JP2004315950A

JP2004315950A - Heat resistant and wear resistant member, and its production method

Info

Publication number: JP2004315950A
Application number: JP2003115293A
Authority: JP
Inventors: Kesanori Imi; 今朝則伊美; Masatoshi Ayagaki; 昌俊綾垣
Original assignee: Yoshikawa Kogyo Co Ltd; Nippon Steel Corp
Current assignee: Yoshikawa Kogyo Co Ltd; Nippon Steel Corp
Priority date: 2003-04-21
Filing date: 2003-04-21
Publication date: 2004-11-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat resistant and wear resistant member which is brought into contact with a high temperature material and particularly requires high toughness, such as a roll and a roller, e.g., used in a rolling factory in an iron manufacturing field, and to provide its production method. <P>SOLUTION: The heat resistant and wear resistant member is obtained by forming a HIP (hot isostatic press) treatment layer consisting of one or more selected from the carbide, nitride, oxide, and boride of metal, a high speed steel, and an Ni-B based self-fluxing alloy on a base material consisting of a carbon steel so as to be a multilayer structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、製鉄分野などにおいて、例えば圧延工場等で使用されているロール、ローラーなどのように高温材料と接触し、特に大きな靭性を必要とする耐熱耐摩耗部材及びその製造方法に関するものである。
【０００２】
【従来の技術】
一般に耐熱耐摩耗部材には高硬度が要求され、かつ熱衝撃や機械的衝撃に十分耐え得る強度、特に大きな靱性が要求される。このための従来の技術として、例えば特開平１０−２８０１０１号公報（特許文献１）に開示されている。この技術の概要は、炭素鋼からなる母材に金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上と高速度鋼（以下、ハイスと称す）の合金とからなるＨＩＰ処理層を形成し多層構造としたことを特徴とする耐熱耐摩耗部材である。すなわち、ハイス粉末とセラミックス粉末とをメカニカルアロイング（以下、ＭＡと称す）後、ＨＩＰ法にて前記の固相焼結相を炭素鋼の表面に形成するものであり、これにより、耐摩耗性、耐肌荒れ性が向上する。
【０００３】
【引用文献】
（１）特許文献１（特開平１０−２８０１０１号公報）
【０００４】
【発明が解決しようとする課題】
しかしながら、前記特許文献１に開示されている技術内容のものでは、使用環境、例えば前記圧延工場などで使用されているロール、ローラーなどのように高温材料と接触するものにおいては、その靭性が充分でなく、使用時に亀裂が発生することがあり、操業を停止せざるを得ない。
以上述べたような従来技術の課題に鑑み、本発明の目的は、高温材料と接触し、特に大きな靭性を必要とする耐熱耐摩耗部材及びその製造方法を提供する。
【０００５】
【課題を解決するための手段】
本発明は、上記の課題を解決するために発明されたもので、その発明の要旨とするところは、
（１）炭素鋼からなる母材に、金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上と高速度鋼とＮｉ−Ｂ系自溶性合金とからなるＨＩＰ処理層を形成し多層構造としたことを特徴とする耐熱耐摩耗部材。
【０００６】
（２）予めハイス粉末に体積％で５〜４５％の金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上からなる粉末とをメカニカルアロイング法により合金化し、その後、前記合金化物と質量％で、１〜６％のＮｉ−Ｂ系の自溶性合金粉末とを混合した後、炭素鋼からなる母材の表面へ温度１０００〜１２００℃、圧力１００ＭＰａ以上、２〜５時間のＨＩＰ処理を行い多層構造としたことを特徴とする耐熱耐摩耗部材の製造方法。
【０００７】
（３）ハイス粉末に体積％で５〜４５％の金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上からなる粉末を、さらに、前記両者に対し、質量％で１〜６％のＮｉ−Ｂ系の自溶性合金粉末とからなる３者をメカニカルアロイング法により合金化し、その後、炭素鋼からなる母材の表面へ温度１０００〜１２００℃、圧力１００ＭＰａ以上、２〜５時間のＨＩＰ処理を行い多層構造としたことを特徴とする耐熱耐摩耗部材の製造方法である。
【０００８】
【発明の実施の形態】
以下、本発明について詳細に説明する。
本発明では従来の技術である前記特許文献１に開示されている組織、すなわち、ハイス材と硬質でかつ化学的に安定な炭化物、窒化物、酸化物、ホウ化物からなる１種以上を微細に分散させた組織にＮｉ−Ｂ系の合金を液相焼結させることにより、該焼結品は、微細分散されたサーメット組織となり、これにより、前記の従来材質に比し、靭性及び耐摩耗性・耐肌荒性を大幅に向上させることが可能となった。
【０００９】
自溶性合金粉末としては、種々の自溶性粉末の中、Ｎｉ−Ｂ系の合金粉末が液相を出現させやすく、Ｎｉ−Ｂ、Ｆｅ−Ｎｉ−Ｂ等、Ｂとの共晶反応により低融点化を図っている点から適している。また、その添加量については、ハイス粉末と炭化物、窒化物、酸化物からなる１種以上の粉末との質量割合が１％より少ないとサーメット組織の分散が不十分で靭性、耐摩耗・耐肌荒性の改善効果が充分でなく、他方、６％を超えると前記組織が粗大で且つ、硬度が低下するので耐摩耗・耐肌荒性・靭性を充分に確保することができない。従って、Ｎｉ−Ｂ系の合金粉末の適切なる添加量としては、質量比で１〜６％が好ましい。
次に、ハイス粉末に対する炭化物、窒化物、酸化物からなる１種以上の粉末の体積％が、５％より少ないと耐摩耗性改善効果が充分でないため好ましくなく、他方、４５％を超えると靭性が低下する。従って、前記粉末の適切なる添加量としては、ハイス粉末に対して、体積％で５〜４５％が好ましい。
【００１０】
次に、ハイス粉末の成分限定理由について、以下に説明する。
Ｃ：０．９〜２．５％
Ｃは、焼入性を向上させ、マトリックス硬度を高くし、Ｃｒ，Ｍｏ，Ｖ，Ｗと高硬度の炭化物を形成し、耐摩耗性を向上させる。０．９％未満では炭化物量が少なく、硬度、耐摩耗性の向上は期待できない。また、２．５％を越えると、靱性が低下するため好ましくない。
【００１１】
Ｓｉ：０．２〜１．５％
Ｓｉは、粉末製造の原料となる溶湯中の酸素と化合し脱酸効果があり、清浄な粉末を製造するために必要である。０．２％未満ではその効果がなく、１．５％を越えると、その効果は変わらないため上限を１．５％とした。
Ｍｎ：０．３〜２．０％
Ｍｎは、粉末製造の原料溶湯中のＳを固定し、有害物質の発生を防止する。また、焼入性を高め、マトリックス硬度の増加に寄与する。０．３％未満ではその効果はなく、２．０％を越えると、その効果が変わらない。
【００１２】
Ｃｒ：３．５〜１２．０％
Ｃｒは、マトリックスの焼入性を向上させ、硬度を上げるとともに、炭化物をつくり全体硬度の向上に寄与する。３．５％未満ではその効果は無く、１２．０％を越えると炭化物の粗大化による靱性が低下するため、耐衝撃性が損なわれる。
Ｍｏ：３．０〜１０．０％
Ｍｏは、マトリックスの焼入性を高めるとともに、安定な炭化物を形成し、全体の硬度向上に寄与し耐摩耗性を向上する。３．０％未満では効果が無く、１０％を越えても効果は変わらないため、上限を１０．０％とした。
【００１３】
Ｖ：０．８〜８．０％
Ｖは、炭素と化合し、高硬度の微細なＶＣ炭化物を晶出し、耐摩耗性向上の効果が高い元素である。０．８％未満では効果が無く、８．０％を越えると、マトリックス中の固溶炭化物量が減少するためマトリックス硬度を下げるので好ましくない。
Ｗ：１．０〜１０．０％
Ｗは、炭素と化合し高硬度の炭化物を形成し耐摩耗性を高めるが１．０％未満では効果が無く、１０．０％を越えると炭化物が粗大化し、靱性低下、耐衝撃性の低下につながり好ましくない。
【００１４】
なお、Ｎｉについては必須の成分ではないが、焼入性を向上させ、マトリックス硬度を高める効果がある。ただし、３．０％を越えると残留オーステナイトが増え、硬度低下を招くので好ましくない。Ｃｏについても必須成分ではないが、炭素の固溶を促進しマトリックスの焼入性を高め、マトリックス硬度を増加させる効果がある。しかし、１０．０％を越えると残留オーステナイト量が増え、マトリックス硬度が低下するので好ましくない。
【００１５】
次に、本発明で用いるＭＡについて説明する。ＭＡは鋼球やセラミックス製のボールによって、前記特許文献１に開示されているように、混合粉末の粉末砕、固着を繰り返すことによって異種材料を原子レベルで合金化することができる。
本発明におけるＨＩＰ処理前の事前方法としては、以下の２つが適している。要求特性、コスト面、工期等を考慮し、適宜選定・実施するとよい。
（１）予めハイス粉末と金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上の粉末からなる２者をＭＡにより合金化し、その後、前記合金化物とＮｉ−Ｂ系の自溶性合金粉末とを混合した後、ＨＩＰ処理する方法。この方法の特徴は、予めハイスサーメット粉を大量に作成し、Ｎｉ−Ｂ系粉の添加量を種々変更することにより使用特性（用途）に適合する造り分けを容易に実施できる。従って、短納期での適正なる材料の提供が容易に可能である。
【００１６】
（２）前記ハイス粉末と金属の炭化物、窒化物、酸化物、ホウ化物のうちの１種以上の粉末からなる２者に加え、Ｎｉ−Ｂ系の自溶性合金粉末からなる合計３者をＭＡにより合金化し、その後、ＨＩＰ処理する方法。この方法の特徴は、工程がシンプルであり、且つ、ＨＩＰ処理前でのＭＡにより合金が微細化されるためＨＩＰ後の焼結体の結晶粒径が極めて微細となり、その結果、前記（１）の方法に比し、破壊靭性、耐摩耗性、耐肌荒れ性が優れる。
【００１７】
一般に粉末を用いた場合、鋳造材に比べて高コストとなるので、極力、粉末使用量を抑えることが重要である。そこで本発明では実際の使用時に相手材と接触し耐摩耗性、耐衝撃性が必要な外層にのみ粉末冶金材料を用い、耐摩耗性の必要が無い母材には安価で高靱性の炭素鋼を用いた２層構造とすることによってコスト低減を実現している。なお、使用条件が極めて厳しい素材として適用の場合、前記２層構造材である炭素鋼である母材と外層材との間に、中間層材として、金属ハイスを形成することにより該境界部の信頼性がより向上するため好ましい。
【００１８】
また、粉末の焼結にはＨＩＰ法を用いているが、これはＨＩＰでは、高温高圧下による粉末の塑性変形によって粉末間の間隙をつぶすため、通常の焼結助剤を用いた焼結法に比して、極めて欠陥の少ない強度特性に優れた材料の製造が可能となる。さらに焼結と同時に外層材料と母材との境界に原子拡散を生じせしめ冶金的結合を形成し、強固な密着力を得ることが可能である。
【００１９】
次に、本発明材におけるＨＩＰ条件について、以下に説明する。
ＨＩＰ温度が１０００℃未満の場合は、Ｎｉ−Ｂの溶融反応が不十分で、サーメットの分散組織が得られず、また気孔が残こることもあり、好ましくない。他方、１２００℃を越えると、粒子が粗大化し強度が減少するので上限を１２００℃とした。圧力は１００ＭＰａ以上であれば気孔を消失せしめるには十分である。また、処理時間は２時間以上で十分密な焼結組織が得られるが５時間を越えると組織が粗大化するため好ましくない。
【００２０】
【実施例】
以下、本発明について実施例によって具体的に説明する。
本発明の作用、効果を確証するため、表１に示す本発明例Ｎｏ．１〜８、および比較例Ｎｏ．９〜１２、並びに従来例Ｎｏ．１３の試験片を各々製作し、前記表１に示している各種の材料特性を測定した。以下、表１〜３及び図１〜７を用いてその内容及び結果について説明する。表１に示すＨＩＰ処理前の事前処理としては、使用した粉末、すなわち、ハイス粉末としては表２に示す化学成分のハイス粉末を、硬質炭化物粉末としてはＴｉＣ粉末を、自溶性合金粉末としては、表３に示す化学成分のＮｉ−Ｂ合金粉末を各々使用した。
【００２１】
【表１】

【００２２】
【表２】

【００２３】
【表３】

【００２４】
表１に示す本発明例Ｎｏ．１〜４、比較例Ｎｏ．９〜１０において、前記ハイス粉末として表１に各々示す質量％と前記セラミック粉末を一定の質量％である６％（体積％＝１０％）とをＳＵＪ２鋼製のボールを用いたＭＡによって３０時間の合金化作業を行った。その後、前記合金化物に、前記表１に各々示す質量％のＮｉ−Ｂ合金粉末を各々混合し、ＨＩＰ処理前の事前処理工程を終了した。
【００２５】
また、前記表１に示す本発明例Ｎｏ．５〜８、比較例Ｎｏ．１１〜１２において、前記ハイス粉末として表１に各々示す質量％と前記セラミック粉末を一定の質量％である６％（体積％＝１０％）と表１に各々示す質量％のＮｉ−Ｂ合金粉末とを前記と同様に、ＳＵＪ２鋼製のボールを用いたＭＡによって３０時間の合金化作業を行いＨＩＰ処理前の事前処理工程工程を終了した。
また、残りの表１に示す、従来例であるＮｏ．１３において、前記ハイス粉末として表１に各々示す質量％と前記ＴｉＣ粉末を一定の質量％である６％（体積％＝１０％）とをＳＵＪ２鋼製のボールを用いたＭＡによって３０時間の合金化作業を行い、これによりＨＩＰ処理前の事前処理工程を終了した。
【００２６】
ＨＩＰ処理（摩耗・硬度・破壊靭性試験用の試験片の製作等）については、図４に示す炭素鋼管１からなるカプセル４中に、母材である芯材２として低合金炭素鋼ＳＣＭ４４０を配置し、その周囲に前記事前処理の終了したＮｏ．１〜１３の合金化物を充填し、その後、脱気パイプ５から、真空脱気後、１１８０℃、１２０ＭＰａ、３時間のＨＩＰ処理を行い、軟化焼鈍後、粗加工を施した。焼き入れは１０５０℃×２時間のオーステナイト後、常温まで冷却した後、５５０℃×３．５時間で３回焼戻した。以上により、摩耗試験・硬度測定・破壊靭性用の試験片素材の製作が完了した。
【００２７】
耐摩耗性は、図５に示す熱間摩耗試験にて実施・評価した。図５における試験片７としては、前記のとおり製作した１３種類の試験片から、リング形状（φ６０×１０ｔｍｍ）に加工した本材料を切り出し、相手材８としては、（Ｓ４５Ｃ鋼：φ１８０×１５ｔｍｍ）に押しつけながら回転させ、一定回転数後の摩耗量で、耐摩耗性を評価した。試験中は、試験材７の温度を５００℃、相手材８の温度を加熱コイル９の作用で、８５０℃−定に保った。回転速度は７００ｒｐｍ、押しつけ荷重は５０ｋｇで、１００００回転後の摩耗重量及び表面租度を測定した。その試験結果を表１及び図６に示す。
【００２８】
以下、試験結果について、表１及び図６を用いて前記試験結果について詳述する。図６は、本発明に係る試験結果を示す図であり、点線は表１におけるＮｏ．５〜８、１１、１２に示す粉末▲１▼、▲２▼、▲３▼同時ＭＡしたもの、連続実線は表１におけるＮｏ．１〜４、９、１０に示す粉末▲２▼＋▲３▼で同時ＭＡ後粉末▲１▼を混合した場合である。図６（ａ）は破壊靱性試験で、Ｎｉ−Ｂ添加量と破壊靱性値（Ｋ_ＩＣ）との関係を示し、図６（ｂ）は高温摩耗試験で、Ｎｉ−Ｂ添加量と表面粗度（μｍ）との関係を、また、図６（ｃ）はＮｉ−Ｂ添加量と耐摩耗比（％）との関係を示す図である。
【００２９】
この表１及び図６において、本発明例Ｎｏ．１〜８で示す本発明材の摩耗試験結果、すなわち、耐摩耗比及び肌荒れは、従来材であるＮｏ．１３と比べ、耐摩耗比は大きく、肌荒れは小さく、いずれも優れていることが明確である。また、機械的性質である破壊靭性値についても．前記と同様に本発明材であるＮｏ．１〜８が従来材であるＮｏ．１３と比べ、その値が大きく優れていることが明確である。
【００３０】
図１は、各々本発明材である表１におけるＮｏ．１のミクロ組織写真（×４００倍）を示す。同様に図２は、Ｎｏ．２の、図３は、Ｎｏ．５のミクロ組織写真（×４００倍）を示すものである。一方、図７は、従来材であるＮｏ．１３のミクロ組織写真（×４００倍）を示す。ここで、本発明材のミクロ写真である前記図１、２．３と従来材である図７とのミクロ組織を比較してみる。従来材のミクロ写真である前記図７においては、サーメット組織が面状をなしている。これに対し、本発明材である図１．２．３においては、サーメット中の硬質物が微細分散化されており、このミクロ写真からも前記本発明材の摩耗試験結果および破壊靭性が従来材に比べて優れているとの前記の説明が容易に理解できる。
【００３１】
また、前記本発明材のＮｏ．１〜８において、Ｎｏ．１〜４は、予めハイス粉末とセラミックス粉末との２者をＭＡ法により合金化した後、前記合金化物とＮｉ−Ｂ系の自溶性合金粉末とを混合した後、ＨＩＰ処理を行ったものであり、残りのＮｏ．５〜８は、ハイス粉末とセラミックス粉末とＮｉ−Ｂ系の自溶性合金粉末との３者をＭＡ法により合金化し、その後、ＨＩＰ処理を行ったものである。ここで、両者を比較してみると、原材料が同一且つ混合する質量割合％が同じでも前記Ｎｏ．５〜８の方法で処理をした方が、前記Ｎｏ．１〜４の方法で処理をした分より、いずれも、材料特性が優れていることが明確であり、前述した通りの試験結果となっていることが明らかである。
【００３２】
Ｎｏ．９〜１０は、前記本発明例のＮｏ．１〜４に対する比較例であり、同様にＮｏ．１１〜１２は、前記本発明例のＮｏ．５〜８に対する比較例である．両者を比較してみると、Ｎｉ−Ｂ系の自溶性合金粉末が、本発明材の適正範囲を外れている比較例Ｎｏ．９〜１２では、いずれも本発明材Ｎｏ．１〜８に比し、表１及び図６に示されているようにその材料特性が劣っていることが明確である。
【００３３】
【発明の効果】
以上述べたように、本発明によって、耐熱耐摩耗性及び耐事故性（強靭性）が要求される使用環境で有効な材料、部材を提供することができ、寿命向上によってライン整備費等のコスト軽減に寄与できる。
【図面の簡単な説明】
【図１】本発明材のミクロ組織（×４００倍）を示す顕微鏡写真である。
【図２】本発明材の他のミクロ組織（×４００倍）を示す顕微鏡写真である。
【図３】本発明材の他のミクロ組織（×４００倍）を示す顕微鏡写真である。
【図４】本発明の試験時の（ＨＩＰカプセル）を示す概要図である。
【図５】本発明の試験時の摩耗試験機の概要図である。
【図６】本発明に係る試験結果を示す図である。
【図７】従来材のミクロ組織（×４００倍）を示す顕微鏡写真である。
【符号の説明】
１炭素鋼管
２芯材
３粉末
４カプセル
５脱気パイプ
６溶接シール
７試験片
８相手材（圧延材相当）
９加熱コイル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat-resistant and wear-resistant member that contacts a high-temperature material such as a roll or a roller used in a rolling mill or the like and particularly requires a large toughness in a steelmaking field or the like, and a method for manufacturing the same. .
[0002]
[Prior art]
Generally, a heat-resistant and wear-resistant member is required to have high hardness, and strength that can sufficiently withstand thermal shock and mechanical shock, particularly large toughness. A conventional technique for this purpose is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-280101 (Patent Document 1). The outline of this technology is a HIP treatment layer comprising a base material made of carbon steel and an alloy of one or more of metal carbides, nitrides, oxides, and borides and a high-speed steel (hereinafter, referred to as high-speed steel). The heat and wear resistant member is characterized by having a multilayer structure formed by forming That is, after the high-speed powder and the ceramic powder are mechanically alloyed (hereinafter, referred to as MA), the solid phase sintering phase is formed on the surface of the carbon steel by the HIP method. The resistance to rough skin is improved.
[0003]
[References]
(1) Patent Document 1 (JP-A-10-280101)
[0004]
[Problems to be solved by the invention]
However, in the technology disclosed in Patent Document 1, in a use environment, for example, a material that comes into contact with a high-temperature material such as a roll or a roller used in the rolling mill, the toughness is not sufficient. In addition, cracks may occur during use, and the operation must be stopped.
In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a heat-resistant and wear-resistant member that comes into contact with a high-temperature material and requires particularly high toughness, and a method for manufacturing the same.
[0005]
[Means for Solving the Problems]
The present invention has been invented to solve the above problems, and the gist of the invention is as follows:
(1) Forming a HIP treatment layer comprising at least one of metal carbides, nitrides, oxides and borides, a high-speed steel and a Ni-B-based self-fluxing alloy on a carbon steel base material. A heat and wear resistant member having a multilayer structure.
[0006]
(2) An alloy of 5% to 45% by volume of a metal carbide, nitride, oxide, or boride is previously alloyed to a high-speed powder by mechanical alloying, and then the alloy is formed. Of Ni-B-based self-fluxing alloy powder of 1 to 6% by mass and a mass%, and then a temperature of 1000 to 1200 ° C., a pressure of 100 MPa or more, and a pressure of 2 to 5 hours are applied to the surface of the base material made of carbon steel. A method for producing a heat-resistant and wear-resistant member, wherein the member is subjected to HIP treatment to form a multilayer structure.
[0007]
(3) 5 to 45% by volume of a metal carbide, nitride, oxide, or boride powder of at least 1% of metal carbide, nitride, oxide or boride, and 1 to 6% by mass with respect to both. % Ni-B-based self-fluxing alloy powder and alloyed by mechanical alloying, and thereafter, a temperature of 1000 to 1200 ° C., a pressure of 100 MPa or more, and a pressure of 100 MPa or more for 2 to 5 hours. HIP treatment to form a multilayer structure.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, the structure disclosed in Patent Document 1 which is a conventional technique, that is, one or more kinds of high-speed steel and hard and chemically stable carbides, nitrides, oxides, and borides are finely divided. By performing liquid phase sintering of the Ni-B alloy on the dispersed structure, the sintered product has a finely dispersed cermet structure, and thus has a higher toughness and abrasion resistance than the conventional materials.・ It has become possible to greatly improve skin roughness resistance.
[0009]
Among the self-fluxing alloy powders, among various self-fluxing powders, Ni-B-based alloy powders easily cause a liquid phase to appear, and have a low melting point due to a eutectic reaction with B, such as Ni-B and Fe-Ni-B. It is suitable from the point of achieving the goal. If the mass ratio of the high-speed powder and one or more powders of carbides, nitrides and oxides is less than 1%, the dispersion of the cermet structure is insufficient and the toughness, abrasion resistance and skin resistance are insufficient. If the effect of improving the roughness is not sufficient, on the other hand, if it exceeds 6%, the structure is coarse and the hardness is reduced, so that it is not possible to sufficiently secure wear resistance, skin roughness resistance and toughness. Therefore, the appropriate addition amount of the Ni-B-based alloy powder is preferably 1 to 6% by mass.
Next, if the volume percentage of one or more powders of carbides, nitrides, and oxides with respect to the HSS powder is less than 5%, the effect of improving wear resistance is not sufficient, and if it exceeds 45%, the toughness is increased. Decreases. Therefore, an appropriate amount of the powder to be added is preferably 5 to 45% by volume based on the HSS powder.
[0010]
Next, the reasons for limiting the components of the HSS powder will be described below.
C: 0.9-2.5%
C improves hardenability, increases matrix hardness, forms carbides of high hardness with Cr, Mo, V, and W, and improves wear resistance. If it is less than 0.9%, the amount of carbide is small, and improvement in hardness and wear resistance cannot be expected. On the other hand, if it exceeds 2.5%, the toughness is undesirably reduced.
[0011]
Si: 0.2-1.5%
Si has a deoxidizing effect by being combined with oxygen in a molten metal which is a raw material of powder production, and is necessary for producing clean powder. If it is less than 0.2%, there is no effect, and if it exceeds 1.5%, the effect does not change, so the upper limit is made 1.5%.
Mn: 0.3-2.0%
Mn fixes S in the raw material melt for powder production and prevents generation of harmful substances. In addition, it enhances hardenability and contributes to an increase in matrix hardness. If it is less than 0.3%, there is no effect, and if it exceeds 2.0%, the effect does not change.
[0012]
Cr: 3.5 to 12.0%
Cr improves the hardenability of the matrix, increases the hardness, and forms carbide to contribute to the improvement of the overall hardness. If it is less than 3.5%, the effect is not obtained, and if it exceeds 12.0%, the toughness is reduced due to coarsening of the carbide, and the impact resistance is impaired.
Mo: 3.0 to 10.0%
Mo enhances the hardenability of the matrix, forms a stable carbide, contributes to the improvement of the overall hardness, and improves the wear resistance. If it is less than 3.0%, there is no effect, and if it exceeds 10%, the effect does not change. Therefore, the upper limit is set to 10.0%.
[0013]
V: 0.8-8.0%
V is an element that combines with carbon to crystallize fine VC carbides having high hardness and has a high effect of improving wear resistance. If it is less than 0.8%, there is no effect, and if it exceeds 8.0%, the amount of solid-dissolved carbide in the matrix is reduced, so that the hardness of the matrix is undesirably lowered.
W: 1.0 to 10.0%
W combines with carbon to form carbides of high hardness and enhances wear resistance, but if less than 1.0%, there is no effect. If it exceeds 10.0%, carbides become coarse, and toughness and impact resistance decrease. Undesirably leads to
[0014]
Although Ni is not an essential component, it has an effect of improving hardenability and increasing matrix hardness. However, when the content exceeds 3.0%, retained austenite increases, which causes a decrease in hardness, which is not preferable. Co is not an essential component, but has the effect of promoting solid solution of carbon, increasing the hardenability of the matrix, and increasing the matrix hardness. However, if it exceeds 10.0%, the amount of retained austenite increases and the matrix hardness decreases, which is not preferable.
[0015]
Next, the MA used in the present invention will be described. MA is capable of alloying different materials at the atomic level by repeatedly crushing and fixing the mixed powder as disclosed in Patent Document 1 using steel balls or ceramic balls.
In the present invention, the following two methods are suitable as the prior methods before the HIP processing. It is advisable to select and implement as appropriate in consideration of required characteristics, cost, construction period, etc.
(1) A high-speed powder and one or more powders of carbides, nitrides, oxides and borides of metal are alloyed by MA beforehand, and then the alloyed material and the Ni-B based self-solubility A method of performing HIP treatment after mixing with an alloy powder. The feature of this method is that a large amount of high-speed cermet powder is prepared in advance, and the amount of addition of the Ni-B-based powder is variously changed, so that it is possible to easily carry out the production suitable for use characteristics (use). Therefore, it is possible to easily provide an appropriate material with a short delivery time.
[0016]
(2) In addition to two of the above-mentioned high-speed powder and one or more powders of carbides, nitrides, oxides, and borides of metals, a total of three of the Ni-B based self-fluxing alloy powders is MA. And then HIPing. The feature of this method is that the steps are simple and the alloy is refined by MA before HIP treatment, so that the crystal grain size of the sintered body after HIP becomes extremely fine. As compared with the method of (1), the fracture toughness, abrasion resistance and skin roughness resistance are excellent.
[0017]
In general, when powder is used, the cost is higher than that of a cast material. Therefore, it is important to minimize the amount of powder used. Therefore, in the present invention, powder metallurgical material is used only for the outer layer that needs to have abrasion resistance and impact resistance when it comes into contact with the counterpart material during actual use, and a low-cost, high-toughness carbon steel is used for the base material that does not require abrasion resistance. A cost reduction is realized by adopting a two-layer structure using. In the case where the material is used as a material under extremely severe conditions, a metal high-speed steel is formed as an intermediate layer material between the base material, which is carbon steel, which is the two-layer structure material, and the outer layer material, thereby forming the boundary portion. This is preferable because the reliability is further improved.
[0018]
In addition, the HIP method is used for sintering the powder. In the HIP method, since the gap between the powders is crushed by plastic deformation of the powder under high temperature and high pressure, a sintering method using a normal sintering aid is used. As a result, it is possible to produce a material having very few defects and excellent strength characteristics. Further, at the same time as sintering, atomic diffusion is caused at the boundary between the outer layer material and the base material to form a metallurgical bond, and a strong adhesion can be obtained.
[0019]
Next, the HIP conditions in the material of the present invention will be described below.
If the HIP temperature is lower than 1000 ° C., the melting reaction of Ni—B is insufficient, a dispersed structure of cermet cannot be obtained, and pores may remain, which is not preferable. On the other hand, if the temperature exceeds 1200 ° C., the particles become coarse and the strength decreases, so the upper limit was set to 1200 ° C. A pressure of 100 MPa or more is sufficient for eliminating pores. When the treatment time is 2 hours or more, a sufficiently dense sintered structure can be obtained, but if it exceeds 5 hours, the structure is undesirably coarse.
[0020]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples.
In order to confirm the operation and effect of the present invention, the present invention example No. 1 shown in Table 1 was used. Nos. 1 to 8 and Comparative Example Nos. Nos. 9 to 12 and Conventional Example Nos. Thirteen test pieces were manufactured, and various material properties shown in Table 1 were measured. Hereinafter, the contents and results will be described with reference to Tables 1 to 3 and FIGS. As the pre-treatment before the HIP treatment shown in Table 1, the powder used, that is, the HSS powder having the chemical composition shown in Table 2 as the HSS powder, the TiC powder as the hard carbide powder, and the self-fluxing alloy powder as Ni-B alloy powders having the chemical components shown in Table 3 were used.
[0021]
[Table 1]

[0022]
[Table 2]

[0023]
[Table 3]

[0024]
Example 1 of the present invention shown in Table 1. Nos. 1 to 4, Comparative Example Nos. In 9 to 10, the mass% shown in Table 1 as the high-speed powder and the ceramic powder at a constant mass percentage of 6% (volume% = 10%) were 30 hours by MA using SUJ2 steel balls. Alloying work was performed. Thereafter, Ni-B alloy powders of each mass% shown in Table 1 were mixed with the alloyed product, and the pre-treatment step before the HIP treatment was completed.
[0025]
In addition, the present invention example No. shown in Table 1 above. 5 to 8, Comparative Example Nos. 11-11, Ni-B alloy powders having the mass% shown in Table 1 as the high-speed powder and the ceramic powder having a constant mass% of 6% (volume% = 10%) and the mass% shown in Table 1 respectively. In the same manner as described above, an alloying operation was performed for 30 hours by MA using SUJ2 steel balls, and the pretreatment step before the HIP treatment was completed.
Further, in the remaining Table 1, No. 1 which is a conventional example. In 13, the mass% shown in Table 1 as the high-speed powder and the constant mass% of 6% (volume% = 10%) of the TiC powder were alloyed for 30 hours by MA using SUJ2 steel balls. A pretreatment step before the HIP treatment was completed.
[0026]
Regarding the HIP treatment (production of a test piece for a wear / hardness / fracture toughness test, etc.), a low alloy carbon steel SCM440 is disposed as a core material 2 as a base material in a capsule 4 made of a carbon steel pipe 1 shown in FIG. No. around which the pre-processing has been completed. The alloyed materials of Nos. 1 to 13 were filled, and thereafter, after deaeration from the deaeration pipe 5, HIP treatment was performed at 1180 ° C. and 120 MPa for 3 hours. After softening and annealing, rough processing was performed. The quenching was performed after austenite at 1050 ° C. × 2 hours, cooled to room temperature, and then tempered three times at 550 ° C. × 3.5 hours. As described above, the production of the test specimen material for the wear test, the hardness measurement, and the fracture toughness was completed.
[0027]
Wear resistance was evaluated by a hot wear test shown in FIG. As the test piece 7 in FIG. 5, this material processed into a ring shape (φ60 × 10 tmm) was cut out from the 13 types of test pieces manufactured as described above, and the mating material 8 was (S45C steel: φ180 × 15 tmm). ) And rotated while being pressed against it, and the wear resistance after a certain number of rotations was evaluated for wear resistance. During the test, the temperature of the test material 7 was kept at 500 ° C., and the temperature of the mating material 8 was kept at 850 ° C.-constant by the action of the heating coil 9. The rotation speed was 700 rpm, the pressing load was 50 kg, and the abrasion weight and surface roughness after 10,000 rotations were measured. The test results are shown in Table 1 and FIG.
[0028]
Hereinafter, the test results will be described in detail with reference to Table 1 and FIG. FIG. 6 is a diagram showing the test results according to the present invention. The powders (1), (2), and (3) shown in Tables 5 to 8, 11, and 12 were subjected to simultaneous MA. This is the case where powder (1) after simultaneous MA was mixed with powder (2) + (3) shown in 1-4, 9 and 10. FIG. 6A is a fracture toughness test showing the relationship between the amount of Ni-B added and the fracture toughness value (K _IC ). FIG. 6B is a high-temperature wear test showing the amount of Ni-B added and the surface roughness. FIG. 6C is a graph showing the relationship between the amount of Ni-B added and the wear resistance ratio (%).
[0029]
In Table 1 and FIG. The wear test results of the material of the present invention indicated by Nos. 1 to 8, ie, the wear resistance ratio and the surface roughness, were the same as those of the conventional material. As compared with No. 13, it is clear that the abrasion resistance ratio is large, the surface roughness is small, and all are excellent. Also, regarding the fracture toughness value, which is a mechanical property. In the same manner as described above, the material of the present invention, Nos. 1 to 8 are conventional materials. It is clear that the value is much better than that of No. 13.
[0030]
FIG. 1 shows Nos. In Table 1 which are the materials of the present invention. 1 shows a microstructure photograph (× 400). Similarly, FIG. 2 and FIG. 5 shows a microstructure photograph (× 400) of FIG. On the other hand, FIG. 13 shows a microstructure photograph (× 400). Here, the microstructures of FIGS. 1 and 2.3 which are micro photographs of the material of the present invention and FIG. 7 which is a conventional material are compared. In FIG. 7, which is a microphotograph of the conventional material, the cermet structure is planar. On the other hand, in FIG. 1.2.3 which is the material of the present invention, the hard material in the cermet is finely dispersed, and the microphotograph shows that the wear test result and the fracture toughness of the material of the present invention are the same as those of the conventional material. The above description of superiority can be easily understood.
[0031]
In addition, in the case of the material of the present invention, In Nos. 1 to 8, Nos. 1 to 4 are obtained by previously alloying the high-speed powder and the ceramic powder by the MA method, mixing the alloyed material and the Ni-B-based self-fluxing alloy powder, and then performing HIP processing. And the remaining No. Nos. 5 to 8 are obtained by alloying a high-speed powder, a ceramic powder, and a Ni-B-based self-fluxing alloy powder by the MA method, and then performing HIP processing. Here, when the two are compared, even if the raw materials are the same and the mass ratio% to be mixed is the same, the above-mentioned No. 2 is obtained. Nos. 5 to 8 were more suitable for the treatment. It is clear that the material properties are excellent in all of the cases where the treatment is performed by the methods 1 to 4, and it is clear that the test results are as described above.
[0032]
No. Nos. 9 to 10 are Nos. Of the examples of the present invention. 4 are comparative examples for Nos. 1 to 4; Nos. 11 to 12 of the present invention examples. It is a comparative example with respect to 5-8. Comparing the two, the Ni-B-based self-fluxing alloy powder was found to be in Comparative Example No. In Nos. 9 to 12, all of the material Nos. Of the present invention. It is clear that the material properties are inferior to those of Nos. 1 to 8 as shown in Table 1 and FIG.
[0033]
【The invention's effect】
As described above, according to the present invention, it is possible to provide materials and members that are effective in a use environment in which heat resistance and wear resistance and accident resistance (toughness) are required. It can contribute to reduction.
[Brief description of the drawings]
FIG. 1 is a micrograph showing the microstructure (× 400 magnification) of the material of the present invention.
FIG. 2 is a micrograph showing another microstructure (× 400) of the material of the present invention.
FIG. 3 is a micrograph showing another microstructure (× 400) of the material of the present invention.
FIG. 4 is a schematic diagram showing a (HIP capsule) during a test of the present invention.
FIG. 5 is a schematic diagram of a wear tester during a test according to the present invention.
FIG. 6 is a diagram showing test results according to the present invention.
FIG. 7 is a micrograph showing a microstructure (× 400) of a conventional material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Carbon steel pipe 2 Core material 3 Powder 4 Capsule 5 Deaeration pipe 6 Weld seal 7 Test piece 8 Counterpart material (equivalent to rolled material)
9 heating coil

Claims

A multi-layer structure is formed by forming at least one of metal carbides, nitrides, oxides, and borides, a high-speed steel and a Ni—B-based self-fluxing alloy on a base material made of carbon steel, and a multilayer structure. A heat and wear resistant member characterized by the following.

5 to 45% by volume of a metal carbide, nitride, oxide, or boride powder is alloyed with a high-speed powder in advance by a mechanical alloying method. %, After mixing with 1 to 6% of a Ni-B based self-fluxing alloy powder, the surface of the base material made of carbon steel is subjected to HIP treatment at a temperature of 1000 to 1200 ° C. and a pressure of 100 MPa or more for 2 to 5 hours. A method for producing a heat- and wear-resistant member, characterized by having a multilayer structure.

5% to 45% by volume of a metal carbide, nitride, oxide, or boride powder is added to the HSS powder, and 1% to 6% of Ni -B-based self-fluxing alloy powder is alloyed by a mechanical alloying method, and then HIP treatment is performed on the surface of the base material made of carbon steel at a temperature of 1000 to 1200 ° C. and a pressure of 100 MPa or more for 2 to 5 hours. And producing a heat and wear resistant member having a multilayer structure.