JP3439588B2 - Highly efficient cathodic protection method - Google Patents
Highly efficient cathodic protection methodInfo
- Publication number
- JP3439588B2 JP3439588B2 JP34178095A JP34178095A JP3439588B2 JP 3439588 B2 JP3439588 B2 JP 3439588B2 JP 34178095 A JP34178095 A JP 34178095A JP 34178095 A JP34178095 A JP 34178095A JP 3439588 B2 JP3439588 B2 JP 3439588B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel
- cathodic protection
- protection method
- alkali
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Prevention Of Electric Corrosion (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は主として海洋環境で
使用される溶接鋼構造物の防食方法に関するものであ
る。さらに詳しくは、その防食方法の中のカソード電気
防食方法に関するもので、カソード防食時の電流値を低
減させる技術に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing corrosion of a welded steel structure used mainly in a marine environment. More specifically, it relates to a cathodic electrocorrosion method among the anticorrosion methods, and to a technique for reducing the current value during cathodic protection.
【0002】[0002]
【従来の技術】海洋環境で使用される鋼構造物のカソー
ド防食法は、極めて一般的な方法であり、たとえば、木
島茂著「防食工学」日刊工業新聞社昭和57年に詳しく
記載されている。カソード防食には大きく2種類の方法
があり、一つは外部電源方式で、もう一つは、流電陽極
方式である。外部電源方式では、鋼材の対極として金属
電極を鋼材と相対する位置に配置する。そして、直流電
源を用意し、防食される鋼材をマイナス側に、金属電極
をプラス側に接続し、両者の間に電流を流すことで防食
を行う。この際の電流値は、防食される鋼材の電位を制
御するために任意に設定される。2. Description of the Related Art The cathodic protection method for steel structures used in the marine environment is a very general method, and is described in detail in "Corrosion Engineering" by Shigeru Kijima, Nikkan Kogyo Shimbun, 1982. . There are roughly two types of methods for cathodic protection, one is an external power supply method and the other is a galvanic anode method. In the external power supply method, a metal electrode is arranged as a counter electrode of steel material at a position facing the steel material. Then, a DC power source is prepared, the steel material to be protected against corrosion is connected to the negative side, the metal electrode is connected to the positive side, and a current is passed between the two to prevent corrosion. The current value at this time is arbitrarily set in order to control the potential of the steel material to be protected against corrosion.
【0003】流電陽極方式では、対極として、ZnやA
lが使用される。これらの金属は、海水中で、鋼材より
も溶解しやすい卑な電位を持ち、これらの金属が溶解す
ることにより、電流を発生し、鋼材を防食する。この際
に、これらの金属をより解けやすくすることが、防食性
能を向上させることになり、たとえば、特開平4−15
7126号公報には、Al合金をもっと解けやすくし、
発生電流量を大きくした合金が開示されている。In the galvanic anode method, Zn or A is used as a counter electrode.
l is used. These metals have a base electric potential that is easier to dissolve in seawater than steel materials, and when these metals are dissolved, an electric current is generated to prevent corrosion of the steel materials. At this time, making these metals easier to dissolve improves the anticorrosion performance.
Japanese Patent No. 7126 discloses that an Al alloy is more easily melted,
An alloy having a large amount of generated current is disclosed.
【0004】[0004]
【発明が解決しようとする課題】カソード防食に関し、
長期にわたり鋼材を防食するための電流を流し続けるた
めに、外部電源方式では、電力コストがかさみ、かつエ
ネルギーを消費し続けることになる。また、流電陽極方
式では、金属電極が消耗してしまい、頻繁に取り替えね
ばならないという問題が存在している。この電極の交換
は、海中部での溶接作業を伴うために作業に多大の費用
を要するとともに、電極材料のAlやZn金属のコスト
もかさみ、かつ、工業生産品であるこれらの金属の浪費
にもつながる。このために、長期に渡り、防食に要する
電流量を低減させる技術が望まれていた。本発明は海水
中で溶接鋼構造物をカソード防食する際の防食電流を著
しく小さくする高効率電気防食方式の提供を目的とす
る。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In order to keep the electric current flowing to prevent corrosion of the steel for a long period of time, the external power supply method increases the power cost and continues to consume energy. Further, in the galvanic anode method, there is a problem that the metal electrode is consumed and must be replaced frequently. This replacement of electrodes requires a great deal of work because it involves welding work in the sea, and the cost of the Al and Zn metals of the electrode material is also high, and the waste of these metals as industrial products is wasted. Is also connected. For this reason, a technique for reducing the amount of current required for anticorrosion has been desired for a long period of time. It is an object of the present invention to provide a high-efficiency cathodic protection system that significantly reduces the anticorrosion current when cathodically protecting a welded steel structure in seawater.
【0005】[0005]
【課題を解決するための手段】本発明では、長期に渡
り、防食に要する電流量を低減させる方法として、鋼材
の成分と塗装処理を組み合わせて用いる。発明者らは、
鋼材の成分と塗装処理とを種々組み合わせて検討した結
果、含クロム鋼を鋼材とし、その上に耐アルカリ性に優
れた塗料で塗装することにより、長期に渡り、防食に要
する電流量を低減させ得ることを見つけだした。本発明
は、上記知見に基ずくものであって、溶接鋼構造物の下
地母材を含クロム鋼とし、この上に耐アルカリ性塗料を
塗布して、カソード電気防食することを特徴とする高効
率電気防食方法である。In the present invention, as a method for reducing the amount of current required for corrosion prevention for a long period of time, a combination of steel material components and coating treatment is used. The inventors
As a result of investigating various combinations of steel components and coating treatment, it is possible to reduce the amount of current required for corrosion protection over a long period of time by coating chromium-containing steel as a steel material and coating it with a coating with excellent alkali resistance. I found a thing. The present invention is based on the above findings, and is a high efficiency characterized by using a chromium-containing steel as a base base material of a welded steel structure, and applying an alkali-resistant coating on this to perform cathodic corrosion protection. It is an anticorrosion method.
【0006】(1) 重量%で、
C :0.01%以上、0.20%以下、
Si:0.01%以上、1.0%以下、
Mn:0.1%以上、2.5%以下、
P :0.020%以下、
S :0.020%以下、
Cr:0.3%以上、0.8%未満、
Al:0.002%以上、2.5%以下、
を含有し、残部Feおよび不可避的不純物からなる含ク
ロム鋼を鋼構造物の下地母材とし、この上に耐アルカリ
性塗料を塗布して、カソード電気防食することを特徴と
する高効率電気防食方法。(2)
上記含クロム鋼が、重量%で、
Ni:0.1%以上、0.5%未満
を含有することを特徴とする前記(1)記載の高効率電
気防食法。 (1) In % by weight, C: 0.01% or more and 0.20% or less, Si: 0.01% or more, 1.0% or less, Mn: 0.1% or more, 2.5% The following are included: P: 0.020% or less, S: 0.020% or less, Cr: 0.3% or more, less than 0.8%, Al: 0.002% or more, 2.5% or less, Containing Cu containing the balance Fe and unavoidable impurities
Rom steel is used as the base material of the steel structure, and alkali resistant
Characterized by applying a conductive paint to prevent cathodic corrosion
High-efficiency electric corrosion protection how to. (2) The high-efficiency cathodic protection method described in ( 1 ) above, wherein the chromium-containing steel contains, by weight%, Ni: 0.1% or more and less than 0.5%.
【0007】(3)上記含クロム鋼が、さらに、重量%
で、
Cu:0.05〜2.5%、
Mo:0.05〜4.5%、
Nb:0.005〜0.2%、
V :0.005〜0.2%、
Ti:0.005〜0.1%、
B :0.0003〜0.005%、
のいずれか1種または2種以上を含有することを特徴と
する前記(1)または(2)記載の高効率電気防食法。 (3) The above chromium-containing steel further comprises wt%.
Cu: 0.05 to 2.5%, Mo: 0.05 to 4.5%, Nb: 0.005 to 0.2%, V: 0.005 to 0.2%, Ti: 0. 005-0.1%, B: 0.0003-0.005%, any one kind or two or more kinds are contained, and the high-efficiency cathodic protection method according to (1) or (2) above is included. .
【0008】(4)上記含クロム鋼が、さらに、重量%
で、
Ca:0.001〜0.05%、
REM:0.001〜0.1%、
のいずれか1種または2種を含有することを特徴とする
前記(1)〜(3)記載の高効率電気防食法。(5)
上記耐アルカリ性塗料が、樹脂主成分としてエポ
キシ系樹脂または塩化ビニル系樹脂を含有し、耐アルカ
リ性顔料を0.1体積%以上含むことを特徴とする前記
(1)〜(4)記載の高効率電気防食方法。(6)
上記耐アルカリ性塗料が、10重量%苛性ソーダ
溶液中で、50℃、24時間浸漬した後の重量変化が1
%未満であることを特徴とする前記(1)〜(4)記載
の高効率電気防食方法である。 (4) The above chromium-containing steel further contains wt%.
And Ca: 0.001 to 0.05%, REM: 0.001 to 0.1%, and any one kind or two kinds of the above (1) to (3) is described. High efficiency cathodic protection. (5) The above-mentioned (1) to (4), wherein the alkali-resistant paint contains an epoxy resin or a vinyl chloride resin as a resin main component and contains an alkali-resistant pigment in an amount of 0.1% by volume or more. High-efficiency cathodic protection method. (6) The weight change of the above alkali-resistant coating after immersion in a 10 wt% caustic soda solution at 50 ° C. for 24 hours is 1
% Is less than%, which is the high-efficiency cathodic protection method described in (1) to (4) above.
【0009】[0009]
【発明の実施の形態】以下、本発明の限定理由について
説明する。本発明の電気防食方法では、含クロム鋼を鋼
材下地として耐アルカリ性塗料をその上に塗布する。こ
の組み合わせによって、電気防食を高効率化して、防食
電流の著しい低減を可能とする。この現象を、詳細に解
析した結果、耐アルカリ性塗膜のピンホール部で流れる
カソード電流はピンホール部を強いアルカリ性の雰囲気
にし、このアルカリ性雰囲気により、ピンホール部の含
クロム鋼の表面にクロム水酸化物の皮膜を形成すること
を見つけた。このクロム水酸化物の効果により、カソー
ド電流を低減させることがわかった。しかしながら、こ
の効果は、塗膜が強いアルカリ性の雰囲気で変質しない
ことが必要であり、塗料の性質との組み合わせが必須で
あることが分かった。BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limitation of the present invention will be described below. In the cathodic protection method of the present invention, a chromium-containing steel is used as a steel substrate and an alkali-resistant coating is applied thereon. By this combination, the efficiency of cathodic protection can be improved and the anticorrosion current can be remarkably reduced. As a result of a detailed analysis of this phenomenon, the cathode current flowing in the pinhole part of the alkali resistant coating creates a strong alkaline atmosphere in the pinhole part, and this alkaline atmosphere causes the chrome water on the surface of the chromium-containing steel in the pinhole part. It was found to form an oxide film. It was found that the effect of this chromium hydroxide reduces the cathode current. However, this effect requires that the coating film does not deteriorate in a strong alkaline atmosphere, and it has been found that a combination with the properties of the coating material is essential.
【0010】まず、本発明における下地鋼材としての含
クロム鋼の鋼成分を以下のように規定する。なお、以下
に用いる%は重量%を意味する。Cは安価に強度を上昇
させる元素であり、強度確保のため0.01%以上必要
であるが、多量に添加するとクロム酸化物の安定性を阻
害すると同時に、鋼の靱性、溶接性を害するので上限を
0.20%とした。Siは脱酸材として重要であるた
め、0.01%以上添加する必要があるが、1.0%を
超えて添加するとクロム酸化物の安定性を阻害すると同
時に、鋼の靱性、溶接性を害するので上限を1.0%と
した。First, the steel composition of the chromium-containing steel as the base steel material in the present invention is specified as follows. In addition,% used below means weight%. C is an element that raises the strength at a low cost, and 0.01% or more is necessary to secure the strength, but if added in a large amount, it impairs the stability of chromium oxide and at the same time impairs the toughness and weldability of steel. The upper limit was 0.20%. Since Si is important as a deoxidizing agent, it is necessary to add it in an amount of 0.01% or more. However, if it exceeds 1.0%, the stability of chromium oxide is impaired, and at the same time, the toughness and weldability of steel are improved. The upper limit was set to 1.0% because it causes harm.
【0011】Mnは固溶体強化元素であり、強度確保の
ため最低0.1%を添加する必要があるが、2.5%を
超えて添加するとクロム酸化物の安定性を阻害すると同
時に、鋼の靱性、溶接性を害するので上限を2.5%と
した。P、Sは鋼中において非金属介在物を形成し、か
つ、偏析することによりクロム酸化物の安定性を阻害す
ると同時に、鋼の靱性、溶接性を害するのでそれぞれ上
限を0.020%とした。P,Sともに、できれば0.
010%以下、さらに好ましくは0.005%以下がよ
い。Mn is a solid solution strengthening element, and it is necessary to add at least 0.1% in order to secure the strength. However, if it exceeds 2.5%, the stability of chromium oxide is impaired and at the same time the steel Since the toughness and weldability are impaired, the upper limit was made 2.5%. P and S form non-metallic inclusions in the steel and segregate to impair the stability of chromium oxide, and at the same time impair the toughness and weldability of the steel, so the upper limits were made 0.020% respectively. . Both P and S are preferably 0.
It is preferably 010% or less, more preferably 0.005% or less.
【0012】Crはカソード電流を低減させるクロム酸
水酸化物の皮膜を形成するのに不可欠な元素であり、
0.3%以上添加する必要がある。ただし、0.8%を
超えて添加すると溶接性、特に、大入熱溶接継手靱性を
損なうため、上限を0.8%未満とする。AlはSiと
同様に脱酸材として重要であるほか、靱性を向上させる
ため0.002%以上必要であるが、2.5%を超えて
添加するとクロム酸化物の安定性を阻害すると同時に、
鋼の靱性、溶接性を害するので上限を2.5%とした。
Niはクロム酸化物の安定性を向上させる重要な元素で
あり、必要により0.1%以上添加する。ただし、0.
5%を超えて添加すると溶接性、特に、大入熱溶接継手
靱性を損なうため、上限を0.5%未満とする。[0012] Cr is an essential element for forming a film of chromic acid hydroxide which reduces the cathode current,
It is necessary to add 0.3% or more. However, if added in excess of 0.8%, the weldability, particularly the toughness of large heat input welded joint, is impaired, so the upper limit is made less than 0.8%. Al, like Si, is important as a deoxidizing agent, and is required to be 0.002% or more to improve toughness, but if added in excess of 2.5%, it hinders the stability of chromium oxide and
The upper limit was set to 2.5% because it impairs the toughness and weldability of steel.
Ni is an important element that improves the stability of chromium oxide, and if necessary, 0.1% or more is added. However, 0.
If added in excess of 5%, the weldability, especially the toughness of large heat input welded joint, is impaired, so the upper limit is made less than 0.5%.
【0013】さらに、必要に応じてCu,Mo,Nb,
V,Ti,Bのいずれか1種または2種以上を添加す
る。これらは、すべて強度上昇に有効な元素であり、そ
の効果が不足しない範囲として、Cuは0.05%,M
oは0.05%,Nbは0.005%,Vは0.005
%,Tiは0.005%,Bは0.0003%を下限と
する。また靱性が低下しない範囲として、Cuは2.5
%,Moは4.5%,Nbは0.2%,Vは0.2%,
Tiは0.1%,Bは0.005%を上限とする。さら
に、必要に応じてCa,REMのいずれか1種または2
種を添加する。Ca,REMは靱性向上に有効な元素で
あり、その効果が不足しない範囲としてそれぞれの下限
をともに0.001%とし、また靱性がむしろ低下しな
い範囲として、Caは0.05%,REMは0.1%を
上限とする。Further, if necessary, Cu, Mo, Nb,
One or more of V, Ti and B are added. All of these are effective elements for increasing the strength, and Cu is 0.05%, M
o is 0.05%, Nb is 0.005%, V is 0.005
%, Ti is 0.005% and B is 0.0003%. Cu is 2.5 as a range in which the toughness does not decrease.
%, Mo 4.5%, Nb 0.2%, V 0.2%,
The upper limit of Ti is 0.1% and the upper limit of B is 0.005%. Further, if necessary, one or two of Ca and REM.
Add seeds. Ca and REM are effective elements for improving the toughness, and the lower limit of each is set to 0.001% as a range in which the effect is not insufficient, and Ca is 0.05% and REM is 0 as a range in which the toughness is not deteriorated. The upper limit is 1%.
【0014】上記含クロム鋼の製造条件については、鋼
塊または連続鋳造スラブを加熱後、熱間圧延を行い圧延
まま、または巻取りままで製品にする。また、必要に応
じて、その後に適当な熱処理を加えてもよい。主に厚
板、熱延鋼板として、板厚としては、2.0mmから5
0mm程度であるが、さらに薄手のもの、厚手のものも
使用が可能である。その他、品種として、形鋼、線・棒
鋼、鋼管等としても使用が可能である。Regarding the production conditions of the above chromium-containing steel, after the steel ingot or the continuously cast slab is heated, it is hot-rolled and rolled or rolled into a product. If necessary, appropriate heat treatment may be added thereafter. Mainly for thick plates and hot rolled steel plates, the plate thickness is from 2.0 mm to 5
Although it is about 0 mm, thinner and thicker ones can be used. In addition, it can be used as shaped steel, wire / bar steel, steel pipe, and the like.
【0015】次に、上記含クロム鋼の上に塗布する塗料
について述べる。本発明で適用する塗料は、塗膜のピン
ホール部を強いアルカリ性の雰囲気にして、ピンホール
の拡大を防止する機能を有することが必要である。その
ために、塗料には耐アルカリ性顔料を0.1体積%以上
含ませる。0.1体積%未満ではピンホール部の保護効
果が不十分である。一方、上限については特に制約はな
いが、通常は50体積%以下が適切である。Next, the paint applied on the chromium-containing steel will be described. The coating material applied in the present invention is required to have a function of preventing the pinhole from expanding by making the pinhole portion of the coating film have a strong alkaline atmosphere. Therefore, the coating contains an alkali resistant pigment in an amount of 0.1% by volume or more. If it is less than 0.1% by volume, the effect of protecting the pinhole portion is insufficient. On the other hand, the upper limit is not particularly limited, but usually 50 volume% or less is suitable.
【0016】耐アルカリ性顔料としては、アルカリでの
流出量の少ない化合物顔料、例えば、チタン酸塩,メタ
リン酸塩,バナジン酸塩等を挙げることができる。そし
て、塗料用のベース樹脂としては、エポキシ系及び変性
エポキシ系樹脂または塩化ビニル系樹脂を適用すること
が樹脂を耐アルカリ性の雰囲気とする点から好ましい。
ベースの樹脂を耐アルカリ性の弱いフタル酸系や鉱物油
系の樹脂を用いると、ピンホール部での剥離が大きくな
り、本発明の効果が得られない。また、これらの樹脂以
外であっても、10重量%の苛性ソーダ溶液中で、50
℃において24時間浸漬試験を行い、その時の重量変化
が1%未満である場合には、電気防食を行った際の塗膜
のピンホール部の剥離を小さくできる。Examples of alkali-resistant pigments include compound pigments which have a small outflow amount in alkali, such as titanates, metaphosphates, vanadates and the like. Then, as the base resin for the paint, it is preferable to apply an epoxy-based resin, a modified epoxy-based resin, or a vinyl chloride-based resin from the viewpoint of making the resin have an alkali-resistant atmosphere.
If a phthalic acid-based resin or a mineral oil-based resin having weak alkali resistance is used as the base resin, peeling at the pinhole portion becomes large, and the effect of the present invention cannot be obtained. Moreover, even if other than these resins, in a 10 wt% caustic soda solution,
When the immersion test is performed at 24 ° C. for 24 hours and the weight change at that time is less than 1%, the peeling of the pinhole portion of the coating film at the time of performing cathodic protection can be reduced.
【0017】[0017]
実施例1
表1に示した供試鋼を下地鋼板(寸法200mm×20
0mm)として、サンドブラスト処理を行い、純エポキ
シ樹脂系塗料に耐アルカリ顔料であるチタン酸バリウム
を表2に示す量添加した塗料を100μm塗布し、試験
材の中央部に大きさ10mmφの欠陥をあけ、この試験
体にアルミニウムを陽極とし、40℃人工海水中で1ケ
月浸漬した。そして試験後のアルミニウム電極の消耗量
並びに塗膜剥離幅を調査した。アルミニウムの消耗量は
電極の重量変化で、また、塗膜の剥離幅は中央部にあけ
た穴の拡大幅の平均値で求めた。なお、引張試験、0℃
でのシャルピー吸収エネルギーについても調査した。さ
らに、溶接効率の向上を目的としたSAW大入熱溶接
(入熱100kJ/cm)溶接継手の0℃でのシャルピ
ー吸収エネルギーについても調査した。ただし、板厚が
6mm未満のものは入熱50kJ/cmとした。それら
の調査結果を表2にまとめて示す。Example 1 The test steel shown in Table 1 was used as a base steel sheet (dimensions of 200 mm × 20).
(0 mm), sand blasting treatment was applied, and 100 μm of a paint containing barium titanate which is an alkali resistant pigment added in an amount shown in Table 2 was applied to a pure epoxy resin paint, and a defect with a size of 10 mmφ was opened in the center of the test material. Aluminum was used as an anode for this test body and immersed in artificial seawater at 40 ° C. for one month. Then, the amount of wear of the aluminum electrode and the peeling width of the coating film after the test were investigated. The amount of aluminum consumed was determined by the change in the weight of the electrode, and the peeling width of the coating film was determined by the average value of the expansion width of the hole formed in the center. In addition, tensile test, 0 ℃
We also investigated the Charpy absorbed energy. Furthermore, the Charpy absorbed energy at 0 ° C. of the SAW large heat input welding (heat input 100 kJ / cm) welded joint for the purpose of improving the welding efficiency was also investigated. However, if the plate thickness is less than 6 mm, the heat input was 50 kJ / cm. The survey results are summarized in Table 2.
【0018】[0018]
【表1】 [Table 1]
【0019】表1に示す鋼のうち鋼A〜Eは本発明の成
分範囲の鋼であり、鋼F〜Nは本発明外の比較鋼であ
る。これらの鋼を1250℃加熱した後に、900℃以
上で熱間圧延した。なお、板厚が25mm以上のものは
圧延後に焼きならし熱処理を行った。板厚が6mm未満
のものは圧延後600℃で巻取った。なお、鋼Nは通常
の普通鋼材を比較材として用いた。Among the steels shown in Table 1, steels A to E are steels in the composition range of the present invention, and steels F to N are comparative steels other than the present invention. After heating these steels at 1250 ° C, they were hot-rolled at 900 ° C or higher. For plates having a thickness of 25 mm or more, normalizing heat treatment was performed after rolling. Those having a plate thickness of less than 6 mm were rolled at 600 ° C. after rolling. As the steel N, a normal ordinary steel material was used as a comparative material.
【0020】[0020]
【表2】 [Table 2]
【0021】表2において、No.1〜9は本発明例で
あり、No.10〜19は比較例である。No.1,
3,5,6〜9,10,12〜13,18,19は板厚
が18mm、No.4,11,14〜17,20は板厚
が32mm、No.2は板厚4mmである。No.20
は通常の鋼材で耐アルカリ顔料が添加されていない場合
であって、これを比較として本発明の効果を検討した。
表2より明らかなように、No.1は塗膜剥離量、アル
ミ消耗量ともにNo.20に比べて半分以下に減少して
いる。No.2は、さらにNiを添加した鋼材を適用し
た場合であり、アルミ消耗量がNo.1よりもさらに減
少している。In Table 2, No. Nos. 1 to 9 are examples of the present invention. 10 to 19 are comparative examples. No. 1,
Nos. 3, 5, 6 to 9, 10, 12 to 13, 18, and 19 have a plate thickness of 18 mm, and No. Nos. 4, 11, 14 to 17 and 20 have a plate thickness of 32 mm, and No. 2 has a plate thickness of 4 mm. No. 20
Is a case in which an alkali resistant pigment is not added in a normal steel material, and the effect of the present invention was examined by comparing this with a case.
As is clear from Table 2, No. No. 1 is No. 1 for both the amount of paint peeling and the amount of aluminum consumption. It is less than half compared to 20. No. No. 2 is a case where a steel material to which Ni is further added is applied, and the aluminum consumption amount is No. 2. It is even lower than 1.
【0022】No.1〜6,10,11は耐アルカリ顔
料の添加効果を検討したものであり、耐アルカリ顔料の
添加量とともに塗膜剥離幅が減少し、かつアルミニウム
消費量も減少しているのがわかる。No.7は強度上昇
に有効な選択元素(Cu,Mo,Nb,V,B)を含有
するため、さらに高強度(≧500MPa)で塗膜剥離
量、アルミ消耗量とも減少している。No.8,9は靱
性上昇に有効な選択元素(Ca,またはREM)を含有
するため、さらに高靱性(≧100J)で塗膜剥離量、
アルミ消耗量とも減少している。No. Nos. 1 to 6, 10 and 11 are for studying the effect of addition of the alkali resistant pigment, and it can be seen that the coating peeling width decreases and the aluminum consumption also decreases with the addition amount of the alkali resistant pigment. No. Since No. 7 contains selective elements (Cu, Mo, Nb, V, B) effective for increasing the strength, the coating stripping amount and the aluminum consumption amount are further reduced at higher strength (≧ 500 MPa). No. Since Nos. 8 and 9 contain a selective element (Ca or REM) effective for increasing the toughness, the toughness (≧ 100 J) is further increased, and the amount of coating film peeling,
Aluminum consumption is also decreasing.
【0023】これに対して、比較例のNo.12はCが
高く、No.13はSiが高く、No.14はMnが高
く、No.15はPが高く、No.16はSが高く、そ
れぞれ塗膜剥離量、アルミ消耗量の減少は起こらず、同
時に靱性が低い。No.17はCr量が少なくて塗膜剥
離量、アルミ消耗量の減少は起こっていない。No.1
8,19はCr,Niが高く、継手シャルピーが低い。On the other hand, in Comparative Example No. No. 12 has a high C, and No. 12 No. 13 has a high Si, and No. No. 14 has a high Mn, and No. 14 No. 15 has a high P, and No. 16 has a high S, does not cause a reduction in the amount of coating film peeling and the amount of aluminum consumed, and at the same time has low toughness. No. In No. 17, the amount of Cr was small and the amount of coating film peeling and the amount of aluminum consumption were not reduced. No. 1
8 and 19 have high Cr and Ni and low joint Charpy.
【0024】実施例2
次に、塗装系を変えて行った試験結果について表3に示
す。表1の試験材A、Nを用い、試験法は実施例1と同
じである。鋼材No.Aを用いた場合に、耐アルカリ性
に優れる塗料を適用したNo.21,23,25は、本
発明の効果が認められたが、No.26,27のように
耐アルカリ性が劣る塗料を用いた場合には効果が得られ
ない。また、耐アルカリ性の高い塗料を用いても、鋼材
成分が本発明外の場合にはNo.22,24のように本
発明の目的とする効果が得られない。Example 2 Next, Table 3 shows the test results obtained by changing the coating system. The test materials A and N shown in Table 1 were used, and the test method was the same as in Example 1. Steel material No. When A was used, No. A to which a coating having excellent alkali resistance was applied was used. Nos. 21, 23, and 25 have the effects of the present invention, but No. No effect can be obtained when a coating having poor alkali resistance such as 26 or 27 is used. Even if a coating having a high alkali resistance is used, if the steel material component is outside the scope of the present invention, No. 22 and 24, the desired effect of the present invention cannot be obtained.
【0025】[0025]
【表3】 [Table 3]
【0026】実施例3
表4に示す鋼材で、100mm×2500mmの短冊状
の試験片を作製し、Zn陽極を取り付け、北九州市の海
岸に3年間浸漬暴露試験を行った。引き上げ後、Znア
ノードの消耗量を計測した結果を、表4に合わせて示
す。本発明例のNo.28〜30およびNo.32〜3
4は、比較例のNo.31,35と比較してZnの消耗
量が極めて少ないことが明瞭に分かる。Example 3 A strip-shaped test piece of 100 mm × 2500 mm was prepared from the steel material shown in Table 4, a Zn anode was attached, and a dip exposure test was conducted on the coast of Kitakyushu for 3 years. The results of measuring the amount of consumption of the Zn anode after the pulling up are also shown in Table 4. No. 1 of the present invention example. 28-30 and No. 32-3
No. 4 of the comparative example. It can be clearly seen that the consumption amount of Zn is extremely small as compared with 31 and 35.
【0027】[0027]
【表4】 [Table 4]
【0028】[0028]
【発明の効果】本発明の方法によれば、鋼構造物等の母
材成分とその上に塗布する塗料との組み合わせを特定化
することによって、海洋環境下での電気防食の寿命を約
2倍に長持ちさせることが可能になる。この結果、海洋
鋼構造物のメンテナンスコストを下げることが可能にな
り、また、アルミニウムや亜鉛などの使用量を減少させ
ることが出来、環境への負担も軽減できることになる。According to the method of the present invention, the life of cathodic protection in a marine environment is about 2 by specifying the combination of the base material component of the steel structure and the coating material to be applied thereon. It becomes possible to make it last twice as long. As a result, the maintenance cost of the offshore steel structure can be reduced, the amount of aluminum and zinc used can be reduced, and the burden on the environment can be reduced.
フロントページの続き (72)発明者 松岡 和巳 千葉県富津市新富20−1 新日本製鐵株 式会社 技術開発本部内 (56)参考文献 特開 平9−143766(JP,A) (58)調査した分野(Int.Cl.7,DB名) C22C 38/00 301 C22C 38/38 C22C 38/58 C23F 11/00 C23F 13/00 Continuation of the front page (72) Inventor Kazumi Matsuoka 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Co., Ltd. Technology Development Division (56) References JP-A-9-143766 (JP, A) (58) Survey Fields (Int.Cl. 7 , DB name) C22C 38/00 301 C22C 38/38 C22C 38/58 C23F 11/00 C23F 13/00
Claims (6)
ロム鋼を鋼構造物の下地母材とし、 この上に耐アルカリ
性塗料を塗布して、カソード電気防食することを特徴と
する高効率電気防食方法。1. In % by weight, C: 0.01% or more and 0.20% or less, Si: 0.01% or more, 1.0% or less, Mn: 0.1% or more, 2.5% or less. , P: 0.020% or less, S: 0.020% or less, Cr: 0.3% or more, less than 0.8%, Al: 0.002% or more, 2.5% or less, and the balance Cu containing Fe and unavoidable impurities
A high-efficiency cathodic protection method, characterized in that ROM steel is used as a base material for a steel structure, and an alkali-resistant paint is applied on this to cathodic cathodic protection.
防食法。2. The high-efficiency cathodic protection method according to claim 1, wherein the chromium-containing steel contains , by weight%, Ni: 0.1% or more and less than 0.5% .
する請求項1または2記載の高効率電気防食法。3. The chromium-containing steel further comprises, by weight, Cu: 0.05 to 2.5%, Mo: 0.05 to 4.5%, Nb: 0.005 to 0.2%, V: 0.005 to 0.2%, Ti: 0.005 to 0.1%, B: 0.0003 to 0.005%, and any one kind or two or more kinds is contained. The high-efficiency cathodic protection method according to claim 1 .
請求項1〜3記載の高効率電気防食法。4. The chromium-containing steel further contains, in wt%, any one or two of Ca: 0.001 to 0.05 % and REM: 0.001 to 0.1%. efficient cathodic protection method according to claim 1-3, wherein a.
してエポキシ系樹脂または塩化ビニル系樹脂を含有し、
耐アルカリ性顔料を0.1体積%以上含むことを特徴と
する請求項1〜4記載の高効率電気防食方法。5. The alkali-resistant paint comprises a resin main component.
And contains epoxy resin or vinyl chloride resin,
It is characterized by containing 0.1% by volume or more of an alkali resistant pigment.
The high-efficiency cathodic protection method according to claim 1 .
性ソーダ溶液中で、50℃、24時間浸漬した後の重量
変化が1%未満であることを特徴とする請求項1〜4記
載の高効率電気防食方法。6. The alkali resistant coating composition comprises 10 wt% caustic.
Weight after soaking in a soda solution at 50 ° C for 24 hours
The change is less than 1%, and the high-efficiency cathodic protection method according to claim 1, wherein the change is less than 1% .
Priority Applications (1)
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JP34178095A JP3439588B2 (en) | 1995-12-27 | 1995-12-27 | Highly efficient cathodic protection method |
Applications Claiming Priority (1)
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JP34178095A JP3439588B2 (en) | 1995-12-27 | 1995-12-27 | Highly efficient cathodic protection method |
Publications (2)
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JPH09176791A JPH09176791A (en) | 1997-07-08 |
JP3439588B2 true JP3439588B2 (en) | 2003-08-25 |
Family
ID=18348708
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JP2006037201A (en) * | 2004-07-29 | 2006-02-09 | Kobe Steel Ltd | Marine steel material superior in corrosion resistance |
JP5265944B2 (en) * | 2008-03-04 | 2013-08-14 | 株式会社神戸製鋼所 | Marine steel with excellent corrosion resistance |
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