Corrosion behavior of welded joint in oil transportation pipeline, a review

Abstract

In This review the corrosion behavior of welded joints areas are discussed, which are critical to pipeline structural safety because they more susceptible to deterioration than the base material due to changes in microstructure, chemical composition, and residual stresses introduced during the welding process. The paper discusses the main factors influencing corrosion in welded joints, including the impact of environmental conditions such as saline soil and also microbiological factors, many forms of corrosion could be formed such as pitting corrosion, stress corrosion cracking (SCC) dissimilar corrosion (galvanic corrosion). This study focused on heat effected zone (HAZ) to understand the effect of metal properties changes after welding process. Finally main protection methods were covered, including post-weld treatments (PWHT), protective coatings, and cathodic protection (CP). The aim of this study is to improve pipeline design, operation, and maintenance procedures in order to achievement long term operation lifetime, increase safety and lowering the maintenance cost of oil and gas pipeline. The results conclude that research and development in welding process and corrosion prevention should be continued.