# A GAN-Augmented Corrosion Prediction Model for Uncoated Steel Plates
## 3 Materials and Methods  
### Dataset  
Our dataset consists of 76 samples, which includes four subsets of corrosion samples collected from four different experiment environments: (1) ISO16539: An accelerated cyclic Test with synthetic ocean water salt-deposition process. (2) PWRI: Combined cyclic corrosion Test, an accelerated corrosion Test developed by Public Works Research Institute. (3) Atmospheric exposure I in Choshi, Japan. (4) Atmospheric exposure II in Miyakojima, Japan. Among them, (1) and (2) are artificial environments, which can accelerate corrosion. In both experiments, we observe the process of corrosion development with three stages. Stage one is 28 days. Stage two is 84 days. Stage three is 168 days. Furthermore, (3) and (4) are normal corrosion in the real environment. The main purpose for involving different experimental environments is to compare corrosion from experiments with real corrosion. Table 1 shows the distribution of 76 samples in each subset (experiment). In each experiment, there are four types of steel plates: SM400A, SM490A, SMA400 AW, and SMA490 AW, equally distributed in every experimental group. SM400A and SM490A are carbon steels, which belong to the JJS G 3106 standard. It corresponds to the international standard ISO 630. SMA400 AW and SMA490 AW are weathering steels, which belong to the JJS G 3114 standard. It corresponds to the international standard ISO 4952. Table 2 shows the detail chemical compositions and mechanical properties of the steels used in the experiments. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Subsets** & **ISO16539** & **PWRI** & \begin{tabular}{c} **Atmospheric** \\ **Exposure I** \\ \end{tabular} & \begin{tabular}{c} **Atmospheric** \\ **Exposure II** \\ \end{tabular} & \
\begin{tabular}{c} **Atmospheric** \\ **Exposure II** \\ \end{tabular} &
\begin{tabular}{c} **Total** \\ **Total** \\ \end{tabular} \\ \hline Number of & 36 & 16 & 12 & 12 & 76 \\ samples & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Corrosion Dataset. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Chemical Compositions (Mass \%)**} & \multicolumn{4}{c}{**Mechanical Properties**} \\ \hline  & **C** & **Si** & **Mn** & **P** & **S** & **Cu** & **Ni** & **Cr** & **Yield Stress** & **Tensile Strength** & **Elongation (\%)** \\ \hline SM400A & 0.18 & 0.17 & 0.5 & 0.015 & 0.006 & - & - & - & 279 & 442 & 29 \\ SM490A & 0.16 & 0.02 & 1.04 & 0.011 & 0.005 & - & - & - & 426 & 542 & 20 \\ SMA400 AW & 0.12 & 0.2 & 0.67 & 0.015 &  
The length, width, and thickness of each plate are 150 mm, 70 mm, and 9 mm. Each plate is wrapped with a 5 mm anti-corrosion tape along all its edges to keep the non-corrosion part at the edges as the reference for the corrosion depth measurement. The back surface of the specimen was covered by the anti-corrosion tape for generating the corrosion from the top surface only. Figure 1 explains the size of each steel plate and the corrosion measurement area in the experiments. We monitor and measure the corrosion depth in a 50 mm \(\times\) 60 mm area in the middle of the steel plate. **ISO16539: An accelerated cyclic Test with synthetic ocean water salt-deposition process. ** ISO16539 [29] is a standard defined by International Organization for Standardization. It defines two accelerated cyclic corrosion Test procedures: Methods A and B, for the evaluation of corrosion behavior of surface-treated metals and their alloys with and without paint on them in atmospheric environments with exposure to synthetic ocean water salt-deposition process and dry/wet conditions at constant absolute humidity. For coated steel structures used in power supply, researchers have verified the correlation between the experimental circumstance and the actual circumstance [30]. Some recent research [31] tries to apply this Test procedure to other industries, such as the auto industry and infrastructure. In this research, we use Method B. Figure 2 illustrates the procedure of our experiment.