Alloy 46 is a nickel-iron controlled-expansion alloy with a nominal 46% nickel content, balance iron. It is engineered specifically for high-integrity glass-to-metal and ceramic-to-metal sealing applications where thermal expansion matching is critical to long-term reliability.

1. Operating Limits & Selection Criteria

This alloy is selected primarily for its predictable expansion behavior rather than strength or corrosion resistance. Its key specification boundary is thermal stability range.

• Effective Temperature Range: Maintains controlled, stable coefficient of thermal expansion from room temperature up to 500°C (932°F) .

• Material Matching: Formulated to match the expansion curves of specific hard glasses and alumina ceramics used in hermetic device manufacturing.

• Performance Requirement: By matching contraction rates during cooling from sealing temperatures, Alloy 46 prevents residual stress that leads to cracks, leaks, or vacuum loss in sealed assemblies.

• Note on Higher Temperatures: For applications requiring expansion control beyond 500°C, alternative alloys with higher nickel content should be evaluated.

2. Manufacturing Data & Specifications

• Chemical Composition (Typical)

  Element	Content (%)
  Nickel (Ni)	46.0
  Carbon (C)	0.05 max
  Silicon (Si)	0.30 max
  Chromium (Cr)	0.025 max
  Sulfur (S)	0.025 max
  Iron (Fe)	Balance

• Physical Properties

  Property	Metric	Imperial
  Density	8.165 g/cm³	0.295 lb/in³
  Melting Point	1427°C	2600°F

• Mechanical Properties (Typical, Annealed)

  Property	Metric	Imperial
  Tensile Strength	552 MPa	80 ksi
  Yield Strength	242 MPa	35 ksi
  Elongation at Break	30%	30%

• Fabrication Considerations

  • Annealing: Required to achieve proper softness and controlled expansion characteristics. Typically performed at 800-1000°C in a protective atmosphere to prevent oxidation.

  • Surface Condition: For reliable glass sealing, surfaces must be clean, free of contaminants, and properly prepared to ensure glass wetting.

  • Cold Working: Not recommended for finished components without subsequent annealing, as residual stresses will distort the CTE and may cause seal failure.

3. Applications

Alloy 46 is specified wherever a hermetic seal must survive thermal cycling while maintaining vacuum or pressure integrity:

• Glass-to-metal seals (GTMS) in electronic tubes and vacuum devices

• Ceramic-to-metal seals (CTMS) in high-reliability assemblies

• Aerospace and defense: Radar systems, traveling wave tubes, avionics

• Telecommunications: High-frequency vacuum tubes

• Medical electronics: Sensors and imaging equipment requiring hermetic protection

• Automotive: High-reliability sensors for electric and autonomous vehicle systems

4. Available Product Forms & Supply

For engineers and procurement specialists requiring controlled-expansion alloys for hermetic sealing applications, ZYTC Alloy stocks certified Alloy 46 (1J46 / UNS K94600) in standard mill forms:

• Sheet

• Strip (precision slit for stamping)

• Plate

All material is supplied with full traceability and certification, suitable for mission-critical defense, medical, and industrial applications. Contact ZYTC Alloy for stock availability and pricing.

Contact Us:

Email:daisy@zytcsteel.com

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