摘要 |
Two or more pieces of wire of precious and non-precious metals are cold welded at their free ends, for producing a composite electrical contact or contact material, contact surface of which is made of said precious metal or alloys thereof. One of, a plurality of, or all of said free ends are provided with one or more projections of a diameter less than that of the wires which are expanded and flow under welding pressure over the abutting surfaces of the free ends to form bonded surfaces of wires without undesired or unexpected expansion of the wire pieces in their diameters. |