Invar 36,Nilo 36 ,UNS K93601,E FORU

British Specs:，American Specs: ASTM F1684 MIL-S-16598 Tooling plate ASTM B388 Sheet & strip ASTM B753 K93050 Free-cut Invar，German Specs:WS 1.3912

### **Invar 36 / Nilo 36 (UNS K93601) - Product Introduction** #### **Overview** Invar 36, commercially known as **Nilo 36**, is a nickel-iron alloy registered under **UNS K93601** that exhibits an exceptionally low coefficient of thermal expansion (CTE) at temperatures ranging from cryogenic to approximately 300°C. The name "Nilo" (Nickel-Iron Low Expansion) is a trademarked designation for this family of controlled expansion alloys. This material maintains remarkable dimensional stability across temperature variations, making it indispensable in applications where thermal growth must be minimized. #### **Key Characteristics** * **Ultra-Low Thermal Expansion:** CTE typically **1.5 - 2.0 × 10⁻⁶/°C** (20-100°C) * **Excellent Dimensional Stability:** Maintains precise dimensions under thermal cycling * **Good Mechanical Properties:** Balanced strength and ductility across temperature ranges * **Predictable Thermal Behavior:** Consistent performance from cryogenic to elevated temperatures * **Ferromagnetic Properties:** Magnetic at room temperature --- #### **1. Chemical Composition** | Element | Content (%) | | :--- | :--- | | **Nickel (Ni)** | 35.0 - 37.0 | | **Iron (Fe)** | Balance | | **Carbon (C)** | 0.10 max | | **Manganese (Mn)** | 0.50 max | | **Silicon (Si)** | 0.30 max | | **Phosphorus (P)** | 0.025 max | | **Sulfur (S)** | 0.025 max | | **Cobalt (Co)** | 0.50 max | | **Chromium (Cr)** | 0.25 max | | **Aluminum (Al)** | 0.10 max | *Note: The precise nickel content (36% nominal) is critical for achieving the low expansion characteristics.* --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 8.13 g/cm³ (0.294 lb/in³) | | **Melting Point** | 1425°C (2600°F) | | **Mean Coefficient of Thermal Expansion** | **1.7 × 10⁻⁶/°C** (20-100°C)
2.5 × 10⁻⁶/°C (20-300°C)
4.5 × 10⁻⁶/°C (20-500°C) | | **Thermal Conductivity** | 11.0 W/m·K (at 20°C) | | **Specific Heat Capacity** | 515 J/kg·K (at 20°C) | | **Electrical Resistivity** | 0.75 μΩ·m | | **Curie Temperature** | 230°C (446°F) | | **Magnetic Saturation** | 1.5 Tesla | --- #### **3. Mechanical Properties (Annealed Condition)** | Property | Value | | :--- | :--- | | **Tensile Strength** | 480-550 MPa (70-80 ksi) | | **Yield Strength (0.2% Offset)** | 280-350 MPa (41-51 ksi) | | **Elongation (in 2")** | 30-35% | | **Reduction of Area** | 55-65% | | **Hardness** | 75-85 HRB | | **Modulus of Elasticity** | 145 GPa (21 × 10⁶ psi) | | **Shear Modulus** | 55 GPa (8.0 × 10⁶ psi) | --- #### **4. Product Applications** **Electronics & Semiconductor:** * **Lead Frames:** For high-reliability semiconductor packages * **Optical Display Components:** Shadow masks for high-resolution displays * **RF Packaging:** Housing for microwave and RF components * **Hermetic Seals:** Glass-to-metal seals in electronic packages **Aerospace & Defense:** * **Aerospace Structures:** Components requiring thermal stability * **Satellite Systems:** Optical benches and support structures * **Guidance Systems:** Inertial navigation components * **Radar Systems:** Waveguide components **Precision Instruments:** * **Measurement Standards:** Precision scales and geodetic tapes * **Laser Systems:** Optical mounts and cavity structures * **Scientific Instruments:** Telescope components and laboratory equipment * **Timekeeping Devices:** Precision pendulum rods **Energy & Industrial:** * **Cryogenic Equipment:** LNG transfer lines and storage components * **Power Generation:** Turbine seals and components * **Mold Tools:** For composite manufacturing in aerospace * **Thermal Management:** Components in heating systems --- #### **5. International Standards** | Standard Body | Standard Designation | Product Form | | :--- | :--- | :--- | | **UNS** | **K93601** | All product forms | | **ASTM** | **ASTM F1684** | Sheet, Strip, Plate | | **AMS** | **AMS 7725** | Sheet, Strip, Plate | | **AMS** | **AMS 7724** | Forgings | | **ISO** | **ISO 15156-2** | Petroleum and natural gas industries | | **EN** | **EN 1.3912** | Wrought products | | **DIN** | **DIN 1.3912** | All product forms | | **JIS** | **JIS NCF 2** | Nickel-chromium-iron alloy | --- #### **6. Fabrication Notes** **Machining:** * Use positive rake angles and sharp tools * Recommended speeds: 20-30 SFM for turning * Use sulfurized or chlorinated cutting oils * Account for work hardening during processing **Welding:** * Compatible with GTAW (TIG), GMAW (MIG), and SMAW processes * Use matching filler metal (INVAR 36/UNS K93601) * Preheating not typically required * Post-weld heat treatment recommended for stress relief **Heat Treatment:** * Annealing: 830-880°C (1525-1615°F), rapid cool * Stress Relieving: 425-540°C (800-1000°F) * Avoid prolonged exposure in 425-650°C range --- #### **Conclusion** Nilo 36 (UNS K93601) represents the benchmark for low expansion alloys, offering unparalleled dimensional stability across a wide temperature range. Its consistent performance, coupled with excellent manufacturability, makes it the material of choice for critical applications in aerospace, electronics, and precision instrumentation. The alloy's predictable thermal behavior and reliable mechanical properties ensure long-term performance in the most demanding environments. When specifying Nilo 36, verification against relevant international standards (particularly ASTM F1684 and AMS 7725) is essential to guarantee material performance and traceability.

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 2404 gallon liquid totes Special package is available on request.