Hardness is first and foremost related to the chemical composition of the alloy. Second, different states also have a greater impact. From the point of view of the highest hardness that can be achieved, the 7 series, 2 series, 4 series, 5 series, 3 series, and 1 series are successively lowered.
Strength is an important factor that must be considered when designing a product. Especially when an aluminum alloy component is used as a component, the appropriate alloy should be selected according to the pressure it is subjected to. Pure aluminum has the lowest strength, while the 2 and 7 series heat treated alloys have the highest strength. Hardness and strength have a certain positive relationship.
3. Corrosion resistance
Corrosion resistance includes chemical corrosion resistance, electrochemical corrosion resistance, and stress corrosion resistance. In general, the corrosion resistance of the 1st pure aluminum is the best, and the 5 series is good, followed by the non-straight line and the 6th line, the 2nd line and the 7th line. The principle of corrosion resistance selection should be based on the application. When high-strength alloys are used in corrosive environments, various anti-corrosion composites must be used.
4. Processing performance
Processing properties include formability and cutting performance. Since the formability is related to the state, after selecting the aluminum alloy grade, it is necessary to consider the strength range of various states, and usually the material having high strength is not easily formed. If the aluminum material is subjected to forming, such as bending, drawing, deep drawing, etc., the formability of the material in the fully annealed state is optimal, and conversely, the formability of the material in the heat-treated state is the worst. The cutting performance of aluminum alloy has a great relationship with the alloy composition. Generally, the aluminum alloy with higher strength has better machinability, and the lower strength has poor machinability. Machinability of aluminum alloys is an important consideration for molds, joints, and other products that require machining.
5. Welding performance
Most aluminum alloys are welded without problems, especially some 5-Series aluminum alloys, which are designed for welding considerations. Relatively speaking, some 2 series and 7 series aluminum alloys are more difficult to weld.