Welding a ferrule on the end of braided wire is done frequently to reduce the cost of assembly of electrical devices. Unfortunately, published process are not available.
The ferrule and the wire are copper or copper alloy. They may be coated with a plate or a varnish. Since heat in resistance welding is generated by resistance, resistance welding copper does not generate heat readily. People that perform ferrule welding generate the heat by using a hot electrode like RWMA Class 14 – Molybdenum.
REFRACTORY FACED ELECTRODES
The heat is generated in the electrode, which then is transmitted into the ferrule and the wires. As they heat up the ferrule plate and wire varnish is melted or burned away and the wires and ferrule begin to bond under the pressure of the welder.
The actual weld conditions/schedule will have to be developed by trial and error.
Reference: RWMA Resistance Welding Manual 4th Edition