Study on Corrosion Sensitivity of Welded Joints between Dissimilar Metals in Different Environments

In order to study the galvanic corrosion sensitivity of welded joints between dissimilar metals for typical structures of type A EMU in five regional corrosion environment simulation fluids,the ER 309L Si was selected to weld 304 stainless steel and Q345 carbon steel (two dissimilar metals).The weld samples were immersed in solutions simulating the environments of Beijing,Zhengzhou,Wuhan,Guangzhou and Wanning respectively for 120 d.The corrosion rate and corrosion potential of different positions of weld samples were analyzed by electrochemical test after corrosion.After rust removal,the microscopic morphology of the samples was observed and the galvanic effect between the weld and the base metal was analyzed.Results showed that in the simulated solutions of 5 regions,the corrosion rates of the base metal and the weld metal were in the order of Wanning >Guangzhou >Wuhan >Zhengzhou >Beijing.Q345 carbon steel and the weld formed a galvanic pair and the former served as an anode,and the action distance of galvan