Invar 36,Alloy 36 Tube,UNS K93600,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

### **Product Datasheet: Invar 36 / Alloy 36 / UNS K93600 Low Expansion Alloy** #### **1. Overview** Invar 36, also known as Alloy 36 or by its unified numbering system code UNS K93600, is a nickel-iron alloy renowned for its exceptionally low coefficient of thermal expansion (CTE) at room temperature and up to approximately 400°C. The name "Invar" derives from the word "invariable," highlighting its key property of dimensional stability with temperature changes. This unique characteristic makes it an indispensable material in applications where precision and stability are critical. #### **2. Key Characteristics** * **Exceptionally Low Thermal Expansion:** Exhibits a near-zero CTE within specific temperature ranges. * **High Dimensional Stability:** Maintains its shape and size despite temperature fluctuations. * **Good Strength and Ductility:** Offers excellent mechanical properties for fabrication and service. * **Excellent Machinability:** Can be machined using standard methods, though it work-hardens. * **Good Cryogenic Properties:** Maintains toughness and low CTE at very low temperatures. #### **3. Chemical Composition (Weight % Typical)** The properties of Invar 36 are primarily derived from its specific nickel content, which is precisely controlled. | Element | Content (%) | | :--- | :--- | | **Nickel (Ni)** | 36.0% | | **Iron (Fe)** | Balance | | **Carbon (C)** | ≤ 0.05% | | **Manganese (Mn)** | ≤ 0.35% | | **Silicon (Si)** | ≤ 0.25% | | **Phosphorus (P)** | ≤ 0.015% | | **Sulfur (S)** | ≤ 0.015% | | **Cobalt (Co)** | ≤ 0.50% | *Note: Composition may vary slightly depending on the manufacturing standard and form.* #### **4. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.11 g/cm³ (0.293 lb/in³) | | **Melting Point** | ~1427°C (2600°F) | | **Mean Coefficient of Thermal Expansion (CTE)** | 1.6 x 10⁻⁶/°C (0.9 x 10⁻⁶/°F) | | | **Range:** 20°C to 100°C (68°F to 212°F) | | **Thermal Conductivity** | 10.5 W/m·K | | | **At:** 100°C (212°F) | | **Specific Heat** | 515 J/kg·K | | | **At:** 100°C (212°F) | | **Electrical Resistivity** | 0.83 μΩ·m | | **Modulus of Elasticity** | 145 GPa (21 x 10⁶ psi) | | **Curie Temperature** | ~279°C (534°F) | #### **5. Mechanical Properties (Typical for Annealed Condition)** | Property | Value | | :--- | :--- | | **Tensile Strength** | 517 MPa (75 ksi) | | **Yield Strength (0.2% Offset)** | 276 MPa (40 ksi) | | **Elongation (in 2")** | 30% | | **Hardness (Rockwell B)** | 75 HRB | #### **6. International Standards** Invar 36 is covered by a range of international standards, which may specify slightly different requirements for composition, form, and properties. * **ASTM:** ASTM F1684 - Standard Specification for Iron-Nickel and Iron-Nickel-Cobalt Alloys for Low Thermal Expansion Applications * **AMS:** AMS 7725 (Sheet, Strip, and Plate), AMS 7724 (Bar and Forging) * **UNS:** K93600 * **DIN:** 1.3912 / Ni36 * **JIS:** NILO 36 / N36 * **AFNOR:** FeNi36 #### **7. Product Forms & Availability: Invar 36 Tube** Invar 36 is available in various forms, with **Invar 36 Tube** being a critical product for specific applications. These tubes are manufactured to precise dimensional tolerances and are available in seamless and welded forms. * **Applications for Invar 36 Tube:** * **Waveguide Components:** Used in satellite communications and radar systems where dimensional stability is crucial to maintain signal integrity. * **Cryogenic Transfer Lines:** For transporting liquefied gases (e.g., LNG) where thermal contraction must be minimized. * **Precision Instrumentation:** As structural components in telescopes, metrology frames, and laser systems. * **Aerospace Structures:** Used in components for satellites and aircraft where thermal cycling is extreme. #### **8. Typical Applications** Beyond tubing, Invar 36 is used in a wide array of high-precision industries: * **Precision Measurement:** Standards scales, geodetic tapes, pendulum rods. * **Electronics & Semiconductors:** Lead frames, shadow masks for color CRT televisions, fixtures for semiconductor manufacturing. * **Aerospace & Defense:** Composite molding tools, satellite structures, optical mounting systems. * **Energy:** LNG storage tanks and transport vessels (as a liner). * **Scientific Instruments:** Components for telescopes, interferometers, and other lab equipment. #### **9. Fabrication and Handling** * **Machining:** It machines similarly to austenitic stainless steel but has a tendency to work-harden. Sharp tools, slow speeds, and heavy feeds are recommended. * **Welding:** Readily weldable using Gas Tungsten Arc Welding (GTAW/TIG) and Gas Metal Arc Welding (GMAW/MIG) processes. Matching filler metals (e.g., Invar 36 wire) are preferred. * **Heat Treatment:** A stress-relief anneal at 790-925°C (1450-1700°F) followed by rapid cooling is typically used to restore low expansion properties after cold working. --- **Disclaimer:** The information provided herein is for reference purposes only. Material properties can vary based on manufacturing process, heat treatment, and product form. For critical applications, always consult the specific material certification and relevant standard specifications.

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 2395 gallon liquid totes Special package is available on request.