Expansion Alloy Rod
Your Trusted Source for Precision Alloy Manufacturing
Expansion alloys are specialized materials designed to exhibit controllable thermal expansion properties. These alloys are widely used in applications where the thermal expansion needs to match or remain stable with other materials, such as glass, ceramics, or specific industrial components, or when a specific expansion must be met over a certain temperature range.
Available grades: 4J29, 4J32, 4J33, 4J50, 4J42
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Plate / Sheet
- Thickness: 0.1mm-50mm
- Width: 50mm-1000mm
- Length: 1000mm-6000mm
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Strip
- Thickness: 0.02mm-1mm
- Width: 3mm-500mm
- Delivery Forms: Bright shiny surface or anodized surface, supplied in spools or cut-to-length
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Rod
- Diameter: Ø3mm-Ø100mm
- Length: 100mm-2000mm
- Delivery Forms: Hot rolled, forged or turned
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Wire
- Diameter: Ø0.03mm-Ø6mm
- Delivery Forms: Bright shiny or anodized, supplied in spools
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Tube
- Outer Diameter: Ø3mm-Ø200mm
- Wall Thickness: 0.5mm-10mm
- Length: 100mm-6000mm
Chemical Composition
| Elements | 4J29 | 4J36 | |
| Carbon (C) | Not greater than | 0.03 | 0.05 |
| Sulfur (S) | 0.02 | 0.02 | |
| Phosphorus (P) | 0.02 | 0.02 | |
| Manganese (Mn) | ≤0.50 | 0.20-0.60 | |
| Silicon (Si) | ≤0.30 | ≤0.30 | |
| Nickel (Ni) | 28.5-29.5 | 35.0-37.0 | |
| Chromium (Cr) | - | - | |
| Cobalt (Co) | 16.8-17.8 | - | |
| Iron (Fe) | Rest | Rest | |
| Other Elements |
Thermal Expansion Properties
| Alloy Grade | 20°C-100°C | 20°C-300°C | 20°C-500°C |
| 4J36 Invar Alloy | 1.2×10⁻⁶ /°C | 2.5×10⁻⁶ /°C | - |
| 4J29 Kovar Alloy | 4.6×10⁻⁶ /°C | 5.5×10⁻⁶ /°C | 6.2×10⁻⁶ /°C |
Mechanical Properties
| Alloy Grade | 4J36 Invar Alloy | 4J29 Kovar Alloy |
| Density (g/cm³) | 8.1 | 8.2 |
| Tensile Strength (MPa) | 500-600 | 600-700 |
| Yield Strength (MPa) | 250-350 | 300-400 |
| Hardness (HV) | 150-200 | 200-250 |
Electrical Properties
| Alloy Grade | 4J36 Invar Alloy | 4J29 Kovar Alloy |
| Electrical Resistivity (10⁻⁶ Ω·cm) | 80 | 50 |
| Thermal Conductivity (W/m·K) | 10-12 | 16-18 |
Features
- Some expansion alloys, such as Invar alloys, expand almost not at all with temperature changes, while other types can be engineered to have a specific expansion rate.
- These alloys maintain shape and size stability, even in environments with significant temperature fluctuations.
- They typically offer enough strength and toughness, making them suitable for complex structural components.
- They are easy to process with cold and hot working, welding, and other forming techniques.
- Many expansion alloys also exhibit excellent corrosion resistance.
Applications
- Precision instruments and measuring devices: such as balances, microscopes, and laser interferometers
- Electronics and semiconductors: integrated circuit boards, connectors, resistors, etc.
- Aerospace: navigation systems, control systems on aircraft and satellites
- Automotive industry: engine sensors, exhaust system components
- Energy industry: sensitive equipment in nuclear power plants, thermal power stations, such as instrument panels and controllers
- Watchmaking: precision components such as gears and mainsprings in high-end watches
- Lighting industry: metal brackets and connectors in light bulbs and LED lighting fixtures
Packaging
Our Expansion Alloy