Galvanic corrosion behaviors of the low-carbon ferritic stainless steel ERW (electrical resistance welding) joint in the simulated seawater

Abstract

Purpose The purpose of this paper is to focus on the galvanic corrosion behaviors of the low-carbon ferritic stainless steel electrical resistance welding (ERW) joint in the simulated seawater. Design/methodology/approach The electrochemical methods such as electrochemical noise, galvanic current and TOEFL polarization curve tests were used to study the galvanic corrosion behaviors of ERW joints of low-carbon ferritic stainless steel in simulated seawater. On this basis, a reliable accelerated corrosion method was developed. Findings The corrosion type of the base metal and joint is the typical local corrosion. The order of corrosion resistance from strong to weak is: weld zone > base metal > low-temperature heat-affected zone (HAZ) > high-temperature HAZ. The results of constant current-constant potential accelerated corrosion test show that after constant current-constant potential accelerated corrosion, the joints present a typical groove corrosion pattern. The groove initiating area is located in the HAZ, and the corrosion degree in the weld zone is relatively light, which is consistent with the electrochemical test results. Originality/value This paper has clarified the galvanic corrosion behaviors of low-carbon ferritic stainless steel ERW joints. Moreover, a reliable accelerated corrosion method for the low-carbon ferritic stainless steel ERW joint has been developed.