JP2013194314A - Steel material superior in corrosion resistance after coating - Google Patents
Steel material superior in corrosion resistance after coating Download PDFInfo
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- JP2013194314A JP2013194314A JP2012066277A JP2012066277A JP2013194314A JP 2013194314 A JP2013194314 A JP 2013194314A JP 2012066277 A JP2012066277 A JP 2012066277A JP 2012066277 A JP2012066277 A JP 2012066277A JP 2013194314 A JP2013194314 A JP 2013194314A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 55
- 239000010959 steel Substances 0.000 title claims abstract description 55
- 230000007797 corrosion Effects 0.000 title claims abstract description 42
- 238000005260 corrosion Methods 0.000 title claims abstract description 42
- 239000000463 material Substances 0.000 title claims abstract description 41
- 239000011248 coating agent Substances 0.000 title claims abstract description 37
- 238000000576 coating method Methods 0.000 title claims abstract description 37
- 229910052802 copper Inorganic materials 0.000 claims abstract description 15
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 14
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 230000007613 environmental effect Effects 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 6
- 229910052710 silicon Inorganic materials 0.000 abstract description 2
- 230000002708 enhancing effect Effects 0.000 abstract 1
- 230000014509 gene expression Effects 0.000 abstract 1
- 238000012360 testing method Methods 0.000 description 23
- 230000000694 effects Effects 0.000 description 18
- 230000008961 swelling Effects 0.000 description 18
- 238000000034 method Methods 0.000 description 10
- 239000003973 paint Substances 0.000 description 10
- 150000003839 salts Chemical class 0.000 description 10
- 238000001816 cooling Methods 0.000 description 7
- 238000005096 rolling process Methods 0.000 description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 238000004381 surface treatment Methods 0.000 description 4
- 239000003822 epoxy resin Substances 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000009849 vacuum degassing Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- Heat Treatment Of Steel (AREA)
Abstract
Description
本発明は、鋼構造物の防食に塗装やライニングなどの有機層を用いる場合に、塗膜の腐食劣化を効果的に抑制することができる塗装耐食性に優れた鋼材に関するものである。 The present invention relates to a steel material excellent in coating corrosion resistance that can effectively suppress corrosion deterioration of a coating film when an organic layer such as coating or lining is used for corrosion prevention of a steel structure.
近年、鋼構造物を防食する手法としての塗装の利用割合は50％を超えている。しかしながら、塗装の耐用年数は鋼構造物の耐用年数よりも寿命が短いため、鋼構造物を維持管理するためには、複数回の塗り替え塗装が必要になる。このため、これら鋼構造物の維持管理費用は、トータルで莫大な金額になる。
従って、塗装の寿命を延長させることができるならば、維持管理費用の低減に大きく貢献する。
In recent years, the proportion of paint used as a method for preventing corrosion of steel structures has exceeded 50%. However, since the service life of the coating is shorter than the service life of the steel structure, a plurality of repaints are required to maintain and manage the steel structure. For this reason, the total maintenance cost of these steel structures is enormous.
Therefore, if the coating life can be extended, it greatly contributes to a reduction in maintenance costs.
塗装塗り替え理由の中には、少なからず腐食に起因した塗装の劣化が認められる。そのため、塗装の耐久性を高めるための技術が種々提案されている。
例えば特許文献１には、耐侯性鋼をベースとして、リン酸系の表面処理を施すことによって塗装の寿命を延ばすこと記載されている。
特許文献２には、0.2〜0.7％Cu含有鋼についてリン酸系表面処理を施すことが示されている。
特許文献３には、Cu，NiおよびTiを含有させることによって、塗装の寿命を延長できることが示されている。
特許文献４には、Snイオンを含有する表面処理にてSn含有層を形成し、その上に塗装あるいはライニングを施す技術が開示されている。
Among the reasons for repainting, there is a considerable amount of paint deterioration due to corrosion. For this reason, various techniques for improving the durability of coating have been proposed.
For example, Patent Document 1 describes extending the life of the coating by applying phosphoric acid-based surface treatment based on weather resistant steel.
Patent Document 2 shows that 0.2 to 0.7% Cu-containing steel is subjected to phosphoric acid-based surface treatment.
Patent Document 3 shows that the life of the coating can be extended by containing Cu, Ni and Ti.
Patent Document 4 discloses a technique in which a Sn-containing layer is formed by a surface treatment containing Sn ions, and coating or lining is performed thereon.
上記した特許文献１〜４に開示された方法はいずれも、塗装耐久性に対して使用環境面からの配慮がなされておらず、いずれも同一の材料で効果を有するとしているが、全ての環境で優れた特性を発揮しない点に問題を残していた。また、特許文献１，２，４に記載の方法においては、鋼材のみならず表面処理を併用することから、施工面での制約が多く経済的に不利になる点が加えて問題となる。
塗装耐食性は、鋼材が置かれる環境によって、その劣化メカニズムや対処法も変化するので、同一材料で全ての環境をコントロールすることは極めて難しいことが大きな課題である。
None of the methods disclosed in Patent Documents 1 to 4 described above are considered to have an effect with the same material because no consideration is given to the durability of the coating from the viewpoint of the use environment. However, it left a problem in that it did not exhibit excellent characteristics. Moreover, in the method of patent document 1, 2, 4, since not only steel materials but surface treatment is used together, there are many restrictions on a construction surface and it becomes economically disadvantageous, and becomes a problem.
The corrosion resistance of coating is a major issue that it is extremely difficult to control all environments with the same material because the deterioration mechanism and countermeasures vary depending on the environment where the steel is placed.
本発明は、上記の現状に鑑み開発されたもので、鋼材そのものの耐食性を向上させるだけでなく、環境に応じて対応鋼種を変更することにより、塗装耐久性をあらゆる環境において延長させることができる塗装耐食性に優れた鋼材を提案することを目的とする。 The present invention has been developed in view of the above situation, and not only improves the corrosion resistance of the steel itself, but also changes the corresponding steel type depending on the environment, thereby extending the coating durability in any environment. The purpose is to propose a steel material with excellent paint corrosion resistance.
さて、発明者らは、上記の課題を解決すべく、塗装鋼材の腐食現象について鋭意研究を重ねた。
その結果、塗装鋼材の腐食劣化（長期間および短期間ともに）に対しては、主にＷ，Cuの添加が有効であること、そして使用環境に応じてＷとCuの比を調整することにより、幅広い使用環境にわたって優れた塗装耐食性を発揮できることの知見を得た。
本発明は、上記の知見に立脚するものである。
Now, in order to solve the above-mentioned problems, the inventors have conducted intensive research on the corrosion phenomenon of painted steel materials.
As a result, for corrosion deterioration (both long-term and short-term) of coated steel materials, the addition of W and Cu is mainly effective, and by adjusting the ratio of W and Cu according to the usage environment They have obtained knowledge that they can exhibit excellent paint corrosion resistance over a wide range of usage environments.
The present invention is based on the above findings.
すなわち、本発明の要旨構成は次のとおりである。
１．質量％で、
Ｃ：0.03〜0.3％、
Si：0.01〜1.0％、
Mn：0.1〜2.0％、
Ｐ：0.03％以下、
Ｓ：0.005％以下、
Ｗ：0.01％以上、0.10％未満および
Cu：0.01〜0.5％
を、ＷとCuの合計が0.3≦10Ｗ＋Cu≦1.0を満足する範囲で含有し、残部はFeおよび不可避的不純物からなり、図１に示す４つの環境区分（領域Ｉ、領域II、領域III、領域IV）に応じて、ＷとCuの質量比を、下記式で示す範囲に調整することを特徴とする塗装耐食性に優れた鋼材。
記
領域Ｉの時 0.1≦10Ｗ/Cu≦１
領域IIの時 ３≦10Ｗ/Cu≦30
領域IIIの時 １≦10Ｗ/Cu≦３
領域IVの時 ３≦10Ｗ/Cu≦30
That is, the gist configuration of the present invention is as follows.
1. % By mass
C: 0.03-0.3%,
Si: 0.01 to 1.0%
Mn: 0.1-2.0%
P: 0.03% or less,
S: 0.005% or less,
W: 0.01% or more, less than 0.10% and
Cu: 0.01-0.5%
In the range where the total of W and Cu satisfies 0.3 ≦ 10W + Cu ≦ 1.0, and the balance consists of Fe and inevitable impurities, and the four environmental categories (region I, region II, region III, region shown in FIG. According to IV), a steel material excellent in coating corrosion resistance, characterized in that the mass ratio of W and Cu is adjusted to a range represented by the following formula.
Record
In Region I 0.1 ≦ 10W / Cu ≦ 1
In Region II 3 ≦ 10W / Cu ≦ 30
In Region III 1 ≦ 10W / Cu ≦ 3
In Region IV 3 ≦ 10W / Cu ≦ 30
２．前記鋼材が、さらに質量％で、
Ge：0.005〜0.1％、
Sb：0.005〜0.1％、
Bi：0.005〜0.1％および
Se：0.005〜0.1％
のうちから選んだ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に記載の鋼材。
2. The steel material is further mass%,
Ge: 0.005-0.1%
Sb: 0.005 to 0.1%,
Bi: 0.005-0.1% and
Se: 0.005-0.1%
The steel material according to 1 above, containing one or more selected from among the above.
３．前記鋼材が、さらに質量％で、
Nb：0.005〜0.1％、
Ｖ：0.005〜0.1％および
Ti：0.005〜0.1％
のうちから選んだ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に記載の鋼材。
3. The steel material is further mass%,
Nb: 0.005 to 0.1%,
V: 0.005-0.1% and
Ti: 0.005-0.1%
The steel material according to 1 or 2 above, which contains one or more selected from among the above.
本発明によれば、建築・土木構造物用鋼材として使用し、表面に塗料による防食をした場合に、従来の鋼材に比べてより長期間にわたる使用が可能で、また腐食による塗り替えの削減や損傷による事故を回避することができる鋼材を、安価に得ることができ、産業上極めて有用である。 According to the present invention, when used as a steel material for construction and civil engineering structures, when the surface is anticorrosive with paint, it can be used for a longer period of time compared to conventional steel materials, and the repainting or damage due to corrosion It is possible to obtain a steel material that can avoid the accident caused by the above at a low cost, which is extremely useful industrially.
以下、本発明を具体的に説明する。
まず、本発明において鋼材の成分組成を前記の範囲に限定した理由について説明する。なお、鋼材の成分組成における元素の含有量の単位はいずれも「質量％」であるが、以下、特に断らない限り単に「％」で示す。
Hereinafter, the present invention will be specifically described.
First, the reason why the component composition of the steel material is limited to the above range in the present invention will be described. In addition, although the unit of element content in the component composition of steel materials is “mass%”, hereinafter, unless otherwise specified, it is simply indicated by “%”.
Ｃ：0.03〜0.3％
Ｃは、鋼の強度確保に必要な元素であり、本発明で目標とする強度（400MPa以上）を確保するためには少なくとも0.03％の含有が必要であり、一方0.3％を超えると溶接性が低下し、溶接の際に制限が加わるため、Ｃ量は0.03〜0.3％の範囲とする。
C: 0.03-0.3%
C is an element necessary for ensuring the strength of the steel, and in order to ensure the target strength (400 MPa or more) in the present invention, it is necessary to contain at least 0.03%. The amount of C is in the range of 0.03 to 0.3% because it decreases and limits are applied during welding.
Si：0.01〜1.0％
Siは、脱酸のため添加するが、含有量が0.01％未満では脱酸効果に乏しく、一方1.0％ を超えると靭性や溶接性を劣化させるため、Si量は0.01〜1.0％の範囲とする。
Si: 0.01-1.0%
Si is added for deoxidation, but if the content is less than 0.01%, the deoxidation effect is poor. On the other hand, if it exceeds 1.0%, the toughness and weldability are deteriorated, so the Si content is in the range of 0.01 to 1.0%. .
Mn：0.1〜2.0％
Mnは、強度、靭性を改善するために添加するが、0.1％未満ではその効果が十分でなく、一方2.0％を超えると溶接性が劣化するため、Mn量は0.1〜2.0％の範囲とする。
Mn: 0.1-2.0%
Mn is added to improve strength and toughness, but if it is less than 0.1%, the effect is not sufficient. On the other hand, if it exceeds 2.0%, the weldability deteriorates, so the Mn content is in the range of 0.1 to 2.0%. .
Ｐ：0.03％以下
Ｐは、不可避的不純物として含有されるが、靭性および溶接性を劣化させるため、Ｐ量は0.03％以下に抑制するものとした。
P: 0.03% or less P is contained as an inevitable impurity. However, in order to deteriorate toughness and weldability, the amount of P is suppressed to 0.03% or less.
Ｓ：0.005％以下
Ｓも、不可避的不純物として含有されるが、含有量が多くなると塗装耐食性が低下するだけでなく、MnＳなどの介在物が増加してSCCの起点となり塗装耐食性を低下させるので、極力低減することが望ましいが、0.005％以下であれば許容できる。
S: 0.005% or less S is also included as an inevitable impurity, but as the content increases, not only does the coating corrosion resistance decrease, but inclusions such as MnS increase, leading to SCC and lowering the coating corrosion resistance. It is desirable to reduce as much as possible, but 0.005% or less is acceptable.
Ｗ：0.01％以上、0.10％未満
Ｗは、腐食生成物として酸素酸塩を形成し、かかる腐食生成物が腐食抑制材として作用する。また、鋼材中にあっては、不均一腐食を低減する効果も併せ持っている。そのため塗装耐久性を改善する効果が発現する。特にＷは、湿潤率の高い環境に適した元素である。しかしながら、含有量が0.01％未満では塗装耐食性の改善効果に乏しく、一方0.10％以上ではコスト的に不利になるため、Ｗ量は0.01％以上、0.10％未満の範囲とする。より好ましくは0.03〜0.06％の範囲である。
W: 0.01% or more and less than 0.10% W forms an oxyacid salt as a corrosion product, and the corrosion product acts as a corrosion inhibitor. In steel, it also has the effect of reducing non-uniform corrosion. Therefore, the effect of improving the coating durability is manifested. In particular, W is an element suitable for an environment with a high wet rate. However, if the content is less than 0.01%, the effect of improving the coating corrosion resistance is poor. On the other hand, if the content is 0.10% or more, the cost is disadvantageous, so the W content is in the range of 0.01% or more and less than 0.10%. More preferably, it is 0.03 to 0.06% of range.
Cu：0.01〜0.5％
Cuは、長期間にわたって塗装耐食性の改善効果を維持する上で有効な元素である。特にCuは、湿潤率の高くない環境で有効な元素である。しかしながら、含有量が0.01％未満ではその効果に乏しく、一方0.5％を超えると鋼材製造上の面から制約が生じるので、Cu量は0.01〜0.5％の範囲とする。
Cu: 0.01-0.5%
Cu is an element effective in maintaining the effect of improving the coating corrosion resistance over a long period of time. In particular, Cu is an element effective in an environment where the wet rate is not high. However, if the content is less than 0.01%, the effect is poor. On the other hand, if the content exceeds 0.5%, there are restrictions in terms of steel production, so the Cu content is in the range of 0.01 to 0.5%.
ＷおよびCuについては、どちらも同様な効果を有する元素であるが、その配合量も重要である。
そこで、発明者らは、ＷとCuを複合含有させる時の好適合計量について検討した結果、合計量を（10Ｗ＋Cu）で規定して、0.3≦10Ｗ＋Cu≦1.0（％）を満足する範囲で含有させる必要があることが判明した。
すなわち、CuとＷの合計量が（10Ｗ＋Cu）で0.3％に満たないと十分に塗装の寿命を延長する効果が得られず、一方1.0を超えると効果は飽和に達し、むしろ経済的に不利となるためである。
W and Cu are both elements having the same effect, but the blending amount is also important.
Therefore, the inventors have studied the preferred total amount when W and Cu are contained in a composite manner. As a result, the total amount is defined as (10W + Cu), and is included in a range satisfying 0.3 ≦ 10W + Cu ≦ 1.0 (%). It turns out that there is a need.
In other words, if the total amount of Cu and W is less than 0.3% at (10W + Cu), the effect of extending the life of the coating will not be obtained sufficiently, while if it exceeds 1.0, the effect will reach saturation, rather economically disadvantageous. It is to become.
ところで、本発明の鋼材は、使用環境の違いに応じて、成分とくにＷとCuの質量比を的確に調整することにより、各環境に応じて適切な塗装耐食性を発揮させることができる。
環境区分としては、次に定義する湿潤率（Wet率）と飛来塩分量により、図１に示すように、領域Ｉ、領域II、領域IIIおよび領域IVの４つの領域に区分する。
ここに、湿潤率（Wet率）は、例えば表１に示すように、使用環境近傍で計測された年平均相対湿度（RH）と年平均気温（T）から導出した、湿度に関する確率係数Ｐ(RH)と温度に関する確率係数Ｐ(T)を用いて、次式により算出する。
Wet率＝Ｐ(RH)×Ｐ(T)
そして、この湿潤率（Wet率）：50％を境界として区分する。なお、明らかに制御された環境においては、相対湿度：80％RH以上や、没水、噴霧などの濡れ時間を対象として計算する。
また、飛来塩分量は10mddを境界とする。
By the way, the steel material of this invention can exhibit suitable coating corrosion resistance according to each environment by adjusting the mass ratio of a component especially W and Cu according to the difference in use environment.
As shown in FIG. 1, the environment is divided into four regions, region I, region II, region III, and region IV, based on the wet rate (wet rate) and the amount of incoming salt as defined below.
Here, as shown in Table 1, for example, the wetness rate (Wet rate) is a probability coefficient P (related to humidity derived from the annual average relative humidity (RH) and the annual average temperature (T) measured in the vicinity of the use environment. RH) and a probability coefficient P (T) related to temperature are calculated by the following equation.
Wet rate = P (RH) x P (T)
Then, this wetness rate (Wet rate): 50% is used as a boundary. In a clearly controlled environment, the relative humidity is calculated to be 80% RH or more, and the wet time such as submerged or sprayed.
The amount of incoming salt is 10mdd.
そして、上記のようにして区分した領域毎に、（10Ｗ/Cu）で規定したＷとCuの質量比を下記式で示す範囲に調整することによって、各領域すなわち各使用環境における塗装耐食性の一層の向上を図ることができる。
記
領域Ｉの時 0.1≦10Ｗ/Cu≦１
領域IIの時 ３≦10Ｗ/Cu≦30
領域IIIの時 １≦10Ｗ/Cu≦３
領域IVの時 ３≦10Ｗ/Cu≦30
And by adjusting the mass ratio of W and Cu defined by (10 W / Cu) to the range shown by the following formula for each area divided as described above, the coating corrosion resistance in each area, that is, in each use environment is further increased. Can be improved.
Record
In Region I 0.1 ≦ 10W / Cu ≦ 1
In Region II 3 ≦ 10W / Cu ≦ 30
In Region III 1 ≦ 10W / Cu ≦ 3
In Region IV 3 ≦ 10W / Cu ≦ 30
以上、基本成分について説明したが、本発明では、その他にも、以下に述べる元素を必要に応じて適宜含有させることができる。
Ge：0.005〜0.1％、Sb：0.005〜0.1％、Bi：0.005〜0.1％およびSe：0.005〜0.1％のうちから選んだ１種または２種以上
Ge，Sb，BiおよびSeはいずれも、塗装耐食性の一層の向上を図る上で有用な元素である。また、これらの元素は、弱酸性環境における塗装耐食性の改善にも有効に寄与する。ここに、Ge量が0.005％未満では塗装耐食性の改善効果に乏しく、一方0.1％超ではコスト的な不利を招く。Sb量が0.005％未満では塗装耐食性の改善効果に乏しく、一方0.1％超では鋼材の機械的特性の低下を招く。Se量が0.005％未満では塗装耐食性の改善効果に乏しく、一方0.1％超ではコスト的な不利を招く。Bi量が0.005％未満では塗装耐食性の改善効果に乏しく、一方0.1％超では鋼材の機械的特性の低下を招く。それ故、これらの元素は、単独添加または複合添加いずれの場合も0.005〜0.1％の範囲で含有させるものとする。
Although the basic components have been described above, in the present invention, other elements described below can be appropriately contained as necessary.
Ge: 0.005-0.1%, Sb: 0.005-0.1%, Bi: 0.005-0.1% and Se: One or more selected from 0.005-0.1%
Ge, Sb, Bi and Se are all useful elements for further improving the coating corrosion resistance. These elements also contribute effectively to improving the coating corrosion resistance in a weakly acidic environment. Here, if the Ge amount is less than 0.005%, the effect of improving the coating corrosion resistance is poor, while if it exceeds 0.1%, a cost disadvantage is caused. If the Sb content is less than 0.005%, the effect of improving the coating corrosion resistance is poor, while if it exceeds 0.1%, the mechanical properties of the steel material are deteriorated. If the Se content is less than 0.005%, the effect of improving the coating corrosion resistance is poor, while if it exceeds 0.1%, a cost disadvantage is caused. If the amount of Bi is less than 0.005%, the effect of improving the coating corrosion resistance is poor, while if it exceeds 0.1%, the mechanical properties of the steel material are deteriorated. Therefore, these elements should be contained in the range of 0.005 to 0.1% in either case of single addition or composite addition.
Nb：0.005〜0.1％、Ｖ：0.005〜0.1％およびTi：0.005〜0.1％のうちから選んだ１種または２種以上
Nb，ＶおよびTiはいずれも、鋼材の機械的特性および塗装耐食性を向上させるために有用な元素である。これらの元素はいずれも、含有量が0.005％未満ではその添加効果に乏しく、一方0.1％を超えると溶接部の機械的特性が低下するので、単独添加または複合添加いずれの場合も0.005〜0.1％の範囲で含有させるものとする。
One or more selected from Nb: 0.005-0.1%, V: 0.005-0.1% and Ti: 0.005-0.1%
Nb, V and Ti are all useful elements for improving the mechanical properties and paint corrosion resistance of steel. Any of these elements has a poor effect of addition when the content is less than 0.005%, whereas when it exceeds 0.1%, the mechanical properties of the weld deteriorate, so 0.005 to 0.1% in either case of single addition or compound addition It shall be contained in the range of.
さらに、本発明の効果を損なわない範囲内であれば、上記以外の元素の含有を拒むものではない。例えば、上記した元素の他に、AlやREMを脱酸剤として少量に添加することもできる。
なお、本発明の鋼材において、上記以外の成分は、Feおよび不可避的不純物である。
Furthermore, the content of elements other than the above is not rejected as long as the effects of the present invention are not impaired. For example, in addition to the elements described above, Al or REM can be added in a small amount as a deoxidizer.
In addition, in the steel material of this invention, components other than the above are Fe and inevitable impurities.
次に、本発明鋼材の好適製造方法について説明する。
上記した好適成分組成になる溶鋼を、転炉や電気炉等の公知の炉で溶製し、連続鋳造法や造塊法等の公知の方法でスラブやビレット等の鋼素材とする。なお、溶製に際して、真空脱ガス精錬等を実施しても良い。
溶鋼の成分調整方法は、公知の鋼精錬方法に従えばよい。
Next, the suitable manufacturing method of this invention steel material is demonstrated.
The molten steel having the preferred component composition described above is melted in a known furnace such as a converter or an electric furnace, and is made into a steel material such as a slab or billet by a known method such as a continuous casting method or an ingot forming method. In addition, vacuum degassing refining or the like may be performed at the time of melting.
The component adjustment method of molten steel should just follow a well-known steel refining method.
ついで、上記の鋼素材を所望の寸法形状に熱間圧延する際には、1000〜1350℃の温度に加熱する。加熱温度が1000℃未満では変形抵抗が大きく、熱間圧延が難しくなる。一方、1350℃を超えると、表面痕の発生原因となったり、スケールロスや燃料原単位が増加したりする。好ましくは1050〜1300℃の範囲である。なお、鋼素材の温度が、もともと1000〜1350℃の範囲の場合には、加熱せずに、そのまま熱間圧延に供してもよい。
なお、熱間圧延では、熱間仕上圧延終了温度を適正化することが望ましく、600℃以上 850℃以下とすることが好ましい。熱間仕上圧延終了温度が600℃未満では、変形抵抗の増大により圧延荷重が増加し、圧延の実施が困難となる。一方、850℃超えだと所望の強度を得ることが難しくなる。熱間仕上圧延終了後の冷却は、空冷または冷却速度：150℃/ｓ以下の加速冷却とすることが好ましい。加速冷却する場合の冷却停止温度は300〜750℃の範囲とすることが好ましい。なお、冷却後、再加熱処理を施してもよい。
Next, when the steel material is hot-rolled to a desired size and shape, it is heated to a temperature of 1000 to 1350 ° C. When the heating temperature is less than 1000 ° C., the deformation resistance is large and hot rolling becomes difficult. On the other hand, if the temperature exceeds 1350 ° C, it may cause surface marks, increase scale loss and fuel consumption. Preferably it is the range of 1050-1300 degreeC. In addition, when the temperature of the steel material is originally in the range of 1000 to 1350 ° C., it may be subjected to hot rolling as it is without being heated.
In hot rolling, it is desirable to optimize the finish temperature of hot finish rolling, and it is preferable to set the temperature to 600 ° C. or higher and 850 ° C. or lower. When the finish temperature of hot finish rolling is less than 600 ° C., the rolling load increases due to an increase in deformation resistance, making it difficult to perform rolling. On the other hand, if it exceeds 850 ° C., it is difficult to obtain a desired strength. The cooling after the hot finish rolling is preferably air cooling or accelerated cooling with a cooling rate of 150 ° C./s or less. The cooling stop temperature for accelerated cooling is preferably in the range of 300 to 750 ° C. Note that, after cooling, reheating treatment may be performed.
次に、本発明の実施例について説明する。なお、本発明はこれらの実施例のみに限定されるものではない。
表２に示す成分組成になる溶鋼を、真空溶解炉で溶製後または転炉溶製後、連続鋳造によりスラブとした。ついで、1250℃に加熱後、仕上圧延終了温度：800℃の条件で熱間圧延を実施して、30mm厚の鋼材とした。
これらの鋼材について、次の塗装耐食性試験を実施した。
Next, examples of the present invention will be described. In addition, this invention is not limited only to these Examples.
The molten steel having the composition shown in Table 2 was made into a slab by continuous casting after melting in a vacuum melting furnace or after melting in a converter. Next, after heating to 1250 ° C., hot rolling was performed at a finish rolling finish temperature of 800 ° C. to obtain a steel material with a thickness of 30 mm.
The following coating corrosion resistance tests were conducted on these steel materials.
(ａ) エポキシ樹脂塗料による耐食試験材の作成
鋼材を、長さ：100mm、幅：75mm、厚さ：６mmに切り出し、両面をグリットブラスト（表面仕上げ ISO Sa 2.5）で仕上げ、アセトン中で超音波脱脂を５分間行い、風乾して塗装耐食性の供試材とし た。片面は塗装するための面とし、もう片面および端面は溶剤型のエポキシ樹脂塗料にてシールし、さらにシリコン系のシール剤にて被覆した。また、塗料として、エポキシ樹脂塗料（関西ペイント製 エポマリン）を、エアレススプレーにて、先のブラスト表面上に塗布した。塗装膜厚は、乾燥後の膜厚が150μmとなるように調節して塗装した。そして、一週間室内で養生後、試験材とした。
(a) Preparation of corrosion resistance test material using epoxy resin paint Steel material is cut into length: 100mm, width: 75mm, thickness: 6mm, both sides are finished with grit blast (surface finish ISO Sa 2.5), and ultrasonic in acetone Degreasing was performed for 5 minutes, and then air-dried to obtain a coating corrosion resistance test material. One side was used as a surface to be coated, and the other side and the end surface were sealed with a solvent-type epoxy resin paint and further covered with a silicon-based sealant. Moreover, an epoxy resin paint (Epomarine manufactured by Kansai Paint Co., Ltd.) was applied as a paint on the blast surface by airless spray. The coating film thickness was adjusted so that the film thickness after drying was 150 μm. And it was set as the test material after curing indoors for one week.
(ｂ) 長期間にわたる塗装耐食性の調査
試験材の中央部に、幅：１mm、長さ：50mmの初期欠陥を、厚刃のカッターで設けた。この試験材を、図１で記号Ｉ，II，IIIおよびIVに示す領域での試験を行った。
(1) 領域Ｉに該当する試験
JFEスチール東日本製鉄所岸壁脇の環境(Wet率：35％、飛来塩分量：0.7mdd相当)で、暴露試験を１年間実施した。試験片を回収後、クロスカット部からの膨れ幅の最大値の測定結果から、以下のように判定した。
◎：膨れ幅５mm以下
○：膨れ幅５mm超、10mm以下
△：膨れ幅10mm超、15mm以下
×：膨れ幅15mm超
(2) 領域IIに該当する試験
塩水噴霧（SST：35℃，5％NaCl溶液)：0.5時間、湿潤（40℃，95％RH)：1.5時間、乾燥(50℃，25％RH)：４時間の、合計６時間を１サイクルとする、複合サイクル腐食試験に供した。本試験は、Wet率：33.3％、飛来塩分量：100mdd以上に相当する。この試験を、49日間行い、試験槽から取り出し水洗した後、クロスカット部からの最大膨れ（剥離）幅を計測した。その後膨れ幅の最大値測定結果から、以下のように判定した。
◎：膨れ幅５mm以下
○：膨れ幅５mm超、10mm以下
△：膨れ幅10mm超、15mm以下
×：膨れ幅15mm超
(3) 領域IIIに該当する試験
JFEスチール東日本製鉄所内の海上暴露試験場（Wet率：65％、飛来塩分量：５mdd相当)にて、半年間の暴露試験を実施した。試験片を回収後、クロスカット部からの膨れ幅の最大値の測定結果から、以下のように判定した。
◎：膨れ幅５mm以下
○：膨れ幅５mm超、10mm以下
△：膨れ幅10mm超、15mm以下
×：膨れ幅15mm超
(4) 領域IVに相当する試験
塩水噴霧（SST：35℃，5％NaCl溶液)：30分、湿潤 (40℃，95％RH)：3.5時間、乾燥(50℃，25％RH)：２時間の、合計６時間を１サイクルとする、複合サイクル腐食試験に供した。本試験は、Wet率：66.6％、飛来塩分量：100mdd以上に相当する、この試験を、35日間行い、試験槽から取り出し水洗した後、クロスカット部からの最大膨れ（剥離）幅を計測した。その後膨れ幅の最大値測定結果から、以下のように判定した。
◎：膨れ幅５mm以下
○：膨れ幅５mm超、10mm以下
△：膨れ幅10mm超、15mm以下
×：膨れ幅15mm超
得られた結果を表３に示す。
(b) Investigation of long-term coating corrosion resistance An initial defect having a width of 1 mm and a length of 50 mm was provided in the center of the test material with a thick blade cutter. This test material was tested in the region indicated by symbols I, II, III and IV in FIG.
(1) Test applicable to Area I
An exposure test was conducted for one year in an environment beside the quay of JFE Steel East Japan Works (wet rate: 35%, incoming salt content: equivalent to 0.7 mdd). After collecting the test piece, it was determined as follows from the measurement result of the maximum value of the swollen width from the crosscut portion.
◎: Swelling width 5 mm or less ○: Swelling width 5 mm or more, 10 mm or less △: Swelling width 10 mm or more, 15 mm or less ×: Swelling width 15 mm or more
(2) Tests applicable to Region II Salt spray (SST: 35 ° C, 5% NaCl solution): 0.5 hours, wet (40 ° C, 95% RH): 1.5 hours, dry (50 ° C, 25% RH): 4 The combined cycle corrosion test was performed with a total of 6 hours as one cycle. This test corresponds to a wet rate of 33.3% and an incoming salt content of 100 mdd or more. This test was conducted for 49 days, taken out from the test tank and washed with water, and then the maximum swelling (peeling) width from the crosscut portion was measured. Thereafter, from the result of measuring the maximum value of the swollen width, it was determined as follows.
◎: Swelling width 5 mm or less ○: Swelling width 5 mm or more, 10 mm or less △: Swelling width 10 mm or more, 15 mm or less ×: Swelling width 15 mm or more
(3) Tests applicable to Region III
A half-year exposure test was carried out at the JFE Steel East Japan Works' marine exposure test site (wet rate: 65%, incoming salt content: equivalent to 5 mdd). After collecting the test piece, it was determined as follows from the measurement result of the maximum value of the swollen width from the crosscut portion.
◎: Swelling width 5 mm or less ○: Swelling width 5 mm or more, 10 mm or less △: Swelling width 10 mm or more, 15 mm or less ×: Swelling width 15 mm or more
(4) Test corresponding to region IV Salt spray (SST: 35 ° C, 5% NaCl solution): 30 minutes, wet (40 ° C, 95% RH): 3.5 hours, dry (50 ° C, 25% RH): 2 The combined cycle corrosion test was performed with a total of 6 hours as one cycle. This test is equivalent to a wet rate of 66.6% and an incoming salt content of 100 mdd or more. This test was carried out for 35 days, taken out from the test tank, washed with water, and then measured for the maximum swelling (peeling) width from the crosscut part . Thereafter, from the result of measuring the maximum value of the swollen width, it was determined as follows.
：: Swelling width 5 mm or less ○: Swelling width 5 mm or more, 10 mm or less △: Swelling width 10 mm or more, 15 mm or less ×: Swelling width 15 mm or less Table 3 shows the results obtained.
表３から明らかなように、本発明に従い、使用環境に応じて（10Ｗ/Cu）比を適正に調整することにより、各使用環境において優れた塗装耐食性が得られることが分かる。
これに対し、成分組成が発明範囲から外れた比較例はいずれも、塗装耐食性が悪いことが分かり、発明例と比較例の対比から、本発明の改善効果は明らかである。
As is apparent from Table 3, it can be seen that excellent coating corrosion resistance can be obtained in each use environment by appropriately adjusting the (10 W / Cu) ratio according to the use environment according to the present invention.
On the other hand, it can be seen that any of the comparative examples in which the component composition is out of the scope of the invention has poor coating corrosion resistance, and the improvement effect of the present invention is clear from the comparison between the inventive examples and the comparative examples.
Claims (3)
Ｃ：0.03〜0.3％、
Si：0.01〜1.0％、
Mn：0.1〜2.0％、
Ｐ：0.03％以下、
Ｓ：0.005％以下、
Ｗ：0.01％以上、0.10％未満および
Cu：0.01〜0.5％
を、ＷとCuの合計が0.3≦10Ｗ＋Cu≦1.0を満足する範囲で含有し、残部はFeおよび不可避的不純物からなり、図１に示す４つの環境区分（領域Ｉ、領域II、領域III、領域IV）に応じて、ＷとCuの質量比を、下記式で示す範囲に調整することを特徴とする塗装耐食性に優れた鋼材。
記
領域Ｉの時 0.1≦10Ｗ/Cu≦１
領域IIの時 ３≦10Ｗ/Cu≦30
領域IIIの時 １≦10Ｗ/Cu≦３
領域IVの時 ３≦10Ｗ/Cu≦30 % By mass
C: 0.03-0.3%,
Si: 0.01 to 1.0%
Mn: 0.1-2.0%
P: 0.03% or less,
S: 0.005% or less,
W: 0.01% or more, less than 0.10% and
Cu: 0.01-0.5%
In the range where the total of W and Cu satisfies 0.3 ≦ 10W + Cu ≦ 1.0, and the balance is made of Fe and inevitable impurities, and the four environmental categories (region I, region II, region III, region shown in FIG. According to IV), a steel material excellent in coating corrosion resistance, characterized in that the mass ratio of W and Cu is adjusted to a range represented by the following formula.
Record
In Region I 0.1 ≦ 10W / Cu ≦ 1
In Region II 3 ≦ 10W / Cu ≦ 30
In Region III 1 ≦ 10W / Cu ≦ 3
In Region IV 3 ≦ 10W / Cu ≦ 30
Ge：0.005〜0.1％、
Sb：0.005〜0.1％、
Bi：0.005〜0.1％および
Se：0.005〜0.1％
のうちから選んだ１種または２種以上を含有することを特徴とする請求項１に記載の鋼材。 The steel material is further mass%,
Ge: 0.005-0.1%
Sb: 0.005 to 0.1%,
Bi: 0.005-0.1% and
Se: 0.005-0.1%
The steel material according to claim 1, comprising one or more selected from among the above.
Nb：0.005〜0.1％、
Ｖ：0.005〜0.1％および
Ti：0.005〜0.1％
のうちから選んだ１種または２種以上を含有することを特徴とする請求項１または２に記載の鋼材。 The steel material is further mass%,
Nb: 0.005 to 0.1%,
V: 0.005-0.1% and
Ti: 0.005-0.1%
The steel material according to claim 1 or 2, comprising one or more selected from among the above.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03183740A (en) * | 1989-12-12 | 1991-08-09 | Nippon Steel Corp | Salt-resistant reinforcing bar for preventing deterioration of concrete |
| JP2009046750A (en) * | 2007-08-22 | 2009-03-05 | Jfe Steel Kk | Corrosion-resistant steel material for ship and manufacturing method therefor |
| JP2010222665A (en) * | 2009-03-25 | 2010-10-07 | Jfe Steel Corp | Corrosion resistant shape steel member for crude oil tank and method for producing the same |
| JP2010229526A (en) * | 2009-03-30 | 2010-10-14 | Jfe Steel Corp | Highly-corrosion-resistant painted steel material |
| JP2011021247A (en) * | 2009-07-16 | 2011-02-03 | Jfe Steel Corp | Steel for ship having excellent coating film blistering resistance |
-
2012
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03183740A (en) * | 1989-12-12 | 1991-08-09 | Nippon Steel Corp | Salt-resistant reinforcing bar for preventing deterioration of concrete |
| JP2009046750A (en) * | 2007-08-22 | 2009-03-05 | Jfe Steel Kk | Corrosion-resistant steel material for ship and manufacturing method therefor |
| JP2010222665A (en) * | 2009-03-25 | 2010-10-07 | Jfe Steel Corp | Corrosion resistant shape steel member for crude oil tank and method for producing the same |
| JP2010229526A (en) * | 2009-03-30 | 2010-10-14 | Jfe Steel Corp | Highly-corrosion-resistant painted steel material |
| JP2011021247A (en) * | 2009-07-16 | 2011-02-03 | Jfe Steel Corp | Steel for ship having excellent coating film blistering resistance |
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