3A21 aluminum plate is an Al-Mn series alloy. 3A21 aluminum plate is the most widely used anti-rust aluminum. Its strength is not high (only slightly higher than industrial pure aluminum) and cannot be strengthened by heat treatment, so cold working methods are often used to improve its mechanical properties. ; High plasticity in the annealed state, good plasticity during semi-cold work hardening, low plasticity during cold work hardening, good corrosion resistance, good weldability, and poor machinability.

3A21 aluminum plate is mainly used for low-load parts that require high plasticity and good weldability, working in liquid or gaseous media, such as fuel tanks, gasoline or lubricating oil pipes, various liquid containers and other small loads made by deep drawing Parts: Wire rods are used to make rivets. 3003 aluminum plate has good formability, weldability and corrosion resistance. Used for processing parts that require good formability, high corrosion resistance and good weldability, or work that requires both these properties and higher strength than the 1 series alloy, such as kitchenware, food and chemical products handling and storage Installations, tanks and tanks for transporting liquid products, various pressure vessels and pipes made of thin plates, general utensils, heat sinks, makeup boards, photocopier drums, and ship materials.
3A21 Aluminum plate heat treatment specification:
1) Homogenization annealing: heating at 510～520℃; heat preservation for 4～6h; air cooling. 2) Rapid annealing: heating 350～410℃; depending on the effective thickness of the material, the holding time is 30～120min; air or water cooling. 3) High temperature annealing: heating at 350～500℃; when the thickness of the finished product is ≥6mm, the holding time is 10～30min, when it is less than 6mm, it will be heated until it passes through; air cooling. 4) Low temperature annealing: heating 250～300℃; holding time 1～3h; air or water cooling.