阅读说明：本技术 一种利用三光束激光进行铝/钢焊接的焊接方法 (Welding method for aluminum/steel welding by using three-beam laser ) 是由 王文权 杜明 张新戈 王岩新 毕英超 刘亮 王苏煜 林珈名 程派 于 2020-06-04 设计创作，主要内容包括：本发明提供了一种利用三光束激光进行铝/钢焊接的焊接方法,它包括如下步骤：1)选择焊接母材和保护气体；2)用砂纸对铝合金板和钢板表面进行打磨；3)对打磨处理过的铝合金板先碱洗后酸洗,然后用酒精擦拭,再烘干；对打磨处理过的钢板用丙酮进行擦拭,再烘干；4)将铝合金板和钢板置于夹具上进行固定；5)采用激光束Ⅰ、激光束Ⅱ和激光束Ⅲ三束激光进行焊接；6)焊后检验与分析。该焊接方法中的焊接工艺简单,母材变形量小,提高了焊缝成形,缩短了焊接时间,并且提高了生产效率,有效节约了生产成本。(The invention provides a welding method for aluminum/steel welding by using three-beam laser, which comprises the following steps: 1) selecting a welding base metal and a protective gas; 2) polishing the surfaces of the aluminum alloy plate and the steel plate by using abrasive paper; 3) firstly, carrying out alkali washing and acid washing on the aluminum alloy plate after polishing treatment, then wiping the aluminum alloy plate with alcohol, and then drying the aluminum alloy plate; wiping the polished steel plate with acetone, and drying; 4) placing the aluminum alloy plate and the steel plate on a clamp for fixing; 5) welding by using three laser beams, namely a laser beam I, a laser beam II and a laser beam III; 6) and (5) inspecting and analyzing after welding. The welding method has the advantages of simple welding process, small deformation of the base metal, improvement of weld forming, shortening of welding time, improvement of production efficiency and effective saving of production cost.)

1. A welding method for aluminum/steel welding by using three-beam laser is characterized in that: it comprises the following steps:

1) selecting a welding base metal and a protective gas: the welding parent metal is an aluminum alloy plate and a steel plate, and the protective gas is argon with the purity of 99.99 percent;

2) polishing the surfaces of the aluminum alloy plate and the steel plate by using abrasive paper;

3) firstly, carrying out alkali washing and acid washing on the aluminum alloy plate after polishing treatment, then wiping the aluminum alloy plate with alcohol, and then drying the aluminum alloy plate; wiping the polished steel plate with acetone, and drying;

4) placing the aluminum alloy plate and the steel plate on a clamp for fixing;

5) welding by adopting three laser beams, namely a laser beam I, a laser beam II and a laser beam III, wherein the laser beam I is emitted by a high-power semiconductor laser, the laser beam I acts on the aluminum alloy plate, and the inclination angle of the laser beam I relative to the aluminum alloy plate is an acute angle; the laser beam II is a laser beam emitted by a single-mode fiber laser, and vertically acts on a gap between the aluminum alloy plate and the steel plate; the laser beam III is a laser beam emitted by a pulse laser, the laser beam III acts on the steel plate, and the inclination angle of the laser beam III relative to the aluminum alloy plate is an obtuse angle;

6) and (5) inspecting and analyzing after welding.

2. The welding method of claim 1, wherein the welding method comprises: the laser beam I acts on the aluminum alloy plate at a position 0.3-0.4 mm away from a gap between the aluminum alloy plate and the steel plate, and the inclination angle of the laser beam I relative to the aluminum alloy plate is 45 degrees.

3. The welding method of aluminum/steel welding using three-beam laser as set forth in claim 2, wherein: the laser beam III acts on the steel plate at a position 0.1-0.2 mm away from a gap between the steel plate and the aluminum alloy plate, and the inclination angle of the laser beam III relative to the aluminum alloy plate is 135 degrees.

4. A welding method for aluminum/steel welding using a three-beam laser as defined in claim 1, 2 or 3, wherein: the protective gas I of the laser beam I is at an inclination angle of 45 degrees relative to the aluminum alloy plate, the protective gas II of the laser beam II is at an inclination angle of 90 degrees relative to the aluminum alloy plate, and the protective gas III of the laser beam III is at an inclination angle of 135 degrees relative to the aluminum alloy plate.

5. The welding method of aluminum/steel welding using three-beam laser as set forth in claim 4, wherein: the diameter of the light spot of the high-power semiconductor laser is 0.8-1.2 mm, the diameter of the light spot of the single-mode fiber laser is 0.5-1.0 mm, and the diameter of the light spot of the pulse laser is 0.1-1.0 mm.

6. The welding method of claim 5, wherein the welding method comprises: the wavelength of the high-power semiconductor laser is 690-980 nm; the wavelength of the single-mode fiber laser is 1060-1070 nm; the wavelength of the pulse laser is 1.064um, the pulse width is 0.1-20 ms, and the pulse current is 50-600A.

7. The welding method of claim 6, wherein the welding method comprises: the width of a gap between the aluminum alloy plate and the steel plate is less than 0.05 mm.

8. The welding method of claim 7, wherein the welding method comprises: the flow of protective gas is 16-20L/min, the power of the high-power semiconductor laser is 3KW, the power of the single-mode fiber laser and the power of the pulse laser are both 2KW, and the welding speed of the laser beam I, the laser beam II and the laser beam III is 50-200 mm/s.

9. The welding method of claim 8, wherein the welding method comprises: the thickness of the aluminum alloy plate and the steel plate is 0.8-3 mm.

Technical Field

The invention relates to a welding method for aluminum/steel welding by using three-beam laser, belonging to the technical field of aluminum/steel dissimilar metal welding.

Background

Aluminum alloy has the advantages of light weight, good thermal conductivity, good corrosion resistance and the like, while steel is a main traditional material in the manufacturing industry and has the advantages of high strength, good toughness, wide adaptability and the like. The aluminum alloy and the steel are connected, so that the advantages of the aluminum alloy and the steel can be exerted, and the light weight of the product can be realized on the premise of ensuring the connection performance, so that the aluminum alloy and the steel have wide application prospects in the fields of automobiles, rail transit, aerospace and the like.

Although aluminum alloy and steel can be connected by a conventional mechanical method (such as riveting), the connecting joint has the problems of poor air tightness, surface quality and the like, and the requirement of industrial manufacturing is difficult to meet. However, when the welding method is adopted, since the solid solubility between the aluminum alloy and the steel is low and the difference in thermo-physical properties is large, brittle intermetallic compounds are easily generated at the interface of the welded joint, thereby degrading the performance of the welded joint. In recent years, many researchers at home and abroad have proposed solid-phase welding methods such as friction stir welding, ultrasonic welding, and magnetic pulse welding, and liquid-solid welding methods such as diffusion bonding welding and friction stir brazing to achieve aluminum/steel bonding and reduce the amount of brittle intermetallic compounds formed at the interface thereof. Research shows that the methods can realize aluminum/steel connection and reduce the generation thickness of brittle intermetallic compounds, but the welding methods have the defects of harsh welding conditions, limited application, low production efficiency and the like.

The invention patent with the publication number of CN103231203B and the publication date of 2015.09.16 discloses a method for connecting aluminum and steel dissimilar materials, which adopts a cold metal transition welding method for realizing aluminum and steel dissimilar materials by combining alloy interlayer addition and mechanical inlaying, and the method utilizes a nickel cladding layer to realize aluminum/steel connection in a transition mode, but the cold metal transition welding price used in the method is high, and the precision of a nickel-based alloy upright post is difficult to control, so that the connection quality and the performance of an aluminum/steel joint are influenced.

The invention patent application with application publication number CN109158779A and application publication number 2019.01.08 discloses a laser spot welding-vacuum brazing composite welding method for aluminum alloy/high-nitrogen steel, which adopts a laser spot welding and vacuum brazing composite welding method to realize the connection of dissimilar materials of aluminum and steel, but the welding method is more complex compared with simple laser welding.

Laser welding technology is used as a welding method with high quality, high precision, low deformation, high efficiency and high speed, and laser welding has incomparable advantages compared with other welding methods, so that the laser welding technology is accepted by more and more people, and is widely applied to the fields of mechanical manufacturing, new energy automobile manufacturing, aerospace, electronic industry and the like.

The invention discloses a double-beam laser welding method and device for aluminum alloy in patent application with application publication number CN108453374A and application publication number 2018.08.28, and the method overcomes the problems of high laser reflectivity, serious burning loss of alloy elements, easy generation of air holes, unstable welding process and the like in the conventional aluminum and aluminum alloy welding process. However, this method is only suitable for welding of aluminum alloy materials, and further improvement is required for aluminum/steel materials with large variability.

The invention patent application with application publication No. CN110524107A and application publication No. 2019.12.03 discloses a method for improving the strength of an aluminum/steel dissimilar metal laser welding and brazing lap joint, which has the technical effect of improving the performance of a welded joint by directly acting a second laser beam on the surface of a steel plate, but the method is only suitable for the aluminum/steel lap joint and fails to consider the phenomenon of liquid flowing in a molten pool after the aluminum plate is melted. In summary, when welding aluminum/steel dissimilar metal materials, the dual laser beams compensate for the defect that a proper amount of intermetallic compounds are not generated at the edge of a weld due to insufficient heat input compared with the single laser beam, but fail to provide sufficient energy for liquid in a molten pool, promote the fluidity of the molten pool, reduce the generation of pores at a joint and obtain the intermetallic compounds with uniform structures. Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a welding method for welding aluminum/steel by using three-beam laser aiming at the defects in the prior art, the welding process in the welding method is simple, the deformation of welding parent metal is small, the welding seam forming is improved, the welding time is shortened, the production efficiency is improved, and the production cost is effectively saved.

The scheme is realized by the following technical measures: a welding method for aluminum/steel welding by using three-beam laser comprises the following steps:

1) selecting a welding base metal and a protective gas: the welding parent metal is an aluminum alloy plate and a steel plate, and the protective gas is argon with the purity of 99.99 percent;

2) polishing the surfaces of the aluminum alloy plate and the steel plate by using abrasive paper;

3) firstly, carrying out alkali washing and acid washing on the aluminum alloy plate after polishing treatment, then wiping the aluminum alloy plate with alcohol, and then drying the aluminum alloy plate; wiping the polished steel plate with acetone, and drying;

4) placing the aluminum alloy plate and the steel plate on a clamp for fixing;

5) welding by adopting three laser beams, namely a laser beam I, a laser beam II and a laser beam III, wherein the laser beam I is emitted by a high-power semiconductor laser, the laser beam I acts on the aluminum alloy plate, and the inclination angle of the laser beam I relative to the aluminum alloy plate is an acute angle; the laser beam II is a laser beam emitted by a single-mode fiber laser, and vertically acts on a gap between the aluminum alloy plate and the steel plate; the laser beam III is a laser beam emitted by a pulse laser, the laser beam III acts on the steel plate, and the inclination angle of the laser beam III relative to the aluminum alloy plate is an obtuse angle;

6) and (5) inspecting and analyzing after welding.

Preferably, the laser beam I acts on the aluminum alloy plate at a position 0.3-0.4 mm away from a gap between the aluminum alloy plate and the steel plate, and the inclination angle of the laser beam I relative to the aluminum alloy plate is 45 degrees.

Preferably, the laser beam III acts on the steel plate at a position 0.1-0.2 mm away from a gap between the steel plate and the aluminum alloy plate, and the inclination angle of the laser beam III relative to the aluminum alloy plate is 135 degrees.

Preferably, the protective gas I of the laser beam I forms an inclination angle of 45 degrees relative to the aluminum alloy plate, the protective gas II of the laser beam II forms an inclination angle of 90 degrees relative to the aluminum alloy plate, and the protective gas III of the laser beam III forms an inclination angle of 135 degrees relative to the aluminum alloy plate.

Preferably, the diameter of a light spot of the high-power semiconductor laser is 0.8-1.2 mm, the diameter of a light spot of the single-mode fiber laser is 0.5-1.0 mm, and the diameter of a light spot of the pulse laser is 0.1-1.0 mm.

Preferably, the wavelength of the high-power semiconductor laser is 690-980 nm; the wavelength of the single-mode fiber laser is 1060-1070 nm; the wavelength of the pulse laser is 1.064um, the pulse width is 0.1-20 ms, and the pulse current is 50-600A.

Preferably, the width of the gap between the aluminum alloy plate and the steel plate is less than 0.05 mm.

Preferably, the flow of the protective gas is 16-20L/min, the power of the high-power semiconductor laser is 3KW, the power of the single-mode fiber laser and the power of the pulse laser are 2KW, and the welding speeds of the laser beam I, the laser beam II and the laser beam III are 50-200 mm/s.

Preferably, the thickness of the aluminum alloy plate and the steel plate is 0.8-3 mm.

The beneficial effects of the invention can be known from the description of the scheme, in the welding method for welding aluminum/steel by using three-beam laser, the lasers with different modes, different wavelengths and different spot diameters are simultaneously applied to the same molten pool, and the flow mode of the molten pool is changed by adjusting the energy distribution of the three beams of laser, so that the welding process of the aluminum alloy plate and the steel plate is simple, the deformation of the base metal is small, the weld forming is improved, the welding time is shortened, the production efficiency is improved, and the production cost is effectively saved. Therefore, compared with the prior art, the invention has prominent substantive features and remarkable progress, and the beneficial effects of the implementation are also obvious.

Drawings

FIG. 1 is a perspective view of a weld according to an embodiment of the present invention.

Fig. 2 is a front view of a welding apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic top view of a weld according to an embodiment of the present invention.

In the figure, 1-steel plate, 2-weld, 3-shielding gas II, 4-laser beam II, 5-laser beam I, 6-aluminum alloy plate, 7-shielding gas I, 8-shielding gas III, 9-laser beam III, 10-gap.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the following explains the present solution by way of specific embodiments and with reference to the accompanying drawings.

A welding method for welding aluminum/steel by using three-beam laser comprises the following steps.

1) Selecting a welding base metal and a protective gas: the welding parent metal selects aluminum alloy plate 6 and steel plate 1, and preferred aluminum alloy plate 6 is 5083 aluminum alloy plate, and preferred steel plate 1 is the TWIP steel sheet, the thickness of aluminum alloy plate and steel plate is 0.8 ~ 3 mm. The protective gas is argon with the purity of 99.99%, and the flow of the protective gas is 16-20L/min.

2) The surfaces of the aluminum alloy sheet 6 and the steel sheet 1 were ground with sandpaper, and specifically, the surfaces of the aluminum alloy sheet 6 and the steel sheet 1 were ground with sandpaper of 800 mesh, 1500 mesh and 2000 mesh in this order, respectively.

3) Firstly, carrying out alkali washing and acid washing on the aluminum alloy plate 6 after polishing treatment, then wiping the aluminum alloy plate with alcohol, and then drying the aluminum alloy plate to remove an oxide film and oil stains on the surface of the aluminum alloy plate 6; and wiping the polished steel plate 1 with acetone, and drying to remove oil stains on the surface of the steel plate 1.

4) Arrange aluminium alloy plate 6 and steel sheet 1 in anchor clamps on fixed, aluminium alloy plate 6 and steel sheet 1 fix the completion back on anchor clamps, the width of gap 10 between aluminium alloy plate 6 and the steel sheet 1 is less than 0.05 mm.

5) And welding by adopting three laser beams of a laser beam I5, a laser beam II 4 and a laser beam III 9, wherein the welding speeds of the laser beam I5, the laser beam II 4 and the laser beam III 9 are all 50-200 mm/s.

Wherein, laser beam I5 is the laser beam that high power semiconductor laser sent, high power semiconductor laser's power is 3KW, high power semiconductor laser's facula diameter is 0.8 ~ 1.2mm, high power semiconductor laser's wavelength is 690 ~ 980nm, laser beam I5 acts on aluminum alloy plate 6, and laser beam I5 is the acute angle for aluminum alloy plate 6's inclination, particularly, laser beam I5 acts on aluminum alloy plate 6 0.3 ~ 0.4mm department apart from gap 10 between its and the steel sheet 1, laser beam I5 is 45 for aluminum alloy plate 6's inclination, laser beam I5's protective gas I7 is 45 for aluminum alloy plate 6's inclination.

Laser beam II 4 is the laser beam that single mode fiber laser sent, single mode fiber laser's power is 2KW, single mode fiber laser's facula diameter is 0.5 ~ 1.0mm, single mode fiber laser's wavelength is 1060 ~ 1070nm, laser beam II 4 vertical action is on the gap 10 between aluminum alloy plate 6 and the steel sheet 1 (laser beam II 4 is 90 degrees for the inclination of aluminum alloy plate 6 promptly), laser beam II 4's protective gas II 3 is 90 degrees inclination for aluminum alloy plate 6.

Laser beam III 9 is the laser beam that pulse laser sent, pulse laser's power is 2KW, pulse laser's facula diameter is 0.1 ~ 1.0mm, pulse laser's wavelength is 1.064um, and pulse width is 0.1 ~ 20ms, and pulse current is 50 ~ 600A, laser beam III 9 acts on steel sheet 1, and laser beam III 9 is the obtuse angle for aluminum alloy plate 6's inclination, particularly, laser beam III 9 acts on steel sheet 1 apart from 0.1 ~ 0.2mm department of gap 10 between its and aluminum alloy plate 6, laser beam III 9 is 135 for aluminum alloy plate 6's inclination, laser beam III 9's protective gas III 8 is 135 for aluminum alloy plate 6.

The laser beam I5 and the protective gas I7 form an inclination angle of 45 degrees relative to the aluminum alloy plate 6, the heating diameter of the laser beam I5 can be maximized through the inclination angle, the melting area of the aluminum alloy plate 6 is expanded, and good gap filling capacity is obtained. The laser beam III 9 and the protective gas III 8 form an inclination angle of 135 degrees relative to the aluminum alloy plate 6, and the preheating range of the steel plate 1 is expanded by maximizing the heating diameter of the laser beam III 9 through the inclination angle, so that the deformation amount is reduced. The laser beam II 4 and the protective gas II 3 form an inclination angle of 90 degrees relative to the aluminum alloy plate 6, the inclination angle is favorable for promoting the liquidity of liquid in a molten pool, gas in the molten pool is discharged, and the generation of pores at the welding seam 2 is reduced. If the inclination angle of the laser beam I5 and the shielding gas I7 relative to the aluminum alloy plate 6 is more than 45 degrees or less than 45 degrees, the inclination angle of the laser beam II 4 and the shielding gas II 3 relative to the aluminum alloy plate 6 is 90 degrees or less than 90 degrees, and the inclination angle of the laser beam III 9 and the shielding gas III 8 relative to the aluminum alloy plate 6 is more than 135 degrees or less than 135 degrees, the strength and the formability of the welding seam 2 are reduced.

When single-beam laser and double-beam laser welding are adopted, the establishment of the key hole is difficult, and the stability is not easy to maintain. According to the invention, two additional laser beams II 4 and III 9 with different modes, different wavelengths and different spot diameters are respectively and directly acted on the aluminum alloy plate 6 and the steel plate 1, so that the size of the key hole can be increased, the key hole is not easy to close, gas is discharged, the cooling rate is reduced, and the generation of air holes and welding cracks is reduced. Meanwhile, as the welding process is more stable and the splashing amount is reduced, the surface forming of the welding seam 2 obtained by welding aluminum/steel dissimilar metal by three beams is also obviously superior to that of a single beam and a double beam.

6) Postweld inspection and analysis, postweld inspection of weld 2 formation, including: and (3) detecting the hardness and tensile property of the weld joint 2 according to the continuity of the surface weld joint 2 and whether the defects of key holes, welding penetration and the like exist.

The invention adopts a method of simultaneously welding three beams of laser, strictly controls the laser angle and prevents the generation of welding defects in the welding process due to the influence of the laser incident angle. The welding is carried out under the welding method, the defects of undercut, welding through, unwelded and the like are avoided, the grain size and the intermetallic compound meet the requirements, and the mechanical property of the welded part can be found to meet the requirements according to hardness detection and tensile property detection.

Technical features not described in the present invention can be implemented by the prior art, and are not described in detail herein. The present invention is not limited to the above-described embodiments, and variations, modifications, additions and substitutions which are within the spirit of the invention and the scope of the invention may be made by those of ordinary skill in the art are also within the scope of the invention.