Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding

authored by
Leandro Vaccari, Thomas Scheithauer, Ivan Lendiel, Jan Klett, Thomas Hassel, Hans Jürgen Maier
Abstract

Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.

Organisation(s)
Institute of Materials Science
Type
Article
Journal
npj Materials Degradation
Volume
8
No. of pages
11
Publication date
11.05.2024
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Ceramics and Composites, Chemistry (miscellaneous), Materials Science (miscellaneous), Materials Chemistry
Sustainable Development Goals
SDG 14 - Life Below Water
Electronic version(s)
https://doi.org/10.1038/s41529-024-00471-9 (Access: Open)