Effect of Welding Materials on Corrosion Resistance of Q355NH Steel Arc Welding Structure

J422, J506 and J506CrNiCu electrodes were used for the welding of Q355NH weathering steel, respectively, and the corrosion characteristics and mechanical properties change of Q355NH welding structure under accelerated corrosion conditions were studied. Scanning Kelvin probe and laser confocal microscope combined with microscopic characterization, the corrosion difference of different weld samples was explored, and the 500 h and 1000 h accelerated corrosion characteristics of welding zone and base metal as well as the influence on the residual mechanical properties were studied.The results show that galvanic corrosion is easy to happen in the joints of J422 and J506 electrodes, thus thinning occurs preferentially in the weld zone.Moreover, the local corrosion of the J506 weld is more serious due to uneven microstructure.The potential difference between J506CrNiCu electrode and Q355NH matrix is small and the growth mechanism of the rust layer is similar, which can realize synchronous thinning of welding zone and base metal, and it is not easy to cause stress concentration in service. In the tensile test of corroded joints, the tensile strength indexes are lower than those before welding, which is related to that the measured cross section area of the joint is higher than the actual cross section area.