JP4177468B2 - High hardness hard alloy and its manufacturing method - Google Patents
High hardness hard alloy and its manufacturing method Download PDFInfo
- Publication number
- JP4177468B2 JP4177468B2 JP28307496A JP28307496A JP4177468B2 JP 4177468 B2 JP4177468 B2 JP 4177468B2 JP 28307496 A JP28307496 A JP 28307496A JP 28307496 A JP28307496 A JP 28307496A JP 4177468 B2 JP4177468 B2 JP 4177468B2
- Authority
- JP
- Japan
- Prior art keywords
- hard alloy
- raw material
- high hardness
- powder
- binder phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Powder Metallurgy (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、高硬度のＷＣ基超硬合金とその製造方法に関するものである。
【０００２】
【従来の技術】
一般的に硬質相がＷＣを主体とし結合相をＣｏ、Ｎｉなどの鉄族金属とする硬質合金はＷＣ基超硬合金と呼ばれる。この硬質合金は一般的に1350℃以上1500℃以下の温度で１時間ほど真空中で無加圧で保持され、焼結が行われる。場合によってはその後、焼結温度よりも低い温度でＨＩＰ（熱間静水圧プレス処理）がなされることもある。このような焼結条件下では液相が生成し、ＷＣ粒は溶解再析出現象により焼結中に粒成長を起こしやすいことが知られている。
【０００３】
このため、微粒のＷＣを必要とする用途の合金を製造するには、微粒原料を使用し、粒成長抑制のためＶＣ、Ｃｒ3 Ｃ2 、ＮｂＣ、ＴａＣ、ＴｉＣなどの化合物を添加して、緻密化できる限界の低温で焼結することが行われてきた（特開平1-215947号公報、同4-289146号公報、同 5-98385号公報など参照）。
【０００４】
【発明が解決しようとする課題】
これらの技術では確かにＷＣの微粒化はある程度実現されたが、工業的に安定して得られたＷＣの平均粒径は 0.5μm程度が限界であった。
従って、本発明の主目的は、より微粒のＷＣを有し、粒成長抑制材を極力含まない超硬合金とその製造方法を提供することにある。
【０００５】
【課題を解決するための手段】
この目的を達成するため、本発明の硬質合金は、ＷＣからなる硬質相と、鉄族金属からなる結合相とを具える硬質合金において、ＷＣの平均粒径が0.4 μ mより小さく、Ｃｒ、Ｖ、Ｃｒの炭化物、Ｖの炭化物を合計で結合相量の１wt％以下しか含まないことを特徴とする。ＷＣの平均粒径の下限は0.1μm程度、より好ましくは約0.01μmである。もちろん、本発明は合金中の不可避的不純物の存在を否定するものではない。不可避的不純物には、例えばＡｌ，Ｂａ，Ｃａ，Ｃｕ，Ｆｅ，Ｍｇ，Ｍｎ，Ｎｉ，Ｓｉ，Ｓｒ，Ｓ，Ｏ，Ｎ，Ｍｏ，Ｓｎ，Ｃｒ等が挙げられる。
【０００６】
このような硬質合金は、さらに次の各要件を単独で、または複合して具えることが好適である。
(1) 理論密度比が98％以上である。
このような緻密度を有する硬質合金は優れた曲げ強度も具える。
【０００７】
(2) 結合相量が 0.1〜２wt％である。
従来、結合相量を２wt％未満とすると焼結性が極端に低下し、緻密な焼結体を得ることができなかった。後述する本発明製造方法では結合相量が極端に少ない場合でも安定して焼結が可能で、強度・靱性・硬度に優れた焼結体が得られる。
【０００８】
硬質合金が、層状形状で、上部層と下部層との間に厚さを有する場合に以下を満たす。
(3)− I硬質合金の上部層におけるＷＣの平均粒径が0.4 μ mより小さく、下部層におけるそれが0.4 μ m以上であるように厚さ方向にＷＣの平均粒径が変化されている。
(3)− II硬質合金の上部層における結合相量が0.1〜２wt％の範囲にあり、下部層におけるそれが同範囲にないように厚さ方向に組成が変化されている。
【０００９】
一面側と他面側とで硬度や靱性の異なる硬質合金は従来より提案されているが、従来の焼結法では硬質相の粒成長および焼結中の液相の移動が激しく、狙いとする合金を作製することが難しかった。後述する本発明方法では、焼結中の硬質相の粒成長、液相の移動が少ないため、厚さ方向にＷＣの粒径や結合層量の異なる硬質合金を作製することができる。なお、これらの組成の変化の仕方には、段階的なものと実質上連続的なものとの双方を含む。
【００１０】
(4) 金属材料の基体上に接合されている。
従来、焼結体と金属基体とのろう付けによる接合では接合強度が不十分だったが、焼結接合することにより、高い接合強度が得られると共に、ろう付け工程を省略することができる。
【００１１】
上記の硬質合金の製造方法は、ＷＣからなる硬質相、鉄族金属からなる結合相および結合相量の１wt％以下の粒成長抑制材の各原料粉末を混合する工程と、この混合粉末から構成される原料部材を通電加熱装置に配置する工程と、この原料部材を1100℃〜1350℃、 5 〜200MPaで通電加圧焼結する工程とを具えることを特徴とする。前記原料粉末を混合する工程において、ＷＣは、平均粒径が 0.5 μ m より小さい粉末 ( 但し、 0.4 μ m 以上を除く ) を用いる。
【００１２】
ここで、粒成長抑制材としては、Ｃｒ、Ｖ、Ｃｒの炭化物、Ｖの炭化物などが挙げられる。また、原料部材には、原料の粉末自体や、予めプレスした圧粉体、中間焼結体、これらの積層体などが含まれる。
上記の焼結は液相の存在下で行うことが望ましい。
【００１３】
この製造方法は、通電加圧焼結法などにより急速昇温し、低温で短時間の焼結を行えば、ＷＣの粒成長を抑制でき、ＷＣの微粒化が実現できるのではないかとの考えに基づいてなされたものである。実際に後述する焼結テストを行ったところ、ＷＣの平均粒径が0.5μm 以下の合金を作製できた。
【００１４】
ところが、この合金を作製する際に従来技術と同様にして粒成長抑制材（ＶＣやＣｒの炭化物）を添加して焼結を行ったところ、抗折力が従来技術で作製した合金よりも低強度のものしか得られないことが判明した。そこで、本発明者らはこの原因を鋭意検討し、ＶＣやＣｒの炭化物の凝集体が要因と思われる異常な組織が原因で低強度となっていることを究明した。
【００１５】
そのため、粒成長抑制材の添加量を結合相量に対して１wt％以下とした上で、微粒ＷＣ合金の作製を試みた。その結果、従来よりも微粒のＷＣの合金を作製でき、しかも抗折力が従来よりも高い合金を作製できることを見いだした。なお、Ｃｒ、Ｖ、Ｃｒの炭化物、Ｖの炭化物の添加量は無添加が望ましいが、ＷＣや鉄族金属の原料粉末中に不可避不純物の形でＣｒやＶが混入することが考えられる。そのため、これら粒成長抑制材の合計含有量を結合相量に対して 0.3wt％以下とすることがより好ましい。
【００１６】
本発明方法によって得られる合金のＷＣ粒径は使用する原料のＷＣ粒径に主に依存する。現状技術では直接炭化法で作製したＷＣ粉末や粉砕工程で微細化したＷＣ粉末を用いればよい。今後さらに微粒のＷＣ粉末が開発された際にも本発明を適用することで一層微粒のＷＣを有する超硬合金を作製できる。
【００１７】
焼結条件は次のような理由で限定した。
焼結温度は、1100℃未満では緻密化が進行しにくく、1350℃を越えると液相のシミ出しが生じやすくなるためである。なお、ここでいう焼結温度は焼結炉を制御するときの黒鉛型表面の温度のことを指し、実際の試料温度はこの温度よりも 150℃〜300 ℃程度高い温度になっているものと思われる。
【００１８】
また、加圧力は、５MPa 未満では加圧焼結の効果が見られず、200MPaより加圧力を大きくすることは設備的に難しく、コストアップの要因となるためである。特に好ましいのは10〜50MPa の範囲である。これは安価な黒鉛型を用いることが可能なためである。
【００１９】
さらに、焼結時間は10分以内であることが好ましい。焼結時間を短くすることで硬質相の粒成長および焼結中の液相の移動を抑制し、厚さ方向にＷＣの粒径や結合相量の異なる硬質合金を作製することができる。より好ましくは５分以内である。
なお、焼結雰囲気は0.1torr以下の真空が好ましい。
【００２０】
ＷＣの平均粒径や組成が厚さ方向に組成が変化する硬質合金を製造するには、硬質相粒径の異なる複数種の混合粉末や結合相量の異なる複数種の混合粉末を準備しておけばよい。そして、これらを通電加熱装置に配置する工程において、これら複数種の混合粉末をＷＣ粒子の粒径順（結合相の含有量順）に積層して配置する。準備された混合粉末の種類が少なければ、厚さ方向に段階的に組成の異なる硬質合金を得ることができ、この種類を多くして積層される各層の厚みを薄くすれば実質上連続的に組成の変化する硬質合金を得ることができる。
【００２１】
また、このような傾斜組成硬質合金を基体上に接合するには、基体と共に原料部材を通電加圧装置に配置すればよい。その際、接合面側のＷＣの粒径を大きく（結合相量を多く）、その反対面側の粒径を小さく（結合相量を多く）することが望ましい。
【００２２】
【発明の実施の形態】
以下本発明の実施の形態を説明する。
（実施例１）
平均粒径0.25μmのＷＣ粉末、平均粒径１μmのＣｏ粉末、平均粒径１μmのＶＣ粉末、平均粒径 1.5μmのＣｒ3 Ｃ2 粉末を準備し、表１に記載した組成に配合し、アトライターで10時間混合粉砕して混合粉末（原料No.1-1〜1-9) を作製した。これらの混合粉末を１ton ／cm2 の圧力で金型プレスし、プレス体を焼結炉にセットして、0.01Torr以下の真空中の昇温速度10℃／min 、最高キープ温度1350℃、キープ時間１時間、冷却速度５℃／min の条件（従来の液相焼結法条件）で焼結し、25×８×５mmの形状の焼結体（試料 No.１〜９）を得た。
【００２３】
【表１】
これらの焼結体は平面研削、鏡面研磨後、ＦＥ−ＳＥＭにより組織写真撮影を行い、撮影した写真を用いてフルマンの式により、ＷＣの平均粒子径を算出した。また、20mmスパンの３点曲げ試験で曲げ強度も測定した。これらの測定結果を表２に示す。
【００２５】
次に、原料 No.1-1〜1-9 を用いて、通電加熱焼結装置により 50MPaの圧力を上下方向から負荷しながら昇温スピード 190℃／min となるように黒鉛型に電流を通じ、1130℃に達した時点で５分間キープし、約 100℃／min の速度で冷却を行うことによって硬質合金（試料 No.10〜18 ）を作製した。これらの試料も同様にして、ＷＣの平均粒度と曲げ強度を測定した。その結果も表２に示す。
【００２６】
【表２】
その結果、従来焼結法で得られた超硬合金における最小のＷＣ平均粒度はＶＣを添加した場合（試料 No.１）の 0.5μmであるのに対して、通電加圧焼結法によるものでは原料組成に関わらず全て0.3μm であった。図１に試料No.18 を平面研削し、鏡面研磨してから撮影したＦＥ−ＳＥＭ写真を示す。図において、白い粒子状のものがＷＣである。写真中に示す１μmのスケールとＷＣ粒の大きさを比較すればその粒径が極めて微細であることがわかる。
【００２８】
ところが、通電加圧焼結法によるものでも結合相量に対して１wt％を越えるＶＣやＣｒ3 Ｃ2 を添加した合金については、ＷＣ粒度が微細にも関わらず曲げ強度が著しく低下していることが判明した。ただし、ＶＣやＣｒ3 Ｃ2 を結合相量に対して１wt％以下の含有量とした試料 No.12、13、16、17、18の合金は非常に優れた曲げ強度を実現し、従来焼結法以上の曲げ強度を実現できることが判明した。
【００２９】
なお、本実施例で行った通電加圧焼結法での実際の試料温度はＰＲ熱電対による測定の結果、約1380℃であることが判明した。この温度はＷＣ基超硬合金の共晶組成の融点1320℃を上回っており、少なくとも部分的には液相が出現していたものと考えられる。
【００３０】
（実施例２）
固相焼結を行うため、実施例１で行った通電加圧焼結の条件の中で、最高キープ温度を1000℃、保持時間を60分に変更した焼結を前記原料No.1-1〜1-9を用いて行い、試料 No.2-1〜2-9 を作製した。これらの焼結体を用いて、実施例１と同様にしてＷＣの平均粒度、曲げ強度を測定した結果を表３に記す。
【００３１】
【表３】
これらの結果、固相焼結により、作製した焼結体は微細なＷＣを有する焼結体とできているが、曲げ強度が非常に低く、液相を出現させて焼結した通電加圧焼結よりも特性が劣ることがわかる。
【００３３】
（実施例３）
実施例１で用いた原料粉末No.1-9を用いて、実施例１の通電加圧焼結条件のうち、最高キープ温度のみを変化させ、1000〜1400℃で焼結した試料No.3-1〜3-7を作製した。これらの試料のＷＣの平均粒度、曲げ強度を実施例１と同様にして測定し、比重をアルキメデス法により測定した。なお、ＷＣの比重を15.6ｇ／cm3、Ｃｏの比重を8.9ｇ／cm3、Ｃｒ3Ｃ2の比重を6.7ｇ／cm3として、本組成の合金の理論密度を計算すると14.5ｇ／cm3となる。これをもとに、それぞれの焼結条件で作製した合金の理論密度比を算出した。以上の測定，算出結果を表４に示す。
【００３４】
【表４】
表４より、理論密度比が98％を越えた緻密な合金は優れた曲げ強度を実現することが判明した。また、焼結温度としては、1100℃〜1350℃の範囲がＷＣ粒径、曲げ強度の観点で好ましいことも判明した。
【００３６】
（実施例４）
実施例１で使用したＷＣ粉、Ｃｏ粉を用いて表５の組成とし、実施例１と同様に２種類の焼結条件（通電加圧法の最高キープ温度のみ1250℃に変更）で試料 No.4-1〜4-10を作製した。実施例３と同様にしてこれらの試料の理論密度比を求めた。また、これらの焼結体を平面研削後、鏡面研磨し、ダイヤモンド製ビッカース圧子を用いて50kg荷重でＨｖ硬度も測定した。これらの結果を表５に記載する。
【００３７】
【表５】
表５の結果より通電加圧焼結法によると２wt％以下の結合相の硬質合金でも緻密に焼結でき、Ｈｖ硬度の高い合金を作製できることがわかる。
【００３９】
（実施例５）
硬質相としてＷＣ、結合相としてＣｏを10wt％、Ｎｉを２wt％含む粉末をＷＣ粒径の大きさに分けて２種類用意し、黒鉛型中にＷＣ粒径が大きい粉末（平均粒径 2.5μm）が下部層、小さい粉末（平均粒径0.25μm）が上部層となるように層状にプレスして充填した。そして、 41MPaの圧力を上下方向から負荷しながら昇温スピード 300℃／分となるように黒鉛型に電流を通じ、1130℃に達した時点で６分間キープし、 100℃／min の条件で冷却を行うことによって硬質合金を作製した。
【００４０】
得られた直径30mm、厚み８mmの円板状焼結体断面を＃ 250の砥石で平面研削後、鏡面研磨して光学顕微鏡により観察した。その結果、上部層のＷＣの平均粒径は0.30μmと非常に小さく、下部層のＷＣの平均粒径は約３μmと大きくなっていた。
【００４１】
また、ＥＰＭＡにて組成分析を行ったが、各層間でのＣｏ、Ｎｉ元素の移動は比較的少なく、従来の製造法による焼結体で問題があった層間の成分の拡散が抑制されていた。
【００４２】
ＷＣ基超硬合金はＷＣ粒径が小さいほど硬度が高くＷＣ粒径が大きいほど靱性が高くなることから、本構造の焼結体は上部側で耐摩性に優れ下部側で靱性に優れるため、通常相反する両特性を両立することのできる材料となっている。
【００４３】
（実施例６）
硬質相として平均粒径0.25μmのＷＣ、結合相としてＣｏを12wt％含んだ粉末とＣｏを２wt％含んだ粉末とを用意し、Ｃｏを２wt％含んだ粉末が上部層となるようにそれらを層状にプレスして黒鉛型に充填した。そして、 60MPaの圧力を上下方向から負荷しながら昇温スピード 100℃／分となるように黒鉛型に電流を通じ、1250℃に達した時点で10分間キープし、 200℃／min の速度で冷却を行うことによって硬質合金を作製した。
【００４４】
得られた直径30mm、厚み８mmの円板状焼結体断面を＃ 250の砥石で平面研削後、鏡面研磨して光学顕微鏡により観察した。その結果、上部層、下部層ともに、ＷＣの平均粒径は0.30μmと非常に小さく、上部層でのＨｖ硬度は25GPa 、下部層でのＨｖ硬度は18.5GPa となっていた。
【００４５】
また、ＥＰＭＡにて組成分析を行ったが、各層間でのＣｏ元素の移動は比較的少なく、従来の製造法による焼結体で問題があった層間の成分の拡散が抑制されていた。
【００４６】
ＷＣ−Ｃｏの超硬合金はＣｏの含有率が低いほど耐摩耗性に優れ、Ｃｏの含有率が高いほど靱性が高くなることから、本構造の焼結体は上部側で耐摩性に優れ下部側で靱性に優れるため、通常相反する両特性を両立することのできる材料となっている。
【００４７】
（実施例７）
平均粒径0.25μmのＷＣ粉末と平均粒径１μmのＣｏ粉末を 2.0wt％含んだ混合粉末Ａと、平均粒径 2.5μmのＷＣ粉末と平均粒径１μmのＣｏ粉末を12wt％含んだ混合粉末Ｂを用意し、この二つの粉末を配合して表６に示すように５種類の粉末 No.5-1〜5-5 を作製した。
【００４８】
【表６】
これらの粉末を No.5-1 が上部側、 No.5-5 が下部側となるように順に黒鉛型内に充填した。そして、圧力を上下方向から負荷しながら昇温スピード 150℃／分となるように黒鉛型に電流を通じ、1130℃に達した時点で３分間キープし、 200℃／min の速度で冷却を行うことによって硬質合金を作製した。
【００５０】
得られた直径30mm、厚み10mmの円板状焼結体断面を＃ 250の砥石で平面研削後、鏡面研磨して光学顕微鏡により観察した。その結果、上部層のＷＣの平均粒径は0.30μmと非常に小さく、下部層のＷＣの平均粒径は約３μmと大きくなっており、中間層でのＷＣ粒径は約 0.3μmと微粒のＷＣと約３μmと粗粒のＷＣが混在する組織となっていることが確認できた。
【００５１】
また、ＥＰＭＡにて組成分析を行ったが、各層間でのＣｏ元素の移動は比較的少なく、上部層でＣｏ量が少なく、下部層でＣｏ量の多い傾斜積層構造となっており、従来の製造法による焼結体で問題があった層間の成分の拡散が抑制されていた。
【００５２】
ＷＣ−Ｃｏの超硬合金はＷＣ粒径が小さく、Ｃｏの含有率が低いほど硬度が高くかつ靱性が低くなり、ＷＣ粒径が大きく、Ｃｏの含有率が多いほど硬度が低くかつ靱性が高くなる。このことから、本構造の焼結体は上部側で耐摩性に優れ、下部側で靱性に優れており、通常相反する両特性を両立することのできる材料となっている。
【００５３】
（実施例８）
図２のように、平均粒径0.25μmのＷＣ粉末と平均粒径１μmのＣｏ粉末を20wt％含んだ混合粉末１を黒鉛型２中で鋼の基体３の上に配置した。そして、上下部加圧ラム４，５により41MPaの圧力を上下方向から負荷しながら昇温スピードを190℃／分となるように黒鉛型２に電流を通じ、1130℃に達した時点で６分間キープし、約100℃／minの速度で冷却を行うことによって硬質合金を鋼上に接合した。なお、上下部加圧ラム４，５に接続されているのは電源６、黒鉛型２に設置されているのは熱電対７である。
【００５４】
得られた直径50mm、厚み20mmの円板状焼結体断面を＃ 250の砥石で平面研削後、鏡面研磨して光学顕微鏡により観察したところ、上部層のＷＣの平均粒径は0.30μmと非常に小さく、下部層のＷＣの平均粒径は約３μmと大きくなっていた。
【００５５】
また、ＥＰＭＡにて組成分析を行ったが、各層間でのＣｏ元素の移動は比較的少なく、従来の製造法による焼結体で問題があった層間の成分の拡散が抑制されていた。
【００５６】
本構造の焼結体は、上部層は粒径の細かいＷＣからなっているため高耐摩耗性で、下部層は鋼としたことにより高強度、高靱性を得ることができ、通常相反する両特性を両立することのできる材料となっている。
【００５７】
（実施例９）
実施例７で行ったのと同様にして、ＷＣ粒径、Ｃｏ量の異なる二種類の粉末Ａ，Ｂを用いて、これらの混合割合の異なる５種類の粉末の積層を鋼の基体上で行った。そして、41MPa の圧力を上下方向から負荷しながら昇温スピード 190℃／分となるように黒鉛型に電流を通じ、1130℃に達した時点で６分間キープし、約 100℃／min の速度で冷却を行うことによって硬質合金を鋼上に接合した。
【００５８】
得られた直径50mm、厚み30mmの円板状焼結体断面を＃ 250の砥石で平面研削後、鏡面研磨して光学顕微鏡により観察したところ、上部層のＷＣの平均粒径は0.30μmと非常に小さく、下部層のＷＣの平均粒径は約３μmと大きくなっていた。
【００５９】
また、ＥＰＭＡにて組成分析を行ったが、上部から下部層にかけてＣｏ含有量が５層で順に増加し、各層間でのＣｏ元素の移動は比較的少なく、従来の製造法による焼結体で問題があった層間の成分の拡散が抑制されていることが確認できた。
【００６０】
ＷＣ−Ｃｏの超硬合金はＷＣ粒径が小さく、Ｃｏの含有率が低いほど硬度が高くかつ靱性が低くなり、ＷＣ粒径が大きく、Ｃｏの含有率が多いほど硬度が低くかつ靱性が高くなる。このことから、本実施例の焼結体は、上部層は粒径の細かいＷＣと少量のＣｏからなっているため高耐摩耗性で、下部層は粒径の大きなＷＣと多量のＣｏからなる超硬合金、そして鋼層となっていることによって高強度、高靱性を得ることができ、通常相反する両特性を両立することのできる材料となっている。
【００６１】
【発明の効果】
以上説明したように、本発明硬質合金はＷＣの平均粒径が0.5μm よりも微細であるため、高硬度が要求される切削，耐摩耗工具などに利用することができる。特に、厚さ方向に組成の異なる合金とすることで、合金の一面側と他面側とで相反する特性を有する合金とできる。
【００６２】
また、本発明製造方法は、本発明硬質合金を製造するのに最適な方法で、短時間による焼結が可能なため、コストダウンに寄与できる。
【図面の簡単な説明】
【図１】本発明硬質合金の組織を示す走査型顕微鏡写真である。
【図２】本発明硬質合金を製造する装置の概略図である。
【符号の説明】
１ 混合粉末 ２ 黒鉛型 ３ 基体 ４ 上部加圧ラム ５ 下部加圧ラム
６ 電源 ７ 熱電対[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a WC-based cemented carbide having high hardness and a method for producing the same.
[0002]
[Prior art]
Generally, a hard alloy whose hard phase is mainly WC and whose binder phase is an iron group metal such as Co or Ni is called a WC-based cemented carbide. This hard alloy is generally held at a temperature of 1350 ° C. or higher and 1500 ° C. or lower for 1 hour in a vacuum without pressure, and sintered. In some cases, HIP (hot isostatic pressing) may be performed at a temperature lower than the sintering temperature. It is known that a liquid phase is generated under such sintering conditions, and WC grains are likely to undergo grain growth during sintering due to a dissolution and reprecipitation phenomenon.
[0003]
For this reason, in order to produce an alloy for applications requiring fine WC, a fine raw material is used, and compounds such as VC, Cr 3 C 2 , NbC, TaC, TiC are added to suppress grain growth, Sintering has been carried out at a low temperature that allows densification (see Japanese Patent Application Laid-Open Nos. 1-215947, 4-289146, and 5-98385).
[0004]
[Problems to be solved by the invention]
Although these techniques have certainly achieved WC atomization to some extent, the average particle diameter of WC obtained stably industrially is limited to about 0.5 μm.
Therefore, the main object of the present invention is to provide a cemented carbide having a finer WC and containing as little grain growth inhibitor as possible, and a method for producing the same.
[0005]
[Means for Solving the Problems]
To this end, the hard alloy of the present invention comprises a hard phase consisting of WC, in a hard alloy comprising a binding phase consisting of an iron group metal, the average particle size of the WC is smaller than 0.4 mu m, Cr, V and Cr carbides and V carbides are contained in a total of only 1 wt% or less of the amount of the binder phase. The lower limit of the average particle diameter of WC is about 0.1 μm, more preferably about 0.01 μm. Of course, the present invention does not deny the presence of inevitable impurities in the alloy. Inevitable impurities include, for example, Al, Ba, Ca, Cu, Fe, Mg, Mn, Ni, Si, Sr, S, O, N, Mo, Sn, Cr and the like.
[0006]
Such a hard alloy preferably further comprises the following requirements alone or in combination.
(1) The theoretical density ratio is 98% or more.
A hard alloy having such a fine density also has an excellent bending strength.
[0007]
(2) The amount of the binder phase is 0.1 to 2 wt%.
Conventionally, when the amount of the binder phase is less than 2 wt%, the sinterability is extremely lowered and a dense sintered body cannot be obtained. In the production method of the present invention described later, stable sintering is possible even when the amount of the binder phase is extremely small, and a sintered body excellent in strength, toughness and hardness can be obtained.
[0008]
The following is satisfied when the hard alloy has a layered shape and has a thickness between the upper layer and the lower layer.
(3) - an average particle size of the WC in the upper layer of the I hard alloy is less than 0.4 mu m, an average particle size of the WC in the thickness direction so that in the lower layer is at least 0.4 mu m is changed .
(3) - II binder phase content in the upper layer of the hard alloy is in the range of 0.1~2wt%, it in the lower layer are varied in composition in the thickness direction so as not to the same extent.
[0009]
Hard alloys with different hardness and toughness on the one side and the other side have been proposed in the past, but with the conventional sintering method, the grain growth of the hard phase and the movement of the liquid phase during sintering are intense, and the target is It was difficult to make an alloy. In the method of the present invention, which will be described later, since hard phase grain growth and liquid phase movement during sintering are small, hard alloys having different WC grain sizes and bonding layer amounts in the thickness direction can be produced. In addition, the method of changing these compositions includes both stepwise and substantially continuous.
[0010]
(4) Bonded on a metallic substrate.
Conventionally, the joining strength by the brazing of the sintered body and the metal substrate has been insufficient, but by joining the sintered body, a high joining strength can be obtained and the brazing step can be omitted.
[0011]
Method of manufacturing the hard alloy includes the steps of mixing the hard phase consisting of WC, each raw material powder of the binder phase and binder phase content of 1 wt% or less of the grain growth inhibiting material made of an iron group metal, composed from the mixed powder The raw material member is arranged in an electric heating device, and the raw material member is subjected to electric current pressure sintering at 1100 ° C. to 1350 ° C. and 5 to 200 MPa. In the step of mixing the raw material powders, WC has an average particle diameter of 0.5 mu m is smaller than powder (excluding more than 0.4 mu m) used.
[0012]
Here, examples of the grain growth inhibitor include Cr, V, a carbide of Cr, a carbide of V, and the like. The raw material member includes the raw material powder itself, a previously pressed green compact, an intermediate sintered body, and a laminate thereof.
The above sintering is desirably performed in the presence of a liquid phase.
[0013]
In this manufacturing method, it is thought that WC grain growth can be suppressed and WC atomization can be realized if rapid heating is performed by an electric pressure sintering method and sintering is performed at a low temperature for a short time. It was made based on. When a sintering test described later was actually performed, an alloy having an average particle diameter of WC of 0.5 μm or less could be produced.
[0014]
However, when this alloy was produced and sintered by adding a grain growth inhibitor (VC or Cr carbide) in the same manner as in the prior art, the bending strength was lower than that of the alloy produced by the prior art. It was found that only strong ones were obtained. Therefore, the present inventors diligently investigated this cause and found out that the strength is low due to an abnormal structure that seems to be caused by an aggregate of carbides of VC and Cr.
[0015]
Therefore, an attempt was made to produce a fine-grained WC alloy after the addition amount of the grain growth inhibitor was 1 wt% or less with respect to the amount of the binder phase. As a result, it has been found that an alloy of finer WC than that of the prior art can be produced and an alloy having a higher bending strength than that of the prior art can be produced. The addition amount of Cr, V, Cr carbide, and V carbide is preferably not added, but it is conceivable that Cr and V are mixed in the form of inevitable impurities in the raw material powder of WC or iron group metal. Therefore, it is more preferable that the total content of these grain growth inhibitors is 0.3 wt% or less with respect to the amount of the binder phase.
[0016]
The WC grain size of the alloy obtained by the method of the present invention mainly depends on the WC grain size of the raw material used. In the current technology, a WC powder produced by a direct carbonization method or a WC powder refined by a grinding process may be used. Even when finer WC powder is developed in the future, a cemented carbide having a finer WC can be produced by applying the present invention.
[0017]
The sintering conditions were limited for the following reasons.
This is because if the sintering temperature is less than 1100 ° C., densification hardly proceeds, and if it exceeds 1350 ° C., the liquid phase tends to stain. The sintering temperature here refers to the temperature of the graphite mold surface when controlling the sintering furnace, and the actual sample temperature is about 150 ° C to 300 ° C higher than this temperature. Seem.
[0018]
Also, if the applied pressure is less than 5 MPa, the effect of pressure sintering is not observed, and it is difficult to increase the applied pressure from 200 MPa in terms of equipment, which causes a cost increase. Particularly preferred is a range of 10-50 MPa. This is because an inexpensive graphite mold can be used.
[0019]
Furthermore, the sintering time is preferably within 10 minutes. To suppress the movement of the liquid phase in the grain growth and sintering of the hard phase by shortening the sintering time can be manufactured of WC in the thickness direction particle size and sintering Gosho different amounts of hard alloy. More preferably, it is within 5 minutes.
The sintering atmosphere is preferably a vacuum of 0.1 torr or less.
[0020]
In order to produce a hard alloy whose WC average particle size and composition changes in the thickness direction, a plurality of mixed powders having different hard phase particle sizes and a plurality of mixed powders having different binder phase amounts are prepared. Just keep it. And in the process of arrange | positioning these in an electric heating apparatus, these multiple types of mixed powder is laminated | stacked and arrange | positioned in the particle size order (content order of a binder phase) of WC particle | grains. If there are few kinds of mixed powders prepared, hard alloys having different compositions in the thickness direction can be obtained, and if this type is increased to reduce the thickness of each layer to be laminated, it will be substantially continuous. A hard alloy whose composition changes can be obtained.
[0021]
In addition, in order to join such a gradient composition hard alloy onto a substrate, the raw material member may be placed in an energizing and pressing device together with the substrate. At that time, it is desirable to increase the particle size of the WC on the bonding surface side (increase the amount of the binder phase) and decrease the particle size on the opposite surface side (increase the amount of the binder phase).
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
(Example 1)
WC powder having an average particle size of 0.25 [mu] m, Co powder having an average particle size of 1 [mu] m, VC powder having an average particle diameter of 1 [mu] m, to prepare a Cr 3 C 2 powder having an average particle diameter of 1.5 [mu] m, formulated into compositions shown in Table 1, The mixed powder (raw materials No. 1-1 to 1-9) was prepared by mixing and pulverizing with an attritor for 10 hours. These mixed powders are die-pressed at a pressure of 1 ton / cm 2 , the press body is set in a sintering furnace, the heating rate is 10 ° C / min in a vacuum of 0.01 Torr or less, the maximum keep temperature is 1350 ° C, and the keep is kept Sintering was performed for 1 hour at a cooling rate of 5 ° C./min (conventional liquid phase sintering method conditions) to obtain sintered bodies (sample Nos. 1 to 9) having a shape of 25 × 8 × 5 mm.
[0023]
[Table 1]
These sintered bodies were subjected to surface grinding and mirror polishing, and then a structure photograph was taken by FE-SEM, and the average particle diameter of WC was calculated by the Fullman equation using the taken pictures. The bending strength was also measured by a three-point bending test with a span of 20 mm. These measurement results are shown in Table 2.
[0025]
Next, using raw materials No. 1-1 to 1-9, current was passed through the graphite mold so that the heating rate was 190 ° C / min while applying a pressure of 50 MPa from the top and bottom with an electric heating and sintering machine. When the temperature reached 1130 ° C., it was kept for 5 minutes and cooled at a rate of about 100 ° C./min to produce a hard alloy (Sample Nos. 10 to 18). These samples were similarly measured for the average grain size and bending strength of WC. The results are also shown in Table 2.
[0026]
[Table 2]
As a result, the minimum WC average particle size in the cemented carbide obtained by the conventional sintering method is 0.5 μm when VC is added (sample No. 1), whereas it is based on the electric pressure sintering method. In all cases, the thickness was 0.3 μm regardless of the raw material composition. FIG. 1 shows an FE-SEM photograph taken after subjecting Sample No. 18 to surface grinding and mirror polishing. In the figure, white particles are WC. If the 1 μm scale shown in the photograph is compared with the size of the WC grains, it can be seen that the grain size is extremely fine.
[0028]
However, even in the case of an electric pressure sintering method, the bending strength of the alloy added with VC or Cr 3 C 2 exceeding 1 wt% with respect to the amount of the binder phase is remarkably lowered despite the fine WC grain size. It has been found. However, the alloys of Sample Nos. 12, 13, 16, 17, and 18 with VC or Cr 3 C 2 content of 1 wt% or less with respect to the amount of the binder phase have achieved excellent bending strength, It has been found that a bending strength higher than the kneading method can be realized.
[0029]
In addition, as a result of measurement with a PR thermocouple, the actual sample temperature in the electric current pressure sintering method performed in this example was found to be about 1380 ° C. This temperature is higher than the melting point 1320 ° C. of the eutectic composition of the WC-based cemented carbide, and it is considered that a liquid phase has appeared at least partially.
[0030]
(Example 2)
In order to perform solid-phase sintering, among the conditions of the electric current pressure sintering performed in Example 1, the maximum keep temperature was changed to 1000 ° C. and the holding time was changed to 60 minutes. Sample Nos. 2-1 to 2-9 were prepared using ˜1-9. Table 3 shows the results of measuring the average grain size and bending strength of WC using these sintered bodies in the same manner as in Example 1.
[0031]
[Table 3]
As a result, the sintered body produced by solid-phase sintering is a sintered body having a fine WC, but the bending strength is very low and the electric pressure sintering is performed with the liquid phase appearing and sintering. It can be seen that the characteristics are inferior to the results of the results.
[0033]
(Example 3)
Sample No. 3 which was sintered at 1000-1400 ° C. by changing only the maximum keep temperature among the energizing pressure sintering conditions of Example 1 using the raw material powder No. 1-9 used in Example 1. -1 to 3-7 were produced. The average grain size and bending strength of WC of these samples were measured in the same manner as in Example 1, and the specific gravity was measured by the Archimedes method. When the specific density of WC is 15.6 g / cm 3 , the specific gravity of Co is 8.9 g / cm 3 and the specific gravity of Cr 3 C 2 is 6.7 g / cm 3 , the theoretical density of the alloy of this composition is calculated to be 14.5 g /
[0034]
[Table 4]
Table 4 shows that a dense alloy having a theoretical density ratio exceeding 98% achieves an excellent bending strength. It was also found that the sintering temperature is preferably in the range of 1100 ° C. to 1350 ° C. from the viewpoint of the WC grain size and bending strength.
[0036]
Example 4
Using the WC powder and Co powder used in Example 1, the composition shown in Table 5 was used, and Sample No. was used under the same two conditions as in Example 1 (only the maximum keep temperature of the current pressing method was changed to 1250 ° C). 4-1 to 4-10 were produced. The theoretical density ratio of these samples was determined in the same manner as in Example 3. Further, these sintered bodies were subjected to surface grinding, mirror polishing, and Hv hardness was measured with a 50 kg load using a diamond Vickers indenter. These results are listed in Table 5.
[0037]
[Table 5]
From the results shown in Table 5, it can be seen that according to the current pressure sintering method, a hard alloy having a binder phase of 2 wt% or less can be densely sintered and an alloy having a high Hv hardness can be produced.
[0039]
(Example 5)
Prepare two types of powder containing WC as the hard phase, 10 wt% Co as the binder phase and 2 wt% Ni and WC particle size, and powder with a large WC particle size in the graphite mold (average particle size 2.5μm ) Was pressed into a layer and filled so that the lower layer and the small powder (average particle size of 0.25 μm) became the upper layer. Then, while applying a pressure of 41 MPa from the top and bottom, a current was passed through the graphite mold so that the heating rate was 300 ° C / min. When the temperature reached 1130 ° C, the pressure was kept for 6 minutes, and cooling was performed at 100 ° C / min. By doing so, a hard alloy was produced.
[0040]
The obtained disk-shaped sintered body having a diameter of 30 mm and a thickness of 8 mm was subjected to surface grinding with a # 250 grindstone, mirror-polished, and observed with an optical microscope. As a result, the average particle diameter of the WC in the upper layer was as small as 0.30 μm, and the average particle diameter of the WC in the lower layer was as large as about 3 μm.
[0041]
Moreover, composition analysis was performed by EPMA, but the movement of Co and Ni elements between each layer was relatively small, and the diffusion of the components between the layers, which was problematic in the sintered body by the conventional manufacturing method, was suppressed. .
[0042]
Since the WC-based cemented carbide has a higher hardness as the WC particle size is smaller and a higher toughness as the WC particle size is larger, the sintered body of this structure is excellent in wear resistance on the upper side and excellent in toughness on the lower side. It is a material that can satisfy both characteristics that are normally contradictory.
[0043]
(Example 6)
Prepare a WC with an average particle size of 0.25 μm as the hard phase, a powder containing 12 wt% Co and a powder containing 2 wt% Co as the binder phase, and arrange them so that the powder containing 2 wt% Co becomes the upper layer. Pressed into layers and filled into a graphite mold. Then, while applying a pressure of 60 MPa from the top and bottom, a current was passed through the graphite mold so that the heating rate would be 100 ° C / min. When the temperature reached 1250 ° C, the temperature was kept for 10 minutes and cooled at a rate of 200 ° C / min. By doing so, a hard alloy was produced.
[0044]
The obtained disk-shaped sintered body having a diameter of 30 mm and a thickness of 8 mm was subjected to surface grinding with a # 250 grindstone, mirror-polished, and observed with an optical microscope. As a result, in both the upper layer and the lower layer, the average particle diameter of WC was as small as 0.30 μm, the Hv hardness in the upper layer was 25 GPa, and the Hv hardness in the lower layer was 18.5 GPa.
[0045]
Further, the composition analysis was conducted by EPMA. However, the movement of Co element between the layers was relatively small, and the diffusion of the components between the layers, which was problematic in the sintered body by the conventional manufacturing method, was suppressed.
[0046]
The WC-Co cemented carbide has better wear resistance as the Co content is lower, and the toughness becomes higher as the Co content is higher. Therefore, the sintered body of this structure has excellent wear resistance on the upper side. Since it is excellent in toughness on the side, it is a material that can satisfy both of the conflicting properties.
[0047]
(Example 7)
Mixed powder A containing 2.0 wt% of WC powder with an average particle diameter of 0.25 μm and Co powder with an average particle diameter of 1 μm, and mixed powder containing 12 wt% of WC powder with an average particle diameter of 2.5 μm and Co powder with an average particle diameter of 1 μm B was prepared, and these two powders were blended to prepare five types of powder Nos. 5-1 to 5-5 as shown in Table 6.
[0048]
[Table 6]
These powders were sequentially filled into a graphite mold so that No. 5-1 was on the upper side and No. 5-5 was on the lower side. Then, while applying pressure from above and below, current is passed through the graphite mold so that the heating rate is 150 ° C / min. When 1130 ° C is reached, keep for 3 minutes and cool at a rate of 200 ° C / min. A hard alloy was prepared by
[0050]
A cross-section of the obtained disk-shaped sintered body having a diameter of 30 mm and a thickness of 10 mm was subjected to surface grinding with a # 250 grindstone, mirror-polished, and observed with an optical microscope. As a result, the average particle size of the WC in the upper layer is as small as 0.30 μm, the average particle size of the WC in the lower layer is as large as about 3 μm, and the WC particle size in the intermediate layer is as small as about 0.3 μm. It was confirmed that the structure was a mixture of WC, approximately 3 μm, and coarse WC.
[0051]
In addition, composition analysis was performed by EPMA, but the movement of Co element between each layer was relatively small, the Co layer in the upper layer had a small amount of Co, and the lower layer had a large Co amount. Diffusion of components between layers, which was problematic in the sintered body by the manufacturing method, was suppressed.
[0052]
The WC-Co cemented carbide has a smaller WC particle size, and the lower the Co content, the higher the hardness and the lower the toughness. The larger the WC particle size, the higher the Co content, the lower the hardness and the higher the toughness. Become. For this reason, the sintered body of this structure is excellent in abrasion resistance on the upper side and excellent in toughness on the lower side, and is a material that can satisfy both characteristics that are normally contradictory.
[0053]
(Example 8)
As shown in FIG. 2, and the average particle size 0.25μm of WC powder and the average particle size mixed-powder 1 containing 20 wt% of Co powder of 1μm placed on the
[0054]
When the cross-section of the disk-shaped sintered body having a diameter of 50 mm and a thickness of 20 mm was ground with a # 250 grindstone and then mirror-polished and observed with an optical microscope, the average WC average particle size of the upper layer was 0.30 μm. The average particle size of the WC in the lower layer was as large as about 3 μm.
[0055]
Further, the composition analysis was conducted by EPMA. However, the movement of Co element between the layers was relatively small, and the diffusion of the components between the layers, which was problematic in the sintered body by the conventional manufacturing method, was suppressed.
[0056]
The sintered body of this structure has high wear resistance because the upper layer is made of WC with a small particle size, and the lower layer is made of steel, so that high strength and high toughness can be obtained. It is a material that can achieve both properties.
[0057]
Example 9
In the same manner as in Example 7, using two types of powders A and B having different WC particle sizes and Co amounts, five types of powders having different mixing ratios were laminated on a steel substrate. It was. Then, while applying a pressure of 41 MPa from the top and bottom, a current was passed through the graphite mold so that the temperature rose at a rate of 190 ° C / min. When the temperature reached 1130 ° C, it was kept for 6 minutes and cooled at a rate of about 100 ° C / min. The hard alloy was joined on the steel by
[0058]
The cross-section of the disk-shaped sintered body having a diameter of 50 mm and a thickness of 30 mm was ground with a # 250 grindstone, then mirror-polished and observed with an optical microscope. The average WC average particle size of the upper layer was 0.30 μm. The average particle size of the WC in the lower layer was as large as about 3 μm.
[0059]
In addition, composition analysis was performed by EPMA, but the Co content increased in order from the upper layer to the lower layer, and the movement of Co element between each layer was relatively small. It was confirmed that the diffusion of the components between the problematic layers was suppressed.
[0060]
The WC-Co cemented carbide has a smaller WC particle size, and the lower the Co content, the higher the hardness and the lower the toughness. The larger the WC particle size, the higher the Co content, the lower the hardness and the higher the toughness. Become. From this, the sintered body of this example has high wear resistance because the upper layer is made of WC with a small particle size and a small amount of Co, and the lower layer is made of WC with a large particle size and a large amount of Co. Since it is a cemented carbide alloy and a steel layer, it can obtain high strength and high toughness, and it is a material that can achieve both characteristics that are normally contradictory.
[0061]
【The invention's effect】
As described above, the hard alloy of the present invention has an average particle diameter of WC finer than 0.5 μm, and therefore can be used for cutting, wear-resistant tools and the like that require high hardness. In particular, by using an alloy having a different composition in the thickness direction, it is possible to obtain an alloy having characteristics that are contradictory on one side and the other side of the alloy.
[0062]
Further, the production method of the present invention is an optimal method for producing the hard alloy of the present invention, and can be sintered in a short time, thus contributing to cost reduction.
[Brief description of the drawings]
FIG. 1 is a scanning micrograph showing the structure of a hard alloy of the present invention.
FIG. 2 is a schematic view of an apparatus for producing the hard alloy of the present invention.
[Explanation of symbols]
1
Claims (13)
前記ＷＣの平均粒径が0.4 μ mより小さく、
Ｃｒ、Ｖ、Ｃｒの炭化物、Ｖの炭化物を合計で結合相量の１wt％以下しか含まないことを特徴とする高硬度硬質合金。In a hard alloy comprising a hard phase composed of WC and a binder phase composed of an iron group metal,
The average particle size of the WC is less than 0.4 mu m,
A high-hardness hard alloy characterized by containing a total of Cr, V, Cr carbide, and V carbide in an amount of 1 wt% or less of the amount of the binder phase.
硬質合金の上部層におけるＷＣの平均粒径が0.4 μ mより小さく、下部層におけるそれが0.4 μ m以上であるように厚さ方向にＷＣの平均粒径が変化していることを特徴とする請求項１記載の高硬度硬質合金。 When the hard alloy is layered and has a thickness between the upper and lower layers,
The average particle size of the WC in the upper layer of the hard alloy is less than 0.4 mu m, wherein the average particle size of the WC in the thickness direction so that in the lower layer is at least 0.4 mu m is changed The high hardness hard alloy according to claim 1.
硬質合金の上部層における結合相量が0.1〜２wt％の範囲にあり、下部層におけるそれが同範囲にないように厚さ方向に組成が変化していることを特徴とする請求項１記載の高硬度硬質合金。 When the hard alloy is layered and has a thickness between the upper and lower layers,
2. The amount of binder phase in the upper layer of the hard alloy is in the range of 0.1 to 2 wt%, and the composition is changed in the thickness direction so that it is not in the same range in the lower layer . High hardness hard alloy.
この混合粉末から構成される原料部材を通電加熱装置に配置する工程と、
この原料部材を1100℃〜1350℃、５〜200MPaで通電加圧焼結する工程とを具え、
前記原料粉末を混合する工程において、ＷＣは、平均粒径が 0.5 μ m より小さい粉末 ( 但し、 0.4 μ m 以上を除く ) を用いることを特徴とする高硬度硬質合金の製造方法。Hard phase consisting of WC, a step of mixing each raw material powder of the binder phase and binder phase content of 1 wt% or less of the grain growth inhibiting material made of an iron group metal,
Arranging the raw material member composed of the mixed powder in an electric heating device;
The material member comprises a step of applying current and pressure sintering at 1100 ° C. to 1350 ° C. and 5 to 200 MPa ,
The raw material powder in the step of mixing, WC has an average particle diameter of 0.5 mu m is smaller than powder (however, 0.4 mu excluding more than m) method for producing a high hardness hard alloy, which comprises using a.
これら複数種の混合粉末を積層して硬質相粒径を厚さ方向に変化させた原料部材を通電加圧焼結することを特徴とする請求項８記載の高硬度硬質合金の製造方法。Prepare multiple types of mixed powders with different hard phase particle sizes in the process of mixing raw material powders,
The method for producing a high hardness hard alloy according to claim 8, wherein a raw material member obtained by laminating a plurality of kinds of mixed powders and changing the hard phase particle size in the thickness direction is subjected to electric current pressure sintering.
この複数種の混合粉末を積層して組成を厚さ方向に変化させた原料部材を通電加圧焼結することを特徴とする請求項８記載の高硬度硬質合金の製造方法。Prepare multiple types of mixed powders with different amounts of binder phase in the raw material powder mixing step,
The method for producing a high hardness hard alloy according to claim 8, wherein the raw material member having the composition changed in the thickness direction by laminating a plurality of kinds of mixed powders is subjected to current-pressure sintering.
通電加圧装置には、原料部材と基体との複合体を配置し、
この複合体を通電加圧焼結して、基体に原料部材の焼結体を焼結接合することを特徴とする請求項８記載の高硬度硬質合金の製造方法。After mixing the raw material powder, comprising a step of arranging a raw material member made of the mixed powder on a base of metal material,
In the energizing and pressing apparatus, a composite of the raw material member and the substrate is arranged,
9. The method for producing a high hardness hard alloy according to claim 8, wherein the composite is sintered under current and pressure, and the sintered body of the raw material member is sintered and joined to the base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28307496A JP4177468B2 (en) | 1996-10-04 | 1996-10-04 | High hardness hard alloy and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28307496A JP4177468B2 (en) | 1996-10-04 | 1996-10-04 | High hardness hard alloy and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10110235A JPH10110235A (en) | 1998-04-28 |
| JP4177468B2 true JP4177468B2 (en) | 2008-11-05 |
Family
ID=17660879
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28307496A Expired - Fee Related JP4177468B2 (en) | 1996-10-04 | 1996-10-04 | High hardness hard alloy and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4177468B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE530516C2 (en) * | 2006-06-15 | 2008-06-24 | Sandvik Intellectual Property | Coated cemented carbide insert, method of making this and its use in milling cast iron |
| TWI347978B (en) | 2007-09-19 | 2011-09-01 | Ind Tech Res Inst | Ultra-hard composite material and method for manufacturing the same |
| JP6068830B2 (en) * | 2011-05-12 | 2017-01-25 | 株式会社タンガロイ | Cemented carbide and coated cemented carbide |
| CN103667844B (en) * | 2013-12-31 | 2015-06-24 | 株洲硬质合金集团有限公司 | Hard alloy for low-load high-speed punching precision mold and preparation method thereof |
| TWI641698B (en) * | 2017-12-12 | 2018-11-21 | 國立清華大學 | Cermets for magnetic sensors |
| JP7441418B2 (en) * | 2020-03-24 | 2024-03-01 | 三菱マテリアル株式会社 | WC-based cemented carbide cutting tools and surface-coated WC-based cemented carbide cutting tools with excellent plastic deformation resistance and fracture resistance |
-
1996
- 1996-10-04 JP JP28307496A patent/JP4177468B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10110235A (en) | 1998-04-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100219930B1 (en) | Superhard composite member and its production | |
| EP2462083B1 (en) | Tough coated hard particles consolidated in a tough matrix material | |
| KR100260368B1 (en) | Composite material and process for producing the same | |
| KR100391096B1 (en) | Ultra-Granular Composites and Manufacturing Method | |
| EP0773202B1 (en) | Composite material and method of manufacturing the same | |
| US6066191A (en) | Hard molybdenum alloy, wear resistant alloy and method for manufacturing the same | |
| CN105734390B (en) | A kind of preparation method for the polycrystalline cubic boron nitride compound material that high-entropy alloy combines | |
| JP2004292905A (en) | Compositionally graded sintered alloy and method of producing the same | |
| JP4274588B2 (en) | Manufacturing method of composite material | |
| JP6259978B2 (en) | Ni-based intermetallic compound sintered body and method for producing the same | |
| JP3916465B2 (en) | Molten metal member made of sintered alloy having excellent corrosion resistance and wear resistance against molten metal, method for producing the same, and machine structure member using the same | |
| JP4193958B2 (en) | Molten metal member having excellent corrosion resistance against molten metal and method for producing the same | |
| JP4177468B2 (en) | High hardness hard alloy and its manufacturing method | |
| US20050226691A1 (en) | Sintered body with high hardness for cutting cast iron and the method for producing same | |
| KR20090022634A (en) | Method for manufacturing polycrystalline diamond using amorphous bond | |
| JP4177467B2 (en) | High toughness hard alloy and manufacturing method thereof | |
| JP3837332B2 (en) | In-situ powder metallurgy manufacturing method for wear-resistant composite materials | |
| JPH10310840A (en) | Superhard composite member and its production | |
| JP4409067B2 (en) | Molten metal member having excellent corrosion resistance against molten metal and method for producing the same | |
| JP2627090B2 (en) | Bonded body of boride ceramics and metal-based structural member and bonding method | |
| JP4976626B2 (en) | Sintered alloy material, method for producing the same, and mechanical structural member using the same | |
| JPH11181540A (en) | Hyperfine-grained cemented carbide | |
| JPH10310839A (en) | Super hard composite member with high toughness, and its production | |
| JPH05302136A (en) | Whisker reinforced sintered hard alloy | |
| JP2023048855A (en) | Hard sintered body, method for producing hard sintered body, cutting tool, wear-resistant tool and high-temperature member |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| RD04 | Notification of resignation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7424 Effective date: 20051025 |
|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20060308 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060913 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20061113 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20080818 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20080822 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110829 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120829 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130829 Year of fee payment: 5 |
|
| LAPS | Cancellation because of no payment of annual fees |