Keyhole-free friction stir welding method

Abstract

The invention discloses a keyhole-free friction stir welding method. Equipment used by the method comprises a body, two drive devices and a stirring head and is characterized in that the drive devicesand the stirring head are arranged on the body, the stirring head comprises a stirring needle and a shaft shoulder, the stirring needle is arranged in the shaft shoulder, the stirring needle and theshaft shoulder are connected with respective drive devices, the drive device is used for driving the stirring head to rotate, translate or ascend and descend and regulating welding parameters, the stirring needle and the shaft shoulder are arranged separately, and the stirring needle can relatively move along the normal of the shaft shoulder. The equipment used by the method is simple in structure, simple in operation process parameter setting, convenient to control, convenient in production observation, safe and reliable in work, capable of increasing weld joint mechanical performance and attractiveness, capable of satisfying the keyhole-free requirement of straight joint or circular joint welding and the like.

Description

technical field [0001] The invention belongs to the technical field of friction stir welding, and in particular relates to a keyhole-free friction stir welding method. Background technique [0002] Friction welding is a method in which the end faces of workpieces move and rub against each other to generate heat, so that the ends reach a thermoplastic state, and then quickly upset to complete the welding. Friction welding can easily join the same or dissimilar materials, including metals, some metal matrix composites, ceramics and plastics. The friction stir welding method is the same as the conventional friction welding, and it also uses friction heat and plastic deformation heat as the welding heat source. At the joint of the workpiece, the high-speed rotation of the stirring head makes it rub against the material of the welding workpiece, so that the temperature of the material at the joint is raised and softened, and at the same time, the material is stirred and rubbed t...

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Problems solved by technology

[0003] It should be pointed out that after friction stir welding, a keyhole with the same length and diameter as the stirring needle will be left at the final welding position. This hole seriously affects the mechanical properties and aesthetics of the weld, which greatly limits the application of friction stir welding.

In order to solve the keyhole problem, the usual method is to cut it off, but in the girth welding of important parts such as aerospace storage tanks, the keyhole part cannot be cut off at the end, and the hole must be blocked by plug repair welding technology. The position of the keyhole at the back often becomes the weak point in the weld, and the gain outweighs the gain

Existing non-keyhole friction stir welding method (for example, discloses a kind of injecting type non-keyhole friction stir welding device in CN102615417B in the Chinese hair surface patent specification) is only suitable for spot welding, still has for straight seam or circular seam welding The keyhole friction stir welding method is the main method, and the keyhole problem is inevitable

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