Back-gouging-free welding process for butt weld

Abstract

The invention relates to the technical field of welding, in particular to a butt weld back-gouging-free welding process which comprises the steps that S1, blanking and forming of a steel plate are completed, double-face symmetrical grooves are formed in the butt joint weld positions of two to-be-welded plates correspondingly, and a truncated edge is arranged between the grooves in the two sides of the lower to-be-welded plate; s2, the to-be-welded areas of the two to-be-welded plates are ground and derusted through a grinding machine; s3, the two to-be-welded plates are assembled, positioned and welded; s4, preheating the welding seam area; s5, gas protection backing welding is conducted on the two sides of the weld joint at the same time in the same direction, and electric arcs in a fine drop transition or jet flow transition mode are adopted during welding; and S6, gas protection filling and cosmetic welding are conducted on the two sides of the weld joint at the same time in the same direction, and electric arcs in a pulse droplet transition mode are adopted during welding. Therefore, by means of the method, back gouging-free full penetration welding can be achieved, the method can adapt to gap change tolerance in a larger range, and the back gouging technology can be effectively popularized.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and in particular to a butt weld root cleaning-free welding process. Background Art

[0002] At present, the root cleaning-free horizontal welding process for butt welds has very strict assembly requirements and can only adapt to a root gap variation tolerance of 0 to 1 mm at most. Therefore, its application range is very narrow, especially for the welding and manufacturing of large structural parts and thick plates, the automated root cleaning-free horizontal welding process is almost not applicable. Summary of the invention

[0003] The purpose of the present application is to provide a butt weld root cleaning-free welding process, which to a certain extent solves the technical problem that the butt weld root cleaning-free horizontal welding process in the prior art has very strict assembly requirements and can only adapt to a maximum root gap variation tolerance of 0 to 1 mm. Therefore, its application range is very narrow, especially for the welding and manufacturing of large structural parts and thick plates, the automated root cleaning-free horizontal welding process is almost not applicable.

[0004] The present application provides a butt weld root cleaning-free welding process, comprising the following steps:

[0005] S1. Complete the blanking and forming of the steel plate to form two plates to be welded, and open two-sided symmetrical grooves at the weld positions where the two plates to be welded are connected, and a blunt edge is set between the grooves on both sides of the lower plate to be welded;

[0006] S2, grinding and removing rust from the welding areas of the two plates to be welded by a grinding machine;

[0007] S3, assemble and position weld the two plates to be welded to ensure that the butt weld is located at the horizontal welding position;

[0008] S4, preheating the weld area formed between the two plates to be welded before welding;

[0009] S5. Perform gas shielded base welding on both sides of the weld simultaneously and in the same direction, and use arc in the form of droplet transition or jet transition during welding;

[0010] S6. Gas shielded filling and cap welding are carried out simultaneously and in the same direction on both sides of the weld, and pulse droplet transfer arc is used during welding.

[0011] In the above technical solution, further, in step S1, the thickness of the blunt edge between the grooves on both sides of the lower plate to be welded is b, and 6mm≤b≤8mm.

[0012] In any of the above technical solutions, further, in step S1, the thickness of the blunt edge between the grooves on both sides of the upper plate to be welded is a, and 0mm≤a≤2mm.

[0013] In any of the above technical solutions, further, in step S1, when 20mm≤t<80mm, 0mm≤a≤2mm, 6mm≤b≤8mm; when t≥80mm, 1mm≤a≤2mm, 6mm≤b≤8mm.

[0014] In any of the above technical solutions, further, in step S3, the positioning weld is ground before welding to remove welding defects, and the end is ground to form a transition slope, and the error tolerance of the assembly weld is ensured to be 0 to 3 mm, and the root gap tolerance is 0 to 4 mm.

[0015] In any of the above technical solutions, further, in step S5, during the base welding, the front welding gun does not swing, the welding wire end of the front welding gun points to the lower blunt edge line, the angle between the front welding gun and the horizontal plane is 8-10°, the welding current of the front welding gun is 240-280A, the welding voltage of the front welding gun is 27-30V, and the welding speed of the front welding gun is adjusted in real time according to the root gap size of the weld to ensure that the base welding does not burn through.

[0016] In any of the above technical solutions, further, in step S5, when the root gap tolerance of the weld is 0-2mm, the welding speed of the front welding gun is 300mm / min; when the root gap tolerance of the weld is 2-3mm, the welding speed of the front welding gun is 250-300mm / min; when the root gap tolerance of the weld is 3-4mm, the welding speed of the front welding gun is 190-250mm / min.

[0017] In any of the above technical solutions, further, during the base welding process, the front welding gun adjusts the welding speed in real time according to the size of the weld, and the other welding parameters remain unchanged.

[0018] In any of the above technical solutions, further, in step S5, during base welding, the rear welding gun does not swing, the welding wire end of the rear welding gun points to the center of the weld, the welding speed of the rear welding gun is consistent with the welding speed of the front welding gun, and the welding current and welding voltage are adjusted in real time according to the size of the root gap of the weld to ensure that the base weld of the rear gun is formed without sagging.

[0019] In any of the above technical solutions, further, in step S5, when the root gap tolerance of the weld is 0-2mm, the welding current of the rear welding gun is 300-320A, and the welding voltage of the rear welding gun is 30-33V; when the root gap tolerance of the weld is 2-3mm, the welding current of the rear welding gun is 260-300A, and the welding voltage of the rear welding gun is 28-31V; when the root gap tolerance of the weld is 3-4mm, the welding current of the rear welding gun is 220-260A, and the welding voltage of the rear welding gun is 24-28V.

[0020] In any of the above technical solutions, further, during the base welding process, the rear welding gun adjusts the wire feeding speed in real time according to the size of the weld, controls the welding current and welding voltage by the wire feeding speed, and the other welding parameters remain unchanged.

[0021] In any of the above technical solutions, further, in step S6, during the filling and capping welding process, both welding guns use non-swinging multi-layer and multi-pass welding, the welding current of both welding guns is 220-280A, the welding voltage of both welding guns is 24-30V, and the welding speed of both welding guns is 300-320mm / min.

[0022] In any of the above technical solutions, further, the butt weld root cleaning-free welding process also includes the following steps: S7, performing appearance inspection, internal structure inspection and mechanical property inspection on the weld.

[0023] In any of the above technical solutions, further, in step S5 and step S6, the welding material is a solid welding wire that matches the parent material, the welding wire diameter is 1.2 mm, and the shielding gas is 80% Ar + 20% CO 2 .

[0024] In any of the above technical solutions, further, a welding robot is used to perform welding operations in step S5 and step S6.

[0025] In any of the above technical schemes, further, when the thickness of the steel plate is ≤80mm, the grooves of the upper plate to be welded and the lower plate to be welded form an X-shaped groove, and the angle of the X-shaped groove is 60°; when the thickness of the steel plate is >80mm, the grooves of the upper plate to be welded and the lower plate to be welded form a U-shaped groove, and the angle of the U-shaped groove is 20°-25°.

[0026] Compared with the prior art, the beneficial effects of this application are:

[0027] The welding process without root cleaning of the weld provided in the present application uses two welding guns and gas shielded welding to directly perform double-sided base welding and double-sided filling and covering. In the base welding process, the welding parameters of the rear gun are relatively large. When the assembly gap is 0-3mm, a jet transition arc is adopted, and the arc is strong and powerful. When the assembly gap is 3-4mm, a droplet transition arc is adopted, and the front gun has completed the back penetration, and the weld quality can be guaranteed. Therefore, the base welding can achieve effective penetration. In the filling and covering welding process, the arcs of the two welding guns both adopt a pulsed droplet transition form, with high welding efficiency, small spatter, and beautiful forming. The peak current of the pulsed arc can help effectively melt the interlayer oxide scale, avoiding the interlayer grinding and cleaning work, and the strong arc force can bring out impurities at the root of the base weld, thereby ensuring the quality of the base weld.

[0028] In addition, for the two upper and lower plates to be welded, the welding gun is basically horizontal, and the arc during welding directly heats the grooves of the upper and lower plates to be welded, which can ensure effective penetration of the weld, and blunt edges are set between the grooves on the left and right sides of the upper and lower plates to be welded, and the lower blunt edge is made larger. The inclination angle of the front welding gun is 8 to 10 degrees, and the end of the welding wire points to the lower blunt edge line. During base welding, the arc heat is mainly used to heat the lower blunt edge, which can avoid the weld burn-through defect when the assembly gap exceeds 2mm, and thus can effectively improve the process tolerance.

[0029] It can be seen that when the base welding can be achieved using this method, the arc heat is mainly used to heat the lower blunt edge, which can avoid the weld burn-through defect when the assembly gap exceeds 2 mm. Therefore, the process tolerance can be effectively improved, so that the root cleaning process can be effectively promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic diagram of the butt connection of two plates to be welded provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of a welding seam and a welding gun provided in an embodiment of the present application;

[0033] Figure 3 Another schematic diagram of the connection between two plates to be welded provided in an embodiment of the present application;

[0034] Figure 4Another schematic diagram of the connection between two plates to be welded is provided in an embodiment of the present application.

[0035] Reference numerals:

[0036] 1-plate to be welded, 11-upper plate to be welded, 12-lower plate to be welded, 2-groove, 3-upper blunt edge, 4-lower blunt edge, 41-edge line, 5-weld center line, 6-front welding gun, 7-rear welding gun. DETAILED DESCRIPTION

[0037] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0038] The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed, but merely represents the selected embodiments of the present application.

[0039] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0040] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Refer to the following Figures 1 to 4 A butt weld root cleaning-free welding process according to some embodiments of the present application is described.

[0043] See also Figures 1 to 3As shown, an embodiment of the present application provides a butt weld root cleaning-free welding process, comprising the following steps:

[0044] S1, completing the blanking and forming of the steel plate to form two plates 1 to be welded, and opening two-sided symmetrical grooves 2 at the welds where the two plates 1 to be welded are connected, and a blunt edge is set between the grooves 2 on both sides of the lower plate 12 to be welded;

[0045] S2, grinding and removing rust from the welding areas of the two welding plates 1 by using a grinding machine;

[0046] S3, assembling and positioning welding the two plates 1 to be welded, ensuring that the butt weld is located at the horizontal welding position;

[0047] S4, preheating the area of ​​the weld formed between the two plates 1 to be welded before welding;

[0048] S5. Perform gas shielded base welding on both sides of the weld simultaneously and in the same direction, and use arc in the form of droplet transition or jet transition during welding;

[0049] S6. Gas shielded filling and cap welding are carried out simultaneously and in the same direction on both sides of the weld, and pulse droplet transfer arc is used during welding.

[0050] According to the above description, the welding process without root cleaning of the weld provided in the present application uses two welding guns and gas shielded welding to directly perform double-sided base and double-sided filling and covering. In the base welding process, the welding parameters of the rear gun are relatively large. When the assembly gap is 0-3mm, a jet transition arc is adopted, and the arc is strong and powerful. When the assembly gap is 3-4mm, a droplet transition arc is adopted, and the front gun has completed the back penetration, and the weld quality can be guaranteed. Therefore, the base can achieve effective penetration. In the filling and covering welding process, the arcs of the two welding guns adopt a pulsed droplet transition form, with high welding efficiency, small spatter, and beautiful forming. The peak current of the pulsed arc can help to effectively melt the interlayer oxide scale, avoiding the interlayer grinding and cleaning work, and the strong arc force can bring out impurities at the root of the base weld to ensure the quality of the base weld.

[0051] And for the two upper and lower butt-jointed plates 1 to be welded, the welding gun is basically horizontal, and the arc during welding directly heats the grooves 2 of the upper and lower plates to be welded, which can ensure effective penetration of the weld, and blunt edges are set between the grooves 2 on the left and right sides of the upper and lower plates to be welded, and the lower blunt edge 4 is made larger, the inclination angle of the front welding gun 6 is 8 to 10°, and the end of the welding wire points to the edge line 41 of the lower blunt edge 4. During base welding, the arc heat is mainly used to heat the lower blunt edge 4, which can avoid the weld burn-through defect when the assembly gap exceeds 2 mm, thereby effectively improving the process tolerance.

[0052] It can be seen that when the method is used to achieve base welding, the arc heat is mainly used to heat the lower blunt edge 4, which can avoid the weld burn-through defect when the assembly gap exceeds 2 mm. Therefore, the process tolerance can be effectively improved, so that the root cleaning process can be effectively promoted.

[0053] In this embodiment, preferably, Figure 1 As shown, in step S1, the thickness of the blunt edge between the two side grooves 2 of the lower plate 12 to be welded, that is, the lower blunt edge 4, is b, and 6mm≤b≤8mm, so that the process can expand the range of the root gap tolerance c to 0-4mm. Of course, the length of the blunt edge of the two side grooves 2 of the lower plate 12 to be welded is not limited to this, and can also be selected according to actual needs.

[0054] In this embodiment, preferably, Figure 1 As shown, in step S1, the length of the blunt edge between the grooves 2 on both sides of the upper plate 11 to be welded, that is, the upper blunt edge 3, is a, and 0mm≤a≤2mm.

[0055] According to the above description, no upper blunt edge 3 is provided between the grooves 2 on both sides of the upper plate 11 to be welded, or a smaller blunt edge can be provided, mainly for effective penetration, and the specific selection is based on actual needs.

[0056] In this embodiment, preferably, Figure 1 As shown, in step S1, when 20mm≤t<80mm, flame cutting is used to open a double-sided symmetrical groove 2, and 0mm≤a≤2mm, 6mm≤b≤8mm; when t≥80mm, machining is used to open a double-sided symmetrical groove 2, and 1mm≤a≤2mm, 6mm≤b≤8mm.

[0057] According to the above description, when the thickness of the steel plate exceeds 80 mm, the filling amount of the V-groove 2 becomes larger, the welding deformation increases, and the efficiency decreases. Therefore, the length of the blunt edge of the upper plate 11 to be welded is appropriately increased to reduce the welding deformation and improve the efficiency.

[0058] Further, preferably, in step S1, when 20mm≤t<80mm, flame cutting is used to open the double-sided symmetrical groove 2; when t≥80mm, machining is used to open the double-sided symmetrical groove 2. It can be seen that when the thickness of the steel plate is small, flame cutting can be used, which is easy to operate. When the thickness of the steel plate is large, machining is more convenient, saving time and labor, and having higher work efficiency.

[0059] In this embodiment, preferably, Figure 1As shown, in step S3, the positioning weld is ground before welding to remove welding defects, and the end is ground to form a transition slope, and the error tolerance of the assembly weld is ensured to be 0-3 mm, and the root gap tolerance c is 0-4 mm. It can be seen that this process can adapt to the gap variation tolerance of 0-4 mm, and has a wider practical range.

[0060] In this embodiment, preferably, the welding equipment in step S5 and step S6 is an industrial robot, especially a trackless guided full-position crawling welding robot of Boqing Technology, and the welding power supply is CLOOS-A500FG, which has a "rapidweld" or deep melting welding mode, and the corresponding welding arc is in a jet transition form. It also has a "speed weld" or a fast pulse welding mode, and the corresponding welding arc is in a pulse droplet transition form. Of course, it is not limited to this, and can also be selected according to actual needs.

[0061] In this embodiment, preferably, Figure 2 and Figure 3 As shown, in step S5 and step S6, the front welding gun 6, i.e., the front welding gun, performs uniform penetration and back forming on the root of the groove 2, and the rear welding gun 7, i.e., the rear welding gun, performs remelting welding on the root of the penetration weld.

[0062] In this embodiment, preferably, Figures 1 to 3 As shown, in step S5, during the base welding, the front welding gun 6 does not swing, the welding wire end of the front welding gun 6 points to the edge line 41 of the lower blunt edge 4, the angle β between the front welding gun 6 and the horizontal plane is 8-10° (and preferably the angle between the welding wire of the welding gun and the horizontal plane is β), the welding current of the front welding gun 6 is 240-280A, the welding voltage of the front welding gun 6 is 27-30V, and the welding speed of the front welding gun 6 is adjusted in real time according to the root gap size of the weld to ensure that the base welding is not burned through.

[0063] According to the above description, during base welding, the power supply of the front gun uses the "rapid weld" mode, which can adjust a concentrated and stable high-intensity jet arc to achieve stable base melting depth and back penetration.

[0064] In this embodiment, preferably, Figures 1 to 3 As shown, in step S5, when the root gap tolerance c of the weld is 0-2mm, the welding speed of the front welding gun 6 is 300mm / min; when the root gap tolerance c of the weld is 2-3mm, the welding speed of the front welding gun 6 is 250-300mm / min; when the root gap tolerance c of the weld is 3-4mm, the welding speed of the front welding gun 6 is 190-250mm / min.

[0065] According to the above description, the corresponding relationship between tolerance and welding speed is given, so by selecting different welding speeds, welding with different root gap tolerances c can be adapted.

[0066] In this embodiment, preferably, Figure 2 and Figure 3 As shown, during the bottom welding process, the front welding gun 6 adjusts the welding speed in real time according to the size of the weld, and the other welding parameters remain unchanged, thereby reducing welding variables and reducing the difficulty of the operation. Of course, it is not limited to this.

[0067] In this embodiment, preferably, Figure 2 and Figure 3 As shown, in step S5, during the base welding, the rear welding gun 7 does not swing, the welding wire end of the rear welding gun 7 points to the center of the weld, that is, the weld center line 5, the welding speed of the rear welding gun 7 is consistent with the welding speed of the front welding gun 6, and the welding current and welding voltage are adjusted in real time according to the root gap size of the weld to ensure that the base weld of the rear gun is formed without sagging.

[0068] According to the above description, during base welding, the power supply of the rear gun uses the "rapid weld" mode, which can adjust a concentrated and stable high-intensity jet arc to achieve stable base melting depth and back penetration.

[0069] In this embodiment, preferably, Figures 1 to 3 As shown, in step S5, when the root gap tolerance c of the weld is 0-2mm, the welding current of the rear welding gun 7 is 300-320A, and the welding voltage of the rear welding gun 7 is 30-33V; when the root gap tolerance c of the weld is 2-3mm, the welding current of the rear welding gun 7 is 260-300A, and the welding voltage of the rear welding gun 7 is 28-31V; when the root gap tolerance c of the weld is 3-4mm, the welding current of the rear welding gun 7 is 220-260A, and the welding voltage of the rear welding gun 7 is 24-28V.

[0070] According to the above description, the corresponding relationship between the tolerance and the welding current speed and the welding voltage is given, so by selecting different welding current speeds and welding voltages, welding with different root gap tolerances c can be adapted.

[0071] In this embodiment, preferably, Figure 2 and Figure 3 As shown, during the base welding process, the rear welding gun 7 adjusts the wire feeding speed in real time according to the size of the weld, controls the welding current and welding voltage by the wire feeding speed, and keeps the other welding parameters unchanged, thereby reducing welding variables and reducing the difficulty of the operation. Of course, it is not limited to this.

[0072] In this embodiment, preferably, Figures 1 to 3As shown, in step S6, during the filling and capping welding process, both welding guns use non-swinging multi-layer and multi-pass welding, the welding current of both welding guns is 220-280A, the welding voltage of both welding guns is 24-30V, and the welding speed of both welding guns is 300-320mm / min.

[0073] According to the above description, pulse arc is used for filling and cap welding, and welding is carried out according to the above welding parameters, which can adjust a concentrated and stable high-intensity jet arc. The oxide scale breaking effect of pulse peak current and the stable swinging effect of robot welding gun can realize cleaning-free welding between layers, and the welding efficiency is high, spatter is small, and the shape is beautiful.

[0074] In this embodiment, preferably, the butt weld root cleaning-free welding process also includes the following steps: S7, performing visual inspection, internal structure inspection such as UT inspection and mechanical property inspection on the weld, especially the workpiece welded by this process is inspected to be free of defects and the mechanical property inspection is qualified.

[0075] In this embodiment, preferably, in step S5 and step S6, the welding material is a solid welding wire that matches the parent material, and the diameter of the welding wire is 1.2 mm to ensure the stability and firmness of the structure at the weld; the shielding gas is 80% Ar + 20% CO 2 The strong blowing force of gas shielded welding can remove impurities at the root of the base weld and ensure the quality of the base weld.

[0076] In this embodiment, preferably, Figure 2 As shown, in step S5, the base welding is performed simultaneously in the same direction on both sides of the weld, and the spacing L between the two welding guns, namely the front welding gun 6 and the rear welding gun 7, is 50 to 100 mm. It should be noted that: the welding starting point and the welding end point of the two welding guns are the same, and in the base welding process, the two welding guns are arranged one after the other, wherein the welding gun close to the welding end point is the aforementioned front welding gun 6, and the welding gun close to the welding starting point is the aforementioned rear welding gun 7.

[0077] According to the above description, it is necessary to maintain a preset distance between the two welding guns, so as to effectively avoid arc interference and thus ensure welding efficiency and quality.

[0078] In this embodiment, preferably, Figures 1 to 3 As shown, the two grooves 2 of the upper plate 11 to be welded and the lower plate 12 to be welded form a total V-shaped groove (see Figure 1 As shown), the angle of the V-shaped groove is 60°, that is, the single-side angle θ1 is 30.

[0079] Of course, the above structure is not limited thereto, and other structures may also be used, for example: the two grooves 2 of the upper plate 11 to be welded and the lower plate 12 to be welded form a total U-shaped groove (see Figure 4 As shown, and preferably, the bottom radius of the U-shaped groove is 10mm, of course, not limited to this, and can also be selected according to actual needs), and preferably, the angle θ2 of the U-shaped groove is 20°-25°. Of course, not limited to this, the shape and angle of the groove 2 can also be selected according to actual needs.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A butt weld root cleaning-free welding process, characterized in that: The steps include: S1. Complete the blanking and forming of the steel plate to form two plates to be welded, and open two-sided symmetrical grooves at the weld positions where the two plates to be welded are connected, and a blunt edge is set between the grooves on both sides of the lower plate to be welded; S2, grinding and removing rust from the welding areas of the two plates to be welded by a grinding machine; S3, assemble and position weld the two plates to be welded to ensure that the butt weld is located at the horizontal welding position; S4, preheating the weld area formed between the two plates to be welded before welding; S5. Perform gas shielded base welding on both sides of the weld simultaneously and in the same direction, and use arc in the form of droplet transition or jet transition during welding; S6. Gas shielded filling and cap welding are carried out simultaneously and in the same direction on both sides of the weld, and pulse droplet transfer arc is used during welding.

2. The butt weld root cleaning-free welding process according to claim 1 is characterized in that: In step S1 , the thickness of the blunt edge between the grooves on both sides of the lower plate to be welded is b, and 6 mm ≤ b ≤ 8 mm.

3. The butt weld root cleaning-free welding process according to claim 2 is characterized in that: In step S1 , the thickness of the blunt edge between the grooves on both sides of the upper plate to be welded is a, and 0 mm ≤ a ≤ 2 mm.

4. The butt weld root cleaning-free welding process according to claim 3 is characterized in that: In step S1, when 20 mm ≤ t < 80 mm, 0 mm ≤ a ≤ 2 mm, 6 mm ≤ b ≤ 8 mm; when t ≥ 80 mm, 1 mm ≤ a ≤ 2 mm, 6 mm ≤ b ≤ 8 mm.

5. The butt weld root cleaning-free welding process according to claim 1 is characterized in that: In step S3, the positioning weld is ground before welding to remove welding defects, and the end is ground to form a transition slope, and the error tolerance of the assembly weld is ensured to be 0-3 mm, and the root gap tolerance is 0-4 mm.

6. The butt weld root cleaning-free welding process according to claim 5 is characterized in that: In step S5, during the base welding, the front welding gun does not swing, the welding wire end of the front welding gun points to the lower blunt edge line, the angle between the front welding gun and the horizontal plane is 8-10°, the welding current of the front welding gun is 240-280A, the welding voltage of the front welding gun is 27-30V, and the welding speed of the front welding gun is adjusted in real time according to the root gap size of the weld to ensure that the base welding does not burn through.

7. The butt weld root cleaning-free welding process according to claim 6 is characterized in that: In step S5, when the root gap tolerance of the weld is 0-2 mm, the welding speed of the front welding gun is 300 mm / min; when the root gap tolerance of the weld is 2-3 mm, the welding speed of the front welding gun is 250-300 mm / min; when the root gap tolerance of the weld is 3-4 mm, the welding speed of the front welding gun is 190-250 mm / min; and / or During the base welding process, the front welding gun adjusts the welding speed in real time according to the size of the weld, and the other welding parameters remain unchanged.

8. The butt weld root cleaning-free welding process according to claim 5 is characterized in that: In step S5, during the base welding, the rear welding gun does not swing, the welding wire end of the rear welding gun points to the center of the weld, the welding speed of the rear welding gun is consistent with the welding speed of the front welding gun, and the welding current and welding voltage are adjusted in real time according to the root gap size of the weld to ensure that the base weld of the rear gun is formed without sagging.

9. The butt weld root cleaning-free welding process according to claim 8 is characterized in that: In step S5, when the root gap tolerance of the weld is 0-2mm, the welding current of the rear welding gun is 300-320A, and the welding voltage of the rear welding gun is 30-33V; when the root gap tolerance of the weld is 2-3mm, the welding current of the rear welding gun is 260-300A, and the welding voltage of the rear welding gun is 28-31V; when the root gap tolerance of the weld is 3-4mm, the welding current of the rear welding gun is 220-260A, and the welding voltage of the rear welding gun is 24-28V; and / or During the base welding process, the rear welding gun adjusts the wire feeding speed in real time according to the size of the weld, controls the welding current and welding voltage by the wire feeding speed, and the other welding parameters remain unchanged.

10. The butt weld root cleaning-free welding process according to claim 1, characterized in that: In step S6, during the filling and capping welding process, both welding guns use non-swinging multi-layer and multi-pass welding, the welding current of both welding guns is 220-280A, the welding voltage of both welding guns is 24-30V, and the welding speed of both welding guns is 300-320mm / min.

11. The butt weld root cleaning-free welding process according to any one of claims 1 to 10, characterized in that: The butt weld root cleaning-free welding process further comprises the following steps: S7, performing appearance inspection, internal structure inspection and mechanical property inspection on the weld; and / or In step S5 and step S6, the welding material is a solid welding wire that matches the base material, the welding wire diameter is 1.2 mm, and the shielding gas is 80% Ar + 20% CO2; and / or In step S5, the base is welded simultaneously on both sides of the weld in the same direction, and the distance between the two welding guns is 50 to 100 mm; and / or In step S5 and step S6, a welding robot is used to perform welding operations; and / or When the thickness of the steel plate is ≤80mm, the grooves of the upper plate to be welded and the lower plate to be welded form an X-shaped groove, and the angle of the X-shaped groove is 60°; when the thickness of the steel plate is >80mm, the grooves of the upper plate to be welded and the lower plate to be welded form a U-shaped groove, and the angle of the U-shaped groove is 20°-25°.

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