JP4088831B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance under high-speed heavy cutting conditions. - Google Patents

Description

【００１８】
【表２】

【００１９】
【表３】

【００２０】
（実施例２）
原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒＣ粉末、同２．３μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ（質量比で、ＴｉＣ／ＷＣ＝５０／５０）粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表４に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体を形成し、さらに前記の３種の丸棒焼結体から、研削加工にて、表４に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法、並びにいずれもねじれ角３０度の４枚刃スクエアの形状をもった超硬基体（エンドミル）Ｂ−１〜Ｂ−８をそれぞれ製造した。
【００２１】
ついで、これらの超硬基体（エンドミル）Ｂ−１〜Ｂ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される蒸着装置、すなわち装置内中央部に超硬基体装着用テーブルを設け、前記テーブルの外周に沿って、いずれも純度：９９．９８質量％の高純度炭素粉末の成形体からなる４枚のターゲットを、それぞれカソード電極（蒸発源）として配置した蒸着装置を用い、この装置の前記テーブル上に、これの中心軸から半径方向に所定距離離れた位置に複数の上記超硬基体をそれぞれ前記ターゲットに対面して自転可能に装着し、まず、装置内を真空排気して０．５Ｐａの真空に保持しながら、ヒーターで装置内を２００℃に加熱した後、Ａｒガスを装置内に導入して３０Ｐａの圧力のＡｒ雰囲気とし、この状態で前記テーブル上で自転する前記超硬基体に−８００Ｖのバイアス電圧を印加して前記超硬基体表面を２０分間Ａｒガスボンバード洗浄し、ついで前記超硬基体に印加するバイアス電圧を−５０Ｖ、前記ターゲット（カソード電極）のそれぞれに８０Ａのアーク電流を付加して、アーク放電を発生させ、このアーク放電によって前記カソード電極（蒸発源）から炭素を蒸発させると共に、装置内にＡｒと水素の混合ガスを、装置内雰囲気の圧力を常に３Ｐａに保持した状態で、かつ前記Ａｒと水素の混合割合を周期的に変化させながら導入し、もって前記テーブル上で自転する超硬基体の表面に、水素含有の非晶質炭素系硬質被覆層からなり、かつ層厚方向に沿って表５に示される目標水素含有量の水素最高含有点と水素最低含有点とが交互に同じく表５に示される目標間隔で繰り返し存在し、かつ前記水素最高含有点から前記水素最低含有点、前記水素最低含有点から前記水素最高含有点へ、水素含有量が連続的に変化する濃度分布構造を有し、かつ同じく表５に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２２】
また、比較の目的で、上記の蒸着装置に導入されるＡｒと水素の混合ガスにおけるＡｒと水素の混合割合を硬質被覆層形成開始から終了まで一定にする以外は同一の条件で、上記の超硬基体（エンドミル）Ｂ−１〜Ｂ−８のそれぞれの表面に、表６に示される目標水素含有量および目標層厚を有し、かつ水素含有の非晶質炭素系硬質被覆層からなるが、層厚方向に沿って実質的に水素含有量に変化のない硬質被覆層を蒸着することにより、従来被覆超硬工具に相当する比較表面被覆超硬合金製エンドミル（以下、比較被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２３】
つぎに、上記本発明被覆超硬エンドミル１〜８および比較被覆超硬エンドミル１〜８のうち、本発明被覆超硬エンドミル１〜３および比較被覆超硬エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ａ２０２４（Ｃｕ：４％、Ｍｎ：０．６％、Ｍｇ：１．５％、残：Ａｌ）の板材、
切削速度：３００ｍ／ｍｉｎ．、
溝深さ（切り込み）：１２ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件（以下、切削条件１という。ただし、通常条件での切削速度および切り込みは１５０ｍ／ｍｉｎ．および６ｍｍ）でのＡｌ合金の乾式高速高切り込み溝切削加工試験、本発明被覆超硬エンドミル４〜６および従来被覆超硬エンドミル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＡＣ４Ｂ（Ｃｕ：３％、Ｓｉ：８．５％、残：Ａｌ）の板材、
切削速度：３００ｍ／ｍｉｎ．、
溝深さ（切り込み）：１０ｍｍ、
テーブル送り：２０００ｍｍ／分、
の条件（以下、切削条件２という。ただし、通常の条件での切削速度およびテーブル送りは１５０ｍ／ｍｉｎ．および１０００ｍｍ／分）でのＡｌ合金の乾式高速高送り溝切削加工試験、本発明被覆超硬エンドミル７，８および比較被覆超硬エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｃ１０２０（純度：９９．９８％の純銅）の板材、
切削速度：１６０ｍ／ｍｉｎ．、
溝深さ（切り込み）：３０ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件（以下、切削条件３という。ただし、通常の条件での切削速度は８０ｍ／ｍｉｎ．、同溝深さは１５ｍｍ、同テーブル送りは５００ｍｍ／分）での純銅の乾式高速高切り込みおよび高送り溝切削加工試験をそれぞれ行い、使用寿命に至るまでの切削溝長を測定した。なお、上記の溝切削加工試験おける使用寿命は、切刃部の外周刃の逃げ面摩耗幅で評価し、それぞれ前記逃げ面摩耗幅が上記の切削条件１では０．１ｍｍ、同切削条件２では０．２ｍｍ、および同切削条件３では０．１ｍｍに至った時点をもって使用寿命とした。この測定結果を表５，６にそれぞれ示した。
【００２４】
【表４】

【００２５】
【表５】

【００２６】
【表６】

【００２７】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｂ−１〜Ｂ−３形成用）、１３ｍｍ（超硬基体Ｂ−４〜Ｂ−６形成用）、および２６ｍｍ（超硬基体Ｂ−７、Ｂ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｃ−１〜Ｃ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｃ−４〜Ｃ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｃ−７、Ｃ−８）の寸法、並びにいずれもねじれ角３０度の２枚刃形状をもった超硬基体（ドリル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２８】
ついで、これらの超硬基体（ドリル）Ｃ−１〜Ｃ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される蒸着装置に装入し、上記実施例２と同一の条件で、層厚方向に沿って表７に示される目標水素含有量の水素最高含有点と水素最低含有点とが交互に同じく表７に示される目標間隔で繰り返し存在し、かつ前記水素最高含有点から前記水素最低含有点、前記水素最低含有点から前記水素最低含有点へ、水素含有量が連続的に変化する濃度分布構造を有し、かつ同じく表７に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル（以下、本発明被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００２９】
また、比較の目的で、上記の超硬基体（ドリル）Ｃ−１〜Ｃ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される蒸着装置に装入し、上記実施例２と同一の条件で、表８に示される目標水素含有量および目標層厚を有し、かつ層厚方向に沿って実質的に水素含有量に変化のない硬質被覆層を蒸着することにより、従来被覆超硬工具に相当する比較表面被覆超硬合金製ドリル（以下、比較被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３０】
つぎに、上記本発明被覆超硬ドリル１〜８および比較被覆超硬ドリル１〜８のうち、本発明被覆超硬ドリル１〜３および比較被覆超硬ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＡＣ４Ｂ（Ｃｕ：３％、Ｓｉ：８．５％、残：Ａｌ）の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．６ｍｍ／ｒｅｖ、
穴深さ：１０ｍｍ、
の条件（以下、切削条件１という。ただし、通常の条件での切削速度および送りは８０ｍ／ｍｉｎ．および０．２ｍｍ／ｒｅｖ．）でのＡｌ合金の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル４〜６および比較被覆超硬ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｃ２１００（Ｚｎ：５％、残：Ｃｕ）の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．６ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件（以下、切削条件２という。ただし、通常の条件での切削速度および送りは９０ｍ／ｍｉｎ．および０．３ｍｍ／ｒｅｖ．）での銅合金の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル７，８および比較被覆超硬ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ａ４０３２（Ｓｉ：１２％，Ｃｕ：１％、Ｍｇ：１％、Ｎｉ：０．８％、残：Ａｌ）の板材、
切削速度：２５０ｍ／ｍｉｎ．、
送り：０．７ｍｍ／ｒｅｖ、
穴深さ：４０ｍｍ、
の条件（以下、切削条件３という。ただし、通常の条件での切削速度および送りは１１０ｍ／ｍｉｎ．および０．３ｍｍ／ｒｅｖ．）でのＡｌ合金の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式穴あけ切削加工試験（水溶性切削油使用）でも使用寿命に至るまでの穴あけ加工数を測定した。なお、上記の湿式穴あけ切削加工試験おける使用寿命は、先端切刃面の逃げ面摩耗幅で評価し、それぞれ前記逃げ面摩耗幅が上記の切削条件１では０．３ｍｍ、同切削条件２では０．２ｍｍ、および同切削条件３では０．２ｍｍに至った時点をもって使用寿命とした。この測定結果を表７、８にそれぞれ示した。
【００３１】
【表７】

【００３２】
【表８】

【００３３】
この結果得られた本発明被覆超硬工具としての本発明被覆超硬チップ１〜１０、本発明被覆超硬エンドミル１〜８、および本発明被覆超硬ドリル１〜８、並びに従来被覆超硬工具に相当する比較被覆超硬チップ１〜１０、比較被覆超硬エンドミル１〜８、および比較被覆超硬ドリル１〜８を構成する硬質被覆層について、厚さ方向に沿って水素含有量を高周波グロー放電分光分析装置を用いて測定したところ、前記本発明被覆超硬工具の硬質被覆層では、水素最高含有点と水素最低含有点とがそれぞれ目標値と実質的に同じ水素含有量および間隔で交互に繰り返し存在し、かつ前記水素最高含有点から前記水素最低含有点、前記水素最低含有点から前記水素最高含有点へ、水素含有量が連続的に変化する濃度分布構造を有することが確認され、さらに硬質被覆層の平均層厚も目標全体層厚と実質的に同じ値を示した。一方、前記従来被覆超硬工具の硬質被覆層では、目標水素含有量と実質的に同じ水素含有量および目標全体層厚と実質的に同じ全体平均層厚を示すものの、厚さ方向に沿った水素含有量に変化は見られず、層全体に亘って均質な水素含有量を示すものであった。
【００３４】
【発明の効果】
表２〜８に示される結果から、硬質被覆層が層厚方向に、すぐれた強度を有する水素最高含有点と、高硬度を有する水素最低含有点とが交互に所定間隔をおいて繰り返し存在し、かつ前記水素最高含有点から前記水素最低含有点、前記水素最低含有点から前記水素最高含有点へ、水素含有量が連続的に変化する濃度分布構造を有する本発明被覆超硬工具は、いずれも各種の被削材、特にＡｌ合金やＣｕ合金の切削加工を、高速重条件で行なった場合にも、硬質被覆層が前記水素最高含有点によってすぐれた強度を発揮し、前記硬質被覆層にチッピングが発生するのを抑制し、さらに硬質炭素を高含有の前記水素最低含有点によって層自体が著しく高い硬さを具備することと相俟って、すぐれた耐摩耗性を発揮するのに対して、層厚方向に沿って実質的に水素含有量に変化がない硬質被覆層を蒸着してなる従来被覆超硬工具（比較被覆超硬工具）においては、高速重切削条件では、硬質被覆層の水素含有量が高くなればなるほど、前記硬質被覆層の強度は比例的に上昇するが、硬さが低下するようになることから、摩耗進行が促進され、一方硬質被覆層の水素含有量が低くなればなるほど、前記硬質被覆層の硬さは比例的に上昇するが、強度が低下するようになることから、チッピングが発生し易くなり、いずれの場合も比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、各種の被削材、特にＡｌ合金やＣｕ合金などの被削材の切削加工を、高速で、かつ大きな機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、切刃にチッピングの発生なく、硬質被覆層がすぐれた耐摩耗性を発揮するものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたスパッタリング装置を適用した蒸着装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を適用した蒸着装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。[0001]
BACKGROUND OF THE INVENTION
In the present invention, the hard coating layer has both high hardness and high strength. Therefore, various kinds of work materials, in particular, work materials such as Al alloys and Cu alloys can be cut at high speed and with high mechanical impact. A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance without causing chipping (small chipping) in the hard coating layer even under heavy cutting conditions such as cutting and high feed (hereinafter referred to as coating) This is related to carbide tools.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. Also, the throwaway tip is detachably attached and cutting is performed in the same way as the solid type end mill Throwaway end mill tools are known.
[0003]
Further, as a coated carbide tool, the ratio of hydrogen to the total amount of carbon on the surface of a substrate (hereinafter referred to as a carbide substrate) made of a tungsten carbide (hereinafter referred to as hydrogen) -based cemented carbide is 0.00. Coated carbide tools formed by vapor-depositing amorphous carbon-based hard coating layers containing 1 to 40 atomic% at an average average layer thickness of 1 to 10 μm have been proposed. It is also known to be used for continuous cutting and intermittent cutting of a work material such as Al alloy and Cu alloy (see, for example, Patent Documents 1 and 2).
[0004]
[Patent Document 1]
JP 2001-62605 A
[Patent Document 2]
Japanese Patent Laid-Open No. 3-158455
[0005]
[Problems to be solved by the invention]
In recent years, there has been a remarkable increase in performance of cutting devices. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting processing. Although there is a tendency that cutting under heavy cutting conditions such as high feed is strongly demanded, the above-mentioned conventional coated carbide tools have different characteristics depending on the hydrogen content. Although it has high hardness and excellent wear resistance at high speed cutting, it does not have sufficient strength, so chipping occurs in heavy cutting such as high cutting with high mechanical impact and high feed. It is easy to do, and this leads to a service life in a relatively short time. On the other hand, since the hydrogen content has a relatively high strength on the high content side, the above high cutting and high feed, etc. Although it shows excellent chipping resistance in heavy cutting, it has low hardness, so of course in the heavy cutting conditions, especially in high speed cutting, the progress of wear must be remarkably fast and the service life must be short. Thus, the above-mentioned conventional coated carbide tool does not exhibit satisfactory cutting performance at high speed and under heavy cutting conditions such as high cutting and high feed with a large mechanical impact, that is, high speed heavy cutting conditions. Is the current situation.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed a coated carbide tool in which the hard coating layer exhibits excellent wear resistance without occurrence of chipping, particularly in cutting under high-speed heavy cutting conditions. Therefore, as a result of conducting research, focusing on the hard coating layer that constitutes the above conventional coated carbide tool,
(A) The hard coating layer constituting the above-mentioned conventional coated carbide tool has a substantially uniform composition throughout the layer thickness, and thus has a uniform hardness and strength. For example, FIG. 1 and FIG. (A) is a schematic plan view, and (b) is a schematic front view of the vapor deposition apparatus, that is, a carbide substrate mounting table is provided at the center of the apparatus, and along the outer periphery of the table, both Using a vapor deposition apparatus in which a target made of a high purity carbon powder compact is disposed as a cathode electrode (evaporation source) of a sputtering apparatus (FIG. 1) and an arc ion plating apparatus (FIG. 2), In addition, a plurality of cemented carbide substrates are mounted so as to be able to rotate while facing each of the targets at positions spaced apart from the central axis in a radial direction, and in this state, the reaction atmosphere in the apparatus is Ar gas and hydrogen gas. The mixture ratio of Ar and hydrogen is periodically changed, that is, the ratio of hydrogen is the highest and the ratio of Ar is the lowest, preferably the ratio of hydrogen to the total amount of Ar When the hydrogen-containing gas mixture is introduced at 15 to 20% by volume, the ratio of hydrogen is the lowest, the ratio of Ar is the highest, and preferably the ratio of hydrogen to the total amount of Ar is 0.1 to Corresponding to the setting of the hydrogen low-containing mixed gas introduction point of 5% by volume, and continuously reducing the hydrogen ratio from the high hydrogen-containing mixed gas introduction point to the low hydrogen-containing mixed gas introduction point The ratio of Ar is continuously increased, while the ratio of hydrogen is continuously increased from the time when the low hydrogen-containing mixed gas is introduced to the time when the high hydrogen-containing mixed gas is introduced. The ratio of Ar continuously While the periodic ratio change to be reduced is added to the mixed gas of Ar and hydrogen introduced into the apparatus, the carbide substrate itself is rotated for the purpose of uniformizing the thickness of the hard coating layer formed by vapor deposition. When a glow discharge (sputtering apparatus) or arc discharge (arc ion plating apparatus) is generated on the electrode (evaporation source) to form a hard coating layer on the surface of the superhard substrate, the resulting hard coating layer is formed of hydrogen. Is formed of an amorphous carbon-based hard coating layer, and at the time of introduction of the high hydrogen-containing mixed gas, a hydrogen maximum content point is formed in the hard coating layer, and at the time of introduction of the low hydrogen-containing mixed gas, the hydrogen minimum content point Is formed, and the maximum hydrogen content point and the minimum hydrogen content point are arranged in the layer along the layer thickness direction by a periodic change in the mixing ratio of Ar and hydrogen of the mixed gas introduced into the apparatus. As a result, it appears repeatedly alternately and has a concentration distribution structure in which the hydrogen content continuously changes from the highest hydrogen content point to the lowest hydrogen content point and from the lowest hydrogen content point to the highest hydrogen content point. .
[0007]
(B) In the formation of the amorphous carbon-based hard coating layer having the hydrogen continuous continuous concentration distribution structure of (a) above, the mixing ratio of Ar and hydrogen in the mixed gas introduced into the apparatus, and the mixing ratio Adjust for periodic changes
The hydrogen content at the highest hydrogen content point is 30 to 40 atomic% in the ratio of the total amount with carbon,
On the other hand, the hydrogen content at the lowest hydrogen content point is 0.1 to 10 atomic% in the proportion of the total amount with carbon,
And the interval in the thickness direction of the adjacent hydrogen highest content point and hydrogen lowest content point adjacent to each other is 0.01 to 0.1 μm,
The highest hydrogen content point portion has a relatively high hydrogen content and is significantly higher than the lowest hydrogen content point portion. The hydrogen content is relatively low and the content ratio of hard carbon is extremely high. Therefore, the hardness is much higher and the distance between the highest hydrogen content point and the lowest hydrogen content point is extremely small. From the above, the coated carbide tool formed with the hard coating layer having such a structure has a variety of work materials, in particular, while maintaining high strength as a property of the entire layer. Even when cutting a work material such as an Al alloy or Cu alloy at high speed and under heavy cutting conditions such as high cutting and high feed with a large mechanical impact, chipping, etc. Raw without becoming so exhibits excellent wear resistance. The research results shown in (a) and (b) above were obtained.
[0008]
The present invention has been made based on the above research results, and is formed by vapor-depositing a hydrogen-containing amorphous carbon-based hard coating layer with a total average layer thickness of 1 to 10 μm on the surface of a cemented carbide substrate. In coated carbide tools,
In the amorphous carbon-based hard coating layer, the hydrogen maximum content point and the hydrogen minimum content point are alternately present at predetermined intervals along the layer thickness direction, and the hydrogen minimum content point is from the hydrogen maximum content point. Containing point, having a concentration distribution structure in which the hydrogen content continuously changes from the hydrogen minimum content point to the hydrogen maximum content point,
Furthermore, the hydrogen content at the hydrogen maximum content point is 30 to 40 atomic% in the proportion of the total amount with carbon,
The hydrogen content at the minimum hydrogen content point is 0.1 to 10 atomic% as a percentage of the total amount with carbon,
And the interval between the adjacent hydrogen maximum content point and the hydrogen minimum content point adjacent to each other is 0.01 to 0.1 μm.
It is characterized by a coated carbide tool that exhibits excellent wear resistance with a hard coating layer under high-speed heavy cutting conditions.
[0009]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Hydrogen content at the highest hydrogen content point
As described above, the amorphous carbon constituting the hard coating layer has the effect of improving the hardness of the layer itself, while the hydrogen has the effect of improving the strength, so that the hydrogen content is relatively high. The content point is much better, and it shows excellent chipping resistance in heavy cutting such as high cutting and high feed with large mechanical impact, but the hydrogen content accounts for the total amount with hard carbon If the ratio is less than 30 atomic% (hereinafter,% indicates atomic%), excellent strength cannot be ensured. On the other hand, if the ratio exceeds 40%, the minimum hydrogen content point having high hardness is adjacent. Even if it exists, since the hardness fall of a layer itself is unavoidable and wear comes to be accelerated as a result, the hydrogen content of the hydrogen maximum content point was determined as 30 to 40%.
[0010]
(B) Hydrogen content at the lowest hydrogen content point
As described above, the hydrogen minimum content point has the effect of remarkably improving the hardness of the layer by the relatively high content of hard carbon, but the strength of this hydrogen minimum content point is low because it has a low strength. In order to compensate for the shortage, the above-mentioned maximum hydrogen content points are alternately interposed in the thickness direction. Therefore, when the hydrogen content at the minimum hydrogen content point exceeds 10%, the layer itself has a desired high hardness. On the other hand, if the same content ratio is less than 0.1%, even if the highest hydrogen content point having high strength exists adjacently, the strength of the layer itself is inevitably lowered, and chipping occurs. Since it becomes easy, the hydrogen content of the hydrogen minimum content point was determined to be 0.1 to 10%.
[0011]
(C) Distance between the highest hydrogen content point and the lowest hydrogen content point
If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above hydrogen content ratio. As a result, it becomes impossible to ensure the desired high strength and high hardness in the layer, and the distance When the thickness exceeds 0.1 μm, the disadvantages of each point, that is, the hardness is insufficient at the highest hydrogen content point, and the strength is insufficient at the lowest hydrogen content point, and the wear progresses due to this. The distance was determined to be 0.01 to 0.1 μm because it is promoted and chipping is likely to occur.
[0012]
(D) Overall average layer thickness of the hard coating layer
If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 10 μm, chipping tends to occur at the cutting edge. It was determined to be 1 to 10 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr having an average particle diameter of 1 to 3 μm as raw material powders _Three C ₂ Powder and Co powder are prepared, and these raw material powders are blended in the blending composition shown in Table 1, wet mixed for 72 hours by a ball mill, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact is sintered in a 6 Pa vacuum at a temperature of 1400 ° C for 1 hour. After sintering, the rake face of the cutting edge is lapped to create a mirror-finished surface. Carbide substrates A-1 to A-10 having a chip shape of SPGN120308 were formed.
[0014]
Next, each of the above-mentioned superhard substrates A-1 to A-10 is ultrasonically washed in acetone and dried, and then the vapor deposition apparatus shown in FIG. A vapor deposition apparatus in which a table is provided and four targets each made of a compact of high purity carbon powder having a purity of 99.98% by mass are disposed as cathode electrodes (evaporation sources) along the outer periphery of the table. A plurality of cemented carbide substrates are mounted on the table of the apparatus so as to be able to rotate while facing the target at a predetermined distance in the radial direction from the central axis of the apparatus. Then, while maintaining the vacuum at 0.5 Pa, the inside of the apparatus was heated to 200 ° C. with a heater, and Ar gas was introduced into the apparatus to form an Ar atmosphere at a pressure of 30 Pa. In this state, rotation was performed on the table. A bias voltage of −800 V is applied to the carbide substrate to clean the surface of the carbide substrate for 20 minutes with Ar gas bombardment, and then the bias voltage applied to the carbide substrate is −50 V, and the target (cathode electrode) Glow discharge is generated on the sputtering surface portion of the cathode electrode (evaporation source) under the conditions that the sputtering power applied to each is output: 4 kW and frequency: 40 kHz, and carbon is sputtered from the cathode electrode (evaporation source). In addition, a mixed gas of Ar and hydrogen is introduced into the apparatus while the atmospheric pressure in the apparatus is always maintained at 1 Pa, and the mixing ratio of Ar and hydrogen is periodically changed, so that The target hydrogen shown in Table 2 along the layer thickness direction is formed of a hydrogen-containing amorphous carbon-based hard coating layer on the surface of the carbide substrate that rotates at An abundant hydrogen maximum content point and a hydrogen minimum content point alternately and repeatedly exist at the target intervals shown in Table 2, and from the hydrogen maximum content point to the hydrogen minimum content point, from the hydrogen minimum content point to the hydrogen. As a coated carbide tool of the present invention, a hard coating layer having a concentration distribution structure in which the hydrogen content continuously changes to the highest content point and also having a target total layer thickness similarly shown in Table 2 is formed by vapor deposition. Throw-away tips made of surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide tips) 1 to 10 were produced.
[0015]
Further, for the purpose of comparison, the cemented carbide is used under the same conditions except that the mixing ratio of Ar and hydrogen in the mixed gas of Ar and hydrogen introduced into the vapor deposition apparatus is constant from the start to the end of the hard coating layer formation. Each surface of the bases A-1 to A-10 has a target hydrogen content and a target layer thickness shown in Table 3, and consists of a hydrogen-containing amorphous carbon-based hard coating layer. A comparatively surface-coated cemented carbide throwaway tip (hereinafter referred to as a comparative coated carbide tip) equivalent to a conventional coated carbide tool is deposited by depositing a hard coating layer having substantially no change in hydrogen content along ) 1 to 10 were produced.
[0016]
Next, with the present invention coated carbide tips 1-10 and comparative coated carbide tips 1-10 screwed to the tip of the tool steel tool with a fixing jig,
Work material: Round bar of JIS A4032 (Si: 12%, Cu: 1%, Mg: 1%, Ni: 0.8%, remaining: Al, more than mass%, the same applies hereinafter),
Cutting speed: 1000 m / min. ,
Cutting depth: 8mm,
Feed: 0.4 mm / rev. ,
Cutting time: 60 minutes,
Dry continuous high-speed high-cut cutting test of Al alloy under the following conditions (cutting speed and cutting under normal conditions are 600 m / min. And 4 mm),
Work material: JIS C2100 (Zn: 5%, remaining: Cu) in the longitudinal direction with four equally spaced round bars,
Cutting speed: 800 m / min. ,
Cutting depth: 8mm,
Feed: 0.4 mm / rev. ,
Cutting time: 60 minutes,
(A cutting speed and cutting under normal conditions are 300 m / min. And 4 mm), a Cu alloy dry intermittent high speed high cutting cutting test,
Work material: JIS / ADC12 (Cu: 2.5%, Si: 10%, balance: Al) round bar,
Cutting speed: 1000 m / min. ,
Incision: 4mm,
Feed: 0.8 mm / rev. ,
Cutting time: 30 minutes,
(A cutting speed and feed under normal conditions are 600 m / min. And 0.4 mm / rev.) A dry continuous high-speed, high-feed cutting test of an Al alloy was conducted. The flank wear width was measured. In this cutting test, the service life was determined when the flank wear width reached 0.2 mm. The measurement results are shown in Tables 2 and 3.
[0017]
[Table 1]

[0018]
[Table 2]

[0019]
[Table 3]

[0020]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr _Three C ₂ Powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C (mass ratio, TiC / WC = 50/50) powder, and 1.8 μm Co powder. Each of the powders was blended into the composition shown in Table 4, further added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, and then pressed into various compacts of a predetermined shape at a pressure of 100 MPa, These green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a vacuum atmosphere of 6 Pa, kept at this temperature for 1 hour, and then subjected to furnace cooling conditions. In order to form three types of cemented carbide substrate-forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm, and further grinding from the above three types of round bar sintered bodies, In the combinations shown in Table 4, the diameter x length of the cutting edge is 6 respectively. m × 13 mm, was 10 mm × 22 mm, and the dimensions of 20 mm × 45 mm, and both the carbide substrate (end mill) B-1~B-8 with a 4 flute square shape of the twist angle of 30 degrees to produce respectively.
[0021]
Next, these carbide substrates (end mills) B-1 to B-8 were ultrasonically cleaned in acetone and dried, and the vapor deposition apparatus shown in FIG. Evaporation in which a mounting table is provided, and four targets each made of a compact of high purity carbon powder having a purity of 99.98% by mass are arranged as cathode electrodes (evaporation sources) along the outer periphery of the table. A plurality of the above-mentioned carbide substrates are mounted on the table of the apparatus at positions spaced apart from the central axis in a radial direction by a predetermined distance so as to be able to rotate while facing the target. The inside of the apparatus is heated to 200 ° C. with a heater while maintaining a vacuum of 0.5 Pa while Ar gas is introduced into the apparatus to form an Ar atmosphere at a pressure of 30 Pa. A bias voltage of −800 V is applied to the cemented carbide substrate rotating on a bull to clean the surface of the cemented carbide substrate for 20 minutes with Ar gas bombardment, and then the bias voltage applied to the cemented carbide substrate is −50 V and the target ( An arc current of 80 A is applied to each of the cathode electrodes) to generate an arc discharge, the carbon is evaporated from the cathode electrode (evaporation source) by this arc discharge, and a mixed gas of Ar and hydrogen is put into the apparatus, Introduced while the pressure of the atmosphere in the apparatus is always maintained at 3 Pa and the mixing ratio of Ar and hydrogen is periodically changed, and the surface of the carbide substrate that rotates on the table is not charged with hydrogen. The highest hydrogen content point and the lowest hydrogen content point of the target hydrogen content shown in Table 5 are alternately formed along the layer thickness direction. A concentration distribution structure that repeatedly exists at a target interval shown in FIG. 5 and in which the hydrogen content continuously changes from the highest hydrogen content point to the lowest hydrogen content point and from the lowest hydrogen content point to the highest hydrogen content point. The surface coated cemented carbide end mill of the present invention as a coated carbide tool of the present invention (hereinafter referred to as the coated carbide end mill of the present invention). 1) to 8 were produced.
[0022]
For the purpose of comparison, the above conditions are the same except that the mixing ratio of Ar and hydrogen in the mixed gas of Ar and hydrogen introduced into the vapor deposition apparatus is constant from the start to the end of the hard coating layer formation. Each of the surfaces of the hard substrates (end mills) B-1 to B-8 has a target hydrogen content and a target layer thickness shown in Table 6 and consists of a hydrogen-containing amorphous carbon-based hard coating layer. By evaporating a hard coating layer with substantially no change in hydrogen content along the layer thickness direction, a comparative surface-coated cemented carbide end mill (hereinafter referred to as a comparative coated carbide end mill) equivalent to a conventional coated carbide tool 1) to 8 were produced.
[0023]
Next, of the present invention coated carbide end mills 1-8 and comparative coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and comparative coated carbide end mills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS A2024 (Cu: 4%, Mn: 0.6%, Mg: 1.5%, balance: Al) plate material,
Cutting speed: 300 m / min. ,
Groove depth (cut): 12 mm,
Table feed: 1000 mm / min,
(Hereinafter referred to as cutting condition 1; however, cutting speed and cutting under normal conditions are 150 m / min. And 6 mm), dry high-speed, high-cut groove cutting test of Al alloy, coated carbide end mill 4 to 4 of the present invention 6 and conventional coated carbide end mills 4-6,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS AC4B (Cu: 3%, Si: 8.5%, remaining: Al) plate material,
Cutting speed: 300 m / min. ,
Groove depth (cut): 10 mm,
Table feed: 2000mm / min,
(Hereinafter referred to as cutting condition 2. However, the cutting speed and table feed under normal conditions are 150 m / min. And 1000 mm / min.) Dry high-speed, high-feed groove cutting test of Al alloy, the present invention For hard end mills 7 and 8 and comparative coated carbide end mills 7 and 8,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS C1020 (purity: 99.98% pure copper) plate material,
Cutting speed: 160 m / min. ,
Groove depth (cut): 30 mm,
Table feed: 1000 mm / min,
(Hereinafter referred to as cutting condition 3. However, the cutting speed under normal conditions is 80 m / min., The groove depth is 15 mm, and the table feed is 500 mm / min). Each of the feed groove cutting tests was performed, and the cutting groove length until the service life was measured. The service life in the above groove cutting test is evaluated by the flank wear width of the outer peripheral edge of the cutting edge, and the flank wear width is 0.1 mm in the above cutting condition 1 and in the cutting condition 2 respectively. The service life was defined as 0.2 mm and when the cutting condition 3 reached 0.1 mm. The measurement results are shown in Tables 5 and 6, respectively.
[0024]
[Table 4]

[0025]
[Table 5]

[0026]
[Table 6]

[0027]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates B-1 to B-3), 13 mm (for forming carbide substrates B-4 to B-6), and 26 mm (for carbide substrates B-). 7 and B-8)), and the diameter x length of the groove forming part is 4 mm x 13 mm (by grinding) from these three kinds of round bar sintered bodies. Carbide substrates C-1 to C-3), 8 mm × 22 mm (Carbide substrates C-4 to C-6), and 16 mm × 45 mm (Carbide substrates C-7 and C-8), and all Carbide substrates (drills) C-1 to C-8 having a two-blade shape with a twist angle of 30 degrees were produced.
[0028]
Then, the cutting edges of these carbide substrates (drills) C-1 to C-8 are subjected to honing, ultrasonically cleaned in acetone, and dried, and then loaded into the vapor deposition apparatus shown in FIG. Then, under the same conditions as in Example 2 above, the hydrogen maximum content point and the hydrogen minimum content point of the target hydrogen content shown in Table 7 along the layer thickness direction alternately at the target interval shown in Table 7 It has a concentration distribution structure that repeatedly exists and has a hydrogen content continuously changing from the highest hydrogen content point to the lowest hydrogen content point, from the lowest hydrogen content point to the lowest hydrogen content point, and also in Table 7. By depositing a hard coating layer having a target overall layer thickness shown in Fig. 1, drills made of the surface coated cemented carbide according to the present invention (hereinafter referred to as the present coated carbide drill) 1-8 as the coated carbide tool of the present invention. Each was manufactured.
[0029]
For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) C-1 to C-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. In the vapor deposition apparatus, under the same conditions as in Example 2, the target hydrogen content and target layer thickness shown in Table 8 were obtained, and the hydrogen content changed substantially along the layer thickness direction. Comparative surface-coated cemented carbide drills (hereinafter referred to as comparative coated carbide drills) 1 to 8 corresponding to conventional coated cemented carbide tools were produced by vapor-depositing no hard coating layer.
[0030]
Next, of the present invention coated carbide drills 1-8 and comparative coated carbide drills 1-8, for the present invention coated carbide drills 1-3 and comparative coated carbide drills 1-3,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS AC4B (Cu: 3%, Si: 8.5%, remaining: Al) plate material,
Cutting speed: 200 m / min. ,
Feed: 0.6mm / rev,
Hole depth: 10mm,
(Hereinafter referred to as cutting condition 1. However, the cutting speed and feed under normal conditions are 80 m / min. And 0.2 mm / rev.) Wet high-speed high-feed drilling test of Al alloy, the present invention For coated carbide drills 4-6 and comparative coated carbide drills 4-6,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS C2100 (Zn: 5%, remaining: Cu) plate material,
Cutting speed: 200 m / min. ,
Feed: 0.6mm / rev,
Hole depth: 16mm,
(Hereinafter referred to as cutting condition 2; however, the cutting speed and feed under normal conditions are 90 m / min. And 0.3 mm / rev.) For coated carbide drills 7 and 8 and comparative coated carbide drills 7 and 8,
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS A4032 (Si: 12%, Cu: 1%, Mg: 1%, Ni: 0.8%, balance: Al),
Cutting speed: 250 m / min. ,
Feed: 0.7mm / rev,
Hole depth: 40mm,
(Hereinafter referred to as cutting condition 3; however, the cutting speed and feed under normal conditions are 110 m / min. And 0.3 mm / rev.) In all wet drilling cutting tests (using water-soluble cutting oil), the number of drilling processes up to the end of the service life was measured. The service life in the wet drilling cutting test is evaluated by the flank wear width of the tip cutting edge surface, and the flank wear width is 0.3 mm under the above cutting condition 1 and 0 under the above cutting condition 2. .2 mm and when the cutting condition 3 reached 0.2 mm, the service life was determined. The measurement results are shown in Tables 7 and 8, respectively.
[0031]
[Table 7]

[0032]
[Table 8]

[0033]
As a result, the coated carbide tips 1 to 10 of the present invention, the coated carbide end mills 1 to 8 of the present invention, the coated carbide drills 1 to 8 of the present invention, and the conventionally coated carbide tools of the present invention. For the hard coating layers constituting the comparative coated carbide tips 1 to 10, the comparative coated carbide end mills 1 to 8, and the comparative coated carbide drills 1 to 8, the hydrogen content is increased along the thickness direction with a high frequency glow. As measured using a discharge spectroscopic analyzer, in the hard coating layer of the coated carbide tool of the present invention, the hydrogen maximum content point and the hydrogen minimum content point alternate with the hydrogen content and the interval substantially the same as the target value, respectively. And a concentration distribution structure in which the hydrogen content continuously changes from the highest hydrogen content point to the lowest hydrogen content point and from the lowest hydrogen content point to the highest hydrogen content point. Furthermore the average layer thickness of the hard layer showed entire target layer thickness substantially the same value. On the other hand, the hard coating layer of the conventional coated carbide tool has a hydrogen content that is substantially the same as the target hydrogen content and an overall average layer thickness that is substantially the same as the target overall layer thickness. There was no change in the hydrogen content, indicating a homogeneous hydrogen content throughout the layer.
[0034]
【The invention's effect】
From the results shown in Tables 2 to 8, the hard coating layer has a maximum hydrogen content point having excellent strength and a minimum hydrogen content point having high hardness repeatedly in the layer thickness direction at predetermined intervals. The present invention coated carbide tool having a concentration distribution structure in which the hydrogen content continuously changes from the highest hydrogen content point to the lowest hydrogen content point, from the lowest hydrogen content point to the highest hydrogen content point, Even when cutting various materials, especially Al alloy and Cu alloy under high-speed heavy conditions, the hard coating layer exhibits excellent strength due to the highest hydrogen content point, and the hard coating layer In contrast to the fact that chipping is suppressed and that the layer itself has a remarkably high hardness due to the above-mentioned minimum hydrogen content of hard carbon, it exhibits excellent wear resistance. Along the layer thickness direction In the conventional coated carbide tool (comparative coated carbide tool) formed by vapor-depositing a hard coating layer that does not substantially change the hydrogen content, the hydrogen content of the hard coating layer is increased under high-speed heavy cutting conditions. The strength of the hard coating layer increases proportionally, but since the hardness decreases, the progress of wear is accelerated, while the hard coating layer has a lower hydrogen content, the hard coating layer Although the hardness of the layer increases proportionally, since the strength decreases, chipping is likely to occur, and it is clear that in any case, the service life is reached in a relatively short time.
As described above, the coated carbide tool of the present invention is capable of cutting various work materials, in particular, work materials such as Al alloy and Cu alloy, at high speed, as well as cutting under normal conditions. And even when performed under heavy cutting conditions such as high cutting and high feed with large mechanical impact, the hard coating layer exhibits excellent wear resistance without chipping on the cutting edge, It can fully satisfy the labor-saving and energy-saving of cutting, and also the cost reduction.
[Brief description of the drawings]
FIG. 1 shows a vapor deposition apparatus to which a sputtering apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention is applied, (a) is a schematic plan view, and (b) is a schematic front view. is there.
FIG. 2 shows a vapor deposition apparatus to which an arc ion plating apparatus used for forming a hard coating layer constituting the coated carbide tool of the present invention is applied, (a) is a schematic plan view, and (b) is a schematic plan view. It is a front view.

Claims (1)

In the surface-coated cemented carbide cutting tool formed by vapor-depositing an amorphous carbon-based hard coating layer containing hydrogen on the surface of the tungsten carbide-based cemented carbide substrate with an overall average layer thickness of 1 to 10 μm,
In the amorphous carbon-based hard coating layer, the hydrogen maximum content point and the hydrogen minimum content point are alternately present at predetermined intervals along the layer thickness direction, and the hydrogen minimum content point is from the hydrogen maximum content point. Containing point, having a concentration distribution structure in which the hydrogen content continuously changes from the hydrogen minimum content point to the hydrogen maximum content point,
Furthermore, the hydrogen content at the hydrogen maximum content point is 30 to 40 atomic% in the proportion of the total amount with carbon,
The hydrogen content at the minimum hydrogen content point is 0.1 to 10 atomic% as a percentage of the total amount with carbon,
And the distance between the adjacent highest hydrogen content point and the lowest hydrogen content point is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under high-speed heavy cutting conditions.

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