Full penetration welding method for butt joint of thick plate

Abstract

The invention relates to the technical field of welding, in particular to a thick plate butt joint full penetration welding method, which comprises the following process steps of: 1, butting a workpiece I and a workpiece II with the thickness of more than or equal to 100mm together, and forming a narrow gap welding groove with the groove angle of less than or equal to 5 degrees at the butting part; (2) spot welding fixing is conducted on the first workpiece and the second workpiece in the step (1) at the non-interference narrow gap welding groove through a temporary fixing horse plate; 3, backing welding is conducted on the back side of the narrow gap welding groove in a manual welding mode; fourthly, a welding robot is adopted for conducting automatic welding on the narrow-gap welding groove in the third step; the welding gun thickness of the welding robot is smaller than or equal to 6 mm. According to the method, the thick plate welding groove is controlled to adapt to the working characteristics of the welding robot, so that the welding robot reliably adapts to the full penetration welding operation of the thick plate, and the technical requirements of a high-performance welding type cable saddle can be reliably met.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a full penetration welding method for thick plate butt joints. Background Art

[0002] In the cable saddle structure of a suspension bridge, a welded cable saddle structure is usually used to improve the stress performance and ensure the compactness of the structure. That is, the saddle body of the cable saddle is welded from multiple steel plates.

[0003] With the continuous increase in the span of suspension bridges, higher technical requirements are placed on the bearing performance of the cable saddles, which requires that the steel plates constituting the welded cable saddles adopt a larger cross-sectional thickness, usually requiring a thickness ≥100mm. In other words, the welded cable saddle has a technical requirement for welding steel plates with a thickness of ≥100mm, and it must be achieved by full penetration welding.

[0004] Since the saddle body of the welded cable saddle is welded from multiple steel plates, there are many welds, and the high technical requirements for full penetration welding and first-level flaw detection make the welding workload huge. At present, for the welding of steel plates with a thickness of ≥100mm, in order to adapt to the technical characteristics of thick plate welding, large groove angle, large amount of deposited metal, and long welding time, manual welding is used. Due to the low efficiency and unstable welding quality of manual welding, it is difficult to meet the technical requirements of high-performance welded cable saddles.

[0005] In recent years, with the development of science and technology, welding robots have been widely used in workpiece welding. However, for thick plate welding, due to its large groove angle and large amount of deposited metal, the visual system accuracy of the welding robot is not enough to support the thermal deformation of the thick plate welding process, and it cannot effectively identify and correct deviations, making it difficult for welding robots to be reliably used in thick plate welding environments. Summary of the invention

[0006] The technical purpose of the present invention is to provide a full penetration welding method for thick plate butt joints that effectively reduces the amount of thick plate welding, controls heat input, and enables welding robots to reliably adapt to thick plate welding, in view of the particularity of the above-mentioned thick plate welding and the high technical requirements for welding quality, as well as the shortcomings of the prior art.

[0007] The technical purpose of the present invention is achieved by the following technical solution: a full penetration welding method for thick plate butt joints, the welding method comprising the following process steps:

[0008] Step 1. Butt workpiece 1 and workpiece 2 with a thickness of ≥100 mm together, and form a narrow gap welding groove with a groove angle of ≤5° at the butt joint;

[0009] Step 2. Use a temporary fixing plate to spot weld workpiece 1 and workpiece 2 in step 1 without interfering with the narrow gap welding groove;

[0010] Step 3. Perform root welding on the opposite side of the narrow gap welding groove by manual welding;

[0011] Step 4. Use a welding robot to automatically weld the narrow gap welding groove of step 3;

[0012] The welding robot's welding gun thickness is ≤6mm.

[0013] Furthermore, in step 4, the automatic welding process of the narrow gap welding groove by the welding robot is:

[0014] S1. Before the first welding, the welding robot scans the surface width of the narrow gap welding groove with a visual system, and identifies the narrow gap welding groove according to the input groove surface angle;

[0015] S2. The path planning system of the welding robot determines the vertical coordinates of the starting point of the contact tip in the narrow gap welding groove based on the surface width of the narrow gap welding groove extracted by the visual system and the angle of the groove surface, wherein the vertical coordinates of the starting point correspond to the Y axis in the depth direction and to the X axis in the width direction;

[0016] The path planning system determines the running track of the contact nozzle in the narrow gap welding groove according to the longitudinal length of the narrow gap welding groove extracted by the visual system, corresponding to the Z axis;

[0017] The path planning system determines the Y-axis adjustment path of the contact tip from inside to outside between two adjacent welding layers in the narrow gap welding groove based on the single-layer filling amount;

[0018] The path planning system determines the relative value of the left and right swing of the welding wire in the narrow gap welding groove in the width direction based on the gradual change of the width of the narrow gap welding groove from the bottom of the groove to the top of the groove, which increases monotonically from 0 swing at the bottom of the groove to 1 swing at the top of the groove;

[0019] Generate welding paths;

[0020] S3. The central controller of the welding robot outputs welding instructions to the robot arm and the end effector based on the generated welding path and input welding parameters to complete the full penetration welding of the narrow gap welding groove.

[0021] Further, in step S2, the path planning system determines the vertical coordinates of the starting point of the contact nozzle in the narrow gap welding groove to satisfy the following relationship:

[0022] y=-[(tan(90-α)×(x / 2-R)-12)];

[0023] Where y is the distance from the conductive tip extending into the narrow gap welding groove to the bottom of the groove;

[0024] α is the groove face angle of the narrow gap welding groove;

[0025] x is the surface width of the narrow gap welding groove;

[0026] R is the arc radius of the bottom of the narrow gap welding groove;

[0027] 12 is a constant.

[0028] Furthermore, in step S3, the welding parameters input are:

[0029] Welding current 270~290A;

[0030] Welding voltage 28~33V;

[0031] Welding speed 3-4 mm / s;

[0032] The welding gun tilt angle is 0~5°.

[0033] Furthermore, the shielding gas used by the welding robot for automatic welding is 80% Ar + 20% CO 2 ;

[0034] The welding wire used is GML-W60 and the diameter of the welding wire is Φ1.2mm.

[0035] Furthermore, the workpiece 1 and the workpiece 2 are components of a welded saddle of a suspension bridge.

[0036] Furthermore, the workpiece 1 and the workpiece 2 are steel plates for forming the saddle body of the welded saddle of the suspension bridge, and the steel plates are Q345R steel plates; the thickness of the workpiece 1 and the workpiece 2 are 150 mm respectively;

[0037] The groove angle of the narrow gap welding groove at the joint between the workpiece 1 and the workpiece 2 is 4°, and the arc radius of the groove bottom is 3.5 mm.

[0038] Furthermore, during the automatic welding process, the welding robot interrupts welding after welding three layers and uses an air shovel to remove burrs and spatters on the weld surface.

[0039] Furthermore, after the automatic welding is completed, the welding robot cools and performs flaw detection on the weld.

[0040] Furthermore, the flaw detection process is to perform the first flaw detection after the weld has finished cooling;

[0041] The second flaw detection is carried out 24 hours after the weld has finished cooling;

[0042] The above-mentioned flaw detection is an ultrasonic flaw detection method, which is carried out in accordance with GB / T11345-2023 Class B detection, and the test results meet the technical requirements of GB / T29712-2023 Class 2.

[0043] The beneficial technical effect of the present invention is: in view of the particularity of the above-mentioned thick plate welding and the high technical requirements for welding quality, by controlling the thick plate welding groove, a narrow gap welding groove of a specific structure is formed, which effectively reduces the thick plate welding amount and controls the heat input, so that the thermal deformation of the thick plate welding process under the specific narrow gap welding groove can reach the recognition accuracy of the visual system of the welding robot, so that the control of the thick plate welding groove is adapted to the working characteristics of the welding robot, so that the welding robot can reliably adapt to the full penetration welding operation of the thick plate, which is particularly prominent under the support of the welding robot for the specific automatic welding process of the narrow gap welding groove, and can reliably meet the technical requirements of high-performance welded saddles. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of a narrow gap welding groove for thick plate welding according to the present invention.

[0045] The meaning of the codes in the figure: 1—workpiece one; 2—workpiece two; 3—narrow gap welding groove; 4—base welding layer; α—groove surface angle; β—groove angle. DETAILED DESCRIPTION

[0046] The present invention relates to the field of welding technology, and more specifically to a method for full penetration welding of thick plate butt joints. The main technical solution of the present invention is specifically described below in conjunction with a plurality of embodiments. Figure 1 The technical solution of the present invention is explained clearly and in detail.

[0047] It should be noted that the drawings of the present invention are schematic, and unnecessary details have been simplified to clarify the technical purpose of the present invention, so as to avoid blurring the technical solution of the present invention that contributes to the prior art. In addition, the expressions "approximately", "substantially" and the like regarding quantity or matching relationship in the following text mean that reasonable assembly errors and processing errors in the industry are allowed to exist, and do not literally express absolute quantities or matching relationships.

[0048] Example 1

[0049] The welding object of the present invention is the saddle body of the welded saddle used in the suspension bridge. The saddle body is a full penetration welded structure of multiple Q345R steel plates. The thickness of each steel plate is about 150 mm. It is necessary to weld two butt-jointed Q345R steel plates with a thickness of about 150 mm respectively together by full penetration welding.

[0050] likeFigure 1 As shown, the two butted steel plates form workpiece 1 and workpiece 2, and the butt joint between workpiece 1 and workpiece 2 is the welding target area.

[0051] by Figure 1 The thick plate butt joint shown in the figure is taken as the object, and the welding method of the present invention comprises the following process steps:

[0052] Step 1. Cut workpiece 1 and workpiece 2, each with a thickness of about 150 mm, according to the design size, and use mechanical processing to process the butt edges of the two to form a narrow gap welding groove 3 (including processing of the groove surface angle α, etc.) that can form the following design requirements;

[0053] The processed workpiece 1 and workpiece 2 are butted together, and the butt assembly dimensions are measured to ensure that they meet the technical requirements of the assembly design, so that the workpiece 1 and workpiece 2 form a groove angle β of about 4° (note that the groove angle β refers to the angle formed between the groove surfaces on both sides of the welding groove, which is distinguished from the groove surface angle α on one side of the welding groove; the groove surface angle α refers to the angle between the groove surface on one side of the welding groove and the mid-plane of the welding groove width, the same below; when the groove angle β is about 4°, the groove surface angle α on one side of the welding groove is about 4° / 2=2°), and a narrow gap welding groove 3 with a groove bottom arc radius of about 3.5 mm;

[0054] Step 2. Use a temporary fixing plate to fix the workpiece 1 and workpiece 2 of step 1 on the side opposite to the narrow gap welding groove 3 (i.e. Figure 1 The bottom side shown in the figure) is spot welded to fix it, so that the spot welding fixing structure of the temporary fixing horse plate does not interfere with the working area of ​​the narrow gap welding groove 3;

[0055] Step 3. Use manual welding to weld the opposite side of the groove 3 at the narrow gap (i.e. Figure 1 A bottom welding is performed on the bottom side of the workpiece 1 to form a bottom welding layer 4 to relatively fix the joint between the workpiece 1 and the workpiece 2 and seal it from the bottom side;

[0056] Step 4. Use a welding robot to automatically weld the narrow gap welding groove 3 of step 3;

[0057] The welding gun of the welding robot used is about 5mm thick;

[0058] The shielding gas used by the welding robot for automatic welding is 80% Ar + 20% CO 2 ;

[0059] The welding wire used by the welding robot for automatic welding is GML-W60, and the diameter of the welding wire is Φ1.2mm.

[0060] The automatic welding process of the welding robot for the narrow gap welding groove 3 follows the following technical means:

[0061] S1. Before the first welding, the welding robot scans the narrow gap welding groove 3 with a visual system, extracts the surface width of the narrow gap welding groove 3 - that is, the groove width, and identifies the narrow gap welding groove form according to the groove surface angle α, steel plate thickness, etc. pre-input in the program;

[0062] S2. The path planning system of the welding robot determines the vertical coordinates of the starting point of the conductive tip in the narrow gap welding groove 3 based on the groove width of the narrow gap welding groove 3 extracted by the visual system and the groove surface angle α, wherein the vertical coordinates of the starting point correspond to the Y axis in the depth direction and to the X axis in the width direction;

[0063] The path planning system determines the running track of the conductive tip in the narrow gap welding groove 3 according to the longitudinal length of the narrow gap welding groove 3 extracted by the visual system, corresponding to the Z axis;

[0064] The path planning system determines the Y-axis adjustment path of the contact tip from inside to outside between two adjacent welding layers in the narrow gap welding groove 3 based on the single-layer filling amount;

[0065] The path planning system uses the width gradient of the narrow gap welding groove 3 from the bottom to the top of the groove as a reference to determine the relative value of the left and right swing of the welding wire in the width direction of the narrow gap welding groove 3, which increases monotonically from 0 swing at the bottom of the groove to 1 swing at the top of the groove. Usually, the maximum swing at the top of the groove is 3mm.

[0066] Generate welding paths sequentially;

[0067] S3. The central controller of the welding robot outputs welding instructions to the robot arm and the end effector based on the generated welding path and input welding parameters to complete the full penetration welding of the narrow gap welding groove 3.

[0068] The path planning system determines the vertical coordinates of the starting point of the contact tip in the narrow gap welding groove, which satisfies the following relationship:

[0069] y=-[(tan(90-α)×(x / 2-R)-12)];

[0070] Where y is the distance from the conductive tip extending into the narrow gap welding groove to the bottom of the groove;

[0071] α is the groove face angle of the narrow gap welding groove;

[0072] x is the surface width of the narrow gap welding groove;

[0073] R is the arc radius of the bottom of the narrow gap welding groove;

[0074] 12 is a constant.

[0075] The welding parameters inputted above are: welding current 280A; welding voltage 30V; welding speed 3mm / s; welding gun tilt angle in the range of 0 to 5°.

[0076] During the automatic welding process, the welding robot interrupts welding after welding three layers, and uses an air shovel to remove burrs and spatters on the weld surface to achieve slag removal.

[0077] With the above welding method, after the welding robot completes full penetration welding of the thick plate butt joint with a thickness of about 150mm, the weld is cooled and inspected. Among them, the inspection is the first inspection after the weld is cooled; the second inspection is carried out 24 hours after the weld is cooled. The inspection is ultrasonic inspection, according to GB / T11345-2023 B-level inspection, and the inspection results meet the technical requirements of GB / T29712-20232-level.

[0078] Example 2

[0079] The welding object of the present invention is the saddle body of the welded saddle used in the suspension bridge. The saddle body is a full penetration welded structure of multiple Q345R steel plates. The thickness of each steel plate is about 130 mm. It is necessary to weld two butt-jointed Q345R steel plates with a thickness of about 130 mm respectively together by full penetration welding.

[0080] like Figure 1 As shown, the two butted steel plates form workpiece 1 and workpiece 2, and the butt joint between workpiece 1 and workpiece 2 is the welding target area.

[0081] by Figure 1 The thick plate butt joint shown in the figure is taken as the object, and the welding method of the present invention comprises the following process steps:

[0082] Step 1. Cut workpiece 1 and workpiece 2, each with a thickness of about 130 mm, according to the design size, and use mechanical processing to process the butt edges of the two to form a narrow gap welding groove 3 (including processing of the groove surface angle α, etc.) that can form the following design requirements;

[0083] The processed workpiece 1 and workpiece 2 are butted together, and the butt assembly dimensions are measured to ensure that they meet the technical requirements of the assembly design, so that the workpiece 1 and workpiece 2 form a narrow gap welding groove 3 with a groove angle β of about 5° (the groove surface angle α on one side is about 2.5°) and a groove bottom arc radius of about 3.5 mm at the butt joint;

[0084] Step 2. Use a temporary fixing plate to fix the workpiece 1 and workpiece 2 of step 1 on the side opposite to the narrow gap welding groove 3 (i.e. Figure 1 The bottom side shown in the figure) is spot welded to fix it, so that the spot welding fixing structure of the temporary fixing horse plate does not interfere with the working area of ​​the narrow gap welding groove 3;

[0085] Step 3. Use manual welding to weld the opposite side of the groove 3 at the narrow gap (i.e. Figure 1 A bottom welding is performed on the bottom side of the workpiece 1 to form a bottom welding layer 4 to relatively fix the joint between the workpiece 1 and the workpiece 2 and seal it from the bottom side;

[0086] Step 4. Use a welding robot to automatically weld the narrow gap welding groove 3 of step 3;

[0087] The welding gun of the welding robot used is about 5mm thick;

[0088] The shielding gas used by the welding robot for automatic welding is 80% Ar + 20% CO 2 ;

[0089] The welding wire used by the welding robot for automatic welding is GML-W60, and the diameter of the welding wire is Φ1.2mm.

[0090] The automatic welding process of the welding robot for the narrow gap welding groove 3 follows the following technical means:

[0091] S1. Before the first welding, the welding robot scans the narrow gap welding groove 3 with a visual system, extracts the surface width of the narrow gap welding groove 3 - that is, the groove width, and identifies the narrow gap welding groove form according to the groove surface angle α, steel plate thickness, etc. pre-input in the program;

[0092] S2. The path planning system of the welding robot determines the vertical coordinates of the starting point of the conductive tip in the narrow gap welding groove 3 based on the surface width of the narrow gap welding groove 3 extracted by the visual system and the groove surface angle α, wherein the vertical coordinates of the starting point correspond to the Y axis in the depth direction and to the X axis in the width direction;

[0093] The path planning system determines the running track of the conductive tip in the narrow gap welding groove 3 according to the longitudinal length of the narrow gap welding groove 3 extracted by the visual system, corresponding to the Z axis;

[0094] The path planning system determines the Y-axis adjustment path of the contact tip from inside to outside between two adjacent welding layers in the narrow gap welding groove 3 based on the single-layer filling amount;

[0095] The path planning system determines the relative value of the left and right swing of the welding wire in the narrow gap welding groove 3 in the width direction based on the gradual change of the width from the bottom of the groove to the top of the groove, which increases monotonically from 0 swing at the bottom of the groove to 1 swing at the top of the groove. Usually, the maximum swing at the top of the groove is 5mm.

[0096] Generate welding paths sequentially;

[0097] S3. The central controller of the welding robot outputs welding instructions to the robot arm and the end effector based on the generated welding path and input welding parameters to complete the full penetration welding of the narrow gap welding groove 3.

[0098] The path planning system determines the vertical coordinates of the starting point of the contact tip in the narrow gap welding groove, which satisfies the following relationship:

[0099] y=-[(tan(90-α)×(x / 2-R)-12)];

[0100] Where y is the distance from the conductive tip extending into the narrow gap welding groove to the bottom of the groove;

[0101] α is the groove face angle of the narrow gap welding groove;

[0102] x is the surface width of the narrow gap welding groove;

[0103] R is the arc radius of the bottom of the narrow gap welding groove;

[0104] 12 is a constant.

[0105] The welding parameters inputted above are: welding current 270A; welding voltage 28V; welding speed 3mm / s; welding gun tilt angle in the range of 0 to 5°.

[0106] During the automatic welding process, the welding robot interrupts welding after welding three layers, and uses an air shovel to remove burrs and spatters on the weld surface to achieve slag removal.

[0107] With the above welding method, the welding robot completes full penetration welding of the thick plate butt joint with a thickness of about 130 mm, and then cools and inspects the weld. Among them, the first inspection is performed after the weld is cooled; the second inspection is performed 24 hours after the weld is cooled. The inspection is ultrasonic inspection, and the inspection is carried out according to GB / T11345-2023 B-level inspection. The inspection results meet the technical requirements of GB / T29712-20232-level.

[0108] Example 3

[0109] The welding object of the present invention is the saddle body of a welded saddle used in a suspension bridge. The saddle body is a full penetration welded structure of multiple Q345R steel plates, each of which has a thickness of approximately 100 mm. It is necessary to weld two butt-jointed Q345R steel plates, each of which has a thickness of approximately 100 mm, together by full penetration welding.

[0110] like Figure 1 As shown, the two butted steel plates form workpiece 1 and workpiece 2, and the butt joint between workpiece 1 and workpiece 2 is the welding target area.

[0111] by Figure 1 The thick plate butt joint shown in the figure is taken as the object, and the welding method of the present invention comprises the following process steps:

[0112] Step 1. Cut workpiece 1 and workpiece 2, each with a thickness of about 100 mm, according to the design size, and use mechanical processing to process the butt edges of the two to form a narrow gap welding groove 3 (including processing of the groove surface angle α, etc.) that can form the following design requirements;

[0113] The processed workpiece 1 and workpiece 2 are butted together, and the butt assembly dimensions are measured to ensure that they meet the technical requirements of the assembly design, so that the workpiece 1 and workpiece 2 form a narrow gap welding groove 3 with a groove angle β of about 3° (a groove surface angle α on one side is about 1.5°) and a groove bottom arc radius of about 3.5 mm at the butt joint;

[0114] Step 2. Use a temporary fixing plate to fix the workpiece 1 and workpiece 2 of step 1 on the side opposite to the narrow gap welding groove 3 (i.e. Figure 1 The bottom side shown in the figure) is spot welded to fix it, so that the spot welding fixing structure of the temporary fixing horse plate does not interfere with the working area of ​​the narrow gap welding groove 3;

[0115] Step 3. Use manual welding to weld the opposite side of the groove 3 at the narrow gap (i.e. Figure 1 A bottom welding is performed on the bottom side of the workpiece 1 to form a bottom welding layer 4 to relatively fix the joint between the workpiece 1 and the workpiece 2 and seal it from the bottom side;

[0116] Step 4. Use a welding robot to automatically weld the narrow gap welding groove 3 of step 3;

[0117] The welding gun of the welding robot used is about 5mm thick;

[0118] The shielding gas used by the welding robot for automatic welding is 80% Ar + 20% CO 2 ;

[0119] The welding wire used by the welding robot for automatic welding is GML-W60, and the diameter of the welding wire is Φ1.2mm.

[0120] The automatic welding process of the welding robot for the narrow gap welding groove 3 follows the following technical means:

[0121] S1. Before the first welding, the welding robot scans the narrow gap welding groove 3 with a visual system, extracts the surface width of the narrow gap welding groove 3 - that is, the groove width, and identifies the narrow gap welding groove form according to the groove surface angle α, steel plate thickness, etc. pre-input in the program;

[0122] S2. The path planning system of the welding robot determines the vertical coordinates of the starting point of the conductive tip in the narrow gap welding groove 3 based on the surface width of the narrow gap welding groove 3 extracted by the visual system and the groove surface angle α, wherein the vertical coordinates of the starting point correspond to the Y axis in the depth direction and to the X axis in the width direction;

[0123] The path planning system determines the running track of the conductive tip in the narrow gap welding groove 3 according to the longitudinal length of the narrow gap welding groove 3 extracted by the visual system, corresponding to the Z axis;

[0124] The path planning system determines the Y-axis adjustment path of the contact tip from inside to outside between two adjacent welding layers in the narrow gap welding groove 3 based on the single-layer filling amount;

[0125] The path planning system determines the relative value of the left and right swing of the welding wire in the narrow gap welding groove 3 in the width direction based on the gradual change of the width from the bottom of the groove to the top of the groove, which increases monotonically from 0 swing at the bottom of the groove to 1 swing at the top of the groove. Usually, the maximum swing at the top of the groove is 4mm.

[0126] Generate welding paths sequentially;

[0127] S3. The central controller of the welding robot outputs welding instructions to the robot arm and the end effector based on the generated welding path and input welding parameters to complete the full penetration welding of the narrow gap welding groove 3.

[0128] The path planning system determines the vertical coordinates of the starting point of the contact tip in the narrow gap welding groove, which satisfies the following relationship:

[0129] y=-[(tan(90-α)×(x / 2-R)-12)];

[0130] Where y is the distance from the conductive tip extending into the narrow gap welding groove to the bottom of the groove;

[0131] α is the groove face angle of the narrow gap welding groove;

[0132] x is the surface width of the narrow gap welding groove;

[0133] R is the arc radius of the bottom of the narrow gap welding groove;

[0134] 12 is a constant.

[0135] The welding parameters inputted above are: welding current 290A; welding voltage 33V; welding speed 4mm / s; welding gun tilt angle in the range of 0 to 5°.

[0136] During the automatic welding process, the welding robot interrupts welding after welding three layers, and uses an air shovel to remove burrs and spatters on the weld surface to achieve slag removal.

[0137] With the above welding method, the welding robot completes full penetration welding of the thick plate butt joint with a thickness of about 130 mm, and then cools and inspects the weld. Among them, the first inspection is performed after the weld is cooled; the second inspection is performed 24 hours after the weld is cooled. The inspection is ultrasonic inspection, and the inspection is carried out according to GB / T11345-2023 B-level inspection. The inspection results meet the technical requirements of GB / T29712-20232-level.

[0138] The above embodiments are only used to illustrate the present invention, but not to limit it.

[0139] Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the above embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents, for example, they may be used for full penetration welding of thick plates of other workpieces, etc. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the present invention.

Claims

1. A full penetration welding method for thick plate butt joints, characterized in that: The welding method comprises the following process steps: Step 1. Butt workpiece 1 and workpiece 2 with a thickness of ≥100 mm together, and form a narrow gap welding groove with a groove angle of ≤5° at the butt joint; Step 2. Use a temporary fixing plate to spot weld workpiece 1 and workpiece 2 in step 1 without interfering with the narrow gap welding groove; Step 3. Perform root welding on the opposite side of the narrow gap welding groove by manual welding; Step 4. Use a welding robot to automatically weld the narrow gap welding groove of step 3; The welding robot's welding gun thickness is ≤6mm.

2. The method for full penetration welding of thick plate butt joints according to claim 1 is characterized in that: In step 4, the automatic welding process of the narrow gap welding groove by the welding robot is: S1. Before the first welding, the welding robot scans the surface width of the narrow gap welding groove with a visual system, and identifies the narrow gap welding groove according to the input groove surface angle; S2. The path planning system of the welding robot determines the vertical coordinates of the starting point of the contact tip in the narrow gap welding groove based on the surface width of the narrow gap welding groove extracted by the visual system and the angle of the groove surface, wherein the vertical coordinates of the starting point correspond to the Y axis in the depth direction and to the X axis in the width direction; The path planning system determines the running track of the contact nozzle in the narrow gap welding groove according to the longitudinal length of the narrow gap welding groove extracted by the visual system, corresponding to the Z axis; The path planning system determines the Y-axis adjustment path of the contact tip from inside to outside between two adjacent welding layers in the narrow gap welding groove based on the single-layer filling amount; The path planning system determines the relative value of the left and right swing of the welding wire in the narrow gap welding groove in the width direction based on the gradual change of the width of the narrow gap welding groove from the bottom of the groove to the top of the groove, which increases monotonically from 0 swing at the bottom of the groove to 1 swing at the top of the groove; Generate welding paths; S3. The central controller of the welding robot outputs welding instructions to the robot arm and the end effector based on the generated welding path and input welding parameters to complete the full penetration welding of the narrow gap welding groove.

3. The method for full penetration welding of thick plate butt joints according to claim 2 is characterized in that: In step S2, the path planning system determines the vertical coordinates of the starting point of the contact nozzle in the narrow gap welding groove, which satisfies the following relationship: y=-[(tan(90-α)×(x / 2-R)-12)]; Where y is the distance from the conductive tip extending into the narrow gap welding groove to the bottom of the groove; α is the groove face angle of the narrow gap welding groove; x is the surface width of the narrow gap welding groove; R is the arc radius of the bottom of the narrow gap welding groove; 12 is a constant.

4. The method for full penetration welding of thick plate butt joints according to claim 2 is characterized in that: In step S3, the welding parameters input are: Welding current 270~290A; Welding voltage 28~33V; Welding speed 3-4 mm / s; The welding gun tilt angle is 0~5°.

5. The method for full penetration welding of thick plate butt joints according to claim 1 or 2, characterized in that: The shielding gas used by the welding robot for automatic welding is 80% Ar + 20% CO2; The welding wire used is GML-W60 and the diameter of the welding wire is Φ1.2mm.

6. The method for full penetration welding of thick plate butt joints according to claim 1, characterized in that: The workpiece 1 and the workpiece 2 are components of the welded saddle of a suspension bridge.

7. The method for full penetration welding of thick plate butt joints according to claim 6, characterized in that: The workpiece 1 and the workpiece 2 are steel plates for the saddle body of the welded saddle of the suspension bridge, and the steel plates are Q345R steel plates; the thickness of the workpiece 1 and the workpiece 2 are 150 mm respectively; The groove angle of the narrow gap welding groove at the joint between the workpiece 1 and the workpiece 2 is 4°, and the arc radius of the groove bottom is 3.5 mm.

8. The method for full penetration welding of thick plate butt joints according to claim 1, characterized in that: During the automatic welding process, the welding robot interrupts welding after welding three layers, and uses an air shovel to remove burrs and spatters on the weld surface.

9. The method for full penetration welding of thick plate butt joints according to claim 1, characterized in that: After the automatic welding is completely completed, the welding robot cools and performs flaw detection on the weld.

10. The method for full penetration welding of thick plate butt joints according to claim 9, characterized in that: The flaw detection process is to perform the first flaw detection after the weld has finished cooling; The second flaw detection is carried out 24 hours after the weld has finished cooling; The above-mentioned flaw detection is an ultrasonic flaw detection method, which is tested in accordance with GB / T11345-2023 B, and the test results meet the technical requirements of GB / T29712-2023 Level 2.

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