Kovar,Alloy K Sheet,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 Sheet (UNS K94610)** **1.0 Product Overview** Kovar Sheet (Alloy K Sheet), designated as **UNS K94610**, is a nickel‑cobalt‑iron controlled expansion alloy supplied in thin sheet form. This specialized material is engineered to exhibit a thermal expansion coefficient that closely matches hard glass (such as borosilicate) and alumina ceramics, making it essential for applications requiring precise dimensional stability and reliable glass-to-metal or ceramic-to-metal seals in electronic packaging, aerospace, and precision instrument industries. --- **2.0 Chemical Composition (wt%)** | Element | Content (%) | Function | |---------|-------------|----------| | **Ni** | 28.5–29.5 | Primary control of thermal expansion | | **Co** | 16.8–17.8 | Matches expansion with glass/ceramics | | **Fe** | Balance | Base metal | | **Mn** | 0.20–0.50 | Deoxidizer and improves workability | | **Si** | 0.10–0.30 | Deoxidizer and enhances fluidity | | **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 Coefficient of Thermal Expansion | 5.1 ×10⁻⁶/°C | 2.8 ×10⁻⁶/°F | 30–400°C | | 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 Annealed Condition (Typical)** - **Tensile Strength**: 520–590 MPa (75–85 ksi) - **Yield Strength (0.2% Offset)**: 350–420 MPa (51–61 ksi) - **Elongation**: 28–38% - **Hardness**: 68–82 HRB - **Modulus of Elasticity**: 138 GPa (20.0 ×10⁶ psi) **4.2 Cold Rolled Condition (¼ Hard)** - **Tensile Strength**: 580–690 MPa (84–100 ksi) - **Yield Strength**: 480–580 MPa (70–84 ksi) - **Elongation**: 18–28% - **Hardness**: 85–98 HRB --- **5.0 Product Specifications & Sizes** **5.1 Standard Sheet Dimensions** - **Thickness**: 0.1 mm to 3.0 mm (0.004" to 0.125") - **Width**: 100 mm to 600 mm (4.0" to 24.0") - **Length**: 500 mm to 2000 mm (20" to 80") - **Thickness Tolerance**: ±0.02 mm for thickness < 1.0 mm **5.2 Available Conditions & Finishes** - Annealed (soft) - best for forming - ¼ Hard, ½ Hard, Full Hard tempers - Cold rolled, annealed, and pickled - Bright annealed finish - Ground finish (one or two sides) --- **6.0 Heat Treatment** **6.1 Full Annealing** - Temperature: 850–900°C (1560–1650°F) - Atmosphere: Hydrogen or vacuum recommended - Time: 20–40 minutes at temperature - Cooling: Rapid cool to 400°C, then air cool **6.2 Stress Relieving** - Temperature: 425–540°C (800–1000°F) - Time: 30–60 minutes - Atmosphere: Air or protective atmosphere --- **7.0 Applications** **7.1 Electronics & Semiconductor Packaging** - IC package lids and bases - Microelectronic substrate plates - RF/Microwave housing covers - Power device mounting sheets - Optoelectronic package frames **7.2 Aerospace & Defense Systems** - Satellite electronic housing sheets - Avionics equipment shielding - Radar component substrates - Hermetic connector components - Military electronic enclosure parts **7.3 Scientific & Industrial Instruments** - Vacuum system flange plates - Laser equipment mounting sheets - X-ray window frames - Precision instrument bases - Laboratory equipment components --- **8.0 International Standards** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F15** | ASTM | Iron-Nickel-Cobalt Sealing Alloy | | **UNS K94610** | ASTM | Unified Numbering System | | **DIN 1.3981** | DIN | German Material Number | | **AMS 7724** | SAE | Bars, Rods, and Wire Forms | | **JIS H 4551** | JIS | Japanese Industrial Standard | | **GB/T 15018** | China | Precision Alloy Classification | --- **9.0 Fabrication Characteristics** **9.1 Machining** - Good machinability in annealed condition - Recommended tools: Carbide with positive rake angles - Cutting speed: 30–45 m/min for optimal results - Use soluble oil coolants for improved finish **9.2 Forming & Stamping** - Excellent formability in annealed condition - Minimum bend radius: 1T (where T = thickness) - Suitable for deep drawing operations - Can be stamped and blanked effectively **9.3 Welding & Joining** - Excellent weldability using GTAW process - Recommended filler: Matching Kovar alloy wire - Pre-heat not required for thin sheets - Post-weld stress relief recommended **9.4 Glass Sealing** - Pre-oxidize at 700–800°C in moist atmosphere - Clean surfaces essential before sealing - Compatible with borosilicate glasses - Forms strong, hermetic bonds --- **10.0 Quality Assurance** - **Certification**: EN 10204 3.1 Material Certificates - **Testing**: - Chemical analysis per ASTM E1473 - Mechanical testing per ASTM E8 - Surface quality inspection per ASTM A480 - Flatness verification - **Traceability**: Full material traceability maintained - **Packaging**: Protective interleaving and moisture-proof wrapping Kovar Sheet (UNS K94610) offers exceptional thermal expansion matching capabilities in a thin, formable sheet product. Its unique combination of thermal properties, mechanical characteristics, and fabrication versatility makes it the material of choice for critical applications where reliable performance and dimensional stability are required across varying temperature environments. The sheet form provides designers with flexible solutions for creating complex components that maintain compatibility with glass and ceramic materials.

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 2358 gallon liquid totes Special package is available on request.