carbide is, for example, Co 3 W as the raw material powder.
If powder is used, the Co content in the alloy after sintering is
47%, similarly 23% for Co 3 W 3 C, Co 2 W 4 C
Since it is 13% for Co 3 W 9 C 4 and 9% for Co 3 W 9 C 4 , a predetermined composition can be obtained by appropriately combining these raw material powders. Furthermore, if the sintered WC-based cemented carbide is subjected to hot isostatic pressure treatment to remove the few remaining cavities, the properties can be further improved. Next, the method of the present invention will be specifically explained using examples. Example 1 For the purpose of preparing a Co—W-based compound, Co powder with an average particle size of 1.3 μm and W powder with an average particle size of 1.0 μm were prepared, and these powders were mixed with Co powder: 27%, W powder:
After blending at a ratio of 73% and dry mixing, the powder was maintained at 900° C. for 3 hours in a hydrogen stream of 1 atm to produce a Co—W compound powder. this
Co--W compound powder was determined by X-ray diffraction to be Co 7 W 6
It was found that it has a single composition of Next, this
Co-W compound powder is mixed with 4.6% carbon black, wet-mixed in a ball mill for 24 hours to obtain a mixed powder, dried, and then press-molded into a green compact. Method 1 of the present invention was carried out by sintering at a temperature of 1280° C. for 2 hours. The WC-based cemented carbide obtained by method 1 of the present invention contains 26% Co, has a structure in which WC and Co are neatly dispersed, and has extremely fine WC particles with an average particle size of 0.3 μm. No abnormally grown WC particles or pores were observed. On the other hand, for the purpose of comparison, WC powder with an average particle size of 0.55 μm was ground in a ball mill to make it 0.2 μm, and WC powder with an average particle size of 1.3 μm.
The above method of the present invention 1 except that Co powder of
Conventional method 1 was carried out under the same conditions as . Although the WC-based cemented carbide produced by this conventional method 1 has WC particles with an average particle size of 0.8 μm, there are scattered WC particles that have grown abnormally to several μm, and the dispersion of the WC particles is poor. Pores were observed on the polished surface. Note that the WC-based cemented carbide manufactured by the method 1 of the present invention exhibits an extremely high resistance of 480 Kg/mm 2 , while that manufactured by the conventional method 1
It showed only a low resistance force of 300Kg/mm 2 . Example 2 First, for the purpose of producing a Co-W-C compound powder, the same Co powder and W used in Example 1 were used.
In addition to the powder, unground WC powder was used, and these powders were blended in a ratio of Co powder: 14%, W powder: 64%, and WC powder: 22%, and after dry mixing, in a vacuum at a temperature of: The mixture was heated at 1000° C. for 2 hours to produce a Co--W--C based compound powder whose main component was a compound having the compositional formula: Co 2 W 4 C by X-ray diffraction. Next, 4.1 was applied to this Co-W-C compound powder.
% of carbon black is blended and processed in a ball mill.
Wet-mix for 48 hours, dry to obtain a mixed powder, and mold a green compact from this mixed powder in a vacuum at a temperature of:
Method 2 of the present invention was carried out by sintering at 1290° C. for 1 hour. The WC-based cemented carbide produced by method 2 of the present invention contains 13% Co,
Moreover, it has a structure in which WC and Co are neatly dispersed, and the WC particles are fine particles with an average particle size of 0.2 μm, and no abnormally grown WC particles or pores were observed. It exhibited high transverse rupture strength. On the other hand, Co powder and WC powder are used as raw material powder.
Conventional method 2 was carried out under the same conditions as method 2 of the present invention described above, except that a mixed powder of powders was used. In this conventional method 2, the average particle size of WC particles was 0.9 μm, and abnormally grown WC particles were scattered, and WC and
The dispersion of Co was poor, and the polished surface had a structure with pores, and it was only possible to produce a WC-based cemented carbide that exhibited a transverse rupture strength of only 260 Kg/mm 2 . Example 3 For the purpose of producing a Co-W-C compound powder, the same Co powder and W used in Example 1 were used.
Besides the powder, W2C with average particle size: 1.5μm
Prepare powders and combine these powders with Co powder: 9%,
W powder: 10%, W2C powder: 81%, Co powder: 24%, W powder: 25%,
A mixture of W 2 C powder at a ratio of 51% was also prepared, and these two types of blended powder were wet mixed in a ball mill for 24 hours, dried, and then kept in a vacuum at a temperature of 1000℃ for 1 hour. By heating under the conditions of X-ray diffraction, the composition formula:
A Co--W--C based compound powder containing Co 3 W 9 C 4 and Co 3 W 3 C compounds as main components was produced. Next, the resulting Co 3 W 9 C 4 compound powder and Co 3 W 3 C compound powder were mixed with carbon black, Co 3 W 9 C 4 compound powder: 35%,
Co 3 W 3 C compound powder: 61%, carbon black: 4% were blended, wet mixed in a ball mill for 48 hours, dried, and then press-molded into a green compact. In vacuum, temperature: 1.5 to 1280℃
Inventive method 3 was carried out by sintering under time holding conditions. Produced by this invention method 3
The WC-based cemented carbide contains 18% Co, exhibits an average grain size of WC particles of 0.3 μm, and has a fine grain structure in which WC and Co are neatly dispersed and there are no abnormally grown WC particles or pores. The transverse rupture strength is also 420Kg/mm 2
It was indicative of this. On the other hand, as conventional method 3, the average particle size:
The WC-based cemented carbide manufactured under the same manufacturing conditions as the method 3 of the present invention described above except for using a mixed powder of 1.3 μm Co powder and 0.2 μm WC powder had a transverse rupture strength of 280 Kg/ mm 2 , and its structure also shows that although the WC particles have an average particle size of 0.8 μm, abnormally grown WC particles are scattered, and the WC and
Co dispersion was poor, and pores were observed on the polished surface. Example 4 Co 2 W 4 C produced in Example 2 as raw material powder
Compound powder mainly composed of, average particle size: 1.3μm
Co powder, 0.2 μm WC powder, 1.1 μm VC powder
TiC powder, 1.3 μm TiC powder, and carbon black were prepared, and these raw material powders were blended into the compositions shown in Table 1. Thereafter, the method 4 of the present invention was carried out under the same conditions as in Example 1. 5 and conventional methods 4 and 5 were carried out, respectively. For the various WC-based cemented carbides obtained as a result, we measured and observed the Co content, the dispersion state of WC and Co, the average particle size of WC particles, the state of pores based on ASTM standards, and the transverse rupture strength. It is shown in Table 1. As shown in Table 1, also in this case Example 1
-3 showed similar results, and the present method 4,
The WC-based cemented carbide produced by
【表】
も微粒組織を有し、高強度および高靭性をもつこ
とが明らかである。
実施例 ５
原料粉末として、実施例３で製造したCo3W9C4
系化合物粉末とCo3W3C系化合物粉末、および平
均粒径：1.3μｍを有する（Ta、Nb）CN粉末
（TaC／NbN＝７／３、重量比）、さらにカーボン
ブラツクを用い、これら粉末を、Co3W9C4系化合
物粉末33％、Co3W3C系化合物粉末：58％、
（Ta、Nb）CN粉末：５％、カーボンブラツク：
４％の割合に配合し、かつ焼結温度を1340℃とす
る以外は実施例２におけると同一の条件で本発明
法６を実施した。この本発明法６により得られた
WC基超硬合金は、Co含有量：16％、WC粒子の
平均粒径：0.25μｍを示し、WCとCoが均一微細
に分散し、その中にやや粗い（Ta、Nb）CN粒子
が均一に分散した組織を有し、ポアは認められな
いものであつた。また、この合金は抗折力：370
Kg／mm2を示した。
これに対して、従来法６として、上記の
（Ta、Nb）・CN粉末のほかに、実施例４で用いた
と同じWC粉末とCo粉末を用いる以外は、上記の
本発明法６と同一の条件で行なつた結果得られた
WC基超硬合金は、WC粒子の平均粒径：0.8μｍ
を示すが、抗折力：260Kg／mm2を示すにすぎず、
かつWCとCoの分散が悪く、Ａ―２程度のポアが
存在するものであつた。
上述のように、この発明の方法によれば、原料
粉末として、少なくともCo―Ｗ系化合物粉末お
よびCo―Ｗ―Ｃ系化合物粉末と、炭素粉末を使
用し、焼結時にWCとCoとを分解生成されるの
で、得られたWC基超硬合金は、WC粒子の平均
粒径が約0.8μｍ以下の微粒となるばかりでな
く、WCとCoとが均一微細に分散した組織を有す
るようになり、かつポアがほとんど存在しないか
ら、高強度と高靭性を具備するようになるなど工
業上有用な特性をもつたWC基超硬合金を製造す
ることができるのである。It is clear that [Table] also has a fine grain structure and has high strength and toughness. Example 5 Co 3 W 9 C 4 produced in Example 3 as raw material powder
Co 3 W 3 C based compound powder, (Ta, Nb)CN powder having an average particle size of 1.3 μm (TaC/NbN=7/3, weight ratio), and carbon black were used to prepare these powders. , Co 3 W 9 C 4 compound powder: 33%, Co 3 W 3 C compound powder: 58%,
(Ta, Nb)CN powder: 5%, carbon black:
Method 6 of the present invention was carried out under the same conditions as in Example 2, except that the ratio was 4% and the sintering temperature was 1340°C. Obtained by this invention method 6
The WC-based cemented carbide has a Co content of 16% and an average particle size of WC particles of 0.25 μm, in which WC and Co are uniformly and finely dispersed, and slightly coarse (Ta, Nb) CN particles are uniformly dispersed therein. It had a dispersed structure and no pores were observed. Also, this alloy has transverse rupture strength: 370
Kg/ mm2 . On the other hand, conventional method 6 is the same as method 6 of the present invention, except that the same WC powder and Co powder used in Example 4 are used in addition to the (Ta, Nb)/CN powder described above. The results obtained under the conditions
WC-based cemented carbide has an average particle size of WC particles: 0.8μm
However, it only shows a transverse rupture strength of 260Kg/ mm2 ,
Moreover, the dispersion of WC and Co was poor, and pores of about A-2 size were present. As described above, according to the method of the present invention, at least Co--W compound powder, Co--W--C compound powder, and carbon powder are used as raw material powders, and WC and Co are decomposed during sintering. As a result, the resulting WC-based cemented carbide not only has fine WC particles with an average grain size of about 0.8 μm or less, but also has a structure in which WC and Co are uniformly and finely dispersed. , and because there are almost no pores, it is possible to produce WC-based cemented carbide with industrially useful properties such as high strength and toughness.
Claims (1)
金を製造するに際して、原料粉末として、Co―
Ｗ系化合物粉末およびCo―Ｗ―Ｃ系化合物粉末
のうちの１種または２種以上と、炭素粉末からな
る混合粉末を使用し、焼結時に前記化合物を分解
させて炭化タングステンとCoとを生成せしめる
ことを特徴とする炭化タングステン粒子が微粒に
して、高強度および高靭性を有する炭化タングス
テン基超硬合金の製造法。 ２ 粉末冶金法により炭化タングステン基超硬合
金を製造するに際して、原料粉末として、Co―
Ｗ系化合物粉末およびCo―Ｗ―Ｃ系化合物粉末
のうちの１種または２種以上と、炭素粉末と、周
期律表の４ａ，５ａおよび６ａ族の遷移金属の炭
化物および窒化物、並びにこれらの２種以上の固
溶体のうちの１種または２種以上の粉末からなる
混合粉末を使用し、焼結時に前記化合物を分解さ
せて炭化タングステンとCoとを生成せしめるこ
とを特徴とする炭化タングステン粒子が微粒にし
て、高強度および高靭性を有する炭化タングステ
ン基超硬合金の製造法。[Claims] 1. When producing a tungsten carbide-based cemented carbide by a powder metallurgy method, Co-
Using a mixed powder consisting of one or more of W-based compound powder and Co-W-C-based compound powder and carbon powder, the compound is decomposed during sintering to generate tungsten carbide and Co. 1. A method for producing a tungsten carbide-based cemented carbide having high strength and toughness by finely granulating tungsten carbide particles. 2. When manufacturing tungsten carbide-based cemented carbide by powder metallurgy, Co-
One or more of W-based compound powder and Co-W-C-based compound powder, carbon powder, carbides and nitrides of transition metals of groups 4a, 5a and 6a of the periodic table, and these Tungsten carbide particles are characterized in that a mixed powder consisting of one or more powders of two or more solid solutions is used, and the compound is decomposed during sintering to generate tungsten carbide and Co. A method for producing fine-grained tungsten carbide-based cemented carbide having high strength and toughness.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58147571A JPS6039137A (en) | 1983-08-12 | 1983-08-12 | Manufacture of tungsten carbide-base sintered hard alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58147571A JPS6039137A (en) | 1983-08-12 | 1983-08-12 | Manufacture of tungsten carbide-base sintered hard alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6039137A JPS6039137A (en) | 1985-02-28 |
| JPS6245295B2 true JPS6245295B2 (en) | 1987-09-25 |
Family
ID=15433363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58147571A Granted JPS6039137A (en) | 1983-08-12 | 1983-08-12 | Manufacture of tungsten carbide-base sintered hard alloy |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6039137A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993005191A1 (en) * | 1991-09-02 | 1993-03-18 | Sumitomo Electric Industries, Ltd. | Hard alloy and production thereof |
| US5304342A (en) * | 1992-06-11 | 1994-04-19 | Hall Jr H Tracy | Carbide/metal composite material and a process therefor |
| WO1998040525A1 (en) * | 1997-03-10 | 1998-09-17 | Widia Gmbh | Hard metal or cermet sintered body and method for the production thereof |
-
1983
- 1983-08-12 JP JP58147571A patent/JPS6039137A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6039137A (en) | 1985-02-28 |
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