Kovar,Nilo-K Tube,UNS K94610,E FORU

British Specs:，American Specs: ASTM F15 ASTM F26 AMS 7726 Wire AMS 7727 Bar and Forgings AMS 7728 Sheet, Strip and Plate MIL-I-23011 Class 1，German Specs:WS 1.3981,AFNOR NF A54-301

**Technical Data Sheet: Kovar® / Nilo-K Tube (UNS K94610)** **1.0 Product Overview** Kovar Tube (also known as Nilo-K Tube), designated as **UNS K94610**, is a nickel‑cobalt‑iron controlled expansion alloy manufactured in tubular form with precise dimensional control. This specialized product maintains thermal expansion characteristics that closely match hard glass and ceramics, making it essential for applications requiring reliable thermal compatibility, hermetic sealing, and precise dimensional stability in electronic, aerospace, and scientific instrumentation. --- **2.0 Chemical Composition (wt%)** | Element | Content (%) | Primary Function | |---------|-------------|------------------| | **Ni** | 28.5–29.5 | Controls thermal expansion coefficient | | **Co** | 16.8–17.8 | Fine-tunes expansion match with glass/ceramics | | **Fe** | Balance | Base element | | **Mn** | 0.20–0.50 | Deoxidizer and improves drawability | | **Si** | 0.10–0.30 | Deoxidizer and enhances manufacturing | | **C** | ≤ 0.02 | Minimizes carbide formation | | **Al** | ≤ 0.05 | Deoxidizer | | **P** | ≤ 0.02 | Impurity control | | **S** | ≤ 0.02 | Impurity control | --- **3.0 Physical Properties** | Property | Value (Metric) | Value (Imperial) | Condition | |----------|----------------|------------------|-----------| | Density | 8.36 g/cm³ | 0.302 lb/in³ | 20°C | | Melting Range | 1440–1460°C | 2624–2660°F | – | | Thermal Conductivity | 17.3 W/m·K | 120 Btu·in/(hr·ft²·°F) | 20°C | | Mean CTE (30–400°C) | 5.1 ×10⁻⁶/°C | 2.8 ×10⁻⁶/°F | Matching borosilicate glass | | Electrical Resistivity | 0.49 μΩ·m | 19.0 μΩ·in | 20°C | | Modulus of Elasticity | 138 GPa | 20.0 ×10⁶ psi | 20°C | | Curie Temperature | 435°C | 815°F | – | | Specific Heat | 0.46 J/g·°C | 0.11 Btu/lb·°F | 20°C | --- **4.0 Mechanical Properties** **4.1 Typical Properties (Annealed Condition)** - **Tensile Strength**: 520–590 MPa (75–85 ksi) - **Yield Strength (0.2% Offset)**: 350–420 MPa (51–61 ksi) - **Elongation**: 25–35% - **Hardness**: 68–82 HRB - **Collapse Pressure**: 1.5–3.0 × working pressure **4.2 Cold Worked Condition** - **Tensile Strength**: 620–760 MPa (90–110 ksi) - **Yield Strength**: 550–690 MPa (80–100 ksi) - **Elongation**: 15–25% - **Hardness**: 85–100 HRB --- **5.0 Product Specifications** **5.1 Standard Tube Sizes** - **Outside Diameter**: 0.5 mm to 100 mm (0.020" to 4.0") - **Wall Thickness**: 0.1 mm to 5 mm (0.004" to 0.200") - **Length**: Up to 6000 mm (240") - **Diameter Tolerance**: ±0.02 mm for OD < 10 mm - **Wall Thickness Tolerance**: ±5% of nominal thickness **5.2 Manufacturing Methods** - Seamless cold drawing - Welded and redrawn - Pilger mill processing - Centerless grinding and finishing --- **6.0 Manufacturing Processes** **6.1 Production Methods** - Cold drawing over mandrel for seamless tubing - Precision welding with subsequent cold working - Intermediate annealing in hydrogen atmosphere - Final sizing and straightening - Surface finishing and cleaning **6.2 Quality Control** - Eddy current testing for defect detection - Ultrasonic wall thickness measurement - Dimensional verification - Surface quality inspection - Pressure testing when specified --- **7.0 Heat Treatment** **7.1 Solution Annealing** - **Temperature**: 850–900°C (1560–1650°F) - **Atmosphere**: Hydrogen or vacuum required - **Time**: 15–30 minutes at temperature - **Cooling**: Rapid cool to 400°C, then air cool **7.2 Stress Relieving** - **Temperature**: 425–540°C (800–1000°F) - **Time**: 20–40 minutes - **Atmosphere**: Protective atmosphere recommended - **Application**: After forming or machining operations --- **8.0 Applications** **8.1 Electronics & Semiconductor** - Microwave tube components - X-ray tube housings - Laser diode packages - Vacuum interrupter envelopes - Semiconductor process chamber parts **8.2 Aerospace & Defense** - Waveguide tubing - Satellite structural components - Gyroscope housings - Radar system elements - Avionics cooling systems **8.3 Scientific & Medical** - Electron microscope columns - Mass spectrometer components - NMR probe tubing - Medical laser housings - Laboratory instrument frames --- **9.0 International Standards & Specifications** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F15** | ASTM | Iron-Nickel-Cobalt Sealing Alloy | | **ASTM B774** | ASTM | Thin-Wall Seamless Pipe and Tube | | **UNS K94610** | ASTM | Unified Numbering System | | **DIN 1.3981** | DIN | German Material Number | | **AMS 7724** | SAE | Bars, Rods, and Wire Forms | | **MIL-I-23011** | U.S. Military | Sealing Alloys | --- **10.0 Fabrication & Processing** **10.1 Machining Guidelines** - Good machinability in annealed condition - Use carbide tools with positive rake angles - Recommended cutting speed: 25–40 m/min - Use soluble oil coolants for optimal finish - Suitable for turning, boring, and facing operations **10.2 Welding & Joining** - Excellent weldability using GTAW process - Recommended filler: Matching Kovar composition - Pre-heat not required for thin sections - Post-weld stress relief recommended **10.3 Bending & Forming** - Can be cold formed with proper tooling - Minimum bend radius: 1.5 × OD - Mandrel bending for tight radii and thin walls - Springback compensation required --- **11.0 Performance Characteristics** **11.1 Thermal Performance** - Excellent expansion match with borosilicate glass - Minimal thermal stress during cycling - Stable dimensional characteristics to 400°C - Good thermal shock resistance **11.2 Sealing & Vacuum Performance** - Excellent hermetic sealing capabilities - Suitable for ultra-high vacuum applications - Low outgassing characteristics - Compatible with various sealing methods --- **12.0 Quality Assurance** **12.1 Testing & Certification** - **Non-Destructive Testing**: Eddy current, ultrasonic, or radiographic - **Dimensional Inspection**: To ASTM B774 specifications - **Material Certification**: EN 10204 3.1 with full traceability - **Pressure Testing**: When specified for pressure applications - **Surface Finish**: Verification per customer requirements **12.2 Special Features** - Precise dimensional control - Excellent surface finish options - Custom sizes and configurations - Special cleaning and packaging available Kovar/Nilo-K Tube (UNS K94610) provides exceptional thermal expansion matching capabilities in tubular form, enabling reliable performance in applications requiring exact dimensional stability and thermal compatibility. Its unique combination of properties makes it indispensable for critical electronic, aerospace, and scientific applications where conventional materials would fail due to thermal mismatch or inadequate performance in demanding environments.

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 2369 gallon liquid totes Special package is available on request.