Alloy 77,Nilomag 77,，EFORU

### **Alloy 77 / Nilomag® 77 - Technical Datasheet** --- #### **1. Overview** **Alloy 77**, commercially known as **Nilomag® 77**, is a specialized nickel-iron controlled expansion alloy engineered for applications requiring extremely low thermal expansion characteristics combined with high dimensional stability. This alloy belongs to the super-Invar family, offering superior thermal expansion control compared to standard Invar 36, particularly in the critical temperature range from -50°C to +100°C. --- #### **2. Chemical Composition (Weight %)** The composition is optimized for minimum thermal expansion. | Element | Content (%) | Role & Benefit | |---------|-------------|----------------| | **Nickel (Ni)** | 35.0 - 37.0 | Primary expansion control element | | **Iron (Fe)** | Balance | Base element | | **Cobalt (Co)** | 4.5 - 5.5 | Enhances low expansion characteristics | | **Manganese (Mn)** | 0.20 - 0.50 | Deoxidation and workability | | **Silicon (Si)** | 0.15 - 0.25 | Deoxidizer and fluidity agent | | **Carbon (C)** | ≤ 0.03 | Minimizes carbide formation | | **Sulfur (S)** | ≤ 0.015 | Controlled impurity | | **Phosphorus (P)** | ≤ 0.015 | Controlled impurity | *Note: "Nilomag" is a registered trademark of Vacuumschmelze GmbH & Co. KG* --- #### **3. Physical Properties** Exceptional thermal stability defines this alloy's characteristics. | Property | Value | |----------|-------| | **Density** | 8.10 g/cm³ (0.293 lb/in³) | | **Melting Point** | 1430°C (2605°F) | | **Specific Heat (20°C)** | 515 J/kg·K | | **Thermal Conductivity** | 10.5 W/m·K (20°C) | | **Mean Coefficient of Thermal Expansion** | **≤ 0.6 × 10⁻⁶/°C (20-100°C)**
**1.2 × 10⁻⁶/°C (20-200°C)** | | **Curie Temperature** | ~180°C (355°F) | | **Electrical Resistivity** | 0.80 μΩ·m | | **Modulus of Elasticity** | 145 GPa (21 × 10⁶ psi) | | **Magnetic Properties** | Ferromagnetic | --- #### **4. Mechanical Properties (Annealed Condition)** The alloy provides adequate strength for precision applications. | Property | Value | |----------|-------| | **Tensile Strength** | 480 MPa (70 ksi) | | **Yield Strength (0.2% Offset)** | 280 MPa (41 ksi) | | **Elongation** | 30% | | **Hardness** | 70 HRB | | **Fatigue Strength** | 240 MPa (35 ksi) | --- #### **5. Product Applications** **Alloy 77** serves in ultra-precision applications where minimal thermal expansion is critical: - **Aerospace & Defense:** - Satellite structural components - Space telescope frameworks - Inertial guidance system housings - Radar antenna structures - **Scientific Instruments:** - Interferometer bases - Precision laser frames - Metrology equipment standards - Electron microscope components - **Semiconductor Manufacturing:** - Lithography stage components - Wafer handling systems - Mask alignment fixtures - **Precision Engineering:** - Length standards - Coordinate measuring machine frames - Optical mounting systems - **Cryogenic Applications:** - LNG measurement equipment - Superconducting magnet supports - Cryogenic storage dimensional controls --- #### **6. International Standards** The material meets various international specifications: | Standard | Specification | |----------|---------------| | **ASTM** | ASTM F1684 - Grade 77 | | **UNS** | UNS K94700 | | **DIN** | DIN 17745 - Ni36Co5 | | **EN** | EN 10111 - FeNi36Co5 | | **JIS** | JIS G2311 - NSC77 | --- #### **7. Fabrication & Processing** - **Machining:** Requires sharp tools and positive rake angles - **Forming:** Good formability in annealed condition - **Welding:** Suitable for TIG and electron beam welding - **Heat Treatment:** Stress relief at 425-540°C (800-1000°F) - **Surface Treatment:** Can be electroplated with proper preparation --- #### **8. Special Characteristics** - **Aging Stability:** Excellent long-term dimensional stability - **Thermal Cycling:** Maintains properties through repeated cycles - **Cryogenic Performance:** Stable at cryogenic temperatures - **Magnetic Response:** Predictable magnetic properties --- #### **9. Summary** **Alloy 77 (Nilomag® 77)** represents the pinnacle of low thermal expansion metal alloys, offering nearly zero expansion characteristics in the critical room temperature range. Its exceptional dimensional stability makes it indispensable for the most demanding precision applications in aerospace, scientific instrumentation, and semiconductor manufacturing. The alloy's predictable behavior across temperature variations, combined with good manufacturability, establishes it as the material of choice for applications where thermal dimensional changes must be minimized to the greatest extent possible. Governed by international standards including ASTM F1684, it continues to enable technological advances in fields requiring ultimate precision and 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 1711 gallon liquid totes Special package is available on request.