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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36

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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Kovar Capillary Tube (4J29) / K94610
Alloy 46 / 1J46 / Fe-46Ni / UNS K94600
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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Nimonic 80A / UNS N07080 / W. Nr 2.4952
Nimonic 263 / UNS N07263 / W.Nr: 2.4650 / Age-Hardenable Nickel-Cobalt-Chromium-Molyb- Denum Alloy 263 / Haynes C263
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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Waspaloy alloy bar N07001/GH4738/ Waspaloy Strip/Wasaploy pipe
MP35N Bar/ AMS5844 / High Tensile Strength Cobalt Alloy MP35N / R30035 Wire/
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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Inconel 718 / Nickel Alloy 718 / UNS: N07718 / W. Nr: 2.4668/NiCr19Fe19Nb5Mo3 / NA 51 / NC19FeNb
InconelX-750 / N07750 / W.Nr.2.4669 / NiCr15Fe7TiAl / NC15TNbA / GH4145
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Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36
Alloy L605 / Haynes 25 / UNS R30605 / W.Nr 2.4964 / Cobalt L605 / GH5605
Incoloy A-286 / UNS S66286 / W.Nr 1.4980
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Short Description:

Invar 36 is a nickel-iron, low expansion alloy that contains 36% nickel and possesses a rate of thermal expansion approximately one-tenth that of carbon steel. Alloy 36 maintains nearly constant dimensions over the range of normal atmospheric temperatures, and has a low coefficient of expansion from cryogenic temperatures to about 500°F. This nickel iron alloy is tough, versatile and retains good strength at cryogenic temperatures.

Product Description

Invar 36 is a special iron nickel alloy with ultra-low expansion coefficient. The control of carbon and manganese components is very important. It has a stable low expansion coefficient in a specific temperature range. Invar 36 is resistant to corrosion in dry air at room temperature. Corrosion (rust) occurs in other harsh environments, such as humid air.Invar 36 can be hot and cold formed and machined using processes similar to austenitic stainless steels.


FeNi50, also known as Alloy 50 or Permalloy, is a soft magnetic alloy primarily composed of iron (Fe) and nickel (Ni). It is characterized by its high magnetic permeability and low coercivity, making it ideal for applications in magnetic cores, transformers, inductors, and magnetic shielding.

The composition of FeNi50 typically consists of approximately 50% nickel and 50% iron, with small amounts of other elements such as manganese (Mn) and copper (Cu). The specific composition may vary slightly depending on the manufacturer or specific grade of the alloy.

FeNi50 exhibits the following key properties:

  1. High magnetic permeability: FeNi50 has a high initial permeability, which means it can easily attract and conduct magnetic fields. This property makes it suitable for applications where high magnetic flux density or low-core loss is required.

  2. Low coercivity: Coercivity refers to the resistance of a material to changes in its magnetization. FeNi50 has a low coercive force, making it easily magnetized and demagnetized, which is advantageous for applications requiring frequent magnetization and demagnetization cycles.

  3. Low hysteresis loss: Hysteresis loss is the energy lost when a magnetic material undergoes a complete magnetization and demagnetization cycle. FeNi50 has low hysteresis loss, contributing to its efficiency in magnetic applications.

  4. Excellent magnetic shielding: FeNi50 demonstrates high magnetic permeability combined with low coercivity, making it effective in shielding against external magnetic fields and reducing electromagnetic interference (EMI) in sensitive electronic devices.

Composition and Elements

FeNi50 is formulated by meticulously combining iron and nickel in specific proportions. Iron contributes structural stability and mechanical strength, while nickel enhances properties such as corrosion resistance, thermal conductivity, and magnetic behavior. The 50% nickel composition in FeNi50 defines its characteristics, providing a balanced amalgamation of both elements’ attributes.

Mechanical Properties

The theoretical FeNi50 alloy is engineered to display impressive mechanical properties. With its combination of iron and nickel, it might exhibit high tensile strength, excellent ductility, and good toughness. These mechanical attributes could render it suitable for applications requiring robust materials capable of withstanding mechanical stress and deformation.

Corrosion Resistance

One of the potentially defining features of FeNi50 is its resistance to corrosion. Nickel, known for its corrosion-resistant properties, especially in acidic or caustic environments, could impart similar qualities to FeNi50. This corrosion resistance might make it suitable for applications in chemical processing, marine environments, or areas prone to rust and degradation.

Thermal and Magnetic Properties

FeNi50 could potentially possess favorable thermal conductivity and expansion characteristics due to the combination of iron and nickel. Furthermore, with nickel’s inherent magnetism, this alloy might exhibit magnetic properties, which could be advantageous in certain specialized applications where magnetic properties are desirable.


While the FeNi50 alloy is theoretical, its hypothetical properties suggest potential applications across several industries:

  1. Electronics and Electrical Engineering: FeNi50 might find utility in electronics or electrical components requiring materials with specific thermal and magnetic properties, such as sensors, actuators, or magnetic shielding.

  2. Chemical Processing: Its corrosion resistance could make FeNi50 suitable for use in chemical processing equipment, reactors, or pipelines exposed to corrosive substances.

  3. Aerospace and Automotive: The alloy’s mechanical strength and resistance to corrosion could potentially find application in components requiring durability, such as aircraft parts, automotive exhaust systems, or structural elements.

  4. Medical Equipment: FeNi50’s theoretical properties might make it applicable in medical devices where resistance to corrosion and biocompatibility are essential factors.

Due to its unique magnetic properties, FeNi50 is widely used in industries such as telecommunications, electronics, power generation, and aerospace. It is utilized in components such as transformer cores, magnetic shielding, magnetic sensors, magnetic amplifiers, and magnetic recording devices.

Invar 36 Characteristic:

Invar 36 can be hot and cold formed and machined using processes like austenitic stainless steels and is also weldable using Filler Metal CF26. Some of the other benefits associated with the use of Invar nickel alloy 36 include: 

  • Superior dimensional stability
  • Numerous workability aspects
  • Extremely low coefficient of thermal expansion (CTE)

Invar 36 Chemical Composition

Weight % Ni Fe C Mn P S Si Cr Mo Co
Invar 36 35-38 Rem ≤0.10 ≤0.06 ≤0.025 ≤0.025 ≤0.35 ≤0.50 ≤0.50 ≤1.0

Invar 36 Physical Properties

Density Melting range
8.1 g/cm³ 1430-1450°C

Invar 36 Mechanical Properties

Condition Melting range Yield Strength 0.2 % Elongation (%)
- psi MPa psi MPa -
Annealed 71000 490 35000 240 42
  • Bars & Rods & Foring Ring /Flanges
  • Sheet & Plate
  • Strip & Coil
  • Welding Wire &Spring wire
  • Seamless Tube & Welded Pipe

»Round Bar & Square Bar & Hexagon Bar       

● Diameter : φ8~φ300mm   Length:10mm-6000mm

● Hot forging, Hot Rolling, Cold Drawing

● Bright Surface, Polished Surface, Black Surface

»Tube & Pipe:Seamless Tube& Welded Pipe

● Cold Drawing Seamless Pipe: φ1.0~φ220mm

● Hot Extrusion pipe: φ50~φ250mm

● Others : U Blend Tube and Elbow

»Hot Rolled Plate & Cold Rolled Sheet 

● Cold Rolling Sheet Thickness: ≦2.0mm      Width:≦1500m

● Hot rolling Plate Thickness: ≧4.0mm         Width: ≦2500m

»Strip & Tape Ribbon

● Thickness: ≧ 0.01mm     Width: 15mm-300mm

● Cold rolling BA Strip, Hard & Soft Condition

»Straight Length Wire & Spool Wire 

● Welding Wire: φ 0.1mm~6.0mm      Cut length Rod: φ1.0~φ8.0mm

● Package : 5-25kg/Spool or Box

Invar 36 (4J36) / K93600 / W. Nr: 1.3912 / Low Expansion Alloy Nilo36 / Pernifer 36 / FeNi36

Invar 36 ApplicationsI

● Production, storage and transportation of liquefied gas

● Working temperature below +200℃ measurement and control instruments, Such as temperature adjustment device

● metal and other materials between the helix connector bushings

● bimetal and temperature control bimetal

● film frame

● shadow mask

● aviation industry CRP parts tempering mold

● less than -200℃ satellite and missile electronic control unit frame

● laser control device electromagnetic lens in the auxiliary electron tube

FeNi36, also known as Invar 36, is a unique iron-nickel alloy renowned for its low coefficient of thermal expansion (CTE). Developed in the early 20th century, this alloy has found widespread use in precision engineering applications where dimensional stability is critical. FeNi36’s remarkable property of near-zero thermal expansion over a wide temperature range makes it a preferred choice for applications requiring precise dimensional control and stability.

Key Features:

  1. Low Thermal Expansion: FeNi36 exhibits an exceptionally low coefficient of thermal expansion, approaching zero over a wide temperature range. This characteristic enables components made from FeNi36 to maintain their shape and dimensions, even under extreme temperature fluctuations.

  2. Dimensional Stability: The low CTE of FeNi36 provides excellent dimensional stability, making it ideal for applications requiring tight tolerances and minimal thermal distortion.

  3. High Mechanical Strength: FeNi36 possesses good mechanical strength and can withstand mechanical stresses without compromising its dimensional stability.

  4. Corrosion Resistance: The alloy offers moderate corrosion resistance in various environments, further enhancing its suitability for demanding applications.


FeNi36 (Invar 36) is used in a wide range of precision engineering applications, including but not limited to:

  1. Aerospace and Satellite Technology: FeNi36 is employed in aerospace components, satellite structures, and scientific instruments where dimensional stability is crucial to maintain precise performance under varying temperature conditions.

  2. Electronic and Electrical Industry: Invar 36 is utilized in electronic and electrical components such as thermostats, relay parts, and precision coils, ensuring accurate responses to temperature changes.

  3. Optical Instruments: FeNi36 is an essential material in optical devices, telescopes, and camera shutters, where stable dimensions are vital for maintaining optical alignment.

  4. Metrology and Calibration Standards: Invar 36 is used in the creation of calibration standards and measuring instruments, providing consistency and accuracy in dimensional measurements.

  5. Cryogenic Engineering: FeNi36 is employed in cryogenic systems, superconducting devices, and liquid gas storage tanks due to its low thermal expansion properties at extremely low temperatures.

  6. Seismic Instruments: Invar 36 is utilized in seismometers and geophysical equipment, where stability and accuracy are essential for measuring seismic activity.

Product Forms: 

FeNi36 (Invar 36) is available in various forms, including:

  • Sheet and Plate: FeNi36 sheet and plate are used in the fabrication of precision components with stable dimensions.

  • Wire: FeNi36 wire is utilized in electrical and electronic applications, as well as in thermally compensated components.

  • Rod and Bar: FeNi36 rods and bars find use in precision engineering and specialized applications that demand high mechanical stability.

  • Tubes and Pipes: Invar 36 tubes and pipes are used in cryogenic and thermal applications, where dimensional stability is crucial.


FeNi36 (Invar 36) is an exceptional iron-nickel alloy with near-zero thermal expansion properties, offering outstanding dimensional stability over a wide temperature range. Its unique characteristics make it an indispensable material in precision engineering applications, where dimensional accuracy and stability are critical. From aerospace and electronics to cryogenic systems and seismic instruments, FeNi36 plays a vital role in maintaining precision and reliability in a diverse array of cutting-edge technologies. As a go-to material for demanding applications, FeNi36 (Invar 36) continues to be a fundamental enabler of technological advancement and innovation in various industries.

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