JPH05156411A - High-si austenitic stainless cast steel for concentrated nitric acid having excellent castability and toughness - Google Patents
High-si austenitic stainless cast steel for concentrated nitric acid having excellent castability and toughnessInfo
- Publication number
- JPH05156411A JPH05156411A JP32208091A JP32208091A JPH05156411A JP H05156411 A JPH05156411 A JP H05156411A JP 32208091 A JP32208091 A JP 32208091A JP 32208091 A JP32208091 A JP 32208091A JP H05156411 A JPH05156411 A JP H05156411A
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- Prior art keywords
- nitric acid
- toughness
- concentrated nitric
- austenitic stainless
- castability
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、鋳造性および靱性に優
れた濃硝酸用高Siオーステナイト系ステンレス鋳鋼に関
する。TECHNICAL FIELD The present invention relates to a high Si austenitic stainless cast steel for concentrated nitric acid which is excellent in castability and toughness.
【０００２】[0002]
【従来の技術】硝酸製造プラントの主要構成部は、高温
・高濃度硝酸環境におかれる。かかる環境は、酸化性が
極めて強く、一般のステンレス鋼を用いたのでは、過不
働態状態となるために不働態皮膜を維持できない。しか
も、それは粒界腐食性が著しく苛酷な腐食環境でもあ
り、従来のステンレス鋼では硝酸製造プラント用の材料
としての使用に耐えない。2. Description of the Related Art The main components of a nitric acid production plant are placed in a high temperature, high concentration nitric acid environment. Such an environment is extremely strong in oxidizing property, and if a general stainless steel is used, the passive film cannot be maintained because it is in a passive state. Moreover, it is also a severe corrosive environment with extremely high intergranular corrosion, and conventional stainless steel cannot withstand use as a material for a nitric acid production plant.
【０００３】このような酸化性の強い高温・高濃度硝酸
環境においては、シリケート皮膜が耐用性を有するた
め、従来はグラスライニング材が使用されていた。しか
し、かかる材料は溶接不可能であるために大型の装置の
製作が困難であり、また脆くて衝撃に弱い等プラントの
保守上、重大な問題があった。In such a high-temperature, high-concentration nitric acid environment having a strong oxidizing property, a glass lining material has been conventionally used because the silicate film has durability. However, since such a material cannot be welded, it is difficult to manufacture a large-scale device, and it is fragile and vulnerable to impact, which is a serious problem in plant maintenance.
【０００４】近年では、この種の環境で耐用性を有する
金属材料として、約４％（以下、本明細書においては特
にことわりがない限り「％」は「重量％」を意味するも
のとする）とSi含有量を高めた17％Cr−14％Ni−４％Si
オーステナイト系ステンレス鋳鋼が使用されており、こ
れは酸化性の強い環境下において表面にSiO2主体の酸化
物層を形成するため、硝酸製造プラント装置の信頼性を
飛躍的に向上させている。In recent years, as a metal material having durability in this type of environment, about 4% (hereinafter, "%" means "% by weight" unless otherwise specified). And Si content increased 17% Cr-14% Ni-4% Si
Austenitic cast stainless steel is used, which forms a SiO 2 -based oxide layer on the surface in an environment with strong oxidizing properties, and thus dramatically improves the reliability of nitric acid production plant equipment.
【０００５】この17％Cr−14％Ni−４％Siオーステナイ
ト系ステンレス鋳鋼としては、例えば特公昭57−37669
号公報に、Ｃ：0.10％以下、Si：2.5 〜５％、Mn：２％
以下、Cr: 15〜20％、Ni：10〜22％、TaおよびZrの中の
少なくとも１元素：Ｃ×10以上で、かつ最大2.5 ％以下
（これらの成分は部分的にNbで補うことができる) 、残
部が実質的にFeよりなる共沸組成以上の濃度の硝酸に耐
えかつ優れた溶接性を特徴とする濃硝酸用ステンレス鋼
が開示されている。この種の耐硝酸性ステンレス鋼は、
その優れた特性から今日まで多くの使用実績があり、当
業界にあって評価の高い材料となっている。As this 17% Cr-14% Ni-4% Si austenitic stainless cast steel, for example, Japanese Patent Publication No. 57-37669.
In the publication, C: 0.10% or less, Si: 2.5-5%, Mn: 2%
Below, Cr: 15 to 20%, Ni: 10 to 22%, at least one element in Ta and Zr: C × 10 or more, and a maximum of 2.5% or less (these components may be partially supplemented by Nb. However, a stainless steel for concentrated nitric acid is disclosed which is resistant to nitric acid having a concentration equal to or higher than the azeotropic composition with the balance being substantially Fe and has excellent weldability. This type of nitric acid resistant stainless steel
Due to its excellent properties, it has been used extensively to date and is a material highly evaluated in the industry.
【０００６】前述したように、濃硝酸は厳しい粒界腐食
を示す環境であるため、シリケート皮膜による耐食性の
向上とともに、溶接熱影響部でのCr炭化物の析出に伴う
粒界鋭敏化の抑制が重要であり、この対策として、前述
の17％Cr−14％Ni−４％Siオーステナイト系ステンレス
鋼では、上述のようにNb等の安定化元素を添加してい
る。As described above, since concentrated nitric acid is an environment showing severe intergranular corrosion, it is important to improve the corrosion resistance by the silicate film and to suppress the intergranular sensitization associated with the precipitation of Cr carbide in the weld heat affected zone. As a countermeasure against this, in the above-mentioned 17% Cr-14% Ni-4% Si austenitic stainless steel, a stabilizing element such as Nb is added as described above.
【０００７】[0007]
【発明が解決しようとする課題】しかし、特公昭57−37
669 号公報に開示されているような高Si−高Nbオーステ
ナイト系ステンレス鋳鋼は、鋳造性が悪く鋼片の製造が
容易ではない。また、例えば特開昭63−140795号公報に
も開示されているように、Ni−Si−Nb系金属間化合物の
生成による耐濃硝酸性および靱性の劣化を招く等の問題
もある。ここに、本発明の目的は、鋳造性、耐濃硝酸性
および靱性に優れた濃硝酸用高Siオーステナイト系ステ
ンレス鋳鋼を提供することにある。[Problems to be Solved by the Invention] However, JP-B-57-37
The high Si-high Nb austenitic stainless cast steel disclosed in Japanese Patent No. 669 has poor castability and is not easy to manufacture a billet. Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 63-140795, there is a problem that the concentration of nitric acid and the toughness are deteriorated due to the formation of Ni—Si—Nb intermetallic compounds. An object of the present invention is to provide a high Si austenitic stainless cast steel for concentrated nitric acid which is excellent in castability, concentrated nitric acid resistance and toughness.
【０００８】[0008]
【課題を解決するための手段】本発明者らは、鋳造性、
耐濃硝酸性および靱性に優れた濃硝酸用高Siオーステナ
イト系ステンレス鋳鋼を得るために種々調査および研究
を行った結果、材料組成を適宜コントロールすることに
より、上記課題を解決することができることを知見し
て、本発明を完成した。The present inventors have found that the castability,
As a result of various investigations and studies to obtain a high Si austenitic stainless cast steel for concentrated nitric acid with excellent concentrated nitric acid resistance and toughness, it was found that the above problems can be solved by appropriately controlling the material composition. Then, the present invention was completed.
【０００９】ここに、本発明の要旨とするところは、重
量％で、Ｃ≦0.03％、Si:3.5〜６％、Mn≦３％、Cr:15
〜20％、Ni:10 〜20％、Nb≦0.3 ％、Ｎ≦0.05％、残部
Feおよび不可避的不純物 から成る鋼組成を有し、かつ下式で表されるNibal.が−
６〜−１であることを特徴とする鋳造性及び靱性に優れ
た濃硝酸用高Siオーステナイト系ステンレス鋳鋼であ
る。 Ni−bal.＝%Ni+30(%C+%N)+0.5%Mn-1.1(%Cr+1.5%Si+0.5%Nb)+8.2 なお、上記の本発明において、含有される前記Nbの少な
くとも一部はTaで置換されてもよい。Here, the gist of the present invention is, by weight%, C ≦ 0.03%, Si: 3.5 to 6%, Mn ≦ 3%, Cr: 15.
〜20%, Ni: 10〜20%, Nb ≦ 0.3%, N ≦ 0.05%, balance
It has a steel composition consisting of Fe and inevitable impurities, and Nibal.
It is a high Si austenitic stainless cast steel for concentrated nitric acid, which is excellent in castability and toughness, characterized by being 6 to -1. Ni-bal. =% Ni + 30 (% C +% N) + 0.5% Mn-1.1 (% Cr + 1.5% Si + 0.5% Nb) +8.2 In the present invention described above, at least the Nb contained. Some may be replaced by Ta.
【００１０】[0010]
【作用】以下、本発明を作用効果とともに詳述する。ま
ず、本発明において組成およびNi−bal.の範囲を限定す
る理由を以下に詳述する。The operation of the present invention will be described in detail below. First, the reason for limiting the composition and the range of Ni-bal. In the present invention will be described in detail below.
【００１１】Ｃ：耐食性、特に耐粒界腐食性を改善する
ためには、特に粒界腐食性の大きい高温・濃硝酸環境下
においてCr炭化物の生成を防止することが望ましく、か
かる観点からＣ含有量はできるだけ低い方が好ましい。
しかし、Ｃ含有量を極端に低下することはコストアップ
につながるため、上限を0.03％とする。そこで、本発明
ではＣ含有量は、0.03％以下と限定する。好ましくは、
0.01％以上0.02％以下である。C: In order to improve the corrosion resistance, particularly the intergranular corrosion resistance, it is desirable to prevent the formation of Cr carbide in a high temperature / concentrated nitric acid environment where the intergranular corrosion resistance is particularly high. The amount is preferably as low as possible.
However, if the C content is extremely reduced, the cost will increase, so the upper limit is made 0.03%. Therefore, in the present invention, the C content is limited to 0.03% or less. Preferably,
It is 0.01% or more and 0.02% or less.
【００１２】Si：Siは、フェライト組織を安定化させ、
鋳造性を向上させるとともに、高酸化性環境下において
鋼表面にSiO2系皮膜を生成させて耐濃硝酸を付与する主
要元素であり、かかる耐濃硝酸性を確保するためには3.
5 ％以上の添加が必要である。しかし、６％を超えて添
加すると靱性を阻害する。そこで、本発明では、Si含有
量は 3.5％以上６％以下と限定する。Si: Si stabilizes the ferrite structure,
In addition to improving castability, it is a major element that gives concentrated nitric acid resistance by forming a SiO 2 -based film on the steel surface in a highly oxidizing environment.To secure such concentrated nitric acid resistance, 3.
It is necessary to add more than 5%. However, if added over 6%, the toughness is impaired. Therefore, in the present invention, the Si content is limited to 3.5% or more and 6% or less.
【００１３】Mn：Mnは、オーステナイト生成元素として
オーステナイト組織を安定化させるとともに、工業生産
上は脱酸剤、脱硫剤としても有用な元素である。しか
し、３％を越えて添加すると、耐濃硝酸性を劣化させ
る。そこで、本発明では、Mn含有量は３％以下と限定す
る。好ましくは、１％以上３％以下である。Mn: Mn is an element that stabilizes the austenite structure as an austenite forming element and is also useful as a deoxidizing agent and a desulfurizing agent in industrial production. However, if added over 3%, the resistance to concentrated nitric acid deteriorates. Therefore, in the present invention, the Mn content is limited to 3% or less. Preferably, it is 1% or more and 3% or less.
【００１４】Cr：Crは、一般の耐食性および低・中濃度
の硝酸に対する耐食性を確保するため、15％以上添加す
る必要がある。しかし、Crの添加量が20％を越えると、
本発明においては、Siとの共存によりオーステナイトマ
トリクス中に多量のフェライトが析出した二相組織を呈
し、加工性を害するとともに靱性の低下を招く。そこ
で、本発明では、Cr含有量は15％以上20％以下と限定す
る。Cr: Cr must be added in an amount of 15% or more in order to secure general corrosion resistance and corrosion resistance to nitric acid of low and medium concentrations. However, if the added amount of Cr exceeds 20%,
In the present invention, the coexistence with Si exhibits a two-phase structure in which a large amount of ferrite is precipitated in the austenite matrix, which impairs the workability and lowers the toughness. Therefore, in the present invention, the Cr content is limited to 15% or more and 20% or less.
【００１５】Ni:Niは、主要なオーステナイト生成元素
であり、本発明においても、Cr、Si、Nb等のフェライト
生成元素とバランスして組織をオーステナイトに保ち、
良好な鋳造性および靱性を確保する。かかる効果を得る
ために、Ni含有量は10％以上20％以下と限定する。Ni: Ni is a main austenite-forming element, and in the present invention, the structure is maintained in austenite in balance with ferrite-forming elements such as Cr, Si and Nb.
Ensure good castability and toughness. In order to obtain this effect, the Ni content is limited to 10% or more and 20% or less.
【００１６】Nb：Nbは、鋼中ＣおよびＮをNb炭窒化物と
して固定し、特に溶接熱影響部での粒界腐食の防止に有
効な安定化元素である。しかし、0.3 ％を越えて添加す
ると金属間化合物の生成が顕著となり、鋳造性、耐濃硝
酸性および靱性を劣化させる。そこで、本発明ではNb含
有量は0.3 ％以下と限定する。好ましくは、0.01％以上
0.3 ％以下である。Nb: Nb is a stabilizing element that fixes C and N in steel as Nb carbonitrides and is particularly effective in preventing intergranular corrosion in the weld heat affected zone. However, if added in excess of 0.3%, the formation of intermetallic compounds becomes remarkable, and the castability, concentrated nitric acid resistance and toughness deteriorate. Therefore, in the present invention, the Nb content is limited to 0.3% or less. Preferably 0.01% or more
It is less than 0.3%.
【００１７】Ｎ：Ｎは、Ｃと同様に耐粒界腐食性を阻害
するため、できるだけ低い方が好ましいが、鋳造性を勘
案して上限を0.05％とする。そこで、本発明では、Ｎ含
有量は0.05％以下と限定する。N: N, like C, inhibits intergranular corrosion resistance, so it is preferably as low as possible, but the upper limit is made 0.05% in consideration of castability. Therefore, in the present invention, the N content is limited to 0.05% or less.
【００１８】Ni−bal.：下記式によりNi−bal.を、 Ni−bal.＝%Ni+30(%C+%N)+0.5%Mn-1.1(%Cr+1.5%Si+0.5%Nb)+8.2 と定義し、本発明では、このNi−bal.が−６以上−１以
下と限定する。Ni−bal.が−６未満であると靱性が大幅
に劣化し、また−１超であると鋳造性が劣化するからで
ある。Ni-bal .: Ni-bal. =% Ni + 30 (% C +% N) + 0.5% Mn-1.1 (% Cr + 1.5% Si + 0.5% Nb) by the following formula. It is defined as +8.2, and in the present invention, this Ni-bal. Is limited to -6 or more and -1 or less. This is because if the Ni-bal. Is less than -6, the toughness deteriorates significantly, and if it exceeds -1, the castability deteriorates.
【００１９】かかる組成およびNi−bal.を有する本発明
にかかる高Siオーステナイト系ステンレス鋳鋼は、鋳造
性及び靱性に優れるとともに、共沸組成以上の濃度の硝
酸に耐えることができる濃硝酸用高Siオーステナイト系
ステンレス鋳鋼である。The high Si austenitic stainless cast steel according to the present invention having such a composition and Ni-bal. Is excellent in castability and toughness and has a high Si content for concentrated nitric acid capable of withstanding nitric acid having a concentration higher than the azeotropic composition. Austenitic stainless cast steel.
【００２０】なお、本発明にかかる鋳造性及び靱性に優
れる濃硝酸用高Siオーステナイト系ステンレス鋳鋼にお
ける安定化元素であるNbと同等の作用を示す元素として
Taがある。したがって、本発明では、Nbの少なくとも一
部をTaで置換して用いてもよい。さらに、本発明を実施
例とともに詳述するが、これは本発明の例示であり、こ
れにより本発明が限定されるものでない。It should be noted that as an element exhibiting an action equivalent to that of Nb which is a stabilizing element in the high Si austenitic stainless cast steel for concentrated nitric acid according to the present invention, which has excellent castability and toughness.
There is Ta. Therefore, in the present invention, at least part of Nb may be replaced with Ta and used. Further, the present invention will be described in detail with reference to Examples, but this is an illustration of the present invention and the present invention is not limited thereto.
【００２１】[0021]
【実施例】表１には、本発明例および比較例の化学成分
および各々のNi−bal.の値を示す。EXAMPLES Table 1 shows the chemical components of the examples of the present invention and comparative examples and the values of each Ni-bal.
【００２２】[0022]
【表１】 [Table 1]
【００２３】これらの鋼は、大気中で高周波溶解炉を用
いて溶解し、砂型に鋳込んだ後、鋳肌状況の評価を行
い、さらに溶体化熱処理および溶接を施し、溶接部の割
れの感受性評価を行った。また、これらの材料から溶接
部を含むように試料を採取し表面切削後湿式600 番研摩
を施し腐食試験に供した。さらに、母材の一部から２mm
のＶノッチを設けた５×10×55mmの試験片を切り出し、
０℃で衝撃試験を行った。結果を表２にまとめて示す。These steels were melted by using a high frequency melting furnace in the atmosphere, cast into a sand mold, and then the condition of the casting surface was evaluated. Further, solution heat treatment and welding were performed, and crack susceptibility of the welded portion was evaluated. An evaluation was made. In addition, samples were taken from these materials so as to include the welded part, and after surface cutting, wet 600 polishing was applied and used for the corrosion test. 2mm from a part of the base material
Cut out a 5 × 10 × 55 mm test piece with the V notch of
An impact test was performed at 0 ° C. The results are summarized in Table 2.
【００２４】[0024]
【表２】 [Table 2]
【００２５】表２には、表１に示した各鋼の表面性状評
価および溶接割れ感受性評価に基づく鋳造性評価結果、
シャルピー衝撃試験結果および硝酸製造プラント中 (98
％HNO3、沸騰状態およびNOx ガス雰囲気) での2328hr経
過後の腐食試験結果をそれぞれ示す。Table 2 shows the castability evaluation results based on the surface property evaluation and weld crack susceptibility evaluation of each steel shown in Table 1,
Charpy impact test results and nitric acid production plant (98
The results of the corrosion test after 2328 hours have been shown in% HNO 3 , boiling state and NOx gas atmosphere).
【００２６】表２に示すように、本発明の範囲を満足す
る試料 (試料No.1、2 、4 、9 、11および13) は、鋳造
性に優れ、かつ衝撃試験結果および腐食試験結果とも良
好であることが分かる。これに対して、試料No.3、14お
よび15は、いずれもNb含有量が0.3 ％を越えているた
め、鋳造性が劣化していることがわかる。As shown in Table 2, the samples satisfying the scope of the present invention (Sample Nos. 1, 2, 4, 9, 11 and 13) were excellent in castability and had both impact test results and corrosion test results. It turns out that it is good. On the other hand, Sample Nos. 3, 14 and 15 all have a Nb content of more than 0.3%, and thus it is clear that the castability is deteriorated.
【００２７】試料No.5は、Si含有量が本発明の範囲の上
限を超えているため、靱性の劣化が著しい。試料No.6
は、Ni−bal.が−１よりも大きいため、鋳造性が劣化し
ていることがわかる。試料No.7は、Si含有量が本発明の
範囲の下限を下回っているために耐食性の劣化が著し
い。In sample No. 5, the Si content exceeds the upper limit of the range of the present invention, so the toughness is significantly deteriorated. Sample No.6
It can be seen that since the Ni-bal. Is larger than -1, the castability is deteriorated. In Sample No. 7, the Si content is below the lower limit of the range of the present invention, and therefore the corrosion resistance is significantly deteriorated.
【００２８】試料No.8は、Mn含有量が本発明の範囲の上
限を上回っているために耐食性が劣化している。試料N
o.10 は、Ni−bal.が本発明の範囲の下限を下回ってい
るために靱性の劣化が著しい。Sample No. 8 has a deteriorated corrosion resistance because the Mn content exceeds the upper limit of the range of the present invention. Sample N
In o.10, since Ni-bal. is below the lower limit of the range of the present invention, the toughness is significantly deteriorated.
【００２９】さらに、試料No.12 は、Ni−bal.が本発明
の範囲の上限を上回っているために鋳造性が劣化してい
る。このように、本発明では、Nb含有量が0.3 ％を超え
るか、またはNi−bal.が−１を超えると、鋳造性が劣化
することがわかる。Further, in Sample No. 12, the castability is deteriorated because Ni-bal. Exceeds the upper limit of the range of the present invention. As described above, in the present invention, it is understood that the castability is deteriorated when the Nb content exceeds 0.3% or the Ni-bal. Exceeds -1.
【００３０】次に、図１には、表２中の衝撃試験におけ
る吸収エネルギーとNi-bal. との関係を、図２には、吸
収エネルギーと (Nb＋Ta) 量との関係をそれぞれグラフ
で示す。図１から、Ni-bal. が−６未満においては、急
激な靱性劣化 (吸収エネルギーの低下) がみられる。Next, FIG. 1 is a graph showing the relationship between the absorbed energy and Ni-bal. In the impact test in Table 2, and FIG. 2 is a graph showing the relationship between the absorbed energy and the amount of (Nb + Ta). .. From Fig. 1, when Ni-bal. Is less than -6, a rapid deterioration in toughness (decrease in absorbed energy) is observed.
【００３１】また、図２から、0.3 ％を越える (Nb＋T
a) の添加の場合にも著しい靱性劣化が認められる。図
３には、表２中の濃硝酸による腐食試験における腐食度
とSi量との関係を、図４には、腐食度とNb＋Ta量との関
係をそれぞれグラフで示す。Further, from FIG. 2, the value of 0.3% is exceeded (Nb + T
Significant deterioration of toughness is also observed when a) is added. FIG. 3 shows the relationship between the degree of corrosion and the amount of Si in the corrosion test with concentrated nitric acid in Table 2, and FIG. 4 is a graph showing the relationship between the degree of corrosion and the amount of Nb + Ta.
【００３２】図３から、3.5 ％以上のSiの添加により良
好な耐濃硝酸性が得られることがわかる。なお、同図中
に示すように３％を越えるMnの添加 (試料No.8) は、耐
濃硝酸性を低下させることもわかる。また、図４に示す
ように0.3 ％を越えるNb＋Taの添加は靱性のみならず耐
濃硝酸性にも悪影響を及ぼすことがわかる。It can be seen from FIG. 3 that good concentrated nitric acid resistance can be obtained by adding 3.5% or more of Si. As shown in the figure, addition of Mn in excess of 3% (Sample No. 8) reduces the concentrated nitric acid resistance. Further, as shown in FIG. 4, it is understood that addition of Nb + Ta exceeding 0.3% adversely affects not only toughness but also concentrated nitric acid resistance.
【００３３】[0033]
【発明の効果】以上詳述したように、本発明により、鋳
造性、耐濃硝酸性および靱性に優れた濃硝酸用高Siオー
ステナイト系ステンレス鋳鋼を提供することが可能とな
った。かかる効果を有する本発明の意義は著しい。As described in detail above, according to the present invention, it becomes possible to provide a high Si austenitic stainless cast steel for concentrated nitric acid, which is excellent in castability, concentrated nitric acid resistance and toughness. The significance of the present invention having such effects is remarkable.
【図１】表２中の衝撃試験における吸収エネルギーとNi
-bal. との関係を示すグラフである。FIG. 1 Absorbed energy and Ni in impact test in Table 2
It is a graph showing the relationship with -bal.
【図２】表２中の吸収エネルギーと (Nb＋Ta) 量との関
係を示すグラフである。FIG. 2 is a graph showing the relationship between the absorbed energy and the amount of (Nb + Ta) in Table 2.
【図３】表２中の濃硝酸による腐食試験における腐食度
とSi量との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the degree of corrosion and the amount of Si in the corrosion test with concentrated nitric acid in Table 2.
【図４】表２中の腐食度とNb＋Ta量との関係を示すグラ
フである。FIG. 4 is a graph showing the relationship between the degree of corrosion and the amount of Nb + Ta in Table 2.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 青木 正紘 東京都新宿区本塩町８番地の２ 日本ステ ンレス株式会社内 (72)発明者 三木 正義 愛媛県新居浜市惣開町５番１号 住友化学 工業株式会社内 (72)発明者 久本 寛 愛媛県新居浜市惣開町５番１号 住友化学 工業株式会社内 (72)発明者 坂田 勝廣 愛媛県新居浜市惣開町５番１号 住友化学 工業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiro Aoki 8-8 Honshiocho, Shinjuku-ku, Tokyo Within Japan Stainless Co., Ltd. (72) Inventor Masayoshi Miki 5-1 Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Industrial Co., Ltd. (72) Inventor Hiroshi Hisamoto 5-1, Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Co., Ltd. (72) Inventor Katsuhiro Sakata 5-1-1, Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Co., Ltd.
Claims (2)
Ni:10 〜20％、 Nb≦0.3 ％、Ｎ≦0.05％、残部Feおよび不可避的不純物 から成る鋼組成を有し、かつ下式で表されるNi−bal.が
−６〜−１であることを特徴とする鋳造性及び靱性に優
れた濃硝酸用高Siオーステナイト系ステンレス鋳鋼。 Ni−bal.＝%Ni+30(%C+%N)+0.5%Mn-1.1(%Cr+1.5%Si+0.5%Nb)+8.21. By weight%, C ≦ 0.03%, Si: 3.5-6%, Mn ≦ 3%, Cr: 15-20%,
Ni: 10 to 20%, Nb ≤ 0.3%, N ≤ 0.05%, the balance of Fe and inevitable impurities in the steel composition, and the Ni-bal. Represented by the following formula is -6 to -1. A high Si austenitic stainless cast steel for concentrated nitric acid, which is characterized by excellent castability and toughness. Ni−bal. =% Ni + 30 (% C +% N) + 0.5% Mn-1.1 (% Cr + 1.5% Si + 0.5% Nb) +8.2
で置換されたことを特徴とする請求項１記載の鋳造性及
び靱性に優れた濃硝酸用高Siオーステナイト系ステンレ
ス鋳鋼。2. At least a part of the contained Nb is Ta.
The high Si austenitic stainless cast steel for concentrated nitric acid according to claim 1, which is excellent in castability and toughness.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32208091A JPH05156411A (en) | 1991-12-05 | 1991-12-05 | High-si austenitic stainless cast steel for concentrated nitric acid having excellent castability and toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32208091A JPH05156411A (en) | 1991-12-05 | 1991-12-05 | High-si austenitic stainless cast steel for concentrated nitric acid having excellent castability and toughness |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05156411A true JPH05156411A (en) | 1993-06-22 |
Family
ID=18139694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32208091A Withdrawn JPH05156411A (en) | 1991-12-05 | 1991-12-05 | High-si austenitic stainless cast steel for concentrated nitric acid having excellent castability and toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05156411A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05287460A (en) * | 1992-04-10 | 1993-11-02 | Nkk Corp | Austenitic stainless steel excellent in nitric acid corrosion resistance |
| CN103826766A (en) * | 2011-07-29 | 2014-05-28 | 新日铁住金株式会社 | Method for producing austenitic stainless steel |
-
1991
- 1991-12-05 JP JP32208091A patent/JPH05156411A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05287460A (en) * | 1992-04-10 | 1993-11-02 | Nkk Corp | Austenitic stainless steel excellent in nitric acid corrosion resistance |
| CN103826766A (en) * | 2011-07-29 | 2014-05-28 | 新日铁住金株式会社 | Method for producing austenitic stainless steel |
| EP2737961A4 (en) * | 2011-07-29 | 2015-06-03 | Nippon Steel & Sumitomo Metal Corp | Method for producing austenitic stainless steel |
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