Electrochemical potentiodynamic sweeps and galvanic studies are performed to determine conditions that will initiate localized corrosion in welded areas. The reduction potential and pH in the electrolyte seemed to be essential with respect to where corrosion attacks occur in a welded area of carbon steel. The interpretation of the polarization diagrams for the different parts of the weld showed that they actually had different anodic Tafel slopes and this interpretation could be used to make predictions concerning preferential corrosion behavior. A variance of brine composition causes a change of attacked areas in a weld.