The Properties and Application of 5xxx Car Aluminum

Car aluminum, especially aluminum alloy outer sheets for automobiles, are the top application of aluminum sheet. The key issues to be solved in its research and development are anti-aging stability, formability, bake hardening, flanging ductility,paint gloss uniformity, dent resistance.

At present, there are two main series of aluminum alloy automotive plates: 6000 series and 5000 series. 6xxx aluminum alloy include 6016, 6014, 6061, 6022, 6111. 5xxx aluminum has 2052, 5083, 5182, 5022, 5023, 5754, etc.

5182 and 5754 aluminum sheet are non-heat-treated work-hardening Al-Mg alloys. They are mainly used in car body structural parts and inner plate. The second phases in the alloy are Fe and Mn. The percentages of the second phase in AA5754 and AA5182 are 0.60% and 0.98%, respectively.

The failure mode of AA5754 and AA5182 during tensile deformation is ductile shear failure. The amount of necking and damage increase with the strain rate. The damage is the result of the growth and coarsening of the holes on the second phase.

Since the initial work hardening performance of aluminum alloy sheet is higher than that of mild steel, its springback during cold bending is also greater than that of mild steel. According to the research the 6022, 6082, 6111 and 6016 t6 aluminum, 5754 aluminum alloy has good formability and corrosion resistance.

6000 aluminum alloys use Si and Mg as alloying elements (6111 alloy also adds Cu as alloying elements). This type of aluminum alloy can be heat-treatable and strengthened. They have has good formability in the pretreatment state, no yield point elongation, suitable for automobile outer sheet.

6016 aluminum also has good bake hardenability. After the paint is baked, it has high flow stress, and the parts have high dent resistance; but after aging, the ductility of the flanging will decrease and the formability will deteriorate.