Alloy 27 / UNS K92801 / 1.4105 (Modified) / FeCr27

📄 Product Description: Alloy 27 / UNS K92801 — Controlled Expansion Iron-Nickel-Cobalt Alloy

🧾 General Technical Characteristics

Alloy 27, also known as UNS K92801, is a precision-engineered iron-nickel-cobalt alloy designed for applications requiring extremely low and controlled thermal expansion. Its unique composition allows it to closely match the thermal expansion of hard borosilicate glass and certain ceramics, making it ideal for hermetic glass-to-metal seals.

This alloy provides excellent dimensional stability across a wide temperature range and has been widely adopted in the electronics, aerospace, and telecommunications industries.

⚙️ Applications

• Glass-to-metal seals
• Semiconductor packaging
• Ceramic-to-metal interfaces
• Thermostats and bimetals
• Precision electronic components
• Aerospace instrumentation

📈 Key Advantages

• ✅ Ultra-low and stable coefficient of thermal expansion (CTE)
• ✅ Excellent hermetic sealing capability
• ✅ High dimensional stability across temperature cycles
• ✅ Suitable for high-vacuum and high-reliability environments
• ✅ Matches thermal expansion of glass/ceramic materials (e.g., borosilicate)

🧪 Chemical Composition (typical for Alloy 27 / UNS K92801)

🧩 Mechanical and Physical Properties

• Coefficient of Thermal Expansion (CTE): ~5.2–5.8 × 10⁻⁶ /°C (20–300 °C)
• Tensile Strength: ~480–650 MPa
• Yield Strength: ~275–400 MPa
• Elongation: ≥ 25%
• Hardness: ~150–200 HV
• Density: ~8.2 g/cm³
• Electrical Resistivity: ~0.5–0.6 μΩ·m

✅ Conclusion

Alloy 27 / UNS K92801 is a high-performance controlled expansion alloy engineered for environments where thermal precision and hermeticity are critical. It is the ideal choice for advanced electronic packaging, aerospace instrumentation, and high-reliability sealing systems.

Delivery Forms Alloy 27