CMT bottoming laser arc hybrid welding process for butt joint

Abstract

The CMT bottoming laser-arc hybrid welding process comprises the steps that the joint of a to-be-welded base material is polished to remove oxide skin, the to-be-welded base material is cleaned up, and the to-be-welded base material is fixed to a workbench through a clamp; a CMT welding gun is fixed to the robot, the angle between a welding wire used by the CMT welding gun and the upper surface of the to-be-welded base metal ranges from 25 degrees to 70 degrees, and CMT backing welding is conducted; the MIG welding gun is fixed to the robot, the wire feeding end of the MIG welding gun is arranged at the position 1-3 mm away from a laser beam emitted by the laser device in front, the laser beam is perpendicular to the welding direction, the angle between a welding wire used by the MIG welding gun and the upper surface of the to-be-welded base metal ranges from 25 degrees to 70 degrees, and laser welding and MIG electric arc welding composite welding is conducted. The composite welding process has the advantages of being large in welding penetration depth, high in welding speed, small in workpiece deformation, low in assembly requirement, high in molten pool bridging capacity, high in welding quality, good in welding seam performance, easy to achieve automatic welding and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a CMT base laser arc hybrid welding process for butt jointing. Background Art

[0002] Laser arc hybrid welding technology is a new welding technology developed in recent years. It is mainly used for the connection of thick plates over 10mm. The welding of cantilevers in engineering machinery production has been widely used in this technology, which can effectively solve the problems of many defects and large deformation of traditional fusion welding. Laser welding has many advantages such as concentrated energy and easy control, narrow heat-affected zone, large penetration, fast welding speed, small residual stress after welding, and small deformation.

[0003] Laser arc hybrid welding combines the complementary advantages of laser welding's deep penetration and MIG arc's wide penetration, and has been used to a certain extent in industrial production. Generally speaking, laser in front and arc in the back can achieve better process performance, but for thick plate welding, the back collapse and weld nodules are prone to occur when this process is used for base welding. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a CMT base laser arc hybrid welding process for butt jointing, which effectively solves the problems of collapse and weld nodules on the back of the weld.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a CMT bottom laser arc hybrid welding process for butt joint, comprising the following steps:

[0007] S1: Use 150-grit sandpaper to grind the joint of the base material to be welded to remove the oxide scale, and then clean it;

[0008] S2: The base material to be welded after being processed in step S1 is fixed on the composite welding workbench by using a fixture;

[0009] S3: Fixing the CMT welding gun on the robot, the angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 25-70°;

[0010] S4, CMT base welding;

[0011] S5. Fix the MIG welding gun on the robot, the wire feeding end of the MIG welding gun is placed 1-3 mm in front of the laser beam emitted by the laser, the laser beam is perpendicular to the welding direction, and the angle between the welding wire of the MIG welding gun and the upper surface of the base material to be welded is 25-70°;

[0012] S6, laser welding and MIG arc welding hybrid welding.

[0013] Preferably, the thickness of the base material to be welded is 15-22 mm, and the welding wire used for the CMT welding gun and the MIG welding gun is selected according to the material of the base material to be welded; the welding wire is an ordinary welding wire or a high-strength steel welding wire with copper coating on the surface. When using ordinary welding wire, the welding wire is subjected to pre-welding treatment of degreasing, pickling and drying.

[0014] Preferably, in step S1, the joint of the base material to be welded is cleaned by alcohol or acetone.

[0015] Preferably, in step S3, the diameter of the welding wire of the CMT welding gun is 1.2 mm, the current of the welding wire is 100-150 A, the arc voltage is 16-20 V, and the wire feeding speed is 4-8 m / min.

[0016] Preferably, in step S3, the coaxial shielding gas of the CMT welding gun is argon gas with a purity of 99.99%, and the shielding gas flow rate is 15-25 L / min.

[0017] Preferably, in step S5, the diameter of the MIG welding gun is 1.2 mm, the current of the welding wire is 150-220 A, the arc voltage is 20-30 V, and the wire feeding speed is 4-8 m / min.

[0018] Preferably, in step S5, the distance between the welding wire used by the MIG welding gun and the upper surface of the base material to be welded is 1-2 mm.

[0019] Preferably, in step S5, the coaxial shielding gas of the MIG welding gun is argon gas with a purity of 99.99%, and the shielding gas flow rate is 15-25 L / min.

[0020] Preferably, in step S6, the power of the laser is 5-10 kW, the laser spot diameter is 0.4-0.6 mm, the laser defocus is 0 mm, and the welding speed is 0.5-1.0 m / min.

[0021] Preferably, in step S6, the two heat sources of laser welding and MIG arc welding form one heat source and a common molten pool, and the welding wire is fed into the molten pool surface through a MIG welding gun to form a short-circuit transition, and in the case of high current, it is a jet transition without arc interruption.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The CMT base laser arc hybrid welding process can prevent the defect of excessive weld nodules on the back of the weld. It has the advantages of large welding penetration, fast welding speed, small workpiece deformation, low assembly requirements, high welding quality, good weld performance and easy automatic welding. It is suitable for welding occasions such as aircraft decks, ship decks, automobile panels, and engineering mechanical arms. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a welding state diagram of the CMT base laser arc hybrid welding process for butt jointing in the embodiment; wherein: 1 laser beam; 2 weld; 3 MIG welding gun; 4 base material to be welded; 5 welding wire. DETAILED DESCRIPTION

[0025] In order to make the technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Figure 1 An exemplary CMT backing laser arc hybrid welding process for butt joint is described, comprising the following steps:

[0027] S1. Grind the joint of the base material 4 to be welded with 150-grit sandpaper to remove the oxide scale, then clean it, and clean the joint of the base material 4 to be welded with alcohol or acetone;

[0028] S2, using a clamp to fix the base material 4 to be welded on the composite welding workbench;

[0029] S3. Fix the CMT welding gun on the robot, and the angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 25-70°;

[0030] S4, perform CMT base welding;

[0031] S5, fix the MIG welding gun 3 on the robot, and place the wire feeding end of the MIG welding gun 3 1-3 mm in front of the laser beam emitted by the laser, the laser beam 1 is perpendicular to the welding direction, and the angle between the welding wire 5 of the MIG welding gun 3 and the upper surface of the base material 4 to be welded is 25-70°;

[0032] S6. Laser arc hybrid welding.

[0033] In some embodiments, the thickness of the base material 4 to be welded is 15-22 mm. The welding wire used in the welding gun is selected according to the material of the base material to be welded. The welding wire is an ordinary welding wire or a high-strength steel welding wire with copper coating on the surface. When using ordinary welding wire, the welding wire needs to be degreased, pickled and dried before welding to ensure that there are no impurities.

[0034] In some embodiments, in step S3, the diameter of the welding wire of the CMT welding gun is 1.2 mm, the current of the welding wire is 100-150 A, the arc voltage is 16-20 V, and the wire feeding speed is 4-8 m / min.

[0035] In some embodiments, in step S5, the diameter of the welding wire of the MIG welding gun is 1.2 mm, the current of the welding wire is 150-220 A, the arc voltage is 20-30 V, and the wire feeding speed is 4-8 m / min.

[0036] In some embodiments, in step S5, the distance between the welding wire 5 of the MIG welding gun and the upper surface of the base material 4 to be welded is 1-2 mm.

[0037] In some embodiments, in steps S3 and S5, the coaxial shielding gas of the CMT welding gun and the MIG welding gun are both argon gas with a purity of 99.99%, and the coaxial shielding gas flow rate of the welding gun is 15-25 L / min.

[0038] In some embodiments, in step S5, when the laser and the welding wire are at different spacings, the coupling and effect of the laser and the MIG arc are different, which significantly affects the shape and size of the arc and the longitudinal length and transverse width of the welding pool. At the same time, a larger inclination angle (40-70°) can be used when the butt welding gap is small, but a smaller inclination angle (25-40°) must be used when the butt welding gap is large. The inclination angle of the welding wire of the MIG welding gun affects the spatial distribution of the arc energy.

[0039] In some embodiments, in step S6, the laser output power is 5-10 kW, the laser spot diameter is 0.4-0.6 mm, the laser defocus is 0 mm, and the welding speed is 0.5-1 m / min.

[0040] In some embodiments, in step S6, the two heat sources of laser welding and MIG arc welding form one heat source and a common molten pool, and the welding wire is fed into the surface of the molten pool through the MIG welding gun to form a short-circuit transition, and in the case of high current, it is a jet transition without arc interruption.

[0041] Example 1

[0042] This embodiment proposes a CMT bottom laser arc hybrid welding process for butt jointing, and the steps are as follows:

[0043] S1. Take a 15mm thick base metal to be welded, grind the joint of the base metal with 150-grit sandpaper to remove the oxide scale, and then clean the joint of the base metal with alcohol or acetone.

[0044] S2. Use a clamp to fix the base material to be welded on the composite welding workbench.

[0045] S3. Fix the CMT welding gun on the robot. The angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 25°. The distance between the welding wire and the upper surface of the base material to be welded is 2mm. The welding wire used for the welding gun is selected according to the material of the base material to be welded. The welding wire is ordinary welding wire or high-strength steel welding wire with copper coating on the surface. When using ordinary welding wire, the welding wire shall be degreased, pickled and dried before welding to ensure that there are no impurities.

[0046] S4, CMT base welding, the wire diameter of the CMT welding gun is 1.2mm, the welding wire current is 100A, the arc voltage is 16V, and the wire feeding speed is 4m / min.

[0047] S5. Fix the MIG welding gun on the robot so that the wire feeding end of the MIG welding gun is placed 3mm in front of the laser beam emitted by the laser, the laser beam is perpendicular to the welding direction, the angle between the welding wire of the MIG welding gun and the upper surface of the base material to be welded is 25°, and the working parameters are set as follows: the diameter of the welding wire of the MIG welding gun is 1.2mm, the current of the welding wire is 150A, the arc voltage is 20V, and the wire feeding speed is 4m / min; the coaxial shielding gas of the CMT welding gun and the MIG welding gun are both argon with a purity of 99.99% and a flow rate of 15L / min; the laser output power is 5kW, the laser spot diameter is 0.4mm, the laser defocus is 0mm, and the welding speed is 0.5m / min.

[0048] S6, laser arc hybrid welding, laser welding and MIG arc welding two heat sources form a heat source and form a common molten pool, the welding wire is fed into the molten pool surface through the MIG welding gun to form a short-circuit transition, and in the case of high current, it is a jet transition and the arc is no longer broken.

[0049] Example 2

[0050] This embodiment proposes a CMT bottom laser arc hybrid welding process for butt jointing, and the steps are as follows:

[0051] S1. Take a 18mm thick base metal to be welded, grind the joint of the base metal with 150-grit sandpaper to remove the oxide scale, and then clean the joint of the base metal with alcohol or acetone.

[0052] S2. Use a clamp to fix the base material to be welded on the composite welding workbench.

[0053] S3. Fix the CMT welding gun on the robot. The angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 40°. The distance between the welding wire and the upper surface of the base material to be welded is 1.5mm. The welding wire used for the welding gun is selected according to the material of the base material to be welded. The welding wire is ordinary welding wire or copper-plated high-strength steel welding wire. When using ordinary welding wire, the welding wire is degreased, pickled and dried before welding to ensure that there are no impurities.

[0054] S4, CMT base welding, the wire diameter of the CMT welding gun is 1.2mm, the welding wire current is 120A, the arc voltage is 18V, and the wire feeding speed is 6m / min.

[0055] S5. Fix the MIG welding gun on the robot so that the wire feeding end of the MIG welding gun is placed 2mm in front of the laser beam emitted by the laser, the laser beam is perpendicular to the welding direction, and the angle between the welding wire of the MIG welding gun and the upper surface of the base material to be welded is 40°; set the working parameters as follows: the diameter of the welding wire of the MIG welding gun is 1.2mm, the current of the welding wire is 180A, the arc voltage is 20V, and the wire feeding speed is 6m / min; the coaxial shielding gas of the CMT welding gun and the MIG welding gun are both argon with a purity of 99.99% and a flow rate of 20L / min; the laser output power is 8kW, the laser spot diameter is 0.5mm, the laser defocus is 0mm, and the welding speed is 0.8m / min.

[0056] S6, laser arc hybrid welding, laser welding and MIG arc welding two heat sources form a heat source and form a common molten pool, the welding wire is fed into the molten pool surface through the MIG welding gun to form a short-circuit transition, and in the case of high current, it is a jet transition and the arc is no longer broken.

[0057] Example 3

[0058] This embodiment proposes a CMT bottom laser arc hybrid welding process for butt jointing, and the steps are as follows:

[0059] S1. Take a 22mm thick base metal to be welded, grind the joint of the base metal with 150-grit sandpaper to remove the oxide scale, and then clean the joint of the base metal with alcohol or acetone.

[0060] S2. Use a clamp to fix the base material to be welded on the composite welding workbench.

[0061] S3. Fix the CMT welding gun on the robot. The angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 70°. The distance between the welding wire and the upper surface of the base material to be welded is 1mm. The welding wire used for the welding gun is selected according to the material of the base material to be welded. The welding wire is ordinary welding wire or high-strength steel welding wire with copper coating on the surface. When ordinary welding wire is used, the welding wire is degreased, pickled and dried before welding to ensure that there are no impurities.

[0062] S4, CMT base welding, the wire diameter of the CMT welding gun is 1.2mm, the current of the welding wire is 150A, the arc voltage is 20V, and the wire feeding speed is 8m / min.

[0063] S5. Fix the MIG welding gun on the robot so that the wire feeding end of the MIG welding gun is placed 1mm in front of the laser beam emitted by the laser, the laser beam is perpendicular to the welding direction, and the angle between the welding wire of the MIG welding gun and the upper surface of the base material to be welded is 70°; set the working parameters as follows: the diameter of the welding wire of the MIG welding gun is 1.2mm, the current of the welding wire is 220A, the arc voltage is 30V, and the wire feeding speed is 8m / min; the coaxial shielding gas of the CMT welding gun and the MIG welding gun are both argon with a purity of 99.99% and a flow rate of 25L / min; the laser output power is 10kW, the laser spot diameter is 0.6mm, the laser defocus is 0mm, and the welding speed is 1m / min.

[0064] S6, laser arc hybrid welding, laser welding and MIG arc welding two heat sources form a heat source and form a common molten pool, the welding wire is fed into the molten pool surface through the MIG welding gun to form a short-circuit transition, and in the case of high current, it is a jet transition and the arc is no longer broken.

[0065] In summary, the CMT-based laser arc hybrid welding process for butt jointing in the present invention has the following advantages: good weld formation, good gas protection, uniform weld grain size, no cracks, incomplete penetration and incomplete fusion inside the weld seal, and no visible inclusions and pores. In particular, the CMT-based laser arc hybrid welding process of the present invention expands the application scope of laser high-strength steel structures under large gaps, improves welding quality and welding efficiency, reduces welding costs, has no special requirements for the environment, has strong adaptability to welding gap size, does not require special pre-welding preheating and post-welding treatment, is easy to implement in the welding process, has high work efficiency, and is suitable for welding aircraft decks, ship decks, automobile panels, engineering machinery arms and other occasions.

[0066] The above is a preferred embodiment of the present invention, but the present invention should not be limited to the contents disclosed in the embodiment. Therefore, any equivalent or modification completed without departing from the spirit disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A CMT primer laser arc hybrid welding process for butt jointing, characterized in that: The following steps are involved: S1: Use 150-grit sandpaper to grind the joint of the base material to be welded to remove the oxide scale, and then clean it; S2: The base material to be welded after being processed in step S1 is fixed on the composite welding workbench by using a fixture; S3: Fixing the CMT welding gun on the robot, the angle between the welding wire of the CMT welding gun and the upper surface of the base material to be welded is 25-70°; S4, CMT base welding; S5. Fix the MIG welding gun on the robot, the wire feeding end of the MIG welding gun is placed 1-3 mm in front of the laser beam emitted by the laser, the laser beam is perpendicular to the welding direction, and the angle between the welding wire of the MIG welding gun and the upper surface of the base material to be welded is 25-70°; S6, laser welding and MIG arc welding hybrid welding.

2. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: The thickness of the base material to be welded is 15-22 mm, and the welding wire used for the CMT welding gun and the MIG welding gun is selected according to the material of the base material to be welded; the welding wire is an ordinary welding wire or a high-strength steel welding wire with a copper-plated surface. When using an ordinary welding wire, the welding wire is subjected to pre-welding treatment such as degreasing, pickling and drying.

3. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S1, the joint of the base material to be welded is cleaned by alcohol or acetone.

4. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S3, the diameter of the welding wire of the CMT welding gun is 1.2 mm, the current of the welding wire is 100-150 A, the arc voltage is 16-20 V, and the wire feeding speed is 4-8 m / min.

5. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S3, the coaxial shielding gas of the CMT welding gun is argon gas with a purity of 99.99%, and the shielding gas flow rate is 15-25 L / min.

6. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S5, the diameter of the MIG welding gun is 1.2 mm, the current of the welding wire is 150-220 A, the arc voltage is 20-30 V, and the wire feeding speed is 4-8 m / min.

7. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S5, the distance between the welding wire used by the MIG welding gun and the upper surface of the base material to be welded is 1-2 mm.

8. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1 is characterized in that: In step S5, the coaxial shielding gas of the MIG welding gun is argon gas with a purity of 99.99%, and the shielding gas flow rate is 15-25 L / min.

9. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1, characterized in that: In step S6, the power of the laser is 5-10 kW, the laser spot diameter is 0.4-0.6 mm, the laser defocus is 0 mm, and the welding speed is 0.5-1.0 m / min.

10. The CMT primer laser arc hybrid welding process for butt jointing according to claim 1, characterized in that: In step S6, the two heat sources of laser welding and MIG arc welding form one heat source and a common molten pool, and the welding wire is fed into the surface of the molten pool through the MIG welding gun to form a short-circuit transition. In the case of high current, it is a jet transition without arc interruption.

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