JP2006009128A5

JP2006009128A5 -

Info

Publication number: JP2006009128A5
Application number: JP2004191758A
Authority: JP
Filing date: 2004-06-29
Publication date: 2006-08-24
Anticipated expiration: 2024-06-29

Description

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, 2000-17181, 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、特にすきま腐食に対する耐久性の向上を図ると共に、海水に起因する塩分付着と湿潤環境による腐食に対しても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, particularly durability against crevice corrosion. An object of the present invention is to provide a marine steel material that is improved and exhibits excellent durability against salt adhesion caused by seawater and corrosion caused by a moist environment.

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：０．０１〜０．３０％(質量％の意味、以下同じ)、Ｓｉ：０．０１〜１．５０％、Ｍｎ：０．０１〜２．０％、Ａｌ：０．００５〜０．１０％を夫々含有する他、Ｃｏ：０．０１〜５．００％およびＭｇ：０．０００５〜０．０２０％を含有し、残部がＦｅおよび不可避的不純物からなり、且つＣｏの含有量［Ｃｏ］とＭｇの含有量［Ｍｇ］の比の値（［Ｃｏ］／［Ｍｇ］）が２〜３５０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: 0.01 to 0.30% (meaning mass%, the same shall apply hereinafter), Si: 0.01 to 1.50%, Mn: 0.01% to 2.0%, Al: 0.005% to 0.10%, Co: 0.01% to 5.00% and Mg: 0.0005% to 0.020%, The remainder is composed of Fe and inevitable impurities, and the value of the ratio of Co content [Co] to Mg content [Mg] ([Co] / [Mg]) is 2 to 350. Is.

また本発明の船舶用鋼材においては、必要によって、（１）Ｃｕ：０．０１〜５．０％、Ｃｒ：０．０１〜５．０％、Ｎｉ：０．０１〜５．０％およびＴｉ：０．００５〜０．２０％よりなる群から選ばれる１種以上、（２）Ｃａ：０．０００５〜０．０２０％、（３）Ｍｏ：０．０１〜５．０％および／またはＷ：０．０１〜２．０％、（４）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。 Further, in the marine steel material of the present invention, (1) Cu: 0.01 to 5.0%, Cr: 0.01 to 5.0%, Ni: 0.01 to 5.0%, and Ti if necessary. : One or more selected from the group consisting of 0.005 to 0.20%, (2) Ca: 0.0005 to 0.020%, (3) Mo: 0.01 to 5.0% and / or W : Selected from the group consisting of 0.01 to 2.0%, (4) B: 0.0001 to 0.010%, V: 0.01 to 0.50% and Nb: 0.003 to 0.50% It is also effective to contain one or more of the above, and the characteristics of the marine steel will be further improved depending on the type of the component to be contained.

本発明においては、所定量のＣｏとＭｇ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材が実現でき、特にすきま腐食に対する耐久性の向上を図ると共に、海水に起因する塩分付着と湿潤環境による腐食に対しても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、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、バラストタンク、原油タンク等の素材として有用である。 In the present invention, a marine steel material having excellent corrosion resistance that can be put into practical use without being subjected to painting and anticorrosion by containing a predetermined amount of Co and Mg in combination and appropriately adjusting the chemical composition. In particular, marine steels that can improve the durability against crevice corrosion and exhibit excellent durability against salt adhesion caused by seawater and corrosion caused by a moist environment have been realized. Such marine steel materials are useful as raw materials for outer plates, ballast tanks, crude oil tanks 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ＣｏとＭｇ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 Co and Mg are contained in combination and the chemical composition is appropriately adjusted, thereby completing the present invention.

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、電気防食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 heavy duty anticorrosion coating, zinc rich paint, shop primer, and anticorrosion. 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.

これに対して、ＣｏおよびＭｇを併用して適性量含有させたもの（Ｎｏ．６〜３９）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も従来鋼（Ｎｏ．１）より優れており、船舶用鋼材として好ましいことがわかる。特に、ＣｏおよびＭｇの併用に加えて、更にＣｕ，Ｃｒ，Ｎｉ，Ｔｉ，Ｃａ，ＭｏおよびＷ等の耐食性向上元素を含有させることによって、鋼材の耐食性が更に向上していることが分かる。 On the other hand, those containing a suitable amount of Co and Mg in combination (Nos. 6 to 39) have a synergistic effect due to the addition of these elements, and are superior in corrosion resistance to the conventional steel (No. 1). It turns out that it is preferable as steel materials for ships. In particular, in addition to the combined use of Co and Mg, it can be seen that the corrosion resistance of the steel material is further improved by further containing a corrosion resistance improving element such as Cu, Cr, Ni, Ti, Ca, Mo and W.

Claims

Ｃ：０．０１〜０．３０％(質量％の意味、以下同じ)、Ｓｉ：０．０１〜１．５０％、Ｍｎ：０．０１〜２．０％、Ａｌ：０．００５〜０．１０％を夫々含有する他、Ｃｏ：０．０１〜５．００％およびＭｇ：０．０００５〜０．０２０％を含有し、残部がＦｅおよび不可避的不純物からなり、且つＣｏの含有量［Ｃｏ］とＭｇの含有量［Ｍｇ］の比の値（［Ｃｏ］／［Ｍｇ］）が２〜３５０であることを特徴とする耐食性に優れた船舶用鋼材。 C: 0.01-0.30% (meaning of mass%, the same applies hereinafter), Si: 0.01-1.50%, Mn: 0.01-2.0%, Al: 0.005-0. addition to each containing 10%, Co: 0.01~5.00% and Mg: containing from 0.0005 to 0.020%, Ri Do from the balance Fe and unavoidable impurities, and the content of Co [ A marine steel material excellent in corrosion resistance, characterized in that the value of the ratio of [Co] to Mg content [Mg] ([Co] / [Mg]) is 2 to 350 .

更に、Ｃｕ：０．０１〜５．０％、Ｃｒ：０．０１〜５．０％、Ｎｉ：０．０１〜５．０％およびＴｉ：０．００５〜０．２０％よりなる群から選ばれる１種以上を含有する請求項１に記載の船舶用鋼材。 Further, selected from the group consisting of Cu: 0.01 to 5.0%, Cr: 0.01 to 5.0%, Ni: 0.01 to 5.0% and Ti: 0.005 to 0.20% marine steel according to claim 1 containing one or more elements.

更に、Ｃａ：０．０００５〜０．０２０％を含有する請求項１または２に記載の船舶用鋼材。 Furthermore, the marine steel material of Claim 1 or 2 containing Ca: 0.0005-0.020%.

更に、Ｍｏ：０．０１〜５．０％および／またはＷ：０．０１〜２．０％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, the marine steel materials in any one of Claims 1-3 containing Mo: 0.01-5.0% and / or W: 0.01-2.0%.

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１〜４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 4 above.