A welding method

Abstract

This invention belongs to the field of welding technology and relates to a surfacing welding method. The surfacing welding method provided by this invention includes the following steps: fixing the workpiece to a dual-wire dual-arc submerged arc welding device, and performing surfacing welding using dual-wire dual-arc submerged arc welding; the dual-wire dual-arc submerged arc welding includes front wire welding and rear wire welding. The conditions for front wire welding include: the front wire current is an alternating current of 400-420A, the front wire voltage is 46-48V, the front wire welding speed is 45-47cm / min, and the angle between the front wire and the welding direction is 90°; the conditions for rear wire welding include: the rear wire current is a reverse DC current of 350-450A, the rear wire voltage is 46-48V, the rear wire welding speed is 45-47cm / min, and the angle between the rear wire and the welding direction is 110-115°; the distance between the front and rear wires along the parallel weld direction is 60-75mm, and the distance along the perpendicular weld direction is 10-15mm.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and specifically relates to a welding overlay method. Background Technology

[0002] Hardfacing, as an economical and rapid process for material surface modification, is widely used in the manufacturing and maintenance of various reactors, heat exchangers, and pressure vessels. It is used to improve the corrosion resistance and heat resistance of working surfaces, optimize material usage, reduce costs, and enhance overall performance and service life. Traditional hardfacing mostly employs manual welding methods, but manual welding suffers from drawbacks such as low welding efficiency, high workload, and inconsistent weld quality.

[0003] With industrial development, strip electrode welding has emerged. Strip electrode welding has advantages such as high production efficiency, lower dilution rate and good weld formation. However, strip electrode welding requires special machines for welding, and the high price of special machines for strip electrode welding greatly increases the production cost of welding. Summary of the Invention

[0004] In view of this, the present invention provides a welding method that can complete welding with high efficiency and reduce the welding cost of welding.

[0005] To solve the above-mentioned technical problems, the present invention provides a welding overlay method, comprising the following steps:

[0006] The workpiece is fixed to a double-wire double-arc submerged arc welding equipment and surfacing is performed using double-wire double-arc submerged arc welding.

[0007] The dual-wire dual-arc submerged arc welding includes front wire welding and rear wire welding. The conditions for front wire welding include: front wire current is alternating current, the alternating current is 400-420A, front wire voltage is 46-48V, front wire welding speed is 45-47cm / min, and the angle between the front wire and the welding direction is 90°.

[0008] The conditions for back wire welding include: the back wire current is a DC reverse current, the DC reverse current is 350-450A, the back wire voltage is 46-48V, the back wire welding speed is 45-47cm / min, and the angle between the back wire and the welding direction is 110-115°.

[0009] The front and rear wires are 60-75 mm apart along the direction parallel to the weld bead; the front and rear wires are 10-15 mm apart along the direction perpendicular to the weld bead.

[0010] Preferably, the conditions for front wire welding include: front wire current is alternating current, the alternating current is 410-420A, front wire voltage is 47V, front wire welding speed is 46cm / min, and the angle between the front wire and the welding direction is 90°.

[0011] The conditions for back wire welding include: the back wire current is a DC reverse current, the DC reverse current is 375~385A, the back wire voltage is 47V, the back wire welding speed is 46cm / min, and the angle between the back wire and the welding direction is 110~115°.

[0012] Preferably, the number of welding passes for the front wire is one more than the number of welding passes for the rear wire, and the number of welding passes for the front wire is 2 to 3.

[0013] Preferably, the diameters of the front and back filaments are independently 4 to 6 mm.

[0014] Preferably, before performing the surfacing using dual-wire dual-arc submerged arc welding, the process further includes: grinding the workpiece; cleaning and drying the front and rear wires respectively;

[0015] The drying temperature is 300-400℃, and the drying time is 1.8-2.2h.

[0016] Preferably, the weld overlay includes a stacked transition layer and a composite layer; the composite layer includes a first composite layer and a second composite layer;

[0017] When performing double-wire double-arc submerged arc welding, the front wire is used to weld the transition layer, and the rear wire is used to weld the first composite layer; the front wire and the rear wire are used to weld the second composite layer.

[0018] After obtaining the transition layer and the first composite layer, hydrogen removal treatment is performed.

[0019] Preferably, the temperature of the hydrogen removal treatment is 300–350°C, and the time of the hydrogen removal treatment is 28–32 min.

[0020] Preferably, the material of the weldment is alloy steel; the alloy steel is Q345R.

[0021] Preferably, the transition layer is welded using a front wire, and the front wire used for welding the transition layer is H10Cr24Ni13 welding wire;

[0022] The composite layer is welded simultaneously using both the front and rear wires. When welding the composite layer, the front wire is H0Cr21Ni10 welding wire and the rear wire is H0Cr21Ni10 welding wire.

[0023] Preferably, the flux used for the dual-wire dual-arc submerged arc welding is SJ601 flux.

[0024] This invention provides a surfacing welding method, comprising the following steps: fixing the workpiece to a dual-wire dual-arc submerged arc welding device, and performing surfacing welding using dual-wire dual-arc submerged arc welding; the dual-wire dual-arc submerged arc welding includes front wire welding and rear wire welding, wherein the conditions for front wire welding include: front wire current is alternating current, the alternating current is 400-420A, front wire voltage is 46-48V, front wire welding speed is 45-47cm / min, and the angle between the front wire and the welding direction is 90°; the conditions for rear wire welding include: rear wire current is reverse DC current, the reverse DC current is 350-450A, rear wire voltage is 46-48V, rear wire welding speed is 45-47cm / min, and the angle between the rear wire and the welding direction is 110-115°; the distance between the front wire and the rear wire along the parallel weld direction is 60-75mm; the distance between the front wire and the rear wire along the perpendicular weld direction is 10-15mm. In this invention, during dual-wire, dual-arc submerged arc welding, the front wire uses AC and the rear wire uses DC, with a low current and high voltage. This increases the weld width and reduces the weld depth, thereby reducing the fusion ratio. By limiting the welding current, voltage, welding speed, wire tilt angle, and the spacing between the front and rear wires, high-quality surfacing welds can be obtained efficiently under specific conditions. The results from the embodiments show that the welding method provided by this invention improves welding efficiency by 10 times compared to traditional manual electrode surfacing welding, while maintaining roughly the same material cost. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the arrangement of two wires in double-wire double-arc submerged arc welding, where Figure a is a view perpendicular to the welding direction and Figure b is a view along the welding direction.

[0026] Figure 2 Macroscopic metallographic images of the weld seam after dyeing treatment were obtained in Example 1;

[0027] Figure 3 The images shown are metallographic micrographs of the weld cross-section obtained in Example 1, where (a) is a metallographic micrograph of the alloy steel side and (b) is a metallographic micrograph of the interface of the fusion zone.

[0028] Figure 4 The images shown are metallographic microstructures of the weld cross-section obtained in Comparative Example 4, where (c) is the metallographic microstructure of the alloy steel side and (d) is the metallographic microstructure of the fusion zone interface. Detailed Implementation

[0029] This invention provides a welding overlay method, comprising the following steps:

[0030] The workpiece is fixed to a dual-wire, dual-arc submerged arc welding (SAW) machine, and SAW is performed using SAW. Preferably, before SAW, the invention further includes: grinding the workpiece; cleaning oil stains from the front and rear welding wires respectively; and drying the flux according to usage requirements. Grinding removes impurities from the surface of the workpiece; these impurities include rust and / or scale. In this invention, the grinding area is preferably within 20mm on both sides of the weld. This invention does not have special requirements for the grinding method, as long as it removes surface impurities and dirt. Grinding in this invention can reduce internal crack sources in the workpiece.

[0031] This invention does not have special requirements for the cleaning methods of the front and rear welding wires; conventional methods in the art can be used. In this invention, the drying temperature is preferably 300–400°C, more preferably 340–360°C; the drying time is preferably 1.8–2.2 hours, more preferably 2 hours.

[0032] In this invention, the material of the weldment is preferably low alloy steel; the low alloy steel is preferably Q345R.

[0033] In this invention, the dual-wire dual-arc submerged arc welding includes front wire welding and rear wire welding. The conditions for front wire welding include: the front wire current is an alternating current, preferably 405-415A; the front wire voltage is 46-48V, preferably 47V; the front wire welding speed is 45-47cm / min, preferably 46cm / min; and the angle between the front wire and the welding direction is 90°. In this invention, the diameter of the front wire is preferably 4-6mm, more preferably 5mm. This invention does not specifically limit the type of front wire; it can be conventionally selected according to the material of the workpiece.

[0034] In this invention, the number of welding passes of the front wire is preferably one more than the number of welding passes of the rear wire, and the number of welding passes of the front wire is preferably 2 to 3.

[0035] In this invention, the weld overlay preferably comprises a stacked transition layer and a composite layer; the composite layer comprises a first composite layer and a second composite layer. Preferably, the transition layer is welded using a front wire, the first composite layer is welded using a back wire, and the second composite layer is welded using both front and back wires. In this invention, the thermal energy during front wire welding of the transition layer is preferably less than or equal to 26 kJ / cm, more preferably 25.07–25.74 kJ / cm.

[0036] In this invention, when welding the first composite layer using a back wire, the back wire current is a DC reverse current, which is 350-450A, preferably 370-390A, and more preferably 375-385A; the back wire voltage is 39-48V, preferably 42-48V, and more preferably 46-47V; the back wire welding speed is 45-47cm / min, preferably 46cm / min; the angle between the back wire and the welding direction is 110-115°, preferably 112-114°; the distance between the front wire and the back wire along the parallel weld direction is 60-75mm, preferably 65-70mm. In this invention, the diameter of the back wire is preferably 4-6mm, and more preferably 5mm. This invention does not specifically limit the type of back wire; it can be conventionally selected based on the material of the workpiece.

[0037] In this invention, the number of passes for the back wire welding is preferably 1 to 2, and more preferably 1 to better suit the actual needs of surfacing welding production. This invention preferably utilizes a back wire welding composite layer; when utilizing the back wire welding composite layer, the thermal energy is preferably less than or equal to 24 kJ / cm, more preferably 23.19 to 23.90 kJ / cm.

[0038] In this invention, after obtaining the transition layer and the first composite layer, a hydrogen removal treatment is preferably performed. Before the hydrogen removal treatment, the surfaces of the transition layer and the first composite layer are preferably wiped with acetone to remove surface oil contaminants. In this invention, the temperature of the hydrogen removal treatment is preferably 300–350°C, more preferably 310–340°C; the time of the hydrogen removal treatment is preferably 28–32 minutes, more preferably 30 minutes. The hydrogen removal treatment of this invention can improve the toughness of the transition layer, thereby improving the mechanical properties of the weld.

[0039] When welding the second composite layer using the front and rear wires, the welding conditions for the front wire are preferably the same as those for welding the transition layer, and will not be repeated here. Similarly, when welding the second composite layer using the front and rear wires, the welding conditions for the rear wire are preferably the same as those for welding the first composite layer, and will not be repeated here. When welding the second composite layer, the number of welding passes for the front and rear wires is preferably the same.

[0040] In this invention, the first pass of the double-wire double-arc submerged arc welding is preferably performed using the front wire, and the weld beads formed by the two adjacent welding wires should overlap by 1 / 3 to 1 / 2 to ensure the thickness of the weld overlay at all points; the first pass is a transition layer.

[0041] Figure 1The diagram illustrates the arrangement of twin wires in a twin-wire, twin-arc submerged arc welding process. Figure a is a view perpendicular to the welding direction, and Figure b is a view along the welding direction. The angle between the front wire and the welding direction is 90°, and the inclination angle of the rear wire is 110-115°. The distance between the front and rear wires along the direction parallel to the weld bead is 60-75 mm, preferably 68-73 mm. The distance between the front and rear wires along the direction perpendicular to the weld bead is 10-15 mm, preferably 12-14 mm.

[0042] In this invention, when the material of the weldment is Q345R, the preferred front wire used when welding the transition layer is H10Cr24Ni13 welding wire, the preferred front wire used when welding the composite layer is H0Cr21Ni10 welding wire, the preferred rear wire used when welding the composite layer is H0Cr21Ni10 welding wire, and the preferred flux used for welding is SJ601 flux.

[0043] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] The welding object is a Q345R material with a size of 600mm×400mm×26mm. The transition layer is welded with ER309 (H10Cr24Ni13) welding wire with a diameter of 4mm. The composite layer is welded with ER308 (H0Cr21Ni10) welding wire with a diameter of 4mm as the front wire and ER308 (H0Cr21Ni10) welding wire with a diameter of 4mm as the rear wire. The flux is SJ601 (F308-H0Cr21Ni10) welding flux.

[0046] Grind the area 20mm on both sides of the weldment to remove rust, scale and oil; clean the front and back wires with acetone to remove oil, and dry the flux at 350℃ for 2 hours according to the usage requirements;

[0047] The front wire current is AC, and the rear wire current is DC reverse polarity. The transition layer is welded using the following conditions: AC current 410A, front wire voltage 48V, front wire welding speed 46cm / min, and the angle between the front wire and the welding direction 90° (the line energy of the front wire welding transition layer is 25.67kJ / cm). The welding speed is then adjusted as follows: AC current 410A, front wire voltage 48V, front wire welding speed 46cm / min, and the angle between the front wire and the welding direction 90°; DC reverse polarity current 375A, rear wire voltage 46V, rear wire welding speed 46cm / min, and the angle between the rear wire and the welding direction 110°. The composite layer is welded with the front and rear wires 65mm apart in the direction parallel to the weld bead and 15mm apart in the direction perpendicular to the weld bead (the line energy of the rear wire is 23.20kJ / cm when welding the first composite layer; the line energy of the front wire is 25.67kJ / cm and the line energy of the rear wire is 23.20kJ / cm when welding the second composite layer). During the welding process, a transition layer is first welded using the front wire, then the remaining transition layer is welded using the front wire while the first composite layer is welded using the rear wire; finally, the second composite layer is welded using both the front and rear wires simultaneously. The front and rear wires are staggered by 1 / 2 weld bead in the direction perpendicular to the welding direction. (Additional details omitted). Figure 1 As shown; at the same time, when welding the composite layer, the front wire should overlap with the front wire by 1 / 3 to 1 / 2; similarly, when welding the composite layer, the rear wire should overlap with the front wire by 1 / 3 to 1 / 2; after completing the welding of the transition layer and the first composite layer, immediately perform hydrogen removal treatment at 320℃ for 30 minutes, and the interlayer temperature should be <100℃.

[0048] Example 2

[0049] The welding was performed according to the method of Example 1, except that the front wire current was AC and the rear wire current was DC reverse current. The transition layer was welded using the following conditions: AC current of 400A, front wire voltage of 47V, front wire welding speed of 45cm / min, and the angle between the front wire and the welding direction of 90° (the line energy of the front wire welding the transition layer was 25.07kJ / cm); the welding was performed using the following conditions: AC current of 400A, front wire voltage of 47V, front wire welding speed of 45cm / min, and the angle between the front wire and the welding direction of 90°; the DC reverse current was 37... Welding composite layers under the following conditions: 0A, rear wire voltage 47V, rear wire welding speed 45cm / min, rear wire angle with welding direction 110°, distance between front and rear wires in the parallel weld direction 68mm, and distance between front and rear wires in the perpendicular weld direction 15mm (the line energy of the rear wire is 23.19kJ / cm when welding the first composite layer; the line energy of the front wire is 25.07kJ / cm and the line energy of the rear wire is 23.19kJ / cm when welding the second composite layer); the front and rear wires are staggered by 1 / 2 weld bead in the direction perpendicular to the welding direction. (Additional information follows.) Figure 1As shown; at the same time, when welding the composite layer, the front wire should overlap with the front wire by 1 / 3 to 1 / 2; similarly, when welding the composite layer, the rear wire should overlap with the front wire by 1 / 3 to 1 / 2; after completing the welding of the transition layer and the first composite layer, immediately perform hydrogen removal treatment at 320℃ for 30 minutes, and the interlayer temperature should be <100℃.

[0050] Example 3

[0051] The welding was performed according to the method of Example 1, except that the front wire current was AC and the rear wire current was DC reverse current. The transition layer was welded using the front wire with an AC current of 420A, a front wire voltage of 48V, a front wire welding speed of 47cm / min, and an angle of 90° between the front wire and the welding direction (the line energy of the front wire welding the transition layer was 25.74kJ / cm). The welding was performed with an AC current of 420A, a front wire voltage of 48V, a front wire welding speed of 47cm / min, and an angle of 90° between the front wire and the welding direction; the DC reverse current was 390... A. Welding composite layers under the following conditions: Rear wire voltage 48V, rear wire welding speed 47cm / min, rear wire angle to welding direction 110°, front and rear wire distance 70mm along the parallel weld bead direction, and front and rear wire distance 15mm along the perpendicular weld bead direction (welding the first composite layer with a rear wire line energy of 23.90kJ / cm; welding the second composite layer with a front wire line energy of 25.74kJ / cm and a rear wire line energy of 23.90kJ / cm); the front and rear wires should be staggered by 1 / 2 weld bead in the direction perpendicular to the welding direction. (Additional information follows.) Figure 1 As shown; at the same time, when welding the composite layer, the front wire should overlap with the front wire by 1 / 3 to 1 / 2; similarly, when welding the composite layer, the rear wire should overlap with the front wire by 1 / 3 to 1 / 2; after completing the welding of the transition layer and the first composite layer, immediately perform hydrogen removal treatment at 320℃ for 30 minutes, and the interlayer temperature should be <100℃.

[0052] Comparative Example 1

[0053] Using a Q345R material workpiece with dimensions of 600mm×400mm×26mm as the welding object, the 20mm area on both sides of the welding area of ​​the workpiece is ground to remove rust, oxide scale and oil stains; shielded metal arc welding is used, with A302 welding rod for the transition layer and A102 welding rod for the composite layer, with a diameter of 4.0mm. The welding rods need to be dried at 350℃ for 2 hours before welding; the welding current is 165A, the voltage is 25V, and the welding speed is 12cm / min.

[0054] Use A302 welding rods to build up the transition layer, and clean and grind the arc initiation and termination points of each welding rod as well as the interlayer passes;

[0055] Use A102 welding rods to build up the composite layer, and clean and grind the arc initiation and termination points of each welding rod as well as the interlayer passes.

[0056] Comparative Example 2

[0057] Using a Q345R material workpiece with dimensions of 600mm×400mm×26mm as the welding object, the 20mm area on both sides of the welding joint of the workpiece was ground to remove rust, oxide scale and oil stains; gas metal arc welding was used, with E309LT0-1 flux-cored welding wire for the transition layer and E308LT1-1 flux-cored welding wire for the composite layer; the diameter was 1.2mm, the current was 185A, the voltage was 23V, and the welding speed was 22cm / min.

[0058] Comparative Example 3

[0059] The welding was performed according to the method in Example 1, except that the AC current of the front wire was 410A, the voltage of the front wire was 48V, the welding speed of the front wire was 58cm / min, and the angle between the front wire and the welding direction was 90°; the DC reverse current of the rear wire was 375A, the voltage of the rear wire was 46V, the welding speed of the rear wire was 58cm / min, the angle between the rear wire and the welding direction was 110°, and the distance between the front wire and the rear wire was 65mm.

[0060] Comparative Example 4

[0061] The welding was performed according to the method in Example 1, except that the AC current of the front wire was 550A, the voltage of the front wire was 48V, the welding speed of the front wire was 46cm / min, and the angle between the front wire and the welding direction was 90°; the DC reverse current of the rear wire was 500A, the voltage of the rear wire was 46V, the welding speed of the rear wire was 46cm / min, the angle between the rear wire and the welding direction was 110°, and the distance between the front wire and the rear wire was 65mm. The double-wire double-arc submerged arc welding was performed under these conditions.

[0062] The weld sections obtained from the double-arc submerged arc welding of Examples 1-3 and Comparative Examples 1-4 were ground smooth with a grinding wheel, polished with sandpaper, and mechanically polished with diamond abrasive paste until the surface was mirror-like. The weld joint section was etched with a 4% nitric acid alcohol solution, and the macroscopic metallographic structure of the weld section was observed under a metallographic microscope. The base metal fusion and weld overlay areas in the macroscopic metallographic photographs were colored using Photoshop CS6, and the cross-sectional area of ​​the weld and the cross-sectional area of ​​the molten base metal were calculated to determine the fusion ratio. The results are listed in Table 1. Figure 2 The image shows a macroscopic metallographic photograph of the weld seam after dyeing treatment, as shown in Example 1.

[0063] Table 1. Fusion ratios of welds obtained in Examples 1-3 and Comparative Examples 1-4

[0064] Example Penetration depth (mm) Residue height (mm) Melt ratio (%) Example 1 2.2 3.1 30.55 Example 2 2.0 2.8 29.72 Example 3 2.3 3.1 30.92 Comparative Example 1 2.0 2.2 28.33 Comparative Example 2 1.9 1.8 27.51 Comparative Example 3 2.1 2.0 32.75 Comparative Example 4 3.4 3.1 36.1

[0065] Combining Table 1 and Figure 2 It can be seen that the surfacing weld obtained by the welding method provided by this invention has a low fusion ratio, which meets the process requirements of surfacing. Although Comparative Example 3 uses a double-wire double-arc submerged arc welding method, the welding speed is adjusted too quickly, the reinforcement height is reduced, and the fusion ratio is increased, which fails to meet the quality requirements of surfacing. Although Comparative Example 4 uses a double-wire double-arc submerged arc welding method, by increasing the welding current, the penetration depth is increased, and the fusion ratio is increased, which also fails to meet the requirements of surfacing.

[0066] The metallographic microstructure of the weld sections obtained in Example 1 and Comparative Example 4 was examined, and metallographic micrographs were obtained, as shown below. Figure 3 and Figure 4 As shown. Figure 3 The images shown are metallographic micrographs of the weld cross-section obtained in Example 1, where (a) is a metallographic micrograph of the alloy steel side and (b) is a metallographic micrograph of the interface of the fusion zone. Figure 4 The image shows the metallographic microstructure of the weld section obtained in Comparative Example 4. (c) is the metallographic micrograph of the alloy steel side, and (d) is the metallographic micrograph of the fusion zone interface. Figure 3 It can be seen that the weld metal is an austenitic structure containing an appropriate amount of ferrite phase. The ferrite is embedded in the austenitic structure in a skeleton-like or fine strip-like form. This ferrite can improve the strength of the weld overlay and optimize its overall performance. In the fusion zone of the sample, the weld overlay is well bonded to the base metal, and no defects such as cracks are observed. Figure 4 It can be seen that due to the excessive fusion ratio, the weld metal is excessively diluted by the low alloy steel base material, which reduces the austenite-forming elements. Martensite structure appears at the transition layer interface of the weld, resulting in poor toughness of the transition layer interface and the appearance of bending cracks.

[0067] The performance of the welds obtained in Examples 1-3 and Comparative Examples 1-4 was tested according to NB / T47014-2011. The UT performance and PT performance were performed according to NB / T47013.3-2005. The results are listed in Table 2.

[0068] Table 2 shows the performance of the welds obtained in Examples 1-3 and Comparative Examples 1-4.

[0069]

[0070] As can be seen from Table 2, the weld obtained by the welding method provided by the present invention has excellent performance and meets the mechanical properties and microstructure requirements of the weld overlay metal.

[0071] The elemental composition of the weld obtained in Example 1 was analyzed by spectrochemical composition analysis, and the results are listed in Table 3.

[0072] Table 3 Chemical composition of the corrosion-resistant weld overlay metal obtained in Example 1

[0073]

[0074] Note: The standard value refers to the chemical composition of the weld overlay metal, which should meet the acceptable chemical composition of the composite layer H0Cr21Ni10 welding wire.

[0075] As shown in Table 3, according to the chemical composition analysis test of the weld overlay metal for the welding process qualification of pressure equipment in NB / T47014-2011, the weld overlay metal using double-wire submerged arc welding meets the chemical composition requirements of the composite layer H0Cr21Ni10 welding wire.

[0076] Example 1 and Comparative Examples 1 and 2 were welded together for 1m. 2 A comparative analysis was conducted on the consumption and time of welding materials with an area and thickness of 8mm, and the results are listed in Table 4.

[0077] Table 4 Comparison of welding material consumption and time in Example 1 and Comparative Examples 1 and 2

[0078]

[0079]

[0080] As shown in Table 4, the welding material cost for Example 1 was 4723.87 yuan, while the welding material cost for shielded metal arc welding in Comparative Example 1 was 4524 yuan. Therefore, under the premise of comparable welding material costs, the use of double-wire double-arc submerged arc welding can improve efficiency by more than 10 times while reducing the workload of welders and effectively improving the working environment.

[0081] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for overlaying welding, comprising the following steps: The workpiece is fixed to a dual-wire dual-arc submerged arc welding equipment and surfacing is performed using dual-wire dual-arc submerged arc welding; the thickness of the workpiece is 26mm. The dual-wire dual-arc submerged arc welding includes front wire welding and rear wire welding. The conditions for front wire welding include: front wire current is alternating current, the alternating current is 400-420A, front wire voltage is 46-48V, front wire welding speed is 45-47cm / min, and the angle between the front wire and the welding direction is 90°. The conditions for back wire welding include: the back wire current is a DC reverse current, the DC reverse current is 350-450A, the back wire voltage is 46-48V, the back wire welding speed is 45-47cm / min, and the angle between the back wire and the welding direction is 110-115°. The front and rear wires are 60-75mm apart along the direction parallel to the weld bead; the front and rear wires are 10-15mm apart along the direction perpendicular to the weld bead. The weld overlay includes a layered transition layer and a composite layer; the composite layer includes a first composite layer and a second composite layer. When performing double-wire double-arc submerged arc welding, the front wire is used to weld the transition layer, and the rear wire is used to weld the first composite layer; the front wire and the rear wire are used to weld the second composite layer.

2. The welding method according to claim 1, characterized in that, The conditions for front wire welding include: the front wire current is an alternating current of 410-420A, the front wire voltage is 47V, the front wire welding speed is 46cm / min, and the angle between the front wire and the welding direction is 90°. The conditions for back wire welding include: the back wire current is a DC reverse current, the DC reverse current is 375~385A, the back wire voltage is 47V, the back wire welding speed is 46cm / min, and the angle between the back wire and the welding direction is 110~115°.

3. The welding method according to claim 1, characterized in that, The number of welding passes for the front wire is one more than the number of welding passes for the rear wire, and the number of welding passes for the front wire is 2 to 3.

4. The welding method according to any one of claims 1 to 3, characterized in that, The diameters of the front and back filaments are independently 4–6 mm.

5. The welding method according to claim 4, characterized in that, Before performing surfacing using dual-wire dual-arc submerged arc welding, the process also includes: grinding the workpiece; cleaning and drying the front and rear wires respectively; The drying temperature is 300-400℃, and the drying time is 1.8-2.2h.

6. The welding method according to claim 1, characterized in that, After obtaining the transition layer and the first composite layer, hydrogen removal treatment is performed.

7. The welding method according to claim 6, characterized in that, The hydrogen removal treatment is performed at a temperature of 300–350°C for 28–32 minutes.

8. The welding method according to claim 1, characterized in that, The material of the weldment is alloy steel; the alloy steel is Q345R.

9. The welding method according to claim 8, characterized in that, When welding the transition layer, the front wire is H10Cr24Ni13 welding wire; When welding the first composite layer, the welding wire used is H0Cr21Ni10 welding wire; When welding the second composite layer, the front wire is H0Cr21Ni10 welding wire, and the rear wire is H0Cr21Ni10 welding wire.

10. The welding method according to claim 8 or 9, characterized in that, The flux used in the dual-wire dual-arc submerged arc welding is SJ601 flux.

Images