https://doi.org/10.3221/IGF-ESIS.78.11
Marine chains operate under corrosive and impact-prone conditions, yet the combined influence of seawater exposure, notch condition and test temperature on their impact toughness remains insufficiently clarified. This study addresses this gap by examining the Charpy V-notch impact response of AISI 1008 steel extracted from galvanized marine chain links after exposure to seawater and substitute seawater. Rather than treating corrosion damage only as mass loss, the study focuses on how corrosion history, notch timing and local material variability jointly affect absorbed impact energy. The results showed a pronounced temperature sensitivity in the uncorroded condition, with absorbed energy decreasing sharply from room temperature to sub-zero temperatures. After 30 days of immersion, both seawater and substitute seawater reduced the average impact energy at 0 °C, while seawater produced higher mass loss. However, the absorbed energy did not scale directly with corrosion loss. Considerable scatter was observed even under nominally identical conditions. Near-fracture cross-sectional SEM highlighted local ferrite–pearlite heterogeneity and discontinuity-like features in selected regions. The findings demonstrate that the impact resistance of the investigated marine chain steel cannot be assessed solely from average corrosion loss or hardness values, and highlight the need to consider notch condition, temperature and microstructural variability in structural integrity evaluations.
