Roller electrodes for electric-resistance welding machine

A roller electrode combination according to clam 4, further including said peripherial face having an annular groove formed therein adapted to receive and laterally contain a copper wire electrode as the roller electrode rolls along the edges during welding.

A roller electrode for use in electric resistance seam welding apparatus having roller electrodes opposing one another and sandwiching therebetween overlapped edges of a metal blank curved over a full 360 degrees to a tubular configuration, the inner roller electrode comprising the combination of stator and rotor components having annular surfaces spaced apart across thin gaps, bearing means for mounting said rotor to rotate relative to said stator with movement via said gaps, a conductive liquid simultaneously contacting said annular surfaces to electrically conduct a welding current across said gaps between the components, the rotor having an exterior peripherial face adapted to cooperate with the overlapped edges of the blank and said exterior peripherial face being opposite portions of said annular rotor surfaces, the peripherial face, the annular rotor surfaces and the rotor in the region radially therebetween being formed only of a composite sintered mixture of copper (Cu) and tungsten (W), in the range of 60% tunsten/40% copper and 70% tunsten/30% copper, by weight, and a protective coating being formed on the annular rotor surfaces in contact with the conductive liquid, said protective coating being of the order between 0.0025 and 0.025 millimeters thick and being of material from the platinum (Pt) family.

An inner roller electrode for use in electric resistance seam welding apparatus having inner and outer roller electrodes opposing one another and sandwiching therebetween overlapped edges of a metal blank curved over a full 360 degrees to a tubular configuration, the combination comprising stator and rotor components formed with annular surfaces thereon spaced apart across thin gaps, bearing means for mounting said rotor to rotate relative to said stator with movement via said gaps, a conductive liquid simultaneously contacting said annular surfaces to electrically conduct a welding current across said gaps between the components, the rotor having an exterior peripherial face cooperating with the overlapped edges of the blank and said exterior peripherial face being opposite portions of said annular rotor surfaces, the peripherial face, the annular rotor surfaces and the rotor in the region radially therebetween being formed only of a composite sintered mixture of copper (Cu) and tungsten (W), in the range of 60% tunsten/40% copper and 70% tunsten/30% copper, by weight, and a protective coating being formed on the annular rotor surfaces contacting the conductive liquid, said protective coating being of the order between 0.0025 and 0.025 millimeters thick.

A roller electrode for use in electric resistance seam welding apparatus having roller electrodes opposing one another and sandwiching therebetween overlapped edges of a metal blank, comprising the combination of the roller electrode having stator and rotor components formed with annular surfaces thereon spaced apart across thin gaps, bearing means for mounting said rotor to rotate relative to said stator with movement via said gaps, a gallium dominant conductive liquid simultaneously contacting said annular surfaces and having a safe operating temperature above approximately 5-8 degrees Centigrade, the conductive liquid electrically conducting a welding current and thermally conducting heat across said gaps between the components, the stator having passage means therein suited to direct a sufficient volume of a chilled liquid coolant for cooling the roller electrode of heat buildup therein generated by welding, heater means located outside of the roller electrode and upstream thereof in a series flow circuit with the chilled coolant, and sensor means operable to activate the heater means for heating the coolant to a temperature several degrees above approximately 5-8 degrees Centigrade to preclude possible damage to the conductive liquid in the event welding ceased while coolant flow continued.