Invar 36,Nilo 36 Tube,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 Tube (UNS K93601) - Product Introduction** #### **Overview** **Invar 36**, commercially known as **Nilo 36 Tube** (UNS K93601), represents the tubular form of the classic 36% nickel-iron low expansion alloy. Precision tubing made from this material is engineered for applications requiring exceptional dimensional stability, precise internal dimensions, and reliable performance under thermal cycling conditions. The tube form offers superior dimensional control and surface finish compared to standard pipe products, making it ideal for precision instrumentation and fluid handling systems. #### **Key Characteristics** * **Ultra-Low Thermal Expansion:** CTE typically **1.6 × 10⁻⁶/°C** (20-100°C) * **Precision Dimensional Control:** Tight tolerances on OD, ID, and wall thickness * **Excellent Surface Finish:** Smooth internal and external surfaces * **Superior Strength-to-Weight Ratio:** Ideal for weight-sensitive applications * **Excellent Fabricability:** Can be bent, flared, and welded using standard techniques --- #### **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 | --- #### **2. Physical Properties** | Property | Value | |----------|-------| | **Density** | 8.13 g/cm³ (0.294 lb/in³) | | **Melting Point** | 1425°C (2600°F) | | **Mean Coefficient of Thermal Expansion** | **1.6 × 10⁻⁶/°C** (20-100°C)
4.5 × 10⁻⁶/°C (20-500°C) | | **Thermal Conductivity** | 10.5 W/m·K (71 BTU·in/hr·ft²·°F) | | **Specific Heat Capacity** | 515 J/kg·K (0.123 BTU/lb·°F) | | **Modulus of Elasticity** | 145 GPa (21 × 10⁶ psi) | | **Magnetic Properties** | Ferromagnetic below 230°C (446°F) | --- #### **3. Mechanical Properties (Annealed Condition)** | Property | Value | |----------|-------| | **Tensile Strength** | 450-520 MPa (65-75 ksi) | | **Yield Strength (0.2% Offset)** | 250-310 MPa (36-45 ksi) | | **Elongation** | 30-40% | | **Hardness** | 70-80 HRB | | **Shear Modulus** | 55 GPa (8.0 × 10⁶ psi) | --- #### **4. Product Applications** **Aerospace & Defense:** * **Aircraft Hydraulic Lines:** High-stability fluid conveyance systems * **Satellite Propellant Lines:** Precision fuel and oxidizer management * **Thermal Control Systems:** Heat transfer and cooling conduits * **Avionics Cooling:** Precision coolant pathways for electronic systems **Semiconductor Manufacturing:** * **Ultra-High Purity Gas Lines:** For wafer fabrication equipment * **Chemical Delivery Systems:** High-purity chemical distribution * **Vacuum System Components:** Chamber instrumentation and feedthroughs * **Process Tooling:** Internal components for deposition systems **Medical & Scientific:** * **MRI System Components:** Cryogenic and structural elements * **Particle Accelerator Components:** Beam line and vacuum components * **Laboratory Instrumentation:** Precision fluid handling systems * **Telescope Systems:** Cooling and structural applications **Industrial Applications:** * **LNG Instrumentation:** Cryogenic temperature sensing and transfer * **Laser System Components:** Cooling channels and structural elements * **Metrology Equipment:** Precision frames and structural components * **Optical Systems:** Mounting and alignment structures --- #### **5. International Standards** | Standard Body | Standard Number | Description | |---------------|-----------------|-------------| | **ASTM** | ASTM F1684 | Standard Specification for Iron-Nickel and Cobalt-Nickel Alloy Tube | | **AMS** | AMS 7725 | Aerospace Material Specification | | **ASME** | SA-658 | Boiler and Pressure Vessel Code Specification | | **DIN** | DIN 1.3912 | German Standard | | **EN** | EN 1.3912 | European Standard | | **JIS** | JIS NCF 2 | Japanese Industrial Standard | --- #### **6. Available Forms & Specifications** **Tube Types:** * **Seamless Tube:** Highest integrity for pressure applications * **Welded & Drawn Tube:** Superior surface finish and dimensional control * **Hydraulic Tube:** Precision dimensions for fluid power systems * **Instrumentation Tube:** Small diameters for control systems **Standard Sizes:** * **Outside Diameter:** 1.5 mm to 100 mm (0.062" to 4") * **Wall Thickness:** 0.5 mm to 5.0 mm (0.020" to 0.200") * **Lengths:** Standard 3-6 meters, cut-to-length available **Tolerances:** * **OD Tolerance:** ±0.05 mm to ±0.15 mm * **Wall Thickness:** ±10% typical * **Straightness:** 1.5 mm per meter maximum --- #### **7. Fabrication & Processing** **Welding & Joining:** * **Primary Process:** GTAW (TIG) welding * **Filler Metal:** AWS A5.14 ERNiFeCr or matching composition * **Preheat:** Not required for thin-walled tubes * **Post-Weld Heat Treatment:** Recommended at 425-540°C (800-1000°F) **Forming & Bending:** * **Bend Radius:** Minimum 2 × OD for thin-walled tubes * **Bending Methods:** Mandrel bending for tight radii * **Flaring/Flanging:** Standard 37° and 45° flares possible * **Swaging:** Possible with proper tooling **Cutting & Machining:** * **Cutting Methods:** Abrasive cutting, band saw, or tube cutter * **Deburring:** Essential for fluid applications * **Machining:** Similar to other nickel-iron alloys --- #### **8. Quality Assurance** **Testing & Inspection:** * **Dimensional Verification:** 100% dimensional inspection * **Surface Finish:** Ra ≤ 0.8 μm (32 μin) typical * **Pressure Testing:** Hydrostatic or pneumatic testing available * **Non-Destructive Testing:** Eddy current, ultrasonic, or dye penetrant **Certification & Documentation:** * **Material Certification:** 3.1 Mill Certificate * **Traceability:** Heat number and lot traceability maintained * **Compliance Certificates:** RoHS, REACH compliant --- #### **Conclusion** Nilo 36 Tube (UNS K93601) provides an exceptional solution for applications requiring the unique combination of low thermal expansion, precision dimensions, and reliable performance in demanding thermal environments. Its availability in various sizes and configurations, combined with excellent fabrication characteristics, makes it particularly valuable for aerospace, semiconductor, and precision instrumentation applications. The material's consistent performance under thermal cycling conditions ensures long-term reliability in systems where dimensional stability is critical. Proper selection of tube specifications and adherence to recommended fabrication practices are essential for achieving optimal performance in the final application.

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 2408 gallon liquid totes Special package is available on request.