Kovar,Alloy K Strip,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 Strip (UNS K94610)** **1.0 Product Overview** Kovar Strip (Alloy K Strip), designated as **UNS K94610**, is a nickel‑cobalt‑iron controlled expansion alloy supplied in thin strip form. This precision-engineered material features a thermal expansion coefficient carefully matched to hard glass and ceramics, making it ideal for high-volume production of electronic components, hermetic seals, and precision instruments requiring exact dimensional stability across temperature variations. --- **2.0 Chemical Composition (wt%)** | Element | Content (%) | Function | |---------|-------------|----------| | **Ni** | 28.5–29.5 | Controls thermal expansion rate | | **Co** | 16.8–17.8 | Matches glass/ceramic expansion | | **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 CTE | 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**: 515–585 MPa (75–85 ksi) - **Yield Strength (0.2% Offset)**: 345–415 MPa (50–60 ksi) - **Elongation**: 30–40% - **Hardness**: 65–80 HRB - **Modulus of Elasticity**: 138 GPa (20.0 ×10⁶ psi) **4.2 Cold Rolled Tempers** | Temper | Tensile Strength | Yield Strength | Elongation | Hardness | |--------|------------------|----------------|------------|----------| | **¼ Hard** | 550–655 MPa | 450–550 MPa | 20–30% | 80–95 HRB | | **½ Hard** | 620–725 MPa | 550–655 MPa | 12–22% | 95–105 HRB | | **Full Hard** | 690–790 MPa | 655–760 MPa | 5–15% | 100–110 HRB | --- **5.0 Product Specifications & Sizes** **5.1 Standard Strip Dimensions** - **Thickness**: 0.05 mm to 2.0 mm (0.002" to 0.080") - **Width**: 2 mm to 300 mm (0.080" to 12.0") - **Coil Weight**: Up to 500 kg (1100 lbs) - **Thickness Tolerance**: ±0.005 mm for thickness < 0.5 mm - **Width Tolerance**: ±0.02 mm for widths < 50 mm **5.2 Available Conditions & Finishes** - Annealed (dead soft) - ¼ Hard, ½ Hard, Full Hard tempers - Bright annealed surface - Cold rolled finish - Special edge conditions (slit, sheared, deburred) --- **6.0 Heat Treatment** **6.1 Full 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 **6.2 Stress Relieving** - Temperature: 425–540°C (800–1000°F) - Time: 20–40 minutes - Atmosphere: Air or protective atmosphere --- **7.0 Applications** **7.1 Electronic Components** - Lead frame substrates - IC package lids and covers - Transistor mounting strips - Microelectronic connector elements - RF shield components **7.2 Sealing Applications** - Glass-to-metal seal ribbons - Ceramic package sealing frames - Hermetic connector elements - Optical window mounting strips - Vacuum feedthrough components **7.3 Precision Instruments** - Scale and encoder strips - Precision spring elements - Instrument frame components - Optical mounting strips - Laboratory equipment parts --- **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 Stamping & Blanking** - Excellent stamping characteristics in annealed condition - Progressive die capability - Clean, burr-free edges - Consistent springback control **9.2 Forming & Bending** - Superior formability in annealed temper - Minimum bend radius: 0.5T (where T = thickness) - Good spring properties in hardened tempers - Suitable for complex formed shapes **9.3 Welding & Joining** - Excellent weldability using resistance welding - GTAW and laser welding suitable - Brazing with silver-based alloys - Epoxy bonding with proper surface preparation **9.4 Etching & Photochemical Machining** - Suitable for photochemical etching - Clean, precise edge definition - Compatible with standard etchants - Good for fine feature reproduction --- **10.0 Quality Assurance** **10.1 Testing & Certification** - **Certification**: EN 10204 3.1 Material Certificates - **Dimensional Control**: - Continuous thickness monitoring - Width and edge quality verification - Camber and flatness measurement - **Mechanical Testing**: - Tensile testing per ASTM E8 - Hardness verification - Springback characteristics - **Surface Quality**: - Surface roughness measurement - Defect-free surface requirement - Oxide-free condition for critical applications **10.2 Special Features** - Consistent gauge control throughout coil length - Uniform mechanical properties - Optimized for high-speed stamping operations - Available in precision slit widths - Custom tempers for specific applications Kovar Strip (UNS K94610) provides exceptional thermal expansion matching in a precision strip form, enabling high-volume manufacturing of components requiring exact dimensional stability and reliable performance in temperature-varying environments. Its combination of consistent quality, excellent fabrication characteristics, and unique thermal properties makes it the material of choice for critical electronic, aerospace, and instrumentation applications.

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 2359 gallon liquid totes Special package is available on request.