Roller electrodes for electric-resistance welding machine

For use in electric resistance seam welding apparatus adapted to weld overlapped edges of a metal blank curved over a full 360 degrees to a tubular configuration, an improved roller electrode having stator and rotor components, the 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 roller electrode being adapted to be disposed inside of the tubular configuration and said rotor having an exterior peripheral face adapted to cooperate with the overlapped edges of the blank and said exterior peripherial face being opposite portions of said annular rotor surfaces, a protective coating being formed on said portions of the annular rotor surfaces, said protective coating being of the order between 0.0025 and 0.025 millimeters thick and being of gold (Au) plated directly on the surfaces of the rotor and rhodium (Rh) plated on the gold, and said conductive liquid being of a composite eutectic mixture of gallium (Ga), indium (In), tin (Sn) and zinc (Zn), by weight, being substantially 61% Ga, 25% In, 13% Sn, and 1% Zn.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, the stator and rotor components having annular surface 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, a protective coating formed only on said annular rotor surfaces and the annular stator surfaces being without any protective coating, said protective coating being of the order between 0.0025 and 0.025 millimeters thick, and said protective coating being of gold (Au) plated directly on the said annular rotor surfaces and material from the platinum (Pt) family then being plated on the gold.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, the 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 sad annular surfaces to electrically conduct a welding current across said gaps between the components, a protective coating formed only on said annular rotor surfaces and the annular stator surfaces being without any protective coating, said protective coating being of the order between 0.0025 and 0.025 millimeters thick, and said protective coating being of gold (Au) plated directly on the annular rotor surfaces and rhodium (Rh) plated then on the gold.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, the 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 a components, a protective coating formed only on said annular rotor surfaces and the annular stator surfaces being without any protective coating, said protective coating being of the order between 0.0025 and 0.025 millimeters thick, said protective coating being of gold (Au) plated directly on the said annular rotor surfaces and material from the platinum (Pt) family then being plated on the gold, and said rotor and stator being formed of different materials, said rotor being formed of a material durable under high temperatures and pressures, and electrically and thermally conductive;

• and said stator being formed of a material having less durability under high temperatures and pressures, but having greater electrical and thermal conductivity, than the material forming the rotor.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, the 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, a protective coating formed only on said annular rotor surfaces and the annular stator surfaces being without any protective coating, said protective coating being of the order between 0.0025 and 0.025 millimeters thick, said protective coating being of gold (Au) plated directly on the annular rotor surfaces and rhodium (Rh) then being plated on the gold, and said electrically conductive liquid being of a composite eutectic mixture of gallium (Ga), indium (In), tin (Sn) and zinc (Zn), by weight, being substantially 61% Ga, 25% In, 13% Sn, and 1% Zn.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal blank edges, an improved roller electrode having stator and rotor components, the 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, a protective coating formed on certain of said annular rotor surfaces that would contact the conductive liquid, said protective coating being of the order between 0.0025 and 0.025 millimeters thick and being of gold (Au) plated directly on the annular rotor surfaces and of material from the platinum (Pt) family then being plated on the gold, and said conductive liquid being mercury (Hg).

For use in electric resistance seam welding apparatus adapted to weld overlapped metal blank edges, an improved roller electrode having stator and rotor components, the 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, a protective coating formed on certain of said annular rotor surfaces, said protective coating being of the order between 0.0025 and 0.025 millimeters thick, and said protective coating being of gold (Au) or material from the platinum (Pt) family.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, and 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, said rotor having an exterior peripherial face adapted to be closely adjacent the overlapped metal edges during welding, certain of said annular surfaces of the rotor being opposite to the peripherial rotor face, and the rotor specifically in the region radially between said certain annular surfaces and the peripherial face being formed only of a composite sintered mixture of copper (Cu) and tungsten (W), in the range of 60-70% tungsten and 40-30% copper, by weight.

For use in electric resistance seam welding apparatus adapted to weld overlapped metal edges, an improved roller electrode having stator and rotor components, the 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, said rotor having an exterior peripherial face adapted to be closely adjacent the overlapped metal edges during welding, passage means in the rotor for a thermally conductive, said passage means being spaced from the peripherial rotor face and the rotor specifically in the region radially between said peripherial face and the rotor passage means being formed only of a composite sintered mixture of copper (Cu) and tungsten (W), in the range of 60-70% tungsten and 40-30% copper, by weight.