The Corrosion Resistant Performance of Marine Grade Aluminum Sheets
Seawater is a strong corrosive medium with high salinity, which has a strong corrosive effect on general metals. For a long time, people often choose titanium and copper-nickel alloys as seawater corrosion-resistant materials.
Titanium has high corrosion resistance, but has poor thermal conductivity, high price and is not easy to process. Copper-nickel alloys are prone to contact electrochemical corrosion. Aluminum and aluminum alloys are of light wight, high strength, high thermal efficiency, and moderate price. 5xxx marine grade aluminum sheets has good seawater corrosion resistance. among which 5454 and marine grade 5052 are represented.
Chemical Composition
Alloy | Mg | Mn | Cr |
5454 | 2.4-3.0 | 0.5-1.0 | 0.05-0.20 |
5052 | 2.2-2.8 | 0.15-0.30 |
The Corrosion Resistant Performance
Alloy | Corrosion rate | Standard electrical level potential | Mechanical properties Tensile strength |
5454 | 0.0802 | -0.86 | 250-270 |
5052 | 0.048 | -0.85 | 195-230 |
The Cons of 5454 and 5052 alloys:
a. There is a phenomenon of "aging softening". The mechanical properties of 5454 and 5052 alloys will decrease with the extension of time during use.
b. b. There is a tendency of stress corrosion cracking. In the process of hot working and cold working, there is internal stress in the product, and the existence of internal stress accelerates stress corrosion.
c. There is a tendency to crack during welding. During welding, micro cracks are generated in the weld due to the local melting between the crystals, which is easy to cause the weld to crack.
For better corrosion resistance, on the basis of 5083 aluminum alloy, 5383 aluminum is developed by reducing the content of Fe and Si impurities, slightly increasing the content of Cu and Zn, and adding a small amount of Zr.
It has higher strength and better welding performance. With higher hardness, the number of welded boats has been greatly reduced. Therefore, it is much favored by large high-speed ships manufacturers. Welcome to leave message below to inquire what you need.
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