Accelerated corrosion and aging test of the electrical cabinet Q345 carbon coating steel material of the BeijingGuangzhou line EMUs was carried out in the relevant service environment, and the failure behavior of the coating system during the test was studied. Referring to the relevant national standards to test the basic performance of the complete coating, this test adopted the electrochemical impedance test and the corrosion analysis method under the film to study the damage of the coating. Electron microscope and energy spectrum analysis were used to analyze the corrosion morphology and composition of Q345 carbon steel substrate. The results showed that the basic performance indicators such as adhesion, gloss and hardness of the complete coating did not change significantly during the five test periods, indicating the coating's very good protective performance on the substrate. Contrarily, the Q345 carbon steel's corrosion rate is very fast in the same environment, and the protective effect of the rust layer on the substrate is very weak. During the cross-cutting test, both the corrosion expansion area under the film and the coating lift height increased significantly at the beginning of the fourth period. Therefore, the coating of the electrical cabinet of the Beijing-Guangzhou line EMUs is necessary and critical to the protection of Q345 carbon steel during its service period. When the coating is damaged, it must be repaired in time to prevent the damaged area and depth from further increasing.

high speed railway electrical cabinet  /  Q345 carbon steel coating system  /  Q345 carbon steed corrosion  /  failure analysis