# A GAN-Augmented Corrosion Prediction Model for Uncoated Steel Plates
## 3 Materials and Methods
### Dataset
Artificial seawater with a concentration of 3.5% was applied to the surface using a spraying device, and a salt deposition of 28.0 \(\pm\) 2.8 g/m\({}^{2}\) was obtained. The repeated drying and wetting process consisted of three hours of dryness (60 \({}^{\circ}\)C, 35%RH) and three hours of wetness (40 \({}^{\circ}\)C, 95%RH), and the transition time from dry to wet and from wet to dry was one hour, which was 8 h per cycle. This was done alternately in 8 cycles (3 days) and 11 cycles (4 days). The corrosion samples are divided into three groups and each group has 3 samples of each type of steel, a total of 36 (\(4\times 3\times 3\)) samples. The three groups have been running experiments for different periods, which are 28 days, 84 days, and 168 days. Figure 1: The size of steel plates and corrosion measure area. **PWRI: A combined cyclic corrosion Test. ** This is an accelerated corrosion Test developed by Public Works Research Institute, which is a developed corrosion procedure widely used in Japan. There are two groups of corrosion experiments and each group has two samples of each type of steel plate. In total there are 16 (\(4\times 2\times 2\)) samples. The first group runs for 28 days of the experiment and the second group runs for 84 days of the experiment. Figure 3 shows the organization of 16 steel plates. Figure 4 shows the procedure of the experiment. One complete cycle takes 24 h. It consists of one hour of wetness (30 \({}^{\circ}\)C, 95%RH), two hours of surface spraying with saltwater (30 \({}^{\circ}\)C, 5%NaClaq), six repetitions of one and half hours wetness (50 \({}^{\circ}\)C, 95%RH), one and half hours of dryness (50 \({}^{\circ}\)C, 20%RH), and another one and half hours of dryness (30 \({}^{\circ}\)C, 20%RH). Figure 3: Organization of steel plates in PWRI. Figure 2: The procedure of seawater spray experiment ISO16539. **Atmospheric exposure I:** This experiment is conducted in Choshi, Japan. The experiment runs for 365 days under the real atmospheric exposure environment. With three samples of each type of steel plate, there are 12 samples in total. **Atmospheric exposure II:** This experiment is conducted in Miyakojima, Japan. The experiment runs for 180 days under the real atmospheric exposure environment. With three samples of each type of steel plate, there are 12 samples in total. For the real corrosion environment, the direct exposure corrosion Test was conducted at the Japan Weathering Test Center. One of the sites is the Miyakojima Exposure Experiment Research Center (24\({}^{\circ}\)44\({}^{\prime}\) N, 125\({}^{\circ}\)9\({}^{\prime}\) E), 2 km from the nearest seashore and 50.0 m high. As the marine subtropical climate, the environment in this area is harsh, with high temperature, high humidity, abundant solar radiation, and many sea salt particles and other degradation factors. Another location is the Choshi Exposure Experiment Research Center (35\({}^{\circ}\)43\({}^{\prime}\) N, 140\({}^{\circ}\)45\({}^{\prime}\) E), 4 km from the nearest seashore, and at an altitude of 53.6 m above sea level. This location is a normal corrosive environment. The two sites represent both harsh and normal corrosive environments. Figure 5 explains how the steel plates are organized in both atmospheric exposure experiments.