Laser welding method

Abstract

The invention relates to a laser welding method. According to the welding method, a first welding wire and a second welding wire are used for conducting laser welding at the same time, the first welding wire is a gas shielded welding wire, and the second welding wire is a gas shielded welding wire or a NiCr alloy welding wire. According to the welding method for laser double-wire welding, under the action of high-energy-density laser, molten metal is rapidly melted into a gap to form a welding seam molten pool, meanwhile, molten metal in a welding seam can be rapidly cooled and solidified, thermal deformation is small, the welding seam is uniform and compact, the surface quality is good, and the risk of cracking caused by stress concentration can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of laser welding. Specifically, the present invention relates to a laser welding method. Background Art

[0002] With the rapid development of the domestic new energy vehicle industry, in order to better ensure the driving safety of vehicles, higher requirements are put forward for the welding process of automotive body steel. The thickness range of steel parts on vehicles is about 1.0 - 5.0 mm, and the welding methods include various welding methods such as butt welding, lap welding, fillet welding, plug welding, spot welding, etc. Laser autogenous welding and laser wire filling welding are widely used in the butt welding of steel; argon arc welding is widely used in lap welding, fillet welding, plug welding, etc.

[0003] There are some deficiencies in the existing welding methods. For example, the deficiencies of argon arc welding technology are as follows:

[0004] 1. When welding, the generated welding fume is relatively large, and the welding slag spatter generated during welding has a greater impact on the surface of the parts, affecting the appearance of the parts and increasing the subsequent grinding process;

[0005] 2. To meet the welding technical requirements such as lap welding and fillet welding of steel plates with relatively high thicknesses, a relatively large current is used, resulting in a relatively large heat - affected zone of the weld. When applied to the welding of hot - formed parts, it increases the thermal deformation and internal stress during the welding process, and increases the risk of cracking due to stress concentration after the hot - formed parts are welded and installed on the vehicle.

[0006] The deficiencies of laser wire filling welding technology are as follows:

[0007] 1. It has high requirements for the adaptability of the butt - welded plate gap, welding equipment, and tooling fixtures. The welding speed is slow, and defects such as leakage holes and welding deviation are easily formed during welding;

[0008] 2. When the laser wire filling welding technology is applied to the lap welding of plates with a thickness of 3 mm or more, even using a larger - diameter welding wire and a higher - power laser cannot better meet the lap - welding technical requirements.

[0009] Therefore, there is a need in the art for a welding technology that can produce good surface quality and avoid cracking of components due to stress concentration subsequently. Summary of the Invention

[0010] The present invention aims to provide a new laser welding method, which can solve one or more problems in the existing ones.

[0011] According to the first aspect of the present invention, there is provided a laser welding method, characterized in that laser welding is simultaneously performed using a first welding wire and a second welding wire, the first welding wire is a gas - shielded welding wire, and the second welding wire is a gas - shielded welding wire or a NiCr alloy welding wire.

[0012] The mass percentage ratio of chemical elements of the gas-shielded welding wire is as follows: C: 0.06 - 0.15%, Mn: 1.40 - 1.85%, Si: 0.7 - 1.15%, S: 0.001 - 0.025%, P: 0.001 - 0.025%, Cu: 0.01 - 0.2%, Cr: 0.001 - 0.05%, Ni: 0.001 - 0.015%, Mo: 0.001 - 0.01%, V: 0.0005 - 0.003%, Fe: the balance,

[0013] The mass percentage ratio of chemical elements of the NiCr alloy welding wire is as follows: C: 0.05 - 0.1%, Mn: 0.1 - 0.4%, Si: 0.001 - 0.009%, S: 0.001 - 0.04%, P: 0.001 - 0.03%, Cr: 20 - 24%, Mo: 8 - 10%, Ti: 0.2 - 0.6%, Ni: the balance.

[0014] According to the second aspect of the present invention, there is provided a component, characterized in that it includes a weld formed by the above laser welding method.

[0015] The present invention has the following beneficial effects:

[0016] Under the action of high-energy density laser, the laser welding method of the present invention quickly melts into the gap to form a weld pool. At the same time, the molten metal in the weld can quickly cool and solidify, with small thermal deformation, uniform and dense welds, and good surface quality, which can reduce the risk of cracking caused by stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described in conjunction with the accompanying drawings to enable those skilled in the art to better understand the features and advantages of the present invention, where:

[0018] Figure 1 is a schematic diagram of the laser double-wire welding equipment used in the embodiment.

[0019] Figure 2 is a photo of two 3.0 mm thick plates after laser butt welding in Example 1.

[0020] Figure 3 is a photo of two 3.0 mm thick plates after argon arc welding in Comparative Example 1.

[0021] Figure 4 is a photo of two 3.0 mm thick plates after laser lap welding in Example 2.

[0022] Figure 5 is Figure 4 the metallographic diagram of

[0023] Figure 6It is the metallographic diagram of the tack weld in Example 3.

[0024] Figure 7 It is the metallographic diagram of the tack weld in Example 4.

[0025] Figure 8 It is the metallographic diagram of the tack weld in Example 5. Detailed implementation manners

[0026] In the following, various aspects of the present invention, as well as further objects, features and advantages will be more comprehensively embodied in combination with some specific implementation manners.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. When the definition of a term in this specification conflicts with the meaning commonly understood by those skilled in the art to which the present invention pertains, the definition described herein shall apply.

[0028] In the following and unless otherwise specified, the upper and lower limits of a numerical range are included in the range, especially in the expressions "between... and..." and "... to...".

[0029] In this application, the term "comprising / including" shall be interpreted to cover all specifically mentioned features as well as optional, additional, unspecified features. As used herein, the use of the term "comprising / including" also discloses embodiments in which there are no features other than the specifically mentioned features (i.e., "consisting of...").

[0030] In this application, the use of expressions such as "preferably", "advantageously" and the like means that the features following them bring benefits for the purpose of the present invention (especially one or more of the properties such as the surface quality of the weld, the penetration depth, the mechanical properties of the finished product, etc.).

[0031] Unless otherwise specified, all numerical values representing amounts of components, etc. used in the specification and claims should be understood to be modified by the term "about". Therefore, unless otherwise indicated, the numerical values and parameters described herein are approximate values that can be varied as required according to the desired purpose.

[0032] Laser welding method

[0033] The present invention provides a laser welding method, characterized in that laser welding is carried out simultaneously using a first welding wire and a second welding wire, the first welding wire is a gas shielded welding wire, and the second welding wire is a gas shielded welding wire or a NiCr alloy welding wire.

[0034] The mass percentage ratio of chemical elements of the gas-shielded welding wire is as follows: C: 0.06 - 0.15%, Mn: 1.40 - 1.85%, Si: 0.7 - 1.15%, S: 0.001 - 0.025%, P: 0.001 - 0.025%, Cu: 0.01 - 0.2%, Cr: 0.001 - 0.05%, Ni: 0.001 - 0.015%, Mo: 0.001 - 0.01%, V: 0.0005 - 0.003%, Fe: the balance,

[0035] The mass percentage ratio of chemical elements of the NiCr alloy welding wire is as follows: C: 0.05 - 0.1%, Mn: 0.1 - 0.4%, Si: 0.001 - 0.009%, S: 0.001 - 0.04%, P: 0.001 - 0.03%, Cr: 20 - 24%, Mo: 8 - 10%, Ti: 0.2 - 0.6%, Ni: the balance.

[0036] In the laser welding method of the present invention, the first welding wire serves as the main filler metal, and the second welding wire is used to improve the fluidity of the weld pool. The configuration of the double welding wires can provide a larger weld pool according to the welding requirements, enhancing the welding depth and width, which is helpful for processing thicker steel or applications that require larger welding joints. During laser double-wire welding, according to the pre-set welding path, the front first welding wire melts and quickly drops into the gap, and the subsequent second welding wire follows closely and melts into the weld gap to form a weld pool, improving the weld composition and performance without forming leakage holes; secondly, since the two welding wires promote the formation of the weld pool simultaneously, there is more welding wire filler in the weld gap, having a better gap tolerance and reducing the requirements for integrated equipment such as jigs and tooling.

[0037] Preferably, the diameters of the first welding wire and the second welding wire are independently 0.6 - 2 mm.

[0038] By matching welding wires with different diameters, it is possible to weld both thick and thin aluminum-silicon coatings, greatly reducing the cost of customized welding wires.

[0039] Preferably, the laser power is 3000 - 8000 W, and more preferably, the laser power is 3000 - 6000 W.

[0040] Preferably, the welding speed is 10 - 40 mm / s.

[0041] Preferably, the wire feeding speed is 1000 - 3000 mm / min.

[0042] By regulating process parameters such as welding speed, wire feeding speed, and power, the modification and improvement of the weld composition are achieved, thereby enhancing the overall quality of the weld.

[0043] In some embodiments, the material to be welded is aluminum-silicon coated steel, the first welding wire is a gas shielded welding wire, and the second welding wire is a NiCr alloy welding wire.

[0044] Through the synergistic effect of two welding wires with different materials, adjusting the welding process parameters can improve the performance of the weld seam, reduce the requirements for welding tooling fixtures and gaps, and eliminate the need to customize welding wires of specific materials, which will greatly reduce the development cost.

[0045] For the welding of steel with an aluminum-silicon coating on the surface, during welding, the Al element in the surface aluminum-silicon coating melts into the weld pool, resulting in reduced stability of the weld pool, formation of pores, increased brittleness, thereby reducing the mechanical properties of the weld seam and posing a significant safety risk. However, as an important solid solution strengthening element, Cr reduces the stacking fault energy of the solid solution, thereby enhancing the strength of the weld seam. As an important austenite stabilizing element, increasing the content of Ni element in the weld seam can reduce the content of δ-ferrite, improving the toughness and plasticity of the weld seam. At the same time, due to the relatively high content of Mo element in the NiCr alloy welding wire, it can form a stable solid solution with Fe and C, effectively enhancing the wear resistance of the weld seam, increasing the weld seam strength, and improving the overall quality of the weld seam.

[0046] Under the synergistic effect of the double welding wires, by adjusting parameters such as welding speed, wire feeding speed, and power, stable control of the elemental composition in the weld seam can be achieved without further treatment of the parts to be welded, which will effectively integrate the influence of the Al element in the aluminum-silicon coating melting into the weld pool and improve the weld seam performance.

[0047] In some embodiments, the material to be welded is uncoated steel, and both the first welding wire and the second welding wire are gas shielded welding wires.

[0048] Preferably, the mass percentage distribution of chemical elements of the gas shielded welding wire is as follows:

[0049] C: 0.06 - 0.12%, Mn: 1.4 - 1.6%, Si: 0.7 - 1.0%, S: 0.005 - 0.02%, P: 0.005 - 0.02%, Cu: 0.05 - 0.2%, Cr: 0.01 - 0.05%, Ni: 0.005 - 0.015%, Mo: 0.005 - 0.01%, V: 0.001 - 0.0025%, Fe: balance.

[0050] More preferably, the mass percentage distribution of chemical elements of the gas shielded welding wire is as follows:

[0051] C: 0.06 - 0.1%, Mn: 1.45 - 1.55%, Si: 0.75 - 0.95%, S: 0.01 - 0.015%, P: 0.01 - 0.02%, Cu: 0.08 - 0.15%, Cr: 0.01 - 0.03%, Ni: 0.008 - 0.012%, Mo: 0.007 - 0.01%, V: 0.001 - 0.002%, Fe: the balance.

[0052] Still more preferably, the mass percentage ratio of chemical elements of the gas shielded welding wire is:

[0053] C: 0.065 - 0.085%, Mn: 1.45 - 1.55%, Si: 0.8 - 0.95%, S: 0.01 - 0.015%, P: 0.01 - 0.02%, Cu: 0.1 - 0.15%, Cr: 0.01 - 0.03%, Ni: 0.008 - 0.012%, Mo: 0.007 - 0.009%, V: 0.001 - 0.002%, Fe: the balance.

[0054] In some embodiments, the mass percentage ratio of chemical elements of the gas shielded welding wire is: C: 0.075%, Mn: 1.49%, Si: 0.9%, S: 0.012%, P: 0.015%, Cu: 0.12%, Cr: 0.02%, Ni: 0.01%, Mo: 0.008%, V: 0.001%, Fe: the balance.

[0055] Preferably, the mass percentage ratio of chemical elements of the NiCr alloy welding wire is:

[0056] C: 0.05 - 0.08%, Mn: 0.1 - 0.3%, Si: 0.003 - 0.009%, S: 0.01 - 0.03%, P: 0.01 - 0.025%, Cr: 20.5 - 23%, Mo: 8 - 9.5%, Ti: 0.2 - 0.5%, Ni: the balance.

[0057] More preferably, the mass percentage ratio of chemical elements of the NiCr alloy welding wire is:

[0058] C: 0.05 - 0.07%, Mn: 0.15 - 0.25%, Si: 0.004 - 0.008%, S: 0.01 - 0.02%, P: 0.01 - 0.02%, Cr: 21 - 22.5%, Mo: 8.5 - 9.3%, Ti: 0.25 - 0.45%, Ni: the balance.

[0059] Still more preferably, the mass percentage ratio of chemical elements of the NiCr alloy welding wire is:

[0060] C: 0.05 - 0.06%, Mn: 0.17 - 0.23%, Si: 0.005 - 0.007%, S: 0.01 - 0.015%, P: 0.01 - 0.02%, Cr: 21.3 - 22.3%, Mo: 8.7 - 9.2%, Ti: 0.3 - 0.4%, Ni: the balance.

[0061] In some embodiments, the mass percentage ratios of chemical elements of the NiCr alloy welding wire are: C: 0.054%, Mn: 0.2%, Si: 0.006%, S: 0.01%, P: 0.01%, Cr: 21.8%, Ni: the balance, Mo: 9.05%, Ti: 0.35%, Ni: the balance.

[0062] The NiCr alloy welding wire increases the contents of Ni, Cr, and Mo elements in the weld, effectively synthesizes the influence of the A1 element melted into the weld during welding on the weld strength, effectively improves the welding efficiency, reduces the welding requirements, and improves the overall performance of the weld.

[0063] The laser welding method of the present invention is applicable to welding steel materials that have undergone different treatments, whether they are cold stamping parts formed by cold-rolled steel or hot-rolled steel, or hot-formed parts that have undergone quenching and stamping processes.

[0064] Due to the high energy density of the laser, the heat-affected zone of the weld is small. When welding hot-formed parts on an automobile, it can effectively reduce the thermal deformation and internal stress during the welding process, reduce the risk of cracking caused by stress concentration after the hot-formed parts are welded and installed on the vehicle. At the same time, it can improve the dimensional accuracy and shape stability of the welded parts, provide more precise welding control, and reduce the influence of manual operation on the welding quality.

[0065] The laser welding method of the present invention utilizes the synergistic advantages of double welding wires and is applicable to various welding methods of steel materials, such as butt welding, lap welding, fillet welding, plug welding, etc. During the butt welding of steel materials, the double welding wires can provide a more uniform distribution of molten metal during the welding process, improve the quality and consistency of the weld, help improve the strength and durability of the welded joint, reduce the probability of defects such as leakage holes and welding deviation, and have a good gap tolerance, meeting the technical requirements of various welding methods.

[0066] When using the laser welding method of the present invention for lap welding, weld seam properties far exceeding industry standards can be obtained. For example, the highest technical requirements for lap welding in the industry are as follows: for upper and lower plate lap welding, the penetration depth of the lower plate needs to exceed 20% of the thickness of the thinnest sheet material, and the minimum common weld thickness needs to exceed 70% of the thickness of the thinnest sheet material; the general requirements are: for upper and lower plate lap welding, the penetration depth of the lower plate needs to exceed 10% of the thickness of the thinnest sheet material, and the minimum common weld thickness needs to exceed 70% of the thickness of the thinnest sheet material. Taking the lap welding of 4mm and 3mm as an example, the minimum required penetration depth is ≥0.3mm, and the minimum common weld thickness is ≥2.1mm; the most stringent technical requirement for penetration depth is ≥0.6mm, and the minimum common weld thickness is ≥2.1mm.

[0067] The laser welding method of the present invention solves the problems of existing laser filler wire welding, such as having gaps in the welded plates, high requirements for the adaptability of welding equipment and tooling fixtures, slow welding speed, extremely easy formation of leakage holes and welding deviation during welding, and being inapplicable to the welding of high-thickness steel materials. For the welding of aluminum-silicon coated steel plates with a certain thickness on the surface, the strength of the weld is reduced due to the melting of A1 elements into the weld pool.

[0068] Parts

[0069] The present invention provides a component, characterized in that it includes a weld seam formed by the above laser welding method.

[0070] The component can be, for example, cold stamping parts and hot forming parts formed from cold-rolled steel and hot-rolled steel.

[0071] The hot forming part can be one that has undergone quenching and stamping processes.

[0072] The steel can be uncoated or coated, such as aluminum-silicon coated.

[0073] In some embodiments, the steel is uncoated steel, which includes a weld seam formed by using two gas shielded welding wires by the laser welding method. The obtained weld seam has good surface quality and improved weld strength and / or penetration depth.

[0074] In some embodiments, the steel is steel with an aluminum-silicon coating, which includes a weld seam formed by using a gas shielded welding wire and a NiCr alloy welding wire by the laser welding method. The obtained weld seam has higher weld strength and / or penetration depth.

[0075] Examples

[0076] Hereinafter, the concept and technical effects of the present invention will be further described in conjunction with examples and drawings, so that those skilled in the art can fully understand the purpose, features and effects of the present invention. It is not difficult for those skilled in the art to understand that the examples here are only for illustrative purposes, and the scope of the present invention is not limited thereto.

[0077] Equipment Used

[0078] Figure 1 Figure 1 shows a schematic diagram of the laser double-wire welding equipment used in the embodiment. On the left is the laser welding equipment system, and in the middle part, two wire coils are integrated on the automation equipment to weld the parts on the fixture on the right. The laser double-wire welding equipment mainly includes a high-energy laser source, an optical system, a workbench, and automation equipment. Among them, the laser source mainly provides high-power laser, and the optical system is mainly composed of a collimating mirror, a focusing mirror, etc. Its function is to collimate and focus the laser beam. The collimating mirror is used to reduce the divergence angle of the laser beam, and the focusing mirror is used to focus the laser beam on the workpiece surface.

[0079] Example 1 and Comparative Example 1

[0080] In Example 1, two uncoated steel plates with a length and width of 200×100 mm and a thickness of 3.0 mm were aligned and butt-welded. The part gap was 1.2 mm. Two gas-shielded welding wires with a diameter of 1.6 mm were used. The laser power was 4800 W, the welding speed was 15 mm / s, and the wire feeding speed was 1800 mm / min.

[0081] In Comparative Example 1, welding was carried out with reference to the same steps as in Example 1, and the only difference was that the argon arc welding process was adopted.

[0082] The mass percentage distribution ratio of chemical elements of the used gas-shielded welding wire is as follows: C: 0.06%, Mn: 1.4%, Si: 0.8%, S: 0.025%, P: 0.025%, Cu: 0.2%, Cr: 0.05%, Ni: 0.015%, Mo: 0.01%, V: 0.003%, Fe: the balance.

[0083] Figure 2 Figure 2 shows the weld seam after laser welding in Example 1. From Figure 2 It can be seen that the surface quality of the weld seam is good after welding, and there is no obvious spatter around the weld seam.

[0084] Figure 3 Figure 3 shows the argon arc weld seam in Comparative Example 1.

[0085] By comparing the surfaces of the weld seams, it is found that the surface quality of the weld seam after laser welding is better than that of the argon arc weld seam.

[0086] Tensile tests were carried out on samples of the two welded products (the test standard is GB / T 2651-2023), and the test results are summarized in Table 1.

[0087] Table 1

[0088]

[0089] As can be seen from Table 1, for the laser twin-wire welding of tailor-welded hot-formed parts with a material thickness of 3 mm, the tensile strength and yield strength of the laser twin-wire welded seams are significantly higher than those of the TIG welded seams.

[0090] Example 2

[0091] Two uncoated steel plates with a length and width of 200×100 mm and a material thickness of 3.0 mm were lap welded. Two gas-shielded welding wires with a diameter of 1.6 mm were used. The laser power was 4800 W, the welding speed was 15 mm / s, and the wire feeding speed was 2000 mm / min.

[0092] The mass percentage distribution of chemical elements of the used gas-shielded welding wire is as follows: C: 0.15%, Mn: 1.85%, Si: 1.15%, S: 0.015%, P: 0.02%, Cu: 0.15%, Cr: 0.03%, Ni: 0.012%, Mo: 0.009%, V: 0.002%, Fe: balance.

[0093] Figure 4 The welded seam after laser welding is shown in. From Figure 4 it can be seen that the surface quality of the lap-welded seam is high, and there is no obvious spatter at the edge of the welded seam.

[0094] A stereomicroscope was used to detect the penetration depth of the welded seam. Figure 5 The metallographic diagram of the lap-welded seam taken by a metallurgical microscope is shown in. Through detection, it is found that the penetration depth of the lower plate wire of the lap welding is 2.0 mm and the minimum common welded seam thickness is 2.9 mm, exceeding the lap welding technical requirements in the industry.

[0095] Example 3

[0096] Two uncoated steel plates with a length and width of 200×100 mm and material thicknesses of 3.5 mm and 3.0 mm were quenched and stamped to obtain hot-formed parts. The two steel plates were lap welded. Two gas-shielded welding wires with a diameter of 1.6 mm were used. The laser power was 5000 W, the welding speed was 12 mm / s, and the wire feeding speed was 2000 mm / min.

[0097] The mass percentage distribution of chemical elements of the used gas-shielded welding wire is as follows: C: 0.075%, Mn: 1.49%, Si: 0.9%, S: 0.012%, P: 0.015%, Cu: 0.12%, Cr: 0.02%, Ni: 0.01%, Mo: 0.008%, V: 0.001%, Fe: balance.

[0098] The surface quality of the lap-welded seam is high, and there is no obvious spatter at the edge of the welded seam.

[0099] A stereomicroscope was used to detect the penetration depth of the welded seam. Figure 6The metallographic diagram of the overlap weld obtained by a metallographic microscope is shown. Through detection, it is found that the penetration depth of the welding wire into the lower plate of the overlap weld is 1.842 mm and the minimum common weld thickness is 3.224 mm, exceeding the technical requirements of the overlap welding in the industry.

[0100] Example 4

[0101] Overlap welding is carried out on steel parts with a surface without coating and material thicknesses of 4 mm and 3 mm. Two gas shielded welding wires with a diameter of 1.6 mm are used for welding. The laser power is 5500 W, the welding speed is 10 mm / s, and the wire feeding speed is 1800 mm / min.

[0102] The mass percentage distribution of chemical elements of the used gas shielded welding wire is as follows: C: 0.07%, Mn: 1.45%, Si: 0.75%, S: 0.01%, P: 0.01%, Cu: 0.08%, Cr: 0.01%, Ni: 0.008%, Mo: 0.007%, V: 0.001%, Fe: the balance.

[0103] The surface quality of the overlap weld is relatively high, and there is no obvious spatter at the weld edge.

[0104] A stereomicroscope is used for detecting the weld penetration. Figure 7 The metallographic diagram of the overlap weld obtained by a metallographic microscope is shown. Through detection, it is found that the penetration depth of the welding wire into the lower plate of the overlap weld is 1.686 mm and the minimum common weld thickness is 4.037 mm, exceeding the technical requirements of the overlap welding in the industry.

[0105] Example 5

[0106] Using the same conditions as in Example 4, overlap welding is carried out on steel parts with a surface without coating and material thicknesses of 5 mm and 3 mm.

[0107] The surface quality of the overlap weld is relatively high, and there is no obvious spatter at the weld edge.

[0108] A stereomicroscope is used for detecting the weld penetration. Figure 8 The metallographic diagram of the overlap weld obtained by a metallographic microscope is shown. Through detection, it is found that the penetration depth of the welding wire into the lower plate of the overlap weld is 1.954 mm and the minimum common weld thickness is 3.889 mm, exceeding the technical requirements of the overlap welding in the industry.

[0109] Comparative Examples 2 - 6

[0110] The thin-plated steel sheets with a surface aluminum-silicon coating thickness of 10 - 30 μm and a material thickness of 1 - 2 mm are butt-welded, and laser double-wire welding is carried out using two gas-shielded welding wires with the same composition and a diameter of 0.8 mm; the laser power is 3000 - 6000 W, the welding speed is 10 - 40 mm / s, and the wire feeding speed is 2500 - 4000 mm / min. The specific parameters are summarized in Table 2.

[0111] The mass percentage distribution of chemical elements of the used gas-shielded welding wire is as follows: C: 0.058%, Mn: 1.44%, Si: 0.73%, S: 0.012%, P: 0.009%, Cu: 0.12%, Ti: 0.003%, and the balance is Fe.

[0112] The obtained welded products are subjected to hot forming quenching, and then samples are taken for tensile testing. The test results are summarized in Table 2.

[0113] Table 2

[0114]

[0115] The test results show that the strength is relatively low and the fracture occurs in the middle of the weld, indicating that the weld strength is lower than that of the base metal.

[0116] Examples 6 - 10

[0117] The thin-plated steel sheets with a surface aluminum-silicon coating thickness of 10 - 30 μm and a material thickness of 1 - 2 mm are butt-welded, and laser double-wire welding is carried out using two welding wires with a diameter of 0.8 mm; one is a gas-shielded welding wire and the other is a NiCr alloy welding wire. The laser power is 3000 - 6000 W, the welding speed is 10 - 40 mm / s, and the wire feeding speed is 2500 - 4000 mm / min. The specific parameters are summarized in Table 3.

[0118] The mass percentage distribution of chemical elements of the used gas-shielded welding wire is as follows: C: 0.075%, Mn: 1.49%, Si: 0.9%, S: 0.012%, P: 0.015%, Cu: 0.12%, Cr: 0.02%, Ni: 0.01%, Mo: 0.008%, V: 0.001%, and the balance is Fe.

[0119] The mass percentage distribution of chemical elements of the used NiCr alloy welding wire is as follows: C: 0.054%, Mn: 0.2%, Si: 0.006%, S: 0.01%, P: 0.01%, Cr: 21.8%, Mo: 9.05%, Ti: 0.35%, and the balance is Ni.

[0120] The weld forming quality is good, without defects such as leakage holes and welding deviation.

[0121] The obtained welded products are subjected to hot forming quenching, and then samples are taken for tensile testing. The test results are summarized in Table 3.

[0122] Table 3

[0123]

[0124] The fracture in the tensile test occurs in the base metal, indicating that the weld strength is higher than that of the base metal. In addition, by using two different types of welding wires and regulating the welding speed, power, and wire feeding speed, stable regulation of the melting of Ni, Cr, and Mo elements in the NiCr alloy welding wire into the weld can be achieved, which can effectively improve the toughness of the weld and enhance the weld strength at the same time.

[0125] Comparative Examples 7 - 11

[0126] For the laser dual - wire welding of thick - coated steel sheets with an aluminum - silicon coating thickness of more than 30μm and a material thickness of 1 - 2mm, a gas - shielded welding wire with a diameter of 0.8mm and another 316L stainless - steel welding wire are used; the laser power is 3000 - 6000W, the welding speed is 10 - 20mm / s, and the wire feeding speed is 2000 - 3000mm / min. The specific parameters are summarized in Table 4.

[0127] The mass percentage distribution of chemical elements in the used gas - shielded welding wire is as follows: C: 0.058%, Mn: 1.44%, Si: 0.73%, S: 0.012%, P: 0.009%, Cu: 0.12%, Ti: 0.003%, and the balance is Fe.

[0128] The mass percentage distribution of chemical elements in the used 316L stainless - steel welding wire is as follows: C: 0.041%, Mn: 16.85%, Si: 0.42%, S: 0.001%, P: 0.022%, Cu: 0.86%, Cr: 12.69%, Ni: 1.56%, Mo: 0.03%, Ti: 0.31%, and the balance is Fe.

[0129] The obtained welded products are subjected to hot forming quenching, and then samples are taken for tensile testing. The test results are summarized in Table 4.

[0130] Table 4

[0131]

[0132] The test results show that the strength is low and the fracture occurs in the middle of the weld, indicating that the weld strength is lower than that of the base metal.

[0133] Examples 11 - 15

[0134] Thick-coated steel plates with a surface aluminum-silicon coating thickness of more than 30 μm and a material thickness of 1-2 mm were welded using a gas shielded welding wire with a diameter of 0.8 mm and a NiCr alloy welding wire with a diameter of 1.2 mm. The laser power was 3000-6000 W, the welding speed was 10-20 mm / s, and the wire feeding speed was 2000-3000 mm / min. The specific parameters are summarized in Table 5.

[0135] The mass percentage ratio of the chemical elements of the gas shielded welding wire used is: C: 0.075%, Mn: 1.49%, Si: 0.9%, S: 0.012%, P: 0.015%, Cu: 0.12%, Cr: 0.02%, Ni: 0.01%, Mo: 0.008%, V: 0.001%, Fe: balance.

[0136] The chemical element mass percentage ratio of the NiCr alloy welding wire used is: C: 0.05%, Mn: 0.1%, Si: 0.009%, S: 0.04%, P: 0.03%, Cr: 20%, Mo: 8%, Ti: 0.2%, Ni: balance.

[0137] The weld forming quality is good, without defects such as leaks and weld deviations.

[0138] The obtained welded products were hot formed and quenched, and then samples were taken for tensile testing. The test results are summarized in Table 5.

[0139] Table 5

[0140]

[0141] The tensile test showed fracture in the parent material, indicating that the weld was stronger than the parent material. Furthermore, by using two different welding wires and adjusting the welding speed, power, and wire feed rate, the incorporation of Ni, Cr, and Mo elements from the NiCr alloy wire into the weld can be stably controlled, effectively improving both weld toughness and strength.

[0142] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily devise other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the claims of the present invention.

Claims

1. A laser welding method, characterized in that, Laser welding is carried out simultaneously using a first welding wire and a second welding wire. The first welding wire is a gas-shielded welding wire, and the second welding wire is a gas-shielded welding wire or a NiCr alloy welding wire. The mass percentage ratio of chemical elements of the gas-shielded welding wire is as follows: C: 0.06 - 0.15%, Mn: 1.40 - 1.85%, Si: 0.7 - 1.15%, S: 0.001 - 0.025%, P: 0.001 - 0.025%, Cu: 0.01 - 0.2%, Cr: 0.001 - 0.05%, Ni: 0.001 - 0.015%, Mo: 0.001 - 0.01%, V: 0.0005 - 0.003%, Fe: the balance. The mass percentage ratio of chemical elements of the NiCr alloy welding wire is as follows: C: 0.05 - 0.1%, Mn: 0.1 - 0.4%, Si: 0.001 - 0.009%, S: 0.001 - 0.04%, P: 0.001 - 0.03%, Cr: 20 - 24%, Mo: 8 - 10%, Ti: 0.2 - 0.6%, Ni: the balance.

2. A laser welding method according to claim 1, wherein the diameters of the first welding wire and the second welding wire are independently 0.6-2 mm, the laser power is 3000-8000 W, the welding speed is 10-40 mm / s, and the wire feeding speed is 1000-3000 mm / min.

3. A laser welding method according to claim 1 or 2, wherein the material to be welded is aluminum-silicon coated steel, the first welding wire is a gas-shielded welding wire, and the second welding wire is a NiCr alloy welding wire.

4. A welding method of laser twin-wire welding according to claim 1 or 2, wherein the material to be welded is uncoated steel, and both the first welding wire and the second welding wire are gas-shielded welding wires.

5. A laser welding method according to claim 1 or 2, wherein the mass percentage ratio of chemical elements of the gas-shielded welding wire is as follows: C: 0.06 - 0.12%, Mn: 1.4 - 1.6%, Si: 0.7 - 1.0%, S: 0.005 - 0.02%, P: 0.005 - 0.02%, Cu: 0.05 - 0.2%, Cr: 0.01 - 0.05%, Ni: 0.005 - 0.015%, Mo: 0.005 - 0.01%, V: 0.001 - 0.0025%, Fe: the balance.

6. A laser welding method according to claim 1 or 2, wherein the mass percentage ratio of chemical elements of the gas-shielded welding wire is as follows: C: 0.06 - 0.1%, Mn: 1.45 - 1.55%, Si: 0.75 - 0.95%, S: 0.01 - 0.015%, P: 0.01 - 0.02%, Cu: 0.08 - 0.15%, Cr: 0.01 - 0.03%, Ni: 0.008 - 0.012%, Mo: 0.007 - 0.01%, V: 0.001 - 0.002%, Fe: the balance.

7. A laser welding method according to claim 1 or 2, characterized in that the mass percentage ratio of chemical elements of the NiCr alloy welding wire is as follows: C: 0.05 - 0.08%, Mn: 0.1 - 0.3%, Si: 0.003 - 0.009%, S: 0.01 - 0.03%, P: 0.01 - 0.025%, Cr: 20.5 - 23%, Mo: 8 - 9.5%, Ti: 0.2 - 0.5%, Ni: the balance.

8. A laser welding method according to claim 1 or 2, characterized in that the mass percentage ratio of chemical elements of the NiCr alloy welding wire is as follows: C: 0.05 - 0.07%, Mn: 0.15 - 0.25%, Si: 0.004 - 0.008%, S: 0.01 - 0.02%, P: 0.01 - 0.02%, Cr: 21 - 22.5%, Mo: 8.5 - 9.3%, Ti: 0.25 - 0.45%, Ni: the balance.

9. A component, characterized in that, including a weld formed by the laser welding method according to any one of claims 1 - 8.

10. The component according to claim 9, characterized in that, selected from cold-rolled steel, cold stamping parts and hot forming parts formed by hot-rolled steel.

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