Automatic welding method for pressure steel pipe

Abstract

The invention discloses an automatic pressure steel pipe welding method, and relates to the technical field of steel pipe welding. The method mainly comprises the steps that S1, the section of a weld joint is evenly divided into four sections in the clockwise direction, and the starting points of the four sections are a, b, c and d respectively; s2, the welding robot A starts arcing from the point c and the welding robot B starts arcing from the point d at the same time, welding is stopped until the welding robot A reaches the point b, and welding is stopped after the welding robot B reaches the point a; s3, the welding robot B automatically returns to a point c; and S4, the welding robot A starts arcing from the point b and the welding robot B starts arcing from the point c at the same time, welding is stopped until the welding robot A reaches the point a, and welding is stopped after the welding robot B reaches the point d. According to the automatic welding method for the pressure steel pipe, shrinkage stress generated during synchronous welding of the two sides of the steel pipe can be mutually balanced, and therefore warping or twisting caused by stress concentration is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of steel pipe welding, and particularly relates to an automatic welding method for penstocks. Background Art

[0002] Welding technology plays an extremely important role in penstock projects. As one of the main methods for connecting pipeline components, welding technology is directly related to the safety, stability, and reliability of penstock projects. Specifically: through effective welding technology, firm connections of various pipeline components can be achieved, ensuring the overall structural stability of the pipeline system, thereby effectively preventing safety accidents caused by loosening or falling off; at the same time, reasonable welding processes and quality control can ensure the sealing and pressure resistance of pipeline welds, avoiding serious consequences such as leakage or bursting of the pipeline system.

[0003] Currently, in order to improve the welding efficiency of large-diameter penstocks and meet the welding requirements for welding from bottom to top, two pipeline welding robots are mostly used to simultaneously start arcing from the bottom of the steel pipe joint and synchronously weld upward to the top of the steel pipe joint to achieve the welding of large-diameter penstocks.

[0004] However, since the two welding sections are left-right symmetric, the entire welding heat-affected zone is a process of gradually transferring from bottom to top, resulting in unbalanced shrinkage stress and local stress concentration during welding, and thus causing relatively large structural deformation. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic welding method for penstocks, which can balance the shrinkage stresses generated during synchronous welding on both sides of the steel pipe, thereby reducing warping or twisting caused by stress concentration.

[0006] The technical solution for the present invention to solve the above technical problems is: an automatic welding method for penstocks, comprising the following steps: S1. Divide the weld cross-section of two penstocks into four sections in the clockwise direction, and the starting points of each section are a, b, c, and d respectively; S2. Welding robot A starts arcing from point c, and welding robot B starts arcing from point d simultaneously, and starts welding from bottom to top synchronously with preset parameters until welding robot A stops welding after reaching point b, and welding robot B stops welding after reaching point a; S3. Welding robot B performs automatic retraction until welding robot B stops retracting after reaching point c; S4. Welding robot A starts arcing from point b, and welding robot B starts arcing from point c simultaneously, and starts welding from bottom to top synchronously with preset parameters until welding robot A stops welding after reaching point a, and welding robot B stops welding after reaching point d; S5. The A welding robot and the B welding robot simultaneously perform automatic backward movement until the A welding robot reaches point b and the B welding robot reaches point c, and then the backward movement stops. S6. The A welding robot performs automatic backward movement until it reaches point c and then stops. Meanwhile, the B welding robot performs automatic forward movement until it reaches point d and then stops. S7. Repeat steps S2 - S6 until the welding of two penstocks is completed.

[0007] As a further improvement of the present invention, positioning devices are installed on the penstocks beside the four starting points a, b, c, and d. Both the A welding robot and the B welding robot determine the starting and ending points of movement through signal cooperation with the positioning devices.

[0008] As a further improvement of the present invention, in step S2, after the A welding robot stops welding when it reaches point b, the A welding robot will perform automatic grinding on the arc - ending joint at point b; after the B welding robot stops welding when it reaches point a, the B welding robot will perform automatic grinding on the arc - ending joint at point a.

[0009] As a further improvement of the present invention, during the process of the B welding robot performing automatic backward movement in step S3, when the B welding robot reaches point d, it will pause the backward movement, perform automatic grinding on the arc - starting joint at point d, and continue the automatic backward movement after the grinding is completed.

[0010] As a further improvement of the present invention, in step S4, after the A welding robot stops welding when it reaches point a, the A welding robot will perform automatic grinding on the arc - ending joint at point a; after the B welding robot stops welding when it reaches point d, the B welding robot will perform automatic grinding on the arc - ending joint at point d.

[0011] As a further improvement of the present invention, in step S5, after the A welding robot reaches point b, it will perform automatic grinding on the arc - starting joint at point b; after the B welding robot reaches point c, it will perform automatic grinding on the arc - starting joint at point c.

[0012] Beneficial effects Compared with the prior art, the advantages of an automatic welding method for penstocks of the present invention are as follows: 1. During the welding process of Welding Robot A and Welding Robot B in this method, the welding heat-affected zone always maintains a centrosymmetric distribution on both sides of the penstock. Compared with the situation where the welding heat-affected zone of the existing welding method gradually transfers from bottom to top, this method avoids the uneven thermal expansion and contraction of the penstock, thus significantly reducing the deformation risk of the overall structure of the penstock. At the same time, the weld segments completed by Welding Robot A and Welding Robot B respectively are rotationally symmetric about the center of the steel pipe, which also balances the shrinkage stresses generated by welding on both sides of the penstock and reduces warping or twisting caused by stress concentration.

[0013] 2. By reasonably controlling the collaborative operation process of the two welding robots, this method can reduce the ineffective waiting time and improve the overall welding efficiency and automation rate.

[0014] Through the following description and in combination with the accompanying drawings, the present invention will become clearer. These drawings are used to explain the embodiments of the present invention. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of the welding paths of the two welding robots in step S2; Figure 2 It is a schematic diagram of the moving path of Welding Robot B in step S3; Figure 3 It is a schematic diagram of the welding paths of the two welding robots in step S4; Figure 4 It is a schematic diagram of the moving paths of the two welding robots in step S5; Figure 5 It is a schematic diagram of the moving paths of the two welding robots in step S6. Detailed Embodiment

[0017] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following will further describe the present invention in detail in combination with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; of course, it may also be a mechanical connection or an electrical connection; additionally, it may be a direct connection, an indirect connection through an intermediate medium, or a communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] Now, embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] Embodiment The specific implementation manner of the present invention is as Figures 1-5 shown. An automatic welding method for penstocks includes the following steps: S1. First, butt two penstocks together to form a weld at the butt joint, and install a welding robot A and a welding robot B on the weld that can move along the extension direction of the weld and perform welding operations; then, evenly divide the cross-section of the weld of the two penstocks into four segments in the clockwise direction, and the starting points of each segment are a, b, c, and d respectively; S2. The welding robot A starts arcing from point c, and the welding robot B starts arcing from point d simultaneously, and starts welding from bottom to top synchronously with preset parameters until the welding robot A stops welding after reaching point b, and the welding robot B stops welding after reaching point a; S3. The welding robot B performs an automatic retraction until the welding robot B stops retracting after reaching point c; S4. The welding robot A starts arcing from point b, and the welding robot B starts arcing from point c simultaneously, and starts welding from bottom to top synchronously with preset parameters until the welding robot A stops welding after reaching point a, and the welding robot B stops welding after reaching point d; S5. The welding robot A and the welding robot B perform an automatic retraction simultaneously until the welding robot A stops retracting after reaching point b and the welding robot B stops retracting after reaching point c; S6. The welding robot A performs an automatic retraction until the welding robot A stops retracting after reaching point c. At the same time, the welding robot B performs an automatic advancement until the welding robot B stops advancing after reaching point d; S7. Repeat steps S2 - S6 until the welding of the two penstocks is completed.

[0021] In this welding method, both the A welding robot and the B welding robot adopt a two-stage welding method to synchronously complete the welding of the weld segments they are responsible for, and in the same welding stage, the weld segments welded by the A welding robot and the B welding robot are rotationally symmetric about the center of the steel pipe. Therefore, during the welding process of the A welding robot and the B welding robot, the welding heat-affected zones are always symmetrically distributed at the centers on both sides of the penstock. Compared with the situation where the welding heat-affected zone of the existing welding method gradually transfers from bottom to top, this method avoids the uneven thermal expansion and contraction of the penstock, thus significantly reducing the deformation risk of the overall structure of the penstock. At the same time, the weld segments welded by the A welding robot and the B welding robot are rotationally symmetric about the center of the steel pipe, which also balances the shrinkage stresses generated by welding on both sides of the penstock, thereby reducing warping or twisting caused by stress concentration. In addition, by reasonably controlling the collaborative operation process of the two welding robots, this method can reduce the ineffective waiting time and improve the overall welding efficiency and automation rate.

[0022] In this method, in order to accurately control the movement of the A welding robot and the B welding robot in each step, positioning devices are installed on the penstock beside the four starting points a, b, c, and d. Both the A welding robot and the B welding robot determine the starting and ending points of movement through signal cooperation with the positioning devices. In this implementation, the positioning device can adopt an infrared signal emitter. Correspondingly, infrared signal receivers that can receive infrared signals are installed on the A welding robot and the B welding robot, and the infrared signal receivers are electrically connected to the controllers of the A welding robot and the B welding robot, so that both the A welding robot and the B welding robot can determine the starting and ending points of movement based on the received infrared signals. Of course, in the actual production process, the positioning device is not limited to the infrared signal positioning device, and other types of positioning devices can also be selected according to actual needs.

[0023] At the same time, both the A welding robot and the B welding robot in this embodiment are pipeline welding robots with the function of grinding the starting / ending arc joints.

[0024] Since both the A welding robot and the B welding robot have the function of grinding the starting / ending arc joints. Therefore, in step S2, when the A welding robot reaches point b and stops welding, the A welding robot will perform automatic grinding of the ending arc joint at point b; when the B welding robot reaches point a and stops welding, the B welding robot will perform automatic grinding of the starting arc joint at point a.

[0025] During the process of the B welding robot performing automatic retraction in step S3, after the B welding robot reaches point d, it will pause the retraction, perform automatic grinding of the starting arc joint at point d, and continue to perform automatic retraction after the grinding is completed.

[0026] In step S4, after the A welding robot reaches point a and stops welding, the A welding robot will perform automatic grinding on the arc starting joint at point a; after the B welding robot reaches point d and stops welding, the B welding robot will perform automatic grinding on the arc starting joint at point d.

[0027] In step S5, after the A welding robot reaches point b, it will perform automatic grinding on the arc starting joint at point b; after the B welding robot reaches point c, it will perform automatic grinding on the arc starting joint at point c.

[0028] The present invention has been described in conjunction with the best embodiments, but the present invention is not limited to the disclosed embodiments above, and should cover various modifications and equivalent combinations made according to the essence of the present invention.

Claims

1. An automatic welding method for penstocks, characterized in that, It includes the following steps: S1. Divide the weld cross-sections of two penstocks into four sections in the clockwise direction, and the starting points of each section are a, b, c, and d respectively; S2. Welding robot A starts arc striking from point c, and welding robot B starts arc striking from point d simultaneously, and starts welding from bottom to top synchronously with preset parameters until welding robot A stops welding after reaching point b and welding robot B stops welding after reaching point a; S3. Welding robot B performs automatic retraction until welding robot B stops retracting after reaching point c; S4. Welding robot A starts arc striking from point b, and welding robot B starts arc striking from point c simultaneously, and starts welding from bottom to top synchronously with preset parameters until welding robot A stops welding after reaching point a and welding robot B stops welding after reaching point d; S5. Welding robot A and welding robot B perform automatic retraction simultaneously until welding robot A stops retracting after reaching point b and welding robot B stops retracting after reaching point c; S6. Welding robot A performs automatic retraction until welding robot A stops retracting after reaching point c. At the same time, welding robot B performs automatic advancement until welding robot B stops advancement after reaching point d; S7. Repeat steps S2 - S6 until the welding of two penstocks is completed.

2. The automatic welding method for penstock according to claim 1, characterized in that Positioning devices are installed on the penstocks beside the four starting points a, b, c, and d. Welding robot A and welding robot B determine the starting and ending points of movement through signal cooperation with the positioning devices.

3. The automatic welding method for penstock according to claim 1 or 2, characterized in that, In step S2, after welding robot A stops welding after reaching point b, welding robot A will perform automatic grinding on the arc striking joint at point b; after welding robot B stops welding after reaching point a, welding robot B will perform automatic grinding on the arc striking joint at point a.

4. The automatic welding method for penstock according to claim 3, characterized in that, During the automatic retraction of welding robot B in step S3, welding robot B will pause retraction after reaching point d, perform automatic grinding on the arc striking joint at point d, and continue automatic retraction after the grinding is completed.

5. The automatic welding method for penstock according to claim 4, characterized in that, In step S4, after welding robot A stops welding after reaching point a, welding robot A will perform automatic grinding on the arc striking joint at point a; after welding robot B stops welding after reaching point d, welding robot B will perform automatic grinding on the arc striking joint at point d.

6. The automatic welding method for penstock according to claim 5, characterized in that, In step S5, after welding robot A reaches point b, it will perform automatic grinding on the arc striking joint at point b; after welding robot B reaches point c, it will perform automatic grinding on the arc striking joint at point c.

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