In Situ Observations For Corrosion Process At Fusion Boundary Of Cr5Mo Dissimilar Steel Welded Joints In H2S Containing Solution
Cr5Mo异种钢焊接熔合区H2S腐蚀过程的原位观察

The corrosion behaviours of the welded joints between steels Cr5Mo and A302 (Cr25Ni13) in the H2S containing solution (NACE TM-01-77 standard) were studied. In situ SEM observations revealed that compared with other zones the fusion boundary is the worst region for corrosion resistance due to the hydrogen induced disbonding, the corrosion resistance of the post-weld heat-treated joint is worse than that of the as-welded one and the fusion boundary with a broad scale has a stronger resistance for the hydrogen induced disbonding than the narrow one. These variations are related to the inhomogeneous microstructures, carbon diffusion, hydrogen-enrichment and stress concentration around the fusion boundary.