Kovar,Alloy 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® / Alloy K Tube (UNS K94610)** **1.0 Product Overview** Kovar Tube (Alloy K Tube), designated as **UNS K94610**, is a nickel‑cobalt‑iron low expansion alloy produced in tubular form. Its thermal expansion coefficient is carefully matched to hard glass (such as borosilicate) and certain ceramics, enabling reliable hermetic seals in electronic packages, vacuum systems, and high‑precision instruments operating across wide temperature ranges. --- **2.0 Chemical Composition (wt%)** | Element | Content (%) | Function | |---------|-------------|----------| | **Ni** | 28.5–29.5 | Controls thermal expansion | | **Co** | 16.8–17.8 | Matches glass/ceramic expansion | | **Fe** | Balance | Base metal | | **Mn** | 0.20–0.50 | Deoxidizer | | **Si** | 0.10–0.30 | Deoxidizer | | **C** | ≤ 0.02 | Minimizes carbide formation | | **Al** | ≤ 0.05 | Deoxidizer | | **P, S**| ≤ 0.02 each | Impurity control | --- **3.0 Physical Properties** | Property | Value (Metric) | Value (Imperial) | Condition | |----------|----------------|------------------|-----------| | Density | 8.36 g/cm³ | 0.302 lb/in³ | RT | | Melting Point | ~1450°C | ~2640°F | – | | Thermal Conductivity | 17.3 W/m·K | 120 Btu·in/(hr·ft²·°F) | 20°C | | Mean CTE | 4.9–5.5 ×10⁻⁶/°C | 2.7–3.1 ×10⁻⁶/°F | 20–400°C | | Electrical Resistivity | 0.49 μΩ·m | 19.0 μΩ·in | 20°C | | Modulus of Elasticity | 138 GPa | 20.0 ×10⁶ psi | RT | | Curie Temperature | 435°C | 815°F | – | --- **4.0 Mechanical Properties** **4.1 Typical Properties (Annealed Condition)** - **Tensile Strength**: 517–586 MPa (75–85 ksi) - **Yield Strength (0.2% Offset)**: 345–414 MPa (50–60 ksi) - **Elongation**: 25–35% - **Hardness**: 65–80 HRB **4.2 Cold Worked Condition** - **Tensile Strength**: 586–758 MPa (85–110 ksi) - **Yield Strength**: 483–620 MPa (70–90 ksi) - **Elongation**: 10–20% --- **5.0 Product Specifications & Sizes** **5.1 Available Forms & Dimensions** - **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") - **Tolerances**: Per ASTM B774 for seamless thin‑wall tubing **5.2 Manufacturing Methods** - Seamless cold drawing - Welded & redrawn (WR) - Annealed in hydrogen or vacuum atmosphere --- **6.0 Heat Treatment** - **Annealing**: 850–900°C (1560–1650°F) in H₂ or vacuum, followed by rapid cooling to 400°C then air cooling. - **Stress Relieving**: 425–540°C (800–1000°F) for 30–60 minutes. --- **7.0 Applications** - **Electronics & Semiconductors**: - Glass-to-metal seal enclosures - Transistor and IC packages - Microwave tube bodies - Laser diode housings - **Aerospace & Defense**: - Waveguide tubes - Satellite structural tubing - Hermetic connector bodies - Cryogenic fluid transfer lines - **Industrial & Scientific**: - Vacuum chamber fixtures - X-ray tube components - Telescope and optical mounting systems - Precision instrument frames --- **8.0 International Standards** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F15** | ASTM | Iron-Nickel-Cobalt Sealing Alloy | | **ASTM B774** | ASTM | Thin-Wall Seamless Pipe & Tube | | **UNS K94610** | ASTM | Unified Numbering System | | **DIN 1.3981** | DIN | German Material Number | | **AMS 7724** | SAE | Bar, Rod, and Wire Forms | | **MIL-I-23011** | U.S. Military | Sealing Alloys | --- **9.0 Fabrication Notes** - **Machining**: Use sharp tools with positive rake; moderate speeds with coolant recommended. - **Welding**: GTAW (TIG) preferred; pre‑clean and use matching filler material. - **Glass Sealing**: Pre-oxidize surface to promote glass wetting and adhesion. - **Brazing**: Compatible with silver‑based brazing alloys in controlled atmospheres. - **Bending**: Can be cold formed with proper tooling; stress relieve after severe deformation. --- **10.0 Quality Assurance** - Certification to **EN 10204 3.1** - Eddy current or ultrasonic testing available - Dimensional and surface inspection - Thermal expansion testing upon request - Full traceability from melt to final product Kovar Tube (UNS K94610) offers exceptional thermal expansion matching capabilities, making it the material of choice for applications where glass, ceramic, and metal components must maintain structural integrity and hermeticity through repeated thermal cycling. Its unique properties ensure reliable performance in some of the most demanding technological 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 2356 gallon liquid totes Special package is available on request.