Dissimilar element mechanical and electrical connection and method

Abstract

A connection is provided between two dissimilar elements, such as an aluminum bus and a copper contact. Also provided is a method and apparatus for making the connection. One application is as an anode electrode hanger in an electric smelting furnace. The connection provides a lower resistance electrical connection which can be made while the power to the system is on. In a preferred form the contact is inserted and clamped in the bottom of a chamber in a refractory mold assembly. The chamber opening to the face of the mold assembly is somewhat deeper than the contact. The face of the mold assembly is clamped against the bus, and exothermic weld material is ignited to form a molten metal which drops into the chamber between the contact and bus. The weld metal forms a molecular weld bond with the bus, but only a mechanical interlock with the contact. To enhance the mechanical interlock and to improve the electrical conductivity, the surface area of the contact exposed to the weld metal is significantly increased, and the interlock formed increases both the strength of the connection and its electrical conductivity. The surface area increase is obtained by forming a series of parallel vertical undercut slots in the surface of the contact exposed to the weld metal, and such surface may also be tinned to form a brazed mechanical connection. The connection of the dissimilar metals can be made without shutting off the power and provides improved electrical conductivity.