4J29 Kovar Alloy Sheet for Glass-to-Metal Sealing ASTM F15
| Attribute | Value |
|---|---|
| Model NO. | Expansion Alloy |
| Transport Package | DIN Spool, Carton, Wooden Case |
| HS Code | 7505220000 |
| Purity | Alloy |
| Production Capacity | 1500tons/Year |
| Origin | Jiangsu, China |
| Coefficient of Expansion | 5.0 × 10⁻⁶ /°C (30–400°C~) |
| Surface Finish | Bright, Cold-Rolled, Ground, or Annealed Matte |
4J29 alloy sheet, also known internationally as Kovar alloy (UNS K94610, ASTM F15), is a nickel-iron-cobalt alloy with controlled thermal expansion characteristics. It is widely used in hermetic sealing applications due to its precisely matched coefficient of expansion with hard glass and ceramics.
The alloy maintains dimensional stability across a wide temperature range, making it ideal for use in electronic components requiring tight tolerances and vacuum integrity. Typical applications include glass-to-metal seals in transistors, vacuum tubes, integrated circuits, microwave packages, and optical housings.
Available in cold-rolled or annealed condition, 4J29 sheets offer excellent workability, uniform grain structure, and high surface finish for precision forming and sealing processes.
- Matched thermal expansion with borosilicate and aluminosilicate glasses
- Excellent hermeticity and vacuum sealing performance
- Stable mechanical properties across temperature ranges
- Easily machined, deep drawn, or stamped
- Good oxidation resistance in air
- Compliant with ASTM F15 and GB/T 14986 standards
- Hermetic glass-to-metal seals
- Electronic packaging (IC, transistor, diode headers)
- Microwave devices and optical components
- Relay housings, vacuum tubes, and sensor shells
- Aerospace and communication electronics
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 29.0 ± 1.0 |
| Cobalt (Co) | 17.0 ± 1.0 |
| Iron (Fe) | Balance |
| Silicon (Si) | ≤ 0.3 |
| Manganese (Mn) | ≤ 0.5 |
| Carbon (C) | ≤ 0.05 |
| Chromium (Cr) | ≤ 0.2 |
| Phosphorus (P) | ≤ 0.015 |
| Sulfur (S) | ≤ 0.015 |
| Aluminum (Al) | ≤ 0.1 |
| Copper (Cu) | ≤ 0.2 |
| Property | Typical Value |
|---|---|
| Tensile Strength | ≥ 450 MPa |
| Yield Strength | ≥ 300 MPa |
| Elongation (L=50 mm) | ≥ 20% |
| Hardness (HV) | ≤ 200 HV |
| Density | 8.3 g/cm³ |
| Coefficient of Expansion | 5.0 × 10⁻⁶ /°C (30-400°C~) |
| Melting Range | 1450 - 1500°C |
| Electrical Resistivity | ~0.42 μΩ*m |
| Item | Details |
|---|---|
| Thickness Range | 0.05 mm - 5.0 mm (custom sizes available) |
| Width | Up to 600 mm (slit widths available) |
| Length | Up to 3000 mm (or coils upon request) |
| Surface Finish | Bright, Cold-Rolled, Ground, or Annealed Matte |
| Tolerance | Thickness: ±0.01 mm; Width: ±0.5 mm (custom precision available) |
| Delivery Condition | Annealed / Stress Relieved / Pickled |
| Packaging | Vacuum sealed + export wooden case; rust-preventive wrap included |
| Certification | ISO 9001 / Material Certificate (EN 10204 3.1/3.2) / RoHS / REACH |
| Country of Origin | China (OEM support available) |
- Custom stamping or laser cutting
- Surface cleaning for vacuum applications
- Pre-punched or slotted formats
- Cleanroom packaging
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