Integral corrosion protection of friction-welded joints
AssigneeMcDonnell Douglas Corporation
InventorsRicky Lynn Martin, David Robert Bolser
Life of this patent
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Abstract
A zone of corrosion-resistant material covering a friction stir welded joint surface is provided by applying a layer of corrosion-resistant material over one or both surfaces of the workpieces being joined so that the layer covers at least the weld zone which will be rendered plastic during a friction stir welding operation. The corrosion-resistant material layer is contacted by the friction stir welding tool, and the tool causes shearing and plastic flow of the corrosion-resistant material along the surface of the welded joint. The corrosion-resistant material thus metallurgically bonds with portions of the plasticized metal so as to form a corrosion-resistant zone protecting the welded joint from exposure to corrosive environments.
Claims15
A method of friction stir welding two metal workpieces together along a joint therebetween such that the joint has a metallurgically bonded layer of corrosion-resistant material covering an outer surface of the joint, the method comprising:
- positioning the workpieces in contact with each other to define a joint therebetween along which the workpieces are to be welded together;
- defining a weld zone spanning the joint between the workpieces which is to rendered plastic for creating a metallurgical bond between the workpieces along the joint, the weld zone having an outer surface;
- covering the outer surface of the weld zone with a layer of corrosion-resistant material;
- and
- friction stir welding the workpieces together along the joint so as to plasticize the metal in the weld zone, and to cause plastic flow of the corrosion-resistant material along the outer surface of the weld zone and metallurgical bonding of the corrosion-resistant material with a portion of the plasticized metal so as to create a corrosion-resistant material covering the outer surface of the joint.
A method of friction stir welding two metal workpieces together along a lap joint therebetween such that the joint has a metallurgically bonded layer of corrosion-resistant material surrounding the joint, the method comprising:
- positioning the workpieces in overlapping relation with each other and interposing a layer of corrosion-resistant material between overlapping portions of the workpieces to form a lap joint along which the workpieces are to be welded together;
- and
- friction stir welding the workpieces together along the joint so as to plasticize the metal in the weld zone and in the corrosion-resistant material layer, the corrosion-resistant material layer metallurgically bonding with a portion of the plasticized metal so as to create a zone of corrosion-resistant material surrounding the weld zone at the lap joint.
Dependencies are inferred from the claim text.