scholarly journals Analysis of Environmental Factors Affecting the Atmospheric Corrosion Rate of Low-Alloy Steel Using Random Forest-Based Models

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3266 ◽  
Author(s):  
Luchun Yan ◽  
Yupeng Diao ◽  
Kewei Gao
Keyword(s):  
Random Forest ◽  
Environmental Factors ◽  
Corrosion Rate ◽  
Alloy Steel ◽  
Atmospheric Corrosion ◽  
Test Site ◽  
Training Data ◽  
Low Alloy Steel ◽  
Exposure Test ◽  
Corrosion Data

As one of the factors (e.g., material properties, surface quality, etc.) influencing the corrosion processes, researchers have always been exploring the role of environmental factors to understand the mechanism of atmospheric corrosion. This study proposes a random forest algorithm-based modeling method that successfully maps both the steel’s chemical composition and environmental factors to the corrosion rate of low-alloy steel under the corresponding environmental conditions. Using the random forest models based on the corrosion data of three different atmospheric environments, the environmental factors were proved to have different importance sequence in determining the environmental corrosivity of open and sheltered exposure test conditions. For each exposure test site, the importance of environmental features to the corrosion rate is also ranked and analyzed. Additionally, the feasibility of the random forest model to predict the corrosion rate of steel samples in the new environment is also demonstrated. The volume and representativeness of the corrosion data in the training data are considered to be the critical factors in determining its prediction performance. The above results prove that machine learning provides a useful tool for the analysis of atmospheric corrosion mechanisms and the evaluation of corrosion resistance.

scholarly journals Maps estimates of atmospheric corrosion of low alloy steel in Costa Rica

2015 ◽  
Vol 7 (2) ◽  
pp. 181-191
Author(s):  
Javier Rodríguez Yáñez ◽  
Luis Garita Arce ◽  
Ericka Saborío Leiva
Keyword(s):  
Costa Rica ◽  
Alloy Steel ◽  
Atmospheric Corrosion ◽  
Climatic Data ◽  
Local Models ◽  
Low Alloy Steel ◽  
Atmospheric Parameters ◽  
Corrosion Rates ◽  
Wetting Time ◽  
Low Levels

The Corrosion maps used are to display quickly the different situations in a country. These maps developed are for low alloy steel in Costa Rica depending on climatic data and pollutant levels, considering the different regulations associated with ISO 9223 and models developed by the Center for Research in Corrosion (CICorr). The atmosphere in Costa Rica has high rates of Brooks, considered very corrosive. The corrosion controlling atmospheric parameters are the relative humidity (RH) and Wetting Time (TWH) associated with low levels of pollution and rural type atmospheres. The corrosion rates are between 25 and 80μm*yr-1 (Class 3 and 4 according to ISO 9223). Local models associated with the controlling parameters are more suitable for estimating the corrosion according to ISO 9223.

Corrosion behaviors of weathering steel 09CuPCrNi welded joints in simulated marine atmospheric environment

2016 ◽  
Vol 63 (4) ◽  
pp. 295-300 ◽  
Author(s):  
Lihua Gong ◽  
Qing Xing ◽  
Huihuang Wang
Keyword(s):  
Corrosion Rate ◽  
Base Metal ◽  
Welded Joints ◽  
Atmospheric Corrosion ◽  
Atmospheric Environment ◽  
Weathering Steel ◽  
Low Alloy Steel ◽  
Rust Layer ◽  
Content Type ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to investigate the effect of welding procedure on the corrosion behaviors of weathering steel 09CuPCrNi in marine atmospheric environment. The corrosion processes of weathering steel 09CuPCrNi and its welded joints in marine atmospheric environment were simulated by a salt spray dry-wet test. Design/methodology/approach The corrosion behaviors of the base metal and the welded joints at corrosion times of 2, 4, 8, 12, 24 weeks were investigated by weight loss test, electrochemical techniques, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). The corrosion rates, as well as the morphologies and electrochemical characteristics of corrosion products, the distribution of major alloying elements in rust layer were obtained. The influence of welding on the atmospheric corrosion of 09CuPCrNi was studied. Findings The results indicate that the corrosion rate of the 09CuPCrNi welded joints decreases gradually with the corrosion time, and the major alloying elements are enriched in the inner rust layer, which are similar to that of the base metal. In the early stage during the corrosion process, the welded joints with inhomogeneous structure show the poorer corrosion resistance than that of the base metal. However, it looks the opposite way around in the late corrosion stage, when the uniform corrosion products with even thickness of the base metal tend to detach from the substrate easier and earlier and resulting in cracks, which increase the corrosion rate comparatively with that of the welded joints. Originality/value 09CuPCrNi low alloy steel is a kind of typical weathering steel developed in China which is similar to Corten A developed by USA. Nowadays, 09CuPCrNi low alloy steel is widely adopted in many fields which require welding processes. In the past years, the research of weathering steel welded joints was mainly concentrated on the strength, toughness and weldability. Less work has been done to investigate the difference of corrosion evolution and characteristics between the base metal and its welded joints. Thus, the main objective of the present work was to analyze the influence of welding on the atmospheric corrosion.

scholarly journals Numerical Simulation of Galvanic Corrosion between Carbon Steel and Low Alloy Steel in a Bolted Joint

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Rachid Radouani ◽  
Younes Echcharqy ◽  
Mohamed Essahli
Keyword(s):  
Numerical Simulation ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Alloy Steel ◽  
Contact Area ◽  
Galvanic Corrosion ◽  
Research Work ◽  
Steel Structures ◽  
Low Alloy Steel ◽  
End Plate

The galvanic corrosion of a bolt joint combining carbon steel end plate and low alloy steel bolt was investigated electrochemically in a 1 M HCl solution. The corrosion parameters of the joint components were used for numerical simulation using Comsol Multiphysics software to analyze the galvanic corrosion behavior at the contact zone between the head bolt and the end plate. In this research work we evaluate the variation of the corrosion rate in the steel end plate considered as the anode, in order to determine the lifetime of the bolted assembly used in steel structures. Three materials (20MnCr5, 42CrMo4, and 32CrMoV13) and three bolts (M12, M16, and M20) were tested in two thicknesses of electrolyte 1 M HCl (e = 1 mm, e = 20 mm). It is found that the corrosion rate of the anode part (end plate) is higher for 32CrMoV13 materials and it increases if both diameter of the bolt and thickness of the electrolyte increase (Cr(M20) > Cr(M16) > Cr(M12) and Cr(e = 20 mm) > Cr(e = 1 mm)). This corrosion rate is higher in the contact area between the bolt head and the end plate, and it decreases if we move away from this contact area.

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