Composite welding method of outer-layer laser beam surrounding type rotation auxiliary high-power laser

Abstract

The invention provides a composite welding method of outer-layer laser beam surrounding type rotation auxiliary high-power laser, and belongs to the technical field of laser material processing. In the welding process, the inner-layer high-power laser beam acts on the surface of a workpiece to be welded and forms a key hole, and the outer-layer low-power rotating laser beam rotates around the key hole generated by the inner-layer high-power laser beam, so that laser evaporation steam on the wall face of the key hole is accurately regulated and controlled, the wall face of the key hole is stressed more uniformly, and then collapse of the key hole is restrained. According to the outer-layer laser beam surrounding type rotation auxiliary high-power laser hybrid welding method, the welding process is more stable, the quality of obtained welding seams is high, and defects such as air holes, collapse and cracks are not prone to being formed.

Description

Technical Field

[0001] The invention relates to the technical field of laser material processing, in particular to a composite welding method of an outer laser beam surrounding rotation-assisted high-power laser. Background Art

[0002] High-power fiber lasers have attracted the attention of many scholars in the manufacturing field with their advantages of small size, good beam quality, low operating cost and high electro-optical conversion efficiency. In the field of welding manufacturing, high-power fiber laser welding technology has become one of the hottest research directions in the 21st century. After research in recent years, this technology has achieved rapid development and has shown broad application prospects in aerospace, rail transportation, automobile manufacturing and other fields. During the laser deep melting welding process, the keyhole is subjected to unbalanced energy and pressure, which will cause the keyhole to collapse and form pores. To solve the above problems, focus rotating lasers are introduced into the laser welding process. The high-frequency rotating laser focus can coordinate the laser energy input, improve the melting behavior of the molten pool, stabilize the welding process, and form high-quality welds without defects such as spatter, cracks and pores.

[0003] However, while the focus rotating laser stabilizes the welding process and optimizes the welding quality, the laser penetration ability is greatly reduced, and the weld penetration depth cannot be guaranteed to be improved. To this end, the present invention proposes a composite welding method in which an outer laser beam is rotated around and assisted by a high-power laser. During welding, an inner high-power laser beam forms a keyhole, and an outer low-power rotating laser beam performs a uniform rotation motion on the keyhole wall. The laser on the keyhole wall is regulated to cause vaporized steam, so that the keyhole wall is more evenly stressed and less likely to collapse, thereby improving the stability of the welding process. Compared with traditional laser welding methods, the welding process is stable, the quality of the weld obtained is higher, and defects such as pores, collapse and cracks are not easily formed. Summary of the invention

[0004] The purpose of the present invention is to provide a composite welding method of outer laser beam surrounding rotation assisted high-power laser, the welding process is more stable, the obtained weld quality is higher, and it is not easy to form defects such as pores, collapse and cracks.

[0005] To achieve the above-mentioned purpose, the present invention provides a composite welding method of an outer laser beam surrounding rotation-assisted high-power laser. During the welding process, the inner high-power laser beam acts on the surface of the workpiece to be welded and forms a keyhole, and the outer low-power rotating laser beam rotates around the keyhole generated by the inner high-power laser beam to accurately control the laser-induced evaporated steam on the keyhole wall, so that the force on the keyhole wall is more uniform, thereby inhibiting the collapse of the keyhole.

[0006] Preferably, the distance between the axis of the outer low-power rotating laser beam and the inner high-power laser beam is 0.01-3 mm.

[0007] Preferably, the power of the outer low-power rotating laser beam is lower than the power of the inner high-power laser beam.

[0008] Preferably, the angle between the outer low-power rotating laser beam and the inner high-power laser beam is less than 30°.

[0009] Preferably, the rotation frequency of the outer low-power rotating laser beam is 10-20000 Hz.

[0010] Therefore, the present invention adopts the above-mentioned outer laser beam surrounding rotation auxiliary high-power laser composite welding method, and the beneficial technical effects are as follows: During welding, the inner high-power laser beam forms a keyhole, and the outer low-power rotating laser beam rotates around the keyhole generated by the inner high-power laser beam to precisely control the laser-induced vapor on the keyhole wall, so that the force on the keyhole wall is more uniform, thereby inhibiting the collapse of the keyhole. Compared with traditional laser welding methods, its welding process is stable, the quality of the weld obtained is higher, and it is not easy to form defects such as pores, collapse and cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of a composite welding method of the present invention in which an outer laser beam surrounds and rotates to assist a high-power laser; Figure 2 A diagram of a device for generating an outer layer low-power rotating laser beam and an inner layer high-power laser beam provided in Example 2; Figure 3 The cross section of the weld produced by the conventional laser welding method; Figure 4 Cross section of the weld produced by the hybrid welding method using a high-power laser assisted by the outer laser beam rotating around it.

[0012] Reference numerals 1. Weld surface; 2. Molten pool; 3. Keyhole; 4. Action point of outer low-power rotating laser beam; 5. Action point of inner high-power laser beam; 6. Outer low-power laser beam; 7. Inner high-power laser beam; 8. Workpiece to be welded; 9. Vertical optical path system; 10. Outer low-power rotating laser beam; 11. Second collimating lens; 12. Beam guiding element; 13. Beam combiner; 14. Focusing lens; 15. Composite optical path system; 16. Reflector; 17. First collimating lens; 18. L-shaped optical path system; 19. First fiber laser; 20. Second fiber laser. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0014] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0015] Embodiment 1 like Figure 1 As shown, in this embodiment, the inner high-power laser beam 7 and the outer low-power laser beam 6 are initially generated by a fiber laser with a wavelength of 1070nm. The power of the outer low-power laser beam 6 is 300w, and the power of the inner high-power laser beam 7 is 3500w.

[0016] The outer low-power rotating laser beam 10 performs high-frequency, small-radius uniform circular motion, which is generated by the outer low-power laser beam passing through the beam guiding element 12. The rotation frequency of the outer low-power rotating laser beam 10 is 10-20000 Hz. The beam guiding element 12 is one of a wedge mirror and a scanning galvanometer.

[0017] The distance between the axis of the outer low-power rotating laser beam 10 and the inner high-power laser beam 7 is 0.01-3 mm. The angle between the outer low-power rotating laser beam 10 and the inner high-power laser beam 7 is less than 30°.

[0018] Under the action of the inner high-power laser beam 7, the workpiece 8 to be welded forms a keyhole 3 located inside the molten pool 2, the inner high-power laser beam action point 5 is located at the keyhole 3, and the outer low-power rotating laser beam action point 4 is located at the keyhole wall. During the welding process, the outer low-power rotating laser beam 10 rotates around the keyhole wall at a uniform speed, and the laser-induced evaporation steam on the keyhole wall is regulated to make the keyhole wall more evenly stressed and less likely to collapse, thereby improving the stability of the welding process and forming a well-formed weld surface 1.

[0019] The present invention integrates the inner layer high-power laser and the outer layer low-power laser into a whole, realizing coaxial focus rotation-assisted high-power laser composite welding based on keyhole wall regulation. During welding, the inner layer high-power laser beam forms the keyhole, and the outer layer low-power rotating laser beam performs uniform rotation on the keyhole wall. The keyhole wall laser is regulated to cause vaporized steam, so that the keyhole wall is more evenly stressed and less likely to collapse, thereby improving the stability of the welding process.

[0020] Embodiment 2 like Figure 2 As shown, this embodiment provides a method for generating an inner layer high power laser beam 7 and an outer layer low power rotating laser beam 10. The generation method is based on Figure 2 The device shown includes a vertical optical path system 9, an L-shaped optical path system 18 and a compound optical path system 15.

[0021] In the L-shaped optical path system 18, the first fiber laser 19 emits an inner high-power laser beam 7, which passes through the first collimating lens 17, then through the reflector 16, through the beam combiner 13, and then through the focusing lens 14 to reach the surface of the workpiece 8 to be welded to form a keyhole 3.

[0022] In the vertical optical path system 9, the second fiber laser 20 emits an outer low-power laser beam 6, which passes through the second collimating lens 11, and then forms an outer low-power rotating laser beam 10 through the beam guiding element 12, passes through the beam combining mirror 13, and then reaches the keyhole wall through the focusing lens 14. The beam guiding element 12 is one of a wedge mirror and a scanning galvanometer.

[0023] The outer low-power rotating laser beam 10 performs uniform rotating motion on the wall of the keyhole, regulating the laser evaporation steam on the keyhole wall to form an excellent weld.

[0024] like Figure 3 and Figure 4 The figures are the cross sections of the weld produced by the conventional laser welding method and the cross sections of the weld produced by the method of the present invention. It can be seen that the quality of the cross section of the weld produced by the method of the present invention is higher than that of the conventional method.

[0025] It is worth noting that the contents not elaborated in detail in the present invention are all prior art and are well known to those skilled in the art.

[0026] Therefore, the present invention adopts the above-mentioned outer laser beam surrounding rotation assisted high-power laser composite welding method, the welding process is more stable, the obtained weld quality is higher, and it is not easy to form defects such as pores, collapse and cracks.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A composite welding method of outer laser beam surrounding type rotation assisted high power laser, characterized in that: During the welding process, the inner high-power laser beam acts on the surface of the workpiece to be welded and forms a keyhole, and the outer low-power rotating laser beam rotates around the keyhole generated by the inner high-power laser beam to regulate the laser-induced evaporation steam on the keyhole wall, making the force on the keyhole wall more uniform, thereby inhibiting the collapse of the keyhole.

2. The outer laser beam surrounding rotation assisted high power laser hybrid welding method according to claim 1 is characterized in that: The distance between the axis of the outer low-power rotating laser beam and the inner high-power laser beam is 0.01~3mm.

3. The outer laser beam surrounding rotation assisted high power laser hybrid welding method according to claim 2 is characterized in that: The power of the outer low-power rotating laser beam is lower than the power of the inner high-power laser beam.

4. The outer laser beam surrounding rotation assisted high power laser hybrid welding method according to claim 3 is characterized in that: The included angle between the outer low-power rotating laser beam and the inner high-power laser beam is less than 30°.

5. The outer laser beam surrounding rotation assisted high power laser hybrid welding method according to claim 4 is characterized in that: The rotation frequency of the outer low-power rotating laser beam is 10~20000Hz.

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