Abstract:
The corrosion behavior of marine-grade mild steels in seawater environments is a critical
factor influencing the maintenance and longevity of marine structures such as vessels,
offshore platforms, and coastal installations. Despite extensive research in various oceanic
regions, the specific challenges posed by the Bay of Bengal (BoB) have not been fully
explored, particularly for marine-grade steels. These steels, distinct in their alloying elements,
may exhibit unique corrosion behaviors in the BoB's dynamic and chemically complex
environment. This study aims to address this gap by investigating the corrosion behavior of
two types of marine-grade mild steels, Grade A and Grade 907, under both static and
dynamic conditions. The research employed laboratory-based experiments using gravimetric
and electrochemical methods to measure corrosion rates of seamless and welded steel
samples. These samples were immersed in seawater collected from multiple BoB locations,
with exposure times ranging from initial immersion to extended submersion. Additionally,
mechanical testing, including tensile strength and hardness assessments, was conducted to
evaluate the degradation in material properties due to corrosion. Microstructural analysis
using Optical and Scanning Electron Microscopy (SEM) revealed significant changes in the
crystalline structure of the steel samples, indicating the extent of corrosion damage. Results
indicate that dynamic conditions significantly accelerate corrosion rates, especially in deeper
regions of the BoB, where the corrosion activity was higher than in coastal areas. Welded
samples exhibited greater susceptibility to localized corrosion, suggesting a need for
enhanced protective measures in these areas. The mechanical tests revealed a measurable
reduction in hardness and more pronounced corrosion-induced damage in welded joints,
highlighting the need for enhanced protection strategies in these marine areas. These findings
highlight the necessity for region-specific corrosion protection strategies tailored to the
unique environmental conditions of the BoB. By concentrating on the water composition of
the Bay of Bengal, solutions to reduce corrosion in marine-grade mild steels particularly in
this region can be developed. Also, a wider understanding of corrosion behavior in marine
environments will come out.
