No abstract

No abstract

This paper presents various models (dose-response functions, DRFs) for predicting the first-year corrosion losses of structural metals for areas with marine and marine-urban (industrial) atmospheres. The prediction results for the first-year corrosion losses (C 1 pr ) calculated by the DRF from the ISO 9223 standard and by the DRF developed by us are presented. A comparative assessment of the results is given. In this work, we used experimental data on the corrosion losses of carbon steel (CS), Zn, Cu, and Al over the first year of exposure (C 1 ex ) at coastal test locations conducted within the MICAT project and the Russian programmes. The atmosphere corrosivity parameters necessary for the DRFs were considered for these locations. It was shown that the development of DRFs that provide the most reliable C 1 pr requires experimental data from one-year metal exposures with orientation of the samples in the direction facing the predominant sea wind directions.

Based on the results of 1-year tests at 12 sites in the Far Eastern region of Russia, priority doseresponse functions (DRFs) that provide the best match with experimental data on corrosion losses for carbon steel and zinc have been selected. Long-term (up to 50 years) predictions of corrosion losses of these metals in the continental territory of Russia have been given. A comparative estimation of the mass loss predictions by priority DRFs and the power-linear model has also been given.

The knowledge of the first-year corrosion losses of metals (K1) in various regions of the world is of great importance in engineering applications. The K1 values are used to determine the categories of atmospheric corrosivity, and K1 is also the main parameter in models for the prediction of long-term corrosion losses of metals. In the absence of experimental values of K1, their values can be predicted on the basis of meteorological and aerochemical parameters of the atmosphere using the dose-response functions (DRF). Currently, the DRFs presented in ISO 9223:2012(E) /1/ standard are used for predicting K1 in any region of the world, along with the unified DRFs /2/ and the new DRFs /3/. The predicted values of corrosion losses (K1pr) of carbon steel, zinc, copper and aluminum obtained by various DRFs for various continental regions of the world are presented. In this work we used the atmosphere corrosivity parameters and experimental data on the corrosion losses of metals for the first year of exposure (K1exp) for the locations of the tests performed under the international UN/ECE program, the MICAT project, and the Russian program. For the first time, a comparative assessment of the reliability of various DRFs is given by comparing the values of K1pr and K1ex using graphical and statistical methods. The statistical indicators of reliability of predicting the corrosion losses of metals are calculated for various categories of atmosphere corrosivity. It is shown that the new dose-response functions offer the highest reliability for all categories of atmosphere corrosivity.