JPH048502B2 - - Google Patents
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- Publication number
- JPH048502B2 JPH048502B2 JP61218776A JP21877686A JPH048502B2 JP H048502 B2 JPH048502 B2 JP H048502B2 JP 61218776 A JP61218776 A JP 61218776A JP 21877686 A JP21877686 A JP 21877686A JP H048502 B2 JPH048502 B2 JP H048502B2
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- 229910052779 Neodymium Inorganic materials 0.000 claims description 12
- 229910002060 Fe-Cr-Al alloy Inorganic materials 0.000 claims description 10
- 229910052746 lanthanum Inorganic materials 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims 3
- 230000003647 oxidation Effects 0.000 description 29
- 238000007254 oxidation reaction Methods 0.000 description 29
- 239000011888 foil Substances 0.000 description 11
- 229910052761 rare earth metal Inorganic materials 0.000 description 11
- 229910045601 alloy Inorganic materials 0.000 description 10
- 239000000956 alloy Substances 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000005098 hot rolling Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 230000007704 transition Effects 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 229910052747 lanthanoid Inorganic materials 0.000 description 4
- 150000002602 lanthanoids Chemical class 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000007792 addition Methods 0.000 description 3
- 238000005097 cold rolling Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910018138 Al-Y Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000004299 exfoliation Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 230000004584 weight gain Effects 0.000 description 1
- 235000019786 weight gain Nutrition 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Description
〔産業上の利用分野〕
本発明は、酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金に関し、高温酸化性雰囲気下
で激しい繰返し酸化を受ける自動車排ガス浄化用
触媒コンバータに好適なほか、燃焼ガス排気系の
機器、装置、暖房機部品などにも有用である。
〔従来の技術〕
従来、自動車排ガス浄化用触媒コンバータに
は、コーデイエライト（2MgO・2Al2O3・
5SiO2）の押出焼成ハニカムにγ−アルミナ微粒
子を触媒担体としてコーテイングした後、Ptな
どの触媒をつけたものが用いられている。
特開昭56−96726号公報に示されているように、
このコーデイエライト製ハニカムを耐酸化ステン
レス箔を組みたてて製作した金属製ハニカムにす
ると、コンバータの小型化、エンジン性能の向上
など、種々の利点がある。前記引用公報では耐酸
化ステンレス箔としてイツトリウム（Ｙ）を添加
したFe−Cr−Al系合金（Cr：15〜25重量％、
Al：３〜６重量％、Ｙ：0.3〜1.0重量％）を提案
しているが、Ｙが希少金属であるため非常に高価
となり、かつ供給量にも不安があり、一般の自動
車に用いるのは経済性の点で困難であつた。
これに対し、特開昭58−177437号公報では
Cr：８〜25重量％、Al：３〜８重量％、全希土
類元素が0.06重量％までで、0.002〜0.05重量％の
Ce、La、Ndなどを添加した合金（以下これを
Fe−Cr−Al−REM合金と呼ぶ）の使用を提案し
ている。これは希土類元素の添加によつてスケー
ルの剥離を防いだFe−Cr−Al系合金で、電熱線
などには古くから用いられていたものである。
このようなFe−Cr−Al−REM系合金では一般
用途では十分な酸化スケールの耐剥離性を持つて
いるが、自動車の排気ガス浄化用触媒コンバータ
のように発進、加速、停止のたびに過酷な高温繰
返し酸化と激しい振動を受ける場合、酸化スケー
ルが剥離してしまう。
また、箔であるから、厚さが薄いため、さら
に、このような箔の上に触媒をコーテイングした
構造であるから、酸化スケールが剥離すると排ガ
ス浄化能力の低下を招くこととなる。
REM添加によりスケールの剥離を防止したFe
−Cr−Al−REM合金ではＹ以外の希土類元素は
熱間加工性を低下させるため0.05重量％以上の添
加は不可能としている。
〔発明が解決しようとする問題点〕
本発明は上記事情に鑑み、高温繰返し酸化を受
け激しい振動環境下において酸化スケールの耐剥
離性の極めて高い材料につき研究の結果新知見を
得、この知見に基づいて本発明を完成し、このよ
うな材料を提供することを目的とするものであ
る。
前述の特開昭58−177437では「全希土類の合計
が0.06重量％である少なくとも0.002％そして0.05
％までのセリウムおよびランタン、ネオジムおよ
びプラセオジムよりなる群からの添加物」とし
て、Ceを必須とし、La，Nd等を区別していな
い。
しかし、本発明者らの研究によると、上述の希
土類元素添加による欠点は主にCeが原因であり、
Laのみを0.05重量％を超えて添加すると熱間加工
中の割れを発生することなく圧延加工が可能であ
り、かつ耐酸化性、酸化スケールの耐剥離性を大
幅に向上することを新たに知見した。
〔問題点を解決するための手段〕
そこで本発明はCeを除き、Laを含む材料とし
て、
Ｃ：0.02重量％以下
Si：1.5重量％以下
Cr：13重量％以上27重量％以下
Al：3.5重量％以上８重量％以下
La：0.05重量％を超え、0.20重量％以下
を含み、残分がFeと不可避不純物よりなること
を特徴とする酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金が上記問題点を解決する本発
明の材料である。
次に本発明の第２発明は上記材料にTiをＣ重
量％の５倍以上0.10重量％以下を含む酸化スケー
ルの耐剥離性に優れたFe−Cr−Al系合金である。
さらに本発明の第３の発明は、第１の発明にお
いて、Laが0.20重量％未満で、Ndが0.001重量％
以上0.03重量％未満を含む酸化スケールの耐剥離
性に優れたFe−Cr−Al系合金である。
また本発明の第４の発明は、上記第３の発明
に、TiをＣ重量％の５倍以上の0.10重量％以下を
含む酸化スケールの耐剥離性に優れたFe−Cr−
Al系合金である。
〔作用〕
本発明合金は各成分の含有量によつて、耐酸化
性及び酸化スケールの剥離性が極めて高くなる作
用を有し、特にCeを積極的に除外したランタノ
イドを利用したものである。以下各成分の限定理
由を述べる。
La：
0.05重量％以下では厚さ50μm程度の箔での
耐酸化性及び酸化スケールの耐剥離性を確保で
きず、0.20重量％を超えると熱間圧延が不可能
になるので0.05重量％を超えて0.20重量％以下
とした。
Nd：
Ceを除くランタノイドは、耐酸化性及び酸
化スケールの耐剥離性向上に対しLaと同様な
効果があり特にNdはLaに次いでその効果が大
きい。また、原鉱石からLaを精製する場合、
純粋なLaより、Ndを含有した形態の方が容易
な場合がある。Ndは、0.001重量％未満では、
耐酸化性の向上効果がなく、特に、0.03重量％
以上では加工性が低下するので、範囲を0.001
重量％以上0.03重量％未満とする。しかしラン
タノイドが多すぎると熱間圧延が不可となるの
でLaとNdの合計は0.20重量％以下とする。
Cr：
13重量％未満では耐酸化性が確保できず、27
重量％を超えると靭性が低下し、冷間加工が困
難となるので13〜27重量％とした。
Al：
3.5重量％未満では耐酸化性が確保できず、
８重量％を超えると熱間圧延が困難となるので
3.5〜８重量％とした。
Si：
耐酸化性向上に有効であるが1.5重量％を超
えると加工性を低下させるので1.5重量％以下
とした。
Ｃ：
過剰になると靭性を低下させ、冷間圧延性、
加工性を悪化させるので0.02重量％以下にする
必要がある。
Ti：以上のほかにさらにTiを添加するとTi
が炭化物となつてＣを固定して靭性を改善す
る。TiはＣ濃度の５倍以上添加しないとその
改善効果が表れないが、0.1重量％を超えて添
加すると耐酸化性を低下させるので、Ｃ重量％
の５倍〜0.10重量％とする。
また、これらの主要元素のほかに、希土類金属
であるLa，Ndの純度の関係から不可避的に混入
する希土類元素例えばLa，Ndを除くランタノイ
ドを含有してもよい。
〔実施例〕
第１表に本発明の実施例の合金の化学成分を示
し、第２表に比較例の合金の化学成分を示す。
実施例および比較例はそれぞれ10Kgインゴツト
に溶製造塊した後、1200℃で板厚３mmまで熱間圧
延した。この段階でREM濃度が0.058重量％のＢ
−３、La濃度が0.22重量％のＢ−４、Ce濃度が
0.085重量％のＢ−６、Al濃度が8.2重量％のＢ−
10は熱間圧延時に鋼塊が割れたので、その後の試
験は行つていない。
実施例および比較例の上記Ｂ−３、４、６、12
を除く比較例は、次に900℃で焼純した後シヤル
ピー試験を行ない靭性を調べた。その結果の一部
を第１図に示す。Ｃ濃度が0.001重量％と低いＡ
−１やＣ濃度は0.016重量％と高いがTiを0.09重
量％添加したＡ−３は延性・脆性遷移温度が50〜
70℃と良好な靭性があり、冷間圧延が容易であつ
た。これに対してＣが0.022重量％と高いＢ−８
は遷移温度が130℃と靭性が悪く冷間圧延が困難
であり温間圧延で行う必要があつた。同様にCr
が27.2重量％のＢ−11とSiが1.8重量％のＢ−14も
遷移温度が100℃を超え冷間圧延が困難であつた。
その後、脱スケール、冷間圧延（Ｂ−８、Ｂ−
11、Ｂ−14は温間圧延）、焼純を繰返し板厚50μm
の箔にした。これから板厚50μm、幅20mm、長さ
30mmの試験片を採取して、1150℃大気中雰囲気で
酸化試験を行つた。
その結果の一部を第２図に示す。Tiが0.21重量
％と高いＢ−９、Ceが0.062重量％のＢ−７は100
〜120時間で完全に酸化して原形を留めていない。
同様にAlが3.2重量％のＢ−12、Crが12.5重量％
のＢ−13も耐酸化性が不十分であつた。それに対
し実施例Ａ−２は高価なFe−Cr−Al−Ｙ合金で
あるＢ−１に匹敵する良好な耐酸化性を示し、
200時間後も酸化増量が1.1mg／m2と非常に良好な
耐酸化性を示している。この様にCeは耐酸化性
を低下させるが、La、NdはＹと同様に耐酸化性
を大幅に向上させている。
最後に同一形状の試験片を1150℃大気中雰囲気
で30分間酸化させた後、12分間急冷するのを１回
として、200回の繰返し酸化を行つた後、電子顕
微鏡で酸化スケールの検査とした。例として実施
例Ａ−２の結果を第３図に、比較例Ｂ−２の結果
を第４図に示す。実施例Ａ−２では酸化スケール
の剥離は全く見られないが、比較例Ｂ−２では半
分程度の酸化スケールが剥離している。
Laが0.03重量％のＢ−５、Crが低い比較例Ｂ
−13も同様な剥離が観察された。
以上の結果を総合して第１表、第２表中に合わ
せて評価したが、本発明の範囲にある第１表の
Fe−Cr−Al−La（−Ti）合金は製造性および特
性の両方において優れていることは明白である。
La、Ndは熱間加工性をほとんど低下させず、
耐酸化性、耐剥離性を大幅に向上させるが、、Ce
は熱間加工性、耐酸化性を大幅に低下させること
が明白である。
なお、第１表、第２表中における評価の区分は
以下の基準による。
熱間圧延性：
〇：1200℃加熱後、熱間圧延可能であつたも
の。
×：1200℃加熱後、熱間圧延不可能であつたも
の。
靭 性：
〇：熱延焼鈍板での脆性−延性遷移温度が100
℃未満のもの。
×：熱延焼鈍板での脆性−延性遷移温度が100
℃以上のもの。
耐酸化性：
〇：50μm厚の箔で1150℃×144時間大気中加熱
後の重量増加が1.5mg／cm2未満。
×：50μm厚の箔で1150℃×144時間大気中加熱
後の重量増加が1.5mg／cm2以上。
耐剥離性：
〇：50μm厚の箔で1150℃大気中30分間加熱後
12分間急冷を１回として200回繰返した後
酸化スケールの剥離がないもの。
×：50μm厚の箔で1150℃大気中30分間加熱後
12分間急冷を１回として200回繰返したと
き酸化スケールの剥離があるもの。
また、前述の特開昭56−96726号公報では特殊
な熱処理で表面に長さ数μmのAl2O3ウイスカー
を生成した上に、触媒のコーテイングを行つてい
る。本発明鋼もこれと同一の熱処理を行つた場
合、良好なAl2O3ウイスカーが生成するので、こ
の製造方法による触媒コンバータにも好適であ
る。
[Industrial Application Field] The present invention provides a method for producing oxidized scale with excellent peeling resistance.
Concerning Fe-Cr-Al alloys, they are suitable for catalytic converters for automobile exhaust gas purification, which are subject to intense repeated oxidation in high-temperature oxidizing atmospheres, and are also useful for combustion gas exhaust system equipment, equipment, heater parts, etc. [Conventional technology] Conventionally, cordierite (2MgO, 2Al 2 O 3 ,
5SiO 2 ) extruded fired honeycomb is coated with γ-alumina fine particles as a catalyst carrier, and then a catalyst such as Pt is attached. As shown in Japanese Patent Application Laid-Open No. 56-96726,
If this cordierite honeycomb is made into a metal honeycomb made by assembling oxidation-resistant stainless steel foil, there are various advantages such as miniaturization of the converter and improvement of engine performance. The cited publication describes a Fe-Cr-Al alloy containing yttrium (Y) (Cr: 15 to 25% by weight,
Al: 3-6% by weight, Y: 0.3-1.0% by weight. was difficult from an economic point of view. On the other hand, in Japanese Patent Application Laid-Open No. 58-177437,
Cr: 8-25% by weight, Al: 3-8% by weight, total rare earth elements up to 0.06% by weight, 0.002-0.05% by weight
Alloys with additions of Ce, La, Nd, etc. (hereinafter referred to as
We propose the use of Fe-Cr-Al-REM alloy). This is an Fe-Cr-Al alloy that prevents scale exfoliation by adding rare earth elements, and has been used for a long time in heating wires. Such Fe-Cr-Al-REM alloys have sufficient oxidation scale peeling resistance for general purposes, but they are subject to harsh conditions every time they start, accelerate, and stop, such as in catalytic converters for automobile exhaust gas purification. When exposed to repeated high-temperature oxidation and severe vibration, the oxide scale will peel off. Furthermore, since it is a foil, it is thin, and since the catalyst is coated on the foil, if the oxide scale peels off, the exhaust gas purification ability will be reduced. Fe with scale peeling prevented by REM addition
In the -Cr-Al-REM alloy, it is impossible to add rare earth elements other than Y in an amount of 0.05% by weight or more because they reduce hot workability. [Problems to be Solved by the Invention] In view of the above circumstances, the present invention has obtained new findings as a result of research into materials that have extremely high peeling resistance of oxide scales under intense vibration environments that undergo repeated oxidation at high temperatures, and based on this knowledge. It is an object of the present invention to complete the present invention based on the above, and to provide such a material. The above-mentioned Japanese Patent Publication No. 58-177437 states that "the sum of all rare earths is 0.06% by weight, at least 0.002% and 0.05% by weight".
% of cerium and additives from the group consisting of lanthanum, neodymium and praseodymium, with Ce being essential and La, Nd, etc. not being differentiated. However, according to the research conducted by the present inventors, the drawbacks due to the addition of rare earth elements mentioned above are mainly caused by Ce.
New findings have revealed that adding more than 0.05% by weight of La alone enables rolling processing without cracking during hot working, and significantly improves oxidation resistance and peeling resistance of oxide scale. did. [Means for solving the problem] Therefore, the present invention excludes Ce and uses materials containing La: C: 0.02% by weight or less Si: 1.5% by weight or less Cr: 13% by weight or more and 27% by weight or less Al: 3.5% by weight % or more and 8 wt% or less
Fe-Cr-Al alloy is the material of the present invention that solves the above problems. Next, the second invention of the present invention is an Fe-Cr-Al alloy having excellent peeling resistance of oxide scale, which contains Ti in the above-mentioned material in an amount of not less than 5 times as much as that of C and not more than 0.10% by weight. Furthermore, the third invention of the present invention is the first invention, wherein La is less than 0.20% by weight and Nd is 0.001% by weight.
It is an Fe-Cr-Al alloy that has excellent peeling resistance of oxide scale containing less than 0.03% by weight. Further, the fourth invention of the present invention is a Fe-Cr-1000 having excellent peeling resistance of oxide scale containing Ti in an amount of 0.10% by weight or more, which is 5 times as much as the C weight%, in addition to the third invention.
It is an Al-based alloy. [Function] The alloy of the present invention has the effect of extremely high oxidation resistance and oxidized scale removability depending on the content of each component, and in particular utilizes lanthanoids from which Ce is actively excluded. The reasons for limiting each component will be described below. La: If it is less than 0.05% by weight, oxidation resistance and peeling resistance of oxide scale cannot be ensured in a foil with a thickness of about 50 μm, and if it exceeds 0.20% by weight, hot rolling becomes impossible, so if it exceeds 0.05% by weight. The content was set to 0.20% by weight or less. Nd: Lanthanoids other than Ce have the same effect as La on improving oxidation resistance and peeling resistance of oxide scale, and in particular, Nd has the second largest effect after La. In addition, when refining La from raw ore,
It may be easier to use Nd-containing forms than pure La. If Nd is less than 0.001% by weight,
No effect on improving oxidation resistance, especially 0.03% by weight
If the value is more than 0.001, the workability will decrease.
% by weight or more and less than 0.03% by weight. However, if there is too much lanthanoid, hot rolling becomes impossible, so the total content of La and Nd is set to 0.20% by weight or less. Cr: If it is less than 13% by weight, oxidation resistance cannot be ensured, and 27
If it exceeds 13% to 27% by weight, the toughness decreases and cold working becomes difficult. Al: If it is less than 3.5% by weight, oxidation resistance cannot be ensured,
If it exceeds 8% by weight, hot rolling becomes difficult.
The content was 3.5 to 8% by weight. Si: Effective for improving oxidation resistance, but if it exceeds 1.5% by weight, processability will be reduced, so the content was set to 1.5% by weight or less. C: If it is excessive, it will reduce toughness and reduce cold rollability.
Since it deteriorates processability, it needs to be kept at 0.02% by weight or less. Ti: If Ti is added in addition to the above, Ti
turns into carbide and fixes C, improving toughness. The improvement effect of Ti does not appear unless it is added at least 5 times the C concentration, but if it is added in excess of 0.1% by weight, the oxidation resistance decreases, so the C weight%
5 times to 0.10% by weight. In addition to these main elements, it may contain rare earth elements such as lanthanoids other than La and Nd, which are unavoidably mixed due to the purity of the rare earth metals La and Nd. [Example] Table 1 shows the chemical components of alloys of Examples of the present invention, and Table 2 shows chemical components of alloys of Comparative Examples. In the examples and comparative examples, each ingot was made into a 10 kg ingot and then hot rolled at 1200°C to a thickness of 3 mm. At this stage, B with a REM concentration of 0.058% by weight
-3, B-4 with La concentration of 0.22% by weight, Ce concentration
B-6 with an Al concentration of 0.085% by weight and B- with an Al concentration of 8.2% by weight.
In No. 10, the steel ingot cracked during hot rolling, so no further tests were conducted. Above B-3, 4, 6, 12 of Examples and Comparative Examples
Comparative examples other than were then sintered at 900°C and then subjected to a Charpy test to examine their toughness. A part of the results are shown in FIG. A with a low C concentration of 0.001% by weight
-1 and C concentration are high at 0.016 wt%, but A-3 with 0.09 wt% Ti added has a ductile-brittle transition temperature of 50~
It had good toughness at 70°C and was easy to cold-roll. On the other hand, B-8 has a high C content of 0.022% by weight.
had a transition temperature of 130°C, which made cold rolling difficult and required warm rolling. Similarly Cr
B-11 containing 27.2% by weight of Si and B-14 containing 1.8% by weight of Si also had transition temperatures exceeding 100°C and were difficult to cold-roll. After that, descaling and cold rolling (B-8, B-
11, B-14 is warm rolled) and sintered repeatedly to make the plate thickness 50μm
I made it into a foil. From now on, the plate thickness is 50μm, width is 20mm, and length is
A 30 mm test piece was taken and an oxidation test was conducted at 1150°C in the air. A part of the results are shown in FIG. B-9 has a high Ti content of 0.21% by weight, and B-7 has a Ce content of 0.062% by weight.
It completely oxidizes in ~120 hours and does not retain its original shape.
Similarly, B-12 contains 3.2% by weight of Al and 12.5% by weight of Cr.
B-13 also had insufficient oxidation resistance. On the other hand, Example A-2 showed good oxidation resistance comparable to B-1, which is an expensive Fe-Cr-Al-Y alloy,
Even after 200 hours, the oxidation weight gain was 1.1 mg/m 2 , showing very good oxidation resistance. In this way, Ce reduces oxidation resistance, but La and Nd, like Y, significantly improve oxidation resistance. Finally, a test piece of the same shape was oxidized for 30 minutes at 1150℃ in the air, and then oxidized 200 times, each time being rapidly cooled for 12 minutes, and then examined for oxide scale using an electron microscope. . As examples, the results of Example A-2 are shown in FIG. 3, and the results of Comparative Example B-2 are shown in FIG. In Example A-2, no peeling of oxide scale was observed, but in Comparative Example B-2, about half of the oxide scale had peeled off. B-5 with 0.03% by weight of La, comparative example B with low Cr
Similar peeling was observed for -13. The above results were evaluated by combining them in Tables 1 and 2, and the results of Table 1, which are within the scope of the present invention, were evaluated.
It is clear that the Fe-Cr-Al-La(-Ti) alloy is superior in both manufacturability and properties. La and Nd hardly reduce hot workability,
Although it greatly improves oxidation resistance and peeling resistance, Ce
It is clear that hot workability and oxidation resistance are significantly reduced. The classification of evaluation in Tables 1 and 2 is based on the following criteria. Hot rolling properties: 〇: Hot rolling was possible after heating to 1200°C. ×: After heating to 1200°C, hot rolling was not possible. Toughness: 〇: Brittle-ductile transition temperature of hot rolled annealed plate is 100
Anything below ℃. ×: Brittle-ductile transition temperature of hot rolled annealed plate is 100
Anything over ℃. Oxidation resistance: 〇: Weight increase is less than 1.5 mg/cm 2 after heating in air at 1150°C for 144 hours with 50 μm thick foil. ×: Weight increase of 1.5 mg/cm 2 or more after heating 50 μm thick foil in air at 1150°C for 144 hours. Peeling resistance: 〇: After heating with 50μm thick foil in air at 1150℃ for 30 minutes
No peeling of oxide scale after 12 minute rapid cooling is repeated 200 times. ×: After heating with 50μm thick foil at 1150℃ in air for 30 minutes
Oxidized scale peels off after 200 12-minute quenching cycles. Furthermore, in the above-mentioned Japanese Patent Application Laid-Open No. 56-96726, Al 2 O 3 whiskers several μm in length are formed on the surface by a special heat treatment, and then a catalyst is coated. When the steel of the present invention is subjected to the same heat treatment, good Al 2 O 3 whiskers are produced, so it is also suitable for catalytic converters produced by this manufacturing method.
【表】【table】
以上の実験結果が示すように、本発明鋼は熱間
圧延性、冷間圧延性、耐酸化性、酸化スケールの
耐剥離性に優れており、かつ安価であることから
自動車の触媒コンバータ用ステンレス箔に最適で
あり、自動車の公害対策上におけるメリツトは大
きい。また他の過酷な繰返し酸化を受ける用途に
も有用である。
As shown by the above experimental results, the steel of the present invention has excellent hot rolling properties, cold rolling properties, oxidation resistance, and peeling resistance of oxide scale, and is inexpensive, so it is suitable for use as a stainless steel for automotive catalytic converters. It is ideal for foil, and has great merits in terms of measures against automobile pollution. It is also useful in other applications that undergo severe repeated oxidation.
第１図は焼鈍後の熱延板のシヤルピー試験結果
を示すグラフ、第２図は厚さ50μmの箔での酸化
試験結果を示すグラフ、第３図は実施例の繰返し
酸化後の表面電子顕微鏡写真、第４図は比較例の
繰返し酸化後の表面電子顕微鏡写真である。
Figure 1 is a graph showing the results of a shear py test on a hot-rolled sheet after annealing, Figure 2 is a graph showing the results of an oxidation test on a foil with a thickness of 50 μm, and Figure 3 is a graph showing the surface electron microscopy after repeated oxidation in the example. The photograph and FIG. 4 are electron micrographs of the surface of the comparative example after repeated oxidation.
Claims (1)
を特徴とする酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金。 ２ Ｃ：0.02重量％以下 Si：1.5重量％以下 Cr：13重量％以上27重量％以下 Al：3.5重量％以上８重量％以下 La：0.05重量％を超え、0.20重量％以下 Ti：Ｃ重量％の５倍以上0.10重量％以下 を含み、残分がFeと不可避不純物よりなること
を特徴とする酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金。 ３ Ｃ：0.02重量％以下 Si：1.5重量％以下 Cr：13重量％以上27重量％以下 Al：3.5重量％以上８重量％以下 La：0.05重量％を超え、0.20重量％未満 Nd：0.001重量％以上0.03重量％未満、かつ
LaとNdの合計が0.20重量％以下 を含み、残分がFeと不可避不純物よりなること
を特徴とする酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金。 ４ Ｃ：0.02重量％以下 Si：1.5重量％以下 Cr：13重量％以上27重量％以下 Al：3.5重量％以上８重量％以下 La：0.05重量％を超え、0.20重量％未満 Nd：0.001重量％以上0.03重量％未満、かつ
LaとNdの合計が0.20重量％以下 Ti：Ｃ重量％の５倍以上0.10重量％以下 を含み、残分がFeと不可避不純物よりなること
を特徴とする酸化スケールの耐剥離性に優れた
Fe−Cr−Al系合金。[Claims] 1 C: 0.02 wt% or less Si: 1.5 wt% or less Cr: 13 wt% or more and 27 wt% or less Al: 3.5 wt% or more and 8 wt% or less La: More than 0.05 wt% and 0.20 wt% Contains the following, with the remainder consisting of Fe and unavoidable impurities. Excellent peeling resistance of oxide scale.
Fe-Cr-Al alloy. 2 C: 0.02 wt% or less Si: 1.5 wt% or less Cr: 13 wt% or more and 27 wt% or less Al: 3.5 wt% or more and 8 wt% or less La: More than 0.05 wt% and 0.20 wt% or less Ti: C weight% It has excellent peeling resistance of oxide scale, characterized by containing 5 times or more and 0.10% by weight or less of
Fe-Cr-Al alloy. 3 C: 0.02 wt% or less Si: 1.5 wt% or less Cr: 13 wt% or more and 27 wt% or less Al: 3.5 wt% or more and 8 wt% or less La: More than 0.05 wt% and less than 0.20 wt% Nd: 0.001 wt% More than 0.03% by weight, and
Contains a total of 0.20% by weight or less of La and Nd, with the remainder consisting of Fe and unavoidable impurities. Excellent peeling resistance of oxide scale.
Fe-Cr-Al alloy. 4 C: 0.02 wt% or less Si: 1.5 wt% or less Cr: 13 wt% or more and 27 wt% or less Al: 3.5 wt% or more and 8 wt% or less La: More than 0.05 wt% and less than 0.20 wt% Nd: 0.001 wt% More than 0.03% by weight, and
Excellent peeling resistance of oxide scale characterized by a total content of La and Nd of 0.20% by weight or less, Ti: 5 times or more of C and 0.10% by weight or less, with the remainder consisting of Fe and unavoidable impurities.
Fe-Cr-Al alloy.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP87400917A EP0246939B1 (en) | 1986-04-21 | 1987-04-21 | Fe-cr-al stainless steel having high oxidation resistance and spalling resistance and fe-cr-al steel foil for catalyst substrate of catalytic converter |
| DE8787400917T DE3780082T2 (en) | 1986-04-21 | 1987-04-21 | STAINLESS CHROME-ALUMINUM STEEL WITH HIGH RESISTANCE TO OXYDATION AND PEELING AND CHROME-ALUMINUM STEEL FILMS FOR CATALYST CARRIERS IN CATALYTIC CONVERTERS. |
| US07/266,264 US4904540A (en) | 1986-04-21 | 1988-10-26 | Fe-Cr-Al stainless steel having high oxidation resistance and spalling resistance and Fe-Cr-Al steel for catalyst substrate of catalytic converter |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61-91815 | 1986-04-21 | ||
| JP9181586 | 1986-04-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6345351A JPS6345351A (en) | 1988-02-26 |
| JPH048502B2 true JPH048502B2 (en) | 1992-02-17 |
Family
ID=14037131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21877686A Granted JPS6345351A (en) | 1986-04-21 | 1986-09-17 | Fe-cr-al alloy having superior resistance to stripping of oxide scale |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6345351A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01255648A (en) * | 1988-04-05 | 1989-10-12 | Kawasaki Steel Corp | Fe-cr-al alloy excellent in oxidation resistance and resistance to high temperature embrittlement |
| JPH068486B2 (en) * | 1989-03-27 | 1994-02-02 | 新日本製鐵株式会社 | Heat- and oxidation-resistant Fe-Cr-A (1) type alloy with excellent manufacturability |
| JPH04354850A (en) * | 1991-05-29 | 1992-12-09 | Nisshin Steel Co Ltd | High al-containing ferritic stainless steel excellent in high temperature oxidation resistance |
| WO1994021836A1 (en) * | 1993-03-19 | 1994-09-29 | Nippon Yakin Kogyo Co., Ltd. | Ferritic stainless steel excellent in oxidation resistance |
| JP4684645B2 (en) * | 2004-12-22 | 2011-05-18 | 新日鉄マテリアルズ株式会社 | Metal carrier for catalyst support with excellent structural durability |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49115927A (en) * | 1973-03-10 | 1974-11-06 | ||
| JPS58177437A (en) * | 1982-04-12 | 1983-10-18 | アレゲニ−・ラドラム・スチ−ル・コ−ポレ−シヨン | Iron-chromium-aluminum alloy, product and manufacture |
| JPS6092071A (en) * | 1983-10-27 | 1985-05-23 | Toshiba Corp | Belt for brazing furnace |
-
1986
- 1986-09-17 JP JP21877686A patent/JPS6345351A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49115927A (en) * | 1973-03-10 | 1974-11-06 | ||
| JPS58177437A (en) * | 1982-04-12 | 1983-10-18 | アレゲニ−・ラドラム・スチ−ル・コ−ポレ−シヨン | Iron-chromium-aluminum alloy, product and manufacture |
| JPS6092071A (en) * | 1983-10-27 | 1985-05-23 | Toshiba Corp | Belt for brazing furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6345351A (en) | 1988-02-26 |
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