JPH09125224A - High weather resisting steel - Google Patents
High weather resisting steelInfo
- Publication number
- JPH09125224A JPH09125224A JP28359495A JP28359495A JPH09125224A JP H09125224 A JPH09125224 A JP H09125224A JP 28359495 A JP28359495 A JP 28359495A JP 28359495 A JP28359495 A JP 28359495A JP H09125224 A JPH09125224 A JP H09125224A
- Authority
- JP
- Japan
- Prior art keywords
- rust
- steel
- hematite
- thickness
- high weather
- 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.)
- Granted
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- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、耐候性鋼材に関す
る。TECHNICAL FIELD The present invention relates to a weather resistant steel material.
【0002】[0002]
【従来の技術】一般に、普通鋼にP、Cu、Cr、Ni
などの元素を適量添加して低合金鋼とすることにより、
大気中における耐食性を向上させることができる。この
低合金鋼は耐候性鋼と呼ばれ、屋外において数年(通
常、5〜10年)で腐食に対して保護性のある錆を形成
し、以後塗装などの耐食表面処理を施す必要のない、い
わゆるメンテナンスフリー鋼である。2. Description of the Related Art Generally, P, Cu, Cr, Ni are added to ordinary steel.
By adding an appropriate amount of such elements as low alloy steel,
Corrosion resistance in the atmosphere can be improved. This low alloy steel is called weather resistant steel and forms rust that protects against corrosion in a few years outdoors (usually 5 to 10 years), and it is not necessary to subsequently apply corrosion resistant surface treatment such as painting. , So-called maintenance-free steel.
【0003】ところが、上記従来の耐候性鋼は、海岸地
帯などの厳しい大気腐食環境中においては保護性のある
錆を形成せず、数年経過以降も赤錆や黄錆などの浮き錆
や流れ錆が生じてしまい、外見的に好ましくないばかり
でなく、周囲環境の汚染原因にもなるという欠点を有し
ている。However, the above-mentioned conventional weathering steel does not form rust having a protective property in a severe atmospheric corrosive environment such as a coastal area, and even after several years, floating rust such as red rust and yellow rust and flow rust. Has the disadvantage that not only is it undesirable from the outside, it also causes pollution of the surrounding environment.
【0004】このため、上記浮き錆や流れ錆の発生防止
対策としては、例えば特開平1−142088号公報に
見られるように、リン酸塩皮膜を形成させる表面処理方
法がある。しかし、このような表面処理方法では、特殊
な処理溶液が多量に必要であり、かつ多大の労力を必要
とし、製品コストの上昇が避けられないよいう欠点を有
している。Therefore, as a measure for preventing the floating rust and the flow rust from occurring, there is a surface treatment method for forming a phosphate film as disclosed in, for example, Japanese Patent Laid-Open No. 1-142088. However, such a surface treatment method has a drawback in that a large amount of special treatment solution is required and a great deal of labor is required, and an increase in product cost cannot be avoided.
【0005】一方、近年、社会問題ともなっている労働
力不足や社会資本を充実させるという要求から、上記の
表面処理や塗装のような手間がかからず、かつ製品コス
トの上昇を招くことのない、メンテナンスフリーの高耐
候性鋼材の開発が強く望まれているのが実情である。On the other hand, in recent years, due to the labor shortage, which has become a social problem, and the demand for enhancing social capital, the above-mentioned surface treatment and painting are not required, and the product cost is not increased. In fact, there is a strong demand for the development of maintenance-free high weather resistance steel.
【0006】[0006]
【発明が解決しようとする課題】本発明は、上記の実情
に鑑みなされたもので、その課題は比較的簡単な処理で
鋼材の表面に優れた保護性のある錆層を形成させること
ができ、海岸地帯のような厳しい大気腐食環境下におい
ても、外見を損なう浮き錆や流れ錆が発生しないのみな
らず、製品コストの低減をも図り得る、高耐候性鋼材を
提供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to form a rust layer having an excellent protective property on the surface of a steel material by a relatively simple treatment. The present invention is to provide a high weather resistance steel material capable of reducing the product cost as well as causing no floating rust or flow rust that deteriorates the appearance even in a severe atmospheric corrosion environment such as a coastal area.
【0007】[0007]
【課題を解決するための手段】本発明においては、鋼材
の表面に所定厚さの三二酸化鉄、なかでもα型の三二酸
化鉄皮膜、すなわちヘマタイト(α−Fe2 O3 )皮膜
を形成させる。In the present invention, a ferric sesquioxide having a predetermined thickness, particularly an α-type ferric sesquioxide coating, that is, a hematite (α-Fe 2 O 3 ) coating is formed on the surface of a steel material. .
【0008】本発明者らは、海岸地帯のような厳しい大
気腐食環境下において優れた耐候性を発揮する高耐候性
鋼材を得るべく、種々の実験研究を行った結果、鋼材表
面に30nm〜200μm厚さのヘマタイト(α−Fe
2 O3 )皮膜を形成させた場合に限って、外見を損なう
浮き錆や流れ錆が全くと言って過言でないほど発生せ
ず、腐食減肉が殆どなくなることを知見した。The inventors of the present invention conducted various experimental studies in order to obtain a high weather resistance steel material exhibiting excellent weather resistance in a severe atmospheric corrosion environment such as a coastal area. As a result, the surface of the steel material was 30 nm to 200 μm. Thickness of hematite (α-Fe
It has been found that only when a 2 O 3 ) film is formed, floating rust or flow rust that impairs the appearance does not occur to the extent that it is exaggerated and corrosion thinning is almost eliminated.
【0009】本発明は、上記の知見に基づいてなされた
もので、その要旨は次の高耐候性鋼材にある。The present invention has been made on the basis of the above findings, and its gist resides in the following high weather resistance steel material.
【0010】表面が厚さ30nm〜200μmのヘマタ
イト(α−Fe2 O3 )で覆われていることを特徴とす
る高耐候性鋼材。A high weather resistance steel material having a surface covered with hematite (α-Fe 2 O 3 ) having a thickness of 30 nm to 200 μm.
【0011】[0011]
【発明の実施の形態】耐候鉄鋼材の表面に形成させるヘ
マタイト皮膜とその厚さを上記の範囲に限定した理由に
ついて、作用効果とともに説明する。BEST MODE FOR CARRYING OUT THE INVENTION The reason why the hematite film formed on the surface of a weather-resistant steel material and the thickness thereof are limited to the above range will be described together with the function and effect.
【0012】ヘマタイトは、鉄の酸化物、オキシ水酸化
物および水酸化物のなかでも、常温大気環境下におい
て、熱力学的に最も安定な酸化物であり、水と酸素が存
在しても変態することなく安定に存在する。Among iron oxides, oxyhydroxides and hydroxides, hematite is the thermodynamically most stable oxide in the atmospheric environment at room temperature, and is transformed even in the presence of water and oxygen. Existence stable without doing.
【0013】このため、このヘマタイト皮膜を形成させ
た鋼材は、その使用初期から腐食に対して極めて優れた
保護性を有しており、赤錆や黄錆などの浮き錆や流れ錆
が全くと言ってよいほど発生することがない。すなわ
ち、鋼材表面にヘマタイト皮膜を密着形成させた場合、
このヘマタイト皮膜は大気腐食環境中の水、酸素、亜硫
酸ガス、塩分などの腐食因子が金属表面に到達するのを
抑制阻止する抵抗障壁となとなるばかりでなく、これら
の腐食因子がヘマタイト自体の表面に吸着しなくなる。
この結果、赤錆や黄錆などの浮き錆や流れ錆の発生が殆
ど皆無になり、優れた耐候性を発揮することになる。Therefore, the steel material on which the hematite film is formed has an extremely excellent protection against corrosion from the beginning of its use, and it is said that floating rust such as red rust and yellow rust and flow rust are completely absent. It doesn't occur as much as you can. That is, when a hematite film is closely formed on the steel surface,
This hematite film not only acts as a resistance barrier that suppresses and prevents corrosion factors such as water, oxygen, sulfurous acid gas, and salt in the atmospheric corrosive environment from reaching the metal surface, but these corrosion factors also affect the hematite itself. No longer sticks to the surface.
As a result, almost no floating rust or flow rust such as red rust or yellow rust is generated, and excellent weather resistance is exhibited.
【0014】しかし、その厚さが30nm未満である
と、上記の腐食因子とへマタイトとの反応性が高まるた
め、ヘマタイト皮膜に部分的な微細欠陥がある場合、埃
や海塩粒子がヘマタイト皮膜の表面に付着した場合に、
鋼材表面に腐食因子が到達することにとなり、防食性が
維持されなくなる。However, if the thickness is less than 30 nm, the reactivity with the above-mentioned corrosion factors and hematite is increased, and therefore, if the hematite coating has a partial fine defect, dust or sea salt particles are not contained in the hematite coating. When it adheres to the surface of
Corrosion factors reach the surface of the steel material, and corrosion resistance cannot be maintained.
【0015】また、その厚さが200μmを超えると、
ヘマタイト皮膜中のボイドあるいは空隙(クラック)な
どの欠陥が発生し易くなったり、あるいは上記各腐食因
子との反応性が高まるため、結果として長時間大気中に
暴露するうちに腐食因子が金属表面まで到達し、赤錆や
黄錆などの浮き錆や流れ錆の発生を招く。If the thickness exceeds 200 μm,
Defects such as voids or voids (cracks) in the hematite film are more likely to occur, or the reactivity with the above corrosion factors increases, and as a result, the corrosion factors reach the metal surface during long-term exposure to the atmosphere. It reaches and causes floating rust and flow rust such as red rust and yellow rust.
【0016】よって、形成させるヘマタイト皮膜の厚さ
は、30nm〜200μmとした。Therefore, the thickness of the hematite coating formed is 30 nm to 200 μm.
【0017】本発明の高耐候性鋼材を構成する母材鋼
は、オーステナイト系やフェライト系などのステンレス
鋼やNi基合金などで、通常、沈澱型皮膜であるいわゆ
る錆を生成しない鋼種は含まず、例えばJIS−G31
25に規定される耐候性鋼、同G3106に規定される
溶接構造用鋼などの低合金鋼や炭素鋼、およびその相当
鋼、さらにはアームコ鉄などの純鉄である。すなわち、
上記の沈澱型皮膜であるいわゆる錆を生成する鋼種であ
れば、どのような鋼種であってもよい。The base steel constituting the high weather resistance steel of the present invention is austenitic or ferritic stainless steel, Ni-based alloy, etc., and does not normally include a so-called rust-free steel type which is a precipitation type film. , For example, JIS-G31
The low-alloy steels and carbon steels such as the weathering steel defined in No. 25, the welded structural steels defined in G3106, and their equivalent steels, and pure iron such as Armco iron. That is,
Any kind of steel may be used as long as it is a kind of steel that produces so-called rust which is the above-mentioned precipitation type film.
【0018】なお、上記のヘマタイト皮膜は、上記沈澱
型皮膜であるいわゆる錆を生成する鋼種からなり、形鋼
や棒鋼、板、さらには管状の各種形状に成形された鋼材
を、例えば200〜400℃の大気雰囲気炉で0.1〜
1000時間保持する熱処理を施すことにより、形成さ
せることができる。すなわち、加熱保持温度が200℃
未満であったり、保持時間が0.1時間未満あると、十
分な厚さのヘマタイト皮膜が均一に形成されないのみな
らず、ヘマタイト皮膜で覆われない部分ができ、上記の
性能を発揮できなくなる。一方、加熱保持温度が400
℃を超えたり、保持時間が1000時間を超えると、ヘ
マタイト皮膜が厚くなり過ぎ、上記の性能を満足できな
くなる。従って、その熱処理は、200〜400℃の大
気雰囲気炉で0.1〜1000時間保持する条件で行う
のが好ましい。The above-mentioned hematite film is made of a so-called rust-forming steel species which is the above-mentioned precipitation-type film, and shaped steel, steel bars, plates, and steel materials formed into various tubular shapes, for example, 200 to 400. In an atmospheric furnace at
It can be formed by performing a heat treatment for holding for 1000 hours. That is, the heating and holding temperature is 200 ° C.
If it is less than 1 hour, or if the holding time is less than 0.1 hour, not only a hematite film having a sufficient thickness is not uniformly formed, but also a part not covered with the hematite film is formed and the above performance cannot be exhibited. On the other hand, the heating and holding temperature is 400
If the temperature exceeds ℃ or the holding time exceeds 1000 hours, the hematite coating becomes too thick and the above performance cannot be satisfied. Therefore, the heat treatment is preferably carried out under the condition of holding in an air atmosphere furnace at 200 to 400 ° C. for 0.1 to 1000 hours.
【0019】このように、本発明の高耐候性鋼材は、低
温熱処理を施すのみで簡単に得ることができるので、そ
の製品コストの低減が図れる。As described above, the high weather resistance steel material of the present invention can be easily obtained only by performing the low temperature heat treatment, so that the product cost can be reduced.
【0020】[0020]
【実施例】表1に示す成分組成を有する3種類の供試材
料鋼材A〜Cから、長さ100mm、幅60mm、厚さ
3mmの試験片を採取し、その表面をエメリー研磨紙
(#1200)を用いて研磨調整した。しかる後、各試
験片を大気雰囲気の150〜450℃の温度域に所定時
間(0〜1200hr)保持することにより、種々の厚
さのヘマタイト層を形成させた。得られた各試験片を、
厳しい大気腐食環境にある北九州市の海岸地帯の海岸線
から5m離間した高さ2mの位置に、水平面に対し30
°傾斜させて設置し、300日間暴露した。Example A test piece having a length of 100 mm, a width of 60 mm and a thickness of 3 mm was taken from each of three types of test material steel materials A to C having the composition shown in Table 1, and the surface thereof was emery-polished paper (# 1200). ) Was used for polishing adjustment. Thereafter, each test piece was held in a temperature range of 150 to 450 ° C. in an air atmosphere for a predetermined time (0 to 1200 hr) to form hematite layers having various thicknesses. Each of the obtained test pieces,
At a height of 2m, 5m away from the coastline of the coastal area of Kitakyushu in a severe atmospheric corrosive environment, 30
It was installed at an angle of inclination and exposed for 300 days.
【0021】[0021]
【表1】 [Table 1]
【0022】上記の暴露試験後、目視観察して錆発生の
有無を確認し、僅かでも錆の発生しているものについて
は錆層を除去し、板厚減少量(表裏両面の平均腐食深さ
の平均値)を測定した。その測定結果を、表2に示す。After the above-mentioned exposure test, the presence or absence of rust was confirmed by visual observation, and the rust layer was removed if even a slight amount of rust was generated, and the thickness reduction amount (average corrosion depth on both front and back surfaces) Was measured. The measurement results are shown in Table 2.
【0023】[0023]
【表2】 [Table 2]
【0024】表2に示す結果から明らかなように、本発
明で規定する範囲内の厚さでヘマタイト層を形成させた
鋼材(No. 4〜15、No. 21〜32およびNo. 38〜
49)はいずれの鋼種も、浮き錆や流れ錆の錆発生は事
実上認められず、腐食減肉量も0.03μm以下と極め
て僅かで良好な耐候性を示した。As is clear from the results shown in Table 2, steel materials (No. 4 to 15, No. 21 to 32 and No. 38 to) having a hematite layer formed in a thickness within the range specified in the present invention.
No. 49) showed virtually no occurrence of rust such as floating rust and flow rust, and the corrosion thinning amount was 0.03 μm or less, which was very slight and showed good weather resistance.
【0025】これに対し、本発明で規定する範囲外の厚
さのヘマタイト層を形成させた比較例の鋼材(No. 1〜
3、No. 16〜17、No. 18〜20、No. 33〜3
4、No. 35〜37およびNo. 50〜51)はいずれの
鋼種も、錆発生が認められ、腐食減肉量も48.32μ
m以上と多く、耐候性に劣っていた。On the other hand, the steel materials of the comparative examples (No.
3, No. 16-17, No. 18-20, No. 33-3
No. 4, No. 35-37 and No. 50-51), rust generation was observed in all steel types, and the corrosion thinning amount was 48.32μ.
It was as high as m or more and was inferior in weather resistance.
【0026】[0026]
【発明の効果】本発明の高耐候性鋼材は、その表面を防
食性の高い安定なヘマタイト皮膜で覆われているので、
厳しい大気腐食環境下においても錆を発生することがな
い。この結果、本発明の鋼材を用いた建築物や構造物は
その外観が長期にわたって損なわれることがない。ま
た、その製造は簡単な熱処理を施すのみで得られ、優れ
たメンテナンスフリー性を備えるので、経済性に優れて
いる。The high weather resistance steel material of the present invention has its surface covered with a stable hematite film having high anticorrosion property.
No rust is generated even under severe atmospheric corrosion environment. As a result, the appearance of the building or structure using the steel material of the present invention will not be impaired for a long period of time. In addition, the manufacturing thereof is obtained only by performing a simple heat treatment, and since it has excellent maintenance-free property, it is excellent in economic efficiency.
Claims (1)
イト(α−Fe2 O3 )で覆われていることを特徴とす
る高耐候性鋼材。1. A high weather resistance steel material, the surface of which is covered with hematite (α-Fe 2 O 3 ) having a thickness of 30 nm to 200 μm.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7283594A JP3011077B2 (en) | 1995-10-31 | 1995-10-31 | High weather resistant steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7283594A JP3011077B2 (en) | 1995-10-31 | 1995-10-31 | High weather resistant steel |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH09125224A true JPH09125224A (en) | 1997-05-13 |
JP3011077B2 JP3011077B2 (en) | 2000-02-21 |
Family
ID=17667531
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7283594A Expired - Fee Related JP3011077B2 (en) | 1995-10-31 | 1995-10-31 | High weather resistant steel |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3011077B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6218027B1 (en) | 1999-02-25 | 2001-04-17 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd) | Steel material excellent in corrosion resistance and fabric using the same |
US7037388B2 (en) | 1998-09-30 | 2006-05-02 | Kobe Steel, Ltd. | Steel plate for paint use and manufacturing method thereof |
KR20180135263A (en) * | 2017-06-12 | 2018-12-20 | 포항공과대학교 산학협력단 | Iron substrate with hematite surface suructure and manufacturing method thereof |
US20210036335A1 (en) * | 2019-07-31 | 2021-02-04 | Robert Bosch Gmbh | Corrosion-resistant oxide films and application for fuel cell bipolar plate |
-
1995
- 1995-10-31 JP JP7283594A patent/JP3011077B2/en not_active Expired - Fee Related
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7037388B2 (en) | 1998-09-30 | 2006-05-02 | Kobe Steel, Ltd. | Steel plate for paint use and manufacturing method thereof |
US6218027B1 (en) | 1999-02-25 | 2001-04-17 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd) | Steel material excellent in corrosion resistance and fabric using the same |
KR20180135263A (en) * | 2017-06-12 | 2018-12-20 | 포항공과대학교 산학협력단 | Iron substrate with hematite surface suructure and manufacturing method thereof |
US20210036335A1 (en) * | 2019-07-31 | 2021-02-04 | Robert Bosch Gmbh | Corrosion-resistant oxide films and application for fuel cell bipolar plate |
US11205783B2 (en) * | 2019-07-31 | 2021-12-21 | Robert Bosch Gmbh | Fuel cell bipolar plate including corrosion-resistant ferric oxide layer |
Also Published As
Publication number | Publication date |
---|---|
JP3011077B2 (en) | 2000-02-21 |
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