Alloy 48,Nilo 48 Tube,UNS K94800,E FORU

British Specs:，American Specs: ASTM F30，German Specs:

### **Alloy 48 (Nilo 48) - Tube Product Overview** **Alloy 48**, commercially known as **Nilo 48**, is a controlled expansion iron-nickel alloy specifically designed for matched sealing with hard glasses such as borosilicate and alumina-silicate types. The **Tube** form provides precise tubular components for applications requiring exact dimensional control and reliable thermal expansion compatibility with hard glass in critical sealing applications. * **UNS Designation:** **K94800** * **Common Names:** Nilo 48 Tube, Glass Sealing 48 Tubing --- #### **1. Chemical Composition** Precisely controlled chemistry ensures consistent thermal expansion properties in tubular form. | Element | Percentage (%) | Role in the Alloy | |:---|:---|:---| | **Nickel (Ni)** | 47.5 - 48.5 | Primary element controlling CTE characteristics | | **Iron (Fe)** | Balance | Base structural element | | **Manganese (Mn)** | 0.10 - 0.30 | Enhances tube drawing characteristics | | **Silicon (Si)** | 0.10 - 0.30 | Improves glass wetting performance | | **Carbon (C)** | 0.05 max | Limited for optimal ductility in tube forming | | **Sulfur (S)** | 0.02 max | Controlled impurity | | **Phosphorus (P)** | 0.02 max | Controlled impurity | --- #### **2. Physical Properties** Specialized properties optimized for tubular applications and hard glass sealing. | Property | Value / Condition | Notes | |:---|:---|:---| | **Density** | 8.22 g/cm³ (0.297 lb/in³) | | | **Melting Point** | ~1430 °C (2605 °F) | | | **Thermal Expansion Coefficient** | 20-300°C: 8.5-9.2 μm/m·°C
20-400°C: 9.0-9.7 μm/m·°C | Matches borosilicate glass (e.g., Pyrex, Schott 8250) | | **Curie Temperature** | ~480 °C (895 °F) | Critical for CTE matching with hard glasses | | **Thermal Conductivity** | 15.2 W/m·K at 20°C | | | **Electrical Resistivity** | 0.48 μΩ·m at 20°C | | | **Specific Heat** | 0.46 J/g·°C at 20°C | | --- #### **3. Mechanical Properties (Annealed Condition)** **Tube Mechanical Characteristics:** * **Tensile Strength:** 510-580 MPa (74-84 ksi) * **Yield Strength (0.2% Offset):** 270-340 MPa (39-49 ksi) * **Elongation:** 25-35% in 2 inches * **Hardness:** 65-80 HRB * **Modulus of Elasticity:** 154 GPa (22.3 × 10⁶ psi) * **Collapse Pressure:** Varies with diameter-to-wall thickness ratio --- #### **4. Product Specifications & Applications** **Tube Specifications:** * **Diameter Range:** 1.0 mm to 100 mm OD * **Wall Thickness:** 0.1 mm to 5.0 mm * **Length:** Standard 1-4 meters, custom lengths available * **Tolerance:** OD ±0.1 mm (<10 mm), ±0.5% (>10 mm) * **Wall Tolerance:** ±10% standard, ±5% available * **Surface Finish:** 1.6 μm Ra standard, 0.8 μm Ra available **Types Available:** * **Seamless Tube:** For high-integrity applications * **Drawn Tube:** Precision dimensional control * **Welded & Redrawn Tube:** Economical precision tubing * **Pre-oxidized Tube:** Ready for immediate glass sealing * **Copper-Plated Tube:** Enhanced glass wetting characteristics **Primary Applications:** **Electronics & Vacuum Applications:** * **Electronic Tube Components:** Anode caps, grid supports, and envelope sections * **Vacuum Feedthroughs:** Hermetic passages for electrical and mechanical connections * **Microwave Tube Parts:** Cavity resonators and waveguide components * **Semiconductor Equipment:** Gas distribution lines and process chamber components **Industrial & Scientific Applications:** * **Optical Instrumentation:** Laser tube housings and optical bench components * **Laboratory Apparatus:** Specialized glass-to-metal seal assemblies * **Sensor Protection Tubes:** Thermocouple wells and pressure sensor housings * **Medical Device Components:** Endoscope parts and surgical instrument tubing **Aerospace & Defense:** * **Avionics Packaging:** Hermetic connector sleeves and enclosure components * **Satellite Systems:** Space-qualified electronic package components * **Military Electronics:** Radar system waveguides and housing elements --- #### **5. International Standards** Comprehensive international specifications for tube products. | Standard Type | Standard Number | Title / Specification | |:---|:---|:---| | **ASTM** | **ASTM F15** | Standard Specification for Iron-Nickel Sealing Alloys | | **UNS** | **K94800** | Unified Numbering System Designation | | **AMS** | AMS 7722 | Aerospace Material Specification | | **ASTM** | ASTM B751 | Standard Specification for Nickel Alloy Seamless Tube | | **DIN** | DIN 1745 | Metallic Materials for Glass-to-Metal Seals | | **ISO** | ISO 9711 | Metallic Materials for Glass-to-Metal Seals | | **ASME** | SB-751 | Seamless Nickel Alloy Tubes | --- #### **6. Manufacturing & Processing** **Fabrication Characteristics:** * **Tube Drawing:** Excellent drawability with proper annealing cycles * **Bending:** Minimum bend radius 2x OD for thin walls, 3x OD for thick walls * **Machining:** Good machinability with carbide tools and adequate cooling * **Welding:** TIG and laser welding suitable with proper procedures **Glass Sealing Preparation:** * **Surface Preparation:** Critical cleaning and surface activation * **Oxide Control:** Controlled pre-oxidation for optimal glass adhesion * **Thermal Management:** Controlled heating/cooling rates during sealing process * **Sealing Parameters:** 900-1000°C in controlled atmosphere **Quality Control:** * **Dimensional Verification:** OD, wall thickness, and concentricity measurement * **Surface Quality:** Visual and microscopic examination * **Leak Testing:** Helium leak testing to 1 × 10⁻⁹ atm·cc/s * **Metallurgical Quality:** Grain structure and inclusion assessment --- #### **7. Design Considerations** **Wall Thickness Selection:** * **Ultra-Thin Wall (0.1-0.5 mm):** For miniature electronic components * **Thin Wall (0.5-1.5 mm):** For standard electronic and instrument applications * **Medium Wall (1.5-3.0 mm):** For structural and pressure applications * **Heavy Wall (3.0-5.0 mm):** For high-pressure and mechanical applications **End Configurations:** * **Plain Cut:** Standard square-cut ends * **Expanded/Reduced Ends:** For special connection requirements * **Flared Ends:** For mechanical joining applications * **Machined Ends:** Precision machined for specific sealing requirements --- **Summary** **Alloy 48 (Nilo 48) Tube (UNS K94800)** provides precision tubular solutions for applications requiring exact dimensional control and reliable hard glass-to-metal seals. Its carefully matched thermal expansion properties with borosilicate and other hard glasses, combined with excellent forming characteristics and consistent quality, make it indispensable for critical applications in electronics, aerospace, medical devices, and scientific instrumentation. The tube form enables the creation of sophisticated hermetic assemblies where precise dimensional control and reliable thermal expansion matching are essential. Compliance with **ASTM F15** and other international standards ensures material consistency and performance reliability for demanding applications across multiple high-technology industries.

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 2499 gallon liquid totes Special package is available on request.