Copper-Chromium-Zirconium (CuCr₁Zr)

Hardenable Copper Alloy With High Conductivity and Wear Resistance

The material reaches high hardness and mechanical strength, while remaining dimensionally stable up to approximately 500 °C. At the same time, it provides reliable electrical and thermal conductivity.

The copper matrix ensures efficient current transfer. Chromium increases strength without reducing conductivity. Zirconium improves temperature resistance and lowers notch sensitivity during heat exposure.

Composition of Copper-Chromium-Zirconium

  • 29

    Copper

    Cu

    > 97%

  • 24

    Chromium

    Cr

    0.5% – 1.2%

  • 40

    Zirconium

    Zr

    0.05% – 0.15%

Key Properties

  • Mechanical Strength

    CuCrZr combines high strength with good conductivity after heat treatment. Finely dispersed CrZr precipitates hinder dislocation motion and ensure mechanical stability up to 500 °C. This makes the alloy suitable for current-carrying structural parts under thermal and mechanical stress.

  • Thermal Strength

    Unlike pure copper, which loses strength above 200 °C, CuCrZr remains stable up to 500 °C. In casting moulds, this means more cycles per tool and less risk of deformation over time.

  • Fatigue Strength

    CuCrZr offers better endurance than pure copper, especially under cyclic thermal and mechanical loads. Current collectors made from this alloy can withstand a high number of switching cycles without cracking. Its microstructure slows down crack growth.

  • Notch Sensitivity

    Zirconium reduces notch sensitivity compared to pure copper and improves strength at high temperatures. This lowers the risk of cracking near bores, groovess, and other stress concentrations. This increases the reliability of complex components under thermal stress.

Physical and Mechanical Properties

Property Name

Unit

Value

Tensile strength (Rm)

MPa

≥ 490

Yield strength (Rp0.2)

MPa

≥ 420

Elongation at break (A)

%

≥ 10

Elongation

%

10–20

Hardness (Brinell)

HBW 2.5/62.5

150–180

Hardness (Vickers)

HV

160–185

Electrical conductivity

MS/m

≥ 44

Electrical conductivity

% IACS

≥ 76

Density at 20°C

g/cm³

8.9

Melting temperature (liquidus)

°C

1070–1080

These figures represent minimum values, typical averages or defined tolerance ranges. If your application requires specific material characteristics such as a defined hardness or higher flexibility, we will develop a suitable variant in close cooperation with you. Get in touch to discuss your specifications.

  • Hot Hardness

    Brinell hardness HBW 2.5/62.5 and electrical conductivity at room temperature after annealing at 600 °C, depending on annealing time.

  • Annealing Resistance

    Brinell hardness HBW 2.5/62.5 after 30 minutes of annealing at defined temperature, measured at room temperature.

  • Conductivity

    Brinell hardness HBW 2.5/62.5 and electrical conductivity (guide values) of WIRBALIT® HF measured at room temperature after heating to 600 °C, in dependence on annealing time.

Industrial Applications

Typical use cases for CuCr₁Zr in industrial environments

  • Electrical Engineering

    High electrical conductivity, mechanical stability and heat resistance make CuCr₁Zr suitable for current-carrying parts such as power contacts, connectors and components in high-voltage systems.

  • Mechanical and Tool Engineering

    The combination of conductivity, strength and wear resistance under thermal load qualifies the alloy for use in short-circuit rings, squirrel-cage rotors, excitation rails, contact pins and current collectors.

  • Foundry and Die Casting

    Due to its high thermal conductivity, mechanical strength and low adhesion tendency, CuCr₁Zr is used for moulds in non-ferrous and grey iron casting, as well as for casting wheels in continuous casting. Suitable for short cycle times and long tool life.

  • Welding Technology

    CuCr₁Zr combines strength and thermal stability with high conductivity. It is used for electrodes, seam welding wheels and other current-carrying components in resistance welding. The extended service life reduces cleaning and replacement intervals.

CuCrZr Welding Parts

Manufacturing Process

The production of a CuCrZr rod involves multiple steps to achieve the desired material properties.

  • 1
    Step 1

    Alloy preparation

    Production begins with melting high-purity copper. Chromium and zirconium are added in precisely defined amounts. The melt is processed under protective gas or in vacuum to prevent oxidation and contamination. Precise alloy composition is critical, as both conductivity and strength are directly influenced by the alloying elements.

  • 2
    Step 2

    Casting

    Once molten, the alloy is cast using either block or continuous casting. This produces solid billets as the starting format for further processing. Uniform solidification is essential to avoid shrinkage cavities or chemical segregation.

  • 3
    Step 3

    Homogenization

    The cast billets are subjected to high-temperature annealing. This homogenisation process ensures uniform distribution of the alloying elements and eliminates segregation zones, thereby improving workability and microstructural consistency.

  • 4
    Step 4

    Hot rolling

    After homogenisation, the billets are reheated and hot rolled. This forming step refines the grain structure and enhances mechanical strength.

  • 5
    Step 5

    Cold forming

    Depending on the final product, the rods are cold worked by drawing, rolling or straightening at room temperature. This increases dimensional accuracy and material strength through strain hardening.

  • 6
    Step 6

    Heat treatment

    In the first stage, the rods are heated to 950–1000 °C to dissolve chromium and zirconium. Rapid quenching follows, typically using water. Ageing is then carried out at 450–500 °C. During this process, fine precipitates form within the copper matrix, significantly increasing strength and improving thermal stability.

  • 7
    Step 7

    Finishing

    The rods are mechanically finished by cutting to length, straightening or grinding. They are then ready for industrial use.

  • 8
    Step 8

    Quality control

    Final products undergo rigorous quality checks. Mechanical tests and structural analyses verify compliance with strength, corrosion resistance and electrical conductivity specifications.

  • 9
    Step 9

    Packaging and shipping

    CuCr1Zr rods are packed using suitable protective materials to prevent damage during transport.

This process ensures that CuCr1Zr rods develop the material characteristics required for industrial use. These include high mechanical strength, electrical conductivity, thermal stability and workability.

Talk to Our Material Specialists

In close cooperation with you, we analyse your requirements, provide comprehensive guidance and find the solution that fits your process best.

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