The Development of Corrosion Processes on Weathering Steel Bridges

AbstractThis paper deals with experimental corrosion tests carried out on weathering steel bridges. The basic property of the weathering steel is its ability to create a protective layer on its surface in favorable environments. This protective layer called patina covers the surface of the whole structure, protects against external climatic influences and the construction resists completely without an anticorrosion coating. This paper presents the program of experimental atmospheric corrosion test carried out on road bridges made of weathering structural steel. The article presents results of corrosion tests after one year of exposure of corrosion specimens. This paper describes the influence of the position and location of an exposed surface, evaluates the different development on typical surfaces affected by leaking water and explains the high degree of correlation dependence between measured corrosion loss and average thickness of corrosion products

On the corrosion and soiling effects on materials by air pollution in Athens, Greece

In the frame of the European project, entitled MULTI-ASSESS, specimens of structural metals, glass, stone and concrete materials were exposed to air pollution at a station, which was installed for this purpose on a building, located in the centre of Athens. The main purpose of this project was to determine the corrosion and soiling effects of air pollution on materials. A set of the specimens was exposed in a position that was sheltered from rain and partly from wind, and another set was exposed in unsheltered positions on the roof of the above said building. In addition, other specimens were exposed at different heights on the same building, in order to investigate for the first time the corrosion and soiling effects on various materials as a function of height. For the determination of these effects, chemical analysis of the specimens was performed and basic parameters as the weight change, the layer thickness and the optical properties were calculated. Finally, the results obtained are discussed and their plausible interpretation is attempted

The Results of 45 Years of Atmospheric Corrosion Study in the Czech Republic

Atmospheric corrosion poses a significant problem with regard to destruction of various materials, especially metals. Observations made over the past decades suggest that the world’s climate is changing. Besides global warming, there are also changes in other parameters. For example, average annual precipitation increased by nearly 10% over the course of the 20th century. In Europe, the most significant change, from the atmospheric corrosion point of view, was an increase in SO2 pollution in the 1970s through the 1980s and a subsequent decrease in this same industrial air pollution and an increase in other types of air pollution, which created a so-called multi-pollutant atmospheric environment. Exposed metals react to such changes immediately, even if corrosion attack started in high corrosive atmospheres. This paper presents a complex evaluation of the effect of air pollution and other environmental parameters and verification of dose/response equations for conditions in the Czech Republic

Restaurovani bronzovych a medenych monumentu - prilohy casopisu Zpravy pamatkove pece.

Supplement: 1 CD-ROM (Restoring of bronze and copper monuments).Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Characterization of Corrosion Products on Weathering Steel Bridges Influenced by Chloride Deposition

The article presents the results of experimental testing of corrosion processes on weathering steel bridges. Two bridge structures spanning various obstacles were selected for the experimental measurement. The tested bridges are situated in the same location and structural solution of these bridges is similar. Differences in development of corrosion products are mainly affected by the microclimate below the bridge structure. Special attention is paid to a bridge over the motorway which is strongly affected by the deposition of chlorides. The dependences between the measured deposition of chlorides and parameters of corrosion layers (thickness of corrosion products, corrosion rates, and chemical composition) are discussed and evaluated in this article

Cracking of ferritic stainless steel tubes during production process

From the economic reasons many products originally made from austenite stainless steel are nowadays made from ferritic stainless steel. Ferritic steels have relatively low yield strength and the work hardening is limited. They cannot be hardened by heat treatment and only moderately hardened by cold working. Commercially made stainless steel tubes from ferritic steel, used for industrial plumbing was examined on presence of cracks. The cracking was present on the inner side of the convoluted tube shape. The tube manufacturing process consisted of continual bending of the sheet to tube shape, weld the tube, then of cold shaping by pulling through rib-forming frames, which is done in several steps. Then thermal treatment applies to the nearly finished product to remove stress remaining in the structure. Prime suspect was deformation beyond the ductility of used material. However the stress-strain tensile testing does not approved this hypothesis. Several samples of failed material were taken together with reference, and were examined by optical microscopy, and X-Ray Diffraction structure analysis. The structure of the cracked tubes does not show the signs of deformation over the limit, except the location near to the crack itself. Interestingly enough the failed material showed more homogenous structure than the original one. Needle like structures were found when the material is "overetched", on these structures concentration of stress under bending occur. This structure was identified as - ferrite however its presence in -ferrite matrix is unclear