Alloy 45 is a nickel-iron controlled-expansion alloy (approximately 46% nickel) engineered specifically for high-temperature hermetic sealing applications. Its primary advantage is maintaining a consistently low coefficient of thermal expansion up to 538°C (800°F), making it suitable for environments where standard sealing alloys would experience dimensional instability.

1. Operating Limits & Selection Criteria

Unlike standard glass-sealing alloys that lose expansion control at moderate temperatures, Alloy 45 is specified when service conditions exceed 300°C.

• Effective Temperature Range: Maintains controlled expansion characteristics up to 538°C (800°F) , surpassing Alloy 42 and similar materials.

• Sealing Mechanism: Designed specifically for compression seals. The alloy's CTE is slightly higher than the mating ceramic or glass, creating a compressive grip upon cooling that ensures mechanical integrity.

• Material Matching: Compatible with specific hard glasses and alumina ceramics used in high-power and vacuum applications.

2. Manufacturing Data & Processing Requirements

• Chemical Composition (Typical)

  Element	Weight %
  Nickel (Ni)	46.0
  Iron (Fe)	Balance
  Manganese (Mn)	0.80 max
  Silicon (Si)	0.30 max
  Carbon (C)	0.05 max
  Chromium (Cr)	0.10 max
  Aluminum (Al)	0.10 max
  Magnesium (Mg)	0.50 max
  Phosphorus (P)	0.025 max
  Sulfur (S)	0.025 max

• Mechanical Properties (Typical, Annealed)
  (Note: Exact values depend on temper; typical ranges shown)

  Property	Metric	Imperial
  Tensile Strength	480 - 550 MPa	70 - 80 ksi
  Yield Strength	240 - 300 MPa	35 - 43 ksi
  Elongation	25 - 35%	25 - 35%

• Physical Properties

  Property	Metric	Imperial
  Density	Approx. 8.2 g/cm³	0.296 lb/in³
  Curie Point	~370°C	~700°F

• Fabrication Considerations

  • Annealing: Required to achieve proper expansion characteristics. Perform at 800-1000°C in protective atmosphere.

  • Brazing Compatibility: Alloy 45 accepts standard brazing techniques used in eyelet and compression seal assemblies.

  • Surface Preparation: For reliable glass-to-metal sealing, surfaces must be clean and oxide-free prior to sealing.

3. Applications

Alloy 45 is specified where hermetic integrity must survive thermal cycling in demanding environments:

• High-power electron tubes (aerospace, defense, broadcast)

• Hermetic feedthroughs for vacuum furnaces and process equipment

• Compression seals and eyelet brazed assemblies

• Automotive and aerospace sensors exposed to engine heat

• High-reliability hermetic connectors

4. Available Product Forms & Supply

For engineers and procurement specialists requiring controlled-expansion alloys for high-temperature seals, ZYTC Alloy supplies certified Alloy 45 in forms suitable for stamping, forming, and direct sealing:

• Sheet

• Strip (precision slit for stamping)

• Plate

Material is supplied with full traceability and certification, suitable for mission-critical defense, aerospace, and industrial applications.

Contact Us:

Email:daisy@zytcsteel.com

WhatsApp/WeChat: +86 17335753350