Robot multi-layer and multi-pass welding process

Abstract

The invention discloses a robot multi-layer and multi-pass welding technology, and relates to the technical field of welding, the technology comprises the following steps: 1, pretreating a to-be-welded workpiece A, and removing impurities on the surface of the to-be-welded workpiece A; secondly, the welding robot conducts backing welding on the two workpieces to be welded through tungsten electrode inert gas shielded welding; thirdly, multi-layer welding is carried out, each layer of welding is divided into a plurality of paths, the welding directions are alternately carried out, and a welding seam is cleaned and checked after each layer of welding is completed; and fourthly, the welding layer is subjected to heat treatment, and welding residual heat stress is eliminated. According to the method, the welding robot adopts tungsten electrode inert gas shielded welding to conduct backing welding between the two workpieces A to be welded, then multi-layer welding is conducted, the welding speed is accurately controlled through the welding robot, and full penetration of the root of a welding seam is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a robot multi-layer and multi-pass welding process. Background Art

[0002] For workpieces with thicker thickness, multi-layer and multi-pass welding can better adapt to the characteristics of the workpiece and ensure the welding effect; when performing multi-layer and multi-pass welding, the welder needs to weld on the previous weld until the entire welding process is completed.

[0003] After searching, a Chinese patent application, an invention patent with publication number CN104801838A, discloses a welding process for thick steel plates, the steel plates are Q690E steel, and the thickness of the steel plates is 30 to 60 mm; the welding process includes: preheating the steel plates before welding; using a smaller welding heat input that can control t8 / 5 to less than 30s during welding to ensure that the heat-affected zone obtains a structure dominated by fine-grained lath martensite. At the same time, a multi-layer and multi-pass welding process is used during welding. The invention uses a large amount of Q690E high-strength thick steel plate welding process in the mast crane (especially the interface parts between the whole machine structure and the hull structure). Since Q690E steel has a strong tendency to harden, the toughness of the heat-affected zone can be ensured by controlling the time t8 / 5 <30s for the molten pool to cool from 800°C to 500°C after welding. When welding Q690E steel, the preheating temperature is controlled at 150-200℃, the welding line energy is controlled at about 1.5-1.7kJ / mm, and with reasonable ultra-low hydrogen welding materials, an ideal welding joint can be obtained.

[0004] In the above application documents, the multi-layer and multi-pass welding process has simple steps, and the welding of thick steel plates is mainly achieved by controlling the welding temperature. However, there are the following shortcomings in the specific implementation: the welding speed cannot be accurately controlled, resulting in the problem of unfused root of the weld, and full penetration of the weld cannot be guaranteed; for this reason, the present invention provides a robot multi-layer and multi-pass welding process. Summary of the invention

[0005] The technical problem solved by the present invention is that the existing multi-layer and multi-pass welding process cannot accurately control the welding speed, resulting in the problem of unfused root at the weld root and failure to ensure full penetration of the weld.

[0006] The present invention can be implemented by the following technical scheme: a robot multi-layer multi-pass welding process, the process comprising the following steps:

[0007] The first step is to pre-treat the workpiece to be welded to remove impurities on the surface of the workpiece;

[0008] In the second step, the welding robot uses tungsten inert gas shielded welding to perform base welding between the two workpieces to be welded;

[0009] The third step is to carry out multi-layer welding. Each layer is divided into multiple passes, and the welding directions are carried out alternately. After each layer is welded, the weld is cleaned and inspected;

[0010] The fourth step is to heat treat the welding layer to eliminate the residual thermal stress of welding.

[0011] A further technical improvement of the present invention is that in the second step, the welding speed of the welding robot is 4-5 mm / s.

[0012] The further technical improvement of the present invention is that in the second step, the welding current of the base welding is 110-120A, the voltage is 13-15V, the shielding gas is Ne99.99%, the shielding gas flow is 8-10L / min, and the welding wire diameter is 2mm.

[0013] The further technical improvement of the present invention is that in the third step, the welding current is 250-260A, the voltage is 27-28V, the welding speed is 5-6mm / s, the shielding gas is Ne99.99%, the shielding gas flow rate is 20-25L / min, and the welding wire diameter is 1.3mm.

[0014] A further technical improvement of the present invention is that in the second step, the welding robot includes a base, a workpiece positioning mechanism is arranged on the top of the base, the workpiece positioning mechanism includes two abutment plates which penetrate through and are slidably arranged on the base, and when the two abutment plates are brought close to each other, the two workpieces to be welded are clamped, and a double-headed threaded rod is rotatably arranged at the bottom of the base, and both ends of the double-headed threaded rod respectively penetrate through the abutment plates, and the double-headed threaded rod is driven by a first servo motor.

[0015] A further technical improvement of the present invention is that a pressing plate is slidably arranged in the vertical direction on one side of the two abutting plates that are close to each other, and the pressing plate is driven by a second servo motor.

[0016] A further technical improvement of the present invention is that a support frame is fixedly connected to the top of the base, a rotating shaft is penetrated through and rotatably arranged on the top of the support frame, the rotating shaft is driven by a third servo motor, a mounting plate is fixedly connected to the bottom end of the rotating shaft, a cleaning brush and a welding gun are arranged at the bottom of the mounting plate, and after the mounting plate is rotated ninety degrees, the cleaning brush or the welding gun is located directly above the connection position of the workpiece to be welded.

[0017] A further technical improvement of the present invention is that two electric slide rails are symmetrically installed at the bottom of the mounting plate, an electric slider is installed at the bottom of each electric slide rail, and a cleaning brush and a welding gun are respectively installed at the bottom of the electric slider.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In the present invention, the welding robot uses tungsten inert gas shielded welding to perform base welding between two workpieces to be welded, and then performs multi-layer welding. The welding robot accurately controls the welding speed, effectively ensuring full penetration of the weld root.

[0020] 2. In the present invention, the second servo motor drives the pressure plate to move downward so that the bottom of the pressure plate is in contact with the top of the workpiece to be welded, thereby limiting the displacement of the two workpieces to be welded in the vertical direction. In this way, the two workpieces to be welded appear to tilt upward when they are close to each other. At the same time, when the displacement of the two workpieces to be welded in the horizontal direction is completely restricted, the second servo motor drives the pressure plate to continue to move downward, and the pressure plate is used to press the two workpieces to be welded, thereby improving the positioning stability of the two workpieces to be welded, so that the two workpieces to be welded will not loosen during welding, thereby ensuring the quality of the weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a process flow chart of multi-layer and multi-pass welding by a robot according to the present invention; Figure 2 This is a schematic diagram of the structural connection of the welding robot in the present invention; Figure 3 For the present invention Figure 2 A partial enlarged view of point B in the middle; Figure 4 It is a schematic diagram of the structural connection below the mounting plate in the present invention.

[0026] In the figure: 1. base; 2. abutment plate; 3. double-headed threaded rod; 4. pressure plate; 5. support frame; 6. rotating shaft; 7. mounting plate; 8. cleaning brush; 9. welding gun; 10. electric slide rail; 11. electric slider; 12. first servo motor; 13. second servo motor; 14. third servo motor; A. workpiece to be welded. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0028] Example 1

[0029] See also Figure 1 As shown, a robot multi-layer multi-pass welding process, a robot multi-layer multi-pass welding process, the process comprises the following steps:

[0030] The first step is to pre-treat the workpiece A to be welded to remove impurities on the surface of the workpiece A to be welded;

[0031] In the second step, the welding robot uses tungsten inert gas shielded welding to perform base welding between the two workpieces A to be welded;

[0032] The third step is to carry out multi-layer welding. Each layer is divided into multiple passes, and the welding directions are carried out alternately. After each layer is welded, the weld is cleaned and inspected;

[0033] The fourth step is to heat treat the welding layer to eliminate the residual thermal stress of welding.

[0034] Among them, in the second step, the welding speed of the welding robot is 4mm / s.

[0035] Among them, in the second step, the welding current of the base welding is 110A, the voltage is 13V, the shielding gas is Ne99.99%, the shielding gas flow rate is 8L / min, and the welding wire diameter is 2mm.

[0036] Among them, in the third step, the welding current is 250A, the voltage is 27V, the welding speed is 5mm / s, the shielding gas is Ne99.99%, the shielding gas flow rate is 20L / min, and the welding wire diameter is 1.3mm.

[0037] In the welding process of this embodiment, the welding robot uses tungsten inert gas shielded welding to perform base welding between two workpieces A to be welded, and then performs multi-layer welding. The welding robot accurately controls the welding speed, effectively ensuring full penetration of the weld root.

[0038] Example 2

[0039] A robot multi-layer multi-pass welding process, the process comprising the following steps:

[0040] The first step is to pre-treat the workpiece A to be welded to remove impurities on the surface of the workpiece A to be welded;

[0041] In the second step, the welding robot uses tungsten inert gas shielded welding to perform base welding between the two workpieces A to be welded;

[0042] The third step is to carry out multi-layer welding. Each layer is divided into multiple passes, and the welding directions are carried out alternately. After each layer is welded, the weld is cleaned and inspected;

[0043] The fourth step is to heat treat the welding layer to eliminate the residual thermal stress of welding.

[0044] Among them, in the second step, the welding speed of the welding robot is 5mm / s.

[0045] Among them, in the second step, the welding current of the base welding is 120A, the voltage is 15V, the shielding gas is Ne99.99%, the shielding gas flow rate is 10L / min, and the welding wire diameter is 2mm.

[0046] Among them, in the third step, the welding current is 260A, the voltage is 28V, the welding speed is 6mm / s, the shielding gas is Ne99.99%, the shielding gas flow rate is 25L / min, and the welding wire diameter is 1.3mm.

[0047] In the welding process of this embodiment, the welding robot uses tungsten inert gas shielded welding to perform base welding between two workpieces A to be welded, and then performs multi-layer welding. The welding robot accurately controls the welding speed, effectively ensuring full penetration of the weld root.

[0048] Example 3

[0049] See also Figure 1 As shown, in the above, the welding robot includes a base 1, and a workpiece positioning mechanism is arranged on the top of the base 1. The workpiece positioning mechanism includes two abutment plates 2 that penetrate and are slidably arranged on the base 1. When the two abutment plates 2 are close to each other, the two workpieces to be welded are clamped. A double-headed threaded rod 3 is rotatably arranged at the bottom of the base 1, and the two ends of the double-headed threaded rod 3 are respectively penetrated through the abutment plates 2, and the double-headed threaded rod 3 is driven by a first servo motor 12; when working, two workpieces A to be welded are placed on the top of the base 1, and the two sides of the two workpieces A to be welded that need to be connected are facing each other, and the PLC control system starts the first servo motor 12, so that the first servo motor 12 drives the double-headed threaded rod 3 to rotate, and the double-headed threaded rod 3 drives the two abutment plates 2 to approach each other and contact with one side of the workpiece A to be welded, and then the two abutment plates 2 push one side of the workpiece to be welded to abut against each other, so as to realize the positioning of the two workpieces A to be welded, and then the PLC control system realizes the welding of the two workpieces A to be welded through the welding gun 9.

[0050] In the above, in order to limit the displacement of the two workpieces A to be welded in the vertical direction, a pressing plate 4 is slidably provided on the side of the two abutting plates 2 that are close to each other in the vertical direction, and the pressing plate 4 is driven by the second servo motor 13; when working, the two workpieces A to be welded are placed on the top of the base 1, and the sides of the two workpieces A to be welded that need to be connected are opposite to each other, and the PLC control system starts the second servo motor 13, so that the second servo motor 13 drives the pressing plate 4 to move downward, so that the bottom of the pressing plate 4 is close to the top of the workpiece A to be welded, and the displacement of the two workpieces A to be welded in the vertical direction is limited, so that the two workpieces A to be welded appear to be tilted upward when they are close to each other, and at the same time, when the displacement of the two workpieces A to be welded in the horizontal direction is completely restricted, the second servo motor 13 drives the pressing plate 4 to continue to move downward, and the two workpieces A to be welded are pressed by the pressing plate 4, so as to improve the positioning stability of the two workpieces A to be welded, so that the two workpieces A to be welded will not be loose during welding, and the quality of the weld is guaranteed.

[0051] Furthermore, a support frame 5 is fixedly connected to the top of the base 1, and a rotating shaft 6 is penetrated and rotatably arranged on the top of the support frame 5, and the rotating shaft 6 is driven by a third servo motor 14, and a mounting plate 7 is fixedly connected to the bottom end of the rotating shaft 6, and a cleaning brush 8 and a welding gun 9 are arranged at the bottom of the mounting plate 7. After the mounting plate 7 is rotated ninety degrees, the cleaning brush 8 or the welding gun 9 is located directly above the connection position of the workpiece to be welded; two electric slide rails 10 are symmetrically installed at the bottom of the mounting plate 7, and an electric slider 11 is installed at the bottom of each electric slide rail 10, and the cleaning brush 8 and the welding gun 9 are respectively installed at the bottom of the electric slider 11; during operation, when two workpieces A to be welded are at the top of the base 1, After the parts are fully positioned, the PLC control system starts the welding gun 9, and at the same time makes the electric slider 11 slide on the electric slide rail 10, and the welding of the two workpieces A to be welded is realized through the welding gun 9, and a weld is initially formed. Before welding the second weld, the PLC control system starts the third servo motor 14, so that the third servo motor 14 drives the rotation and the mounting plate 7 to rotate, so that the electric slider 11 where the cleaning brush 8 is located and the electric slider 11 are located on the path where the first weld is located. At this time, the electric slider 11 drives the cleaning brush 8 to move, so as to clean the impurities on the surface of the first weld, and then the operation of the second weld is performed, and the operation is repeated in sequence to form a complete weld.

[0052] The working process of the welding robot is as follows: two workpieces A to be welded are placed on the top of the base 1, and the two sides of the workpieces A to be welded that need to be connected are facing each other, the PLC control system starts the second servo motor 13, so that the second servo motor 13 drives the pressure plate 4 to move downward, so that the bottom of the pressure plate 4 is close to the top of the workpiece A to be welded, and the displacement of the two workpieces A to be welded in the vertical direction is limited, so that the two workpieces A to be welded appear to be tilted upward when they are close to each other; then the PLC control system starts the first servo motor 12, so that the first servo motor 12 drives the double-headed threaded rod 3 to rotate, and the double-headed threaded rod 3 drives the two abutment plates 2 to approach each other and contact with one side of the workpiece to be welded, and then the two abutment plates 2 push one side of the workpiece to be welded to abut against each other, so as to realize the positioning of the two workpieces A to be welded, and then the PLC control system realizes the welding of the two workpieces A to be welded through the welding gun 9; when the displacement of the two workpieces A to be welded in the horizontal direction is completely restricted, the second servo motor 13 drives the pressing plate 4 to continue to move downward, and realizes the pressing of the two workpieces A to be welded through the pressing plate 4, thereby improving the positioning stability of the two workpieces A to be welded, so that the two workpieces A to be welded will not be loose during welding, thereby ensuring the quality of the weld. When the two workpieces A to be welded are completely positioned on the top of the base 1, the PLC control system starts the welding gun 9 and makes the electric slider 11 slide on the electric slide rail 10. The welding of the two workpieces A to be welded is realized through the welding gun 9 to initially form a weld. Before welding the second weld, the PLC control system starts the third servo motor 14, so that the third servo motor 14 drives the rotation and the mounting plate 7 to rotate, so that the electric slider 11 where the cleaning brush 8 is located and the electric slider 11 are located on the path where the first weld is located. At this time, the electric slider 11 drives the cleaning brush 8 to move to clean the impurities on the surface of the first weld, and then performs the operation of the second weld, and repeats in sequence to finally form a complete weld.

[0053] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 2 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A robot multi-layer multi-pass welding process, characterized in that: The process includes the following steps: The first step is to pre-treat the workpiece (A) to be welded to remove impurities on the surface of the workpiece (A); In the second step, the welding robot uses tungsten inert gas shielded welding to perform base welding between the two workpieces to be welded (A); The third step is to carry out multi-layer welding. Each layer is divided into multiple passes, and the welding directions are carried out alternately. After each layer is welded, the weld is cleaned and inspected; The fourth step is to heat treat the welding layer to eliminate the residual thermal stress of welding.

2. A robot multi-layer multi-pass welding process according to claim 1, characterized in that: In the second step, the welding speed of the welding robot is 4-5 mm / s.

3. A robot multi-layer multi-pass welding process according to claim 1, characterized in that: In the second step, the welding current of the base welding is 110-120A, the voltage is 13-15V, the shielding gas is Ne99.99%, the shielding gas flow rate is 8-10L / min, and the welding wire diameter is 2mm.

4. A robot multi-layer multi-pass welding process according to claim 1, characterized in that: In the third step, the welding current is 250-260A, the voltage is 27-28V, the welding speed is 5-6mm / s, the shielding gas is Ne99.99%, the shielding gas flow rate is 20-25L / min, and the welding wire diameter is 1.3mm.

5. A robot multi-layer multi-pass welding process according to claim 1, characterized in that: In the second step, the welding robot comprises a base (1), the top of the base (1) is provided with a workpiece positioning mechanism, the workpiece positioning mechanism comprises two abutment plates (2) penetrating and slidably arranged on the base (1), and when the two abutment plates (2) are brought close to each other, two workpieces (A) to be welded are clamped, and a double-headed threaded rod (3) is rotatably arranged at the bottom of the base (1), the two ends of the double-headed threaded rod (3) respectively penetrate the abutment plates (2), and the double-headed threaded rod (3) is driven by a first servo motor (12).

6. A robot multi-layer multi-pass welding process according to claim 5, characterized in that: A pressing plate (4) is slidably arranged in the vertical direction on one side of the two abutting plates (2) that are close to each other, and the pressing plate (4) is driven by a second servo motor (13).

7. A robot multi-layer multi-pass welding process according to claim 5, characterized in that: The top of the base (1) is fixedly connected to a support frame (5), the top of the support frame (5) is penetrated by a rotating shaft (6) which is rotatably arranged, the rotating shaft (6) is driven by a third servo motor (14), the bottom end of the rotating shaft (6) is fixedly connected to a mounting plate (7), the bottom of the mounting plate (7) is provided with a cleaning brush (8) and a welding gun (9), and after the mounting plate (7) is rotated ninety degrees, the cleaning brush (8) or the welding gun (9) is located directly above the connection position of the workpiece to be welded.

8. A robot multi-layer multi-pass welding process according to claim 7, characterized in that: Two electric slide rails (10) are symmetrically mounted at the bottom of the mounting plate (7), an electric slider (11) is mounted at the bottom of each electric slide rail (10), and a cleaning brush (8) and a welding gun (9) are respectively mounted at the bottom of the electric slider (11).

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