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WCu switching contacts

Tungsten-copper for use in circuit breakers

Our tungsten-copper (WCu) materials combine the excellent high-temperature stability of tungsten with the high electrical and thermal conductivity of copper. Tungsten-copper is therefore the ideal material for arc erosion contacts in gas-insulated and air-insulated switchgear as well as high- and medium-voltage generator circuit-breakers. WCu arc erosion contacts in the center of the arcing chamber are subjected to extreme mechanical and thermal loads. The temperature during the arc can reach ≥ 20,000 K.

Your advantages at a glance:

  • Excellent resistance to arc erosion

  • Excellent electrical conductivity

  • High strength

  • Good resilience

  • Very good thermal conductivity

  • Low thermal expansion

Typical properties and values for our WCu materials:

Material

CG15
(A15Ni)

CG20
(A20Ni)

MG20
(A20NiF)

FG20

CG25

CG30
(A30Ni)

W (% by weight)

85

80

80

80

75

70

Cu (% by weight)

15

20

20

20

25

30

Alloying additions (% by weight)

≤ 1.0

≤ 1.0

≤ 1.0

≤ 1.0

≤ 1.0

≤ 1.0

Grain size (µm)*

Up to 50

Up to 50

20 - 25

4 - 8

Up to 50

Up to 50

Density (g/cm³)

15.7

15.2

15.2

15.2

14.5

14

Hardness (HV30)

205

200

190

220

190

135

Compressive strength (N/mm²)

250

200

240

300

160

60

Electrical conductivity (m/Ωmm²)

14

16

16

16

19

22

CG : Coarse grain ; MG : Medium grain ; FG : Fine grain ; VFG : Vacuum fine grain.

Minimal arc erosion with tungsten and copper

We use the right combination of tungsten and copper to optimize the arc erosion properties. We achieve the lowest arc erosion rates with approx. 80% tungsten by weight. Depending on the voltage and current intensity and taking into account economic considerations, we set the tungsten content between 60 and 90% by weight to suit your specific requirements.

The arc erosion behavior of tungsten-copper is also influenced by the grain size of the tungsten - depending on whether it is being used as a cathode (C) or anode (A) in an SF6 or air atmosphere:

Thanks to our Ni-activated sintering process, our WCu materials have a very low susceptibility to cracking as well as excellent electrical conductivity.

Electrical conductivity of our tungsten-copper materials:

Optimized use with the right microstructure

The higher the voltage and the intensity, the more resistant to arc erosion the contact material must be. One of the ways we can influence the resistance to arc erosion of WCu is to select the right grain size of tungsten.

Ready-to-install WCu contact systems

Ready-to-install WCu contact systems

Our ready-to-install contact systems save you time on assembly. Our experts will be happy to offer advice on how you can shorten your assembly times.

Top quality to suit your requirements

Our specialists develop your personal burn-off material according to your specific requirements. We guarantee reliably high quality by means of cost-efficient sintering, back-filling, machining, joining, coating, and assembling into the final shape.

In record time – from the idea to the final product

FEM switch component

To ensure the perfect switching contact design, we combine the material data for our WCu materials with the thermal and mechanical conditions to which they will later be subjected.

In no time at all, our engineers develop switching contacts with an excellent making/breaking capacity and a particularly long service life. It goes without saying that we use state-of-the-art FEM and CAD methods for this. The FEM image shows a simulation of the mechanical load on a tulip contact by way of an example.

We work according to your specific requirements. Thanks to more efficient systems for switching contacts, we save time while increasing the power and reducing the maintenance costs of the arcing chamber.

A large number of energy technology companies have been relying on our experience for many years and we are regularly awarded for our top-class services.

Other products for energy technology

Are you interested in our other contact materials? Then please visit our product pages for switching contacts made of copper-chromium as well as for use in a vacuum: