JP2004291038A

JP2004291038A - Bonding method for cemented carbide member and diamond member, bonding structure, cutting blade chip for drilling tool, cutting blade member, and drilling tool

Info

Publication number: JP2004291038A
Application number: JP2003088131A
Authority: JP
Inventors: Kazuo Yamamoto; 和男山本; Chuichi Ohashi; 忠一大橋; Eko Wardoyo Akhmadi; アフマディ・エコ・ワルドヨ
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2003-03-27
Filing date: 2003-03-27
Publication date: 2004-10-21

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bonding method for bonding a member made of cemented carbide and a member made of diamond having high bonding strength and low risk of occurrence of fatigue fracture , a bonding structure, a cutting blade chip for drilling tool, a cutting blade member, and a drilling tool. <P>SOLUTION: The cutting blade chip used for the cutting blade of the drilling tool has a structure comprising a cutting blade body part 11 made of the cemented carbide (the cemented carbide member), the member 12 made of diamond supported by the cutting blade body part 11, and a metal layer 13 that is arranged between the cutting blade body part 11 and the diamond member 12 and diffusion-bonded with them respectively. The metal layer 13 is composed of one kind of metal among V, Nb and Ta, or an alloy made from two or more kinds among these metals. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、超硬合金製部材とダイヤモンド製部材との接合方法、接合構造と、坑井の掘削に用いられる掘削工具の切刃片、切刃部材、及び掘削工具に関する。
【０００２】
【従来の技術】
油井その他の坑井の掘削に用いられる掘削工具としては、合金鋼製工具本体の先端面に、複数の炭化タングステン基超硬合金製ポスト（以下、超硬ポストという）が所定の配列でろう付けや焼きばめなどの手段で固着され、この超硬ポストの先方側面のそれぞれに、全体が超高圧焼結ダイヤモンド（以下、焼結ダイヤという）からなる切刃片が直接ろう付けされた構造の掘削工具が知られている。
この掘削工具は、工具本体をパイプの先端に取り付けて、工具本体に対してパイプを介して掘削方向への荷重を加えながら工具本体を回転させることで、工具本体に設けた切刃片によって掘削を行うものである。
【０００３】
ここで、ダイヤモンドは濡れ性が悪く、通常のろう材によるろう付けが困難であるので、この掘削工具では、例えばＣｕ（銅）：２０〜４０質量％、Ｔｉ（チタン）：０．５〜１０質量％を含有し、残りがＡｕ（金）と不可避不純物とからなる組成を有するＡｕ合金ろう材（融点は９４０°Ｃ）を用いて超硬ポストに対する切刃片のろう付けを行っている（例えば特許文献１参照）。
【０００４】
【特許文献１】
特開２０００−０００６８６号公報
【０００５】
【発明が解決しようとする課題】
ところで、近年は、掘削作業の省力化及び省エネ化、さらに低コスト化に対する要求が強い。例えば、石油等の採掘のための掘削作業では、一日の操業コストは５００〜２０００万円と非常に高額であることから、コスト低減のために、掘削速度を速めて掘削作業を短期間で終了させることが求められている。
掘削速度を速めるためには、工具本体に加える荷重を大きくしたり、工具本体の回転速度を速くすればよいが、近年は、パイプの交換作業、継ぎ足し作業を低減するため、従来よりも細長いパイプが用いられるようになってきており、パイプを介して工具本体に加える荷重をあまり大きくすることができないので、工具本体の回転速度を上げることで高速掘削を行っている。例えば、石油掘削の場合では、工具本体の回転数は従来７０〜１５０回転／分であったのに対して、近年は５００〜１０００回転／分と、一桁高い回転数で掘削を行っている。
【０００６】
しかし、このように工具本体の回転数が高くなると、掘削作業時に切刃に衝撃が加わる頻度が高まる。掘削工具において、超硬合金製の超硬ポストと焼結ダイヤからなる切刃片とは、上記のようにろう付けによって接合されており、その接合強度はあまり高くないので、このように切刃に衝撃が繰り返し加えられることで、比較的短時間でこれらの接合部に疲労破壊が生じて、切刃片が超硬ポストから剥がれてしまう可能性がある。また、あまり掘削速度を速くすると、掘削熱も大きくなるため、切刃片をろう付けしているろう材が融けて切刃片が超硬ポストから剥がれてしまう可能性がある。
このため、従来は、掘削速度をあまり速くすることができなかった。
【０００７】
本発明は、このような事情を鑑みてなされたものであって、接合強度がより高く、また疲労破壊が生じにくい超硬合金製部材とダイヤモンド製部材との接合方法、接合構造、掘削工具の切刃片、切刃部材、及び掘削工具を提供することを目的としている。
【０００８】
【課題を解決するための手段】
本発明にかかる超硬合金製部材とダイヤモンド製部材との接合方法は、超硬合金製部材とダイヤモンド製部材との間に、Ｖ（バナジウム）、Ｎｂ（二オブ）、Ｔａ（タンタル）のうちのいずれか一種の金属と不可避不純物とからなる金属箔、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなる金属箔を挟み込み、前記超硬合金製部材及び前記ダイヤモンド製部材を、それぞれ前記金属箔と拡散接合することを特徴としている。
【０００９】
超硬合金製部材及びダイヤモンド製部材と金属箔との拡散接合は、超硬合金製部材とダイヤモンド製部材との間に金属箔を挟み込んだ状態で、例えば５〜６ＧＰａの超高圧下で、１４００〜１５５０°Ｃの超高温の熱処理を施すことで行われる。
ここで、金属箔を構成するＶ、Ｎｂ、Ｔａは、いずれもダイヤモンドの焼結に用いられる触媒金属ではないので、上記の熱処理を行っても金属箔の一部のみが超硬合金製部材及びダイヤモンド製部材に拡散されることとなり、金属箔の大部分はそのまま超硬合金製部材とダイヤモンド製部材との間に残留して、これらの間に金属層を形成する。また、金属箔を構成する金属または合金は、前記のように触媒金属ではないため、ダイヤモンド製部材において金属箔との接合部分近傍にのみ拡散することとなり、ダイヤモンド製部材の物性に悪影響を与えない。
【００１０】
このように拡散接合を行うことで、ダイヤモンド製部材において金属箔との接合部分近傍には、金属箔の成分が拡散された拡散層が形成されることとなり、ダイヤモンド製部材と金属箔とが強固に接合される。
また、超硬合金製部材においても、金属箔との接合部分近傍には、金属箔の成分が拡散された拡散層が形成されるので、超硬合金製部材と金属箔とが強固に接合される。
そして、この金属箔を構成する金属または合金は延性に富んでいるので、この金属箔によって超硬合金製部材とダイヤモンド製部材との接合部に加わる衝撃が吸収されることとなって接合部に疲労破壊が生じにくい。
さらに、金属箔を構成する金属または合金は、いずれも従来用いられているろう材よりも融点が高いので、この接合方法によって得られる接合構造は、従来のろう付けによる接合構造よりも高い耐熱性を有している。
【００１１】
ここで、超硬合金製部材とダイヤモンド製部材とは熱収縮率が異なるが、これらの間には金属層が形成されており、この金属層が応力緩衝材として作用するので、上記熱処理後に常温常圧下に戻す際に、超硬合金製部材及びダイヤモンド製部材内に蓄えられた応力が金属層によって吸収されることとなり、ダイヤモンド製部材に応力が集中しにくくなってダイヤモンド製部材にクラック等が生じにくく、また超硬合金製部材とダイヤモンド製部材との剥離が生じにくい。
【００１２】
本発明にかかる超硬合金製部材とダイヤモンド製部材との接合構造は、超硬合金製部材とダイヤモンド製部材との間に、Ｖ、Ｎｂ、Ｔａのうちのいずれか一種の金属と不可避不純物とからなる金属層、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなる金属層が設けられ、前記超硬合金製部材及び前記ダイヤモンド製部材が、それぞれ前記金属層と拡散接合されていることを特徴としている。
この超硬合金製部材とダイヤモンド製部材との接合構造では、接合強度が高く、また金属層が延性に富んだ金属またはその合金によって構成されていてこの金属層によって接合部に加わる衝撃が吸収されるので、従来のろう付けによる接合構造に比べて、接合部に疲労破壊が生じにくい。
また、この接合構造では、超硬合金製部材とダイヤモンド製部材とを接合する金属層が、従来用いられているろう材よりも融点の高い金属またはその合金によって構成されているので、従来の接合構造よりも高い耐熱性を有している。
【００１３】
本発明にかかる掘削工具の切刃片は、掘削工具の工具本体の先端面に設けられるポストに対して装着されて前記掘削工具における切刃を構成する切刃片であって、前記ポストとの接合部を構成する超硬合金製の切刃基体と、該切刃基体に支持されるダイヤモンド製部材とを有し、前記切刃基体と前記ダイヤモンド製部材との間には、Ｖ、Ｎｂ、Ｔａのうちのいずれか一種の金属と不可避不純物とからなる金属層、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなる金属層が設けられ、前記切刃基体及び前記ダイヤモンド製部材が、それぞれ前記金属層と拡散接合されていることを特徴としている。
【００１４】
このように構成される掘削工具の切刃片においては、切刃基体とダイヤモンド製部材との間に金属層が設けられ、切刃基体とダイヤモンド製部材とが金属層に対して拡散接合されているので、切刃基体に対するダイヤモンド製部材の接合強度が著しく高い。
さらに、この金属層を構成する金属またはその合金は、延性に富んだ金属であるので、この金属層によって超硬合金製部材とダイヤモンド製部材との接合部に加わる衝撃が吸収されることとなって接合部に疲労破壊が生じにくい。
また、金属層は高融点金属または高融点金属の合金からなるので、接合構造の耐熱性が高い。
【００１５】
この掘削工具の切刃片において、ダイヤモンド製部材を、結合材として炭酸マグネシウム（以下、ＭｇＣＯ_３で示す）を用いた高耐熱性焼結ダイヤモンドによって構成してもよい。
ここで、高耐熱性焼結ダイヤモンドとは、ダイヤモンド粉を、結合材として例えばＭｇＣＯ_３を用いて７〜８ＧＰａの超高圧下で、１８００〜２４００°Ｃの超高温の熱処理を施して焼結したものである。
この場合には、ダイヤモンド製部材がより耐熱性の優れた高耐熱性ダイヤモンドによって構成されるので、より高負荷条件での掘削を行うことができる。
【００１６】
本発明にかかる切刃部材は、掘削工具の工具本体の先端面に設けられる切刃部材であって、前記工具本体に装着される超硬合金製のポストと、該ポストに対して装着されて前記掘削工具における切刃を構成するダイヤモンド製の切刃片とを有し、前記ポストと前記切刃片との間には、Ｖ、Ｎｂ、Ｔａのうちのいずれか一種の金属と不可避不純物とからなる金属層、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなる金属層が設けられ、前記ポスト及び前記切刃片が、それぞれ前記金属層と拡散接合されていることを特徴としている。
このように構成される掘削工具の切刃部材においては、超硬合金製のポストとダイヤモンド製の切刃片との接合強度が著しく高く、また接合部に疲労破壊が生じにくく、接合構造の耐熱性も高い。
【００１７】
本発明にかかる切刃部材は、掘削工具の工具本体の先端面に設けられる切刃部材であって、前記工具本体に装着されるポストと、該ポストに対して装着されて前記掘削工具における切刃を構成する切刃片とを有しており、該切刃片が、請求項３または４に記載の切刃片とされていることを特徴としている。
このように構成される掘削工具の切刃部材においては、超硬合金製の切刃基体に対するダイヤモンド製部材の接合強度が著しく高く、また接合部に疲労破壊が生じにくく、接合構造の耐熱性も高い切刃片が切刃として用いられる。
【００１８】
本発明にかかる掘削工具は、工具本体の先端面に、切刃片をポストに装着してなる切刃部材が装着される掘削工具であって、前記切刃片として請求項３または４に記載の切刃片を用いるか、もしくは前記切刃部材として請求項５または６に記載の切刃部材を用いることを特徴としている。
このように構成される掘削工具においては、超硬合金製の切刃基体に対するダイヤモンド製部材の接合強度が著しく高く、また接合部に疲労破壊が生じにくく、接合構造の耐熱性も高い切刃片、または超硬合金製のポストとダイヤモンド製の切刃片との接合強度が著しく高く、また接合部に疲労破壊が生じにくく、接合構造の耐熱性も高い切刃部材を用いて掘削が行われる。
【００１９】
【発明の実施の形態】
以下、本発明の一実施形態について、図を用いて説明する。本実施の形態では、本発明にかかる超硬合金製部材とダイヤモンド製部材との接合方法、接合構造を、掘削工具の切刃片に適用している。
ここで、図１は、本実施の形態にかかる掘削工具の構成を概略的に示す斜視図であり、図２は本実施の形態にかかる掘削工具を構成する切刃部材の構成を概略的に示す側面図、図３は本実施の形態にかかる切刃片の構成を概略的に示す斜視図、図４は本実施の形態にかかる切刃片の構造を示す断面図である。
【００２０】
本実施形態にかかる掘削工具１は、ＪＩＳ・ＳＣＨ４１５に規定される合金鋼等からなる略円盤形状の工具本体２と、工具本体２の先端面に所定の配列で複数設けられる切刃部材３とを有している。切刃部材３は、工具本体２に対して、ろう付けや焼きばめなどの手段で装着されるものである。
切刃部材３は、柱状をなす超硬合金製の超硬ポスト６と、この超硬ポスト６において掘削方向を向く側面にろう付け等によって装着される切刃片７とを有している。本実施の形態では、超硬ポスト６は、一般的な炭化タングステン基超硬合金によって構成されている。
【００２１】
切刃片７は、超硬ポスト６との接合部を構成する超硬合金製の切刃基体１１と、切刃基体１１に支持されるダイヤモンド製部材１２とを有しており、これら切刃基体１１とダイヤモンド製部材１２との間には金属層１３が設けられており、切刃基体１１及びダイヤモンド製部材１２は、それぞれ金属層１３に対して拡散接合されている。
【００２２】
切刃基体１１は、略円板形状に形成されており、その一面は超硬ポスト６にろう付けされるろう付け面とされ、またこの一面に対向する他面側（すなわち掘削方向を向く面側）には切り欠き状の凹部が形成されており、この凹部がダイヤモンド製部材１２を装着するための取付座１１ａとされている。この取付座１１ａは、ダイヤモンド製部材１２の外形と同形状とされており、切刃片７において掘削作業時に磨耗が生じやすい領域に設けられている。本実施の形態では、取付座１１ａは、平面視扇型とされている。
また、切刃基体１１は、Ｃｏ（コバルト）を結合材として用いた炭化タングステン基超硬合金、すなわち一般的な超硬合金によって構成されている。本実施の形態では、切刃基体１１は、結合材であるＣｏを１０質量％含有し、残りがＷＣ（タングステンカーバイド）と不可避不純物とされた超硬合金によって構成している。超硬合金は高強度で高靭性を有しているので、超高合金製の切刃基体１１は、切刃片７において掘削作業時に加わる熱的機械的衝撃を吸収する衝撃吸収体として作用する。
【００２３】
ダイヤモンド製部材１２は、切刃片７において掘削作業時に摩耗が生じやすい領域に設けられるものである。本実施の形態では、切刃片７の前面に占めるダイヤモンド製部材１２の割合を、２５〜６０面積％としている。
ここで、ダイヤモンド製部材１２は、通常の焼結ダイヤモンド単体や、より優れた耐熱性を有する高耐熱性焼結ダイヤモンド単体によって構成されるほか、通常の焼結ダイヤモンドと高耐熱性焼結ダイヤモンドとの複合体によって構成してもよい。本実施の形態では、ダイヤモンド製部材１２は、扇型の耐熱性焼結ダイヤモンド単体によって構成されている。
【００２４】
切刃基体１１とダイヤモンド製部材１２との間に設けられる金属層１３は、Ｖ、Ｎｂ、Ｔａのうちのいずれか一種の金属と不可避不純物、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなるものである。本実施の形態では、金属層１３をＴａからなる箔によって構成しており、その厚さＤは、０．０２〜０．１ｍｍとされている。
ここで、Ｖ、Ｎｂ、Ｔａはいずれも高融点金属であり（Ｖの融点は１７００°Ｃ、Ｎｂの融点は２４６７°Ｃ、Ｔａの融点は２８５０°Ｃ）、これらの合金の融点も同様に高い。また、Ｖ、Ｎｂ、Ｔａは、いずれも高融点金属の中では延性に富んだ金属であり、これらの合金も同様に延性に富んでいる。
【００２５】
このように構成される切刃片７は、次のようにして作成される。
まず、切刃基体１１及びダイヤモンド製部材１２をそれぞれ所望の形状で製造する。
切刃基体１１は、通常の超硬合金製品と同様にして製造される。例えば、超硬合金の原料粉末を成形、焼結することによって円板型超硬合金チップを形成し、この超硬合金チップの一面側に切削加工等を施して取付座１１ａを形成するか、超硬合金の原料粉末を取付座１１ａを有する円板形状に成形して焼結することによって得られる。
【００２６】
ダイヤモンド製部材１２は、原料粉末として、平均粒径１０μｍ、純度９９．９％以上のダイヤモンド粉末と、平均粒径１０μｍ、純度９５％以上のＭｇＣＯ_３粉末を用いて作製される。
まず、ＭｇＣＯ_３粉末を、１００ＭＰａの圧力でプレス成形して所望の形状の圧粉体とする。続いて、この圧粉体をＴａ（タンタル）製のカプセル内に装入し、ついでこのカプセル内の圧粉体上にダイヤモンド粉末を充填する。
この状態で、カプセルをベルト型超高圧焼結装置（通常の焼結ダイヤ製造に用いられる超硬圧焼結装置）に装填して超高圧焼結を行って、４．０重量％のＭｇＣＯ_３を含有した焼結ダイヤモンドのブロックを得る。
本実施の形態では、上記の超高圧焼結は、７．７Ｇｐａの圧力を加えた状態で２２５０°Ｃまで加熱して３０分間保持することで行っている。
そして、この焼結ダイヤモンドのブロックにダイヤモンド砥石による研磨を施して粗整形したのちに、さらにレーザー加工によって所望の形状のダイヤモンド片を切り出すことで、ダイヤモンド製部材１２を得る。
【００２７】
続いて、上記のようにして得た切刃基体１１とダイヤモンド製部材１２との間に、Ｖ、Ｎｂ、Ｔａのうちのいずれか一種の金属と不可避不純物とからなる金属箔、もしくはこれらのうちの二種以上の金属の合金と不可避不純物とからなる金属箔（厚さ０．０２〜０．１ｍｍ）を挟みこんだ状態にして、切刃基体１１の取付座１１ａにダイヤモンド製部材１２を嵌め込む。
さらに、このように仮組みした切刃基体１１、金属箔、ダイヤモンド製部材１２とを、ベルト型超高圧焼結装置に装填し、超高温高圧の熱処理を行って、これらの部材を接合して一体化させ、本発明にかかる切刃片７を得る。本実施の形態では、上記の超高温高圧の熱処理は、５．５ＧＰａの圧力を加えた状態で１５００°Ｃまで加熱して３０分間保持することで行っている。
【００２８】
この熱処理により、金属箔の成分が切刃基体１１及びダイヤモンド製部材１２にそれぞれ拡散し、切刃基体１１及びダイヤモンド製部材１２において金属箔との界面近傍には、金属箔を構成する成分が拡散してなる超高圧加熱溶融拡散層Ｓ１、Ｓ２が形成される。
ここで、金属箔を構成するＶ、Ｎｂ、Ｔａは、いずれもダイヤモンドの焼結に用いられる触媒金属ではないので、上記の熱処理を行っても金属箔の一部のみが切刃基体１１及びダイヤモンド製部材１２に拡散されることとなり、金属箔の大部分はそのまま切刃基体１１とダイヤモンド製部材１２との間に残留して、これらの間に金属層１３を形成する。また、金属箔を構成する金属またはその合金は、前記のように触媒金属ではないため、ダイヤモンド製部材１２において金属箔との接合部分近傍にのみ拡散することとなり、ダイヤモンド製部材１２の物性に悪影響を与えない。
【００２９】
超高圧加熱溶融拡散層Ｓ１、Ｓ２のうち、切刃基体１１に形成される超高圧加熱溶融拡散層Ｓ１は、金属層１３との接合面から０．１〜０．５ｍｍの深さに亘って形成され、ダイヤモンド製部材１２に形成される超高圧加熱溶融拡散層Ｓ２は、金属層１３との接合面から０．０１〜０．１ｍｍの深さに亘って形成される。
この超高圧加熱溶融拡散層の存在によって、切刃基体１１及びダイヤモンド製部材１２は、それぞれ金属層１３に対して著しく強固に接合される。
なお、この超高圧加熱溶融拡散層Ｓ１、Ｓ２の様子及びその形成範囲は、金属顕微鏡を用いて組織観察を行うことで調べることができる。
【００３０】
ここで、切刃基体１１とダイヤモンド製部材１２とは熱収縮率が異なるが、これらの間には金属層１３が形成されており、この金属層１３が応力緩衝材として作用するので、上記熱処理後に常温常圧下に戻す際に、切刃基体１１及びダイヤモンド製部材１２内に蓄えられた応力が金属層１３によって吸収されることとなり、ダイヤモンド製部材１２に応力が集中しにくくなってダイヤモンド製部材１２にクラック等が生じにくく、また切刃基体１１とダイヤモンド製部材１２との剥離が生じにくい。
【００３１】
このようにして得られた切刃片７は、超硬ポスト６にろう付けされて切刃部材３とされる。そして、この切刃部材３を工具本体２に装着することで、掘削工具１を得る。
【００３２】
このように構成される掘削工具１は、従来の掘削工具と同様にして掘削作業に用いられる。
この掘削工具１では、切刃片７において切刃基体１１とダイヤモンド製部材１２とが強固に接合されている。また、切刃基体１１とダイヤモンド製部材１２との間に設けられる金属層１３を構成する金属またはその合金は、延性に富んているので、この金属層１３によって切刃基体１１とダイヤモンド製部材１２との接合部に加わる衝撃が吸収されることとなって接合部に疲労破壊が生じにくい。
このため、この掘削工具１では、高速掘削等の高負荷条件下での掘削を行うことが可能となる。
そして、金属層１３を構成する金属または合金の融点は、従来のろう材の融点に比べて十分に高く、切刃基体１１とダイヤモンド製部材１２との接合構造の耐熱性が従来に比べて向上しているので、従来の掘削工具ではろう材の耐熱性の問題のために不可能であった高速度で掘削を行うことができる。
【００３３】
ここで、高速掘削を行うと、切刃片７に極めて高い熱的機械的衝撃が付加されるようになる。切刃片７として用いられるダイヤモンド製部材１２自体は著しく硬質であるが、その反面、脆いものであるために、強い衝撃を受けると微小欠けが生じやすい。ダイヤモンド部材１２では、微小欠けが生じることによって磨耗の進行が著しく促進されることとなり、この結果比較的短時間で使用寿命に至ることとなる。
【００３４】
本発明者らの研究により、掘削工具１における切刃部材３の装着位置の関係から、切刃部材３を構成する切刃片７には、掘削による摩耗が切刃片前面全体に亘って進行するのではなく、切刃片前面の特定個所が局部的に摩耗し、残りの部分の摩耗はこの局部的な摩耗に追従する僅かなものに過ぎないこと、並びにこの局所的な摩耗が生じる領域の大きさが切刃片前面の２５面積％以下であることが判明した。
そこで、本実施の形態では、耐磨耗性に優れるダイヤモンド製部材１２を、切刃片７において局所的な摩耗が生じる領域に位置させて設け、他の部分は衝撃吸収性能を有する超高合金製の切刃基体１１によって構成した。これにより、切刃片７の局所的な摩耗を生じにくくしつつ、掘削時に切刃片７に加わる熱的機械的衝撃を切刃基体１１によって吸収させて衝撃によるダイヤモンド製部材１２の微小欠けを生じにくくすることができ、切刃片７の寿命が向上した。
【００３５】
ここで、切刃片前面に占めるダイヤモンド製部材１２の割合が２５面積％未満になると、超硬合金製の切刃基体１１が直接掘削に関与するようになり、切刃基体１１の摩耗が進行してしまう。一方、前記割合が６０面積％を超えると、相対的に衝撃吸収部として作用する切刃基体１１の占める割合が少なくなりすぎて、高速回転操業で発生するきわめて高い熱的機械的衝撃を十分に吸収することができず、この結果特にダイヤモンド製部材１２における微小欠けの発生が急激に増加するようになる。このため、切刃片７の前面に占めるダイヤモンド製部材１２の割合は、２５〜６０面積％とすることが好ましく、３０〜４５面積％とすることがより好ましい。
【００３６】
なお、上記実施の形態では、切刃片７を、扇形の取付座１１ａを有する切刃基体１１と、耐熱性焼結ダイヤモンドからなる扇形のダイヤモンド製部材１２とを有する構成としたが、これに限られることなく、切刃片７を構成する部材は他の任意形状とすることができる。
例えば、図５（ａ）に示すように、切刃片７は、単に板状の切刃基体１１と板状のダイヤモンド製部材１２とを金属層１３を介して接合した構成としてもよい。さらに、図５（ｂ）に示すように、ダイヤモンド製部材１２は、その一部を高耐熱焼結ダイヤモンドからなる高耐熱ダイヤ部１２ａとし、残りの部分を通常の焼結ダイヤモンドからなる焼結ダイヤ部１２ｂとした構成としてもよく、図５（ｃ）に示すように、焼結ダイヤ部１２ｂ中に高耐熱ダイヤ部１２ａを埋め込んだ構成としてもよい。
【００３７】
また、上記実施の形態では、本発明にかかる超硬合金製部材とダイヤモンド製部材との接合方法及び接合構造を、掘削工具１の切刃片７に適用した例を示したが、これに限られることなく、例えば、図６に示すように、切刃片として全体が通常の焼結ダイヤモンドまたは高耐熱ダイヤモンドによって構成される切刃片７ａを用いる場合には、本発明を、切刃部材３における超硬ポスト６と切刃片７ａとの接合に適用してもよい。
【００３８】
また、本発明にかかる超硬合金製部材とダイヤモンド製部材との接合方法及び接合構造は、上記の例にのみ適用範囲が限定されるものではなく、超硬合金製部材とダイヤモンド製部材とが接合されるものであれば、任意のものに適用することができる。
【００３９】
【発明の効果】
本発明にかかる超硬合金製部材とダイヤモンド製部材との接合方法、接合構造によれば、超硬合金製部材及びダイヤモンド製部材とが、これらの間に設けられた前記組成の金属層に拡散接合されるので、従来のろう付けによる接合構造に比べて、超硬合金製部材とダイヤモンド製部材との接合強度が著しく向上する。
そして、この金属層を構成する金属または合金は、延性に富んでいるので、この金属層によって超硬合金製部材とダイヤモンド製部材との接合部に加わる衝撃が吸収されることとなって接合部に疲労破壊が生じにくい。
さらに、超硬合金製部材とダイヤモンド製部材とを接合する金属層が高融点金属またはその合金によって構成されているので、この接続構造では従来よりも高い耐熱性を持たせることができる。
【００４０】
また、本発明にかかる掘削工具の切刃片によれば、切刃片を構成する切刃基体とダイヤモンド製部材との接合強度が著しく高められていて高負荷にも耐えられ、また接合部に疲労破壊が生じにくく、耐熱性も向上しているので、この切刃片を用いた掘削工具、またはこの切刃片を有する切刃部材を用いる掘削工具では、従来よりも高速で掘削を行うことが可能となる。
【００４１】
また、本発明にかかる切刃部材によれば、切刃片とポストとの接合強度が著しく高められていて高負荷にも耐えられ、また接合部に疲労破壊が生じにくく、耐熱性も向上しているので、この切刃部材を用いた掘削工具では、従来よりも高速で掘削を行うことが可能となる。
【図面の簡単な説明】
【図１】本発明の一実施の形態にかかる掘削工具の構成を概略的に示す斜視図である。
【図２】図１に示す掘削工具を構成する切刃部材の構成を概略的に示す側面図である。
【図３】図２に示す切刃片の構成を概略的に示す斜視図である。
【図４】図３に示す切刃片の構造を示す断面図である。
【図５】本発明にかかる切刃片の他の実施形態例を示す縦断面図である。
【図６】本発明にかかる切刃部材の他の実施形態例を示す側面図である。
【符号の説明】
１掘削工具２工具本体
３切刃部材６超硬ポスト（超硬合金製部材）
７切刃片１１切刃基体（超硬合金製部材）
１２ダイヤモンド製部材１３金属層（金属箔）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a joining method and a joining structure of a cemented carbide member and a diamond member, and a cutting piece, a cutting member, and a cutting tool of a drilling tool used for excavating a well.
[0002]
[Prior art]
As a drilling tool used for drilling oil wells and other wells, a plurality of tungsten carbide-based cemented carbide posts (hereinafter referred to as cemented carbide posts) are brazed in a predetermined arrangement on the tip surface of an alloy steel tool body. The cemented carbide posts are fixed by means such as shrink fitting, and the cutting edges made entirely of ultra-high pressure sintered diamond (hereinafter referred to as sintered diamond) are directly brazed to each of the front side surfaces of the cemented carbide posts. Drilling tools are known.
In this excavation tool, the tool body is attached to the tip of the pipe, and the tool body is rotated while applying a load in the excavation direction to the tool body via the pipe, so that the excavation is performed by the cutting blade piece provided in the tool body. Is what you do.
[0003]
Here, diamond has poor wettability and is difficult to braze with a normal brazing material. Therefore, in this drilling tool, for example, Cu (copper): 20 to 40% by mass, Ti (titanium): 0.5 to 10 The cutting edge piece is brazed to the carbide post by using an Au alloy brazing material (melting point: 940 ° C.) having a composition containing Au (gold) and unavoidable impurities, the balance being Au (gold). See, for example, Patent Document 1.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-000686
[Problems to be solved by the invention]
By the way, in recent years, there is a strong demand for labor saving and energy saving of excavation work and further cost reduction. For example, in the excavation work for mining oil, etc., the daily operation cost is extremely high at 5 to 20 million yen. Therefore, in order to reduce the cost, the excavation speed is increased and the excavation work is performed in a short period of time. It is required to be terminated.
To increase the excavation speed, it is necessary to increase the load applied to the tool body or increase the rotation speed of the tool body.In recent years, however, in order to reduce pipe replacement work and refilling work, a longer and thinner pipe than before has been used. Since the load applied to the tool body via the pipe cannot be increased so much, high-speed excavation is performed by increasing the rotation speed of the tool body. For example, in the case of oil drilling, the rotation speed of the tool body has conventionally been 70 to 150 rotations / minute, whereas in recent years, the drilling has been performed at an order of magnitude higher, which is 500 to 1000 rotations / minute. .
[0006]
However, when the rotation speed of the tool body is increased in this way, the frequency of impact on the cutting edge during excavation work increases. In a drilling tool, a cemented carbide post and a cutting piece made of sintered diamond are joined by brazing as described above, and the joining strength is not so high. Is repeatedly applied to the joints, fatigue fracture may occur in these joints in a relatively short time, and the cutting piece may be peeled off from the cemented carbide post. Also, if the excavation speed is too high, the excavation heat will also increase, so that the brazing material brazing the cutting piece may melt and the cutting piece may be peeled off from the carbide post.
For this reason, the excavation speed could not be increased so far conventionally.
[0007]
The present invention has been made in view of such circumstances, and has a higher joining strength, and a method of joining a cemented carbide member and a diamond member that does not easily cause fatigue fracture, a joining structure, and a drilling tool. It is an object to provide a cutting piece, a cutting member, and a drilling tool.
[0008]
[Means for Solving the Problems]
The method for joining a cemented carbide member and a diamond member according to the present invention is a method for joining V (vanadium), Nb (niobium) and Ta (tantalum) between the cemented carbide member and the diamond member. Metal foil composed of any one of metal and unavoidable impurities, or a metal foil composed of an alloy of two or more of these metals and unavoidable impurities, sandwiches the cemented carbide member and the diamond member. And diffusion bonding with the metal foil.
[0009]
The diffusion bonding between the cemented carbide member and the diamond member and the metal foil is performed under the condition that the metal foil is sandwiched between the cemented carbide member and the diamond member under an ultra-high pressure of, for example, 5 to 6 GPa. It is performed by performing an ultra-high temperature heat treatment of １５1550 ° C.
Here, V, Nb, and Ta constituting the metal foil are not catalyst metals used for sintering diamond, so that even if the above heat treatment is performed, only a part of the metal foil is made of a cemented carbide member and The metal foil is diffused into the diamond member, and most of the metal foil remains as it is between the cemented carbide member and the diamond member to form a metal layer therebetween. In addition, since the metal or alloy constituting the metal foil is not a catalytic metal as described above, the metal or alloy diffuses only in the vicinity of the joint with the metal foil in the diamond member, and does not adversely affect the physical properties of the diamond member. .
[0010]
By performing diffusion bonding in this manner, a diffusion layer in which the components of the metal foil are diffused is formed in the vicinity of the bonding portion between the diamond member and the metal foil, and the diamond member and the metal foil are firmly connected. Joined.
Also, in the cemented carbide member, a diffusion layer in which the components of the metal foil are diffused is formed near the joint with the metal foil, so that the cemented carbide member and the metal foil are firmly joined. You.
Since the metal or alloy composing the metal foil is highly ductile, the metal foil absorbs the impact applied to the joint between the cemented carbide member and the diamond member, and the metal foil or alloy forms a metal joint. Fatigue failure hardly occurs.
Furthermore, since the metal or alloy constituting the metal foil has a higher melting point than conventionally used brazing materials, the joining structure obtained by this joining method has higher heat resistance than the joining structure by conventional brazing. have.
[0011]
Here, the heat-shrinkage rate differs between the cemented carbide member and the diamond member, but a metal layer is formed between them, and this metal layer acts as a stress buffer, so that after the above-mentioned heat treatment, it is at room temperature. When returning to normal pressure, the stress stored in the cemented carbide member and the diamond member will be absorbed by the metal layer, and it will be difficult for the stress to concentrate on the diamond member, and cracks and the like will occur in the diamond member. It hardly occurs, and the hard metal alloy member and the diamond member hardly peel off.
[0012]
The joining structure between the cemented carbide member and the diamond member according to the present invention is such that, between the cemented carbide member and the diamond member, any one metal of V, Nb, and Ta and inevitable impurities A metal layer composed of an alloy of two or more of these metals and inevitable impurities is provided, and the cemented carbide member and the diamond member are respectively diffusion bonded to the metal layer. It is characterized by having.
In the joining structure between the cemented carbide member and the diamond member, the joining strength is high, and the metal layer is made of a highly ductile metal or its alloy, and the metal layer absorbs the shock applied to the joint. Therefore, compared with the conventional joining structure by brazing, fatigue fracture is less likely to occur at the joining portion.
Further, in this joining structure, the metal layer joining the cemented carbide member and the diamond member is made of a metal or an alloy thereof having a melting point higher than that of a conventionally used brazing material. It has higher heat resistance than the structure.
[0013]
The cutting piece of the excavating tool according to the present invention is a cutting piece attached to a post provided on the tip end surface of the tool body of the excavating tool to constitute a cutting edge of the excavating tool, and It has a cemented carbide cutting blade base constituting a joining portion, and a diamond member supported by the cutting blade base, and V, Nb, and V between the cutting blade base and the diamond member. A metal layer composed of any one of Ta and an unavoidable impurity, or a metal layer composed of an alloy of two or more of these metals and an unavoidable impurity; Each member is diffusion-bonded to the metal layer.
[0014]
In the cutting blade piece of the drilling tool thus configured, a metal layer is provided between the cutting blade base and the diamond member, and the cutting base and the diamond member are diffusion-bonded to the metal layer. Therefore, the bonding strength of the diamond member to the cutting blade base is extremely high.
Furthermore, since the metal or its alloy constituting the metal layer is a metal having high ductility, the metal layer absorbs the impact applied to the joint between the cemented carbide member and the diamond member. Therefore, fatigue fracture hardly occurs at the joint.
Further, since the metal layer is made of a high melting point metal or an alloy of a high melting point metal, the joint structure has high heat resistance.
[0015]
In the cutting piece of this excavation tool, the diamond member may be made of a high heat resistant sintered diamond using magnesium carbonate (hereinafter, referred to as MgCO ₃ ) as a binder.
Here, the high heat resistant sintered diamond is obtained by sintering a diamond powder under an ultrahigh pressure of 7 to 8 GPa using, for example, MgCO ₃ as a binder at an ultrahigh temperature of 1800 to 2400 ° C. Things.
In this case, since the diamond member is made of high heat-resistant diamond having more excellent heat resistance, excavation under higher load conditions can be performed.
[0016]
A cutting blade member according to the present invention is a cutting blade member provided on a tip end surface of a tool main body of an excavating tool, and a cemented carbide post mounted on the tool main body, and mounted on the post. A diamond cutting edge piece constituting a cutting edge in the excavating tool, and between the post and the cutting edge piece, any one of V, Nb, and Ta, a metal and inevitable impurities; A metal layer made of an alloy of two or more of these metals and unavoidable impurities is provided, and the post and the cutting edge piece are each diffusion bonded to the metal layer. Features.
In the cutting blade member of the drilling tool thus configured, the joining strength between the cemented carbide post and the diamond cutting blade piece is remarkably high, and the joint does not easily cause fatigue fracture, and the joint structure has a high heat resistance. The nature is also high.
[0017]
A cutting blade member according to the present invention is a cutting blade member provided on a tip end surface of a tool body of an excavating tool, and includes a post mounted on the tool main body, and a cutting device mounted on the post and cutting on the excavating tool. And a cutting edge piece constituting a blade, wherein the cutting edge piece is the cutting edge piece according to claim 3 or 4.
In the cutting blade member of the drilling tool configured as described above, the joining strength of the diamond member to the cemented carbide cutting blade base is remarkably high, fatigue fracture is hardly generated at the joint, and the heat resistance of the joint structure is also low. Tall cutting pieces are used as cutting edges.
[0018]
The excavating tool according to the present invention is an excavating tool in which a cutting blade member having a cutting blade piece mounted on a post is mounted on a tip end surface of a tool body, and the cutting blade piece is according to claim 3 or 4. Or a cutting blade member according to claim 5 or 6 is used as the cutting blade member.
In the drilling tool configured as described above, the joining strength of the diamond member to the cemented carbide cutting edge base is remarkably high, fatigue fracture is less likely to occur in the joint, and the cutting edge piece has high heat resistance of the joint structure. Excavation is performed using a cutting edge member that has extremely high joining strength between a cemented carbide post and a diamond cutting blade piece, hardly causes fatigue fracture at the joint, and has high heat resistance of the joining structure. .
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the joining method and joining structure between a cemented carbide member and a diamond member according to the present invention are applied to a cutting blade of a drilling tool.
Here, FIG. 1 is a perspective view schematically showing a configuration of the excavating tool according to the present embodiment, and FIG. 2 is a schematic diagram showing a configuration of a cutting blade member constituting the excavating tool according to the present embodiment. FIG. 3 is a perspective view schematically showing the configuration of the cutting blade according to the present embodiment, and FIG. 4 is a cross-sectional view showing the structure of the cutting blade according to the present embodiment.
[0020]
The excavating tool 1 according to the present embodiment includes a substantially disk-shaped tool body 2 made of alloy steel or the like specified in JIS SCH415, and a plurality of cutting blade members 3 provided in a predetermined arrangement on the tip end surface of the tool body 2. have. The cutting blade member 3 is attached to the tool body 2 by means such as brazing or shrink fitting.
The cutting blade member 3 includes a cemented carbide post 6 having a columnar shape and made of cemented carbide, and a cutting blade piece 7 attached to a side of the cemented carbide post 6 facing the excavation direction by brazing or the like. In the present embodiment, cemented carbide post 6 is made of a general tungsten carbide-based cemented carbide.
[0021]
The cutting blade piece 7 has a cutting blade base 11 made of a cemented carbide which forms a joint portion with the carbide post 6, and a diamond member 12 supported by the cutting blade base 11. A metal layer 13 is provided between the substrate 11 and the diamond member 12, and the cutting blade substrate 11 and the diamond member 12 are respectively diffusion bonded to the metal layer 13.
[0022]
The cutting blade base 11 is formed in a substantially disk shape, one surface of which is a brazing surface to be brazed to the carbide post 6, and the other surface facing the one surface (that is, the surface facing the excavation direction). A cutout-shaped concave portion is formed on the (side) side, and this concave portion serves as a mounting seat 11 a for mounting the diamond member 12. The mounting seat 11a has the same shape as the outer shape of the diamond member 12, and is provided in a region of the cutting blade piece 7 where wear is likely to occur during excavation work. In the present embodiment, the mounting seat 11a has a fan shape in plan view.
The cutting blade base 11 is made of a tungsten carbide-based cemented carbide using Co (cobalt) as a binder, that is, a common cemented carbide. In the present embodiment, the cutting edge substrate 11 is made of a cemented carbide containing 10% by mass of Co as a binder and the remainder being WC (tungsten carbide) and unavoidable impurities. Since the cemented carbide has high strength and high toughness, the cutting blade base 11 made of the ultra-high alloy acts as a shock absorber for absorbing the thermal and mechanical shock applied during the excavation work at the cutting blade piece 7. .
[0023]
The diamond member 12 is provided in an area of the cutting blade piece 7 where wear is likely to occur during excavation work. In the present embodiment, the ratio of the diamond member 12 to the front surface of the cutting blade 7 is set to 25 to 60 area%.
Here, the diamond member 12 is composed of a normal sintered diamond alone or a single highly heat-resistant sintered diamond having more excellent heat resistance. Or a composite of In the present embodiment, the diamond member 12 is composed of a single piece of heat-resistant sintered diamond alone.
[0024]
The metal layer 13 provided between the cutting blade base 11 and the diamond member 12 is made of any one of V, Nb, and Ta and an unavoidable impurity, or an alloy of two or more of these metals. It consists of unavoidable impurities. In the present embodiment, the metal layer 13 is made of a foil made of Ta, and has a thickness D of 0.02 to 0.1 mm.
Here, V, Nb, and Ta are all high melting point metals (the melting point of V is 1700 ° C., the melting point of Nb is 2467 ° C., the melting point of Ta is 2850 ° C.), and the melting points of these alloys are also the same. high. Further, V, Nb, and Ta are all highly ductile metals among the high melting point metals, and their alloys are also similarly highly ductile.
[0025]
The cutting blade piece 7 configured as described above is created as follows.
First, the cutting blade base 11 and the diamond member 12 are manufactured in desired shapes.
The cutting blade base 11 is manufactured in the same manner as a normal cemented carbide product. For example, by forming and sintering a raw material powder of a cemented carbide to form a disc-shaped cemented carbide chip, and performing cutting or the like on one surface side of the cemented carbide chip to form the mounting seat 11a, It is obtained by molding and sintering a raw material powder of a cemented carbide into a disk shape having a mounting seat 11a.
[0026]
The diamond member 12 is produced using, as raw material powders, diamond powder having an average particle diameter of 10 μm and a purity of 99.9% or more, and MgCO ₃ powder having an average particle diameter of 10 μm and a purity of 95% or more.
First, MgCO ₃ powder is press-molded at a pressure of 100 MPa to obtain a green compact having a desired shape. Subsequently, the green compact is charged into a Ta (tantalum) capsule, and then the diamond powder is filled on the green compact in the capsule.
In this state, by performing an ultra high pressure sintering was charged in a (carbide sintering device used in the conventional sintered diamond fabrication) capsule belt type super high pressure sintering apparatus, 4.0 wt% of MgCO ₃ To obtain a block of sintered diamond.
In the present embodiment, the ultra-high pressure sintering is performed by heating to 2250 ° C. and maintaining the pressure for 30 minutes while applying a pressure of 7.7 Gpa.
Then, the block of the sintered diamond is polished with a diamond grindstone to be roughly shaped, and then a diamond piece having a desired shape is further cut out by laser processing to obtain the diamond member 12.
[0027]
Subsequently, a metal foil made of any one of V, Nb, and Ta and an unavoidable impurity, or a metal foil between them, between the cutting blade base 11 and the diamond member 12 obtained as described above. With a metal foil (having a thickness of 0.02 to 0.1 mm) made of an alloy of two or more metals and unavoidable impurities, the diamond member 12 is fitted to the mounting seat 11a of the cutting blade base 11. Put in.
Further, the cutting blade base body 11, the metal foil, and the diamond member 12 temporarily assembled as described above are loaded into a belt-type ultra-high pressure sintering apparatus, subjected to an ultra-high temperature and high pressure heat treatment, and these members are joined. The cutting blade piece 7 according to the present invention is obtained by being integrated. In the present embodiment, the heat treatment at the ultra-high temperature and high pressure is performed by heating to 1500 ° C. under a pressure of 5.5 GPa and holding for 30 minutes.
[0028]
By this heat treatment, the components of the metal foil diffuse into the cutting blade base 11 and the diamond member 12, respectively, and the components constituting the metal foil diffuse near the interface with the metal foil in the cutting blade base 11 and the diamond member 12. Thus, the super-high-pressure heat melting diffusion layers S1 and S2 are formed.
Here, V, Nb, and Ta constituting the metal foil are not all catalytic metals used for sintering diamond, so that even if the above heat treatment is performed, only a part of the metal foil forms the cutting edge substrate 11 and the diamond. Most of the metal foil remains as it is between the cutting edge substrate 11 and the diamond member 12 to form the metal layer 13 therebetween. In addition, since the metal or its alloy that constitutes the metal foil is not a catalytic metal as described above, it diffuses only in the vicinity of the joint with the metal foil in the diamond member 12 and adversely affects the physical properties of the diamond member 12. Do not give.
[0029]
Among the ultrahigh-pressure heat-fusion diffusion layers S1 and S2, the ultrahigh-pressure heat-fusion diffusion layer S1 formed on the cutting edge base 11 extends from the joint surface with the metal layer 13 to a depth of 0.1 to 0.5 mm. The ultra-high pressure heat melting diffusion layer S2 formed on the diamond member 12 is formed over a depth of 0.01 to 0.1 mm from a bonding surface with the metal layer 13.
Due to the presence of the ultrahigh-pressure heat-melting diffusion layer, the cutting edge substrate 11 and the diamond member 12 are respectively strongly bonded to the metal layer 13.
The state of the ultrahigh-pressure heat-melting diffusion layers S1 and S2 and the formation range thereof can be examined by observing the structure using a metallographic microscope.
[0030]
Here, the cutting blade base 11 and the diamond member 12 have different heat shrinkage rates, but a metal layer 13 is formed between them, and since the metal layer 13 acts as a stress buffer, When returning to normal temperature and normal pressure later, the stress stored in the cutting blade base 11 and the diamond member 12 is absorbed by the metal layer 13, so that stress is less likely to concentrate on the diamond member 12 and the diamond member Cracks and the like are not easily generated in the cutting blade base 12 and the diamond member 12 is hardly separated from the cutting blade base 11.
[0031]
The cutting blade piece 7 thus obtained is brazed to the carbide post 6 to form the cutting blade member 3. The cutting tool 3 is mounted on the tool body 2 to obtain the excavating tool 1.
[0032]
The excavating tool 1 thus configured is used for excavating work in the same manner as a conventional excavating tool.
In this excavating tool 1, the cutting blade base 11 and the diamond member 12 are firmly joined at the cutting blade piece 7. Further, since the metal or its alloy constituting the metal layer 13 provided between the cutting blade base 11 and the diamond member 12 is highly ductile, the metal layer 13 allows the cutting blade base 11 and the diamond member 12 to be formed. Thus, the impact applied to the joint is absorbed and the joint is less likely to undergo fatigue fracture.
For this reason, the excavation tool 1 can perform excavation under high-load conditions such as high-speed excavation.
The melting point of the metal or alloy constituting the metal layer 13 is sufficiently higher than the melting point of the conventional brazing material, and the heat resistance of the joint structure between the cutting edge substrate 11 and the diamond member 12 is improved as compared with the conventional case. Therefore, excavation can be performed at a high speed, which was impossible with a conventional excavation tool due to the problem of the heat resistance of the brazing material.
[0033]
Here, when high-speed excavation is performed, an extremely high thermal mechanical impact is applied to the cutting blade piece 7. The diamond member 12 itself used as the cutting blade piece 7 is extremely hard, but on the other hand, is brittle, so that a minute chip is likely to be generated when it receives a strong impact. In the diamond member 12, the progress of abrasion is remarkably promoted due to the generation of a minute chip, and as a result, the service life is reached in a relatively short time.
[0034]
According to the study of the present inventors, in the cutting tool 7, the wear caused by excavation progresses over the entire front surface of the cutting tool from the relation of the mounting position of the cutting tool 3 in the cutting tool 1. Instead, certain areas of the front face of the cutting edge are worn locally, and the remaining wear is only a small amount that follows this localized wear and the area where this localized wear occurs. Was found to be 25% by area or less of the front surface of the cutting blade piece.
Therefore, in the present embodiment, the diamond member 12 having excellent wear resistance is provided in a region where local wear occurs in the cutting blade piece 7, and the other portion is made of an ultra-high alloy having shock absorbing performance. It is constituted by a cutting blade base 11 made of. Thereby, while making it difficult for local wear of the cutting blade 7 to occur, the thermal mechanical shock applied to the cutting blade 7 at the time of excavation is absorbed by the cutting blade base 11, and the minute chipping of the diamond member 12 due to the shock is prevented. As a result, the life of the cutting blade piece 7 was improved.
[0035]
Here, when the ratio of the diamond member 12 to the front surface of the cutting edge piece is less than 25% by area, the cutting edge substrate 11 made of cemented carbide directly participates in excavation, and wear of the cutting edge substrate 11 progresses. Resulting in. On the other hand, when the ratio exceeds 60 area%, the ratio occupied by the cutting blade base 11 acting as the shock absorbing portion becomes relatively small, and the extremely high thermal mechanical shock generated in the high-speed rotation operation is sufficiently reduced. It cannot be absorbed, and as a result, the occurrence of minute cracks particularly in the diamond member 12 rapidly increases. For this reason, the ratio of the diamond member 12 occupying the front surface of the cutting piece 7 is preferably 25 to 60 area%, and more preferably 30 to 45 area%.
[0036]
In the above-described embodiment, the cutting blade piece 7 includes the cutting blade base 11 having the fan-shaped mounting seat 11a and the fan-shaped diamond member 12 made of heat-resistant sintered diamond. Without being limited, the member constituting the cutting blade piece 7 can have another arbitrary shape.
For example, as shown in FIG. 5A, the cutting blade piece 7 may have a configuration in which a plate-shaped cutting blade base 11 and a plate-shaped diamond member 12 are simply joined via a metal layer 13. Further, as shown in FIG. 5 (b), a part of the diamond member 12 is a high heat resistant diamond part 12a made of high heat resistant sintered diamond, and the remaining part is a sintered diamond made of normal sintered diamond. The structure may be a part 12b, or a structure in which a high heat resistant diamond part 12a is embedded in a sintered diamond part 12b as shown in FIG.
[0037]
Further, in the above-described embodiment, an example in which the joining method and the joining structure of the cemented carbide member and the diamond member according to the present invention are applied to the cutting blade piece 7 of the excavating tool 1 has been described. For example, as shown in FIG. 6, when the cutting piece 7a entirely made of normal sintered diamond or high heat-resistant diamond is used as the cutting piece as shown in FIG. May be applied to the joining between the cemented carbide post 6 and the cutting blade piece 7a.
[0038]
Further, the joining method and the joining structure of the cemented carbide member and the diamond member according to the present invention are not limited only to the above examples, and the cemented carbide member and the diamond member are not limited to the above examples. Any object can be applied as long as it can be joined.
[0039]
【The invention's effect】
According to the method and structure for joining a cemented carbide member and a diamond member according to the present invention, the cemented carbide member and the diamond member diffuse into the metal layer of the composition provided therebetween. Since the members are joined, the joining strength between the cemented carbide member and the diamond member is remarkably improved as compared with the conventional joining structure by brazing.
Since the metal or alloy composing the metal layer is rich in ductility, the metal layer absorbs the impact applied to the joint between the cemented carbide member and the diamond member, and Hardly cause fatigue fracture.
Furthermore, since the metal layer for joining the cemented carbide member and the diamond member is made of a high melting point metal or an alloy thereof, this connection structure can have higher heat resistance than before.
[0040]
Further, according to the cutting blade piece of the excavating tool according to the present invention, the joining strength between the cutting base and the diamond member constituting the cutting piece is remarkably increased, so that it can withstand a high load, and Since the fatigue fracture hardly occurs and the heat resistance is also improved, the excavation tool using the cutting edge piece, or the excavation tool using the cutting edge member having the cutting edge piece, should excavate at a higher speed than before. Becomes possible.
[0041]
Further, according to the cutting blade member of the present invention, the joining strength between the cutting blade piece and the post is remarkably increased, which can withstand a high load, and the joint does not easily undergo fatigue fracture, and the heat resistance is also improved. Therefore, the excavation tool using the cutting blade member can excavate at a higher speed than before.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a configuration of a drilling tool according to an embodiment of the present invention.
FIG. 2 is a side view schematically showing a configuration of a cutting blade member constituting the excavating tool shown in FIG.
FIG. 3 is a perspective view schematically showing a configuration of a cutting blade piece shown in FIG. 2;
FIG. 4 is a sectional view showing a structure of a cutting blade piece shown in FIG. 3;
FIG. 5 is a longitudinal sectional view showing another embodiment of the cutting blade piece according to the present invention.
FIG. 6 is a side view showing another embodiment of the cutting blade member according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drilling tool 2 Tool main body 3 Cutting blade member 6 Carbide post (member made of cemented carbide)
7 Cutting edge piece 11 Cutting edge base (Carbide alloy member)
12 Diamond member 13 Metal layer (metal foil)

Claims

A metal foil made of any one of V, Nb, and Ta and an unavoidable impurity, or an alloy of two or more of these metals is inevitable between a cemented carbide member and a diamond member. Sandwich metal foil made of impurities,
A method for joining a cemented carbide member and a diamond member, wherein the cemented carbide member and the diamond member are each diffusion bonded to the metal foil.

A metal layer made of any one of V, Nb, and Ta and an unavoidable impurity, or an alloy of an alloy of two or more of these metals, between a cemented carbide member and a diamond member A metal layer made of impurities is provided,
A joining structure between a cemented carbide member and a diamond member, wherein the cemented carbide member and the diamond member are each diffusion bonded to the metal layer.

A cutting blade piece that is mounted on a post provided on a tip end surface of a tool body of the drilling tool and constitutes a cutting blade in the drilling tool,
A cemented carbide cutting blade base constituting a joint with the post,
Having a diamond member supported by the cutting blade substrate,
Between the cutting blade base and the diamond member, a metal layer composed of any one of V, Nb and Ta and an unavoidable impurity, or an alloy of two or more of these metals A metal layer made of unavoidable impurities is provided,
The cutting blade piece of a drilling tool, wherein the cutting blade base and the diamond member are each diffusion bonded to the metal layer.

The cutting edge piece of a drilling tool according to claim 3, wherein the diamond member is made of a high heat resistant sintered diamond using magnesium carbonate as a binder.

A cutting blade member provided on a tip surface of a tool body of the excavating tool,
A cemented carbide post mounted on the tool body,
Having a diamond cutting blade piece mounted on the post and constituting a cutting blade in the excavating tool,
A metal layer composed of any one of V, Nb, and Ta and an unavoidable impurity, or an alloy of two or more of these metals and an unavoidable impurity is provided between the post and the cutting blade piece. A metal layer consisting of
The cutting member of a drilling tool, wherein the post and the cutting piece are respectively diffusion bonded to the metal layer.

A cutting blade member provided on a tip surface of a tool body of the excavating tool,
A post attached to the tool body,
A cutting edge piece that is attached to the post and constitutes a cutting edge of the excavating tool,
A cutting blade member for an excavating tool, wherein the cutting blade piece is the cutting blade piece according to claim 3.

An excavation tool to which a cutting blade member formed by mounting a cutting blade piece to a post is mounted on a tip surface of a tool body,
An excavating tool, wherein the cutting edge piece according to claim 3 or 4 is used as the cutting edge piece, or the cutting edge member according to claim 5 or 6 is used as the cutting edge member.