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What materials are suitable for percussive arc welding and how should they be prepared?

   

Due to the speed of formation and nature of the weld, a wide variety of metals can be joined using percussive arc welding. As well as joining like to like materials, the process can be used for dissimilar combinations such as nickel to aluminium, nickel/silver alloy to nickel and tinned copper to brass.

Component preparation

(Also see FAQ: What is percussive arc welding and what is it used for?)

Experiments have shown that correct preparation of the end of the pin component can increase joint strength, especially in the case of larger wires (up to 2mm diameter). As the wire diameter increases, there is less certainty about complete melting of the pin's end. This can be caused by the welding arc forming between a point on the edge of the pin's circumference and the target. Under these conditions, the central area of the pin fails to reach melting temperature. 

To overcome this condition, end preparation of the pin is recommended (see illustration). The simplest way is to cut the pin using wire cutters. The resulting profile, similar to a rooftop, concentrates the arc.

The best geometry is a conical point which ensures that arc initiation is at the centre of the pin's cross-section. It is important to optimise the cone angle so that during the weld cycle the point is consumed and a full diameter melt is achieved.

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