• Huona (Shanghai) New Material Co., Ltd.
    Alfred***
    We received the goods, everything went fine. Perfect packaging, good product quality, good price - we are satisfied.
  • Huona (Shanghai) New Material Co., Ltd.
    May***
    The product quality is very good, beyond my expectations, the actual use of fully meet my needs, we will buy again.
  • Huona (Shanghai) New Material Co., Ltd.
    Matthew***
    I bought low expansion alloy from Joy, She is a very responsible lady, Tankii's products quality is pretty good.
Contact Person : Joy
Phone Number : +86 18930254719
WhatsAPP : 8618930254719

4j29 Ni29co17 Kovar WIRE Precision Alloy Invar36 4j42 Iron Nickel Constant Expansion WIRE

Place of Origin CHINA
Brand Name HUONA
Certification ISO9001
Model Number WIRE
Minimum Order Quantity 1KG
Price US$12.00-45.00
Packaging Details 1500tons/Year
Delivery Time WEEK
Payment Terms T/T
Supply Ability 1000kg Per Week

Contact me for free samples and coupons.

WhatsAPP:0086 18588475571

Wechat: 0086 18588475571

Skype: sales10@aixton.com

If you have any concern, we provide 24-hour online help.

x
Product Details
Model NO. Expansion Alloy HS Code 7505220000
Purity Alloy Specification Customized
Origin Jiangsu, China Production Capacity 1500tons/Year
Highlight

4j29 Low Expansion Alloy

,

4j29 iron nickel wire

,

ISO9001 Low Expansion Alloy

Leave a Message
Product Description
Kovar Alloy Wire Material 4j29 Ni29co17 Kovar WIRE Precision Alloy Invar36 Nilo42 4j42 Iron Nickel Constant Expansion WIRE

Product Description

Product Introduction – 4J29 Alloy Wire Rod (Kovar Equivalent)

4J29, also known as Kovar in international standards, is a Nickel–Iron–Cobalt controlled expansion alloy engineered for glass-to-metal and ceramic-to-metal sealing. Its thermal expansion closely matches that of hard glass and alumina ceramics, making it an ideal material for hermetic packaging, vacuum electronics, and aerospace components.

As a wire rod, 4J29 is supplied in spooled wire, straight rods, or custom-cut lengths, with tight dimensional tolerances and excellent surface finish.

Technical Specifications:

Property Value
Alloy Name 4J29 (Equivalent to Kovar)
Chemical Composition Ni: ~29%, Co: ~17%, Fe: Balance
CTE (30–300°C) ~5.0 × 10⁻⁶ /°C
Density ~8.3 g/cm³
Tensile Strength 450–750 MPa (annealed)
Yield Strength ≥ 300 MPa
Elongation ≥ 25%
Electrical Resistivity ~0.42 μΩ·m
Thermal Conductivity ~17 W/m·K
Melting Range ~1450–1500°C
Wire Rod Diameter Range 0.1 mm – 6.0 mm (custom sizes available)
Condition Annealed / Bright / Oxidized / Pickled
Packaging Coils, straight rods, spool, or custom-cut
Industry Application Examples
Electronics Transistor cans, relay headers, integrated circuit housings
Optoelectronics TO headers, photodiode cases, laser housings
Aerospace Hermetic sensors, thermal control components
Vacuum Electronics Tube components, getter assemblies
Medical Devices Sealed implantable components, bio-safe hermetic packaging
Telecom Fiber optic connectors, microwave & RF sealing elements
Defense Hermetically sealed sensors and modules

Product Overview – 4J42 Alloy (Low Expansion Alloy)

4J42 is a Nickel-Iron alloy designed to have a low coefficient of thermal expansion (CTE). It is primarily used in applications that require precise dimensional stability across temperature variations, making it ideal for glass-to-metal sealing, ceramic-to-metal sealing, and high-precision electronic components.

This alloy is typically used in industries such as aerospace, electronics, and telecommunications, where the thermal expansion properties of materials are critical to maintaining the functionality and reliability of components.

 

Precision alloys are metal materials with special physical properties (such as magnetic, electrical, thermal and other properties). The vast majority of precision alloys are based on ferrous metals, and only a few are based on non-ferrous metals. Usually include magnetic alloys (see magnetic materials), elastic alloys, expansion alloys, thermal bimetals, electrical alloys, hydrogen storage alloys (see hydrogen storage materials), shape memory alloys, magnetostrictive alloys (see magnetostrictive materials), etc. 

 

Industry Application Examples
Electronics Glass-to-metal seals for vacuum tubes, transistor cans, semiconductor housings
Aerospace Seals for sensors, connectors, and components in aerospace systems
Telecommunications Microwave and RF components, fiber optic connectors, satellite components
Medical Devices Hermetic sealing for implantable devices and bio-compatible sensors
Automotive Automotive electronic sensor housings, connectors, and precision seals
Vacuum Systems Vacuum tube components, electrical contacts
Property Value
Alloy Name 4J42 (Nickel-Iron Alloy)
Chemical Composition Ni: ~42%, Fe: Balance
CTE (20–100°C) ~4.7 × 10⁻⁶ /°C
Density ~8.2 g/cm³
Tensile Strength 450–700 MPa (annealed)
Yield Strength ≥ 300 MPa
Elongation ≥ 20%
Hardness ~160 HV (annealed)
Electrical Resistivity ~0.48 μΩ·m
Magnetic Properties Magnetic at room temperature
Melting Range ~1450°C
Wire Diameter Range 0.10 mm – 6.0 mm (custom sizes available)
Surface Finish Bright / Annealed / Oxidized
Packaging Spools, coils, or custom lengths

 

Product Parameters

Soft magnetic alloys are a class of alloys with high permeability and low coercivity in weak magnetic fields. According to the different elements that make up the alloy, it can be divided into electromagnetic pure iron (industrial pure iron), iron-silicon alloy, iron-nickel alloy, iron-aluminum alloy, iron-silicon-aluminum alloy and iron-cobalt alloy, etc.1J06,1J12,1J17,1J18,1J22,1J30,1J36,1J38,1J46,1J50,1J51,1J54,1J76,1J77,1J79,1J80,1J85,1J87

Permanent magnet alloy not only has high hardness and mechanical properties, but also has strong anti-demagnetization ability, high coercivity value (greater than 20kA/m), magnetic "hard" and other characteristics, so it is also called hard magnetic alloy.2J04,2J07,2J09,2J10,2J31,2J53,2J84,2J85Elastic alloys include high elastic alloys and constant elastic alloys. It is used to make elastic elements such as elastic sensitive elements, energy storage elements and frequency elements in precision instruments.3J01,3J21,3J53Expansion alloys(Invar Alloy) are divided into Kovar alloys, ceramic sealing alloys, low expansion alloys, and constant expansion alloys. Widely used in electronic industry, precision measuring tools, precision instruments and low temperature engineering and other fields.4J28,4J29,4J32,4J33,4J36,4J40,4J42,4J50
Precision alloys with nickel, chromium, aluminum and iron as the main components, the resistivity is about three times higher than that of manganese copper, and has a lower temperature coefficient of resistance and low thermal potential to copper, with good long-term resistance stability and resistance. Oxidation properties.
It is suitable for making precision resistance elements in various measuring instruments and meters, making precision micro-resistance elements and strain