7075 aluminum products (7075 aluminum alloy) are mainly classified by product form into: 7075 aluminum plates, bars, tubes, wires, strips (coils), and 7075 aluminum forgings; 7075 aluminum commonly comes in heat treatment states such as T6, T651, T73, T7351, and T76.
Classification of 7075 aluminum products:
1. By forming process and shape: 7075 aluminum products include aluminum plates/strips/coils (cold-rolled or hot-rolled), 7075 aluminum bars/profiles (extruded or forged), 7075 aluminum tubes/hollow profiles, aluminum wires/coils (drawn), and free forgings/die forgings (such as aerospace structural parts, gears, and shafts).
2. By heat treatment state: Commonly available are T6 (solution treatment + artificial aging, highest strength), T651 (T6 + pre-stretching, low internal stress, dimensional stability), T73/T7351 (over-aging, improves stress corrosion resistance but slightly reduces strength), T76 (double-stage aging, balances strength and corrosion resistance), and annealed (O) or forged (F) states for subsequent processing.
3. By special surface/function: Such as mirror aluminum plates (high reflectivity surface), clad aluminum 7075 (surface coated with a pure aluminum layer to improve corrosion resistance), ultra-low temperature or pre-aged states (for special working conditions).
7075 is an Al-Zn-Mg-Cu series of ultra-hard, heat-treatable wrought aluminum alloy. It is not primarily produced in “cast” or “powder” form; industrially, it is mainly produced as wrought metal (rolled, extruded, drawn, forged), conforming to the unified designations of Chinese national standards (GB/T 3880, GB/T 3190) and American standards (AA 7075). Different forms are often matched with specific tempers (e.g., plates are often supplied in T651, while bars can be supplied in T6 or T7351). Selection must consider strength, corrosion resistance, machinability, and subsequent heat treatment requirements.
Characteristics of 7075 aluminum products:
7075 aluminum alloy (Al-Zn-Mg-Cu series) is one of the highest-strength commercially available heat-treatable wrought aluminum alloys, characterized by ultra-high strength, good machinability, and moderate corrosion resistance, but poor weldability and susceptibility to stress corrosion.
1. Ultra-high strength: T6 tensile strength ≥524–572 MPa, yield strength ≥455–495 MPa, hardness approximately 150 HB, specific strength (strength/density) far exceeding most steels, density approximately 2.81–2.85 g/cm³.
2. Heat-treatable: Primarily strengthened by solution treatment and aging (e.g., T6, T651) to precipitate MgZn₂ strengthening phases; over-aged states (e.g., T73, T7351) can significantly improve stress corrosion resistance, but strength decreases by approximately 10%.
3. Excellent machinability and wear resistance: Fine-grained structure facilitates CNC cutting, drilling, and thread rolling, with low tool wear; however, it has lower plasticity (elongation approximately 6–11%), and strength decreases significantly at high temperatures (>120℃).
4. Moderate corrosion resistance: Sensitive to stress corrosion cracking (SCC) and exfoliation corrosion (especially in the T6 state), requiring cladding, anodizing, or the use of over-aged states such as T73 for improvement; anodizing is possible.
5. Poor weldability: Fusion welding is prone to hot cracking and porosity; joint strength is only 60–70% of the base material. Aerospace/structural components often use riveting or bolting; recent improvements have been made through laser welding and micro-alloying.
6. Excellent low-temperature performance: Exhibits a “double-enhancement effect” (simultaneous improvement in elongation and hardening capacity) at ultra-low temperatures of -196℃, suitable for aerospace cryogenic components.
7. Typical composition: Zn 5.1–6.1%, Mg 2.1–2.9%, Cu 1.2–2.0%, Cr 0.18–0.28%, balance Al (Si≤0.4%, Fe≤0.5%).
8. Main limitations: Cannot be used directly in corrosive/humid environments (without protection); welding requires special processes; high risk of SCC in T6 state.
Applications of 7075 aluminum products:
7075 aluminum (7075 aluminum alloy) is an Al-Zn-Mg-Cu series ultra-hard heat-treatable aluminum alloy, known for its high strength (tensile strength ≥560 MPa in T6 state). It is mainly used in aerospace, high-end sports equipment, mold manufacturing, and new energy vehicles—fields with stringent strength-to-weight ratio requirements.
1. Aerospace: Aircraft skin, wing spars, stringers, landing gear, missile components, high-strength nuts, and other load-bearing structural components (commonly used in T7351 or T651 state to balance strength and stress corrosion resistance).
2. Molds and tooling: Blow molds, ultrasonic welding molds, injection molds, semiconductor packaging fixtures, CNC machining jigs (due to wear resistance and ease of precision machining).
3. High-end sports and consumer electronics: Bicycle frames, golf club heads, carabiners, racing car parts; previously used in smartphone body materials (e.g., OPPO N3).
4. Transportation: Battery pack structural components for new energy vehicles, suspension system connectors, key components for high-speed trains (lightweight alternatives to steel).
5. Defense and machinery: Firearm parts, armored vehicle components, gears, shafts, high-stress components for hydraulic systems (note their poor weldability; riveting/adhesive bonding is commonly used).
