4J33 Glass-Sealing Alloy Specification
Fe-Ni-Co Alloy for Precision Glass-to-Metal Sealing Applications
Product Specification
| Standard | GB/T 15018 (China), ASTM F15 (USA) |
| Material Designation | 4J33 (Fe-Ni-Co), Ni33Co14 |
| Tolerance | h7-h11 (on request) |
| Melt Method | Vacuum Induction Melting (VIM) |
| Available Forms & Sizes | Strip: 0.05-3.0mm thick (≤300mm width) Wire: φ0.10mm – φ5.0mm Bar: 3-100mm diameter Custom profiles upon request |
Chemical Composition (wt%)
| Element | Min | Max |
| Nickel (Ni) | 32.5 | 33.5 |
| Cobalt (Co) | 13.5 | 14.5 |
| Iron (Fe) | Balance | |
| Manganese (Mn) | – | 0.50 |
| Silicon (Si) | – | 0.30 |
| Carbon (C) | – | 0.05 |
| Copper (Cu) | 0.10 | 0.25 |
| Phosphorus (P) | – | 0.02 |
| Sulfur (S) | – | 0.02 |
Thermal & Physical Properties
| Property | Value | Test Condition |
| Average CTE (20-300°C) | 5.1-5.7 ×10⁻⁶/°C | Annealed condition |
| Average CTE (20-400°C) | 6.3-7.1 ×10⁻⁶/°C | Annealed condition |
| Density | 8.1 g/cm³ | Room temperature |
| Melting Point | 1420-1450°C | |
| Curie Temperature | 350-380°C | |
| Thermal Conductivity | 16.5 W/(m·K) | 20°C |
| Electrical Resistivity | 0.48 μΩ·m | 20°C |
Mechanical Properties
- Tensile Strength: 500-580 MPa
- Yield Strength (0.2%): 350-420 MPa
- Elongation: ≥30%
- Hardness: 140-180 HV
- Modulus of Elasticity: 145 GPa
- Fatigue Strength: 220-280 MPa
- Poisson’s Ratio: 0.30
- Magnetic Permeability: 1.003-1.005
Applications
- Aerospace electronic housings and connectors
- Semiconductor packaging and chip carriers
- High-power lamp bases and vacuum tube leads
- Laboratory instrument seals and connectors
- Medical device hermetic seals
- Power electronic module housings
Special Processing Notes
- Recommended heat treatment: 850°C±10°C water quench for optimal CTE
- Hydrogen firing at 950-1050°C for 15-30 minutes required for glass sealing applications
- Avoid nickel plating before glass sealing operations
- Store in dry, controlled environment (≤40% RH) to prevent surface oxidation
