High-strength steel welding methods

Abstract

The application discloses a high-strength steel welding method, which comprises the following steps: splicing a first connecting steel piece and a second connecting steel piece to form a groove; performing backing welding on the first connecting steel piece and the second connecting steel piece, and the welding wire is a plurality of twisted welding wires; and performing filling welding and / or surface covering welding on the first connecting steel piece and the second connecting steel piece by adopting a double-wire three-arc welding mode, and the welding wire is a plurality of twisted welding wires. In the high-strength steel welding method, the root fusion property is effectively improved in the backing welding, the fusion property of the root weld toe position is improved, the root quality of the welded joint is ensured, the filling welding and / or surface covering welding can avoid the influence on the weld metal of the backing welding under the condition of ensuring a high welding speed and a high deposition efficiency, the overheating phenomenon at the connecting position is avoided, low deformation welding is ensured, and the risk of quenching cracking is avoided, and the rotating arc of the plurality of twisted welding wires can significantly reduce or even eliminate large particle spatter.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, in particular to a high-strength steel welding method. Background Art

[0002] High-strength steel with a yield strength of 690 MPa or above is widely used in engineering machinery structures such as arms, legs, and chassis, as well as large ships and marine engineering structures due to its good weight reduction and environmental friendliness.

[0003] Currently, when welding high-strength or ultra-high-strength steel, especially for steel plates thicker than 4mm, the current used in MAG welding is typically below 180A (amperes) to facilitate arc control. This allows for short-circuit transfer of the droplet, minimizing the chance of leaks. However, this low current can lead to poor root fusion, resulting in a depression at the back of the weld toe, which compromises joint strength. High-energy beam welding (such as laser welding) is often used to improve efficiency in welding high-strength or ultra-high-strength steel. However, due to the rapid cooling rate, high-energy beam welding can lead to a greater tendency for the high-strength steel to harden, increasing the risk of cracking. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a high-strength steel welding method, which has high welding efficiency and high welding strength and avoids the problem of quenching cracking.

[0005] The present invention provides a high-strength steel welding method, comprising:

[0006] Splicing the first connecting steel member and the second connecting steel member to form a groove;

[0007] Performing bottom welding on the first connecting steel member and the second connecting steel member, wherein the welding wire for the bottom welding is a multi-strand twisted welding wire; and

[0008] The first connecting steel member and the second connecting steel member are subjected to filler welding and / or cap welding by adopting a double-wire three-arc welding method, and the welding wires for the filler welding and / or cap welding are multi-strand twisted wires.

[0009] In one embodiment, the high-strength steel welding method further includes: before performing the bottom welding, spot welding the first connecting steel member and the second connecting steel member.

[0010] In one embodiment, the groove formed between the first connecting steel member and the second connecting steel member is a V-shaped groove, the groove angle of the groove is 30-45°, the blunt edge is 0-2 mm, and the root gap is 0-2 mm.

[0011] In one embodiment, in the root welding, the welding current is 220-260A, the voltage is 26-28V, and the welding speed is 400-500mm / min.

[0012] In one embodiment, in the bottom welding, a first welding gun is used for welding, the angle between the first welding gun and the welding direction is 15 to 30 degrees, and the first welding gun is tilted toward the rear of the forward direction of the first welding gun.

[0013] In one embodiment, in the filler welding and / or cap welding, the wire feeding speed of the two welding wires is 12-15 m / min, the current of the two welding wires is 300-400 A, the voltage is 40-45 V, the intermediate arc current is 100-200 A, the voltage is 58-68 V, and the welding speed is 700-800 mm / min.

[0014] In one embodiment, in the fill welding and / or cap welding, the arc switching frequency is 100-110 Hz, and the duty cycle is 40-60%.

[0015] In one embodiment, in the filling welding and / or cap welding, a second welding gun is used for welding, and the second welding gun is perpendicular to the first connecting steel member and the second connecting steel member.

[0016] In one embodiment, in the bottom welding, the dry extension length of the welding wire is 10 to 20 mm; in the filling welding and / or cap welding, the dry extension length of the welding wire is 15 to 20 mm.

[0017] In one embodiment, the welding current during the fill welding and / or cap welding is greater than the welding current during the root welding, and the welding speed of the fill welding and / or cap welding is greater than the welding speed of the root welding.

[0018] In the high-strength steel welding method provided by the embodiment of the present invention, multi-strand twisted welding wires are used to perform base welding and filling welding and / or cover welding in sequence, and the filling welding and / or cover welding adopt double-wire three-arc welding. The stirring effect of the multi-strand twisted welding wire on the molten pool can effectively improve the root fusion in the base welding, thereby improving the fusion of the root weld toe position and ensuring the root quality of the weld joint; the filling welding and / or cover welding can achieve low heat input while ensuring a high welding speed and cladding efficiency, avoid affecting the weld metal of the base welding, avoid overheating at the connection, ensure welding with low deformation, and do not need to use high-energy beam welding, and also avoid the risk of quenching cracking; the rotating arc of the multi-strand twisted welding wire in the base welding and filling welding and / or cover welding enhances the directionality of the welding droplet transfer, the welding process is more stable, and large particle spatter is significantly reduced or even eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Flowchart of a high-strength steel welding method according to an embodiment of the present invention.

[0021] Figure 2 for Figure 1 Schematic diagram of the structure of the first connecting steel part and the second connecting steel part to be welded in the medium- and high-strength steel welding method.

[0022] Figure 3(a) is a schematic diagram of the structures of several equal-diameter welding wires.

[0023] Figure 3(b) is a schematic diagram of the structures of several non-uniform diameter welding wires.

[0024] Figure 3(c) is a schematic diagram of the structures of several composite welding wires.

[0025] Figure 3(d) is a schematic diagram of the structure of a small-strand single-filament welding wire that is entirely solid.

[0026] FIG3(e) is a schematic diagram showing the structure of a small strand of single wire in which part of the wire is solid welding wire and part of the wire is flux-cored welding wire.

[0027] Figure 3(f) is a schematic diagram of the structure of a small-strand single-filament flux-cored welding wire.

[0028] Figure 3(g) is a schematic diagram of the structure of another type of small-strand single-filament flux-cored welding wire.

[0029] Figure 3(h) is a schematic diagram of the structure of another type of small-strand single-filament welding wire that is entirely solid.

[0030] FIG3(i) is a schematic diagram showing the structure of another type of small-strand single-filament welding wire that is entirely solid.

[0031] Figure 3(j) is a schematic diagram of the three-dimensional structure of a small-strand single-filament welding wire that is entirely solid.

[0032] Figure 4 for Figure 1 Schematic diagram of the welding structure of the welding gun in the root welding method of medium and high strength steel.

[0033] Figure 5 for Figure 1 Schematic diagram of the welding structure of the welding gun in the filling welding and / or cap welding of medium and high strength steel.

[0034] FIG6(a) and FIG6(b) are schematic diagrams of the filler weld and / or cap weld.

[0035] FIG7( a ) is a front view of a weld after welding according to an embodiment of the present invention.

[0036] FIG7( b ) is a back view of the weld after welding according to an embodiment of the present invention.

[0037] FIG7( c ) is a cross-sectional view of a weld after welding according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, and not all, of the embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the description of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0039] In the description of the present invention, unless otherwise specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms based on the specific circumstances.

[0040] The directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0041] The terms "first," "second," "third," etc. are merely used to distinguish elements of similar nature and do not indicate or imply relative importance or a particular order.

[0042] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than the listed elements and may also include additional elements not specifically listed.

[0043] Compared with low-strength steel, high-strength steel has a larger carbon equivalent and is more sensitive to welding heat input and cooling time.

[0044] Please refer to Figure 1 A high-strength steel welding method provided in one embodiment of the present invention comprises the following steps:

[0045] S11, please refer to Figure 2 The first connecting steel piece 11 and the second connecting steel piece 13 are spliced to form a groove, and the first connecting steel piece 11 and the second connecting steel piece 13 are spot-welded. It can be understood that the first connecting steel piece 11 and the second connecting steel piece 13 can also be clamped by a tool without spot-welding.

[0046] S13, the first connecting steel piece 11 and the second connecting steel piece 13 are prepared for welding, and the welding wire of the backing welding is a multi-strand twisted welding wire.

[0047] S15, the first connecting steel piece 11 and the second connecting steel piece 13 are filled and / or covered by using a double-wire three-arc welding method, and the welding wire of the filling and / or covering welding is a multi-strand twisted welding wire. The welding material of the filling and / or covering welding is covered on the welding material of the backing welding. It can be understood that the double-wire three-arc welding can be used in both the filling and the covering welding, or the double-wire three-arc welding method can be used only in the filling or the covering welding.

[0048] In the backing welding process, when a conventional high-strength steel solid welding wire is used, the current used is generally below 180A. When the current is large, the molten droplet will accumulate above the root metal when it solidifies, so that a depression will be formed at the back weld toe, which will affect the fatigue properties of the welded structure, and the depression will be the starting position of the later cracking. When a smaller current is used, the arc energy is insufficient, and the sidewall penetration is small, which will also reduce the load-bearing capacity of the welded structure. In the embodiment of the present application, a multi-strand twisted welding wire is used in the backing welding process. The multi-strand twisted welding wire is twisted by rotating a plurality of small-diameter welding wires. When welding, the arc has obvious rotation characteristics, and the arc has obvious stirring effect on the molten pool. The arc force is large, which can fully melt the root metal and avoid the occurrence of back metal depression. When applied in the scene of single-sided welding and double-sided forming, the columnar crystal can be broken on the basis of realizing single-sided welding and double-sided forming, which is helpful to refine the grain and improve the mechanical properties of the weld.

[0049] In the filling welding and / or cover welding process, if the conventional MAG welding is used, the welding efficiency is low, especially in the filling welding process, which will be stacked layer by layer, and more time is needed. If the high-energy beam welding method is used, although the efficiency is improved, but the too fast cooling speed is not friendly to high-strength steel, which produces hardened structure and increases the risk of cracking of the structure. When using tandem double-wire welding, two welding wires send molten droplets into the molten pool alternately, which also brings more energy input, which will cause more serious secondary heating to the base metal of the backing welding, thereby producing larger grains and softening phenomenon in the heat-affected zone. In the embodiment of the application, a double-wire three-arc welding method is adopted, which is based on the conventional double-wire double-arc welding, and an intermediate arc M is formed between the two wires through the dynamic control method of the power supply. During welding, in the first half cycle, please refer to Figure 6(a), the first arc H1 is formed between the left wire and the workpiece, and the intermediate arc M is formed between the left wire and the right wire. After the current passes through the left wire, part of the current I L flows through the workpiece to send energy into the molten pool, at the same time, part of the current I M flows through the intermediate arc M and the right wire, and the heat of this part of the current does not enter the molten pool, but participates in the melting of the weld droplet; in the second half cycle, please refer to Figure 6(b), the second arc H2 is formed between the right wire and the workpiece, and the intermediate arc M is formed between the left wire and the right wire. Part of the current I R flows through the workpiece to send energy into the molten pool, at the same time, part of the current I M flows through the intermediate arc M and the left wire, and the heat of this part of the current does not enter the molten pool, but participates in the melting of the weld droplet. This is alternately carried out in turn, so as to realize the melting of the droplet with sufficient energy, but part of the energy enters the molten pool, so as to realize the low dilution rate of the base metal surface of the backing welding and the non-overheating of the molten metal, the total heat input into the molten pool is small, and the welding with high speed, low heat input and low deformation is realized. It can be seen that in the double-wire three-arc welding, multiple loops need to be formed continuously, especially between the main arc and the intermediate arc in a certain half cycle, electromagnetic interference exists, and in the actual welding process, arc instability and large spatter occur. In the embodiment of the application, a plurality of twisted welding wires are used as welding materials for cover welding and / or filling welding, and the arc rotation and strong stiffness characteristics of the plurality of twisted welding wires in the welding process are beneficial to the timely shedding of the droplet, so as to ensure the stability of the welding process and reduce or even eliminate the generation of large particles.

[0050] In summary, it can be seen that in the high-strength steel welding method of this embodiment, when welding high-strength steel, multi-strand twisted welding wires are used to perform base welding and filling welding and / or cover welding in sequence, and the filling welding and / or cover welding adopt double-wire three-arc welding. The stirring effect of the multi-strand twisted welding wire on the molten pool can effectively improve the root fusion in the base welding, thereby improving the fusion of the root weld toe position and ensuring the root quality of the weld joint; the filling welding and / or cover welding can achieve low heat input while ensuring a high welding speed and cladding efficiency, avoid affecting the weld metal of the base welding, avoid overheating at the connection, ensure welding with low deformation, and do not need to adopt high-energy beam welding, and also avoid the risk of quenching cracking; the rotating arc of the multi-strand twisted welding wire in the base welding and filling welding and / or cover welding enhances the directionality of the welding droplet transition, the welding process is more stable, and large particle spatter is significantly reduced or even eliminated. The use of twin-wire triple-arc welding for filler and / or cap welding is particularly friendly to the welding of high-strength steel. Due to the lower heat input and smaller grain size, the performance of the welded joint can be improved. In addition, the welding speed of twin-wire triple-arc welding can be doubled or even tripled compared to the conventional MAG (Metal Active-Gas Arc Welding) welding method.

[0051] In this embodiment, the groove formed between the first connecting steel member 11 and the second connecting steel member 13 can be a V-shaped groove, with a groove angle α of 30 to 45°, a blunt edge L1 of 0 to 2 mm, and a root gap L2 of 0 to 2 mm. It is understood that the groove can also be a single-sided V-shaped groove, a Y-shaped groove, or a U-shaped groove, without limitation. In this embodiment, the first connecting steel member 11 and the second connecting steel member 13 are both steel plates with a thickness of at least 4 mm, and are made of high-strength steel with a yield strength of 690 MPa or higher.

[0052] Specifically, in step S11, before the first connecting steel member 11 and the second connecting steel member 13 are spliced ​​together to form a groove, the first connecting steel member 11 and the second connecting steel member 13 are processed to form a first groove bevel 112 at one end of the first connecting steel member 11, and a second groove bevel 132 at one end of the second connecting steel member 13. The first groove bevel 112 and the second groove bevel 132 are spaced apart and arranged relative to each other to form the above-mentioned groove.

[0053] In this embodiment, single-wire MAG welding is used for the root pass welding in step S13. Specifically, the MAG welding current is 220-260A, the voltage is 26-28V, and the welding speed is 400-500mm / min. The current used in MAG welding can be a MIG power supply. Here, a multi-stranded wire is used, and corresponding parameters such as current, voltage, and welding speed are coordinated. During welding, the increased current improves welding efficiency, and the arc exhibits a significant rotational characteristic, stirring the molten pool. The high arc force not only fully melts the root metal and prevents the formation of back metal depressions, but also breaks up columnar crystals, helping to refine the grain size. This results in a high-quality, reliable high-strength steel welded root pass joint and improves the mechanical properties of the weld.

[0054] For details, please refer to Figure 3(a) to Figure 3(j) The welding wire used in the bottom pass welding is formed by twisting together a plurality of small strands of single wire 15. Specifically, the diameters of the plurality of small strands of single wire 15 can be the same (as shown in FIG3(a)) or different (as shown in FIG3(b)). One or more of the plurality of small strands of single wire 15 can be solid welding wire or flux-cored welding wire. In other words, the plurality of small strands of single wire 15 can all be solid welding wire (as shown in FIG3(d)), or all be flux-cored welding wire (as shown in FIG3(f) and FIG3(g)), or some can be solid welding wire and some can be flux-cored welding wire (as shown in FIG3(e)). Specifically, the welding wire used in the bottom pass welding can be made of high-strength steel.

[0055] Specifically, the diameter of the welding wire used in the bottom pass welding can be 1.2 mm. Of course, the diameter of the welding wire used in the bottom pass welding can also be other sizes, which are not limited here.

[0056] Please refer to Figure 4 Specifically, during the root pass welding, the first welding torch 17 is used for welding. The first welding torch 17 can be moved along a first direction to form a weld. The center of the welding wire is aligned with the center of the groove and the first direction.

[0057] Specifically, during the root welding, the angle β between the first welding gun 17 and the first connecting steel member 11 and the second connecting steel member 13 is 15-30°, and the first welding gun 17 is tilted toward the rear of the forward direction of the first welding gun 17. The welding wire dry extension is 10-20 mm.

[0058] In this embodiment, step S15 specifically includes the following steps:

[0059] S151, using a double-wire triple arc welding method to perform filler welding on the first connecting steel member 11 and the second connecting steel member 13, using a multi-strand twisted wire as the welding wire for the filler welding. The filler welding can be performed in one pass, two passes, or more.

[0060] S153: Cap welding is performed on the first and second connecting steel members 11, 13 using a double-wire, triple-arc welding method. The cap welding wire is a multi-stranded wire. The cap welding is performed in one pass. If the thickness of the first and second connecting steel members 11, 13 is relatively small, step S151 can be omitted, and the cap welding can be performed directly after the base welding. In other words, the filler weld and / or cap weld can include both the filler weld and the cap weld, or can consist of only the cap weld.

[0061] Specifically, in the filling welding and / or cap welding of step S15, in the double-wire triple-arc welding method, the wire feeding speed V of the two welding wires is 12-15 m / min, the current of the two welding wires is 300-400 A, the voltage is 40-45 V, the intermediate arc current is 100-200 A, the voltage is 58-68 V, and the welding speed is 700-800 mm / min. In the filling welding and / or cap welding, due to the use of the double-wire triple-arc welding method, on the one hand, the welding efficiency is improved, and on the other hand, a third arc is formed between the two welding wires. The two welding wires weld alternately, achieving sufficient energy to melt the molten droplets, but only part of the energy enters the molten pool, and the other part of the energy is taken away by the third arc. In this way, while ensuring a high welding speed and cladding efficiency, a low energy heat input can be achieved, thereby achieving a low dilution rate for the surface layer of the bottom weld metal, so that the molten metal of the bottom weld will not be overheated, and the total heat input into the molten pool is also small, achieving high-speed, low heat input and low deformation welding. At the same time, the arc rotation and strong stiffness of the multi-strand twisted welding wire during the welding process are beneficial to the timely shedding of the molten droplets, thereby ensuring the stability of the welding process and reducing or even eliminating the generation of large particle spatter.

[0062] Specifically, in the filling welding and / or cap welding in step S15 , the arc switching frequency may be 100-110 Hz, and the duty cycle may be 40-60%.

[0063] Specifically, the welding wire used in the filler weld and / or cap weld is also formed by twisting together multiple small strands of single wire 15. Its structure is essentially the same as that of the welding wire used in the root weld, and will not be described in detail here. Specifically, the filler weld and / or cap weld can use welding wire of the same specifications and dimensions as the root weld. This ensures that the material of the resulting weld remains consistent, thereby ensuring higher strength consistency across the weld.

[0064] Please refer to Figure 5 Specifically, during the filling welding and / or cap welding, the second welding gun 19 is used for welding, and the second welding gun 19 can be moved along the first direction to form the weld. The connecting line of the two welding wires and the first direction are located on the same straight line.

[0065] Specifically, during the filler weld and / or cap weld, the second welding torch 19 is perpendicular to the first and second connecting steel members 11, 13. The welding wire extension is 15 to 20 mm. More specifically, both welding wires of the second welding torch 19 are tilted relative to the first and second connecting steel members 11, 13, with their ends proximal to the first and second connecting steel members 11, 13 being positioned close to each other.

[0066] In the first half of the filler welding and / or cap welding cycle, refer to Figure 6(a). A first arc H1 is formed between the left welding wire and the workpiece, and an intermediate arc M is formed between the left welding wire and the right welding wire. After the current passes through the left welding wire, part of the current I L Flows through the workpiece, delivering energy into the molten pool. At the same time, part of the current I M The heat of this part of the current does not enter the molten pool, but participates in the melting of the weld droplet. In the second half of the cycle, please refer to 6(b), a second arc H2 is formed between the right welding wire and the workpiece, and an intermediate arc M is formed between the left and right welding wires. Part of the current I R Flows through the workpiece, delivering energy into the molten pool. At the same time, part of the current I M The heat from this current, which flows through the wire, the middle arc M, and the left wire, isn't delivered to the molten pool, but it contributes to the melting of the weld droplets. This alternating process ensures sufficient energy to melt the droplets, but some of this energy enters the molten pool. This ensures high welding speeds and cladding efficiency while also reducing energy and heat input, resulting in a lower dilution rate for the surface layer of the root weld metal. This prevents overheating of the molten metal, and minimizes the total heat input to the molten pool, enabling high-speed, low-heat-input, and low-distortion welding.

[0067] A high-strength steel welding method according to an embodiment is described below.

[0068] Example 1:

[0069] S21, a first bevel 112 is formed at one end of the first connecting steel member 11, and a second bevel 132 is formed at one end of the second connecting steel member 13, the first bevel 112 and the second bevel 132 are spaced apart and arranged relative to each other to form a bevel, the bevel is a V-shaped bevel, the bevel angle α is 30°, the blunt edge L1 is 1 mm, the root gap L2 is 1 mm, the thickness of the steel plate is 8 mm, and the steel plate is made of high-strength steel with a yield strength of 890 MPa.

[0070] S23, performing bottom welding on the first connecting steel member 11 and the second connecting steel member 13, wherein the welding wire for the bottom welding is a multi-strand twisted wire, wherein the current of MAG welding is 220A, the voltage is 26V, and the welding speed is 400mm / min.

[0071] S25, a double-wire three-arc welding method is used to perform filling welding and / or cover welding on the first connecting steel part 11 and the second connecting steel part 13, and the welding wire for the filling welding and / or cover welding is a multi-strand twisted welding wire, wherein the wire feeding speed V of the two welding wires is 14m / min, the current of the two welding wires is 360A, the voltage is 43V, the intermediate arc current is 200A, the voltage is 65V, and the welding speed is 780mm / min.

[0072] After welding using the high-strength steel method described above, as shown in Figures 7(a) and 7(b), both the front and back metals are relatively smooth, demonstrating that the root and cover welding processes are stable and spatter-free when using multi-stranded wire as the cladding material. Figure 7(c) shows a deep penetration at the root, demonstrating good fusion. The back reinforcement is within 1 mm, and the weld toe is completely melted. After tensile, bending, and impact testing, the mechanical properties meet the requirements for use.

[0073] The present invention also provides high-strength steel welding equipment, comprising a first welding gun 17 and a second welding gun 19. The first welding gun 17 is used for root welding, and the second welding gun 19 is used for filler welding and / or cap welding. The first welding gun 17 is equipped with a first welding wire, which is a multi-strand stranded welding wire. The second welding gun 19 is equipped with two second welding wires, which are also multi-strand stranded welding wires. The second welding gun 19 is a twin-wire triple-arc welding gun.

[0074] In this embodiment, the first welding gun 17 can be a MAG welding device. Specifically, the welding current of the first welding gun 17 is 220-260A, the voltage is 26-28V, and the welding speed is 400-500mm / min. Here, using a multi-stranded welding wire and matching corresponding parameters such as current, voltage, and welding speed, the increased current improves welding efficiency during welding. The arc exhibits a significant rotational characteristic, stirring the molten pool. The high arc force not only fully melts the root metal and prevents the formation of back metal depressions, but also breaks up columnar crystals, helping to refine the grain size. This results in a high-quality, reliable high-strength steel welded root joint and improves the mechanical properties of the weld.

[0075] Specifically, the first welding wire is Figure 3(a) to Figure 3(j) The welding wire in the will not be described here.

[0076] Specifically, the angle β between the first welding gun 17 and the first connecting steel member 11 and the second connecting steel member 13 is 15-30 degrees, and the first welding gun 17 is tilted toward the rear of the forward direction of the first welding gun 17. The dry extension length of the first welding wire is 10-20 mm.

[0077] In the embodiment, the wire feeding speed V of the two second welding wires of the second welding torch 19 is 12-15 m / min, the current of the two second welding wires is 300-400 A, the voltage is 40-45 V, the intermediate arc current is 100-200 A, the voltage is 58-68 V, and the welding speed is 700-800 mm / min. In the filling welding and / or the surface welding, the double-wire three-arc welding method is used, on the one hand, the welding efficiency is improved, and on the other hand, the third arc is formed between the two welding wires, the two welding wires are welded alternately, enough energy is used to melt the droplet, but only part of the energy enters the molten pool, and the other part of the energy is taken away by the third arc, so that the high welding speed and the high deposition efficiency are ensured, and the low energy heat input is also realized, so that the low dilution rate is realized on the surface of the base metal, the molten metal of the base welding is not overheated, the total heat input of the molten pool is small, the high-speed low-heat-input and low-deformation welding is realized. At the same time, the arc rotation in the welding process and the strong stiffness of the multi-strand twisted welding wire are used, which is beneficial to the timely falling of the droplet, so as to ensure the stability of the welding process and reduce or even eliminate the generation of large particles.

[0078] Specifically, the arc switching frequency of the second welding torch 19 can be 100-110 Hz, and the duty cycle is 40-60%.

[0079] Specifically, the second welding wire is the welding wire in the Figure 3(a) to Figure 3(j) which will not be described here.

[0080] Specifically, the second welding torch 19 is perpendicular to the first connecting steel piece 11 and the second connecting steel piece 13. The dry length of the second welding wire is 15-20 mm. More specifically, the two second welding wires are inclined relative to the first connecting steel piece 11 and the second connecting steel piece 13, and the ends of the two second welding wires close to the first connecting steel piece 11 and the second connecting steel piece 13 are close to each other.

[0081] It should be noted that each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same parts of each embodiment can be referred to each other.

[0082] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any changes or replacements within the technical range disclosed in the present application can be easily thought by those skilled in the art, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A high-strength steel welding method, characterized in that: Applicable to scenarios of single-sided welding and double-sided forming, including: Splicing the first connecting steel piece (11) and the second connecting steel piece (13) to form a groove; MAG welding is used to perform bottom welding on the first connecting steel member (11) and the second connecting steel member (13), wherein the bottom welding wire is a multi-strand twisted wire; and Performing filler welding and / or cap welding on the first connecting steel member (11) and the second connecting steel member (13) by using a double-wire three-arc welding method, wherein the welding wires for the filler welding and / or cap welding are multi-strand twisted welding wires; The welding current during the filling welding and / or cap welding is greater than the welding current during the root welding, and the welding speed of the filling welding and / or cap welding is greater than the welding speed of the root welding.

2. The high-strength steel welding method according to claim 1, characterized in that: The high-strength steel welding method further comprises: before performing the bottom welding, spot welding the first connecting steel piece (11) and the second connecting steel piece (13).

3. The high-strength steel welding method according to claim 1, characterized in that: The groove formed between the first connecting steel member (11) and the second connecting steel member (13) is a V-shaped groove, the groove angle (α) of the groove is 30 to 45 degrees, the blunt edge (L1) is 0 to 2 mm, and the root gap (L2) is 0 to 2 mm.

4. The high-strength steel welding method according to claim 1, characterized in that: In the base welding, the welding current is 220-260A, the voltage is 26-28V, and the welding speed is 400-500mm / min.

5. The high-strength steel welding method according to claim 1, characterized in that: In the bottom welding, a first welding gun (17) is used for welding, the angle (β) between the first welding gun (17) and the welding direction is 15 to 30 degrees, and the first welding gun (17) is tilted toward the rear of the forward direction of the first welding gun (17).

6. The high-strength steel welding method according to claim 1, characterized in that: In the filling welding and / or cap welding, the wire feeding speed of the two welding wires is 12-15 m / min, the current of the two welding wires is 300-400 A, the voltage is 40-45 V, the intermediate arc current is 100-200 A, the voltage is 58-68 V, and the welding speed is 700-800 mm / min.

7. The high-strength steel welding method according to claim 1, characterized in that: In the filling welding and / or cap welding, the arc switching frequency is 100-110 Hz, and the duty cycle is 40-60%.

8. The high-strength steel welding method according to claim 1, characterized in that: In the filling welding and / or cap welding, a second welding gun (19) is used for welding, and the second welding gun (19) is perpendicular to the first connecting steel member (11) and the second connecting steel member (13).

9. The high-strength steel welding method according to claim 1, characterized in that: In the base welding, the dry extension length of the welding wire is 10 to 20 mm; in the filling welding and / or cap welding, the dry extension length of the welding wire is 15 to 20 mm.

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