JP4379908B2 - Cutting tool made of surface-coated cemented carbide that exhibits excellent chipping resistance with a hard coating layer in high-speed heavy cutting - Google Patents

Description

【００２０】
【表２】

【００２１】
【表３】

【００２２】
【表４】

【００２３】
【表５】

【００２４】
【表６】

【００２５】
（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７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７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）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２６】
ついで、これらの超硬基体（エンドミル）Ｃ−１〜Ｃ−８の表面をアセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示される物理蒸着装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表８に示される目標組成のＣｒ最高含有点とＢ最高含有点とが交互に同じく表８に示される目標間隔で繰り返し存在し、かつ前記Ｂ最高含有点から前記Ｃｒ最高含有点、前記Ｃｒ最高含有点から前記Ｂ最高含有点へＣｒおよびＢ成分の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表８に示される目標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。
【００２７】
また、比較の目的で、上記の超硬基体（エンドミル）Ｃ−１〜Ｃ−８の表面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に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表９に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｃｒ，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製エンドミル（以下、従来被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２８】
つぎに、上記本発明被覆超硬エンドミル１〜８および従来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および従来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・Ｓ１５Ｃの板材、
切削速度：１１０ｍ／ｍｉｎ．、
軸方向切り込み：５ｍｍ、
径方向切り込み：２．５ｍｍ、
テーブル送り：３８０ｍｍ／分、
の条件での軟鋼の乾式高速高切り込み側面切削加工試験、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・ＳＵＳ３０４の板材、
切削速度：１２０ｍ／ｍｉｎ．、
軸方向切り込み：１０ｍｍ、
径方向切り込み：３．５ｍｍ、
テーブル送り：５００ｍｍ／分、
の条件でのステンレス鋼の乾式高速高切り込み側面切削加工試験、本発明被覆超硬エンドミル７，８および従来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・ＳＵＳ４３０の板材、
切削速度：１２０ｍ／ｍｉｎ．、
軸方向切り込み：２０ｍｍ、
径方向切り込み：４ｍｍ、
テーブル送り：３５０ｍｍ／分、
の条件でのステンレス鋼の乾式高速高送り側面切削加工試験をそれぞれ行い、いずれの側面切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表８、９にそれぞれ示した。
【００２９】
【表７】

【００３０】
【表８】

【００３１】
【表９】

【００３２】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−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Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−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）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３３】
ついで、これらの超硬基体（ドリル）Ｄ−１〜Ｄ−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１の物理蒸着装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表１０に示される目標組成のＣｒ最高含有点とＢ最高含有点とが交互に同じく表１０に示される目標間隔で繰り返し存在し、かつ前記Ｂ最高含有点から前記Ｃｒ最高含有点、前記Ｃｒ最高含有点から前記Ｂ最高含有点へＣｒおよびＢ成分の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表１０に示される目標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。
【００３４】
また、比較の目的で、上記の超硬基体（ドリル）Ｄ−１〜Ｄ−８の表面に、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のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１１に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｃｒ，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製ドリル（以下、従来被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３５】
つぎに、上記本発明被覆超硬ドリル１〜８および従来被覆超硬ドリル１〜８のうち、本発明被覆超硬ドリル１〜３および従来被覆超硬ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３０４の板材、
切削速度：６０ｍ／ｍｉｎ．、
送り：０．２ｍｍ／ｒｅｖ．、
穴深さ：１５ｍｍ．、
の条件でのステンレス鋼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および従来被覆超硬ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：７５ｍ／ｍｉｎ．、
送り：０．２３ｍｍ／ｒｅｖ．、
穴深さ：２５ｍｍ．、
の条件での軟鋼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および従来被覆超硬ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ４３０の板材、
切削速度：１００ｍ／ｍｉｎ．、
送り：０．３５ｍｍ／ｒｅｖ。、
穴深さ：５０ｍｍ．、
の条件でのステンレス鋼の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速高送り穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表１０、１１にそれぞれ示した。
【００３６】
【表１０】

【００３７】
【表１１】

【００３８】
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１〜１６、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を構成する硬質被覆層におけるＣｒ最高含有点とＢ最高含有点の組成、並びに従来被覆超硬工具としての従来被覆超硬チップ１〜１６、従来被覆超硬エンドミル１〜８、および従来被覆超硬ドリル１〜８の硬質被覆層の組成について、厚さ方向に沿ってＣｒ、Ｂ、およびＺｒ成分の含有量をオージェ分光分析装置を用いて測定したところ、本発明被覆超硬工具の硬質被覆層では、Ｃｒ最高含有点とＢ最高含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記Ｃｒ最高含有点から前記Ｂ最高含有点、前記Ｂ最高含有点から前記Ｃｒ最高含有点へＣｒおよびＢ成分の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有することが確認され、また硬質被覆層の平均層厚も目標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厚さ方向に沿って組成変化が見られず、かつ目標組成と実質的に同じ組成および目標層厚と実質的に同じ平均層厚を示すことが確認された。
【００３９】
【発明の効果】
表３〜１１に示される結果から、硬質被覆層が厚さ方向に、きわめて高い高温強度を有するＣｒ最高含有点とすぐれた高温硬さを有するＢ最高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Ｃｒ最高含有点から前記Ｂ最高含有点、前記Ｂ最高含有点から前記Ｃｒ最高含有点へＣｒおよびＢ成分の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有する本発明被覆超硬工具は、いずれも各種のステンレス鋼や軟鋼の高速切削加工を、高い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、切刃部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のに対して、硬質被覆層が厚さ方向に沿って実質的に組成変化のない（Ｃｒ，Ｂ）Ｎ層からなる従来被覆超硬工具においては、重切削条件での高速切削加工では、前記硬質被覆層の高温強度および高温硬さ不足が原因で、いずれもチッピングが発生し、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、通常の条件での鋼や鋳鉄などの切削加工は勿論のこと、特に各種のステンレス鋼や軟鋼などの難削材の高速切削加工を、高い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、すぐれた耐チッピング性を示し、長期に亘ってすぐれた耐摩耗性を発揮するものであるから、切削加工装置の高性能化、並びに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る物理蒸着装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来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るアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
In the present invention, the hard coating layer has excellent high-temperature strength and also has high high-temperature hardness, and therefore, particularly, cutting of difficult-to-cut materials such as various high-viscosity stainless steels and mild steels, particularly at high speed, A surface-coated cemented carbide that provides excellent wear resistance without causing chipping (microchips) in the hard coating layer when subjected to heavy cutting conditions such as high cutting and high feed with high mechanical impact. The present invention relates to a cutting tool (hereinafter referred to as a coated carbide tool).
[0002]
[Prior art]
Generally, for coated carbide tools, a throw-away tip that is attached to the tip of a cutting tool for turning or flattening of various steel and cast iron work materials, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). On the surface)
Composition formula: (Cr _{1- M} B _M ) N (however, in atomic ratio, M represents 0.40 to 0.60),
Coated carbide tools formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Cr and B satisfying the following [hereinafter referred to as (Cr, B) N] with an average layer thickness of 0.5 to 15 μm are known. In this coated carbide tool, the (Cr, B) N layer, which is a hard coating layer, has a high temperature strength due to the Cr component and a high temperature hardness due to the B component. It is also well known that it is used for cutting and intermittent cutting (for example, see Patent Document 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Cr—B alloy having various compositions is set, for example, at a current of 100 A, while being heated to a temperature of 500 ° C. At the same time, a mixed gas of Ar gas and nitrogen gas (in volume%, Ar: 70%, N ₂ : 30%) is introduced into the apparatus as a reaction gas, for example, a reaction atmosphere of 2.5 Pa, while For example, a hard coating layer made of a (Cr, B) N layer is vapor-deposited on the surface of the cemented carbide substrate with an average layer thickness of 0.5 to 15 μm under the condition that a bias voltage of −100 V is applied, for example. Manufactured by It is also known that.
[0005]
[Patent Document 1]
JP-A-56-41372 [0006]
[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 and energy saving and further cost reduction for cutting. Although cutting tends to be forced under heavy cutting conditions such as high feed, in the conventional coated carbide tool in which the hard coating layer is a (Cr, B) N layer, this is applied to various types of high viscosity, for example. When used to cut difficult-to-cut materials such as stainless steel and mild steel under heavy cutting conditions such as high cutting and high feed with particularly high mechanical impact, (Cr, B) Since the high-temperature strength and high-temperature hardness of the N layer are insufficient, chipping (small chipping) is likely to occur at the cutting edge and the wear of the hard coating layer is promoted. The service life is reached in time Is Jo.
[0007]
[Means for Solving the Problems]
In view of the above, the inventors of the present invention, from the above viewpoint, have a coating super-superior that exhibits excellent chipping resistance in a high-speed heavy cutting of difficult-to-cut materials such as various highly viscous stainless steels and mild steels. As a result of conducting research, focusing on the hard coating layer that constitutes the above-mentioned conventional coated carbide tool in order to develop a hard tool,
(A) For example, a physical vapor deposition apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A B—Cr—Zr alloy having a relatively high B content on one side and a Cr—B—Zr alloy having a relatively high Cr content on the other side as a sputtering target because the conductivity is small. Therefore, using the devices facing each other as the cathode electrode target because they have electrical conductivity, the carbide substrate is mounted on the rotary table of the device eccentrically at a position radially away from the central axis of the rotary table. In this state, the reaction atmosphere in the apparatus is changed to a nitrogen atmosphere (practically a mixed gas atmosphere of Ar and nitrogen), the rotary table is rotated, and the thickness of the hard coating layer formed by vapor deposition is uniform. From the sputtering target of the B-Cr-Zr alloy having a relatively high B content, for example, Ar ions are used to sputter B-Cr-Zr ions while rotating the cemented carbide substrate itself for the purpose of achieving the above. At the same time, an arc discharge is generated between the cathode electrode target and the anode electrode of the Cr-B-Zr alloy having a relatively high Cr content to release Cr-B-Zr ions, thereby When a composite nitride of Cr, B, and Zr [hereinafter referred to as (Cr, B, Zr) N] layer is formed on the surface of the hard substrate, the resulting (Cr, B, Zr) N layer has a rotating table. The highest B content point is formed in the layer when the carbide substrate arranged in a ring shape is closest to the sputtering target of the B-Cr-Zr alloy having a relatively high B content on one side. The In addition, when the cemented carbide substrate is closest to the cathode electrode of the Cr—B—Zr alloy having a relatively high Cr content on the other side, the highest Cr content point is formed in the layer. By rotation, the B highest content point and the Cr highest content point alternately appear at predetermined intervals in the layer thickness direction, and from the B highest content point, the Cr highest content point, from the Cr highest content point. It has a component concentration distribution structure in which the content ratios of Cr and B components continuously change to the B highest content point.
[0008]
(B) In the (Cr, B, Zr) N layer having the repeated continuous change component concentration distribution structure of (a) above, for example, the respective compositions of the sputtering target and the cathode electrode target arranged oppositely are prepared, and the carbide substrate is By controlling the rotation speed of the mounted rotary table,
The B highest content point is the composition formula: [B _{1− (X + Z)} Cr _X Zr _Z] N (provided that an atomic ratio, X is 0.15 to 0.40, Z represents a 0.01-0.10)
The Cr maximum content point is the composition formula: [Cr _{1− ( Y + Z)} B _Y Zr _Z ] N (wherein Y is 0.05 to 0.40 and Z is 0.01 to 0.10 in atomic ratio _). ),
And the distance in the thickness direction of the adjacent B highest content point and Cr highest content point adjacent to each other is 0.01 to 0.1 μm,
In the above B highest content point portion, the B content in the (Cr, B, Zr) N layer is relatively high and the Cr content is low, so it shows a higher high temperature hardness, while the above Cr highest content In the point portion, since the B content is low and the Cr content is high compared to the B highest content point portion, a relatively high high temperature strength is secured, and this high temperature strength is obtained by the coexistence of the Zr component. Since the distance between the highest B content point and the highest Cr content point is extremely small, the entire layer has a very high high-temperature strength and high high-temperature hardness. Coated carbide tools composed of (Cr, B, Zr) N layers with a high-speed heavy cutting of difficult-to-cut materials such as various types of stainless steel and mild steel, as well as various types of steel and cast iron Chip by processing Without the occurrence of bridging, and superior to become to exert a long term wear resistance was.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made on the basis of the above research results. A hard coating layer made of (Cr, B, Zr) N is physically applied on the surface of a cemented carbide substrate with an average layer thickness of 0.5 to 15 μm. In coated carbide tools formed by vapor deposition,
In the hard coating layer, the highest B content point and the highest Cr content point are alternately present at predetermined intervals along the layer thickness direction, and the highest Cr content point, Cr A component concentration distribution structure in which the content ratios of Cr and B components continuously change from the highest content point to the B highest content point, respectively,
Further, the B highest content point is the composition formula: [B _{1− (X + Z)} Cr _X Zr _Z] N (provided that an atomic ratio, X is 0.15 to 0.40, Z represents a 0.01-0.10)
The Cr maximum content point, composition formula: _{formula: [Cr 1- (Y + Z} ) B Y Zr Z] ( however, in atomic ratio, Y is 0.05 to 0.40, Z is from 0.01 to 0 .10),
And the distance between the B highest content point and the Cr highest content point adjacent to each other is 0.01 to 0.1 μm.
It is characterized by a coated carbide tool that exhibits excellent chipping resistance with a hard coating layer in high-speed heavy cutting.
[0010]
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) In the composition (Cr, B, Zr) N layer with the highest B content point, the Cr component has the effect of improving the high temperature strength, and the Zr component also has the effect of further improving the high temperature strength in the presence of the Cr component. On the other hand, the B component has an effect of improving the high-temperature hardness. Therefore, at the highest B content point, the content of the B component is relatively increased to ensure a further excellent high-temperature hardness. When the X value indicating the content ratio of the component is less than 0.15 in the proportion of the total amount of B and Zr components (atomic ratio, the same applies hereinafter), the proportion of the B component becomes excessive and embrittles. Even if there is an adjacent Cr highest content point with excellent high-temperature strength, the highest B content point is the starting point of fracture, and chipping is likely to occur. On the other hand, if the X value exceeds 0.40, The ratio of B component is too low, There lowered, since it becomes wear proceeds rapidly, the X value was defined as 0.15 to 0.40.
The Zr component has the effect of improving the high-temperature strength in the coexistence with the Cr component as described above, but the Z value indicating the content ratio of the Zr component is 0. 0 in the total amount of the Cr and B components. If it is less than 01, the desired high-temperature strength improvement effect cannot be obtained. On the other hand, if the Z value exceeds 0.10, the high-temperature hardness rapidly decreases and wear is promoted. It was determined as 01 to 0.10.
[0011]
(B) Composition of the highest Cr content point As described above, the highest B content point has excellent high-temperature hardness, but on the other hand, it has a low high-temperature strength. For the purpose, the Cr content is high and the Zr component coexists, thereby interposing in the thickness direction alternately the highest Cr content points that have high high-temperature strength. When the Y value indicating the ratio is less than 0.05 in the ratio of the total amount of Cr and Zr components, the ratio of the Cr components increases too much, the high temperature hardness decreases rapidly, and the B highest content point is adjacent. Even if it is present, wear is further promoted. On the other hand, if the Y value exceeds 0.40 as a proportion of the total amount of Cr and Zr components, the high-temperature strength at the highest Cr content point rapidly decreases. Since chipping is likely to occur, The case was determined to be 0.05 to 0.40.
Further, the Z value indicating the content ratio of the Zr component at the highest Cr content point is also determined to be 0.01 to 0.10 for the same reason as that at the highest B content point.
[0012]
(C) Interval between the highest B content point and the highest Cr content point If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. Strength and high-temperature hardness cannot be ensured, and if the distance exceeds 0.1 μm, each point has a defect, that is, if the B highest content point is insufficient, the high temperature strength is insufficient, and if the Cr highest content point is high Insufficient hardness appears locally in the layer, which makes it easier for chipping to occur at the cutting edge and promotes wear, so the interval is set to 0.01 to 0.1 μm. It was.
[0013]
(D) Average layer thickness of hard coating layer If the layer thickness is less than 0.5 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping occurs at the cutting edge. Since it becomes easy to generate | occur | produce, the average layer thickness was set to 0.5-15 micrometers.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, TaC powder, VC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. And then wet-mixed with a ball mill for 72 hours, dried, and press-molded into a green compact at a pressure of 100 MPa. The green compact was vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under holding conditions, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and a cemented carbide substrate A-1 made of WC-based cemented carbide having a chip shape of ISO standard / CNMG120408 ~ A-10 was formed.
[0015]
Further, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / TiCN-based cermet carbide substrates B-1 to B-6 having a chip shape of CNMG120408 were formed.
[0016]
Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then rotated in the physical vapor deposition apparatus shown in FIG. On the table, it is mounted eccentrically at a position away from the central axis of the rotary table in the radial direction, and as a cathode electrode target (evaporation source) on one side, Cr— B-Zr alloy, as a sputtering target (evaporation source) on the other side, B-Cr-Zr alloy for forming B highest content point having various component compositions are arranged opposite to each other across the rotary table, and for bombard cleaning. Carbide substrate, which is also mounted with metal Cr, and is first heated to 500 ° C. with a heater and then rotated while rotating on the rotary table while evacuating the apparatus and maintaining a vacuum of 0.1 Pa or less. A DC bias voltage of −1000 V is applied, a current of 100 A is caused to flow between the metal Cr of the cathode electrode and the anode electrode to generate arc discharge, and the surface of the carbide substrate is cleaned with Cr bombardment, and then in the apparatus. As a reaction gas, a mixed gas of nitrogen gas and Ar gas (volume%, N ₂ / Ar = 30/70) is introduced to make a reaction atmosphere of 2.5 Pa, and rotates while rotating on the rotary table. A DC bias voltage of −100 V is applied to the carbide substrate, and an arc discharge is generated by flowing a current of 100 A between the cathode electrode target and the anode electrode of the Cr—B—Zr alloy for forming the highest Cr content point. In addition, the sputtering target of the B-Cr-Zr alloy for forming the highest B content point is applied with a power of 1 kW to generate spatter. The highest Cr content point and the highest B content point of the target composition shown in Tables 3 and 4 are alternately repeated at the target intervals shown in Tables 3 and 4 along the layer thickness direction on the surface of the cemented carbide substrate. And a component concentration distribution structure in which the content ratios of Cr and B components continuously change from the highest B content point to the highest Cr content point, from the highest Cr content point to the highest B content point, and Similarly, by depositing a hard coating layer having a target layer thickness shown in Tables 3 and 4, a throwaway tip made of the surface-coated cemented carbide of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the coated carbide chip of the present invention). 1) to 16 were produced.
[0017]
For comparison purposes, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, and each of the ordinary arcs shown in FIG. Inserted into an ion plating apparatus, mounted with a Cr—B alloy having various component compositions as a cathode electrode (evaporation source), and mounted with a metallic Cr for bombard cleaning. The inside of the apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, and then a −1000 V DC bias voltage was applied to the cemented carbide substrate, and between the metal Cr of the cathode electrode and the anode electrode by flowing a 100A current to generate an arc discharge, with the carbide substrate surface was washed Cr bombardment by then a mixed gas (volume% of nitrogen gas and Ar gas as a reaction gas into the apparatus, N 2 _/ Ar = 0/70) was introduced to make a reaction atmosphere of 2.5 Pa, and the bias voltage applied to the cemented carbide substrate was lowered to −100 V to generate an arc discharge between the cathode electrode and the anode electrode, Therefore, each of the surfaces of the carbide substrates A-1 to A-10 and B-1 to B-6 has the target composition and the target layer thickness shown in Table 5 and is substantially along the thickness direction. By depositing a hard coating layer composed of a (Cr, B) N layer having no composition change, a conventional surface-coated cemented carbide throwaway tip (hereinafter referred to as a conventional coated carbide tip) as a conventional coated carbide tool. ) 1-16 were produced.
[0018]
Next, with the present invention coated carbide tips 1-16 and conventional coated carbide tips 1-16, in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / S15C lengthwise equal length 4 vertical grooved round bars,
Cutting speed: 260 m / min. ,
Cutting depth: 2.8 mm,
Feed: 0.12 mm / rev. ,
Cutting time: 4 minutes
Dry intermittent high-speed high-cut cutting test of mild steel under the conditions of
Work material: JIS / SUS316 lengthwise equidistant 4 round grooved round bars,
Cutting speed: 250 m / min. ,
Incision: 2.5mm,
Feed: 0.20 mm / rev. ,
Cutting time: 3 minutes
Stainless steel dry interrupted high-speed high-cut cutting test,
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 250 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.4 mm / rev. ,
Cutting time: 3 minutes
The dry intermittent high-speed high-feed cutting test of stainless steel was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any of the turning tests. The measurement results are shown in Table 6.
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
[Table 3]

[0022]
[Table 4]

[0023]
[Table 5]

[0024]
[Table 6]

[0025]
(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 ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, and 1 Prepare 8 .mu.m Co powder, mix these raw material powders with the composition shown in Table 7, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and then press at a pressure of 100 MPa. The green compacts were press-molded, and 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 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions Three types of sintered carbide rod forming bodies for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of round rod sintered bodies described above were subjected to grinding and shown in Table 7. In combination, a carbide substrate (end mill) having a diameter of 4 mm × 13 mm, a length of 6 mm × 13 mm, a size of 10 mm × 22 mm, and a size of 20 mm × 45 mm, and a four-blade square with a twist angle of 30 degrees. ) C-1 to C-8 were produced.
[0026]
Next, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the physical vapor deposition apparatus shown in FIG. 1, the highest Cr content point and the highest B content point of the target composition shown in Table 8 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 8, and the B It has a component concentration distribution structure in which the content ratios of Cr and B components continuously change from the highest content point to the highest Cr content point and from the highest Cr content point to the highest B content point, and also shown in Table 8 The surface coating cemented carbide end mills (hereinafter referred to as the present invention coated carbide end mills) 1 to 8 as the present invention coated carbide tools were produced by vapor-depositing a hard coating layer having a target layer thickness. .
[0027]
For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. (Cr, B) N layer that is charged and has the target composition and target layer thickness shown in Table 9 under the same conditions as in Example 1 and has substantially no composition change along the layer thickness direction. The conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated cemented carbide end mills) 1 to 8 as conventional coated cemented carbide tools were produced by vapor-depositing a hard coating layer comprising:
[0028]
Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 110 m / min. ,
Axial cut: 5mm,
Radial notch: 2.5mm,
Table feed: 380 mm / min,
With respect to the dry high-speed high-cut side cutting test of mild steel under the following conditions, the coated carbide end mills 4 to 6 of the present invention and the conventional coated carbide end mills 4 to 6:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 120 m / min. ,
Axial cut: 10 mm
Radial notch: 3.5mm,
Table feed: 500 mm / min,
For the dry high-speed high-cut side cutting test of stainless steel under the following conditions, the coated carbide end mills 7 and 8 of the present invention and the conventional coated carbide end mills 7 and 8:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS430 plate material,
Cutting speed: 120 m / min. ,
Axial cut: 20mm,
Radial notch: 4mm,
Table feed: 350 mm / min,
Stainless steel dry high-speed high-feed side-cutting tests were performed under the conditions described above, and the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life in any side-cutting test. The cutting length up to was measured. The measurement results are shown in Tables 8 and 9, respectively.
[0029]
[Table 7]

[0030]
[Table 8]

[0031]
[Table 9]

[0032]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Carbide substrates (drills) D-1 to D-8 having a two-blade shape with a twist angle of 30 degrees were manufactured.
[0033]
Next, honing is applied to the cutting edges of these carbide substrates (drills) D-1 to D-8, ultrasonic cleaning is performed in acetone, and the dried blades are loaded into the physical vapor deposition apparatus of FIG. Under the same conditions as in Example 1 above, the highest Cr content point and the highest B content point of the target composition shown in Table 10 along the layer thickness direction are repeatedly present at the target interval shown in Table 10 alternately. And having a component concentration distribution structure in which the content ratios of Cr and B components continuously change from the highest B content point to the highest Cr content point, from the highest Cr content point to the highest B content point, respectively, By depositing a hard coating layer having a target layer thickness shown in Table 10, drills made of the surface coated cemented carbide according to the present invention (hereinafter referred to as the present coated carbide drill) 1 to 8 as the coated carbide tool of the present invention. Were manufactured respectively.
[0034]
For comparison purposes, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and the arc ion plate of FIG. And having the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1, and substantially no composition change along the layer thickness direction (Cr, B ) Drills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools were produced by vapor-depositing a hard coating layer comprising an N layer.
[0035]
Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8, the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 60 m / min. ,
Feed: 0.2 mm / rev. ,
Hole depth: 15 mm. ,
For the wet high speed high feed drilling test of stainless steel under the conditions of the present invention, the coated carbide drills 4-6 of the present invention and the conventional coated carbide drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 75 m / min. ,
Feed: 0.23 mm / rev. ,
Hole depth: 25 mm. ,
For the wet high speed high feed drilling test of mild steel under the following conditions, the coated carbide drills 7 and 8 of the present invention and the conventional coated carbide drills 7 and 8:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS430 plate material,
Cutting speed: 100 m / min. ,
Feed: 0.35 mm / rev. ,
Hole depth: 50 mm. ,
Wet high-speed high-feed drilling machining test of stainless steel under the above conditions, respectively, and the flank wear width of the tip cutting edge surface is 0 in any wet high-speed high-feed drilling test (using water-soluble cutting oil). The number of drilling processes up to 3 mm was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0036]
[Table 10]

[0037]
[Table 11]

[0038]
In the hard coating layer which comprises this invention coated carbide tips 1-16, this invention coated carbide end mills 1-8, and this invention coated carbide drills 1-8 as this invention coated carbide tool obtained as a result. The composition of the highest Cr content point and the highest B content point, as well as the conventional coated carbide tips 1-16 as the conventional coated carbide tool, the conventional coated carbide end mills 1-8, and the hard coating of the conventional coated carbide drills 1-8 Regarding the composition of the layer, the content of Cr, B, and Zr components along the thickness direction was measured using an Auger spectroscopic analyzer. In the hard coating layer of the coated carbide tool of the present invention, The highest B content points are alternately and repeatedly present at substantially the same composition and interval as the target value, and the highest Cr content point to the highest B content point and the highest B content point to the highest Cr content point Cr And The content of component B is confirmed to have each continuously varying component concentration distribution structure, and exhibited substantially the same value average layer thickness is also the target layer thickness of the hard layer.
On the other hand, the hard coating layer of the conventional coated carbide tool does not show a composition change along the thickness direction, and shows a composition substantially the same as the target composition and an average layer thickness substantially the same as the target layer thickness. confirmed.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 11, in the thickness direction, the hardest coating layer has a Cr highest content point having extremely high high-temperature strength and a B highest content point having excellent high-temperature hardness at predetermined intervals alternately. A book having a component concentration distribution structure that repeatedly exists and the content ratio of Cr and B components continuously changes from the highest Cr content point to the highest B content point and from the highest B content point to the highest Cr content point. Invented coated carbide tools all have high-speed cutting of various types of stainless steel and mild steel, even when heavy cutting conditions such as high cutting with high mechanical impact and high cutting are performed, and chipping is applied to the cutting edge. Conventionally coated carbide consisting of (Cr, B) N layer, which does not occur and the hard coating layer exhibits excellent wear resistance, while the hard coating layer has substantially no composition change along the thickness direction. For tools, heavy The high-speed cutting at cutting conditions, in high temperature strength and high-temperature hardness insufficient cause of the hard coating layer, any chipping occurs, it is apparent that lead to a relatively short time service life.
As described above, the coated carbide tool of the present invention is not only capable of cutting steel and cast iron under normal conditions, but particularly high-speed cutting of difficult-to-cut materials such as various stainless steels and mild steels. A cutting device that exhibits excellent chipping resistance and excellent wear resistance over a long period of time even under heavy cutting conditions such as high cutting and high feed with mechanical impact. It is possible to sufficiently satisfy the high performance, cutting labor and energy saving, and cost reduction.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows a physical vapor deposition apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of an arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.

Claims (1)

On the surface of a tungsten carbide base cemented carbide substrate or a titanium carbonitride cermet substrate, a hard coating layer made of a composite nitride of Cr (chromium), B (boron) and Zr (zirconium) is an average layer of 0.5 to 15 μm. A surface-coated cemented carbide cutting tool made by physical vapor deposition with a thickness,
In the hard coating layer, the highest B content point and the highest Cr content point are alternately present at predetermined intervals along the layer thickness direction, and the highest Cr content point, Cr A component concentration distribution structure in which the content ratios of the B and Cr components continuously change from the highest content point to the B highest content point, respectively,
Further, the B highest content point is the composition formula: [B _{1− (X + Z)} Cr _X Zr _Z] N (provided that an atomic ratio, X is 0.15 to 0.40, Z represents a 0.01-0.10)
The Cr maximum content point is the composition formula: [Cr _{1− ( Y + Z)} B _Y Zr _Z ] N (wherein Y is 0.05 to 0.40 and Z is 0.01 to 0.10 in atomic ratio _). ),
And the distance between the B highest content point and the Cr highest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance in a high-speed heavy-cutting process with a hard coating layer.

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