Standard: YB/T 5241-2005
Low expandable alloys, such as Grades 4J32 and 4J36, are specially engineered to minimize expansion under temperature fluctuations, making them ideal for applications that demand high precision in a changing ambient environment. Their ability to maintain dimensional stability under varying temperatures makes these alloys particularly suited for high-precision instrument parts, length standards, and thermostat rods.
Key Applications
These alloys are utilized in fields that require stability in both size and performance, especially under fluctuating ambient temperatures. Common applications include:
Standards of Length: Ensuring measurement accuracy even in varied temperature conditions.
Thermostat Rods: Providing reliable response in thermostatic controls.
High-Precision Instrument Parts: Used in critical applications where dimensional stability is essential.
Chemical Composition (4J32 & 4J36)
The table below summarizes the primary chemical compositions of Grades 4J32 and 4J36.
Grade | C (%) | Si (%) | P (%) | S (%) | Cu (%) | Se (%) | Mn (%) | Ni (%) | Co (%) | Fe |
4J32 | ≤0.05 | ≤0.20 | ≤0.02 | ≤0.02 | 0.40-0.80 | --- | 0.20-0.60 | 31.5-33.0 | 3.20-4.20 | Bal |
4J36 | ≤0.05 | ≤0.30 | ≤0.02 | ≤0.02 | --- | --- | 0.20-0.60 | 35.0-37.0 | --- | Bal |
In this context:
Fe (Iron) forms the base material for both alloys.
Nickel (Ni): Contributes to reduced thermal expansion, providing the alloys with their unique stability.
Cobalt (Co): Present in 4J32, it further enhances thermal stability and mechanical strength.
Unique Properties
Dimensional Stability: The primary benefit of these alloys is their capacity to resist changes in size across a wide temperature range.
High Precision in Instrumentation: Ensures that parts made from these alloys meet strict tolerance requirements.
Temperature Resilience: Effective even under substantial temperature shifts, which is critical in precision applications.
Summary
Low expandable alloys like 4J32 and 4J36 are essential materials in high-precision engineering, where minimal thermal expansion and consistent performance are paramount. Their unique chemical compositions, in alignment with YB/T 5241-2005 standards, make them reliable choices for length standards, thermostat rods, and other vital components in a range of precision applications.