JP2970432B2 - High temperature stainless steel and its manufacturing method - Google Patents
High temperature stainless steel and its manufacturing methodInfo
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- JP2970432B2 JP2970432B2 JP6260613A JP26061394A JP2970432B2 JP 2970432 B2 JP2970432 B2 JP 2970432B2 JP 6260613 A JP6260613 A JP 6260613A JP 26061394 A JP26061394 A JP 26061394A JP 2970432 B2 JP2970432 B2 JP 2970432B2
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- temperature
- creep
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、高温環境下での使用に
おいて優れた特性を示す溶接性に優れたオーステナイト
系ステンレス鋼とその製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an austenitic stainless steel exhibiting excellent properties when used in a high-temperature environment and having excellent weldability, and a method for producing the same.
【０００２】[0002]
【従来の技術】特に近年に至り、地球環境保全の観点か
ら各種排出ガス中のNOx 、SOx 、CO2等の有害ガスの濃
度低減が強く要望されている。一方、従来より、化石エ
ネルギー資源の有効活用の面から効率的なエネルギー利
用の必要性が強調されてきている。Reaches the Related Art In recent years, NOx in the perspective various emissions from a gas to protect the global environment, SOx, the concentration reduction of harmful gases such as CO 2 have been strongly desired. On the other hand, the necessity of efficient energy use has been emphasized from the viewpoint of effective use of fossil energy resources.
【０００３】これら両者の要望を満足するために、火力
発電、化学工業あるいは鉄鋼製造などの各技術分野では
より高温での操業が必要となってきている。そして、そ
れらの高温装置用材料には耐酸化性、耐摩耗性および耐
クリープ特性等の高温特性および溶接性に優れることが
要求される。In order to satisfy both of these demands, it is necessary to operate at higher temperatures in various technical fields such as thermal power generation, chemical industry, and steel production. These materials for high-temperature equipment are required to be excellent in high-temperature properties such as oxidation resistance, wear resistance and creep resistance and in weldability.
【０００４】従来、このような高温用途には、オーステ
ナイト系ステンレス鋼が多く用いられている。例えば、
SUS304に代表される18Cr−８Ni系、SUS310S を代表とす
る25Cr−20Ni系、Alloy 800 として知られる20Cr−32Ni
鋼等の高Cr−高Ni鋼がある。また、高Si化により高温特
性の向上を図ったステンレス鋼としては、AlSI302B、JI
SXM15J1 、AISI314 鋼等が知られている。その他、高温
特性を改善したステンレス鋼としては、特開昭52−4418
号、特公昭53−43370 号、同54−12890 号、同54−3320
7 号、同56−17424 号、同56−25507 号、同57−16187
号、同57−42701 号、同57−54543 号、同57−59299
号、同58−2268号、同58−42264 号、特開昭59−185763
号、同60−92454 号、同63−69949 号、同63−213643
号、同63−69950 号、同63−69951 号、同63−157840
号、同63−213643号、特公昭64−8695号、特開平１−15
9351号等が開示されている。Conventionally, austenitic stainless steels are often used for such high temperature applications. For example,
18Cr-8Ni system represented by SUS304, 25Cr-20Ni system represented by SUS310S, 20Cr-32Ni known as Alloy 800
There is a high Cr-high Ni steel such as steel. Also, stainless steels with improved high-temperature characteristics by increasing the Si content include AlSI302B, JI
SXM15J1, AISI314 steel and the like are known. Other stainless steels with improved high-temperature properties include Japanese Patent Application Laid-Open No. 52-4418.
No. 53-43370, No. 54-12890, No. 54-3320
No. 7, No. 56-17424, No. 56-25507, No. 57-16187
Nos. 57-42701, 57-54543, 57-59299
No. 58-2268, No. 58-42264, JP-A-59-185763
Nos. 60-92454, 63-69949, 63-213643
Nos. 63-69950, 63-69951, 63-157840
No. 63-213643, JP-B 64-8695, JP-A 1-15
No. 9351 is disclosed.
【０００５】これらの特許における高温特性の改善は、
Si含有量の増加により達成されるものが多く、その他、
Mo、Cu、Ｎ、Ti、Nb等の元素を添加することにより達成
されるものもある。The improvement in high temperature properties in these patents is:
Many are achieved by increasing the Si content.
Some are achieved by adding elements such as Mo, Cu, N, Ti, and Nb.
【０００６】例えば、特開昭63−69949 号公報開示のオ
ーステナイト系ステンレス鋼は、厳しい加工を加えて
も、優れた非磁性を維持し得ることを目的にしており、
組成上はオーステナイト安定化のためCu添加が必須であ
り、Al添加は行われていない。また、非磁性ということ
でクリープ特性等の高温性能については何ら明らかにさ
れていない。Cuは800 ℃以上の温度域ではクリープ強度
向上への寄与は見られず、クリープ延性は低下する。ま
た、Niバランスについても何ら考慮されていない。For example, an austenitic stainless steel disclosed in Japanese Patent Application Laid-Open No. 63-69949 is intended to be able to maintain excellent non-magnetism even under severe processing.
In terms of composition, Cu addition is essential for stabilizing austenite, and Al addition is not performed. In addition, high temperature performance such as creep characteristics is not disclosed at all because it is non-magnetic. Cu does not contribute to the improvement of creep strength in the temperature range of 800 ° C or higher, and the creep ductility decreases. Also, no consideration is given to the Ni balance.
【０００７】特開昭63−69951 号公報開示のものも上述
と同様であり、この場合、Al：0.05〜1.0 ％の存在が許
容されるが、これはTi、Ｖ、Nbの均等物として結晶粒微
細化効果を発揮する元素として利用されており、実施例
におけるAl添加鋼は0.5 ％以上の多量添加が行われてい
る。The structure disclosed in Japanese Patent Application Laid-Open No. 63-69951 is also the same as described above. In this case, the presence of Al: 0.05 to 1.0% is permitted. It is used as an element exhibiting a grain refining effect, and the Al-added steel in the examples is added in a large amount of 0.5% or more.
【０００８】特開昭63−157840号公報に開示のオーステ
ナイト系ステンレス鋼では熱間加工性の改善を目的にデ
ルタフェライトを10〜20％に規定しており、実施例中の
鋼のNiバランスは−1.9 〜−3.4(本願中の式で計算) と
なる。また、Al含有量および高温特性については何一つ
明らかにすることがない。In the austenitic stainless steel disclosed in Japanese Patent Application Laid-Open No. 63-157840, delta ferrite is specified to be 10 to 20% for the purpose of improving hot workability. −1.9 to −3.4 (calculated by the formula in the present application). In addition, nothing is disclosed about the Al content and the high temperature characteristics.
【０００９】しかも、18Cr−８Ni系は溶接性および経済
性に優れるものの、耐酸化性等の高温特性が劣る。高Cr
−高Ni鋼および高Si系鋼は耐酸化性には優れるものの、
クリープ特性および溶接性に問題がある。さらに、その
高Cr−高Ni鋼は、高価なNiを多量に使用するため経済性
の面からの問題もある。Moreover, although 18Cr-8Ni is excellent in weldability and economy, it is inferior in high-temperature properties such as oxidation resistance. High Cr
−High Ni steel and high Si steel have excellent oxidation resistance,
There is a problem in creep characteristics and weldability. Further, the high Cr-high Ni steel has a problem in terms of economy because a large amount of expensive Ni is used.
【００１０】[0010]
【発明が解決しようとする課題】ここに、本発明の目的
は、高温の耐酸化性、耐摩耗性およびクリープ特性が優
れ、かつ、溶接性の優れた安価なオーステナイト系ステ
ンレス鋼とその製造方法を提供することである。SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive austenitic stainless steel excellent in high-temperature oxidation resistance, abrasion resistance and creep characteristics, and excellent in weldability, and a method for producing the same. It is to provide.
【００１１】[0011]
【課題を解決するための手段】よって、本発明の要旨と
するところは、重量％で Ｃ:0.05 〜0.15％、Si:1.0％未満、Mn:2.0％以下、Ｐ:
0.04 ％以下、Ｓ:0.01 ％以下、Cr: 20〜30％、Ni:10
〜15％、Ｎ:0.10 〜0.30％、Ｂ:0.0010 〜0.01％、La＋
Ce: 0.01〜0.10％、Al: 0.01〜0.20％、残部実質的にFe
および不可避的不純物 より成り、下記式で示されるNiバランス値が−1.0 ％〜
＋3.0 ％の範囲にあることを特徴とする溶接性に優れた
高温用オーステナイト系ステンレス鋼である。Accordingly, the gist of the present invention is that the following are weight percentages: C: 0.05 to 0.15%, Si: less than 1.0%, Mn: 2.0% or less, P:
0.04% or less, S: 0.01% or less, Cr: 20 to 30%, Ni: 10
~ 15%, N: 0.10 ~ 0.30%, B: 0.0010 ~ 0.01%, La +
Ce: 0.01 to 0.10%, Al: 0.01 to 0.20%, balance substantially Fe
And unavoidable impurities, and the Ni balance value represented by the following formula is −1.0% or more.
High-temperature austenitic stainless steel with excellent weldability characterized by being in the range of + 3.0%.
【００１２】Niバランス値 (重量%)＝%Ni+0.5×%Mn+30
×(%C+%N)−1.1×(%Cr+1.5×%Si)＋8.2・・・式(1) また本発明は、重量％で Ｃ:0.05 〜0.15％、 Si:1.0％未満、 Mn:2.0％以
下、Ｐ:0.04 ％以下、 Ｓ:0.01 ％以下、 Cr: 20
〜30％、Ni:10 〜15％、 Ｎ:0.10 〜0.30％、
Ｂ:0.0010 〜0.01％、La＋Ce: 0.01〜0.10％、Al: 0.01
〜0.20％を含み、かつＮとAlが次式を満足する量で含有
し、 Ｎ(%) ＋２Al(%) ≦0.500% ・・・式(2) 残部実質的にFeおよび不可避的不純物 より成る鋼組成を有することを特徴とする溶接性に優れ
た高温用オーステナイト系ステンレス鋼である。Ni balance value (% by weight) =% Ni + 0.5 ×% Mn + 30
× (% C +% N) −1.1 × (% Cr + 1.5 ×% Si) +8.2 (1) In the present invention, C: 0.05 to 0.15% by weight%, Si: less than 1.0%, Mn: 2.0% or less, P: 0.04% or less, S: 0.01% or less, Cr: 20
~ 30%, Ni: 10 ~ 15%, N: 0.10 ~ 0.30%,
B: 0.0010 to 0.01%, La + Ce: 0.01 to 0.10%, Al: 0.01
0.20.20%, and N and Al are contained in amounts satisfying the following formula: N (%) + 2Al (%) ≦ 0.500% ・ ・ ・ Formula (2) The balance substantially consists of Fe and unavoidable impurities It is an austenitic stainless steel for high temperature that is excellent in weldability and has a steel composition.
【００１３】本発明はその別の面からは、上記鋼組成の
鋼に対し、分塊圧延前に1150〜1350℃の温度範囲で２時
間以上ソーキング処理を行った後、分塊圧延、熱間圧
延、および焼鈍処理を行うことを特徴とする溶接性に優
れた高温用オーステナイト系ステンレス鋼の製造方法で
ある。In another aspect of the present invention, a steel having the above steel composition is subjected to a soaking treatment in a temperature range of 1150 to 1350 ° C. for 2 hours or more before the slab rolling, followed by slab rolling and hot working. This is a method for producing a high-temperature austenitic stainless steel excellent in weldability, characterized by performing rolling and annealing.
【００１４】[0014]
【作用】以下に本発明における鋼組成およびNiバランス
値、ならびに製造条件の限定理由について述べる。The reasons for limiting the steel composition and the Ni balance value in the present invention and the manufacturing conditions are described below.
【００１５】Ｃ:オーステナイト組織の安定化を促進す
るとともにクリープ強度を高めるのに有効な元素である
が、Ｃ:0.05 ％未満ではその効果を発揮し得ず、含有量
が0.15％を超えると熱間加工性が阻害されるのでその範
囲を0.05％以上、0.15％以下とする。C: an element effective for promoting the stabilization of the austenite structure and increasing the creep strength. However, if the content of C is less than 0.05%, the effect cannot be exerted. Since the workability is impaired, the range is set to 0.05% or more and 0.15% or less.
【００１６】Si:溶解時の脱酸成分であるが添加量の増
加とともに溶接性およびクリープ強度の劣化が著しくな
るのでその範囲を1.0 ％未満とする。好ましくは0.4 ％
以下である。Si: A deoxidizing component at the time of dissolution, however, the weldability and the creep strength deteriorate remarkably as the amount of addition increases, so the range is set to less than 1.0%. Preferably 0.4%
It is as follows.
【００１７】Mn:Si と同様、脱酸成分であるとともにオ
ーステナイト組織の安定化に有効であるが多量の添加は
耐酸化性を劣化させるので上限2.0 ％とする。好ましく
は1.0 ％以下である。さらに好ましくはMn:0.5％未満で
ある。Like Mn: Si, it is a deoxidizing component and is effective in stabilizing the austenite structure. However, since the addition of a large amount deteriorates the oxidation resistance, the upper limit is set to 2.0%. Preferably it is 1.0% or less. More preferably, Mn is less than 0.5%.
【００１８】Ｐ:溶接性およびクリープ強度の面から少
ない方が望ましいが製造性と経済性とを考慮して上限を
0.04％とする。P: It is desirable that the amount is small in terms of weldability and creep strength, but the upper limit is taken into consideration in consideration of manufacturability and economy.
0.04%.
【００１９】Ｓ:Ｐと同様に溶接性およびクリープ強度
を阻害する元素であり少ない方が望ましいが製造性と経
済性を考慮して0.01％以下とする。S: Similar to P, it is an element that inhibits weldability and creep strength, and it is desirable that the content be small. However, the content is made 0.01% or less in consideration of manufacturability and economy.
【００２０】Cr:耐酸化性、耐高温摩耗性およびクリー
プ強度の向上に有効な元素であるが、20％未満ではその
効果が小さく、30％を超える添加はオーステナイト組織
の安定化を阻害するとともに熱間加工性を劣化させるの
でその範囲を20％以上、30％以下とする。好ましくは21
〜25％である。Cr: an element effective for improving oxidation resistance, high-temperature wear resistance and creep strength, the effect is small when it is less than 20%, and when added more than 30%, it hinders the stabilization of the austenite structure and Since the hot workability is degraded, the range is set to 20% or more and 30% or less. Preferably 21
~ 25%.
【００２１】Ni:オーステナイト組織の安定化および耐
酸化性、クリープ強度の向上において重要な元素である
が、10％未満ではその効果が小さく、他方15％を超える
添加は溶接性を阻害するのでその範囲を10％以上、15％
以下とする。好ましくは10〜13％である。Ni: an important element in stabilizing the austenite structure and improving oxidation resistance and creep strength. If less than 10%, its effect is small, and if it exceeds 15%, the weldability is impaired. Range over 10%, 15%
The following is assumed. Preferably it is 10 to 13%.
【００２２】Ｎ:オーステナイト組織の安定化およびク
リープ強度の向上に有効な元素であるが、0.10％未満で
はクリープ強度の向上に寄与せず、0.30％を超える添加
は熱間加工性を阻害するのでその範囲を0.10％以上、0.
30％以下とする。N: An element effective for stabilizing the austenite structure and improving the creep strength. However, if it is less than 0.10%, it does not contribute to the improvement of the creep strength, and if it exceeds 0.30%, the hot workability is impaired. The range is 0.10% or more, 0.
30% or less.
【００２３】Ｂ:クリープ強度および熱間加工性の向上
に有効な元素であり、0.0010％以上でその効果を発揮す
る。0.01％を超える添加はかえって熱間加工性を阻害す
るので、その範囲を0.0010％以上、0.01％以下とする。B: An element effective for improving creep strength and hot workability, and exerts its effect at 0.0010% or more. Addition exceeding 0.01% rather impairs hot workability, so the range is made 0.0010% or more and 0.01% or less.
【００２４】La＋Ce:耐酸化性および耐高温摩耗性向上
に有効な元素であるが、0.01％未満ではその効果を発揮
し得ず、0.10％を超える添加は熱間加工性および溶接性
を阻害するのでその範囲を0.01％以上、0.10％以下とす
る。なお、La＋Ceはミッシュメタルとして添加されるの
であって、両者の割合は特に制限されない。La + Ce: an element effective for improving oxidation resistance and high-temperature wear resistance, but if less than 0.01%, the effect cannot be exhibited, and if added more than 0.10%, hot workability and weldability are impaired. Therefore, the range is set to 0.01% or more and 0.10% or less. Note that La + Ce is added as a misch metal, and the ratio of both is not particularly limited.
【００２５】Al:La＋Ceの添加効果を発揮させるための
脱酸成分として0.01％以上の添加が必要である。多量の
添加は溶接性およびクリープ特性を悪化させるので上限
を0.20％とする。好ましくは上限は0.10％である。It is necessary to add 0.01% or more as a deoxidizing component in order to exert the effect of adding Al: La + Ce. Since the addition of a large amount deteriorates the weldability and creep characteristics, the upper limit is made 0.20%. Preferably the upper limit is 0.10%.
【００２６】Niバランス値:前述の式(1) で規定されるN
iバランス値は冶金学的にはオーステナイト組織の安定
性を意味するが、Niバランス値が小さくなると高温でσ
相等の金属間化合物が析出し易くなりクリープ強度を低
下させる。他方、Niバランス値が大きくなると溶接性を
悪化させる。高温特性および溶接性の両面から、Niバラ
ンス値の範囲を−1.0 ％以上、＋3.0 ％以下とする。好
ましくはNiバランス値は0.0 〜＋2.0％である。Ni balance value: N defined by the above equation (1)
Metallurgically, the i-balance value means the stability of the austenitic structure.
Intermetallic compounds such as phases are likely to precipitate and lower the creep strength. On the other hand, as the Ni balance value increases, the weldability deteriorates. From the viewpoint of both high-temperature characteristics and weldability, the range of the Ni balance value is set to −1.0% or more and + 3.0% or less. Preferably, the Ni balance value is 0.0 to + 2.0%.
【００２７】Ｎ(%) ＋２Al(%) ≦0.500 ％・・・(2) AlおよびＮは多量添加により溶体化時に未凝固AlN とし
て鋼中に残存し、クリープ破断強度および延性、靱性の
低下を引き起こす。そのため高温強度を向上させるため
にはAl、Ｎが前記式(2) を満足する範囲で添加する必要
がある。N (%) + 2Al (%) ≦ 0.500% (2) Al and N remain in the steel as unsolidified AlN at the time of solution treatment due to the addition of a large amount, and decrease in creep rupture strength, ductility and toughness. cause. Therefore, in order to improve the high temperature strength, it is necessary to add Al and N in a range satisfying the above formula (2).
【００２８】製造方法：1150〜1350℃の温度範囲におけ
るソーキング処理は、大型鋼塊凝固時の成分偏析を緩和
し、製品の高温での使用時におけるクリープ特性の改善
を図るためである。この効果を発揮させるためには、前
記温度範囲において少なくとも２時間以上の加熱が必要
である。Manufacturing method: The soaking treatment in the temperature range of 1150 to 1350 ° C. is intended to alleviate the segregation of components during solidification of large ingots and to improve the creep characteristics of the product when used at high temperatures. In order to exhibit this effect, heating for at least 2 hours or more in the above temperature range is required.
【００２９】ソーキング後に、分塊圧延、熱間圧延を行
なうが、これらは目的に応じて例えば慣用法に準じて行
えばよく、本発明においても特に制限はない。焼鈍処理
は、例えば1100〜1200℃×２時間保持後、水冷して行え
ばよいが、これによって結晶組織の整粒化が達成される
のであり、その限りにおいて特に制限はない。After soaking, block rolling and hot rolling are performed. These may be performed according to a purpose, for example, according to a conventional method, and there is no particular limitation in the present invention. The annealing treatment may be performed, for example, by holding at 1100 to 1200 ° C. for 2 hours and then cooling with water. However, the grain size of the crystal structure is achieved, and there is no particular limitation.
【００３０】[0030]
【実施例】本発明の実施例を以下に示す。 (実施例１)表１に本発明鋼および比較鋼の化学組成 (重
量％、残部はFe) を示す。これらの試料は高周波電気炉
(真空溶解) で溶解した25kg鋼塊を鍛造、熱間圧延、焼
鈍を施して得た。Embodiments of the present invention will be described below. (Example 1) Table 1 shows the chemical compositions (% by weight, the balance being Fe) of the steels of the present invention and comparative steels. These samples were taken from a high-frequency electric furnace.
A 25 kg steel ingot melted by (vacuum melting) was obtained by forging, hot rolling and annealing.
【００３１】表２は表１に示した本発明鋼と一部の比較
鋼についての酸化試験結果を示す。試験は大気中、1100
℃で24時間加熱→室温冷却を５回繰り返す方法で行い試
験前後の試験片重量変化で評価した。酸化減量50 g/m2
以下を合格とした。本発明鋼の酸化減量はいずれも50 g
/m2 以下であり優れた耐酸化性を示している。Table 2 shows the oxidation test results for the steel of the present invention shown in Table 1 and some comparative steels. Test is in air, 1100
The procedure of heating at room temperature for 24 hours and then cooling to room temperature was repeated five times, and the evaluation was made based on the change in weight of the test piece before and after the test. Oxidation weight loss 50 g / m 2
The following were accepted. The oxidation loss of the steel of the present invention is 50 g
/ m 2 or less, indicating excellent oxidation resistance.
【００３２】表３は表１に示した本発明鋼と一部の比較
鋼についての高温摩耗試験結果を示す。試験は大気中、
700 ℃で人造硅砂を吹き付ける方法で行った。試験時間
は３時間とし、人造硅砂の吹付け濃度 (アッシュ濃度)
は20mg/m3 とした。減肉深さ15μm 以下を合格とした。Table 3 shows the results of the high temperature wear test for the steel of the present invention shown in Table 1 and some comparative steels. The test was in air,
At 700 ° C, artificial silica sand was sprayed. The test time is 3 hours, and the spray concentration of artificial silica sand (ash concentration)
Was set to 20 mg / m 3 . A thickness reduction depth of 15 μm or less was considered acceptable.
【００３３】試験後の本発明鋼の減肉深さはいずれも10
μｍ程度と比較鋼よりも浅く、優れた耐高温摩耗性を示
している。表２および表３の結果から分かるように、比
較鋼においては高SiのNo.18 鋼および高Crで高NiのNo.2
2 鋼は比較的良好な耐酸化性および耐摩耗性を示すもの
の、その他の鋼はいずれも劣っている。After the test, the thickness of the steel of the present invention was 10
It is about μm, which is shallower than the comparative steel, and shows excellent high-temperature wear resistance. As can be seen from the results in Tables 2 and 3, the comparative steels were No. 18 steels with high Si and No. 2 steels with high Cr and high Ni.
2 Steels show relatively good oxidation and wear resistance, but all other steels are inferior.
【００３４】表４は表１に示した本発明鋼と一部の比較
鋼について900 ℃で3.5kgf/mm2におけるクリープ・ラプ
チャー試験結果を示す。破断時間250 時間以上を合格と
した。本発明鋼はいずれもクリープ破断時間がかなり長
時間側にあり、優れた耐クリープ特性を示すことがわか
る。Table 4 shows the results of a creep rupture test at 3.5 ° C / mm 2 at 900 ° C. for the steel of the present invention shown in Table 1 and some comparative steels. A rupture time of 250 hours or more was regarded as acceptable. It can be seen that all the steels of the present invention have a considerably long creep rupture time and exhibit excellent creep resistance.
【００３５】表５は表１に示した本発明鋼と比較鋼につ
いてのトランスバレストレイン試験による溶接高温割れ
感受性の調査結果を示す。歪量は２％とした。最大割れ
長さ0.25mm以下を合格とした。Table 5 shows the results of investigation on the hot cracking susceptibility of the steels of the present invention and the comparative steels shown in Table 1 by the Transvarestraint test. The amount of distortion was 2%. The maximum crack length of 0.25 mm or less was judged to be acceptable.
【００３６】本発明鋼はほとんど割れを示さず優れた耐
溶接高温割れ感受性を示している。他方、比較鋼ではい
ずれも大きな最大割れ長さを示しており、溶接高温割れ
感受性の高いことが示される。The steel of the present invention shows almost no cracking and exhibits excellent resistance to hot cracking at welding. On the other hand, all of the comparative steels show a large maximum crack length, indicating that the welding hot cracking susceptibility is high.
【００３７】比較鋼においては耐酸化性および耐摩耗性
が比較的良好であったNo.18 鋼およびNo.22 鋼はいずれ
も耐クリープ性および耐溶接高温割れ感受性が本発明鋼
よりも劣っていることが示される。In the comparative steels, both the No. 18 steel and the No. 22 steel, which had relatively good oxidation resistance and wear resistance, were inferior in creep resistance and susceptibility to welding hot cracking compared to the steel of the present invention. Is shown.
【００３８】次に、図１は表４および表５の結果にもと
づいて900 ℃で3.5 kgf/mm2 の応力を負荷したクリープ
・ラプチャー試験における破断時間および肉厚４mmの10
0 mm角の試験片を用い、100 Ａ、14Ｖ、送り速度15 cm/
min の溶接条件で試験片表面をTIG 溶接し、その直後に
曲げ歪 (歪量２％) を与えるトランスバレストレイン試
験における最大割れ長さについてNiバランス値で整理し
た図である。図中の各No. は表１における試料No. を示
す。Next, FIG. 1 shows the results of Tables 4 and 5 showing the results of the creep rupture test under a load of 3.5 kgf / mm 2 at 900 ° C.
Using a test piece of 0 mm square, 100 A, 14 V, feed rate 15 cm /
FIG. 5 is a diagram in which the maximum crack length in a transvarestrain test in which a test piece surface is TIG-welded under a welding condition of min and a bending strain (strain amount of 2%) is given immediately thereafter is arranged by Ni balance values. Each number in the figure indicates the sample number in Table 1.
【００３９】図示結果からも分かるように、クリープ破
断時間はNiバランス量が−１％未満で急激に低下する。
また溶接最大割れ長さはNiバランス値が３％を超えると
急激に増大する。すなわち、本発明における成分範囲内
でクリープ特性および溶接性の両者を満足するNiバラン
ス値の範囲は−１〜＋３％にあることが分かる。As can be seen from the illustrated results, the creep rupture time sharply decreases when the Ni balance amount is less than -1%.
Further, the maximum weld crack length rapidly increases when the Ni balance value exceeds 3%. That is, it can be seen that the range of the Ni balance value that satisfies both the creep characteristics and the weldability within the component range in the present invention is -1 to + 3%.
【００４０】[0040]
【表１】 [Table 1]
【００４１】[0041]
【表２】 [Table 2]
【００４２】[0042]
【表３】 [Table 3]
【００４３】[0043]
【表４】 [Table 4]
【００４４】[0044]
【表５】 [Table 5]
【００４５】(実施例２)本例では、表６に示す化学組成
の鋼 (重量％、残部はFe) を製造規模で溶製、真空精錬
後、８トン鋼塊として造塊した。造塊後、ソーキング処
理を実施した鋼塊および未実施鋼塊を分塊圧延、熱間圧
延、焼鈍を施した。Example 2 In this example, steel (weight%, balance Fe) having the chemical composition shown in Table 6 was melted on a production scale, vacuum refined, and then ingoted as an 8-ton steel ingot. After ingot making, the steel ingot subjected to soaking treatment and the steel ingot not subjected to soaking were subjected to slab rolling, hot rolling and annealing.
【００４６】表７は表６に示した鋼での本発明法の適用
有無材による900 ℃で2.7 kgf/mm2におけるクリープ・
ラプチャー試験結果を示す。ソーキング処理を適用した
鋼のクリープ破断時間はソーキング未適用鋼に比べ、い
ずれも長時間側にあり、実験室試験鋼塊と同様に優れた
耐クリープ特性を示すことがわかる。Table 7 shows the creep strength of the steels shown in Table 6 at 900 ° C and 2.7 kgf / mm 2 with and without the application of the method of the present invention.
4 shows the results of a rupture test. The creep rupture time of the steel to which the soaking treatment was applied was longer than that of the steel to which the soaking treatment was not applied, indicating that the steel exhibited excellent creep resistance characteristics as well as the laboratory test ingot.
【００４７】[0047]
【表６】 [Table 6]
【００４８】[0048]
【表７】 [Table 7]
【００４９】(実施例３)表８に本発明鋼および比較鋼の
化学組成 (重量％、残部はFe) を示す。これらの試料は
高周波電気炉 (真空溶解) で溶製した25kg鋼塊を鍛造、
熱間圧延を施し、1130℃で溶体化処理を行った。これ
ら、供試材に対し高温特性のうち、耐酸化性と高温強度
特性を評価した。(Example 3) Table 8 shows the chemical compositions (wt%, balance Fe) of the steel of the present invention and the comparative steel. These samples were forged from a 25kg steel ingot melted in a high frequency electric furnace (vacuum melting).
Hot rolling was performed and solution treatment was performed at 1130 ° C. Among these test materials, the oxidation resistance and the high-temperature strength characteristics among the high-temperature characteristics were evaluated.
【００５０】[耐酸化性]表９に表１に示した本発明鋼と
一部の比較鋼についての酸化試験結果を示す。試験は大
気中、1000℃で200 時間の連続加熱および1000℃×25分
加熱−５分空冷繰り返し試験を最高400 サイクル (200
時間相当) まで行った。[Oxidation resistance] Table 9 shows the results of the oxidation test for the steel of the present invention shown in Table 1 and some comparative steels. The test was repeated in air at 1000 ° C for 200 hours and repeated at 1000 ° C for 25 minutes and air-cooled for 5 minutes.
Hours).
【００５１】ここで、連続酸化試験では、剥離酸化スケ
ールを含む全重量変化で、繰り返し酸化試験では試験前
後の試験片重量変化で評価した。本発明鋼の200 時間連
続加熱後の酸化増量 (剥離スケール含む) はいずれも50
g/m2以下であり優れた耐酸化性を示している。比較鋼に
おいては高SiのNo.24 鋼および高Crで高NiのNo.27 鋼は
比較的良好な耐酸化性を示すもののその他の鋼はいずれ
も劣っている。Here, in the continuous oxidation test, evaluation was made based on the total weight change including the peeled oxidation scale, and in the repeated oxidation test, evaluation was made based on the weight change of the test piece before and after the test. The oxidation increase (including exfoliation scale) of the steel of the present invention after continuous heating for 200 hours was 50
g / m 2 or less, indicating excellent oxidation resistance. In the comparative steels, the high Si No. 24 steel and the high Cr and high Ni No. 27 steel show relatively good oxidation resistance, but all other steels are inferior.
【００５２】一方、加熱−空冷繰り返し試験では本発明
鋼ではいずれも400 サイクル後の酸化重量変化は±50g/
m2の範囲であり、比較鋼のうち低Cr鋼や連続加熱で優れ
た耐酸化性を示した高Si鋼はいずれも酸化重量が大きく
減少しておりスケール剥離が著しいことが分かる。On the other hand, in the heating-air cooling repetition test, in the case of the steels of the present invention, the change in oxidation weight after 400 cycles was ± 50 g /
In the range of m 2 , it can be seen that, among the comparative steels, the low chromium steel and the high Si steel which exhibited excellent oxidation resistance by continuous heating all have a greatly reduced oxidation weight and marked scale peeling.
【００５３】[高温強度特性]表８に示した本発明鋼と一
部の比較鋼について1000℃で1.0 kgf/mm2 におけるクリ
ープ・ラプチャー試験結果を表10に示す。本発明鋼はい
ずれもクリープ破断時間がかなり長時間側にあり、優れ
た耐クリープ特性を示すことがわかる。[High-Temperature Strength Properties] Table 10 shows the results of creep rupture tests at 1.0 ° C and 1.0 kgf / mm 2 at 1000 ° C for the steels of the present invention shown in Table 8 and some comparative steels. It can be seen that all the steels of the present invention have a considerably long creep rupture time and exhibit excellent creep resistance.
【００５４】図２は供試材のクリープ破断強度を横軸Al
量、縦軸Ｎ量で整理した図である。この図より、N(%)＋
2Al(%)≦0.500(%)であればクリープ特性が良好であるこ
とがわかる。図中には1130℃溶体化時に残存する未固溶
AlN 量 (残渣Al量および窒化物中Ｎ量) も示したが、Al
N の残存によりクリープ特性が低下することが分かる。
このように、適正なAl、Ｎ成分範囲とすることで高温強
度、延性、靱性の向上が達成される。FIG. 2 shows the creep rupture strength of the test material on the horizontal axis Al.
It is the figure arranged by quantity and the vertical axis N quantity. From this figure, N (%) +
If 2Al (%) ≦ 0.500 (%), the creep characteristics are good. In the figure, the undissolved solution remaining at 1130 ° C solution
The AlN content (residual Al content and N content in nitride) is also shown.
It can be seen that the creep characteristics deteriorate due to the remaining N.
Thus, by setting the Al and N component ranges in an appropriate range, improvement in high-temperature strength, ductility, and toughness is achieved.
【００５５】上述のように本発明鋼は従来の高温用部材
として使用されている高Cr−高Ni鋼および高Siオーステ
ナイトステンレス鋼の組織安定性を大幅に改善し、か
つ、高温での耐酸化性に優れた特性を有するオーステナ
イト系ステンレス鋼である。さらに、本発明鋼は高価な
Niの使用を極力抑えており経済性にも優れているため高
温用部材として広範囲の使用が期待される。As described above, the steel of the present invention significantly improves the microstructure stability of high Cr-high Ni steel and high Si austenitic stainless steel used as conventional high temperature members, and is resistant to oxidation at high temperatures. Austenitic stainless steel with excellent properties. Furthermore, the steel of the present invention is expensive
Since the use of Ni is suppressed as much as possible and it is economical, it is expected to be used in a wide range as a high temperature member.
【００５６】[0056]
【表８】 [Table 8]
【００５７】[0057]
【表９】 [Table 9]
【００５８】[0058]
【表１０】 [Table 10]
【００５９】[0059]
【発明の効果】上述のように、本発明によれば、従来の
高温用部材として使用されている高Cr−高Ni鋼および高
Siオーステナイトステンレス鋼の欠点である溶接性を大
幅に改善でき、かつ、高温での耐酸化性、耐摩耗性およ
び高温強度のいずれにおいても優れた特性を有するオー
ステナイト系ステンレス鋼が得られる。さらに、本発明
にかかる鋼は、高価なNiの使用を極力抑えており経済性
にも優れているため高温用部材として広範囲の分野での
使用が期待される。As described above, according to the present invention, a high Cr-high Ni steel and a high
An austenitic stainless steel can be obtained which can significantly improve the weldability, which is a disadvantage of Si austenitic stainless steel, and has excellent properties in all of oxidation resistance at high temperatures, wear resistance and high-temperature strength. Furthermore, since the steel according to the present invention minimizes the use of expensive Ni and is excellent in economy, it is expected to be used in a wide range of fields as a high-temperature member.
【図１】実施例のクリープラプチャー試験結果およびト
ランスバレストレイン試験での最大割れ長さと、Niバラ
ンス値との関係を示したグラフである。FIG. 1 is a graph showing the relationship between the results of a creep rupture test and the maximum crack length in a Transvarestrain test of an example and the Ni balance value.
【図２】図２は、1000℃×1.0 kgf/mm2 クリープ破断試
験結果を横軸Al量、縦軸Ｎ量で整理した結果を示すグラ
フである。FIG. 2 is a graph showing results of creep rupture test results at 1000 ° C. × 1.0 kgf / mm 2 , arranged in terms of Al content on the horizontal axis and N content on the vertical axis.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大塚 伸夫 大阪市中央区北浜４丁目５番33号 住友 金属工業株式会社内 (72)発明者 小川 和博 大阪市中央区北浜４丁目５番33号 住友 金属工業株式会社内 (72)発明者 安楽 敏朗 大阪市中央区北浜４丁目５番33号 住友 金属工業株式会社内 (56)参考文献 特開 昭59−1658（ＪＰ，Ａ) 特開 昭60−92454（ＪＰ，Ａ) 特開 昭56−102550（ＪＰ，Ａ) 特開 平２−247330（ＪＰ，Ａ) 特開 昭59−80757（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) C21D 6/00 102 C21D 8/00 C22C 38/00 - 38/60 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuo Otsuka 4-5-33 Kitahama, Chuo-ku, Osaka City Inside Sumitomo Metal Industries, Ltd. (72) Inventor Kazuhiro Ogawa 4-5-33 Kitahama, Chuo-ku, Osaka Sumitomo Inside Metal Industry Co., Ltd. (72) Inventor Toshiro Anraku 4-5-33 Kitahama, Chuo-ku, Osaka City Inside Sumitomo Metal Industries Co., Ltd. (56) References JP-A-59-1658 (JP, A) JP-A-60- 92454 (JP, A) JP-A-56-102550 (JP, A) JP-A-2-247330 (JP, A) JP-A-59-80757 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) C21D 6/00 102 C21D 8/00 C22C 38/00-38/60
Claims (3)
下、 Ｐ:0.04 ％以下、 Ｓ:0.01 ％以下、 Cr: 20〜30
％、 Ni:10 〜15％、 Ｎ:0.10 〜0.30％、 Ｂ:0.0010
〜0.01％、 La＋Ce: 0.01〜0.10％、Al: 0.01〜0.20％、 残部実質的にFeおよび不可避的不純物 より成り、下記式で示されるNiバランス値が−1.0 ％〜
＋3.0 ％の範囲にある鋼組成を有することを特徴とする
溶接性に優れた高温用オーステナイト系ステンレス鋼。 Niバランス値 (重量%)＝%Ni+0.5×%Mn+30×(%C+%N)−1.
1×(%Cr+1.5×%Si)＋8.2C. 0.05 to 0.15%, Si: less than 1.0%, Mn: 2.0% or less, P: 0.04% or less, S: 0.01% or less, Cr: 20 to 30% by weight.
%, Ni: 10 to 15%, N: 0.10 to 0.30%, B: 0.0010
~ 0.01%, La + Ce: 0.01 ~ 0.10%, Al: 0.01 ~ 0.20%, the balance substantially consists of Fe and unavoidable impurities, and the Ni balance value represented by the following formula is -1.0% ~
Austenitic stainless steel for high temperature with excellent weldability characterized by having a steel composition in the range of + 3.0%. Ni balance value (% by weight) =% Ni + 0.5 x% Mn + 30 x (% C +% N)-1.
1 × (% Cr + 1.5 ×% Si) +8.2
下、 Ｐ:0.04 ％以下、 Ｓ:0.01 ％以下、 Cr: 20〜30
％、 Ni:10 〜15％、 Ｎ:0.10 〜0.30％、 Ｂ:0.0010
〜0.01％、 La＋Ce: 0.01〜0.10％、Al: 0.01〜0.20％を含み、かつ
ＮとAlが次式を満足する量で含有し、 Ｎ(%) ＋２Al(%) ≦0.500% 残部実質的にFeおよび不可避的不純物 より成る鋼組成を有することを特徴とする溶接性に優れ
た高温用オーステナイト系ステンレス鋼。2. C: 0.05 to 0.15%, Si: less than 1.0%, Mn: 2.0% or less, P: 0.04% or less, S: 0.01% or less, Cr: 20 to 30% by weight.
%, Ni: 10 to 15%, N: 0.10 to 0.30%, B: 0.0010
~ 0.01%, La + Ce: 0.01 ~ 0.10%, Al: 0.01 ~ 0.20%, and N and Al are contained in an amount satisfying the following formula: N (%) + 2Al (%) ≤0.500% High-temperature austenitic stainless steel with excellent weldability, characterized by having a steel composition consisting of Fe and unavoidable impurities.
する鋼に対し、分塊圧延前に1150〜1350℃の温度範囲で
２時間以上ソーキング処理を行った後、分塊圧延、熱間
圧延、および焼鈍処理を行うことを特徴とする溶接性に
優れた高温用オーステナイト系ステンレス鋼の製造方
法。3. A steel having the steel composition according to claim 1 or 2 is subjected to a soaking treatment in a temperature range of 1150 to 1350 ° C. for 2 hours or more before bulk rolling, followed by bulk rolling and hot working. A method for producing a high-temperature austenitic stainless steel excellent in weldability, characterized by performing rolling and annealing.
Priority Applications (2)
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|---|---|---|---|
| JP6260613A JP2970432B2 (en) | 1993-11-11 | 1994-10-25 | High temperature stainless steel and its manufacturing method |
| US08/686,397 US5824264A (en) | 1994-10-25 | 1996-07-25 | High-temperature stainless steel and method for its production |
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|---|---|---|---|
| JP5-282727 | 1993-11-11 | ||
| JP28272793 | 1993-11-11 | ||
| JP6260613A JP2970432B2 (en) | 1993-11-11 | 1994-10-25 | High temperature stainless steel and its manufacturing method |
| US08/686,397 US5824264A (en) | 1994-10-25 | 1996-07-25 | High-temperature stainless steel and method for its production |
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| Publication Number | Publication Date |
|---|---|
| JPH07188869A JPH07188869A (en) | 1995-07-25 |
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|---|---|---|---|---|
| EP2980244A4 (en) * | 2013-03-28 | 2016-09-28 | Nippon Steel & Sumikin Sst | Heat-resistant austenitic stainless steel sheet |
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|---|---|---|---|---|
| JP5208354B2 (en) | 2005-04-11 | 2013-06-12 | 新日鐵住金株式会社 | Austenitic stainless steel |
| JP4577256B2 (en) * | 2006-04-05 | 2010-11-10 | 住友金属工業株式会社 | Austenitic stainless steel |
| JP5464037B2 (en) * | 2010-05-10 | 2014-04-09 | 新日鐵住金株式会社 | Austenitic stainless steel, stainless steel products, and methods for producing them |
| KR102015510B1 (en) * | 2017-12-06 | 2019-08-28 | 주식회사 포스코 | Non-magnetic austenitic stainless steel with excellent corrosion resistance and manufacturing method thereof |
-
1994
- 1994-10-25 JP JP6260613A patent/JP2970432B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2980244A4 (en) * | 2013-03-28 | 2016-09-28 | Nippon Steel & Sumikin Sst | Heat-resistant austenitic stainless steel sheet |
| KR101744432B1 (en) | 2013-03-28 | 2017-06-08 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Heat-resistant austenitic stainless steel sheet |
| US9945016B2 (en) | 2013-03-28 | 2018-04-17 | Nippon Steel & Sumikin Stainless Steel Corporation | Heat-resistant austenitic stainless steel sheet |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07188869A (en) | 1995-07-25 |
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