The Influence of Test-Panel Orientation and Exposure Angle on the Corrosion Rate of Carbon Steel. Mathematical Modelling

Abstract

The effects of both test-panel orientation and exposure angle on the atmospheric corrosion rates of carbon steel probes exposed to a marine atmosphere were investigated. Test samples were exposed in a tree-shape metallic frame with either three exposure angles of 30°, 45° and 60° and orientation north-northeast (N-NE), or eight different orientation angles around a circumference. It was found that the experimental corrosion rates of carbon steel decreased for the specimens exposed with greater exposure angles, whereas the highest corrosion rates were found for those oriented to N-NE due to the influence of the prevailing winds. The obtained data obtained were fitted using the bi-logarithmic law and its variations as to take in account the amounts of pollutants and the time of wetness (TOW) for each particular case with somewhat good agreement, although these models failed when all the effects were considered simultaneously. In this work, we propose a new mathematical model including qualitative variables to account for the effects of both exposure and orientation angles while producing the highest quality fits. The goodness of the fit was used to determine the performance of the mathematical models.

A Digital Twin concept for the prescriptive maintenance of protective coating systems on wind turbine structures

“…(A virtual compass rose generated with the proposed Virtual Twin computation procedure is already added to the figure.) Effects of geographical orientation and inclination angle on the corrosion of steel panels were also reported by Santana et al (2020). Table 1, where corrosion values for aluminum in diverse micro-environments are listed for different geographical orientations, illustrates more complex relationships (Klassen et al, 2002).…”

“…Effects of local and micro-environmental effects on the corrosion of steel structures were investigated by several authors, whereby the intensity of corrosion was found to depend on geographical location, geographical orientation, inclination angle, and local structural design (e.g. sheltering) (Jeffrey and Melchers, 2008; Klassen et al, 2002; Kühne, 2015; Santana et al, 2020; Slamova et al, 2012); thus on particular reference areas. The importance of the geographical location for the intensity of environmental (corrosive) loads is highlighted in Figure 6, where salinity (world-wide) and wind direction (Europe) above marine locations are mapped (Slamova et al, 2012).…”

Corrosion resistance of structural metals depending on the sample orientation and initial exposure conditions in coastal and rural atmospheres. Part 1. Corrosivity toward structural metals at coastal and rural test sites under various exposure conditions

“…At present, no mathematical models for C 1 prediction depending on the exposure conditions of metal samples are available. Only Santana et al [35] suggested mathematical models for the prediction of the variation in the corrosion rate ( CR ) of carbon steel for a time of up to 7 years depending on the atmosphere parameters, the angle of inclination of samples (30°, 45° and 90° relative to the horizon) and their orientation relative to the wind orientation (N, NE, E, SE, S, SW, W and NW). Experimental data were obtained in 6 exposures of samples that lasted from 60 to 396 days.…”

Corrosion and Protection of Metals

“…Both works by Santana et al reported on atmospheric corrosion of zinc, copper and carbon steel [12,13]. It was found that the most influential environmental parameter affecting the corrosion rates was the chloride deposition rate (S d ), and on the contrary, the environmental temperature (T) showed the smallest influence.…”