Corrosion resistant 4j36 capillary tube Invar alloy 4j36 thin wall round tube size can be customized.‌

4J36 alloy has a density of 8.1g/cm³‌. ‌

4J36 is an iron-nickel alloy with an ultra-low expansion coefficient, good plasticity and toughness, and is easy to cold and hot process. Its chemical composition is very important for the control of carbon and manganese. Cold deformation can reduce the thermal expansion coefficient, and heat treatment within a specific temperature range can stabilize the thermal expansion coefficient. 4J36 is corrosion-resistant in dry air at room temperature, but may corrode and rust in humid air.

The application areas of 4J36 alloy include the production, storage and transportation of liquefied gas, and it has a long record of use in the aviation industry. During use, the heat treatment and processing technology need to be strictly controlled to ensure the stability of the material. In addition, the Curie point of 4J36 alloy is about 230℃. The alloy is ferromagnetic below 230℃, non-magnetic above 230℃, and the expansion coefficient increases.

Tensile strength: The tensile strength of 4J36 alloy is usually between 490MPa and 680MPa, with high strength.

Yield strength: The yield strength of the alloy is not less than 240MPa, with good deformation resistance.

Elongation: The elongation of the alloy is generally 25% to 35%, with good plasticity.

Hardness: In the annealed state, the Brinell hardness (HB) of 4J36 alloy is between 130 and 180; in the cold rolled state, the hardness is higher, 170 to 200HB.

1. Basic characteristics
Chemical composition: 4J36 is mainly composed of nickel (Ni) and iron (Fe), of which the content of nickel is between 35.0% and 37.0%, and iron is the balance. In addition, it also contains a small amount of cobalt (Co), carbon (C), silicon (Si), manganese (Mn), phosphorus (P) and sulfur (S). The precise ratio of these elements is the key to achieving its low expansion coefficient.

Physical properties: The density of 4J36 is about 8.0 g/cm³, and the melting point ranges from 1390 to 1450°C. In the temperature range of -100°C to 200°C, its average linear expansion coefficient is about 1.2 x 10^-6 /°C, showing extremely low thermal expansion characteristics.

Mechanical properties: 4J36 has high tensile strength and yield strength, which are 490 to 680 MPa and ≥240 MPa, respectively. Its elongation is between 25% and 35%, and its hardness is 130 to 180 HB in the annealed state, and higher in the cold rolled state, 170 to 200 HB.

2. Preparation process and performance optimization
The preparation process of 4J36 includes multiple links such as batching, smelting, casting, forging, heat treatment and precision machining. Among them, the heat treatment process has an important influence on its performance.
Annealing treatment: Annealing at 900°C for 2 hours can stabilize the expansion coefficient of 4J36 at 1.2×10⁻⁶/°C (20°C to 100°C).

Aging treatment: It is usually carried out in the temperature range of 300°C to 400°C to improve the hardness and strength of the alloy. Studies have shown that after aging treatment at 350°C for 8 hours, the expansion coefficient of 4J36 can be reduced to 1.0×10⁻⁶/°C.

3. Application fields
Due to its unique properties, 4J36 is widely used in many high-tech fields:
Precision instruments: used to manufacture clocks, optical instruments and other precision measuring equipment to ensure that the measurement accuracy is not affected by temperature changes.

Aerospace: used to manufacture key components of satellites, rockets and other aerospace vehicles, such as antenna reflectors, connectors, etc.

Electronics industry: used to manufacture substrates and lead frames for electronic components and integrated circuits, as well as shadow masks that require precise dimensions.

Medical equipment: used to manufacture medical instruments and equipment that require high precision and high reliability.

Liquid gas related equipment: due to its extremely low thermal expansion coefficient, it is suitable for the manufacture of liquefied gas related equipment and containers.