Metal welding - Fig. 2-CRS-3 welding sample was exposed to the sun, and the macro morphology and corrosion steps after pickling were taken back. Through CO2 gas shielded welding (250A, 29V, 300mm / min, 14.5 kJ / cm).
It can be seen from the figure that reddish brown corrosion product spots are distributed on the substrate of crs-3 steel 2-month rust layer sample, which are also less distributed on the sunny side, and the distribution is not very uniform. The back surface is evenly distributed on the substrate with more corrosion spots. There are gray corrosion products distributed on the substrate of 1-year rust layer samples, which are light in color and evenly distributed on the substrate. This may also be related to the protective effect of corrosion products produced by long-time exposure on the substrate. The color of rust layer samples in two years is deeper, and the distribution of rust layer is denser than that in the first two periods. After removing the corrosion products, the surface of the welded joint is gray. It can be seen from the figure that there are color differences and corrosion differences between the base metal area and the weld area after removing the corrosion products. The color of the weld area is deeper, but the color difference between the two is not obvious, indicating that the welded joint has good corrosion resistance matching. For the one-year sample, there is no step between the weld zone and the base metal zone, and the step height between the weld zone and the base metal zone is basically the same, which indicates that there is little difference in corrosion resistance between the weld zone and the base metal zone; For 2-year specimens, the height of base metal zone and weld zone is basically the same, and there is no obvious corrosion step, indicating that the corrosion resistance of weld metal is consistent with that of base metal.
