Manufacturing High Precision Parts Kovar 4J29 Rod 29% Nickel 17% Cobalt

Product Introduction

Kovar 4J29 rod is a kind of iron nickel cobalt alloy bar with low coefficient of thermal expansion, which is widely used in electronic packaging, aerospace, precision instruments and other fields. Its main components include about 29% nickel, 17% cobalt and residual iron, as well as trace elements such as silicon and manganese.  Kovar 4J29 rod has good machinability, good machinability and formability. Common processing methods include turning, milling, drilling, etc. In addition, it also has good welding performance, usually using laser welding, electron beam welding or brazing and other high energy density welding methods. These characteristics make Kovar 4J29 rod an ideal material for manufacturing parts with high precision and high strength requirements, especially in applications requiring sealed connection with glass or ceramics.

Heat treatment system:

This alloy has a linear expansion coefficient of about 4.6 × 10 ⁻⁶/℃ similar to that of borosilicate hard glass in the temperature range of 20 ℃ to 450 ℃, with a high Curie point and good low-temperature microstructure stability. Kovar 4J29 rod has a density of 8.36 g/cm ³, a resistivity of 0.49 μ Ω· m, and a thermal conductivity of 17 w/(m · K). It has a high permeability at room temperature. After specific heat treatment, its hysteresis loss can be significantly reduced. Its mechanical properties show good strength and toughness, the tensile strength is usually 450-550 MPa, the elongation is 30% -40%, and the hardness is between hb140-180.

The performance test samples for the expansion coefficient and low-temperature tissue stability specified by the standard are heated to 900 ℃± 20 ℃ in a hydrogen atmosphere, held for 1 hour, then heated to 1100 ℃± 20 ℃, held for 15 minutes, and cooled to below 200 ℃ at a rate not exceeding 5 ℃/min before being taken out of the furnace.

Parameter

Specific Applications

1. Electronic packaging: Kovar 4J29 rod is widely used in the field of electronic packaging, especially in the connecting parts with glass and ceramic packaging materials, which can effectively reduce the stress problems caused by thermal expansion mismatch.
2. Vacuum electronic devices: in the application of vacuum electronic devices, Kovar 4J29 rod is often used as packaging material due to its high corrosion resistance and high temperature performance to ensure the long-term stability and reliability of the device.
3. Optical devices and precision instruments: in optical instruments and precision measuring equipment, Kovar 4J29 rod can ensure the dimensional stability of the device under different temperature conditions due to its stable thermal expansion characteristics, especially in precision structural parts, to avoid the deformation caused by temperature changes.

Advantages and Characteristics

• Good mechanical properties: Kovar 4J29 rod has high strength and good ductility. Its tensile strength is usually 450-550 MPa, elongation is 30%-40%, and hardness is between hb140-180. This strength and toughness enable it to adapt to a variety of processing methods, especially in electronic packaging and precision instrument manufacturing.
• Excellent electrical performance: the resistivity of Kovar 4J29 rod is low, usually about 10% of that of copper, which makes it suitable for high-precision electronic equipment, especially in the environment requiring low conductivity but with good stability.
• Good machinability: Kovar 4J29 rod has good machinability and formability. Common processing methods include turning, milling, drilling, etc., and it can maintain high dimensional stability in these processing processes. For the production of precision parts, especially in the field with strict requirements for thermal expansion characteristics, precision machining can ensure the high precision and reliability of components.

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Q&A

1. how hard is Kovar 4J29?
The hardness of Kovar 4J29 is generally about HRC 30-35, which can be further adjusted after appropriate heat treatment.

2. how about the mechanical properties of Kovar 4J29?
The tensile strength of Kovar 4J29 is about 800 MPa, the yield strength is about 500 MPa, and the elongation is 20% -25%.

3. how about the corrosion resistance of Kovar 4J29?
Kovar 4J29 has good corrosion resistance, especially in atmospheric environment and weak acid environment.

4. how about the magnetic properties of Kovar 4J29?
Kovar 4J29 has ferromagnetism below the Curie point (about 435 ℃), and loses ferromagnetism beyond the Curie point.