Effect of immersion corrosion time on the corrosion performance of welded joints of bimetallic composite pipes

In this study, the corrosion behaviour of X65MS/ N08825 composite pipe welded joints during immersion was investigated using an electrochemical workstation and scanning electrochemical microscopy techniques. When the immersion time was more than 24 h, significant corrosion craters appeared in the weld area, with a maximum depth of 7.05 μm, and the corresponding self-corrosion potentials and self-corrosion current densities were −781 mV and 11.82 μA/cm². When the immersion time was extended to 48 h, the depth of the corrosion crater further increased to 15.23 μm, and the self-corrosion potential and self-corrosion current density were −816 mV and 23.73 μA/cm², respectively.