JP5119605B2 - Ferritic stainless steel with excellent corrosion resistance of welds - Google Patents
Ferritic stainless steel with excellent corrosion resistance of welds Download PDFInfo
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Description
本発明は、耐食性、中でも溶接部の耐食性に優れたフェライト系ステンレス鋼に関するものである。 The present invention relates to a ferritic stainless steel having excellent corrosion resistance, particularly corrosion resistance of a welded portion.
JIS−SUS444を典型例とするフェライト系ステンレス鋼は、オーステナイト系ステンレス鋼と比較して、応力腐食割れ（SCC）の感受性が小さいという特徴から、電気温水器等の材料として使用されている。 Ferritic stainless steel, typically JIS-SUS444, is used as a material for electric water heaters and the like because it is less susceptible to stress corrosion cracking (SCC) than austenitic stainless steel.
さて、水道水には、衛生対策のため、残留塩素が含まれているが、この残留塩素による酸化作用による材料の腐食が問題となる。特に、溶接を施した製品においては、母材部に比較し、溶接部（溶接金属および溶接熱影響部）の耐食牲が問題となることが多い。 Now, tap water contains residual chlorine as a sanitary measure, but corrosion of the material due to oxidation by this residual chlorine becomes a problem. In particular, in a welded product, the corrosion resistance of the welded portion (welded metal and weld heat affected zone) often becomes a problem as compared with the base material portion.
かような耐食性を改善する技術として、例えば特許文献１では、高純度化精錬技術を用いて、ＰとＳ並びにＣとＮを低減することにより、耐食性を向上させる方法が開示されている。 As a technique for improving such corrosion resistance, for example, Patent Document 1 discloses a method for improving corrosion resistance by reducing P and S and C and N using a high-purification refining technique.
また、特許文献２では、Tiの添加量を制限し、かつTiとAlを複合添加し、さらに適正量のCuを添加することにより、溶接部の耐食性を向上させる技術が開示されている。
近年、衝生対策の強化が求められ、建築物衛生法およびビル管理法が2003年に改正され、特定建築物については、給湯水についても0.1mg／ｌ以上の塩素の残留が求められることになった。 In recent years, there has been a demand for strengthening countermeasures, and the Building Sanitation Law and Building Management Law have been revised in 2003, and for specified buildings, there must be a residual chlorine of 0.1 mg / l or more in hot water. became.
ここに、給湯システムで残留塩素が消耗することを考慮すると、給湯水に更なる塩素の添加が必要になる。このような使途においては、従来の特許文献１や特許文献２に開示の技術で対処することは難しく、十分な溶接部の耐食性を確保できないことが懸念される。 Considering that residual chlorine is consumed in the hot water supply system, it is necessary to add further chlorine to the hot water supply water. In such a usage, it is difficult to cope with the techniques disclosed in the conventional Patent Document 1 and Patent Document 2, and there is a concern that sufficient corrosion resistance of the welded portion cannot be ensured.
本発明は、残留塩素の増加を所期して塩素の添加量を増加した温水中での使用においても、十分な溶接部の耐食性を有する、特に温水器に用いて好適なフェライト系ステンレス鋼を提供しようとするものである。 The present invention provides a ferritic stainless steel that has sufficient corrosion resistance of a welded part, and is particularly suitable for use in a water heater, even when used in warm water in which the amount of added chlorine is increased by increasing residual chlorine. It is something to try.
発明者らは、上記した課題を達成するために、溶接部の耐食性に及ぼす鋼の化学成分の影響について、綿密な調査、そして検討を行った。その結果、次のような知見を得た。
(I)母材部および溶接部の耐食性は、Cr、MoおよびSi量を増加することにより向上するが、Si量の一定量以上の添加は溶接金属部の物性を劣化させるため、用途に応じた制限が必要である。
(II)溶接部の耐食性は、TiとAlの添加量を制限することにより向上する。
(III)溶接部の耐食性は、適正量のＯを添加することにより向上する。
In order to achieve the above-mentioned problems, the inventors have conducted a thorough investigation and examination on the influence of the chemical composition of steel on the corrosion resistance of welds. As a result, the following knowledge was obtained.
(I) The corrosion resistance of the base metal part and the welded part is improved by increasing the amount of Cr, Mo and Si, but addition of a certain amount or more of Si content deteriorates the physical properties of the welded metal part. Restrictions are needed.
(II) The corrosion resistance of the weld is improved by limiting the amount of Ti and Al added.
(III) The corrosion resistance of the weld is improved by adding an appropriate amount of O.
本発明は、上述した知見に基づき、さらに検討を重ねて完成されたものである。すなわち、本発明の要旨は次のとおりである。
質量％で
Ｃ：0.020％以下、Si：0.32〜1.00％、Mn：0.17％以下、Ｐ：0.040％以下、Ｓ：0.010％以下、Cr：17.0〜31.0％、Ni：0.60％以下、Al：0.08％以下、Ｎ：0.020％以下、Ｏ：0.0020〜0.0150％、Mo：0.3〜3.0％、Ti：0.30％以下およびNb：0.10〜0.50％を含有し、
Cr+3.3Mo≧22.0並びに
４Al＋Ti≦0.32
を満足し、残部Fe及びその他不可避的不純物からなることを特徴とする溶接部の耐食性に優れたフェライト系ステンレス鋼。
The present invention has been completed through further studies based on the above-described findings. That is, the gist of the present invention is as follows.
By mass% C: 0.020% or less, Si: 0.32 to 1.00%, Mn: 0.17 % or less, P: 0.040% or less, S: 0.010% or less, Cr: 17.0 to 31.0%, Ni: 0.60% or less, Al: 0.08 %: N: 0.020% or less, O: 0.0020 to 0.0150%, Mo: 0.3 to 3.0%, Ti: 0.30% or less and Nb: 0.10 to 0.50%,
Cr + 3.3Mo ≧ 22.0 and 4Al + Ti ≦ 0.32
And ferritic stainless steel excellent in corrosion resistance of welds, characterized by comprising the balance Fe and other inevitable impurities.
本発明によれば、フェライト系ステンレス鋼における溶接部の耐食性を従来材に比較して大幅に向上させたことから、特に温水器用材料として使用した場合、水道水中の残留塩素量を増加しても、溶接部の腐食による損傷を格段に低減することができ、産業上、格段の効果を奏する。 According to the present invention, since the corrosion resistance of the welded portion in ferritic stainless steel has been greatly improved compared to conventional materials, even when used as a water heater material, even if the amount of residual chlorine in tap water is increased. The damage due to the corrosion of the welded portion can be remarkably reduced, and there is a remarkable effect industrially.
以下、本発明を具体的に説明する。
まず、本発明において鋼の化学成分を上記した範囲に限定した理由について説明する。なお、成分に関する「％」表示は、特に断らない限り質量％を意味するものとする。
Ｃ：0.020％以下
Ｃは、Crと結合してCr炭化物を形成しやすい。従って、溶接時、熱影響部にCr炭化物が形成されると、粒界腐食の原因となるため、Ｃは低い程望ましい。そこで、本発明では、Ｃを0.020％以下に限定した。
Hereinafter, the present invention will be specifically described.
First, the reason why the chemical components of steel are limited to the above-described range in the present invention will be described. In addition, unless otherwise indicated, "%" display regarding a component shall mean the mass%.
C: 0.020% or less C is liable to form Cr carbide by combining with Cr. Therefore, when Cr carbide is formed in the heat-affected zone during welding, it causes grain boundary corrosion, so C is preferably as low as possible. Therefore, in the present invention, C is limited to 0.020% or less.
Si：0.32〜1.00％
Siは、本発明において重要な元素である。すなわち、Siは、溶接部の耐食性向上に有効な元素であり、通常はその含有量に比例して効果を有する。そのために、0.32％以上で添加する。より好ましくは0.6％以上添加すると良い。一方、Siは溶接部の成形性や靭性を低下させるため、上限を1.00％とした。
Si: 0.32 to 1.00%
Si is an important element in the present invention. That is, Si is an element effective for improving the corrosion resistance of the welded portion, and usually has an effect in proportion to its content. Therefore, add at 0.32 % or more. More preferably, 0.6% or more is added. On the other hand, Si lowers the formability and toughness of the weld zone, so the upper limit was made 1.00%.
Mn：0.17％以下
Mnは、鋼中に存在するＳと結合して、可溶性硫化物であるMnSを形成し、耐食性を低下させる。そこで、本発明では、Mnを0.17％以下に限定した。
Mn: 0.17 % or less
Mn combines with S present in the steel to form MnS, which is a soluble sulfide, and lowers the corrosion resistance. Therefore, in the present invention, Mn is limited to 0.17 % or less.
Ｐ：0.040％以下
Ｐは、耐食性に有害な元素である。特に、0.040％を超えると顕著になる。このため、Ｐは0.040％以下に限定した。
P: 0.040% or less P is an element harmful to corrosion resistance. In particular, it becomes remarkable when it exceeds 0.040%. For this reason, P was limited to 0.040% or less.
Ｓ：0.010％以下
Ｓは、耐食性に有害な元素である。特に、0.010％を超えると顕著になる。このため、Ｓは0.010％以下に限定する。
S: 0.010% or less S is an element harmful to corrosion resistance. In particular, it becomes remarkable when it exceeds 0.010%. For this reason, S is limited to 0.010% or less.
Cr：17.0〜31.0％
Crは、耐食性を向上させる元素であり、フェライト系ステンレス鋼では不可欠の元素である。このような効果は17.0％以上の含有で顕著となる。一方、31.0％を超えて含有すると、靭性が顕著に低下する。このため、Crは17.0〜31.0％の範囲に限定する。
Cr: 17.0-31.0%
Cr is an element that improves corrosion resistance, and is an indispensable element in ferritic stainless steel. Such an effect becomes remarkable when the content is 17.0% or more. On the other hand, when it contains exceeding 31.0%, toughness will fall remarkably. For this reason, Cr is limited to the range of 17.0 to 31.0%.
Ni：0.6％以下
Niは、靭性の向上に有利に寄与する元素であり、好ましくは0.1％以上で含有させる。しかし、0.6％を超えて含有させると、応力腐食割れ感受性が高くなる。このため、Niは0.6％以下に限定することが好ましい。
Ni: 0.6% or less
Ni is an element that advantageously contributes to the improvement of toughness, and is preferably contained at 0.1% or more. However, if the content exceeds 0.6%, the stress corrosion cracking sensitivity becomes high. For this reason, it is preferable to limit Ni to 0.6% or less.
Al：0.08％以下
Alは、本発明の中で重要な元素であり、Alを脱酸剤として作用させるためには、0.02％以上で含有させることが好ましい。一方、溶接溶け込み性を低下させるため、十分な溶接裏ビード幅を得るためには、溶接入熱を大きくする必要がある。このため、本発明ではAlは0.08％以下に限定した。ここで、溶接溶け込み性とは、溶接金属（溶融金属）の板厚方向への流れ込み易さであり、一般に裏ビード／表ビードで評価される。この値が大きいほど溶融金属が板厚方向に流れることになり、溶け込み性が良いということになる。いいかえると、少量の電流値で、裏ビート幅が広いほど溶接での溶融金属が板厚方向へ流れ込み易く、溶接溶け込み性の良い材料となる。
Al: 0.08% or less
Al is an important element in the present invention. In order to cause Al to act as a deoxidizer, it is preferable to contain Al at 0.02% or more. On the other hand, in order to reduce weld penetration, it is necessary to increase welding heat input in order to obtain a sufficient weld back bead width. For this reason, in the present invention, Al is limited to 0.08% or less. Here, the weld penetration is the ease with which the weld metal (molten metal) flows in the thickness direction, and is generally evaluated by the back bead / front bead. The larger this value, the more the molten metal flows in the thickness direction, and the better the penetration. In other words, with a small amount of current value, the wider the back beat width, the easier the molten metal in welding flows into the plate thickness direction, and the better the weld penetration.
Ｎ：0.020％以下
Ｎは、Crと結合してCr窒化物を形成しやすい。溶接時、熱影響部にCr窒化物が形成されると粒界腐食の原因となるため、Ｎは低い程望ましい。そこで、本発明では、Ｎを0.020％以下に限定した。
N: 0.020% or less N is liable to form Cr nitride by combining with Cr. When Cr nitride is formed in the heat-affected zone during welding, it causes grain boundary corrosion, so N is preferably as low as possible. Therefore, in the present invention, N is limited to 0.020% or less.
Ｏ：0.0020〜0.0150％
Ｏは、本発明の中で重要な元素である。Ｏは、溶接溶け込みを向上させる元素である。一方、多量の添加は介在物を増加させ、耐食性の劣化が顕著となる。このため、Ｏは0.0020〜0.0150％の範囲に限定する。
O: 0.0020 to 0.0150%
O is an important element in the present invention. O is an element that improves welding penetration. On the other hand, addition of a large amount increases inclusions, and the deterioration of corrosion resistance becomes remarkable. For this reason, O is limited to the range of 0.0020 to 0.0150%.
Mo：0.3〜3.0％
Moは、耐食性を顕著に向上させる元素である。このような効果は0.3％以上の含有で顕著となる。一方、3.0％を超えて含有すると、靭性が顕著に低下する。このため、Moは0.3〜3.0％の範囲に限定することが好ましい。
Mo: 0.3-3.0%
Mo is an element that significantly improves the corrosion resistance. Such an effect becomes remarkable when the content is 0.3% or more. On the other hand, when it contains exceeding 3.0%, toughness will fall remarkably. For this reason, it is preferable to limit Mo to the range of 0.3 to 3.0%.
Nb：0.10〜0.50％
Nbは、Crよりも優先的に窒化物を形成する。従って、溶接時、熱影響部にCr窒化物が形成されるのを防ぎ、粒界腐食を抑制できる。そのためには、0.10％以上の含有が必要である。一方、0.50％を超えると逆に耐食性を低下させる。よって、Nbは0.10〜0.50％の範囲に限定する。
Nb: 0.10 to 0.50%
Nb forms nitrides preferentially over Cr. Therefore, it is possible to prevent the formation of Cr nitride in the heat affected zone during welding and to suppress intergranular corrosion. For that purpose, the content of 0.10% or more is necessary. On the other hand, if it exceeds 0.50%, the corrosion resistance is reduced. Therefore, Nb is limited to a range of 0.10 to 0.50%.
Ti：0.30％以下
Tiは、本発明において重要な元素である。Tiは、Nbと同様にCrよりも優先的に炭窒化物を形成する。従って、溶接時、熱影響部にCr炭窒化物が形成されるのを防ぎ、粒界腐食を抑制できる。TiとNbの合計が、化学当量的な関係から、８×（C＋N）％以上となるように添加するとよい。Tiは、溶接溶け込み性を低下させるので、十分な溶接裏ビート幅を得るためには、溶接入熱を大きくする必要がある。このため、本発明ではTiは0.30％以下に限定した。
Ti: 0.30% or less
Ti is an important element in the present invention. Ti, like Nb, forms carbonitride preferentially over Cr. Therefore, during welding, the formation of Cr carbonitride in the heat affected zone can be prevented, and intergranular corrosion can be suppressed. It is preferable to add so that the total of Ti and Nb is 8 × (C + N)% or more because of the chemical equivalent. Ti lowers the weld penetration, so it is necessary to increase the welding heat input in order to obtain a sufficient weld back beat width. Therefore, in the present invention, Ti is limited to 0.30% or less.
以上、基本成分の適正組成範囲について説明したが、本発明では各成分が上記の組成範囲を単に満足しているだけでは不十分で、下記式（1）および（2）の関係も併せて満足する必要がある。
記
Cr+3.3Mo≧22.0・・・（1）
４Al＋Ti≦0.32・・・（2）
上記式（1）は、母材部および溶綾部の耐食性を得るために必要な条件である。すなわち、ステンレス鋼特有の不動態被膜はCr量とMo量が多いほど安定であり、特にMoはその効果が大きく、Cr量の3.3倍の効果があることが知られている。このため、本発明の温水器用途としては、Cr＋3.3Moを少なくとも22.0以上にすることが肝要である。
Although the proper composition range of the basic component has been described above, in the present invention, it is not sufficient that each component simply satisfies the above composition range, and the relationship of the following formulas (1) and (2) is also satisfied. There is a need to.
Record
Cr + 3.3Mo ≧ 22.0 ... (1)
4Al + Ti ≦ 0.32 (2)
The above formula (1) is a condition necessary for obtaining the corrosion resistance of the base material portion and the melted portion. In other words, the passive film unique to stainless steel is more stable as the Cr content and the Mo content increase. In particular, Mo has a large effect and is known to be 3.3 times as effective as the Cr content. For this reason, it is important for Cr + 3.3Mo to be at least 22.0 or more for the water heater application of the present invention.
また、上記式（2）は、溶接部の耐食性を得るために必要な条件である。AlとTiはいずれも溶接溶け込み性を劣化させる元素である。TiとAlの共存により、溶接溶け込み性は著しく劣化する。TiとAlが共存する場合、十分な溶接裏ビード幅を得るためには、溶接入熱を大きくする必要がある。上掲式（2）の範囲外のAlとTiを含有する鋼に対し、大入熱で溶接した溶接部の耐食性は、若しく劣化するため、上掲式（2）を満足する必要がある。この原因として、AlやTi系介在物により耐食性が劣化すること、大入熱で溶接すると溶接部のスケール生成が著しくなり、溶接金属あるいは溶接熱影響部と溶接スケールによる腐食隙間の形成が促進されること、が推察される。
従って、上掲式（1）、〈2〉の関係を満足させることによって、溶接部の耐食性を向上することができる。
Moreover, said Formula (2) is conditions required in order to acquire the corrosion resistance of a welding part. Al and Ti are both elements that degrade the weld penetration. Coexistence of Ti and Al significantly deteriorates weld penetration. When Ti and Al coexist, it is necessary to increase the welding heat input in order to obtain a sufficient weld back bead width. The corrosion resistance of welds welded with high heat input to steel containing Al and Ti outside the range of the above formula (2) deteriorates to a young level, so it is necessary to satisfy the above formula (2) . This is because the corrosion resistance deteriorates due to Al and Ti inclusions, and when welding is performed with high heat input, scale formation of the welded portion becomes significant, and the formation of corrosion gaps between the weld metal or weld heat affected zone and the weld scale is promoted. Is inferred.
Therefore, the corrosion resistance of the welded portion can be improved by satisfying the relationship of the above formulas (1) and <2>.
上記した成分以外の残部は、Feおよび不可避的不純物である。不可避的不純物としては、Mg：0.0020％以下およびCa：0.0020％以下は許容できる。 The balance other than the above components is Fe and inevitable impurities. As unavoidable impurities, Mg: 0.0020% or less and Ca: 0.0020% or less are acceptable.
次に、本発明鋼の好適製造方法について説明する。
上記した成分組成の溶鋼を、転炉、電気炉または真空溶解炉等の公知の方法で溶製し、連続鋳造法あるいは造魂・分塊法により鋼素材（スラブ）とする。この鋼素材を、その後加熱するか、あるいは加熱することなく直接、熱間圧延して熱延板とする。熱延板には、通常、熱延板焼鈍が施されるが、用途によっては熱延板焼鈍を省略してもよい。ついで、酸洗後、冷間圧延により冷延板としたのち、再結晶焼鈍を施して製品とする。
Next, the suitable manufacturing method of this invention steel is demonstrated.
Molten steel having the above-described component composition is melted by a known method such as a converter, electric furnace, or vacuum melting furnace, and is made into a steel material (slab) by a continuous casting method or a soul-making / bundling method. This steel material is then heated or directly hot-rolled without heating to form a hot-rolled sheet. The hot-rolled sheet is usually subjected to hot-rolled sheet annealing, but depending on the application, the hot-rolled sheet annealing may be omitted. Next, after pickling, the sheet is cold-rolled by cold rolling, and then subjected to recrystallization annealing to obtain a product.
以下、実施例に基づいて、本発明をさらに詳しく説明する。
表１に示す成分組成になる鋼（No.1〜10が発明例、No.11〜22が比較例、No.23〜24が従来例）を、小型真空溶解炉で溶製し、50kgの鋼魂とした。これらの鋼塊を、1050〜1250℃に加熱後、仕上げ温度：750〜950℃および巻取り温度：650〜850℃の条件で熱間圧延を施して4.0mm厚の熱延板とした。ついで、これらの熱延板の一部に対しては800〜1000℃の熱延板焼鈍を施した後、酸洗してから、冷間圧延により板厚1.0mmの冷延板とし、再結晶焼鈍を施した。
Hereinafter, the present invention will be described in more detail based on examples.
Steel having the composition shown in Table 1 (No. 1-10 is an invention example, No. 11-22 is a comparative example, No. 23-24 is a conventional example) is melted in a small vacuum melting furnace, and 50 kg Steel soul. These steel ingots were heated to 1050 to 1250 ° C., and then hot-rolled under conditions of finishing temperature: 750 to 950 ° C. and winding temperature: 650 to 850 ° C. to obtain 4.0 mm thick hot rolled sheets. Next, after subjecting some of these hot-rolled sheets to 800-1000 ° C hot-rolled sheet annealing, pickling, and then cold-rolling to a cold-rolled sheet with a thickness of 1.0 mm, recrystallization Annealed.
上記のようにして得られた各鋼板から試験片を採取し、その試験片にビード・オン・プレートのティグ溶接を下記条件にしたがって行った。裏ビード幅が３mm以上になるように、溶接電流を制御した。評価面は、裏ビード面とした。
記
溶接電圧：10Ｖ
溶接電流：90〜110Ａ
溶接速度：600mm／min
電極:1.6mmタングステン電極
シールドガス：表ビード側 Ar 20ｌ／min
：裏ビード側 Ar＋２％02 20ｌ／min
Test pieces were collected from each steel plate obtained as described above, and bead-on-plate TIG welding was performed on the test pieces according to the following conditions. The welding current was controlled so that the back bead width was 3 mm or more. The evaluation surface was a back bead surface.
Welding voltage: 10V
Welding current: 90-110A
Welding speed: 600mm / min
Electrode: 1.6 mm tungsten electrode Shielding gas: Front bead side Ar 20 l / min
: Back bead side Ar + 2% 0 2 20 l / min
次に、温水器環境での耐食性を調査するために、溶接された試験片を、浸漬試験に供した。試験液には、80℃に保持した0.1％NaCl＋0.05％CuC12水溶液を用いた。試験液に、溶接された試験片を30日間浸漬し、溶接部に発生した孔食の最大孔食深さを測定した。そして、溶接部の耐食性を以下の基準で評価した。
Ａ：最大孔食探さが10μm未満
Ｂ：最大孔食深さが10μm以上、20μm未満
Ｃ：最大孔食深さが20μm以上、100μm未満
Ｄ：最大孔食深さが100μm以上
Next, in order to investigate the corrosion resistance in the water heater environment, the welded test piece was subjected to an immersion test. The test solution was used 0.1% NaCl + 0.05% CuC1 2 aqueous solution was maintained at 80 ° C.. The welded specimen was immersed in the test solution for 30 days, and the maximum pitting depth of pitting corrosion that occurred in the weld was measured. And the corrosion resistance of the welded part was evaluated according to the following criteria.
A: Maximum pitting corrosion search is less than 10 μm B: Maximum pitting corrosion depth is 10 μm or more, less than 20 μm C: Maximum pitting corrosion depth is 20 μm or more, less than 100 μm D: Maximum pitting corrosion depth is 100 μm or more
この耐食性の評価結果を表２に示すように、本発明例はいずれも優れた耐食性を有するものであった。一方、本発明の範囲を外れる比較例及び従来例は耐食性が劣る結果となった。 As shown in Table 2, the results of evaluation of the corrosion resistance are shown in Table 2. All of the inventive examples had excellent corrosion resistance. On the other hand, the comparative example and the conventional example outside the scope of the present invention resulted in poor corrosion resistance.
Claims (1)
Ｃ：0.020％以下、
Si：0.32〜1.00％、
Mn：0.17％以下、
Ｐ：0.040％以下、
Ｓ：0.010％以下、
Cr：17.0〜31.0％、
Ni：0.60％以下、
Al：0.08％以下、
Ｎ：0.020％以下、
Ｏ：0.0020〜0.0150％、
Mo：0.3〜3.0％、
Ti：0.30％以下および
Nb：0.10〜0.50％
を含有し、
Cr+3.3Mo≧22.0並びに
４Al＋Ti≦0.32
を満足し、残部Fe及びその他不可避的不純物からなることを特徴とする溶接部の耐食性に優れたフェライト系ステンレス鋼。 In mass% C: 0.020% or less,
Si: 0.32 to 1.00%
Mn: 0.17 % or less,
P: 0.040% or less,
S: 0.010% or less,
Cr: 17.0-31.0%,
Ni: 0.60% or less,
Al: 0.08% or less,
N: 0.020% or less,
O: 0.0020 to 0.0150%,
Mo: 0.3-3.0%,
Ti: 0.30% or less and
Nb: 0.10 to 0.50%
Containing
Cr + 3.3Mo ≧ 22.0 and 4Al + Ti ≦ 0.32
And ferritic stainless steel excellent in corrosion resistance of welds, characterized by comprising the balance Fe and other inevitable impurities.
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| EP2100983B1 (en) | 2007-01-12 | 2012-10-31 | JFE Steel Corporation | Ferritic stainless steel sheet for water heater excellent in corrosion resistance at welded part and steel sheet toughness |
| JP2009097079A (en) * | 2007-09-27 | 2009-05-07 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel having excellent atmospheric corrosion resistance |
| WO2009041430A1 (en) * | 2007-09-27 | 2009-04-02 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic stainless steel having excellent atmospheric corrosion resistance |
| JP5489759B2 (en) | 2009-02-09 | 2014-05-14 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel with few black spots |
| JP5676896B2 (en) * | 2009-03-27 | 2015-02-25 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel with excellent local corrosion resistance |
| JP5793283B2 (en) | 2010-08-06 | 2015-10-14 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel with few black spots |
| KR101669740B1 (en) | 2011-11-30 | 2016-10-27 | 제이에프이 스틸 가부시키가이샤 | Ferritic stainless steel |
| CN104508168B (en) | 2012-09-24 | 2017-09-26 | 杰富意钢铁株式会社 | Ferrite-group stainless steel |
| ES2662417T3 (en) | 2012-10-22 | 2018-04-06 | Jfe Steel Corporation | Ferritic stainless steel and method of manufacturing it |
| MY160981A (en) | 2013-07-29 | 2017-03-31 | Jfe Steel Corp | Ferritic stainless steel having excellent corrosion resistance of weld zone |
| JP7156342B2 (en) * | 2020-02-05 | 2022-10-19 | Ｊｆｅスチール株式会社 | Ferritic stainless steel plate for thin-walled pipes and thin-walled pipes using the same |
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| JPS5399024A (en) * | 1977-02-10 | 1978-08-30 | Kawasaki Steel Co | Ferritic stainless steel giving tenacious welded zone |
| JP2739531B2 (en) * | 1991-09-17 | 1998-04-15 | 日新製鋼株式会社 | Ferritic stainless steel with excellent weld corrosion resistance |
| JP3127272B2 (en) * | 1992-07-15 | 2001-01-22 | 新日本製鐵株式会社 | Manufacturing method of high corrosion resistant ferritic stainless steel sheet |
| KR100240741B1 (en) * | 1994-01-26 | 2000-01-15 | 에모또 간지 | Method of manufacturing stainless steel sheet of high corrosion resistance |
| JP3450959B2 (en) * | 1996-02-14 | 2003-09-29 | 新日本製鐵株式会社 | Ferritic stainless steel with excellent weldability |
| JP3350343B2 (en) * | 1996-04-05 | 2002-11-25 | 新日本製鐵株式会社 | Method for producing ferritic stainless steel to prevent surface flaws from occurring during hot rolling |
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| JPH11323502A (en) * | 1998-05-12 | 1999-11-26 | Sumitomo Metal Ind Ltd | Ferritic stainless steel excellent in workability and toughness and slab thereof |
| JP3446667B2 (en) * | 1999-07-07 | 2003-09-16 | 住友金属工業株式会社 | Ferritic stainless steel, ferritic stainless steel ingot excellent in workability and toughness, and method for producing the same |
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