Multi-layer forged and pressed stirring head for friction stir welding

[0023] The present invention will be further described in detail below with reference to the drawings and specific embodiments of the specification.

[0024] Figure 1 to Figure 4 An embodiment of the multi-layer forging type stirring head for friction stir welding of the present invention is shown, which includes a clamping portion 1, a shoulder portion 2 and a stirring needle 3 connected in sequence, and a spiral is provided on the circumference of the stirring needle 3 The top surface of the groove 31 and the spiral groove 31 forms a forging surface 32. During welding, the clamping part 1 is used for clamping, the stirring pin 3 generates heat energy by rotating friction, and the shoulder part 2 is used to form forging. Compared with the traditional structure, the stirring head forms a multilayer spiral groove 31 on the peripheral side of the stirring needle 3, and the top surface of the spiral groove 31 forms a forging surface 32, which is brought about by the multilayer forging surface 32 of the stirring needle 3 during the welding process. The multi-layer forging pressure achieves more uniform stirring, and the metal inside the weld flows more fully up and down, so that the weld structure is more uniform in the depth direction. At the same time, the forging pressure of the shoulder 2 can be reduced, and the amount of down pressure can be reduced. , Reduce the thickness of welding flash. Its structure is simple and reliable, and it is suitable for welding of thick plates, large plates, products requiring a small amount of pressure, and products requiring relatively uniform mechanical properties.

[0025] In this embodiment, the forging surface 32 is a flat surface, and during welding, the forging surface 32 is horizontal and straight. This arrangement can increase the contact area between the forging surface 32 and the workpiece, and further improve the stability of the welding pressure.

[0026] In this embodiment, the axis of the stirring needle 3 is defined as the rotation centerline 33, and a forging angle a is formed between the forging surface 32 and the rotation centerline 33, 76.5°≤a≤95°. In this embodiment, in the welding state, a welding inclination angle b is formed between the rotation center line 33 and the vertical line 4, 1.5°≤b≤5°. In this embodiment, in the welding state, an included angle c is formed between the forging surface 32 and the vertical line 4, and 75°≤c≤90°. When welding, the stir welding inclination b increases by 1°, and the forging angle a increases by 1°-3°; when the stir welding inclination b remains unchanged, the forging angle a decreases, and the included angle c between the forging surface 32 and the vertical line 4 decreases. When the welding inclination angle b decreases, the forging angle a increases, and the included angle c between the forging surface 32 and the vertical line 4 increases, and vice versa. The spiral angle of the conventional stirring head is 55°-65°. In terms of increasing the welding temperature and welding speed at the same time, it is necessary to increase the stirring strength, that is, increase the stirring speed and increase the upsetting force to improve the mechanical energy conversion per unit time. However, the increase of the stirring intensity will bring about two negative effects: one is that the surface plastic metal overflows from the edge of the stirring head under the action of pressure and centrifugal force to form flash; the other is that the metal in the weld area is lost due to metal loss and cannot be filled. Full, and the formation of loose tissue or even hollow. In this embodiment, a=80, b=4°, and c=75°.

[0027] In this embodiment, the diameter of the tip portion 34 of the stirring needle 3 is defined as L1, and the diameter of the root portion 35 of the stirring needle 3 is defined as L2, and L1

[0028] Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent implementation of equivalent changes. example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention should fall within the protection scope of the technical solution of the present invention.