Corrosion resistance comparison of S355J2G3 steel welded joint and Q345R low alloy steel

S355J2G3 steel is a European standard steel with the composition of C ≤0.20, Si≤0.55, Mn ≤1.60, P≤0.035, S≤0.035.
S355J2G3 is a low-alloy high-strength structural steel, and S355J2G3 is roughly equivalent to GB's Q345D. S355J2G3, J2G3 means that the delivery state is normalized, the impact energy at -20°C is 27J, and G3 and G4 mean the deoxidation method.

The corrosion rate of S355J2G3 steel welded joint is lower than that of Q345R steel welded joint, and the corrosion resistance of S355J2G3 steel welded joint is better than that of Q345R steel welded joint.

The surface of the Q345R steel welded joint is attached with an orange-red loose pit-like rust layer. The surface of the S355J2G3 steel welded joint also has an orange-red rust layer at the initial stage. denser.

The structure of corrosion products of Q345R steel welded joints is mainly block and powder, and the shape is irregular. At the same time, there are cracks and gaps in the rust layer; the corrosion products of S355J2G3 steel welded joints are block and needle.