A laser-arc hybrid welding method for medium-thickness steel plate without a groove

Abstract

The application discloses a kind of medium thickness steel plate no-bevel laser-arc composite welding method, it is related to metal welding technical field, comprising the following steps: welding metal pretreatment;Welding metal group is to;Preheating dehumidification;With I type bevel form, laser guide or arc guide mode is carried out welding, laser and weld angle 70 °~90 °, laser power 1kW-20kW, arc power 2kW-15kW, welding speed 0.5m / min-3m / min;The application can significantly improve the welding efficiency of medium plate penetration butt joint and penetration angle joint by adopting I type bevel form combined with specific welding parameters, reduce the consumption of welding wire, welding deformation is small, weld forming is good, and the mechanical properties of weld metal meet relevant national standards.

Description

Technical Field

[0001] This invention relates to the field of metal welding technology, specifically to a laser-arc hybrid welding method for medium-thickness steel plates without beveling. Background Technology

[0002] Currently, in steel structure processing and manufacturing, welding of medium and thick plates is common. Long straight bevel welds or bevel fillet welds generally adopt traditional arc welding technology. The main problems with traditional welding methods are: 1) The process is cumbersome, requiring beveling; 2) Quality control is difficult: the root must be cleaned before welding the reverse side of butt or full penetration welds to ensure penetration; 3) The welded parts have large thermal deformation, and the weld quality depends on experience and parameters.

[0003] Lasers, as a high-energy-density heat source, offer unique advantages in welding: high welding speed, low heat input, minimal weld deformation, narrow heat-affected zone, fewer welding defects, and ease of obtaining high-quality welds, making them considered the most advanced welding technology currently available. However, they have low adaptability to the assembly gap and misalignment of the weld metals, and a narrow welding process window. Laser-arc hybrid welding combines the advantages of both lasers and arcs, overcoming their respective shortcomings. The metal ions generated by the laser incident on the metal are attracted by the arc, increasing the efficiency of laser energy transfer to the weld metal, reducing the resistance of the arc channel, improving the energy utilization rate of the arc, increasing the penetration depth, and enhancing both welding effect and efficiency.

[0004] Therefore, laser-arc hybrid welding has significant application value for welding medium-thickness steel plates with a thickness of 14mm-40mm. However, in existing technologies, for full-penetration butt joints and corner joints of medium-thickness steel plates with a thickness of 14mm-20mm, V-grooves or Y-grooves are required during welding. For full-penetration welding of steel plates thicker than 20mm, double-sided V-grooves, U-grooves, or K-grooves are required. Grooving is generally done mechanically, which is complex and leads to reduced welding efficiency and increased welding wire consumption. In addition, the larger the groove, the greater the cumulative welding heat input of the joint, the greater the shrinkage of the weld metal from the molten state to the solid state, the greater the thermal stress of the weld metal, and the greater the welding deformation.

[0005] Based on this, a laser-arc hybrid welding method suitable for medium-thickness steel plates and without beveling is provided. Summary of the Invention

[0006] This invention aims to address the technical problems in existing technologies for welding medium-thickness steel plates, which require beveling, leading to reduced welding efficiency, increased welding wire consumption, high thermal stress in the weld metal, and severe welding deformation. The goal is to provide a beveling-free laser-arc hybrid welding method for medium-thickness steel plates. By employing an I-bevel design and combining specific welding parameters, this method significantly improves the welding efficiency of butt joints and fillet joints in medium-thickness plates, reduces welding wire consumption, minimizes welding deformation, improves weld formation, and ensures that the mechanical properties of the weld metal meet relevant national standards.

[0007] The present invention is achieved through the following technical solution.

[0008] A method for laser-arc hybrid welding of medium-thickness steel plates without beveling includes the following steps:

[0009] (1) Pretreatment of welding metal;

[0010] (2) Welding metal assembly;

[0011] (3) Use type I groove, laser-guided or arc-guided welding, with the laser angle between the weld and the weld being 70°~90°, laser power 1kW-20kW, arc power 3kW-15kW, and welding speed 0.5m / min-3m / min.

[0012] This invention provides a laser-arc hybrid welding method that, by employing an I-groove and combining specific welding parameters, can significantly improve the welding efficiency of butt joints and fillet joints of medium and thick plates, reduce welding wire consumption, minimize welding deformation, and ensure that the mechanical properties of the weld metal meet relevant industry standards. Applicable welding metals include existing carbon structural steel, low-alloy high-strength steel, bridge steel, and weathering steel.

[0013] Furthermore, step (1) of the weld metal pretreatment includes:

[0014] Ensure the flatness of the opposite side of the weld metal assembly, and grind away rust and oil within 30mm of the weld.

[0015] Further, step (2) welding the metal assembly includes:

[0016] The pre-treated welded metal assemblies are spliced ​​together, and the gap between the assemblies is controlled to be less than or equal to the spot diameter when the laser defocus is zero, and the misalignment of the assemblies is less than 1mm.

[0017] Furthermore, it also includes preheating and dehumidifying after welding the metal assembly and before welding.

[0018] Furthermore, the preheating and dehumidification refers to:

[0019] When the ambient temperature is lower than 5°C or the air humidity is higher than 80%, the metal to be welded is preheated and dehumidified by means of flame, resistance heating or induction heating.

[0020] Further, when the thickness t of the steel plate is t≤30mm, the heating temperature is 30°C to 40°C, and when the thickness t of the steel plate is t>30mm, the heating temperature is 60°C to 200°C.

[0021] Preferably, welding is performed by adopting an arc leading mode.

[0022] The leading modes of laser-arc hybrid welding are divided into laser leading and arc leading. At present, the mainstream mode is laser leading. However, in the welding process of long straight welds, if the laser leading mode is adopted for welding, it is difficult to form the back of the middle and rear part of the weld. This is because the temperature of the steel plate rises during the welding process, the absorptivity to laser increases, the penetrability of laser to the steel plate is enhanced, and the penetration width at the back of the weld increases. Relying on the surface tension of the weld metal in a molten state, it is difficult to form the back of the weld, and a weld bead (also called a hump bead) will appear intermittently on the back weld pass. Therefore, the present invention preferably adopts the arc leading mode for welding.

[0023] In the present invention, the welding method for one-side welding with back formation for a 16mm thick steel plate adopts the arc leading mode. The arc has preheated the steel plate in advance, and the laser directly irradiates the weld metal in a molten state, which ensures that the laser absorptivity area is stable during the welding process of long straight welds, can effectively improve the formation of the back weld pass, and avoids the phenomenon of insufficient weld pass filling caused by the sagging of the back weld metal at the end of the weld during laser leading welding.

[0024] Further, for full penetration butt joint welding, when the thickness t of the steel plate is t≤20mm, one-side welding with back formation is adopted with a I-type groove, the included angle between the laser and the weld is 70°~90°, the laser power is 1kW-20kW, the arc power is 2kW-15kW, and the welding speed is 0.7m / min-3m / min.

[0025] Further, for full penetration butt joint welding, when the thickness of the steel plate is 20mm<t≤40mm, double-sided single-pass welding is adopted with a I-type groove, the included angle between the laser and the weld is 70° to 90°, the laser power is 7kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min.

[0026] Further, for full penetration fillet joint welding, when the thickness t of the steel plate is t≤40mm, double-sided single-pass welding is adopted with a I-type groove, the included angle between the laser and the weld is 70° to 90°, the included angle between the laser and the flange plate of the fillet joint is 0-15°, the laser power is 1kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0028] 1. This invention provides a laser-arc hybrid welding method. By adopting an I-groove design and combining specific welding parameters, it can significantly improve the welding efficiency of butt joints and fillet joints of medium and thick plates, reduce welding wire consumption, minimize welding deformation, and ensure that the mechanical properties of the weld metal meet relevant national standards. Applicable welding metals include existing carbon structural steel, low-alloy high-strength steel, bridge steel, and weathering steel.

[0029] 2. The present invention preferably uses an arc-guided welding method, in which the arc has preheated the steel plate in advance, and the laser is directly incident on the molten weld metal. In the welding process of long straight welds, the laser absorption rate region is kept stable, which can effectively improve the formation of the back weld bead. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0031] Figure 1 This is a diagram of the back side forming of a laser-guided single-sided weld (without backing).

[0032] Figure 2 This is a diagram showing the back-side forming of an arc-guided single-sided weld. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0034] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0035] The "scope" disclosed in this invention is defined in the form of a lower limit and an upper limit. A given scope is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific scope. The scope defined in this way can include or exclude end values, and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a scope.

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0037] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0038] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other substances not listed may also be included, or that only the listed substances may be included.

[0039] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0040] To address the technical problems of existing technologies that require beveling for welding medium-thickness steel plates, leading to reduced welding efficiency, increased welding wire consumption, high thermal stress in the weld metal, and severe welding deformation, this invention provides a beveling-free laser-arc hybrid welding method for medium-thickness steel plates, comprising the following steps:

[0041] (1) Pretreatment of welding metal: Ensure the flatness of the opposite side of the welding metal group, and grind away rust and oil stains within 30mm of the weld;

[0042] (2) Welding metal assembly: The pre-treated welding metal assemblies are spliced ​​together, and the gap between the assemblies is controlled to be less than or equal to the spot diameter when the laser defocus is 0, and the misalignment of the assemblies is less than 1 mm.

[0043] (3) Adopting a square groove form, welding is carried out in a laser-guided or arc-guided manner, the included angle between the laser and the weld seam is 70° to 90°, the included angle between the laser and the arc welding torch is ≥35°, the laser power is 1kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-3m / min. The specific welding is divided into multiple situations:

[0044] For full penetration butt joint welding, when the steel plate thickness t ≤ 20mm, the square groove form is adopted for one-side welding with back formation, the included angle between the laser and the weld seam is 70° to 90°, the included angle between the laser and the arc welding torch is ≥35°, the laser power is 1kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.9m / min-3m / min;

[0045] For full penetration butt joint welding, when the steel plate thickness satisfies 20mm < t ≤ 40mm, the square groove form is adopted for double-sided single-pass welding, the included angle between the laser and the weld seam is 70° to 90°, the included angle between the laser and the arc welding torch is ≤35°, the laser power is 7kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min;

[0046] For full penetration fillet joint welding, when the steel plate thickness t ≤ 40mm, the square groove form is adopted for double-sided single-pass welding, the included angle between the laser and the weld seam is 70° to 90°, the included angle between the laser and the arc welding torch is ≥35°, the included angle between the laser and the flange plate of the fillet joint is 75° to 90°, the laser power is 1kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min.

[0047] As a preferred option, the method further comprises preheating and dehumidifying after the welding metals are assembled and before welding.

[0048] Wherein, the preheating and dehumidifying refers to: when the ambient temperature is lower than 5°C or the air humidity is higher than 80°, the welding metal is preheated and dehumidified by means of flame heating, resistance heating or induction heating. When the steel plate thickness t ≤ 30mm, the heating temperature is 30°C to 40°C, and when the steel plate thickness t > 30mm, the heating temperature is 60°C to 200°C.

[0049] As a preferred option, welding is carried out in an arc-guided manner.

[0050] The technical solution of the present invention will be further described in detail below with reference to the examples.

[0051] It should be noted that the experimental methods used in the examples are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by those skilled in the art through commercial channels.

[0052] Example 1

[0053] This embodiment uses a steel plate with a thickness of t = 16 mm as an example of a fully penetrated butt joint, and provides a method for laser-arc hybrid welding of medium-thickness steel plates without beveling, including the following steps:

[0054] (1) Pretreatment of welding metal: Ensure the flatness of the opposite side of the welding metal group through material processing facilities, and grind the rust and oil stains within 30mm of the weld.

[0055] (2) Welded metal assembly: The pre-treated welded metal assemblies are put together, and the assembly gap is controlled to be less than or equal to the spot diameter when the laser defocus is 0, and the misalignment of the assembly is less than 1mm.

[0056] (3) Preheating and dehumidification: When the ambient temperature is below 5℃ or the air humidity is above 80%, flame heating is used to dehumidify the welded metal. The heating temperature is 35℃ for plate thickness t≤30mm and 100℃ for plate thickness t>30mm.

[0057] (4) Welding of penetration butt joint: The plate thickness t=16mm, the I-type groove is used for single-sided welding and back-side forming. Laser guidance (along the welding direction, the laser is in front and the arc is behind) requires a backing to be attached to the back of the weld to ensure the back-side forming of the weld. The angle between the laser and the weld is 87°, the angle between the laser and the arc welding gun is 30°, the laser power is 14.6kW, the arc power is 2.2kW, the defocusing amount is -5mm, and the welding speed is 0.84m / min.

[0058] Example 2

[0059] This embodiment takes the welding of a full penetration butt joint of a steel plate with a thickness of t=30mm as an example, and provides a laser-arc hybrid welding method for medium-thickness steel plates without beveling, including the following steps:

[0060] (1) Pretreatment of welding metal: Ensure the flatness of the opposite side of the welding metal group through material processing facilities, and grind the rust and oil stains within 30mm of the weld.

[0061] (2) Welded metal assembly: The pre-treated welded metal assemblies are put together, and the assembly gap is controlled to be less than or equal to the spot diameter when the laser defocus is 0, and the misalignment of the assembly is less than 1mm.

[0062] (3) Preheating and dehumidification: When the ambient temperature is below 5℃ or the air humidity is above 80%, flame heating is used to dehumidify the welded metal. The heating temperature is 35℃ for plate thickness t≤30mm and 150℃ for plate thickness t>30mm.

[0063] (4) Welding of full penetration butt joint: Plate thickness = t = 30mm, double-sided single-pass welding with type I groove, laser guidance (along the welding direction, laser in front, arc behind), no backing on the back of the weld, laser and weld angle 87°, laser and arc welding gun angle 30°, laser power 11.2kW, arc power 6.6kW, defocusing amount -5mm, welding speed 0.5m / min.

[0064] Example 3

[0065] This embodiment takes the welding of a full penetration fillet joint of a steel plate with a thickness of t=16mm as an example, and provides a laser-arc hybrid welding method for medium-thickness steel plates without beveling, including the following steps:

[0066] (1) Pretreatment of welding metal: Ensure the flatness of the opposite side of the welding metal group through material processing facilities, and grind the rust and oil stains within 30mm of the weld.

[0067] (2) Welded metal assembly: The pre-treated welded metal assemblies are put together, and the assembly gap is controlled to be less than or equal to the spot diameter when the laser defocus is 0, and the misalignment of the assembly is less than 1mm.

[0068] (3) Preheating and dehumidification: When the ambient temperature is below 5℃ or the air humidity is above 80%, flame heating is used to dehumidify the welded metal. The heating temperature is 35℃ for plate thickness t≤30mm and 80℃ for plate thickness t>30mm.

[0069] (4) Welding of fillet joints: The plate thickness is t=16mm. Double-sided single-pass welding is adopted in the form of I-type groove. Laser guidance (along the welding direction, the laser is in front and the arc is behind). No backing is applied on the back of the weld. The angle between the laser and the weld is 87°, the angle between the laser and the arc welding gun is 30°, the angle between the laser and the flange of the fillet joint is 10°, the laser power is 3kW, the arc power is 6.6kW, and the welding speed is 0.66m / min.

[0070] Comparative Example 1

[0071] This comparative example is compared with the embodiment, the difference being that it does not use laser guidance but uses arc guidance to verify the impact on the back weld bead. The specific steps include:

[0072] Includes the following steps:

[0073] (1) Pretreatment of welding metal: Ensure the flatness of the opposite side of the welding metal group through material processing facilities, and grind the rust and oil stains within 30mm of the weld.

[0074] (2) Welded metal assembly: The pre-treated welded metal assemblies are put together, and the assembly gap is controlled to be less than or equal to the spot diameter when the laser defocus is 0, and the misalignment of the assembly is less than 1mm.

[0075] (3) Preheating and dehumidification: When the ambient temperature is below 5℃ or the air humidity is above 80%, flame heating is used to dehumidify the welded metal. The heating temperature is 35℃ for plate thickness t≤30mm and 100℃ for plate thickness t>30mm.

[0076] (4) Welding of full penetration butt joint: plate thickness t = 16mm, single-sided welding with back forming in the form of I-type groove, arc guidance (along the welding direction, arc in front, laser behind), no backing on the back of the weld, laser and weld angle 87°, laser and arc welding gun angle 30°, laser power 14.6kW, arc power 2.2kW, defocusing amount -5mm, welding speed 0.84m / min.

[0077] The following are experimental verifications of the welding effects of the above embodiments and comparative examples:

[0078] 1. Compare the welds of Example 1 and Comparative Example 1 above, such as... Figure 1 and 2 As shown, where Figure 1 This diagram illustrates the back-side forming process for laser-guided welding, where a backing pad is attached. As can be seen from the image:

[0079] from Figure 1 It is evident that, under the same welding process parameters, after laser-guided welding begins, the start-up end of the weld on the back side has a stable weld height and no undercut. However, as welding continues, the base material temperature increases, leading to increased laser absorption and penetration depth. This causes the weld pool to collapse, and some weld metal detaches from the workpiece, resulting in a cut-like groove on the back side of the weld. Figure 2 It can be seen that the back side of the weld guided by the electric arc exhibits a stable reinforcement height. This is because the laser directly irradiates the weld pool during arc guidance, and the pre-arc completes the heating of the base material, making the absorption rate of the laser by the weld metal stable, thus making the back side of the weld form stable.

[0080] 2. The mechanical properties of the weld metal in the above embodiments and comparative examples were tested. The base material was hot-rolled Q355D steel plate. The results are shown in Table 1.

[0081] Table 1. Mechanical property data of weld metals in the examples and comparative examples.

[0082]

[0083] As can be seen from the data in Table 1:

[0084] The mechanical properties of the weld metal in the above embodiments all meet the requirements of the industry standard "Specifications for Manufacturing and Installation of Steel Structure Bridges for Highways" JTG / T 3651-2022. In Example 2 (plate thickness 30), the low-temperature impact absorption energy of the weld metal is less than 34J. According to the requirements of "Appendix C - Steel Welding Procedure Qualification" in JTG / T 3651-2022, the average value of the test results of each group (3 samples) of the impact test of the welded joint is not lower than the specified value, and any test result is not lower than 0.7 times the specified value, which is considered qualified. Therefore, the mechanical test results of Example 2 are qualified. It can be seen that the impact toughness of laser-coated composite welded joints is mostly slightly higher than the standard requirement value. Therefore, it is necessary to optimize the laser-coated composite welding process or perform post-weld heat treatment on the welded joint to improve the comprehensive mechanical properties of the welded joint.

[0085] Furthermore, the impact test results also showed that Comparative Example 1, which used an electric arc-guided method, had better mechanical properties than Example 1, which used a laser-guided method.

[0086] Finally, it should be noted that the above specific embodiments are only used to describe the purpose, technical solution, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation of the present invention and is not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing specific embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions or improvements to some or all of the technical features. Such modifications, equivalent substitutions, and improvements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for laser-arc hybrid welding of medium-thickness steel plates without beveling, characterized in that, comprising the following steps: (1) Pretreatment of welding metals; (2) Assembly of welding metals; (3) Welding is performed by adopting a I-type groove form and a laser guidance or arc guidance mode, wherein the included angle between the laser and the welding seam is 70°~90°, the laser power is 1kW-20kW, the arc power is 2kW-15kW, and the welding speed is 0.5m / min-3m / min.

2. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, Step (1) the pretreatment of welding metals comprises: ensuring the flatness of the assembly surfaces of the welding metals, and grinding off rust and oil stains within 30mm near the welding seam.

3. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 2, characterized in that, Step (2) the assembly of welding metals comprises: splicing the pretreated welding metals together in an assembly manner, controlling the assembly gap to be less than or equal to the spot diameter at the zero defocusing amount of the laser, and controlling the assembly misalignment to be less than 1mm.

4. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, The method further comprises preheating for dehumidification after the assembly of the welding metals and before welding.

5. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 4, characterized in that, The preheating for dehumidification refers to: when the ambient temperature is lower than 5℃ or the air humidity is higher than 80%, preheating and dehumidifying the welding metals by means of flame heating, resistance heating or induction heating.

6. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 5, characterized in that, When the thickness t of the steel plate is t≤30mm, the heating temperature is 30℃ to 40℃, and when the thickness t of the steel plate is t>30mm, the heating temperature is 60℃ to 200℃.

7. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, Welding is performed by adopting an arc guidance mode.

8. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, For full penetration butt joint welding, when the thickness t of the steel plate is t≤20mm, single-side welding with back formation is adopted in the form of a I-type groove, the included angle between the laser and the welding seam is 70°~90°, the laser power is 1kW-20kW, the arc power is 2kW-15kW, and the welding speed is 0.7m / min-3m / min.

9. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, For full penetration butt joint welding, when the thickness of the steel plate is 20mm<t≤40mm, double-sided single-pass welding is adopted in the form of a I-type groove, the included angle between the laser and the welding seam is 70°~90°, the laser power is 7kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min.

10. The method for laser-arc hybrid welding of medium-thickness steel plates without beveling according to claim 1, characterized in that, For full penetration fillet joint welding, when the thickness t of the steel plate is t≤40mm, double-sided single-pass welding is adopted in the form of a I-type groove, the included angle between the laser and the welding seam is 70°~90°, the included angle between the laser and the flange plate of the fillet joint is 0-15°, the laser power is 1kW-20kW, the arc power is 3kW-15kW, and the welding speed is 0.5m / min-1m / min.

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