Resistance welding fastener, apparatus and methods
AssigneeArconic Inc.
InventorsDonald J. Spinella, Daniel Bergstrom
Life of this patent
Estimating the term…
Abstract
An apparatus and method for fastening dissimilar metals like steel and aluminum utilizes a steel rivet and a spot welding machine. The rivet and metals are stacked and the heat from the welder's electric current softens the lower melting point aluminum allowing the rivet to penetrate the aluminum and weld to the steel layer. The fastener may be used to join stacks with several layers of different materials and may be used to apply a threaded socket or stud made from steel or titanium to an aluminum or magnesium alloy structure. Layers of non-conductive materials like plastic and ceramics may also be affixed to a conductive layer using the fastener made from a compatible material that extends through a pilot hole.
Claims44
A method for fastening a first material to a second electrically conductive material using electrical resistance welding, comprising:
- forming a pilot hole in the first material;
- placing the first and second materials together in a stack;
- placing an electrically conductive fastener with a cap having a downwardly extending peripheral lip and a shaft that is weldable to the second material in electrical contact with the second material by extending the fastener through the pilot hole, the first material and the second material being dissimilar, the first material being less compatible for welding to the fastener than the second material;
- compressing the fastener and simultaneously applying an electrical potential across the fastener and the second material, inducing a current to flow through the fastener and the second material causing resistive heating, the resistive heating during the step of compressing causing the fastener to weld to the second material forming a weld and simultaneously softening and collapsing the shaft until the peripheral lip of the cap contacts the first material, the peripheral lip of the cap capturing material extruded from the pilot hole during the step of forming the weld.
Dependencies are inferred from the claim text.