The primary methods are TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding. TIG offers precise control for thin sheets and critical joints, while MIG is faster for thicker sections or large-scale projects. Both methods use inert gas shielding (argon/helium) to prevent oxidation, ensuring strong, corrosion-resistant welds essential for marine environments.
Aluminum forms an oxide layer that melts at a higher temperature than the base metal, risking incomplete fusion. Pre-cleaning with solvents or stainless steel brushes removes oxides, oils, and contaminants, ensuring proper weld penetration and reducing defects like porosity or cracking.
5083 alloy (magnesium-rich) is highly weldable and corrosion-resistant, ideal for hulls. 6061 alloy (magnesium-silicon) is stronger but prone to hot cracking; it requires precise heat control and filler metals like 4043 or 5356 to mitigate cracking risks. Matching filler material to the alloy is crucial for durability.
Thick sections (e.g., over 6mm) risk incomplete penetration and distortion due to aluminum's high thermal conductivity. Solutions include:
Preheating (150–250°C) to reduce thermal shock.
Multi-pass welding with controlled heat input.
Using pulsed MIG/TIG to manage heat distribution.
Key practices include:
Post-weld cleaning to remove slag and oxide residues.
Applying corrosion-resistant coatings (e.g., zinc-rich primers, anodizing).
Using compatible filler alloys to avoid galvanic corrosion.
Ensuring full penetration to eliminate crevices where moisture can accumulate.
