Invar 36,Super Invar 32-5,UNS K93603,E FORU

### **Super Invar 32-5 / UNS K93603** **Ultra-Low Expansion Iron-Nickel-Cobalt Alloy for Extreme Thermal Stability** --- #### **1. Overview** **Super Invar 32-5**, classified under **UNS K93603**, represents an advanced evolution of traditional Invar alloys, offering even lower thermal expansion characteristics through precise control of nickel content and strategic cobalt additions. This iron-nickel-cobalt alloy exhibits nearly zero thermal expansion at room temperature, making it the material of choice for the most demanding applications where dimensional stability against temperature variations is absolutely critical. Super Invar achieves its exceptional properties through a carefully balanced composition that optimizes the Invar effect across a specific temperature range. --- #### **2. Chemical Composition (Weight %)** The typical chemical composition of Super Invar 32-5 is outlined below. The balance is Iron (Fe). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Forms the primary matrix of the alloy system. | | **Nickel (Ni)** | 31.5 - 32.5 | Primary element controlling the thermal expansion minimum point and range. | | **Cobalt (Co)** | 4.5 - 5.5 | Shifts and optimizes the temperature range for minimum thermal expansion. | | **Manganese (Mn)** | 0.20 - 0.50 | Enhances workability and acts as a deoxidizer during processing. | | **Silicon (Si)** | 0.10 - 0.25 | Controlled addition to improve manufacturing characteristics. | | **Carbon (C)** | 0.02 max | Minimized to prevent aging effects and maintain long-term stability. | | **Chromium (Cr)** | 0.10 max | Controlled impurity. | | **Copper (Cu)** | 0.10 max | Controlled impurity. | | **Aluminum (Al)** | 0.10 max | Controlled impurity. | | **Molybdenum (Mo)** | 0.05 max | Controlled impurity. | | **Sulfur (S)** | 0.008 max | Kept at ultra-low levels to ensure purity and stability. | | **Phosphorus (P)** | 0.008 max | Minimized to prevent embrittlement and aging effects. | --- #### **3. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.13 g/cm³ (0.294 lb/in³) | | **Melting Range** | ~ 1420 - 1430 °C (2588 - 2606 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 100°C (68 - 212°F): **0.3 x 10⁻⁶/°C** (0.17 x 10⁻⁶/°F)
20 - 200°C (68 - 392°F): **0.8 x 10⁻⁶/°C** (0.44 x 10⁻⁶/°F)
20 - 300°C (68 - 572°F): **1.8 x 10⁻⁶/°C** (1.0 x 10⁻⁶/°F) | | **Thermal Conductivity** | 11.0 W/m·K (76 Btu·in/hr·ft²·°F) at 20°C (68°F) | | **Specific Heat Capacity** | 510 J/kg·K (0.122 Btu/lb·°F) at 20°C (68°F) | | **Electrical Resistivity** | 0.78 μΩ·m at 20°C (68°F) | | **Modulus of Elasticity (Young's Modulus)** | 144 GPa (20.9 x 10⁶ psi) at 20°C (68°F) | | **Curie Temperature** | ~ 265 °C (509 °F) | | **Magnetic Properties** | Ferromagnetic below Curie temperature | --- #### **4. Mechanical Properties (Typical for Annealed Condition)** | Property | Value at Room Temperature | | :--- | :--- | | **Tensile Strength** | 470 MPa (68 ksi) | | **Yield Strength (0.2% Offset)** | 300 MPa (44 ksi) | | **Elongation (in 50 mm / 2 in)** | 34% | | **Reduction of Area** | 70% | | **Hardness (Rockwell B)** | 74 HRB | | **Vickers Hardness** | 150 HV | --- #### **5. International Standards** Super Invar 32-5 complies with the following international specifications: * **ASTM:** * **F1684:** Standard Specification for Iron-Nickel and Iron-Nickel-Cobalt Alloys for Low Thermal Expansion Applications * **AMS:** * **AMS 7726:** Super Invar Alloy Sheet, Strip, and Plate * **UNS:** K93603 * **ISO:** * **ISO 19960:** Iron-nickel low expansion alloys * **JIS:** * **JIS G 2311:** Iron-nickel thermal expansion alloys * **Aerospace Standards:** * Various manufacturer specifications for precision components --- #### **6. Product Applications** Super Invar 32-5 is utilized in the most demanding thermal stability applications: * **Ultra-Precision Aerospace Systems:** * Space telescope structural components * Satellite metrology frames * Interferometric baseline structures * High-resolution imaging systems * **Scientific Research Instruments:** * Gravity wave detector components * Atomic clock reference structures * Ultra-stable laser systems * Fundamental physics experiment apparatus * **Semiconductor Manufacturing:** * Extreme ultraviolet (EUV) lithography stages * Wafer stepper reference frames * Mask alignment systems * Critical dimension measurement equipment * **Metrology and Calibration:** * Primary length standards * Ultra-precision gauge blocks * Calibration reference artifacts * Standards laboratory equipment * **Advanced Optical Systems:** * Large telescope mirror supports * Optical delay lines * Interferometer arms * Laser gyroscope frames --- #### **7. Key Characteristics & Advantages** * **Ultra-Low Thermal Expansion:** Exceptional CTE as low as 0.3 x 10⁻⁶/°C at room temperature * **Near-Zero Expansion Behavior:** Approaches theoretical minimum thermal expansion in the 20-100°C range * **Superior Thermal Stability:** Outperforms standard Invar 36 in critical temperature ranges * **Excellent Mechanical Properties:** Maintains good strength and ductility despite ultra-low expansion * **Optimized Composition:** Cobalt addition fine-tunes the thermal expansion minimum point * **High Purity Requirements:** Strict control of trace elements ensures consistent performance * **Long-Term Dimensional Stability:** Minimal aging effects for permanent precision applications * **Proven in Extreme Applications:** Trusted for the most demanding scientific and aerospace missions --- **Disclaimer:** *The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes. Super Invar requires specialized heat treatment and handling to achieve its optimal ultra-low expansion properties and may be subject to specific aging treatments for maximum stability.*

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 1683 gallon liquid totes Special package is available on request.