The 3105 aluminum alloy has excellent anti-corrosion properties and good electrical conductivity. The 3105 aluminum sheet has high plasticity in the annealed state, still good plasticity during semi-cold hardening, and low plasticity during cold hardening. It has good corrosion resistance, good weldability, and poor machinability. The 3105 aluminum sheet belongs to the aluminum-manganese alloy and is often used as decorative aluminum plates and building materials aluminum plates. For example, roof aluminum plates, corrugated aluminum plates, and color-coated aluminum plates, etc.