Friction stir welding method of parts with different thicknesses

Abstract

The invention provides a friction stir welding method of parts with different thicknesses. The method includes the steps of making a tack welding stirring head incline towards the side of thin parts,be aligned with a butt joint face, start to rotate and pierce into the butt joint face, making the tack welding stirring head continue rotating for 2-20 seconds along the butt joint face to complete tack welding after a shaft shoulder of the tack welding stirring head makes contact with the thin parts, replacing the tack welding stirring head with a formal welding stirring head, making the formalwelding stirring head incline towards the side of the thin parts, be aligned with the butt joint face, start to rotate and pierce into the butt joint face, and making the tack welding stirring head continue rotating for 2-20 seconds and making the formal welding stirring head rotate along the butt joint face to complete welding after a shaft shoulder of the formal welding stirring head makes contact with the thin parts. The problems that when the parts with different thicknesses are welded, welding trimmings are too large, right-angle steps appear and incomplete back welding and other defectseasily happen are effectively solved, and the economic benefits of the friction stir welding technology are improved.

Description

technical field [0001] The invention relates to the field of alloy welding, in particular to a friction stir welding method for parts with unequal thickness. Background technique [0002] Friction stir welding means that during the welding process, the heat generated by the friction between the high-speed rotating stirring head and the welded material is used to locally plasticize the welded material. When the stirring head moves along the butt joint surface, the plasticized material is A dense solid phase weld is formed under extrusion. The welding process can be divided into three stages: vertical insertion of the stirring head into the material to be welded, translational welding, and extraction. Since its invention, friction stir welding has successfully welded aluminum alloys, magnesium alloys, copper alloys, iron-based alloys, titanium alloys and other materials. However, the conventional friction stir welding process requires that the thickness of the two parts to b...

AI Technical Summary

Problems solved by technology

However, the conventional friction stir welding process requires that the thickness of the two parts to be welded be similar. For example, the general thickness difference is ≤0.5mm. Friction stir welding is then carried out, which increases the workload

If friction stir welding is performed directly on parts with different thicknesses, the stirring head will plunge into the material to be welded vertically, and a large welding flash will inevitably appear on the side of the thicker parts; There are right-angled steps between them, which is a stress concentration area, which affects the load-carrying capacity of the weld. It needs to be processed again to remove the flash and right-angled steps, and the workload is heavy. There are defects such as incomplete penetration of the back, which affects the bearing capacity of the weld joint

Therefore, the existing friction stir welding technology is not suitable for processing unequal thickness plates, which reduces the economic benefits of friction stir welding technology

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