Metallurgical Aspects of Marine Welding

This chapter focuses on the metallurgical principles underlying marine welding, connecting process parameters with material behavior and weld quality. It begins with an overview of the heat-affected zone (HAZ) and the microstructural transformations occurring in steels, aluminum, and stainless steels during welding. Detailed attention is given to the influence of cooling rate, preheating, and alloy composition on phase formation, hardness, and toughness. The discussion then extends to the weldability of high-strength steels and corrosion-resistant alloys, emphasizing metallurgical control to prevent cracking and degradation. Special sections address hydrogen-induced cracking (HIC) and stress corrosion cracking (SCC), two major issues affecting the reliability of marine welds. The mechanisms, sources, and preventive strategies for these phenomena are thoroughly explored. The chapter concludes with coverage of metallurgical testing methods such as microstructural analysis, hardness mapping, and corrosion testing in simulated seawater conditions. By bridging theory and practice, this chapter underscores the metallurgical science that governs mechanical performance and corrosion resistance in marine welding, empowering engineers to design robust, defect-free joints under demanding service environments.