Laser welding method for sheet aluminum alloy and carbon fiber reinforced composite material

Abstract

The invention belongs to the technical field of welding. The invention provides a laser welding method for a thin plate aluminum alloy and a carbon fiber reinforced composite material, which comprises the following steps of: carrying out texture treatment on the surface of the thin plate aluminum alloy by adopting laser, and then carrying out retreatment by adopting hydrochloric acid and boiling water in sequence; the treated thin plate aluminum alloy and the treated carbon fiber reinforced composite material are placed in a lap joint or overlapping mode, and one end of the thin plate aluminum alloy is placed on the carbon fiber reinforced composite material and fixed; adjusting the positions of the thin plate aluminum alloy and the carbon fiber reinforced composite material through red light preview until the to-be-welded part coincides with the calibrated red light track consistent with the actual welding track; and welding. The laser welding mode is successfully used for replacing a traditional glue joint mode, the technological process is shortened, the production efficiency is improved, and meanwhile joint forming is good. In addition, the rough surface is prepared on the thin plate aluminum alloy surface, so that the strength of a welding joint is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding, in particular to a laser welding method for connecting thin plate aluminum alloy and carbon fiber reinforced composite material. BACKGROUND

[0002] With the rapid development of industry, energy crisis and environmental pollution problems are becoming more and more serious, and reducing carbon emissions has become an effective response. Lightweight is to reduce the weight of the structure under the premise of meeting the requirements of structural safety and regulations, so as to achieve the goal of reducing cost, saving energy and reducing emission.

[0003] Aluminum alloy and resin-based composite material are widely used as the first choice of lightweight material. Due to the large difference in physical and chemical properties between aluminum alloy and resin-based composite material, it is difficult to form a high-strength joint. At present, the main connection methods of metal-plastic are adhesive bonding, mechanical connection, welding and special device connection. The adhesive bonding method needs a certain curing time, and the adhesive used has volatility, which is easily affected by the use environment and can pollute the environment. The mechanical connection method needs positioning and perforation, which causes stress concentration, damages the material itself, and reduces the production efficiency and affects the service life of the material. Therefore, many researchers have begun to try to connect metal-plastic with various welding methods, such as ultrasonic welding, hot press welding, friction stir welding, etc.

[0004] With the rapid development of laser industry, laser welding is widely used as a welding method with high energy density, fast welding speed, small heat affected zone, and the ability to cooperate with robots to form automatic and intelligent welding. However, due to the difference in properties between aluminum alloy and resin-based composite material, the direct connection joint has low strength and is difficult to be applied in industry, so it is necessary to use certain interface control means to improve the performance of the welded joint. Therefore, it is of good application prospect to develop a laser welding method for connecting thin plate aluminum alloy and carbon fiber reinforced composite material directly instead of traditional adhesive bonding. SUMMARY

[0005] The purpose of the present application is to provide a laser welding method for connecting thin plate aluminum alloy and carbon fiber reinforced composite material, which can meet the quality requirements of the connection and has a high-quality welded joint.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical scheme:

[0007] The present application provides a laser welding method for connecting thin plate aluminum alloy and carbon fiber reinforced composite material, which comprises the following steps:

[0008] S1, after the surface of the thin plate aluminum alloy is textured by laser, the surface is treated again with hydrochloric acid and boiling water;

[0009] S2, the processed sheet aluminum alloy and carbon fiber reinforced composite material are placed in a lap or overlapping form, and one end of the sheet aluminum alloy is placed on the carbon fiber reinforced composite material and fixed;

[0010] S3, the position of the sheet aluminum alloy and the carbon fiber reinforced composite material is adjusted through red light preview until the to-be-welded part coincides with the red light track consistent with the calibrated and actual welding track;

[0011] S4, the parameters of laser welding are confirmed, and welding is performed.

[0012] Preferably, the power of the laser treatment in step S1 is 60-80W, the scanning speed is 450-550mm / s, and the frequency is 20-30kHz.

[0013] Preferably, the depth of the texture treatment in step S1 is 0.2-0.4mm, the width of the texture treatment is 0.4-0.6mm, and the shape of the texture treatment is bionic fish scale shape.

[0014] Preferably, after the texture treatment, the hydrochloric acid treatment and the boiling water treatment in step S1 are completed, the sheet aluminum alloy needs to be cleaned; the cleaning reagent is alcohol.

[0015] Preferably, the concentration of the hydrochloric acid in step S1 is 1-3mol / L, and the hydrochloric acid treatment time is 2-4min.

[0016] Preferably, the temperature of the boiling water in step S1 is 100℃, and the boiling water treatment time is 4-6min.

[0017] Preferably, the width of the processed sheet aluminum alloy in step S2 is 24-26mm, the length is 45-55mm, and the thickness is 1-3mm.

[0018] Preferably, the width of the carbon fiber reinforced composite material in step S2 is 24-26mm, the length is 45-55mm, and the thickness is 2-4mm.

[0019] Preferably, the parameters of the laser welding in step S4 are: the laser power is 1000-1200W, the welding speed is 3-5mm / s, and the defocusing amount is +8-12mm.

[0020] The beneficial effects of the present application are as follows:

[0021] The present application successfully uses the laser welding method to replace the traditional adhesive method of the thin plate aluminum alloy and the carbon fiber reinforced composite material, shortens the process flow, improves the production efficiency, and the joint is well formed. And, through the texture composite chemical treatment, the contact area of the thin plate aluminum alloy and the carbon fiber reinforced composite material is increased, the lubricity is improved, the solder can better contact the thin plate aluminum alloy and the carbon fiber reinforced composite material, the bonding strength between the thin plate aluminum alloy and the carbon fiber reinforced composite material is greatly improved, and better welding effect is realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A macrograph of the thin plate aluminum alloy and the carbon fiber reinforced composite material welded sample of Example 1 is shown in the figure.

[0023] Figure 2 A schematic diagram of the surface of the thin plate aluminum alloy obtained in Example 1 and Comparative Examples 1-3 is shown in the figure.

[0024] Figure 3 A schematic diagram of the laser welding strength of the thin plate aluminum alloy and the carbon fiber reinforced composite material obtained in Example 1 and Comparative Examples 1-3 is shown in the figure. DETAILED DESCRIPTION

[0025] The present application provides a laser welding method of a thin plate aluminum alloy and a carbon fiber reinforced composite material, comprising the following steps:

[0026] S1, after the surface of the thin plate aluminum alloy is treated by laser, the surface is treated again by hydrochloric acid and boiling water;

[0027] S2, the treated thin plate aluminum alloy and the carbon fiber reinforced composite material are placed in a lap or overlapping form, and one end of the thin plate aluminum alloy is placed on the carbon fiber reinforced composite material and fixed;

[0028] S3, the position of the thin plate aluminum alloy and the carbon fiber reinforced composite material is adjusted by red light preview until the to-be-welded part coincides with the red light track after calibration and the actual welding track;

[0029] S4, the parameters of laser welding are confirmed, and welding is performed.

[0030] In the present application, the power of the laser treatment in step S1 is preferably 60-80W, further preferably 65-75W, and more preferably 70W; the scanning speed is preferably 450-550mm / s, further preferably 480-520mm / s, and more preferably 500mm / s; and the frequency is preferably 20-30kHz, further preferably 24-26kHz, and more preferably 25kHz.

[0031] In the present application, the depth of the texturing treatment in step S1 is preferably 0.2-0.4 mm, further preferably 0.25-0.35 mm, and more preferably 0.3 mm; the width of the texturing treatment is preferably 0.4-0.6 mm, further preferably 0.45-0.55 mm, and more preferably 0.5 mm; and the shape of the texturing treatment is preferably a biomimetic fish scale shape.

[0032] In the present application, after the texturing treatment, hydrochloric acid treatment and boiling water treatment in step S1, the thin plate aluminum alloy is preferably cleaned; the cleaning reagent is preferably alcohol, and the cleaning function is to ensure that the welding position of the thin plate aluminum alloy and the carbon fiber reinforced composite material is not contaminated, and the lap or stacking is flat.

[0033] In the present application, the concentration of the hydrochloric acid in step S1 is preferably 1-3 mol / L, further preferably 1.5-2.5 mol / L, and more preferably 2 mol / L; and the hydrochloric acid treatment time is preferably 2-4 min, further preferably 2.5-3.5 min, and more preferably 3 min.

[0034] In the present application, the temperature of the boiling water in step S1 is preferably 100℃, and the boiling water treatment time is preferably 4-6 min, further preferably 4.5-5.5 min, and more preferably 5 min.

[0035] In the present application, before step S2, the position of the laser focus is preferably adjusted, the walking program of the laser welding equipment is adjusted through the robot teach pendant, and the laser welding trajectory and welding process parameters are set.

[0036] In the present application, the width of the treated thin plate aluminum alloy in step S2 is preferably 24-26 mm, further preferably 24.5-25.5 mm, and more preferably 25 mm; the length is preferably 45-55 mm, further preferably 48-52 mm, and more preferably 50 mm; and the thickness is preferably 1-3 mm, further preferably 1.5-2.5 mm, and more preferably 2 mm.

[0037] In the present application, the width of the carbon fiber reinforced composite material in step S2 is preferably 24-26 mm, further preferably 24.5-25.5 mm, and more preferably 25 mm; the length is preferably 45-55 mm, further preferably 48-52 mm, and more preferably 50 mm; and the thickness is preferably 2-4 mm, further preferably 2.5-3.5 mm, and more preferably 3 mm.

[0038] In the present application, the position of the thin plate aluminum alloy and the carbon fiber reinforced composite material is adjusted by red light preview in step S3 until the to-be-welded position coincides with the red light trajectory after calibration and actual welding trajectory, and the purpose is to make the welding along the required to-be-welded position.

[0039] In the present application, the parameters of the laser welding in step S4 are as follows: the laser power is preferably 1000-1200 W, further preferably 1100 W; the welding speed is preferably 3-5 mm / s, further preferably 3.5-4.5 mm / s, and more preferably 4 mm / s; and the defocusing amount is preferably +8-12 mm, further preferably +9-11 mm, and more preferably +10 mm.

[0040] The technical solutions provided by the present application will be described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0041] Example 1

[0042] A laser welding method of a thin plate aluminum alloy and a carbon fiber reinforced composite material, comprising the following steps:

[0043] S1, a laser is used to perform texture treatment on the surface of the thin plate aluminum alloy, the power of the laser treatment is 70 W, the scanning speed is 500 mm / s, the frequency is 25 kHz, the depth of the texture treatment is 0.3 mm, the width of the texture treatment is 0.5 mm, the shape of the texture treatment is bionic fish scale, and then the thin plate aluminum alloy is cleaned with alcohol; then the thin plate aluminum alloy is treated with 2 mol / L hydrochloric acid for 3 minutes, and then taken out and cleaned with alcohol; finally, the thin plate aluminum alloy is treated with boiling water at a temperature of 100℃ for 5 minutes, and then taken out and cleaned with alcohol;

[0044] S2, the position of the laser focus of the laser welding equipment is adjusted, the walking program of the laser welding equipment is adjusted through the robot teach pendant, the laser welding track and the welding process parameters are set, and in this embodiment, two laser tracks are formed to meet the requirement of welding strength.

[0045] S3, the treated thin plate aluminum alloy (the width of the thin plate aluminum alloy is 25 mm, the length is 50 mm, and the thickness is 2 mm) and the carbon fiber reinforced composite material (the width of the carbon fiber reinforced composite material is 25 mm, the length is 50 mm, and the thickness is 3 mm) are placed in a lap joint form, and one end of the thin plate aluminum alloy is placed on the carbon fiber reinforced composite material and fixed.

[0046] S4, the position of the thin plate aluminum alloy and the carbon fiber reinforced composite material is adjusted through red light preview until the to-be-welded part coincides with the red light track after calibration and the actual welding track, so that the welding is performed along the required to-be-welded part.

[0047] S5, the parameters of the laser welding are confirmed: the laser power is 1100 W, the welding speed is 4 mm / s, and the defocusing amount is +10 mm, and then the welding is performed.

[0048] The macroscopic picture of the welding sample of thin-plate aluminum alloy and carbon fiber reinforced composite material in this embodiment is as follows: Figure 1 As shown. Figure 1 It can be seen that the laser welding method can obtain a weld with beautiful joint shape, smooth and flat joint, no obvious welding defects and excellent performance.

[0049] Example 2

[0050] A laser welding method for thin-plate aluminum alloy and carbon fiber reinforced composite material comprises the following steps:

[0051] S1. The surface of the thin aluminum alloy was textured using a laser with a power of 60W, a scanning speed of 450mm / s, a frequency of 20kHz, a texture depth of 0.2mm, a texture width of 0.4mm, and a texture shape of bionic fish scales. The surface was then cleaned with alcohol. The thin aluminum alloy was then treated with 1mol / L hydrochloric acid for 4 minutes, removed and cleaned with alcohol. Finally, the thin aluminum alloy was treated with boiling water at a temperature of 100°C for 4 minutes, removed and cleaned with alcohol.

[0052] S2. Adjust the position of the laser focus of the laser welding equipment, adjust the walking program of the laser welding equipment through the robot teaching pendant, set the laser welding trajectory and welding process parameters. In this embodiment, two laser trajectories are formed to achieve the welding strength requirements.

[0053] S3. Place the treated thin aluminum alloy sheet (the thin aluminum alloy sheet has a width of 24 mm, a length of 45 mm, and a thickness of 1 mm) and the carbon fiber reinforced composite material (the carbon fiber reinforced composite material has a width of 24 mm, a length of 45 mm, and a thickness of 2 mm) in an overlapping manner, with one end of the thin aluminum alloy sheet placed on the carbon fiber reinforced composite material, and secure them;

[0054] S4. Adjust the position of the thin aluminum alloy and carbon fiber reinforced composite material through red light preview until the welding position coincides with the calibrated red light trajectory that is consistent with the actual welding trajectory, so that welding is performed along the desired welding position;

[0055] S5. Confirm the laser welding parameters: laser power is 1000W, welding speed is 3mm / s, defocus is +8mm, and perform welding.

[0056] Example 3

[0057] A laser welding method for thin-plate aluminum alloy and carbon fiber reinforced composite material comprises the following steps:

[0058] S1, the surface of the thin plate aluminum alloy is treated by laser texturing, the power of laser treatment is 80W, the scanning speed is 550mm / s, the frequency is 30kHz, the depth of texturing treatment is 0.4mm, the width of texturing treatment is 0.6mm, and the shape of texturing treatment is bionic fish scale, then the thin plate aluminum alloy is cleaned with alcohol; then the thin plate aluminum alloy is treated with 3mol / L hydrochloric acid for 2min, and then taken out and cleaned with alcohol; finally, the thin plate aluminum alloy is treated with boiling water at a temperature of 100℃ for 6min, and then taken out and cleaned with alcohol;

[0059] S2, the position of the laser focus of the laser welding equipment is adjusted, the walking program of the laser welding equipment is adjusted through the robot teach pendant, the laser welding trajectory and the welding process parameters are set, and the two laser trajectories are formed to meet the requirement of welding strength.

[0060] S3, the treated thin plate aluminum alloy (the width of the thin plate aluminum alloy is 26mm, the length is 55mm, and the thickness is 3mm) and the carbon fiber reinforced composite material (the width of the carbon fiber reinforced composite material is 26mm, the length is 55mm, and the thickness is 4mm) are placed in a lap joint form, and one end of the thin plate aluminum alloy is placed on the carbon fiber reinforced composite material and fixed.

[0061] S4, the position of the thin plate aluminum alloy and the carbon fiber reinforced composite material is adjusted through red light preview until the to-be-welded part coincides with the red light trajectory after calibration and the actual welding trajectory, so that the welding is performed along the required to-be-welded part;

[0062] S5, the parameters of laser welding are confirmed: the laser power is 1200W, the welding speed is 5mm / s, and the defocusing amount is +12mm, and then welding is performed.

[0063] Comparative Example 1

[0064] The present comparative example is basically the same as example 1, except that the surface treatment method of the thin plate aluminum alloy is as follows: the surface of the thin plate aluminum alloy is treated by laser texturing, the power of laser treatment is 70W, the scanning speed is 500mm / s, the frequency is 25kHz, the depth of texturing treatment is 0.3mm, the width of texturing treatment is 0.5mm, and the shape of texturing treatment is bionic fish scale, then the thin plate aluminum alloy is cleaned with alcohol.

[0065] Comparative Example 2

[0066] The present comparative example is basically the same as example 1, except that the surface treatment method of the thin plate aluminum alloy is as follows: the thin plate aluminum alloy is treated with boiling water at a temperature of 100℃ for 5min, and then taken out and cleaned with alcohol.

[0067] Comparative Example 3

[0068] The comparative example is basically the same as example 1, except that the surface treatment of the thin plate aluminum alloy is as follows: the thin plate aluminum alloy is treated with 2 mol / L hydrochloric acid for 3 min, and then taken out and cleaned with alcohol.

[0069] The schematic diagram of the surface of the thin plate aluminum alloy obtained in example 1 and comparative examples 1-3 is shown in Figure 2 , wherein (a) is the schematic diagram of the surface of the thin plate aluminum alloy of comparative example 1, (b) is the schematic diagram of the surface of the thin plate aluminum alloy of comparative example 2, (c) is the schematic diagram of the surface of the thin plate aluminum alloy of comparative example 3, and (d) is the schematic diagram of the surface of the thin plate aluminum alloy of example 1.

[0070] The schematic diagram of the laser welding strength of the thin plate aluminum alloy and the carbon fiber reinforced composite material obtained in example 1 and comparative examples 1-3 is shown in Figure 3 . It can be seen from Figures 2-3 that the surface of the aluminum alloy obtained by laser texturing and composite hydrochloric acid and boiling water changes, and the laser welding strength is the highest, which is 6102 N.

[0071] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A laser welding method for thin-plate aluminum alloy and carbon fiber reinforced composite material, characterized in that: The following steps are included: S1. After the surface of the thin aluminum alloy is textured by laser, it is treated again with hydrochloric acid and boiling water in sequence; S2. placing the treated thin aluminum alloy sheet and the carbon fiber reinforced composite material in an overlapping or overlapping manner, with one end of the thin aluminum alloy sheet placed on the carbon fiber reinforced composite material, and fixing them; S3. Adjust the position of the thin aluminum alloy and carbon fiber reinforced composite material through red light preview until the welding position coincides with the calibrated red light trajectory that is consistent with the actual welding trajectory; S4. Confirm the laser welding parameters and perform welding.

2. The laser welding method according to claim 1, characterized in that: The power of the laser treatment in step S1 is 60-80 W, the scanning speed is 450-550 mm / s, and the frequency is 20-30 kHz.

3. The laser welding method according to claim 1 or 2, characterized in that: The depth of the texture treatment in step S1 is 0.2-0.4 mm, the width of the texture treatment is 0.4-0.6 mm, and the shape of the texture treatment is bionic fish scales.

4. The laser welding method according to claim 3, characterized in that: In step S1, after the texturing treatment, the hydrochloric acid treatment and the boiling water treatment are completed, the thin plate aluminum alloy needs to be cleaned; the cleaning agent is alcohol.

5. The laser welding method according to claim 4, characterized in that: The concentration of the hydrochloric acid in step S1 is 1 to 3 mol / L, and the hydrochloric acid treatment time is 2 to 4 minutes.

6. The laser welding method according to claim 4 or 5, characterized in that: The temperature of the boiling water in step S1 is 100° C., and the boiling water treatment time is 4 to 6 minutes.

7. The laser welding method according to claim 6, characterized in that: The thin aluminum alloy plate after the treatment in step S2 has a width of 24 to 26 mm, a length of 45 to 55 mm, and a thickness of 1 to 3 mm.

8. The laser welding method according to claim 7, characterized in that: The carbon fiber reinforced composite material in step S2 has a width of 24 to 26 mm, a length of 45 to 55 mm, and a thickness of 2 to 4 mm.

9. The laser welding method according to claim 7 or 8, characterized in that: The laser welding parameters in step S4 are: laser power of 1000-1200 W, welding speed of 3-5 mm / s, and defocus of +8-12 mm.

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