Iron Nickel Cobalt Alloy Wire 4J29 Kovar Wire Precision Alloy Wire With Good Weldability

Product Introduction

Kovar 4J29 wire is a kind of iron nickel cobalt alloy wire with low thermal expansion coefficient, 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. The thermal expansion coefficient of this alloy matches that of borosilicate glass and alumina ceramics, and it is particularly suitable for glass to metal sealing applications, such as high-power transmission valves, transistor pins and bases, integrated circuit lead frames, and photographic flash bulbs. Kovar 4J29 wire shows good comprehensive mechanical properties in high temperature environment, especially under proper temperature control, with excellent heat resistance and fatigue resistance. In addition, it also has good welding performance and corrosion resistance, and can be welded with other metals and alloys to realize the connection and assembly of components. These characteristics make Kovar 4J29 wire an ideal material for manufacturing parts with high precision and high strength requirements.

Heat treatment system:

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 wire 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 wire is often used as packaging material due to its high corrosion resistance and high temperature performance, ensuring the long-term stability and reliability of the device.
3. Optical devices and precision instruments: in optical instruments and precision measuring equipment, Kovar 4J29 wire, due to its stable thermal expansion characteristics, can ensure the dimensional stability of the device under different temperature conditions, especially in precision structural parts, to avoid the deformation caused by temperature changes.

Advantages and Characteristics

• Low thermal expansion coefficient: the thermal expansion coefficient of Kovar 4J29 wire in the temperature range of 20 ℃ to 450 ℃ is approximately 5.1 × 10 ⁻⁶/° C, which matches well with the thermal expansion coefficient of glass and ceramics, which makes it able to effectively avoid structural stress caused by thermal expansion mismatch in high-precision assembly.
• Good mechanical properties: Kovar 4J29 wire 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 wire 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 wire 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.

Processing performance:

1. Melting and Casting: Electric arc furnaces or induction furnaces are usually used for melting, and suitable mold materials and cooling rates are required during the casting process to ensure the uniformity and density of the alloy.
2. Heat treatment and annealing: Reasonable heat treatment can significantly improve the ductility and processability of 4J29 alloy, providing favorable conditions for subsequent cold or mechanical processing. The annealing temperature is usually between 850 ℃ and 950 ℃.
3. Machinability: It has good cutting and formability, and common machining methods include turning, milling, drilling, etc. It can maintain high dimensional stability during these machining processes.
4. Welding performance: High energy density welding methods such as laser welding, electron beam welding, or brazing are usually used to ensure the strength and sealing of the joint. During the welding process, it is necessary to strictly control the temperature gradient and cooling rate to prevent cracks or other defects in the welding area.

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Q&A

What are the main application areas of Kovar 4J29?
Kovar 4J29 is widely used in electronic component packaging, aerospace, medical devices, optical fields, etc.

How about the processing performance of Kovar 4J29?
Kovar 4J29 has good processing performance and can be processed by conventional metal processing technologies such as forging, rolling and stretching.

What is the welding performance of Kovar 4J29?
Kovar 4J29 has good welding performance and can meet the requirements of various butt welding, shielded gas arc welding and resistance welding.

What is the heat treatment process of Kovar 4J29?
The heat treatment process of Kovar 4J29 includes solid solution treatment (1000 ° c-1100 ° C, water quenching or oil quenching), aging treatment (700 ° c-800 ° C, holding for 2-3 hours) and annealing treatment (800 ° c-1000 ° C, air cooling).

What is the density and melting point of Kovar 4J29?
Kovar 4J29 has a density of about 8.36 g/cm ³ and a melting point of about 1449 ℃.
Mainly used in aerospace, electronic packaging, vacuum electronic devices, and optical instruments.