Weld root closure method for friction stir welds
First Claim
1. A method of friction stir welding a workpiece, the method comprising:
- (a) positioning the workpiece with a proposed weld line aligned with a recess in a backing device;
(b) welding the workpiece with a tool comprising a rotating non-consumable pin having a tip, the tip of the pin penetrating material of the workpiece at least up to a rear surface of the workpiece proximate the recess in the backing device to form a weld bead comprising commingled material of the workpiece, the bead extending into the recess; and
(c) machining the bead of the weld to produce a smooth weld surface on the rear surface of the workpiece.
1 Assignment
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Accused Products
Abstract
A method of root closure of friction stir welds in all types of stir weldable materials, especially difficult to weld materials, such as non-extrudable aluminum alloy 2024, 2014, 2090 and 7075. The method includes providing a backing device that has a recess, such as a groove or channel, sized to receive the tip of the pin of the welding tool and to contain the bead of the weld being formed. The workpiece rests on the backing device, with the proposed weld line aligned with the recess. Thus, as the weld is formed, material is extruded into the recess, completing closure of the weld root, and forming a small bead on the rear side of the workpiece. Optionally, this bead may be removed by a machining process. In one embodiment, the backing device is a plate with a channel machined in its surface so that the workpiece may be temporarily affixed to the plate, with weld line aligned with the channel, for welding. In an alternative embodiment, the backing device is a roller, mounted beneath the rotating pin of the friction stir welding tool, with a circumferential groove on its exterior surface, sized to receive the pin tip and contain the weld bead as the weld is being formed.
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Citations
22 Claims
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1. A method of friction stir welding a workpiece, the method comprising:
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(a) positioning the workpiece with a proposed weld line aligned with a recess in a backing device; (b) welding the workpiece with a tool comprising a rotating non-consumable pin having a tip, the tip of the pin penetrating material of the workpiece at least up to a rear surface of the workpiece proximate the recess in the backing device to form a weld bead comprising commingled material of the workpiece, the bead extending into the recess; and (c) machining the bead of the weld to produce a smooth weld surface on the rear surface of the workpiece. - View Dependent Claims (2, 3, 4, 5, 19)
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6. A method of friction stir welding, the method comprising:
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(a) aligning a proposed weld line of a workpiece with a recess in a backing device, the recess sized to receive a tip of a pin for forming a weld; and (b) welding with a tool comprising a non-consumable rotating pin having a tip, the tip of the pin penetrating the workpiece at least up to a rear side of the material to produce a weld bead comprising commingled material of the workpiece, the bead extending into the recess. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 20)
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14. A method of friction stir welding a workpiece to produce weld root closure, the method comprising:
friction stir welding a workpiece, comprising a difficult to friction stir weld material, with a rotating tool, the tool comprising a rotating non-consumable pin and a shoulder proximal to the pin, the pin penetrating a workpiece being welded such that a tip of the pin extends into the workpiece to a depth sufficient to form an outward projecting weld bead comprising commingled material of the workpiece, the bead extending along a rear surface of the weld. - View Dependent Claims (15, 16, 17, 18)
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21. A method of friction stir welding a workpiece to produce weld root closure, the method comprising:
friction stir welding a workpiece with a rotating tool, while drawing the workpiece to and past a rotating pin and shoulder of the rotating tool by supporting the workpiece on a driven roller, the roller having a circumferential groove in its outer surface sized to accommodate the tip of the rotating pin, said pin penetrating the workpiece being welded such that said tip of said pin extends into the workpiece to a depth sufficient to form an outward projecting weld bead along a rear surface of the workpiece. - View Dependent Claims (22)
Specification