JPH10130813A - Heating furnace tube excellent in heat resistance, and its production - Google Patents
Heating furnace tube excellent in heat resistance, and its productionInfo
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- JPH10130813A JPH10130813A JP28214796A JP28214796A JPH10130813A JP H10130813 A JPH10130813 A JP H10130813A JP 28214796 A JP28214796 A JP 28214796A JP 28214796 A JP28214796 A JP 28214796A JP H10130813 A JPH10130813 A JP H10130813A
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- heating furnace
- furnace tube
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は1150℃以上16
00℃にも及ぶ超高温域において使用可能な耐熱性に優
れた加熱炉管およびその製造方法に関する。BACKGROUND OF THE INVENTION
The present invention relates to a heating furnace tube having excellent heat resistance and usable in an ultra-high temperature range of up to 00 ° C. and a method for manufacturing the same.
【0002】[0002]
【従来の技術】酸化スケ−ルを生成させずに鋼材を加熱
する炉として、光輝焼鈍炉が知られている。この炉は燃
焼ガスをラジアントチュ−ブとよばれる加熱炉管内部に
流し管内部で燃焼させつつ炉内を間接的に加熱する一
方、炉雰囲気は人工的に合成された還元性ガスとして鋼
材の酸化を防止するタイプの炉である。鋼材に酸化スケ
−ルが生成しないため、スケ−ルロス分の歩留まり向
上、酸洗もしくは脱スケ−ル工程省略、又は製品の表面
品質劣化防止などが可能となるため、炭素鋼、低合金鋼
等の熱処理に広く用いられている。以後の説明において
接頭語“光輝”がついた各種の炉は、“酸化スケールが
発生しない”各種の炉を意味する。2. Description of the Related Art A bright annealing furnace is known as a furnace for heating a steel material without generating an oxide scale. In this furnace, the combustion gas flows into a heating furnace tube called a radiant tube, which indirectly heats the inside of the furnace while burning the inside of the tube, while the furnace atmosphere is made of a steel material as an artificially synthesized reducing gas. This type of furnace prevents oxidation. Since no oxide scale is generated on the steel material, it is possible to improve the yield of the scale loss, omit the pickling or descaling process, or prevent the surface quality of the product from deteriorating. For example, carbon steel, low alloy steel, etc. Widely used for heat treatment. In the following description, various furnaces prefixed with “bright” mean various furnaces “without generation of oxide scale”.
【0003】このタイプの光輝熱処理炉は、用いられる
ラジアントチュ−ブ用材料の耐熱温度がせいぜい115
0℃程度までのため、鋼材の加熱温度は1000℃程度
が上限となる。このため光輝炉は炭素鋼や低合金鋼の製
品の熱処理には適用できても、下記の場合には適用が不
可能であった。In this type of bright heat treatment furnace, the heat resistant temperature of the radiant tube material used is at most 115.
Since the temperature is up to about 0 ° C., the upper limit of the heating temperature of the steel material is about 1000 ° C. For this reason, the bright furnace can be applied to heat treatment of carbon steel or low alloy steel products, but cannot be applied in the following cases.
【0004】(a)炭素鋼、低合金鋼、ステンレス鋼等
のスラブ、ビレット等を熱間圧延前に1200〜130
0℃にまで加熱する場合。(A) Slabs, billets, etc. of carbon steel, low alloy steel, stainless steel, etc., are subjected to hot rolling at a temperature of 1200 to 130 before hot rolling.
When heating to 0 ° C.
【0005】(b)ステンレス鋼、高Cr高Ni合金等
の溶体化熱処理のように加熱温度が1000℃を超える
場合。(B) When the heating temperature exceeds 1000 ° C. as in the solution heat treatment of stainless steel, high Cr high Ni alloy, etc.
【0006】1150℃以上の温度域(以後、超高温域
という)において使用可能な耐熱性にすぐれたラジアン
トチュ−ブ材が得られれば、上記(a)および(b)の
場合にも光輝炉が適用できる。その結果、上記のスケー
ルロスの減少等の諸効果が超高温加熱の場合にもそのま
ま得られるほかに、下記する品質向上に対する大きな効
果をあげることができる。If a radiant tube material excellent in heat resistance which can be used in a temperature range of 1150 ° C. or more (hereinafter referred to as an ultra-high temperature range) is obtained, a bright furnace can be obtained in the above cases (a) and (b). Can be applied. As a result, various effects such as the above-described reduction in scale loss can be obtained as they are even in the case of heating at an ultra-high temperature, and also a great effect on quality improvement described below can be obtained.
【0007】(イ)従来技術では不可能であったビレッ
ト又はスラブの脱炭を完全に防止できるため、最終製品
の表面品質を著しく向上できる。1300℃程度まで加
熱能力のある光輝炉は、ステンレス鋼のスラブ又はビレ
ット加熱にも適用でき、熱間圧延時の表面疵の主な原因
である鋼の異常酸化を抑制できるため、画期的な表面品
質の向上が計れる。(A) Since the decarburization of billets or slabs, which was impossible with the prior art, can be completely prevented, the surface quality of the final product can be significantly improved. A bright furnace capable of heating up to about 1300 ° C. can also be applied to stainless steel slab or billet heating, and can suppress abnormal oxidation of steel, which is a main cause of surface flaws during hot rolling, so it is revolutionary. Surface quality can be improved.
【0008】(ロ)ステンレス鋼又は高Cr高Ni合金
等の光輝熱処理炉に適用する場合には従来の酸洗や脱ス
ケ−ル工程を省略できるのみにとどまらず、とくにオ−
ステナイト系高Cr合金で従来技術では合金表面に不可
避的に生成する脱Cr層の形成を防止できるため、製品
の耐食性が従来法に比し飛躍的に向上する利点を有す
る。(B) When applied to a bright heat treatment furnace of stainless steel or high Cr high Ni alloy, etc., not only can the conventional pickling and descaling steps be omitted, but especially
In the prior art, since the formation of a Cr-free layer inevitably generated on the surface of the alloy can be prevented by the conventional technique using a high Cr austenitic alloy, there is an advantage that the corrosion resistance of the product is dramatically improved as compared with the conventional method.
【0009】このような大きな効果を得ることを目的に
従来より超高温域の使用に耐えるラジアントチューブ用
材料の提案がなされてきた。For the purpose of obtaining such a great effect, there has been conventionally proposed a material for a radiant tube which can withstand use in an ultra-high temperature range.
【0010】1150℃以上の超高温において耐熱性に
優れる材料として、従来からMo等の耐火金属(refrac
tory metal)の珪化物MoSi2 等が知られている。そ
の一例として、MoSi2 を構成するMoおよびSiか
らなる溶湯を特定の鋳型回転数で遠心鋳造することによ
り空孔比率を2体積%以下としたMoSi2 の加熱炉管
の提案がなされている(特開平07−331377号公
報)。As a material having excellent heat resistance at an extremely high temperature of 1150 ° C. or more, a refractory metal such as Mo (refrac.
For example, silicide MoSi 2 of tory metal) is known. As one example, there has been proposed a heating furnace tube of MoSi 2 in which a porosity is set to 2% by volume or less by centrifugally casting a molten metal including Mo and Si constituting MoSi 2 at a specific mold rotation speed ( JP-A-07-331377).
【0011】また、Si:35〜45%、Co:25%
以下、Ni:25%以下、Fe:10%以下を含む耐熱
性に優れたMo−Si系合金も開示されている(特願平
07−78747号公報)。Further, Si: 35-45%, Co: 25%
Hereinafter, a Mo-Si based alloy containing Ni: 25% or less and Fe: 10% or less and having excellent heat resistance is also disclosed (Japanese Patent Application No. 07-78747).
【0012】これら特開平07−331377号公報や
特願平07−78747号公報で示されている技術は、
Moの珪化物を主体とする一種のセラミックスを加熱炉
管として適用しようというものである。The techniques disclosed in Japanese Patent Application Laid-Open No. 07-331377 and Japanese Patent Application No. 07-78747 are disclosed in
It is intended to apply a kind of ceramic mainly composed of Mo silicide as a heating furnace tube.
【0013】しかしながら、これらの遠心鋳造管は熱間
又は冷間で曲げ加工を加えると破損してしまうため、パ
ネル等などに成形することは困難である。またセラミッ
クスであるが故に、溶接しようにもTIG溶接法など既
存の溶接法では溶接できない問題点も有している。However, these centrifugally cast tubes are damaged when subjected to bending in a hot or cold state, so that it is difficult to form them into panels or the like. In addition, since it is a ceramic, it has a problem that it cannot be welded by an existing welding method such as a TIG welding method.
【0014】また、Si:0.3%以上20%未満、残
部はMoからなる1300〜2000℃の温度域で大き
な耐クリ−プ性を示すモリブデン合金が開示されている
(国際公開番号:WO85/03953)。Further, there has been disclosed a molybdenum alloy comprising Si: 0.3% or more and less than 20%, with the balance being Mo and having a high creep resistance in a temperature range of 1300 to 2000 ° C. (International Publication No. WO85). / 03953).
【0015】しかし、この合金は、耐クリ−プ性は優れ
るものの、燃焼ガスのような酸化性の厳しい高温酸化環
境下では容易に焼損してしまい、本発明が目的とする環
境には適用できない問題点がある。[0015] However, although this alloy has excellent creep resistance, it is easily burned off in a high-temperature oxidizing environment such as combustion gas, which is severely oxidative, and cannot be applied to the environment aimed at by the present invention. There is a problem.
【0016】さらに、スラリ−を用いてNbにMoSi
2 をコ−ティングして耐熱性を高める技術が開示されて
いる(T.A.Kircher et.al:Materials Science and Engi
neering,A155(1992)p.67)。Further, MoSi is added to Nb using a slurry.
2 has been disclosed (TAKircher et. Al: Materials Science and Engi).
neering, A155 (1992) p.67).
【0017】しかし、スラリーを用いてMoSi2 をコ
ーティングしたNb管は、同文献にも示されるように処
理被膜が加熱冷却過程で容易に割れて剥離してしまい、
きわめて短時間に焼損してしまう欠点を有している。However, in the case of an Nb tube coated with MoSi 2 using a slurry, the treated coating is easily cracked and peeled off in the heating and cooling process, as shown in the document,
It has the disadvantage of burning out in a very short time.
【0018】[0018]
【発明が解決しようとする課題】本発明の目的は、熱間
又は冷間で曲げ加工でき、しかも従来の溶接法により溶
接可能な、1150℃以上の超高温域にて繰り返し使用
可能な耐熱性に優れた加熱炉管およびその製造方法を提
供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-resistant material which can be bent by hot or cold and which can be welded by a conventional welding method and which can be repeatedly used in an ultra-high temperature range of 1150 ° C. or more. It is an object of the present invention to provide a heating furnace tube having excellent heat resistance and a manufacturing method thereof.
【0019】[0019]
【課題を解決するための手段】本発明者らは、各種材料
について、超高温域での強度、常温又は熱間での曲げ加
工、および溶接性を検討した結果、つぎの事項を確認す
ることができた。Means for Solving the Problems The present inventors have studied the strength in ultra-high temperature range, bending at room temperature or hot, and weldability of various materials, and confirmed the following items. Was completed.
【0020】(a)耐熱金属のうち、Mo基合金は加工
ができ、かつ溶接も通常のTIG溶接が可能なので、加
熱炉管のベースとなる合金はMoを主成分とする合金、
すなわちMo基合金が最有力である。(A) Among heat-resistant metals, Mo-based alloys can be processed and welding can be performed by ordinary TIG welding. Therefore, the base alloy of the heating furnace tube is an alloy containing Mo as a main component.
That is, the Mo-based alloy is the most promising.
【0021】(b)しかしながらMo基合金は燃焼ガス
環境下では容易に酸化焼損してしまうため、加熱炉管表
面に耐酸化性の被膜を施す必要がある。(B) However, since the Mo-based alloy is easily oxidized and burned out in a combustion gas environment, it is necessary to apply an oxidation-resistant coating on the surface of the heating furnace tube.
【0022】(c)本発明が目的とする加熱炉又は熱処
理炉では、1月〜3月おきに定期点検がなされるため、
加熱炉管には加熱と冷却が繰り返される。したがってM
o基合金に施す被膜は、耐高温酸化性のみならず、加熱
と冷却の繰り返しで剥離や割れが生じない強固な性質を
有する必要がある。このような目的を達成する方法とし
て、拡散浸透処理によって表層部の一定範囲にSi又は
Alの含有率を高めた被膜を形成することが有効であ
る。(C) In the heating furnace or the heat treatment furnace which is the object of the present invention, periodic inspection is performed every January to three months.
Heating and cooling are repeated in the heating furnace tube. Therefore M
The coating applied to the o-based alloy needs to have not only high-temperature oxidation resistance but also strong properties such that peeling and cracking do not occur due to repeated heating and cooling. As a method for achieving such an object, it is effective to form a coating film in which a content of Si or Al is increased in a certain range of a surface layer portion by diffusion infiltration treatment.
【0023】本発明は上記の事項を組み合わせ、実際に
超高温への加熱と冷却を繰り返しその効果を確認し改良
を重ねて完成されたものである。The present invention has been completed by combining the above items, actually repeating the heating and cooling to an extremely high temperature, confirming the effects thereof, and repeatedly improving.
【0024】本発明は、下記の加熱炉管およびその製造
方法を要旨とする。The gist of the present invention is the following heating furnace tube and a method of manufacturing the same.
【0025】(1)重量%で、Fe:15%以下および
下記の合金元素A群、B群、C群を含むMoを主成分
とする合金管であって、SiおよびAlの含有率がとも
に表層部において内部より高い耐熱性に優れた加熱炉管
(〔発明1〕とする)。(1) An alloy tube containing Mo as a main component and containing Fe: 15% or less and the following alloy elements A, B, and C in terms of% by weight. A heating furnace tube having a higher heat resistance than the inside in the surface layer portion (referred to as [Invention 1]).
【0026】合金元素 A群:(Cr,W,Ti,Nb,Ta,Co,Ni,Mn,Cu)の1種以上の合計が
0〜5% B群:(C,N)の1種以上の合計が0〜0.5% C群:(Ca,Mg,B,REM)の1種以上の合計が0〜0.1% (2)重量%で、Fe:15%以下および下記の合金
元素A群、B群、C群を含むMoを主成分とする合金管
に対して、下記の成分組成の拡散浸透処理剤中で、1
000℃以上の温度域で拡散浸透処理する耐熱性に優れ
た加熱炉管の製造方法(〔発明2〕とする)。Alloying elements Group A: 0 to 5% in total of one or more of (Cr, W, Ti, Nb, Ta, Co, Ni, Mn, Cu) Group B: One or more of (C, N) Group C: 0% to 0.1% of the total of one or more of (Ca, Mg, B, REM) (2)% by weight, Fe: 15% or less and the following alloys An alloy tube containing Mo as a main component, which includes the elements A, B, and C, is mixed with a diffusion / penetration treatment agent having the following component composition.
A method for manufacturing a heating furnace tube having excellent heat resistance for performing diffusion and infiltration treatment in a temperature range of 000 ° C. or higher (referred to as [Invention 2]).
【0027】合金元素 A群:(Cr,W,Ti,Nb,Ta,Co,Ni,Mn,Cu)の1種以上の合計で
0〜5% B群:(C,N)の1種以上の合計で0〜0.5% C群:(Ca,Mg,B,REM)の1種以上の合計で0〜0.1% 拡散浸透処理剤 10%以下のAlを含む塊状Si基合金である浸透剤:
50〜90%、反応促進剤:0.5〜5%、および焼結
防止剤を含む拡散浸透処理剤。Alloying elements Group A: 0 to 5% in total of one or more of (Cr, W, Ti, Nb, Ta, Co, Ni, Mn, Cu) Group B: One or more of (C, N) 0 to 0.5% in total of group C: 0 to 0.1% in total of one or more of (Ca, Mg, B, REM) Diffusion infiltration treatment agent A massive Si-based alloy containing 10% or less of Al Some penetrants:
A diffusion infiltration treatment agent containing 50 to 90%, a reaction accelerator: 0.5 to 5%, and a sintering inhibitor.
【0028】上記においてFeを15%以下含むMoを
主成分とする合金は、A群、B群、C群のうちの1種以
上を含むMo基合金であるが、各群はいずれも0%の場
合も含むので、A群、B群、C群のいずれの合金元素も
含まない場合、すなわち実質Mo−Fe合金および実質
Moも該当する。In the above, the alloy mainly containing Mo containing 15% or less of Fe is a Mo-based alloy containing at least one of Group A, Group B, and Group C. Therefore, the case where none of the alloy elements of the group A, the group B, and the group C is included, that is, the substantial Mo—Fe alloy and the substantial Mo is also applicable.
【0029】〔発明1〕において、「表層部」とは、S
iおよびAlの含有率が表面から内部にかけて減少する
分布になっていることを前提として、“表面から少なく
とも表層部の深さ0.1mmの位置まで”をさし、通常
は0.1mm以上内部に入った位置までをさす。In [Invention 1], the “surface layer” means S
Assuming that the contents of i and Al are distributed from the surface to the inside, the term "from the surface to at least the position of the surface layer at a depth of 0.1 mm" is usually used. To the position where it entered.
【0030】「SiおよびAlの含有率がともに表層部
において内部より高い」とは、表面から深さ0.1mm
の位置でのSiおよびAlの含有率がそれぞれ内部より
0.1%以上高いことをさす。表層部の各位置における
Si又はAlの含有率の測定は、EPMA(Electron P
robe Micro-Analyser)等により行うことができる。"The content of both Si and Al is higher in the surface layer than in the interior" means that the depth from the surface is 0.1 mm.
Means that the content of Si and Al at the position is higher than the inside by 0.1% or more, respectively. The measurement of the content of Si or Al at each position of the surface layer is performed by EPMA (Electron P).
robe Micro-Analyser) or the like.
【0031】以後の説明において、拡散浸透処理により
加熱炉管の表層部に形成されるSi又はAlの含有率の
高い部分を単に“被膜”という場合がある。したがっ
て、“拡散浸透処理を施された表層部の深さ”と“被膜
厚さ”とは同じものを指している。In the following description, a portion having a high Si or Al content formed on the surface layer of the heating furnace tube by the diffusion and infiltration treatment may be simply referred to as a “coating”. Therefore, the "depth of the surface portion subjected to the diffusion and infiltration treatment" and the "film thickness" indicate the same.
【0032】上記〔発明2〕において「塊状Si基合
金」とは比較的小サイズの“塊状”のものを指し、“粉
状”の範疇に入るものも一部に含む。「塊」とは、針
状、平面的な形状、偏平体等でないことをさし、たとえ
ば、立方体、長辺と短辺の長さの比が2以内程度の直方
体、長径と短径の比が2以内程度の回転楕円体等が該当
する。「塊の粒径」は塊の長径をさす。In the above [Invention 2], the term "bulk Si-based alloy" refers to a relatively small-sized "lumpy" alloy, and includes a part in the category of "powder". "Lump" means not a needle, a planar shape, a flat body, etc., and is, for example, a cube, a rectangular parallelepiped having a length ratio of a long side to a short side of about 2 or less, or a ratio of a long diameter to a short diameter. Corresponds to a spheroid of about 2 or less. "Lump particle size" refers to the major diameter of the lump.
【0033】本明細書において「耐熱性」とは、“高温
強度およびクリープ性能”、“耐高温酸化性”および
“耐剥離性”のいずれをも備えた性質を意味する。As used herein, the term "heat resistance" means a property having all of "high temperature strength and creep performance", "high temperature oxidation resistance" and "peeling resistance".
【0034】[0034]
【発明の実施の形態】つぎに本発明を上記のように限定
した理由について説明する。下記の説明において、とく
にことわらないかぎり、「%」は「重量%」を表示する
ものとする。Next, the reason why the present invention is limited as described above will be described. In the following description, “%” indicates “% by weight” unless otherwise specified.
【0035】1.加熱炉管の材質 加熱炉管の材質は、下記の合金を含むMoを主成分とす
る合金とする。1. Material of Heating Furnace Tube The material of the heating furnace tube is an alloy containing Mo as a main component and containing the following alloys.
【0036】Fe:15%以下 本発明の加熱炉管は、Feを15%以下含むものとす
る。Feは合金管のコストを下げるために、10%以上
とすることが望ましい。しかし、15%を超えると合金
の融点が低下し、使用温度域である超高温で溶融してし
まうので、15%以下とする。Fe: 15% or less The heating furnace tube of the present invention contains 15% or less of Fe. Fe is desirably 10% or more to reduce the cost of the alloy tube. However, if it exceeds 15%, the melting point of the alloy decreases, and the alloy melts at an extremely high temperature, which is the operating temperature range.
【0037】上記のFeに加えて、本発明に係る被処理
管の合金成分として、前記の合金元素のA群、B群、
C群を含むものとする。In addition to the above-mentioned Fe, alloy components of the above-mentioned alloying elements A group, B group,
Group C is included.
【0038】つぎに各群の範囲を限定した理由について
説明する。Next, the reason why the range of each group is limited will be described.
【0039】A群:A群の元素は含まれていなくてもよ
い。A群の元素はいずれも超高温域での高温強度を改善
する作用を有する。すなわち、これらの合金元素はマト
リックス中に固溶し、加熱炉管の高温強度の向上に寄与
する。使用温度が高く、その効果を積極的に得たい場合
には含ませるが、0.1%未満では効果が明確に現れな
いので、含ませる場合には0.1%以上とするのが望ま
しい。一方、それらの合計が5%を超えると、金属組織
中に脆い第二相( たとえば、Cr2Moなど)が析出
し、加熱炉管の靱性の低下を招くため、その上限を5%
とする。Group A: The elements of Group A may not be contained. All of the elements in Group A have an effect of improving high-temperature strength in an ultra-high temperature range. That is, these alloy elements form a solid solution in the matrix and contribute to improvement of the high-temperature strength of the heating furnace tube. If the use temperature is high and the effect is desired to be obtained positively, the effect is included. However, if the effect is less than 0.1%, the effect is not clearly exhibited. On the other hand, if the total of them exceeds 5%, a brittle second phase (for example, Cr 2 Mo) precipitates in the metal structure and causes a decrease in the toughness of the heating furnace tube.
And
【0040】B群:B群の元素は含まれていなくてもよ
い。B群の元素もA群の元素と同様いずれも超高温域で
の高温強度を改善する作用を有する。すなわち、これら
の合金元素はマトリックス中に固溶し、加熱炉管の高温
強度の向上に寄与する。低合金鋼スラブの圧延前の加熱
等に使用される場合で、高温強度を一層高めたい場合に
は、必要に応じて含ませる。しかし、0.01%未満で
は高温強度の向上が不十分なので含ませる場合には0.
01%以上とするのが望ましい。一方、それらの合計が
0.5%を超えると、金属組織中にMoの炭化物や窒化
物が過剰に析出し靱性の低下を招くため、その上限を
0.5%とする。Group B: The elements of Group B may not be contained. Each of the elements in group B, like the elements in group A, has an effect of improving high-temperature strength in an ultra-high temperature range. That is, these alloy elements form a solid solution in the matrix and contribute to improvement of the high-temperature strength of the heating furnace tube. When used for heating of a low-alloy steel slab before rolling or the like, and when it is desired to further increase the high-temperature strength, it is included as necessary. However, if the content is less than 0.01%, the improvement in high-temperature strength is insufficient, so that if the content is to be included, the content of 0.1% is not preferable.
Desirably, it is not less than 01%. On the other hand, if the sum of them exceeds 0.5%, Mo carbides and nitrides are excessively precipitated in the metal structure to cause a decrease in toughness, so the upper limit is made 0.5%.
【0041】C群:C群の元素は含まれていなくてもよ
い。C群の元素はいずれも合金の加工性を改善する。す
なわちこれらの元素は合金中のO(酸素)と反応し、合
金の加工性を損ねる作用を有する固溶酸素量を低減さ
せ、加熱炉管の加工性改善に寄与する。このため、大き
な加工を必要とする部材に使用される場合には含ませ
る。しかし、0.001%未満では加工性の向上は不十
分なので含ませる場合には0.001%以上とすること
が望ましい。一方、それらの合計含有率が0.1%を超
えるとかえって加工性が低下するので、その上限を0.
1%とする。Group C: The elements of Group C need not be contained. All elements of group C improve the workability of the alloy. That is, these elements react with O (oxygen) in the alloy, reduce the amount of dissolved oxygen having an effect of impairing the workability of the alloy, and contribute to improving the workability of the heating furnace tube. For this reason, it is included when it is used for a member requiring a large processing. However, if the content is less than 0.001%, the workability is not sufficiently improved. On the other hand, if their total content exceeds 0.1%, the workability is rather reduced.
1%.
【0042】上記のMo基合金は、通常の製造方法によ
って除けないP、S、O等の不可避的不純物を含む。The above Mo-based alloy contains unavoidable impurities such as P, S and O which cannot be removed by a normal manufacturing method.
【0043】2.表層部 表面から内部にかけてSiおよびAlの含有率が減少す
る分布になっていることを前提として、少なくとも表面
から0.1mmの位置では、SiおよびAlの含有率は
ともに内部のそれより高くなければならない。少なくと
も深さ0.1mmの位置でSiおよびAlの含有率がそ
れぞれ内部より高くないと耐熱性を確保できない。上記
したように深さ0.1mmで内部より高いとは、0.1
%以上高いことを意味する。2. Assuming that the distribution of the content of Si and Al decreases from the surface to the interior, the content of Si and Al must be higher than that of the interior at least at a position of 0.1 mm from the surface. No. Heat resistance cannot be ensured unless the contents of Si and Al are higher than the inside at least at a depth of 0.1 mm. As described above, a depth of 0.1 mm and a height higher than the inside means 0.1 mm.
% Or higher.
【0044】さらに、超高温域での耐酸化性を確保する
ためには、表層部の深さ0.1mmの位置にてSiおよ
びAlの合計で35%以上含んでいることが望ましい。
この位置にてSiおよびAlの合計が35%未満である
と、つぎの問題を生じ、本発明の目的を達成することが
できない場合がある。Further, in order to ensure oxidation resistance in an ultra-high temperature range, it is desirable that the total content of Si and Al is 35% or more at a position of a surface layer portion having a depth of 0.1 mm.
If the sum of Si and Al at this position is less than 35%, the following problem occurs, and the object of the present invention may not be achieved.
【0045】(a)超高温域での耐酸化性に優れるAl
2O3、SiO2 等の被膜が合金表面に均一に生成しな
い。(A) Al having excellent oxidation resistance in an ultra-high temperature range
Films such as 2 O 3 and SiO 2 are not uniformly formed on the alloy surface.
【0046】(b)SiおよびAlの合計で35%以上
となる被膜厚さが0.1mm未満の場合、超高温域で長
時間(たとえば1万時間程度)使用中に、表層部中のS
iおよびAlが基質であるMo基合金中に拡散し、被膜
中のSiおよびAlの含有率が低下してしまい、被膜の
耐酸化性が劣化してしまう。(B) If the total thickness of Si and Al is 35% or more and the coating thickness is less than 0.1 mm, the S in the surface layer portion may be used for a long time (for example, about 10,000 hours) in an ultra-high temperature range.
i and Al diffuse into the Mo-based alloy as a substrate, and the content of Si and Al in the coating decreases, and the oxidation resistance of the coating deteriorates.
【0047】したがって、表層部の深さ0.1mmの位
置において、SiおよびAlの合計を35%以上含有さ
せることが望ましい。このとき、前記したようにSiお
よびAlの濃度分布は表面から内部にかけて減少する分
布になっていることを前提としており、この前提は常に
満たされている。Therefore, it is desirable that the total content of Si and Al should be 35% or more at the position of the surface layer portion having a depth of 0.1 mm. At this time, as described above, it is assumed that the concentration distribution of Si and Al is a distribution that decreases from the surface to the inside, and this assumption is always satisfied.
【0048】一方、表層部の深さ0.1mmの地点でS
iおよびAlの合計が45%を超えると、耐剥離性が劣
化する場合があるので45%以下とすることが望まし
い。また、この被膜厚さは耐酸化性の点から厚いほど良
好だが、SiおよびAlの合計が35%となる被膜厚さ
が0.3mmを超えると耐熱衝撃性が劣化する場合があ
り、また、コストがかさむことからも、被膜厚さは0.
3mm程度以下が好ましい。On the other hand, at the point of the surface layer portion having a depth of 0.1 mm, S
If the sum of i and Al exceeds 45%, the peeling resistance may deteriorate. The thickness of the coating is preferably as thick as possible from the viewpoint of oxidation resistance. However, if the coating having a total of 35% of Si and Al exceeds 0.3 mm, the thermal shock resistance may be deteriorated. Because of the increased cost, the thickness of the coating film should be less than 0.1.
It is preferably about 3 mm or less.
【0049】3.拡散浸透処理 次いで拡散浸透処理条件の限定理由について述べる。3. Diffusion and infiltration treatment Next, the reasons for limiting the diffusion and infiltration treatment conditions will be described.
【0050】3−1.拡散浸透処理剤 拡散浸透処理は前記の拡散浸透処理剤の中で行われ
る。なお、「拡散浸透処理剤」のことを、単に“処理
剤”という場合がある。3-1. Diffusion-penetration treatment agent The diffusion-penetration treatment is performed in the above-mentioned diffusion-penetration treatment agent. Note that the “diffusion infiltration agent” may be simply referred to as “treatment agent”.
【0051】処理材を上記の成分組成に限定した理由は
下記のとおりである。The reason why the treatment material is limited to the above-mentioned component composition is as follows.
【0052】浸透剤:Alを10%以下含むSi基合金
を浸透剤として用いる理由は、拡散浸透処理によって生
じる被膜の密着性、すなわち耐剥離性を向上させるため
である。Alが10%を超えると材料表面にSiO2 の
被膜が生成しなくなり耐酸化性が劣化するため10%以
下とする。一方、Alの含有率が0.1%未満のときに
は、耐剥離性に優れた被膜が得られない場合があるの
で、0.1%以上とすることが望ましい。Penetrant: The reason why a Si-based alloy containing 10% or less of Al is used as the penetrant is to improve the adhesion of the film produced by the diffusion-penetration treatment, that is, the peeling resistance. If Al exceeds 10%, no SiO 2 film is formed on the surface of the material, and the oxidation resistance is deteriorated. On the other hand, when the Al content is less than 0.1%, a film having excellent peeling resistance may not be obtained, so that the content is preferably 0.1% or more.
【0053】Alを含むSi基合金の塊はそれぞれ粒径
が0.1〜3mm程度であることが望ましい。0.1〜
3mmの粒径のSi基合金の塊を浸透剤に用いるとS
i、AlのキャリアーガスであるSiCl4、AlCl4
が被処理材表面の一部に偏らずに全体に接触し表面全体
から均一にAl、Siが拡散できる。この結果、被処理
材には均一な被膜が得られる。It is desirable that the bulk of the Si-based alloy containing Al has a particle size of about 0.1 to 3 mm. 0.1 ~
When a lump of Si-based alloy having a particle size of 3 mm is used as a penetrant,
i, SiCl 4 , AlCl 4 as carrier gas of Al
Contact the entire surface of the material to be treated without bias, and Al and Si can be uniformly diffused from the entire surface. As a result, a uniform coating is obtained on the material to be processed.
【0054】Si基合金は浸透剤中で90%を超えて含
有されると拡散浸透処理後に浸透剤が加熱炉管に焼結し
てしまい、加熱炉管と浸透剤とを分離できなくなるの
で、90%以下とする。一方、Si基合金の含有率が5
0%未満のとき、加熱炉管の表層部に耐酸化性と耐剥離
性に優れた被膜が生成しないため50%以上とする。If the Si-based alloy exceeds 90% in the penetrant, the penetrant sinters into the heating furnace tube after the diffusion and infiltration treatment, and the heating furnace tube and the penetrant cannot be separated. 90% or less. On the other hand, when the content of the Si-based alloy is 5
When the content is less than 0%, a coating excellent in oxidation resistance and peeling resistance is not formed on the surface layer of the heating furnace tube, so that the content is set to 50% or more.
【0055】反応促進剤:反応促進剤としてはNH4C
lやNaCl、NH4Brなどの塩化物、臭化物を用い
ることができる。これら反応促進剤の合計が0.5%未
満では耐酸化性と耐剥離性に富んだ被膜が均一に加熱炉
管の表層部に生成されないので、浸透剤の含有率は0.
5%以上が必要である。しかし、5%を超えて含有させ
ると拡散浸透処理時に塩酸や臭酸ガスが発生し、作業上
好ましくないことから、上限を5%とする。Reaction accelerator: NH 4 C is used as the reaction accelerator.
1 and chlorides and bromides such as NaCl and NH 4 Br can be used. If the total of these reaction accelerators is less than 0.5%, a coating rich in oxidation resistance and peeling resistance is not uniformly formed on the surface layer of the heating furnace tube.
5% or more is required. However, if the content exceeds 5%, hydrochloric acid or bromic acid gas is generated during the diffusion and infiltration treatment, which is not preferable in terms of work, so the upper limit is set to 5%.
【0056】焼結防止剤:焼結防止剤としてはAl2O3
やムライトなど化学的に安定で安価な化合物を用いるこ
とができる。焼結防止剤は、拡散浸透処理剤中で5〜5
0%の範囲にあることが望ましい。拡散浸透処理剤中で
5%未満では焼結防止が十分ではなく、一方、50%を
超えると、被膜が生成しない。Sintering inhibitor: Al 2 O 3 is used as a sintering inhibitor.
Chemically stable and inexpensive compounds such as mullite and mullite can be used. The sintering inhibitor is 5 to 5 in the diffusion infiltration agent.
It is desirable to be in the range of 0%. If it is less than 5% in the diffusion infiltration treatment agent, sintering prevention is not sufficient, while if it exceeds 50%, no film is formed.
【0057】3−2.拡散浸透処理 拡散浸透処理温度:拡散浸透処理温度が1000℃未満
のとき、拡散反応が遅くなり処理時間が長時間必要とな
り処理コストが上昇することから、1000℃以上とす
る。一方、実用上は拡散浸透処理炉の寿命を考慮して1
200℃程度以下とすることが望ましい。3-2. Diffusion-penetration treatment Diffusion-penetration treatment temperature: When the temperature of the diffusion-penetration treatment is less than 1000 ° C., the diffusion reaction is slowed, the treatment time is required for a long time, and the treatment cost is increased. On the other hand, in practical use, 1
It is desirable that the temperature be about 200 ° C. or less.
【0058】拡散浸透処理時間:拡散浸透処理時間は1
時間以上とすることが望ましい。拡散浸透処理時間が1
時間未満のとき、十分な耐酸化性と耐剥離性を備えた被
膜が得られない場合がある。一方、あまり長時間になる
と、不必要に厚くかつAlおよびSiの含有率の高い被
膜が生成し耐剥離性が劣化する場合があり、また拡散浸
透処理に要する費用もかさむので50時間程度未満が望
ましい。Diffusion infiltration time: Diffusion infiltration time is 1
It is desirable that the time be longer than the time. Diffusion infiltration time 1
When the time is less than the time, a film having sufficient oxidation resistance and peel resistance may not be obtained. On the other hand, if the time is too long, an unnecessarily thick film having a high content of Al and Si may be formed and the peeling resistance may be degraded. In addition, the cost required for the diffusion and infiltration treatment is increased, so that it is less than about 50 hours. desirable.
【0059】雰囲気:拡散浸透処理は非酸化性の雰囲気
でおこなうことが望ましい。通常は、水素雰囲気中で行
うが、酸化が防止できれば必ずしも水素を用いなくても
よい。Atmosphere: It is desirable to perform the diffusion and infiltration treatment in a non-oxidizing atmosphere. Usually, the reaction is performed in a hydrogen atmosphere, but it is not always necessary to use hydrogen as long as oxidation can be prevented.
【0060】[0060]
【実施例】つぎに実施例により本発明の効果を説明す
る。EXAMPLES Next, the effects of the present invention will be described with reference to examples.
【0061】表1は加熱炉管を製作するために電気アー
ク炉で溶製したMo基合金の化学組成を示す。Table 1 shows the chemical composition of a Mo-based alloy melted in an electric arc furnace to produce a heating furnace tube.
【0062】[0062]
【表1】 [Table 1]
【0063】表1に示すMo基合金のインゴットから外
径50mm、肉厚5mm、長さ100mmのリングをく
り抜いて加熱炉管の模型とした。表1に示す合金は合金
の曲げ加工やTIG法による溶接が可能なことをあらか
じめ確認済みのものである。From the Mo-based alloy ingot shown in Table 1, a ring having an outer diameter of 50 mm, a thickness of 5 mm, and a length of 100 mm was hollowed out to obtain a model of a heating furnace tube. The alloys shown in Table 1 have been confirmed in advance that the alloy can be bent or welded by the TIG method.
【0064】表2は実験に用いた拡散浸透処理剤の組成
を示す。Si基合金は粒径0.3mmの塊(粉)状のも
のを用いた。また、表3は拡散浸透処理の条件を示す。Table 2 shows the composition of the diffusion / penetration treatment agent used in the experiment. The Si-based alloy used was a lump (powder) having a particle diameter of 0.3 mm. Table 3 shows the conditions of the diffusion and infiltration treatment.
【0065】[0065]
【表2】 [Table 2]
【0066】[0066]
【表3】 [Table 3]
【0067】上記のリングを表2に示す処理剤を用いて
表3に示す条件で粉末パック法により H2ガス通気中で
拡散浸透処理したのち、得られた表層部の被膜の厚さお
よび被膜中のSiとAlの含有率を分析した。表3中で
被膜厚さは、表面からAlとSiの和が内部より高い位
置までの距離をあらわす。また、被膜のSiまたはAl
の含有率は最表面から0.1mmの位置でのSiまたは
Alの含有率をあらわす。The above ring was subjected to a diffusion permeation treatment using a treating agent shown in Table 2 under the conditions shown in Table 3 in a H 2 gas flow by a powder packing method, and then the thickness and film thickness of the obtained surface layer portion were obtained. The contents of Si and Al therein were analyzed. In Table 3, the coating thickness represents the distance from the surface to a position where the sum of Al and Si is higher than the inside. In addition, Si or Al
Indicates the content of Si or Al at a position of 0.1 mm from the outermost surface.
【0068】被膜の厚さおよび被膜中のSiとAlの含
有率をあわせて表3に示す。Table 3 shows the thickness of the coating and the contents of Si and Al in the coating.
【0069】上記拡散浸透処理を施されたリングを、空
気中1450℃で100h加熱後室温まで冷却する加熱
と冷却の熱サイクルを10回施す熱サイクル試験を行
い、被膜の耐酸化性と耐剥離性を評価した。耐酸化性は
酸化増量により、また、耐剥離性は被膜の剥離の有無に
より評価した。The ring subjected to the diffusion and infiltration treatment was subjected to a heat cycle test of heating and cooling to room temperature after heating at 1450 ° C. for 100 hours in air, and 10 heat cycles of heating and cooling. The sex was evaluated. The oxidation resistance was evaluated by increasing the oxidation, and the peel resistance was evaluated by the presence or absence of peeling of the coating.
【0070】表4はこれらの試験結果を示す。Table 4 shows the results of these tests.
【0071】[0071]
【表4】 [Table 4]
【0072】比較例である試験番号33は表層部のAl
が内部よりも0.1%以上高くないために被膜が剥離し
てしまい、耐高温酸化性がいちじるしく低くなった。同
じく比較例である試験番号34は、拡散浸透処理剤に本
発明の範囲外の処理剤Hを用いたために表層部にAlと
Si含有率の高い被膜が形成されず熱サイクル試験後に
焼損を生じた。また、比較例の試験番号36は母合金が
Feを20.6%含有しているため、合金の融点が下が
り、耐酸化性の試験温度1450℃で一部溶融してしま
い耐酸化性の評価を行うことができなかった。Test No. 33, which is a comparative example, shows that Al
Was not higher than the inside by 0.1% or more, and the coating was peeled off, and the high-temperature oxidation resistance was extremely low. Test No. 34, which is also a comparative example, shows that a coating having a high content of Al and Si was not formed on the surface layer portion due to the use of the treatment agent H outside the range of the present invention as the diffusion and infiltration treatment agent, resulting in burnout after the heat cycle test. Was. In the test No. 36 of the comparative example, since the mother alloy contained 20.6% of Fe, the melting point of the alloy was lowered, and the alloy was partially melted at the oxidation resistance test temperature of 1450 ° C. to evaluate the oxidation resistance. Could not do.
【0073】これに対して、本発明に係るリングは、過
酷な加熱と冷却の熱サイクルにも耐え、1450℃とい
う超高温度においても良好な耐酸化性をしめすことが確
認できた。On the other hand, it was confirmed that the ring according to the present invention withstands severe heat cycles of heating and cooling, and shows good oxidation resistance even at an extremely high temperature of 1450 ° C.
【0074】[0074]
【発明の効果】本発明は1150℃を超える超高温酸化
性ガス雰囲気においてきわめて優れた耐高温酸化性を有
する加熱炉管およびその製造方法を提供する。本発明に
係るMo基合金は加熱炉管として必要な曲げ加工や溶接
が従来設備で容易に可能なだけでなく、拡散浸透処理に
よる被膜を有するため超高温域での高温強度や熱衝撃に
対しても十分な耐剥離性を備えている。According to the present invention, there is provided a heating furnace tube having extremely excellent high-temperature oxidation resistance in an ultra-high temperature oxidizing gas atmosphere exceeding 1150 ° C. and a method for producing the same. The Mo-based alloy according to the present invention is not only easily bent and welded as a heating furnace tube with conventional equipment, but also has a coating by diffusion infiltration processing, so that it can withstand high temperature strength and thermal shock in an ultra-high temperature range. It has sufficient peeling resistance.
【0075】本発明をラジアントチュ−ブに用いること
により、被加熱材の加熱温度が1300℃程度の光輝炉
の製造が可能となり、鉄鋼製造過程で生じるスケ−ルロ
スをはじめとする種々のスケ−ル問題を一挙に解決で
き、画期的な表面品質向上等を得ることができる。By using the present invention for a radiant tube, it is possible to manufacture a bright furnace in which the material to be heated has a heating temperature of about 1300 ° C., and various scales including scale loss generated in the steel manufacturing process. Problems can be solved at once, and epoch-making surface quality improvement can be obtained.
Claims (2)
の合金元素A群、B群、C群を含むMoを主成分とする
合金管であって、SiおよびAlの含有率がともに表層
部において内部より高いことを特徴とする耐熱性に優れ
た加熱炉管。 合金元素 A群:(Cr,W,Ti,Nb,Ta,Co,Ni,Mn,Cu)の1種以上の合計が
0〜5% B群:(C,N)の1種以上の合計が0〜0.5% C群:(Ca,Mg,B,REM)の1種以上の合計が0〜0.1%1. An alloy tube containing Mo as a main component and containing at least 15% by weight of Fe and the following alloy elements A, B and C, wherein the content of both Si and Al is in the surface layer. Heating furnace tube excellent in heat resistance characterized in that it is higher than the inside in the part. Alloying element Group A: Total of one or more of (Cr, W, Ti, Nb, Ta, Co, Ni, Mn, Cu) is 0 to 5% Group B: Total of one or more of (C, N) 0-0.5% Group C: Total of one or more of (Ca, Mg, B, REM) is 0-0.1%
の合金元素A群、B群、C群を含むMoを主成分とする
合金管に対して、下記の成分組成の拡散浸透処理剤中
で、1000℃以上の温度域で拡散浸透処理することを
特徴とする耐熱性に優れた加熱炉管の製造方法。 合金元素 A群:(Cr,W,Ti,Nb,Ta,Co,Ni,Mn,Cu)の1種以上の合計で
0〜5% B群:(C,N)の1種以上の合計で0〜0.5% C群:(Ca,Mg,B,REM)の1種以上の合計で0〜0.1% 拡散浸透処理剤 10%以下のAlを含む塊状Si基合金である浸透剤:
50〜90%、反応促進剤:0.5〜5%、および焼結
防止剤を含む拡散浸透処理剤。2. A diffusion / penetration treatment agent having the following composition with respect to an alloy pipe containing 15% or less of Fe by weight and containing Mo as a main component and containing the following alloy elements A, B and C: A method of manufacturing a heating furnace tube having excellent heat resistance, wherein diffusion heat treatment is performed in a temperature range of 1000 ° C. or more. Alloying elements Group A: 0 to 5% in total of one or more of (Cr, W, Ti, Nb, Ta, Co, Ni, Mn, Cu) Group B: Total of one or more of (C, N) 0 to 0.5% Group C: 0 to 0.1% in total of one or more of (Ca, Mg, B, REM) Diffusion infiltration agent Penetrant which is a massive Si-based alloy containing 10% or less of Al :
A diffusion infiltration treatment agent containing 50 to 90%, a reaction accelerator: 0.5 to 5%, and a sintering inhibitor.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28214796A JPH10130813A (en) | 1996-10-24 | 1996-10-24 | Heating furnace tube excellent in heat resistance, and its production |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28214796A JPH10130813A (en) | 1996-10-24 | 1996-10-24 | Heating furnace tube excellent in heat resistance, and its production |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH10130813A true JPH10130813A (en) | 1998-05-19 |
Family
ID=17648722
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP28214796A Pending JPH10130813A (en) | 1996-10-24 | 1996-10-24 | Heating furnace tube excellent in heat resistance, and its production |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH10130813A (en) |
-
1996
- 1996-10-24 JP JP28214796A patent/JPH10130813A/en active Pending
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