Gm Global Technolgoy Operations, Inc.

Mark T Hall

Robert T Szymanski

Yen-Lung Chen

Sri Krishna Chimbli

David R Sigler

Blair E Carlson

Xiaohong Gayden

Joseph M Lendway, Iv

Mark D Gugel

Gregory J Zywicki

Corey C Holupko

Robert L Totten

Gregory A Fischer

When a friction stir weld tool penetrates the interface of two workpieces of dissimilar metal alloy materials, the resultant weld of the different alloy materials may produce a weak weld joint. Such weak joints are often experienced, for example, when attempting to form spot welds or other friction stir welds between a magnesium alloy sheet or strip and an aluminum alloy sheet or strip. It is discovered that suitable coating compositions including an adhesive placed at the interface of assembled workpieces can alter the composition of the friction stir weld material and strengthen the resulting bond. In the example of friction stir welds between magnesium alloy and aluminum alloy workpieces, it is found that combinations of an adhesive with copper, tin, zinc, and/or other powders can strengthen the magnesium-containing and aluminum-containing friction stir weld material.

Friction stir welding of dissimilar metals

A tool peels apart a sample weld between a top sheet and a bottom sheet of metal while the bottom sheet is held in a vise. The tool includes a wheel having a peripheral rim surface. A handle is attached to the wheel so that rotating the handle rotates the wheel. A clamping mechanism is mounted on the wheel and moves between an open position spaced from the peripheral rim surface and a closed position in which the clamping mechanism clamps the top sheet to the peripheral rim surface so that rotation of the wheel by the handle will progressively wrap the top sheet about the peripheral rim of the wheel and thereby forcibly peel the top sheet away from the bottom sheet to pull apart the weld between the top and bottom sheets.

Tool for peeling apart a weld sample

A device for use with a welding apparatus, such as a friction stir spot welding (FSSW) apparatus, that maintains work pieces in a generally flat or flush orientation during a welding operation. The device can be mounted to the operable end of an FSSW apparatus so that it exerts a stabilizing force against an upper work piece. The stabilizing force exerted by the device prevents the upper work piece from deflecting when the rotating tool of the FSSW apparatus passes through the upper work piece and penetrates into the lower work piece. In an exemplary embodiment, the device includes a housing component that slidably receives a movable component under the force of a biasing component.

Device for use with a friction stir spot welding (FSSW) apparatus

A method of performing a plurality of friction stir spot welds with a friction stir spot welding (FSSW) system includes measuring a length of a pin of a weld tool of the FSSW system. The length is compared to a first limit to determine if the length is above or below the first limit. Debris is removed off of a tip of the pin when the length is determined to be above the first limit. The length is also compared to a second limit to determine if the length is above or below the second limit. At least one friction stir spot weld is performed on a workpiece when the length is determined to be less than the first limit and above the second limit.

Method of calibrating a friction stir spot welding system

The present invention provides an apparatus and improved method of friction stir spot welding that assures a predetermined bottom thickness and a reduction in variation in a series of resultant spot welds. The advantage of the present invention lies in that the plunge distance is controlled from the top plane of the anvil against which the bottom thickness is specified, and systematically adjusted to account for changing system parameters, such as, but not limited to, deflection and thermal expansion of the weld gun. The present invention also provides for improved and controlled weld quality through implementation of a dwell operation or dwell operations, whereby weld heat input is manipulated by causing the weld tool to dwell in a dwell region or at a desired depth or depths within the workpiece(s) for a predetermined time interval to achieve desired mechanical properties of the resultant weld joint.

Apparatus and method of solid-state welding

Friction stir welding using an adhesive, copper, tin and zinc interlayer

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Troy, MI, United States of America

Mark T Hall