CORROSION BEHAVIOR OF HRB 400 REINFORCING STEEL WELDING JOINT IN SIMULATED CONCERT ENVIRONMENT BASED ON SVET

Abstract

Based on SVET technology, the corrosion tendency of HRB400 steel welded joint and its base metal in simulated concrete environment and the influence of corrosion products were studied in this paper. The results show that the microstructure of the weld metal and base metal are ferrite+pearlite, and the microstructure of the heat affected zone is incompletely transformed bainite+ferrite+pearlite. Since the region produces smaller grains and more grain boundaries after welding, it becomes the most prone area for corrosion of welded joints. The addition of Cl– inhibited the passivation of HRB400 steel welded joint in the simulated concrete pore fluid. Through the analysis of Nyquist curve and polarization curve, it was found that under high chloride ion concentration, the base metal is more sensitive to chloride ions compared to welded joints.With the increase of Cl– concentration, the current density in the welded joint area gradually increased, but after reaching the chloride concentration of 0.5 mol/L, the current density tended to be flat. The occurrence of this phenomenon confirms the above conclusion. Further more,through SVET testing of the filler metal, it can be found that the filler metal has good adaptability to the HRB400 welding joint, forming a welding joint with better performance.