A laser-GMAW full penetration backing welding method with pre-placed welding wire

Abstract

The present invention relates to a laser-GMAW full-penetration backing welding method with pre-placed welding wire, belonging to the technical field of welding. The technical solution includes the following steps: (1) The workpieces to be welded are processed with bevels, assembled, and tack welded; (2) During welding, welding wire is pre-placed synchronously in the bevel of the workpiece to be welded to fill the assembly gap of the workpiece to be welded; (3) The laser-GMAW hybrid welding method is used for backing welding. The hybrid heat source first melts the pre-placed welding wire, and the molten pool metal fills the gap in the bevel of the workpiece. Under the action of the hybrid heat source of the laser beam and the GMAW arc, full-penetration backing welding is achieved. The present invention can meet the requirements of single-pass full-penetration backing welding under complex working conditions. By means of pre-placing welding wire, the adaptability of welding to working conditions is significantly increased, the precision requirements for pre-welding processing and assembly are reduced, and at the same time, the welding production efficiency is significantly improved, which is beneficial to the application of automated welding.

Description

Technical Field

[0001] The present invention relates to a laser - GMAW full - penetration backing welding method with a pre - placed welding wire, belonging to the field of welding technology. Background Art

[0002] Laser - GMAW hybrid welding combines a laser heat source and an arc heat source in a coaxial or side - axis manner to form a new and highly efficient hybrid heat source acting on the same molten pool. It gives full play to the advantages of laser welding and arc welding while making up for their respective deficiencies, featuring fast welding speed, low heat input, and small post - welding deformation of the workpiece. During the laser - GMAW hybrid welding process, the laser beam penetrates the workpiece to form a stable "keyhole", enabling single - side welding with free forming on the back. When performing backing welding in engineering applications with requirements for full - penetration welds, the welding efficiency and quality can be significantly improved. However, laser - GMAW hybrid welding for backing requires high precision in workpiece processing dimensions and pre - assembly accuracy, which greatly limits its application. For example, in the Chinese patent application No. CN2020112950424, titled "A Method for Single - Side Welding of Ship Thick Plates", a method for laser hybrid welding backing and GMAW (abbreviation for gas metal arc welding) surfacing welding of ship thick plates is disclosed, with the workpiece assembly gap requirement being 0.7 - 0.9 mm.

[0003] To improve the engineering application adaptability of the laser - GMAW welding method, the patent with the authorization announcement number CN113523574B, titled "A Full - Penetration Welding Method for Marine Pipes", first uses a GMAW arc to weld and fill the assembly gap of the marine pipe, and then remelts the first - pass weld using laser - GMAW hybrid welding to achieve full - penetration backing. This method requires two - pass welding to complete the backing weld, which has more complex requirements for equipment performance and functions. Moreover, the welding speed of the first pass is relatively low, seriously affecting the welding production efficiency.

[0004] When using external wire feeding for the laser - arc hybrid welding heat source, generally, it aims to consume the excess heat during the welding process of the hybrid heat source, improve the metal cladding efficiency, reduce the heat input, and minimize the welding deformation without increasing the arc and power. For example, in the patent "Laser - GMA Arc Hybrid Heat Source Wire - Feeding Welding Method" with the application number CN103862177B and the patent "Laser - GMA Arc Hybrid Heat Source Pulse Wire - Feeding Method for Wire - Feeding Welding" with the application number CN113427131A, both use the external wire - feeding method to increase the metal cladding efficiency, improve the weld quality, reduce subsequent multi - layer and multi - pass welding processes, and enhance the welding efficiency. In this case, the external wire - feeding speed used is relatively large, and the wire - feeding position is inside the hybrid - welding molten pool. None of the above measures can improve the adaptability of laser - arc hybrid welding to the workpiece assembly conditions. Summary of the Invention

[0005] The object of the present invention is to provide a laser - GMAW full - penetration root welding method with pre - placed wire, which can be applicable to welding joint forms with poor machining accuracy and a large range of joint gaps, thereby reducing the pre - welding machining man - hours, improving the welding quality, greatly enhancing the production efficiency, and solving the problems existing in the background technology.

[0006] The technical solution of the present invention is as follows:

[0007] A laser - GMAW full - penetration root welding method with pre - placed wire, along the welding direction, the pre - placed wire, the laser beam and the GMAW arc are arranged in sequence, and the laser - GMAW composite heat source is used to achieve full - penetration root welding. It is characterized by including the following steps:

[0008] (1) The workpieces to be welded are processed with grooves, assembled, and tack - welded.

[0009] (2) During welding, pre - placed wire is synchronously placed in the groove of the workpiece to be welded to fill the joint gap of the workpiece to be welded.

[0010] (3) The root welding is carried out by using the laser - GMAW composite welding method. The composite heat source first melts the pre - placed wire, and the molten pool metal fills the gap in the groove of the workpiece. Under the action of the composite heat source of the laser beam and the GMAW arc, full - penetration root welding is achieved.

[0011] In the step (1), the groove form is I - shape or Y - shape, the joint gap b is 0 - 2 mm, the misalignment s is 0 - 2 mm. When it is a Y - shaped groove, the groove angle a is 0 - 75°, and the root face p is 0 - 6 mm.

[0012] In the step (2), the diameter δ of the pre - placed wire is 0.8 - 2.0 mm, and the wire feeding speed Vs is 0.8 - 2.5 times the welding speed.

[0013] In the step (3), the angle α1 between the pre - placed wire and the laser beam is 30 - 90°, and the distance D1 between the pre - placed wire and the laser beam at the bottom of the groove is 0 - 5 mm; the laser - GMAW composite welding includes a laser beam and a GMAW arc. Along the welding direction, the laser beam is in front and the GMAW arc is behind. The angle α0 between the laser and the vertical direction is - 10 - 10°, the angle α2 between the GMAW wire and the laser beam is 20 - 60°, the laser power is 2 - 8 kW, the GMAW welding current is 80 - 320 A, the welding speed V is 500 - 2000 mm / min, the defocus amount is - 5 - 5 mm; the distance D2 between the light and the wire is 0 - 4 mm.

[0014] The present invention improves the adaptability of the laser - GMAW composite root welding to the assembly conditions by reasonably controlling the feeding amount of the pre - placed wire, the angle with the laser beam, and the welding process parameters, etc., and expands the welding application range.

[0015] The beneficial effects of the present invention are as follows: The technical solution of the present invention provides a backing welding method for laser-GMAW hybrid welding, which can meet the requirements of full penetration backing welding in a single pass under complex working conditions. By pre-setting the welding wire, the adaptability of the welding to the working conditions is significantly increased, the precision requirements for pre-welding processing and assembly are reduced, and the welding production efficiency is significantly improved, which is beneficial to the application of automated welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the Y-shaped groove of the workpiece to be welded according to the present invention;

[0017] Figure 2 It is a schematic diagram of the I-shaped groove of the workpiece to be welded according to the present invention;

[0018] Figure 3 It is a schematic diagram of the laser-GMAW hybrid welding position in the second step according to the present invention;

[0019] Figure 4 It is a photo of the weld surface formation in the first embodiment according to the present invention;

[0020] Figure 5 It is a photo of the weld back formation in the first embodiment according to the present invention;

[0021] Figure 6 It is a macroscopic photo of the weld cross-section in the first embodiment according to the present invention;

[0022] Figure 7 It is a photo of the weld surface formation in the second embodiment according to the present invention;

[0023] Figure 8 It is a photo of the weld back formation in the second embodiment according to the present invention;

[0024] Figure 9 It is a macroscopic photo of the weld cross-section in the second embodiment according to the present invention;

[0025] Figure 10 It is a photo of the weld surface formation in the third embodiment according to the present invention;

[0026] Figure 11 It is a photo of the weld back formation in the third embodiment according to the present invention;

[0027] Figure 12 It is a macroscopic photo of the weld cross-section in the third embodiment according to the present invention;

[0028] Figure 13 It is a photo of the weld surface formation in the fourth embodiment according to the present invention;

[0029] Figure 14 It is a photo of the weld back formation in the fourth embodiment according to the present invention;

[0030] Figure 15This is the macroscopic photo of the weld cross-section in the fourth embodiment of the present invention;

[0031] In the figure: 1 is the workpiece to be welded; 2 is the first pre-placed wire; 3 is the laser beam; 4 is the second GMAW wire; a is the groove angle; b is the assembly gap; s is the misalignment; p is the root face height; α0 is the angle between the laser beam and the vertical direction; α1 is the angle between the pre-placed wire and the laser beam; α2 is the angle between the GMAW wire and the laser beam; D1 is the distance between the tip of the pre-placed wire and the laser beam; D2 is the distance between the laser beam and the GMAW wire. Specific implementation manners

[0032] The present invention will be further described below with reference to the accompanying drawings through embodiments.

[0033] A laser-GMAW full-penetration backing welding method with pre-placed wires, in the welding direction, the pre-placed wires, the laser beam and the GMAW arc are arranged in sequence, and the laser-GMAW composite heat source is used to achieve full-penetration backing welding, including the following steps:

[0034] (1) The workpiece to be welded is processed with a groove, assembled, and tack-welded;

[0035] (2) During welding, pre-placed wires are synchronously placed in the groove of the workpiece to be welded to fill the assembly gap of the workpiece to be welded;

[0036] (3) The laser-GMAW composite welding method is used for backing welding. The composite heat source first melts the pre-placed wires, and the molten pool metal fills the gap in the groove of the workpiece, and full-penetration backing welding is achieved under the action of the composite heat source of the laser beam and the GMAW arc.

[0037] In the step (1), the groove form is I-shaped or Y-shaped, the assembly gap b is 0 - 2 mm, the misalignment s is 0 - 2 mm, when it is a Y-shaped groove, the groove angle a is 0 - 75°, and the root face p is 0 - 6 mm.

[0038] In the step (2), the diameter δ of the pre-placed wire is 0.8 - 2.0 mm, and the wire feeding speed Vs is 0.8 - 2.5 times the welding speed.

[0039] In the step (3), the angle α1 between the pre-placed wire and the laser beam is 30 - 90°, and the distance D1 between the pre-placed wire and the laser beam at the bottom of the groove is 0 - 5 mm; the laser-GMAW composite welding includes a laser beam and a GMAW arc. In the welding direction, the laser beam is in front and the GMAW arc is behind. The angle α0 between the laser and the vertical direction is -10 - 10°, the angle α2 between the GMAW wire and the laser beam is 20 - 60°, the laser power is 2 - 8 kW, the GMAW welding current is 80 - 320 A, the welding speed V is 500 - 2000 mm / min, and the defocus amount is -5 - 5 mm; the distance D2 between the laser beam and the wire is 0 - 4 mm.

[0040] Example 1:

[0041] Adopt this technical solution to weld the circumferential butt weld of pipes with a wall thickness of 10 mm and a pipe diameter of 160 mm.

[0042] In step (1), the pipe fitting is opened with a Y-shaped groove, the groove angle is 50°, the blunt edge is 2 mm, the assembly gap is 0.5 mm, the misalignment is 0.5 mm, and tack welding is carried out after assembly;

[0043] In step (2), the diameter δ of the pre-placed welding wire is 1.0 mm, and the wire feeding speed is 1200 mm / min;

[0044] In step (3), the angle α1 between the pre-placed welding wire and the laser beam is 90°, and the distance D1 between the pre-placed welding wire and the laser beam at the bottom of the groove is 3 mm; The pipe fitting is rotated and welded at the downhill position. Along the welding direction, the laser beam is in the front and the GMAW arc is in the back. The angle α0 between the laser and the vertical direction is 0°, and the angle α2 between the GMAW welding wire and the laser beam is 30°; During welding, the laser power is 3.0 kW, the welding current of the GMAW arc is 160 A, the welding speed is 600 mm / min, and the defocus amount is 0 mm. The distance D2 between the light and the wire is 2 mm;

[0045] Figure 4 It is the surface forming photo of the weld in Example 1;

[0046] Figure 5 It is the back forming photo of the weld in Example 1;

[0047] Figure 6 It is the macroscopic photo of the cross section of the weld in Example 1.

[0048] Example 2:

[0049] Adopt this technical solution to weld the circumferential butt weld of pipes with a wall thickness of 4 mm and a pipe diameter of 80 mm.

[0050] In step 1, the pipe fitting is opened with an I-shaped groove, the assembly gap is 1.5 mm, the misalignment is 1.5 mm, and tack welding is carried out after assembly;

[0051] In step 2, the diameter δ of the pre-placed welding wire is 1.6 mm, and the wire feeding speed is 1200 mm / min;

[0052] In Step 3, the angle α1 between the pre-placed welding wire and the laser beam is 90°, and the distance D1 between the pre-placed welding wire and the laser beam at the bottom of the groove is 3 mm; welding is carried out at the downhill position with the pipe fitting rotating. Along the welding direction, the laser beam is in the front and the GMAW arc is in the rear. The angle α0 between the laser and the vertical direction is +5°, and the angle α2 between the GMAW welding wire and the laser beam is 30°; during welding, the laser power is 3.5 kW, the welding current of the GMAW arc is 120 A, the welding speed is 800 mm / min, and the defocus amount is 0 mm. The distance D2 between the light and the wire is 2 mm.

[0053] Figure 7 It is a photo of the weld surface formation in Example 2;

[0054] Figure 8 It is a photo of the weld back formation in Example 2;

[0055] Figure 9 It is a macro photo of the weld cross-section in Example 2.

[0056] Example 3:

[0057] Using this technical solution to weld the butt joint of the splicing plate, the plate thickness is 12 mm, and the butt weld of the flat plate with a size of 150×300 mm.

[0058] Among them, in Step (1), the pipe fitting is opened with a Y-shaped groove, the groove angle is 50°, the blunt edge is 4 mm, the assembly gap is 0.5 mm, the misalignment is 0.5 mm, and tack welding is carried out after assembly;

[0059] In Step (2), the diameter δ of the pre-placed welding wire is 1.4 mm, and the wire feeding speed is 1500 mm / min;

[0060] In Step (3), the angle α1 between the pre-placed welding wire and the laser beam is 60°, and the distance D1 between the pre-placed welding wire and the laser beam at the bottom of the groove is 4 mm; along the welding direction, the laser beam is in the front and the GMAW arc is in the rear. The angle α0 between the laser and the vertical direction is 0°, and the angle α2 between the GMAW welding wire and the laser beam is 25°; during welding, the laser power is 4.5 kW, the welding current of the GMAW arc is 280 A, the welding speed is 1000 mm / min, and the defocus amount is -2 mm. The distance D2 between the light and the wire is 1 mm.

[0061] Figure 10 It is a photo of the weld surface formation in Example 3;

[0062] Figure 11 It is a photo of the weld back formation in Example 3;

[0063] Figure 12 It is a macro photo of the weld cross-section in Example 3.

[0064] Example 4:

[0065] The butt joint of the welded splice plate is adopted in this technical solution. The plate thickness is 6 mm, and it is a butt weld of a flat plate with dimensions of 150×300 mm.

[0066] In step one, the pipe fitting is opened with a V-groove. The assembly gap is 1.5 mm, and the misalignment is 1.5 mm. After assembly, tack welding is carried out.

[0067] In step two, the diameter δ of the pre-placed welding wire is 1.2 mm, and the wire feeding speed is 1500 mm / min.

[0068] In step three, the angle α1 between the pre-placed welding wire and the laser beam is 45°. The distance D1 between the pre-placed welding wire and the laser beam at the bottom of the groove is 4 mm. Along the welding direction, the laser beam is in the front, and the GMAW arc is behind. The angle α0 between the laser and the vertical direction is 0°, and the angle α2 between the GMAW welding wire and the laser beam is 25°. During welding, the laser power is 5.5 kW, the welding current of the GMAW arc is 240 A, the welding speed is 1200 mm / min, and the defocus amount is -2 mm. The distance D2 between the laser and the wire is 3 mm.

[0069] Figure 13 It is a photo of the weld surface formation in Example 4.

[0070] Figure 14 It is a photo of the weld back formation in Example 4.

[0071] Figure 15 It is a macro photo of the weld cross-section in Example 4.

Claims

1. A laser-GMAW full penetration backing welding method with pre-placed wire, in the welding direction, the pre-placed wire, laser beam and GMAW arc are arranged in sequence, and the laser-GMAW is used to form a composite heat source to achieve full penetration backing welding, characterized in that It includes the following steps: (1) The weldment to be welded is processed with a groove, assembled, and tack-welded; (2) During welding, a welding wire is synchronously pre-placed in the groove of the weldment to be welded to fill the assembly gap of the weldment; (3) Laser-GMAW hybrid welding method is used for root pass welding. The hybrid heat source first melts the pre-placed welding wire, and the molten pool metal fills the gap in the groove of the weldment. Under the action of the hybrid heat source of the laser beam and the GMAW arc, full penetration root pass welding is achieved; In the step (2), the diameter δ of the pre-placed welding wire is 0.8 - 2.0 mm, and the wire feeding speed Vs is 0.8 - 2.5 times the welding speed; In the step (3), the angle α1 between the pre-placed welding wire and the laser beam is 30 - 90°, and the distance D1 between the pre-placed welding wire and the laser beam at the bottom of the groove is 0 - 5 mm; The laser-GMAW hybrid welding includes a laser beam and a GMAW arc. Along the welding direction, the laser beam is in front and the GMAW arc is behind. The angle α0 between the laser and the vertical direction is -10 - 10°, the angle α2 between the GMAW welding wire and the laser beam is 20 - 60°, the laser power is 2 - 8 kW, the GMAW welding current is 80 - 320 A, the welding speed V is 500 - 2000 mm / min, and the defocus amount is -5 - 5 mm; The distance D2 between the laser and the wire is 0 - 4 mm.

2. A laser-GMAW full penetration backing welding method with pre-placed welding wire according to claim 1, characterized in that: In the step (1), the groove form is I-shaped or Y-shaped, the assembly gap b is 0 - 2 mm, the misalignment amount s is 0 - 2 mm. When it is a Y-shaped groove, the groove angle a is 0 - 75°, and the root face p is 0 - 6 mm.

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