Anti-deformation tool and welding method for welding safety end of pipe

Abstract

The present invention provides an anti-deformation tool and welding method for welding a safety end of a pipe. The anti-deformation tool for welding a safety end of a pipe comprises: a screw, a nut, a first adjustment block and a second adjustment block; the screw is fixedly connected to the first adjustment block, the second adjustment block abuts between the first adjustment block and the nut, and the screw and the nut are connected by threaded fit; the first adjustment block and the second adjustment block are both provided with an inner cavity, and the diameter of the inner cavity is larger than the outer diameter of the screw; the first adjustment block is also provided with a first inclined surface, and the second adjustment block is also provided with a second inclined surface, and the two inclined surfaces abut each other; when the nut rotates, the second adjustment block generates relative displacement with the first adjustment block along the first inclined surface; the first adjustment block and the second adjustment block are respectively used to abut against the inner liner of the safety end component and the pipe component. The present invention adjusts the nut to cause the two adjustment blocks to generate relative displacement, so that they abut against the inner liner of the pipe and the safety end, respectively, thereby reducing deformation during the welding process of the safety end of the pipe and improving the dimensional accuracy after welding.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, and in particular to an anti-deformation tool for welding a safety end of a pipe and a welding method. Background Art

[0002] The nuclear reactor pressure vessel is an important component of the nuclear reactor. Its quality is the key to ensuring the normal and safe operation of nuclear power equipment and nuclear power plants. The nozzle and safety end in the reactor pressure vessel are important components of the circuit pressure boundary. During the operation of nuclear power plant equipment, they are subjected to the alternating complex stress of high temperature and high pressure. If the welding deformation generated during the welding of the nozzle and safety end is large, the stress cycle caused by the thermal cycle will cause fatigue failure of the weld prematurely, seriously affecting the safe operation of the pressure vessel.

[0003] In recent years, with the rapid development of the nuclear energy industry, the industry has invested more and more in the research and development of welding-related technologies for pressure vessels and their important components. Most of the existing technologies rely on the structure of the fixture itself to clamp the outside of the pipe and the safety end to provide fastening force during the welding process to prevent large deformation during the welding process. Although the external welding deformation can be controlled to a certain extent, for welding products such as small-diameter pipes and safety ends with liner pipes inside, even if the fixture is used to apply fastening force on the outside, the internal liner may have large welding deformation as the length changes during the welding process, affecting the dimensional accuracy of the pipe safety end welding. The dimensional accuracy of the pipe safety end welding also directly affects the reliability of the pipe safety end. Summary of the Invention

[0004] The problem solved by the present invention is how to reduce the deformation of the inner liner of the pipe safety end caused by welding, so as to improve the dimensional accuracy of the welding of the pipe safety end.

[0005] In order to solve the above problems, the present invention provides an anti-deformation tool for welding the safety end of a pipe, comprising: a screw, a nut, a first adjusting block and a second adjusting block; the screw is fixedly connected to the first adjusting block, the second adjusting block abuts between the first adjusting block and the nut, and the screw and the nut are connected by threaded cooperation; the first adjusting block and the second adjusting block are both provided with an inner cavity, and the diameter of the inner cavity is larger than the outer diameter of the screw; the first adjusting block is also provided with a first inclined surface, and the second adjusting block is also provided with a second inclined surface, and the first inclined surface abuts the second inclined surface; when the nut rotates, the second adjusting block generates a relative displacement with the first adjusting block along the first inclined surface, and the first adjusting block and the second adjusting block are respectively used to abut against the inner liner pipe and the pipe component of the safety end component.

[0006] Optionally, the first adjustment block is further provided with a first contact surface for abutting the inner liner tube, and the second adjustment block is further provided with a second contact surface for abutting the connecting pipe component, and the first contact surface and the second contact surface are both in the shape of arc surfaces.

[0007] Optionally, the top surface of the nut is provided with a scale line, and the scale line is provided with a corresponding displacement value, and the displacement value is obtained based on the size of the anti-deformation tool used for welding the safety end of the pipe; the bottom surface of the screw is provided with a groove, and when the groove corresponds to the scale line, it is used to indicate the displacement value of the relative displacement.

[0008] Compared with the prior art, the structure of the anti-deformation tool for welding the safety end of the pipe of the present invention includes a fixedly connected screw and a first adjustment block, a second adjustment block abutting between the first adjustment block and the nut, the nut and the screw are matched through threads, the structure is simple and compact, and it is conducive to meeting the use requirements of narrow spaces; the first adjustment block and the second adjustment block are both provided with an inner cavity, and the diameter of the inner cavity is larger than the outer diameter of the screw, providing space for the adjustment block to move relative to the screw; the first adjustment block and the second adjustment block are also provided with inclined surfaces abutting each other, and when the nut is rotated, the distance between the nut and the screw increases or decreases, so that the first adjustment block and the second adjustment block A relative deviation displacement is generated relative to the inclined surface, and the deviation displacement increases. The first adjustment block and the second adjustment block are respectively in contact with the inner liner tube and the connecting pipe component of the safety end component, which can support the internal liner gap of the connecting pipe safety end and reduce the deformation generated during the welding process of the connecting pipe safety end, so as to improve the dimensional accuracy of the connecting pipe safety end after welding; the deviation displacement is reduced, which can separate the two adjustment blocks from the connecting pipe and the inner liner tube, so that the anti-deformation tool for welding the connecting pipe safety end can be easily removed after welding is completed without affecting the dimensional accuracy of the supporting part. The disassembly and assembly are more convenient, the welding operation efficiency is improved, and the dimensional accuracy after welding is guaranteed.

[0009] On the other hand, the present invention also provides a method for welding a pipe safety end. Based on the above-mentioned anti-deformation tool for welding a pipe safety end, the pipe safety end includes a pipe component and a safety end component, the outer surface of the pipe component is provided with a first side slope; the safety end component includes an inner liner, and the outer surface of the safety end component is provided with a second side slope. The pipe safety end welding method includes the following steps:

[0010] The connecting pipe component and the safety end component are brought into contact with each other, and the first side slope surface and the second side slope surface form a welding groove;

[0011] Performing a first welding on the welding groove from a preset first arc starting position;

[0012] Installing an anti-deformation tool for welding the safety end of the pipe in the annular gap formed between the pipe component and the liner pipe, the anti-deformation tool for welding the safety end of the pipe is used to support the annular gap;

[0013] measuring the gap size of the annular gap to obtain a first size data set;

[0014] Adjusting the anti-deformation tool for welding the pipe safety end based on the first size data group;

[0015] Welding the welding groove from a preset second arc starting position;

[0016] measuring the gap size of the annular gap to obtain a second size data set;

[0017] determining the second arc starting position for the next welding according to the second size data group;

[0018] Return to the step of welding the welding groove from the preset second arc starting position until the welding groove is fully welded.

[0019] Optionally, measuring the gap size of the annular gap to obtain a first size data set includes:

[0020] Measuring at least two preset measurement positions in the annular gap using a deformation measurement tool, wherein the deformation measurement tool comprises a plurality of cylindrical rods having a dimensional accuracy greater than a preset first accuracy threshold, and wherein the diameters of the cylindrical rods are arranged in a gradient;

[0021] The diameter corresponding to the largest cylindrical rod that can be placed at the measurement position is used as the gap size;

[0022] The measurement position and the corresponding gap size are recorded to obtain the first size data set.

[0023] Optionally, the cylindrical rod includes a preset standard rod; and before measuring at least two preset measurement positions in the annular gap using the deformation measurement tool, the method further includes:

[0024] Determining whether the standard rod can be placed at the measurement position;

[0025] If the standard rod cannot be placed at the measurement position, the cylindrical rod having a diameter smaller than that of the standard rod is selected to measure the annular gap;

[0026] If the standard rod can be placed at the measurement position, the cylindrical rod having a diameter larger than that of the standard rod is selected to measure the measurement position.

[0027] Optionally, adjusting the anti-deformation tool for welding the pipe safety end based on the first size data group includes:

[0028] Calculating a position error between the connecting pipe component and the inner liner pipe based on the first size data group;

[0029] Determining whether the position error is greater than a preset first error threshold;

[0030] If the position error is greater than the first error threshold, an adjustment angle and an adjustment direction of the anti-deformation tool for welding the pipe safety end are determined based on the first size data group.

[0031] Optionally, the second size data set includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; and determining the second arc starting position for the next welding according to the second size data set includes:

[0032] Arrange the data sequence in descending order of the gap sizes;

[0033] Taking the measurement position corresponding to the largest gap size in the data sequence as the maximum deformation position;

[0034] A position on the welding groove corresponding to the maximum deformation is selected as the second arc starting position.

[0035] Optionally, the second size data set includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; and determining the second arc starting position for the next welding according to the second size data set includes:

[0036] Calculating the position error based on the second size data set;

[0037] determining a deviation direction of the liner pipe based on the position error;

[0038] The position of the welding groove corresponding to the direction opposite to the offset direction is selected as the second arc starting position.

[0039] Optionally, after returning to the preset second arc starting position and welding the welding groove until the welding groove is fully welded, the method further includes:

[0040] measuring the gap size of the annular gap to obtain a third size data set;

[0041] Calculating the position error based on the third size data set;

[0042] Determining whether the position error is less than a preset second error threshold;

[0043] If the position error is less than the second error threshold, the welding of the pipe safety end is evaluated as qualified;

[0044] Rotate the nut of the anti-deformation tool for welding the safety end of the pipe according to the preset rotation direction, and take out the anti-deformation tool for welding the safety end of the pipe.

[0045] Compared with the prior art, the present invention installs an anti-deformation tool for welding the pipe safety end in the annular gap formed between the inner liner pipe of the pipe pipe component and the safety end component after assembling the pipe pipe component and the safety end component to form a welding groove and perform the first welding, thereby providing support force for the annular gap of the inner liner pipe of the pipe safety end, which is beneficial to reducing the deformation degree of the annular gap in the subsequent welding process and improving the dimensional accuracy of the welding of the pipe safety end; at the same time, after the anti-deformation tool for welding the pipe safety end is installed, the gap size of the annular gap is measured and the anti-deformation tool for welding the pipe safety end is adjusted based on this, thereby further improving the dimensional accuracy of the annular gap; due to the characteristics of welding, the shrinkage of the welding arc starting position is large, and by measuring the gap size after each welding and determining the arc starting position of the next welding based on the gap size, the dimensional deviation generated in the welding process is compensated and the size is continuously corrected, which is beneficial to ensure that the pipe safety end still maintains a high dimensional accuracy after the welding is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a cross-sectional view of the structure of an anti-deformation tool for welding a pipe safety end according to an embodiment of the present invention;

[0047] Figure 2 Schematic diagram of the installation position of the anti-deformation tool for welding the safety end of the pipe according to an embodiment of the present invention;

[0048] Figure 3 This is a schematic structural diagram of an anti-deformation tool for welding a pipe safety end according to an embodiment of the present invention;

[0049] Figure 4 This is another structural schematic diagram of the anti-deformation tool for welding the safety end of the pipe according to an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of welding of a pipe safety end welding method according to an embodiment of the present invention;

[0051] Figure 6 This is a flow chart of a method for welding a safety end of a pipe according to an embodiment of the present invention;

[0052] Figure 7 This is a detailed flowchart of step S400 of the method for welding the safety end of the pipe according to an embodiment of the present invention;

[0053] Figure 8This is a flowchart of a detailed step S410 of the method for welding a safety end of a pipe according to an embodiment of the present invention;

[0054] Figure 9 This is a detailed flowchart of step S500 of the method for welding the safety end of a pipe according to an embodiment of the present invention;

[0055] Figure 10 Schematic diagram of step S500 of the method for welding a safety end of a pipe according to an embodiment of the present invention;

[0056] Figure 11 This is a flowchart of a detailed step S800 of the method for welding a safety end of a pipe according to an embodiment of the present invention;

[0057] Figure 12 This is another flowchart after refinement of step S800 of the method for welding the safety end of the pipe according to an embodiment of the present invention;

[0058] Figure 13 This is a flowchart of a detailed step S900 of the method for welding a safety end of a pipe according to an embodiment of the present invention.

[0059] Description of reference numerals:

[0060] 1-Anti-deformation tool for welding the safety end of the pipe; 11-Screw; 111-Groove; 12-First adjustment block; 121-First bevel; 122-First contact surface; 13-Second adjustment block; 131-Second bevel; 132-Second contact surface; 14-Nut; 141-Scale line; 142-Displacement value; 2-Pipe connection component; 21-First side slope; 3-Safety end component; 31-Inner liner; 32-Second side slope; 4-Welding groove; 5-Annular gap. DETAILED DESCRIPTION

[0061] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0062] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0063] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0064] It should be noted that the modifications of "one" and "multiple" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0065] In the description of the present invention, it should be understood that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 should not be understood as a limitation on the present invention.

[0066] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides an anti-deformation tool 1 for welding a safety end of a pipe, comprising: a screw 11, a nut 14, a first adjusting block 12 and a second adjusting block 13; the screw 11 is fixedly connected to the first adjusting block 12, the nut 14 is detachably connected to the second adjusting block 13, and the screw 11 and the nut 14 are connected by threaded cooperation; the first adjusting block 12 and the second adjusting block 13 are both provided with an inner cavity, and the diameter of the inner cavity is greater than the outer diameter of the screw 11; the first adjusting block 12 is also provided with a first inclined surface 121, and the second adjusting block 13 is also provided with a second inclined surface 131, and the first inclined surface 121 abuts against the second inclined surface 131; when the nut 14 rotates, the second adjusting block 13 generates a relative displacement with the first adjusting block 12 along the first inclined surface 121, and the first adjusting block 12 and the second adjusting block 13 are respectively used to abut against the inner liner 31 of the safety end component 3 and the pipe component 2.

[0067] Specifically, the anti-deformation tool 1 for welding the safety end of the pipe includes a screw 11, a nut 14, a first adjustment block 12 and a second adjustment block 13, wherein the screw 11 is fixedly connected to the first adjustment block 12, for example, the screw 11 and the first adjustment block 12 can be connected by means of a snap, a pin or a thread; preferably, the fixed connection method is welding; the second adjustment block 13 abuts between the first adjustment block 12 and the nut 14, and the screw 11 and the nut 14 are connected by threaded cooperation. The first adjustment block 12 and the second adjustment block 13 are both provided with an inner cavity, and the diameter of the inner cavity is larger than the outer diameter of the screw 11, wherein the inner cavity diameter of the first adjustment block 12 only needs to be able to pass through the screw 11, and can be the same as the inner cavity diameter of the second adjustment block 13, or can be smaller than the inner cavity diameter of the second adjustment block 13 and larger than the diameter of the screw 11; for example, the outer diameter of the screw 11 is 6 mm, the inner cavity diameters of the first adjustment block 12 and the second adjustment block 13 are both 10 mm, or the inner cavity diameter of the first adjustment block 12 is 8 mm, and the inner cavity size of the second adjustment block 13 is 12 mm.

[0068] In one embodiment, the first adjustment block 12 further includes a first bevel 121, and the second adjustment block 13 further includes a second bevel 131. These two bevels abut against each other. When the nut 14 rotates, the second adjustment block 13 moves relative to the first adjustment block 12 along the direction of the first bevel 121, causing the originally parallel surfaces of the first and second adjustment blocks 12, 13, to become misaligned. This increases the distance between the pipe safety end welding anti-deformation tool 1 in the thickness direction, allowing the first and second adjustment blocks 12, 13 to abut against the inner liner 31 of the safety end component 3 and the pipe component 2, respectively.

[0069] Optionally, a flat washer or a spring washer may be provided between the second adjustment block 13 and the nut 14 to prevent the nut 14 from loosening due to vibration during the welding process and to maintain stable dimensional accuracy.

[0070] Optionally, the anti-deformation tool 1 for welding the safety end of the pipe can also be fixedly connected to the second adjustment block 13 using a nut 14, and the first adjustment block 12 abuts against the head of the screw 11 and the second adjustment block 13. The functional effect produced by this structure is the same as the above structure.

[0071] In this embodiment, the structure of the anti-deformation tool 1 for welding the safety end of the pipe includes a screw 11 and a first adjustment block 12 that are fixedly connected, a second adjustment block 13 that abuts between the first adjustment block 12 and the nut 14, and the nut 14 and the screw 11 are matched by threads, and the structure is simple and compact, which is conducive to meeting the use requirements of narrow spaces; the first adjustment block 12 and the second adjustment block 13 are both provided with an inner cavity, and the diameter of the inner cavity is greater than the outer diameter of the screw 11, providing space for the adjustment block to move relative to the screw 11; the first adjustment block 12 and the second adjustment block 13 are also provided with inclined surfaces abutting each other, and when the nut 14 rotates, the distance between the nut 14 and the screw 11 increases or decreases, so that the first adjustment block 12 and the second adjustment block 13 are relative to the inclined surfaces. A relative deviation displacement is generated, and the deviation displacement increases. The first adjustment block 12 and the second adjustment block 13 are respectively abutted against the inner liner 31 of the safety end component 3 and the connecting pipe component 2, so that the anti-deformation tool 1 for welding the connecting pipe safety end can fit the connecting pipe component 2 and the inner liner 31 at the same time, support the internal liner gap of the connecting pipe safety end, reduce the deformation during the welding process of the connecting pipe safety end, and improve the dimensional accuracy of the connecting pipe safety end after welding; the deviation displacement is reduced, which can separate the two adjustment blocks from the connecting pipe 2 and the inner liner 31, so that the anti-deformation tool 1 for welding the connecting pipe safety end can be easily removed after welding is completed without affecting the dimensional accuracy of the supported part, making disassembly and assembly more convenient, improving welding operation efficiency, and ensuring dimensional accuracy after welding.

[0072] Alternatively, as Figure 3 As shown, the first adjustment block 12 is further provided with a first contact surface 122 for abutting the inner liner tube 31, and the second adjustment block 13 is further provided with a second contact surface 132 for abutting the connecting pipe component 2. The first contact surface 122 and the second contact surface 132 are both arc surfaces.

[0073] In one embodiment, both the first adjustment block 12 and the second adjustment block 13 are provided with arc-shaped contact surfaces, wherein the first contact surface 122 is configured to abut against the inner liner 31, and the second contact surface 123 is configured to abut against the connecting pipe component 2. For example, after the first adjustment block 12 and the second adjustment block 13 are relatively displaced by rotating the nut 14, the first contact surface 122 of the first adjustment block 12 abuts against the outer surface of the inner liner 31 of the safety end component 3, and the second contact surface 132 of the second adjustment block 13 abuts against the inner surface of the connecting pipe component 2.

[0074] Optionally, the arc shape of the contact surface is adapted to the arc surface that needs to abut. For example, the radius of the arc of the first contact surface 122 is similar to the radius of the outer surface of the liner pipe 31, and the radius of the arc of the second contact surface 132 is similar to the radius of the inner surface of the connecting pipe component 2, thereby improving the fit between the anti-deformation tool 1 for welding the safe end of the connecting pipe and the supported part.

[0075] Optionally, the shapes of the first contact surface 122 and the second contact surface 132 can be changed according to the gap shape of the installation position of the anti-deformation tool 1 for welding the safety end of the pipe. For example, when the gap between the pipe component 2 and the inner liner tube 31 of the safety end component 3 is two parallel planes, the shapes of the first contact surface 122 and the second contact surface 132 are also correspondingly planes, thereby increasing the contact area between the contact surface and the abutted part.

[0076] In this embodiment, the first adjustment block 12 and the second adjustment block 13 are both provided with arc-shaped contact surfaces. The first contact surface 122 is used to abut against the inner lining pipe 31, and the second contact surface 123 is used to abut against the connecting pipe component 2, thereby improving the fit between the anti-deformation tool 1 for welding the safety end of the connecting pipe and the abutted part, and providing better support for the abutted part.

[0077] Alternatively, as Figure 4 As shown, the top surface of the nut 14 is provided with a scale line 141, and the scale line 141 is provided with a corresponding displacement value 142, which is obtained based on the size of the anti-deformation tool 1 for welding the safety end of the pipe; the bottom surface of the screw 11 is provided with a groove 111, and when the groove 111 corresponds to the scale line 141, it is used to indicate the displacement value 142 of the relative displacement.

[0078] In one embodiment, the top surface of the nut 14 is provided with scale lines 141, which can be protrusions, grooves 111 or spray-painted, and the scale lines 141 are provided with corresponding displacement values ​​142. At the same time, the bottom surface of the screw 11 is provided with grooves 111 for indicating the displacement value 142 of the relative displacement. For example, 12 equally divided scale lines 141 are set on the top surface of the nut 14, and the gap between each two scale lines 141 represents a rotation of 30°. The intercept P of the nut 14 is 2mm, that is, when the nut 14 rotates one circle, the distance between it and the screw 11 changes by 2mm; the bevel angle of the first adjustment block 12 and the second adjustment block 13 is greater than 30°, and preferably, the bevel angle is 45°; based on the bevel angle of the adjustment block and the pitch of the nut 14, it can be calculated that when the nut 14 rotates one circle, the relative displacement between the first adjustment block 12 and the second adjustment block 13 along the bevel is The relative horizontal displacement between the first adjustment block 12 and the second adjustment block 13 is 2 mm. Therefore, it can be calculated that for every 30° rotation of the nut 14, the relative horizontal displacement between the first adjustment block 12 and the second adjustment block 13 is approximately 0.167 mm. The displacement corresponding to each scale line 141 is marked on the corresponding scale. When adjusting the nut 14, the relative horizontal displacement between the first adjustment block 12 and the second adjustment block 13 can be intuitively seen using the position of the groove 111 at the bottom of the screw rod 11 as a reference.

[0079] In this embodiment, a scale line 141 is set on the top surface of the nut 14, and a corresponding displacement value 142 is obtained based on the size of the anti-deformation tool 1 for welding the safety end of the pipe is set on the scale line 141. The bottom surface of the screw 11 is provided with a groove 111, and the groove 111 corresponds to the scale line 141 and can indicate the displacement value 142 of the relative displacement, so that the horizontal relative displacement between the first adjustment block 12 and the second adjustment block 13 caused by the rotation of the nut 14 can be quantitatively displayed, which assists the user in judging the degree of adjustment, so that the adjustment of the anti-deformation tool 1 for welding the safety end of the pipe is more precise.

[0080] Another embodiment of the present invention provides a method for welding a pipe safety end, based on the pipe safety end welding anti-deformation tool 1 described above, as shown in FIG. Figure 5 As shown, the pipe safety end includes a pipe component 2 and a safety end component 3, the outer surface of the pipe component 2 is provided with a first side slope 21; the safety end component 3 includes an inner liner 31, and the outer surface of the safety end component 3 is provided with a second side slope 32.

[0081] like Figure 6 As shown, the welding method for the safety end of the pipe includes the following steps:

[0082] S100 : The connecting pipe component 2 and the safety end component 3 are brought into contact with each other, and the first side slope surface 21 and the second side slope surface 32 form a welding groove 4 .

[0083] Specifically, in one embodiment, the welding groove 4 of the present invention refers to a pre-machined form of the joint part or end face of the component to be welded, and common forms include I, V, U, Y, V, etc.; preferably, this embodiment adopts a U-shaped groove.

[0084] In this embodiment, the connecting pipe component 2 and the safety end component 3 are abutted against each other to form a welding groove 4, which is beneficial to ensuring the welding quality of the safety end of the mechanism.

[0085] S200: performing the first welding on the welding groove 4 from a preset first arc starting position.

[0086] Specifically, in one embodiment, the welding method adopts a single-sided welding and double-sided forming welding method to perform the first welding on the welding groove 4 from a preset first arc starting position, wherein the first welding refers to completing the welding at the root position of the welding groove 4;

[0087] In this embodiment, the welding groove 4 is welded for the first time from a preset first arc starting position to complete the preliminary connection and fixation of the connecting pipe and the safety end, so that a relatively stable positional relationship is formed between the connecting pipe component 2 and the inner liner pipe 31.

[0088] S300 : Installing the anti-deformation tool 1 for welding the safety end of the pipe into the annular gap 5 formed between the pipe component 2 and the liner pipe 31 . The anti-deformation tool 1 for welding the safety end of the pipe is used to support the annular gap 5 .

[0089] In one embodiment, the anti-deformation tool 1 for welding the safety end of the pipe is installed in the annular gap 5 formed between the pipe component 2 and the inner liner pipe 31. For example, the anti-deformation tool 1 for welding the safety end of the pipe is placed in the annular gap 5, and the nut 14 of the anti-deformation tool 1 for welding the safety end of the pipe is rotated clockwise to cause the first adjustment block 12 and the second adjustment block 13 of the anti-deformation tool 1 for welding the safety end of the pipe to produce relative displacement to support the annular gap 5. When the first contact surface 122 of the first adjustment block 12 abuts against the inner surface of the pipe component 2 and the second contact surface 132 of the second adjustment block 13 abuts against the outer surface of the inner liner pipe 31, stop rotating the nut 14 to complete the installation of the anti-deformation tool 1 for welding the safety end of the pipe.

[0090] In this embodiment, an anti-deformation tool 1 for welding the safety end of the pipe is installed in the annular gap 5 formed between the pipe component 2 and the inner liner pipe 31, thereby supporting the annular gap 5 and preventing large deformation during subsequent welding.

[0091] S400: measuring the gap size of the annular gap 5 to obtain a first size data set.

[0092] In one embodiment, the gap size of the annular gap 5 is measured by a measuring tool to obtain a first size data set, wherein the gap size can be measured by a standard measuring tool or by a gauge with a designed standard size to obtain the first size data set.

[0093] In this embodiment, the gap size of the annular gap 5 is measured to obtain a first size data set. The measurement data can reflect the dimensional deformation after welding and provide a data basis for subsequent adjustment steps.

[0094] S500: Adjusting the anti-deformation tool 1 for welding the pipe safety end based on the first size data group.

[0095] In one embodiment, the anti-deformation tool 1 for welding the safety end of the pipe is adjusted based on the first dimension data group. The first dimension data group can reflect the positional situation between the pipe component 2 and the safety end component 3. Adjusting the anti-deformation tool 1 for welding the safety end of the pipe based on this can improve the dimensional accuracy between the safety ends of the pipe.

[0096] S600: Welding the welding groove 4 from the preset second arc starting position.

[0097] In one embodiment, the welding groove 4 is welded from a preset second arc starting position. For example, the welding groove 4 can be welded through the horizontal welding position, the flat welding position, the vertical welding position and the overhead welding position. The horizontal welding position indicates that the surface to be welded is in an approximately vertical position, and welding is performed from a position where the weld axis is basically horizontal; the flat welding position indicates a welding position with a weld inclination angle of 0°-5° and a weld rotation angle of 0°-10°; the vertical welding position indicates a welding position with a weld inclination angle of 80°-90° and a weld rotation angle of 0°-180°; the overhead welding position indicates that when the surface to be welded is in an approximately horizontal position, welding is performed from under the joint; preferably, this embodiment uses the horizontal welding position to weld the welding groove 4, and the welding effect is better.

[0098] Optionally, the welding amount of the welding groove 4 each time can be determined according to the number of welding circles. For example, the welding equipment circles the welding groove 4 twice for one welding operation.

[0099] Optionally, the preset second arc starting position may be selected in a direction opposite to the preset first arc starting position.

[0100] In this embodiment, welding is performed on the welding groove 4 from the preset second arc starting position, so as to facilitate controlling welding deformation based on the principle that the welding shrinkage at the first welding position is greater.

[0101] S700: Measure the gap size of the annular gap 5 to obtain a second size data set.

[0102] In one embodiment, after one welding, the gap size of the annular gap 5 is measured by a measuring tool to obtain a second size data set, wherein the gap size can be measured by a standard measuring tool or by a gauge of a designed standard size to obtain the second size data set.

[0103] In this embodiment, the second size data set is obtained by measuring the gap size of the annular gap 5. The measurement data can reflect the dimensional deformation after welding and provide a data basis for subsequent welding adjustment steps.

[0104] S800: Determine a second arc starting position for the next welding according to the second size data group.

[0105] In one embodiment, the second arc starting position for the next welding is determined based on the second dimension data group. For example, the value in the second dimension data group is compared with the preset standard value to calculate the difference, and the weight coefficient of each direction is determined based on the difference, and then the second arc starting position is determined based on the weight coefficient.

[0106] In this embodiment, due to the characteristics of welding, the shrinkage of the welding arc starting position is large. By measuring the second dimension data group of the gap size after welding and determining the arc starting position of the next welding based on this, the dimensional deviation generated in the welding process is compensated to ensure the dimensional accuracy of the safety end of the pipe after welding.

[0107] S900: Return to the step of welding the welding groove from the preset second arc starting position until the welding groove is fully welded.

[0108] In one embodiment, based on the second arc starting position, the step of welding the welding groove from the preset second arc starting position is returned until the welding groove 4 is fully welded, and deformation compensation is performed after each welding.

[0109] Optionally, the measurement step and the welding adjustment step can be performed intermittently after the welding step, so that measurement and adjustment do not have to be performed after each welding, thereby improving overall efficiency. The arc starting position of the last welding can also be determined by measuring the annular gap 5 and determining the second arc starting position before the last welding, so as to make a one-time correction to the deformation caused by welding and further improve the working efficiency.

[0110] In this embodiment, the second arc starting position is determined by measuring the size of the annular gap 5 after welding, and the deformation caused by welding is compensated and corrected to ensure the dimensional accuracy of the safety end of the pipe after welding.

[0111] In this embodiment, after assembling the pipe connecting part 2 and the safety end part 3 to form the welding groove 4 and performing the first welding, an anti-deformation tool 1 for welding the pipe safety end is installed in the annular gap 5 formed between the pipe connecting part 2 and the safety end liner pipe 31, so as to provide support for the annular gap 5, which is beneficial to reducing the deformation degree of the annular gap 5 in the subsequent welding process; at the same time, after installing the anti-deformation tool 1 for welding the pipe safety end, the gap size of the annular gap 5 is measured and the anti-deformation tool 1 for welding the pipe safety end is adjusted based on this, so as to improve the dimensional accuracy of the annular gap 5; due to the characteristics of welding, the shrinkage of the welding arc starting position is large. By measuring the gap size after each welding and determining the arc starting position of the next welding based on the gap size, the dimensional deviation generated in the welding process is compensated and the size is continuously corrected, which is beneficial to ensure that the pipe safety end still maintains a high dimensional accuracy after the welding is completed.

[0112] Alternatively, as Figure 7 As shown, the gap size of the annular gap 5 is measured to obtain a first size data set, including:

[0113] S410: measuring at least two preset measurement positions in the annular gap 5 using a deformation measurement tool, wherein the deformation measurement tool comprises a plurality of cylindrical rods having a dimensional accuracy greater than a preset first accuracy threshold, and the diameters of the cylindrical rods are arranged in a gradient;

[0114] S420: Taking the diameter of the largest cylindrical rod that can be placed at the measurement position as the gap size;

[0115] S430: Record the measurement position and the corresponding gap size to obtain a first size data set.

[0116] In one embodiment, a deformation measurement tool is used to measure at least two predetermined measurement locations within the annular gap 5. The deformation measurement tool includes a plurality of cylindrical rods having a dimensional accuracy greater than a predetermined first accuracy threshold. The diameters of the cylindrical rods are arranged in a gradient. The diameter of the largest cylindrical rod that can be placed at the measurement location is used as the gap size to obtain a first dimensional data set. For example, the standard size of the annular gap 5 is 20 mm, and the predetermined deviation of the annular gap 5 is ±5 mm. A series of cylindrical rods with diameters ranging from 15 mm to 25 mm are designed with a gradient of 0.1 mm. Preferably, the dimensional deviation of the cylindrical rods is less than ±0.01 mm. The cylindrical rods are placed in ascending order of diameter at the predetermined measurement locations until the gap at the measurement location can no longer accommodate the cylindrical rods. The diameter of the last cylindrical rod that can fit into the gap is recorded as the gap size at that measurement location. Based on this method, the gap sizes of at least two locations are measured, and the measurement locations and corresponding measured dimensions are recorded to form a first dimensional data set.

[0117] In this embodiment, a series of cylindrical rods with standard diameters are designed as inspection tools to measure the gap size of the annular gap 5, thereby obtaining high-precision dimensional data of the annular gap 5, avoiding human errors caused by measuring the annular gap 5 using measuring tools, and quantitatively displaying the deformation of the safety end of the pipe.

[0118] Alternatively, as Figure 8 As shown, the cylindrical rod includes a preset standard rod; before using the deformation measurement tool to measure at least two preset measurement positions in the annular gap 5, it also includes:

[0119] S411: Determine whether a standard rod can be placed at the measurement position;

[0120] S412: If the standard rod cannot be placed at the measurement position, a cylindrical rod with a diameter smaller than the standard rod is selected to measure the annular gap 5;

[0121] S413: If a standard rod can be placed at the measurement position, a cylindrical rod with a diameter larger than the standard rod is selected to measure the measurement position.

[0122] In one embodiment, the cylindrical rod includes a preset standard rod, for example, a cylindrical rod with a standard gap size as a diameter; before using a deformation measuring tool to measure at least two preset measurement positions in the annular gap 5, it is first determined whether the standard rod can be placed at the measurement position. If it cannot be placed, it means that the gap at this position is too small due to deformation, and a cylindrical rod with a diameter smaller than the standard rod should be used to check the gap; if it can be placed, it means that the gap at this position is too large due to deformation, and a cylindrical rod with a diameter larger than the standard rod should be used to check the gap.

[0123] In this embodiment, before performing precise quantitative measurement of the position to be measured, a standard rod is used to perform a qualitative inspection of the deformation of the position, and a cylindrical rod with a suitable diameter is selected for precise inspection based on the qualitative inspection result, which greatly improves the measurement efficiency of the annular gap 5 size.

[0124] Alternatively, as Figure 9 As shown, adjusting the anti-deformation tool 1 for welding the pipe safety end based on the first size data group includes:

[0125] S510: Calculating the position error between the connecting pipe component 2 and the inner liner pipe 31 based on the first size data group;

[0126] S520: Determine whether the position error is greater than a preset first error threshold;

[0127] S530: If the position error is greater than the first error threshold, determining the adjustment angle and adjustment direction of the anti-deformation tool 1 for welding the pipe safety end based on the first size data group.

[0128] In one embodiment, after calculating the position error between the pipe component 2 and the liner pipe 31 based on the first size data group, it is determined whether the position error is greater than a preset first error threshold. If it is greater, the position error is calculated based on the first size data group to determine the adjustment angle and adjustment direction of the anti-deformation tool 1 for welding the pipe safety end; for example, Figure 10As shown, the position error referred to in this embodiment represents the deviation of the center of the circle relative to the reference; four anti-deformation tools 1 for welding the safety end of the pipe are evenly installed in the middle of the annular gap 5 around the circumferential direction, and four spare gaps are formed between the anti-deformation tools 1 for welding the safety end of the pipe and the annular gap 5. In the four spare gaps, at least two measurement positions are selected to measure the gap size using a cylindrical rod; preferably, four measurement positions are selected for measurement, and the measurement positions and corresponding gap sizes are recorded to form a first dimension data group; since the cylindrical rod used when measuring the gap size can be regarded as being tangent to the inner surface of the pipe and the outer surface of the liner 31 at the same time, based on the known measurement positions, gap sizes and inner diameter sizes of the pipe and outer diameter sizes of the liner 31 in the first dimension data group, after geometric conversion, the relative position of the center of the circle where the outer surface of the liner 31 is located can be obtained, and then its offset vector relative to the center of the inner circle of the pipe is determined, including the offset size and offset direction.

[0129] In one embodiment, it is determined whether the position error is greater than a preset first error threshold. For example, the first error threshold can be determined according to the actual accuracy requirement. Preferably, the first error threshold is 0.1 mm. If the obtained position error is 0.3 mm, it means that the deformation of the pipe safety end is too large, and the anti-deformation tool 1 for welding the pipe safety end needs to be adjusted to correct the deformation. The adjustment angle and adjustment direction required for the nut 14 of the anti-deformation tool 1 for welding the pipe safety end are determined based on the first size data group.

[0130] Optionally, a historical calculation database can be established by collecting historical dimensional data sets, dimensional parameters of pipe safety ends, installation locations of pipe safety end welding anti-deformation tools 1, and corresponding adjustment angles and directions. This database then forms a mapping relationship table between the data sets and the adjustment angles and directions for the user to review. By arranging the pipe safety end welding anti-deformation tools 1 in the same location and measuring the gap data at the same location, the mapping relationship table can be consulted to obtain the specific values ​​that need to be adjusted for the corresponding pipe safety end welding anti-deformation tools 1, thus saving intermediate calculation steps and improving adjustment efficiency.

[0131] In this embodiment, the position error between the connecting pipe component 2 and the inner liner pipe 31 is calculated based on the first dimension data group, and it is determined whether the position error is greater than the preset first error threshold. If it is greater, it means that the dimensional accuracy deviation is too large and does not meet the preset requirements. It is necessary to determine the adjustment angle and adjustment direction of the anti-deformation tool 1 for welding the safety end of the connecting pipe based on the first dimension data group, which is conducive to accurately correcting the dimensional deviation and improving the dimensional accuracy.

[0132] Alternatively, as Figure 11As shown, the second size data set includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; determining the second arc starting position for the next welding according to the second size data set includes:

[0133] S810: Arrange the data sequence in descending order of gap size;

[0134] S820: taking the measurement position corresponding to the largest gap size in the data sequence as the maximum deformation position;

[0135] S830: Select the position on the welding groove 4 corresponding to the maximum deformation as the second arc starting position.

[0136] In one embodiment, the second dimension data group includes a data sequence consisting of at least two measurement positions and corresponding gap sizes. The data sequence is arranged in descending order of the gap size, and the measurement position corresponding to the largest gap size in the data sequence is the maximum deformation point. The position in the circumferential direction of the maximum deformation point corresponding to the circumferential direction of the welding groove 4 is selected as the second arc starting position, and the welding deformation is controlled by utilizing the welding characteristic that the arc starting position has a large shrinkage amount.

[0137] In this embodiment, the position where the annular gap deformation is most serious is found by selecting the measurement position corresponding to the largest gap size in the size data group, and the position on the welding groove 4 corresponding to the maximum deformation is selected as the second arc starting position. The welding deformation is controlled by utilizing the welding characteristic that the arc starting position has a large shrinkage amount, which provides an efficient method for correcting dimensional deformation for the welding of the safety end of the pipe, thereby improving work efficiency.

[0138] Alternatively, as Figure 12 As shown, the second size data set includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; determining the second arc starting position for the next welding according to the second size data set includes:

[0139] S840: Calculating a position error based on the second size data set;

[0140] S850: Determine the offset direction of the liner tube 31 based on the position error;

[0141] S860: Select the position of the welding groove 4 corresponding to the opposite direction of the offset direction as the second arc starting position.

[0142] In one embodiment, the second dimension data group includes a data sequence consisting of at least two measurement positions and corresponding gap dimensions. Since the cylindrical rod used to measure the gap dimension can be regarded as being tangent to both the inner surface of the connecting pipe and the outer surface of the liner tube 31, the position error of the center of the circle where the outer surface of the liner tube 31 is located relative to the center of the inner circle of the connecting pipe can be calculated based on the second dimension data combined with the dimensional parameters of the connecting pipe safety end. The position error includes the offset size and offset direction of the center of the circle where the liner tube 31 is located relative to the center of the circle where the connecting pipe component 2 is located, accurately reflecting the overall offset of the liner tube 31. The position on the welding groove 4 corresponding to the opposite direction of the offset direction is selected as the second arc starting position, and the welding deformation is controlled by utilizing the welding characteristic that the arc starting position has a large shrinkage amount.

[0143] In this embodiment, the position error between the connecting pipe component 2 and the inner liner pipe 31 is calculated by a data sequence consisting of at least two measurement positions and corresponding gap sizes. The position error includes the offset size and offset direction of the center of the inner liner pipe 31, which can accurately reflect the overall offset of the center of the inner liner pipe 31. The position on the welding groove 4 corresponding to the opposite direction of the offset direction is selected as the second arc starting position, and the welding deformation is controlled by utilizing the welding characteristic that the arc starting position has a large shrinkage amount, which provides a method for accurately correcting dimensional deformation for the welding of the safe end of the connecting pipe, thereby effectively improving dimensional accuracy.

[0144] Alternatively, as Figure 13 As shown, after returning to the preset second arc starting position and welding the welding groove 4 until the welding groove 4 is fully welded, the method further includes:

[0145] S910: Measure the gap size of the annular gap 5 to obtain a third size data set;

[0146] S920: Calculating a position error based on the third size data set;

[0147] S930: Determine whether the position error is less than a preset second error threshold;

[0148] S940: If the position error is less than the second error threshold, the welding of the safety end of the pipe is evaluated as qualified;

[0149] S950: Rotate the nut 14 of the anti-deformation tool 1 for welding the safety end of the pipe according to a preset rotation direction to remove the anti-deformation tool 1 for welding the safety end of the pipe.

[0150] In one embodiment, after the welding groove 4 is fully welded, the gap size of the annular gap 5 is measured again to obtain a third size data group. Based on the third size data group, combined with the size parameters of the pipe safety end and the installation position of the anti-deformation tool 1 for welding the pipe safety end, the position error between the pipe component 2 and the inner liner pipe 31 can be calculated, and it is determined whether the position error is less than a preset second error threshold, wherein the second error threshold can be designed according to the actual dimensional accuracy requirements; if it is less than, it means that the dimensional deformation of the pipe safety end after welding is within the qualified range, and the welding of the pipe safety end is determined to be qualified; then rotate the nut 14 in the preset rotation direction, for example, rotate the nut 14 counterclockwise to reduce the relative displacement of the first adjustment block 12 and the second adjustment block 13, thereby reducing the size of the anti-deformation tool 1 for welding the pipe safety end in the thickness direction, thereby facilitating the removal of the anti-deformation tool 1 for welding the pipe safety end.

[0151] In this embodiment, the size of the annular gap 5 is measured again after welding is completed to evaluate whether the dimensional accuracy of the safety end of the pipe after welding is qualified, thereby ensuring the quality of the welding product; if the quality is qualified, the welding operation is completed, and the anti-deformation tool 1 for welding the safety end of the pipe is adjusted to reduce its thickness direction size to facilitate its removal from the annular gap 5, thereby avoiding affecting the dimensional accuracy of the product due to the disassembly of the auxiliary tool. At the same time, the anti-deformation tool 1 for welding the safety end of the pipe is easy to disassemble and assemble, which is conducive to improving work efficiency.

[0152] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for welding a pipe safety end, characterized in that: Based on the anti-deformation tool for welding the safety end of the pipe, the anti-deformation tool for welding the safety end of the pipe comprises: a screw (11), a nut (14), a first adjustment block (12) and a second adjustment block (13); the screw (11) is fixedly connected to the first adjustment block (12), the second adjustment block (13) is abutted between the first adjustment block (12) and the nut (14), and the screw (11) and the nut (14) are connected by threaded fit; the first adjustment block (12) and the second adjustment block (13) are both provided with an inner cavity, and the diameter of the inner cavity is greater than the outer diameter of the screw (11); the first adjustment block (12) is also provided with a first inclined surface (121), and the second adjustment block (13) is also provided with a second inclined surface (131). The first inclined surface (121) abuts against the second inclined surface (131); the pipe safety end comprises a pipe component (2) and a safety end component (3), the outer surface of the pipe component (2) is provided with a first side slope (21); the safety end component (3) comprises an inner liner (31), the outer surface of the safety end component (3) is provided with a second side slope (32); when the nut (14) rotates, the second adjustment block (13) generates relative displacement with the first adjustment block (12) along the first inclined surface (121), and the first adjustment block (12) and the second adjustment block (13) are used to abut against the inner liner (31) of the safety end component (3) and the pipe component (2), respectively; the pipe safety end welding method comprises the following steps: The connecting pipe component (2) and the safety end component (3) are brought into contact with each other, and the first side slope surface (21) and the second side slope surface (32) form a welding groove (4); Performing initial welding on the welding groove (4) from a preset first arc starting position; The anti-deformation tool for welding the pipe safety end is installed in the annular gap (5) formed between the pipe component (2) and the inner liner (31), and the anti-deformation tool for welding the pipe safety end is used to support the annular gap (5); Measuring the gap size of the annular gap (5) to obtain a first size data set; Adjusting the anti-deformation tool for welding the pipe safety end based on the first size data group; Welding the welding groove (4) from a preset second arc starting position; Measuring the gap size of the annular gap (5) to obtain a second size data set; determining the second arc starting position for the next welding according to the second size data group; Returning to the step of welding the welding groove (4) from the preset second arc starting position until the welding groove (4) is fully welded.

2. The method for welding the safety end of a pipe according to claim 1, characterized in that: The first adjustment block (12) is further provided with a first contact surface (122) for abutting against the inner liner tube (31), and the second adjustment block (13) is further provided with a second contact surface (132) for abutting against the connecting pipe component (2), and the first contact surface (122) and the second contact surface (132) are both in the shape of circular arc surfaces.

3. The method for welding the safety end of a pipe according to claim 2, characterized in that: The top surface of the nut (14) is provided with a scale line (141), and the scale line (141) is provided with a corresponding displacement value (142), and the displacement value (142) is obtained based on the size of the anti-deformation tool for welding the safety end of the pipe; the bottom surface of the screw (11) is provided with a groove (111), and when the groove (111) corresponds to the scale line (141), it is used to indicate the displacement value (142) of the relative displacement.

4. The method for welding the safety end of a pipe according to claim 1, characterized in that: The measuring of the gap size of the annular gap (5) to obtain a first size data set includes: Measuring at least two preset measurement positions in the annular gap (5) using a deformation measurement tool, wherein the deformation measurement tool comprises a plurality of cylindrical rods having a dimensional accuracy greater than a preset first accuracy threshold, and the diameters of the cylindrical rods are arranged in a gradient; The diameter corresponding to the largest cylindrical rod that can be placed at the measurement position is used as the gap size; The measurement position and the corresponding gap size are recorded to obtain the first size data set.

5. The method for welding the safety end of a pipe according to claim 4, characterized in that: The cylindrical rod body includes a preset standard rod body; Before measuring at least two preset measurement positions in the annular gap (5) using a deformation measurement tool, the method further comprises: Determining whether the standard rod can be placed at the measurement position; If the standard rod cannot be placed at the measurement position, the cylindrical rod having a diameter smaller than that of the standard rod is selected to measure the annular gap (5); If the standard rod can be placed at the measurement position, the cylindrical rod having a diameter larger than that of the standard rod is selected to measure the measurement position.

6. The method for welding the safety end of a pipe according to claim 5, characterized in that: The step of adjusting the anti-deformation tool for welding the pipe safety end based on the first size data group includes: Calculating a position error between the connecting pipe component (2) and the inner liner pipe (31) based on the first size data group; Determining whether the position error is greater than a preset first error threshold; If the position error is greater than the first error threshold, an adjustment angle and an adjustment direction of the anti-deformation tool for welding the pipe safety end are determined based on the first size data group.

7. The method for welding the safety end of a pipe according to any one of claims 4 to 6, characterized in that: The second size data group includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; and determining the second arc starting position for the next welding according to the second size data group includes: Arrange the data sequence in descending order of the gap sizes; Taking the measurement position corresponding to the largest gap size in the data sequence as the maximum deformation position; A position on the welding groove (4) corresponding to the maximum deformation is selected as the second arc starting position.

8. The method for welding the safety end of a pipe according to claim 6, characterized in that: The second size data group includes a data sequence consisting of at least two measurement positions and corresponding gap sizes; and determining the second arc starting position for the next welding according to the second size data group includes: Calculating the position error based on the second size data set; Determining the offset direction of the liner pipe (31) based on the position error; The position of the welding groove (4) corresponding to the direction opposite to the offset direction is selected as the second arc starting position.

9. The method for welding the safety end of a pipe according to claim 8, characterized in that: After returning to the step of welding the welding groove (4) from the preset second arc starting position until the welding groove (4) is fully welded, the method further comprises: measuring the gap size of the annular gap (5) to obtain a third size data set; Calculating the position error based on the third size data set; Determining whether the position error is less than a preset second error threshold; If the position error is less than the second error threshold, the welding of the pipe safety end is evaluated as qualified; The nut (14) of the anti-deformation tool for welding the safety end of the pipe is rotated in a preset rotation direction to remove the anti-deformation tool for welding the safety end of the pipe.

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