Marine grade aluminum includes 5052 (5A02), 5252, 5154, 5454, 5754, 5083, 5086, 5059, 7A33 alloy, etc. Alloy 5052 has lower magnesium content; alloys 5154, 5454, and 5754 have slightly lower magnesium content; alloy 5083 has slightly higher magnesium content; alloy 5086 has slightly lower magnesium content; and alloy 5059 has the highest magnesium content.

From the Al-Mg binary phase diagram, it can be seen that the solid solubility of Mg in Al is second only to that of Zn, with a limit solubility of 17.4% at 470 degree and only about 1% at room temperature. Theoretically, Al-Mg alloys should have strong age hardening effect, but the solid phase (Al3Mg2) is limited by the tendency of crystal precipitation and dispersion. This hardening has no practical value, so the Al-Mg alloys are all annealed. The service state (O) and the cold work hardening state (H), as we often say, are a deformed aluminum alloy that cannot be strengthened by heat treatment.

Marine Grade Aluminum 8

In the chemical composition of Marine Grade Aluminum aluminum-magnesium alloy, the maximum magnesium content of 5052 alloy with low magnesium content is only 2.8%, and the content of 5083 alloy with the highest magnesium content is 4.9%. Although the strength properties of the alloy are improved due to the increase of Mg content, the plasticity and corrosion resistance properties are significantly reduced. Especially for alloys with Mg>6%, the process plasticity is particularly strong.

Aluminum-magnesium alloy is one of the most widely used wrought aluminum alloys. It is characterized by a lower density than aluminum. It has excellent resistance to marine climate and seawater corrosion, weldability and polishability, and excellent plasticity (Mg Less than or equal to 5%). ), also has good seismic performance, and the fatigue strength is greater than that of duralumin.

Marine Grade Aluminum 5

Since Al-Mg alloy has only negligible age hardening and strong intergranular tendency, it can only be used for annealing (305℃～360℃) or cold working. However, the excellent corrosion resistance of Al-Mg alloys can only be exhibited when the β phase is uniformly distributed along the grains and grain boundaries, and the distribution state is closely related to the Mg content. Studies have shown that the 5052 type alloy with Mg≤3.0% is extremely stable whether it is annealed or cold worked (O, H), heated at room temperature or stabilized (sensitized) temperature (67℃～177℃). Intergranular β-phase network film is not formed for a long time, and it is not sensitive to stress corrosion cracking (SCC) and exfoliation corrosion (EFC). However, after Mg>3.5%, especially the cold-worked sheet, although the Mg content is increased (>5% Mg), the susceptibility to SCC is also greatly increased, even at room temperature for a long time (20a~30a), along the The grain boundary forms a continuous β-phase network film. Because the high Mg (>6%) alloy is completely annealed even at 315 degree -330 degree , the solid solution cannot be completely decomposed and is still in a supersaturated state, so the structure is very unstable.

Marine Grade Aluminum 3

Measures to improve the microstructure stability of high magnesium alloys: First, large cold deformation (20%~50%) after annealing, increase dislocation density and phase formation nucleation point, annealing at 200 degree promotes full decomposition and uniform distribution of solid solution in the beta phase. As long as the precipitation of phase along the crystal phase is eliminated, the anti-exfoliation corrosion performance can be significantly improved; on the contrary, when the cold deformation is less than or equal to 30% and the annealing temperature is less than 200 degree , the crystal structure along the crystal lattice is preserved, that is, the stress corrosion cracking sensitivity is, Because the potential of the beta phase is lower than -1.10 V -0.9 V in an alpha solid solution (4% Mg alloy) multiplied by 0.2 V, it acts as an anode and tends to preferentially dissolve along the beta-retinal membrane. The microstructure of the analyzed (precipitated) Al-Mg alloy is composed of uniformly dispersed -phase particles and subgrains, which has a certain substructure strengthening effect; the second is to reduce the magnesium content to Less than or equal to 3%, and add an appropriate amount of Mn and Cr can not only improve the strength, but also increase the recrystallization temperature, and also avoid the precipitation of phase along the crystal, and obtain the strength equivalent to that of high-strength alloys. magnesium alloy. Alloy 5454 is one such alloy. Its tensile strength is equal to that of Al-4Mg alloy, and there is no stress corrosion cracking and exfoliation corrosion susceptibility, but this method does not greatly improve the strength of Al-Mg. And it has a certain substructure strengthening effect; the second is to reduce the magnesium content to Less than or equal to 3%, and add an appropriate amount of Mn and Cr, which can not only improve the strength, but also increase the recrystallization temperature, and also avoid the precipitation of phase along the crystal, and obtain high Strength equivalent to the strength of the alloy. magnesium alloy. Alloy 5454 is one such alloy. Its tensile strength is equal to that of Al-4Mg alloy, and there is no stress corrosion cracking and exfoliation corrosion susceptibility, but this method does not greatly improve the strength of Al-Mg. And it has a certain substructure strengthening effect; the second is to reduce the magnesium content to Less than or equal to 3%, and add an appropriate amount of Mn and Cr, which can not only improve the strength, but also increase the recrystallization temperature, and also avoid the precipitation of phase along the crystal, and obtain high Strength equivalent to the strength of the alloy. magnesium alloy. Alloy 5454 is one such alloy. Its tensile strength is equal to that of Al-4Mg alloy, and there is no stress corrosion cracking and exfoliation corrosion susceptibility, but this method does not greatly improve the strength of Al-Mg. And obtain strength comparable to high magnesium alloys. Alloy 5454 is one such alloy. Its tensile strength is equal to that of Al-4Mg alloy, and there is no stress corrosion cracking and exfoliation corrosion susceptibility, but this method does not greatly improve the strength of Al-Mg. And obtain strength comparable to high magnesium alloys. Alloy 5454 is one such alloy. Its tensile strength is equal to that of Al-4Mg alloy, and there is no stress corrosion cracking and exfoliation corrosion susceptibility, but this method does not greatly improve the strength of Al-Mg.