A method for laser wire filler welding of dot rings

Abstract

This invention discloses a spot-and-ring laser filler wire welding method, comprising the following steps: cleaning the surface and bevel of the welding plate, and fixing the welding plate on a welding fixture; using a circular spot and an annular spot as a composite heat source for narrow-gap multi-layer filler wire welding of the welding plate; adjusting the defocusing amount, setting the diameter of the circular spot, and setting the diameter of the annular spot; setting the power of the circular spot and the power of the annular spot; setting the welding speed and the wire feeding speed; starting the welding system to perform welding, selecting the number of welding passes until the welding plate completes the butt welding. This invention uses a circular spot and an annular spot as a composite heat source for narrow-gap multi-layer filler wire welding. The circular spot is used to melt the filler wire to perform laser filler wire welding, and the annular spot is used to heat the sidewalls, preventing sidewall melting defects. This can avoid sidewall incomplete fusion defects during narrow-gap welding of thick plates.

Description

Technical Field

[0001] This invention relates to the field of thick plate welding technology, and in particular to a spot ring laser filler wire welding method. Background Technology

[0002] Thick plate structures are widely used in high-end equipment manufacturing industries such as nuclear power, shipbuilding, and petrochemicals, and welding is the primary manufacturing method for thick plate structures. Traditional welding technology using electric arcs as heat sources generates significant welding stress during component connection, leading to deformation of large structural parts and severely impacting the manufacturing quality of high-end equipment. In recent years, efficient welding methods using lasers as heat sources have been gradually applied in the welding field. Due to the high energy density of laser heat sources and low welding heat input, welding stress is greatly reduced, and welded structural deformation is minimized, making it applicable to the precision manufacturing of modern high-end equipment.

[0003] Current laser welding technologies typically use a single laser beam as the heat source, ensuring the formation characteristics of narrow weld seams. Using laser narrow-gap welding, the welding wire can be melted and filled into the bevel of thick plates, achieving plate joining. Compared to traditional arc welding, welding stress and deformation are significantly reduced. However, the excessively narrow laser heat field prevents the laser beam from reaching the sidewall region of the thick plate bevel during narrow-gap welding, thus failing to melt the sidewall and causing gaps between the weld filler metal and the sidewall, resulting in sidewall incomplete fusion defects that severely affect the quality of the weld joint. Therefore, there is an urgent need in this field for a laser welding method that retains the advantages of laser narrow-gap welding while overcoming the occurrence of welding defects.

[0004] Therefore, those skilled in the art are dedicated to developing a spot-ring laser filler wire welding method that, while maintaining the characteristics of gap welding, can avoid the occurrence of sidewall non-fusion defects and realize single-pass multi-layer laser narrow gap welding in a narrow bevel of thick plate. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is: how to solve the problem of sidewall incomplete fusion defects that easily occur in laser ultra-narrow gap welding, and optimize the quality of the welded joint.

[0006] To achieve the above objectives, the present invention provides a spot ring laser filler wire welding method, characterized by comprising the following steps:

[0007] Step 1: Clean the surface and bevel of the welding plate, and fix the welding plate on the welding fixture;

[0008] Step 2: A circular spot and an annular spot are used as a composite heat source for narrow-gap multilayer filler wire welding of the welding plate;

[0009] Step 3: Adjust the defocus amount, set the diameter of the circular dot spot, and set the diameter of the annular spot;

[0010] Step 4: Set the power of the circular spot and the power of the annular spot;

[0011] Step 5: Set the welding speed and the wire feeding speed;

[0012] Step 6: Start the welding system to perform welding, select the number of welding passes until the welding plates are butt welded.

[0013] Furthermore, in step 2, the circular dot light spot and the annular light spot are arranged coaxially.

[0014] Furthermore, in step 2, the circular dot light spot is arranged in front, and the annular light spot is arranged behind the circular dot light spot.

[0015] Furthermore, in step 2, the annular light spot is arranged in front, and the circular dot light spot is arranged behind the annular light spot.

[0016] Furthermore, in step 3, the diameter of the circular dot light spot is set to 0.1-2.0 mm.

[0017] Furthermore, in step 3, the outer diameter of the annular light spot is set to 3.0-6.0 mm.

[0018] Furthermore, in step 4, the power of the circular spot is set to 1-10kW.

[0019] Furthermore, in step 4, the power of the annular light spot is set to 1-5kW.

[0020] Furthermore, in step 5, the welding speed is set to 0.2-2.0 m / min.

[0021] Furthermore, in step 5, the wire feeding speed of the welding wire is set to 1.0-10 m / min.

[0022] This invention proposes a spot-ring laser filler wire welding method, employing a circular spot and an annular spot as a composite heat source for narrow-gap multi-layer filler wire welding. The circular spot melts the welding wire for laser filler wire welding, while the annular spot melts the sidewalls, preventing sidewall melting defects and avoiding sidewall incomplete fusion defects during thick plate narrow-gap welding. Depending on different process requirements, laser beam combinations such as front annular and rear spot, coaxial spot and ring, or front spot and rear annular can be selected, and the spatial positions of the two light sources can be arranged. Front annular and rear spot can achieve preheating of the welding plate and sidewall fusion, coaxial spot and ring can reduce the weld pool size, and front spot and rear annular can achieve slow cooling after welding. By changing the spatial positions of the two spots, welding preheating effect, sidewall fusion effect, control of weld pool size, and slow cooling effect after welding can be added, influencing the welding quality and optimizing the quality of the welded joint.

[0023] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a preferred embodiment of the laser filler wire welding method for the front ring and rear point of the present invention;

[0025] Figure 2 This is a schematic diagram of a preferred embodiment of the laser filler wire welding method for front point and rear ring of the present invention;

[0026] Figure 3 This is a schematic diagram of a preferred embodiment of the point ring coaxial laser filler wire welding method of the present invention;

[0027] Figure 4 This is a cross-sectional schematic diagram of the laser filler wire welding process at the front ring and rear point according to a preferred embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the cross-sectional effect of the laser filler wire welding head at the front ring and rear point of a preferred embodiment of the present invention.

[0029] Among them, 1-welding wire, 2-spot beam, 3-ring beam, 4-transition fillet between weld surface and bevel sidewall, 5-high temperature droplet, 6-solidified weld, 7-welding pool, 8-previous weld, 9-substrate, 10-welding plate bevel, 11-sidewall fusion zone. Detailed Implementation

[0030] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0031] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0032] The test base material in this embodiment was 10CrNi3MoV steel plate with dimensions of 300mm×150mm×30mm. The joint type was a single-sided butt joint with a bevel, a blunt edge of 5.0mm, a root spacing of 3.5mm, a bevel angle of 2.5°, and a 1.2mm diameter WM960s welding wire. The butt welding of the plates was completed through 12 passes.

[0033] In this embodiment, a 5.0mm blunt edge is first welded using a non-pitched dot ring laser to achieve the root pass. Figure 3 As shown, the laser inner ring power is 5 kW, the outer ring power is 1.5 kW, the welding speed is 1.0 m / min, the outer diameter of the ring beam is 3.5 mm, the inner diameter of the ring beam is 1.0 mm, and the diameter of the spot beam is 1.0 mm. Initial filler wire welding is then achieved using a welding configuration where the front beam is a ring beam and the rear beam is a spot beam. Figure 1 , Figure 4 As shown, the outer diameter of the ring beam is 4.0 mm, the inner diameter is 2.0 mm, the diameter of the spot beam is 2.0 mm, the distance between the two beams is 4.0 mm, and the angle between the two laser beams and the workpiece is 85°. High-purity argon gas is used for protection at a flow rate of 20 L / min, the wire feed speed is 5.0 m / min, the laser power of the ring beam before the laser is 4 kW, the laser power of the spot beam after the laser is 4 kW, and the welding speed is 0.5 m / min.

[0034] When filling the narrow gap groove with a filler thickness of 15mm or more, and in this experiment, the fifth filler weld was performed, a welding method using a point beam as the front beam and a ring beam as the rear beam was adopted to achieve subsequent filler wire welding and capping welding. Figure 2 As shown, the outer diameter of the ring beam is 5.0 mm, the inner diameter is 2.5 mm, the diameter of the spot beam is 2.0 mm, the distance between the two beams is 6.0 mm, and the angle between the two laser beams and the workpiece is 85°. High-purity argon gas is used for protection, with a gas flow rate of 20 L / min, a wire feed speed of 5.0 m / min, a laser power of 6 kW for the ring beam before the laser beam, a laser power of 1.5 kW for the spot beam after the laser beam, and a welding speed of 0.4 m / min.

[0035] After welding, X-ray flaw detection showed that the weld quality was Grade 1. The entire welded joint was sampled and subjected to tensile mechanical property testing, which showed that the performance reached more than 90% of the base material.

[0036] In the narrow-gap bevel of thick plates, the initial multi-layer filler welding uses a light source with a ring beam for melting in the front and a point beam for the rear, as shown in the example. Figure 1 , Figure 4 As shown, it can effectively cover the sidewall and weld toe. The front beam, as the light source for melting the sidewall and the weld toe of the previous weld, heats the sidewall and the surface near the weld toe through heat conduction welding, gradually heating the sidewall and weld to melt the sidewall and the previous weld to form a molten pool. The rear beam, as the main light source for melting the welding wire, can effectively cover the welding wire to ensure its melting and transition. After the point light source melts the welding wire to form molten droplets, the molten metal droplets transition into the molten pool formed by the front beam, achieving the filling of the narrow gap bevel. Since the point light source is only responsible for melting the welding wire, it can achieve filling welding with a large wire feed. Furthermore, because the front beam ring light source melts the weld toe and the base material, the surface of the molten pool near the weld toe smoothly transitions to the surface of the narrow gap bevel sidewall under the action of laser recoil pressure, allowing the subsequent filling molten metal droplets to spread smoothly near the sidewall surface, effectively solving the problem of sidewall incomplete fusion caused by poor wettability of molten metal droplets. Figure 5 As shown.

[0037] When the narrow gap bevel is filled to a remaining height of 10-15mm, the welding heat accumulation is significant, making the weld center more prone to cracking under rigid restraint. Simultaneously, due to the increased sidewall temperature, welding spatter is more likely to adhere to the sidewall. If a front-ring-rear-point welding method is used, where the ring beam melts the weld toe and the point beam melts the welding wire, the method of melting the sidewall spatter solely through the molten wire droplets easily leads to incomplete fusion porosity at the spatter location. Conversely, the high-temperature sidewall increases the solidification time of the molten metal droplets, allowing them to spread more smoothly near the sidewall surface. Therefore, a welding method using a front beam as a point source and a rear ring beam is preferable. Figure 3 As shown, the point beam melts the welding wire to form a molten metal pool, achieving welding filling within the gap. The ring light source melts the already formed molten pool area and the sidewall area. By extending the solidification time of the molten pool, bubbles within the pool float to the surface. Furthermore, by controlling the ring beam energy to be 20%-25% of the front beam, the solidification time of the upper surface area of ​​the molten pool is increased. This facilitates the feeding of easily cracked areas by the liquid metal on the surface of the molten pool, effectively improving crack formation and solving the problem of incomplete fusion on the sidewall caused by porosity. Simultaneously, because the rear beam uses a ring spot, the energy distribution within the narrow gap groove is more uniform than with the point beam. Therefore, the weld depth-to-width ratio is smaller, resulting in a weld with better flatness and more uniform formation than the initial narrow gap filling weld. Figure 5 As shown.

[0038] This embodiment includes the following steps:

[0039] Step 1: Before welding, clean the edges of the test plate using an angle grinder or grinder. Clean the test plate with ethanol and acetone to prevent dust and oil from affecting the welding process. Then clamp the test plate together with the blunt edges aligned, ready for laser welding.

[0040] Step 2: A circular spot and an annular spot are used as a composite heat source for narrow-gap multilayer filler wire welding; the circular spot is used to melt the welding wire to perform laser filler wire welding, and the annular spot is used to heat the sidewall to prevent the occurrence of sidewall incomplete fusion defects.

[0041] Step 3: Adjust the defocus amount to control the laser spot diameter. Set the diameter of the circular spot to 0.1-2.0mm and the outer diameter of the annular spot to 3.0-6.0mm.

[0042] Step 4: Set the laser power. Set the power of the circular spot to 1-10kW and the power of the ring spot to 1-5kW.

[0043] Step 5: Set the welding speed to 0.2-2.0 m / min, the distance between the two beams (front ring and rear point) to 2.0-4.0 mm, the outer diameter of the ring spot to 3.0-6.0 mm, the inner diameter to 2.0-4.0 mm, and the angle between the light source and the workpiece to 75-90°. The diameter of the subsequent beam point source is 0.1-2.0 mm, the angle between the light source and the workpiece is 75-90°, the wire diameter is 0.8-1.6 mm, and the angle between the wire and the workpiece is 45-60°. The wire feed speed... The speed is set to 1-10 m / min; the distance between the two beams (front point and rear ring) is set to 4-8 mm; the front beam is a point source with a beam diameter of 0.1-2.0 mm and an angle between the source and the workpiece of 75-90°; the rear beam is a ring source with an outer diameter of 3-6 mm, an inner diameter of 2-4 mm, an angle between the source and the workpiece of 75-90°; the wire diameter is set to 0.8-1.6 mm and an angle between the wire and the workpiece of 15-45°; and the wire feeding speed is set to 1-10 m / min.

[0044] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method of point-arc laser wire fill welding, characterized by, Includes the following steps: Step 1: Clean the surface and bevel of the welding plate, and fix the welding plate on the welding fixture; Step 2: A circular spot and an annular spot are used as a composite heat source for narrow-gap multi-layer filler wire welding of the welding plate; the circular spot is used to melt the welding wire to perform laser filler wire welding, and the annular spot melts the sidewall; during welding, a 5.0mm blunt edge deep penetration welding is first performed using a spot-ring laser without spacing to achieve root pass welding, and then an initial filler wire welding is performed using a welding method with the front beam as an annular beam and the rear beam as a spot beam; when the narrow gap bevel is filled by more than 15mm, the subsequent filler wire welding and cover pass welding are performed using a welding method with the front beam as a spot beam and the rear beam as an annular beam. Step 3: Adjust the defocus amount, set the diameter of the circular dot spot, and set the diameter of the annular spot; Step 4: Set the power of the circular spot and the power of the annular spot; Step 5: Set the welding speed and the wire feeding speed; Step 6: Start the welding system to perform welding, select the number of welding passes until the welding plates are butt welded.

2. The point laser welding method of claim 1, wherein, In step 3, the diameter of the circular spot is set to 0.1-2.0 mm.

3. The point laser welding method of claim 1, wherein, In step 3, the outer diameter of the annular light spot is set to 3.0-6.0 mm.

4. The point laser welding method of claim 1, wherein, In step 4, the power of the circular spot is set to 1-10 kW.

5. The point laser welding method of claim 1, wherein, In step 4, the power of the annular light spot is set to 1-5kW.

6. The point laser welding method of claim 1, wherein, In step 5, the welding speed is set to 0.2-2.0 m / min.

7. The point laser welding method of claim 1, wherein, In step 5, the wire feeding speed of the welding wire is set to 1.0-10 m / min.

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