Kovar,Rodar Pipe,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® Pipe (UNS K94610)** **1.0 Product Overview** Kovar Pipe (commercially known as Rodar Pipe), designated as **UNS K94610**, is a nickel‑cobalt‑iron controlled expansion alloy manufactured in tubular form. This specialized product maintains precise thermal expansion characteristics matching hard glass and ceramics, making it essential for vacuum systems, electronic packages, and scientific instruments where reliable thermal compatibility and hermetic sealing are critical requirements. --- **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 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 (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 - **Bursting Pressure**: 2.5 × working pressure **4.2 Pressure-Temperature Ratings** - **Maximum Working Pressure**: 100 bar (1450 psi) at 20°C - **Temperature Limit**: 400°C (750°F) for continuous service - **Pressure Derating**: Required above 300°C (570°F) --- **5.0 Product Specifications** **5.1 Standard Pipe Sizes** - **Outside Diameter**: 6 mm to 150 mm (0.25" to 6.0") - **Wall Thickness**: 0.5 mm to 12 mm (0.020" to 0.50") - **Length**: 500 mm to 3000 mm (20" to 118") - **Tolerance**: Per ASTM B774 for thin wall tubing - **Straightness**: 1 mm per 300 mm maximum **5.2 Manufacturing Methods** - Seamless cold drawing - Welded and redrawn - Centrifugal casting (special sizes) - Machined from solid bar (custom applications) --- **6.0 Manufacturing Processes** **6.1 Production Methods** - Cold drawing over mandrel for seamless tubing - Pilger milling process for precise wall thickness - Annealing in hydrogen atmosphere - Final sizing and straightening operations - Non-destructive testing and inspection **6.2 Quality Control** - Eddy current testing for defect detection - Hydrostatic pressure testing - Dimensional verification - Surface quality inspection - Ultrasonic thickness measurement --- **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 bending or forming operations --- **8.0 Applications** **8.1 Electronics & Semiconductor** - Vacuum tube envelopes and structures - Microwave tube bodies and components - X-ray tube housings and anodes - Laser enclosure tubes and mounts - Semiconductor process chamber components **8.2 Aerospace & Defense** - Satellite structural tubing and frames - Gyroscope housing components - Radar waveguide tubing - Avionics cooling jackets - Space telescope structural members **8.3 Scientific & Research** - Electron microscope columns - Mass spectrometer tubing - Nuclear magnetic resonance probes - Cryogenic transfer lines - Vacuum system components and chambers --- **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 & Installation** **10.1 Machining & Processing** - Good machinability in annealed condition - Use carbide tools with positive rake angles - Recommended cutting speed: 25–40 m/min - Suitable for turning, boring, and facing operations - EDM machining possible for complex features **10.2 Welding & Joining** - Excellent weldability using GTAW (TIG) process - Recommended filler: Matching composition wire - Pre-heat not required for thin wall sections - Post-weld stress relief at 425–540°C recommended **10.3 Bending & Forming** - Can be cold formed with proper tooling - Minimum bend radius: 2 × OD for thin wall tubing - Mandrel bending recommended for tight radii - Stress relieve after severe forming operations --- **11.0 Performance Characteristics** **11.1 Thermal Performance** - Excellent thermal expansion match with borosilicate glass - Minimal thermal stress during temperature cycling - Stable dimensional characteristics to 400°C - Good thermal shock resistance **11.2 Vacuum & Sealing Performance** - Excellent vacuum tightness characteristics - Suitable for ultra-high vacuum applications - Low outgassing rates in vacuum service - Compatible with various sealing techniques --- **12.0 Quality Assurance** **12.1 Testing & Certification** - **Pressure Testing**: Hydrostatic or pneumatic per applicable standards - **Non-Destructive Examination**: Eddy current, ultrasonic, or radiographic - **Dimensional Inspection**: To ASTM B774 or customer specifications - **Material Certification**: EN 10204 3.1 with full traceability - **Surface Finish**: Per customer requirements and application needs **12.2 Marking & Identification** - Material grade (K94610) - Size and wall thickness - Manufacturer's identification - Heat number for traceability - Compliance markings as required Kovar/Rodar Pipe (UNS K94610) provides reliable performance in applications requiring exact thermal expansion matching with glass and ceramic components. Its ability to maintain dimensional stability and create leak-tight connections in temperature-varying environments makes it essential for critical vacuum, electronic packaging, and scientific applications where conventional materials would fail due to thermal mismatch or inadequate performance characteristics.

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 2381 gallon liquid totes Special package is available on request.