JPH0118143B2 - - Google Patents
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- Publication number
- JPH0118143B2 JPH0118143B2 JP6369280A JP6369280A JPH0118143B2 JP H0118143 B2 JPH0118143 B2 JP H0118143B2 JP 6369280 A JP6369280 A JP 6369280A JP 6369280 A JP6369280 A JP 6369280A JP H0118143 B2 JPH0118143 B2 JP H0118143B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- strength
- corrosion resistance
- hot workability
- amount
- 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.)
- Expired
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- 229910052710 silicon Inorganic materials 0.000 claims description 13
- 229910000963 austenitic stainless steel Inorganic materials 0.000 claims description 12
- 101150062705 Wipf3 gene Proteins 0.000 claims 2
- 239000012535 impurity Substances 0.000 claims 2
- 229910000831 Steel Inorganic materials 0.000 description 56
- 239000010959 steel Substances 0.000 description 56
- 230000007797 corrosion Effects 0.000 description 37
- 238000005260 corrosion Methods 0.000 description 37
- 229910052757 nitrogen Inorganic materials 0.000 description 14
- 238000005336 cracking Methods 0.000 description 10
- 230000001771 impaired effect Effects 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 229910052758 niobium Inorganic materials 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910001193 A-6 tool steel Inorganic materials 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 239000013535 sea water Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 229910000926 A-3 tool steel Inorganic materials 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910001087 A-4 tool steel Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Description
本発明は化学、海水、原子力等各種プラントや
食品、機械、船舶機械等に用いられる耐食性、加
工性に優れた高強度オーステナイト系ステンレス
鋼に関するものである。
オーステナイト系ステンレス鋼は耐食性、耐熱
性、加工性、機械的性質が優れているため広く使
用されている。最近機械、構造物の大型化が進
み、構造用ステンレス鋼の強度向上が強く求めら
れるようになつてきた。この要求に対して強度を
向上させたオーステナイト系ステンレス鋼として
は、SUS304にＮを0.15％程度添加した
SUS304N1、さらにこのSUS304N1にNb0.1％程
度添加したSUS304N2、さらに22Cr―13Ni―
5Mn―0.3N鋼、20Cr―6Ni―9Mn―0.3M鋼が知
られている。
これらの鋼の固溶化熱処理後の強度は前２者の
SUS304N1、SUS304N2の耐力が35Kg/mm2程度、
引張強さが75Kg/mm2程度と必ずしも十分な強度を
有していなく、後２者の鋼については耐力が45
Kg／mm2程度、引張強さが80Kg/mm2以上とほぼ満足で
きる強度を有している。しかしながら後２者の鋼
はＮを0.3％と多量に含有しているため、応力腐
食割れ感受性がSUS304に比べ大きく高強度構造
用オーステナイト系ステンレス鋼としては大きな
欠点となつている。さらにMn含有量が多いため
熱間加工性が劣るという欠点がある。
また、直接に高強度を狙つたものではないが、
高い強度を有する鋼としては25Cr―13Ni―0.3N
―1Mo鋼、17Cr―8Ni―8Mn―4Si―0.15N鋼が
知られている。しかしこれらは、耐力が40Kg/mm2
程度、引張り強さが78Kg/mm2程度と今一歩要求強
度に達しないものである。さらに前者の鋼は高
Cr鋼であり、後者の鋼は高Si鋼であるため共に
熱間加工性が劣るという欠点を有している。
本発明はかかる従来鋼の欠点を克服したもので
本発明者等が種々研究を重ねた結果、オーステナ
イト系ステンレス鋼の強度を上げるためＮ量を単
に増加させると、応力腐食割れ感受性が増大する
という欠点が生ずる。そこで、Ｎに加えてさらに
Si量を増加し、Si、Ｎの組合せにより80Kg/mm2の
引張り強さが得られる鋼の熱間加工性を調べた。
その結果は第１図に示したようにSi含有量の増加
につれて捻回値は上昇し、Si1.2％でほぼ満足し
得る値を示し、Si1.5％でほぼ一定となつており、
ＮにSiを組合せて用いた場合に加工性を向上する
ことがわかつた。さらに前記と同一組成の鋼につ
いて耐応力腐食割れ性について調べた。その結果
は第２図に示したように、これについてはSi量が
増加しＮ量が低くなるにしたがつて向上すること
がわかつた。
上述の結果に基づいて、Ｎに加えてSi量を増加
し、SiおよびＮの固溶化作用を活用する新しいタ
イプの高強度オーステナイト系ステンレス鋼を開
発したもので、Ｎの固溶強化力のみを利用した従
来の高強度鋼に比べ、同一強度でありながら加工
性が向上し、しかも応力腐食割れ感受性の増大を
抑制することが可能であることを見い出したもの
である。
しかし、Si量を増加した場合Ｎの固溶限界を低
下させ、鋼塊凝固時に気泡が発生する危険性が高
まる。そこで本発明者等はさらに研究を重ねた結
果、適量のMnを含有させるとともに、さらに凝
固時の偏析デルタフエライト量が２％以下となる
ようにCr、Ni量を調整することにより解決し得
ることを見い出したものである。
さらに、上記組成の鋼に0.2％のNbを含有させ
た場合の強度、熱間加工性について調べた結果、
第３図に示したように引張り強さはSUS304に比
べ大巾に向上し、捻回値についても若干向上する
ことがわかり、適量のNb含有は本発明鋼の組成
範囲で、結晶粒を微細化し強度を高めると同時に
熱間加工性を改善することを見つけたものであ
る。本発明鋼はこれらの諸知見をもとにして開発
したＮ、Siの固溶強化作用と、Nbの結晶粒微細
化による強化作用とを組合わせて利用した高強度
オーステナイト系ステンレス鋼である。
そして、本発明においては第２発明鋼として
Mo、Cu、Ｖを少量含有させることにより耐食性
をさらに向上させたものである。
以上のように本発明鋼は耐食性、加工性に優れ
た高強度オーステナイト系ステンレス鋼で、海
水、化学、原子力等の過酷な使用環境で使用され
る各種大型プラントの強度部材などに適したもの
である。
以下に本発明鋼について詳述する。
第１発明鋼は、重量比にしてC0.04〜0.07％、
Si1.2〜3.0％、Mn2.3〜5.5％、Ni8.4〜15％、
Cr16〜22％、N0.23〜0.40％、Nb0.05〜1.0％を含
有したもので、第２発明鋼は第１発明鋼にMo0.2
〜3.0％、Cu0.2〜3.0％、V0.05〜0.50％のうち１
種ないし２種以上を含有させ第１発明鋼の耐食性
をさらに向上させたものである。
以下に本発明鋼の成分限定理由について説明す
る。
ＣはＮと同様に素地を強化する重要な元素であ
り、炭化物による素地強化には0.04％未満では少
ない。反面Ｃは耐食性を著しく損う元素でもある
が、本発明鋼はNbを0.05〜1.0％含有させたもの
であり、Ｃを0.04％以上含有させても耐食性の低
下は殆んど表われない。しかしながら、0.07％を
越えて含有させると耐食性、熱間加工性を損うの
で上限を0.07％とした。
Ｎは本発明鋼においては最も重要な強化元素で
あり、かつ耐孔食性を著しく向上させる強力なオ
ーステナイト形成元素であり、これらの性能を発
揮させるには0.23％以上含有させる必要があり下
限を0.23％とした、反面Ｎは応力腐食割れ感受性
を増大させる元素でもあり、さらに0.40％を越え
て含有させると熱間加工性を著しく損うので上限
を0.40％とした。
Siは地質に固溶してそれを強化させる主要な元
素の一つであり、Si1％の含有はN0.08％含有に
相当する強化能力を有する。さらにSiは耐食性、
耐応力腐食割れ感受性をも改善する元素であり、
十分な強度と優れた熱間加工性を得るためにはSi
を1.2％以上含有させる必要があり下限を1.2％と
した。しかし、3.0％を越えて含有させるとＮの
固溶限界を著しく低下させ、かつ、オーステナイ
トバランスを損うので上限を3.0％とした。
Crはステンレス鋼の基本元素であり、優れた
耐食性を得るためには少なくとも16％以上の含有
が必要である。しかし、Cr量の増加とともにフ
エライト量が増加し、22％を越えて含有させると
オーステナイトバランスを損うので上限を22％と
した。
Niはオーステナイト系ステンレス鋼の基本元
素であり、優れた耐食性とオーステナイト組織を
得るためには8.4％以上の含有が必要である。し
かし15％を越えて含有させると熱間加工性を損
い、かつＮの固溶限を低下させるので上限を15％
とした。
Mnは本発明鋼においてSi、Cr、Ni量に応じて
Ｎの固溶限を高めるために含有させる主要な元素
である。
本発明鋼のＮ、Si含有量では少なくとも2.3％
以上の含有が必要である。しかし5.5％を越えて
含有させると熱間加工性を損うので上限を5.5％
とした。
Nbは結晶粒を微細化して、強度、熱間加工性
を向上させる元素で、これら効果を発揮させるに
は0.05％以上の含有が必要である。しかし1.0％
を越えて含有させると炭窒化物の析出量が増加し
逆に加工性を損うのでその上限を1.0％とした。
Mo、Cu、Ｖはいずれも本発明鋼の耐食性をさ
らに改善する元素であり、その効果を発揮させる
にはMoは0.2％以上、Cuは0.2％以上、Ｖは0.05
％以上の含有が必要である。しかし、Moを3.0％
を越え、Ｖを0.50％越えて含有させるとオーステ
ナイトバランスを損い、Cuは3.0％越えて含有さ
せると強度を大きく低下させるのでその上限は
Mo3.0％、Cu3.0％、V0.50％とした。
つぎに本発明鋼の特徴を従来鋼と比べ実施例で
もつて明らかにする。
第１表は、これらの供試鋼の化学成分を示すも
のである。
The present invention relates to high-strength austenitic stainless steel with excellent corrosion resistance and workability, which is used in various plants such as chemical, seawater, and nuclear power plants, food products, machinery, ship machinery, and the like. Austenitic stainless steel is widely used because of its excellent corrosion resistance, heat resistance, workability, and mechanical properties. Recently, as machines and structures have become larger, there has been a strong demand for improved strength of structural stainless steel. To meet this requirement, an austenitic stainless steel with improved strength is made by adding approximately 0.15% N to SUS304.
SUS304N 1 , SUS304N 2 with approximately 0.1% Nb added to this SUS304N 1 , and 22Cr―13Ni―
5Mn-0.3N steel and 20Cr-6Ni-9Mn-0.3M steel are known. The strength of these steels after solution heat treatment is the same as that of the former two.
The yield strength of SUS304N 1 and SUS304N 2 is about 35Kg/mm 2 ,
The tensile strength is around 75Kg/ mm2 , which is not necessarily sufficient strength, and the latter two types of steel have a yield strength of 45Kg/mm2.
It has a nearly satisfactory strength of approximately Kg/mm 2 and tensile strength of 80 Kg/mm 2 or more. However, since the latter two steels contain a large amount of N (0.3%), they are more susceptible to stress corrosion cracking than SUS304, which is a major drawback as austenitic stainless steels for high-strength structures. Furthermore, it has the disadvantage of poor hot workability due to its high Mn content. Also, although it is not directly aimed at high strength,
25Cr-13Ni-0.3N is a steel with high strength.
-1Mo steel and 17Cr-8Ni-8Mn-4Si-0.15N steel are known. However, these have a yield strength of 40Kg/mm 2
The tensile strength is about 78 kg/mm 2 , which is far short of the required strength. Furthermore, the former steel is
Cr steel, and the latter steel is a high Si steel, so both have the disadvantage of poor hot workability. The present invention overcomes these drawbacks of conventional steels, and as a result of various studies conducted by the present inventors, it has been found that simply increasing the amount of N to increase the strength of austenitic stainless steel increases the stress corrosion cracking susceptibility. Defects arise. Therefore, in addition to N,
The hot workability of steel with a tensile strength of 80 Kg/mm 2 was investigated by increasing the amount of Si and by combining Si and N.
As shown in Fig. 1, the torsion value increases as the Si content increases, shows an almost satisfactory value at 1.2% Si, and remains almost constant at 1.5% Si.
It was found that workability was improved when N was used in combination with Si. Furthermore, the stress corrosion cracking resistance of steel with the same composition as above was investigated. The results are shown in FIG. 2, and it was found that this improved as the amount of Si increased and the amount of N decreased. Based on the above results, we have developed a new type of high-strength austenitic stainless steel that increases the amount of Si in addition to N and utilizes the solid solution strengthening effect of Si and N. It was discovered that compared to the conventional high-strength steel used, the workability is improved while maintaining the same strength, and it is possible to suppress an increase in stress corrosion cracking susceptibility. However, when the amount of Si is increased, the solid solubility limit of N is lowered, and the risk of bubble generation during solidification of the steel ingot increases. As a result of further research, the present inventors found that the problem could be solved by incorporating an appropriate amount of Mn and further adjusting the amount of Cr and Ni so that the amount of segregated delta ferrite during solidification was 2% or less. This is what we discovered. Furthermore, as a result of investigating the strength and hot workability of steel with the above composition containing 0.2% Nb,
As shown in Figure 3, the tensile strength is greatly improved compared to SUS304, and the torsion value is also slightly improved. It was discovered that this method improves hot workability while increasing strength. The steel of the present invention is a high-strength austenitic stainless steel that utilizes a combination of the solid solution strengthening effect of N and Si, developed based on these findings, and the strengthening effect due to grain refinement of Nb. In the present invention, as the second invention steel
Corrosion resistance is further improved by containing small amounts of Mo, Cu, and V. As described above, the steel of the present invention is a high-strength austenitic stainless steel with excellent corrosion resistance and workability, and is suitable for strength members of various large-scale plants used in harsh environments such as seawater, chemical, and nuclear power plants. be. The steel of the present invention will be explained in detail below. The first invention steel has a weight ratio of C0.04 to 0.07%,
Si1.2~3.0%, Mn2.3~5.5%, Ni8.4~15%,
It contains 16-22% Cr, 0.23-0.40% N, and 0.05-1.0% Nb, and the second invention steel has Mo0.2 in addition to the first invention steel.
~3.0%, Cu0.2~3.0%, V0.05~0.50% 1
The corrosion resistance of the first invention steel is further improved by containing one or more species. The reasons for limiting the composition of the steel of the present invention will be explained below. Like N, C is an important element that strengthens the substrate, and if it is less than 0.04%, it is insufficient for strengthening the substrate with carbide. On the other hand, C is an element that significantly impairs corrosion resistance, but the steel of the present invention contains Nb in an amount of 0.05 to 1.0%, and even if C is contained in an amount of 0.04% or more, the corrosion resistance hardly deteriorates. However, if the content exceeds 0.07%, corrosion resistance and hot workability will be impaired, so the upper limit was set at 0.07%. N is the most important strengthening element in the steel of the present invention, and is a strong austenite-forming element that significantly improves pitting corrosion resistance.In order to exhibit these properties, it must be contained at 0.23% or more, and the lower limit is 0.23. On the other hand, N is an element that increases stress corrosion cracking susceptibility, and if it is contained in excess of 0.40%, hot workability will be significantly impaired, so the upper limit was set at 0.40%. Si is one of the main elements that dissolves in geology and strengthens it, and a 1% Si content has a strengthening ability equivalent to a 0.08% N content. Furthermore, Si has corrosion resistance,
It is an element that also improves stress corrosion cracking susceptibility.
In order to obtain sufficient strength and excellent hot workability, Si
The lower limit was set at 1.2%. However, if the content exceeds 3.0%, the solid solubility limit of N will be significantly lowered and the austenite balance will be impaired, so the upper limit was set at 3.0%. Cr is a basic element of stainless steel, and in order to obtain excellent corrosion resistance, it must be contained at least 16%. However, as the amount of Cr increases, the amount of ferrite increases, and if the content exceeds 22%, the austenite balance will be impaired, so the upper limit was set at 22%. Ni is a basic element of austenitic stainless steel, and its content of 8.4% or more is required to obtain excellent corrosion resistance and an austenitic structure. However, if the content exceeds 15%, hot workability will be impaired and the solid solubility limit of N will be lowered, so the upper limit should be set at 15%.
And so. Mn is a main element contained in the steel of the present invention in order to increase the solid solubility limit of N depending on the amounts of Si, Cr, and Ni. The N and Si content of the steel of the present invention is at least 2.3%
The above content is necessary. However, if the content exceeds 5.5%, hot workability will be impaired, so the upper limit should be set at 5.5%.
And so. Nb is an element that refines crystal grains and improves strength and hot workability, and in order to exhibit these effects, the content must be 0.05% or more. But 1.0%
If the content exceeds 1.0%, the amount of precipitated carbonitrides will increase and workability will be adversely affected, so the upper limit was set at 1.0%. Mo, Cu, and V are all elements that further improve the corrosion resistance of the steel of the present invention, and in order to exhibit their effects, Mo should be 0.2% or more, Cu should be 0.2% or more, and V should be 0.05%.
% or more is required. However, Mo 3.0%
If the V content exceeds 0.50%, the austenite balance will be impaired, and if the Cu content exceeds 3.0%, the strength will decrease significantly, so the upper limit is
Mo3.0%, Cu3.0%, V0.50%. Next, the characteristics of the steel of the present invention will be clarified through examples in comparison with conventional steel. Table 1 shows the chemical composition of these test steels.
【表】
第１表においてA1〜A6は従来鋼で、A1は
SUS304、A2はSUS304N1、A3はSUS304N2A4
は22Cr―13Ni―5Mn―0.3N―2Mo―0.2V鋼、A5
は17Cr―8Ni―8Mn―4Si―0.2N鋼、A6は25Cr―
13Ni―0.3N―1Mo鋼である。
B1〜B5は本発明鋼で、B1〜B3は第１発明鋼、
B4、B5は第２発明鋼で、B6、B7は比較鋼であ
る。
第２表は第１表の固溶体化熱処理を施したA1
〜A6鋼、B1〜B7鋼の強度、熱間加工性および耐
食性を示したものである。
強度については、JIS4号試験片を用いて耐力、
引張り強さ、伸びを測定した。
加工性については80％の熱間据え込み試験にて
評価し、試験個数10ケとし、割れ発生率を示した
ものである。
耐食性については、JIS試験法に基づいて耐孔
食性、耐応力腐食割れ性、耐硫酸性について評価
した。耐孔食性は40℃の４％FeCl溶液中に24Hr
浸漬した場合の腐食減量を示したもので、耐応力
腐食割れ性感受性は沸騰した42％MgCl溶液中に
浸漬した場合、応力25Kg/mm2下で破断までの時間
（分）を示したもので、耐硫酸性については沸騰
した５％H2SO4溶液中に6Hr浸漬した場合の腐食
減量を示したものである。[Table] In Table 1, A1 to A6 are conventional steels, and A1 is
SUS304, A2 is SUS304N 1 , A3 is SUS304N 2 A4
is 22Cr―13Ni―5Mn―0.3N―2Mo―0.2V steel, A5
is 17Cr―8Ni―8Mn―4Si―0.2N steel, A6 is 25Cr―
It is 13Ni-0.3N-1Mo steel. B1 to B5 are the invention steels, B1 to B3 are the first invention steels,
B4 and B5 are second invention steels, and B6 and B7 are comparative steels. Table 2 shows A1 that has been subjected to the solid solution heat treatment shown in Table 1.
- This shows the strength, hot workability, and corrosion resistance of A6 steel and B1 to B7 steel. Regarding the strength, we used JIS No. 4 test pieces to measure the yield strength,
Tensile strength and elongation were measured. Workability was evaluated using an 80% hot upsetting test, with 10 pieces being tested, and the crack occurrence rate is shown. Regarding corrosion resistance, pitting corrosion resistance, stress corrosion cracking resistance, and sulfuric acid resistance were evaluated based on JIS test methods. Pitting corrosion resistance is 24Hr in 4% FeCl solution at 40℃
It shows the corrosion loss when immersed, and the stress corrosion cracking resistance shows the time (minutes) until rupture under a stress of 25 Kg/mm 2 when immersed in a boiling 42% MgCl solution. Regarding sulfuric acid resistance, the corrosion weight loss when immersed in a boiling 5% H 2 SO 4 solution for 6 hours is shown.
【表】
第２表から知られるように、従来鋼であるA1
鋼は耐食性、熱間加工性については優れているが
強度については耐力24Kg/mm2、引張り強さ61Kg/mm2
と低いものである。A1鋼にＮあるいはＮとNbを
含有させたA2、A3鋼はA1鋼同様耐食性、熱間加
工性について優れており、強度についても耐力31
Kg／mm2、37Kg/mm2、引張り強さ71Kg/mm2、75Kg/mm2と
A1鋼に比べ相当の向上が認められるが高強度オ
ーステナイト系ステンレス鋼としては、いま一つ
強度不足である。
また、A4鋼については耐力48Kg/mm2、引張り強
さ85Kg/mm2と満足し得る強度と、良好な耐食性を
有しているが、熱間加工性については80％の熱間
据え込み試験において20％の割れが発生してい
る。
A5、A6鋼については強度が耐力38〜41Kg/mm2、
引張り強さ77〜78Kg/mm2と今一歩不足し熱間加工
性についても80％の熱間据え込み試験で10〜20％
の割れが発生しており、熱間加工性も劣つている
ものである。さらに耐応力腐食性についてもA4
鋼はSUS304であるA1鋼に比べて劣つており、
A4〜A6鋼は高強度耐食構造部材としてはまだ不
満足なものである。
これらに対して本発明鋼であるB1〜B5鋼は
Ｎ、Nb、Si、Mnを適宜に含有させるとともに
CrNi量を調整することにより強度については耐
力45Kg/mm2以上、引張り強さ80Kg/mm2以上と高強度
オーステナイト系ステンレス鋼として満足し得る
ものであり、熱間加工性についてはA1〜A3鋼な
みで、耐食性についてはA1〜A3鋼に比べさらに
優れたものである。
これからしても本発明鋼が強度のみならず熱間
加工性、耐食性についても非常に優れていること
がわかる。
上述の如く本発明鋼はＮ、Si、Mnを適宜に含
有させるとともにCr、Ni量を調整することによ
りSUS304のもつ熱間加工性、耐食性を損うこと
なく高強度を得ることに成功したもので海水、化
学、原子力等の過酷な使用環境で使用される各種
大型プラントの高強度耐食構造部材として極めて
高い実用性を有するものである。[Table] As is known from Table 2, conventional steel A1
Steel has excellent corrosion resistance and hot workability, but its strength is 24Kg/mm 2 in yield strength and 61Kg/mm 2 in tensile strength.
This is low. A2 and A3 steels, which are made by adding N or N and Nb to A1 steel, have excellent corrosion resistance and hot workability like A1 steel, and have a yield strength of 31
Kg/mm 2 , 37Kg/mm 2 , tensile strength 71Kg/mm 2 , 75Kg/mm 2
Although it is considerably improved compared to A1 steel, it still lacks strength as a high-strength austenitic stainless steel. In addition, A4 steel has satisfactory strength with a yield strength of 48 Kg/mm 2 and a tensile strength of 85 Kg/mm 2 , as well as good corrosion resistance. 20% cracking occurred. For A5 and A6 steel, the strength is 38-41Kg/mm 2 ,
Tensile strength is 77-78Kg/ mm2 , which is a step short, and hot workability is 10-20% in 80% hot upsetting test.
Cracks have occurred, and hot workability is also poor. Furthermore, regarding stress corrosion resistance, A4
The steel is inferior to A1 steel, which is SUS304,
A4 to A6 steel is still unsatisfactory as a high-strength, corrosion-resistant structural member. In contrast, B1 to B5 steels, which are the steels of the present invention, contain N, Nb, Si, and Mn appropriately.
By adjusting the amount of CrNi, the strength can be satisfied as a high-strength austenitic stainless steel with a yield strength of 45 Kg/mm 2 or more and a tensile strength of 80 Kg/mm 2 or more, and the hot workability is higher than that of A1 to A3 steel. In terms of corrosion resistance, it is even better than A1 to A3 steel. This shows that the steel of the present invention is excellent not only in strength but also in hot workability and corrosion resistance. As mentioned above, the steel of the present invention has succeeded in obtaining high strength without impairing the hot workability and corrosion resistance of SUS304 by appropriately containing N, Si, and Mn and adjusting the amounts of Cr and Ni. It has extremely high practicality as a high-strength, corrosion-resistant structural member for various large-scale plants used in harsh environments such as seawater, chemical, and nuclear power plants.
第１図は熱間加工性に及ぼすSi、Ｎの影響を示
した線図、第２図は耐応力腐食割れ性に及ぼす
SiNの影響を示す線図、第３図は強度と熱間加工
性に及ぼすNbの影響を示す線図である。
Figure 1 is a diagram showing the influence of Si and N on hot workability, and Figure 2 is a diagram showing the influence of Si and N on stress corrosion cracking resistance.
Figure 3 is a diagram showing the influence of SiN and Figure 3 is a diagram showing the influence of Nb on strength and hot workability.
Claims (1)
Mn2.3〜5.5％、Ni8.4〜15％、Cr16〜22％、
N0.23〜0.40％、Nb0.05〜1.0％を含有し、残部
Feならびに不純物元素からなることを特徴とす
る高強度オーステナイト系ステンレス鋼。 ２ 重量比にしてC0.04〜0.07％、Si1.2〜3.0％、
Mn2.3〜5.5％、Ni8.4〜15％、Cr16〜22％、
N0.23〜0.40％、Nb0.05〜1.0％を含有し、さらに
Mo0.2〜3.0％、Cu0.2〜3.0％、V0.05〜0.50％の
うち１種ないし２種以上を含有し、残部Feなら
びに不純物元素からなることを特徴とする高強度
オーステナイト系ステンレス鋼。[Claims] 1. C0.04 to 0.07%, Si 1.2 to 3.0% by weight,
Mn2.3~5.5%, Ni8.4~15%, Cr16~22%,
Contains N0.23~0.40%, Nb0.05~1.0%, the balance
High-strength austenitic stainless steel characterized by consisting of Fe and impurity elements. 2 C0.04~0.07%, Si1.2~3.0%, weight ratio
Mn2.3~5.5%, Ni8.4~15%, Cr16~22%,
Contains N0.23~0.40%, Nb0.05~1.0%, and
High-strength austenitic stainless steel containing one or more of Mo0.2-3.0%, Cu0.2-3.0%, and V0.05-0.50%, with the balance consisting of Fe and impurity elements. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6369280A JPS56158851A (en) | 1980-05-14 | 1980-05-14 | High-strength austenite stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6369280A JPS56158851A (en) | 1980-05-14 | 1980-05-14 | High-strength austenite stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56158851A JPS56158851A (en) | 1981-12-07 |
| JPH0118143B2 true JPH0118143B2 (en) | 1989-04-04 |
Family
ID=13236673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6369280A Granted JPS56158851A (en) | 1980-05-14 | 1980-05-14 | High-strength austenite stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56158851A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1707352A1 (en) | 2005-03-31 | 2006-10-04 | Fuji Photo Film Co., Ltd. | Method of producing a planographic printing plate |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57164971A (en) * | 1981-03-31 | 1982-10-09 | Sumitomo Metal Ind Ltd | Austenite steel with superior strength at high temperature |
| JPS60149748A (en) * | 1984-01-13 | 1985-08-07 | Nippon Steel Corp | Austenitic stainless steel having superior hot workability |
| DE3407305A1 (en) * | 1984-02-24 | 1985-08-29 | Mannesmann AG, 4000 Düsseldorf | USE OF A CORROSION-RESISTANT AUSTENITIC ALLOY FOR MECHANICALLY STRESSED, WELDABLE COMPONENTS |
| US5340534A (en) * | 1992-08-24 | 1994-08-23 | Crs Holdings, Inc. | Corrosion resistant austenitic stainless steel with improved galling resistance |
| SE506550C2 (en) * | 1994-11-02 | 1998-01-12 | Sandvik Ab | Use of an non-magnetic stainless steel in superconducting low temperature applications |
-
1980
- 1980-05-14 JP JP6369280A patent/JPS56158851A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1707352A1 (en) | 2005-03-31 | 2006-10-04 | Fuji Photo Film Co., Ltd. | Method of producing a planographic printing plate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56158851A (en) | 1981-12-07 |
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