JP3544632B2 - Coated cemented carbide - Google Patents
Coated cemented carbide Download PDFInfo
- Publication number
- JP3544632B2 JP3544632B2 JP14699899A JP14699899A JP3544632B2 JP 3544632 B2 JP3544632 B2 JP 3544632B2 JP 14699899 A JP14699899 A JP 14699899A JP 14699899 A JP14699899 A JP 14699899A JP 3544632 B2 JP3544632 B2 JP 3544632B2
- Authority
- JP
- Japan
- Prior art keywords
- cemented carbide
- compound
- cutting
- base material
- particle size
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【０００１】
【発明の属する技術分野】
本発明は、例えば、切削工具等に使用される高い耐摩耗性と高い耐欠損性を兼ね備えた被覆超硬合金に関するものである。
【０００２】
【従来の技術】
近年、金属部材の切削加工において高能率加工への要求が強く、切削速度が高速化している中で、超硬合金母材表面にＴｉＣなどの硬質被覆層を蒸着した被覆超硬合金が切削工具の材質として多用されている。更に、環境への配慮から刃先冷却用の切削油を用いない乾式切削が好まれる傾向があり、これら被覆超硬合金製の切削工具に対して乾式切削などの高温切削（刃先が高温となる）における耐久性が求められている。
【０００３】
このような要求に対して、旧来のＷＣのみを硬質相として含む超硬合金を母材とした切削工具では、乾式切削などの高温切削（刃先が高温となる）における耐久性不足という点で十分に要求に応えることができなかった。
【０００４】
そのため超硬合金母材中にＴｉＣなど４ａ，５ａ，６ａ族金属化合物を添加し、高温切削における耐久性を向上せしめる試みがなされている。このうちＴｉＣやＴａＣ等のＴｉやＴａの化合物のみを添加したものは硬度が向上したが、靭性が不充分あるという問題があり、他方Ｚｒ，Ｈｆの炭化物や窒化物のみを添加したものは、靭性の低下が少なく、高温下での靭性が高いという特徴を持つが、硬度が低いため耐摩耗性に難があり、前記要求に十分応えるものではなかった。
【０００５】
これら超硬合金母材の欠点を解消するため、Ｚｒ及び／またはＨｆの化合物とＴｉ化合物の両方を添加することが提案されている（特開平６−９３４７３号）。この超硬合金は、Ｚｒ及び／またはＨｆの化合物で合金靱性の維持を図り、かつ合金硬度を不足するためＴｉ化合物を添加し、共存させたものである。また、この超硬合金は、合金中にＺｒ及び／またはＨｆの炭化物などを添加すると、Ｔｉの炭化物などはＷＣと固溶しにくくなる特性を利用しており、該特性によりＷＣ減少量が非常に少なく靭性の低下を解消できるので、Ｚｒ，Ｈｆの炭化物や窒化物の高靭性を十分に利用できることを特徴とする。
【０００６】
更に、上記超硬合金は、合金の表面から２〜１００μｍ 以内の深さにわたって、Ｚｒ及び／またはＨｆの化合物の硬質相とＴｉ化合物の硬質相が減少又は消失してなる表層領域を有しており、この表層領域を有することで合金表層領域の靭性を向上させている。
【０００７】
また最近、このような超硬合金においてＺｒ及び／またはＨｆの化合物の平均粒径を１μｍ以上１０μｍ以下に制御することにより靭性、耐塑性変形性、耐摩耗性を向上せしめることが提案されている（特開平１０−１８０３８号）。
【０００８】
【発明が解決しようとする課題】
前記Ｚｒ及び／またはＨｆの化合物とＴｉ化合物の両方を添加した超硬合金により作製した切削工具は耐熱性に優れるため長時間の高速切削に耐える。しかしながら、ニアネットシェイプの技術の進歩により、部品素材の形状は益々複雑なものとなってきており、その切削加工には断続切削が多く含まれるようになってきている。また、連続切削においても、高能率加工への要求が益々強くなったことにより、切削条件を上げ、刃先温度が非常に高温となる切削加工が多く含まれるようになってきている。従って、切削工具にかかる衝撃力、衝撃回数、刃先温度は増加、上昇の一途を辿っており、このような厳しい条件での加工に対して、特に乾式切削には、超硬合金の母材にＺｒ及び／またはＨｆの化合物とＴｉ化合物の両方を添加するだけでは対応できないようになってきている。
【０００９】
即ち、前述のように上記超硬合金は、Ｚｒ及び／またはＨｆの化合物の硬質相とＴｉ化合物の硬質相が減少又は消失してなる表層領域を有しているが、この領域は、非常に高い温度となると塑性変形を起こしやすく、異常摩耗や欠損により切削加工の省力化、無人化の大きな障害となっている。
【００１０】
また、このような超硬合金においてＺｒ及び／またはＨｆの化合物の平均粒径を１μｍ以上１０μｍ以下に制御することについても、上記非常に高い温度での塑性変形の問題を完全に解決するものでなく、靱性の向上の効果も見られなかった。
【００１１】
そこで本発明は、このような従来技術の課題に鑑み、長時間の高速切削に耐え、且つ、厳しい条件での乾式切削にも安定的に適用することができる切削工具に最適な、被覆超硬合金を提供することを課題とする。
【００１２】
【課題を解決するための手段】
前記課題を解決するため、本発明の被覆超硬合金は、ＷＣと鉄族金属からなる結合相金属と硬質相とからなる超硬合金母材の表面に被覆層を被着させた被覆超硬合金において、前記硬質相はＺｒ及び／又はＨｆの酸化物、炭化物、窒化物、炭窒化物の少なくとも１種を含有する化合物から成り、かつ、該化合物の平均粒径が、超硬合金母材の表面から深さ５０μｍの領域は０．０２〜０．５μｍ、１５０μｍの深さの領域は１．０〜５．０μｍであり、更に前記被覆層は、周期律表４ａ、５ａ、６ａ族金属の酸化物、炭化物、窒化物、ホウ化物及び酸化アルミニウムの少なくとも１種から成る単層又は多重層で構成される。
【００１３】
このような構造をとる理由を以下に説明する。Ｚｒ及び／又はＨｆの酸化物、炭化物、窒化物、炭窒化物の少なくとも１種を含有する化合物（以下、Ｚｒ等の化合物と略称する）は、硬質相として多用される４ａ、５ａ、６ａ族金属を主成分とする化合物の中でも合金強度の維持の効果も最も大きい。Ｚｒ及び／又はＨｆは、その一部が炭化物等の形で合金中に分散し高温での合金強度を高め被覆超硬合金の耐塑性変形性を向上させている。他の一部は結合相中に固溶して結合相の耐塑性変形性を向上させている。さらに、Ｚｒ等の化合物は高温での塑性変形を防ぐ作用がある。しかしながら、これら利点の反面、Ｚｒ等の化合物の存在が超硬合金母材の硬度を低下せしめ、また、耐摩耗性を劣化せしめる傾向があることが知られている。
【００１４】
本発明者は、上記のような被覆超硬合金について硬度低下や摩耗性低下の要因を調査し、鋭意研究を加えた結果、超硬合金母材の表層と内方でＺｒ等の化合物の粒径を大きく違えることにより完成にいたったもので、その特徴は、Ｚｒ等の化合物の平均粒径が、超硬合金母材の表面から深さ５０μｍの領域は０．０２〜０．５μｍ、１５０μｍの深さの領域は１．０〜５．０μｍである。
【００１５】
前記Ｚｒ等の化合物の粒径について、超硬合金母材の表面から深さ５０μｍの領域の平均粒径を０．０２〜０．５μｍと微粒化するのは、微粒化により、超硬合金母材表面近傍領域での靱性を高め、耐チッピング性を向上せしめるためである。この平均粒径が０．０２μｍ未満の場合、連続切削における耐摩耗性が劣化するとともに、断続切削でも欠損し易くなり、０．５μｍより大きい場合、靱性が劣化して欠損し易くなる。他方、Ｚｒ等の化合物の粒径を、超硬合金母材の表面から深さ１５０μｍ以上の領域の平均粒径を１．０〜５．０μｍと粗粒化するのは、粗粒化により耐塑性変形性が向上し、その結果、超硬合金母材表面の耐摩耗性を維持することができるためである。この平均粒径が１．０μｍ未満の場合、連続切削における耐摩耗性が劣化するとともに、断続切削でも欠損し易くなり、５．０μｍより大きい場合、靱性が劣化して欠損し易くなる。
【００１６】
尚、粒径の測定は超硬合金母材を深さ方向に１ｍｍ研削し、ダイヤモンドペーストによって研磨し鏡面状態とした後、金属顕微鏡にて写真撮影後、インタセプト法により粒径を求めた。
【００１７】
またＺｒ等の化合物の粒径が、超硬合金母材の表面から深さ５０μｍ〜１５０μｍの領域で０．５μｍ〜１．０μｍとし、超硬合金の表面から内部に向かって、傾斜的に大きくなるようにすると、靱性が向上し、欠損しにくくなる。なお、本発明では、上記平均粒径の傾斜の有無に拘らず、本発明では、Ｚｒ等の化合物よりなる硬質相やその他の周期律表４ａ、５ａ、６ａ族金属の炭化物、窒化物、炭窒化物から硬質相が消出している領域は設けない。
【００１８】
前記Ｚｒおよび／またはＨｆには、予めＷ，Ｔａ，Ｎｂ，Ｖ等を固溶させた炭化物、炭窒化物などの形で合金中に添加することができる。また、Ｚｒ等の化合物は、ＺｒとＨｆとが固溶したものであっても本発明の効果を妨げない。また前記Ｚｒ等の化合物について、超硬合金母材が炭化物化合物および非炭化物化合物の両方を兼備することにより、ＦＣＤ４５０などの材料を加工する場合に特に顕著な性能となる非常に有効であることも見いだした。
【００１９】
ところで、本発明はＴｉの炭化物、窒化物、炭窒化物を硬質層として含む可能性を妨げるものではないが、このようなＴｉ化合物を添加した場合に、表層からＺｒ等の化合物が消出してしまう場合があるので注意が必要である。むしろ本発明は、Ｔｉ化合物の添加を必ずしも必要としないことも一つの特徴である。例えば、出発原料をＺｒＣ（及び／またはＨｆ），Ｃｏ，ＷＣのみとして超硬合金母材を形成しても、長時間の高温、高速切削に耐え、且つ、厳しい条件でのドライ切削にも安定的に適用することができるような、耐摩耗性および耐欠損性を兼ね備えたものとなる。
【００２０】
また、本発明は超硬合金母材に、必ずしも窒素を含有させる必要がない。窒化物は、炭化物に比べ熱伝導率が高いなどの熱的特性に優れるが、本発明は窒素を含有しなくても厳しい加工条件での優れた耐摩耗性および耐欠損性を兼ね備えたものとなる。
【００２１】
このような超硬合金母材の構造が形成される理由は不明だが、前記Ｚｒ等の化合物の原料を超硬合金原料に添加し、これらの原料成形体を窒素以外の不活性ガス雰囲気中、液相出現温度（約１２５０〜１３００℃）以上で焼結することにより得られる。この製法では、炉内圧力を高くすることで表面部と内部の拡散が起こり、その結果Ｚｒ等の化合物の組織が変化し、粒径が表層と内部コアで大きく異なるのではないかと推測される。なお、粒径の制御は、昇温過程、焼結過程の雰囲気圧力を制御することで行う。
【００２２】
そして、以上に示した超硬合金母材の表面に被覆層が形成される。被覆層は、周期律表４ａ、５ａ、６ａ族金属の酸化物、炭化物、窒化物、ホウ化物及び酸化アルミニウムの少なくとも１種から成る単層又は多重層であり、通常のＣＶＤ、ＰＶＤ法により形成する。このように被覆層を形成することで、合金の耐摩耗性を確保できる。
【００２３】
【実施例】
以下、本発明の具体的な実施形態およびその作用を実施例により詳細に説明する。
【００２４】
（実施例１ ）
原料粉末として、Ｗ，Ｚｒ，Ｈｆの金属、炭化物、Ｃｏ金属の粉末を準備し、焼結体組成が表１に示す組成となるように秤量し、この粉体を超硬合金製のボールミルで１８時間混合粉砕した。
【００２５】
【表１】
次に混合した粉体を圧力２ｔｏｎ／ｃｍ２ で加圧成形し、この成形体を液相出現温度（１２５０〜１３００℃）以上で、アルゴン雰囲気にて焼成する。雰囲気圧は０．８Ｔｏｒｒとした。
【００２７】
このとき焼成条件によっては、表面部にＺｒ等の化合物からなる相の存在しない層ができることがある。このときは、ブラスト処理や研磨などの機械的加工により表面部を除去することで、表面までＺｒ等の化合物相が存在する合金焼結体とすることができる。
【００２８】
得られた合金焼結体につき、超硬合金母材を深さ方向に１ｍｍ研削し、ダイヤモンドペーストによって研磨し鏡面状態とした後、金属顕微鏡にて写真撮影後、インタセプト法により平均粒径を算出した。なお、平均粒径は超硬合金母材の表面から深さ５０μｍの領域（表層）と、深さ５０μｍ〜１５０μｍの領域（中間層）と、深さ１５０μｍ以上の領域（内部コア）について求めた。これらを表１に記載する。
【００２９】
また、表面から深さ５０μｍ〜１５０μｍの領域でＺｒ等の化合物の平均粒径が０．５μｍ〜１．０μｍとなっているものを、表１中、粒径が傾斜的になっているものとして粒度分布［有］として示し、そうでないものを粒度分布［無］として示す。
【００３０】
さらに、通法に従い、硬質相の成分を特定し、ＺｒＣ相の有無を確認した。その結果を表１に記載する。
【００３１】
なお、焼結体Ｎｏ．１〜４、８、９は硬質相がＺｒＯとＷＣのみからなり、Ｎｏ．５は、これらに加えてＺｒＣを、そしてＮｏ．６、７はさらにＨｆＣを含んでいた。
【００３２】
これら焼結体を母材として通常のＣＶＤ法にて、内層に１μｍのＴｉＮ、５μｍのＴｉＣＮ、外層に３μｍのＡｌ２ Ｏ３ 、最外層に０．５μｍのＴｉＮを被覆し、下記に示す条件で、乾式切削の連続切削試験と断続切削試験を行ない、摩耗幅の測定と、欠損の有無を確認した。
【００３３】
これらの結果を表２に示す。
【００３４】
［試験条件］
（連続切削試験１）
被削材 ：ＦＣ２５０、円筒材
切削速度：４５０ｍ／ｍｉｎ
切込み ：２．０ｍｍ
送り ：０．５ｍｍ／ｒｅｖ
切削油 ：なし
切削時間：３０ｍｉｎ
（連続切削試験２）
被削材 ：ＦＣＤ４５０、円筒材
切削速度：３００ｍ／ｍｉｎ
切込み ：２．０ｍｍ
送り ：０．５ｍｍ／ｒｅｖ
切削油 ：なし
切削時間：１５ｍｉｎ
（断続切削試験）
被削材 ：ＦＣＤ４５０、５ｍｍ幅溝４本入り円筒材
切削速度：１００ｍ／ｍｉｎ
切込み ：２．０ｍｍ
送り ：０．５ｍｍ／ｒｅｖ
切削油 ：なし
切削時間：１０ｍｉｎ
【００３５】
【表２】
表２から明らかなように、前記粒度分布が有る試料Ｎｏ．２〜７はいずれも、連続切削試験の摩耗幅が０．３０ｍｍ未満と小さく、また、断続切削試験で欠損も起こらなかったことから、良好な耐摩耗性と耐欠損性を示していた。
【００３７】
この中でもＺｒＣ相を含む試料Ｎｏ．５〜７はＦＣＤ４５０を被削材とする連続切削試験２で摩耗幅が０．２０ｍｍ未満という優れた耐摩耗性を示した。
【００３８】
また、前記粒度分布がない試料Ｎｏ．１は、断続切削試験で欠損する場合もあったが、連続切削試験の摩耗幅が０．３０ｍｍ未満と小さく優れた耐摩耗性を示した。
【００３９】
これに対して、試料Ｎｏ．８、９は本発明の範囲外にある。すなわち、試料Ｎｏ．８は前記粒度分布がなく、かつ、超硬合金母材の表面から厚さ５０μｍの表層でのＺｒ化合物の平均粒径が０．０２μｍ未満であり、連続切削試験の摩耗幅が０．５０ｍｍもあり、また、断続切削試験で切削し易かった。また、試料Ｎｏ．９は前記粒度分布がなく、かつ、超硬合金母材の表面から１５０μｍよりも内方の内部コアでのＺｒ化合物の平均粒径が１０．０μｍと大きく、その結果、連続切削試験の摩耗幅は小さかったが、断続切削試験では、９割が欠損してしまった。
【００４０】
【発明の効果】
叙上のように本発明の被覆超硬合金によれば、超硬合金母材の表面に被覆層を被着させた被覆超硬合金において、前記硬質相はＺｒ及び／又はＨｆの酸化物、炭化物、窒化物、炭窒化物の少なくとも１種を含有する化合物から成り、かつ、該化合物の平均粒径が、超硬合金母材の表面から深さ５０μｍの領域は０．０２〜０．５μｍ、１５０μｍの深さの領域は１．０〜５．０μｍとしたことにより、切削工具として使用した場合に、高温での靱性、硬度、耐塑性変形性が飛躍的に向上し、長時間の高温、高速切削に耐えるものである。また、従来では、ほとんど不可能であった厳しい条件での乾式切削にも安定的に適用することができる。
【００４１】
このように本発明の被覆超硬合金によれば、金属部材の切削加工における高能率加工への要求と、刃先冷却用の切削油を用いない環境への配慮という要求に対し十二分に応えるものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coated cemented carbide having both high wear resistance and high fracture resistance used for, for example, cutting tools.
[0002]
[Prior art]
In recent years, there has been a strong demand for high-efficiency machining in the cutting of metal members, and as cutting speeds have increased, coated cemented carbide in which a hard coating layer such as TiC has been deposited on the surface of a cemented carbide base material has become a cutting tool. It is often used as a material for Furthermore, there is a tendency that dry cutting without using cutting oil for cutting edge cooling is preferred from the viewpoint of environmental considerations, and high-temperature cutting such as dry cutting for these coated cemented carbide cutting tools (the cutting edge becomes hot). Durability is required.
[0003]
In response to such a demand, a conventional cutting tool using a cemented carbide containing only WC as a hard phase as a base material is sufficient in terms of insufficient durability in high-temperature cutting such as dry cutting (the cutting edge becomes high temperature). Could not meet the demand.
[0004]
For this reason, attempts have been made to add group 4a, 5a, 6a metal compounds such as TiC to the cemented carbide base material to improve durability in high-temperature cutting. Among them, those to which only compounds of Ti and Ta such as TiC and TaC are added have improved hardness, but have a problem of insufficient toughness. On the other hand, those to which only carbides and nitrides of Zr and Hf are added, It is characterized by a small decrease in toughness and a high toughness at high temperatures, but has a low hardness, so that it has difficulty in abrasion resistance and cannot meet the above requirements sufficiently.
[0005]
It has been proposed to add both a Zr and / or Hf compound and a Ti compound in order to solve these disadvantages of the cemented carbide base material (Japanese Patent Application Laid-Open No. Hei 6-93473). This cemented carbide is made of a compound of Zr and / or Hf to maintain the alloy toughness and to coexist with the addition of a Ti compound due to insufficient alloy hardness. Further, this cemented carbide utilizes the property that, when a carbide of Zr and / or Hf is added to the alloy, the carbide of Ti and the like hardly form a solid solution with WC. Since the reduction in toughness can be eliminated, the high toughness of carbides and nitrides of Zr and Hf can be sufficiently utilized.
[0006]
Furthermore, the cemented carbide has a surface layer region in which the hard phase of the compound of Zr and / or Hf and the hard phase of the Ti compound decrease or disappear over a depth of 2 to 100 μm from the surface of the alloy. The presence of this surface region improves the toughness of the alloy surface region.
[0007]
Recently, it has been proposed to improve the toughness, plastic deformation resistance and wear resistance by controlling the average particle size of the compound of Zr and / or Hf in such a cemented carbide to 1 μm or more and 10 μm or less. (JP-A-10-18038).
[0008]
[Problems to be solved by the invention]
A cutting tool made of a cemented carbide to which both a compound of Zr and / or Hf and a Ti compound are added has excellent heat resistance and can withstand high-speed cutting for a long time. However, due to the progress of the near net shape technology, the shape of the component material has become more and more complicated, and the cutting process has often included intermittent cutting. Also, in continuous cutting, as the demand for high-efficiency machining has increased, cutting conditions have been increased, and many cutting processes in which the edge temperature is extremely high have been included. Therefore, the impact force applied to the cutting tool, the number of impacts, and the cutting edge temperature are constantly increasing and rising. For machining under such severe conditions, especially in dry cutting, the base material of cemented carbide is used. It has become impossible to cope only by adding both a compound of Zr and / or Hf and a Ti compound.
[0009]
That is, as described above, the cemented carbide has a surface layer region in which the hard phase of the compound of Zr and / or Hf and the hard phase of the Ti compound decrease or disappear. At high temperatures, plastic deformation is apt to occur, and abnormal wear or loss is a major obstacle to labor saving and unmanned cutting.
[0010]
Controlling the average particle size of the compound of Zr and / or Hf in such a cemented carbide to 1 μm or more and 10 μm or less also completely solves the problem of plastic deformation at a very high temperature. No effect of improving toughness was observed.
[0011]
Accordingly, the present invention has been made in view of the problems of the prior art described above, and is suitable for a cutting tool that can withstand high-speed cutting for a long time and can be stably applied to dry cutting under severe conditions. It is an object to provide an alloy.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a coated cemented carbide according to the present invention is a coated cemented carbide in which a coating layer is applied to the surface of a cemented carbide base material composed of a binder phase metal composed of WC and an iron group metal and a hard phase. In the alloy, the hard phase is made of a compound containing at least one of oxides, carbides, nitrides, and carbonitrides of Zr and / or Hf, and the compound has an average particle size of a cemented carbide base material. The region having a depth of 50 μm from the surface is 0.02 to 0.5 μm, the region having a depth of 150 μm is 1.0 to 5.0 μm, and the coating layer is formed of a metal belonging to Group 4a, 5a or 6a of the periodic table. Of oxides, carbides, nitrides, borides and aluminum oxides.
[0013]
The reason for adopting such a structure will be described below. Compounds containing at least one of oxides, carbides, nitrides, and carbonitrides of Zr and / or Hf (hereinafter, abbreviated as compounds such as Zr) are group 4a, 5a, and 6a which are frequently used as hard phases. Among compounds containing metal as a main component, the effect of maintaining alloy strength is the largest. Part of Zr and / or Hf is dispersed in the alloy in the form of carbide or the like, thereby increasing the alloy strength at high temperatures and improving the plastic deformation resistance of the coated cemented carbide. Another part is dissolved in the binder phase to improve the plastic deformation resistance of the binder phase. Further, compounds such as Zr have an effect of preventing plastic deformation at high temperatures. However, on the other hand, it is known that the presence of a compound such as Zr tends to lower the hardness of the cemented carbide base material and deteriorate the wear resistance.
[0014]
The present inventor has investigated the causes of the decrease in hardness and abrasion of the coated cemented carbide as described above, and as a result of diligent research, found that particles of a compound such as Zr in the surface layer and inward of the cemented carbide base material. It was completed by a large difference in diameter, and the feature is that the average particle size of the compound such as Zr is 0.02-0.5 μm, 150 μm in the region of 50 μm depth from the surface of the cemented carbide base material. Is 1.0 to 5.0 μm.
[0015]
With respect to the particle diameter of the compound such as Zr, the average particle diameter in the region of 50 μm deep from the surface of the cemented carbide base material is reduced to 0.02 to 0.5 μm. This is because the toughness in the region near the material surface is increased and the chipping resistance is improved. When the average particle size is less than 0.02 μm, wear resistance in continuous cutting is deteriorated, and chipping is apt to occur in intermittent cutting. When it is larger than 0.5 μm, toughness is deteriorated and chipping is liable. On the other hand, the reason why the particle size of the compound such as Zr is coarsened to an average particle size of 1.0 to 5.0 μm in a region having a depth of 150 μm or more from the surface of the cemented carbide base material is that the resistance to the coarseness This is because the plastic deformability is improved, and as a result, the wear resistance of the surface of the cemented carbide base material can be maintained. When the average particle size is less than 1.0 μm, the wear resistance in continuous cutting is deteriorated, and the chip is easily broken even in intermittent cutting. When the average particle size is more than 5.0 μm, the toughness is deteriorated and the chip is easily broken.
[0016]
The particle size was measured by grinding the cemented carbide base material by 1 mm in the depth direction, polishing with a diamond paste to a mirror surface, taking a photograph with a metallographic microscope, and determining the particle size by an intercept method.
[0017]
The particle size of the compound such as Zr is set to 0.5 μm to 1.0 μm in a region having a depth of 50 μm to 150 μm from the surface of the cemented carbide base material, and gradually increases from the surface of the cemented carbide toward the inside. In such a case, the toughness is improved, and the fracture is less likely to occur. In the present invention, irrespective of the presence or absence of the gradient of the average particle diameter, in the present invention, a hard phase made of a compound such as Zr or other carbides, nitrides, and carbons of metals in the periodic table 4a, 5a, and 6a are used. There is no region where the hard phase disappears from the nitride.
[0018]
Zr and / or Hf can be added to the alloy in the form of carbide, carbonitride, or the like in which W, Ta, Nb, V, or the like is previously dissolved. In addition, even if the compound such as Zr is a solid solution of Zr and Hf, the effect of the present invention is not hindered. Also, regarding the compound such as Zr, the cemented carbide base material has both carbide compound and non-carbide compound, so that it is very effective when processing a material such as FCD450 becomes particularly remarkable. I found it.
[0019]
By the way, the present invention does not prevent the possibility of including a carbide, nitride, and carbonitride of Ti as a hard layer. However, when such a Ti compound is added, compounds such as Zr disappear from the surface layer. It is necessary to be careful as it may happen. Rather, one feature of the present invention is that addition of a Ti compound is not necessarily required. For example, even if a cemented carbide base material is formed using only ZrC (and / or Hf), Co, and WC as a starting material, it can withstand high-temperature and high-speed cutting for a long time and is stable even in dry cutting under severe conditions. It has both abrasion resistance and fracture resistance so that it can be applied in a specific manner.
[0020]
In the present invention, it is not always necessary to include nitrogen in the cemented carbide base material. Nitride is superior in thermal properties such as high thermal conductivity compared to carbide, but the present invention is said to have excellent wear resistance and fracture resistance under severe processing conditions without containing nitrogen. Become.
[0021]
The reason why the structure of such a cemented carbide base material is formed is unknown, but the material of the compound such as Zr is added to the material of the cemented carbide, and these material compacts are placed in an inert gas atmosphere other than nitrogen. It is obtained by sintering at or above the liquid phase appearance temperature (about 1250 to 1300 ° C.). In this manufacturing method, diffusion of the surface portion and the inside occurs by increasing the pressure in the furnace, and as a result, the structure of the compound such as Zr changes, and it is speculated that the particle size may differ greatly between the surface layer and the inner core. . The control of the particle size is performed by controlling the atmospheric pressure during the temperature raising process and the sintering process.
[0022]
Then, a coating layer is formed on the surface of the cemented carbide base material described above. The coating layer is a single layer or a multi-layer composed of at least one of oxides, carbides, nitrides, borides and aluminum oxides of metals of Groups 4a, 5a and 6a of the periodic table, and is formed by ordinary CVD and PVD methods. I do. By forming the coating layer in this manner, the wear resistance of the alloy can be ensured.
[0023]
【Example】
Hereinafter, specific embodiments of the present invention and the operation thereof will be described in detail with reference to examples.
[0024]
(Example 1)
Powders of W, Zr, and Hf metals, carbides, and Co metals are prepared as raw material powders, weighed so that the composition of the sintered body has the composition shown in Table 1, and then the powder is subjected to ball milling using a cemented carbide alloy. The mixture was pulverized for 18 hours.
[0025]
[Table 1]
Next, the mixed powder is molded under pressure at a pressure of 2 ton / cm 2 , and the molded body is fired in an argon atmosphere at a liquid phase appearance temperature (1250 to 1300 ° C.) or higher. The atmosphere pressure was set to 0.8 Torr.
[0027]
At this time, depending on the sintering conditions, a layer having no phase composed of a compound such as Zr may be formed on the surface. At this time, by removing the surface portion by mechanical processing such as blasting or polishing, an alloy sintered body in which a compound phase such as Zr exists up to the surface can be obtained.
[0028]
For the obtained sintered alloy, the cemented carbide base material was ground by 1 mm in the depth direction, polished with diamond paste to a mirror surface, photographed with a metallographic microscope, and the average particle size was calculated by the intercept method. did. The average particle size was determined for a region (surface layer) having a depth of 50 μm from the surface of the cemented carbide base material, a region having a depth of 50 μm to 150 μm (intermediate layer), and a region having a depth of 150 μm or more (inner core). . These are described in Table 1.
[0029]
Further, in the region having a depth of 50 μm to 150 μm from the surface, those having an average particle diameter of a compound such as Zr of 0.5 μm to 1.0 μm are shown in Table 1 as those having an inclined particle diameter. The particle size distribution is shown as [presence], and the others are shown as particle size distribution [absence].
[0030]
Further, the components of the hard phase were specified according to the conventional method, and the presence or absence of the ZrC phase was confirmed. Table 1 shows the results.
[0031]
The sintered body No. In Nos. 1 to 4, 8, and 9, the hard phases consisted only of ZrO and WC. No. 5 additionally contains ZrC, and No. 5 6, 7 further contained HfC.
[0032]
Using these sintered bodies as a base material, the inner layer is coated with 1 μm TiN, 5 μm TiCN, the outer layer with 3 μm Al 2 O 3 , and the outermost layer with 0.5 μm TiN by the ordinary CVD method. Then, a continuous cutting test and an intermittent cutting test of dry cutting were performed, and the wear width was measured and the presence or absence of defects was confirmed.
[0033]
Table 2 shows the results.
[0034]
[Test condition]
(Continuous cutting test 1)
Work material: FC250, cylindrical material Cutting speed: 450 m / min
Cut: 2.0mm
Feed: 0.5mm / rev
Cutting oil: None Cutting time: 30 min
(Continuous cutting test 2)
Work material: FCD450, cylindrical material cutting speed: 300 m / min
Cut: 2.0mm
Feed: 0.5mm / rev
Cutting oil: None Cutting time: 15 min
(Intermittent cutting test)
Work material: FCD450, Cylindrical material with four 5mm width grooves Cutting speed: 100m / min
Cut: 2.0mm
Feed: 0.5mm / rev
Cutting oil: None Cutting time: 10 min
[0035]
[Table 2]
As is clear from Table 2, Sample No. having the particle size distribution described above. In each of Nos. 2 to 7, the wear width in the continuous cutting test was as small as less than 0.30 mm, and no breakage occurred in the intermittent cutting test, indicating good wear resistance and chipping resistance.
[0037]
Among them, sample No. 1 containing the ZrC phase was used. Nos. 5 to 7 showed excellent wear resistance with a wear width of less than 0.20 mm in a continuous cutting test 2 using FCD450 as a work material.
[0038]
Sample No. having no particle size distribution was used. Sample No. 1 was sometimes broken in the intermittent cutting test, but showed a small wear width of less than 0.30 mm in the continuous cutting test and excellent wear resistance.
[0039]
On the other hand, the sample No. 8, 9 are outside the scope of the present invention. That is, the sample No. 8 has no particle size distribution, and the average particle size of the Zr compound in the surface layer having a thickness of 50 μm from the surface of the cemented carbide base material is less than 0.02 μm, and the wear width of the continuous cutting test is 0.50 mm. Yes, and it was easy to cut in the intermittent cutting test. Further, the sample No. No. 9 does not have the above-mentioned particle size distribution, and the average particle size of the Zr compound in the inner core which is inside 150 μm from the surface of the cemented carbide base material is as large as 10.0 μm. Was small, but 90% was lost in the intermittent cutting test.
[0040]
【The invention's effect】
As described above, according to the coated cemented carbide of the present invention, in a coated cemented carbide in which a coating layer is applied to the surface of a cemented carbide base material, the hard phase is an oxide of Zr and / or Hf; Carbide, nitride, and a compound containing at least one of carbonitrides, and the average particle size of the compound is 0.02 to 0.5 μm in a region at a depth of 50 μm from the surface of the cemented carbide base material. , 150 μm depth region is 1.0 to 5.0 μm, so that when used as a cutting tool, toughness, hardness and plastic deformation resistance at high temperatures are dramatically improved, , Which withstands high-speed cutting. Further, the present invention can be stably applied to dry cutting under severe conditions, which has been almost impossible in the past.
[0041]
Thus, the coated cemented carbide according to the present invention more than sufficiently meets the demand for high-efficiency machining in the cutting of metal members and the requirement for consideration for the environment without using cutting oil for cutting edge cooling. Things.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14699899A JP3544632B2 (en) | 1999-05-26 | 1999-05-26 | Coated cemented carbide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14699899A JP3544632B2 (en) | 1999-05-26 | 1999-05-26 | Coated cemented carbide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000336489A JP2000336489A (en) | 2000-12-05 |
| JP3544632B2 true JP3544632B2 (en) | 2004-07-21 |
Family
ID=15420286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14699899A Expired - Fee Related JP3544632B2 (en) | 1999-05-26 | 1999-05-26 | Coated cemented carbide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3544632B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009120902A (en) * | 2007-11-14 | 2009-06-04 | Sumitomo Electric Ind Ltd | Laminated structure type cemented carbide, its manufacturing method, and tool made of the cemented carbide |
-
1999
- 1999-05-26 JP JP14699899A patent/JP3544632B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000336489A (en) | 2000-12-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0569696B1 (en) | Coated cemented carbide members and method of manufacturing the same | |
| JPS6348836B2 (en) | ||
| US6140262A (en) | Polycrystalline cubic boron nitride cutting tool | |
| JP2007229821A (en) | Surface-coated cutting tool | |
| WO2010104094A1 (en) | Cermet and coated cermet | |
| JPH08209336A (en) | Coated hard alloy | |
| JPS61101482A (en) | Silicon nitride cutting tool | |
| JPH0196083A (en) | Surface-coated cubic boron nitride based material sintered under superhigh pressure to be used for cutting tool | |
| JP3544632B2 (en) | Coated cemented carbide | |
| JP2006305708A (en) | Sialon throw-away tip, and cutting tool | |
| JP2005047004A (en) | Composite high-hardness material for tool | |
| JP3235259B2 (en) | Coated cemented carbide member and method of manufacturing the same | |
| JP2596094B2 (en) | Surface-coated ceramic cutting tool with excellent wear resistance | |
| JP3611184B2 (en) | Ceramic sintered body cutting tool for cast iron machining and coated ceramic sintered body cutting tool for cast iron machining | |
| JPH02275763A (en) | Silicon nitride-base sintered material | |
| JP2849055B2 (en) | Sialon-based sintered body and coated sintered body | |
| JP4428805B2 (en) | Aluminum oxide-containing composite ceramic sintered body and coated composite ceramic sintered body | |
| JP3519324B2 (en) | Ceramic sintered body and coated ceramic sintered body | |
| JPH10310878A (en) | Cutting tool made of surface-coated cemented carbide having hard coating layer excellent in wear resistance | |
| JP2604155B2 (en) | Ceramic tool with coating layer | |
| JP3009310B2 (en) | Sialon-based sintered body and its coated sintered body | |
| JP2570354B2 (en) | Surface coated ceramic members for cutting tools | |
| JP2000038637A (en) | End mill made of surface-coated cemented carbide in which substrate has high toughness | |
| JPH06298568A (en) | Whisker-reinforced sialon-based sintered compact and sintered and coated material | |
| JP2007136653A (en) | Surface coated cutting tool made of cubic boron nitride-base ultra-high pressure sintered material having hard coated layer exhibiting chipping resistance in high-speed heavy cutting of high-hardness steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20040330 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20040405 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080416 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090416 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090416 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100416 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110416 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110416 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120416 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120416 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130416 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140416 Year of fee payment: 10 |
|
| LAPS | Cancellation because of no payment of annual fees |