Effect of Surface Condition of Welded Joint of 304L Stainless Steel on Its Corrosion Behavior in Boric Acid Solution

The effect of surface condition of the welded joint of 304L stainless steel on its corrosion behavior in boric acid solution was studied by immersion corrosion testing,electrochemistry testing, optical microscopy, scanning electron microscopy (SEM) and 3D morphology testing. The results show that the corrosion resistance of the 304L stainless steel welded joint in boric acid solution was improved by sanding. The welded joint sanded with No. 2000 sandpaper had a stable corrosion rate throughout the immersion process, and the corrosion rate was far lower than that of the unsanded welded joint. The surface roughness of the welded joint after being sanded with No. 40 sandpaper was much larger than that of the mechanically polished joint, but the former had a lower corrosion potential than the latter, which means that the smaller the surface roughness is, the better the corrosion resistance is.