A method for single power dual-wire welding of high-strength steel plate

Abstract

The application provides a method for single power source double-wire welding of medium-thick plate high-strength steel, which adopts a single power source double-wire welding gun, and the welding wire output end of the welding gun comprises a conducting nozzle, an insulating sleeve and a nozzle, a double-wire channel is formed in the conducting nozzle, a first protective gas channel is arranged between the conducting nozzle and the insulating sleeve, a second protective gas channel is arranged between the nozzle and the insulating sleeve, the front end of the insulating sleeve is arranged to protrude from the front end of the nozzle, and a wire gathering hole is arranged at the front end of the insulating sleeve opposite to the output port of the double-wire channel, so as to control the gap between the two welding wire ends; inert protective gas is input into the first protective gas channel, and active protective gas is input into the second protective gas channel during the welding process. The method for single power source double-wire welding of medium-thick plate high-strength steel can stably control the gap between the two welding wire ends, ensure the stability of arc shape and the stability of welding quality, and effectively solve the problem of poor welding process performance of traditional single power source double-wire welding when facing large welding seams of medium-thick plate high-strength steel.

Description

Technical Field

[0001] This invention relates to the field of welding, and more specifically, to a method for welding medium-thick high-strength steel plates using a single power source and dual welding wires. Background Technology

[0002] Hydraulic support structural components are mostly complex box-shaped structures (box-shaped structures are made of multiple plates welded together to form a "box"). The steel plates used are of high strength and thick, with complex and varied weld seams and large weld dimensions, requiring high welding heat input. Traditional welding methods for hydraulic support structural components often use single-wire welding with 1.2mm welding wire. Through research, the applicant developed an automatic welding method for hydraulic support structural components using a 1.6mm diameter welding wire in patent 201710134428.9, which improved welding efficiency by 40% compared to the 1.2mm wire method. Further research in patent 202110601546.2 revealed a method using a 1.4mm diameter welding wire, which further improved welding efficiency by more than 15% compared to the 1.6mm wire method. However, further improving the welding efficiency of hydraulic support structural components using the single-wire welding method has become more difficult.

[0003] Twin-wire welding is a high-speed and high-efficiency welding method developed in recent years. Currently, twin-wire welding is mainly divided into dual-power twin-wire welding and single-power twin-wire welding. Dual-power twin-wire welding uses two welding wires with independent power supplies and independent contact tips. Because the output end of the welding wire is flat and occupies a certain space, the space of hydraulic support structural components is limited, which makes dual-power twin-wire welding impossible to apply.

[0004] Single-power twin-wire welding involves two welding wires sharing the same power source and contact tip. The two wires form a single arc, and the consistency of the gap between the ends of the two wires directly determines the stability of the arc shape and the welding quality. Although the requirements for welding space are relatively low, on the one hand, due to the longer wire extension (generally 20-25mm), the ends of the two wires can easily separate into a large gap due to internal stress, which seriously affects the stability of the arc shape and welding quality. On the other hand, when using traditional mixed gas shielded welding (Ar+20%CO2) or CO2 gas shielded welding, the welding process is poor, especially at low currents, resulting in excessive welding spatter. If pure Ar shielding is used, although the welding spatter problem can be solved, the weld penetration will be too shallow. When dealing with hydraulic support welds, which are mainly composed of large welds in medium-thick plates and high-strength steel, this will seriously affect the mechanical properties and weld fusion.

[0005] In addition, the welding of hydraulic support structural components adopts multi-layer and multi-pass welding, with large weld size and large welding volume. Defects such as lack of fusion between weld passes are prone to occur, which makes it very difficult to explore welding heat input, welding method, welding parameters and weld pass layout.

[0006] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for welding medium-thick high-strength steel plates using a single-power-source dual-wire welding method. This method can stably control the gap between the ends of the two welding wires, ensure the stability of the arc shape and welding quality, and effectively solve the problem of poor welding processability when welding large welds of medium-thick high-strength steel plates using traditional single-power-source dual-wire welding.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a method for welding medium-thick high-strength steel plates with single-power dual-wire welding, wherein the welding wire output end of the single-power dual-wire welding gun includes a conductive tip, an insulating sleeve, and a nozzle, which are sequentially assembled from the inside to the outside. The conductive tip has a dual-wire channel, a first protective gas channel is provided between the insulating sleeve and the conductive tip, and a second protective gas channel is provided between the nozzle and the insulating sleeve. The front end of the insulating sleeve extends out of the front end of the nozzle, and a wire-gathering hole is provided at the front end of the insulating sleeve facing the output port of the dual-wire channel to control the gap between the ends of the two welding wires.

[0009] During the welding process, an inert shielding gas is introduced into the first shielding gas channel, and an active shielding gas is introduced into the second shielding gas channel. The method for welding medium-thick high-strength steel plates with a single power source and dual welding wires includes the following steps:

[0010] Step S1: Assemble the workpieces to be welded into the required weld seam;

[0011] Step S2: Perform the root pass weld on the weld seam;

[0012] Step S3: Perform a filler and cover weld on the weld seam.

[0013] Based on the above, φ1.4mm welding wire is used in the welding process.

[0014] Based on the above, the wire feeder used includes a first wire feeding wheel, a first wire pressing wheel, a second wire feeding wheel, and a second wire pressing wheel. The outer circumferential surfaces of the first wire feeding wheel and the first wire pressing wheel are provided with mutually cooperating first wire feeding grooves. The outer circumferential surfaces of the second wire feeding wheel and the second wire pressing wheel are provided with mutually cooperating second wire feeding grooves. The first wire feeding groove and the second wire feeding groove respectively feed one welding wire to the single-power dual-wire welding gun. The first wire pressing wheel can be positioned close to or far from the first wire feeding wheel so that the first wire feeding groove can press or release one of the welding wires, realizing the switching between single-wire welding mode and dual-wire welding mode.

[0015] In step S1, the workpieces to be welded are assembled into a fillet weld;

[0016] In step S2, the single-power dual-wire welding gun is switched to single-wire welding mode for root pass welding.

[0017] In step S3, the single-power dual-wire welding gun is switched to dual-wire welding mode for filler and cover welding.

[0018] Based on the above, the welding parameters in step S2 are set as follows: welding current 400-450A, welding voltage 34-37V, wire feed speed 11-12m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, the protective gas flow rate in the first protective gas channel is 10-15L / min, and the protective gas flow rate in the second protective gas channel is 15-25L / min.

[0019] In step S3, when the fillet weld leg size is 12-14mm, only one filler / cap weld bead is set. The welding parameters are set as follows: welding current 600-700A, welding voltage 37-39V, wire feed speed of each welding wire 9-10m / min, welding speed 80-100cm / min, oscillation width 8-10mm, oscillation frequency 3.5-4.5Hz, dwell time on both sides 0.3s, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min.

[0020] When the fillet weld leg size is 16-18mm, two filler and capping passes are arranged side by side. The welding parameters for the first filler and capping pass are: welding current 650-700A, voltage 37-39V, wire feed speed of each welding wire: 9.5-10m / min, welding speed: 90-110cm / min, oscillation width 6-8mm, oscillation frequency 4.5-5.0Hz, dwell time on both sides 0.10s, and the shielding gas flow rate in the first shielding gas channel is 10-15L / min. The shielding gas flow rate in the shielding gas channel is 15-25 L / min. The welding parameters for the other filler and cover pass are: welding current 600-650 A, welding voltage 35-36 V, wire feed speed of each welding wire 9-9.5 m / min, welding speed 100-120 cm / min, oscillation width 4-6 mm, oscillation frequency 5.0-5.5 Hz. The shielding gas flow rate in the first shielding gas channel is 10-15 L / min, and the shielding gas flow rate in the second shielding gas channel is 15-25 L / min.

[0021] Based on the above, in step S1, the workpieces to be welded are assembled into a bevel weld.

[0022] In step S2, the single-power dual-wire welding gun is set to dual-wire welding mode for root pass welding.

[0023] In step S3, the single-power dual-wire welding gun is set to dual-wire welding mode for filler and cover welding.

[0024] Based on the above, in step S3, when the groove weld depth is 12-14mm and the angle is 35-45°, only the first filler and cover weld bead is set. When the groove weld depth is 16-18mm and the angle is 35-45°, a second filler and cover weld bead is added above the first filler and cover weld bead. When the groove weld depth is 20-23mm and the angle is 35-45°, a third and a fourth filler and cover weld bead are added above the second filler and cover weld bead. The third and fourth filler and cover weld bead are set side by side.

[0025] Based on the above, the welding parameters in step S2 are set as follows: welding current 420-450A, welding voltage 33-36V, wire feeding speed of each welding wire 6-6.5m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0026] In step S3, the welding parameters for the first filler / cover weld bead are: welding current 630-650A, welding voltage 37-38V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 4-6mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0027] The welding parameters for the second filler / cover weld are as follows: welding current 650-700A, welding voltage 37.5-38.5V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 5-7mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0028] The welding parameters for the third filler / cover weld are as follows: welding current 620-660A, welding voltage 35-37V, wire feed speed of each welding wire 9-9.5m / min, welding speed 100-110cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0029] The welding parameters for the fourth filler and cover pass are as follows: welding current 600-620A, welding voltage 36-37V, wire feed speed of each welding wire 9m / min, welding speed 100-120cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min.

[0030] Based on the above, the workpiece to be welded is a structural component of a hydraulic support.

[0031] Based on the above, the first protective gas channel is supplied with pure Ar protective gas, and the second protective gas channel is supplied with a mixed protective gas of Ar + 20% CO2.

[0032] Based on the above, pulse welding mode was used in the welding process.

[0033] This invention has outstanding substantive features and significant progress compared to the prior art. Specifically, this invention has the following advantages:

[0034] (1) By opening the wire-gathering hole at the front end of the insulating sleeve, the gap between the ends of the two welding wires is controlled to ensure that the ends of the two welding wires do not diverge after they extend from the conductive nozzle, thus ensuring the stability of the arc and the stability of the welding quality. By introducing inert protective gas into the first protective gas channel, the inert protective gas acts directly on the arc before the two welding wires are output from the welding gun, which can effectively reduce the resistance of the molten droplet transition of the welding arc and thus reduce welding spatter. Introducing active protective gas into the second protective gas channel acts on the periphery of the arc and the workpiece, which can increase the penetration depth of the weld and ensure the fusion of the weld. This solves the problem of poor welding processability when using a single power source and two welding wires to weld large welds of medium and thick high-strength steel plates, thus ensuring the welding quality.

[0035] (2) Since this patent solves the problem of poor welding processability when using single power supply double welding wire to weld large welds of medium and thick plate high strength steel, it enables single power supply double welding wire to be used for welding large welds of medium and thick plate high strength steel. The single power supply double welding wire welding has relatively low requirements for operating space and can be applied to the operation of welds of hydraulic support structural parts (box structure), thereby greatly improving the welding efficiency of hydraulic support structural parts.

[0036] (3) The welds of the hydraulic support structure are all multi-layer and multi-pass welds. The welding size is large and the welding volume is large. This patent effectively solves the problem of non-fusion defects between welds by planning different weld passes for different welds and setting different welding parameters for different weld passes. The welding heat input, welding method and welding parameters of each weld pass are well adapted to the welding requirements of the hydraulic support, and realize the continuous welding of complex welds of the box structure by single power supply and double welding wire.

[0037] (4) This patent enables the switching function of single and double wires by setting the first pressure roller in the wire feeder to be close to or far away from the first wire feed roller. When the fillet weld is used for the root pass welding, single wire welding is used. The single wire has strong arc penetration, thereby obtaining a greater penetration depth, increasing the stress area of ​​the fillet weld root pass welding, and ensuring the quality of the weld. When the fillet weld is used for the fillet weld fillet ... Attached Figure Description

[0038] Figure 1 This is a cross-sectional schematic diagram of the single-power dual-wire welding gun used in this invention.

[0039] Figure 2 yes Figure 1 A magnified view of area A in the middle.

[0040] Figure 3 This is a schematic diagram of the insulating sleeve of the single-power dual-wire welding gun used in this invention.

[0041] Figure 4 This is a schematic diagram showing the usage status of the wire gathering hole of the single-power dual-wire welding gun used in this invention.

[0042] Figure 5 This is a weld bead layout diagram for fillet welds with a weld leg size of 12-14mm in this invention.

[0043] Figure 6 This is a weld bead layout diagram for fillet welds with a weld leg size of 16-18mm in this invention.

[0044] Figure 7 This is a weld bead layout diagram of a groove weld with a depth of 12-14mm in this invention.

[0045] Figure 8This is a weld bead layout diagram of a groove weld with a depth of 16-18mm in this invention.

[0046] Figure 9 This is a weld bead layout diagram of a groove weld with a depth of 20-23mm in this invention.

[0047] Figure 10 This is a schematic diagram of the wire feeder used in this invention.

[0048] Figure 11 This is a schematic diagram of the wire feeding process of the first wire feeding wheel and the first wire pressing wheel in this invention.

[0049] Figure 12 This is a schematic diagram of the wire feeding process of the second wire feeding wheel and the second wire pressing wheel in this invention.

[0050] In the diagram: 1. Conductive tip; 2. Connecting rod; 3. Insulating sleeve; 4. Nozzle; 5. Wire gathering hole; 6. First protective gas channel; 7. Second protective gas channel; 8. Air inlet channel; 9. Vent hole; 10. Welding wire; 11. First wire feeding wheel; 12. First wire pressing wheel; 13. Second wire feeding wheel; 14. Second wire pressing wheel. Detailed Implementation

[0051] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0052] A method for welding medium-thick high-strength steel plates using a single power source and dual welding wires, such as... Figure 1-4 As shown, the welding gun used in this welding method employs a single-power dual-wire welding torch. The wire output end includes a conductive nozzle 1, a connecting rod 2, an insulating sleeve 3, and a nozzle 4. The conductive nozzle 1 has a dual-wire channel. The conductive nozzle 1, the insulating sleeve 3, and the nozzle 4 are sequentially fitted together from the inside out. The insulating sleeve 3 can be made of high-toughness metal ceramic with a high-temperature resistant insulating layer on its surface. The front end of the insulating sleeve 3 extends 3-5mm beyond the front end of the nozzle 4. A wire-gathering hole 5 is provided at the front end of the insulating sleeve 3, directly opposite the output port of the dual-wire channel. The inner diameter of the wire-gathering hole 5 can exceed the sum of the diameters of the two welding wires 10 by 0.3-0.5mm to control the gap between the ends of the two welding wires 10, ensuring that the ends of the two welding wires 10 do not diverge after extending from the conductive nozzle 1, thus ensuring the stability of the arc shape and the stability of the welding quality.

[0053] The insulating sleeve 3 and the conductive nozzle 1 are provided with a first protective gas channel 6, and the nozzle 4 and the insulating sleeve 3 are provided with a second protective gas channel 7. The front end of the connecting rod 2 is connected to the rear end of the conductive nozzle 1, the rear end of the insulating sleeve 3 is sleeved on the outer circumferential surface of the connecting rod 2, the connecting rod 2 is provided with an air inlet channel 8, and the side wall of the connecting rod 2 is provided with a plurality of vent holes 9. The air inlet channel 8 is connected to the first protective gas channel 6 through the plurality of vent holes 9.

[0054] During the welding process, an inert shielding gas, specifically pure Ar shielding gas, is introduced into the first shielding gas channel 6. This allows the pure Ar shielding gas to directly act on the arc before the two welding wires exit the welding torch, effectively reducing the droplet transfer resistance of the welding arc and thus reducing welding spatter. An active shielding gas, specifically a mixture of Ar and 20% CO2, is introduced into the second shielding gas channel 7. This gas acts on the periphery of the arc and the workpiece, increasing the weld penetration and ensuring the weld fusion. This solves the problem of poor welding processability when welding large welds of medium-thick high-strength steel plates using a single-power source and dual welding wires, thus ensuring welding quality.

[0055] In this embodiment, a φ1.4mm welding wire is used in the welding process. In other embodiments, welding wires such as φ1.2mm and φ1.6mm can also be used for single-power dual-wire welding.

[0056] like Figure 10-12 The wire feeder used in this welding method includes a first wire feeding wheel 11, a first wire pressing wheel 12, a second wire feeding wheel 13, and a second wire pressing wheel 14. The outer circumferential surfaces of the first wire feeding wheel 11 and the first wire pressing wheel 12 are provided with mutually cooperating first wire feeding grooves, and the outer circumferential surfaces of the second wire feeding wheel 13 and the second wire pressing wheel 14 are provided with mutually cooperating second wire feeding grooves. The first wire feeding groove and the second wire feeding groove respectively feed one welding wire to the single-power dual-wire welding gun. The first wire pressing wheel 12 can be positioned close to or far from the first wire feeding wheel 11 so that the first wire feeding groove can press or release one of the welding wires, thereby realizing the switching between single-wire welding mode and dual-wire welding mode.

[0057] For fillet welds, this method for welding medium-thick high-strength steel plates using a single power source and dual welding wires includes the following steps:

[0058] Step S1: Assemble the workpieces to be welded into a fillet weld;

[0059] Step S2: Switch the single-power dual-wire welding gun to single-wire welding mode for root pass welding. The welding parameters are set as follows: welding current 400-450A, welding voltage 34-37V, wire feed speed 11-12m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, shielding gas flow rate in the first shielding gas channel is 10-15L / min, and shielding gas flow rate in the second shielding gas channel is 15-25L / min.

[0060] In this step, due to the strong penetrating power of the single-wire arc, a greater penetration depth can be obtained, increasing the stress area of ​​the fillet weld root pass and ensuring weld quality.

[0061] Step S3: Switch the single-power dual-wire welding gun to dual-wire welding mode for filler and cover welding. When the fillet weld leg size is 12-14mm, such as... Figure 5 As shown, only one filler / cover weld bead is set, and the welding parameters are set as follows: welding current 600-700A, welding voltage 37-39V, wire feed speed of each welding wire 9-10m / min, welding speed 80-100cm / min, oscillation width 8-10mm, oscillation frequency 3.5-4.5Hz, dwell time on both sides 0.3s, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0062] When the fillet weld leg size is 16-18mm, such as Figure 6 As shown, two filler and cover passes are arranged side by side. The welding parameters for the first filler and cover pass are: welding current 650-700A, voltage 37-39V, wire feed speed per wire: 9.5-10m / min, welding speed: 90-110cm / min, oscillation width 6-8mm, oscillation frequency 4.5-5.0Hz, dwell time on both sides 0.10s, and the shielding gas flow rate in the first shielding gas channel is 10-15L / min. The gas flow rate is 15-25 L / min. The welding parameters for the other filler and cover pass are: welding current 600-650 A, welding voltage 35-36 V, wire feed speed of each welding wire 9-9.5 m / min, welding speed 100-120 cm / min, oscillation width 4-6 mm, oscillation frequency 5.0-5.5 Hz, the shielding gas flow rate in the first shielding gas channel is 10-15 L / min, and the shielding gas flow rate in the second shielding gas channel is 15-25 L / min.

[0063] This step uses twin-wire welding, which can carry a larger current, reduce the number of welding passes, and greatly improve welding efficiency.

[0064] For bevel welds, this method for welding medium-thick high-strength steel plates using a single power source and dual welding wires includes the following steps:

[0065] Step S1: Assemble the workpieces to be welded into a bevel weld.

[0066] Step S2: Set the single-power dual-wire welding gun to dual-wire welding mode for root pass welding. The welding parameters are set as follows: welding current 420-450A, welding voltage 33-36V, wire feed speed of each welding wire 6-6.5m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, shielding gas flow rate in the first shielding gas channel is 10-15L / min, and shielding gas flow rate in the second shielding gas channel is 15-25L / min.

[0067] The arc of single-power twin-wire welding is wider, and the formation of single-pass weld is better. When twin-wire root pass welding is used in this step, the occurrence of defects such as root burn-through of the groove weld can be reduced.

[0068] Step S3: Set the single-power dual-wire welding gun to dual-wire welding mode for filler and cover welding. When the bevel weld depth is 12-14mm and the angle is 35-45°, as follows... Figure 7 As shown, only the first filler / cap weld bead is set. When the groove weld depth is 16-18mm and the angle is 35-45°, as shown... Figure 8 As shown, a second filler / cap weld bead is added above the first filler / cap weld bead. When the groove weld depth is 20-23mm and the angle is 35-45°, as follows... Figure 9 As shown, a third and a fourth filler weld are added above the second filler weld, and the third and fourth filler welds are arranged side by side.

[0069] The welding parameters for the first filler / cover weld are as follows: welding current 630-650A, welding voltage 37-38V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 4-6mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0070] The welding parameters for the second filler / cover weld are as follows: welding current 650-700A, welding voltage 37.5-38.5V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 5-7mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0071] The welding parameters for the third filler / cover weld are as follows: welding current 620-660A, welding voltage 35-37V, wire feed speed of each welding wire 9-9.5m / min, welding speed 100-110cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min;

[0072] The welding parameters for the fourth filler and cover pass are as follows: welding current 600-620A, welding voltage 36-37V, wire feed speed of each welding wire 9m / min, welding speed 100-120cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min.

[0073] Throughout the welding process, pulse welding mode is used. Since single-power dual-wire welding has relatively low requirements for operating space, it is suitable for welding occasions with limited space, such as box structures. The workpiece to be welded can be a structural component of a hydraulic support.

[0074]

[0075] The table above compares the welding efficiency of hydraulic support structural components using traditional φ1.6mm single-wire welding and φ1.4mm double-wire welding as described in this patent. As can be seen from the table, the welding efficiency of this patented welding method can be increased by 10%-33% during the root pass welding and by more than 70% during the fill and cover pass welding.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for welding medium-thick high-strength steel plates using a single power source and dual welding wires, characterized in that: The welding wire output end of the single-power dual-wire welding gun it uses includes a conductive tip, an insulating sleeve, and a nozzle, which are sequentially assembled from the inside to the outside. The conductive tip has a dual welding wire channel. A first protective gas channel is provided between the insulating sleeve and the conductive tip. A second protective gas channel is provided between the nozzle and the insulating sleeve. The front end of the insulating sleeve extends out of the front end of the nozzle. The front end of the insulating sleeve is provided with a wire gathering hole facing the output port of the dual welding wire channel to control the gap between the ends of the two welding wires. During the welding process, an inert shielding gas is introduced into the first shielding gas channel, and an active shielding gas is introduced into the second shielding gas channel. The first shielding gas channel uses pure Ar shielding gas, and the second shielding gas channel uses a mixture of Ar and 20% CO2 shielding gas. The method for welding medium-thick high-strength steel plates with a single power source and dual welding wires includes the following steps: Step S1: Assemble the workpieces to be welded into the required weld seam; Step S2: Perform the root pass weld on the weld seam; Step S3: Perform a filler and cover weld on the weld; use φ1.4mm welding wire during the welding process; The wire feeder it employs includes a first wire feeding wheel, a first wire pressing wheel, a second wire feeding wheel, and a second wire pressing wheel. The outer circumferential surfaces of the first wire feeding wheel and the first wire pressing wheel are provided with mutually cooperating first wire feeding grooves. The outer circumferential surfaces of the second wire feeding wheel and the second wire pressing wheel are provided with mutually cooperating second wire feeding grooves. The first wire feeding groove and the second wire feeding groove respectively feed one welding wire to the single-power dual-wire welding gun. The first wire pressing wheel can be positioned close to or far from the first wire feeding wheel so that the first wire feeding groove can press or release one of the welding wires, realizing the switching between single-wire welding mode and dual-wire welding mode. In step S1, the workpieces to be welded are assembled into a fillet weld; In step S2, the single-power dual-wire welding gun is switched to single-wire welding mode for root pass welding. In step S3, the single-power dual-wire welding gun is switched to dual-wire welding mode for filler and cover welding. In step S2, the welding parameters are set as follows: welding current 400-450A, welding voltage 34-37V, wire feed speed 11-12m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, the protective gas flow rate in the first protective gas channel is 10-15L / min, and the protective gas flow rate in the second protective gas channel is 15-25L / min. In step S3, when the fillet weld leg size is 12-14mm, only one filler / cap weld bead is set. The welding parameters are set as follows: welding current 600-700A, welding voltage 37-39V, wire feed speed of each welding wire 9-10m / min, welding speed 80-100cm / min, oscillation width 8-10mm, oscillation frequency 3.5-4.5Hz, dwell time on both sides 0.3s, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min. When the fillet weld leg size is 16-18mm, two filler and capping passes are arranged side by side. The welding parameters for the first filler and capping pass are: welding current 650-700A, voltage 37-39V, wire feed speed of each welding wire: 9.5-10m / min, welding speed: 90-110cm / min, oscillation width 6-8mm, oscillation frequency 4.5-5.0Hz, dwell time on both sides 0.10s, and the shielding gas flow rate in the first shielding gas channel is 10-15L / min. The shielding gas flow rate in the shielding gas channel is 15-25 L / min. The welding parameters for the other filler and cover pass are: welding current 600-650 A, welding voltage 35-36 V, wire feed speed of each welding wire 9-9.5 m / min, welding speed 100-120 cm / min, oscillation width 4-6 mm, oscillation frequency 5.0-5.5 Hz. The shielding gas flow rate in the first shielding gas channel is 10-15 L / min, and the shielding gas flow rate in the second shielding gas channel is 15-25 L / min.

2. The method for welding medium-thick high-strength steel plates using a single power source and dual welding wires according to claim 1, characterized in that: The workpiece to be welded is a structural component of a hydraulic support.

3. The method for welding medium-thick high-strength steel plates using a single power source and dual welding wires according to claim 2, characterized in that: The welding process uses pulse welding mode.

4. A method for welding medium-thick high-strength steel plates using a single power source and dual welding wires, characterized in that: The welding wire output end of the single-power dual-wire welding gun it uses includes a conductive tip, an insulating sleeve, and a nozzle, which are sequentially assembled from the inside to the outside. The conductive tip has a dual welding wire channel. A first protective gas channel is provided between the insulating sleeve and the conductive tip. A second protective gas channel is provided between the nozzle and the insulating sleeve. The front end of the insulating sleeve extends out of the front end of the nozzle. The front end of the insulating sleeve is provided with a wire gathering hole facing the output port of the dual welding wire channel to control the gap between the ends of the two welding wires. During the welding process, an inert shielding gas is introduced into the first shielding gas channel, and an active shielding gas is introduced into the second shielding gas channel. The first shielding gas channel uses pure Ar shielding gas, and the second shielding gas channel uses a mixture of Ar and 20% CO2 shielding gas. The method for welding medium-thick high-strength steel plates with a single power source and dual welding wires includes the following steps: φ1.4mm welding wire was used during the welding process; In step S1, the workpieces to be welded are assembled into a bevel weld. In step S2, the single-power dual-wire welding gun is set to dual-wire welding mode for root pass welding. In step S3, the single-power dual-wire welding gun is set to dual-wire welding mode for filler and cover welds. In step S3, when the groove weld depth is 12-14mm and the angle is 35-45°, only the first filler and cover weld pass is set. When the groove weld depth is 16-18mm and the angle is 35-45°, a second filler and cover weld pass is added above the first filler and cover weld pass. When the groove weld depth is 20-23mm and the angle is 35-45°, a third and a fourth filler and cover weld pass are added above the second filler and cover weld pass. The third and fourth filler and cover weld passes are set side by side. In step S2, the welding parameters are set as follows: welding current 420-450A, welding voltage 33-36V, wire feed speed of each welding wire 6-6.5m / min, welding speed 45-55cm / min, oscillation width 2-4mm, oscillation frequency 2.08Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min. In step S3, the welding parameters for the first filler / cover weld bead are: welding current 630-650A, welding voltage 37-38V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 4-6mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min; The welding parameters for the second filler / cover weld are as follows: welding current 650-700A, welding voltage 37.5-38.5V, wire feed speed of each welding wire 10m / min, welding speed 90-100cm / min, oscillation width 5-7mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min; The welding parameters for the third filler / cover weld are as follows: welding current 620-660A, welding voltage 35-37V, wire feed speed of each welding wire 9-9.5m / min, welding speed 100-110cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min; The welding parameters for the fourth filler and cover pass are as follows: welding current 600-620A, welding voltage 36-37V, wire feed speed of each welding wire 9m / min, welding speed 100-120cm / min, oscillation width 3-5mm, oscillation frequency 3.0-3.5Hz, shielding gas flow rate in the first shielding gas channel 10-15L / min, and shielding gas flow rate in the second shielding gas channel 15-25L / min.

5. The method for welding medium-thick high-strength steel plates using a single power source and dual welding wires according to claim 4, characterized in that: The workpiece to be welded is a structural component of a hydraulic support.

6. The method for welding medium-thick high-strength steel plates using a single power source and dual welding wires according to claim 5, characterized in that: The welding process uses pulse welding mode.

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