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Story 136 – 2000 – Products

Smallest elements for strong currents

High performance alloys for high current contacts in cars

Previously hydraulically operated automotive components such as brakes will increasingly be replaced by electric power units in the future. Connectors with special requirements will be used which are made of high-performance alloys from Wieland.

The electrification of the car is progressing in great strides - and not only because of the increase in battery-powered electric cars. So-called power electronics are also increasingly being used in conventionally powered vehicles. This means that hydraulically supported components such as brakes or steering units are operated with electricity.

This requires high currents. The correspondingly designed cables are connected to the control units and the respective aggregates with high-current plugs. Through a complex transformation process, the plugs develop a spring force which guarantees an absolutely secure connection on the one hand, but which can be released again if necessary - for example when replacing the component.

Relaxation resistance - the property of not becoming soft or losing conductivity despite the unavoidable high temperatures due to the strong electrical currents - represents a further challenge.

These requirements are met by materials with particularly good resistance to thermal relaxation - such as the Wieland alloys K75 and K88. They are produced with a complex thermodynamic process control in the rolling-annealing cycles during which hard nickel or titanium silicide phases are precipitated. This is a major challenge when one considers that in a six tonne coil the size of all the silicides is in the range of 50 nanometres and that the uniform distribution of the silicides over the entire strip must be ensured.

High-current contacts made of high-performance alloys will play an increasingly important role in automotive engineering in the future: In purely electric vehicles, hydraulic power units are no longer used at all.