JP4119941B2 - Marine steel with excellent crevice corrosion resistance in humid air - Google Patents

Marine steel with excellent crevice corrosion resistance in humid air Download PDF

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JP4119941B2
JP4119941B2 JP2007240067A JP2007240067A JP4119941B2 JP 4119941 B2 JP4119941 B2 JP 4119941B2 JP 2007240067 A JP2007240067 A JP 2007240067A JP 2007240067 A JP2007240067 A JP 2007240067A JP 4119941 B2 JP4119941 B2 JP 4119941B2
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JP2008007860A (en
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真司 阪下
文雄 湯瀬
淳 久本
誠一 大垣
重雄 岡野
洋一郎 小林
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Kobe Steel Ltd
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本発明は、原油タンカー、貨物船、貨客船、客船、軍艦等の船舶において、主要な構造材として用いられる船舶用耐食鋼に関するものであり、特に湿潤の大気雰囲気での耐すきま腐食性に優れた船舶用鋼材に関するものである。   The present invention relates to marine corrosion resistant steel used as a main structural material in ships such as crude oil tankers, cargo ships, cargo passenger ships, passenger ships, warships and the like, and is particularly excellent in crevice corrosion resistance in a humid atmospheric atmosphere. It relates to marine steel.

上記各種船舶において主要な構造材(例えば、外板、バラストタンク、原油タンク等)として用いられている鋼材は、海水による塩分や高温多湿に曝されることから腐食損傷を受けることが多い。こうした腐食は、浸水や沈没などの海難事故を招く恐れがあることから、鋼材には何らかの防食手段を施す必要がある。これまで行われている防食手段としては、(a)塗装や(b)電気防食等が従来からよく知られている。   Steel materials used as main structural materials (for example, outer plates, ballast tanks, crude oil tanks, etc.) in the above various ships are often corroded because they are exposed to salt from seawater and high temperature and humidity. Since such corrosion may cause marine accidents such as inundation and sinking, it is necessary to apply some anticorrosion means to the steel. Conventionally, (a) coating, (b) cathodic protection, and the like are well known as anticorrosion means used so far.

このうち重塗装に代表される塗装では、塗膜欠陥が存在する可能性が高く、製造工程における衝突等によって塗膜に傷が付く場合もあるため、素地鋼材が露出してしまうことが多い。このような鋼材露出部においては、局部的にかつ集中的に鋼材が腐食してしまい、収容されている石油系液体燃料の早期漏洩に繋がることになる。   Of these, in coatings represented by heavy coating, there is a high possibility that coating film defects exist, and the coating film may be damaged due to a collision or the like in the manufacturing process, so that the base steel material is often exposed. In such a steel exposed portion, the steel material corrodes locally and intensively, leading to early leakage of the petroleum-based liquid fuel contained therein.

一方、電気防食においては、海水中に完全に浸漬された部位に対しては、非常に有効であるが、大気中で海水飛沫を受ける部位などでは防食に必要な電気回路が形成されず、防食効果が十分に発揮されないことがある。また、防食用の流電陽極が異常消耗や脱落して消失した場合には、直ちに激しい腐食が進行することがある。   On the other hand, in the anti-corrosion, it is very effective for the part completely immersed in the seawater. However, in the part that receives the seawater splash in the atmosphere, the electric circuit necessary for the anticorrosion is not formed, and the anticorrosion. The effect may not be fully demonstrated. In addition, when the galvanic anode for anticorrosion disappears due to abnormal consumption or dropping, severe corrosion may immediately proceed.

上記技術の他、鋼材自体の耐食性を向上させるものとして例えば特許文献1のような技術も提案されている。この技術では、鋼材の化学成分を適切に調整することによって、耐食性を優れたものとし、無塗装であっても使用できる造船用耐食鋼が開示されている。また特許文献2には、鋼材の化学成分組成を適切なものとすることによって、塗膜寿命性を向上させた船舶用鋼材について開示されている。これらの技術では、従来に比べてある程度の耐食性は確保できるようになったといえる。   In addition to the above technique, for example, a technique as disclosed in Patent Document 1 has been proposed as a means for improving the corrosion resistance of the steel material itself. This technology discloses a corrosion-resistant steel for shipbuilding that has excellent corrosion resistance by appropriately adjusting the chemical composition of the steel material and can be used even without coating. Patent Document 2 discloses a marine steel material having an improved coating film life by making the chemical composition of the steel material appropriate. With these technologies, it can be said that a certain degree of corrosion resistance can be ensured as compared with the prior art.

しかしながら、より厳しい腐食環境下での耐食性については依然として十分なものとはいえず、更なる耐食性向上が要求されることになる。特に、異物と鋼材との接触部分、構造的な理由や防食塗膜の損傷部分等で形成される「すきま」部分における腐食(いわゆるすきま腐食)が顕著になり、寿命を低下させる場合があるが、これまで提案されている技術ではこうした部分における耐食性が不十分である。
特開2000−17381号公報 特許請求の範囲等 特開2002−266052号公報 特許請求の範囲等
However, the corrosion resistance in a more severe corrosive environment is still not sufficient, and further improvement in corrosion resistance is required. In particular, corrosion (so-called crevice corrosion) in the “clearance” portion formed at the contact portion between the foreign material and the steel material, the structural reason, or the damaged portion of the anticorrosion coating film, etc., becomes prominent and may reduce the service life. So far, the proposed techniques have insufficient corrosion resistance in these areas.
JP, 2000-17381, A Claims etc. JP, 2002-266052, A Claims etc.

本発明は上記の様な事情に着目してなされたものであって、その目的は、塗装や電気防食を施さなくても実用化できる耐食性に優れた船舶用鋼材、特に電気防食が作用しないバラストタンク内の上部や原油タンク上甲板等の湿潤の大気雰囲気において、すきま腐食などに対して優れた耐久性を発揮する船舶用鋼材を提供することにある。   The present invention has been made paying attention to the circumstances as described above, and its purpose is to provide a marine steel material excellent in corrosion resistance that can be put into practical use without being subjected to painting or anticorrosion, in particular, ballast that does not act on anticorrosion. An object of the present invention is to provide a marine steel material that exhibits excellent durability against crevice corrosion in a humid atmospheric atmosphere such as an upper part of a tank or an upper deck of a crude oil tank.

上記目的を達成することのできた本発明の船舶用鋼材とは、C:0.04〜0.18%(質量%の意味、以下同じ)、Si:0.10〜0.50%、Mn:0.10〜1.80%、Al:0.05〜0.50%、Cu:0.05〜4.00%、Cr:0.05〜4.50%を夫々含有する他、Ni:0.05〜5.0%、Co:0.01〜5.0%およびTi:0.008〜0.20%よりなる群から選ばれる2種以上を含有し、更にCa:0.0010〜0.015%および/またはMg:0.0005〜0.020%を含有し、P:0.020%以下(0%を含む)およびS:0.010%以下(0%を含む)に夫々抑制し、残部がFeおよび不可避的不純物からなり、且つCrの含有量[Cr]とAlの含有量[Al]の比の値([Cr]/[Al])が1〜50である点に要旨を有するものである。   The marine steel material of the present invention that has achieved the above object is C: 0.04 to 0.18% (meaning of mass%, the same shall apply hereinafter), Si: 0.10 to 0.50%, Mn: In addition to containing 0.10 to 1.80%, Al: 0.05 to 0.50%, Cu: 0.05 to 4.00%, Cr: 0.05 to 4.50%, Ni: 0 0.05% to 5.0%, Co: 0.01% to 5.0%, and Ti: 0.008% to 0.20% or more selected from the group consisting of Ca: 0.0010-0 .015% and / or Mg: 0.0005 to 0.020%, P: 0.020% or less (including 0%) and S: 0.010% or less (including 0%), respectively The balance is Fe and inevitable impurities, and the ratio of Cr content [Cr] to Al content [Al] ([Cr / [Al]) is one having the gist in that 1 to 50.

本発明の船舶用鋼材においては、必要によって、(1)Se:0.005〜0.50%、(2)Sb:0.01〜0.50%および/またはSn:0.01〜0.50%、(3)B:0.0001〜0.010%、V:0.01〜0.50%およびNb:0.003〜0.50%よりなる群から選ばれる1種以上、等を含有させることも有効であり、含有させる成分の種類に応じて船舶用鋼材の特性が更に改善されることになる。   In the marine steel material of the present invention, (1) Se: 0.005-0.50%, (2) Sb: 0.01-0.50% and / or Sn: 0.01-0. 50%, (3) one or more selected from the group consisting of B: 0.0001 to 0.010%, V: 0.01 to 0.50% and Nb: 0.003 to 0.50%, etc. It is also effective to contain it, and the characteristics of the marine steel will be further improved according to the kind of the component to be contained.

本発明の造船用鋼材においては、所定量のAlとCrを併用させて含有させると共に、化学成分組成を適切に調整することによって、塗装および電気防食を施さなくても実用化できる耐食性に優れた船舶用鋼が実現でき、特にすきま腐食に対する耐久性の向上を図ると共に、電気防食が作用しないバラストタンク内の上部や原油タンク上甲板等の湿潤の大気雰囲気において、すきま腐食などに対して優れた耐久性を発揮する船舶用鋼材が実現できた。こうした船舶用鋼材は、上記用途の他、原油タンカー、貨物船、貨客船、客船、軍艦等の船舶における外板等の素材として有用である。   In the steel material for shipbuilding of the present invention, a predetermined amount of Al and Cr are used together and contained, and by appropriately adjusting the chemical composition, it has excellent corrosion resistance that can be put into practical use without coating and cathodic protection. Ship steel can be realized, and in particular, the durability against crevice corrosion is improved, and it is excellent against crevice corrosion in wet air atmosphere such as the upper part of the ballast tank and the upper deck of the crude oil tank where no anticorrosion acts. A marine steel material that demonstrates durability was realized. In addition to the above-mentioned uses, such marine steel materials are useful as materials for outer plates and the like in ships such as crude oil tankers, cargo ships, cargo passenger ships, passenger ships, warships and the like.

本発明者らは、前記課題を解決するために鋭意研究を重ねた。その結果、所定量のAlとCrを併用させて含有させると共に、化学成分組成を適切に調整すれば、上記課題を解決することのできる船舶用鋼材が実現できることを見出し、本発明を完成した。   The inventors of the present invention have made extensive studies to solve the above problems. As a result, the present inventors have found that a marine steel material capable of solving the above-described problems can be realized if a predetermined amount of Al and Cr are contained in combination and the chemical composition is appropriately adjusted, thereby completing the present invention.

本発明の鋼材においては、AlとCrを併用させて含有させることが重要であり、これらの成分のいずれを欠いても、本発明の目的を達成することができない。これらの成分における各作用効果は後述するが、これらを併用することによって、耐食性が向上した理由は次のように考えることができた。   In the steel material of the present invention, it is important to contain Al and Cr in combination, and the object of the present invention cannot be achieved without any of these components. Although each effect of these components will be described later, the reason why the corrosion resistance is improved by using these components in combination can be considered as follows.

Alは鋼表面に安定な酸化物防食皮膜を形成する効果がある。鋼中より腐食溶解したAl3+イオンが溶存酸素などと結びついてAl酸化物となり、これが表面に堆積して防食皮膜を形成することになる。この皮膜による防食効果は、船舶における高塩化物環境においては十分とはいえない。一方、Crは上記Alと同様に表面に安定な酸化物皮膜を形成して鋼材を防食する効果を発揮するが、Cr酸化物単独ではその防食効果が十分であるとはいえない。 Al has the effect of forming a stable oxide anticorrosion film on the steel surface. Al 3+ ions corroded and dissolved in the steel are combined with dissolved oxygen or the like to form Al oxide, which is deposited on the surface to form an anticorrosion film. The anticorrosive effect of this film is not sufficient in a high chloride environment on ships. On the other hand, Cr, like Al, forms a stable oxide film on the surface and exhibits an effect of preventing corrosion of the steel material. However, Cr oxide alone cannot be said to have sufficient corrosion protection effect.

上記Al酸化皮膜は、pHが5〜8.5程度のほぼ中性域では非常に安定性が高いのであるが、pHが8.5を超えるあたりから溶解性が高くなる。船舶用鋼材が曝される海水は、清浄な場合にはpHは8程度であるが、海藻などが繁殖している海域ではpHは9.5程度にまでアルカリ化することがある。また、腐食のカソード反応が起こっているサイトでは溶存酸素の還元で生成したOHイオンのためpHが上昇する傾向にある。こうしたことから、船舶環境でのAl酸化物は必ずしも安定には存在できず、むしろ容易に溶解してその保護性が得られる場合の方が多い。これに対して、Cr酸化物はアルカリ領域での安定性が高いことに加えて、微量に溶解したCrイオンの加水分解平衡でpHを低下させる効果がるため、海水のpH上昇によるAl酸化物の溶解を抑止して、その保護性を確保する作用を発揮することになる。従って、Cr酸化物とAl酸化物とが適切な量で共存することによって、鋼材の防食効果は相乗的に高くなるものと考えられる。 The Al oxide film has a very high stability in a substantially neutral range where the pH is about 5 to 8.5, but the solubility becomes high when the pH exceeds 8.5. Seawater to which marine steel materials are exposed has a pH of about 8 when it is clean, but may be alkalized to a pH of about 9.5 in sea areas where seaweed and the like are breeding. Further, at the site where the cathodic reaction of corrosion occurs, the pH tends to increase due to OH ions generated by the reduction of dissolved oxygen. For these reasons, Al oxides in a marine environment cannot always exist stably, but rather are more easily dissolved to obtain their protective properties. In contrast, Cr oxide has high stability in the alkaline region, and also has the effect of lowering the pH by hydrolysis equilibrium of a very small amount of dissolved Cr ions. Inhibiting the dissolution of the resin and exerting the effect of securing its protective property. Therefore, it is considered that the anticorrosive effect of the steel material is synergistically enhanced by the coexistence of Cr oxide and Al oxide in appropriate amounts.

こうした効果は、後述する適切な量に制御することによって発揮されることになるのであるが、これらの含有量の比の値([Cr]/[Al]:質量比)も適切に制御することが必要である。即ち、この値([Cr]/[Al])が1未満であると、腐食均一性が不十分となりやすく、50を超えると耐すきま腐食性が不十分となる。この[Cr]/[Al]の値は、より好ましくは10〜35程度とするのが良い。   Such an effect is exhibited by controlling to an appropriate amount described later, but the value of the ratio of these contents ([Cr] / [Al]: mass ratio) is also appropriately controlled. is required. That is, if this value ([Cr] / [Al]) is less than 1, corrosion uniformity tends to be insufficient, and if it exceeds 50, crevice corrosion resistance becomes insufficient. The value of [Cr] / [Al] is more preferably about 10 to 35.

本発明の鋼材では、その鋼材としての基本的特性を満足させるために、C,Si,Mn,Cu,Ni,Co,Ti,Ca,Mg,P,S等の成分も適切に調整する必要がある。これらの成分の範囲限定理由について、上記Al,Crの各元素による作用効果と共に、次に示す。   In the steel material of the present invention, it is necessary to appropriately adjust components such as C, Si, Mn, Cu, Ni, Co, Ti, Ca, Mg, P, and S in order to satisfy the basic characteristics as the steel material. is there. The reasons for limiting the ranges of these components will be described below together with the effects of the above-described Al and Cr elements.

[C:0.04〜0.18%]
Cは、材料の強度確保のために必要な元素である。船舶の構造部材としての最低強度、即ち概ね400MPa程度(使用する鋼材の肉厚にもよるが)を得るためには、0.04%以上含有させる必要がある。しかし、0.18%を超えて過剰に含有させると靱性が劣化する。こうしたことから、C含有量の範囲は0.04〜0.18%とした。尚、C含有量の好ましい下限は0.08%である。また、C含有量の好ましい上限は0.16%である。
[C: 0.04 to 0.18%]
C is an element necessary for ensuring the strength of the material. In order to obtain the minimum strength as a structural member of a ship, that is, about 400 MPa (depending on the thickness of the steel material used), it is necessary to contain 0.04% or more. However, if the content exceeds 0.18%, the toughness deteriorates. For these reasons, the C content range was 0.04 to 0.18%. In addition, the minimum with preferable C content is 0.08%. Moreover, the upper limit with preferable C content is 0.16%.

[Si:0.10〜0.50%]
Siは脱酸と強度確保のための必要な元素であり、0.10%に満たないと構造部材としての最低強度を確保できない。しかし、0.50%を超えて過剰に含有させると溶接性が劣化する。尚、Si含有量の好ましい上限は0.40%であり、より好ましくは0.30%以下とするのが良い。
[Si: 0.10 to 0.50%]
Si is a necessary element for deoxidation and securing strength, and the minimum strength as a structural member cannot be secured unless it is less than 0.10%. However, if the content exceeds 0.50%, the weldability deteriorates. In addition, the upper limit with preferable Si content is 0.40%, More preferably, it is good to set it as 0.30% or less.

[Mn:0.10〜1.80%]
MnもSiと同様に脱酸および強度確保のために必要であり、0.10%に満たないと構造部材としての最低強度を確保できない。しかし、1.80%を超えて過剰に含有させると靱性が劣化する。尚、Mn含有量の好ましい上限は1.60%である。
[Mn: 0.10 to 1.80%]
Mn is also necessary for deoxidation and securing strength in the same manner as Si, and if it is less than 0.10%, the minimum strength as a structural member cannot be secured. However, if the content exceeds 1.80%, the toughness deteriorates. In addition, the preferable upper limit of Mn content is 1.60%.

[Al:0.05〜0.50%]
上述したように、Alは表面に安定な酸化物防食皮膜を形成する効果がある。Al含有量が少なくなると、腐食溶解したAl3+イオンは海水中に飛散して鋼材表面に堆積されず、防食皮膜が形成されないことになる。Cr酸化物との共存下で十分な防食効果を発揮させるためには、Alは0.05%以上含有させる必要がある。通常の鋼材であれば、Al含有量が0.10%を超えると溶接部の靭性がやや低下するなど溶接性の点で問題があったが、本発明の鋼材のようにC,Si,P,Sを適正範囲とすることによって、Al含有量が0.1%超〜0.50%までの範囲であっても従来鋼と同等の溶接性を確保することができる。しかしながら、Al含有量が0.50%を超えて過剰になると、溶接性を害することになる。こうしたことから、Al含有量の範囲は0.05〜0.50%とした。尚、Al含有量の好ましい下限は0.08%であり、より好ましくは0.10%以上とするのが良い。また、Al含有量の好ましい上限は0.45%であり、より好ましくは0.40%以下とするのが良い。
[Al: 0.05 to 0.50%]
As described above, Al has an effect of forming a stable oxide anticorrosive film on the surface. When the Al content decreases, the corrosion-dissolved Al 3+ ions are scattered in the seawater and are not deposited on the surface of the steel material, so that an anticorrosion film is not formed. In order to exhibit a sufficient anticorrosion effect in the presence of Cr oxide, Al needs to be contained in an amount of 0.05% or more. In the case of a normal steel material, if the Al content exceeds 0.10%, there is a problem in weldability such as a decrease in the toughness of the welded portion, but C, Si, P like the steel material of the present invention. By setting S and S within the proper range, weldability equivalent to that of conventional steel can be ensured even when the Al content is in the range of more than 0.1% to 0.50%. However, when the Al content exceeds 0.50% and becomes excessive, weldability is impaired. For these reasons, the range of Al content is set to 0.05 to 0.50%. In addition, the minimum with preferable Al content is 0.08%, More preferably, it is good to set it as 0.10% or more. Moreover, the upper limit with preferable Al content is 0.45%, More preferably, it is good to set it as 0.40% or less.

[Cu:0.05〜4.00%]
Cuは、耐食性向上に大きく寄与する緻密な表面錆皮膜を形成するのに有効な元素である。また、Cuを含有させることによって形成される緻密な錆皮膜とAl酸化物とCr酸化物とが共存する安定な酸化物防食皮膜とが母材の保護性を相乗的に高めて、優れた耐食性が発揮されることになる。こうした効果を発揮させるためには、0.05%以上含有させることが必要であるが、過剰に含有させると溶接性や熱間加工性が劣化することから、4.00%以下とする必要がある。
[Cu: 0.05 to 4.00%]
Cu is an element effective for forming a dense surface rust film that greatly contributes to the improvement of corrosion resistance. In addition, the dense rust film formed by containing Cu and the stable oxide anticorrosive film in which Al oxide and Cr oxide coexist synergistically enhance the protection of the base material, and have excellent corrosion resistance. Will be demonstrated. In order to exert such effects, it is necessary to contain 0.05% or more, but if it is contained excessively, weldability and hot workability deteriorate, so it is necessary to make it 4.00% or less. is there.

[Cr:0.05〜4.50%]
Crは、Alと同様に表面に安定な酸化物皮膜を形成して鋼材を防食する効果を発揮する。本発明では上述のように、Al酸化物とCr酸化物を共存させることによって、鋼材の耐食性が飛躍的に向上することになるのであるが、こうした効果を発揮させるためには、0.05%以上含有させる必要がある。しかしながら、過剰に含有させると溶接性が劣化することから、4.50%以下とする必要がある。
[Cr: 0.05 to 4.50%]
Cr, like Al, exhibits the effect of forming a stable oxide film on the surface and preventing corrosion of the steel material. In the present invention, as described above, the coexistence of Al oxide and Cr oxide will drastically improve the corrosion resistance of the steel material. It is necessary to contain above. However, if it is contained excessively, weldability deteriorates, so it is necessary to be 4.50% or less.

[Ni:0.05〜5.0%、Co:0.01〜5.0%およびTi:0.008〜0.20%よりなる群から選ばれる2種以上]
Ni,CoおよびTiは、いずれも耐食性向上に有効な元素である。このうちNiおよびCoは、耐食性向上に大きく寄与する緻密な表面錆皮膜を形成するのに有効な元素である。こうした効果を発揮させるためには、Niで0.05%以上、Coで0.01%以上含有させる必要があるが、過剰に含有させると溶接性や熱間加工性が劣化することから、5.0%以下とする必要がある。Coを含有させるときの好ましい下限は0.05%であり、NiおよびCoの好ましい上限は4.50%である。
[2 or more selected from the group consisting of Ni: 0.05 to 5.0%, Co: 0.01 to 5.0% and Ti: 0.008 to 0.20%]
Ni, Co and Ti are all effective elements for improving corrosion resistance. Among these, Ni and Co are effective elements for forming a dense surface rust film that greatly contributes to the improvement of corrosion resistance. In order to exert such an effect, it is necessary to contain 0.05% or more of Ni and 0.01% or more of Co. However, if contained excessively, weldability and hot workability deteriorate. 0.0% or less is necessary. A preferable lower limit when Co is contained is 0.05%, and a preferable upper limit of Ni and Co is 4.50%.

Tiは耐食性向上に大きく寄与する表面錆皮膜を緻密化してその環境遮断性を向上させると共に、すきま内部における腐食を抑制して、耐すきま腐食性も向上させる元素である。こうした環境下で要求される耐食性を確保するためには、0.008%以上含有させることが好ましいが、0.20%を超えて過剰に含有させると加工性と溶接性を劣化させることになる。Tiの好ましい上限は0.15%である。   Ti is an element that densifies the surface rust film, which greatly contributes to the improvement of corrosion resistance, improves its environmental barrier properties, suppresses corrosion inside the crevice, and improves crevice corrosion resistance. In order to ensure the corrosion resistance required in such an environment, it is preferable to contain 0.008% or more, but if it exceeds 0.20%, workability and weldability are deteriorated. . A preferable upper limit of Ti is 0.15%.

[Ca:0.0010〜0.015%および/またはMg:0.0005〜0.020%]
CaおよびMgは、溶解することによってpH上昇作用を示し、鉄の溶解が起こっている局部アノードにおける加水分解反応によるpH低下を抑制して腐食反応を抑制し、耐食性向上に有効な元素である。こうした効果は、Caで0.0010%以上、Mgで0.0005%以上含有させることによって有効に発揮されるが、Caで0.015%を超えて、Mgで0.020%を超えて過剰に含有させると、加工性と溶接性とを劣化させることになる。Mgの好ましい下限は0.0010%であり、より好ましい上限は0.015%である。
[Ca: 0.0010 to 0.015% and / or Mg: 0.0005 to 0.020%]
Ca and Mg are elements that are effective in improving corrosion resistance by exhibiting a pH raising action when dissolved, suppressing a pH drop due to a hydrolysis reaction at a local anode where iron is dissolved, and suppressing a corrosion reaction. Such an effect is effectively exerted by adding 0.0010% or more of Ca and 0.0005% or more of Mg, but it exceeds 0.015% for Ca and exceeds 0.020% for Mg. When it is contained, the workability and weldability are deteriorated. A preferable lower limit of Mg is 0.0010%, and a more preferable upper limit is 0.015%.

[P:0.020%以下(0%を含む)]
Pは靭性や溶接性を劣化させる元素であり、可能な限り含有量を抑えることが好ましい。P含有量の許容される上限は0.020%までであり、これを超えると船舶用鋼材としての溶接性を確保できない。こうしたことから、P含有量は0.020%以下とした。尚、P含有量の好ましい上限は0.015%である。
[P: 0.020% or less (including 0%)]
P is an element that deteriorates toughness and weldability, and the content is preferably suppressed as much as possible. The allowable upper limit of the P content is 0.020%, and if it exceeds this, weldability as marine steel cannot be ensured. For these reasons, the P content is set to 0.020% or less. In addition, the preferable upper limit of P content is 0.015%.

[S:0.010%以下(0%を含む)]
SもPと同様に靭性や溶接性を劣化させる元素であり、可能な限り含有量を抑えることが好ましい。S含有量の許容される上限は0.010%までであり、これを超えると船舶用鋼材としての溶接性を確保できない。こうしたことから、S含有量は0.010%以下とした。尚、S含有量の好ましい上限は0.008%である。
[S: 0.010% or less (including 0%)]
S, like P, is an element that deteriorates toughness and weldability, and the content is preferably suppressed as much as possible. The allowable upper limit of the S content is 0.010%, and if it exceeds this, the weldability as a marine steel material cannot be ensured. For these reasons, the S content is set to 0.010% or less. In addition, the upper limit with preferable S content is 0.008%.

本発明の船舶用鋼材における基本成分は上記の通りであり、残部は鉄および不可避的不純物(例えば、O等)からなるものであるが、これら以外にも鋼材の特性を阻害しない程度の成分(例えば、Zr,N等)も許容できる。但し、これら許容成分は、その量が過剰になると靭性が劣化するので、0.1%程度以下に抑えるべきである。   The basic components in the marine steel of the present invention are as described above, and the balance is composed of iron and unavoidable impurities (for example, O, etc.). For example, Zr, N, etc.) are acceptable. However, these allowable components should be suppressed to about 0.1% or less because their toughness deteriorates when the amount is excessive.

また、本発明の船舶用鋼材には、上記成分の他必要によって、(1)Se:0.005〜0.50%、(2)Sb:0.01〜0.50%および/またはSn:0.01〜0.50%、(3)Nb:0.003〜0.50%、等を含有させることも有効であり、含有させる成分の種類に応じて船舶用鋼材の特性が更に改善されることになる。   Further, in the marine steel material of the present invention, (1) Se: 0.005 to 0.50%, (2) Sb: 0.01 to 0.50% and / or Sn: It is also effective to contain 0.01 to 0.50%, (3) Nb: 0.003 to 0.50%, etc., and the characteristics of marine steel materials are further improved according to the type of components to be contained. Will be.

[Se:0.005〜0.50%]
Seは腐食の溶解反応が起こっているサイトのpH低下を抑制して腐食反応を抑制し、耐食性を向上させる作用を発揮する元素である。こうしたSeを含有させることによって、局部的なpH変化が起こりにくくなるため、腐食均一性が向上する作用がある。また、物質移動が制限されている局所的はpH低下が起こりやすい「すきま部」においては、上記した理由によってその効果(局部腐食抑制効果)が有効に発揮される。こうした環境で要求される耐食性を確保するためには、Seの含有量は0.005%以上とすることが好ましい。しかしながら、0.50%を超えて過剰に含有させると加工性と溶接性が劣化する。こうしたことからSe含有量は、0.005〜0.50%とした。尚、Se含有量のより好ましい下限は0.008%であり、更に好ましくは0.010%以上とするのが良い。また、Se含有量より好ましい上限は0.45%であり、更に好ましくは0.40%以下とするのが良い。
[Se: 0.005 to 0.50%]
Se is an element that exerts the action of suppressing the corrosion reaction by suppressing the pH drop of the site where the corrosion dissolution reaction occurs, and improving the corrosion resistance. Inclusion of such Se makes it difficult for local pH changes to occur, and thus has an effect of improving corrosion uniformity. In addition, in the “gap portion” where the mass transfer is restricted and the pH is likely to decrease, the effect (local corrosion inhibition effect) is effectively exhibited for the reason described above. In order to ensure the corrosion resistance required in such an environment, the Se content is preferably 0.005% or more. However, if the content exceeds 0.50%, workability and weldability deteriorate. For these reasons, the Se content is set to 0.005 to 0.50%. A more preferable lower limit of the Se content is 0.008%, and more preferably 0.010% or more. Moreover, a preferable upper limit from the Se content is 0.45%, and more preferably 0.40% or less.

[Sb:0.01〜0.50%および/またはSn:0.01〜0.50%]
SbおよびSnは、Cu,Ni,Ti等による生成錆緻密化作用や、Se,Ca,Mg等によるpH低下作用を助長して耐食性を向上させる元素である。こうした作用を発揮させるためには、いずれも0.01%以上含有させることが好ましいが、過剰に含有させると加工性と溶接性が劣化することから、0.50%以下とすることが好ましい。これらの元素を含有させるときのより好ましい下限はいずれも0.02%であり、より好ましい上限は0.40%である。
[Sb: 0.01 to 0.50% and / or Sn: 0.01 to 0.50%]
Sb and Sn are elements that enhance the corrosion resistance by promoting the effect of densification of rust produced by Cu, Ni, Ti, etc., and the effect of lowering the pH by Se, Ca, Mg, etc. In order to exert such an effect, it is preferable to contain 0.01% or more in any case. However, if excessively contained, workability and weldability deteriorate, so 0.50% or less is preferable. The more preferable lower limit when these elements are contained is 0.02%, and the more preferable upper limit is 0.40%.

[B:0.0001〜0.010%、V:0.01〜0.50%およびNb:0.003〜0.50%よりなる群から選ばれる1種以上]
船舶用鋼材では、適用する部位によってはより高強度化が必要な場合があるが、これらの元素は強度向上に必要な元素である。このうちBは、0.0001%以上含有させることによって焼入性が向上して強度向上に有効であるが、0.010%を超えて過剰に含有させると母材靭性が劣化するため好ましくない。Vは、0.01%以上含有させることによって強度向上に有効であるが、0.50%を超えて過剰に含有させると鋼材の靭性劣化を招くことになるので好ましくない。Nbは、0.003%以上含有させることによって強度向上に有効であるが、0.50%を超えて過剰に含有させると鋼材の靭性劣化を招くことになる。尚、これらの元素のより好ましい下限は、Bについては0.0003%、Vについては0.02%、Nbについては0.005%である。またより好ましい上限はBについては0.0090%、Vについては0.45%、Nbについては0.45%である。
[B: one or more selected from the group consisting of 0.0001 to 0.010%, V: 0.01 to 0.50% and Nb: 0.003 to 0.50%]
In marine steel materials, higher strength may be required depending on the site to be applied, but these elements are elements necessary for strength improvement. Of these, B is contained in an amount of 0.0001% or more, which improves the hardenability and is effective in improving the strength. However, if it is contained in excess of 0.010%, the base material toughness deteriorates, which is not preferable. . V is effective for improving the strength by containing 0.01% or more, but if it exceeds 0.50%, it is not preferable because it causes toughness deterioration of the steel material. Nb is effective for improving the strength by containing 0.003% or more, but if it exceeds 0.50% and it is contained excessively, the toughness of the steel will be deteriorated. More preferable lower limits of these elements are 0.0003% for B, 0.02% for V, and 0.005% for Nb. The more preferable upper limit is 0.0090% for B, 0.45% for V, and 0.45% for Nb.

本発明の船舶用鋼材は、基本的には塗装を施さなくても鋼材自体が優れた耐食性を発揮するものであるが、必要によって、後記実施例に示すタールエポキシ樹脂塗料、或はそれ以外の代表される重防食塗装、ジンクリッチペイント、ショッププライマーなどの他の防食方法と併用することも可能である。こうした防食塗装を施した場合には、後記実施例に示すように塗装膜自体の耐食性(塗装耐食性)も良好なものとなる。   The marine steel material of the present invention basically exhibits excellent corrosion resistance even if it is not coated, but if necessary, the tar epoxy resin paint shown in the examples below, or other than that It can also be used in combination with other anticorrosion methods such as representative heavy anticorrosion coating, zinc rich paint, shop primer. When such anticorrosion coating is applied, the corrosion resistance of the coating film itself (coating corrosion resistance) is also good as shown in the examples described later.

以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも勿論可能であり、それらはいずれも本発明の技術的範囲に包含されるものである。   EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

下記表1、2に示す化学成分組成の鋼材を転炉で溶製し、連続鋳造および熱間圧延により各種鋼板を作製した。得られた鋼板を切断および表面研削を行って、最終的に100×100×25(mm)の大きさの試験片を作製した(試験片A)。試験片Aの外観形状を図1に示す。   Steel materials having chemical composition shown in Tables 1 and 2 below were melted in a converter, and various steel plates were produced by continuous casting and hot rolling. The obtained steel plate was cut and subjected to surface grinding to finally produce a test piece having a size of 100 × 100 × 25 (mm) (test piece A). The external shape of the test piece A is shown in FIG.

また、図2に示すように20×20×5(mm)の小試験片4個を、100×100×25(mm)の大試験片(前記試験片Aと同じもの)に接触させて、すきま部を形成した試験片Bを作製した。すきま形成用の小試験片と大試験片とは同じ化学成分組成の鋼材として、表面仕上げも前記試験片Aと同じ表面研削とした。そして小試験片の中心に5mmφの孔を、基材側(大試験片側)にねじ孔を開けて、M4プラスチック製ねじで固定した。   Further, as shown in FIG. 2, four small test pieces of 20 × 20 × 5 (mm) are brought into contact with a large test piece of 100 × 100 × 25 (mm) (the same as the test piece A), A test piece B having a clearance was formed. The small test piece and the large test piece for forming the gap were steel materials having the same chemical composition, and the surface finish was the same as that of the test piece A. Then, a hole of 5 mmφ was formed in the center of the small test piece, and a screw hole was made on the base material side (large test piece side), and fixed with an M4 plastic screw.

更に、平均厚さ250μmのタールエポキシ樹脂塗装(下塗り:ジンクリッチプライマー)を全面に施した試験片C(図3)も用いた。そして防食のための塗膜に傷が付いて素地の鋼材が露出した場合の腐食進展度合いを調べるために、試験片Cの片面には素地まで達するカット傷(長さ:100mm、幅:約0.5mm)をカッターナイフで形成した。   Further, a test piece C (FIG. 3) on which an entire thickness of 250 μm thick tar epoxy resin coating (undercoating: zinc rich primer) was applied was used. Then, in order to investigate the degree of corrosion progress when the base steel material is exposed due to scratches on the anticorrosion coating film, the cut surface reaching the base on one side of the test piece C (length: 100 mm, width: about 0) 0.5 mm) was formed with a cutter knife.

前記表1、2に示した各化学成分組成の供試材について、試験片A、試験片Bおよび試験片Cを夫々5個ずつ用い腐食試験に供した。このときの腐食試験方法は次の通りである。   About the test material of each chemical component composition shown in the said Table 1, 2, the test piece A, the test piece B, and five test pieces C were used for the corrosion test, respectively. The corrosion test method at this time is as follows.

[腐食試験方法]
電気防食が作用しないバラストタンク内の上部などの湿潤の大気雰囲気を模擬して、海塩粒子を付着させて湿潤状態に保持する腐食試験を行った(腐食試験A)。また、兵庫県加古川市にて採取した実海水7.5mLをほぼ均一に試験面に滴下して、乾燥させた試験片を温度:50℃、湿度:95%RHの恒温恒湿試験槽内に水平に設置して腐食させた。試験時間は6ヶ月間であり、1ヶ月毎に実海水5.0mLを追加で試験面に滴下した。この試験には、前記試験片Aおよび試験片Bを用いて、耐全面腐食性、腐食均一性および耐すきま腐食性を評価した。
[Corrosion test method]
A corrosion test was conducted in which a moist air atmosphere such as the upper part of the ballast tank where the cathodic protection does not act was simulated and the sea salt particles were adhered and kept in a wet state (corrosion test A). In addition, 7.5 mL of real seawater collected in Kakogawa City, Hyogo Prefecture, was dripped almost uniformly onto the test surface, and the dried test piece was placed in a constant temperature and humidity test tank with a temperature of 50 ° C. and a humidity of 95% RH. Installed horizontally and corroded. The test time was 6 months, and 5.0 mL of actual seawater was added dropwise to the test surface every month. In this test, the test piece A and the test piece B were used to evaluate the general corrosion resistance, the corrosion uniformity, and the crevice corrosion resistance.

また原油タンク内の上甲板の腐食環境を模擬して、温度を50℃に保持した試験槽内に試験片を水平に設置して、組成:5vol%O2−10vol%CO2−0.01vol%SO2−0.30vol%H2Sの腐食性ガスを1L/min通気させて試験片を腐食させた(腐食試験B)。このとき、試験槽内は常時水蒸気飽和状態となるように湿度は98%RH以上に制御して、湿潤状態を保持した。試験時間は6ヶ月間である。この試験には、1ヶ月毎に実海水5.0mLを追加で試験面に滴下した。この試験には、前記試験片Aおよび試験片Cを用いて、耐全面腐食性、腐食均一性および塗装腐食性を評価した。 In addition, by simulating the corrosive environment of the upper deck in the crude oil tank, a test piece was horizontally installed in a test tank maintained at a temperature of 50 ° C., and the composition was 5 vol% O 2 -10 vol% CO 2 -0.01 vol. The test piece was corroded by passing 1 L / min of corrosive gas of% SO 2 -0.30 vol% H 2 S (corrosion test B). At this time, the humidity was controlled to 98% RH or higher so that the inside of the test tank was always saturated with water vapor, and the wet state was maintained. The test time is 6 months. In this test, 5.0 mL of actual seawater was additionally dropped on the test surface every month. In this test, the test piece A and the test piece C were used to evaluate the general corrosion resistance, the corrosion uniformity, and the paint corrosion resistance.

(1)試験片Aについては、試験前後の重量変化を平均板厚減少量D-ave(mm)に換算し、試験片5個の平均値を算出して、各供試材の全面腐食性を評価した。また、触針式三次元形状測定装置を用いて試験片Aの最大侵食深さD-max(mm)を求め、平均板厚減少量[D-ave(mm)]で規格化して(即ち、D-max/D-aveを算出して)、腐食均一性を評価した。尚、試験後の重量測定および板厚測定は、クエン酸水素二アンモニウム水溶液中での陰極電解法[JIS K8284]により鉄錆等の腐食生成物を除去してから行った。
(2)試験片Bについては、すきま部(接触面)の目視観察を行ってすきま腐食発生の有無を調べ、すきま腐食が認められる場合には、上記陰極電解法により腐食生成物を除去し、触針式三次元形状測定装置を用いて最大すきま腐食深さD-crev(mm)を測定した。
(3)塗装処理を施した試験片C(カット傷付き)については、カット傷に垂直方向の塗膜膨れ幅をノギスで測定し、試験片5個の最大値を最大膨れ幅と定義した。
(1) For test piece A, the weight change before and after the test is converted into the average thickness reduction D-ave (mm), the average value of the five test pieces is calculated, and the overall corrosivity of each specimen is calculated. Evaluated. Further, the maximum erosion depth D-max (mm) of the test piece A is obtained using a stylus type three-dimensional shape measuring apparatus, and normalized by the average thickness reduction amount [D-ave (mm)] (that is, D-max / D-ave was calculated) and corrosion uniformity was evaluated. In addition, the weight measurement and the plate thickness measurement after the test were performed after removing corrosion products such as iron rust by the cathodic electrolysis method [JIS K8284] in an aqueous solution of diammonium hydrogen citrate.
(2) For test piece B, the crevice portion (contact surface) was visually observed to check for crevice corrosion. If crevice corrosion was observed, the corrosion product was removed by the cathodic electrolysis method, The maximum crevice corrosion depth D-crev (mm) was measured using a stylus type three-dimensional shape measuring apparatus.
(3) About the test piece C (with cut flaws) which performed the coating process, the coating film swollen width of the perpendicular | vertical direction to a cut flaw was measured with calipers, and the maximum value of five test pieces was defined as the maximum swollen width.

上記耐全面腐食性(D-ave)、腐食均一性(D-max/D-ave)、耐すきま腐食性(D-crev)、塗装耐食性(膨れ面積率および最大膨れ幅)の評価基準は下記表3に示す通りである。腐食試験結果を下記表4、5に示す。   The evaluation criteria for the above general corrosion resistance (D-ave), corrosion uniformity (D-max / D-ave), crevice corrosion resistance (D-crev), and coating corrosion resistance (blowing area ratio and maximum swollen width) are as follows: As shown in Table 3. The corrosion test results are shown in Tables 4 and 5 below.

これらの結果から次のように考察できる。まずいずれの腐食試験においても、Al,CuおよびCrの含有量が本発明で規定する適正範囲に満足しない場合(No.2〜6)には、従来の普通鋼(No.1)に比べて耐全面腐食性はやや改善している。しかしながら、腐食均一性と塗装耐食性については、改善効果は認められない。   These results can be considered as follows. First, in any corrosion test, when the content of Al, Cu and Cr is not satisfied within the appropriate range specified in the present invention (No. 2 to 6), compared with the conventional ordinary steel (No. 1). Overall corrosion resistance is slightly improved. However, no improvement effect is observed with respect to corrosion uniformity and coating corrosion resistance.

これに対して、Al、CuおよびCrを適性量含有させたもの(No.7〜43)はこれらの元素の添加による相乗効果でいずれの耐食性が大きく向上しており、腐食均一性、耐すきま腐食性および塗装耐食性も向上していることが分かる。こうした耐食性向上には、Al酸化物とCr酸化物とが共存する安定な酸化物防食皮膜と、Cu含有により形成される緻密な錆皮膜の保護作用が相乗的に寄与しているものと考えられた。   On the other hand, those containing appropriate amounts of Al, Cu and Cr (Nos. 7 to 43) have greatly improved any corrosion resistance due to the synergistic effect due to the addition of these elements. It can be seen that the corrosion resistance and paint corrosion resistance are also improved. It is thought that the protective action of the stable oxide corrosion protective film in which Al oxide and Cr oxide coexist and the dense rust film formed by containing Cu synergistically contribute to such corrosion resistance improvement. It was.

このうちAl、CuおよびCrの併用に加えて、更にNi,Co,Ti,Ca,Mg等の耐食性向上元素を含有させることによって(No.11〜15)、鋼材の耐全面腐食性が大幅に向上していることが分かる。特に、CaやMgを含有させることによって、腐食均一性や耐すきま腐食性の向上が認められており(No.14〜15)、これらの元素の局部pH低下の抑制作用によって局所的な腐食が抑制されたものと推察される。   Among these, in addition to the combined use of Al, Cu and Cr, by further containing an element for improving corrosion resistance such as Ni, Co, Ti, Ca, Mg, etc. (No. 11-15), the overall corrosion resistance of the steel material is greatly increased. It can be seen that it has improved. In particular, inclusion of Ca and Mg has been confirmed to improve corrosion uniformity and crevice corrosion resistance (No. 14 to 15), and local corrosion is prevented by the action of suppressing the local pH drop of these elements. Inferred to have been suppressed.

またNi,Co或いはTiを含有することによって、塗装耐食性の向上効果が認められ(No.11〜13等)、これらの元素の錆緻密化作用の相乗効果により塗膜傷部における腐食進行が阻止されたものと推察される。   Also, by containing Ni, Co or Ti, the effect of improving the coating corrosion resistance is recognized (No. 11 to 13 etc.), and the progress of corrosion at the scratches on the coating film is prevented by the synergistic effect of the rust densification action of these elements. It is inferred that

更に、Seを含有させることによって、耐食性は大幅に向上することが明らかであり(No.35,36等)、Seによる局所的なpH変化の抑制効果がすきま腐食等の局部腐食に対する耐食性の向上に寄与しているものと考えられた。尚、No.7,8,9,10等の結果から明らかなように、([Cr]/[Al])の値を適切に調整することによって、各種耐食性が大幅に優れる結果となっていることが分かる。   Furthermore, it is clear that the corrosion resistance is greatly improved by containing Se (No. 35, 36, etc.), and the effect of suppressing local pH change by Se is improved in corrosion resistance against local corrosion such as crevice corrosion. It was thought that it contributed to. No. As is apparent from the results of 7, 8, 9, 10, etc., it can be seen that by appropriately adjusting the value of ([Cr] / [Al]), various corrosion resistances are greatly improved.

耐食性試験に用いた試験片Aの外観形状を示す説明図である。It is explanatory drawing which shows the external appearance shape of the test piece A used for the corrosion resistance test. 耐食性試験に用いた試験片Bの外観形状を示す説明図である。It is explanatory drawing which shows the external appearance shape of the test piece B used for the corrosion resistance test. 耐食性試験に用いた試験片Cの外観形状を示す説明図である。It is explanatory drawing which shows the external appearance shape of the test piece C used for the corrosion resistance test.

Claims (4)

C:0.04〜0.18%(質量%の意味、以下同じ)、Si:0.10〜0.50%、Mn:0.10〜1.80%、Al:0.05〜0.50%、Cu:0.05〜4.00%、Cr:0.05〜4.50%を夫々含有する他、Ni:0.05〜5.0%、Co:0.01〜5.0%およびTi:0.008〜0.20%よりなる群から選ばれる2種以上を含有し、更にCa:0.0010〜0.015%および/またはMg:0.0005〜0.020%を含有し、P:0.020%以下(0%を含む)およびS:0.010%以下(0%を含む)に夫々抑制し、残部がFeおよび不可避的不純物からなり、且つCrの含有量[Cr]とAlの含有量[Al]の比の値([Cr]/[Al])が1〜50であることを特徴とする湿潤の大気雰囲気での耐すきま腐食性に優れた船舶用鋼材。 C: 0.04 to 0.18% (meaning of mass%, the same applies hereinafter), Si: 0.10 to 0.50%, Mn: 0.10 to 1.80%, Al: 0.05 to 0. 50%, Cu: 0.05 to 4.00%, Cr: 0.05 to 4.50%, Ni: 0.05 to 5.0%, Co: 0.01 to 5.0 % And Ti: two or more selected from the group consisting of 0.008 to 0.20%, Ca: 0.0010 to 0.015% and / or Mg: 0.0005 to 0.020% P: 0.020% or less (including 0%) and S: 0.010% or less (including 0%), respectively, with the balance being Fe and inevitable impurities, and Cr content The ratio of [Cr] to Al content [Al] ([Cr] / [Al]) is 1 to 50. Crevice corrosion resistance excellent marine steel atmosphere. 更に、Se:0.005〜0.50%を含有する請求項1に記載の船舶用鋼材。   Furthermore, the steel materials for ships of Claim 1 containing Se: 0.005-0.50%. 更に、Sb:0.01〜0.50%および/またはSn:0.01〜0.50%を含有する請求項1または2に記載の船舶用鋼材。   The marine steel material according to claim 1 or 2, further comprising Sb: 0.01 to 0.50% and / or Sn: 0.01 to 0.50%. 更に、B:0.0001〜0.010%、V:0.01〜0.50%およびNb:0.003〜0.50%よりなる群から選ばれる1種以上を含有する請求項1〜3のいずれかに記載の船舶用鋼材。   Furthermore, it contains at least one selected from the group consisting of B: 0.0001 to 0.010%, V: 0.01 to 0.50% and Nb: 0.003 to 0.50%. 4. The marine steel material according to any one of 3 above.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7662735B2 (en) 2002-08-02 2010-02-16 3M Innovative Properties Company Ceramic fibers and composites comprising same
US7737063B2 (en) 2001-08-02 2010-06-15 3M Innovative Properties Company AI2O3-rare earth oxide-ZrO2/HfO2 materials, and methods of making and using the same
US7799444B2 (en) 2004-09-29 2010-09-21 Schott Ag Conversion material
US7910505B2 (en) 2006-06-06 2011-03-22 Schott Ag Sintered glass ceramic and method for producing the same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7737063B2 (en) 2001-08-02 2010-06-15 3M Innovative Properties Company AI2O3-rare earth oxide-ZrO2/HfO2 materials, and methods of making and using the same
US7662735B2 (en) 2002-08-02 2010-02-16 3M Innovative Properties Company Ceramic fibers and composites comprising same
US7799444B2 (en) 2004-09-29 2010-09-21 Schott Ag Conversion material
US7910505B2 (en) 2006-06-06 2011-03-22 Schott Ag Sintered glass ceramic and method for producing the same
US8039407B2 (en) 2006-06-06 2011-10-18 Schott Ag Sintered glass ceramic and method for producing the same

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