Changes

800°C and clad (or "welded") together under high pressure <xr id="fig:Hot_cladding_of_pre_materials"/> <!--(Fig. 3.3)-->. At the interface between the two materials a non-separable bond is formed by either diffusion of the reaction partners or in liquid phase by forming a AgCu eutectic alloy when an additional brazing alloy foil is placed between the two materials. Further processing is done by rolling with required annealing steps between subsequent thickness reductions. The disadvantage of this process is the usually limited short length of final material strips.

In the ''Cold Roll-Cladding'' process the bond between the contact and carrier material is achieved by cold deformation of > 50% in one rolling pass <xr id="fig:Cold roll-cladding of semi-finished strips (schematic)"/> <!-- (Fig. 3.4)-->. The high plastic deformation causes cold welding in the boundary layer between the two materials. To increase the quality and strength of the bond a subsequent diffusion annealing is performed in most cases. This process is most suitable for clad semi-finished strips with thin contact material layers (&ge; 2 μm) and large strip length (> 100 m).

*Typical configurations of clad contact strips (<xr id="fig:Typical configurations of clad contact strips"/>)

*Dimensions (<xr id="fig:Dimensions"/>)

Strength properties and dimensional tolerances of clad contact bi-metals are derived from the standards DIN EN 1652 and DIN EN 1654 for Cu alloys. Whenspecifying the width of the contact material layer it is recommended to use the minimum required value. All dimensions should be specified originating from one strip edge.