Characteristics of 3××× series alloy aluminum plate

3003 aluminum alloy is an AL-Mn alloy, which is the most widely used anti-rust aluminum. The strength of this alloy is not high (slightly higher than that of industrial pure aluminum) and cannot be strengthened by heat treatment. Therefore, cold working methods are used to improve its mechanical properties. Properties: High plasticity in annealed state, good plasticity in semi-cold work hardening, low plasticity in cold work hardening, good corrosion resistance, good weldability, and poor machinability. Mainly used for low-load parts that require high plasticity and good weldability, working in liquid or gas media, such as fuel tanks, gasoline or lubricating oil conduits, various liquid containers and other small-load parts made by deep drawing, Wire is used to make rivets.

The application of 3004 aluminum alloy strip is widely used in decoration, packaging, construction, transportation, electronics, aviation, aerospace, weapons and other industries. Aluminum is used in aircraft skins, fuselage frames, etc.

The role of alloying elements and impurity elements in 3××× series alloy aluminum sheets

1. Mn: Mn is the only main alloying element in the 3××× series alloy aluminum plate, and its content is generally in the range of 1.0% to 1.6%. The strength, plasticity and process performance of the alloy are good, and Mn and Al can form MnAl6 phase. The strength of the alloy increases with the increase of Mn content. When the Mn content is higher than 1.6%, the strength of the alloy increases. However, due to the formation of a large amount of brittle compound MnAl6, the alloy is easy to crack when deformed. With the increase of Mn content, the recrystallization temperature of the alloy increases correspondingly. Due to the great supercooling ability of this series of alloys, large intragranular segregation occurs during rapid cooling and crystallization. The concentration of Mn is low in the center of the dendrite and high in the edge. When Mn is segregated, it is easy to form coarse grains after annealing.
2. Fe: Fe can dissolve in MnAl6 to form (FeMn)Al6 compound, thereby reducing the solubility of Mn in Al. 0.4%~0.7% Fe is added to the alloy, but Fe+Mn should not be more than 1.85%, which can effectively refine the grains of the plate after annealing. Otherwise, a large number of coarse flake (FeMn) Al6 compounds will be formed, which will Significantly reduce the mechanical properties and process properties of the alloy.
3. Si: Si is a harmful impurity. Si and Mn form a complex ternary phase T (Al12Mn3Si2), which can also dissolve Fe to form a (AlFeMnSi) quaternary phase. If Fe and Si in the alloy exist at the same time, the α (Al12Mn3Si2) or β (Al9 Fe 2Si2) phase will be formed first, which destroys the strong influence of Fe, so the Si in the alloy should be controlled below 0.6%. Si can also reduce the solubility of Mn in Al, and the effect is greater than that of Fe. Fe and Si can accelerate the decomposition process of Mn from supersaturated solid-liquid during hot deformation, and can also reduce some mechanical properties.
4. Mg: A small amount of Mg (≈0.33%) can significantly refine the annealed grains of this alloy and slightly increase its tensile strength, but it also damages the surface gloss of the annealed material. Mg can also be an alloying element in Al-Mg alloys. Adding 0.3% to 1.3% Mg increases the strength of the alloy and reduces the elongation (annealed state), so Al-Mg-Mn alloys are developed.
5. Cu: The alloy contains 0.05%~0.5% Cu, which can significantly improve its tensile strength. However, containing a small amount of Cu (0.1%) can reduce the corrosion resistance of the alloy, so the Cu content in the alloy should be controlled below 0.2%.
6. Zn: When the Zn content is less than 0.5%, it has no obvious effect on the mechanical properties and corrosion resistance of the alloy. To the welding performance of the alloy, the Zn content is controlled below 0.2%.