Invar 36,Nilo 36 Fittings,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 Fittings (UNS K93601) - Product Introduction** #### **Overview** **Invar 36**, commercially known as **Nilo 36 Fittings** (UNS K93601), represents precision-engineered connection components made from the renowned 36% nickel-iron low expansion alloy. These fittings are specifically designed for piping and tubing systems where exceptional dimensional stability under thermal cycling is critical, ensuring reliable performance in cryogenic, aerospace, and precision instrumentation applications. #### **Key Characteristics** - **Ultra-Low Thermal Expansion:** CTE typically **1.6 × 10⁻⁶/°C** (20-100°C) - **Excellent Pressure Integrity:** Suitable for high-pressure and vacuum applications - **Superior Corrosion Resistance:** Comparable to low-alloy steels - **Good Weldability:** Compatible with standard welding processes - **Precision Machining:** Tight dimensional tolerances for reliable connections --- #### **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 CTE (20-100°C)** | **1.6 × 10⁻⁶/°C** | | **Thermal Conductivity** | 10.5 W/m·K | | **Specific Heat Capacity** | 515 J/kg·K | | **Modulus of Elasticity** | 145 GPa | | **Magnetic Properties** | Ferromagnetic below 230°C | --- #### **3. Mechanical Properties** | Property | Value | |----------|-------| | **Tensile Strength** | 480-550 MPa (70-80 ksi) | | **Yield Strength (0.2% Offset)** | 280-350 MPa (41-51 ksi) | | **Elongation** | 30-40% | | **Hardness** | 75-85 HRB | | **Impact Strength** | 100-120 J (74-88 ft-lb) | --- #### **4. Product Applications** **Aerospace & Defense:** - **Aircraft Fuel Systems:** Cryogenic fuel line connections - **Satellite Propulsion Systems:** Propellant management fittings - **Spacecraft Thermal Control:** Cooling system connections - **Avionics Cooling:** Precision fluid circuit fittings **Semiconductor Industry:** - **High-Purity Gas Systems:** Ultra-clean gas panel fittings - **Chemical Delivery Systems:** Corrosive fluid handling - **Vacuum Chamber Fittings:** High-vacuum compatible connections - **Wafer Processing Equipment:** Process gas line fittings **Energy & Industrial:** - **LNG Systems:** Cryogenic transfer line fittings - **Nuclear Instrumentation:** Sensor connection fittings - **Solar Thermal Systems:** High-temperature connections - **Cryogenic Research:** Laboratory cryostat fittings **Precision Instrumentation:** - **Analytical Instruments:** Chromatography system fittings - **Medical Equipment:** MRI and medical imaging systems - **Laboratory Systems:** Research equipment connections - **Metrology Equipment:** Precision measurement systems --- #### **5. International Standards** | Standard Body | Standard Number | Description | |---------------|-----------------|-------------| | **ASTM** | ASTM F1684 | Material Specification for Fittings | | **ASME** | B16.11 | Forged Fittings, Socket-Welding and Threaded | | **ISO** | ISO 9001 | Quality Management Systems | | **DIN** | DIN 1.3912 | Material Standard | | **MIL-STD** | MIL-STD-129 | Marking for Shipment and Storage | --- #### **6. Available Fitting Types** **Connection Types:** - **Socket Weld Fittings:** 2000# to 6000# pressure ratings - **Threaded Fittings:** NPT and BSPP thread types - **Butt Weld Fittings:** Seamless construction - **Special Fittings:** Custom configurations available **Standard Fitting Styles:** - **Elbows:** 45°, 90°, and 180° configurations - **Tees:** Straight and reducing types - **Couplings:** Full and half couplings - **Unions:** Precision ground faces - **Bushings:** Hex and socket types - **Caps:** Socket weld and threaded **Size Range:** - **Socket Weld:** 1/8" to 2" NPS - **Threaded:** 1/8" to 2" NPS - **Butt Weld:** 1/2" to 4" NPS --- #### **7. Fabrication & Quality Assurance** **Manufacturing Processes:** - **Hot Forging:** For superior grain structure - **Precision Machining:** CNC turning and milling - **Surface Treatment:** Passivation and cleaning - **Quality Testing:** 100% dimensional inspection **Testing & Certification:** - **Pressure Testing:** Hydrostatic and pneumatic tests - **Dimensional Verification:** CMM inspection available - **Material Certification:** 3.1 Mill Certificate - **Traceability:** Full heat code traceability **Quality Standards:** - **Surface Finish:** 32 Ra μin maximum - **Dimensional Tolerances:** Per ASME B16.11 - **Marking:** Permanent heat code identification - **Packaging:** Protected to prevent damage --- #### **8. Installation Guidelines** **Welding Procedures:** - **Process:** GTAW (TIG) recommended - **Filler Metal:** AWS A5.14 ERNiFeCr - **Preheat:** Not required for standard thicknesses - **Post-Weld Heat Treatment:** Optional for stress relief **Threaded Connections:** - **Thread Sealant:** Compatible with standard sealants - **Torque Values:** Follow manufacturer recommendations - **Assembly:** Proper alignment critical **Inspection & Maintenance:** - **Leak Testing:** Required after installation - **Periodic Inspection:** Recommended for critical service - **Cleaning:** Suitable for standard cleaning methods --- #### **Conclusion** Nilo 36 Fittings (UNS K93601) provide an exceptional solution for critical connection applications where thermal stability, reliability, and precision are paramount. Their unique combination of low thermal expansion, excellent mechanical properties, and manufacturing precision makes them ideal for aerospace, semiconductor, and energy applications. The comprehensive quality assurance and testing protocols ensure reliable performance in the most demanding thermal cycling environments. Proper selection, installation, and maintenance following manufacturer guidelines are essential for achieving optimal system performance and longevity.

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 2412 gallon liquid totes Special package is available on request.