7229 Aluminum alloy,Aluminum 7229 alloy，E FORU

### **7229 Aluminum Alloy: High-Strength Automotive Alloy** **7229 Aluminum Alloy** is a heat-treatable aluminum-zinc-magnesium alloy specifically engineered for automotive body sheet applications requiring high strength after paint baking, excellent formability, and superior surface quality. This alloy is particularly designed for exposed automotive body panels where both structural performance and aesthetic appearance are critical requirements. --- #### **1. Chemical Composition** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 4.0 - 5.0 | Primary strengthening element through formation of MgZn₂ precipitates | | **Magnesium (Mg)** | 1.2 - 2.0 | Enhances strength and paint bake response | | **Copper (Cu)** | 0.40 - 0.9 | Improves strength and stress corrosion resistance | | **Iron (Fe)** | ≤ 0.15 | Tightly controlled impurity for surface quality | | **Silicon (Si)** | ≤ 0.12 | Tightly controlled impurity for formability | | **Manganese (Mn)** | 0.05 - 0.20 | Grain structure control | | **Chromium (Cr)** | 0.08 - 0.20 | Enhances corrosion resistance | | **Zirconium (Zr)** | 0.08 - 0.15 | Grain refiner and recrystallization inhibitor | | **Titanium (Ti)** | ≤ 0.08 | Grain refiner | | **Other Elements** | ≤ 0.05 each; ≤ 0.15 total | - | | **Aluminum (Al)** | Balance | Base metal | --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.79 g/cm³ (0.101 lb/in³) | | **Melting Range** | 555°C - 645°C (1031°F - 1193°F) | | **Electrical Conductivity** | 40-44% IACS | | **Thermal Conductivity** | 150-170 W/m·K | | **Coefficient of Thermal Expansion** | 23.6 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 69 GPa (10.0 × 10⁶ psi) | --- #### **3. Mechanical Properties (Typical for T4 and After Paint Bake)** | Property | T4 Temper | After Paint Bake (180°C/30min) | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 240 - 290 MPa (35 - 42 ksi) | 340 - 390 MPa (49 - 57 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 120 - 160 MPa (17 - 23 ksi) | 300 - 350 MPa (44 - 51 ksi) | | **Elongation** | 20-26% | 12-16% | | **Brinell Hardness** | 60 - 75 HB | 95 - 115 HB | --- #### **4. Product Applications** **7229 Aluminum Alloy** is extensively used in automotive applications: * **Automotive Body Panels:** * Hoods and trunk lids * Doors and fenders * Roof panels * Body side panels * Tailgates * **Structural Components:** * Reinforcements * Brackets and supports * Structural inner panels * **Transportation Applications:** * Truck body panels * Bus exterior components * Railway vehicle bodywork * **Consumer and Industrial:** * Appliance panels * Architectural panels * High-quality painted components --- #### **5. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7229 | AA Teal Sheets | | **ASTM International** | 7229 | ASTM B209 | | **European Norm** | EN AW-7229 | EN 485-2 | | **Japanese Standards** | A7229 | JIS H 4000 | | **Unified Numbering System** | A97229 | UNS Registry | --- #### **6. Key Characteristics** **Advantages:** * **Excellent surface quality** for painting * **High strength** after paint bake cycle * **Superior formability** in T4 temper * **Good corrosion resistance** * **Excellent hemming characteristics** * **Good weldability** * **Consistent mechanical properties** **Limitations:** * Requires precise heat treatment control * Limited to sheet product forms * Higher cost than some automotive alloys * Not suitable for high-temperature applications --- #### **7. Manufacturing Considerations** * **Stamping:** Excellent formability in T4 temper for complex shapes * **Welding:** Good spot weldability and MIG welding compatibility * **Hemming:** Superior edge hemming characteristics * **Painting:** Excellent surface for paint adhesion and finish * **Heat Treatment:** Excellent paint bake response --- #### **8. Special Features** **7229 Aluminum Alloy** offers automotive-specific advantages: * **Paint Bake Hardening:** Significant strength increase during paint curing cycle (typically 180°C for 20-30 minutes) * **Surface Quality:** Excellent for Class A automotive surfaces * **Weight Reduction:** 40-50% lighter than equivalent steel components * **Recyclability:** Fully recyclable with high scrap value **Automotive Manufacturing Process:** 1. Stamping in T4 temper (typical yield strength: 120-160 MPa) 2. Forming to final shape 3. Assembly and welding 4. Phosphating and electrocoating 5. Paint bake cycle (180°C for 20-30 minutes) 6. Final strength development (typical yield strength: 300-350 MPa) --- #### **9. Performance Characteristics** * **Corrosion Resistance:** Excellent with proper surface treatment * **Fatigue Performance:** Good for automotive body applications * **Dent Resistance:** Superior to lower strength aluminum alloys * **Crash Performance:** Good energy absorption characteristics **7229 Aluminum Alloy** represents specialized development in automotive aluminum technology, specifically engineered to meet the demanding requirements of modern vehicle manufacturing. The alloy's unique combination of high strength after paint baking, excellent formability in the soft temper, and superior surface quality makes it particularly valuable for automotive manufacturers seeking to reduce vehicle weight while maintaining structural integrity and aesthetic appeal. The alloy's compatibility with existing automotive manufacturing processes and its excellent paint bake response have made it a preferred choice for lightweight automotive body applications in the global automotive industry.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2203 gallon liquid totes Special package is available on request.