A method of Y groove welding

Abstract

The application discloses a Y-type groove welding method, which comprises the following steps: a welding groove is formed on a base material to be welded, the front surface of the welding groove is provided with a V-shaped opening, and the back surface of the welding groove is provided with a root face; the base material is placed on a horizontal operation surface, and a welding device is provided, the welding device comprises an AC / DC power supply and a double-wire submerged arc welding trolley, the negative output end of the AC / DC power supply is electrically connected with the rear conductive nozzle of the double-wire submerged arc welding trolley and the base material respectively, the positive output end of the AC / DC power supply is electrically connected with the front conductive nozzle of the double-wire submerged arc welding trolley, welding wires are respectively arranged on the front conductive nozzle and the rear conductive nozzle, and the two welding wires are respectively arranged to contact the one end of the base material, the AC / DC power supply is adjusted to the AC mode, and the two welding wires are simultaneously used to weld the front surface of the welding groove; the AC / DC power supply is adjusted to the DC mode, and the welding wire on the front conductive nozzle is used to weld the back surface of the welding groove. The welding efficiency is high, and the welding quality is good.

Description

Technical Field

[0001] This invention relates to the field of steel plate welding technology, and more particularly to a Y-groove welding method. Background Technology

[0002] In shipbuilding, it is often necessary to weld and assemble two medium-thick base materials, where the thickness H of the base material is...

[0003] For welds ≥12mm, a beveling is required to ensure full penetration. Typically, when 12mm≤H≤24mm, a Y-shaped beveling (i.e., the beveling from top to bottom consists of a V-shaped beveling and a blunt edge) is required at the weld joint of the two base materials to accelerate the deposition rate by increasing the welding current. However, the increase in current is constrained by the following two aspects: (1) The increase in current is constrained by the assembly gap between the base materials. When the assembly gap does not meet the requirements (in GB / T3400-2016 China Shipbuilding Quality Standard, the standard for the assembly gap of submerged arc welding is 0-0.8mm, and the limit is ≤2mm), molten iron is very likely to leak from the gap between the two base materials during welding, leading to weld penetration and welding interruption, which affects the welding quality of the base materials; (2) The increase in welding current will lead to an increase in heat input, which is not conducive to improving the impact toughness of the heat-affected zone of the weld and the base material. The increase in welding current will lead to an increase in heat input, which is not conducive to improving the impact toughness of the heat-affected zone of the weld and the base material. Therefore, constrained by the two factors mentioned above, although the welding wire is allowed to carry a welding current of 800 amps for a φ4.0 diameter wire and 1000 amps for a φ4.8 diameter wire, the standard gap requirement can only be achieved by machined milling or planing workpiece bevels. Shipyards typically use plasma cutting or oxy-fuel flame cutting, which generally results in assembly gaps exceeding the standard gap requirement. Consequently, the actual welding current for the first weld pass does not reach the upper limit allowed by the wire diameter, typically only 450-550 amps. This low-current welding necessitates multiple weld passes to fill the bevel, leading to low welding efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a Y-groove welding method that has high welding efficiency and good welding quality.

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

[0006] A Y-groove welding method is provided, comprising the following steps:

[0007] Step S10: A welding bevel is made on the base material to be welded. The welding bevel has a V-shaped opening on the front side and a blunt edge on the back side.

[0008] Step S20: Place the base material on a horizontal operating surface and provide a welding device, which includes an AC / DC power supply and a twin-wire submerged arc welding carriage. Connect the negative output terminal of the AC / DC power supply to the rear conductive nozzle of the twin-wire submerged arc welding carriage and the base material, respectively. Connect the positive output terminal of the AC / DC power supply to the front conductive nozzle of the twin-wire submerged arc welding carriage. Install welding wires on the front and rear conductive nozzles, respectively, and bring the two welding wires into contact with one end of the base material. Adjust the AC / DC power supply to AC mode and use the two welding wires simultaneously to weld the front side of the welding bevel.

[0009] Step S30: Switch the AC / DC power supply to DC mode and use the welding wire on the front conductive tip to weld the reverse side of the welding bevel.

[0010] As a preferred embodiment of the Y-groove welding method, the distance between the intersection of the welding wire on the front conductive tip and the welding wire on the rear conductive tip and the top of the blunt edge is H1. In step S20, before the two welding wires weld the front side of the welding groove, H1 is adjusted to 7mm. During the welding process of the front side of the welding groove, as the gap of the welding groove increases, H1 is gradually increased, and the maximum value of H1 does not exceed 11mm.

[0011] As a preferred embodiment of the Y-groove welding method, the two ends of the weld groove along its length are respectively groove ends, and the welding of the front side of the weld groove includes the following steps:

[0012] Step S21: Perform tack welding on the two bevel ends respectively to form a first welding area, and perform tack welding on the area between the two bevel ends to form a second welding area.

[0013] As a preferred embodiment of the Y-groove welding method, the length of the first welding zone is L1, where L1 ≥ 100 mm;

[0014] And / or, the length of the second welding area is L2, where L2 ≥ 50 mm.

[0015] As a preferred embodiment of the Y-groove welding method, there are two or more second welding zones, all of which are spaced apart, and the interval between adjacent second welding zones is L3, where 300mm ≥ L3 ≥ 500mm.

[0016] As a preferred embodiment of the Y-groove welding method, the weld thickness of both the first welding zone and the second welding zone is less than 6 mm.

[0017] As a preferred embodiment of the Y-groove welding method, in step S20, two sets of positioning components are provided mounted on the operating surface. The two sets of positioning components are respectively disposed on the side of the base material near the two groove ends. Each set of positioning components includes a support plate and two positioning plates disposed on the side of the support plate near the V-shaped opening. The support plate is flush with the bottom of the V-shaped opening. The positioning welding of the groove ends includes the following steps:

[0018] Step S211: Install the support plate on the side of the operating surface near the bevel end and align the two positioning plates with the welding bevel, and weld and fix the support plate to the side of the base material located at the bevel end;

[0019] Step S212: With the splice seam of the two parent materials as the center, the two positioning plates are inclinedly set on both sides of the splice seam so that a V-shaped groove is formed between the two positioning plates. The inclination direction of the two positioning plates is parallel to the inclination direction of the side wall corresponding to the V-shaped opening. The bottom of the positioning plate is welded and fixed to the support plate.

[0020] Step S213: Perform tack welding inside the bevel end to obtain the first welding area, one end of which extends into the V-groove.

[0021] As a preferred embodiment of the Y-groove welding method, the length of the first welding area extending into the V-groove is L4, where L4 ≥ 50 mm.

[0022] As a preferred embodiment of the Y-groove welding method, before welding the two welding wires to the front of the welding groove, the angle between the welding wire on the front conductive tip and the welding wire on the rear conductive tip is adjusted. The tilt angle of the welding wire on the front conductive tip in the vertical direction is controlled to be α, 5°≥α≥0°, and the tilt angle of the welding wire on the rear conductive tip in the vertical direction is controlled to be β, 22°≥β≥32°.

[0023] As a preferred embodiment of the Y-groove welding method, step S30 includes the following steps: Step S31, retracting the welding wire on the rear conductive nozzle to separate the welding wire on the front conductive nozzle from the welding wire on the rear conductive nozzle, and cutting off the electrical connection between the welding wire on the rear conductive nozzle and the AC / DC power supply.

[0024] Step S32: Flip the base material so that the reverse side of the welding bevel faces upward, and use the welding wire of the front conductive tip to weld to the blunt edge of the bevel.

[0025] The beneficial effects of this invention are as follows: In this Y-shaped groove welding method, AC power and double welding wire are used for welding on the front side of the groove, which can effectively increase the deposition rate, reduce the weld penetration, and prevent burn-through. DC power and single welding wire are used for welding on the back side of the groove, which makes the weld penetration on the blunt edge of the groove greater and helps to ensure full penetration. This results in a flat and aesthetically pleasing double-sided single-pass weld at the groove, which helps to improve welding efficiency and ensure welding quality. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0027] Figure 1 This is a structural diagram of the assembly of the parent material in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the front welding of the Y-shaped groove welding method according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the reverse welding of the Y-shaped groove welding method according to an embodiment of the present invention.

[0030] Figure 4 A top view of the base material and positioning assembly described in an embodiment of the present invention.

[0031] Figure 5 for Figure 4 Sectional view of AA.

[0032] In the picture:

[0033] 1. Base material; 2. AC / DC power supply; 3. Front conductive tip; 4. Rear conductive tip; 5. Wire feed roller; 6. Welding wire; 7. Welding bevel; 701. V-shaped bevel; 702. Blunt edge; 8. Positioning assembly; 801. Support plate; 802. Positioning plate; 9. First branch; 10. Second branch; 11. Wire; 100. First welding zone; 200. Second welding zone. Detailed Implementation

[0034] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] like Figures 1 to 5 As shown, this invention provides a Y-groove welding method, which mainly utilizes the welding assembly of two base materials 1. The method includes the following steps:

[0037] Step S10: A welding bevel 7 is made on the base material 1 to be welded. The front of the welding bevel 7 has a V-shaped opening 701, and the back of the welding bevel 7 has a blunt edge 702. The welding bevel 7 is designed according to the size requirements. The end face (i.e., blunt edge 702) is first processed by oxygen-gas flame cutting, plasma cutting, laser cutting, or machining cutting, and then the bevel (i.e., the inner side of the V-shaped opening 701) is processed. There should be no gaps exceeding 1mm between the two processed surfaces. If there are gaps, the processed surfaces should be ground and repaired or repaired with CO2 welding to make them flat.

[0038] Step S20: Place the base material 1 on a horizontal operating surface and provide a welding device, which includes an AC / DC power supply 2 and a twin-wire submerged arc welding carriage. Connect the negative output terminal of the AC / DC power supply 2 to the rear conductive nozzle 4 of the twin-wire submerged arc welding carriage and the base material 1, respectively. Connect the positive output terminal of the AC / DC power supply 2 to the front conductive nozzle 3 of the twin-wire submerged arc welding carriage. Install welding wires 6 on the front conductive nozzle 3 and the rear conductive nozzle 4, respectively, and bring the two welding wires 6 into contact with one end of the base material 1. Switch the AC / DC power supply 2 to AC mode and use the two welding wires 6 simultaneously to weld the front side of the welding groove 7. The twin-wire submerged arc welding carriage has a wire feeding wheel 5, which feeds the welding wires 6. In practice, wires 11 (e.g., cables) are used to connect the negative output terminal of the AC / DC power supply 2 to the rear conductive nozzle 4 and the base material 1, respectively. Wires 11 are also used to connect the positive output terminal of the AC / DC power supply 2 to the front conductive nozzle 3. The two welding wires 6 are then brought into contact. During welding, the welding wires 6 partially melt, and the molten metal flows from a height into the welding groove 7. The current then splits at the intersection of the two welding wires 6, forming a first branch 9 and a second branch 10, which are then connected to the negative output terminal. The first branch 9 connects the welding wire 6 on the rear conductive nozzle 4 to the negative output terminal, and the second branch... Connection 10 is situated between the base material 1 and the negative output terminal. The first branch 9 melts the welding wire 6 on the front conductive tip 3 and the welding wire 6 on the rear conductive tip 4. The second branch 10 melts both the base material 1 and the welding wire 6 on the front conductive tip 3. Thus, when the first and second branches 9 and 10 are energized, both welding wires 6 and the base material 1 melt simultaneously, increasing the deposition rate of the filler metal in the weld bevel 7. Simultaneously, the current shunting effect reduces the penetration depth, lowers the precision requirements for assembly gaps, and reduces the likelihood of burn-through. This also reduces the actual heat input to the base material 1, effectively meeting its impact toughness requirements. Furthermore, using alternating current to weld the weld bevel 7 in this step avoids magnetic blow and improves the aesthetics of the weld surface when using high currents above 800A.

[0039] Step S30: Switch the AC / DC power supply 2 to DC mode and use the welding wire 6 on the front contact tip 3 to weld the reverse side of the welding groove 7. In this step, DC power is used to weld the reverse side of the welding groove 7, resulting in a weld with the advantages of large penetration depth and flat weld seam.

[0040] In this Y-shaped groove welding method, a single weld is applied to both the front and back sides of the groove 7. The front side of the groove 7 is welded using alternating current and double welding wires 6, which effectively increases the deposition rate, reduces the weld penetration, and prevents burn-through. The back side of the groove 7 is welded using direct current and a single welding wire 6, resulting in a greater weld penetration on the blunt edge 702 of the groove 7, which is beneficial for ensuring complete penetration. This creates a flat and aesthetically pleasing double-sided single-pass weld at the groove 7, which improves welding efficiency and ensures welding quality.

[0041] In this embodiment, the base material 1 is hull structure steel: A, B, D and E; high-strength hull structure steel: AH27, DH27, EH2 hull structure steel, including but not limited to the following steel types: general strength hull structure steel AH27, DH27, EH27, FH27, AH32, DH32, EH32, FH32, AH36, DH36, EH36, FH36, AH40, DH40, EH40, FH40. The welding device has a duty cycle of 100%. The rated welding current is determined by the diameter of the welding wire 6. When using a 3.2mm diameter welding wire 6, the rated welding current is not less than 630A; when using a 4.0mm diameter welding wire 6, the rated welding current is not less than 800A; when using a 4.8 or 5.0mm diameter welding wire 6, the rated welding current is not less than 1000A. It is preferred to use an AC / DC power supply 2 with a rated welding current of 1000A or 1250A.

[0042] In this embodiment, the welding wire 6 on the front conductive nozzle 3 and the welding wire 6 on the rear conductive nozzle 4 are of the same specification to ensure that the welding material on the front and back of the welding groove 7 is the same. This makes the specifications of the components (such as conductive nozzles, gearboxes, and wire feeding wheels) on the two wire feeding mechanisms of the twin-wire submerged arc welding carriage consistent, simplifying the current distribution adjustment of the two branches and improving welding quality. In other embodiments, the specifications of the welding wire 6 on the front conductive nozzle 3 and the welding wire 6 on the rear conductive nozzle 4 can also be different, and the diameter of the welding wire 6 on the front conductive nozzle 3 is larger than that on the rear conductive nozzle 4.

[0043] The distance from the intersection of the welding wire on the front conductive tip and the welding wire on the rear conductive tip to the top of the blunt edge is H1. When the diameters of the welding wire 6 on the front conductive tip 3 and the welding wire 6 on the rear conductive tip 4 are the same, the current distribution for welding the first branch 9 and the second branch 10 is determined by the size of H1. The larger H1 is, the greater the current distributed to the first branch 9. In step S20, before welding the two welding wires to the front of the welding groove, H1 is adjusted to 7mm. During the welding process of the front of the welding groove, H1 is gradually increased as the gap of the welding groove increases, and the maximum value of H1 does not exceed 11mm. When H1 is increased (i.e., the intersection of the welding wire on the front conductive tip and the welding wire on the rear conductive tip is adjusted upward), the total current remains unchanged, but the current on the first branch 9 increases, the welding wire deposition speed is accelerated, the current in the second branch 10 decreases, and the penetration depth decreases, which helps to avoid burn-through and improve the welding quality of the welding groove.

[0044] When the distance H1 between the intersection of the welding wire on the current contact tip and the welding wire on the rear contact tip to the top of the blunt edge is high, such as H1 being 11mm, the current is split between the two welding wires 6 into the first branch 9 and the second branch 10, so that the current in the first branch 9 and the second branch 10 is half of what it was before splitting (i.e., the current ratio in the first branch 9 and the second branch 10 is 1:1). When the intersection of the two welding wires 6 is at a lower position, for example, H1 being 7mm, the current in the first branch 9 is greater than the current in the second branch 10, and the current in the first branch 9 is one-third of the total current. Before welding, it is necessary to set the angle of the welding wire 6, the extension of the welding wire 6 on the contact tip, adjust the two welding wires 6 to contact and intersect on the same straight line, and set the height of the intersection point of the welding wires 6 and the welding direction in advance.

[0045] Specifically, the two ends of the weld groove 7 along its length are the groove ends, and the welding of the front side of the weld groove 7 includes the following steps:

[0046] Step S21: Perform tack welding on the two bevel ends to form the first welding area 100, and perform tack welding in the area between the two bevel ends to form the second welding area 200. By performing tack welding at both ends and non-end positions of the welding bevel 7, the base material 1 is prevented from shifting on the operating surface during welding, thereby further improving the welding quality.

[0047] The length of the first welding area 100 is L1, L1≥100mm, and the length of the second welding area 200 is L2, L2≥50mm. This design ensures that the first welding area 100 and the second welding area 200 have sufficient fixing force to achieve effective positioning of the two welding base materials 1.

[0048] Understandably, some hull structures are quite long. In this case, there are two or more second welding zones 200. All the second welding zones 200 are spaced apart, and the interval between adjacent second welding zones 200 is L3, where 300mm ≥ L3 ≥ 500mm, to ensure that the two base materials 1 are effectively positioned at the non-end position of the splice seam.

[0049] To ensure the structural strength of the first welding zone 100 and the second welding zone 200, the weld thickness of the first welding zone 100 and the weld thickness of the second welding zone 200 are both less than 6 mm.

[0050] In this embodiment, in step S20, two sets of positioning components 8 are also provided, mounted on the operating surface. The two sets of positioning components 8 are respectively disposed on the side of the base material 1 near the two bevel ends. Each set of positioning components 8 includes a support plate 801 and two positioning plates 802 disposed on the side of the support plate 801 near the V-shaped opening 701. In this example, the support plate 801 is a rectangular plate with a length of 150mm, a width of 120mm, and a thickness of 7mm; the positioning plates 802 are rectangular plates with a length of 100mm, a width of 30mm, and a thickness of 7mm. The support plate 801 is flush with the bottom of the V-shaped opening 701. The positioning welding of the bevel ends includes the following steps:

[0051] Step S211: Install the support plate 801 on the side of the operating surface near the bevel end and align the two positioning plates 802 opposite the welding bevel 7, then weld and fix the support plate 801 to the base material 1 on the side of the bevel end. In this step, the upper surface of the support plate 801 is flush with the root of the welding bevel 7 (i.e., the end where the V-shaped opening 701 connects to the blunt edge 702). CO2 welding is used between the support plate 801 and the base material 1 to perform a tack weld between the support plate 801 and the end of the base material 1. The length of the tack weld is not less than 50mm. This design is mainly to control the torsional deformation and gap expansion of the end of the base material 1 during welding, reduce deformation, and avoid terminal cracks.

[0052] Step S212: Centering on the joint of the two base materials 1, two positioning plates 802 are inclinedly placed on both sides of the joint to form a V-groove between them. The inclination direction of the two positioning plates 802 is parallel to the inclination direction of the corresponding sidewall of the V-groove 701. The bottom of the positioning plate 802 is welded and fixed to the support plate 801. In this step, CO2 welding is used between the positioning plate 802 and the support plate 801. By welding the positioning plates 802 at both ends of the welding groove 7 along its length to constrain the flow of molten iron in the pool during welding of the ends of the base materials 1, the consistency between the weld formation at the ends of the base materials 1 and the weld formation in the middle of the welding groove 7 is maintained, which helps to improve the welding quality between the two base materials 1.

[0053] Step S213: Perform tack welding inside the bevel end to obtain the first welding area 100, one end of the first welding area 100 extends into the V-groove.

[0054] Preferably, the length of the first welding area 100 extending into the V-groove is L4, where L4 ≥ 50 mm. This design mainly strengthens the connection structure between the positioning component 8 and the base material 1, increases the thickness of the base plate, and prevents the base plate from being welded through.

[0055] In one embodiment, before welding the two welding wires 6 to the front side of the welding groove 7, the angle between the welding wire 6 on the front conductive tip 3 and the welding wire 6 on the rear conductive tip 4 is adjusted. The vertical tilt angle of the welding wire 6 on the front conductive tip 3 is controlled to be α, where 5° ≥ α ≥ 0°, and the vertical tilt angle of the welding wire 6 on the rear conductive tip 4 is controlled to be β, where 22° ≥ β ≥ 32°. With this design, when welding the reverse side of the welding groove 7 using the welding wire 6 on the front conductive tip 3, it is only necessary to separate the welding wire 6 on the rear conductive tip 4 from the welding wire 6 on the front conductive tip 3; there is no need to readjust the tilt angle of the welding wires 6 on the conductive tips, thus reducing welding auxiliary time.

[0056] Specifically, step S30 includes the following steps: Step S31, retract the welding wire 6 on the rear conductive nozzle 4 so that the welding wire 6 on the front conductive nozzle 3 is separated from the welding wire 6 on the rear conductive nozzle 4, and cut off the electrical connection between the welding wire 6 on the rear conductive nozzle 4 and the AC / DC power supply 2.

[0057] Step S32: Flip the base material 1 so that the reverse side of the welding groove 7 faces upward, and use the welding wire 6 of the front conductive tip 3 to weld to the blunt edge 702 of the groove.

[0058] In practice, the appropriate flux and welding wire grade 6 are selected according to the material of the base material 1 for welding. For general hull structural steels A, B, D, and E with a Charpy V-notch impact temperature requirement of -20℃ and above, as well as high-strength hull structural steels AH27, DH27, EH27, AH32, DH32, EH32, AH36, DH36, and EH36, welding is performed using CHF101 flux and CHW-S3 welding wire 6 (nickel-free). For high-strength hull structural steels FH27, FH32, and FH36 with a Charpy V-notch impact temperature of -40℃, welding is performed using CHF-102A flux and CHW-SG welding wire 6 (containing 0.3-0.35% nickel). For AH40, DH40, EH40, and FH40 steels, welding is performed using S-787TB flux and H-14 welding wire 6. Welding wire specification 6: Generally, welding wire with a diameter of 3.2 / 4.0 / 4.8mm is used for welding, with 4.0 or 4.8mm diameter wire preferred. The welding wire 6 on the front contact tip 3 and the rear contact tip 4 has the same specification. For welding plates thicker than 20mm, 4.8mm diameter welding wire 6 is preferred. The flux must be baked at 350℃ for 1-2 hours before use and stored at 100-150℃. It should be used as needed.

[0059] Based on the thickness of the base material 1, process parameters are pre-set on the submerged arc welding carriage, including the angle and included angle of the welding wire 6.

[0060] The dry extension length of welding wire 6, the centering and intersection of welding wire 6 on the front conductive nozzle 3 and the rear conductive nozzle 4, the height of the contact intersection of welding wire 6, welding current, arc voltage, welding speed, wire feeding speed of the rear welding wire 6, and welding direction.

[0061] For 4.0mm diameter welding wire 6, the welding current is 650-800A, the wire feed speed of welding wire 6 on the rear contact tip 4 is 55-110cm / min, the arc voltage is 34-38V, the wire extension length of welding wire 6 is 32-50mm, and the wire extension length error between welding wire 6 on the front contact tip 3 and welding wire 6 on the rear contact tip 4 does not exceed 5mm. The welding speed is adjusted according to the size of the welding groove 7, generally 24-90cm / min. For 4.8mm diameter welding wire 6, the welding current is 900-950A, the wire feed speed of welding wire 6 on the rear contact tip 4 is 90-160cm / min, the arc voltage is 34-38V, the wire extension length of welding wire 6 is 40-50mm, and the wire extension length error between welding wire 6 on the front contact tip 3 and welding wire 6 on the rear contact tip 4 does not exceed 5mm. The welding speed is adjusted according to the size of the welding groove 7, generally 29-95cm / min.

[0062] Adjust the tilt angle of the welding wire 6 on the front conductive nozzle 3 to an angle α with the vertical direction, where 5°≥α≥0°. Adjust the tilt angle of the welding wire 6 on the rear conductive nozzle 4 to an angle β with the vertical direction, where 22°≥β≥32°. Jog the front and rear welding wires 6 downwards and place them in a vertical plane. The ends of the welding wires 6 intersect and are basically in a horizontal plane. Adjust the distance from the intersection point of the welding wires 6 to the root of the bevel (i.e., the end where the V-shaped opening 701 connects to the blunt edge 702) to 7mm. Adjust the intersection point of the welding wires 6 to align with the root of the bevel.

[0063] During the welding process, the welder adjusts the height value according to the gap. The larger the gap, the greater the height value. As the height value increases, the current allocated to the first branch 9 also increases, up to half of the pre-current. However, the distance from the intersection of welding wire 6 to the root of the bevel does not exceed 11mm. During the welding process, as the height of the intersection increases, the arc voltage also needs to be increased.

[0064] Table 1 shows examples of process parameters for different thicknesses of base material 1. It should be noted that when welding the front side of the weld bevel, the wire extension of 6 refers to the distance between the front conductive tip 3 or the rear conductive tip 4 and the intersection of the two welding wires 3.

[0065] Table 1 Welding process parameters for the front side of the weld bevel

[0066]

[0067] Specifically, when the gap is 0-2mm or the width of the weld bevel 7 does not exceed 22mm, the welding direction is preferably as follows: Figure 2The welding is performed in the positive direction (i.e., the welding wire 6 on the front contact tip 3 in the figure is in front). In this case, the arc of the second branch 10 with a larger current is in front, and the penetration depth is larger without burning through. However, when the gap is 2-3mm or the width of the welding groove 7 exceeds 22mm, the welding is preferentially performed in the negative direction (i.e., the welding wire 6 on the rear contact tip 4 in the figure is behind). In this case, the arc of the first branch 9 with a smaller current is in front, the penetration depth is shallower, the weld is wider, and the gap is first fused to form a bridge, so that the subsequent second branch 10 will not burn through even if the current is larger.

[0068] The wire feeding speed of the welding wire 6 on the rear conductive tip 4 is adjusted according to the amount of filler metal required for the welding groove 7, and is generally no more than 0.6 times the wire feeding speed of the welding wire 6 on the front conductive tip 3. Increasing the wire feeding speed also increases the amount of deposited metal. The typical wire feeding speed range is 55cm / min-160cm / min. Examples of process parameters are shown in Table 1.

[0069] When the diameters of the welding wire 6 on the front conductive nozzle 3 and the welding wire 6 on the rear conductive nozzle 4 are the same, the welding current of the first branch 9 is one-third to one-half of the current flowing through the welding wire 6 on the front conductive nozzle 3, and the welding current of the second branch 10 is one-half to two-thirds of the current flowing through the welding wire 6 on the front conductive nozzle 3, depending on the height of the intersection of the welding wires 6. Therefore, compared with traditional submerged arc welding, the actual welding current used to melt the bevel of the workpiece base material 1 is reduced, which is beneficial to prevent burn-through when the gap is large. At the same time, two welding wires 6 are melted, and the deposition rate is increased. Taking a 750A AC square wave welding current as an example, with a welding wire 6 specification of 4mm, a dry extension of 40mm, and H1 of 7mm, the melting speed of welding wire 6 on the front contact tip 3 can reach 252cm / min, and the melting speed of welding wire 6 on the rear contact tip can reach 110cm / min, for a total melting speed of 362cm / min for the two welding wires 6. In contrast, the traditional single-power single-wire AC submerged arc welding technology has a welding wire melting speed of only 175.7cm / min under the same current, specification, and dry extension conditions, which is 2.06 times that of the traditional technology. Therefore, this method can greatly improve the welding efficiency of the welding groove front.

[0070] Welding on the non-grooved side of the weld: Output current in DC mode and use only the welding wire 6 on the front contact tip 3. Pre-set the process parameters on the submerged arc welding carriage. For a 4.0mm diameter welding wire 6, the welding current is 750-800A, the arc voltage is 34-36V, the wire extension is 32-42mm, and the welding speed is [not specified]. For a 4.8mm diameter welding wire 6, the welding current is 800-850A, the arc voltage is 34-36V, the wire extension is 40-50mm, the welding speed is 38-46cm / min, and the vertical tilt angle of the welding wire 6 is α, where 5°≥α≥0° (i.e., the angle between the welding wire 6 and the welding direction is 85°±5°). Examples of process parameters for base material 1 with different plate thicknesses are shown in Table 2. It should be noted that when welding the non-grooved side, the wire extension refers to the distance from the front contact tip 3 or the rear contact tip 4 to the bottom of the welding wire 3.

[0071] Table 2. Welding process parameters for the reverse side of the weld bevel.

[0072]

[0073] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings, and are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0074] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0075] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0076] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A Y-groove welding method, characterized in that, Includes the following steps: Step S10: A welding bevel is made on the base material to be welded. The welding bevel has a V-shaped opening on the front side and a blunt edge on the back side. Step S20: Place the base material on a horizontal operating surface and provide a welding device, which includes an AC / DC power supply and a twin-wire submerged arc welding carriage. Connect the negative output terminal of the AC / DC power supply to the rear conductive nozzle of the twin-wire submerged arc welding carriage and the base material, respectively. Connect the positive output terminal of the AC / DC power supply to the front conductive nozzle of the twin-wire submerged arc welding carriage. Install welding wires on the front and rear conductive nozzles, respectively, and bring the two welding wires into contact with one end of the base material. Adjust the AC / DC power supply to AC mode and use the two welding wires simultaneously to weld the front side of the welding bevel. Step S30: Switch the AC / DC power supply to DC mode and use the welding wire on the front conductive tip to weld the reverse side of the welding bevel.

2. The Y-groove welding method according to claim 1, characterized in that, The distance between the intersection of the welding wire on the front conductive tip and the welding wire on the rear conductive tip and the top of the blunt edge is H1. In step S20, before the two welding wires weld the front side of the welding groove, H1 is adjusted to 7mm. During the welding process of the front side of the welding groove, as the gap of the welding groove increases, H1 is gradually increased, and the maximum value of H1 does not exceed 11mm.

3. The Y-groove welding method according to claim 1, characterized in that, The two ends of the weld bevel along its length are the bevel ends. Welding the front side of the weld bevel includes the following steps: Step S21: Perform tack welding on the two bevel ends respectively to form a first welding area, and perform tack welding on the area between the two bevel ends to form a second welding area.

4. The Y-groove welding method according to claim 3, characterized in that, The length of the first welding area is L1, where L1 ≥ 100 mm; And / or, the length of the second welding area is L2, where L2 ≥ 50 mm.

5. The Y-groove welding method according to claim 3, characterized in that, The second welding area has two or more, all of which are spaced apart, and the interval between adjacent second welding areas is L3, where 300mm ≥ L3 ≥ 500mm.

6. The Y-groove welding method according to claim 3, characterized in that, The weld thickness of both the first welding zone and the second welding zone is less than 6 mm.

7. The Y-groove welding method according to claim 3, characterized in that, In step S20, two sets of positioning components are also provided, each set of positioning components being disposed on the side of the base material near the two bevel ends. Each set of positioning components includes a support plate and two positioning plates disposed on the side of the support plate near the V-shaped opening. The support plate is flush with the bottom of the V-shaped opening. The positioning welding of the bevel ends includes the following steps: Step S211: Install the support plate on the side of the operating surface near the bevel end and align the two positioning plates with the welding bevel, and weld and fix the support plate to the side of the base material located at the bevel end; Step S212: With the splice seam of the two parent materials as the center, the two positioning plates are inclinedly set on both sides of the splice seam so that a V-shaped groove is formed between the two positioning plates. The inclination direction of the two positioning plates is parallel to the inclination direction of the side wall corresponding to the V-shaped opening. The bottom of the positioning plate is welded and fixed to the support plate. Step S213: Perform tack welding inside the bevel end to obtain the first welding area, one end of which extends into the V-groove.

8. The Y-groove welding method according to claim 7, characterized in that, The length of the first welding area extending into the V-groove is L4, where L4 ≥ 50 mm.

9. The Y-groove welding method according to claim 1, characterized in that, Before welding the two welding wires to the front of the welding groove, the angle between the welding wire on the front conductive tip and the welding wire on the rear conductive tip is adjusted. The vertical tilt angle of the welding wire on the front conductive tip is controlled to be α, 5°≥α≥0°, and the vertical tilt angle of the welding wire on the rear conductive tip is controlled to be β, 22°≥β≥32°.

10. The Y-groove welding method according to any one of claims 1 to 9, characterized in that, Step S30 includes the following steps: Step S31, retract the welding wire on the rear conductive tip to separate the welding wire on the front conductive tip from the welding wire on the rear conductive tip, and disconnect the electrical connection between the welding wire on the rear conductive tip and the AC / DC power supply. Step S32: Flip the base material so that the reverse side of the welding bevel faces upward, and use the welding wire of the front conductive tip to weld to the blunt edge of the bevel.

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