3A21 is an AL-Mn series aluminum alloy. It has high plasticity in the 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 gaseous media, such as fuel tanks, gasoline or lubricating oil conduits, various liquid containers and other small-load parts made by deep drawing
【chemical composition】3A21 aluminum alloy
Silicon Si: 0.60
Iron Fe: 0.70
Copper Cu: 0.20
Manganese Mn: 1.0-1.6
Magnesium Mg: 0.05
Zinc Zn: 0.15
Titanium Ti: 0.10-0.20
Aluminum Al: balance
【mechanical properties】3A21 aluminum alloy
Tensile strength σb (MPa) ) 120-160
Conditional yield strength σ0.2 (MPa) )≥85
Heat treatment process:
1) Homogenization annealing: heating at 510-520°C; holding for 4-6 hours; air cooling.
2) Rapid annealing: heating at 350-410°C; 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°C; when the thickness of the finished product is ≥6mm, the holding time is 10-30min; 4) Low-temperature annealing: heating at 250-300°C; holding time for 1-3 hours; air or water cooling.