JPS59222562A - Austenitic stainless steel with superior corrosion resistance - Google Patents
Austenitic stainless steel with superior corrosion resistanceInfo
- Publication number
- JPS59222562A JPS59222562A JP9578983A JP9578983A JPS59222562A JP S59222562 A JPS59222562 A JP S59222562A JP 9578983 A JP9578983 A JP 9578983A JP 9578983 A JP9578983 A JP 9578983A JP S59222562 A JPS59222562 A JP S59222562A
- Authority
- JP
- Japan
- Prior art keywords
- corrosion resistance
- stainless steel
- content
- austenitic stainless
- corrosion
- 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.)
- Pending
Links
- 230000007797 corrosion Effects 0.000 title claims description 42
- 238000005260 corrosion Methods 0.000 title claims description 42
- 229910000963 austenitic stainless steel Inorganic materials 0.000 title description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229910001566 austenite Inorganic materials 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 description 13
- 229910017604 nitric acid Inorganic materials 0.000 description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- -1 Cr6+ ions Chemical class 0.000 description 5
- 206010070834 Sensitisation Diseases 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- 230000008313 sensitization Effects 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000012958 reprocessing Methods 0.000 description 4
- 239000002915 spent fuel radioactive waste Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000003758 nuclear fuel Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Landscapes
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
本発明は、耐食性にすくれたオーステナイトステンレス
鋼、特に核燃料再処理装置の構造材料としてずくれた耐
食性を示ずオーステナイトステンレス鋼に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an austenitic stainless steel with poor corrosion resistance, and particularly to an austenitic stainless steel without poor corrosion resistance as a structural material for nuclear fuel reprocessing equipment.
従来、軽水炉の使用済み核燃料の再処理の際にみられる
ような高温の硝酸環境下で使用される材料としてば、２
５％Ｃｒ−２０％Ｎｉ系の材料（例：ＵＲ＾ＮＵＳ ６
５．、、商品名）が用いられている。しかし、硝酸中に
Ｃｒ６＋イオンが存在すると、それらのイオンが酸化剤
として材料に作用して粒界腐食を著しく加速することが
知られているように、上述のような環境においては慣用
の２５％Ｃｒ −２０％Ｎｉ系の材料でもまだ耐食性が
十分ではない場合がある。Conventionally, materials used in high-temperature nitric acid environments such as those found during the reprocessing of spent nuclear fuel in light water reactors include 2.
5%Cr-20%Ni material (e.g. UR^NUS 6
5. ,, product name) are used. However, as it is known that the presence of Cr6+ ions in nitric acid acts on the material as an oxidizing agent and significantly accelerates intergranular corrosion. Even Cr-20%Ni based materials may still not have sufficient corrosion resistance.
軽水炉を利用した原子力発電がかなり普及した現在、多
量の使用済み核燃料を再処理する必要が生じており、し
たがって、長期間の連続使用に耐えるずくれた耐食性を
備えた材料の開発が望まれている。Nowadays, nuclear power generation using light water reactors has become widespread, and there is a need to reprocess large amounts of spent nuclear fuel.Therefore, there is a desire to develop materials with excellent corrosion resistance that can withstand long-term continuous use. There is.
かかる要望を満たす材料としては以下のような特性を備
えていることが必要である。A material that satisfies these demands must have the following properties.
すなわぢ、軽水炉使用済み核燃料を再処理する際に見ら
れるような高温硝酸中で使用される材料では、硝酸に対
する耐食性が満足されなければならないのはもちろんの
こと、Ｃｒ６＋イオンや核燃料から混入した酸化剤（Ｒ
ｕ等）による腐食電位の上昇に伴う腐食速度の増加、粒
界腐食の加速現象に対してもより優れた耐食性を具備し
ていなければならない。In other words, materials used in high-temperature nitric acid, such as those found in the reprocessing of spent nuclear fuel from light water reactors, must not only have corrosion resistance to nitric acid, but also corrosion resistance from Cr6+ ions and nuclear fuel. Oxidizing agent (R
It must also have superior corrosion resistance against an increase in corrosion rate due to an increase in corrosion potential due to corrosion caused by u, etc., and an acceleration phenomenon of intergranular corrosion.
しかも、装置あるいは部材の組立てに溶接施行が行われ
ることを考慮した場合、溶接部の鋭敏化による耐食性劣
化を極力押えることも必要である。Furthermore, considering that welding is performed in the assembly of devices or members, it is also necessary to suppress deterioration of corrosion resistance due to sensitization of welded parts as much as possible.
かくして、本発明の目的とするところは、すぐれた溶接
性とともに、Ｃｒ６＋イオンの存在下でもすくれた耐食
性を示す、特に使用済み核燃料の再処理設備用構造材と
して有用なオーステナイトステンレス鋼を提供すること
である。Thus, an object of the present invention is to provide an austenitic stainless steel that exhibits excellent weldability and low corrosion resistance even in the presence of Cr6+ ions, and is particularly useful as a structural material for spent nuclear fuel reprocessing equipment. That's true.
ここに、本発明者らは、前述の従来材である２５％Ｃｒ
−２０％Ｎｉ系合金にむしろＮを積極的に添加すること
により、Ｃｒ６＋イオンの存在下でもすくれた耐食性を
示すことを見い出し、さらにＣｒ、Ｎｉ量を制限し、Ｃ
を低減し、またＮｂを適量添加することにより鋭敏化の
際におけるＣの安定化を図ったオーステナイトステンレ
ス鋼が上述のような目的を達成できることを見い出して
本発明を完成したものである。Here, the present inventors used 25% Cr, the above-mentioned conventional material.
It was discovered that by actively adding N to a -20%Ni alloy, it exhibits excellent corrosion resistance even in the presence of Cr6+ ions, and by further limiting the amounts of Cr and Ni, C
The present invention was completed by discovering that an austenitic stainless steel with reduced C and stabilization of C during sensitization by adding an appropriate amount of Nb can achieve the above-mentioned objectives.
よって、本発明は
重量％で、
’ Ｃ：ｏ、ｏ２％以下、 Ｓｉ：’０．４％以下
、Ｍｎ ： Ｏ’、１〜１２％、 Ｃｒ：・１５〜３
０％、Ｎｉミニフル２８、 Ｐ ：’ｏ、ｏ２％以
下、Ｎ：０．０８〜０．３０％、
Ｎｂ ： Ｎｂ （％）≧１０Ｃ（％）、ただし０．４
％以下、残部実質的にＦｅよりなる、耐食性に優れたオ
ー・Ｐ
ステナイトステンレス鋼である。Therefore, the present invention has the following properties in terms of weight percent: C: o, 2% or less, Si: 0.4% or less, Mn: O', 1 to 12%, Cr: ・15 to 3
0%, Ni mini full 28, P: 'o, o2% or less, N: 0.08-0.30%, Nb: Nb (%) ≧ 10C (%), but 0.4
% or less, the balance is substantially composed of Fe, and is an O-P stenite stainless steel with excellent corrosion resistance.
本発明において合金組成を上述のように制限したＣ：Ｃ
は鋭敏化を促進するので耐粒界腐食性を向上させるため
にはＣ含有量はできるだけ低減することが望ましい。本
発明にあっては、Ｃ： ０．０２％を越えると粒界腐食
性が悪くなるので、本発明においてＣ含有量は０．０２
％以下とする。In the present invention, C:C with the alloy composition limited as described above
Since C promotes sensitization, it is desirable to reduce the C content as much as possible in order to improve intergranular corrosion resistance. In the present invention, C: If it exceeds 0.02%, intergranular corrosion will deteriorate, so in the present invention, the C content is 0.02%.
% or less.
Ｓｔ ： Ｓｉは脱酸剤として０．４％以下含有させる
。St: Si is contained as a deoxidizing agent in an amount of 0.4% or less.
Ｍｎ ： Ｍｎは脱酸剤およびオーステナイト安定化元
素として０．１〜１２％含有させる。なお、脱酸剤とし
ては２％までの添加で十分であるが、オーステナイト安
定化元素としては１２％まで添加して耐食性の一層の改
善をはかることができるが、それを越えると、加工性が
劣化する。Mn: Mn is contained in an amount of 0.1 to 12% as a deoxidizing agent and an austenite stabilizing element. It is sufficient to add up to 2% as a deoxidizing agent, and as an austenite stabilizing element, it is possible to further improve corrosion resistance by adding up to 12%. to degrade.
Ｃｒ ： Ｃｒは一般の耐食性ばかりでなく硝酸に対す
る耐食性を確保するために、１５％以上は必要である。Cr: 15% or more of Cr is required to ensure not only general corrosion resistance but also corrosion resistance against nitric acid.
また、Ｃｒ含有量の高い方が耐食性は良いが、しかし３
０％を越えるとその耐食性向上効果が飽和される。Also, the higher the Cr content, the better the corrosion resistance, but 3
If it exceeds 0%, the effect of improving corrosion resistance is saturated.
また、多量に加えるとオーステナイト組織を確保するた
めＮｉ含有量を高めることによる加工性の劣化およびコ
ストアップが生じるためＣｒ含有量の上限を３０％とす
る。Further, if added in a large amount, the Ni content is increased to ensure an austenitic structure, resulting in deterioration in workability and increase in cost, so the upper limit of the Cr content is set at 30%.
Ｎｉニオ−ステナイト組織にするために必要な量として
、Ｎｉ含有量は７〜２８％とする。The Ni content is set to 7 to 28% as the amount necessary to form a Ni niostenite structure.
Ｎｂ：Ｃを安定化させるためＣ含有量の１０倍以上含有
させる（Ｎｂ／Ｃ≧１０）。ただし、溶接性を考慮し、
０．４％以下とする。Nb: In order to stabilize C, it is contained at least 10 times the C content (Nb/C≧10). However, considering weldability,
It should be 0.4% or less.
Ｐ：耐粒界腐食性を改善するために低い方が望ましく、
したがって、本発明にあっては、Ｐ含有量は０．０２％
以下とする。P: Lower is desirable in order to improve intergranular corrosion resistance,
Therefore, in the present invention, the P content is 0.02%
The following shall apply.
Ｎ：従来材ではＮは０．０２％≧程度は不可避的に混入
してくる不純物であるが、本発明者らの知見によればＮ
： ０．０８％以上の添加で全面腐食、粒界腐食の両
方を著しく改善する。したがうて、本発明にあってはＮ
：０．０８％以上を添加する。しかし、Ｎ含有量が０．
３％を越えると製造が困難になるため、Ｎ添加の上限は
０．３％とする。N: In conventional materials, N is an impurity that is unavoidably mixed in at a level of 0.02% or more, but according to the findings of the present inventors, N
: Addition of 0.08% or more significantly improves both general corrosion and intergranular corrosion. Therefore, in the present invention, N
:Add 0.08% or more. However, the N content is 0.
If it exceeds 3%, manufacturing becomes difficult, so the upper limit of N addition is set at 0.3%.
次に、実施例によって本発明をさらに説明する。Next, the present invention will be further explained by examples.
尖血拠
第１表に合金組成を示す各供試材について、溶接１１ｈ
の熱影響部での鋭敏化を想定し、１１００℃×３０分加
熱×水冷、次いで６５０℃×３０時間加熱×空冷の熱処
理を行って鋭敏化を行った。かくして得られた供試材を
用いて、Ｃｒ”＋イオンの存在下での硝酸溶液中の耐食
性試験を行った。この耐食性試験は８Ｎ−ＨＮＯ３＋０
．３ ｇ／ｌ！ Ｃｒ６＋イオンのＣｒ Ｇ＋イオン
含有硝酸溶液を用い、その沸１．ｉｔ！溶液に上記各供
試材を４８時間浸漬して行った。For each sample material whose alloy composition is shown in Table 1, welding was carried out for 11 hours.
Assuming sensitization in the heat-affected zone, sensitization was performed by performing heat treatment at 1100° C. for 30 minutes and water cooling, then at 650° C. for 30 hours and air cooling. Using the thus obtained test material, a corrosion resistance test in a nitric acid solution in the presence of Cr"+ ions was conducted. This corrosion resistance test was carried out using 8N-HNO3+0
．． 3g/l! Using a nitric acid solution containing Cr6+ ions and CrG+ ions, boil it 1. It! The test was carried out by immersing each of the above test materials in the solution for 48 hours.
このときの耐食性試験の結果を腐食速度および粒界腐食
深さについてグラフにまとめて第１図ないし第３図に示
す。図中、各番号は第１表の合金番号を示す。The results of the corrosion resistance test at this time are summarized in graphs regarding corrosion rate and intergranular corrosion depth, and are shown in FIGS. 1 to 3. In the figure, each number indicates the alloy number in Table 1.
第１図のグラフは２５％Ｃｒ −２０％Ｎ ｉ −０，
０２％Ｐの各供試材について、Ｃ含有量の粒界腐食深さ
に及ぼす影響を示したものであり、図示結果からもＣ含
有量が０．０２％を越えると、耐食性が著しく劣化する
のが分かる。なお、本例は参考例として示すものであっ
て、各供試材はＮｂを含まず、Ｎ含有量も少ないもので
あるが、Ｎｂはすでに述べたようにＣの安定化作用があ
り、またＮ添加は後述するように耐食性向上に著しい効
果があることから、第１図に示す結果と比較することに
よって本発明によればさらに一層すぐれた効果が得られ
るのが分かる。The graph in Figure 1 is 25%Cr -20%N i -0,
This shows the effect of C content on intergranular corrosion depth for each sample material containing 0.02% P. From the results shown, when the C content exceeds 0.02%, the corrosion resistance deteriorates significantly. I understand. Note that this example is shown as a reference example, and each sample material does not contain Nb and has a small N content. However, as already mentioned, Nb has a stabilizing effect on C, and As will be described later, the addition of N has a remarkable effect on improving corrosion resistance, and a comparison with the results shown in FIG. 1 shows that the present invention provides even more excellent effects.
第２図に示すグラフは、０．０１％Ｇ−０，０１５％Ｐ
とした各供試材について腐食速度に及ぼすＮ含有量の影
響を示したものであり、Ｎ添加量の増加に伴い耐食性の
向上がみられるが、特にＮ含有量が０．０８％よりふえ
ると耐食性が著しく改善される。The graph shown in Figure 2 is 0.01%G-0,015%P
This figure shows the effect of N content on the corrosion rate for each sample material, and it can be seen that corrosion resistance improves as the amount of N added increases, but especially when the N content increases above 0.08%. Corrosion resistance is significantly improved.
次に、第３図は、０．０１％Ｃ−０，０１５％Ｐの各供
試料でのＮ含有量の粒界腐食深さに及ぼす影蓼を示した
ものであり、Ｎ含有量が高くなるにつれ耐食性の改善が
著しいが、特にＮ含有ｆｔｏ、０８％以上で顕著になる
。Next, Figure 3 shows the effect of N content on intergranular corrosion depth in each sample of 0.01%C-0.015%P. The improvement in corrosion resistance is remarkable as the steel increases, but it becomes especially noticeable when the N content fto is 08% or more.
第１図ないし第３図は本発明の実施例における耐食性試
験の結果をそれぞれまとめて示すグラフである。
出願人 住友金属工業株式会社
代理人 弁理士 広 瀬 章 −
＃７図
Ｃ（父ン
地２（２１
ぬ３ 図
Ｎ （＋／＋ンFIGS. 1 to 3 are graphs summarizing the results of corrosion resistance tests in Examples of the present invention. Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent Attorney Akira Hirose − #7 Diagram C
Claims (1)
ｎ二０．１〜１２％、 Ｃｒ：１５〜３０％、Ｎｉミ
ニフル２８、 ｐ：ｏ、ｏ２％以下、Ｎ ：０．
０８〜０．３０％、 Ｎｂ：Ｎｂ（％）≧１００（％）、ただし０．４％以下
、残部実質的にＦｅよりなる、耐食性に優れたオーステ
ナイ１へステンレス鋼。[Claims] Weight %: C: 0.02% or less, Si: 0.4% or less, M
n2 0.1-12%, Cr: 15-30%, Ni mini full 28, p: o, o 2% or less, N: 0.
08 to 0.30%, Nb: Nb (%) ≧ 100 (%), but not more than 0.4%, the remainder substantially consisting of Fe, stainless steel to Austenite 1 with excellent corrosion resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9578983A JPS59222562A (en) | 1983-06-01 | 1983-06-01 | Austenitic stainless steel with superior corrosion resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9578983A JPS59222562A (en) | 1983-06-01 | 1983-06-01 | Austenitic stainless steel with superior corrosion resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59222562A true JPS59222562A (en) | 1984-12-14 |
Family
ID=14147219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9578983A Pending JPS59222562A (en) | 1983-06-01 | 1983-06-01 | Austenitic stainless steel with superior corrosion resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59222562A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5116569A (en) * | 1989-08-11 | 1992-05-26 | Hitachi, Ltd. | Austenitic steel excellent in resistance to neutron irradiation embrittlement and members made of the steel |
-
1983
- 1983-06-01 JP JP9578983A patent/JPS59222562A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5116569A (en) * | 1989-08-11 | 1992-05-26 | Hitachi, Ltd. | Austenitic steel excellent in resistance to neutron irradiation embrittlement and members made of the steel |
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