Ship structure is mostly used in harsh seawater medium and marine environment, so whether aluminum alloy is corrosion resistant is one of the main signs that determine whether it can be used as marine aluminum alloy. General requirements for marine aluminum alloy substrates and welded joints in seawater and marine environments without stress corrosion, flaking corrosion and intergranular corrosion tendency; try to avoid contact corrosion, crevice corrosion and sea creatures adhesion corrosion; allow small uniform corrosion and spots corrosion.
Experience shows that any kind of small aluminum vessel can be used for decades without suffering any obvious corrosion. The decommissioning of such ships is usually due to technical obsolescence, not the aging of aluminum structures. In general, the 5 series and 6 series aluminum-magnesium alloys have excellent marine weather resistance, especially seawater erosion resistance has been recognized by everyone. Among them, the 5083 aluminum plate is a typical aluminum alloy for welding. It has the highest strength among non-heat-treated alloys, good weldability, corrosion resistance and low temperature performance. It can be used as a marine aluminum plate on the ship side.