Magnesium AZ31B-H24，UNS M11311,E FOUR

Magnesium AZ31B-H24 (UNS M11311) Wrought Alloy Product Introduction** **Product Description:** Magnesium AZ31B-H24 is one of the most common and commercially significant tempers of the AZ31B wrought magnesium alloy. Designated under the Unified Numbering System as **UNS M11311**, the **-H24** temper indicates that the material has been strain-hardened (rolled or worked) and then partially annealed. This specific thermo-mechanical processing results in a product that offers an excellent balance of strength and ductility, along with good dimensional stability. It is the standard temper for AZ31B sheet and plate, providing a combination of properties ideal for a wide range of lightweight structural applications. --- #### **1. Chemical Composition (Weight %)** The chemical composition is consistent with the AZ31B specification, known for its controlled impurity limits for enhanced corrosion resistance. | Element | Minimum (%) | Maximum (%) | Key Function | | :--- | :--- | :--- | :--- | | **Aluminum (Al)** | 2.5 | 3.5 | Primary solid solution strengthener. | | **Zinc (Zn)** | 0.6 | 1.4 | Enhances strength and corrosion resistance. | | **Manganese (Mn)** | 0.2 | 1.0 | Improves corrosion resistance by forming stable compounds with iron. | | **Silicon (Si)** | - | 0.10 | Impurity control. | | **Copper (Cu)** | - | 0.05 | Impurity control (minimized for corrosion resistance). | | **Iron (Fe)** | - | 0.005 | Impurity control (strictly limited). | | **Nickel (Ni)** | - | 0.005 | Impurity control (strictly limited). | | **Other Elements** | - | 0.30 (total) | - | | **Magnesium (Mg)** | **Balance** | | | *Note: The strict control of Fe, Cu, and Ni impurities is critical for maintaining the alloy's superior corrosion performance compared to non-"B" grades.* --- #### **2. Physical Properties** The physical properties are inherent to the alloy and are not significantly altered by the H24 temper. | Property | Value / Description | Condition | | :--- | :--- | :--- | | **Density** | 1.77 g/cm³ (0.064 lb/in³) | At 20°C | | **Melting Point** | ~ 605 - 630 °C (1121 - 1166 °F) | - | | **Thermal Conductivity** | 76 - 96 W/m·K | At 25°C | | **Coefficient of Thermal Expansion** | 26.0 μm/m·°C | 20 - 100°C | | **Electrical Resistivity** | ~ 92 nΩ·m | At 20°C | | **Modulus of Elasticity** | 45 GPa (6.5 x 10⁶ psi) | - | | **Shear Modulus** | 17 GPa (2.4 x 10⁶ psi) | - | | **Poisson's Ratio** | 0.35 | - | --- #### **3. Mechanical Properties (Typical for H24 Temper - Sheet)** The H24 temper is defined by its specific mechanical profile, which is stronger than the O temper but still retains useful formability. | Property | Typical Value (ASTM B90) | | :--- | :--- | | **Tensile Strength** | 255 - 275 MPa (37 - 40 ksi) | | **Yield Strength (0.2% Offset)** | 150 - 180 MPa (22 - 26 ksi) | | **Elongation** | 8 - 15% | | **Compressive Yield Strength** | 110 - 130 MPa (16 - 19 ksi) | | **Hardness** | 55 - 65 HB | *Note: This balance of properties makes AZ31B-H24 the go-to temper for sheet metal components requiring light forming.* --- #### **4. International Standards** AZ31B-H24 is the primary temper specified for sheet and plate in many international standards. | Standard Organization | Standard Designation for AZ31B-H24 | | :--- | :--- | | **ASTM International** | **ASTM B90** (Sheet and Plate - H24 is a standard temper) | | **SAE International** | **SAE J465** | | **UNS (Unified Numbering System)** | **M11311** | | **ISO (International Org. for Standardization)** | **ISO 3116** (Wrought Magnesium and Magnesium Alloys) | | **AMS (Aerospace Material Spec.)** | **AMS 4375** (Sheet and Plate, typically supplied in H24 condition) | --- #### **5. Product Applications** The excellent balance of strength, formability, and lightweight makes AZ31B-H24 applicable across numerous industries. * **Aerospace:** * Aircraft skin and fuselage panels * Interior partitions, flooring, and seating components * Avionics covers and housings * Wing and fairing components * **Automotive:** * Interior body panels (e.g., inner door skins, trunk lids) * Seat frames and structures * Body-in-white components for weight reduction * **Electronics:** * Laptop and tablet casing components * Frames for flat-panel displays * Housings for cameras and portable projectors * **General Industry:** * Panels for portable machinery * Lightweight jigs and fixtures * Cover plates and protective housings --- #### **6. Key Characteristics & Considerations** * **Advantages of the H24 Temper:** * **Optimal Property Balance:** Offers the best all-around combination of strength and ductility for sheet stock. * **Good Room-Temperature Formability:** Can undergo moderate bending and shaping operations without cracking. * **Dimensional Stability:** The partial anneal relieves most of the internal stresses from rolling, reducing the risk of distortion. * **Excellent Specific Strength:** Very high strength-to-weight ratio. * **Good Machinability:** Can be machined to high tolerances with an excellent surface finish. * **Considerations:** * **Limited Severe Formability:** Not as formable as the O-temper; severe deep drawing or stretching may require annealing. * **Corrosion:** Requires protective coatings (e.g., anodizing, painting) for use in corrosive environments, especially where salt is present. * **Low High-Temperature Strength:** Mechanical properties degrade significantly above ~120°C (250°F); not suitable for elevated temperature service. **Summary:** **Magnesium AZ31B-H24 (UNS M11311)** is the industry-standard temper for AZ31B sheet and plate, prized for its **optimal balance of strength, ductility, and stability**. It is the default choice for a vast range of applications in aerospace, automotive, and electronics where lightweight structural performance is critical and the material must be capable of undergoing moderate forming operations during manufacturing.

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 3294 gallon liquid totes Special package is available on request.