Corrosion performance and microstructure of a Q370qENH weathering steel welded joint treated by the laser surface remelting method

In this research, the laser surface remelting (LSR) method was utilized to treat the weld joint of Q370qENH weathering steel. A heterogeneous structure with superficial fine grains formed after LSR. The remelted joint demonstrated a 97.2 % increase in electrochemical impedance value, rising from 1424 Ω to 2808 Ω compared to the welded joint, indicating improved corrosion resistance. The enhanced corrosion resistance can be attributed to the reduction of grain size, which facilitates the diffusion of Fe on the surface and encourages the formation of passivated films. These findings are significant for extending the service life and expanding the application scope of weathering steel structural parts.