Welding tool

Abstract

The utility model discloses a welding tool which comprises one or a plurality of variable-position heating components, wherein the one or the plurality of variable-position heating components are used for preheating or preserving heat of a welding pipe fitting and can rotate relative to the welding pipe fitting; the variable-position heating component comprises a heating component, a deformable mounting plate used for fixing the heating component and isolating the heating component from the welding piece, and a contact type thermocouple arranged between the heating component and the deformable mounting plate. The technical problems that in the welding process of the marine 15CrMo pipe, the argon arc welding efficiency is low, the minimum preheating temperature and the post-welding temperature are difficult to guarantee, and the welding operation condition safety is poor are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of welding, in particular to a welding tool. Background Art

[0002] With the rapid development of the shipbuilding industry, design and material selection are becoming increasingly diversified to meet the demands of diverse environments. 15CrMo, a heat-resistant steel, is increasingly used in ship piping, particularly exhaust pipes. However, due to the material's specific welding requirements, a series of problems arise during the welding process, impacting the overall shipbuilding cycle. This necessitates improvements to existing welding processes and research into new processes and technologies to improve welding conditions and increase production efficiency.

[0003] The traditional welding process for 15CrMo pipes uses manual argon arc welding. This method offers stable and reliable welding quality and beautiful welds, but it is generally only suitable for welding small-diameter, thin-walled pipes. The diameter of 15CrMo exhaust pipes for shipbuilding projects generally ranges from 700mm to 1200mm, with a wall thickness of 8mm to 12mm. These large dimensions present significant difficulties in welding, primarily due to the following issues:

[0004] 1) TIG welding has low efficiency. The construction period of a single weld is too long and the efficiency is low, which affects the construction rhythm of the entire project.

[0005] 2) The minimum preheating temperature is difficult to guarantee. 15CrMo requires a relatively high preheating temperature (generally not less than 120°C), resulting in slow argon arc welding speeds and difficulty maintaining the temperature during welding.

[0006] 3) Post-weld treatment temperature is difficult to maintain. Marine 15CrMo pipes generally use local post-weld heat treatment, with the holding temperature generally above 650°C. Due to the limitations of weldment size and construction environment, insulation is difficult to achieve.

[0007] 4) Poor welding conditions. During the welding process of 15CrMo pipes, a relatively high temperature (generally no less than 120°C) must be maintained throughout the entire joint. When using argon arc welding, the welder is in direct contact with the weldment, resulting in poor working conditions.

[0008] 5) Limited selection of welding materials. Argon arc welding wire that meets technical quality requirements generally lacks classification society certification or has incomplete certification. This requires batch-by-batch re-inspection of welding materials during use, impacting construction progress and increasing costs.

[0009] Therefore, in order to solve the above problems existing in the welding process of marine 15CrMo pipes, it is particularly important to carry out in-depth research on efficient welding tooling. Utility Model Content

[0010] The utility model provides a welding tool to overcome the above technical problems.

[0011] In order to achieve the above purpose, the technical solution of the utility model is:

[0012] A welding tool, comprising:

[0013] One or more positionable heating members that preheat or keep the welded pipes warm and are capable of rotating relative to the welded pipes;

[0014] The positionable heating component includes a heating component, a deformable mounting plate for fixing the heating component and isolating the heating component from a welding piece, and a contact thermocouple arranged between the heating component and the deformable mounting plate.

[0015] Furthermore, the variable position heating component is further provided with a connector for connecting a plurality of variable position heating components;

[0016] The connecting piece includes a metal round rod and a plurality of connecting hooks of different lengths;

[0017] One end of the deformable mounting plate is provided with a connecting hole structure, one end of the connecting hook is connected to the connecting hole structure, and the other end of the connecting hook is connected to the connecting hole structure provided on the adjacent deformable mounting plate;

[0018] The metal round rod is used to fix each connecting hook.

[0019] Furthermore, both ends of the connecting hook are provided with arc structures of the same shape and opposite bending directions;

[0020] The arc structure at one end of the connecting hook is connected to the connecting hole structure;

[0021] The arc structure at the other end of the connecting hook is clamped with the metal round rod.

[0022] Furthermore, the diameter of the metal round rod is the same as the diameter of the circle where the inner wall of the arc structure is located.

[0023] Furthermore, the contact thermocouple is located in the middle of the connecting end surface between the heating component and the deformable mounting plate.

[0024] Furthermore, the heating component adopts a flexible ceramic resistance heating sheet.

[0025] Furthermore, the deformable mounting plate is made of flexible iron sheet.

[0026] Furthermore, the connecting hooks are symmetrically arranged at both ends of the deformable mounting plate, and the number of connections at each end is at least two.

[0027] Furthermore, the connecting hook is made of No. 10 iron wire.

[0028] Compared with the prior art, the welding tool provided by the present invention has the following beneficial effects:

[0029] 1) High welding efficiency: The welded pipe is preheated or kept warm by the variable heating component, which can rotate relative to the welded pipe to quickly move the welding position of the welded pipe, thereby improving the efficiency of the welding itself and shortening the preparation and processing time outside of welding. The overall welding efficiency can be greatly improved.

[0030] 2) Stable and reliable weld performance: The overall heating and insulation temperature control method is adopted throughout the entire welding process. The welded pipes are preheated and post-heated through variable heating components, thereby achieving stable temperature control. The temperature of each part of the weld bead of the welded pipe is uniform and the temperature difference is small, which can ensure the stability and reliability of the performance of the entire weld.

[0031] 3) Improved welding operation safety: When using carbon dioxide gas shielded welding instead of tungsten inert gas welding, the welder's body does not need to come into direct contact with the high-temperature weldment through the deformable mounting plate, which improves the safety of welding operation conditions to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic top view of the structure of the welding tool of the present invention;

[0034] Figure 2 This is a front cross-sectional view of the structure of the welding tool in this embodiment;

[0035] Figure 3 This is a structural diagram of the connecting hook in this embodiment;

[0036] Figure 4 This is a schematic diagram of preheating the entire pipe before welding the welded pipe fitting in this embodiment;

[0037] Figure 5 This is a schematic diagram of the welded pipe after the variable position heating component in the welding zone is removed;

[0038] Figure 6 Schematic diagram of zoned welding of welded pipe fittings in this embodiment;

[0039] Figure 7 Schematic diagram of the rotation position of the welding pipe and the variable position heating component in this embodiment.

[0040] In the figure: 1. Variable position heating component; 11. Heating component; 12. Deformable mounting plate; 121. Connection hole structure; 13. Contact thermocouple; 14. Connecting piece; 141. Metal round rod; 142. Connecting hook; A. Welding pipe; B. Area to be welded; C. Welding completed area. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0042] This embodiment provides a welding tool, such as Figures 1 to 2 Shown, including:

[0043] One or more variable position heating components 1 are used to preheat or keep the welded pipe fittings warm and to rotate relative to the welded pipe fittings. The variable position heating components 1 include a heating component 11, a deformable mounting plate 12 for fixing the heating component 11 and isolating the heating component 11 from the welded part, and a contact thermocouple 13 arranged between the heating component 11 and the deformable mounting plate 12.

[0044] Specifically, the heating element 11 in this embodiment utilizes a flexible ceramic resistance heating sheet. The deformable mounting plate 12 utilizes flexible iron sheeting, which is a thin sheeting selected as needed for the flexible ceramic resistance heating sheet. The thin sheeting is 50 mm longer and 50 mm wider than the resistance heating sheet, respectively. While its thickness does not affect heat transfer and allows for flexible bending, it also possesses sufficient strength to easily wrap around the pipe to be welded. The contact thermocouple 13 is located midway between the connecting end faces of the heating element 11 and the deformable mounting plate 12. Specifically, the contact thermocouple is an accessory component of the electric heating device (temperature controller) and can be used directly for measuring and providing feedback on the heating temperature.

[0045] In a specific embodiment, the variable position heating component 1 is further provided with a connector 14 for connecting multiple variable position heating components 1; the connector 14 includes a metal round rod 141 and a plurality of connecting hooks 142 of different lengths; one end of the deformable mounting plate 12 is provided with a connecting hole structure 121, specifically, the connecting hole structure 121 is a round hole, and one end of the connecting hook 142 is connected to the connecting hole structure 121, and the other end of the connecting hook 142 is connected to the connecting hole structure 121 provided on the adjacent deformable mounting plate 12; the metal round rod 141 is used to fix each connecting hook 142. Specifically, the metal round rod in this embodiment has a diameter of 5 mm and a length slightly larger than the width of the thin iron sheet, and is used to fix the thin iron sheet to the connecting hook 142.

[0046] like Figure 3 As shown, the two ends of the connecting hook 142 are provided with arc structures of the same shape and opposite bending directions; the arc structure at one end of the connecting hook 142 is connected to the connecting hole structure 121; the arc structure at the other end of the connecting hook 142 is clamped to the metal round rod 141, and the diameter of the metal round rod 141 is the same as the diameter of the circle on which the inner wall of the arc structure is located. The connecting hook 142 and the connecting hole structure 121 are used to connect two adjacent groups of variable position heating components 1. The connecting hooks 142 of different lengths are made of No. 10 iron wire and can be used to adjust the length of the variable position heating component 1 when multiple resistance heating plates are used to connect welding pipes of different diameters, thereby improving the applicability to welding pipes.

[0047] In a specific embodiment, the connecting hooks 142 are symmetrically arranged at both ends of the deformable mounting plate 12, with at least two connected hooks at each end. The metal round rods 141 are engaged with the connecting hooks 142 to prevent movement of the connecting hooks 142 during use. This ensures that each positionable heating member 1 is centered when rotated to the desired position, thereby preventing problems such as preheating the welded pipe or insufficient heat preservation of the weld after welding, which could affect welding quality.

[0048] The design principle and advantages of the variable position heating member in this embodiment are as follows:

[0049] Conventional resistance heaters currently come into direct contact with the weldment, with thermocouples placed between them. To ensure timely and accurate temperature measurement and feedback from the thermocouples, the relative position of the heater and weldment must remain fixed. Furthermore, the heater's structural composition and material properties create significant friction between them, making movement difficult.

[0050] This embodiment designs a variable position heating component, that is, the flexible ceramic resistance heating sheet is isolated from the weldment (welded pipe) by a thin iron sheet, thereby reducing the friction between the heating sheet and the weldment, so that the resistance heating sheet can be rotated and displaced at any time as needed during use. The thermocouple is placed between the flexible ceramic resistance heating sheet and the thin iron sheet to form a whole, which is used as a variable position heating component. In the process of relative rotation between the variable position heating component and the weldment, the timeliness and accuracy of the thermocouple temperature measurement and temperature feedback will not be affected. The thin iron sheet of the variable position heating component in this embodiment is relatively thin and is in close contact with the weldment, so the heat loss is small and does not affect the normal heat transfer. At the same time, temperature compensation can be achieved by increasing the preset heating temperature by 10~20℃.

[0051] This embodiment also includes a method for using the variable position heating component:

[0052] Before starting formal heating, the variable position heating component is debugged. The debugging process can be debugged according to the needs through existing technology, and the debugging software and program involved are not the invention points of this application, so they will not be described in detail here. The contact thermocouple is fixed in the interlayer between the electric heating plate and the thin iron sheet, such as Figures 4 to 7 As shown, the usage steps are as follows:

[0053] Step 1: After the welding pipe fittings are assembled, select an appropriate number of variable position resistance heating plates according to the pipe diameter to preheat the entire pipe, that is, connect two or more variable position heating components end to end through connecting hooks and connecting hole structures. After connection, if the heating plate cannot fit tightly with the outer wall of the pipe due to the length, the length can be adjusted through connecting hooks of different sizes; if necessary, the overall length of the heating plate can be adjusted by tying a knot in the middle of the connecting hook.

[0054] Step 2. After the overall preheating temperature of the weldment reaches the preset temperature through the variable position heating component, there is no need to remove the variable position heating component as a whole. By using a set of connecting hooks with the same length as a single variable position heating component, the variable position heating component at the position to be welded is replaced, and the variable position heating components at other positions are retained to continue heating and keeping warm the other positions of the weldment.

[0055] Step 3: Complete the welding of the weld of the current area to be welded (i.e. the area of ​​the variable position heating component replaced by the connecting hook).

[0056] Step 4: After the weld of the current area is completed, the variable position heating element can be rotated relative to the workpiece by manually pulling the connecting hook to change the relative position between the variable position heating element and the workpiece. After the position is properly adjusted, the next area to be welded is welded, and the completed weld bead is kept warm until the welds of all the areas to be welded are completed.

[0057] Step 5: After all welds are completed, the replaced variable position heating component is reinstalled to heat and insulate the entire weld.

[0058] This embodiment also includes the optimization process of welding process parameters:

[0059] The diameter of marine 15CrMo pipes generally ranges from 700mm to 1200mm, with a wall thickness of 8mm to 12mm. Traditionally, GTAW (gas tungsten arc welding) is used, with a welding current of 120-140A, a voltage of 11-14V, a speed of 7-15cm / min, and a post-weld heat treatment temperature of 650-680°C for 15-20 minutes. We attempted to optimize the process parameters in the following areas:

[0060] The carbon dioxide gas shielded welding process is used to fill the cover surface, with a current of 170~200A, a voltage of 23~25V, and a speed of 15~20cm / min.

[0061] Post-heating is used instead of post-weld heat treatment to reduce the insulation temperature and extend the insulation time. The post-heating temperature is 300~350℃ and the insulation time is 2 hours.

[0062] This embodiment also includes welding test:

[0063] After determining the heating method, welding process, current and voltage parameters, post-weld holding temperature and time, an on-site welding test was carried out:

[0064] The variable position heating member in this embodiment is used for heating and heat preservation, and the preheating and heat preservation temperature is 120-130°C, which has a good heat preservation effect during the entire welding process;

[0065] After the welding is completed using the welding process method of tungsten inert gas welding for base laying and carbon dioxide gas shielded welding for filling and covering, the weld appearance is well formed.

[0066] After welding, 100% MT+100% UT inspection was carried out and no welding defects were found.

[0067] In this embodiment, various physical and chemical tests were carried out after welding the pipe fittings, and the test results were good. The relevant test items and results are shown in Tables 1 and 2 below:

[0068]

[0069]

[0070] This embodiment also includes a comparative experiment on the welding efficiency of welded pipe fittings:

[0071] The use of variable position heating components for preheating, heat preservation, post-heating and heat treatment of pipe fittings avoids repeated disassembly and assembly of heating equipment, saving 0.5 hours of operation time for each weld.

[0072] Compared with pure tungsten inert gas welding, the welding process of tungsten inert gas welding for base welding and carbon dioxide gas shielded welding for filling and capping can improve the welding efficiency of 8mm wall thickness pipe by 68.2% and 12mm wall thickness pipe by 74.5%. The improvement in welding efficiency is more obvious as the pipe wall thickness increases. The efficiency comparison is shown in Table 3:

[0073]

[0074] Among them: FCAW - flux-cored carbon dioxide gas shielded welding;

[0075] GTAW – Gas Tungsten Arc Welding;

[0076] Using post-weld heat treatment instead of post-weld heat treatment can save 1.25 hours of heating and holding time for each weld, and the holding temperature is relatively low, easy to operate and the temperature is stable. The comparison of heating and holding time is shown in Table 4:

[0077]

[0078] In summary, using the high-efficiency welding tooling to weld marine 15CrMo pipes can increase welding efficiency by over 68.2%, saving an additional 0.5 hours of equipment disassembly and assembly time and 1.25 hours of heating and holding time per weld. The application of the welding tooling and the high-efficiency welding process for marine 15CrMo pipes has significantly improved welding efficiency.

[0079] In summary, the use of the welding tool in this embodiment has the following beneficial effects:

[0080] 1) High welding efficiency: The welded pipe is preheated or kept warm by the variable heating component, which can rotate relative to the welded pipe to quickly move the welding position of the welded pipe, thereby improving the efficiency of the welding itself and shortening the preparation and processing time outside of welding. The overall welding efficiency can be greatly improved.

[0081] 2) Stable and reliable weld performance: The overall heating and insulation temperature control method is adopted throughout the entire welding process. The welded pipes are preheated and post-heated through variable heating components, thereby achieving stable temperature control. The temperature of each part of the weld bead of the welded pipe is uniform and the temperature difference is small, which can ensure the stability and reliability of the performance of the entire weld.

[0082] 3) Improved welding operation safety: When using carbon dioxide gas shielded welding instead of tungsten inert gas welding, the welder's body does not need to come into direct contact with the high-temperature weldment through the deformable mounting plate, which improves the safety of welding operation conditions to a certain extent.

[0083] 4) Increase the options for alternative welding materials: The new process method uses carbon dioxide gas shielded welding instead of tungsten inert gas welding. There are fewer types of argon arc welding wires certified by classification societies, but it is relatively easy to select flux-cored gas shielded welding wire that meets the requirements, which expands the alternative options for welding materials.

[0084] 5) Can be promoted and applied horizontally: Although the new process method was tested based on the welding of marine 15CrMo pipes, it is also of reference value for other materials with the same or similar welding requirements and can be promoted and applied horizontally.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A welding tool, characterized in that: include: One or more positionable heating members (1) that are capable of preheating or heat-insulating the welded pipe and are capable of rotating relative to the welded pipe; The variable position heating component (1) comprises a heating component (11), a deformable mounting plate (12) for fixing the heating component (11) and isolating the heating component (11) from a welding part, and a contact thermocouple (13) arranged between the heating component (11) and the deformable mounting plate (12).

2. A welding tool according to claim 1, characterized in that: The variable position heating component (1) is further provided with a connecting piece (14) for connecting a plurality of variable position heating components (1); The connecting member (14) comprises a metal round rod (141) and a plurality of connecting hooks (142) of different lengths; One end of the deformable mounting plate (12) is provided with a connection hole structure (121), one end of a connection hook (142) is connected to the connection hole structure (121), and the other end of the connection hook (142) is connected to a connection hole structure (121) provided on an adjacent deformable mounting plate (12); The metal round rod (141) is used to fix each connecting hook (142).

3. A welding tool according to claim 2, characterized in that: Both ends of the connecting hook (142) are provided with arc structures of the same shape and opposite bending directions; The arc-shaped structure at one end of the connecting hook (142) is connected to the connecting hole structure (121); The arc-shaped structure at the other end of the connecting hook (142) is clamped with the metal round rod (141).

4. A welding tool according to claim 3, characterized in that: The diameter of the metal round rod (141) is the same as the diameter of the circle where the inner wall of the arc-shaped structure is located.

5. A welding tool according to claim 1, characterized in that: The contact thermocouple (13) is located in the middle of the connecting end surface between the heating component (11) and the deformable mounting plate (12).

6. A welding tool according to claim 1, characterized in that: The heating component (11) adopts a flexible ceramic resistance heating sheet.

7. A welding tool according to claim 1, characterized in that: The deformable mounting plate (12) is made of flexible iron sheet.

8. A welding tool according to claim 2, characterized in that: The connection hooks (142) are symmetrically arranged at two ends of the deformable mounting plate (12), and the number of connections at each end is at least two.

9. A welding tool according to claim 8, characterized in that: The material of the connecting hook (142) is No. 10 iron wire.

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