With its distinct composition design (magnesium content 2.2-2.8%, chromium content 0.15-0.35%), 5052 aluminum sheet, a common Al-Mg rust-proof aluminum, has demonstrated exceptional adaptability in the field of ships. Its main benefits are:
Seawater corrosion-resistant: magnesium creates a thick oxide layer, chromium prevents intergranular corrosion, and it can survive rigorous testing in a salt spray environment (5% sodium chloride solution, 35°C) for 6–18 days.
Lightweight properties: With a density of just 2.72 g/cm³, it is 60% lighter than steel, greatly increasing ships' fuel efficiency.
Tensile strength 170-305 MPa, yield strength ≥65 MPa, and elastic modulus 69.3-70.7 GPa provide medium strength and high toughness, making them appropriate for medium-load applications like hull structures, decks, cabin bulkheads, etc.
Mechanical properties
Rigidity and toughness are both considered in the mechanical performance of 5052 marine-grade aluminum:
Tensile strength: 230 MPa in the cold-work-hardened state (H34) and 170 MPa in the annealed state (O), satisfying the strength specifications of hull structural components.
Better than 6061 aluminum alloy in terms of fatigue resistance, this material is appropriate for ship components that are regularly hit by waves.
Formability: 5052-O aluminum sheet retains its shape stability even after deep drawing, bending, and other intricate processing.
Corrosion resistance
The alloy's composition and microstructure give 5052 its resistance to corrosion:
Passivation film protection: superior to 3003, 6061, and other alloys due to its high magnesium content, naturally occurring AlO₃-MgO composite oxide film, and resistance to salt spray.
Chromium plays a part in preventing intergranular corrosion and preserving resistance to stress corrosion cracking (SCC) following welding.
Comparative test: 5052's corrosion rate in the salt spray test is roughly 0.05 mm/year, which is superior to 6061's 0.12 mm/year and comparable to 5083's 0.03 mm/year.
Suggestions for applications:
Long-term exposed parts (like hull plates) should be anodized or coated to prevent corrosion.
When it comes into contact with steel, insulating gaskets should be used to stop galvanic corrosion.
Welding properties
Although the performance of 5052 aluminum welding is good, the following points should be noted:
Method of welding
TIG welding is advised for thin plates (≤6 mm), with argon gas flow rates of 10-15 L/min and currents ranging from 80 to 150 A. The welding area is tiny and has a lovely weld.
With a current of 150–250 A and a mixed gas (75% Ar + 25% He) to enhance penetration, MIG welding is appropriate for medium and thick plates (≥6 mm).
High efficiency and minimal deformation are features of laser welding. It must regulate the welding speed (2–5 m/min) and power (2–4 kW).
Selection of welding wire
Strong adaptability, excellent corrosion resistance, and weld strength near the base material are characteristics of ER5356 (Mg 5%).
The weld tensile strength of ER5183 (Mg 4.5%) can reach 250MPa, making it appropriate for high-stress components.
Treatment after welding
To remove the oxide scale and restore corrosion resistance, the weld must be pickled (10% HNO₃+3% HF) and then anodized (150 g/L, 18 V sulfuric acid concentration).
It is advised to apply chromate conversion film before painting directly on the weld area.
In addition to marine-grade aluminum sheets, GNEE Aluminum also sells aluminum welding wire. Feel free to ask us what you need.
