JPH07116556B2 - Austenitic heat resistant steel for processing - Google Patents
Austenitic heat resistant steel for processingInfo
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- JPH07116556B2 JPH07116556B2 JP61209659A JP20965986A JPH07116556B2 JP H07116556 B2 JPH07116556 B2 JP H07116556B2 JP 61209659 A JP61209659 A JP 61209659A JP 20965986 A JP20965986 A JP 20965986A JP H07116556 B2 JPH07116556 B2 JP H07116556B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は，高温の腐食性雰囲気で，特に高温塩腐食また
は溶融塩腐食等，塩を含む腐食が問題となる雰囲気で繰
り返し加熱・冷却を受けるような用途に使用される加工
性に優れたオーステナイト系耐熱鋼に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is capable of performing repeated heating and cooling in a high temperature corrosive atmosphere, particularly in an atmosphere where corrosion containing a salt is a problem, such as high temperature salt corrosion or molten salt corrosion. The present invention relates to an austenitic heat-resisting steel having excellent workability, which is used for such applications.
自動車の排気ガス浄化システム，各種のボイラー，焼却
炉あるいは高炉羽口バーナーなどの厳しい腐食環境下で
使用される耐熱鋼に要求される特性としては高温強度特
性，耐高温酸化特性，酸化スケールの剥離抵抗などの一
般的耐熱性に加えて，燃焼雰囲気での高温ガス腐食ある
いはPbO,V2O5などの各種酸化物,PbCl2,NaCl,MgCl2,KCl
などの塩化物などを含む雰囲気での耐高温塩腐食およ
び，さらに高温での溶融塩腐食抵抗がある。さらに，例
えば，冷却時には凝縮水による湿食の問題もある。この
ような厳しい環境の下では耐熱性表面処理鋼板ではもた
ず，耐熱用ステンレス鋼が用いられ，このうち，耐熱性
以外に加工性および溶接性が要求される用途ではオース
テナイト系ステンレス鋼が選択される。Characteristics required for heat-resistant steel used in severe corrosive environments such as automobile exhaust gas purification systems, various boilers, incinerators or blast furnace tuyere burners are high temperature strength characteristics, high temperature oxidation resistance, and oxide scale delamination. In addition to general heat resistance such as resistance, high temperature gas corrosion in combustion atmosphere or various oxides such as PbO, V 2 O 5 , PbCl 2 , NaCl, MgCl 2 , KCl
It has high temperature salt corrosion resistance in an atmosphere containing chloride, etc., and molten salt corrosion resistance at higher temperatures. Furthermore, for example, there is a problem of wet corrosion due to condensed water during cooling. Under such a severe environment, heat resistant stainless steel is used instead of heat resistant surface treated steel. Of these, austenitic stainless steel is selected for applications requiring workability and weldability in addition to heat resistance. To be done.
SUS304で代表されるオーステナイト系耐熱鋼は大気中で
繰り返し加熱・冷却を受けるとフェライト系耐熱鋼に比
べスケールが剥離するという問題があり，これはオース
テナイト系耐熱鋼の熱膨張が大きく加熱・冷却を受ける
と素地とスケールとの熱膨張差によってスケールに亀裂
を生じ剥離するもので，これが大きな欠点となってい
た。これに対し，例えば特公昭56−25507号公報に開示
されているように，高Si含有のオーステナイト系ステン
レス鋼が種々開発され，従来のSUS304に比べスケールの
剥離抵抗の著しい改善がなされSUS310Sに匹敵するか，
それ以上の特性を示すようになった。しかしながら，最
近になってこれらの鋼でもなお腐食が生じる問題が発生
した。Austenitic heat-resisting steels such as SUS304 have the problem that the scale peels off compared to ferritic heat-resisting steels when they are repeatedly heated and cooled in the atmosphere. When it receives, it causes a crack in the scale due to the difference in thermal expansion between the base material and the scale, causing the scale to peel off, which was a major drawback. On the other hand, as disclosed in, for example, Japanese Patent Publication No. 56-25507, various austenitic stainless steels with a high Si content have been developed, and the peeling resistance of the scale has been significantly improved compared to the conventional SUS304, which is comparable to SUS310S. Or,
It came to show more characteristics. However, these steels have recently encountered the problem of corrosion.
すなわち，大量廃棄物処理等に用いる焼却炉，高炉の羽
口バーナー，重油ボイラー，内燃機関の排ガス管などで
使用されている部材の一部に著しい高温腐食を生じてい
る例がみつかり問題となっている。これらの腐食事例を
調査した結果，共通した現象として粒界腐食型の加速酸
化が発生しており高温で塩の付着した状態あるいは溶融
塩状態での腐食であり，特に塩化物を含む塩による高温
腐食が著しいことがわかった。この高温塩腐食に対して
は既存の耐熱用ステンレス鋼であるSUS304,SUS302B,SUS
XM15J1,SUS321,およびSUS310Sなどいずれも十分ではな
く新たな材料開発が望まれている。以下には溶融塩も含
めて単に高温塩腐食とよぶ。That is, there is a problem in that some parts used in incinerators used for large-scale waste disposal, tuyeres in blast furnaces, heavy oil boilers, exhaust gas pipes of internal combustion engines, etc. are remarkably hot corroded. ing. As a result of investigating these corrosion cases, a common phenomenon is intergranular corrosion type accelerated oxidation, which is corrosion in a state where salt is attached or in a molten salt state at a high temperature. It was found that the corrosion was significant. For this high temperature salt corrosion, existing heat resistant stainless steels SUS304, SUS302B, SUS
Neither XM15J1, SUS321, nor SUS310S is sufficient, and new material development is desired. Hereinafter, the molten salt will be simply referred to as high temperature salt corrosion.
本発明は耐熱性に優れ，特に耐高温塩腐食特性に優れ，
かつ粒界腐食感受性も合せて改善した加工用オーステナ
イト系耐熱鋼を提供することを目的とする。The present invention has excellent heat resistance, particularly excellent high temperature salt corrosion resistance,
It is also an object of the present invention to provide an austenitic heat-resistant steel for working, which has improved grain boundary corrosion susceptibility.
本発明者らは，前述の問題点を改善すべく研究を行った
結果，気基本組成がＣ≦0.06％,Si:5.0越え〜10％,Mn≦
2.0％,Ni:12〜20％,Cr:16越え〜23％,Ca:0.001〜0.05％
であることを特徴とし，さらに必要に応じて希土類元素
もしくはＹが添加され，かつ（Ｃ＋Ｎ）％に応じて適量
のTiあるいはNbを添加することで上記目的の材料が得ら
れることがわかった。すなわち，本発明の主題である耐
高温塩腐食特性の改善に対してはSi量を従来の範囲から
大きく高Si側に移行させ，さらにSiとの複合でCaを添加
すること，そして，さらに希土類元素もしくはＹを添加
することによって高温塩腐食環境下での保護皮膜を補強
し，かつ適量のNbおよび／あるいはTiの添加によって使
用時の鋭敏化を防止し，粒界浸食型の高温塩腐食と休止
時の湿食による粒界腐食をともに改善するものである。The present inventors have conducted research to improve the above-mentioned problems, and as a result, have a basic composition of C ≦ 0.06%, Si: more than 5.0 to 10%, Mn ≦
2.0%, Ni: 12 to 20%, Cr: over 16 to 23%, Ca: 0.001 to 0.05%
It was found that the above-mentioned target material can be obtained by further adding a rare earth element or Y, if necessary, and by adding an appropriate amount of Ti or Nb according to (C + N)%. That is, in order to improve the high temperature salt corrosion resistance, which is the subject of the present invention, the amount of Si is largely shifted from the conventional range to the high Si side, and Ca is added in combination with Si, and further rare earth is added. Addition of element or Y reinforces the protective film under high temperature salt corrosion environment, and addition of appropriate amount of Nb and / or Ti prevents sensitization at the time of use, resulting in intergranular erosion type high temperature salt corrosion. It is intended to improve both the intergranular corrosion due to the wet corrosion at rest.
すなわち，本発明によれば，重量％で， C:0.06％以下 Si:5％を越え10％以下， Mn:2.0％以下 Ni:12〜20％ Cr:16％を越え23％以下 Ca:0.001〜0.05％， を含有し，必要に応じ， NbとTiの１種または２種を0.1〜1.0％を含有し，かつNb
/（Ｃ＋Ｎ）≧8,Ti/（Ｃ＋Ｎ）≧４または（Ti＋0.5N
b）／（Ｃ＋Ｎ）≧４を満足し， さらに，希土類元素もしくはＹの１種または２種以上を
0.001〜0.1％を含有し， また，さらに,Bを0.0005〜0.010％,Cuを0.5〜2.5％を含
有してもよく， 残部がFeおよび製鋼上の不可避的不純物よりなる，各種
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有するオーステナイト系耐熱鋼を提供するものである。That is, according to the present invention, in wt%, C: 0.06% or less Si: 5% or more and 10% or less, Mn: 2.0% or less Ni: 12 to 20% Cr: 16% or more and 23% or less Ca: 0.001 〜0.05%, if necessary, one or two of Nb and Ti, 0.1 to 1.0%, and Nb
/ (C + N) ≧ 8, Ti / (C + N) ≧ 4 or (Ti + 0.5N
b) / (C + N) ≧ 4, and one or more of rare earth elements or Y
It may contain 0.001 to 0.1%, and may further contain 0.0005 to 0.010% of B and 0.5 to 2.5% of Cu, with the balance consisting of Fe and unavoidable impurities in steel making, which are suitable for various heat resistances. Provided is an austenitic heat-resistant steel having excellent resistance to high temperature salt corrosion.
以下には本発明を具体的に説明する。本発明の合金組成
ならびに各添加元素の添加目的ならびに組成範囲の限定
理由を述べる。The present invention will be specifically described below. The alloy composition of the present invention, the purpose of adding each additive element, and the reasons for limiting the composition range will be described.
C:強力なオーステナイト形成元素であり，高温強度を得
るためには必要な元素であるが,Cは高温でCr元素と結合
し，粒界にCr23C6として析出し，粒界近傍にCr欠乏層を
形成するので高温塩腐食の進行を助長するとともに，休
止時に凝縮水による粒界腐食が生じるので低い方が好ま
しく，上限を0.06％とした。C: A strong austenite-forming element, which is necessary for obtaining high-temperature strength, but C combines with Cr element at high temperature and precipitates as Cr 23 C 6 at grain boundaries, and Cr near the grain boundaries. Since a deficiency layer is formed, it promotes the progress of high temperature salt corrosion, and intergranular corrosion due to condensed water occurs at rest, so the lower limit is preferable, and the upper limit was made 0.06%.
Si:耐酸化性および耐高温塩腐食性を改善する上で最も
重要な元素で５％以下では耐高温塩腐食性に十分な効果
が得られず，一方10％以上では高温で多量のσ相を析出
し，靱性が劣化する。また，δフェライトが増し熱間加
工性が問題となり，さらに，硬さが増す為，加工性が低
下するので上限を10％とした。Si: The most important element for improving oxidation resistance and high temperature salt corrosion resistance. 5% or less does not provide sufficient effect on high temperature salt corrosion resistance, while 10% or more, a large amount of σ phase at high temperature Precipitates and the toughness deteriorates. In addition, δ-ferrite increases and hot workability becomes a problem. Further, hardness increases and workability decreases, so the upper limit was made 10%.
Mn:熱間加工性改善に有効であるが耐酸化性を低下させ
るので上限を2.0％とする。Mn: Effective for improving hot workability, but lowers oxidation resistance, so the upper limit is made 2.0%.
Ni:オーステナイト系ステンレス鋼の基本的合金元素で
あり，また合金元素として耐酸化性，耐高温塩腐食特性
の改善に有効である。本発明では耐高温湿塩腐食の点か
ら高Siを含有するため，熱間加工性を阻害するδフェラ
イトを生成しやすいので，成分バランスを考慮してNiの
下限を12％とした。一方，多量のNiは製品原価を上げる
ため好ましくないので上限を20％とした。Ni: It is a basic alloying element of austenitic stainless steel, and as an alloying element, it is effective for improving oxidation resistance and high temperature salt corrosion resistance. In the present invention, since high Si is contained from the viewpoint of high temperature wet salt corrosion resistance, it is easy to form δ ferrite which hinders hot workability. Therefore, the lower limit of Ni is set to 12% in consideration of the component balance. On the other hand, a large amount of Ni increases the product cost and is not preferable, so the upper limit was made 20%.
Cr:ステンレス鋼の耐食性および耐酸化性を維持するた
めに最も基本的な元素であり，本発明の対象とする用途
では16％以下では十分な効果が得られない。一方,23％
を越えて添加すると,Si含有量との関係からδフェライ
トを多量に生成するので上限を23％とした。Cr: This is the most basic element for maintaining the corrosion resistance and oxidation resistance of stainless steel, and in the intended use of the present invention, a sufficient effect cannot be obtained at 16% or less. On the other hand, 23%
If added in excess of 10%, a large amount of δ-ferrite is produced in relation to the Si content, so the upper limit was made 23%.
Ca:耐高温塩腐食に対する耐性は基本的にはCrとSiによ
って維持される。しかしながら，これは高温での連続使
用時では十分な保護性を有するものの，断続的な加熱・
冷却がある時にはスケール剥離などの為にしばしば腐食
の進行を生じ，このために断続加熱・冷却ではスケール
の剥離抵抗を高める必要がある。このような問題に対し
ては耐高温塩腐食を改善するために高Siとしたが，さら
にCa添加がより有効であることがわかった。すなわち,C
aは高温側での連続使用時の耐高温塩腐食の改善に効果
的であり，このためには,Caは少なくとも0.001％を要
し,0.05％は実際的に含有させられる上限である。Ca: Resistance to high temperature salt corrosion is basically maintained by Cr and Si. However, this has sufficient protection in continuous use at high temperatures, but intermittent heating and
When cooling is performed, corrosion often occurs due to scale peeling, and for this reason intermittent peeling of the scale must be increased by intermittent heating and cooling. For such problems, high Si was used to improve high temperature salt corrosion resistance, but it was found that addition of Ca is more effective. That is, C
a is effective in improving high temperature salt corrosion resistance during continuous use on the high temperature side, for which Ca requires at least 0.001%, and 0.05% is the practical upper limit.
Nb:粒界浸食型の高温塩腐食および休止時の凝縮水によ
る湿食を防止するためにＣを0.06％以下に抑えている
が，これでも不十分な場合にはNbを添加して粒界へのCr
の炭，窒化物の析出を防止する。このNbはC,Nと結合し
て微細なNb（C,N）を形成し，耐食性のみならず高温強
度，とりわけクリープ強度の改善に大きな効果を有す
る。Cr炭，窒化物の析出を防止するには重量比でNb/
（Ｃ＋Ｎ）≧８のNbが必要であるが，さらに高温強度を
向上させる目的からも0.1％以上のNb添加が必要であ
る。一方,1.0％以上のNb添加はδフェライト量を増加さ
せるので熱間加工性を害し，またδ相の析出を加速する
ので靱性が低下する。Nb: C is kept to 0.06% or less in order to prevent grain boundary erosion type high temperature salt corrosion and wet corrosion due to condensed water at rest, but if this is still insufficient, Nb is added to add grain boundary. Cr to
Prevents the precipitation of carbon and nitride. This Nb combines with C and N to form fine Nb (C, N), which has a great effect not only on corrosion resistance but also on improvement of high-temperature strength, especially creep strength. To prevent precipitation of Cr carbon and nitride, Nb /
Nb of (C + N) ≧ 8 is required, but addition of 0.1% or more of Nb is also required for the purpose of further improving high temperature strength. On the other hand, addition of 1.0% or more of Nb increases the amount of δ ferrite, impairs hot workability, and accelerates precipitation of the δ phase, resulting in lower toughness.
Ti:Nbと同一の目的からTiの添加も有効である。TiはC,N
と結合してTi（C,N）を形成して，耐食性のみならずク
リープ強度の改善に大きな効果を有する。Cr炭，窒化物
の析出を防止するには重量比でTi/（Ｃ＋Ｎ）≧４のTi
が必要であるが，さらに高温強度を向上させる目的から
も0.1％以上のTi添加が必要である。一方,1.0％以上のT
i添加はδフェライト量を増加させるので熱間加工性を
害し，またσ相の析出を加速するので靱性が劣化する。
Tiはまた加工性の改善にも効果がある。The addition of Ti is also effective for the same purpose as Ti: Nb. Ti is C, N
When combined with Ti to form Ti (C, N), it has a great effect on improving not only corrosion resistance but also creep strength. To prevent precipitation of Cr carbon and nitride, Ti / (C + N) ≧ 4 Ti by weight ratio
However, 0.1% or more of Ti must be added to improve the high temperature strength. On the other hand, T of 1.0% or more
Addition of i increases the amount of δ ferrite, which impairs hot workability, and accelerates the precipitation of σ phase, which deteriorates toughness.
Ti is also effective in improving workability.
なお,NbとTiはいずれか一方を含むだけでもよいが，複
合で添加する場合には（Ti＋0.5Nb）／（Ｃ＋Ｎ）≧４
を満足すればCr炭，窒化物の析出防止に有効である。It should be noted that Nb and Ti may only contain one or the other, but when they are added in combination, (Ti + 0.5Nb) / (C + N) ≧ 4
If the above condition is satisfied, it is effective in preventing the precipitation of Cr carbon and nitride.
希土類元素およびY:高温塩腐食環境下での加熱・冷却時
のスケール剥離抵抗の改善に有効であり，このために
は，希土類およびＹは少なくとも0.001％を要し,0.05％
を越えて含有しても，耐高温塩腐食が改善されることは
なくかつ高価な元素であるため,0.05％を上限とする。Rare earth elements and Y: Effective in improving scale peeling resistance during heating / cooling under high temperature salt corrosion environment. For this purpose, rare earth and Y require at least 0.001%, 0.05%
If it is contained in excess of 0.05%, the high temperature salt corrosion resistance is not improved and it is an expensive element, so the upper limit is 0.05%.
以上の組成に加えて，さらに，要求される特性に応じ
て，高温強度および熱間加工性の改善のためにＢを，ま
た，成形加工性および溶接性の改善からCuを添加する。
この場合,Bは少なくとも0.0005％を要するが，一方0.01
％を越えるとかえって熱間加工性を悪くするので上限は
0.01％とする。Cuは少なくとも0.5％を要するが，一方
2.5％を越えると結晶粒界に偏析して熱間加工性を著し
くそこねるので,2.5％を上限とする。In addition to the above composition, B is added to improve the high temperature strength and hot workability, and Cu is added to improve the formability and weldability according to the required characteristics.
In this case, B requires at least 0.0005%, while 0.01
%, The hot workability deteriorates, so the upper limit is
0.01%. Cu requires at least 0.5%, while
If it exceeds 2.5%, it segregates at the grain boundaries and the hot workability is significantly impaired, so 2.5% is made the upper limit.
つぎに，本発明鋼について実施例を挙げて説明する。第
１表に各種試験に用いた鋼の化学成分を示す。これらの
鋼は本発明鋼，本発明に規定する範囲外の比較鋼とJIS
規格鋼である。これらの鋼は真空溶解炉で溶製され，鍛
造によって直径25mm（25mmφ）の丸棒および厚さ40mm
（40mmt）の板とした。丸棒は1050゜〜1150℃の範囲で
溶体化熱処理後JISG0567およびZ2272に規定される高温
引張およびクリープ破断試験片に加工した。鍛造板は抽
出温度1200℃で熱延し,4mmtとし，以降，通常の冷延・
焼鈍によって1.5mmtの板を作製し，各種試験に供した。Next, the steel of the present invention will be described with reference to examples. Table 1 shows the chemical composition of steel used in various tests. These steels are steels of the present invention, comparative steels outside the range specified in the present invention and JIS
It is a standard steel. These steels are melted in a vacuum melting furnace and forged by a round bar with a diameter of 25 mm (25 mmφ) and a thickness of 40 mm.
(40mmt) plate. The round bar was subjected to solution heat treatment in the range of 1050 ° to 1150 ° C and processed into a high temperature tensile and creep rupture test piece specified in JIS G0567 and Z2272. The forged plate was hot-rolled at an extraction temperature of 1200 ° C to 4 mmt, and then the normal cold-rolling
A 1.5 mmt plate was prepared by annealing and used for various tests.
以下に，実験結果を詳細に説明する。The experimental results will be described in detail below.
第１図は,NaClの塗布試験による耐高温塩腐食特性に及
ぼすSiの影響を700℃×20時間の条件で示す。塗布試験
は学振法に準じて行った。即ち，アセトンにNaClを懸濁
し，これを試験片に20mg/cm2の割合で均一に塗布し，所
定の炉温に保持された電気炉中に装入した。 Figure 1 shows the effect of Si on the high temperature salt corrosion resistance of NaCl coating test under the condition of 700 ℃ × 20 hours. The coating test was conducted according to the Gakushin method. That is, NaCl was suspended in acetone, the test piece was evenly applied at a rate of 20 mg / cm 2 , and the test piece was placed in an electric furnace maintained at a predetermined furnace temperature.
この図から,Siを５％を越えて添加すると腐食減量は著
しく低減しており，耐高温塩腐食特性として十分な特性
を得るには５％を越えるSi添加が必要であることがわか
る。一般に，オーステナイト系ステンレス鋼の優れた耐
熱性はその表面に形成されるCr2O3の保護性皮膜による
が，この皮膜は大気酸化に対してはきわめて強固である
が，本発明の対象としている高温塩腐食環境下では保護
性が劣り，加速的に腐食が進行する。これに対し,Siを
５％より多く添加することで，高温塩腐食に強い保護性
の皮膜が形成されたものと考えられる。From this figure, it can be seen that the corrosion weight loss is remarkably reduced when Si is added in excess of 5%, and Si addition in excess of 5% is required to obtain sufficient characteristics as high temperature salt corrosion resistance. Generally, the excellent heat resistance of austenitic stainless steel depends on the protective film of Cr 2 O 3 formed on the surface of the austenitic stainless steel. This film is extremely strong against atmospheric oxidation, but is the object of the present invention. In a high temperature salt corrosive environment, the protection is poor and the corrosion progresses at an accelerated rate. On the other hand, it is considered that by adding more than 5% of Si, a protective film that is resistant to high temperature salt corrosion was formed.
第２図は前記と同様の塗布法（20時間）によって高温塩
腐食の温度依存性を調べ，高温塩腐食特性に及ぼすCaの
効果を示したものである。600〜700℃の範囲ではCaの効
果は認められないが,800℃になるとCaによる腐食減量の
低減効果が認められる。従ってCaをSiとの複合で添加す
ることによって耐高温塩腐食の進行を防止できる。FIG. 2 shows the effect of Ca on the hot salt corrosion characteristics by examining the temperature dependence of hot salt corrosion by the same coating method (20 hours) as described above. The effect of Ca is not recognized in the range of 600 to 700 ℃, but at 800 ℃, the effect of reducing the corrosion weight loss by Ca is recognized. Therefore, by adding Ca in combination with Si, the progress of high temperature salt corrosion resistance can be prevented.
第３図は飽和NaCl溶液を用いて繰り返し加熱−浸漬試験
を行ったもので,5分間浸漬,12分間650℃に加熱,65分間
空冷のサイクルを40回繰り返した場合の重合減少をみた
ものである。この図より，市販のJIS規格鋼種では高温
塩腐食の抵抗が本発明鋼に比べ著しく低いことがわか
る。また，本発明鋼の中でも特に希土類元素を含む鋼が
繰り返し高温塩腐食環境下での耐性が高いことがわか
る。Figure 3 shows the repeated heating-soaking test using saturated NaCl solution. It shows the decrease of polymerization when the cycle of soaking for 5 minutes, heating at 650 ° C for 12 minutes, and air cooling for 65 minutes was repeated 40 times. is there. From this figure, it is understood that the resistance to high temperature salt corrosion is significantly lower in the commercially available JIS standard steel type than in the steel of the present invention. Further, it can be seen that among the steels of the present invention, steel containing a rare earth element has a high resistance to repeated high temperature salt corrosion environments.
第２表に600〜800℃における高温短時間引張特性を示
す。同表から本発明鋼は優れた高温強度特性を有するこ
とがわかる。Table 2 shows the high-temperature short-time tensile properties at 600 to 800 ° C. It can be seen from the table that the steel of the present invention has excellent high temperature strength properties.
第３表に700℃，応力16,12,10kg/mm2の条件でクリープ
破断試験を行った結果を示す。同表から本発明鋼はクリ
ープ破断強度も高いことがわかる。本発明の鋼の中で,S
i単独添加の鋼は高温短時間引張強さは高いがクリープ
破断強度はそれ程高くはない。しかし，高SiでさらにN
b,Tiを添加した鋼は長時間強度が著しく改善されてい
る。なお,Bの添加は長時間側の強度改善に有効であり，
これはおもにクリープ延性の改善によるものと思われ
る。Table 3 shows the results of creep rupture tests under the conditions of 700 ° C and stress of 16,12,10 kg / mm 2 . From the table, it is understood that the steel of the present invention has high creep rupture strength. Among the steels of the present invention, S
The steel with i added alone has high tensile strength at high temperature for a short time, but creep rupture strength is not so high. However, high Si and N
The long-term strength of the steel containing b and Ti is remarkably improved. The addition of B is effective in improving the strength on the long-term side.
This is probably due to the improvement in creep ductility.
第４表に,650℃で２時間の鋭敏化熱処理後,JISG0575に
準じて硫酸・硫酸銅腐食試験を行い粒界腐食感受性を調
査した。この表より本発明鋼は比較鋼に比べ粒界腐食感
受性はきわめて低いことがわかる。In Table 4, after a sensitizing heat treatment at 650 ° C for 2 hours, a sulfuric acid / copper sulfate corrosion test was conducted according to JIS G0575 to investigate the intergranular corrosion susceptibility. From this table, it is understood that the steel of the present invention has extremely low intergranular corrosion susceptibility as compared with the comparative steel.
第５表に室温における機械的性質および硬さを示す。こ
の表よりTiあるいはNbの添加によって伸びの向上が認め
られ，特にTiは軟質化に有効であり，またCuの複合添加
によって軟質化と同時に伸びも向上する。Table 5 shows mechanical properties and hardness at room temperature. From this table, it is recognized that the addition of Ti or Nb improves the elongation. Particularly, Ti is effective for softening, and the combined addition of Cu improves the elongation simultaneously with the softening.
〔発明の効果〕 以上の実施例が示すように，従来，高温塩腐食あるいは
溶融塩腐食環境下では既存のオーステナイト系ステンレ
ス鋼では十分実用に耐えうる鋼がなく，そのために材料
温度の低減あるいは部材の早期交換によって対応せざる
を得なかったが，本発明鋼はステンレス系耐熱鋼として
十分な耐熱性を有しかつ，製造性および加工性にも優れ
ていることにより，本発明鋼は時代の要請に答えるもの
として技術的，社会的，経済的に大きな効果を示すもの
と思われる。 [Advantages of the Invention] As shown in the above examples, conventionally, in the hot salt corrosion or molten salt corrosion environment, no existing austenitic stainless steel can sufficiently withstand practical use. However, the steel of the present invention has sufficient heat resistance as a stainless steel heat-resistant steel and is excellent in manufacturability and workability. It seems that it will have great technical, social, and economic effects in responding to requests.
第１図は塗布法によるNaCl高温塩腐食特性を700℃×20
時間でみたもので，腐食減量に及ぼすSi添加の影響を示
す。 第２図は塗布法によるNaCl高温塩腐食特性を600℃〜800
℃×20時間でみたもので，腐食減量と試験温度の関係を
本発明鋼と比較鋼およびJIS規格鋼について示す。 第３図は飽和NaCl溶液（20℃）を用いて,5分間浸漬,120
分間650℃に加熱,5分間空冷のサイクルを40回繰り返し
た場合の重量減少を示す。Fig. 1 shows the characteristics of NaCl hot salt corrosion by the coating method at 700 ℃ × 20
It shows the effect of Si addition on the corrosion weight loss in terms of time. Figure 2 shows the corrosion characteristics of NaCl hot salt by the coating method from 600 ℃ to 800 ℃.
The relationship between the corrosion weight loss and the test temperature is shown for the present invention steel, the comparative steel, and the JIS standard steel. Figure 3 shows a saturated NaCl solution (20 ℃) for 5 minutes
The weight loss is shown when the cycle of heating to 650 ℃ for 5 minutes and air cooling for 5 minutes is repeated 40 times.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 清水 勇 山口県新南陽市大字富田4976番地 日新製 鋼株式会社周南研究所内 (56)参考文献 特開 昭50−43011（ＪＰ，Ａ) 特開 昭50−137325（ＪＰ，Ａ) 特開 昭50−137326（ＪＰ，Ａ) 特開 昭52−109421（ＪＰ，Ａ) 特開 昭52−138010（ＪＰ，Ａ) 特開 昭55−91960（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isamu Shimizu 4976 Tomita, Shinnanyo City, Yamaguchi Prefecture, Shunan Research Laboratories, Nisshin Steel Co., Ltd. (56) Reference JP-A-50-43011 (JP, A) JP 50-137325 (JP, A) JP-A 50-137326 (JP, A) JP-A 52-109421 (JP, A) JP-A 52-138010 (JP, A) JP-A 55-91960 (JP , A)
Claims (5)
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有する加工用オーステナイト系耐熱鋼。1. By weight%, C: 0.06% or less, Si: 5% to 10% or less, Mn: 2.0% or less, Ni: 12 to 20%, Cr: 16% to 23% or less, Ca: Austenitic heat-resistant steel for processing that contains 0.001 to 0.05%, the balance consisting of Fe and unavoidable impurities in steelmaking, and has excellent heat resistance and outstanding resistance to high temperature salt corrosion.
つ、Nb/（Ｃ＋Ｎ）≧８、Ti/（Ｃ＋Ｎ）≧４または（Ti
＋0.5Nb）／（Ｃ＋Ｎ）≧４を満足し、 残部がFeおよび製鋼上の不可避的不純物よりなり、各種
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有する加工用オーステナイト系耐熱鋼。2. By weight%, C: 0.06% or less, Si: 5% to 10% or less, Mn: 2.0% or less, Ni: 12 to 20%, Cr: 16% to 23% or less, Ca: 0.001 to 0.05%, 0.1 to 1.0% of one or two of Nb or Ti, and Nb / (C + N) ≧ 8, Ti / (C + N) ≧ 4 or (Ti
+ 0.5Nb) / (C + N) ≧ 4, the balance consisting of Fe and unavoidable impurities in steel making, excellent in various heat resistance and excellent resistance to high temperature salt corrosion. steel.
1〜0.05％、 を含有し、 残部がFeおよび製鋼上の不可避的不純物よりなり、各種
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有する加工用オーステナイト系耐熱鋼。3. By weight%, C: 0.06% or less, Si: 5% to 10% or less, Mn: 2.0% or less, Ni: 12 to 20%, Cr: 16% to 23% or less, Ca: 0.001 to 0.05%, one or more of rare earth elements and Y is 0.00 in total
Austenitic heat-resistant steel for processing, containing 1 to 0.05%, the balance consisting of Fe and unavoidable impurities in steel making, and having excellent heat resistance and outstanding resistance to high temperature salt corrosion.
1〜0.05％、 を含有し、 NbまたはTiの１種または２種を0.1〜1.0％含有し、か
つ、Nb/（Ｃ＋Ｎ）≧８、Ti/（Ｃ＋Ｎ）≧４または（Ti
＋0.5Nb）／（Ｃ＋Ｎ）≧４を満足し、 残部がFeおよび製鋼上の不可避的不純物よりなり、各種
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有する加工用オーステナイト系耐熱鋼。4. By weight%, C: 0.06% or less, Si: 5% to 10% or less, Mn: 2.0% or less, Ni: 12 to 20%, Cr: 16% to 23% or less, Ca: 0.001 to 0.05%, one or more of rare earth elements and Y is 0.00 in total
1 to 0.05%, 0.1 to 1.0% of one or two of Nb or Ti, and Nb / (C + N) ≧ 8, Ti / (C + N) ≧ 4 or (Ti
+ 0.5Nb) / (C + N) ≧ 4, the balance consisting of Fe and unavoidable impurities in steel making, excellent in various heat resistance and excellent resistance to high temperature salt corrosion. steel.
1〜0.05％、 NbまたはTiの１種または２種を0.1〜1.0％含有し、か
つ、Nb/（Ｃ＋Ｎ）≧８、Ti/（Ｃ＋Ｎ）≧４または（Ti
＋0.5Nb）／（Ｃ＋Ｎ）≧４を満足し、さらに B:0.0005〜0.010％、 Cu:0.5〜2.5％ を含有し、 残部がFeおよび製鋼上の不可避的不純物よりなり、各種
の耐熱性に優れかつ耐高温塩腐食に対して著しい抵抗を
有する加工用オーステナイト系耐熱鋼。5. In weight%, C: 0.06% or less, Si: 5% to 10% or less, Mn: 2.0% or less, Ni: 12 to 20%, Cr: 16% to 23% or less, Ca: 0.001 to 0.05%, one or more of rare earth elements and Y is 0.00 in total
1 to 0.05%, 0.1 to 1.0% of one or two of Nb or Ti, and Nb / (C + N) ≧ 8, Ti / (C + N) ≧ 4 or (Ti
+ 0.5Nb) / (C + N) ≧ 4, B: 0.0005-0.010% and Cu: 0.5-2.5% are contained, and the balance is Fe and unavoidable impurities in steelmaking. Austenitic heat resistant steel for processing that has excellent resistance to high temperature salt corrosion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61209659A JPH07116556B2 (en) | 1986-09-08 | 1986-09-08 | Austenitic heat resistant steel for processing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61209659A JPH07116556B2 (en) | 1986-09-08 | 1986-09-08 | Austenitic heat resistant steel for processing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6365058A JPS6365058A (en) | 1988-03-23 |
| JPH07116556B2 true JPH07116556B2 (en) | 1995-12-13 |
Family
ID=16576470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61209659A Expired - Lifetime JPH07116556B2 (en) | 1986-09-08 | 1986-09-08 | Austenitic heat resistant steel for processing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07116556B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03100134A (en) * | 1989-09-13 | 1991-04-25 | Nippon Yakin Kogyo Co Ltd | Fe-ni series alloy having excellent high temperature corrosion resistance and its manufacture |
| JP2759222B2 (en) * | 1989-09-20 | 1998-05-28 | 日新製鋼株式会社 | Austenitic stainless steel with excellent stress corrosion cracking resistance in chloride environment |
| CN103826766B (en) * | 2011-07-29 | 2015-11-25 | 新日铁住金株式会社 | The manufacture method of austenite stainless steel |
| CN105506501B (en) * | 2014-09-25 | 2018-12-28 | 宝钢不锈钢有限公司 | A kind of long-life heat-resistant high alloy steel and its manufacturing method |
| DE102019123174A1 (en) * | 2019-08-29 | 2021-03-04 | Mannesmann Stainless Tubes GmbH | Austenitic steel alloy with improved corrosion resistance when exposed to high temperatures |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2331100B2 (en) * | 1973-06-19 | 1978-05-03 | Vereinigte Edelstahlwerke Ag (Vew), Wien Niederlassung Vereinigte Edelstahlwerke Ag (Vew) Verkaufsniederlassung Buederich, 4005 Meerbusch | Heat-resistant, austenitic iron-chromium-nickel alloys |
| JPS50137326A (en) * | 1974-04-20 | 1975-10-31 | ||
| JPS5719185B2 (en) * | 1974-04-20 | 1982-04-21 | ||
| JPS52109421A (en) * | 1976-03-10 | 1977-09-13 | Nippon Steel Corp | Heat resisting steel with excellent hot and cold workability |
| JPS5827339B2 (en) * | 1976-05-14 | 1983-06-08 | 住友金属工業株式会社 | Heat-resistant steel with excellent hot workability and oxidation resistance |
| JPS5591960A (en) * | 1978-12-28 | 1980-07-11 | Sumitomo Chem Co Ltd | High silicon-nickel-chromium steel with resistance to concentrated |
-
1986
- 1986-09-08 JP JP61209659A patent/JPH07116556B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6365058A (en) | 1988-03-23 |
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