JP2008261007A - Ferritic stainless steel having excellent corrosion resistance in the existence of chlorine-based bleaching agent - Google Patents
Ferritic stainless steel having excellent corrosion resistance in the existence of chlorine-based bleaching agent Download PDFInfo
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本発明は、厨房などにおいて塩素系漂白剤のような腐食性物質に曝される環境下で使用される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 excellent in corrosion resistance used in an environment exposed to a corrosive substance such as a chlorine bleach in a kitchen or the like.
フェライト系ステンレス鋼は、その優れた耐食性から、主に大気腐食環境下で使用される自動車部品や建材などに広く使用されている。その耐食性向上機構は、大きく別けて２種類ある。ひとつは、Ｃｒの増加やＭｏの添加などに代表される、耐食性を向上させる元素を添加する方法である。例えば、特許文献１に開示されているＣｕを含有するフェライト系ステンレス鋼がその適用例の１つであり、自動車のモール材などに使用されている。 Ferritic stainless steel is widely used for automobile parts and building materials that are mainly used in an atmospheric corrosive environment because of its excellent corrosion resistance. There are two types of mechanisms for improving the corrosion resistance. One is a method of adding an element that improves corrosion resistance, represented by an increase in Cr, addition of Mo, or the like. For example, a ferritic stainless steel containing Cu disclosed in Patent Document 1 is one of its application examples, and is used for molding materials for automobiles.
もう一つは、Ｔｉなどの添加により非金属介在物を制御し、耐食性を向上させる方法である。例えば、特許文献２には、Ｔｉ添加量と熱間圧延前の加熱温度を適正な関係に制御することにより、大気環境中で良好な耐食性を示すフェライト系ステンレス鋼の製造方法が開示されている。
しかしながら、従来からあるステンレス鋼の多くは、大気環境下での使用を想定して開発されたものであり、厨房器具など、塩素系漂白剤のような腐食性物質にさらされる環境下で用いられた場合には、必ずしも良好な耐食性を示すとは限らない。そのため、斯かる特殊な腐食環境下で使用される材料は、その腐食環境に合わせて耐食性を改善し、発銹を防止する必要がある。 However, many of the conventional stainless steels were developed for use in an atmospheric environment and are used in environments exposed to corrosive substances such as kitchen bleaching agents such as kitchen appliances. In such a case, good corrosion resistance is not always exhibited. Therefore, the material used in such a special corrosive environment needs to improve the corrosion resistance in accordance with the corrosive environment and prevent the occurrence of cracking.
そこで、本発明の目的は、塩素系漂白剤存在下で問題となっている変色や発銹に対して優れた抑制効果のあるフェライト系ステンレス鋼を提供することにある。 Accordingly, an object of the present invention is to provide a ferritic stainless steel having an excellent inhibitory effect on discoloration and wrinkles which are problematic in the presence of a chlorine bleach.
発明者らは、フェライト系ステンレス鋼の塩素系漂白剤存在下での耐食性を向上するため、発銹起点となる非金属介在物に着目し、腐食部位を詳細に調査した。その結果、粗大なＴｉ４Ｃ２Ｓ２が発銹の起点として作用していていること、そして、この発銹起点となるＴｉ４Ｃ２Ｓ２を制御する、即ち、Ｔｉ，Ｓの添加量を適正範囲に制御するとともに、製造条件を適正化し、Ｓを微細なＴｉＳとして析出させることによって、耐食性を向上することができること、さらに、このステンレス鋼に、適正量のＣｕを加えと、耐食性がより向上すること、そして、これらの効果により塩素系漂白剤存在下でも変色や発銹を抑制できる耐食性を有するフェライト系ステンレス鋼を得ることができることを見出し、本発明を開発するに至った。 In order to improve the corrosion resistance of ferritic stainless steel in the presence of a chlorine-based bleach, the inventors focused on non-metallic inclusions as starting points for the corrosion and investigated the corrosion sites in detail. As a result, coarse Ti 4 C 2 S 2 acts as a starting point of the starting point, and Ti 4 C 2 S 2 that becomes the starting point of the starting point is controlled, that is, the amount of addition of Ti and S The corrosion resistance can be improved by optimizing the production conditions, optimizing the production conditions, and precipitating S as fine TiS. Furthermore, adding an appropriate amount of Cu to this stainless steel can improve the corrosion resistance. It has been found that a ferritic stainless steel having corrosion resistance capable of suppressing discoloration and wrinkling even in the presence of a chlorine bleaching agent can be obtained by these effects, and the present invention has been developed.
すなわち、本発明は、Ｃ：０．０２ｍａｓｓ％以下、Ｓｉ：０．０５〜１．０ｍａｓｓ％、Ｍｎ：０．３ｍａｓｓ％以下、Ｐ：０．０４ｍａｓｓ％以下、Ｓ：０．０１０ｍａｓｓ％以下、Ａｌ：０．１ｍａｓｓ％以下、Ｃｒ：２０．５〜２４．０ｍａｓｓ％、Ｃｕ：０．３〜０．８ｍａｓｓ％、Ｎｉ：１．０ｍａｓｓ％以下、Ｔｉ：０．２〜０．３ｍａｓｓ％、Ｎ：０．０２ｍａｓｓ％以下を含有し、Ｔｉ４Ｃ２Ｓ２としてのＳ量が０．００５ｍａｓｓ％以下であることを特徴とする塩素系漂白剤存在下での耐食性に優れるフェライト系ステンレス鋼である。 That is, the present invention includes C: 0.02 mass% or less, Si: 0.05 to 1.0 mass%, Mn: 0.3 mass% or less, P: 0.04 mass% or less, S: 0.010 mass% or less, Al : 0.1 mass% or less, Cr: 20.5 to 24.0 mass%, Cu: 0.3 to 0.8 mass%, Ni: 1.0 mass% or less, Ti: 0.2 to 0.3 mass%, N: It is a ferritic stainless steel excellent in corrosion resistance in the presence of a chlorine bleach, characterized by containing 0.02 mass% or less and the amount of S as Ti 4 C 2 S 2 is 0.005 mass% or less.
本発明によれば、塩素系漂白剤存在下での耐食性に優れたフェライト系ステンレス鋼を安定して得ることができる。 According to the present invention, a ferritic stainless steel excellent in corrosion resistance in the presence of a chlorine bleach can be stably obtained.
本発明のフェライト系ステンレス鋼が有すべき成分組成について説明する。
Ｃ：０．０２ｍａｓｓ％以下
Ｃは、鋼中に不可避的に混入する不純物元素であるが、０．０２ｍａｓｓ％を超えるとプレス加工性が低下するともに、Ｔｉ４Ｃ２Ｓ２の生成を促進して、塩素系漂白剤存在下での耐食性を低下させる。よって、Ｃは少ないほど好ましく、０．０２ｍａｓｓ％以下とする。好ましくは０．０１５ｍａｓｓ％以下である。
The component composition that the ferritic stainless steel of the present invention should have will be described.
C: 0.02 mass% or less C is an impurity element inevitably mixed in the steel, but if it exceeds 0.02 mass%, the press workability is lowered and the generation of Ti 4 C 2 S 2 is promoted. Thus, the corrosion resistance in the presence of chlorine bleach is reduced. Therefore, the smaller C is, the more preferable, and 0.02 mass% or less. Preferably it is 0.015 mass% or less.
Ｎ：０．０２ｍａｓｓ％以下
Ｎは、鋼中に固溶すると、耐食性を向上させる効果がある。しかし、０．０２ｍａｓｓ％を超えて添加すると、プレス加工性が低下する。よって、Ｎ含有量は０．０２ｍａｓｓ％以下とする。好ましくは０．０１５ｍａｓｓ％以下である。
N: 0.02 mass% or less N, when dissolved in steel, has an effect of improving corrosion resistance. However, when it exceeds 0.02 mass%, press workability will fall. Therefore, N content shall be 0.02 mass% or less. Preferably it is 0.015 mass% or less.
Ｓｉ：０．０５〜１．０ｍａｓｓ％
Ｓｉは、脱酸剤として添加される有用な元素であり、含有量が０．０５ｍａｓｓ％未満では、十分な脱酸効果が得られず、酸化物が多量に鋼中に分散してプレス加工性が劣化する。一方、１．０ｍａｓｓ％超え添加すると、鋼が硬質化して機械的性質の劣化を招く。よって、Ｓｉは０．０５〜１．０ｍａｓｓ％の範囲とする。
Si: 0.05 to 1.0 mass%
Si is a useful element added as a deoxidizer. If the content is less than 0.05 mass%, a sufficient deoxidation effect cannot be obtained, and a large amount of oxide is dispersed in the steel, so that press workability is achieved. Deteriorates. On the other hand, if added over 1.0 mass%, the steel becomes hard and mechanical properties are deteriorated. Therefore, Si is set to a range of 0.05 to 1.0 mass%.
Ｍｎ：０．３ｍａｓｓ％以下
Ｍｎは、脱酸作用があるが、過剰な添加は固溶強化により加工性を損なう上、ＭｎＳとして析出して耐食性を低下するので、含有量は低いほうが望ましい。よって、Ｍｎの含有量は０．３ｍａｓｓ％以下とする。
Mn: 0.3 mass% or less Although Mn has a deoxidizing action, excessive addition impairs workability due to solid solution strengthening and also precipitates as MnS to lower the corrosion resistance. Therefore, the lower content is desirable. Therefore, the Mn content is set to 0.3 mass% or less.
Ｐ：０．０４ｍａｓｓ％以下
Ｐは、耐食性および熱間加工性を劣化させるため、表面性状が劣化する。よって、Ｓ含有量は低いほうが望ましく、０．０４ｍａｓｓ％以下とする。好ましくは０．０３ｍａｓｓ％以下である。
P: 0.04 mass% or less Since P deteriorates corrosion resistance and hot workability, surface properties deteriorate. Therefore, it is desirable that the S content is low, and it is set to 0.04 mass% or less. Preferably it is 0.03 mass% or less.
Ｓ：０．０１０ｍａｓｓ％以下
Ｓは、本発明において、重要な成分の一つである。ステンレス鋼中のＳは、Ｍｎと非金属介在物ＭｎＳを作り、大気中の水分と反応してｐＨを低下させ、発銹の原因となることが従来から知られている。そのため、ＭｎよりもＳと結合しやすいＴｉを添加し、ＳをＴｉ系の非金属介在物として無害化する方法がとられてきた。ＴｉとＳの非金属介在物には、Ｔｉ４Ｃ２Ｓ２とＴｉＳとが知られており、このうちＴｉ４Ｃ２Ｓ２は粗大な介在物となりやすい。塩素系漂白剤存在下で腐食させると、発銹点に粗大なＴｉ４Ｃ２Ｓ２が存在している個所が多く確認されたことから、Ｔｉ４Ｃ２Ｓ２から発銹が起こっているものと考えられる。逆に、微細に分散したＴｉＳの周囲には、非金属介在物を起点とする腐食は観察されなかった。Ｔｉ４Ｃ２Ｓ２は、Ｓ含有量が０．０１０ｍａｓｓ％を超えると、生成が促進されて粗大化するので、Ｓは０．０１０ｍａｓｓ％以下とする必要がある。好ましくは、０．００５ｍａｓｓ％以下である。
S: 0.010 mass% or less S is one of the important components in the present invention. It has been conventionally known that S in stainless steel forms Mn and non-metallic inclusions MnS, reacts with moisture in the air, lowers pH, and causes rusting. For this reason, a method has been used in which Ti, which is easier to bond to S than Mn, is added to detoxify S as a Ti-based nonmetallic inclusion. Ti 4 C 2 S 2 and TiS are known as nonmetallic inclusions of Ti and S. Of these, Ti 4 C 2 S 2 tends to be coarse inclusions. When corrosive in the presence of a chlorine bleach, there are many places where coarse Ti 4 C 2 S 2 is present at the starting point, and thus, starting from Ti 4 C 2 S 2 has occurred. It is considered a thing. On the contrary, no corrosion starting from non-metallic inclusions was observed around the finely dispersed TiS. When the S content exceeds 0.010 mass%, Ti 4 C 2 S 2 is promoted and coarsened, so S needs to be 0.010 mass% or less. Preferably, it is 0.005 mass% or less.
上記Ｔｉ４Ｃ２Ｓ２が発銹の原因となる理由については、いまだ充分には解明されていないが、以下のように推測している。Ｔｉ４Ｃ２Ｓ２の大きな析出物が鋼表面に形成されると、Ｔｉ４Ｃ２Ｓ２と地鉄との間に隙間状の微小な凹凸ができ、この凹凸内部は平滑な表面に比べて拡散が遅くイオンの蓄積が起こりやすい。その結果、塩素系漂白剤によってＴｉ４Ｃ２Ｓ２が僅かに溶解して水と反応し、水素イオンが生成し、生成した水素イオンは凹凸内に蓄積しｐＨを低下させる。一方、水素イオンと対をなす陰イオンが不足するため、凹凸の内部と平滑な表面との間で電位差が生じ、腐食の起こりやすい環境となる。加えて、粗大な非金属介在物の周囲は、ステンレス鋼の不動態皮膜で表面を完全に覆うことができないので、わずかなｐＨの低下によって、容易に活性態へ移行し、腐食が進行する。こういった要因から、粗大なＴｉ４Ｃ２Ｓ２が発銹起点となると考えられる。 The reason why the above Ti 4 C 2 S 2 causes rusting has not yet been fully elucidated, but is presumed as follows. When a large precipitate of Ti 4 C 2 S 2 is formed on the steel surface, there are minute gaps between the Ti 4 C 2 S 2 and the ground iron. Therefore, diffusion is slow and ion accumulation tends to occur. As a result, Ti 4 C 2 S 2 is slightly dissolved by the chlorine bleach and reacts with water to generate hydrogen ions, and the generated hydrogen ions accumulate in the unevenness and lower the pH. On the other hand, since the anion paired with the hydrogen ion is insufficient, a potential difference is generated between the inside of the unevenness and the smooth surface, and an environment in which corrosion easily occurs is obtained. In addition, since the surface of coarse non-metallic inclusions cannot be completely covered with a stainless steel passive film, a slight decrease in pH easily shifts to an active state and progresses corrosion. From these factors, it is considered that coarse Ti 4 C 2 S 2 is the starting point.
Ａｌ：０．１ｍａｓｓ％以下
Ａｌは、脱酸のために添加される成分であるが、０．１ｍａｓｓ％を超えると、Ａｌ系の非金属介在物の増加により表面疵の発生を招くとともに、加工性も低下させる。よって、Ａｌは０．１ｍａｓｓ％以下とする。
Al: 0.1 mass% or less Al is a component added for deoxidation. However, if it exceeds 0.1 mass%, an increase in Al-based non-metallic inclusions leads to generation of surface defects and processing. It also reduces the nature. Therefore, Al is 0.1 mass% or less.
Ｃｒ：２０．５〜２４．０ｍａｓｓ％
Ｃｒは、フェライト系ステンレス鋼としての耐食性を決定する重要な元素であり、そのためには２０．５ｍａｓｓ％以上添加する必要がある。そして、Ｃｒは、含有量が高いほど耐食性を向上するが、２４．０ｍａｓｓ％を超えて添加すると、σ相を生成しやすくなり、プレス加工性が低下する。よって、Ｃｒの含有量は２０．５〜２４．０ｍａｓｓ％の範囲とする。好ましくは、２１．０〜２３．０ｍａｓｓ％の範囲である。
Cr: 20.5 to 24.0 mass%
Cr is an important element that determines the corrosion resistance of the ferritic stainless steel, and for that purpose it is necessary to add 20.5 mass% or more. And although Cr improves corrosion resistance, so that content is high, when it adds exceeding 24.0 mass%, it will become easy to produce | generate a (sigma) phase and press workability will fall. Therefore, the Cr content is in the range of 20.5 to 24.0 mass%. Preferably, it is the range of 21.0-23.0 mass%.
Ｃｕ：０．３〜０．８ｍａｓｓ％
Ｃｕは、本発明において、主要な成分の一つである。腐食発生後、ステンレス鋼の表面に皮膜を形成し、アノード反応による地鉄の溶解を低減する効果がある。また、耐発銹性の向上にも有効であるが、特に耐隙間腐食性の向上に有効な元素である。さらに、発明者らは、Ｃｕを添加することで、微細なＴｉＳの周囲の不動態皮膜が改質され、耐食性がより向上することを新規に見出した。これらの効果は、０．３ｍａｓｓ％以上の添加で発現する。しかし、０．８ｍａｓｓ％を超えるＣｕの過剰な添加は、Ｃｕ自身の溶解を促進し、却って耐食性を低下させる。よって、Ｃｕは０．３〜０．８ｍａｓｓ％の範囲とする。好ましくは、０．４〜０．６ｍａｓｓ％の範囲である。
Cu: 0.3 to 0.8 mass%
Cu is one of the main components in the present invention. After corrosion occurs, a film is formed on the surface of the stainless steel, and there is an effect of reducing dissolution of the ground iron due to the anode reaction. Further, it is effective for improving the rust resistance, but is an element particularly effective for improving the crevice corrosion resistance. Furthermore, the inventors have newly found that by adding Cu, the passive film around the fine TiS is modified and the corrosion resistance is further improved. These effects are manifested by addition of 0.3 mass% or more. However, excessive addition of Cu exceeding 0.8 mass% promotes dissolution of Cu itself, and on the contrary, reduces corrosion resistance. Therefore, Cu is set to a range of 0.3 to 0.8 mass%. Preferably, it is the range of 0.4-0.6 mass%.
なお、ＣｕがＴｉＳの周囲の不動態皮膜を改質する理由については十分に明らかになっていないが、ＴｉＳの周囲に存在するＣｕは、Ｆｅの結晶格子に歪みを生じさせ、歪みが生じた結晶格子上に生成される不動態皮膜は、通常の結晶格子上に生成される不動態皮膜に比べて、アモルファス状に緻密化し、酸素や塩素イオンなどの腐食に関わる物質の透過を抑制する作用が高まり、その結果、耐食性が向上して発銹が抑制されるものと考えられる。 The reason why Cu modifies the passive film around TiS has not been fully clarified, but Cu existing around TiS causes distortion in the Fe crystal lattice, resulting in distortion. The passive film formed on the crystal lattice is densified into an amorphous state and suppresses the transmission of substances related to corrosion such as oxygen and chlorine ions, compared to the passive film formed on the normal crystal lattice. As a result, it is considered that the corrosion resistance is improved and the wrinkle is suppressed.
Ｎｉ：１．０ｍａｓｓ％以下
Ｎｉは、耐食性を向上する効果があるが、１．０ｍａｓｓ％を超えて添加すると、鋼を硬質化する。よって、Ｎｉは１．０ｍａｓｓ％以下とする。
Ni: 1.0 mass% or less Ni has an effect of improving the corrosion resistance, but if added exceeding 1.0 mass%, the steel is hardened. Therefore, Ni is set to 1.0 mass% or less.
Ｔｉ：０．２〜０．３ｍａｓｓ％
Ｔｉは、本発明において重要な成分の一つであり、Ｓを固定して、ＭｎＳの生成による耐発銹性の低下を防ぐとともに、Ｃ，Ｎを固定してＣｒ炭窒化物形成による鋭敏化を抑制する効果がある。上記鋭敏化防止効果は、０．２ｍａｓｓ％以下のＴｉ添加では十分な効果が得られない。さらに、Ｔｉは、前述したように、Ｃｕの添加されたフェライト系ステンレス鋼において、ＳをＴｉＳとして微細に析出させることで耐食性を向上させる効果がある。しかし、Ｔｉの０．３ｍａｓｓ％を超える添加は、加工性を低下させるとともに、Ｔｉ４Ｃ２Ｓ２の析出を促進し、塩素系漂白剤存在下での耐食性を低下させる。よって、Ｔｉは０．２〜０．３ｍａｓｓ％の範囲とする。好ましくは、０．２６〜０．２９ｍａｓｓ％の範囲である。
Ti: 0.2-0.3 mass%
Ti is one of the important components in the present invention. S is fixed to prevent deterioration of rust resistance due to the formation of MnS, and C and N are fixed and sensitization by Cr carbonitride formation. There is an effect to suppress. The effect of preventing sensitization cannot be obtained sufficiently by adding Ti of 0.2 mass% or less. Furthermore, Ti has the effect of improving corrosion resistance by finely precipitating S as TiS in the ferritic stainless steel to which Cu is added, as described above. However, the addition of Ti exceeding 0.3 mass% reduces workability, promotes precipitation of Ti 4 C 2 S 2 , and reduces corrosion resistance in the presence of a chlorine bleach. Therefore, Ti is set to a range of 0.2 to 0.3 mass%. Preferably, it is the range of 0.26-0.29 mass%.
Ｔｉ４Ｃ２Ｓ２としてのＳ量：０．００５ｍａｓｓ％以下
前述したように、粗大なＴｉ４Ｃ２Ｓ２が生成されると、塩素系漂白剤の存在下では、これを起点として発銹する。そこで、発銹とＴｉ４Ｃ２Ｓ２となるＳ量の相関について調査したところ、Ｔｉ４Ｃ２Ｓ２となるＳ量が０．００５ｍａｓｓ％以下ならば、生成したＴｉ４Ｃ２Ｓ２も比較的小さく、発銹起点となりにくいことが明らかとなった。よって、Ｔｉ４Ｃ２Ｓ２となるＳ量は０．００５ｍａｓｓ％以下とする。
S amount as Ti 4 C 2 S 2 : 0.005 mass% or less As described above, when coarse Ti 4 C 2 S 2 is produced, it is generated from the origin in the presence of a chlorine bleach. To do. Therefore, were investigated correlation S amount to be rusted and Ti 4 C 2 S 2, if the S content to be Ti 4 C 2 S 2 is less 0.005 mass%, also generated Ti 4 C 2 S 2 It was found that it was relatively small and difficult to become a starting point. Therefore, the amount of S that becomes Ti 4 C 2 S 2 is set to 0.005 mass% or less.
上記成分以外の残部は、Ｆｅおよび不可避的不純物である。なお、不純物としては、Ｎｂ，Ｂ，Ｃa，Ｓｎ，Ｖなどの元素が混入することがあるが、加工性および耐食性の観点からは、これら元素の混入量は少ない方がよく、好ましくは、Ｎｂ：０．１ｍａｓｓ％以下、Ｂ：０．００５ｍａｓｓ％以下、Ｃa：０．０１ｍａｓｓ％以下、Ｓｎ：０．１ｍａｓｓ％以下、Ｖ：０．１ｍａｓｓ％以下である。 The balance other than the above components is Fe and inevitable impurities. As impurities, elements such as Nb, B, Ca, Sn, and V may be mixed. From the viewpoint of workability and corrosion resistance, the amount of these elements mixed is preferably small, and preferably Nb. : 0.1 mass% or less, B: 0.005 mass% or less, Ca: 0.01 mass% or less, Sn: 0.1 mass% or less, V: 0.1 mass% or less.
次に、本発明に係るフェライト系ステンレス鋼の好ましい製造方法について説明する。本発明のステンレス鋼は、例えば、上述した適正な成分組成を有する鋼スラブを、１１５０℃〜１２００℃に加熱後、仕上圧延終了温度を７００℃〜９００℃とする熱間圧延を施して板厚２．５〜５ｍｍとし、５００℃以下で巻き取り、熱間圧延鋼帯とするのが好ましい。この際、仕上圧延後の冷却は、通常の冷却速度では、ＴｉＳの一部がＴｉ４Ｃ２Ｓ２に変化するため、２０℃／Ｓ以上の冷却速度で５００℃以下まで冷却するのが好ましい。また、巻き取り後の冷却は、４７５℃付近に滞留すると、いわゆる４７５℃脆性による靭性の低下が起こるため、５５０〜４００℃の温度範囲の冷却速度は１００℃／ｈｒ以上とするのが好ましい。上記のようにして得た熱間圧延鋼帯は、その後、８００〜１０００℃の温度で熱延板焼鈍し、酸洗し、冷間圧延し、次いで、冷延板焼鈍と酸洗を行い冷延焼鈍板（製品）とするのが好ましい。なお、焼鈍中においては、Ｔｉ４Ｃ２Ｓ２の生成が起こるので、８００℃以上となる時間は１分以下とすることが望ましい。その他の条件については、特に制限はない。 Next, the preferable manufacturing method of the ferritic stainless steel which concerns on this invention is demonstrated. The stainless steel of the present invention is obtained by, for example, heating a steel slab having the above-described proper component composition to 1150 ° C. to 1200 ° C., and then subjecting the steel slab to a finish rolling finishing temperature of 700 ° C. to 900 ° C. It is preferable to set it as 2.5-5 mm, wind up at 500 degrees C or less, and make it a hot rolled steel strip. At this time, cooling after finish rolling is preferably performed at a cooling rate of 20 ° C./S or higher to 500 ° C. or lower because a part of TiS changes to Ti 4 C 2 S 2 at a normal cooling rate. . Further, since cooling after winding takes place at around 475 ° C., so-called 475 ° C. brittleness causes a decrease in toughness. Therefore, the cooling rate in the temperature range of 550 to 400 ° C. is preferably 100 ° C./hr or more. The hot-rolled steel strip obtained as described above is subsequently subjected to hot-rolled sheet annealing at a temperature of 800 to 1000 ° C., pickled, cold-rolled, and then cold-rolled sheet annealed and pickled. It is preferable to use a fire-annealed plate (product). Incidentally, during the annealing, since the generation of Ti 4 C 2 S 2 occurs, the time to be 800 ° C. or higher is preferably less than or equal to 1 minute. Other conditions are not particularly limited.
表１に示した成分組成を有するＮｏ．１〜２０のフェライト系ステンレス鋼を溶製して鋼塊とした後、これらの鋼塊を１１７０℃の温度に加熱してから仕上温度を８００℃、巻き取り温度を４５０℃とする熱間圧延を行い、板厚４ｍｍの熱延板とした。その後、７００〜９５０℃の温度で焼鈍し、酸洗し、冷間圧延して、板厚０．８ｍｍの冷延板とし、次いで、８８０℃で仕上焼鈍して冷延焼鈍板（製品）とした。 No. having the component composition shown in Table 1. After melting 1-20 ferritic stainless steels into steel ingots, these steel ingots are heated to a temperature of 1170 ° C. and then finished at a finish temperature of 800 ° C. and a coiling temperature of 450 ° C. To obtain a hot-rolled sheet having a thickness of 4 mm. Thereafter, annealing is performed at a temperature of 700 to 950 ° C., pickling, cold rolling to obtain a cold-rolled sheet having a thickness of 0.8 mm, and then finish annealing at 880 ° C. to obtain a cold-rolled annealed sheet (product) did.
上記のようにして得た冷延焼鈍板を６００番のエメリー紙で研磨したのち、張り出し加工により、深さ５ｍｍの円形のくぼみを有する形状に加工した。このくぼみに、台所用漂白剤の原液（キッチンハイター；花王株式会社製）を１ｍｌ滴下して、３５℃、相対湿度ＲＨ９０％の環境に２４時間おき、試験後、くぼみ内部を観察し、変色または孔食が確認されたものを不合格（×）と評価した。結果を表１に併記して示した。 The cold-rolled annealed plate obtained as described above was polished with No. 600 emery paper, and then processed into a shape having a circular recess having a depth of 5 mm by overhanging. 1 ml of a stock solution of kitchen bleach (Kitchen Hiter; manufactured by Kao Co., Ltd.) is dropped into this pit and left in an environment of 35 ° C. and relative humidity RH 90% for 24 hours. Those in which pitting corrosion was confirmed were evaluated as rejected (x). The results are shown together in Table 1.
試験後の試験片について、ＴＥＭを用いて、Ｔｉ４Ｃ２Ｓ２、ＴｉＳの析出状態を観察した。その結果、腐食の発生した試験片では、大きさが２００ｎｍ以上の粗大なＴｉ４Ｃ２Ｓ２が多く観察され、また、ＴｉＳの多くは、その周辺部にＴｉ４Ｃ２Ｓ２が付着して複合型の粗大な析出物となっていた。逆に、腐食の発生しなかった試験片では、Ｔｉ４Ｃ２Ｓ２の数も少なく、大きさも小さかった。その代わり、５０ｎｍほどのサイズの微細なＴｉＳが多数、分散析出していることが確認された。 The test piece after the test, using TEM, the observed precipitation state of Ti 4 C 2 S 2, TiS . As a result, a large amount of coarse Ti 4 C 2 S 2 having a size of 200 nm or more is observed in the test piece in which corrosion occurs, and most of TiS has Ti 4 C 2 S 2 attached to the periphery thereof. As a result, a composite type coarse precipitate was formed. On the contrary, in the test piece in which corrosion did not occur, the number of Ti 4 C 2 S 2 was small and the size was small. Instead, it was confirmed that a large amount of fine TiS having a size of about 50 nm was dispersed and precipitated.
本発明によれば、厨房等の塩素系漂白剤にさらされる環境においても発銹の起こりにくいフェライト系ステンレス鋼が得られる。 ADVANTAGE OF THE INVENTION According to this invention, the ferritic stainless steel which does not generate | occur | produce easily in an environment exposed to chlorine-type bleaching agents, such as a kitchen, is obtained.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014087648A1 (en) * | 2012-12-07 | 2014-06-12 | Ｊｆｅスチール株式会社 | Ferritic stainless steel sheet |
| WO2014142302A1 (en) * | 2013-03-14 | 2014-09-18 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56146859A (en) * | 1980-04-18 | 1981-11-14 | Nisshin Steel Co Ltd | Ferritic stainless steel with resistance to environment containing chlorine ion |
| JPH07180001A (en) * | 1993-12-22 | 1995-07-18 | Nippon Steel Corp | Ferritic stainless steel bright annealing material excellent in workability and rust resistance |
| JP2004002974A (en) * | 2002-03-27 | 2004-01-08 | Nippon Steel Corp | Cast slab and steel sheet of ferritic stainless steel and production method for the same |
| JP2004323907A (en) * | 2003-04-24 | 2004-11-18 | Nippon Steel Corp | Ferritic stainless steel for automobile exhaust system member having excellent initial rust resistance |
| JP2007077496A (en) * | 2005-08-17 | 2007-03-29 | Jfe Steel Kk | Ferritic stainless-steel sheet with excellent corrosion resistance and process for producing the same |
| JP2007092163A (en) * | 2005-09-02 | 2007-04-12 | Nisshin Steel Co Ltd | Automobile exhaust gas flow passage member |
| JP2008001945A (en) * | 2006-06-22 | 2008-01-10 | Nippon Steel & Sumikin Stainless Steel Corp | Bright annealing-finished ferritic stainless steel sheet having excellent rusting resistance and workability and method for producing the same |
-
2007
- 2007-04-12 JP JP2007104532A patent/JP5151222B2/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56146859A (en) * | 1980-04-18 | 1981-11-14 | Nisshin Steel Co Ltd | Ferritic stainless steel with resistance to environment containing chlorine ion |
| JPH07180001A (en) * | 1993-12-22 | 1995-07-18 | Nippon Steel Corp | Ferritic stainless steel bright annealing material excellent in workability and rust resistance |
| JP2004002974A (en) * | 2002-03-27 | 2004-01-08 | Nippon Steel Corp | Cast slab and steel sheet of ferritic stainless steel and production method for the same |
| JP2004323907A (en) * | 2003-04-24 | 2004-11-18 | Nippon Steel Corp | Ferritic stainless steel for automobile exhaust system member having excellent initial rust resistance |
| JP2007077496A (en) * | 2005-08-17 | 2007-03-29 | Jfe Steel Kk | Ferritic stainless-steel sheet with excellent corrosion resistance and process for producing the same |
| JP2007092163A (en) * | 2005-09-02 | 2007-04-12 | Nisshin Steel Co Ltd | Automobile exhaust gas flow passage member |
| JP2008001945A (en) * | 2006-06-22 | 2008-01-10 | Nippon Steel & Sumikin Stainless Steel Corp | Bright annealing-finished ferritic stainless steel sheet having excellent rusting resistance and workability and method for producing the same |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014087648A1 (en) * | 2012-12-07 | 2014-06-12 | Ｊｆｅスチール株式会社 | Ferritic stainless steel sheet |
| JP5664826B2 (en) * | 2012-12-07 | 2015-02-04 | Ｊｆｅスチール株式会社 | Ferritic stainless steel sheet |
| CN104685089A (en) * | 2012-12-07 | 2015-06-03 | 杰富意钢铁株式会社 | Jfe steel corporation |
| WO2014142302A1 (en) * | 2013-03-14 | 2014-09-18 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same |
| KR20150110816A (en) * | 2013-03-14 | 2015-10-02 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same |
| CN105008571A (en) * | 2013-03-14 | 2015-10-28 | 新日铁住金不锈钢株式会社 | Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same |
| KR101688760B1 (en) | 2013-03-14 | 2016-12-21 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same |
| JPWO2014142302A1 (en) * | 2013-03-14 | 2017-02-16 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet with small increase in strength after aging heat treatment and manufacturing method thereof |
| US10513747B2 (en) | 2013-03-14 | 2019-12-24 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic stainless steel sheet exhibiting small increase in strength after aging heat treatment, and method of producing the same |
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