Invar 36,Super Invar 32-5 Tube,UNS K93050,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 Introduction: Invar 36 / Super Invar 32-5 (UNS K93050) Tubing** #### **1. Overview** Invar 36 and Super Invar 32-5 are nickel-iron alloys renowned for their exceptionally low coefficient of thermal expansion (CTE) over a wide temperature range. This unique property makes them indispensable in applications where dimensional stability is critical under varying thermal conditions. * **Invar 36** is the standard low-expansion alloy, offering a near-zero CTE at room temperature. * **Super Invar 32-5** is a modified version with an addition of 5% Cobalt, providing an even lower and more stable CTE than standard Invar 36, particularly in the sub-zero to room temperature range. These alloys are available in tubular form, which combines their superior thermal properties with the advantages of a hollow structure, such as reduced weight and the ability to transport fluids or gases in thermally sensitive systems. The Unified Numbering System (UNS) designation **K93050** covers both Invar 36 and Super Invar. #### **2. Chemical Composition (Weight %)** | Element | Invar 36 (Typical) | Super Invar 32-5 (Typical) | UNS K93050 (General Range) | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | 36.0% | 32.0% | 31.5 - 36.0% | | **Iron (Fe)** | Balance | Balance | Balance | | **Cobalt (Co)** | - | 5.0% | 4.8 - 5.4% (for Super Invar) | | **Carbon (C)** | ≤ 0.05% | ≤ 0.05% | ≤ 0.05% | | **Manganese (Mn)**| ≤ 0.35% | ≤ 0.35% | ≤ 0.35% | | **Silicon (Si)** | ≤ 0.25% | ≤ 0.25% | ≤ 0.25% | | **Chromium (Cr)**| - | - | ≤ 0.20% | | **Sulfur (S)** | ≤ 0.02% | ≤ 0.02% | ≤ 0.02% | | **Phosphorus (P)**| ≤ 0.02% | ≤ 0.02% | ≤ 0.02% | #### **3. Physical & Mechanical Properties** *Note: Properties for tubing are dependent on the manufacturing process (seamless vs. welded), heat treatment, and wall thickness.* | Property | Invar 36 | Super Invar 32-5 | | :--- | :--- | :--- | | **Coefficient of Thermal Expansion (CTE)** | **~1.6 x 10⁻⁶/°C**
(20°C to 100°C) | **~0.6 x 10⁻⁶/°C**
(20°C to 100°C) | | **Density** | 8.11 g/cm³ | 8.13 g/cm³ | | **Melting Point** | ~1427°C (2600°F) | ~1430°C (2610°F) | | **Curie Temperature** | ~279°C (535°F) | ~310°C (590°F) | | **Thermal Conductivity** | 10.5 W/m·K (at 23°C) | 10.5 W/m·K (at 23°C) | | **Specific Heat** | 515 J/kg·K (at 20°C) | 515 J/kg·K (at 20°C) | | **Tensile Strength** | 517 - 621 MPa (75 - 90 ksi) | 517 - 655 MPa (75 - 95 ksi) | | **Yield Strength (0.2% Offset)**| 276 - 414 MPa (40 - 60 ksi) | 276 - 448 MPa (40 - 65 ksi) | | **Elongation (in 2")** | 25 - 35% | 22 - 30% | | **Modulus of Elasticity** | 141 GPa (20.5 x 10⁶ psi) | 141 GPa (20.5 x 10⁶ psi) | #### **4. International Standards** These alloys are covered by various international standards for composition and form. | Standard Type | Invar 36 | Super Invar 32-5 | | :--- | :--- | :--- | | **Material Designation** | ASTM F1684, UNS K93600 | ASTM F1684, UNS K94600 | | **Unified Numbering System (UNS)** | **K93600** | **K94600** | | **European Standard (EN)** | Ni36 (1.3912) | Ni32Co5Cu (1.3981) | | **Japanese Standard (JIS)** | NILO 36 (Cactus 7) | - | *Note: UNS K93050 is a general "catch-all" number for low-expansion iron-nickel alloys. For precise ordering, the specific UNS K93600 (Invar 36) or K94600 (Super Invar) should be used. Tubing may be supplied to dimensional standards like ASTM B724 for welded tubing.* #### **5. Product Applications** Invar 36 and Super Invar tubing are critical in high-precision industries: * **Aerospace & Aviation:** Waveguides, fuel system components, structural members in satellites and spacecraft where temperature fluctuations are extreme. * **Cryogenics:** Transfer lines for liquefied natural gas (LNG), liquid helium, and nitrogen, where thermal contraction must be minimized. * **Precision Instruments:** Frames and structures for laser systems, optical benches, metrology equipment, and telescope mounts. * **Electronics & Semiconductors:** Carrier tubes for wafer processing, shadow masks for thin-film deposition. * **Energy:** Components in solar concentrators and nuclear reactors where dimensional stability is paramount. #### **6. Key Advantages of Tubing Form** * **Ultra-Low Thermal Expansion:** Maintains precise dimensions across a wide temperature range. * **Weight Reduction:** Hollow structure offers significant weight savings compared to solid bars, crucial for aerospace applications. * **Functional Design:** Can be used as a conduit for cooling fluids, gases, or for housing other components in a thermally stable environment. * **High Strength-to-Weight Ratio:** Provides excellent structural integrity while being lightweight. **Disclaimer:** The values provided are typical and for informational purposes. Specific properties for a given tube lot should be confirmed with the manufacturer's certified test report. Machining and welding of these alloys require specialized techniques.

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 2434 gallon liquid totes Special package is available on request.