A distortion prevention welding method for limiting transverse shrinkage of a weld

Abstract

This invention discloses a method for preventing deformation during weld seam lateral shrinkage. The method includes: assembling and positioning a first base material and a second base material to be welded; welding at least two anti-deformation fixtures at predetermined intervals along the length of the weld seam between the first and second base materials, wherein the bottom of each anti-deformation fixture has an arched structure, with its two ends welded to the first and second base materials respectively, and the arched structure corresponding to the weld seam; welding the bottom portion of the weld seam located under the anti-deformation fixtures, with a welding thickness of a first thickness, which is less than the total thickness of the weld seam; welding the bottom portion of the weld seam located between adjacent anti-deformation fixtures, with a welding thickness of a second thickness, which is less than the total thickness of the weld seam; removing the anti-deformation fixtures; and completing the welding of the remaining weld seam thickness. Its advantage is that this method can suppress lateral shrinkage deformation during the welding of large, thick-walled austenitic stainless steel weld seams.

Description

Technical Field

[0001] This invention relates to the field of welding deformation control technology for large thick-walled austenitic stainless steel components, specifically to an anti-deformation welding method that limits the lateral shrinkage of the weld, applicable to the precision welding and manufacturing of enclosed pressure-bearing structures such as coil boxes for nuclear fusion devices. Background Technology

[0002] Large, thick-walled austenitic stainless steel components, such as those for nuclear fusion devices, pressure vessels, large storage tanks, and special ship structures, are widely used in high-end equipment manufacturing due to their excellent high-temperature strength, corrosion resistance, and low-temperature toughness. However, austenitic stainless steel inherently possesses low thermal conductivity and a high coefficient of linear expansion, resulting in extremely uneven temperature field distribution during welding, leading to high concentration of thermal stress and particularly prominent welding deformation problems. Existing welding deformation control technologies primarily focus on angular deformation and wave deformation, with limited research on targeted control of weld transverse shrinkage. For weld transverse shrinkage, a key deformation form that directly affects the overall dimensional accuracy of components, current conventional engineering solutions mainly rely on reserving machining allowances in the base material. After welding, excess material is removed through subsequent machining to compensate for dimensional deviations caused by transverse shrinkage. However, this method cannot meet the requirements for welding in closed structures or scenarios where machining compensation is not possible.

[0003] Taking the manufacturing of the fusion reactor coil box in the "artificial sun" nuclear fusion device as an example, this technical challenge is particularly prominent. The fusion reactor coil box is a large, irregularly shaped forged and welded structure, with external dimensions of approximately 18m × 12m. The main body is made of austenitic stainless steel 316LN, with a maximum weld thickness of 380mm. Due to the low thermal conductivity and high coefficient of linear expansion of austenitic stainless steel, significant deformation is easily generated during the welding process. In addition, the coil box is an irregularly shaped, closed structure, forming a closed space after welding. The internal dimensions cannot be corrected by machining, making the control of welding deformation extremely difficult (especially the lateral shrinkage of the weld), which is the core technical challenge in the manufacturing of the coil box. However, traditional methods of leaving allowances and machining compensation cannot meet the requirements of such closed structures. Therefore, improvements to the welding method are needed.

[0004] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0005] Based on the aforementioned technical problems, the purpose of this invention is to provide a deformation-resistant welding method for limiting the transverse shrinkage of welds. This method focuses on solving the technical problem of difficulty in controlling the transverse shrinkage of welds in scenarios such as closed structures and situations where machining compensation is not possible. This method combines anti-deformation tooling with a segmented and layered welding sequence, which can achieve precise control of the transverse shrinkage of large thick-walled austenitic stainless steel welds.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A deformation-preventing welding method for limiting transverse shrinkage of weld seams, comprising: Assemble and position the first and second base materials to be welded; At least two anti-deformation fixtures are welded at predetermined intervals along the length of the weld between the first base material and the second base material. The bottom of the anti-deformation fixture is an arched structure, and the two ends of the bottom of the arched structure are respectively welded to the first base material and the second base material. The arched structure is set corresponding to the weld. Welding is performed on the bottom portion of the weld located under the anti-deformation fixture, and the weld thickness is a first thickness, which is less than the total thickness of the weld. Welding is performed on the bottom portion of the weld seam located between adjacent anti-deformation fixtures, and the weld thickness is the second thickness, which is less than the total thickness of the weld seam. Remove the anti-deformation tooling; Complete the welding of the remaining thickness of the weld seam.

[0007] Optionally, before welding the bottom portion of the weld located under the anti-deformation fixture, a root pass weld can be performed along the entire length of the weld.

[0008] Optionally, after welding the bottom part of the weld located under the anti-deformation fixture, the welded part can be ground.

[0009] Optionally, after welding the bottom portion of the weld located between adjacent anti-deformation fixtures, the welded portion can be ground.

[0010] Optionally, the first base material and / or the second base material is a thick-walled austenitic stainless steel component, and the weld between the first base material and the second base material has a cross-section that is narrow at the bottom and wide at the top along the first direction. The misalignment of the weld is in the range of 0~2mm, and the bevel gap is in the range of 2mm~4mm.

[0011] Optionally, the spacing between adjacent anti-deformation fixtures along the length of the weld can range from 500mm to 700mm. Alternatively, the spacing between adjacent anti-deformation fixtures along the length of the weld is 600mm.

[0012] Optionally, the first thickness is the same as the second thickness.

[0013] Optionally, the first thickness is 50% to 70% of the total thickness of the weld, or the first thickness is 60% of the total thickness of the weld; The second thickness is 50% to 70% of the total thickness of the weld, or the second thickness is 60% of the total thickness of the weld.

[0014] Optionally, the anti-deformation tooling is a Lamer tooling.

[0015] Optionally, the anti-deformation tooling has a thickness of 40mm, a height of 100mm, a length of 200mm, and a bottom arched structure radius of 50mm.

[0016] Compared with the prior art, the present invention has the following advantages: In the anti-deformation welding method for limiting the lateral shrinkage of welds of the present invention, the anti-deformation tooling is combined with the segmented and layered welding sequence to form a reliable welding method with graded constraints, thereby realizing the stable transfer of rigid constraints and achieving precise control of the lateral shrinkage of large thick-walled austenitic stainless steel welds. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings in the following description are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of a deformation-preventing welding method for limiting lateral shrinkage of welds according to the present invention; Figure 2 This is a cross-sectional schematic diagram of an anti-deformation tooling and weld seam along the first direction according to the present invention; Figure 3 This is a cross-sectional schematic diagram of an anti-deformation tooling and weld seam of the present invention along a second direction, wherein the second direction is perpendicular to the first direction. Figure 4 This is a cross-sectional schematic diagram along the first direction during the assembly and welding of a fusion reactor coil box according to the present invention; Figure 5 This is a schematic diagram of the cover plate side during the assembly and welding of a fusion reactor coil box according to the present invention. Detailed Implementation

[0018] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the anti-deformation welding method for limiting transverse shrinkage of welds proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0019] As discussed above, existing technologies struggle to precisely control the lateral shrinkage of welds in large, thick-walled stainless steel enclosed components. Therefore, there is an urgent need for a deformation-preventing method that can effectively limit lateral shrinkage and is suitable for welding enclosed structures. To address this, this invention provides a deformation-preventing welding method to limit lateral shrinkage during welding of the first base material 1 and the second base material 2 (avoiding the shortening of the distance between them, i.e., the base materials on both sides of the weld 3 moving towards the center) (see [link to relevant documentation]). Figure 2 This method employs a combination control scheme of anti-deformation fixture 4 and segmented layered welding sequence. Anti-deformation fixture 4 with an arched bottom structure is welded to the surfaces of the first base material 1 and the second base material 2 to facilitate welding of the first weld 31 below the anti-deformation fixture 4. Multiple sets of anti-deformation fixtures 4 are arranged at intervals along the length of the long weld 3. Through the rigid constraint of the anti-deformation fixture 4 and the synergistic effect of the segmented welding sequence, the transverse shrinkage deformation of the weld 3 is suppressed throughout the entire process.

[0020] like Figures 1 to 3 The diagram shows a method for preventing deformation welding by limiting the lateral shrinkage of weld 3 according to the present invention and its principle. In this method, weld 3 includes a first weld 31, a second weld 32 and a third weld 33. The first weld 31 is the bottom part of weld 3 located under the anti-deformation fixture 4, the second weld 32 is the bottom part of weld 3 located between adjacent anti-deformation fixtures 4, and the third weld 33 is the part of weld 3 above the first weld 31 and the second weld 32.

[0021] Specifically, the anti-deformation welding method for limiting the lateral shrinkage of weld 3 according to the present invention includes: S1, assembling and positioning the first base material 1 and the second base material 2 to be welded; S2, welding at least two anti-deformation fixtures 4 at predetermined intervals along the length direction of weld 3 between the first base material 1 and the second base material 2, wherein the bottom of the anti-deformation fixture 4 is an arched structure, and the two ends of the bottom of the arched structure are respectively welded to the first base material 1 and the second base material 2, and the arched structure is set corresponding to weld 3; S3, welding the bottom part of weld 3 located under the anti-deformation fixture 4, i.e., the first weld 31, from bottom to top, with a welding thickness of a first thickness, which is less than the total thickness of weld 3; S4, welding the bottom part of weld 3 located between adjacent anti-deformation fixtures 4, i.e., the second weld 32, from bottom to top, with a welding thickness of a second thickness, which is less than the total thickness of weld 3; S5, removing the anti-deformation fixtures 4; S6, completing the welding of the remaining thickness of weld 3, i.e., the third weld 33.

[0022] As described above, in the anti-deformation welding method for limiting the lateral shrinkage of weld 3 of the present invention, a reliable method of graded constraint is adopted. In the initial stage of welding, the external anti-deformation fixture 4 (e.g., a Lamar fixture) provides rigid constraint, and then the already welded weld 3 (first weld 31 and second weld 32) bears the constraint force itself. The anti-deformation fixture 4 is removed only after the welded part inside the weld 3 has sufficient strength, thus achieving a smooth transfer of constraint force and ensuring the stability of lateral deformation control. At the same time, this method also achieves multiple deformation synergistic control. The anti-deformation fixture 4 not only limits lateral shrinkage but also limits angular deformation, achieving multiple deformation control effects with a single fixture deployment. In addition, this method can precisely control lateral shrinkage. It is specifically designed for the lateral shrinkage of weld 3 in thick plates and closed structures, making full use of the characteristic that welding deformation mainly occurs in the initial stage and is not easily deformed in the later stage as the weld thickness increases. Through the synergistic effect of the rigid constraint of the anti-deformation fixture 4 and the segmented welding sequence, lateral shrinkage is suppressed throughout the process, effectively solving the problem that conventional techniques cannot accurately control this type of deformation.

[0023] Furthermore, this method boasts advantages such as simple and feasible process and strong compatibility. It achieves the anti-deformation goal simply by using anti-deformation tooling 4, such as conventional Lamer tooling 7, and optimizing the welding sequence. No specialized or complex equipment is required, and it is applicable to common welding processes such as manual arc welding and manual TIG welding, demonstrating excellent versatility. In addition, this method is particularly suitable for enclosed structures. Since the anti-deformation tooling 4 is positioned outside the base material, there is no need to install tooling inside the enclosed structure during the welding process, and no dimensional correction through machining is required after welding. This fundamentally meets the stringent manufacturing requirements of large enclosed components such as fusion reactor coil boxes.

[0024] On the other hand, compared to existing welding methods that focus on controlling angular deformation, the anti-deformation welding method of this invention directly addresses the difficulties by precisely suppressing the most difficult-to-control lateral shrinkage deformation during welding, thus effectively ensuring welding quality. Furthermore, in terms of application scenarios, existing welding methods are mostly applied to membrane frame structures, while the anti-deformation welding method of this invention is suitable for thick-walled pressure components. Traditional thick-walled components typically rely on increasing the machining allowance of the base material to compensate for dimensional deficiencies caused by lateral shrinkage. However, in many demanding working conditions where increased allowances are not possible (such as closed structures where post-weld machining is not feasible), traditional solutions are ineffective, and this invention fills this gap. Moreover, existing welding methods mainly employ methods such as pre-reserved anti-deformation, tooling constraints, low-heat welding, and post-weld stress relief treatment. This invention, addressing the limitations of pre-reserved anti-deformation and post-weld stress relief treatment in certain working conditions, adopts a collaborative control strategy of "external anti-deformation tooling constraints + adjusting the welding sequence to generate internal self-constraint," effectively replacing traditional methods and achieving fundamental control over lateral shrinkage deformation.

[0025] The following example uses the welding of the fusion reactor coil box assembly cover plate 6 as an example (see [link]). Figure 4 and Figure 5 This section describes the anti-deformation welding method for limiting the lateral shrinkage of weld 3 according to the present invention. The assembly process of the fusion reactor coil box is as follows: first, the coil winding is assembled into the U-shaped box 5, and then the cover plate 6 is welded to form a closed inner cavity. This process has strict requirements on the assembly clearance accuracy between the box 5 and the winding, and the closed space formed after welding cannot be corrected by machining. Therefore, the lateral shrinkage of weld 3 during the welding process of cover plate 6 must be strictly controlled; however, conventional allowance compensation schemes cannot meet the requirements.

[0026] like Figure 4 and Figure 5 The diagram shows a schematic of the assembly welding of a fusion reactor coil box using the anti-deformation welding method for limiting the lateral shrinkage of the weld seam 3 according to one embodiment of the present invention. In this embodiment, the thick-walled materials of the cover plate 6 and the box body 5 are both 316LN austenitic stainless steel, and the welding process is manual argon arc welding. The cross-section of the weld seam 3 between the cover plate 6 and the box body 5 is trapezoidal, narrow at the bottom and wide at the top, with a thickness of 100 mm and a length of 18 meters. Since the inner cavity of the box body 5 is closed, it is impossible to set the anti-deformation tooling 4 inside, and it is also impossible to machine the inner cavity after welding. In order to ensure the uniformity of the inner cavity dimensions, it is necessary to strictly control the shrinkage and deformation of the weld seam 3. Therefore, the following anti-deformation scheme is adopted: T1. Workpiece Assembly: Assemble and position the box body 5 and cover plate 6, strictly controlling the misalignment and bevel gap to meet welding process requirements. Misalignment refers to the height difference of the bevel's blunt edge after assembly; controlling the misalignment is primarily to ensure the quality of the root weld 3. In practical applications, when assembling the box body 5 and cover plate 6, to ensure the quality of the root pass weld, the misalignment range is controlled to 0~2mm, and the bevel gap range is 2mm~4mm.

[0027] T2. Welding anti-deformation fixture 4. In this embodiment, the anti-deformation fixture 4 is a Lamb fixture 7, which has a thickness of 40mm, a height of 100mm, a length of 200mm, a bottom arched structure radius of 50mm, and a corner weld height of approximately 20mm. In this embodiment, a Lamb fixture 7 is welded every 600mm along the length of the box body 5. The Lamb fixtures 7 are evenly distributed along the length of the weld seam 3, that is, the spacing between adjacent Lamb fixtures 7 along the length of the weld seam 3 is 600mm. The bottom two ends of the arched structure of the bottom of the Lamb fixture 7 are welded to the box body 5 and the cover plate 6, respectively. The arched structure can ensure the welding space below.

[0028] Before welding the bottom portion of weld 3, i.e., the first weld 31, located under the anti-deformation fixture 4, a full-length root pass welding is performed along the length of weld 3. This method not only maintains the bevel gap at 2mm~4mm, ensuring the welding quality at the root of weld 3, but also unifies the initial state of the entire weld 3, ensuring consistency between the restraint state and thermal shrinkage response along the entire length. This provides a unified and reliable stress reference for the subsequent synergistic effect of the anti-deformation fixture 4 and the segmented and layered welding sequence, avoiding uneven stress distribution or asynchronous shrinkage deformation caused by local state differences, thereby improving the accuracy and stability of overall lateral shrinkage control.

[0029] T4. Weld the bottom area of ​​the weld 3 below each of the Lamer fixtures 7, that is, weld the first weld 31 of each first thickness (see [link]). Figure 3Prioritizing welding the bottom region of weld 3 below the Rammer fixture 7 maximizes the rigid constraint effectiveness of the external Rammer fixture 7. Since the first weld 31 is directly below the Rammer fixture 7, the constraint force of the Rammer fixture 7 on the base material is most direct and strongest at this time. It can forcibly restrict the base material in this area to move towards the center in the initial stage when the weld 3 is most prone to lateral shrinkage, that is, to use the rigid constraint of the Rammer fixture 7 to limit lateral shrinkage. At the same time, the welded part at the first weld 31 can first establish a rigid skeleton inside the weld 3 under the protection of the Rammer fixture 7. When the first weld 31 is welded to the set first thickness, it has sufficient rigidity and strength, which is equivalent to implanting a hard skeleton inside the weld 3, transforming it from a protected weak part into a stress-bearing structure that can actively resist shrinkage. Furthermore, this method lays a reliable foundation for the smooth transfer of subsequent rigid constraint forces. When welding the second weld 32, the first weld 31 can work together with the Lamar tool 7 to resist the shrinkage force, realizing a gradual and smooth transition of constraint dominance from the external Lamar tool 7 to the internal weld 3. This avoids deformation rebound caused by the sudden loss of constraint force, thereby ensuring the stability and reliability of the transverse shrinkage control throughout the entire process.

[0030] In this embodiment, the controlled deformation range of each Lamer tool 7 is approximately 150mm on each side, with a total length of approximately 300mm. Therefore, the length of the first weld 31 is approximately 150mm on each side of the Lamer tool 7. Based on this method, the effective restraint range of a single Lamer tool 7 can be precisely matched, ensuring that the rigid restraint force of the Lamer tool 7 is efficiently transmitted and transformed into the rigidity of the internal weld 3. This avoids the dispersion of restraint force or the failure to lock the base material locally due to insufficient welding length, and also prevents deformation caused by insufficient restraint when welding beyond the effective restraint range. Thus, seamless connection and precise conversion of the external tooling and the internal skeleton in terms of spatial restraint are achieved.

[0031] The first thickness of the first weld 31 is 60% of the total thickness of weld 3, i.e., 60mm. Based on this method, it can be ensured that a sufficient internal rigid skeleton is formed at the first weld 31. Since welding deformation mainly occurs in the initial stage when the thickness of weld 3 is relatively thin, when the thickness of the welded part at the first weld 31 reaches 60% of the total thickness, it has accumulated sufficient strength and tensile stiffness. It transforms from a weak part that originally needed external ramming fixture 7 protection into a rigid skeleton that can resist lateral shrinkage force. If the thickness is too low, the rigidity will be insufficient and deformation rebound will easily occur after the ramming fixture 7 is removed. On the other hand, if the weld is directly filled, the heat input will be too large and it will easily cause greater residual stress and deformation accumulation.

[0032] T5. Weld 3 Finishing: After welding the bottom portion of weld 3, i.e., the first weld 31, located under the Ramer fixture 7, the welded portion of the first weld 31 is ground. In this embodiment, after the first weld 31 is welded, the welded portions of both ends of the weld 3 are ground until they are suitable for subsequent weld 3 welding, for example, forming a bevel that smoothly connects with the subsequent weld 3. Based on this method, not only can stress concentration and welding defect risks caused by geometrical abrupt changes be effectively eliminated, but also a good operating space and filling conditions are provided for the subsequent welding of the second weld 32, enabling the molten metal to fill the gap uniformly and solidly, ensuring a strong metallurgical bond and smooth appearance between the first weld 31 and the second weld 32.

[0033] Furthermore, in this invention, the first weld 31 and the second weld 32 are used to form an internal rigid skeleton to control the constraint force of the anti-deformation fixture 4. The grinding process ensures a smooth transition and seamless connection between the skeleton nodes, so that the entire bottom weld 3 can truly be integrated into a continuous and complete rigid whole. This avoids the interruption of constraint force transmission due to weak local connections, thereby ensuring that after the external anti-deformation fixture 4 is removed, the weld 3 itself can stably and continuously resist lateral shrinkage deformation.

[0034] T6. Weld the bottom area of ​​each weld 3 located in the middle area of ​​the adjacent Ramer tooling 7, that is, weld each second weld 32 of the second thickness (see [link]). Figure 3 After the second weld 32 is completed, the strength of the welded part of weld 3 is sufficient to resist lateral shrinkage. At this time, the control of the constraint force is smoothly transferred from the external anti-deformation fixture 4 to the internal weld 3 skeleton. Even if the anti-deformation fixture 4 is removed later, the welded part can still firmly hold the two parent materials on both sides, namely the cover plate 6 and the box body 5, to avoid stress release and deformation rebound caused by the sudden disappearance of the constraint.

[0035] In this embodiment, the length of the second weld 32 is approximately 300 mm, the same as the weld length of the first weld 31. Furthermore, in this embodiment, the second thickness is 60% of the total thickness of the weld 3, meaning the first and second thicknesses are the same. The surfaces of the first weld 31 and the second weld 32 are flush, allowing the rigidity of the welded portion (the welded portion of the first weld 31 and the second weld 32) to continue constraining shrinkage and achieve rigid constraint transfer. Based on this method, it can be ensured that the bottom layer weld formed by the first weld 31 and the second weld 32 forms a true "integral rigid skeleton," significantly improving the tensile and bending stiffness of the bottom layer weld. Simultaneously, this method also enables reliable and stable transfer of constraint force. In addition, since the sufficiently thick bottom layer weld has firmly anchored the base material, the thermal shrinkage force generated by subsequent filler welding will be offset by the rigidity of the integral rigid skeleton formed by the welded portion of the first weld 31 and the second weld 32, ensuring precise control of the lateral shrinkage of the weld 3. Therefore, the first weld 31 and the second weld 32 lay a solid foundation for the subsequent full welding of the remaining thickness.

[0036] T7. Weld Seam 3 Finishing: After welding the bottom part of weld seam 3, i.e., the second weld seam 32, located between adjacent anti-deformation fixtures 4, the welded part at the second weld seam 32 is ground. Based on this method, an ideal welding foundation can be created for the full welding of the remaining thickness (third weld seam 33) in the future, which helps to ensure the quality of the full welding. At the same time, this method also helps to maintain the reliability of the entire welded part of weld seam 3.

[0037] T8. Grind and remove the lama tool 7 to ensure that the surface of the base material, namely the cover plate 6 and the box body 5, is flat.

[0038] T9, Full Welding: Complete the welding of the remaining thickness of weld 3, i.e., the third weld 33 (see [link]). Figure 3 ), to achieve the final shape.

[0039] Actual measurements verified that after welding using the anti-deformation welding method of this invention, the lateral shrinkage of weld 3 is approximately 2mm, fully meeting the product's accuracy requirement of ≤4mm. Compared to the approximately 8mm lateral shrinkage without using the anti-deformation welding method of this invention, the anti-deformation welding method of this invention significantly reduces the lateral shrinkage, and welding deformation is significantly and effectively controlled.

[0040] It is understood that in practical applications, the anti-deformation tooling 4 is not limited to the aforementioned Lamer tooling 7, but can also be other components with sufficient rigidity. This invention does not limit this, as long as the corresponding function can be achieved. On the other hand, the spacing, first thickness, and second thickness of adjacent anti-deformation tooling 4 along the length of the weld 3 are not limited to the examples described above. In other embodiments, they can be other data or ranges, and this invention does not limit this. For example, in some embodiments, the spacing of adjacent anti-deformation tooling 4 along the length of the weld 3 ranges from 500mm to 700mm; and / or, the first thickness is 50% to 70% of the total thickness of the weld 3, and the second thickness is 50% to 70% of the total thickness of the weld 3. Furthermore, the cross-sectional shape of the weld 3 is not limited to the aforementioned inverted trapezoidal structure; it can also be a V-shaped structure, narrower at the bottom and wider at the top, to facilitate accurate welding with the welding torch.

[0041] In summary, the anti-deformation welding method for limiting the lateral shrinkage of weld 3 in this invention combines the anti-deformation fixture 4 with a segmented and layered welding sequence, enabling precise control of the lateral shrinkage of weld 3 in large, thick-walled austenitic stainless steel. This method is applicable to the anti-deformation welding of large, thick-walled austenitic stainless steel, focusing on solving the technical problem of difficult control of the lateral shrinkage of weld 3 in closed structures and scenarios where machining compensation is not possible. It can ensure the welding dimensional accuracy and assembly performance of key components such as fusion reactor coil boxes.

[0042] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for preventing deformation welding by limiting transverse shrinkage of the weld, characterized in that, Include: Assemble and position the first and second base materials to be welded; At least two anti-deformation fixtures are welded at predetermined intervals along the length of the weld between the first base material and the second base material. The bottom of the anti-deformation fixture is an arched structure, and the two ends of the bottom of the arched structure are respectively welded to the first base material and the second base material. The arched structure is set corresponding to the weld. Welding is performed on the bottom portion of the weld located under the anti-deformation fixture, and the weld thickness is a first thickness, which is less than the total thickness of the weld. Welding is performed on the bottom portion of the weld seam located between adjacent anti-deformation fixtures, and the weld thickness is the second thickness, which is less than the total thickness of the weld seam. Remove the anti-deformation tooling; Complete the welding of the remaining thickness of the weld seam.

2. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, Before welding the bottom part of the weld located under the anti-deformation fixture, perform root pass welding along the entire length of the weld.

3. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, After welding the bottom part of the weld located under the anti-deformation fixture, the welded part is ground.

4. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, After welding the bottom part of the weld between adjacent anti-deformation fixtures, the welded part is ground.

5. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The first base material and / or the second base material are thick-walled austenitic stainless steel components. The weld between the first base material and the second base material has a cross-section that is narrow at the bottom and wide at the top along the first direction. The misalignment of the weld is in the range of 0~2mm, and the bevel gap is in the range of 2mm~4mm.

6. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The spacing between adjacent anti-deformation fixtures along the length of the weld is 500mm to 700mm. Alternatively, the spacing between adjacent anti-deformation fixtures along the length of the weld is 600mm.

7. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The first thickness is the same as the second thickness.

8. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The first thickness is 50% to 70% of the total thickness of the weld, or the first thickness is 60% of the total thickness of the weld; The second thickness is 50% to 70% of the total thickness of the weld, or the second thickness is 60% of the total thickness of the weld.

9. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The anti-deformation fixture is a Lamer fixture.

10. The anti-deformation welding method for limiting transverse shrinkage of welds as described in claim 1, characterized in that, The anti-deformation fixture has a thickness of 40mm, a height of 100mm, a length of 200mm, and a bottom arched structure radius of 50mm.

Images