Aqueous corrosion characteristics of carbon steel and weathering steel in aerated acid-chloride solutions were studied by using immersion weight loss tests, crevice corrosion tests, electrochemical measurements, and analytical techniques. Neither carbon steel nor weathering steel showed passive behavior in these acid-chloride solutions. Corrosion morphology was examined using scanning electron microscopy (SEM). Surface morphology showed uniform attack with some shallow pits. Weathering steel was not susceptible to crevice corrosion because of the small potential difference between the steel within the crevice and the steel outside the crevice. Weathering steel was more resistant to acid-chloride solutions than plain carbon steel. The better corrosion resistance of the weathering steel is attributed to protectiveness of the surface layer. X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) analyses revealed that the rust layer formed in acid-chloride solution was composed of hematite (Fe2O3) and magnetite (Fe3O4). From XPS analyses, however, there were some Cr and Cu compounds in the rust layer of the weathering steel. These compounds act as a factor for corrosion resistance in aqueous solutions.
Weathering steel is commonly used as a cost-effective alternative for bridge superstructures, as the costs and environmental impacts associated with the maintenance/replacement of paint coatings are theoretically eliminated. The performance of weathering steel depends on the proper formation of a surface patina, which consists of a dense layer of corrosion product used to protect the steel from further atmospheric corrosion. The development of the weathering steel patina may be hindered by environmental factors such as humid environments, wetting/drying cycles, sheltering, exposure to de-icing chlorides, and design details that permit water to pond on steel surfaces. Weathering steel bridges constructed over or adjacent to other roadways could be subjected to sufficient salt spray that would impede the development of an adequate patina. Addressing areas of corrosion on a weathering steel bridge superstructure where a protective patina has not formed is often costly and negates the anticipated cost savings for this type of steel superstructure. Early detection of weathering steel corrosion is important to extending the service life of the bridge structure; however, written inspection procedures are not available for inspectors to evaluate the performance or quality of the patina. This project focused on the evaluation of weathering steel bridge structures, including possible methods to assess the quality of the weathering steel patina and to properly maintain the quality of the patina. The objectives of this project are summarized as follows: Identify weathering steel bridge structures that would be most vulnerable to chloride contamination, based on location, exposure, environment, and other factors.
Identify locations on an individual weathering steel bridge structure that would be most susceptible to chloride contamination, such as below joints, splash/spray zones, and areas of ponding water or debris.
Identify possible testing methods and/or inspection techniques for inspectors to evaluate the quality of the weathering steel patina at locations discussed above.
Identify possible methods to measure and evaluate the level of chloride contamination at the locations discussed above.
Evaluate the effectiveness of water washing on removing chlorides from the weathering steel patina.
Develop a general prioritization for the washing of bridge structures based on the structure’s location, environment, inspection observations, patina evaluation findings, and chloride test results.
Original Corten Steel Weather Resistant Sheet Steel
Carbon Steel, Corten Steel, Stainless steel
Rust, Bare, Powder Coated, Polished, Black Heat-resisting Paint, Iron Oxide
Diameter : 320mm--1200mm
Thickness : 1.2mm--3.0mm
Inside : Anti-wear foam paper
Outside : Plywood box
Free (without any condition)
OEM & ODM
Customized service is available.