JP2718337B2 - Rust stabilization evaluation method for weathering steel - Google Patents
Rust stabilization evaluation method for weathering steelInfo
- Publication number
- JP2718337B2 JP2718337B2 JP5031634A JP3163493A JP2718337B2 JP 2718337 B2 JP2718337 B2 JP 2718337B2 JP 5031634 A JP5031634 A JP 5031634A JP 3163493 A JP3163493 A JP 3163493A JP 2718337 B2 JP2718337 B2 JP 2718337B2
- Authority
- JP
- Japan
- Prior art keywords
- rust
- feooh
- rust layer
- steel
- stabilization
- 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 - Lifetime
Links
Landscapes
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、耐候性鋼材の錆の安定
化の評価方法に係り、大気腐食環境に対する保護作用を
示す安定錆層の安定化度合いを適確かつ容易に評価する
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating rust stabilization of weathering steel, and more particularly to a method for accurately and easily evaluating the degree of stabilization of a stable rust layer exhibiting a protective action against an atmospheric corrosion environment. .
【0002】[0002]
【従来の技術】一般に、鋼にP、Cu、Cr、Ni等の
元素を添加することにより、大気中における耐食性を向
上させることができる。これらの低合金鋼は、耐候性鋼
と呼ばれており、屋外において数年から数十年で腐食に
対して保護性のある錆(以下、安定錆という)を形成
し、以後塗装等の防食処理作業を不要とするいわゆるメ
ンテナンスフリー鋼である。2. Description of the Related Art Generally, corrosion resistance in the atmosphere can be improved by adding elements such as P, Cu, Cr, and Ni to steel. These low-alloy steels are called weather-resistant steels and form rust (hereinafter referred to as stable rust) that protects against corrosion in the outdoors for several years to several decades. This is a so-called maintenance-free steel that does not require processing.
【0003】しかし、耐候性鋼に安定錆が形成されるま
でには長期間を要するとともに、環境条件によりその安
定化までに必要な期間が大きく異なる。さらに、環境条
件によっては安定錆が形成されない場合もある。すなわ
ち、耐候性鋼を構造物等に使用した場合、個々の使用環
境により安定錆の形成までに要する時間が異なるが、そ
の時間を把握することは、適切な時期における防食処理
の必要性などの観点から重要であるものの、著しい困難
性を伴う。However, it takes a long time for stable rust to be formed on weathering steel, and the time required for stabilization varies greatly depending on environmental conditions. Further, stable rust may not be formed depending on environmental conditions. In other words, when weather-resistant steel is used for structures, etc., the time required for the formation of stable rust varies depending on the individual use environment, but it is important to know the time required for anticorrosion treatment at an appropriate time. Important from a point of view, but with significant difficulty.
【0004】ところで、大気腐食によって生じた錆層が
安定化して安定錆となるまでの期間中には、赤錆や黄錆
等の浮き錆や流れ錆を生じてしまい、外見的に好ましく
ないばかりでなく、周囲環境の汚染の原因にもなるの
で、その対策を構じるためにも錆層の安定化度を適確に
把握する必要がある。[0004] By the way, during the period until the rust layer formed by atmospheric corrosion is stabilized and becomes stable rust, floating rust such as red rust and yellow rust and flowing rust are generated, which is not only externally undesirable. It also causes pollution of the surrounding environment. Therefore, it is necessary to accurately understand the degree of stabilization of the rust layer in order to take measures against the contamination.
【0005】一方、従来の錆層の安定化度の評価方法と
して、素地鋼材の重量減少から腐食量の経時的変化を測
定して評価することが指摘さている(日本鋼管技報、N
o.46,250(1969) )。On the other hand, it has been pointed out that as a conventional method of evaluating the degree of stabilization of a rust layer, a change with time in the amount of corrosion is measured and evaluated from the weight reduction of a base steel material (Nippon Kokan Technical Report, N
o. 46,250 (1969)).
【0006】[0006]
【発明が解決しようとする課題】しかし、この方法は、
実験室においては有効であるとしても、一旦構築された
構造物の場合においては、その重量減少を実測すること
は実質的に不可能である。However, this method is
Although effective in the laboratory, it is virtually impossible to measure the weight loss of a structure once constructed.
【0007】したがって、本発明の課題は、耐候性鋼材
の錆層の安定化度を適確に評価できるようにし、しかも
構築された構造物の耐候性鋼材の錆層についても評価で
きるようにすることにある。Accordingly, an object of the present invention is to make it possible to accurately evaluate the degree of stabilization of a rust layer of a weather-resistant steel material, and to evaluate the rust layer of a weather-resistant steel material of a constructed structure. It is in.
【0008】[0008]
【課題を解決するための手段】上記課題を解決するた
め、本発明は、耐候性鋼材の錆層を極少量採取し、その
採取粉末全量に対するα−FeOOH量の割合、および
前記採取粉末中に存在するα−FeOOHの平均結晶粒
径のうち少なくとも一方を測定することにより、前記錆
層の安定化度を評価することを、その構成とするもので
ある。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for collecting a very small amount of a rust layer of a weather-resistant steel material, the ratio of the amount of α-FeOOH to the total amount of the collected powder, and The constitution is to evaluate the degree of stabilization of the rust layer by measuring at least one of the average crystal grain diameters of α-FeOOH present.
【0009】なお、本発明にいう錆層の安定化度とは、
安定錆の生成の有無またはその過程、ならびに安定錆の
生成度合いまたは防食性のレベルの両者を含む意味であ
る。[0009] The degree of stabilization of the rust layer referred to in the present invention is:
The meaning includes both the presence or absence or the process of formation of stable rust, and the degree of formation of stable rust or the level of corrosion resistance.
【0010】また、本発明にいう耐候性鋼材とは、表面
に安定錆を形成し得る鋼材すべてを指しており、JIS G
3114(耐候性鋼:SMA)およびJIS G 3125(高耐候性
鋼:SPA)に規定される溶接構造用耐候性熱間圧延鋼
材および高耐候性圧延鋼材などの他に、表面処理等によ
り安定錆を形成し得る鋼材等も含む。The term “weather-resistant steel material” as used in the present invention refers to all steel materials capable of forming stable rust on the surface.
3114 (Weather-resistant steel: SMA) and JIS G 3125 (High weather-resistant steel: SPA) Stable rust due to surface treatment, etc., in addition to weather-resistant hot-rolled steel and highly weather-resistant rolled steel for welded structures And the like, which can form steel.
【0011】[0011]
(錆層採取粉末全量に対するα−FeOOH量の割合に
よる評価方法について)本発明者等の長年の研究によれ
ば、α−FeOOHは耐候性鋼材を長期間暴露して形成
される高い防食性を示す安定錆の主要構成化合物であ
り、通常の大気腐食環境中では化学的に安定であり相変
態や溶解が生じないことを知見している。また、数多く
の暴露試験を通じて、錆層採取粉末全量に対するα−F
eOOH量の割合と錆層の安定化度とは密接な相関関係
が存在することが判明した。(Regarding the evaluation method based on the ratio of the amount of α-FeOOH to the total amount of the rust layer-collected powder) According to a long-term study of the present inventors, α-FeOOH has a high anticorrosion property formed by exposing a weather-resistant steel material for a long period of time. It is a major constituent of stable rust, and is known to be chemically stable in normal atmospheric corrosion environments without phase transformation or dissolution. In addition, through many exposure tests, α-F
It has been found that there is a close correlation between the ratio of the eOOH amount and the degree of stabilization of the rust layer.
【0012】したがって、適宜の時点で、錆層採取粉末
全量に対するα−FeOOH量の割合を測定することに
より、錆層の安定化度を評価でき、この方法の有効性に
顕著なものがある。Therefore, at an appropriate time, the degree of stabilization of the rust layer can be evaluated by measuring the ratio of the amount of α-FeOOH to the total amount of the rust layer collected powder, and the effectiveness of this method is remarkable.
【0013】(錆層採取粉末中のα−FeOOHの平均
結晶粒径による評価方法について)さらに本発明者等の
鋭意研究の結果、錆層採取粉末中のα−FeOOHの平
均結晶粒径が小さいほど、錆層の緻密化が進んでおり安
定化度がより高いものとなっていることを突き止めた。
すなわち、上述のように錆層採取粉末全量に対するα−
FeOOH量の割合がある一定量以上で錆層は安定化す
るのであるが、その場合でもα−FeOOHの平均結晶
粒径が小さいほど、安定錆層の緻密化が進み安定化度が
さらに向上するのである。(Evaluation Method Based on Average Crystal Particle Size of α-FeOOH in Powder Collected from Rust Layer) Further, as a result of diligent research conducted by the present inventors, the average crystal grain size of α-FeOOH in the powder collected from the rust layer was small. As the density of the rust layer increased, the higher the degree of stabilization, the higher the degree of stabilization.
That is, as described above, α-
The rust layer is stabilized when the ratio of the amount of FeOOH is equal to or more than a certain amount. Even in such a case, the smaller the average crystal grain size of α-FeOOH is, the more the stable rust layer is densified and the degree of stabilization is further improved. It is.
【0014】したがって、前記方法により安定錆形成を
確認した後において、錆層採取粉末中のα−FeOOH
の平均結晶粒径を測定することにより、安定錆の防食性
を適確に評価できる。Therefore, after confirming the formation of stable rust by the above method, α-FeOOH
By measuring the average crystal grain size, the corrosion resistance of stable rust can be accurately evaluated.
【0015】以上の方法は、耐候性鋼材の錆層を極少量
採取し、その採取粉末全量に対するα−FeOOH量の
割合についてはX線粉末回折法等により、また前記採取
粉末中に存在するα−FeOOHの平均結晶粒径につい
ては透過型電子顕微鏡法等により、容易に実施すること
ができる。さらに現地では極少量の錆層を採取するのみ
であり、作業性が良好である。よって、構築された構造
物の耐候性鋼材の錆層の評価についても容易である。な
お、錆層の採取に当たっては、錆層の平均的情報を得る
ために一部鋼面が露出するまで採取する方が望ましい。In the above method, a very small amount of a rust layer of a weather-resistant steel material is sampled, and the ratio of the amount of α-FeOOH to the total amount of the sampled powder is determined by X-ray powder diffraction or the like. -The average crystal grain size of FeOOH can be easily implemented by transmission electron microscopy or the like. Furthermore, only a small amount of rust layer is collected on site, and the workability is good. Therefore, it is easy to evaluate the rust layer of the weather-resistant steel material of the constructed structure. In addition, in collecting the rust layer, it is preferable to collect the rust layer until a part of the steel surface is exposed in order to obtain average information of the rust layer.
【0016】[0016]
【実施例】以下、本発明の効果を実施例により明らかに
する。本実施例に用いた試験鋼(耐候性鋼 (鋼種記号S
MA) JIS G 3114、高耐候性鋼 (鋼種記号SPA) JIS
G 3125)の化学成分を表1に示す。なお、試験片の寸法
は150 mm×60mm×3mmとし、その表面にはエメリー紙研
磨およびバフ研磨を施した。The effects of the present invention will be described below with reference to examples. The test steel (weather resistant steel (steel type symbol S
MA) JIS G 3114, high weather resistance steel (Steel type symbol SPA) JIS
G 3125) is shown in Table 1. The dimensions of the test piece were 150 mm × 60 mm × 3 mm, and the surface thereof was polished with emery paper and buffed.
【0017】[0017]
【表1】 [Table 1]
【0018】上記表1に示す各試験片を同一条件の下
に、海岸より4kmの位置のある兵庫県尼崎市の工業地帯
に20年間暴露し、一定期間毎に腐食速度(単位時間あ
たりの板厚減少量)を鋼板の重量を測定することにより
評価した。また、同一試験片の錆層をカッターナイフで
鋼面が確認できるまで約100mg採取し粉砕して粉末試
料とし、これを用いてX線粉末回折法により粉末試料全
量に対するα−FeOOH量の割合を測定するととも
に、透過型電子顕微鏡法により粉末試料中のα−FeO
OHの平均結晶粒径を測定した(この際、α−FeOO
Hの同定は電子線回折パターンにより行った)。Under the same conditions, each of the test pieces shown in Table 1 was exposed to an industrial area in Amagasaki City, Hyogo Prefecture, 4 km from the coast, for 20 years, and the corrosion rate (plate per unit time) was determined at regular intervals. The thickness reduction) was evaluated by measuring the weight of the steel sheet. Further, about 100 mg of the rust layer of the same test piece was sampled with a cutter knife until the steel surface was confirmed and ground to obtain a powder sample. Using this, the ratio of the amount of α-FeOOH to the total amount of the powder sample was determined by X-ray powder diffraction. Measurement and α-FeO in the powder sample by transmission electron microscopy.
The average crystal grain size of OH was measured (at this time, α-FeOO
H was identified by an electron diffraction pattern).
【0019】図1に粉末試料全量に対するα−FeOO
H量の割合と鋼板の腐食速度の関係を示す。図1を参照
すると、α−FeOOH量が粉末試料全量のほぼ50%
以上になると、腐食速度は大幅に低下しており、錆層が
安定化したことが判る。FIG. 1 shows α-FeOO with respect to the total amount of the powder sample.
The relationship between the ratio of the amount of H and the corrosion rate of the steel sheet is shown. Referring to FIG. 1, the amount of α-FeOOH is approximately 50% of the total amount of the powder sample.
Above the above, the corrosion rate was significantly reduced, indicating that the rust layer was stabilized.
【0020】また、図2に粉末試料中のα−FeOOH
の平均結晶粒径と鋼板の腐食速度の関係を示す。なお、
○はα−FeOOHの重量割合が50±5%のものにお
いての結果であり、●はα−FeOOHの重量割合が7
5±5%のものにおいての結果である。α−FeOOH
量の割合が50%以上の場合には、上述のように錆層が
安定錆となったが、その場合でもα−FeOOHの平均
結晶粒径が100nm以下であると、腐食速度はさらに
低下しており、安定錆がより緻密で安定化度の高いもの
となっていることが確認できる。FIG. 2 shows α-FeOOH in the powder sample.
Shows the relationship between the average grain size and the corrosion rate of the steel sheet. In addition,
○ indicates the results when the weight ratio of α-FeOOH is 50 ± 5%, and ● indicates that the weight ratio of α-FeOOH is 7%.
The results are for 5 ± 5%. α-FeOOH
When the amount ratio is 50% or more, the rust layer becomes stable rust as described above. However, even in this case, when the average crystal grain size of α-FeOOH is 100 nm or less, the corrosion rate further decreases. This confirms that the stable rust is denser and has a higher degree of stabilization.
【0021】[0021]
【発明の効果】以上の通り、本発明によれば、耐候性鋼
材の錆層の安定化度を適確に評価でき、しかも構築され
た構造物の耐候性鋼材の錆層についても容易に評価でき
る。As described above, according to the present invention, the degree of stabilization of the rust layer of the weathering steel can be accurately evaluated, and the rust layer of the weathering steel of the constructed structure can be easily evaluated. it can.
【図1】粉末試料全量に対するα−FeOOH量の割合
と鋼板の腐食速度の関係を示す図である。FIG. 1 is a graph showing the relationship between the ratio of the amount of α-FeOOH to the total amount of a powder sample and the corrosion rate of a steel sheet.
【図2】粉末試料中のα−FeOOHの平均結晶粒径と
鋼板の腐食速度の関係を示す図である。FIG. 2 is a graph showing the relationship between the average crystal grain size of α-FeOOH in a powder sample and the corrosion rate of a steel sheet.
Claims (1)
取粉末全量に対するα−FeOOH量の割合、および前
記採取粉末中に存在するα−FeOOHの平均結晶粒径
のうち少なくとも一方を測定することにより、前記錆層
の安定化度を評価することを特徴とする耐候性鋼材の錆
安定化評価方法。A rust layer of a weather-resistant steel material is sampled in a very small amount, and at least one of a ratio of an amount of α-FeOOH to the total amount of the sampled powder and an average crystal grain size of α-FeOOH present in the sampled powder is determined. A rust stabilization evaluation method for weathering steel, wherein the degree of stabilization of the rust layer is evaluated by measuring.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5031634A JP2718337B2 (en) | 1993-02-22 | 1993-02-22 | Rust stabilization evaluation method for weathering steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5031634A JP2718337B2 (en) | 1993-02-22 | 1993-02-22 | Rust stabilization evaluation method for weathering steel |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH06241982A JPH06241982A (en) | 1994-09-02 |
JP2718337B2 true JP2718337B2 (en) | 1998-02-25 |
Family
ID=12336647
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5031634A Expired - Lifetime JP2718337B2 (en) | 1993-02-22 | 1993-02-22 | Rust stabilization evaluation method for weathering steel |
Country Status (1)
Country | Link |
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JP (1) | JP2718337B2 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100319302B1 (en) | 1999-02-25 | 2002-01-04 | 구마모토 마사히로 | Steel excellent in anticorrosion and steel structures thereof |
JP5201806B2 (en) * | 2006-05-12 | 2013-06-05 | 日本発條株式会社 | Coated steel with excellent corrosion resistance and corrosion fatigue resistance |
CN110093599B (en) * | 2019-05-15 | 2021-04-20 | 北京创氪材料科技有限公司 | Stabilizer for promoting formation of weathering steel rust layer and preparation method of weathering steel rust layer |
-
1993
- 1993-02-22 JP JP5031634A patent/JP2718337B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
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JPH06241982A (en) | 1994-09-02 |
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