1. Basic performance comparison
Alloy composition and strength
7075: It belongs to the Al-Zn-Mg-Cu series of super-hard aluminum, with a zinc content of 5.1-6.1%, a tensile strength of ≥500MPa, and a hardness of 150HRB. The 7075 aluminum polished sheet is suitable for high-strength scenarios (such as aviation aluminum structural parts).
7050: It is also Al-Zn-Mg-Cu, but the zinc content is slightly lower (about 6.2%), with a tensile strength of 450-500MPa. The 7050 aluminum metal sheet focuses on stress corrosion resistance and is suitable for thick plate processing (such as aircraft wing beams).
Corrosion resistance
The original corrosion resistance of 7075 aircraft aluminum sheet is weak, and the protective performance needs to be improved by anodizing or coating (such as PVDF);
7050 flat aluminum sheets have an optimized magnesium/copper ratio, and the stress corrosion cracking resistance is increased by 30%, which is more suitable for salt spray and high humidity environments.
2. Polishing process adaptability
Processing difficulty
The hardness of 7075 aluminum alloy is high (HB 150). When polishing 7075 aluminum alloy plate, multiple precision grinding is required. During the process, 7075 reflective aluminum sheet is prone to orange peel effect. It is recommended to use magnetorheological polishing technology;
The hardness of 7050 is slightly lower (HB 135), and the formability is better. After polishing, the surface roughness of 7075 aluminum blank plate can be controlled at Ra≤0.1μm.
Surface treatment effect
The reflectivity of 7075 aluminum plate can reach more than 85% after polishing, but the adhesion of the oxide film is weak, and hard anodizing (film thickness 20-30μm) is required to enhance wear resistance;
The polishing surface uniformity of 7050 is better, and the density of the oxide film after anodizing is high. The salt spray test life of 7050 anodised aluminum sheet is >1200 hours.
III. Typical application scenarios
7075 aluminum polished plate
Aerospace: T651 state plate is used for aircraft skin and landing gear parts, with outstanding fatigue resistance;
Precision instruments: 7075 high-gloss aluminum plate surface is suitable for medical equipment housing and optical instrument bracket, with a surface hardness of HV 120.
7050 aluminum polished plate
Shipbuilding: T7451 state thick aluminum plate is used for hull structural parts, with excellent seawater corrosion resistance;
Military equipment: High stress corrosion resistance is suitable for extreme environments such as armored vehicles and missile launchers.
