Dual-energy different-beam laser indirect electric arc hybrid welding method for super-thick-wall component

Abstract

The invention provides a double-energy different-beam laser indirect electric arc hybrid welding method for an ultra-thick-wall component, a hybrid heat source comprises a common single laser beam, a scanning laser beam and one or one group of indirect electric arcs which are arranged in sequence, and the welding method comprises the following steps: before welding, forming a groove with a certain angle and a penetrating gap on the ultra-thick-wall component; the groove of the super-thick-wall component is sequentially divided into a truncated edge penetrating area, a middle expansion area and a remaining coverage area except the truncated edge penetrating area, the middle expansion area and the remaining coverage area in the thickness direction from bottom to top; during welding, one-time welding forming of the super-thick-wall component is achieved through cooperation of multiple heat sources; wherein the common single laser beam is used for completely penetrating through the truncated edge penetrating area so as to carry out penetrating welding on a gap at the truncated edge; the scanning laser beam is used for welding the side wall of the middle expansion area so as to effectively fuse the middle side wall; the indirect arc is used for full-coverage welding and effective filling of the remaining coverage area. The technical problem of single-pass welding bottleneck of the super-thick-wall component with the thickness being 25 mm or above is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite welding, and in particular to a dual-energy different-beam laser indirect arc composite welding method for ultra-thick-walled components. Background Art

[0002] Indirect arc welding is a novel welding heat source mode that uses discharges between multiple wires to form an indirect arc. Combining a high-energy laser beam with the indirect arc can achieve superior fill performance compared to conventional laser arc hybrid welding. Therefore, while maintaining constant laser power and blunt edges, laser arc hybrid welding can completely fill a larger groove with a single weld, further increasing the maximum weldable thickness per pass. According to data, the maximum weldable thickness per pass for laser arc hybrid welding is approximately 20 mm, while laser arc hybrid welding can exceed this limit.

[0003] However, even laser indirect arc hybrid welding (LAIHW) encounters a bottleneck when the thickness of the weld increases beyond 25 mm. While deepening the groove depth can address laser penetration, increasing the arc power between multiple wires to increase wire deposition and ensure a full weld is limited. For example, exceeding the inter-wire current limit can lead to fuse instability or even discharge explosion, seriously affecting weld formation, joint performance, and microstructure. On the other hand, reducing the groove angle to reduce filler metal requirements can lead to sidewall incomplete fusion defects due to the difficulty of the laser and arc heat sources to fully cover the groove. Maintaining the groove dimensions and increasing the blunt edge thickness requires higher laser line energy for greater penetration in a single pass. However, this results in more intense thermal reactions within the keyhole, increased thermal gradients in the molten pool, and increased amounts of interfering materials such as plume, smoke, and spatter. This can lead to a series of welding manufacturing issues, including increased porosity, decreased forming stability, reduced penetration conversion efficiency, increased weld distortion, and weakened joint performance. Therefore, the technical bottlenecks of single-pass welding of ultra-thick-walled components over 25 mm in thickness urgently need to be addressed. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components, which solves the technical problem of the bottleneck of single-pass welding of ultra-thick-walled components with a thickness of more than 25 mm.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows: The present invention provides a dual-energy different-beam laser indirect arc composite welding method for ultra-thick-walled components. The dual-energy different-beam laser indirect arc composite heat source includes one ordinary single laser beam, one scanning laser beam and one or one group of indirect arcs arranged in sequence. The welding method includes the following steps: before welding, a groove with a certain angle and a penetration gap is first opened on the ultra-thick-walled component; the groove of the ultra-thick-walled component is divided into a blunt edge penetration area, a middle expansion area and a remaining coverage area from bottom to top along the thickness direction; during welding, one-time welding and double-sided forming of the ultra-thick-walled component is achieved through the synergistic action of three heat sources; wherein, the ordinary single laser beam is used to completely penetrate the blunt edge penetration area to perform penetration welding on the gap at the blunt edge; the scanning laser beam is used to weld the side wall of the middle expansion area to effectively fuse the middle side wall; and the indirect arc is used to perform full coverage welding and effective filling on the remaining coverage area.

[0006] Furthermore, the indirect arc, the scanning laser beam and the ordinary single laser beam are arranged in sequence along the welding direction.

[0007] Furthermore, the indirect arc uses double wires or multiple wires, and can discharge only between the welding wires, or can discharge simultaneously between the welding wires and between the welding wire and the base material.

[0008] Furthermore, the groove adopts a "Y"-shaped groove or a "U"-shaped groove with a penetration gap.

[0009] Furthermore, the gap width at the blunt edge of the groove is less than 1 mm.

[0010] Furthermore, the thickness of the blunt edge penetration area ranges from 10 to 20 mm.

[0011] Furthermore, the thickness of the middle expansion area ranges from 2 to 15 mm.

[0012] Furthermore, the thickness of the remaining coverage area ranges from 5 to 15 mm.

[0013] Furthermore, the scanning laser beam can be replaced by a "large spot" laser beam with a diameter of 2-8 mm.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention uses three heat sources to weld three sections of the ultra-thick-walled component in the thickness direction, thereby effectively breaking through the weldable thickness limit of laser arc hybrid welding without increasing the energy of a single laser beam line, and to a certain extent reducing the dependence on ultra-high power lasers when welding ultra-thick-walled components.

[0015] 2. The present invention supports the use of a small-angle groove. Although the groove depth is increased, the metal filling amount can be better controlled, so there is no need to increase the welding wire deposition amount by increasing the arc power. It effectively avoids the phenomenon of fuse instability caused by excessive inter-wire current, or even discharge explosion, which affects the weld formation, joint performance and organizational structure.

[0016] 3. The present invention does not rely on simply increasing the energy of a single laser line to achieve greater penetration, will not intensify the thermal reaction in the keyhole, and can effectively suppress the increase in the thermal field gradient of the molten pool and the large-scale production of interfering substances such as plume, smoke, and spatter. Therefore, it can easily solve a series of welding manufacturing problems caused by high-power laser welding, such as increased porosity tendency, decreased forming stability, reduced penetration conversion efficiency, increased welding deformation, and weakened joint performance.

[0017] 4. The scanning laser welding used in the present invention can effectively solve the problem of side wall unfusion defects caused by the difficulty of using conventional laser arc composite heat source to completely cover the groove area during small-angle groove welding.

[0018] 5. This invention supports the use of a shallow "Y"-shaped groove or a narrow-gap "U"-shaped groove with a certain angle. During welding, the cross-section of the molten pool presents a uniform transition from wide at the top to narrow at the bottom, which helps to float process-related pores and reduce pore defects during welding. Furthermore, because the keyhole tends to expand outward due to the internal metal vapor pressure during welding, this uniform transition of the molten pool, which is "wide at the top and narrow at the bottom," creates a "trumpet-shaped" trend within the laser keyhole, with the opening widening upward. This facilitates the release of ejected material from the keyhole during laser welding of ultra-thick-walled components, thereby reducing laser energy loss and fluctuations. Therefore, it is effective in improving the stability of laser welding of ultra-thick-walled components.

[0019] 6. The indirect arc used in the present invention can discharge only between the welding wires, or can discharge simultaneously between the welding wires and between the welding wires and the base material. Therefore, the indirect arc can better control the overheating of the molten pool and effectively improve the welding wire deposition amount and deposition efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 Schematic diagram of the structure when welding using the welding method of the present invention; wherein the direction of the arrow indicates the welding direction; Figure 2 It is a right side view schematic diagram of welding using the welding method of the present invention.

[0022] mark: 1-Ordinary single laser beam; 2-Scanning laser beam; 3-Indirect arc; 4-Blunt edge penetration area; 5-Middle extension area; 6-Remaining coverage area. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] This embodiment provides a dual-energy laser indirect arc hybrid welding method for ultra-thick wall components. Figure 1-2 As shown, the dual-energy different-beam laser indirect arc composite heat source includes one or one group of indirect arcs 3, one scanning laser beam 2 and one ordinary single laser beam 1 arranged in sequence along the welding direction; the welding method includes the following steps: Before welding, a Y-shaped or U-shaped groove with a certain angle and a penetration gap is formed on the ultra-thick-walled component, where the cross-sectional area of the groove is smaller than the maximum fill volume for arc welding. The groove of the ultra-thick-walled component is divided from bottom to top along the thickness direction into a blunt-edge penetration area 4, a middle expansion area 5, and a remaining coverage area 6. During welding, the coordinated action of three heat sources is used to achieve double-sided forming of ultra-thick-walled components through one-time welding; wherein, the ordinary single laser beam 1 is used to completely penetrate the blunt edge penetration area 4 to perform penetrating welding on the gap at the blunt edge; the scanning laser beam 2 is used to weld the side walls of the middle expansion area 5 to effectively fuse the middle side walls; the indirect arc 3 is used to perform full coverage welding and effective filling of the remaining coverage area 6.

[0025] The gap width at the blunt edge of the groove is generally less than 1mm; the thickness of the blunt edge penetration area 4 ranges from 10-20mm; the thickness of the intermediate extension area 5 ranges from 2-15mm; and the thickness of the remaining coverage area 6 ranges from 5-15mm. Furthermore, the gap width at the upper end of the groove is generally less than 10mm (greater than the blunt edge gap); the single-side angle of a "U"-shaped groove is 0-5°, and the single-side angle of a small V (upper Y) groove is 4-15°. The single-side angle is the angle between the groove surface and the vertical line. The thickness range of each area can be determined based on the laser spot diameter, the scanning laser's swing radius, and the arc's spread coverage.

[0026] In addition, it should be noted that the present invention limits the specific application scenarios of this method, that is, its application in scenarios of small angles, high depths (V parts) and narrow gap grooves of ultra-thick-walled components (above 25 mm).

[0027] Specific example description: 1. Three-heat source zone welding process based on "Y" type groove 1. Arrangement order of composite heat sources Composite heat source: It is composed of 1 ordinary single laser beam, 1 scanning laser beam and 1 indirect arc; Along the welding direction, they are: indirect arc 3, scanning laser beam 2 and ordinary single laser beam 1.

[0028] 2. Slope opening and area division A small-angle "Y"-shaped groove is opened on a 25mm thick ultra-thick-walled component, leaving a 0.5mm gap at the blunt edge, and ensuring that the corresponding groove cross-sectional area is smaller than the maximum fillable amount / area of the arc.

[0029] Along the groove thickness direction from bottom to top, it is divided into: Blunt edge penetration area (thickness 16mm), the penetration gap at the bottom of the groove; The middle expansion area (3mm thickness) is located in the fusion area in the middle of the groove; The remaining covering area (thickness 6mm) is located in the area to be filled above the groove.

[0030] 3. Three heat source collaborative welding Ordinary single laser beam: Focused on blunt edge penetration area 4, penetrating 16mm blunt edge to form penetrating welding; Scanning laser beam: Scan the middle expansion area 5 horizontally to effectively fuse the middle side wall; in addition, the gap width at the upper end of the groove is generally less than 10mm, and in this case, a "large spot" laser beam with a diameter of 2-8mm can be used instead to achieve the same effect.

[0031] Indirect arc: uses two wires and discharges only between the wires, filling and covering the remaining area6.

[0032] 2. Welding process based on “U” groove with gap 1. Arrangement order of composite heat sources Composite heat source: It is composed of 1 ordinary single laser beam, 1 scanning laser beam and 1 indirect arc; Along the welding direction, they are: indirect arc 3, scanning laser beam 2 and ordinary single laser beam 1.

[0033] 2. Slope opening and area division Processing a narrow-gap, small-angle "U"-shaped groove on a 28mm thick component, with a blunt edge gap of 0.7mm, corresponds to a groove cross-sectional area that is smaller than the maximum fillable volume / area of the arc; Along the groove thickness direction from bottom to top, it is divided into: Blunt edge penetration area (thickness 10mm), the penetration gap at the bottom of the groove; The middle expansion area (8mm thickness) is located in the fusion area in the middle of the groove; The remaining covering area (thickness 10mm) is located in the area to be filled above the groove.

[0034] 3. Three heat source collaborative welding Ordinary single laser beam: Focused on blunt edge penetration area 4, penetrating 10mm blunt edge to form penetrating welding; Scanning laser beam: Scans the middle expansion area 5 horizontally to effectively fuse the middle sidewalls. In addition, the gap width at the upper end of the groove is generally less than 10mm. In this case, a "large spot" laser beam with a diameter of 2-8mm can be used instead to achieve the same fusion effect. Indirect arc: uses three wires and can discharge simultaneously between the wires and between the wire and the base material, filling and covering the remaining area6.

[0035] The above method uses three heat sources, namely ordinary single laser beam, scanning laser beam and indirect arc, to weld three sections in the thickness direction of ultra-thick-walled components. Combined with the design of small-angle "Y"-shaped or narrow-gap "U"-shaped groove, without increasing the linear energy of a single laser beam, it not only breaks through the weldable thickness limit of laser arc hybrid welding and reduces the dependence on ultra-high power lasers, but also avoids overheating of the molten pool by controlling the metal filling amount. At the same time, scanning laser welding is used to solve the problem of unfused side walls of small-angle grooves. The groove form makes the cross-section of the molten pool conducive to the floating of process-related pores, reducing the linear energy input to reduce welding stress and deformation, and effectively solving a series of problems such as pores and poor forming stability in high-power laser welding.

[0036] At the same time, the indirect arc, scanning laser beam, and ordinary single laser beam are arranged in sequence along the welding direction, achieving efficient full-thickness welding of ultra-thick-walled components through a synchronized and coordinated spatially partitioned heat input mode: A high-energy-density ordinary single laser beam at the front end first penetrates the blunt edge area to form a through-hole molten pool, laying the foundation for subsequent processing; the central scanning laser beam simultaneously scans the middle of the groove horizontally, using the beam swing to melt the metal on both sides, eliminating the sidewall unfused defects of the small-angle groove; the rear indirect arc is located adjacent to the welded area and simultaneously fills the remaining groove. Its thermal field is superimposed with the preceding laser, completing metal filling through a large deposition capacity while stabilizing the molten pool and avoiding overheating fluctuations and the resulting series of problems. At the same time, the indirect arc is not a simple discharge between the wire and the base material as in traditional arc welding, so it can better control the overheating of the molten pool and effectively improve the deposition volume and deposition efficiency of the welding wire.

Claims

1. A dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick wall components, characterized in that: The dual-energy different-beam laser indirect arc composite heat source includes one ordinary single laser beam, one scanning laser beam and one or one group of indirect arcs arranged in sequence. The welding method includes the following steps: Before welding, a groove with a certain angle and penetration gap is opened on the ultra-thick wall component; Dividing the groove of the ultra-thick-walled component into a blunt edge penetration area, a middle expansion area and a remaining covering area from bottom to top along the thickness direction; During welding, the synergistic effect of three heat sources enables the double-sided forming of ultra-thick wall components through one-time welding; Among them, the ordinary single laser beam is used to completely penetrate the blunt edge penetration area to perform penetration welding on the gap at the blunt edge; the scanning laser beam is used to weld the side walls of the middle expansion area to effectively fuse the middle side walls; the indirect arc is used to fully cover the remaining coverage area and effectively fill it.

2. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1 is characterized in that: The indirect arc, the scanning laser beam and the ordinary single laser beam are arranged in sequence along a welding direction.

3. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The indirect arc uses double wires or multiple wires, and can discharge only between the welding wires, or can discharge simultaneously between the welding wires and between the welding wire and the base material.

4. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The groove adopts a "Y"-shaped groove or a "U"-shaped groove with a penetration gap.

5. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The gap width at the blunt edge of the groove is less than 1 mm.

6. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The thickness of the blunt edge penetration area ranges from 10 to 20 mm.

7. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The thickness of the middle expansion area ranges from 2 to 15 mm.

8. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, characterized in that: The thickness of the remaining covered area is in the range of 5-15 mm.

9. The dual-energy different-beam laser indirect arc hybrid welding method for ultra-thick-walled components according to claim 1, wherein the scanning laser beam can be replaced by a "large spot" laser beam with a diameter of 2-8 mm.

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