JPH1158105A - Covered cemented carbide tool for high speed-high feed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool excellent in heat resistance and plastic deformation resistance at cutting time by setting it to a specific high speed high-feed adaptive index. SOLUTION: This covered cemented carbide tool for high speed-high feed is formed by covering cemented carbide mainly composed of WC and Fe group metal with a monolayer or multilayer hard coating film on which hardness of a coating film of at least a single layer is not less than HV 2,000 A high speed-high feed adaptive index HVF of this tool is set not less than 2.3. Here, [HVF= (HC-200)/200}×(HRA-5)/85}× 6/(M+6)}×CR] is relaized, where HVF respresents a high speed-high feed adaptive index, and HC represents coercive force (Oe) of the cemented carbide. HRA represents hardness (a Rockwell A scale) of the cemented carbide, and M represents an Fe group metal quantity (wt.%) of the cemented carbided, and CR represents crack resistance (kgf/mm) of the cemented carbide.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本願発明は、切削用途に供する超
硬合金材料で、近年の傾向である高硬度金型材を効率よ
く切削加工するための高速高送り用被覆超硬工具に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated carbide tool for high-speed and high-feed, which is a cemented carbide material used for cutting and is used for efficiently cutting a high-hardness mold material, which is a recent trend.

【０００２】[0002]

【従来の技術】高速高送り用被覆超硬工具は切削用工具
として広く使用されており、特に金型切削加工分野にお
いてはエンドミルなどの回転工具の使用が頻繁である。
ここでの工具の回転数は高々１０、０００ｒｐｍ、テー
ブル送り量は高々５００ｍｍ／分程度である。ところが
近年、高速マシンと称する超高速スピンドルを装備した
工作機械が出現し始めた。例えば５０、０００ｒｐｍを
超える工作機械も出現し始めている。これによって回転
工具の使用条件をさらなる高速高送りへ移行させる試み
が盛んに行われている。工具回転数を飛躍的に上げると
一刃当たりの送り量を増加させることなく、いやむしろ
一刃当たりの送り量を減少せしめ、代りにテーブル送り
量を飛躍的に増大させ、切削の高能率化をめざす意図で
ある。2. Description of the Related Art Coated carbide tools for high speed and high feed are widely used as cutting tools. In particular, in the field of die cutting, a rotating tool such as an end mill is frequently used.
Here, the rotational speed of the tool is at most 10,000 rpm, and the table feed amount is at most about 500 mm / min. However, in recent years, machine tools equipped with an ultra-high-speed spindle called a high-speed machine have begun to appear. For example, machine tools exceeding 50,000 rpm have also begun to appear. As a result, attempts have been actively made to shift the operating conditions of the rotary tool to higher speeds and higher feeds. If the number of revolutions of the tool is dramatically increased, the amount of feed per tooth will not be increased, but rather the amount of feed per tooth will be reduced.Instead, the amount of table feed will be dramatically increased, resulting in higher cutting efficiency. It is the intention to aim at.

【０００３】[0003]

【発明が解決しようとする問題点】ところで、工具回転
数を増大させると、当然のことながら工具の周速が回転
数に比例して増大する。工具の周速が増大すると一般に
は切削による熱の発生も増大する。また、１刃当たりの
送り量を減少させることにより、切刃近傍のごく狭い範
囲の耐熱性・靱性が要求されるようになる。このこと
は、強度もさることながら、熱的な影響がより大きな因
子となることを示す。以上説明したような高速高送り
は、主に調質材でなく焼き入れ材の切削に効果があるた
め、工具も高硬度のものが望ましい。ところが従来の被
覆超硬合金では今述べたような高速高送りに対応するこ
とが困難であった。However, when the rotational speed of the tool is increased, the peripheral speed of the tool naturally increases in proportion to the rotational speed. As the peripheral speed of the tool increases, the heat generated by cutting generally increases. Further, by reducing the feed amount per blade, heat resistance and toughness in a very narrow range near the cutting edge are required. This indicates that thermal effects, as well as strength, are a greater factor. Since the high-speed high-feed as described above is effective mainly for cutting a hardened material instead of a tempered material, it is preferable that the tool has a high hardness. However, it was difficult for the conventional coated cemented carbide to cope with the high speed and high feed as described above.

【０００４】[0004]

【問題点を解決するための手段】上述したように高速高
送りに対応するには耐熱性と靱性と硬さが十分に兼ね備
わっていればそれで十分であるが、当然全ての性質を最
高に持つことは不可能であり、その兼ね合いが問題とな
る。特にこれらの相乗効果である耐塑性変形性はすべて
の因子と兼ね合っている。本発明者らはどのように、ど
の程度に耐熱性を具備し、どの程度に靱性を持たせ、ど
の程度に靱性を持たせ、且つどのようにような高速高送
り用被覆超硬工具を創製するかについて鋭意検討した結
果、高速高送り適応指数ＨＶＦの概念に到達したのであ
る。[Means for Solving the Problems] As described above, it is sufficient if heat resistance, toughness and hardness are sufficiently combined to cope with high speed and high feed. It is impossible to have, and the trade-off is a problem. In particular, the plastic deformation resistance, which is a synergistic effect of these, balances with all the factors. The present inventors have created how, how much heat resistance, how much toughness, how much toughness, and what kind of coated high-speed, high-feed coated carbide tool. As a result of intensive studies on whether to do so, the concept of the high-speed high-feed adaptation index HVF has been reached.

【０００５】本願発明は、主としてＷＣとＦｅ族金属か
らなる超硬合金に少なくとも一層の皮膜の硬さがＨＶ２
０００以上である単層又は多層の硬質皮膜を被覆した高
速高送り用被覆超硬工具において、該工具の高速高送り
適応指数ＨＶＦが２．３以上であることを特徴とする高
速高送り用被覆超硬工具、である。但し、ＨＶＦ＝
｛（ＨＣ−２００）／２００｝×｛（ＨＲＡ−８５）／
８５｝×｛６／（Ｍ＋６）｝×ＣＲで、ＨＶＦは高速高
送り適応指数、ＨＣは超硬合金の保磁力（Ｏｅ）、ＨＲ
Ａは超硬合金の硬さ（ロックウエルＡスケール）、Ｍは
超硬合金のＦｅ族金属量（重量％）、ＣＲは該超硬合金
のクラック抵抗（ｋｇｆ／ｍｍ）を表す。ここにＣＲの
値はビッカース硬度計の圧子を５０ｋｇｆ荷重にて打
ち、その圧痕の四隅に発生するクラックの長さの総計で
荷重を除した値である。The present invention relates to a cemented carbide mainly composed of WC and Fe group metal, wherein at least one of the coatings has a hardness of HV2.
A high-speed, high-feed coated carbide tool coated with a single-layer or multilayer hard coating having a thickness of at least 000, wherein the high-speed, high-feed index HVF of the tool is 2.3 or more. Carbide tools. However, HVF =
｛(HC-200) / 200｝ × ｛(HRA-85) /
85｝ × {6 / (M + 6)} × CR, HVF is high speed high feed adaptation index, HC is coercive force (Oe) of hard metal, HR
A represents the hardness of the cemented carbide (Rockwell A scale), M represents the amount of Fe group metal in the cemented carbide (% by weight), and CR represents the crack resistance (kgf / mm) of the cemented carbide. Here, the value of CR is a value obtained by hitting an indenter of a Vickers hardness meter with a load of 50 kgf and dividing the load by the total length of cracks generated at the four corners of the indentation.

【０００６】尚、Ｆｅ族金属を主としてＣｏとすること
により耐熱性、靱性にすぐれた合金に、主としてＮｉと
することにより、熱サイクルに対しヒートクラックが発
生しにくい合金となり高速切削により好ましい。また、
ＷＣの一部を周期率表の４ａ、５ａ、６ａ族の炭化物、
窒化物、炭窒化物の群から選ばれた１または２以上の物
質で置換することにより耐摩耗性、耐熱性、耐酸化性が
向上するので鋼の切削により好ましい。An alloy excellent in heat resistance and toughness by mainly using Fe group metal as Co and an alloy mainly using Ni to hardly generate a heat crack in a heat cycle are preferable for high speed cutting. Also,
Part of WC is a carbide of group 4a, 5a, 6a of the periodic table,
By replacing with one or more substances selected from the group consisting of nitrides and carbonitrides, wear resistance, heat resistance, and oxidation resistance are improved, so cutting steel is preferable.

【０００７】[0007]

【作用】該超硬合金母材においてＨＣは構成するＷＣ炭
化物の平均粒径を間接的に表すパラメータで、周知の如
く一定組成の下ではＨＣが大きいと粒径が微細である。
切削用材種において通常ＨＣは２００程度であるがその
２００からの逸脱の割合を示す項が（ＨＣ−２００）／
２００で本発明の主旨を実現するには従来よりある程度
微細ＷＣで構成される合金が条件である。微細ＷＣで構
成される合金とすることで１刃当たりの送り量の減少に
対応できる。同様に（ＨＲＡ−８５）／８５は硬さの８
５からの逸脱の割合である。硬さは被加工物が硬くなる
ため、また過酷な条件で工具寿命を維持するためある程
度高いことが必須である。６／（Ｍ＋６）はＦｅ族金属
量の６％を基準にしてそれからの逸脱の割合の逆数であ
る。通常Ｆｅ族金属量は１２％前後であるのでそれを標
準とした。超硬合金の耐熱性はＦｅ族金属量に依存し、
その量が少ないほど耐熱性が得られる。発明者らは種々
検討した結果、逆数でほぼ耐熱性を評価できることを結
論した。ＣＲは、はぼ１００前後でその値が大きいほど
靱性が高い。本発明者らは、種々の工具を創生して、高
速高送りでの加工の適応性を検討した結果、ＨＶＦが
２．３以上の工具に十分の耐熱性と耐摩耗性を有する皮
膜を被覆することで十分に適応することを実証したので
ある。本発明の主旨に叶うには皮膜も母材同様重要な役
目を担う。特に膜の硬さは耐熱性と耐摩耗性に影響を与
え、高速高送り切削においては少なくともビッカース硬
さ（ＨＶ）が２０００以上の層が存在することが必須で
ある。ＨＶ２０００以上の層が存在しないと急激に膜が
損耗し良好な工具特性が得られない。In the cemented carbide base material, HC is a parameter that indirectly represents the average particle size of the WC carbides constituting it. As is well known, under a certain composition, the larger the HC, the finer the particle size.
In cutting grades, HC is generally about 200, but the term indicating the ratio of deviation from 200 is (HC-200) /
In order to realize the gist of the present invention at 200, an alloy constituted by fine WC to some extent is required. By using an alloy composed of fine WC, it is possible to cope with a decrease in the feed amount per blade. Similarly, (HRA-85) / 85 is a hardness of 8
Percentage deviation from 5. The hardness must be high to some extent in order to harden the workpiece and to maintain the tool life under severe conditions. 6 / (M + 6) is the reciprocal of the rate of deviation from 6% of the amount of Fe group metal. Usually, the amount of the Fe group metal is around 12%, so that was used as a standard. The heat resistance of cemented carbide depends on the amount of Fe group metal,
The smaller the amount, the higher the heat resistance. As a result of various studies, the inventors have concluded that the heat resistance can be almost evaluated by the reciprocal. CR has a toughness higher as its value is larger at around 100. The present inventors have created various tools and studied the applicability of machining at high speed and high feed rate. As a result, a film having sufficient heat resistance and wear resistance has been applied to tools having an HVF of 2.3 or more. It proved that the coating was sufficient for adaptation. In order to achieve the gist of the present invention, the film plays an important role as well as the base material. In particular, the hardness of the film affects heat resistance and abrasion resistance. In high-speed high-feed cutting, it is essential that at least a layer having a Vickers hardness (HV) of 2000 or more is present. If a layer having an HV of 2,000 or more does not exist, the film is rapidly worn and good tool characteristics cannot be obtained.

【０００８】[0008]

【実施例】実施例１を以下のように行った。通常の粉末
冶金法により丸棒素材を製造した。表１に各丸棒試作材
の組成と物理特性ならびにＨＶＦ値を示す。EXAMPLE Example 1 was carried out as follows. A round bar material was manufactured by a usual powder metallurgy method. Table 1 shows the composition, physical properties, and HVF value of each round bar trial material.

【０００９】[0009]

【表１】 [Table 1]

【００１０】この丸棒素材を研削加工して直径８ｍｍの
ボールエンドミル形状に仕上げ、さらに各種の被覆処理
を行ない被覆ボールエンドミル工具とした。まず、表１
の皮膜欄にａと表示したものは、ＴｉＣＮ膜単層で膜の
硬さは２８００、ｂと表示したものは、ＴｉＡｌＮ膜単
層で、硬さは２７００であり、ｃと表示したものは、母
材側がＴｉＮで、その硬さは２２００、表面側がＴｉＡ
ｌＮであり、ｄと表示したものは、母材側がＴｉＮ、中
間にＴｉＡｌＮ、表面側にＴｉＮの３層を被覆した。[0010] The round bar material was ground into a ball end mill shape having a diameter of 8 mm, and further subjected to various coating treatments to obtain a coated ball end mill tool. First, Table 1
In the coating column of “a”, the hardness of the film was 2800 in the single layer of TiCN film, and the hardness of the film was 2700 in the case of “b”, and the hardness was 2700 in the single layer of the TiAlN film. The base material side is TiN, its hardness is 2200, and the surface side is TiA
In the case of 1N and d, three layers of TiN were coated on the base material side, TiAlN in the middle, and TiN on the surface side.

【００１１】これら被覆ボールエンドミル工具を用いて
高速高送りでの切削テストを実施した。切削加工条件
は、回転数３０、０００ｒｐｍ、テーブル送り１０ｍ／
分、切り込み量は、ピックフィード０．８ｍｍとし、被
削材は焼き入れ鋼（ＨＲＣ５０）を用いた。その結果も
表１に併記した。表１より、本発明例は、ＨＶＦ値と切
削長がほぼ相関し、高い硬さの例ほど長時間の切削がで
きたのにたいし、従来例は、ほぼ１／２〜１／４程度で
切削不能となったが、切削不能の状態を観察すると、刃
先が塑性変形を生じ切削できない状態となり寿命となっ
ていた。Using these coated ball end mill tools, cutting tests were performed at high speed and high feed. The cutting conditions were as follows: rotation speed 30,000 rpm, table feed 10 m /
The amount of cut and the amount of cut were 0.8 mm in pick feed, and the work material was hardened steel (HRC50). The results are also shown in Table 1. From Table 1, it can be seen that in the present invention example, the HVF value and the cutting length were almost correlated, and the example of higher hardness was able to cut for a longer time, whereas the conventional example was about 1/2 to 1/4. However, when observing the non-cuttable state, the cutting edge was plastically deformed and could not be cut.

【００１２】実施例２として以下を行った。通常の粉末
冶金法により丸棒素材を製造した。表２に各丸棒試作材
の組成と物理特性ならびにＨＶＦ値を示す。The following was performed as Example 2. A round bar material was manufactured by a usual powder metallurgy method. Table 2 shows the composition, physical properties, and HVF value of each round bar trial material.

【００１３】[0013]

【表２】 [Table 2]

【００１４】この丸棒素材を実施例１と同様に研削加工
して直径８ｍｍのボールエンドミル形状に仕上げ、さら
に各種の被覆処理を行ない被覆ボールエンドミル工具と
した。表２の皮膜欄は実施例１と同様である。これら被
覆ボールエンドミル工具を用いて高速高送りでの切削テ
ストを実施した。切削加工条件は、回転数４０、０００
ｒｐｍ、テーブル送り１６ｍ／分、切り込み量は、ピッ
クフィード０．８ｍｍとし、被削材は焼き入れ鋼（ＨＲ
Ｃ６１）を用いた。その結果も表２に併記した。表１、
２より、本発明例は、切削可能長から判断されるように
本発明品は極めて優れた切削特性を示す。This round bar material was ground in the same manner as in Example 1 to form a ball end mill having a diameter of 8 mm, and was subjected to various coating treatments to obtain a coated ball end mill tool. The coating column in Table 2 is the same as in Example 1. Using these coated ball end mill tools, cutting tests were performed at high speed and high feed. The cutting conditions were 40,000 revolutions.
rpm, table feed 16 m / min, depth of cut is 0.8 mm pick feed, and the work material is hardened steel (HR
C61) was used. The results are also shown in Table 2. Table 1,
From 2, it can be seen that the product of the present invention shows extremely excellent cutting characteristics as judged from the possible cutting length.

【００１５】[0015]

【００１６】[0016]

【発明の効果】このように高速高送り適応指数に着目し
て創生した本発明例は、耐熱性に優れ、かつ、切削時の
耐塑性変形性に優れるため長時間安定した切削ができた
のに対し、Ｃｏ含有量の高い従来例や、ＷＣ粒径の比較
的大きな例は、時間の経過とともに突然切削不能となり
折損し、寿命となった。また、切削時の刃先温度が高い
ためＡｌを含有したＴｉＡｌＮ皮膜を用いた例の切削時
間が長くなる傾向にあるが、用途としてＴｉＣＮ皮膜、
ＴｉＮ皮膜でも基体そのものが耐塑性変形性に優れるた
め、安定した切削が可能である。As described above, the present invention, which was created by focusing on the high-speed high-feed adaptation index, was excellent in heat resistance and plastic deformation resistance during cutting, so that stable cutting could be performed for a long time. On the other hand, in the conventional example having a high Co content and in the example having a relatively large WC particle size, cutting became impossible suddenly with the passage of time, causing breakage, and the life was extended. In addition, since the cutting edge temperature at the time of cutting is high, the cutting time of an example using a TiAlN film containing Al tends to be long.
Even with the TiN coating, stable cutting is possible because the substrate itself has excellent plastic deformation resistance.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 主としてＷＣとＦｅ族金属からなる超硬
合金に少なくとも一層の皮膜の硬さがＨＶ２０００以上
である単層又は多層の硬質皮膜を被覆した高速高送り用
被覆超硬工具において、該工具の高速高送り適応指数Ｈ
ＶＦが２．３以上であることを特徴とする高速高送り用
被覆超硬工具。但し、ＨＶＦ＝｛（ＨＣ−２００）／２
００｝×｛（ＨＲＡ−８５）／８５｝×｛６／（Ｍ＋
６）｝×ＣＲで、ＨＶＦは高速高送り適応指数、ＨＣは
超硬合金の保磁力（Ｏｅ）、ＨＲＡは超硬合金の硬さ
（ロックウエルＡスケール）、Ｍは超硬合金のＦｅ族金
属量（重量％）、ＣＲは該超硬合金のクラック抵抗（ｋ
ｇｆ／ｍｍ）を示す。1. A high-speed, high-feed coated cemented carbide tool in which a cemented carbide mainly composed of WC and a Fe group metal is coated with a single-layer or multilayer hard film having a hardness of at least one layer of HV2000 or more. High-speed, high-feed tool index H
A coated carbide tool for high-speed and high-feed, wherein VF is 2.3 or more. However, HVF = ｛(HC-200) / 2
00｝ × ｛(HRA-85) / 85｝ × ｛6 / (M +
6)｝ × CR, HVF is high speed high feed adaptation index, HC is coercive force (Oe) of cemented carbide, HRA is hardness of cemented carbide (Rockwell A scale), M is Fe group metal of cemented carbide Amount (% by weight), CR is the crack resistance (k
gf / mm).