Electrochemical Corrosion Behavior of Spirally-welded API X-70 Line-pipe Steel in Acidic and Salt Media

摘要

The electrochemical behavior of spirally-welded API steel was investigated at ambient temperature in 3.5% NaCl and 1M H_(2)SO_(4) solution using linear polarization and electrochemical impedance spectroscopy (EIS) techniques. In order to reveal the corrosion resistance of different regions within the welded joint some significant characterization parameters in linear polarization and EIS curves were analyzed and compared. The surface morphology of corrosion products was also analyzed by scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS). The results showed that the corrosion resistance of the steel in both solutions at ambient temperature follows the order Weld Metal - Base Metal and HAZ. The corrosion of welded steel in sulfuric acid solution is more than that in NaCl solution.