Precision Kovar 4j33 Co257 Round Steel Expansion Alloy Bright Bar Iron Nickel

Product Specification

Kovar 4J33 round bar Co257 round steel expansion alloy light bar iron nickel alloy bar.

Chemical composition
The main chemical components of 4J33 alloy include iron (Fe), nickel (Ni), cobalt (Co) and a small amount of other elements. Specifically, the approximate range of its chemical composition is:
Nickel (Ni): 32.1%~33.6% (some data also mention the range of 29.0%~33.6%)

Cobalt (Co): 14.0%~15.2% (some data also mention the range of 16.0%~18.0%)

Iron (Fe): balance

Carbon (C): ≤0.05%

Phosphorus (P): ≤0.02%

Sulfur (S): ≤0.02%

Manganese (Mn): ≤0.50% (or ≤0.6%)

Silicon (Si): ≤0.30%

The main chemical components of 4J33 alloy include nickel (Ni), cobalt (Co), iron (Fe), and a small amount of other elements such as silicon (Si), manganese (Mn), carbon (C), etc. Specifically, the chemical composition of 4J33 alloy is as follows:

‌Nickel (Ni) ‌: about 32.1%-33.6% ‌Cobalt (Co) ‌: about 14.0%-15.2% ‌Iron (Fe) ‌: balance ‌Carbon (C) ‌: ≤0.05% ‌Phosphorus (P) ‌: ≤0.020% ‌Sulfur (S) ‌: ≤0.020% ‌Manganese (Mn) ‌: ≤0.50% ‌Silicon (Si) ‌: ≤0.30% ‌These components make 4J33 alloy have low thermal expansion coefficient and excellent mechanical properties, widely used in the manufacture of electron tubes, magnetron electrodes, etc., and sealed with ceramics such as Al₂O₃.

Physical properties
4J33 alloy has a series of excellent physical properties, as follows:
Density: 8.27g/cm³

Melting point: 1450℃

Thermal conductivity: 17.6W/m•℃ (at 100℃)

Elastic modulus: 139GPa

Thermal expansion coefficient: In the temperature range of -60℃ to 600℃, 4J33 alloy has a linear expansion coefficient similar to that of 95% Al2O3 ceramics, and its α (20~100℃) = (4~11)×10^-6℃-1

Mechanical properties
After solution treatment, the minimum mechanical properties of 4J33 alloy at room temperature are:
Tensile strength: 539MPa

Yield strength: 343MPa

Elongation: 32%

In addition, the alloy also has a high elastic modulus and good plasticity and toughness, and can withstand certain mechanical stress and deformation.

Magnetic properties
4J33 alloy has high magnetic permeability and low hysteresis loss, which makes it widely used in high-precision magnetic equipment such as magnetic sensors and magnetic components. At the same time, its extremely low magnetostriction coefficient means that the size of the alloy changes very little under the action of an external magnetic field, making it very suitable for making precision electronic devices that require high stability.

Corrosion resistance
The elements such as Cr and Mo in the alloy give 4J33 good corrosion resistance, which can maintain structural integrity and stable performance in a variety of corrosive environments.

Processing and welding properties
4J33 alloy has good processing and welding properties, and can be cut, bent and drilled by various mechanical processing methods. At the same time, it can be brazed, fused, and resistively welded with copper, steel, nickel and other metals, which makes it have significant advantages in manufacturing complex structures and electronic devices that need to be connected. In addition, the alloy also has good electroplating properties, and the surface can be plated with metals such as gold, silver, nickel, and chromium.

Application fields
Due to the unique properties and advantages mentioned above, 4J33 alloy is widely used in many fields:
Electronic field: used to manufacture electronic devices such as electron tubes and magnetron electrodes, and to match and seal with ceramics such as Al2O3.

Aerospace field: used to manufacture electrodes, lead plates and lead wires of large electron tubes and magnetrons, and as an important sealing structure material.

Instrumentation field: used to manufacture high-precision magnetic instruments such as magnetic sensors, magnetometers, magnetic tables and magnetic springs.

Other fields: can also be used to manufacture high-frequency equipment such as high-frequency inductors, high-frequency transformers, high-frequency oscillators, as well as high-precision navigators, aviation instruments, motors, high-temperature sensors and other fields.

In summary, 4J33 (Kovar alloy), as an important iron-nickel-cobalt expansion alloy, plays an important role in materials science and industrial technology with its unique properties and broad application prospects.