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

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

### **Alloy 48 (Nilo 48) - Pipe Product Overview** **Alloy 48**, commercially known as **Nilo 48**, is a controlled expansion iron-nickel alloy specifically engineered for matched sealing with hard glasses such as borosilicate and alumina-silicate types. The **Pipe** form provides tubular components for applications requiring hermetic glass-to-metal seals in cylindrical configurations, offering both structural integrity and precise thermal expansion compatibility. * **UNS Designation:** **K94800** * **Common Names:** Nilo 48 Pipe, Glass Sealing 48 Tubing --- #### **1. Chemical Composition** Precisely controlled chemistry ensures consistent thermal performance in pipe form. | Element | Percentage (%) | Role in the Alloy | |:---|:---|:---| | **Nickel (Ni)** | 47.5 - 48.5 | Controls CTE characteristics and Curie point | | **Iron (Fe)** | Balance | Base structural element | | **Manganese (Mn)** | 0.10 - 0.30 | Enhances manufacturability and hot workability | | **Silicon (Si)** | 0.10 - 0.30 | Improves glass wetting and sealing performance | | **Carbon (C)** | 0.05 max | Limited for optimal welding and forming characteristics | | **Sulfur (S)** | 0.02 max | Controlled impurity | | **Phosphorus (P)** | 0.02 max | Controlled impurity | --- #### **2. Physical Properties** Specialized properties optimized for pipe 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 expansion | | **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)** **Pipe 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) * **Burst Pressure:** Varies with wall thickness and diameter --- #### **4. Product Specifications & Applications** **Pipe Specifications:** * **Diameter Range:** 6 mm to 200 mm OD * **Wall Thickness:** 0.5 mm to 12 mm * **Length:** Standard 3-6 meters, custom lengths available * **Tolerance:** OD ±0.5%, Wall ±10% * **Surface Finish:** 3.2 μm Ra standard, 1.6 μm Ra available **Types Available:** * **Seamless Pipe:** For high-pressure and vacuum applications * **Welded Pipe:** Economical option for general applications * **Pre-oxidized Pipe:** Ready for immediate glass sealing * **Copper-Plated Pipe:** Enhanced glass wetting characteristics **Primary Applications:** **Electronics & Vacuum Applications:** * **Electronic Tube Envelopes:** Main structural bodies for power tubes and transmitter tubes * **Vacuum Chamber Components:** Ports, connectors, and structural elements * **Microwave Tube Housings:** Waveguide components and resonator cavities * **Semiconductor Equipment:** Process chamber components and gas distribution systems **Industrial & Scientific Applications:** * **Optical System Housings:** Laser tube bodies and optical instrument enclosures * **Laboratory Equipment:** Specialized apparatus requiring glass-to-metal seals * **Sensor Housings:** Protection tubes for temperature and pressure sensors * **Medical Device Components:** Implantable device housings and diagnostic equipment **Aerospace & Defense:** * **Avionics Packaging:** Hermetic enclosures for aircraft electronics * **Satellite Components:** Space-qualified electronic packages * **Military Electronics:** Radar system components and communication equipment --- #### **5. International Standards** Comprehensive international specifications for pipe 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 B829 | Standard Specification for Seamless Nickel Alloy Pipe | | **DIN** | DIN 1745 | Metallic Materials for Glass-to-Metal Seals | | **ISO** | ISO 9711 | Metallic Materials for Glass-to-Metal Seals | | **ASME** | SB-829 | Seamless Nickel and Nickel Alloy Pipe | --- #### **6. Manufacturing & Processing** **Fabrication Characteristics:** * **Machining:** Good machinability with proper tool geometry and cooling * **Bending:** Capable of cold bending with minimum bend radius of 3x OD * **Welding:** Excellent weldability using TIG, plasma, or laser methods * **Flaring/Flanging:** Suitable for end preparation and connection interfaces **Glass Sealing Preparation:** * **Surface Cleaning:** Critical removal of oils and contaminants * **Surface Activation:** Controlled oxidation or copper plating * **Thermal Cycling:** Controlled heating and cooling rates during sealing * **Sealing Temperature:** 900-1000°C for optimal glass bonding **Quality Control:** * **Dimensional Inspection:** OD, wall thickness, and ovality verification * **Surface Examination:** Visual and microscopic surface quality assessment * **Leak Testing:** Helium mass spectrometry for vacuum applications * **Metallurgical Testing:** Grain structure and inclusion assessment --- #### **7. Design Considerations** **Wall Thickness Selection:** * **Thin Wall (0.5-1.5 mm):** For lightweight electronic envelopes * **Standard Wall (1.5-4.0 mm):** General purpose applications * **Heavy Wall (4.0-12.0 mm):** For high-pressure and structural applications **End Preparation:** * **Square Cut:** Basic preparation for simple seals * **Bevelled Ends:** For specialized sealing configurations * **Flanged Ends:** For mechanical attachment requirements * **Special Profiles:** Custom machined ends for specific applications --- **Summary** **Alloy 48 (Nilo 48) Pipe (UNS K94800)** provides a critical tubular solution for applications requiring reliable hard glass-to-metal seals in cylindrical configurations. Its precisely matched thermal expansion properties with borosilicate and other hard glasses, combined with excellent manufacturability and consistent quality, make it essential for electronic tubes, vacuum systems, optical devices, and high-reliability industrial equipment. The pipe form enables the creation of complex hermetic assemblies where glass must be sealed to cylindrical metal surfaces, maintaining integrity under thermal cycling conditions. Compliance with **ASTM F15** and other international standards ensures material consistency and performance reliability for the most demanding applications in aerospace, medical, semiconductor, and scientific 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 2498 gallon liquid totes Special package is available on request.