- Materials
- Forms
- Reference Materials
-
Services
-
Services
-
-
Sectors
-
Supporting cutting edge research and development with advanced materials to your needs.
High performance materials for extreme conditions.
Innovative and lightweight materials with high mechanical properties and durability.
Materials used in chemical engineering from consumables to innovative solutions.
Advanced materials characterized by high electrical or insulation performance.
High quality materials for renewable energy.
Biocompatible and biodegradable materials to the highest standards.
High purity, biocompatible materials for high performance devices and applications.
High purity metals and alloys in various forms and crucibles suitable to your needs.
State of the art materials for the next generation of technologies.
High performance materials for extreme conditions.
Durable materials for corrosive environments.
Foils, disks or windows across a range of materials to facilitate your innovation.
Polymers, metal foils, and sustainable materials for your packaging needs.
Your requirements for unique products and attributes will be met across our 170,000+ product range and customization capabilities.
High-quality materials across branded products in various forms including rods, wires, and foils support space technology needs.
Highest quality materials to support your need for small-quantity specialist materials such as graphite and lithium compounds.
High purity materials to improve the reproducibility and reliability of your evaporation processes.
-
- Product Ranges
-
Resources
-
Find out our latest news.
Read our latest insights, and opinions.
Discover our Innovation Discovered podcasts on innovation, products, interesting topics, and more.
Find out how we've worked with our partners
Our latest updates on what we are doing, find out more.
Find out more about us and the great roles we have available for talented individuals. Find out more.
Take a look at our global distributors.
Explore our FAQ resource to help answer your key questions.
Gain a clearer picture of the language used in scientific study
-
- About Us
Constantan® Spooled Wire
Available Configurations
Properties common to all products in this list
| Diameter | Length |
|---|---|
| 0.025 mm to 1 mm | 1 m to 5,000 m |
Need custom configurations? Please contact us.
Health hazard/Hazardous to the ozone layer
Serious health hazard
Key Features
Constantan® Spooled Wire (Cu55/Ni45) is a copper-nickel precision resistance alloy wire with an electrical resistivity of approximately 49 µΩ·cm and one of the lowest temperature coefficients of resistance of any metallic alloy:
Near-Zero TCR (~0.00002 K⁻¹)
The temperature coefficient of resistance of approximately 0.00002 K⁻¹ is the defining property from which the name Constantan derives. Resistance is essentially independent of temperature across a wide range around room temperature, making it the reference material wherever resistance must remain constant regardless of ambient conditions.
Electrical Resistivity ~49 µΩ·cm
High resistivity combined with near-zero TCR makes Constantan wire well suited to winding precision resistance standards, calibration resistors, and resistance bridges where stability of the resistance value under environmental temperature variation is critical.
Stable Thermoelectric Output
Constantan’s thermoelectric output is highly stable across a wide temperature range, including at sub-zero and cryogenic temperatures. This stability is the basis for its use as the negative-leg material in multiple IEC-defined thermocouple types.
Most Widely Used Strain Gauge Sensing Element
Constantan is the most widely used gauge sensing element material in strain gauge manufacture. Its near-zero TCR minimizes apparent strain from temperature changes in the gauge, directly determining measurement accuracy in strain and stress analysis.
Industrial Applications
Constantan® Spooled Wire is used wherever near-zero temperature coefficient of resistance, stable thermoelectric output, or precise resistance values across ambient temperature ranges determine material selection:
- ✦ Type E Thermocouple Fabrication (Chromel vs. Constantan)
- Used as the negative leg in Type E thermocouples, which cover measurement ranges up to approximately 800 °C and offer the highest thermoelectric output of any standardized thermocouple type.
- ✦ Type J Thermocouple Fabrication (Iron vs. Constantan)
- Used as the negative leg in Type J thermocouples for general-purpose temperature measurement, where the iron-Constantan pair offers a cost-effective combination suited to oxidizing and reducing atmospheres up to approximately 750 °C.
- ✦ Type T Thermocouple Fabrication (Copper vs. Constantan)
- Used as the negative leg in Type T thermocouples, where Constantan’s stable thermoelectric output at sub-zero and cryogenic temperatures gives Type T its characteristic accuracy advantage in cold service and cryogenic measurement.
- ✦ Strain Gauge Sensing Elements
- The most widely used material for strain gauge sensing elements, where near-zero TCR minimizes apparent strain from temperature-induced resistance change, ensuring that gauge output reflects mechanical strain rather than thermal artifact.
- ✦ Precision Resistance Standards and Calibration Resistors
- Wound into precision resistance standards and calibration resistors where resistance stability under environmental temperature variation is the critical performance parameter, and the near-zero TCR eliminates temperature corrections from resistance measurement.
- ✦ Resistance Bridges and Precision Electronics
- Used in resistance bridge winding and precision electronic circuits where the 49 µΩ·cm resistivity and near-zero TCR provide a stable, high-resistance winding material whose value does not drift with temperature.
Material Properties
| Element | Value |
|---|---|
| Hardness - Brinell | 100-300 |
| Elongation at break( % ) | 45 |
| Modulus of elasticity( GPa ) | 162 |
| Izod impact strength( J m⁻¹ ) | 107 |
| Tensile strength( MPa ) | 400-590 |
| Element | Value |
|---|---|
| Electrical resistivity( µOhmcm ) | 52 |
| Temperature coefficient( K⁻¹ ) | 0.00002+/- |
| Element | Value |
|---|---|
| Maximum use temperature in air( C ) | 500 |
| Melting point( C ) | 1225-1300 |
| Thermal conductivity( W m⁻¹ K⁻¹ ) | 19.5@23°C |
| Coefficient of thermal expansion( x10⁻⁶ K⁻¹ ) | 14.9@20-100°C |
| Element | Value |
|---|---|
| Density( gcm⁻³ ) | 8.9 |
Tolerances
| Diameter | ±10% | |
|---|---|---|
| Length | +5% / -1% |