An Overview of Major Experimental Methods and Apparatus for Measuring and Investigating Erosion-Corrosion of Ferrous-Based Steels

Hybrid system model for wind abrasion segmentation using semi-automatic classification of remote sensing multispectral areas

Wind abrasion, caused by particles transported by strong winds impacting on structures, can lead to their degradation. Although this phenomenon has hardly been studied in this context, it is becoming increasingly important due to new trends in infrastructure location, especially in renewable energy terms. Metallic structures are particularly vulnerable to degradation by the action of windblown sand particles. However, characterising such secluded sites is complicated, and remote sensing systems and satellite information become crucial. The objective of this research is to identify and delineate the geographic areas that are vulnerable to this phenomenon by employing a hybrid model with historical data and the semi-automatic classification of multispectral satellite images. The model is based on critical variables identified by the scientific community and case studies documented in the literature. The methodology used for the study consists of four phases, including creating a scientifically robust database, downloading and managing satellite and historical long-term information, segmenting the regions of interest, and modelling using supervised classification techniques. The proposed algorithm shows very accurate results (R2 = 0.9922) and the overall system approach is presented as a useful and generalizable method to address this problem, increasing the existing knowledge on material wear by particle action, and contributing to optimizing the initial design of resilient structures.

Influence of Elbow Angle on Erosion-Corrosion of 1018 Steel for Gas-Liquid-Solid Three Phase Flow

Erosive wear due to the fact of sand severely affects hydrocarbon production industries and, consequently, various sectors of the mineral processing industry. In this study, the effect of the elbow geometrical configuration on the erosive wear of carbon steel for silt–water–air flow conditions were investigated using material loss analysis, surface roughness analysis, and microscopic imaging technique. Experiments were performed under the plug flow conditions in a closed flow loop at standard atmospheric pressure. Water and air plug flow and the disperse phase was silt (silica sand) with a 2.5 wt % concentration, and a silt grain size of 70 µm was used for performing the tests. The experimental analysis showed that silt impact increases material disintegration up to 1.8 times with a change in the elbow configuration from 60° to 90° in plug flow conditions. The primary erosive wear mechanisms of the internal elbow surface were sliding, cutting, and pit propagation. The maximum silt particle impaction was located at the outer curvature in the 50° position in 60° elbows and the 80° position in 90° elbows in plug flow. The erosion rate decreased from 10.23 to 5.67 mm/year with a change in the elbow angle from 90° to 60°. Moreover, the microhardness on the Vickers scale increased from 168 to 199 in the 90° elbow and from 168 to 184 in the 60° elbow.

Corrosion Prediction of Weathered Galvanised Structures Using Machine Learning Techniques

Galvanised steel atmospheric corrosion is a complex multifactorial phenomenon that globally affects many structures, equipment, and sectors. Moreover, the International Organization of Standardization (ISO) standards require specific pollutant depositions values for any atmosphere classification or corrosion loss prediction result. The aim of this research is to develop predictive models to estimate corrosion loss based on easily worldwide available parameters. Experimental data from internationally validated studies were used for the data mining process, basing their characterisation on seven globally accessible qualitative and quantitative variables. Self-Organising Maps including both supervised and unsupervised layers were used to predict first-year corrosion loss, its corrosivity categories, and an uncertainty range. Additionally, a formula optimised with Newton’s method has been proposed for extrapolating these results to long-term results. The predictions obtained were compared with real values using Euclidean distances to know its similarity degree, offering high prediction performance. Specifically, evaluation results showed an average saving of up to 16% in coatings using these predictions. Therefore, using the proposed models reduces the uncertainty of the final structures state by predicting their material loss, avoiding initial over-dimensioning of structures, and meeting the principles of efficiency and sustainability, thus reducing costs.

The Effect of Sandblasting on Properties and Structures of the DC03/1.0347, DC04/1.0338, DC05/1.0312, and DD14/1.0389 Steels for Deep Drawing

The erosion phenomenon has a significant influence on many metallic materials used in numerous industrial sectors. In this paper, we present the results of an analysis of the influence of abrasive impact erosion on surface and properties of DC03/1.0347, DC04/1.0338, DC05/1.0312, and DD14/1.0389 deep drawing steels. The chemical composition, static tensile tests, hardness tests, drawability tests, erosion tests, microstructure analysis, surface roughness, and hardness of the plates were investigated. The wear mechanisms and wear behavior of the investigated steels were also discussed. The results obtained in this study allowed the assessment of the microstructural changes in deep drawing steels under the influence of intense erosive impact. The obtained results indicate that the erosive impact may cause a significant grain refinement of the microstructure of the surfaces of the investigated materials. Moreover, large amounts of heat released during erosive impact may cause the material phase changes. This research expands the knowledge on specific mechanisms taking place during sandblasting and their influence on the properties of deep drawing steels and their wear behavior.

Erosion–Corrosion of AISI 304L Stainless Steel Affected by Industrial Copper Tailings

A comprehensive analysis of the erosion–corrosion behavior of AISI 304L stainless steel immersed in 0.5 M NaCl solution with the addition of industrial tailing particles obtained from the copper mining industry is reported. From fundamental studies using combined measurements of potentiodynamic and weight loss techniques, the pure corrosion, pure erosion, and their synergism on the total wear rate were evaluated. The results showed that the presence of soluble chemical reagents dragged by tailing particles significantly affects the pure corrosion rate in comparison with a NaCl solution without these chemical reagents. In addition, the wear of stainless steel by pure erosion was found to be more important than that of pure corrosion. Erosion–corrosion tests performed under an open circuit potential behavior indicate lower and higher wear values than that obtained for erosion and corrosion rates, respectively. Through these results, it was possible to determine an antagonistic effect for AISI 304L stainless steel in industrial tailings slurries. These results are supported by changes in the electrochemical parameters, passive film stability, and morphological attributes.