What Is CuNi30Mn
CuNi30Mn is a low-resistance heating alloy widely used in low-voltage circuit breakers, thermal overload relays, and other low-voltage electrical products, where it is one of the key materials. The alloy provides good resistance consistency and superior stability, and is supplied as round wire, flat wire, and sheet materials.
Chemical Composition
The composition is nickel 30 percent, manganese 1.0 percent, with copper as balance. The alloy is produced to comply with the requirements of the RoHS directive for restricted substances, with cadmium, lead, mercury, and hexavalent chromium all below detectable limits.
Electrical and Physical Properties
The maximum continuous service temperature is 350 degrees C, resistivity at 20 degrees C is 0.35 ohm square millimeters per meter, density is 8.9 g per cubic centimeter, thermal conductivity is 10 W per meter per Kelvin maximum, and melting point is 1170 degrees C. The electromotive force against copper over 0 to 100 degrees C is minus 37 microvolts per degree C, making the alloy suitable for low-EMF applications.
Mechanical Properties
In the annealed, soft condition the tensile strength is 400 MPa with elongation of 25 percent maximum. The microstructure is austenitic and the material is non-magnetic, which is important for precise resistance behavior in electrical devices.
Applications
CuNi30Mn is used in thermal overload relays, low-voltage circuit breakers, heating elements in electrical protection devices, and resistance components where stable, repeatable resistance is required over long service life.
Why Resistance Consistency Matters
In thermal protection devices, the heating element must generate a predictable amount of heat at a given current. Tight control of resistivity and its temperature coefficient ensures that trip characteristics remain accurate and consistent across production batches and operating temperatures.
Frequently Asked Questions
Q: What is the nickel content of CuNi30?
A: 30 percent with 1.0 percent manganese.
Q: What is the resistivity?
A: 0.35 ohm square millimeters per meter at 20 degrees C.
Q: What is the maximum service temperature?
A: 350 degrees C continuous.
Q: Is CuNi30Mn magnetic?
A: No, it is non-magnetic with an austenitic structure.
Q: What applications use this alloy?
A: Circuit breakers, thermal overload relays, and protection devices.
Q: What is the melting point?
A: 1170 degrees C.
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