2A11 aluminum plate is the earliest type of hard aluminum used, commonly known as standard hard aluminum, with medium strength. It has good plasticity in annealing, hard quenching, and hot states, and can be strengthened by heat treatment. It is used in quenching and natural aging states, with good spot welding weldability. When using 2A11 as a welding material for gas welding and argon arc welding, there is a tendency for cracks; Aluminum coated sheets have good stability, while those without aluminum coating have low corrosion resistance and tend to develop intergranular corrosion when heated above 100 ℃.