Laser arc composite full penetration welding method capable of overcoming splashing defect

Abstract

The invention provides a laser-arc composite full penetration welding method capable of overcoming the splashing defect, which comprises the following steps: S1, processing a groove in the to-be-welded surface of a to-be-welded workpiece, polishing and cleaning the to-be-welded surface and the groove after processing, and then attaching and fixing the to-be-welded surfaces of the two to-be-welded workpieces; and S2, the laser machining head and the MIG welding gun are fixed, the included angle between the angle of the laser machining head and the central axis of the MIG welding gun ranges from 15 degrees to 30 degrees, then a welding machine and a laser device are started, and laser-electric arc hybrid welding is completed under protection of the electric arc and laser hybrid heat source and the protective gas. According to the method, after the MIG welding gun is adjusted to be in the pulse mode and the arc length correction coefficient is adjusted to be-18%--24%, the splashing problem existing in laser-electric arc composite connection can be perfectly solved, additional cost input is not needed in the whole process, and the method is suitable for large-scale industrial production and has very high popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of metal material welding, and in particular to a laser arc composite full penetration welding method capable of overcoming spatter defects. Background Art

[0002] Laser-arc hybrid welding technology is an advanced connection technology that cleverly combines the advantages of laser welding and arc welding, namely the high precision and speed of laser welding and the strong adaptability of arc welding to materials. This technology uses both laser beam and arc as heat sources, which not only increases the welding speed, but also enhances the stability of the welding process, achieves a deeper penetration, reduces the heat input during welding, reduces welding residual stress and deformation, and thus improves the quality and performance of the welded joint.

[0003] However, in practical applications, laser-arc hybrid welding technology faces some challenges. First, due to the possibility of burrs, plate bending or assembly misalignment in the workpiece, these problems will lead to instability in the welding process, especially when dealing with workpieces with complex geometries. These instabilities can easily cause welding spatter, affecting the surface quality and internal structure of the welded joint, and thus affecting the overall performance of the welded structure. In addition, welding spatter will also increase the cost of subsequent processing, such as grinding and repair work, which not only increases production costs but also prolongs the production cycle.

[0004] To overcome these challenges, researchers have explored a variety of solutions. On the one hand, by optimizing the ratio of shielding gas, such as adding an appropriate amount of CO2 gas, the stability of the welding process can be effectively improved and the occurrence of spatter can be reduced. On the other hand, adding activators to the welding area has also been proven to be an effective strategy. For example, activators such as TiO2 and ZnO decompose at high temperatures, and the released oxygen can further shrink the arc, reduce metal overheating and spatter, and improve the wettability and filling of the molten pool.

[0005] Although the above methods can alleviate the problems in the welding process to a certain extent, for industrial environments that require large-scale production, the adjustment of the shielding gas ratio and the addition of activators greatly increase the labor cost, time cost and production cost. Therefore, the development of more economical and efficient solutions has become the focus of current research. Summary of the invention

[0006] In view of the current lack of a method that can cost-effectively and efficiently solve the spatter problem in laser-arc hybrid welding, the present invention provides a laser arc hybrid full penetration welding method that can overcome the spatter defect. It can not only effectively solve the spatter problem in laser-arc hybrid welding and significantly improve the weld formation quality, but also does not require additional cost investment and is suitable for large-scale industrial production.

[0007] The present invention achieves the above technical objectives through the following technical means.

[0008] A laser arc hybrid full penetration welding method capable of overcoming spatter defects comprises the following steps:

[0009] S1: Processing a groove on the surface to be welded of the workpiece to be welded, grinding and cleaning the surface to be welded and the groove after processing, and then attaching and fixing the surfaces to be welded of the two workpieces to be welded;

[0010] S2: Fix the laser processing head and the MIG welding gun, and make the angle of the laser processing head and the central axis of the MIG welding gun form an angle of 15° to 30°. Then turn on the welding machine and the laser, and complete the laser arc hybrid welding under the protection of the arc and laser composite heat source and the shielding gas.

[0011] The working parameters of the laser processing head are as follows: laser power is 3.5-5.2kw, defocus is -2 to +5mm, and filament spacing is 2 to 3mm;

[0012] The working parameters of the MIG welding gun are as follows: the current mode adopts the pulse mode, and the arc length correction coefficient is -18% to -24%; the specific parameters of the pulse mode are as follows: the base current is 60 to 80A, the pulse peak current is 230 to 280A, the pulse frequency is 120 to 130Hz, the pulse period is 6 to 9ms, of which the peak time is 4 to 6ms, and the base time is 2 to 4ms.

[0013] Furthermore, the material of the workpiece to be welded in step S1 is high-strength steel, stainless steel or carbon steel.

[0014] Furthermore, the thickness of the workpiece to be welded in step S1 is 4-7 mm.

[0015] Furthermore, the groove described in step S1 is an I-type groove; and the joint form is a flat butt joint.

[0016] Furthermore, the cleaning method described in step S1 is: wiping acetone on the surface to be welded and the groove of the workpiece to be welded.

[0017] Furthermore, in step S2, before performing laser arc hybrid welding, the MIG welding gun shielding gas nozzle is pre-flown with shielding gas for 3 to 5 seconds; after the laser arc hybrid welding is completed, the MIG welding gun shielding gas nozzle continues to deliver shielding gas for 3 to 5 seconds.

[0018] Furthermore, the welding speed of the laser arc hybrid welding in step S2 is 1.08m / min~1.2m / min, and the working parameters of the MIG welding gun are: the current mode adopts the pulse mode, and the arc length correction coefficient is -20%; the specific parameters of the pulse mode are: the base current is 60~80A, the pulse peak current is 230~280A, the pulse frequency is 125Hz, and the pulse period is 8ms, of which the peak time is 5ms and the base time is 3ms.

[0019] Furthermore, in step S2, a JM-56 solid welding wire with a diameter of 1 to 1.6 mm is used during laser arc hybrid welding.

[0020] Furthermore, the laser in step S2 is a fiber laser, a solid laser or a gas laser, and the laser is a continuous laser.

[0021] Furthermore, the protective gas in step S2 is 80% Ar+20% CO2, and the protective gas flow rate is 20 L / min.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The MIG welding gun in the present invention adopts a pulse mode, and only one drop of metal is ejected from the tip of the welding wire in each pulse cycle, forming a "one pulse one drop" transition mode. This "one pulse one drop" transition mode is based on precise pulse parameter adjustment, including peak current, base current, pulse frequency, peak time and base time. This mode can avoid spattering caused by high current injection, ensure that the molten droplet enters the molten pool smoothly, avoid molten pool fluctuations and irregular flow, and further improve the forming quality of the weld.

[0024] 2. Based on the "one pulse one drop" transition mode, the present invention can safely use higher current and voltage without worrying about excessive spatter. It can not only accelerate the melting rate of the welding wire, increase the welding speed, shorten the production cycle, and improve production efficiency, but also provide more energy to make the heat input of the laser and arc more concentrated, thereby achieving a deeper melting depth and a wider melting width, which is particularly suitable for the welding of medium and thick plates.

[0025] 3. The arc length correction coefficient of the MIG welding gun in the present invention is -20%, which ensures good arc straightness and energy concentration, reduces the deviation and swing of the arc during welding, and ensures that the arc can be accurately focused on the weld. At the same time, the interference between the laser and the arc is small, avoiding the fluctuation and instability caused by the interaction between the laser and the arc, and further improving the forming quality of the weld.

[0026] 4. The laser arc composite full penetration welding method of the present invention can perfectly solve the spatter problem existing in the laser-arc composite welding after the MIG welding gun is adjusted to the pulse mode and the arc length correction coefficient is adjusted to -20%. The whole process does not require additional cost investment, is suitable for large-scale industrial production, and has a high promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of an arc with an arc length correction factor of -20%.

[0028] Figure 2 Schematic diagram of an arc with an arc length correction coefficient of 0.

[0029] Figure 3 This is a pulse waveform diagram of the MIG welding gun of the present invention in pulse mode.

[0030] Figure 4 This is a surface morphology of the weld obtained by the welding method described in Example 1.

[0031] Figure 5 This is a surface morphology of the weld obtained by the welding method described in Example 2.

[0032] Figure 6 This is a surface morphology of the weld obtained by the welding method described in Example 3. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] Example 1

[0035] The laser arc hybrid full penetration welding method capable of overcoming spatter defects described in this embodiment comprises the following steps:

[0036] S1: A 6mm thick EH36 high-strength steel medium and thick plate is used as the workpiece to be welded. A type I groove is processed on the surface to be welded of the workpiece to be welded by laser cutting. The joint form is a flat butt joint. After processing, the surface to be welded and the groove are polished and wiped with acetone, and then the surfaces to be welded of the two workpieces to be welded are attached and fixed.

[0037] S2: Fix the laser processing head and the MIG welding gun, and the angle of the laser processing head and the central axis of the MIG welding gun are at an angle of 15°. Before laser arc hybrid welding, the MIG welding gun shielding gas nozzle is pre-flown with shielding gas for 5 seconds. Then, the arc is used as a heat source, and under the protection of shielding gas, the laser arc hybrid welding is completed at a welding speed of 1.08m / min, a welding current of 260A, and a welding voltage of 26V. After the laser arc hybrid welding is completed, the MIG welding gun shielding gas nozzle continues to deliver shielding gas for 5 seconds.

[0038] The laser processing head used in this embodiment is a Raycus RFL-C12000 laser, and the working parameters of the laser processing head are: laser power of 4.8kw, defocus of -2mm, and filament spacing of 3mm.

[0039] In this embodiment, a German LORCH MIG arc welding machine is used, and the working parameters of the MIG welding gun are: the current mode adopts the DC mode, the arc length correction coefficient is -20%, Figure 1 Schematic diagram of an arc with an arc length correction factor of -20%.

[0040] The protective gas used in this embodiment is 80% Ar+20% CO2, and the protective gas flow rate is 20 L / min.

[0041] In this embodiment, a JM-56 solid welding wire with a diameter of 1.2 mm is used during laser arc hybrid welding.

[0042] Example 2

[0043] The laser arc hybrid full penetration welding method capable of overcoming spatter defects described in this embodiment comprises the following steps:

[0044] S1: A 6mm thick EH36 high-strength steel medium and thick plate is used as the workpiece to be welded. A type I groove is processed on the surface to be welded of the workpiece to be welded by laser cutting. The joint form is a flat butt joint. After processing, the surface to be welded and the groove are polished and wiped with acetone, and then the surfaces to be welded of the two workpieces to be welded are attached and fixed.

[0045] S2: Fix the laser processing head and the MIG welding gun, and the angle of the laser processing head and the central axis of the MIG welding gun are at an angle of 15°. Before laser arc hybrid welding, the MIG welding gun shielding gas nozzle is pre-flown with shielding gas for 5 seconds. Then, the arc is used as a heat source, and under the protection of shielding gas, the laser arc hybrid welding is completed at a welding speed of 1.08m / min, a welding current of 260A, and a welding voltage of 26V. After the laser arc hybrid welding is completed, the MIG welding gun shielding gas nozzle continues to deliver shielding gas for 5 seconds.

[0046] The laser processing head used in this embodiment is a Raycus RFL-C12000 laser, and the working parameters of the laser processing head are: laser power of 4.8kw, defocus of -2mm, and filament spacing of 3mm.

[0047] In this embodiment, a German LORCH MIG arc welding machine is used, and the working parameters of the MIG welding gun are: the current mode adopts the pulse mode, the arc length correction coefficient is 0, Figure 2 Schematic diagram of an arc with an arc length correction coefficient of 0. Specific parameters of the pulse mode: base current is 80A, pulse peak current is 260A, pulse frequency is 125Hz, pulse period is 8ms, of which peak time is 5ms, base time is 3ms, Figure 3 This is the pulse waveform of the MIG welding gun in pulse mode.

[0048] The protective gas used in this embodiment is 80% Ar+20% CO2, and the protective gas flow rate is 20 L / min.

[0049] In this embodiment, a JM-56 solid welding wire with a diameter of 1.2 mm is used during laser arc hybrid welding.

[0050] Example 3

[0051] The laser arc hybrid full penetration welding method capable of overcoming spatter defects described in this embodiment comprises the following steps:

[0052] S1: A 6mm thick EH36 high-strength steel medium and thick plate is used as the workpiece to be welded. A type I groove is processed on the surface to be welded of the workpiece to be welded by laser cutting. The joint form is a flat butt joint. After processing, the surface to be welded and the groove are polished and wiped with acetone, and then the surfaces to be welded of the two workpieces to be welded are attached and fixed.

[0053] S2: Fix the laser processing head and the MIG welding gun, and the angle of the laser processing head and the central axis of the MIG welding gun are at an angle of 15°. Before laser arc hybrid welding, the MIG welding gun shielding gas nozzle is pre-flown with shielding gas for 5 seconds. Then, the arc is used as a heat source, and under the protection of shielding gas, the laser arc hybrid welding is completed at a welding speed of 1.08m / min, a welding current of 260A, and a welding voltage of 26V. After the laser arc hybrid welding is completed, the MIG welding gun shielding gas nozzle continues to deliver shielding gas for 5 seconds.

[0054] The laser processing head used in this embodiment is a Raycus RFL-C12000 laser, and the working parameters of the laser processing head are: laser power of 4.8kw, defocus of -2mm, and filament spacing of 3mm.

[0055] In this embodiment, a German LORCH MIG arc welding machine is used, and the working parameters of the MIG welding gun are: the current mode adopts the pulse mode, and the arc length correction coefficient is -20%. The specific parameters of the pulse mode are: the base current is 80A, the pulse peak current is 260A, the pulse frequency is 125Hz, the pulse period is 8ms, wherein the peak time is 5ms, and the base time is 3ms.

[0056] The protective gas used in this embodiment is 80% Ar+20% CO2, and the protective gas flow rate is 20 L / min.

[0057] In this embodiment, a JM-56 solid welding wire with a diameter of 1.2 mm is used during laser arc hybrid welding.

[0058] The welds after welding in Examples 1 to 3 were photographed. Figure 4 , 5 6 are the weld morphology diagrams in Examples 1, 2, and 3, respectively. It can be seen from the figure that in DC mode, when the arc length correction coefficient is -20%, there is a lot of spatter on the weld surface. In pulse mode, when the arc length correction coefficient is 0, there is still a lot of spatter around the weld. In pulse mode, when the arc length correction coefficient is -20%, the weld surface presents high continuity and uniformity, and no spatter defects are generated.

[0059] The results of the examples show that the laser-arc hybrid welding process and parameters proposed by the present invention based on the negative arc length correction coefficient and the arc welding machine in pulse mode can solve the spatter problem of laser-arc hybrid welding. The present invention provides an important technical reference for promoting the development of laser-arc hybrid welding technology and promoting the widespread application of laser-arc hybrid welding in the field of medium and thick plate butt welding, and has potential economic and social benefits.

[0060] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A laser arc hybrid full penetration welding method capable of overcoming spatter defects, characterized in that: The following steps are involved: S1: Processing a groove on the surface to be welded of the workpiece to be welded, grinding and cleaning the surface to be welded and the groove after processing, and then attaching and fixing the surfaces to be welded of the two workpieces to be welded; S2: Fix the laser processing head and the MIG welding gun, and make the angle of the laser processing head and the central axis of the MIG welding gun form an angle of 15° to 30°. Then turn on the welding machine and the laser, and complete the laser arc hybrid welding under the protection of the arc and laser composite heat source and the shielding gas. The working parameters of the laser processing head are as follows: laser power is 3.5-5.2kw, defocus is -2 to +5mm, and filament spacing is 2 to 3mm; The working parameters of the MIG welding gun are as follows: the current mode adopts the pulse mode, and the arc length correction coefficient is -18% to -24%; the specific parameters of the pulse mode are as follows: the base current is 60 to 80A, the pulse peak current is 230 to 280A, the pulse frequency is 120 to 130Hz, the pulse period is 6 to 9ms, of which the peak time is 4 to 6ms, and the base time is 2 to 4ms.

2. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The material of the workpiece to be welded in step S1 is high-strength steel, stainless steel or carbon steel.

3. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The thickness of the workpiece to be welded in step S1 is 4-7 mm.

4. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The groove described in step S1 is an I-type groove; the joint form is a flat butt joint.

5. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The cleaning method described in step S1 is: wiping acetone on the surface to be welded and the groove of the workpiece to be welded.

6. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: In step S2, before performing laser arc hybrid welding, the MIG welding gun shielding gas nozzle is pre-flown with shielding gas for 3 to 5 seconds; after the laser arc hybrid welding is completed, the MIG welding gun shielding gas nozzle continues to deliver shielding gas for 3 to 5 seconds.

7. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The welding speed of the laser arc hybrid welding in step S2 is 1.08m / min~1.2m / min; the working parameters of the MIG welding gun: the current mode adopts the pulse mode, and the arc length correction coefficient is -20%; the specific parameters of the pulse mode are: the base current is 60~80A, the pulse peak current is 230~280A, the pulse frequency is 125Hz, the pulse period is 8ms, of which the peak time is 5ms and the base time is 3ms.

8. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: In step S2, a JM-56 solid welding wire with a diameter of 1 to 1.6 mm is used during laser arc hybrid welding.

9. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The laser described in step S2 is a fiber laser, a solid laser or a gas laser, and the laser is a continuous laser.

10. The laser arc hybrid full penetration welding method according to claim 1, characterized in that: The protective gas described in step S2 is 80% Ar+20% CO2, and the protective gas flow rate is 20 L / min.

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