JP3816974B2 - Diffusion bonded metal carrier for catalyst having strong bonding strength and method for producing the same - Google Patents

Diffusion bonded metal carrier for catalyst having strong bonding strength and method for producing the same Download PDF

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JP3816974B2
JP3816974B2 JP25801495A JP25801495A JP3816974B2 JP 3816974 B2 JP3816974 B2 JP 3816974B2 JP 25801495 A JP25801495 A JP 25801495A JP 25801495 A JP25801495 A JP 25801495A JP 3816974 B2 JP3816974 B2 JP 3816974B2
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less
foil
stainless steel
metal carrier
honeycomb body
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JPH0999218A (en
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仁史 太田
幹雄 山中
忠幸 大谷
益啓 深谷
雅幸 糟谷
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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、各種内燃機関の排ガス浄化用等に好適な、強固な接合強度を有する拡散接合された触媒用メタル担体とその製造方法およびメタル担体用箔に関するものである。
【0002】
【従来の技術】
自動車、ボイラー、発電用など各種内燃機関の排ガス浄化用触媒の担体として、耐熱ステンレス鋼製の外筒に、同ステンレス鋼製のハニカム体を嵌入したメタル担体が、近年、多用されるようになってきた。ハニカム体は、厚さ50μm程度の帯状の平箔と、該平箔をコルゲート加工した帯状の波箔とを、重ねて渦巻状に巻回して形成されたものや、平板状の両箔を交互に積層して形成されたもの等が使用されている。
【0003】
ステンレス鋼としては、ハニカム体には、高温排ガス雰囲気での耐酸化性に優れたFe−20%Cr−5%Al等、Fe−Cr−Al系のフェライト系ステンレス鋼が多く採用され、外筒には、Al無添加のフェライト径ステンレス鋼も採用されている。また、添加元素により各種特性の改善が図られたもの、例えば、加工性向上等のためTiが添加されたもの、高温強度向上等のためNbが添加されたもの、耐酸化性をより向上させる等のため、La,Ce等の希土類元素が添加されたものが知られている。
【0004】
このようなメタル担体は、従来のセラミック製担体に比べて熱容量が小さいので、触媒が作用する温度に早く加熱され、エンジン始動初期の排ガス浄化能力が優れている。また、ハニカム体の壁が薄い金属箔からなるので、排気抵抗が小さく、エンジン出力の損失が少ない。さらに、温度の上下が激しい排ガス環境下においても、耐久性に優れている等、多くの利点を有している。
【0005】
メタル担体の製造に際しては、上記ハニカム体を外筒に嵌入し、ハニカム体と外筒の接触部が接合される。また、ハニカム体も、平箔と波箔の接触部が接合される。接合手段としては、ろう付け、電子ビーム溶接、レーザ溶接、抵抗溶接、拡散接合等が知られている。そして、接合の不十分な箇所があると、使用中に剥離し、メタル担体が破損するので、上記各接触部は確実に接合されていなければならない。したがって、材料に応じた適正な接合手段が採用されている。
【0006】
上記接合手段のうち、ろう付けはろう材が高価であるうえ、バインダ塗布、ろう材付着、真空加熱といった多くの工程を要し、製造コストも高くなる。電子ビーム溶接およびレーザ溶接は、高価な設備を要する。また、抵抗溶接は生産性が低く、量産には不向きである。これに対して、拡散接合は、接合面を清浄にした後、真空加熱炉等に装入し、非酸化性雰囲気で加熱するので、比較的簡単な工程で行うことができ、その全面的な採用が検討されている。
【0007】
しかし、上記のようなステンレス鋼を拡散接合するには、真空中で高温長時間の加熱が必要である。厚さ50μm程度の平箔と波箔を拡散接合して、ハニカム体を製造するには、たとえば1250℃で90分の加熱が行われる。また、ハニカム体と外筒を拡散接合してメタル担体を製造するには、外筒の肉厚が、たとえば1.5mmと、箔厚50μmに比べて厚いため、たとえば1250℃で120分といったさらに長時間の加熱が必要とされ、生産性およびエネルギー消費の両面で不利であった。このため、従来、箔同士を接合してハニカム体を製造する際には拡散接合を行い、ハニカム体と外筒を接合する際にはろう付けを行うのが一般的であった。
【0008】
なお、拡散接合によるハニカム体の製造に関し、平箔と波箔の接合不良に起因する接合強度不足の対策が、特開平5−123581号公報に提案されている。すなわち、平箔と波箔とを重ねて巻回し、真空中で高温保持して両箔を拡散接合する方法において、平箔を構成する材料組成と波箔を構成する材料組成とを異にすることで、両箔間の金属成分の濃度差により、相互拡散を促進させる方法である。具体的には、Fe−20Cr−5Al−0.06Yの波箔と、Fe−20Cr−5Al−0.06Y−0.1Tiの平箔を拡散接合した例が示されている。
【0009】
【発明が解決しようとする課題】
フェライト系ステンレス鋼製メタル担体の製造に際し、接合を全面的に拡散接合により行う技術の確立が切望されている。平箔と波箔の拡散接合を促進させてハニカム体を製造する技術に関しては、上記特開平5−123581号公報の技術があるが、本発明者らの実験によると、Tiのみの濃度差だけでは不十分であった。ハニカム体と外筒を拡散接合する技術に関しては、接合不良に起因して、安定した接合強度が得られず、未解決の問題が残されている。特に、TiあるいはNbを添加した材料では、拡散接合が困難であった。
【0010】
本発明者らは、TiやNbを添加した材料での拡散接合性の低下の原因を解析した結果、これらの材料では、真空熱処理時に、表面にTiやNbが析出し、その一部は炭化物となり、また一部は窒化物や酸化物となるなどして、金属同士の接触を妨げることに起因することを知見した。
【0011】
しかして本発明は、各種内燃機関の排ガス浄化用等に使用される触媒用メタル担体であって、TiとNbの一方または双方を添加したフェライト系ステンレス鋼からなり、平箔と波箔が重ねて渦巻状に巻回され、または交互に積層されたハニカム体が、外筒に嵌入されて形成されたメタル担体において、平箔、波箔、および外筒の各接触部が、いすれも拡散接合により接合されており、接合不良による接合強度不足が解消された触媒用メタル担体、その製造方法およびメタル担体用箔を提供することを目的とする。
【0012】
【課題を解決するための手段】
上記目的を達成するための本発明の第1発明は、質量%でC:0.05%以下、Si:1.0%以下、Mn:1.0%以下、Cr:11〜30%、Al:1〜6%、N:0.03%以下、P:0.05%以下、S:0.01%以下を含有するフェライト系ステンレス鋼からなり、平箔と波箔が重ねて渦巻状に巻回され、または交互に積層されたハニカム体が外筒に嵌入されて形成されたメタル担体において、前記平箔と波箔の表面粗さを、平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方を含有するとともに、各成分の含有量が(1)式の関係を満足し、
[Nb]+2[Ti]≦8[C]+48/7[N]+3[S]+6[O]+0.1
(1)
ただし、[Nb]、[Ti]、[C]、[N]、[S]、[O]は、それぞれNb、Ti、C、N、S、Oの含有量(質量%)
かつ、前記平箔、波箔、および外筒の各接触部が拡散接合により接合されていることを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体である。
【0013】
第2発明は、質量%でC:0.05%以下、Si:1.0%以下、Mn:1.0%以下、Cr:11〜30%、Al:1〜6%、N:0.03%以下、P:0.05%以下、S:0.01%以下を含有するフェライト系ステンレス鋼からなり、平箔と波箔が重ねて渦巻状に巻回され、または交互に積層されたハニカム体が外筒に嵌入されて形成されたメタル担体において、前記平箔と波箔の表面粗さを、平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方、およびYを含む希土類元素の合計:0.005〜0.2%を含有するとともに、各成分の含有量が(2)式の関係を満足し、
[Nb]+2[Ti]≦8[C]+48/7[N]+0.1 (2)
ただし、[Nb]、[Ti]、[C]、[N]は、それぞれNb、Ti、C、Nの含有量(質量%)
かつ、前記平箔、波箔、および外筒の各接触部が拡散接合により接合されていることを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体である。
【0014】
本発明においては、上記の如く、請求項1に係る触媒用メタル担体を第1発明、請求項2に係る触媒用メタル担体を第2発明としたが、以下の説明においても同様とする
第1発明および第2発明において、外筒とハニカム体の間に、フェライト系ステンレス鋼からなる中間筒が嵌入され、該中間筒が外筒およびハニカム体と拡散接合されていることが好ましい。(請求項3)
さらに、Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることが好ましい。(請求項4)
また、Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりも中間筒を構成するステンレス鋼の方が大であり、かつ中間筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該各含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることが好ましい。(請求項5)
【0015】
次に本発明においては、第1発明または第2発明のメタル担体の製造に際し、平箔と波箔を重ねて渦巻状に巻回し、または交互に積層してハニカム体を形成し、該ハニカム体を外筒に嵌入し、真空度9×10−4Torr以下の高真空下で拡散接合することを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体の製造方法を提供するものである。(請求項6)
上記の製造方法においては、平箔と波箔の接触幅が30μm以上となる波形状の波箔を用いることが好ましい。(請求項7)
【0016】
更に、本発明においては、
質量%でC:0.05%以下、Si:1.0%以下、Mn:1.0%以下、Cr:11〜30%、Al:1〜6%、N:0.03%以下、P:0.05%以下、S:0.01%以下を含有するフェライト系ステンレス鋼箔であって、その平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方を含有するとともに、各成分の含有量が下記(1)式、
[Nb]+2[Ti]≦8[C]+48/7[N]+3[S]+6[O]+0.1
(1)
ただし、[Nb]、[Ti]、[C]、[N]、[S]、[O]は、それぞれNb、Ti、C、N、S、Oの含有量(質量%)
の関係を満足することを特徴とする拡散接合用のメタル担体用箔(請求項8)、および
質量%でC:0.05%以下、Si:1.0%以下、Mn:1.0%以下、Cr:11〜30%、Al:1〜6%、N:0.03%以下、P:0.05%以下、S:0.01%以下を含有するフェライト系ステンレス鋼箔であって、その平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方、およびYを含む希土類元素の合計:0.005〜0.2%を含有するとともに、各成分の含有量が下記(2)式、
[Nb]+2[Ti]≦8[C]+48/7[N]+0.1 (2)
ただし、[Nb]、[Ti]、[C]、[N]は、それぞれNb、Ti、C、Nの含 有量(質量%)
の関係を満足することを特徴とする拡散接合用のメタル担体用箔(請求項9)、
を提供するものである。
【0017】
【発明の実施の形態】
本発明におけるメタル担体は、フェライト系ステンレス鋼からなり、図1に示すように、ハニカム体1が、外筒2に嵌入されて形成され、ハニカム体1は、ステンレス鋼箔3の壁で仕切られた多数の通気孔4を有している。ハニカム体1は、図2に示すように、帯状の平箔5と波箔6を重ね、平箔5にバックテンションをかけながら、軸7の回りに渦巻状に巻回して形成されるか、または、図3に示すように、平板状の平箔5と波箔6を交互に積層してされる。波箔6は、平箔5をコルゲート加工して形成することができる。
【0018】
本発明の第1発明は、上記のようなメタル担体におけるフェライト系ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方を含有するとともに、各成分の含有量が(1)式の関係を満足し、かつ、平箔、波箔、および外筒の各接触部が、拡散接合により接合されている。
[Nb]+2[Ti]≦8[C]+48/7[N]+3[S]+6[O]+0.1
(1)
ただし、[Nb]、[Ti]、[C]、[N]、[S]、[O]は、それぞれ、Nb、Ti、C、N、S、Oの含有量(質量%)である。
【0019】
Tiは、箔および管の製造性向上のために添加する。ステンレス鋼箔は、ホットコイルを冷間圧延し焼鈍した冷延鋼帯を、さらに箔圧延機で、50μmあるいはそれ以下の厚さに冷間圧延して製造される。また、外筒はステンレス鋼管から製造され、該管は、前記冷延鋼帯をシーム溶接して製造される。フェライト系ステンレス鋼においては、ホットコイルの靭性が劣るため、冷間圧延性に問題が生じる場合がある。したがって、Tiを0.02%以上添加することで、固溶C,Nを固定し、ホットコイルの靭性を改善する。しかし、過剰に添加すると、粗大なTi系析出物を形成して熱間加工性が劣化し、またホットコイルの靭性がかえって劣化するので、0.3%以下とする。なお、ホットコイルを焼鈍すれば靭性は改善されるので、その場合は、Ti無添加とすることもできる。
【0020】
Nbは、ホットコイルの靭性を改善するとともに、メタル担体の高温強度向上のために添加する。Nbを0.04%以上添加することで、炭窒化物析出により、高温での耐力が向上する。しかし、過剰に添加すると、Nb系金属間化合物を形成して、熱間加工性およびホットコイルの靭性が劣化するので、0.4%以下とする。なお、メタル担体の使用環境が、さほどの高温強度を必要としない場合は、Nb無添加とすることもできる。
【0021】
また、TiとNbを上記範囲で複合添加すると、Ti系炭窒化物の微細析出とNbの固溶とによって、メタル担体の高温強度が安定してより向上する。そして、高温長時間の加熱によっても、金属組織がほとんど変化しないので、高温強度の経時低下が抑制される。
【0022】
ところで、上記のようにTiとNbの一方または双方を添加した場合、拡散接合で接合不良が生じることがあった。そこで、本発明の第1発明では、TiおよびNbの含有量を、C,N,S,Oの含有量との関係で、(1)式を満足する範囲とすることにより、接合不良の問題を解決した。
【0023】
TiとNbの一方または双方が過剰に添加されていると、ステンレス鋼の表面に炭窒化物等が析出して、拡散接合時、各原子の相互拡散が阻害され、接合不良が生じた。炭素源および窒素源としては、ステンレス鋼中の固溶炭素および窒素のほか、拡散接合時の加熱炉雰囲気中に微量存在する炭素および窒素もあるが、TiとNbの添加量を(1)式を満足する範囲とすることで、表面での炭窒化物等の析出が抑えられ、問題が解決された。
【0024】
つぎに、本発明の第2発明は、上記のようなメタル担体におけるフェライト系ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方、およびYを含む希土類元素の合計:0.005〜0.2%を含有するとともに、各成分の含有量が(2)式の関係を満足し、かつ、平箔、波箔、および外筒の各接触部が、拡散接合により接合されている。
[Nb]+2[Ti]≦8[C]+48/7[N]+0.1 (2)
ただし、[Nb]、[Ti]、[C]、[N]は、それぞれNb、Ti、C、Nの含有量(質量%)である。
【0025】
第2発明においては、TiとNbの一方または双方を、上記第1発明と同様の理由で添加し、さらに、Yを含む希土類元素を添加する。ここで、希土類元素は、分離されたLa、Ce等のほか、Ln(ランタノイド)と呼ばれる分離精製されてない軽希土類元素の集合体(ミッシュメタル)を含む。これらの希土類元素は、単独または複合で添加し、メタル担体が、特に950℃以上で使用される場合の耐高温酸化性向上のため、添加量を合計で0.005%以上とする。しかし、過剰に添加すると、耐酸化性が低下するとともに、熱間加工性が悪化するので、0.2%以下とする。
【0026】
そして、第2発明においては、TiとNbの一方または双方の添加量を(2)式の範囲とすることで、TiやNbの炭窒化物等がステンレス鋼表面に析出するのが抑制され、拡散接合における接合不良の問題が解決される。なお、第2発明では、Yを含む希土類元素が上記範囲添加されているので、第1発明と異なり、鋼中のSおよびOの影響がなくなる。
【0027】
上記第1発明および第2発明において、フェライト系ステンレス鋼のその他の成分は、ハニカム体にはAl添加材、外筒にはAl添加材あるいはAl無添加材で、通常使用されている範囲のものとすることができる。すなわち、
Crは、11%未満では、メタル担体としての基本的な耐食性および耐酸化性が不足し、30%超では、ホットコイルの靭性が低下し製造性が損なわれるので、11〜30%とする。
【0028】
Alは、Al皮膜の形成により、メタル担体の耐高温酸化性を向上させるため、ハニカム体を構成するステンレス鋼には1%以上添加する。6%超では、ホットコイルの靭性が低下し製造性が損なわれるほか、熱膨張係数が大きくなり、触媒担体としての使用時、加熱と冷却の繰返しによる熱疲労が問題となる。したがって、1〜6%とする。しかし、外筒は高温の排ガスに接しないか、あるいは接する機会が少ないので、Al無添加の材料を採用することもできる。
【0029】
Cは不可避的不純物として混入するが、0.05%超ではホットコイルの靭性が低下するので、その上限を0.05%とする。
Nも不可避的不純物として混入するが、0.03%超ではホットコイルの靭性が低下するので、その上限を0.03%とする。
【0030】
Siも不可避的不純物で、1%超ではAl皮膜の生成に障害が生じ、ホットコイルの靭性にも悪影響を及ぼすので、その上限を1%とする。
Mnも不可避的不純物で、1%超ではホットコイルの靭性が劣化するので、その上限を1%とする。
【0031】
Pも不可避的不純物ながら、希土類元素を添加した場合は、Pを高めにすることにより、熱間加工性が向上する。さりながら、0.05%超ではホットコイルの靭性が劣化するので、その上限を0.05%とする。
Sも不可避的不純物で、0.01%超では耐酸化性に悪影響を及ぼすので、その上限を0.01%とする。
【0032】
第1および第2の発明においては、平箔と波箔の表面粗さを、平均粗さ(Ra)で0.001μm以上0.2μm以下とし、該平箔と該波箔を重ねて渦巻状に巻回し、または交互に積層してハニカム体を形成し、該ハニカム体を外筒に嵌入して拡散接合することにより、強度の高い接合が得られる。
【0033】
一般に、拡散接合においては、接合すべき材料同士が密着している必要があり、かつ接触部には加熱中も面圧が加わるよう、加圧装置あるいはウエイトが使用される。しかし、メタル担体の場合は、その構造の特異性により、外部から面圧を付与することが困難であるため、図2のようなハニカム体巻回時に平箔5に付与される限られた張力のバックテンションや、ハニカム体を外筒に嵌入した後の縮径により得られる比較的小さな面圧、あるいは中間筒の嵌入により付与される面圧のもとで拡散接合を実施する必要がある。
【0034】
本発明者らは、このような比較的小さな面圧下での拡散接合性を向上させる方法を探索した結果、接合界面における平箔および波箔の表面粗さを小さくすることが有効であることを知見した。実験の結果、平箔および波箔の平均粗さ(Ra)を0.2μm以下にすると、極めて容易に良好な拡散接合部が得られた。そして、Raを0.001μm未満に平滑化しても、拡散接合性に与える影響は飽和した。なお、外筒内面の表面粗さを、Raで0.001μm以上0.2μm以下とすることにより、ハニカム体と外筒の拡散接合性が同様に向上することを確認した。したがって、本発明では、上記のように表面粗さを限定した。
【0035】
このような第1発明および第2発明のメタル担体は、平箔と波箔との接触部、およびハニカム体と外筒の接触部をともに拡散接合により、同時に接合して製造することができ、十分な接合強度を有している。拡散接合の手段としては、真空炉等の非酸化性雰囲気炉で加熱する方法を採用できる。なお、従来、Fe−Cr−Al系のフェライト系ステンレス鋼からなるメタル担体において、拡散接合の際、加熱雰囲気中の微量酸素と鋼中のAlが反応して、Al皮膜が生成し、拡散が阻害されるおそれがあったが、本発明では、各接触部が密着しているうえ、上記のように、各接触部の界面にはTiやNbの炭窒化物等の表面への析出が抑制されているので、Al皮膜による接合不良の問題は生じない。
【0036】
つぎに、第1発明および第2発明において、外筒とハニカム体の間に、フェライト系ステンレス鋼からなる中間筒が嵌入され、該中間筒が外筒およびハニカム体と拡散接合されていることが好ましい。中間筒の材料としては、上記Al添加材、あるいはAl無添加材を採用できる。中間筒は、図4の各展開図例に示すように、切込み9を有しており、図5に示すように、ハニカム体1と外筒2の間に嵌入したとき、中間筒8がばね作用をなす。
【0037】
このため、外筒2と中間筒8、中間筒8とハニカム体1、さらにはハニカム体1の平箔5と波箔6の各接触部において、接触面圧が高まり密着性が向上する。したがって、これを非酸化性雰囲気で加熱し、拡散接合して得られる第1発明および第2発明のメタル担体は、接合強度がより向上したものである。
【0038】
さらに、第1発明および第2発明において、Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることが好ましい。このような本発明は、比較的厚手の外筒と、箔からなるハニカム体との拡散接合において、両者の主要成分の含有量に上記の差を有しているため、相互拡散が促進され、成分差のない場合と同一条件での拡散接合で、接合強度がより向上したメタル担体となる。
【0039】
Cr含有量のみが差を有する場合は、1.0%以上の差で、接合強度に明瞭な効果が現れ、差が増す程、接合強度が高くなる。Al含有量のみが差を有する場合は、0.5%以上の差で、上記Crの場合と同様、接合強度に明瞭な効果が現れ、差が増す程、接合強度が高くなる。また、CrとAlの双方が差を有すると、効果がより向上するが、各成分差は上記のとおりでよい。なお、Cr、Alとも、ハニカム体の方を含有量大としたのは、高温の排ガスに接してより高温になるからである。
【0040】
また、第1発明および第2発明において、中間筒を有する場合、Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりも中間筒を構成するステンレス鋼の方が大であり、かつ中間筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることが好ましい。効果および各成分差の限定理由は上記のとおりである。また、Cr、Alとも、ハニカム体を構成するステンレス鋼を含有量最大とし、外筒を最小としたのは、ハニカム体が最も高温となり、つぎに中間筒、そのつぎが外筒の順となるからである。
【0041】
なお、上記において、Cr含有量およびAl含有量の差は、拡散接合促進の観点からは大きい方がよく、上限については特に限定の必要はない。しかし、メタル担体としての耐食性、耐酸化性および耐熱疲労性、材料の製造性の観点から、使用環境に応じて、前述のように、ハニカム体はCr含有量11〜30%およびAl含有量1〜6%の範囲とし、外筒と中間筒はCr含有量11〜30%およびAl含有量0〜6%の範囲とするので、含有量の差の上限は、Crについては19%、Alについては6%となる。
【0042】
つぎに、本発明に係るメタル担体の製造方法は、第1発明または第2発明のメタル担体の製造に際し、平箔と波箔を重ねて渦巻状に巻回し、または交互に積層してハニカム体を形成し、該ハニカム体を外筒に嵌入し、真空度9×10−4Torr以下の高真空下で拡散接合することを特徴とする。ハニカム体の平箔と波箔は接合しない状態で外筒に嵌入し、上記高真空下で高温加熱することにより、外筒とハニカム体、およびハニカム体の平箔と波箔の各接触部が拡散接合され、十分な接合強度が得られる。真空度が上記9×10−4Torrを超えた低真空下では、各接触部にAl皮膜が生成して、相互拡散が阻害されるおそれがある。加熱条件としては、1250〜1300℃、60〜120分とすることができる。
【0043】
また、上記の本発明の製造方法において、ハニカム体と外筒の間に、フェライト系ステンレス鋼からなる中間筒を嵌入し、真空度9×10−4Torr以下の高真空下で拡散接合することもできる。この場合も、ハニカム体の平箔と波箔は接合しない状態とし、中間筒、外筒を嵌合させ、上記高真空下で高温加熱することにより、外筒と中間筒、中間筒とハニカム体、およびハニカム体の平箔と波箔の各接触部が拡散接合され、十分な接合強度が得られる。
【0044】
さらに、上記の本発明の製造方法において、ハニカム体と外筒、あるいはさらに中間筒を構成するステンレス鋼の、Cr含有量とAl含有量の一方または双方が、上記第1発明および第2発明の好ましい態様と同様の差を有したものとすることができる。これにより、拡散接合後の接合強度がより強固なものとなる。
【0045】
本発明の製造方法においては、図6に示すように、平箔5と波箔6の接触幅14が30μm以上となる波形状の波箔を用いることが好ましい。このような波箔を使用することにより、平箔と波箔の接触面積が増大し、拡散接合性がより向上する。この場合、波箔6の形状は台形状とし、コルゲート加工時に、歯車ロールの歯形を変える等により形成することができる。
【0046】
また、本発明の製造方法においては、ハニカム体と外筒の間に、フェライト系ステンレス鋼からなる中間筒を嵌入することもできる。この場合も、ハニカム体の平箔と波箔は接合しないで中間筒、外筒を嵌合させ、外筒と中間筒、中間筒とハニカム体、およびハニカム体の平箔と波箔の各接触部が拡散接合され、十分な接合強度が得られる。なお、中間筒の内外面の表面粗さを、Raで0.001μm以上0.2μm以下とすることにより、中間筒とハニカム体および外筒との拡散接合性がより向上する。
【0047】
以上述べた本発明の第1発明および第2発明の触媒用メタル担体、および、上述した製造方法により製造された触媒用メタル担体は、ハニカム体のステンレス鋼箔表面に、活性アルミナ等の耐熱多孔質層(ウォッシュコート層)を形成し、該層にPt等の貴金属からなる触媒を担持させ、内燃機関の排ガス経路に装着される。
【0048】
【実施例】
[実施例1]
第1発明および第2発明の例として、表1の成分からなる各Fe−Cr−Al系フェライト系ステンレス鋼の冷延板から50+μm厚の帯状平箔を製造し、該平箔の一部をコルゲート加工して波箔を製造した。得られた平箔と波箔を、図2のように重ねて巻回し、直径80mm、長さ120mmのハニカム体を形成した。また、表2のAの組成の冷延板の板厚1.5mm材からシーム溶接管を製造し、外径83mm、肉厚1.5mm、長さ120mmの外筒を形成した。
【0049】
外筒内に上記ハニカム体を嵌入し、真空加熱炉に装入して、3×10−4Torrの真空度を保ちつつ、1250℃で90分加熱保定し、外筒とハニカム体の最外周、およびハニカム体の平箔と波箔を拡散接合した。
拡散接合したメタル担体の接合強度を調べるため、図7(a)に示すように、厚さ20mmの円盤状の試験片11を6個切出した。10は切断面である。そして、図7(b)のように、試験片11の外筒2の部分を円筒状の受け台13に載置し、ハニカム体1の部分に上方から段付きポンチ12を押し当て、接合部が破断するときの荷重(押抜き荷重)を測定した。
【0050】
各メタル担体の、6個の試験片についての押抜き荷重の平均値を表1に示す。本発明例は、いずれも押抜き荷重が高く、優れた接合強度を有している。なお、この押抜き荷重が350kg以上あれば、実際の排ガス経路に装着し、使用したときの損傷に対して、問題ないことを確認している。比較例のNo.25およびNo.26は、(1)式が不成立であるため、またNo.27およびNo.28は、REM添加で(2)式が不成立であるため、押抜き荷重が低く、所要の接合強度が得られていない。
【0051】
【表1】

Figure 0003816974
【0052】
【表2】
Figure 0003816974
【0053】
[実施例2]
第1発明の好ましい例として、表1のNo.5およびNo.7について、中間筒を嵌入したメタル担体を製造した。中間筒は、外径81mm、肉厚0.5mmで、図4(a)の展開図に示すような切込み9を入れたものとし、外径84mm、肉厚1.5mmの外筒とハニカム体の間に嵌入した。その他の条件は上記実施例1と同様であり、実施例1と同様の条件で拡散接合し、押抜き荷重を測定した。その結果、No.5は600kg、No.7は620kgであり、中間筒により、接合強度が向上した。また、図4(b)および(c)のような切込みを入れたものも同様の効果があり、図4(d)のような切込みを入れたものは、やや劣るものの効果が認められた。
【0054】
[実施例3]
第1発明および第2発明の別の好ましい例として、表1に示すハニカム体用材のうちの5種類(No.4、No.6、No.17、No.21、No.25)のものと、表2に示す6種類のステンレス鋼を組合わせて、表3に示す9種類のメタル担体を製造した。表3の記号イ〜ニ、ト、チは上記実施例1と同様の条件で、記号ホ、ヘ、リは実施例2と同様の条件で製造した。表2の各ステンレス鋼は、いずれも第1発明の範囲の成分である。
【0055】
各メタル担体の押抜き荷重を表3に示す。本発明例の記号イは、Al含有量が外筒よりハニカム体の方が大であり(外筒はAl無添加)、その差が0.5%以上あるため、Cr含有量には差がないが、比較例の記号チより押抜き荷重が高い。本発明例の記号ロ〜ニは、Cr含有量およびAl含有量が、外筒よりもハニカム体の方が大であり(外筒はいずれもAl無添加)、その差がCrで1.0%以上、Alで0.5%以上あるため、いずれも、比較例の記号チより押抜き荷重が高い。
【0056】
比較例の記号トは、外筒に(1)式不成立の表1No.25からなるステンレス鋼を採用したため、また、ハニカム体と外筒のCr含有量が同じであり、Al含有量は異なるが、差が0.5%未満であるため、押抜き荷重が低い。比較例の記号チは、第1発明の条件を満たしているので、押抜き荷重が410kgと高いが、CrおよびAlの双方とも、ハニカム体と外筒で含有量に差がないので、本発明例の記号イ〜ニよりも低い。
【0057】
本発明例の記号ホおよびヘは、中間筒を有するものである。記号ホは、Cr含有量およびAl含有量が、外筒より中間筒の方が、また中間筒よりハニカム体の方が大であり、その差がいずれもCrで1.0%以上、Alで0.5%以上あるため、押抜き荷重が高い。記号ヘは、中間筒と外筒のAl含有量の差が0.09と小さいが、Crの差が1.0%以上あり、かつハニカム体と中間筒の差がCrで1.0%以上、Alで0.5%以上あるので、押抜き荷重が高い。
これに対して、比較例の記号リは、中間筒を有するが、ハニカム体に(1)式不成立の表1No.25からなるステンレス鋼を採用したため、また、中間筒と外筒のCr含有量およびAl含有量に差がないため、押抜き荷重が低い。
【0058】
【表3】
Figure 0003816974
【0059】
【表4】
Figure 0003816974
【0060】
[実施例4]
第3発明の例として、表3に示す記号イ、ロ、ハ、ニ、ホの5種類のメタル担体を製造するにあたり、拡散接合における真空度を変化させた。すなわち、箔が接合されていないハニカム体を外筒に嵌入し(イ〜ニ)、また、ハニカム体と外筒の間に中間筒を嵌合させ(ホ)、真空加熱炉に装入して拡散接合した。炉内の真空度は、3×10−3Torr、9×10−4Torr、3×10−4Torr、1×10−4Torrの4水準、加熱条件は、いずれも1250℃で90分加熱保定とした。
接合後の各メタル担体の押抜き荷重は、表4に示すとおり、真空度が比較例の3×10−3Torrでは、低い値であったが、本発明例の9×10−4Torr以下では、いずれも十分高い値であった。
【0061】
【表5】
Figure 0003816974
【0062】
[実施例5]
第4発明の例として、平箔および波箔の表面粗さを変化させ、かつ平箔と波箔の接触幅を変化させてメタル担体を製造した。表1No.8(20Cr−5Al−0.3Nb)の組成からなる、50μm厚の平箔および波箔を、図2のように重ね、平箔5に12kgfのバックテンションをかけながら、渦巻状に巻回して、外径80mm、長さ120mmのハニカム体を形成した。
【0063】
巻回前の平箔および波箔の表面粗さを、平均粗さ(Ra)で0.001μm、0.01μm、0.1μm、0.2μm、0.3μmの5水準とし、また、巻回後の両箔の、図6に示す接触幅14を、20μm、30μm、50μm、200μmの4水準とした。接触幅は、平箔を歯車ロールでコルゲート加工して波箔を形成する際、歯車ロールの歯形を変え、波形状の異なる波箔を形成することで変化させた。
【0064】
また、表2のA(11Cr−0.1Ti)の組成の1.5mm厚の冷延材からシーム溶接管を製造し、外径83mm、肉厚1.5mm、長さ120mmの外筒を形成した。そして、外筒内にハニカム体を嵌入し、真空加熱炉に装入して、3×10−4Torrの真空度を保ちつつ、1250℃で90分加熱保持し、外筒とハニカム体の最外周、およびハニカム体の平箔と波箔を拡散接合した。
【0065】
得られた各メタル担体について、外筒の軸直交面で切断し切り出した試験片を樹脂に埋め込み、該軸直交面を研磨したのち、ハニカム体の外周から20層分の各接点を観察し、拡散接合率を求めた。拡散接合率は、接合点数/全接点数である。結果は、表5に示すように、表面粗さ0.2μm以下、接触幅30μm以上の領域で、拡散接合率が0.60以上であった。そして、この領域のメタル担体を、ガソリンエンジンの排気系に搭載し、1サイクル;加熱900℃×10分+冷却室温×10分の耐久試験を900サイクル実施したところ、全て合格であった。
【0066】
【表6】
Figure 0003816974
【0067】
【発明の効果】
本発明の触媒用メタル担体は、ハニカム体の平箔と波箔、外筒とハニカム体の各接触部がいずれも拡散接合により強固に接合されている。従来、メタル担体における拡散接合は、生産性を阻害しない範囲では、十分な接合強度が得られない場合があるため、一部ろう付け接合が行われていたが、本発明によれば、拡散接合のみで強固な安定した接合強度が得られる。したがって、ハニカム体の平箔と波箔、およびハニカム体の最外層と外筒等の各接触部を、拡散接合により同時に接合することで、製造工程が簡易化し、かつろう材等の材料費や工程費が節減される。
【図面の簡単な説明】
【図1】 本発明メタル担体の構造例を示す斜視図である。
【図2】 本発明メタル担体におけるハニカム体の製造例を示す斜視図である。
【図3】 本発明メタル担体におけるハニカム体の構造例を示す正面図である。
【図4】 本発明メタル担体における中間筒の構造例を示す展開図である。
【図5】 本発明メタル担体において中間筒を嵌入した例を示す縦割り斜視図である。
【図6】 本発明法における平箔と波箔の接触状態を示す部分拡大正面図である。
【図7】 実施例における接合強度の測定方法を示す説明図である。
【符号の説明】
1…ハニカム体 2…外筒
3…ステンレス鋼箔 4…通気孔
5…平箔 6…波箔
7…軸 8…中間筒
9…切込み 10…切断面
11…試験片 12…段付きポンチ
13…受け台 14…接触幅[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a diffusion-bonded catalyst metal carrier having a strong bonding strength suitable for exhaust gas purification of various internal combustion engines.And its manufacturing method and metal carrier foilIt is about.
[0002]
[Prior art]
  In recent years, a metal carrier in which a honeycomb body made of stainless steel is inserted into a heat-resistant stainless steel outer cylinder has been widely used as a carrier for exhaust gas purification catalysts of various internal combustion engines such as automobiles, boilers, and power generation. I came. The honeycomb body is formed by winding a flat strip having a thickness of about 50 μm and a corrugated strip-shaped corrugated foil and winding them in a spiral shape, or by alternating both flat foils. The one formed by laminating is used.
[0003]
  As the stainless steel, Fe-Cr-Al ferritic stainless steel, such as Fe-20% Cr-5% Al, which has excellent oxidation resistance in a high-temperature exhaust gas atmosphere, is often used for the honeycomb body. In addition, ferritic diameter stainless steel with no addition of Al is also employed. In addition, various characteristics are improved by additive elements, for example, Ti is added for improving workability, Nb is added for improving high-temperature strength, and oxidation resistance is further improved. For this reason, those to which rare earth elements such as La and Ce are added are known.
[0004]
  Since such a metal carrier has a smaller heat capacity than a conventional ceramic carrier, it is heated quickly to a temperature at which the catalyst acts, and has an excellent exhaust gas purification ability at the initial stage of engine start. Moreover, since the walls of the honeycomb body are made of a thin metal foil, the exhaust resistance is small and the loss of engine output is small. Furthermore, it has many advantages such as excellent durability even in an exhaust gas environment where the temperature rises and falls severely.
[0005]
  In manufacturing the metal carrier, the honeycomb body is fitted into the outer cylinder, and the contact portion between the honeycomb body and the outer cylinder is joined. In addition, the contact portion between the flat foil and the corrugated foil is also bonded to the honeycomb body. As joining means, brazing, electron beam welding, laser welding, resistance welding, diffusion joining, and the like are known. And if there is an insufficiently bonded part, it will be peeled off during use and the metal carrier will be damaged, so that each of the contact parts must be securely bonded. Therefore, an appropriate joining means corresponding to the material is employed.
[0006]
  Among the above-mentioned joining means, brazing is expensive in brazing material, and requires many steps such as binder coating, brazing material adhesion, and vacuum heating, resulting in high manufacturing costs. Electron beam welding and laser welding require expensive equipment. Resistance welding is low in productivity and is not suitable for mass production. On the other hand, diffusion bonding can be performed in a relatively simple process since it is charged in a vacuum heating furnace after heating the bonding surface and heated in a non-oxidizing atmosphere. Adoption is being considered.
[0007]
  However, in order to perform diffusion bonding of stainless steel as described above, heating at a high temperature for a long time is required in a vacuum. In order to manufacture a honeycomb body by diffusion bonding of a flat foil having a thickness of about 50 μm and a corrugated foil, for example, heating is performed at 1250 ° C. for 90 minutes. In addition, to manufacture a metal carrier by diffusion bonding the honeycomb body and the outer cylinder, the outer cylinder has a thickness of, for example, 1.5 mm, which is larger than the foil thickness of 50 μm. Long heating was required, which was disadvantageous in terms of both productivity and energy consumption. For this reason, conventionally, diffusion bonding is generally performed when manufacturing a honeycomb body by bonding foils, and brazing is performed when bonding a honeycomb body and an outer cylinder.
[0008]
  Incidentally, regarding the manufacture of honeycomb bodies by diffusion bonding, a countermeasure for insufficient bonding strength due to defective bonding between a flat foil and a corrugated foil is proposed in JP-A-5-123581. That is, in a method in which flat foil and corrugated foil are overlapped and wound, and held at high temperature in a vacuum and both foils are diffusion-bonded, the material composition constituting the flat foil differs from the material composition constituting the corrugated foil. Thus, it is a method of promoting mutual diffusion by the difference in concentration of the metal component between the two foils. Specifically, an example in which a corrugated foil of Fe-20Cr-5Al-0.06Y and a flat foil of Fe-20Cr-5Al-0.06Y-0.1Ti are diffusion bonded is shown.
[0009]
[Problems to be solved by the invention]
  In producing a ferritic stainless steel metal carrier, it is desired to establish a technique for performing bonding entirely by diffusion bonding. Regarding a technique for manufacturing a honeycomb body by promoting diffusion bonding between a flat foil and a corrugated foil, there is a technique of the above-mentioned Japanese Patent Application Laid-Open No. 5-123581, but according to experiments conducted by the present inventors, only a concentration difference of Ti is obtained. It was not enough. Regarding the technique for diffusion bonding the honeycomb body and the outer cylinder, a stable bonding strength cannot be obtained due to poor bonding, and an unsolved problem remains. In particular, diffusion bonding is difficult with a material to which Ti or Nb is added.
[0010]
  As a result of analyzing the cause of the decrease in diffusion bonding property in materials added with Ti or Nb, the present inventors have found that Ti and Nb are precipitated on the surface during vacuum heat treatment, and some of them are carbides. It has also been found that this is caused by blocking the contact between metals, for example, by becoming nitrides or oxides.
[0011]
  Therefore, the present invention is a catalyst metal carrier used for exhaust gas purification of various internal combustion engines, which is made of ferritic stainless steel to which one or both of Ti and Nb are added, and a flat foil and a corrugated foil are laminated. In a metal carrier formed by spirally winding or alternately laminating honeycomb bodies that are inserted into the outer cylinder, each contact portion of the flat foil, corrugated foil, and outer cylinder is diffused. Metal carrier for catalyst that has been joined by joining, and lack of joining strength due to joining failure,Method for producing the same and foil for metal carrierThe purpose is to provide.
[0012]
[Means for Solving the Problems]
  In order to achieve the above object, the first invention of the present invention comprises:mass%: C: 0.05% or less, Si: 1.0% or less, Mn: 1.0%Less than, Cr: 11 to 30%, Al: 1 to 6%, N: 0.03% or less, P: 0.05% or less, S: 0.01% or less, and a flat foil And a corrugated foil wound in a spiral shape, or in a metal support formed by inserting alternately laminated honeycomb bodies into an outer cylinder, the surface roughness of the flat foil and the corrugated foil is average roughness (Ra) is 0.001 μm or more and 0.2 μm or less, and the stainless steel ismass%, One or both of Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4%, and the content of each component satisfies the relationship of formula (1),
  [Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +3 [S] +6 [O] +0.1
                                                                      (1)
      However, [Nb], [Ti], [C], [N], [S], and [O] are the contents of Nb, Ti, C, N, S, and O, respectively (mass%)
In addition, the present invention provides a diffusion-bonded catalyst metal carrier having strong bonding strength, wherein the contact portions of the flat foil, corrugated foil, and outer cylinder are bonded by diffusion bonding.
[0013]
  The second invention ismass%: C: 0.05% or less, Si: 1.0% or less, Mn: 1.0%Less than, Cr: 11 to 30%, Al: 1 to 6%, N: 0.03% or less, P: 0.05% or less, S: 0.01% or less, and a flat foil And a corrugated foil wound in a spiral shape, or in a metal support formed by inserting alternately laminated honeycomb bodies into an outer cylinder, the surface roughness of the flat foil and the corrugated foil is average roughness (Ra) is 0.001 μm or more and 0.2 μm or less, and the stainless steel is, in mass%, one of Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4% or Both and the total of rare earth elements including Y: 0.005 to 0.2%, and the content of each component satisfies the relationship of the formula (2),
  [Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +0.1 (2)
      However, [Nb], [Ti], [C], and [N] are the contents of Nb, Ti, C, and N, respectively (mass%)
In addition, the present invention provides a diffusion-bonded catalyst metal carrier having strong bonding strength, wherein the contact portions of the flat foil, corrugated foil, and outer cylinder are bonded by diffusion bonding.
[0014]
  In the present invention, as described above, the metal carrier for catalyst according to claim 1 is the first invention, and the metal carrier for catalyst according to claim 2 is the second invention, but the same applies to the following description..
  In the first and second inventions, it is preferable that an intermediate cylinder made of ferritic stainless steel is inserted between the outer cylinder and the honeycomb body, and the intermediate cylinder is diffusion bonded to the outer cylinder and the honeycomb body.(Claim 3)
  Further, one or both of the Cr content and the Al content is larger in the stainless steel constituting the honeycomb body than the stainless steel constituting the outer cylinder, and the difference in the content ismass%, Cr is preferably 1.0% or more, and Al is preferably 0.5% or more.(Claim 4)
  Further, one or both of the Cr content and the Al content is larger in the stainless steel constituting the intermediate cylinder than the stainless steel constituting the outer cylinder, and the honeycomb body than the stainless steel constituting the intermediate cylinder The stainless steel constituting is larger, the difference in each content ismass%, Cr is preferably 1.0% or more, and Al is preferably 0.5% or more.(Claim 5)
[0015]
  Next, in the present inventionIn manufacturing the metal carrier of the first invention or the second invention, the flat foil and the corrugated foil are overlapped and spirally wound or alternately laminated to form a honeycomb body, and the honeycomb body is fitted into the outer cylinder. , Degree of vacuum 9 × 10-4It is an object of the present invention to provide a method for producing a diffusion-bonded catalyst metal carrier having strong bonding strength, characterized by diffusion bonding under a high vacuum of Torr or less.(Claim 6)
  In the above manufacturing method, it is preferable to use a corrugated corrugated foil having a contact width of 30 μm or more between the flat foil and corrugated foil. (Claim 7)
[0016]
  Furthermore, in the present invention,
  C: 0.05% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11-30%, Al: 1-6%, N: 0.03% or less, P : Ferritic stainless steel foil containing 0.05% or less, S: 0.01% or less,The average roughness (Ra) is 0.001 μm or more and 0.2 μm or less, and the stainless steel ismass%, One or both of Ti: 0.02-0.3% and Nb: 0.04-0.4%, and the content of each component isfollowing(1) Formula,
  [Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +3 [S] +6 [O] +0.1
                                                                      (1)
    However, [Nb], [Ti], [C], [N], [S], and [O] are the contents of Nb, Ti, C, N, S, and O, respectively (mass%)
Satisfy the relationshipA metal carrier foil for diffusion bonding (claim 8), and
  C: 0.05% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11-30%, Al: 1-6%, N: 0.03% or less, P : Ferritic stainless steel foil containing 0.05% or less, S: 0.01% or less,The average roughness (Ra) is 0.001 μm or more and 0.2 μm or less, and the stainless steel ismass%, One or both of Ti: 0.02-0.3% and Nb: 0.04-0.4%And total of rare earth elements including Y: 0.005 to 0.2%And the content of each component isBelow (2)formula,
  [Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +0.1 (2)
    However, [Nb], [Ti], [C], and [N] include Nb, Ti, C, and N, respectively. Amount (mass%)
Satisfy the relationshipMetal carrier foil for diffusion bonding(Claim 9),
Is to provide.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  The metal carrier in the present invention is made of ferritic stainless steel, and as shown in FIG. 1, the honeycomb body 1 is formed by being fitted into the outer cylinder 2, and the honeycomb body 1 is partitioned by the wall of the stainless steel foil 3. A large number of ventilation holes 4 are provided. As shown in FIG. 2, the honeycomb body 1 is formed by stacking a strip-shaped flat foil 5 and a corrugated foil 6 and spirally winding the flat foil 5 around a shaft 7 while applying a back tension. Alternatively, as shown in FIG. 3, flat flat foils 5 and corrugated foils 6 are alternately laminated. The corrugated foil 6 can be formed by corrugating the flat foil 5.
[0018]
  The first invention of the present invention is a ferritic stainless steel in the metal carrier as described above.mass%, One or both of Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4%, and the content of each component satisfies the relationship of formula (1), And each contact part of a flat foil, a corrugated foil, and an outer cylinder is joined by diffusion bonding.
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +3 [S] +6 [O] +0.1
                                                                          (1)
However, [Nb], [Ti], [C], [N], [S], and [O] are the contents of Nb, Ti, C, N, S, and O, respectively (mass%).
[0019]
  Ti is added to improve the productivity of foils and tubes. The stainless steel foil is manufactured by cold rolling a cold rolled steel strip obtained by cold rolling and annealing a hot coil to a thickness of 50 μm or less using a foil rolling machine. The outer cylinder is manufactured from a stainless steel pipe, and the pipe is manufactured by seam welding the cold-rolled steel strip. In ferritic stainless steel, the hot coil has poor toughness, which may cause problems in cold rollability. Therefore, by adding 0.02% or more of Ti, solid solution C and N are fixed, and the toughness of the hot coil is improved. However, if added excessively, coarse Ti-based precipitates are formed, and hot workability is deteriorated, and the toughness of the hot coil is deteriorated. Therefore, the content is made 0.3% or less. In addition, since the toughness is improved if the hot coil is annealed, in that case, Ti can be added.
[0020]
  Nb is added to improve the toughness of the hot coil and improve the high temperature strength of the metal carrier. By adding 0.04% or more of Nb, the yield strength at high temperature is improved by carbonitride precipitation. However, if added excessively, an Nb-based intermetallic compound is formed, and hot workability and hot coil toughness deteriorate, so the content is made 0.4% or less. In addition, when the use environment of a metal carrier does not require the high temperature intensity | strength, it can also be set as Nb non-addition.
[0021]
  Further, when Ti and Nb are added in combination within the above range, the high temperature strength of the metal carrier is stabilized and further improved by the fine precipitation of Ti-based carbonitride and the solid solution of Nb. And since the metal structure hardly changes even by heating at a high temperature for a long time, a decrease in high temperature strength with time is suppressed.
[0022]
  By the way, when one or both of Ti and Nb is added as described above, bonding failure may occur in diffusion bonding. Therefore, in the first invention of the present invention, the content of Ti and Nb is set in a range satisfying the expression (1) in relation to the contents of C, N, S, and O, thereby causing a problem of poor bonding. Solved.
[0023]
  When one or both of Ti and Nb were added excessively, carbonitrides and the like were deposited on the surface of stainless steel, interdiffusion of each atom was inhibited during diffusion bonding, and bonding failure occurred. Carbon sources and nitrogen sources include solid solution carbon and nitrogen in stainless steel, as well as carbon and nitrogen that exist in trace amounts in the furnace atmosphere during diffusion bonding. By satisfying the range, precipitation of carbonitrides and the like on the surface was suppressed, and the problem was solved.
[0024]
  Next, the second invention of the present invention, the ferritic stainless steel in the metal carrier as described above,mass%, Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4% or both, and the total of rare earth elements including Y: 0.005 to 0.2% At the same time, the content of each component satisfies the relationship of the expression (2), and the contact portions of the flat foil, the corrugated foil, and the outer cylinder are joined by diffusion bonding.
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +0.1 (2)
However, [Nb], [Ti], [C], and [N] are the contents of Nb, Ti, C, and N, respectively (mass%).
[0025]
  In the second invention, one or both of Ti and Nb are added for the same reason as in the first invention, and further a rare earth element containing Y is added. Here, the rare earth element includes, in addition to separated La, Ce, and the like, an aggregate of light rare earth elements (misch metal) called Ln (lanthanoid) that is not separated and purified. These rare earth elements are added alone or in combination, and the total amount added is 0.005% or more in order to improve high-temperature oxidation resistance when the metal carrier is used at 950 ° C. or more. However, if added in excess, the oxidation resistance decreases and the hot workability deteriorates, so the content is made 0.2% or less.
[0026]
  And in 2nd invention, by making the addition amount of one or both of Ti and Nb into the range of the formula (2), it is suppressed that carbonitrides such as Ti and Nb are precipitated on the stainless steel surface, The problem of poor bonding in diffusion bonding is solved. In the second invention, since the rare earth element containing Y is added in the above range, unlike the first invention, the influence of S and O in the steel is eliminated.
[0027]
  In the first and second inventions described above, the other components of the ferritic stainless steel are Al-added material for the honeycomb body and Al-added or non-Al-added material for the outer tube, and are within the range normally used. It can be. That is,
  If Cr is less than 11%, the basic corrosion resistance and oxidation resistance as a metal carrier are insufficient, and if it exceeds 30%, the toughness of the hot coil is reduced and manufacturability is impaired.
[0028]
  Al is Al2O3In order to improve the high temperature oxidation resistance of the metal carrier by forming a film, 1% or more is added to the stainless steel constituting the honeycomb body. If it exceeds 6%, the toughness of the hot coil is reduced and the manufacturability is impaired, and the coefficient of thermal expansion is increased, and thermal fatigue due to repeated heating and cooling becomes a problem when used as a catalyst carrier. Therefore, it is 1 to 6%. However, since the outer cylinder does not come into contact with the high-temperature exhaust gas or has few opportunities to come into contact therewith, it is possible to adopt a material containing no Al.
[0029]
  C is mixed as an inevitable impurity, but if it exceeds 0.05%, the toughness of the hot coil decreases, so the upper limit is made 0.05%.
  N is also mixed as an inevitable impurity, but if it exceeds 0.03%, the toughness of the hot coil decreases, so the upper limit is made 0.03%.
[0030]
  Si is also an inevitable impurity, and if it exceeds 1%, Al2O3An obstacle occurs in the formation of the film, which adversely affects the toughness of the hot coil, so the upper limit is made 1%.
  Mn is also an inevitable impurity, and if it exceeds 1%, the hot coil toughness deteriorates, so the upper limit is made 1%.
[0031]
  When rare earth elements are added even though P is an inevitable impurity, hot workability is improved by increasing P. On the other hand, if it exceeds 0.05%, the toughness of the hot coil deteriorates, so the upper limit is made 0.05%.
  S is also an inevitable impurity, and if it exceeds 0.01%, the oxidation resistance is adversely affected, so the upper limit is made 0.01%.
[0032]
  In the first and second inventions, the surface roughness of the flat foil and the corrugated foil is 0.001 μm or more and 0.2 μm or less in average roughness (Ra), and the flat foil and the corrugated foil are stacked to form a spiral shape. High-strength bonding is obtained by forming a honeycomb body by wrapping around or alternately laminating and inserting the honeycomb body into an outer cylinder and performing diffusion bonding.
[0033]
  In general, in diffusion bonding, a material to be bonded needs to be in close contact with each other, and a pressurizing device or a weight is used so that a surface pressure is applied to the contact portion even during heating. However, in the case of a metal carrier, it is difficult to apply a surface pressure from the outside due to the peculiarity of the structure, so that the limited tension applied to the flat foil 5 when the honeycomb body is wound as shown in FIG. It is necessary to perform diffusion bonding under the back tension, the relatively small surface pressure obtained by the reduced diameter after the honeycomb body is fitted into the outer cylinder, or the surface pressure applied by the insertion of the intermediate cylinder.
[0034]
  As a result of searching for a method for improving the diffusion bonding property under such a relatively small surface pressure, the present inventors have found that it is effective to reduce the surface roughness of the flat foil and the corrugated foil at the bonding interface. I found out. As a result of the experiment, when the average roughness (Ra) of the flat foil and the corrugated foil was 0.2 μm or less, a good diffusion bonded portion was obtained very easily. And even if Ra was smoothed to less than 0.001 μm, the influence on diffusion bonding was saturated. In addition, it was confirmed that the diffusion bonding property of the honeycomb body and the outer cylinder is similarly improved by setting the surface roughness of the inner surface of the outer cylinder to Ra of 0.001 μm to 0.2 μm. Therefore, in the present invention, the surface roughness is limited as described above.
[0035]
  Such a metal carrier of the first and second inventions can be manufactured by simultaneously joining the contact portion between the flat foil and the corrugated foil and the contact portion between the honeycomb body and the outer cylinder by diffusion bonding, It has sufficient bonding strength. As a diffusion bonding means, a method of heating in a non-oxidizing atmosphere furnace such as a vacuum furnace can be adopted. Conventionally, in a metal carrier made of Fe-Cr-Al ferritic stainless steel, during diffusion bonding, a small amount of oxygen in the heating atmosphere reacts with Al in the steel, and Al2O3In the present invention, each contact portion is in close contact, and as described above, Ti or Nb carbonitrides or the like are formed on the interface of each contact portion. Since the precipitation on the surface is suppressed, Al2O3The problem of poor bonding due to the film does not occur.
[0036]
  Next, in the first and second inventions, an intermediate cylinder made of ferritic stainless steel is inserted between the outer cylinder and the honeycomb body, and the intermediate cylinder is diffusion-bonded to the outer cylinder and the honeycomb body. preferable. As the material of the intermediate cylinder, the above-mentioned Al-added material or Al-free material can be adopted. The intermediate cylinder has a notch 9 as shown in each development example of FIG. 4, and when the intermediate cylinder 8 is fitted between the honeycomb body 1 and the outer cylinder 2 as shown in FIG. It works.
[0037]
  For this reason, the contact surface pressure is increased and the adhesion is improved at each contact portion of the outer cylinder 2 and the intermediate cylinder 8, the intermediate cylinder 8 and the honeycomb body 1, and further the flat foil 5 and the corrugated foil 6 of the honeycomb body 1. Therefore, the metal carriers of the first invention and the second invention obtained by heating this in a non-oxidizing atmosphere and performing diffusion bonding have improved bonding strength.
[0038]
  Furthermore, in the first invention and the second invention, one or both of the Cr content and the Al content is larger in the stainless steel constituting the honeycomb body than the stainless steel constituting the outer cylinder, and the content The difference betweenmass%, Cr is preferably 1.0% or more, and Al is preferably 0.5% or more. In the present invention, in the diffusion bonding between the relatively thick outer cylinder and the honeycomb body made of foil, the above-described difference in the content of the main components of both is promoted, and mutual diffusion is promoted. A metal carrier having a further improved bonding strength can be obtained by diffusion bonding under the same conditions as when there is no difference in components.
[0039]
  When only the Cr content has a difference, a difference of 1.0% or more has a clear effect on the bonding strength, and the higher the difference, the higher the bonding strength. When only the Al content has a difference, a difference of 0.5% or more has a clear effect on the bonding strength as in the case of Cr, and the bonding strength increases as the difference increases. Moreover, when both Cr and Al have a difference, the effect is further improved, but each component difference may be as described above. In addition, the reason why the content of both the Cr and Al is larger in the honeycomb body is that it comes into contact with the high temperature exhaust gas and becomes higher in temperature.
[0040]
  In the first invention and the second invention, when the intermediate cylinder is provided, one or both of the Cr content and the Al content is larger in the stainless steel constituting the intermediate cylinder than in the stainless steel constituting the outer cylinder. And the stainless steel constituting the honeycomb body is larger than the stainless steel constituting the intermediate cylinder, and the difference in the content ismass%, Cr is preferably 1.0% or more, and Al is preferably 0.5% or more. The reasons for limiting the effects and differences between the components are as described above. In addition, for both Cr and Al, the content of stainless steel constituting the honeycomb body is maximized, and the outer cylinder is minimized. The honeycomb body has the highest temperature, then the intermediate cylinder, and then the outer cylinder. Because.
[0041]
  In the above description, the difference between the Cr content and the Al content is preferably large from the viewpoint of promoting diffusion bonding, and the upper limit is not particularly limited. However, as described above, the honeycomb body has a Cr content of 11 to 30% and an Al content of 1 depending on the use environment from the viewpoint of corrosion resistance, oxidation resistance and heat fatigue resistance as a metal carrier, and manufacturability of the material. Since the outer cylinder and the intermediate cylinder have a Cr content of 11 to 30% and an Al content of 0 to 6%, the upper limit of the difference in content is 19% for Cr and Al. Is 6%.
[0042]
  Next,Method for producing metal carrier according to the present inventionIn the production of the metal carrier of the first invention or the second invention, a flat foil and a corrugated foil are overlapped and spirally wound or alternately laminated to form a honeycomb body, and the honeycomb body is fitted into an outer cylinder. The degree of vacuum is 9 × 10-4Diffusion bonding under high vacuum below TorrIt is characterized by. The flat foil and corrugated foil of the honeycomb body are fitted into the outer cylinder in a state where they are not joined, and the contact portions of the outer cylinder and the honeycomb body, and the flat foil and corrugated foil of the honeycomb body are made by heating at a high temperature under the above high vacuum. Diffusion bonding is performed and sufficient bonding strength is obtained. The vacuum degree is 9 × 10 above-4Under low vacuum exceeding Torr, Al2O3A film may be formed and interdiffusion may be hindered. As heating conditions, it can be set as 1250-1300 degreeC and 60-120 minutes.
[0043]
  Also,Production method of the present invention described aboveThe intermediate tube made of ferritic stainless steel is inserted between the honeycomb body and the outer tube, and the degree of vacuum is 9 × 10.-4Diffusion bonding can also be performed under a high vacuum of Torr or less. Also in this case, the flat and corrugated foils of the honeycomb body are not joined, the intermediate cylinder and the outer cylinder are fitted, and the outer cylinder and the intermediate cylinder, the intermediate cylinder and the honeycomb body are heated at a high temperature under the high vacuum. And each contact part of the flat foil and the corrugated foil of the honeycomb body is diffusion-bonded, and sufficient bonding strength is obtained.
[0044]
  further,Production method of the present invention described aboveIn the present invention, one or both of the Cr content and the Al content of the stainless steel constituting the honeycomb body and the outer cylinder or further the intermediate cylinder had the same difference as the preferred embodiments of the first invention and the second invention. Can be. Thereby, the joining strength after diffusion joining becomes stronger.
[0045]
  In the production method of the present invention,As shown in FIG. 6, it is preferable to use a corrugated corrugated foil in which the contact width 14 between the flat foil 5 and corrugated foil 6 is 30 μm or more. By using such a corrugated foil, the contact area between the flat foil and the corrugated foil is increased, and the diffusion bonding property is further improved. In this case, the corrugated foil 6 can be formed in a trapezoidal shape by changing the tooth shape of the gear roll during corrugating.
[0046]
  Also,In the production method of the present invention,An intermediate cylinder made of ferritic stainless steel can be inserted between the honeycomb body and the outer cylinder. Also in this case, the flat and corrugated foils of the honeycomb body are not joined, and the intermediate cylinder and the outer cylinder are fitted, and the outer cylinder and the intermediate cylinder, the intermediate cylinder and the honeycomb body, and the contact between the flat foil and the corrugated foil of the honeycomb body The parts are diffusion-bonded and a sufficient bonding strength is obtained. In addition, by setting the surface roughness of the inner and outer surfaces of the intermediate cylinder to 0.001 μm or more and 0.2 μm or less in Ra, diffusion bonding between the intermediate cylinder, the honeycomb body, and the outer cylinder is further improved.
[0047]
  The metal carrier for catalyst of the first and second inventions of the present invention described above, andManufacturing method described aboveThe catalyst metal carrier produced by the above method forms a heat-resistant porous layer (wash coat layer) such as activated alumina on the surface of the stainless steel foil of the honeycomb body, and supports a catalyst made of a noble metal such as Pt on the layer, It is mounted on the exhaust gas path of the internal combustion engine.
[0048]
【Example】
  [Example 1]
  As an example of the first invention and the second invention, a strip-like flat foil having a thickness of 50 + μm is manufactured from a cold-rolled sheet of each Fe—Cr—Al ferritic stainless steel composed of the components shown in Table 1, and a part of the flat foil is produced. Corrugated to produce corrugated foil. The obtained flat foil and corrugated foil were overlapped and wound as shown in FIG. 2 to form a honeycomb body having a diameter of 80 mm and a length of 120 mm. In addition, a seam welded pipe was manufactured from a 1.5 mm thick cold-rolled sheet having the composition of A in Table 2, and an outer cylinder having an outer diameter of 83 mm, a wall thickness of 1.5 mm, and a length of 120 mm was formed.
[0049]
  The honeycomb body is inserted into the outer cylinder, and charged into a vacuum heating furnace to obtain 3 × 10-4While maintaining the degree of vacuum at Torr, heating and holding were performed at 1250 ° C. for 90 minutes, and the outer cylinder and the outermost periphery of the honeycomb body, and the flat foil and corrugated foil of the honeycomb body were diffusion bonded.
  In order to examine the bonding strength of the diffusion-bonded metal carrier, six disk-shaped test pieces 11 having a thickness of 20 mm were cut out as shown in FIG. Reference numeral 10 denotes a cut surface. Then, as shown in FIG. 7B, the portion of the outer cylinder 2 of the test piece 11 is placed on the cylindrical cradle 13, and the stepped punch 12 is pressed against the portion of the honeycomb body 1 from above, The load (punching load) at the time of breaking was measured.
[0050]
  Table 1 shows the average value of the punching loads for the six test pieces of each metal carrier. The examples of the present invention all have a high punching load and have excellent bonding strength. In addition, if this punching load is 350 kg or more, it has been confirmed that there is no problem with respect to damage when mounted in an actual exhaust gas path and used. Comparative Example No. 25 and No. No. 26 is because No. 1 is not established. 27 and no. In No. 28, since the expression (2) is not established when REM is added, the punching load is low, and the required bonding strength is not obtained.
[0051]
[Table 1]
Figure 0003816974
[0052]
[Table 2]
Figure 0003816974
[0053]
  [Example 2]
  As a preferable example of the first invention, No. 1 in Table 1 is used. 5 and no. For No. 7, a metal carrier having an intermediate cylinder inserted therein was manufactured. The intermediate cylinder has an outer diameter of 81 mm and a wall thickness of 0.5 mm, and has an incision 9 as shown in the developed view of FIG. 4A. The outer cylinder and the honeycomb body having an outer diameter of 84 mm and a wall thickness of 1.5 mm Inserted. The other conditions were the same as in Example 1, and diffusion bonding was performed under the same conditions as in Example 1, and the punching load was measured. As a result, no. 5 is 600 kg. 7 is 620 kg, and the joining strength is improved by the intermediate cylinder. 4B and 4C have the same effect, and the one having the cut as shown in FIG. 4D has a slightly inferior effect.
[0054]
  [Example 3]
  As another preferable example of the first invention and the second invention, five types (No. 4, No. 6, No. 17, No. 21, No. 25) of the honeycomb body materials shown in Table 1 are used. 9 types of metal carriers shown in Table 3 were manufactured by combining 6 types of stainless steels shown in Table 2. The symbols A to D, G, and H in Table 3 were produced under the same conditions as in Example 1, and the symbols E, F, and R were produced under the same conditions as in Example 2. Each stainless steel in Table 2 is a component within the scope of the first invention.
[0055]
  Table 3 shows the punching load of each metal carrier. In the symbol A of the present invention example, the honeycomb body is larger in Al content than the outer cylinder (the outer cylinder is Al-free), and the difference is 0.5% or more, so there is a difference in Cr content. Although it is not, the punching load is higher than the symbol H of the comparative example. The symbols Ro to Ni in the examples of the present invention have a Cr content and an Al content larger in the honeycomb body than in the outer cylinder (both outer cylinders do not contain Al), and the difference is 1.0 for Cr. % Or more, and 0.5% or more of Al, each has a higher punching load than the symbol H of the comparative example.
[0056]
  The symbol “G” in the comparative example is shown in Table 1 No. Since the stainless steel made of 25 is used, and the Cr content of the honeycomb body and the outer cylinder is the same and the Al content is different, the difference is less than 0.5%, so the punching load is low. Since the symbol H in the comparative example satisfies the conditions of the first invention, the punching load is as high as 410 kg. However, since both Cr and Al have no difference in content between the honeycomb body and the outer cylinder, the present invention It is lower than the symbols ii in the example.
[0057]
  Symbols E and F in the example of the present invention have an intermediate cylinder. The symbol H has a Cr content and an Al content that are larger in the intermediate tube than in the outer tube, and in the honeycomb body over the intermediate tube, both of which are 1.0% or more in Cr and Al. Since it is 0.5% or more, the punching load is high. The symbol F has a small difference in Al content between the intermediate cylinder and the outer cylinder of 0.09, but the difference in Cr is 1.0% or more, and the difference between the honeycomb body and the intermediate cylinder is 1.0% or more in Cr. Since Al is 0.5% or more, the punching load is high.
  On the other hand, the symbol “ri” of the comparative example has an intermediate cylinder, but the honeycomb body has Table 1 No. Since stainless steel consisting of 25 is adopted and there is no difference in Cr content and Al content between the intermediate cylinder and the outer cylinder, the punching load is low.
[0058]
[Table 3]
Figure 0003816974
[0059]
[Table 4]
Figure 0003816974
[0060]
  [Example 4]
  As an example of the third invention, the vacuum degree in the diffusion bonding was changed in producing five kinds of metal carriers of symbols A, B, C, D and E shown in Table 3. That is, the honeycomb body to which the foil is not bonded is inserted into the outer cylinder (ii), the intermediate cylinder is fitted between the honeycomb body and the outer cylinder (e), and the honeycomb body is inserted into the vacuum heating furnace. Diffusion bonding was performed. The degree of vacuum in the furnace is 3 × 10-3Torr, 9 × 10-4Torr, 3 × 10-4Torr, 1 × 10-4The four Torr levels and heating conditions were all maintained at 1250 ° C. for 90 minutes.
  As shown in Table 4, the punching load of each metal carrier after the joining was 3 × 10 in the degree of vacuum of the comparative example.-3In Torr, the value was low, but 9 × 10 of the example of the present invention.-4Below Torr, all values were sufficiently high.
[0061]
[Table 5]
Figure 0003816974
[0062]
  [Example 5]
  As an example of the fourth invention, a metal carrier was manufactured by changing the surface roughness of the flat foil and the corrugated foil and changing the contact width between the flat foil and the corrugated foil. Table 1 No. 8 (20Cr-5Al-0.3Nb) composition, 50 μm-thick flat foil and corrugated foil are stacked as shown in FIG. A honeycomb body having an outer diameter of 80 mm and a length of 120 mm was formed.
[0063]
  The surface roughness of the flat foil and corrugated foil before winding is set to five levels of 0.001 μm, 0.01 μm, 0.1 μm, 0.2 μm, and 0.3 μm in average roughness (Ra). The contact widths 14 shown in FIG. 6 of the latter two foils were set to four levels of 20 μm, 30 μm, 50 μm, and 200 μm. The contact width was varied by corrugating a flat foil with a gear roll to form a corrugated foil by changing the tooth shape of the gear roll and forming corrugated foils having different corrugations.
[0064]
  In addition, a seam welded pipe is manufactured from a cold-rolled material having a thickness of 1.5 mm having a composition of A (11Cr-0.1Ti) in Table 2, and an outer cylinder having an outer diameter of 83 mm, a wall thickness of 1.5 mm, and a length of 120 mm is formed. did. Then, the honeycomb body is fitted into the outer cylinder, and charged into a vacuum heating furnace, and 3 × 10-4While maintaining the degree of Torr vacuum, it was heated and held at 1250 ° C. for 90 minutes, and the outer cylinder and the outermost periphery of the honeycomb body, and the flat foil and corrugated foil of the honeycomb body were diffusion bonded.
[0065]
  For each of the obtained metal carriers, a test piece cut and cut at the axis orthogonal surface of the outer cylinder was embedded in the resin, and after polishing the axis orthogonal surface, each contact for 20 layers was observed from the outer periphery of the honeycomb body, The diffusion bonding rate was determined. The diffusion bonding rate is the number of bonding points / the total number of contacts. As shown in Table 5, the diffusion bonding rate was 0.60 or more in a region having a surface roughness of 0.2 μm or less and a contact width of 30 μm or more. And when the metal carrier of this area | region was mounted in the exhaust system of a gasoline engine and the endurance test of 900 cycles of * heating 900 degreeC x 10 minutes + cooling room temperature x10 minutes was implemented, all passed.
[0066]
[Table 6]
Figure 0003816974
[0067]
【The invention's effect】
  In the catalyst metal carrier of the present invention, the flat foil and corrugated foil of the honeycomb body, and the contact portions of the outer cylinder and the honeycomb body are all firmly bonded by diffusion bonding. Conventionally, in the case of diffusion bonding in a metal carrier, since sufficient bonding strength may not be obtained in a range that does not hinder productivity, some brazing bonding has been performed, but according to the present invention, diffusion bonding is performed. Only a strong and stable bonding strength can be obtained. Therefore, by joining the contact portions such as the flat foil and corrugated foil of the honeycomb body and the outermost layer of the honeycomb body and the outer cylinder at the same time by diffusion bonding, the manufacturing process is simplified, and the material cost of the brazing filler metal, etc. Process costs are saved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a structural example of a metal carrier of the present invention.
FIG. 2 is a perspective view showing an example of manufacturing a honeycomb body in the metal carrier of the present invention.
FIG. 3 is a front view showing a structural example of a honeycomb body in the metal carrier of the present invention.
FIG. 4 is a development view showing an example of the structure of an intermediate cylinder in the metal carrier of the present invention.
FIG. 5 is a longitudinally divided perspective view showing an example in which an intermediate cylinder is inserted in the metal carrier of the present invention.
FIG. 6 is a partially enlarged front view showing a contact state between a flat foil and a corrugated foil in the method of the present invention.
FIG. 7 is an explanatory diagram showing a method for measuring the bonding strength in Examples.
[Explanation of symbols]
          1 ... Honeycomb body 2 ... Outer cylinder
          3 ... stainless steel foil 4 ... vent
          5 ... Flat foil 6 ... Wave foil
          7 ... Shaft 8 ... Intermediate tube
          9 ... Incision 10 ... Cut surface
        11 ... Test piece 12 ... Stepped punch
        13 ... cradle 14 ... contact width

Claims (9)

質量%で
C:0.05%以下
Si:1.0%以下
Mn:1.0%以下
Cr:11〜30%
Al:1〜6%
N:0.03%以下
P:0.05%以下
S:0.01%以下
を含有するフェライト系ステンレス鋼からなり、平箔と波箔が重ねて渦巻状に巻回され、または交互に積層されたハニカム体が、外筒に嵌入されて形成されたメタル担体において、前記平箔と波箔の表面粗さを、平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方を含有するとともに、各成分の含有量が(1)式の関係を満足し、
[Nb]+2[Ti]≦8[C]+48/7[N]+3[S]+6[O]+0.1
(1)
ただし、[Nb]、[Ti]、[C]、[N]、[S]、[O]は、それぞれNb、Ti、C、N、S、Oの含有量(質量%)
かつ、前記平箔、波箔、および外筒の各接触部が拡散接合により接合されていることを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体。
By mass % C: 0.05% or less Si: 1.0% or less Mn: 1.0% or less Cr: 11-30%
Al: 1-6%
N: 0.03% or less P: 0.05% or less S: Made of ferritic stainless steel containing 0.01% or less, flat foil and corrugated foil are wound in a spiral shape or laminated alternately In the metal carrier formed by inserting the honeycomb body into the outer cylinder, the surface roughness of the flat foil and the corrugated foil is 0.001 μm or more and 0.2 μm or less in terms of average roughness (Ra), The stainless steel contains one or both of Ti: 0.02-0.3% and Nb: 0.04-0.4% in mass %, and the content of each component is represented by the formula (1) Satisfied with the relationship
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +3 [S] +6 [O] +0.1
(1)
However, [Nb], [Ti], [C], [N], [S], and [O] are the contents ( mass %) of Nb, Ti, C, N, S, and O, respectively.
A diffusion-bonded catalyst metal carrier having strong bonding strength, wherein the contact portions of the flat foil, corrugated foil, and outer cylinder are bonded by diffusion bonding.
質量%で
C:0.05%以下
Si:1.0%以下
Mn:1.0%以下
Cr:11〜30%
Al:1〜6%
N:0.03%以下
P:0.05%以下
S:0.01%以下
を含有するフェライト系ステンレス鋼からなり、平箔と波箔が重ねて渦巻状に巻回され、または交互に積層されたハニカム体が、外筒に嵌入されて形成されたメタル担体において、前記平箔と波箔の表面粗さを、平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方、およびYを含む希土類元素の合計:0.005〜0.2%を含有するとともに、各成分の含有量が(2)式の関係を満足し、
[Nb]+2[Ti]≦8[C]+48/7[N]+0.1 (2)
ただし、[Nb]、[Ti]、[C]、[N]は、それぞれNb、Ti、C、Nの含有量(質量%)
かつ、前記平箔、波箔、および外筒の各接触部が拡散接合により接合されていることを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体。
By mass % C: 0.05% or less Si: 1.0% or less Mn: 1.0% or less Cr: 11-30%
Al: 1-6%
N: 0.03% or less P: 0.05% or less S: Made of ferritic stainless steel containing 0.01% or less, flat foil and corrugated foil are wound in a spiral shape or laminated alternately In the metal carrier formed by inserting the honeycomb body into the outer cylinder, the surface roughness of the flat foil and the corrugated foil is 0.001 μm or more and 0.2 μm or less in terms of average roughness (Ra), The total amount of rare earth elements including one or both of Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4% and Y: 0.005 to 0 by mass %. .2% and the content of each component satisfies the relationship of formula (2),
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +0.1 (2)
However, [Nb], [Ti], [C], and [N] are the contents ( mass %) of Nb, Ti, C, and N, respectively.
A diffusion-bonded catalyst metal carrier having strong bonding strength, wherein the contact portions of the flat foil, corrugated foil, and outer cylinder are bonded by diffusion bonding.
外筒とハニカム体の間に、フェライト系ステンレス鋼からなる中間筒が嵌入され、該中間筒が外筒およびハニカム体と拡散接合されていることを特徴とする請求項1または2記載の強固な接合強度を有する拡散接合された触媒用メタル担体。  3. The solid cylinder according to claim 1, wherein an intermediate cylinder made of ferritic stainless steel is inserted between the outer cylinder and the honeycomb body, and the intermediate cylinder is diffusion bonded to the outer cylinder and the honeycomb body. A diffusion-bonded catalyst metal carrier having bonding strength. Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることを特徴とする請求項1または2記載の強固な接合強度を有する拡散接合された触媒用メタル担体。One or both of the Cr content and the Al content is larger in the stainless steel constituting the honeycomb body than the stainless steel constituting the outer cylinder, and the difference in the content is about% by mass in terms of Cr. The metal carrier for diffusion-bonded catalyst according to claim 1 or 2, characterized in that is 1.0% or more and Al is 0.5% or more. Cr含有量とAl含有量の一方または双方が、外筒を構成するステンレス鋼よりも中間筒を構成するステンレス鋼の方が大であり、かつ中間筒を構成するステンレス鋼よりもハニカム体を構成するステンレス鋼の方が大であり、該各含有量の差は、質量%にて、Crについては1.0%以上、Alについては0.5%以上であることを特徴とする請求項3記載の強固な接合強度を有する拡散接合された触媒用メタル担体。  One or both of Cr content and Al content is larger in stainless steel constituting the intermediate cylinder than stainless steel constituting the outer cylinder, and constitutes a honeycomb body than stainless steel constituting the intermediate cylinder The stainless steel to be processed is larger, and the difference in each content is, in mass%, 1.0% or more for Cr and 0.5% or more for Al. A diffusion-bonded metal carrier for catalyst having the above-described strong bonding strength. 請求項1または2記載のメタル担体の製造に際し、平箔と波箔を重ねて渦巻状に巻回し、または交互に積層してハニカム体を形成し、該ハニカム体を外筒に嵌入し、真空度9×10−4Torr以下の高真空下で拡散接合することを特徴とする強固な接合強度を有する拡散接合された触媒用メタル担体の製造方法。In producing the metal carrier according to claim 1 or 2, a flat foil and a corrugated foil are overlapped and spirally wound, or alternately laminated to form a honeycomb body, and the honeycomb body is fitted into an outer cylinder, and a vacuum is formed. A method for producing a diffusion-bonded catalyst metal carrier having strong bonding strength, characterized by diffusion bonding under a high vacuum of a degree of 9 × 10 −4 Torr or less. 平箔と波箔の接触幅が30μm以上となる波形状の波箔を用いることを特徴とする請求項6記載の強固な接合強度を有する拡散接合された触媒用メタル担体の製造方法。  7. The method for producing a diffusion-bonded catalyst metal carrier having strong bonding strength according to claim 6, wherein a corrugated corrugated foil having a contact width of 30 μm or more between the flat foil and corrugated foil is used. 質量%で
C:0.05%以下
Si:1.0%以下
Mn:1.0%以下
Cr:11〜30%
Al:1〜6%
N:0.03%以下
P:0.05%以下
S:0.01%以下
を含有するフェライト系ステンレス鋼箔であって、その平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方を含有するとともに、各成分の含有量が下記(1)式、
[Nb]+2[Ti]≦8[C]+48/7[N]+3[S]+6[O]+0.1
(1)
ただし、[Nb]、[Ti]、[C]、[N]、[S]、[O]は、それぞれNb、Ti、C、N、S、Oの含有量(質量%)
の関係を満足することを特徴とする拡散接合用のメタル担体用箔。
By mass % C: 0.05% or less Si: 1.0% or less Mn: 1.0% or less Cr: 11-30%
Al: 1-6%
N: 0.03% or less P: 0.05% or less S: Ferritic stainless steel foil containing 0.01% or less, and an average roughness (Ra) of 0.001 μm to 0.2 μm. while, the stainless steel is at mass% Ti: 0.02 to 0.3% and Nb: with containing one or both of 0.04 to 0.4%, the content of each component below (1) Formula,
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +3 [S] +6 [O] +0.1
(1)
However, [Nb], [Ti], [C], [N], [S], and [O] are the contents ( mass %) of Nb, Ti, C, N, S, and O, respectively.
A metal carrier foil for diffusion bonding characterized by satisfying the following relationship:
質量%で
C:0.05%以下
Si:1.0%以下
Mn:1.0%以下
Cr:11〜30%
Al:1〜6%
N:0.03%以下
P:0.05%以下
S:0.01%以下
を含有するフェライト系ステンレス鋼箔であって、その平均粗さ(Ra)で0.001μm以上0.2μm以下とすると共に、前記ステンレス鋼が、質量%にて、Ti:0.02〜0.3%とNb:0.04〜0.4%の一方または双方、およびYを含む希土類元素の合計:0.005〜0.2%を含有するとともに、各成分の含有量が下記(2)式、
[Nb]+2[Ti]≦8[C]+48/7[N]+0.1 (2)
ただし、[Nb]、[Ti]、[C]、[N]は、それぞれNb、Ti、C、Nの含有量(質量%)
の関係を満足することを特徴とする拡散接合用のメタル担体用箔。
By mass % C: 0.05% or less Si: 1.0% or less Mn: 1.0% or less Cr: 11-30%
Al: 1-6%
N: 0.03% or less P: 0.05% or less S: Ferritic stainless steel foil containing 0.01% or less, and an average roughness (Ra) of 0.001 μm to 0.2 μm. In addition, the total amount of rare earth elements including one or both of Ti: 0.02 to 0.3% and Nb: 0.04 to 0.4% and Y in terms of mass % : 005 to 0.2%, and the content of each component is the following formula (2) :
[Nb] +2 [Ti] ≦ 8 [C] +48/7 [N] +0.1 (2)
However, [Nb], [Ti], [C], and [N] are the contents (mass%) of Nb, Ti, C, and N, respectively.
A metal carrier foil for diffusion bonding characterized by satisfying the following relationship:
JP25801495A 1995-10-04 1995-10-04 Diffusion bonded metal carrier for catalyst having strong bonding strength and method for producing the same Expired - Fee Related JP3816974B2 (en)

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TW365548B (en) 1997-05-09 1999-08-01 Nippon Steel Corp Metallic honeycomb body for supporting catalyst for purifying exhaust gas and process for producing the same
JP3720973B2 (en) 1998-03-16 2005-11-30 新日本製鐵株式会社 Diffusion bonded metal carrier and manufacturing method thereof
JP3350499B2 (en) * 2000-01-20 2002-11-25 新日本製鐵株式会社 Rough surface finish metal foil with good corrugation and catalyst carrier for exhaust gas purification
JP2008279410A (en) * 2007-05-14 2008-11-20 Calsonic Kansei Corp Method for manufacturing metallic catalyst carrier
KR101132702B1 (en) * 2009-12-22 2012-04-02 한국기계연구원 A Poromeric sandwich panel and method of manufacturing the same
JP5868241B2 (en) * 2012-03-29 2016-02-24 日新製鋼株式会社 Ferritic stainless steel for diffusion bonding and method for manufacturing diffusion bonding products
US9987706B2 (en) 2013-05-15 2018-06-05 Nisshin Steel Co., Ltd. Method for producing a stainless steel diffusion-bonded product
JP6129140B2 (en) 2014-11-05 2017-05-17 日新製鋼株式会社 Stainless steel for diffusion bonding

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JPH0214747A (en) * 1988-06-30 1990-01-18 Aichi Steel Works Ltd Production of metallic honeycomb carrier
JP2794200B2 (en) * 1989-07-18 1998-09-03 日本金属株式会社 Manufacturing method of metal catalyst support
JPH0822380B2 (en) * 1989-10-02 1996-03-06 トヨタ自動車株式会社 Method for manufacturing carrier for exhaust gas purification catalyst
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JP3482249B2 (en) * 1994-08-01 2003-12-22 新日本製鐵株式会社 Method for producing metal carrier and metal foil made of heat-resistant alloy with good diffusion bonding property
JPH08112532A (en) * 1994-10-14 1996-05-07 Nippon Steel Corp Metallic substrate for exhaust gas purification catalyst and its production

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