JPH07166290A - Heat resistant alloy excellent in carburization resistance and oxidation resistance - Google Patents
Heat resistant alloy excellent in carburization resistance and oxidation resistanceInfo
- Publication number
- JPH07166290A JPH07166290A JP31648893A JP31648893A JPH07166290A JP H07166290 A JPH07166290 A JP H07166290A JP 31648893 A JP31648893 A JP 31648893A JP 31648893 A JP31648893 A JP 31648893A JP H07166290 A JPH07166290 A JP H07166290A
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- carburization
- oxidation resistance
- tube
- oxide film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、石油化学工業における
エチレン製造用クラッキングチューブ、リフォーミング
チューブ等の材料として好適な耐熱合金に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant alloy suitable as a material for a cracking tube for ethylene production, a reforming tube and the like in the petrochemical industry.
【０００２】[0002]
【従来技術】出願人は、以前に、エチレン製造用クラッ
キングチューブ材料として好適な耐熱合金を提案した
(特公昭６３−４８９７参照)。この合金は、1100℃を超
える高温度域での使用において、すぐれた耐酸化性と耐
浸炭性を発揮する。その最大の理由は、このクラッキン
グチューブをかかる高温域で使用すると、チューブは高
温酸化作用を受けて、最も外側の表面部にＣｒ酸化物の
皮膜が形成され、この皮膜がバリヤーとなって材料の酸
化及び浸炭が防止されるためと考えられている。ところ
が、前記クラッキングチューブは、昇温及び降温のいわ
ゆる熱サイクルが繰り返されると、チューブの最外表面
に形成されたＣｒ酸化物皮膜がたやすく剥離してしまう
という問題が生じた。このＣｒ酸化物皮膜が剥離する
と、材料の重量減となるだけでなく、耐酸化性及び耐浸
炭性の劣化を招来することにもなる。The applicant has previously proposed a heat-resistant alloy suitable as a cracking tube material for ethylene production.
(See Japanese Examined Patent Publication No. 63-4897). This alloy exhibits excellent oxidation resistance and carburization resistance when used in the high temperature range above 1100 ° C. The main reason for this is that when this cracking tube is used in such a high temperature range, the tube is subjected to a high temperature oxidation action, and a Cr oxide film is formed on the outermost surface portion, and this film serves as a barrier for the material. It is believed that oxidation and carburization are prevented. However, the cracking tube has a problem that the Cr oxide film formed on the outermost surface of the tube easily peels off when a so-called thermal cycle of temperature increase and temperature decrease is repeated. When the Cr oxide film is peeled off, not only the weight of the material is reduced, but also the oxidation resistance and the carburization resistance are deteriorated.
【０００３】[0003]
【発明が解決しようとする課題】本発明の目的は、クラ
ッキングチューブ、リフォーミングチューブの如き合金
製品の最も外側表面部に形成されるＣｒ酸化物皮膜の密
着性を改善し、加熱・冷却の繰り返される苛酷な条件下
にあっても、合金材料の重量減を抑えると共に、すぐれ
た耐酸化性及び耐浸炭性を発揮させることにある。SUMMARY OF THE INVENTION An object of the present invention is to improve the adhesion of a Cr oxide film formed on the outermost surface of alloy products such as cracking tubes and reforming tubes so that heating and cooling can be repeated. It is to suppress the weight loss of the alloy material and to exert excellent oxidation resistance and carburization resistance even under severe conditions.
【０００４】[0004]
【課題を解決するための手段】上記目的を達成するため
に、本発明の合金は、重量％にて、Ｃ：０.１〜０.５
％、Ｓｉ：０.５〜３％、Ｍｎ：２％以下、Ｃｒ：３０
％を越えて４０％以下、Ｎｉ：４０％を越えて５５％以
下、Ｎｂ：０.３〜１.８％、Ａｌ：０.６％を超えて１.
０％未満、残部実質的にＦｅからなる。本発明の合金
は、必要に応じて、Ｔｉ：０.０２〜０.３％、Ｚｒ：
０.０２〜０.３％のいずれか１種又は２種を含んでい
る。In order to achieve the above object, the alloy of the present invention contains C: 0.1 to 0.5 in weight%.
%, Si: 0.5 to 3%, Mn: 2% or less, Cr: 30
% Over 40%, Ni: over 40% over 55%, Nb: 0.3-1.8%, Al: over 0.6% and 1.
Less than 0%, the balance consisting essentially of Fe. The alloy of the present invention, if necessary, Ti: 0.02 to 0.3%, Zr:
It contains any one or two of 0.02 to 0.3%.
【０００５】[0005]
【作用】上記Ｃｒ−Ｎｉ成分系合金に含まれるＡｌの含
有量を、０.６％を超えて１.０％未満としたことによ
り、チューブ表面近傍に安定なＡｌ2Ｏ3が生成する。こ
のＡｌ2Ｏ3は、チューブの最も外側に形成されるＣｒ酸
化物皮膜と親和性が強いため、Ｃｒ酸化物皮膜の密着性
を向上させることができる。従って、加熱と冷却が繰り
返される条件下でも、Ｃｒ酸化物皮膜は安定しており、
該皮膜の存在によって酸化の進行及びカーボンの材料内
部への拡散が防止され、すぐれた耐酸化性及び耐浸炭性
を具備することができる。When the content of Al contained in the Cr-Ni component alloy is set to more than 0.6% and less than 1.0%, stable Al 2 O 3 is produced in the vicinity of the tube surface. Since this Al 2 O 3 has a strong affinity with the Cr oxide film formed on the outermost side of the tube, the adhesion of the Cr oxide film can be improved. Therefore, the Cr oxide film is stable even under the condition of repeated heating and cooling,
Due to the presence of the coating, the progress of oxidation and the diffusion of carbon into the material are prevented, and excellent oxidation resistance and carburization resistance can be provided.
【０００６】[0006]
【発明の効果】加熱と冷却が繰り返される苛酷な条件下
での使用において、Ｃｒ酸化物の剥離が抑制されるた
め、材料の重量減を防止することができ、安定した操業
状態を確保することができる。また、1100℃を超える温
度域での使用において、すぐれた耐酸化性と耐浸炭性を
発揮するから、石油化学工業におけるエチレン製造用ク
ラッキングチューブや、リフォーミングチューブ等の材
料として好適である。EFFECT OF THE INVENTION In use under severe conditions where heating and cooling are repeated, peeling of Cr oxide is suppressed, so that weight loss of the material can be prevented and stable operation state can be secured. You can Further, since it exhibits excellent oxidation resistance and carburization resistance when used in a temperature range exceeding 1100 ° C., it is suitable as a material for a cracking tube for ethylene production in the petrochemical industry, a reforming tube and the like.
【０００７】[0007]
Ｃ：０.１〜０.５％ Ｃは鋳造の凝固時に結晶粒界にＣｒ、Ｎｂ等の炭化物を
形成する。また、オーステナイト相に固溶し、加熱によ
ってオーステナイト相にＣｒ炭化物を形成する。これら
炭化物の析出によってクリープ破断強度が向上する。こ
のため、少なくとも０.１％以上含有させる。しかし、
含有量が０.５％を超えるとＣｒ炭化物の分散析出量が
増え、時効後の延性の低下を招く。このため、上限は
０.５％とする。C: 0.1 to 0.5% C forms carbides such as Cr and Nb at crystal grain boundaries during solidification during casting. Further, it forms a solid solution in the austenite phase and forms Cr carbide in the austenite phase by heating. The precipitation of these carbides improves the creep rupture strength. Therefore, it is contained at least 0.1% or more. But,
If the content exceeds 0.5%, the amount of Cr carbide dispersed and precipitated increases, which leads to a decrease in ductility after aging. Therefore, the upper limit is 0.5%.
【０００８】Ｓｉ：０.５〜３％ Ｓｉは溶製時に、脱酸作用と共に溶鋼の流動性を向上さ
せる効果がある。また、Ｓｉの増加と共に、チューブ内
面の表面近傍にＳｉＯ2皮膜を形成し、Ｃの侵入を抑制
する耐浸炭効果がある。このため、少なくとも０.５％
以上含有させる。しかし、３％を超えるとクリープ破断
強度の低下及び溶接性の低下を招来するので上限を３％
とする。Si: 0.5-3% Si has the effect of deoxidizing the molten steel and improving the fluidity of the molten steel during melting. Further, as the amount of Si increases, a SiO 2 film is formed in the vicinity of the inner surface of the tube, which has a carburization resistance effect of suppressing C intrusion. Therefore, at least 0.5%
The above is contained. However, if it exceeds 3%, the creep rupture strength and weldability are deteriorated, so the upper limit is 3%.
And
【０００９】Ｍｎ：２％以下 ＭｎはＳｉと同様に脱酸剤として作用するほか、溶製中
のイオウを固定して溶接性を向上させる。しかし、２％
を超えて含有しても、それに対応する効果が得られない
ので、上限は２％とする。Mn: 2% or less Mn acts as a deoxidizing agent like Si, and fixes sulfur during melting to improve weldability. But 2%
Even if the content exceeds 5, the effect corresponding to it cannot be obtained, so the upper limit is 2%.
【００１０】Ｃｒ：３０％を越えて４０％以下 Ｃｒは耐酸化性及び高温強度を維持する上で不可欠の元
素である。1100℃を超える温度での使用において、チュ
ーブの外表面部にＣｒ酸化物の皮膜を形成して耐酸化性
を向上させる。また、この皮膜がバリヤーとなって浸炭
防止にもすぐれた効果を発揮する。このため、３０％を
越えて４０％以下の範囲で含有させる。Cr: more than 30% and 40% or less Cr is an essential element for maintaining oxidation resistance and high temperature strength. When used at temperatures above 1100 ° C, a film of Cr oxide is formed on the outer surface of the tube to improve oxidation resistance. In addition, this film acts as a barrier and exhibits an excellent effect in preventing carburization. For this reason, it is contained in the range of more than 30% and 40% or less.
【００１１】Ｎｉ：４０％を越えて５５％以下 Ｎｉはオーステナイト相を安定化させる元素であり、耐
酸化性と高温強度を高める効果を有する。1100℃を超え
る温度域での使用を考慮すると、４０％を越えて５５％
以下の範囲で含有させる。Ni: more than 40% and 55% or less Ni is an element that stabilizes the austenite phase, and has the effect of enhancing oxidation resistance and high temperature strength. Considering use in the temperature range over 1100 ° C, 55% over 40%
It is contained in the following range.
【００１２】Ｎｂ：０.３〜１.８％ Ｎｂは鋳造の凝固時に粒界にＮｂ炭化物を形成し、粒界
破壊抵抗を高め、クリープ破断強度を増大させる。この
ため、少なくとも０.３％以上含有させる。しかし、あ
まりに多く含有すると耐酸化性の低下を招くため、１.
８％を上限とする。Nb: 0.3 to 1.8% Nb forms Nb carbides at grain boundaries during solidification during casting, increases grain boundary fracture resistance, and increases creep rupture strength. Therefore, it is contained at least 0.3% or more. However, if it is contained too much, the oxidation resistance is lowered, so 1.
The upper limit is 8%.
【００１３】Ａｌ：０.６％を超えて１.０％未満 Ａｌは高温での使用中、チューブの表面近傍に安定なＡ
ｌ2Ｏ3を生成する。このＡｌ2Ｏ3は、Ｃｒ酸化物皮膜の
密着性を向上させる働きがある。従って、加熱と冷却が
繰り返される苛酷な条件下でも、チューブの最外表面に
形成されたＣｒ酸化物皮膜を安定に維持する効果があ
り、この皮膜とその内部に形成されるＡｌ2Ｏ3が酸化の
進行及びカーボンの材料内部への拡散を防止し、結果的
に耐酸化性及び耐浸炭性の向上に寄与する。含有量が
０.６％以下ではこの効果を発揮することができない。
また、１.０％以上含有すると、延性の低下が著しい。
このため、含有量は０.６％を超えて１.０％未満と規定
する。Al: more than 0.6% and less than 1.0% Al is stable A near the surface of the tube during use at high temperature.
l 2 O 3 is produced. This Al 2 O 3 has a function of improving the adhesion of the Cr oxide film. Therefore, even under severe conditions where heating and cooling are repeated, the Cr oxide film formed on the outermost surface of the tube has an effect of being stably maintained, and this film and the Al 2 O 3 formed inside the film have an effect. It prevents the progress of oxidation and the diffusion of carbon into the material, and consequently contributes to the improvement of oxidation resistance and carburization resistance. If the content is 0.6% or less, this effect cannot be exhibited.
Further, when the content is 1.0% or more, the ductility is remarkably reduced.
Therefore, the content is defined as more than 0.6% and less than 1.0%.
【００１４】本発明の耐熱合金は上記の成分元素を含有
し、残部は不可避的に混入するＰ、Ｓその他の不純物元
素及びＦｅからなる。The heat-resistant alloy of the present invention contains the above-mentioned constituent elements, and the balance is Fe, which is unavoidably mixed, and other impurity elements such as P and Fe.
【００１５】また、本発明の耐熱合金は、必要に応じ
て、以下に記載する成分元素の１種又は２種を含有させ
ることができる。The heat-resistant alloy of the present invention may contain one or two of the following component elements, if necessary.
【００１６】Ｔｉ：０.０２〜０.３％ Ｔｉはチューブとして高温で使用時、オーステナイト相
中に生成するＣｒ炭化物の成長粗大化を遅延させ、クリ
ープ破断強度の向上に寄与する。この効果を得るために
は、０.０２％以上含有させることが望ましい。しか
し、あまりに多く含有すると、析出物の粗大化、一次炭
化物の分断化により、強度の低下を招くので０.３％を
上限とする。Ti: 0.02 to 0.3% Ti delays the growth coarsening of Cr carbide formed in the austenite phase when used as a tube at high temperature, and contributes to the improvement of creep rupture strength. In order to obtain this effect, it is desirable to contain 0.02% or more. However, if the content is too large, the precipitates become coarse and the primary carbides are fragmented, resulting in a decrease in strength. Therefore, the upper limit is 0.3%.
【００１７】Ｚｒ：０.０２〜０.３％ Ｚｒはチューブとして高温で使用時、オーステナイト相
中に生成するＣｒ炭化物の成長粗大化を遅延させ、クリ
ープ破断強度の向上に寄与する。この効果を得るために
は、０.０２％以上含有させることが望ましい。しか
し、あまり多く含有すると、析出物の粗大化、一次炭化
物の分断化により、強度の低下を招くので０.３％を上
限とする。Zr: 0.02 to 0.3% Zr delays the growth coarsening of Cr carbide formed in the austenite phase when used as a tube at high temperature, and contributes to the improvement of creep rupture strength. In order to obtain this effect, it is desirable to contain 0.02% or more. However, if contained too much, coarsening of precipitates and fragmentation of primary carbides lead to a decrease in strength, so the upper limit is 0.3%.
【００１８】[0018]
【実施例】高周波誘導溶解炉で各種成分の合金を溶製
し、遠心鋳造にて鋳塊を製造した。各供試材の化学成分
組成を表１に示す。表１において、供試No.１〜No.４
は、本発明の実施例、No.５及びNo.６は、比較例であ
る。比較例のうち、No.５はＣｒ、Ｎｉ及びＡｌが本発
明合金の範囲から逸脱しており、No.６はＡｌが本発明
合金の範囲から逸脱している。[Examples] Alloys of various components were melted in a high frequency induction melting furnace, and ingots were manufactured by centrifugal casting. Table 1 shows the chemical composition of each test material. In Table 1, test No. 1 to No. 4
Is an example of the present invention, and Nos. 5 and 6 are comparative examples. Among the comparative examples, No. 5 is out of the range of the alloy of the present invention in Cr, Ni and Al, and No. 6 is out of the range of the alloy of the present invention in Al.
【００１９】[0019]
【表１】 [Table 1]
【００２０】各供試材から試験片(厚さ15mm、幅25mm、
長さ70mm)を作製し、浸炭試験を行なった。浸炭は、試
験片と固体浸炭剤を詰めた筒状の容器を加熱炉に入れ、
図１に示す条件にて７回(48時間×7回＝336時間)繰り返
して実施した。処理後、試験片の表面から0.5mmピッチ
で切粉を採取し、切粉を化学分析してカーボンの増加量
を調べた。その結果を図２に示す。Test pieces from each test material (thickness 15 mm, width 25 mm,
A length of 70 mm was prepared and a carburization test was performed. Carburizing involves placing a cylindrical container filled with a test piece and a solid carburizing agent in a heating furnace.
It was repeated 7 times (48 hours × 7 times = 336 hours) under the conditions shown in FIG. After the treatment, chips were collected from the surface of the test piece at a pitch of 0.5 mm, and the chips were chemically analyzed to examine the increase amount of carbon. The result is shown in FIG.
【００２１】図２から明らかなように、本発明の実施例
である供試No.１〜No.４は、比較例No.５、No.６と比べ
てカーボンの増加量が遥かに少なく、耐浸炭性、特に昇
温と降温が繰り返される条件下における耐浸炭性にすぐ
れていることがわかる。特に表面から約１mm深さ部分ま
でのカーボン増加量に関しては、本発明例は比較例の約
1/4乃至1/6程度であり、極めて少ないといえる。また、
この浸炭防止効果は、Ａｌ2Ｏ3の形成に依るところが大
きいと考えられる。このＡｌ2Ｏ3は、Ｃｒ酸化物皮膜の
密着性を向上させるから、昇温と降温が繰り返される条
件下において、すぐれた耐酸化性を備えることにもな
る。As is apparent from FIG. 2, the samples Nos. 1 to 4 which are the examples of the present invention have much less carbon increase than the comparative examples No. 5 and No. 6, It can be seen that the carburization resistance is excellent, especially the carburization resistance under the condition that the temperature is raised and lowered repeatedly. Especially, regarding the amount of carbon increase from the surface to the depth of about 1 mm, the present invention example is about
It is about 1/4 to 1/6, which can be said to be extremely small. Also,
It is considered that this carburizing prevention effect largely depends on the formation of Al 2 O 3 . Since this Al 2 O 3 improves the adhesion of the Cr oxide film, it also has excellent oxidation resistance under conditions in which the temperature is raised and lowered repeatedly.
【図１】浸炭試験の浸炭加熱条件(温度と時間)を説明す
る図である。FIG. 1 is a diagram illustrating carburizing heating conditions (temperature and time) in a carburizing test.
【図２】浸炭試験におけるＣ増加量を示すグラフであ
る。FIG. 2 is a graph showing the amount of C increase in a carburizing test.
Claims (2)
ｉ：０.５〜３％、Ｍｎ：２％以下、Ｃｒ：３０％を越
えて４０％以下、Ｎｉ：４０％を越えて５５％以下、Ｎ
ｂ：０.３〜１.８％、Ａｌ：０.６％を超えて１.０％未
満、残部実質的にＦｅからなる耐浸炭性及び耐酸化性に
すぐれる耐熱合金。1. C: 0.1-0.5%, S by weight%
i: 0.5-3%, Mn: 2% or less, Cr: more than 30% and 40% or less, Ni: more than 40% and 55% or less, N
b: 0.3 to 1.8%, Al: more than 0.6% and less than 1.0%, the balance being substantially Fe, which is a heat-resistant alloy having excellent carburization resistance and oxidation resistance.
２〜０.３％のいずれか１種又は２種を含んでいる請求
項１に記載の耐熱合金。2. Ti: 0.02 to 0.3%, Zr: 0.0
The heat-resistant alloy according to claim 1, containing any one or two of 2 to 0.3%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31648893A JPH07166290A (en) | 1993-12-16 | 1993-12-16 | Heat resistant alloy excellent in carburization resistance and oxidation resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31648893A JPH07166290A (en) | 1993-12-16 | 1993-12-16 | Heat resistant alloy excellent in carburization resistance and oxidation resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07166290A true JPH07166290A (en) | 1995-06-27 |
Family
ID=18077658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31648893A Withdrawn JPH07166290A (en) | 1993-12-16 | 1993-12-16 | Heat resistant alloy excellent in carburization resistance and oxidation resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07166290A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5866068A (en) * | 1995-09-29 | 1999-02-02 | Kubota Corporation | Heat-resistant alloy |
| WO1999009230A1 (en) * | 1997-08-20 | 1999-02-25 | Jgc Corporation | Heating furnace tube, method of using the same, and method of manufacturing the same |
| CN105271228A (en) * | 2014-06-19 | 2016-01-27 | 上海梅山钢铁股份有限公司 | Method and device used for preventing clinkering-up of CO generator |
-
1993
- 1993-12-16 JP JP31648893A patent/JPH07166290A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5866068A (en) * | 1995-09-29 | 1999-02-02 | Kubota Corporation | Heat-resistant alloy |
| WO1999009230A1 (en) * | 1997-08-20 | 1999-02-25 | Jgc Corporation | Heating furnace tube, method of using the same, and method of manufacturing the same |
| AU733795B2 (en) * | 1997-08-20 | 2001-05-24 | Jgc Corporation | Heating furnace tube, method of using the same, and method of manufacturing the same |
| AU733795C (en) * | 1997-08-20 | 2002-02-07 | Jgc Corporation | Heating furnace tube, method of using the same, and method of manufacturing the same |
| US6514631B1 (en) * | 1997-08-20 | 2003-02-04 | Jgc Corporation | Heating furnace tube and method of manufacturing the same |
| KR100509290B1 (en) * | 1997-08-20 | 2005-08-18 | 닛끼 가부시끼가이샤 | Heating furnace tube, method of using the same, and method of manufacturing the same |
| CN105271228A (en) * | 2014-06-19 | 2016-01-27 | 上海梅山钢铁股份有限公司 | Method and device used for preventing clinkering-up of CO generator |
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