京广线高铁电气柜Q345碳钢涂层体系环境谱寿命预测

Environmental spectrum life prediction of Q345 carbon steel coating electrical cabinet of Beijing-Guangzhou high speed railway

对京广线高速铁路电气柜Q345碳钢涂层体系服役环境进行加速腐蚀和老化试验,研究了涂层体系加速腐蚀试验过程中的失效行为。参照相关国家标准对完整涂层的基本性能进行测试,利用电化学交流阻抗测试和膜下腐蚀分析方法对涂层破损进行研究,采用电子显微镜结合能谱仪对Q345碳钢基材腐蚀形貌和成分分析发现,5个试验周期内,完整涂层的附着力、光泽度、硬度等基本性能指标均没有明显变化,表明涂层对基体的保护性能非常好,而Q345碳钢在相同环境下的腐蚀速率非常快,且锈层对基体的保护作用很弱;划叉试样在试验过程中膜下腐蚀扩展面积和涂层翘起高度有明显增加,且均在第四周期开始。因此京广线高铁电气柜在服役期限内涂层对Q345碳钢的保护是必要且关键的,而当涂层发生破损时,必须及时对其进行修复处理,避免破坏的面积和深度进一步增大。

Accelerated corrosion and aging test of the electrical cabinet Q345 carbon coating steel material of the Beijing-Guangzhou 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.