JP4690553B2 - Mating ring for shift side guide roll - Google Patents

Mating ring for shift side guide roll Download PDF

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Publication number
JP4690553B2
JP4690553B2 JP2001001861A JP2001001861A JP4690553B2 JP 4690553 B2 JP4690553 B2 JP 4690553B2 JP 2001001861 A JP2001001861 A JP 2001001861A JP 2001001861 A JP2001001861 A JP 2001001861A JP 4690553 B2 JP4690553 B2 JP 4690553B2
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side guide
shift side
guide roll
particles
solid solution
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JP2002211981A (en
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重治 松林
哲郎 野瀬
伸一 吉野
明 露木
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Nippon Steel Corp
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Nippon Steel Corp
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Description

【0001】
【発明の属する技術分野】
本発明は、鋼板搬送ならびに巻き取り時の幅方向の位置決めに用いられるシフトサイドガイドロールに関する。
【0002】
【従来の技術】
鉄鋼製造設備においては、図1に示すように、酸洗ラインでコイルから鋼板を導出し(入り側)、酸に浸漬し、再びコイルに巻き取る(出側)際に鋼板2の幅方向の位置決め用に使われている2〜6本/組のロールをシフトサイドガイドロールと云われるロール1を前記酸洗ラインに組み込んでいる。従来から、焼き入れ鋼材(SUJ2、SNCM439など)にWC-Ni-Cr系の溶射を施したロールが使用されている。この設備は、φ150mm×L160mmまたはφ150mm×L270mmの大型ロールが数十本配備されている。厚さ1〜6mm、最も多い厚さは3mmの鋼板が、最高700m/分(=時速42km)の速度で通過するときに、鋼板の端面がロールを摺動しながらこのシフトサイドガイドロールによって幅方向の位置決めをされることになる。
【0003】
しかし、上記設備は上述したような構造となっているため、長さ160mmならびに270mmのいずれのロールであっても、ほぼ同一円周線上のみに押し付け負荷が加わり、不規則な振動を受け続けるなど、その使用環境は極めて厳しいものである。このため、このロールの材質としては、金属では耐久性に劣り、交換頻度が高いため、硬度が高く耐摩耗性に優れたセラミックスの適用が検討されている。
【0004】
これまで、窒化珪素質焼結体は、高温強度や硬度には優れた特性を有するものの、破壊靭性、耐摩耗性が劣り、実用的な材料とは言い難かった。そこで、窒化珪素質焼結体の高靭性化を図るために、各種粒子、ウィスカーを分散させる粒子分散窒化珪素質焼結体の研究開発が進められている。しかしながら、高硬度・耐摩耗性を維持できる材料系が殆ど無く、実用化を阻害している。同様に、炭化珪素質焼結体は、大気雰囲気下での高温強度や硬度には優れた特性を有するものの、破壊靭性、耐摩耗性が劣り、実用的な材料とは言い難かった。
【0005】
そこで、炭化珪素質焼結体の高靭性化を図るために、各種粒子、ウィスカーを分散させる粒子分散炭化珪素質焼結体の研究開発が進められている。しかしながら、高硬度・耐摩耗性を維持できる材料系が殆ど無く、実用化を阻害している。
【0006】
【発明が解決しようとする課題】
このように実際のロールの使用環境では、通板する際の高さ変動時の振動に対する機械的耐久性、ハンドリング時の耐欠損性等の機械的安定性にも優れている必要があり、上述の従来の問題点を解決し、いずれの要求特性にも極めて優れている材質を有する、酸洗ラインの幅方向位置決め用シフトサイドガイドロールを提供することを目的とする。
【0007】
【課題を解決するための手段】
本発明者等は、上記問題点を解決するために、窒化珪素ならびに炭化珪素セラミックス焼結体への分散粒子を鋭意検討した結果、特定の分散粒子を用いた場合に幅方向の位置決め用のシフトサイドガイドロール又は窒化珪素ならびに炭化珪素セラミックス焼結体からなるリングを少なくとも金属製シフトサイドガイドロールの鋼板との摺動部分に嵌合させる場合に優れた特性を有する焼結体が得られることを見出し、本発明を完成させるに至った。
【0008】
即ち、本発明は、
(1)窒化クロム(Cr2N)粒子を分散した窒化珪素を焼結した粒子分散窒化珪素質焼結体をリング状に成形加工して、該リングを少なくとも金属製シフトサイドガイドロールの鋼板との摺動部分に嵌合させてなることを特徴とする肉厚10mm以上20mm以下のシフトサイドガイドロール用嵌合リング
(2)前記窒化クロム(Cr2N)粒子の平均粒径が0.5〜10μmである請求項1記載シフトサイドガイドロール用嵌合リング
(3)前記窒化クロム(Cr2N)粒子の体積分率が1〜8%である請求項1記載シフトサイドガイドロール用嵌合リング
(4)前記粒子分散窒化珪素質焼結体の相対密度が99%以上である請求項1記載シフトサイドガイドロール用嵌合リング
(5)Ti-Zr-B固溶体粒子、Ti-Hf-B固溶体粒子の1種または2種を分散した炭化珪素を焼結した粒子分散炭化珪素質焼結体をリング状に成形加工して、該リングを少なくとも金属製シフトサイドガイドロールの鋼板との摺動部分に嵌合させてなることを特徴とする肉厚10mm以上20mm以下のシフトサイドガイドロール用嵌合リング
(6)前記Ti-Zr-B固溶体粒子の組成が、Ti1-xZrxB2(0.02≦x≦0.25)である請求項5記載シフトサイドガイドロール用嵌合リング
(7)前記Ti-Hf-B固溶体粒子の組成が、Ti1-xHfxB2(0.02≦x≦0.25)である請求項5記載シフトサイドガイドロール用嵌合リング
(8)前記固溶体粒子の平均粒径が1〜10μmである請求項5記載シフトサイドガイドロール用嵌合リング
(9)前記固溶体粒子の体積分率が20〜70%である請求項5記載シフトサイドガイドロール用嵌合リング
(10)前記粒子分散炭化珪素質焼結体の相対密度が99.5%以上である請求項5記載シフトサイドガイドロール用嵌合リング
【0009】
【発明の実施の形態】
以下に、本発明を詳細に説明する。
本発明者等は、従来使用されていた酸洗ラインの鋼板の幅方向位置決め用の焼き入れ金属にWC-Ni-Crを溶射したシフトサイドガイドロールについて、その損耗状況を鋭意解析した結果、鋼板が高速で通過する場合、硬度に劣る材料では、表面層が容易に摩耗し、消耗していくことを見い出した。また、摩耗部周囲には肌荒れが数多く認められることも見い出した。これらの摩耗と肌荒れは、シフトサイドガイドロールの硬度が低い場合に特に顕著に認められた。したがって、酸洗ラインの幅方向の位置決めロールを長期間安定して使用するためには、耐摩耗性と耐欠損性を同時に向上させることが必要で、そのためには硬度が高く、高靭性なセラミックス材にロールごと置き換えることを見い出した。但し、セラミックスでロール全体を製造する場合、製造コストが高くなるため、部分的な置き換えも合わせて検討を行った。
【0010】
その結果、鋼板との摺動面は鋼板の上下運動の高さによって変動するが、通常700m/分までの通板速度では、上方に+30mm、下方に-10mmまでの上下動の範囲に収まることが確認されている。したがって、安全率をそれぞれ20%程度見込み、帯状リングを嵌合させる場合は、50mm程度の帯高さを有することが好適である。また、セラミックス製リングを嵌合せしめる金属製のロール母体は焼入れによって高硬度化が容易なSUJ、SNCM439などの鋼種が好ましく、摺動するときに強度的に支障のない肉厚を有するセラミックスリングを嵌合し、接着・固定後に金属ロール母体との境界部に段差が生じないように円研加工を施すことが適している。
【0011】
そこで、これらの特性を同時に向上させるために、窒化珪素ならびに炭化珪素のそれぞれについて、各種粒子分散セラミックス焼結体を作製し、その特性を評価した。その結果、ビッカース硬度が高くかつ耐欠損性(=破壊靭性値、KIC)に優れたセラミックス焼結体が優れた特性を有する関係を見い出した。特に、Cr2N粒子を分散した窒化珪素を焼結した粒子分散窒化珪素質焼結体、ならびにTi-Zr-B固溶体粒子、Ti-Hf-B固溶体粒子の1種または2種を分散した炭化珪素を焼結した粒子分散炭化珪素質焼結体を成形加工したシフトサイドガイドロールは、従来の溶射ロールに比べて、耐摩耗性を高めつつ、かつチッピング、剥離や割れ等の耐欠損性を著しく改善できる。図2に本発明による粒子分散窒化珪素質焼結体を帯状リングに成形加工し、この帯状リングを嵌合させたシフトサイドガイドロール3を酸洗ラインの鋼板2の幅方向位置決め用として組み込んだ設備の配置図を示した。
【0012】
以下、粒子分散窒化珪素質焼結体ならびに粒子分散炭化珪素質焼結体に関し、個別に詳細な説明を行う。
窒化珪素セラミックス単体では、破壊靭性に劣るため、窒化珪素に以下の基準で選ばれた粒子を分散させることが有効である。窒化珪素とCr2N粒子との熱膨張差やヤング率の相違等により、分散したCr2N粒子の近傍に残留応力が発生し、焼結体の破壊の際の破壊エネルギーを分散させることに伴い、靭性を著しく向上させ、かつ耐摩耗性も向上させる作用を発現することが可能になった。中でも、Cr2N粒子の平均粒径は0.5〜10μmであることが望ましい。より好ましくは3〜7μmである。平均粒径が0.5μmより小さいと、靭性への寄与が得られ難く、一方、10μmより大きいと、ビッカース硬さや破壊靭性値の低下を招く。加えて、Cr2N粒子の体積分率は1〜8%であることが望ましい。体積分率が1%より少ないと、硬さ、靭性の向上に対する寄与が得られ難く、一方、8%を越えると、粒子分散による残留応力が過大となり、破壊靭性の低下と共に耐欠損性が低下する。さらに、前記Cr2N粒子分散窒化珪素質焼結体の相対密度は理論密度に対して99%以上であることが望ましい。相対密度が99%未満では、粒子分散による焼結体への残留応力の付与が不充分になり、破壊靭性の向上効果が見られない。ロール全体をセラミックス化する場合に加え、嵌合リングを用いる場合のリング肉厚は本材料系では10mm以上が好ましく、費用面からリングの単価を軽減するには厚さ10mm以上、20mm以下が好適である。
【0013】
本発明の位置決め用シフトサイドガイドロールは、窒化珪素粉末にCr2N粒子と必要に応じて焼結助剤を所定量添加、混合した後、焼結したものを成形加工することにより製造でき、その製造方法を限定するものではない。詳しくは、窒化珪素は共有結合性の強い物質であり、単独では焼結が困難であることが多いため、緻密化するために焼結助剤を添加することが望ましい。焼結助剤としては、希土類酸化物、窒化アルミニウム、酸化アルミニウム、酸化マグネシウム、等を用いることができる。希土類酸化物としては酸化イットリウム、酸化イッテルビウム、酸化エルビウム、等から選ぶことが出来る。焼結助剤の添加量は、窒化珪素粉末の純度や粒径によって変動する必要があるが、窒化珪素100質量部に対し、酸化イットリウムが3〜8質量部、酸化マグネシウムが2〜5質量部などが好ましい。焼結方法についても、特に限定するものではなく、例えば無加圧焼結法、ガス圧焼結法、熱間静水圧プレス焼結法、ホットプレス焼結法、等の各種焼結法を用いることができ、さらにこれらの焼結法を複数組み合せても良い。無加圧焼結法は、真空中又は不活性ガス流通中で行なうと緻密な焼結体が得られ易い。
【0014】
また、シフトサイドガイドロールを製造する場合には、十分な緻密化を図るために、無加圧焼結後に、さらに不活性ガス雰囲気中での熱間静水圧プレス焼結を行うことが好ましい。焼結条件としては、焼結温度が1550〜1700℃、保持時間が2時間以上であることが望ましい。1550℃未満では、緻密な焼結体が得られず、固溶体粒子近傍に残留応力を十分に発生させることが困難となり、高靭性の焼結体とすることができない。一方、1700℃を越える高温では、マトリックスの窒化珪素が昇華、分解するため、焼結体が得られない。また、保持時間が2時間未満では、緻密化が十分に起こらないため、焼結体の粒子分散の効果が得られない。次に、粒子分散炭化珪素質焼結体について説明する。
【0015】
炭化珪素セラミックス単体では、ビッカース硬度は比較的高いが破壊靭性に劣るため炭化珪素に以下の基準で選ばれた粒子を分散させることが有効である。炭化珪素とTi-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子との熱膨張差やヤング率の相違等により、分散したTi-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子の近傍に残留応力が発生し、焼結体の破壊の際の破壊エネルギーを分散させることができ、破壊靭性値を著しく向上させ、かつ耐摩耗性も向上させる作用を発現することが可能になる。このTi-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子は、硬質かつ耐酸化性のあるhcp構造の高融点化合物であり、焼結後に炭化珪素質焼結体中に分散粒子として残留し、焼結体全体のビッカース硬度や破壊靭性値を向上させる作用を有する。ロール全体をセラミックス化する場合に加え、嵌合リングを用いる場合のリング肉厚は本材料系では15mm以上が好ましく、費用面からリングの単価を軽減するには厚さ15mm以上25mm以下が好適である。
【0016】
Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子の組成は、それぞれTi1-xZrxB2、Ti1-xHfxB2で表され、xの範囲は0.02〜0.25が好ましく、より好ましくは0.02〜0.05である。TiB2にZrB2やHfB2を固溶させると、TiB2単体に比べ、硬度や破壊靭性値が上昇する。しかしながら、xが0.02より小さい場合には、Zr、HfのTiB2への固溶効果が乏しくなり、十分な高硬度化が図れない恐れがあり、一方、xが0.25を越える場合には、マトリックスの炭化珪素との熱膨張係数が掛け離れてしまうため、焼結時に緻密化し難くなり、相対密度の低い焼結体となり易く、破壊靭性値も低下する恐れが高くなる。また、前記固溶体粒子の平均粒径は1〜10μmであることが望ましい。より好ましくは3〜5μmである。平均粒径が1μmより小さいと、靭性への寄与が得られ難く、一方、10μmより大きいと、硬さや破壊靭性値の低下を招く。前記Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子の体積分率は20〜70%であることが望ましい。体積分率が20%より少ないと、硬さ、靭性の向上に対する寄与が得られ難く、一方、70%を越えると、粒子分散による残留応力が過大となり、破壊靭性の低下と共に耐欠損性が低下する。さらに、前記Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子分散炭化珪素質焼結体の相対密度は理論密度に対して99.5%以上であることが望ましい。相対密度が99.5%未満では、粒子分散による焼結体への残留応力の付与が不充分になり、靭性向上の効果が見られない。
【0017】
本発明の位置決め用シフトサイドガイドロールは、炭化珪素粉末にTi-Zr-B固溶体粒子、Ti-Hf-B固溶体粒子の1種または2種と必要に応じて焼結助剤を所定量添加、混合した後、焼結したものを成形加工することにより製造でき、製造方法を限定するものではない。より詳しくは、Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子は、複合硼化物粒子として添加する以外に、例えば、TiB2とZrB2、ZrC、HfB2、HfCの所定量を炭化珪素に混合し、焼結時の反応により複合硼化物を形成しても良い。また、炭化珪素は共有結合性の強い物質であり、単独では焼結が困難であることが多いため、緻密化するために焼結助剤を添加することが望ましい。
【0018】
焼結助剤としては、炭化硼素、金属硼素、カーボンブラックや有機質炭素等の各種炭素材料、窒化アルミニウム、酸化アルミニウム、希土類酸化物、等を用いることができる。焼結助剤の添加量は、炭化珪素粉末の純度や粒径によって変動する必要があるが、炭化珪素100質量部に対し炭化硼素が0.1〜2.0質量部(外換算)、炭素が0.5〜2.5質量部(外換算)などが好ましい。
【0019】
同様に、焼結方法も限定するものではなく、例えば無加圧焼結法、ガス圧焼結法、熱間静水圧プレス焼結法、ホットプレス焼結法、等の各種焼結法を用いることができ、さらにこれらの焼結法を複数組み合せても良い。無加圧焼結法は、真空中又は不活性ガス流通中で行うと緻密な焼結体が得られ易い。また、大型厚肉形状のシフトサイドガイドロールを製造する場合には、十分な緻密化を図るために、無加圧焼結後に、さらに不活性ガス雰囲気中での熱間静水圧プレス焼結を行うことが好ましい。焼結条件としては、焼結温度が1850〜2200℃、保持時間が3時間以上であることが望ましい。1850℃未満では、緻密な焼結体が得られず、固溶体粒子近傍に残留応力を十分に発生させることが困難となり、高靭性の焼結体とすることができない。一方、2200℃を越える高温では、マトリックスの炭化珪素が昇華、分解するため、焼結体が得られない。また、保持時間が3時間未満では、焼結反応による複合硼化物粒子生成が十分には起こらないため、焼結体の粒子分散の効果が得られない。
【0020】
【実施例】
本発明の実施例を比較例と共に説明する。
(実施例1〜5)
窒化珪素(Si3N4)粉末(α型、純度99.7%、平均粒径0.3μm)に窒化クロム(Cr2N)粉末(表1に示した平均粒径を使用)、窒化チタン(TiN)粉末(平均粒径3μm)、酸化イットリウム(Y2O3)粉末(平均粒径1.5μm)、酸化イッテルビウム(Yb2O5)粉末(平均粒径1μm)、酸化エルビウム(Er2O3)粉末(平均粒径1μm)、酸化マグネシウム(MgO)粉末(平均粒径0.3μm)を表1に示す所定量(質量%)添加し、分散媒として精製水またはアセトンを用い、炭化珪素セラミックスを内貼りしたボールミルで48時間混練した。精製水またはアセトンの添加量は、セラミックス全粉末原料100gに対し120gとした。
【0021】
次いで、得られた混合粉末を成形後、焼結した。成形条件としては冷間静水圧による加圧150MPaとし、φ220mm(内径φ115mm)×長さ220mmを2個、φ220mm(内径φ135mm)×長さ80mmを2個の各円筒を成形した。これを素地加工し、φ205mm(内径φ155mm)×長さ210mmを2個、φ205mm(内径φ175mm)×長さ70mmを2個の計4個の成形体を得た。焼結条件としては、N2ガス流通中にて、表1中に示す温度で4時間保持の無加圧焼結後、同じく表1中に示す温度、高圧N2ガス雰囲気中にて6時間保持の熱間静水圧プレス(HIP)焼結を行った。得られた焼結体から、それぞれφ150mm(内径φ91mm)×長さ160mmを2個、φ150mm(内径φ120mm)×長さ55mmを2個の焼結体加工を行い、酸洗ラインでの実機通材耐久試験に供した。後者に関しては、鋼材(SNCM439)の同心円筒を上下方向に2分割し、帯状リングを有機系接着剤を用いて接着・固定した後に、耐久試験を行った。
(実施例6〜10)
炭化珪素(SiC)粉末(α型、純度99%、平均粒径0.7μm)に硼化チタン(TiB2)粉末(平均粒径3.2μm)、硼化ジルコニウム(ZrB2)粉末(平均粒径3μm)、炭化ジルコニウム(ZrC)粉末(平均粒径2.5μm)、硼化ハフニウム(HfB2)粉末(平均粒径4μm)、炭化ハフニウム(HfC)粉末(平均粒径4.5μm)、炭化硼素(B4C)粉末(平均粒径0.6μm)、及び炭素(C)粉末(平均粒径0.02μm)を表2に示す所定量(質量%)添加し、分散媒として精製水またはアセトンを用い、炭化珪素セラミックスを内貼りしたボールミルで48時間混練した。精製水またはアセトンの添加量は、セラミックス全粉末原料100gに対し80gとした。
【0022】
次いで、得られた混合粉末を成形後、焼結した。成形条件としては冷間静水圧による加圧150MPaとし、φ200mm(内径φ105mm)×長さ210mmを2個、φ200mm(内径φ105mm)×長さ360mmを2個の長円筒を成形した。これを素地加工し、φ185mm(内径φ110mm)×長さ200mmを2個、φ185mm(内径φ105mm)×長さ330mmを2個の計4個の成形体を得た。焼結条件としては、Arガス流通中にて、表2に示す温度で12時間保持の無加圧焼結後、同じく表2中に示す温度、高圧Arガス雰囲気中にて6時間保持の熱間静水圧プレス(HIP)焼結を行った。得られた焼結体から、それぞれφ150mm(内径φ91mm)×長さ160mmを2個、φ150mm(内径φ91mm)×長さ270mmを2個の焼結体加工を行い、酸洗ラインでの実機通材耐久試験に供した。
【0023】
一方、得られた上記各実施例の焼結体から各種形状の試験片を切り出し、機械的特性を評価した。硬さは、押込荷重98Nにてビッカース硬さとして測定した。靭性についてはJIS R1607のSEPB法により室温にて破壊靭性値KICを測定した。焼結体密度は、アルキメデス法により相対密度として測定した。Cr2N粒子、ならびにTi-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子の粒径および体積分率は、焼結体の鏡面研磨面を撮影した光学顕微鏡像(拡大率500倍)より30個以上の粒子径および撮影面中の粒子面積分率として測定し、その平均値として表した。 また、Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子を分散した炭化珪素を焼結した粒子分散炭化珪素質焼結体については、X線回折法を用いて、混合前の原料粉末段階でのTiB2、ZrC、ZrB2、HfC及びHfB2各粉末のX線回折ピークをそれぞれ測定し、混合・成形し焼結後の焼結体のX線回折ピークと照合し、TiB2中にZrもしくはHfが固溶していることを確認した。
【0024】
得られた各焼結体の諸特性をCr2N粒子、Ti-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子の粒径、体積分率、x値、焼結体密度と共に表3、表4に示す。オンライン通板試験としては、常温大気中、板厚3.0mm、通板速度は700m/分の条件にて行った。2ヶ月間の鋼板の通材後、各ロールに発生した摩耗痕跡の深さhを投影型顕微鏡にて測定し、各形状(φ150mm(内径φ91mm)×L160mm、φ150mm(内径φ91mm)×L270mm)の平均値を求めた。また、摩耗痕跡周囲の損傷有無、チッピング深さ、および割れ深さを蛍光探傷法および断面研磨面の光学顕微鏡観察により評価した。
(比較例11〜19)
比較例11〜13は、分散粒子をCr2NからTiNに置き換えた場合の比較例である。比較例14は、粒子分散を行っていない窒化珪素焼結体である。これらを併せて表1に示す。比較例15〜17は、実施例6〜10と同一原料を用い、同じく精製水またはアセトンで調製したが、それぞれTiB2のみを添加した場合(比較例15)、ZrB2のみを添加した場合(比較例16)、HfB2のみを添加した場合(比較例17)の各比較例である。比較例18は、粒子分散を行っていない炭化珪素焼結体であり、これらを併せて表2に示す。比較例19は、従来の金属製ロールで、摩耗試験結果のみを表3に併記した。これら全ての比較例の材料も実施例1〜10と同様の条件で通材試験を行い、各形状の平均値を示した。
【0025】
表3、表4に示すように、本発明の実施例によるものは、摩耗痕跡深さが250μm以下と非常に少なく、かつ摩耗痕跡周囲には割れ・剥離・チッピング等の欠損が何れの場合も認められず、耐摩耗性、耐欠損性共に優れるが、比較例の各シフトサイドガイドロールは、本発明の実施例に比べて、使用不能になるまでの摩耗痕跡深さ450μm以上と大きく、その上、ヒビやクラック等の欠損も発生する場合があり、耐摩耗性、耐欠損性が不充分であることが確認された。
【0026】
【表1】

Figure 0004690553
【0027】
【表2】
Figure 0004690553
【0028】
【表3】
Figure 0004690553
【0029】
【表4】
Figure 0004690553
【0030】
【発明の効果】
以上述べたように、本発明の窒化クロム(Cr2N)粒子を分散した窒化珪素を焼結した粒子分散窒化珪素質焼結体、またはTi-Zr-B固溶体粒子及び/又はTi-Hf-B固溶体粒子を分散した炭化珪素を焼結した粒子分散炭化珪素質焼結体を成形加工してなるシフトサイドガイドロールは、ビッカース硬度や破壊靭性値に代表される機械的安定性に優れ、長期耐久性を有する。本発明のシフトサイドガイドロールを使用すれば、鉄鋼製造プロセスの酸洗ライン工程等におけるシフトサイドガイドロールの長寿命化による資材費圧縮と安定操業による生産性向上に伴う製造コスト低減に寄与すること大である。
【図面の簡単な説明】
【図1】鋼板の幅方向の位置決め用シフトサイドガイドロール配置概略図。
【図2】本発明の実施形態の一例を示すシフトサイドガイドロール配置概略図。
【符号の説明】
1…シフトサイドガイドロール
2…鋼板
3…嵌合させたセラミックス製リングを用いたシフトサイドガイドロール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shift side guide roll used for widthwise positioning during steel sheet conveyance and winding.
[0002]
[Prior art]
In the steel manufacturing facility, as shown in FIG. 1, the steel plate 2 is led out from the coil by the pickling line (entry side), immersed in acid, and wound around the coil again (exit side) in the width direction of the steel plate 2. 2 to 6 rolls / set used for positioning are incorporated in the pickling line with a roll 1 called a shift side guide roll. Conventionally, rolls in which WC-Ni-Cr thermal spraying is applied to hardened steel (SUJ2, SNCM439, etc.) have been used. This equipment is equipped with dozens of large rolls of φ150mm × L160mm or φ150mm × L270mm. When a steel plate with a thickness of 1 to 6 mm and a maximum thickness of 3 mm passes at a maximum speed of 700 m / min (= 42 km / h), the width of the steel plate end surface slides on the roll while the width is shifted by this shift side guide roll. Will be positioned in the direction.
[0003]
However, since the above equipment has the structure as described above, a pressing load is applied only on substantially the same circumference line, regardless of whether the roll is 160 mm or 270 mm in length, and continues to receive irregular vibrations. The use environment is extremely severe. For this reason, as the material of this roll, since the metal is inferior in durability and the replacement frequency is high, application of ceramics having high hardness and excellent wear resistance has been studied.
[0004]
Until now, silicon nitride-based sintered bodies have excellent properties in high temperature strength and hardness, but are inferior in fracture toughness and wear resistance and have not been practical materials. Therefore, in order to increase the toughness of the silicon nitride sintered body, research and development of a particle-dispersed silicon nitride sintered body in which various particles and whiskers are dispersed has been underway. However, there are few material systems that can maintain high hardness and wear resistance, impeding practical use. Similarly, the silicon carbide based sintered body has excellent properties in high temperature strength and hardness in the air atmosphere, but is inferior in fracture toughness and wear resistance, and is hardly a practical material.
[0005]
Therefore, in order to increase the toughness of the silicon carbide sintered body, research and development of a particle-dispersed silicon carbide sintered body in which various particles and whiskers are dispersed has been underway. However, there are few material systems that can maintain high hardness and wear resistance, impeding practical use.
[0006]
[Problems to be solved by the invention]
As described above, in an actual roll use environment, it is necessary to have excellent mechanical stability such as mechanical durability against vibration during height fluctuation when passing through the plate, and fracture resistance during handling, etc. An object of the present invention is to provide a shift side guide roll for positioning the pickling line in the width direction, which has a material that is extremely excellent in any required characteristics.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have conducted intensive studies on dispersed particles in silicon nitride and silicon carbide ceramic sintered bodies. As a result, when specific dispersed particles are used, a shift for positioning in the width direction is performed. A sintered body having excellent characteristics can be obtained when a ring made of a side guide roll or silicon nitride and silicon carbide ceramic sintered body is fitted to at least a sliding portion of the metal shift side guide roll with a steel plate. The headline and the present invention have been completed.
[0008]
That is, the present invention
(1) A particle-dispersed silicon nitride sintered body obtained by sintering silicon nitride in which chromium nitride (Cr2N) particles are dispersed is formed into a ring shape, and the ring is slid with at least a metal plate of a shift side guide roll made of metal. A fitting ring for a shift side guide roll having a thickness of 10 mm or more and 20 mm or less, wherein the fitting ring is fitted to a moving part.
(2) The fitting ring for a shift side guide roll according to claim 1, wherein the chromium nitride (Cr2N) particles have an average particle size of 0.5 to 10 µm.
(3) The fitting ring for shift side guide rolls according to claim 1, wherein the volume fraction of the chromium nitride (Cr2N) particles is 1 to 8%.
(4) The fitting ring for shift side guide rolls according to claim 1, wherein the relative density of the particle-dispersed silicon nitride sintered body is 99% or more.
(5) A particle-dispersed silicon carbide sintered body obtained by sintering silicon carbide in which one or two of Ti-Zr-B solid solution particles and Ti-Hf-B solid solution particles are dispersed is molded into a ring shape, A fitting ring for a shift side guide roll having a wall thickness of 10 mm or more and 20 mm or less, wherein the ring is fitted to at least a sliding portion of the metal shift side guide roll with a steel plate.
(6) The fitting ring for a shift side guide roll according to claim 5, wherein the composition of the Ti-Zr-B solid solution particles is Ti1-xZrxB2 (0.02 ≦ x ≦ 0.25).
(7) The fitting ring for a shift side guide roll according to claim 5, wherein the composition of the Ti-Hf-B solid solution particles is Ti1-xHfxB2 (0.02 ≦ x ≦ 0.25).
(8) The fitting ring for shift side guide rolls according to claim 5 , wherein the average particle diameter of the solid solution particles is 1 to 10 μm.
(9) The fitting ring for a shift side guide roll according to claim 5 , wherein the volume fraction of the solid solution particles is 20 to 70%.
(10) The fitting ring for shift side guide rolls according to claim 5, wherein the particle-dispersed silicon carbide sintered body has a relative density of 99.5% or more.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
As a result of earnest analysis of the wear situation of shift side guide rolls in which WC-Ni-Cr is sprayed on the quenching metal for positioning in the width direction of the steel plate of the pickling line that has been used conventionally, It has been found that the surface layer easily wears and wears when the material passes at a high speed when the material is inferior in hardness. It was also found that many rough skins were observed around the worn part. These wear and roughness were particularly noticeable when the shift side guide roll had a low hardness. Therefore, in order to use the positioning roll in the width direction of the pickling line stably for a long period of time, it is necessary to simultaneously improve the wear resistance and fracture resistance. It was found that the rolls were replaced with materials. However, when manufacturing the whole roll with ceramics, the manufacturing cost becomes high, so partial replacement was also studied.
[0010]
As a result, the sliding surface with the steel plate varies depending on the height of the vertical motion of the steel plate, but usually within the range of vertical movement up to + 30mm and down to -10mm at the plate speed up to 700m / min. It has been confirmed. Therefore, it is preferable to have a belt height of about 50 mm when the safety factor is expected to be about 20% and the belt-like ring is fitted. In addition, the steel roll base that fits the ceramic ring is preferably a steel type such as SUJ or SNCM439 that can be easily hardened by quenching, and the ceramic ring has a thickness that does not interfere with strength when sliding. It is suitable to perform circular grinding so that there is no step at the boundary with the metal roll base after the fitting, bonding and fixing.
[0011]
In order to improve these characteristics at the same time, various particle-dispersed ceramic sintered bodies were produced for each of silicon nitride and silicon carbide, and the characteristics were evaluated. As a result, it was found that a ceramic sintered body having high Vickers hardness and excellent fracture resistance (= fracture toughness value, K IC ) has excellent characteristics. In particular, a particle-dispersed silicon nitride sintered body obtained by sintering silicon nitride in which Cr 2 N particles are dispersed, and a carbonization in which one or two of Ti-Zr-B solid solution particles and Ti-Hf-B solid solution particles are dispersed. Shift side guide rolls made by molding silicon-dispersed silicon carbide sintered bodies with improved silicon wear resistance and chipping, peeling and cracking resistance compared to conventional thermal spray rolls. It can be remarkably improved. In FIG. 2, the particle-dispersed silicon nitride sintered body according to the present invention is formed into a band-shaped ring, and a shift side guide roll 3 fitted with the band-shaped ring is incorporated for positioning in the width direction of the steel plate 2 in the pickling line. The layout of the equipment is shown.
[0012]
Hereinafter, the particle-dispersed silicon nitride sintered body and the particle-dispersed silicon carbide sintered body will be individually described in detail.
Since silicon nitride ceramics alone is inferior in fracture toughness, it is effective to disperse particles selected according to the following criteria in silicon nitride. Residual stress is generated in the vicinity of dispersed Cr 2 N particles due to differences in thermal expansion and Young's modulus between silicon nitride and Cr 2 N particles. As a result, it has become possible to significantly improve toughness and improve wear resistance. Among these, the average particle size of the Cr 2 N particles is preferably 0.5 to 10 μm. More preferably, it is 3-7 micrometers. When the average particle size is less than 0.5 μm, it is difficult to obtain a contribution to toughness, while when it is greater than 10 μm, the Vickers hardness and fracture toughness value are lowered. In addition, the volume fraction of Cr 2 N particles is desirably 1 to 8%. If the volume fraction is less than 1%, it is difficult to contribute to the improvement of hardness and toughness. On the other hand, if it exceeds 8%, the residual stress due to particle dispersion becomes excessive, and the fracture resistance decreases as the fracture toughness decreases. To do. Furthermore, the relative density of the Cr 2 N particle-dispersed silicon nitride sintered body is desirably 99% or more with respect to the theoretical density. When the relative density is less than 99%, the residual stress is not sufficiently applied to the sintered body due to particle dispersion, and the effect of improving fracture toughness is not observed. In addition to the case where the entire roll is made into ceramic, the ring thickness when using a fitting ring is preferably 10 mm or more in this material system, and the thickness is preferably 10 mm or more and 20 mm or less to reduce the unit price of the ring from the cost aspect. It is.
[0013]
The shift side guide roll for positioning of the present invention can be produced by adding a predetermined amount of Cr 2 N particles and, if necessary, a sintering aid to the silicon nitride powder, mixing, and then molding the sintered product, The manufacturing method is not limited. Specifically, silicon nitride is a substance having a strong covalent bond, and it is often difficult to sinter alone. Therefore, it is desirable to add a sintering aid for densification. As the sintering aid, rare earth oxide, aluminum nitride, aluminum oxide, magnesium oxide, or the like can be used. The rare earth oxide can be selected from yttrium oxide, ytterbium oxide, erbium oxide, and the like. The addition amount of the sintering aid needs to vary depending on the purity and particle size of the silicon nitride powder, but 3 to 8 parts by mass of yttrium oxide and 2 to 5 parts by mass of magnesium oxide with respect to 100 parts by mass of silicon nitride. Etc. are preferable. The sintering method is not particularly limited, and various sintering methods such as a pressureless sintering method, a gas pressure sintering method, a hot isostatic pressing method, a hot press sintering method, and the like are used. Further, a plurality of these sintering methods may be combined. When the pressureless sintering method is performed in a vacuum or in an inert gas flow, a dense sintered body is easily obtained.
[0014]
Moreover, when manufacturing a shift side guide roll, it is preferable to perform hot isostatic pressing sintering in an inert gas atmosphere after pressureless sintering in order to achieve sufficient densification. As sintering conditions, it is desirable that the sintering temperature is 1550 to 1700 ° C. and the holding time is 2 hours or more. If the temperature is less than 1550 ° C., a dense sintered body cannot be obtained, and it becomes difficult to generate sufficient residual stress in the vicinity of the solid solution particles, so that a high toughness sintered body cannot be obtained. On the other hand, at a high temperature exceeding 1700 ° C., the silicon nitride in the matrix sublimates and decomposes, so that a sintered body cannot be obtained. Further, if the holding time is less than 2 hours, the densification does not occur sufficiently, so that the effect of dispersing the particles of the sintered body cannot be obtained. Next, the particle-dispersed silicon carbide sintered body will be described.
[0015]
Since silicon carbide ceramics have relatively high Vickers hardness but poor fracture toughness, it is effective to disperse particles selected on the basis of the following criteria in silicon carbide. Dispersed Ti-Zr-B solid solution particles and / or Ti-Hf-B due to differences in thermal expansion and Young's modulus between silicon carbide and Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles Residual stress is generated in the vicinity of solid solution particles, which can disperse the fracture energy at the time of fracture of the sintered body, can significantly improve the fracture toughness and improve the wear resistance. become. This Ti-Zr-B solid solution particle and / or Ti-Hf-B solid solution particle is a high melting point compound having a hard and oxidation-resistant hcp structure and is dispersed as a dispersed particle in a silicon carbide sintered body after sintering. It remains and has the effect of improving the Vickers hardness and fracture toughness value of the entire sintered body. In addition to the case where the entire roll is made of ceramic, the ring thickness when using a fitting ring is preferably 15 mm or more in this material system. From the cost aspect, a thickness of 15 mm or more and 25 mm or less is suitable for reducing the unit price of the ring. is there.
[0016]
The composition of Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles is represented by Ti 1-x Zr x B 2 and Ti 1-x Hf x B 2 respectively , and the range of x is 0.02 to 0.25. Is preferable, and more preferably 0.02 to 0.05. When the the TiB 2 solid solution of ZrB 2 and HfB 2, compared with the TiB 2 alone, hardness and fracture toughness value increases. However, if x is smaller than 0.02, the solid solution effect of Zr and Hf in TiB 2 may be poor, and sufficient hardness may not be achieved. Since the thermal expansion coefficient of silicon carbide is far from that of silicon carbide, it becomes difficult to be densified during sintering, and a sintered body having a low relative density is likely to be obtained, and the fracture toughness value is likely to be lowered. The average particle size of the solid solution particles is preferably 1 to 10 μm. More preferably, it is 3-5 micrometers. If the average particle size is less than 1 μm, it is difficult to obtain a contribution to toughness, while if it is greater than 10 μm, the hardness and fracture toughness values are reduced. The volume fraction of the Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles is preferably 20 to 70%. If the volume fraction is less than 20%, it is difficult to contribute to the improvement of hardness and toughness. On the other hand, if it exceeds 70%, the residual stress due to particle dispersion becomes excessive, and the fracture resistance decreases as the fracture toughness decreases. To do. Furthermore, the relative density of the Ti—Zr—B solid solution particles and / or the Ti—Hf—B solid solution particle-dispersed silicon carbide sintered body is preferably 99.5% or more with respect to the theoretical density. When the relative density is less than 99.5%, the residual stress is not sufficiently applied to the sintered body due to particle dispersion, and the effect of improving toughness is not observed.
[0017]
The shift side guide roll for positioning according to the present invention includes a predetermined amount of one or two types of Ti-Zr-B solid solution particles and Ti-Hf-B solid solution particles and, if necessary, a sintering aid added to silicon carbide powder. After mixing, the sintered product can be manufactured by molding, and the manufacturing method is not limited. More specifically, Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles are added as composite boride particles, for example, a predetermined amount of TiB 2 and ZrB 2 , ZrC 2 , ZrC, HfB 2 , HfC May be mixed with silicon carbide to form a composite boride by a reaction during sintering. In addition, silicon carbide is a substance having a strong covalent bond and is often difficult to sinter alone. Therefore, it is desirable to add a sintering aid for densification.
[0018]
As the sintering aid, boron carbide, metal boron, various carbon materials such as carbon black and organic carbon, aluminum nitride, aluminum oxide, rare earth oxide, and the like can be used. The addition amount of the sintering aid needs to vary depending on the purity and particle size of the silicon carbide powder, but the boron carbide is 0.1 to 2.0 parts by mass (external conversion) and the carbon is 0.5 to 2.5 with respect to 100 parts by mass of silicon carbide. A mass part (external conversion) etc. are preferable.
[0019]
Similarly, the sintering method is not limited. For example, various sintering methods such as a pressureless sintering method, a gas pressure sintering method, a hot isostatic pressing method, and a hot press sintering method are used. Further, a plurality of these sintering methods may be combined. When the pressureless sintering method is performed in a vacuum or in an inert gas flow, a dense sintered body is easily obtained. In addition, when manufacturing a large, thick-walled shift side guide roll, hot isostatic pressing in an inert gas atmosphere is further performed after pressureless sintering in order to achieve sufficient densification. Preferably it is done. As sintering conditions, it is desirable that the sintering temperature is 1850 to 2200 ° C. and the holding time is 3 hours or more. If it is less than 1850 ° C., a dense sintered body cannot be obtained, and it becomes difficult to generate sufficient residual stress in the vicinity of the solid solution particles, so that a high toughness sintered body cannot be obtained. On the other hand, at a high temperature exceeding 2200 ° C., the silicon carbide in the matrix sublimates and decomposes, so that a sintered body cannot be obtained. In addition, when the holding time is less than 3 hours, composite boride particles are not sufficiently generated by the sintering reaction, so that the effect of dispersing the particles of the sintered body cannot be obtained.
[0020]
【Example】
Examples of the present invention will be described together with comparative examples.
(Examples 1 to 5)
Silicon nitride (Si 3 N 4 ) powder (α type, purity 99.7%, average particle size 0.3 μm) and chromium nitride (Cr 2 N) powder (using the average particle size shown in Table 1), titanium nitride (TiN) Powder (average particle size 3 μm), yttrium oxide (Y 2 O 3 ) powder (average particle size 1.5 μm), ytterbium oxide (Yb 2 O 5 ) powder (average particle size 1 μm), erbium oxide (Er 2 O 3 ) powder (Average particle size 1 μm), magnesium oxide (MgO) powder (average particle size 0.3 μm) is added in a predetermined amount (mass%) shown in Table 1, and purified water or acetone is used as a dispersion medium, and silicon carbide ceramics is applied on the inside. Kneaded for 48 hours in a ball mill. The amount of purified water or acetone added was 120 g with respect to 100 g of all ceramic powder raw materials.
[0021]
Next, the obtained mixed powder was molded and then sintered. The molding conditions were a pressure of 150 MPa by cold isostatic pressure, and two cylinders each having a diameter of 220 mm (inner diameter: 115 mm) × 220 mm in length and two of 220 mm (inner diameter: 135 mm) × 80 mm in length were formed. This was processed to obtain a total of four compacts, two pieces of φ205 mm (inner diameter φ155 mm) × length 210 mm and two pieces of φ205 mm (inner diameter φ175 mm) × length 70 mm. Sintering conditions were as follows: pressureless sintering for 4 hours at the temperature shown in Table 1 during N 2 gas circulation, and 6 hours in the same high temperature N 2 gas atmosphere as shown in Table 1 Holding hot isostatic pressing (HIP) sintering was performed. From the obtained sintered bodies, processing each of the two sintered bodies of φ150mm (inner diameter φ91mm) x length 160mm, φ150mm (inner diameter φ120mm) x length 55mm, and the actual machine through the pickling line It used for the endurance test. Regarding the latter, a concentric cylinder of steel (SNCM439) was divided into two in the vertical direction, and a band-like ring was bonded and fixed using an organic adhesive, and then a durability test was performed.
(Examples 6 to 10)
Silicon carbide (SiC) powder (α type, purity 99%, average particle size 0.7 μm), titanium boride (TiB 2 ) powder (average particle size 3.2 μm), zirconium boride (ZrB 2 ) powder (average particle size 3 μm) ), Zirconium carbide (ZrC) powder (average particle size 2.5 μm), hafnium boride (HfB 2 ) powder (average particle size 4 μm), hafnium carbide (HfC) powder (average particle size 4.5 μm), boron carbide (B 4 C) Powder (average particle size 0.6 μm) and carbon (C) powder (average particle size 0.02 μm) are added in predetermined amounts (mass%) shown in Table 2, and purified water or acetone is used as a dispersion medium, silicon carbide The mixture was kneaded for 48 hours in a ball mill with ceramics attached inside. The amount of purified water or acetone added was 80 g with respect to 100 g of all ceramic powder raw materials.
[0022]
Next, the obtained mixed powder was molded and then sintered. The molding conditions were a pressure of 150 MPa by cold isostatic pressure, and two long cylinders of φ200 mm (inner diameter φ105 mm) × 210 mm length and φ200 mm (inner diameter φ105 mm) × 360 mm length were formed. This was processed to obtain a total of four compacts of 2 pieces of φ185 mm (inner diameter φ110 mm) × length 200 mm and 2 pieces of φ185 mm (inner diameter φ105 mm) × length 330 mm. Sintering conditions were as follows: pressureless sintering for 12 hours at the temperature shown in Table 2 while circulating Ar gas, and heat for 6 hours in the high-pressure Ar gas atmosphere as shown in Table 2 Hot isostatic pressing (HIP) sintering was performed. From the obtained sintered bodies, processing each of the two sintered bodies of φ150mm (inner diameter φ91mm) x length 160mm and φ150mm (inner diameter φ91mm) x length 270mm, and the actual machine through the pickling line It used for the endurance test.
[0023]
On the other hand, test pieces of various shapes were cut out from the obtained sintered bodies of the respective Examples, and mechanical properties were evaluated. The hardness was measured as Vickers hardness at an indentation load of 98N. Regarding toughness, the fracture toughness value K IC was measured at room temperature by the SEPB method of JIS R1607. The sintered body density was measured as a relative density by the Archimedes method. The particle size and volume fraction of Cr 2 N particles, and Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles were measured with an optical microscope image (magnification of 500 times) of the mirror-polished surface of the sintered body. ), The particle size of 30 or more particles and the particle area fraction on the imaging surface were measured and expressed as the average value. In addition, for a particle-dispersed silicon carbide sintered body obtained by sintering silicon carbide in which Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles are dispersed, an X-ray diffraction method is used. Measure the X-ray diffraction peaks of TiB 2 , ZrC, ZrB 2 , HfC and HfB 2 powders at the raw material powder stage, check the X-ray diffraction peaks of the sintered body after mixing, forming and sintering, and TiB It was confirmed that Zr or Hf was dissolved in 2 .
[0024]
Various characteristics of each sintered body obtained are shown together with the particle size, volume fraction, x value, and sintered body density of Cr 2 N particles, Ti-Zr-B solid solution particles and / or Ti-Hf-B solid solution particles. 3 and shown in Table 4. The on-line plate test was conducted in a room temperature atmosphere at a plate thickness of 3.0 mm and a plate speed of 700 m / min. After passing the steel plate for 2 months, the depth h of the wear trace generated on each roll was measured with a projection microscope, and each shape (φ150 mm (inner diameter φ91 mm) × L160 mm, φ150 mm (inner diameter φ91 mm) × L270 mm) The average value was obtained. In addition, the presence or absence of damage around the wear trace, the chipping depth, and the crack depth were evaluated by fluorescent flaw detection and observation of the cross-section polished surface with an optical microscope.
(Comparative Examples 11-19)
Comparative Examples 11 to 13 are comparative examples when the dispersed particles are replaced from Cr 2 N to TiN. Comparative Example 14 is a silicon nitride sintered body that is not subjected to particle dispersion. These are also shown in Table 1. Comparative Examples 15 to 17 were prepared using the same raw materials as in Examples 6 to 10 and were similarly prepared with purified water or acetone, but each was added with TiB 2 only (Comparative Example 15), when only ZrB 2 was added ( Comparative examples 16) and Comparative examples in which only HfB 2 was added (Comparative Example 17). Comparative Example 18 is a silicon carbide sintered body not subjected to particle dispersion, and these are also shown in Table 2. Comparative Example 19 is a conventional metal roll, and only the wear test results are shown in Table 3. The materials of all these comparative examples were also subjected to a threading test under the same conditions as in Examples 1 to 10, and the average value of each shape was shown.
[0025]
As shown in Tables 3 and 4, according to the embodiment of the present invention, the wear trace depth is very small as 250 μm or less, and there are cracks, peeling, chipping, etc. around the wear trace. Although not recognized, both wear resistance and fracture resistance are excellent, but each shift side guide roll of the comparative example has a wear trace depth of 450 μm or more until it becomes unusable, compared to the examples of the present invention. In addition, cracks, cracks, and other defects may occur, and it was confirmed that the wear resistance and fracture resistance were insufficient.
[0026]
[Table 1]
Figure 0004690553
[0027]
[Table 2]
Figure 0004690553
[0028]
[Table 3]
Figure 0004690553
[0029]
[Table 4]
Figure 0004690553
[0030]
【The invention's effect】
As described above, the particle-dispersed silicon nitride sintered body obtained by sintering silicon nitride in which chromium nitride (Cr 2 N) particles are dispersed according to the present invention, or Ti-Zr-B solid solution particles and / or Ti-Hf- The shift side guide roll formed by molding a particle-dispersed silicon carbide sintered body obtained by sintering silicon carbide in which B solid solution particles are dispersed is excellent in mechanical stability typified by Vickers hardness and fracture toughness value. It has durability. If the shift side guide roll of the present invention is used, it contributes to the reduction of the manufacturing cost due to the material cost reduction by the long life of the shift side guide roll in the pickling line process of the steel manufacturing process and the productivity improvement by the stable operation. It ’s big.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a shift side guide roll arrangement for positioning in the width direction of a steel plate.
FIG. 2 is a schematic diagram of a shift side guide roll arrangement showing an example of an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shift side guide roll 2 ... Steel plate 3 ... Shift side guide roll using the ring made from ceramics fitted

Claims (10)

窒化クロム(Cr2N)粒子を分散した窒化珪素を焼結した粒子分散窒化珪素質焼結体をリング状に成形加工して、該リングを少なくとも金属製シフトサイドガイドロールの鋼板との摺動部分に嵌合させてなることを特徴とする肉厚10mm以上20mm以下のシフトサイドガイドロール用嵌合リングA particle-dispersed silicon nitride sintered body obtained by sintering silicon nitride in which chromium nitride (Cr2N) particles are dispersed is formed into a ring shape, and the ring is at least a sliding portion of the metal shift side guide roll with the steel plate. A fitting ring for a shift side guide roll having a wall thickness of 10 mm or more and 20 mm or less, characterized by being fitted . 前記窒化クロム(Cr2N)粒子の平均粒径が0.5〜10μmである請求項1記載シフトサイドガイドロール用嵌合リングThe fitting ring for a shift side guide roll according to claim 1 , wherein an average particle diameter of the chromium nitride (Cr2N) particles is 0.5 to 10 µm. 前記窒化クロム(Cr2N)粒子の体積分率が1〜8%である請求項1記載シフトサイドガイドロール用嵌合リングThe fitting ring for shift side guide rolls according to claim 1, wherein a volume fraction of the chromium nitride (Cr2N) particles is 1 to 8%. 前記粒子分散窒化珪素質焼結体の相対密度が99%以上である請求項1記載シフトサイドガイドロール用嵌合リングThe fitting ring for a shift side guide roll according to claim 1, wherein the relative density of the particle-dispersed silicon nitride sintered body is 99% or more. Ti-Zr-B固溶体粒子、Ti-Hf-B固溶体粒子の1種または2種を分散した炭化珪素を焼結した粒子分散炭化珪素質焼結体をリング状に成形加工して、該リングを少なくとも金属製シフトサイドガイドロールの鋼板との摺動部分に嵌合させてなることを特徴とする肉厚10mm以上20mm以下のシフトサイドガイドロール用嵌合リングA particle-dispersed silicon carbide sintered body obtained by sintering silicon carbide in which one or two of Ti-Zr-B solid solution particles and Ti-Hf-B solid solution particles are dispersed is formed into a ring shape, and the ring is formed. A fitting ring for a shift side guide roll having a wall thickness of 10 mm or more and 20 mm or less, wherein the fitting ring is fitted to at least a sliding portion of a metal shift side guide roll with a steel plate. 前記Ti-Zr-B固溶体粒子の組成が、Ti1-xZrxB2(0.02≦x≦0.25)である請求項5記載シフトサイドガイドロール用嵌合リングThe fitting ring for a shift side guide roll according to claim 5, wherein the composition of the Ti-Zr-B solid solution particles is Ti1-xZrxB2 (0.02≤x≤0.25). 前記Ti-Hf-B固溶体粒子の組成が、Ti1-xHfxB2(0.02≦x≦0.25)である請求項5記載シフトサイドガイドロール用嵌合リングThe fitting ring for a shift side guide roll according to claim 5, wherein the composition of the Ti-Hf-B solid solution particles is Ti1-xHfxB2 (0.02≤x≤0.25). 前記固溶体粒子の平均粒径が1〜10μmである請求項5記載シフトサイドガイドロール用嵌合リングThe fitting ring for shift side guide rolls according to claim 5 , wherein the solid solution particles have an average particle diameter of 1 to 10 μm. 前記固溶体粒子の体積分率が20〜70%である請求項5記載シフトサイドガイドロール用嵌合リングThe fitting ring for shift side guide rolls according to claim 5 , wherein the volume fraction of the solid solution particles is 20 to 70%. 前記粒子分散炭化珪素質焼結体の相対密度が99.5%以上である請求項5記載シフトサイドガイドロール用嵌合リングThe fitting ring for a shift side guide roll according to claim 5, wherein the particle-dispersed silicon carbide sintered body has a relative density of 99.5% or more.
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JPS63144816A (en) * 1986-12-08 1988-06-17 Kobe Steel Ltd Device for preventing meandering of plate stock in rolling mill
JPH06179005A (en) * 1992-12-10 1994-06-28 Ngk Insulators Ltd Combined construction roller
JPH09278529A (en) * 1996-04-04 1997-10-28 Nippon Steel Corp Wire rolling guide roller consisting of particle-dispersed silicon nitride-based baked body
JPH09278523A (en) * 1996-04-04 1997-10-28 Nippon Steel Corp Wire-mill guide roller made of sintered silicon carbide containing dispersed particle
JPH11239808A (en) * 1997-08-26 1999-09-07 Kawasaki Steel Corp Roll for rolling metallic sheet
JP2000280023A (en) * 1999-03-30 2000-10-10 Kawasaki Steel Corp Slit material roll up method and meandering prevention device
JP2000351671A (en) * 1999-06-11 2000-12-19 Nippon Steel Corp Particle-dispersed silicon carbide-based sintered product and guide roller which use the same and is used for rolling wire rod

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63144816A (en) * 1986-12-08 1988-06-17 Kobe Steel Ltd Device for preventing meandering of plate stock in rolling mill
JPH06179005A (en) * 1992-12-10 1994-06-28 Ngk Insulators Ltd Combined construction roller
JPH09278529A (en) * 1996-04-04 1997-10-28 Nippon Steel Corp Wire rolling guide roller consisting of particle-dispersed silicon nitride-based baked body
JPH09278523A (en) * 1996-04-04 1997-10-28 Nippon Steel Corp Wire-mill guide roller made of sintered silicon carbide containing dispersed particle
JPH11239808A (en) * 1997-08-26 1999-09-07 Kawasaki Steel Corp Roll for rolling metallic sheet
JP2000280023A (en) * 1999-03-30 2000-10-10 Kawasaki Steel Corp Slit material roll up method and meandering prevention device
JP2000351671A (en) * 1999-06-11 2000-12-19 Nippon Steel Corp Particle-dispersed silicon carbide-based sintered product and guide roller which use the same and is used for rolling wire rod

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