Kovar,Rodar Bar(Round bar, Flat bar),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® / Rodar® Bar (Round Bar & Flat Bar) UNS K94610** **1.0 Product Overview** Kovar Bar (commercially known as Rodar Bar), designated as **UNS K94610**, is a nickel‑cobalt‑iron controlled expansion alloy supplied in both round bar and flat bar configurations. These product forms maintain precise thermal expansion characteristics matching hard glass and ceramics, providing excellent machinability and fabrication versatility for components requiring reliable thermal compatibility in demanding applications. --- **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 workability | | **Si** | 0.10–0.30 | Deoxidizer and enhances hot workability | | **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 Annealed Condition (Typical)** - **Tensile Strength**: 520–590 MPa (75–85 ksi) - **Yield Strength (0.2% Offset)**: 350–420 MPa (51–61 ksi) - **Elongation**: 25–35% - **Reduction in Area**: 45–60% - **Hardness**: 68–82 HRB - **Modulus of Elasticity**: 138 GPa (20.0 ×10⁶ psi) **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 Round Bar Specifications** - **Diameter Range**: 3.0 mm to 200 mm (0.125" to 8.0") - **Length**: 1000 mm to 3000 mm (39" to 118") - **Diameter Tolerance**: h9 for precision applications - **Straightness**: 0.5 mm per 300 mm maximum - **Surface Finish**: Centerless ground, turned, or hot rolled **5.2 Flat Bar Specifications** - **Thickness**: 3.0 mm to 50 mm (0.125" to 2.0") - **Width**: 10 mm to 200 mm (0.375" to 8.0") - **Length**: 1000 mm to 3000 mm (39" to 118") - **Flatness**: 0.1 mm per 100 mm maximum - **Edge Condition**: Sheared, sawn, or ground --- **6.0 Manufacturing Processes** **6.1 Production Methods** - Hot rolling from forged billets - Cold drawing for improved surface finish - Centerless grinding for tight tolerances - Annealing in hydrogen or vacuum atmosphere - Precision sawing and cutting **6.2 Quality Control** - Ultrasonic testing per ASTM A388 - Dimensional verification - Surface quality inspection - Mechanical property testing - Chemical analysis verification --- **7.0 Heat Treatment** **7.1 Solution Annealing** - **Temperature**: 850–900°C (1560–1650°F) - **Atmosphere**: Hydrogen or vacuum required - **Time**: 30–90 minutes depending on section size - **Cooling**: Rapid cool to 400°C, then air cool **7.2 Stress Relieving** - **Temperature**: 425–540°C (800–1000°F) - **Time**: 60–120 minutes - **Atmosphere**: Air or protective atmosphere - **Application**: Recommended after heavy machining --- **8.0 Applications** **8.1 Round Bar Applications** - Semiconductor lead frame pins - Electronic package structural members - Microwave component mounts - Vacuum feedthrough conductors - Optical mounting posts and shafts **8.2 Flat Bar Applications** - Power semiconductor bases - Circuit board mounting rails - Laser housing frames and chassis - Instrument structural components - Heat sink mounting plates **8.3 Industry Specific Uses** - **Electronics**: IC package components, connector bases - **Aerospace**: Avionics mounts, satellite structural members - **Medical**: X-ray tube parts, medical instrument frames - **Telecommunications**: RF package bases, waveguide supports --- **9.0 International Standards & Specifications** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F15** | ASTM | Iron-Nickel-Cobalt Sealing Alloy | | **AMS 7724** | SAE | Bars, Rods, and Wire Forms | | **UNS K94610** | ASTM | Unified Numbering System | | **DIN 1.3981** | DIN | German Material Number | | **JIS H 4551** | JIS | Japanese Industrial Standard | | **GB 4J29** | China | Chinese National Standard | --- **10.0 Machining & Fabrication** **10.1 Machining Characteristics** - Good machinability in annealed condition - Use carbide tools with positive rake angles - Recommended cutting speed: 25–40 m/min - Use soluble oil or chemical coolants - Moderate work hardening tendency requires sharp tools **10.2 Turning & Milling** - **Roughing**: Depth of cut 2–5 mm, feed 0.2–0.5 mm/rev - **Finishing**: Depth of cut 0.5–1.5 mm, feed 0.1–0.3 mm/rev - **Surface Speed**: 30–45 m/min for carbide tools **10.3 Grinding & Cutting** - Suitable for surface and cylindrical grinding - Abrasive cutting effective for bar stock - EDM machining possible for complex shapes - Laser and waterjet cutting available --- **11.0 Performance Characteristics** **11.1 Thermal Expansion Match** - Excellent compatibility with borosilicate glass (Pyrex) - Matches 96% alumina ceramic expansion characteristics - Minimal thermal stress during temperature cycling - Stable dimensional performance from cryogenic to 400°C **11.2 Glass Sealing Preparation** - Clean and degrease before sealing operations - Controlled oxidation at 700–800°C for optimal glass bonding - Surface activation essential for strong hermetic seals - Avoid contamination before sealing processes --- **12.0 Quality Assurance** **12.1 Testing & Certification** - Chemical composition analysis - Thermal expansion coefficient verification - Mechanical property testing - Ultrasonic testing for internal quality - Dimensional accuracy certification **12.2 Documentation & Traceability** - Mill Test Certificates per EN 10204 3.1 - Full material traceability from melt to finished bar - Heat treatment records and certifications - Compliance with customer and industry specifications Kovar/Rodar Bar (UNS K94610) in both round and flat configurations provides manufacturers with versatile raw materials for producing precision components requiring exact thermal expansion matching with glass and ceramics. The availability in different bar forms enables efficient manufacturing of components for electronic packaging, aerospace systems, and scientific instruments where reliable thermal performance and dimensional stability are critical requirements.

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 2380 gallon liquid totes Special package is available on request.