Welding structure at joint of thin-wall part and thick-wall plate part

Abstract

The utility model relates to a welding structure at the joint of a thin-wall part and a thick-wall plate, which comprises the thin-wall part and the thick-wall plate, and is structurally characterized in that the thin-wall part is provided with a multi-layer fitting structure, and the weldability, the joint strength, the fatigue life and the corrosion resistance of the thin-wall part are improved through the multi-layer fitting structure. The utility model provides a plurality of implementation schemes provided with a plurality of layers of fitting structures, which are applied to the manufacturing of the stainless steel corrugated compensator, can greatly improve the weldability of the welding of the thin-wall corrugated pipe and the thick-wall end cover plate, prolong the fatigue life of the corrugated pipe at the welding part and improve the corrosion resistance of the joint, and is easy to realize automatic welding. The scheme is low in overall cost, high in efficiency, simple in process and good in reliability, the current ultrathin plate welding problem can be solved, huge economic benefits are generated, the product quality is greatly improved, and the product service life is greatly prolonged.

Description

Technical Field

[0001] The utility model relates to a welding structure at the connection between a thin-walled part and a thick-walled plate part, and is particularly suitable for sealing welding between a thin-walled stainless steel bellows and a thicker cover plate at the end in a metal corrugated compensation container, and belongs to the technical field of welding. Background Art

[0002] The welding of thin-walled plates and thick-walled plates is widely demanded in the manufacturing and engineering industries, but due to the large thickness difference, the weldability and structural reliability of the joints are long-standing problems. In particular, the direct welding of ultra-thin stainless steel plates with a thickness of less than 0.5 mm and plates with a thickness of 5 to 10 mm is very difficult. Even if welded, the fusion quality of thin-walled parts at the weld joint is not easy to control, and various welding defects are prone to occur. In addition, the fatigue resistance of the structure caused by stress concentration is not good. This problem has always affected product quality and the automation of the production process in the field of metal corrugated compensation container manufacturing. The typical structure is a corrugated compensation container formed by welding a stainless steel thin-walled bellows with thick-walled cover plates at both ends.

[0003] At present, the commonly used welding structure and method in the industry is to flatten the first corrugation at the end of the stainless steel bellows (thickness 0.3-0.5mm), and then form a lap joint with the end cover (thickness 4-10mm), and complete the fusion by argon arc welding or seam welding. The main problems of this joint are:

[0004] 1. The thickness of the stainless steel bellows relative to the end cover is too thin, which is very easy to burn through during arc welding, making welding difficult to control and difficult to automate.

[0005] 2. Regardless of whether argon arc welding or seam welding is used, the fatigue performance and corrosion resistance of the welded joint are not good, which is the key weak point of product life and product quality.

[0006] This problem restricts product quality and performance in the manufacturing of large stainless steel corrugated compensating vessels, especially in the manufacturing of corrugated oil storage cabinets for power transformers and corrugated compensating vessels in the petrochemical, steel, energy storage and other fields, and has become a key technology to be broken through. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a welding structure at the connection between a thin-walled part and a thick-walled plate part, which not only ensures the connection strength but also increases the support and reduces the stress concentration at the welding joint.

[0008] In order to solve the above problems, the specific technical solution of the utility model is as follows: a welding structure at the connection between a thin-walled part and a thick-walled plate part, comprising a thin-walled part and a thick-walled plate part, the thin-walled part is provided with a multi-layer bonding structure, that is, an overlapping part is provided on the inner side or the outer side of the thin-walled part, the overlapping part and the end of the thin-walled part are bent and flattened together to form a multi-layer bonding structure fixed together, the end of the multi-layer bonding structure is overlapped with the thick-walled plate part, and the overall melting welding is completed at the overlapping end to form a lap weld.

[0009] The layers of the multi-layer laminating structure are fixed by seam welding, or the thin-walled part and the overlapping part are fixed by seam welding.

[0010] The thin-walled parts are stainless steel bellows.

[0011] The overlapping parts are arranged on the outside or inside of the thin-walled parts, and a continuous circumferentially sealed seam weld is added to weld the two layers of the overlapping parts and the thin-walled parts together; the seam weld is located on the upper side of the crest or the lower side of the crest of the bulging corrugation.

[0012] A welding structure at the connection between a thin-walled part and a thick-walled plate part comprises a thin-walled part and a thick-walled plate part. The thin-walled part is provided with a multi-layer bonding structure, that is, the ends of the thin-walled part are bent and flattened to form a multi-layer bonding structure, and a seam weld is provided on the multi-layer bonding structure; the multi-layer bonding structure is overlapped with the thick-walled plate part, and overall melting welding is completed at the overlapped ends to form an overlap weld.

[0013] A welding structure at the connection between a thin-walled part and a thick-walled plate part comprises a corrugated thin-walled part and a thick-walled plate part, wherein the thin-walled part is provided with a multi-layer bonding structure, i.e., the end of the thin-walled part is welded to one end of an overlapping part having a thickness greater than that of the thin-walled part through a seam weld, and the other end of the overlapping part is bent and flattened to form a multi-layer bonding structure, and the multi-layer bonding structure is overlapped with the thick-walled plate part, and overall melting welding is completed at the overlapped end to form a lap weld.

[0014] This application adopts the above structure, which has the following advantages:

[0015] 1. The welding parts of thin-walled parts are bent and flattened together with the overlapping parts to form a multi-layer bonding structure with better burn-through resistance and weldability. This not only improves the fusion protection of thin-walled parts, increases the amount of molten metal of thin-walled parts by more than double, and reduces the risk of burn-through, but also acts as a fusion filler to increase the joint strength and improve the fatigue life of thin-walled parts.

[0016] 2. Adding seam welds can fix multiple layers tightly, further eliminate the gap between layers after flattening, help heat conduction and fusion, avoid warping and deformation caused by welding heat leading to burn-through, achieve melting of the upper layer and take over the lower layer, and avoid burn-through of the upper layer caused by the fitting gap.

[0017] 3. After the bellows thin-walled parts and the end plate thick-walled parts are welded to set up a multi-layer bonding structure, the weldability of the thin-walled parts is greatly improved, the risk of melting and burning through is greatly reduced, and even basically does not occur, the process state is stable, creating favorable conditions for realizing welding automation.

[0018] 4. The overlapped parts are sheathed together with the reserved straight wall section of the bellows, and the corrugations are expanded after seam welding. This can greatly simplify the difficulty of seam welding the multi-layer bonding structure after the corrugation is formed, and can ensure the quality of seam welding. It is particularly suitable for arranging the overlapped parts on the outside of the thin-walled parts, which can ensure the sealing of the two layers after seam welding, avoid the occurrence of false welding detachment and fusion gap between thin-walled parts and thick-walled plates that affect the sealing of the weld, can improve the process weldability and process stability, and is conducive to the realization of automated welding.

[0019] 5. The seam weld is set on the upper part of the bulging corrugation, which can realize the transition of thin-walled parts from single layer to multiple layers at the upper part of the weld, increase the bending support, effectively reduce the bending stress concentration of thin-walled parts at the weld, and greatly improve the fatigue life of thin-walled parts at the joint.

[0020] 6. When the thickness of the thin-walled parts reaches or exceeds 0.5mm, the overlapping parts can be omitted and the process can be simplified. By flattening the thin-walled parts themselves and adding seam welds to form a multi-layer fitting fixed structure, burn-through can also be prevented, weldability can be improved, and the performance of the joint can be increased.

[0021] 7. Usually thin-walled parts and overlapping parts are made of stainless steel, and thick-walled plates can be made of carbon steel. After setting up a multi-layer bonding structure and adding overlapping parts, the fusion amount of stainless steel material in the joint can be increased, thereby improving the corrosion resistance of the joint.

[0022] 8. When the overlapping parts are made of stainless steel plates with a thickness of 0.6 mm or more, the process can be simplified. That is, after the ends of the thin-walled parts are seam-welded to the overlapping parts, it is only necessary to bend the overlapping parts into corrugations and flatten them to form a multi-layer bonding structure, and then weld them to the thick-walled parts.

[0023] The above solution is applied in the manufacture of stainless steel bellows compensators, which can greatly improve the weldability of thin-walled bellows and thick-walled end covers, improve the fatigue life of the bellows at the welding part and the corrosion resistance of the joints, and facilitate automatic welding. The overall cost is low, the efficiency is high, the process is simple, and the reliability is good.

[0024] This solution will solve the current welding problems when used in the manufacture of a large number of stainless steel corrugated containers, generate huge economic benefits, and greatly improve product quality and life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the welding structure of Example 1.

[0026] Figure 2 This is a schematic diagram of the welding structure of Example 2.

[0027] Figure 3 This is a schematic diagram of the welding structure of Example 3.

[0028] Figure 4 This is a schematic diagram of the welding structure of Example 4.

[0029] Figure 5 Schematic diagram of welding steps in Example 4.

[0030] Figure 6 This is a schematic diagram of the welding structure of Example 5.

[0031] Figure 7 This is a schematic diagram of the welding steps of Example 5.

[0032] Figure 8 This is a schematic diagram of the welding structure of Example 6.

[0033] Fig. 9 This is a schematic diagram of the welding steps of Example 6.

[0034] Fig.10 This is a schematic diagram of the welding structure of Example 7.

[0035] Fig.11 This is a schematic diagram of the welding steps of Example 7.

[0036] Fig.12 This is a schematic diagram of the welding structure of Example 8.

[0037] Fig.13 This is a schematic diagram of the welding structure of Example 9.

[0038] Fig.14 This is a schematic diagram of the welding steps of Example 9.

[0039] Fig.15 This is a schematic diagram of the welding structure of Example 10.

[0040] Fig.16 This is a schematic diagram of the welding structure of Example 10.

[0041] Fig.17 This is a schematic diagram of the welding steps of Example 10.

[0042] Among them: 1---thin-wall parts, 2---thick-walled panels, 3---overlap parts, 4---lap welds, 5---seam welds, 6---expanded mold flaps of the bulging mold, 7---bulging mold. DETAILED DESCRIPTION Embodiment 1

[0043] A welding structure at the connection between a thin-walled part and a thick-walled plate, wherein the thin-walled part 1 has a thickness of 0.2 to 0.8 mm, and the thick-walled plate 2 has a thickness of 5 to 10 mm. Both are metal plates and need to be reliably welded together, and the weld must ensure sealing. Direct welding of the thin-walled part 1 and the thick-walled plate 2 is likely to cause the thin-walled part with poor heat resistance to burn through, making it difficult to ensure quality.

[0044] The welding structure given in this embodiment is as follows Figure 1 As shown, a multi-layer bonding structure is provided, and a stacking piece 3 is added. The material is the same as that of the thin-walled piece 1 or the performance is better than that of the thin-walled piece 1, and the thickness is equal to or slightly larger than that of the thin-walled piece 1. In this embodiment, when the thin-walled piece is 0.4 mm thick, the stacking piece 3 is selected to be 0.5 mm thick and 40 mm wide, so that it can be bent and folded 180 degrees together with the thin-walled piece 1, and the length is consistent with the thin-walled piece 1.

[0045] Specific implementation steps: first overlap the thin-walled part 1 and the overlapping part 3, then bend them together 180 degrees and flatten them with a pressure wheel to form a multi-layer bonding structure, so that each layer is tightly fitted and fixed, and the end of the multi-layer bonding structure is overlapped with the thick-walled panel 2. At the overlapping joint, use argon arc welding, laser welding or other welding methods to fuse the three together as a whole to form a lap weld 4.

[0046] The overlapping part 3 can be arranged on the inner side or the outer side of the bend of the thin-walled part 1. If it is arranged on the inner side, it can play a supporting role for the thin-walled part 1 when it is melted during welding to avoid burning through; if it is arranged on the outer side, it can be used as a filler for the thin-walled part 1 when it is melted during welding to improve weldability and weld quality. However, if it is arranged on the outer side, two layers need to be melted through to avoid false welding of the thin-walled part 1.

[0047] The thin-walled part 1 and the overlapping part 3 can be bent together using a mold and a flanging machine, and flattened using a rolling wheel or a press. The purpose of flattening is to ensure that the layers of the formed lap joint are tightly fitted and fixed so that they can be fused together during subsequent welding. Embodiment 2

[0048] like Figure 2 As shown, a welding structure for the connection between a thin-walled part and a thick-walled plate part is provided. To achieve reliable welding of the thin-walled part 1 and the thick-walled plate part 2, the four layers of the multi-layer bonding structure are fixed by seam welds 5, and the remaining structures are the same as those in the first embodiment.

[0049] Specific implementation steps: after the thin-walled part 1 and the overlapping part 3 are bent and flattened together, a four-layer multi-layer bonding structure is formed, and the four-layer multi-layer bonding structure is continuously seam welded or intermittently seam welded using a seam welding process to form a seam weld 5. Finally, the multi-layer bonding structure is overlap-welded with the thick-walled panel 2, and argon arc welding, laser welding and other welding methods are used to form overlap welds 4. The remaining steps are the same as in Example 1. Embodiment 3

[0050] like Figure 3As shown, a welding structure for the connection between a thin-walled part and a thick-walled plate part is provided. To achieve reliable welding of the thin-walled part 1 and the thick-walled plate part 2, the two layers of the thin-walled part 1 and the overlapping part 3 are fixed together with a seam weld 5, and the rest of the structure is the same as that of the first embodiment.

[0051] Specific implementation steps: first, the thin-walled part 1 and the overlapping part 3 are seam welded together using a seam welding machine to form a seam weld 5, and then the overlapping part of the two is bent 180 degrees and flattened, and then overlapped with the thick-walled panel 2, and a lap weld 4 is formed by welding methods such as argon arc welding, laser welding or resistance seam welding.

[0052] Seam welding is performed before the thin-walled part 1 and the overlapping part 3 are bent, which makes it easier to ensure the sealing of the seam welding and reduce the difficulty of operation.

[0053] The overlapping part 3 can be arranged on the inner side of the thin-walled part 1 or on the outer side. In this embodiment, it is arranged on the outer side, and the seam weld 5 is arranged above the bending part. In this way, the seam weld 5 can not only improve the weldability and avoid the gap affecting the fusion, but also improve the sealing reliability of the welding 4, prevent the leakage caused by the interlayer cold welding, and at the same time form support and thickness transition of the connection part, reduce the stress concentration of the joint, and improve the fatigue life. Embodiment 4

[0054] Typical welded structure of corrugated compensating container products.

[0055] The thin-walled component 1 of this embodiment is a large stainless steel bellows, and the thick-walled plate 2 is the end cover plate of the container formed with the bellows. The two are welded to form a sealed bellows compensation container, which is used to compensate for the thermal expansion and contraction of the oil volume of a large transformer. In order to ensure that the end cover plate has sufficient rigidity and strength, the thickness of the thick-walled plate 2 is often more than 8 times the thickness of the thin-walled component 1, and the thick-walled plate 2 can be carbon steel or stainless steel. The thin-walled component 1 of the bellows in this embodiment is made of stainless steel with a thickness of less than 0.5 mm, the end thick-walled plate 2 is made of carbon steel with a thickness of 4 to 10 mm, and the added overlapping component 3 is made of stainless steel with a thickness of 0.5 mm to 0.7 mm.

[0056] like Figure 4 As shown, the overlapping piece 3 is bonded and fixed on the inner or outer side of the thin-walled part 1, and the overlapping piece 3 and the end of the thin-walled part 1 are bent and flattened together to form a multi-layer bonding structure. The multi-layer bonding structure is overlapped with the thick-walled panel 2, and the overlap weld 4 is formed by melting welding of the outer end of the multi-layer bonding structure.

[0057] The specific implementation steps are as follows: Figure 5 The process steps are shown in

[0058] 1) Before the corrugation of the bottom of the stainless steel bellows is formed, an annular overlapping piece 3 is coaxially sleeved on the inner or outer side of the straight-walled tube blank;

[0059] 2) using a corrugated bulging die 7, and bulging the thin-walled part 1 and the overlapping part 3 together into corrugations through the expansion die halves 6 of the bulging die;

[0060] 3) The bulging corrugations are then flattened by an extrusion wheel;

[0061] 4) Finally, the flattened portion is welded to the end plate of the thick-walled plate 2 to form a lap weld 4. Embodiment 5

[0062] See Figure 6 As shown, a seam weld 5 is provided on the multi-layer bonding structure of the thin-walled component 1 and the overlapping component 3 to fix each layer, and the remaining structure is the same as that of the fourth embodiment.

[0063] The specific implementation steps are as follows: Figure 7 As shown in the process steps, after step 3 of the fourth embodiment, the seam weld 5 is completed by resistance seam welding to fix the seams of the layers at the flattened position. If the overlapped member 3 is outside, the seam weld 5 needs to be continuously sealed to prevent the inner layer from leaking; if the overlapped member 3 is inside, the seam weld 5 can be welded intermittently; finally, the end of the corrugated pipe and the thick-walled plate 2 flattened together with the overlapped member 3 is overlap-welded with the thick-walled plate 3 to form a weld 4. Embodiment 6

[0064] See Figure 8 As shown, the two layers of the thin-walled member 1 and the overlapping member 3 are bonded together with a seam weld 5 to fix the two layers, and the rest of the structure is the same as that of the fourth embodiment.

[0065] The welding method of the connection between thin-walled parts and thick-walled plate parts is specifically described, including the following steps: Fig. 9 The process steps are shown below:

[0066] 1) Before the corrugation of the thin-walled part 1 of the bellows is formed at the final end, a lapped part 3 is put on the straight edge of the unexpanded corrugation. The lapped part 3 is an annular ring with a thickness not less than that of the thin-walled part 1, and is put together with the straight wall section reserved for the bellows. It can be put on the outside or the inside;

[0067] 2) The overlapping parts of the bellows and the overlapped member 3 are circumferentially welded together by seam welding to form a seam weld 5;

[0068] 3) The overlapping part of the bellows and the overlapped part 3 is expanded by a bellows forming machine to form corrugations; specifically, the expansion die 7 is coaxially arranged at the lower end of the inner part of the bellows, and the expansion die 6 of the expansion die is started to expand the bellows and the overlapped part 3 again, and the seam weld 5 is located on the upper side of the corrugated wave crest;

[0069] 4) Use a rolling wheel or press to flatten the wave crest;

[0070] 5) The flattened end is overlapped with the thick-walled plate 2 to ensure that the formed overlap joint fits tightly and can be fused together, and fusion welding is performed to form an overlap weld 4.

[0071] The overlapped part 3 can be made of the same stainless steel material as the thin-walled part 1, with a thickness of 0.6mm, which is greater than the 0.5mm thickness of the corrugated tube, and a width that covers the wave crest to be expanded, usually 60% of the warp length of a single corrugation. The overlapped part 3 is made into an annular plate ring by cutting steel strips and butt welding, and is preferably placed outside the straight wall of the thin-walled part 1 corrugated tube where the corrugation is not expanded, or inside the straight wall. The annular circumference is preferably as small as the gap with the thin-walled part 1.

[0072] The overlapped part 3 can be welded in advance at the predetermined position of the end on the tube blank before the corrugation of the thin-walled part 1 is formed, and then all the corrugations are continuously formed. When the overlapped part 3 is sleeved on the outer side of the tube blank of the thin-walled part 1, the seam weld 5 should be a sealing weld.

[0073] The bellows forming machine can adopt the existing forming machine and mold of the bellows production plant.

[0074] When the thin-walled component 1 and the overlapping component 3 are melt-welded with the thick-walled plate component 2, a filler wire may be used, or no filler wire may be used, that is, the melted overlapping component 3 is used as a filler.

[0075] Pre-seaming the overlapped parts 3 and the thin-walled parts 1 can greatly improve the strength of the thin-walled parts 1 at the joints, reduce the bending stress during corrugation expansion and contraction, and improve fatigue life, while also increasing the corrosion resistance of the welded joints when the thick-walled panels 2 are made of carbon steel.

[0076] The overlapped part 3 and the thin-walled part 1 are seam welded by a conventional commercially available resistance seam welder and a rolling welder, and the weld is located on the side wall of the corrugation to be expanded near the existing corrugation. The seam weld 5 further ensures the airtightness of the overlap weld 4, while increasing the connection strength of the thin-walled part 1 by more than one time. The wrapping structure of the overlapped part 3 on the thin-walled part 1 also improves the corrosion resistance of the joint when the thick-walled plate 2 is not stainless steel. Embodiment 7

[0077] See Fig.10 As shown, the structure is the same as that of the sixth embodiment, but the seam weld 5 is located below the portion where the overlapping part 3 and the thin-walled part 1 are bent and flattened together.

[0078] The welding method of the connection between thin-walled parts and thick-walled plate parts is specifically described, including the following steps: Fig.11 The process steps are shown below:

[0079] 1) Before the thin-walled part 1 bellows is formed into the final end corrugation on the forming machine, the overlapping part 3 is put on the inner side of the straight edge section without corrugation;

[0080] 2) The overlapping parts of the bellows and the overlapped part 3 are welded together by seam welding to form seam weld 5, which fixes the overlapped part 3 to prevent it from falling off during subsequent forming. The weld position is selected at the lower part of the crest of the corrugation to be expanded. There is no sealing requirement for the weld, and intermittent welding or spot welding can be used;

[0081] 3) The overlapping part of the bellows and the overlapping part 3 is expanded into corrugations by a bellows forming machine, and the crest of the corrugation is above the seam weld 5;

[0082] 4) Use a rolling wheel or press to flatten the wave crest;

[0083] 5) The flattened end is overlapped with the thick-walled plate 2 and fusion-welded to form an overlap weld 4.

[0084] In this solution, the overlapping part 3 is preferably placed on the inner side of the thin-walled part 1 to avoid the risk of sealing due to poor melting of the interlayer weld when placed on the outer side. Embodiment 8

[0085] like Fig.12 As shown, a welding structure at the connection between a thin-walled part and a thick-walled plate part includes a thin-walled part 1 and a thick-walled plate part 2. In order to improve weldability and realize welding between the two, the end of the thin-walled part 1 is bent and flattened at least once to form a multi-layer bonding structure. This embodiment adopts a structure that is bent 180 degrees and flattened once as the multi-layer bonding structure, and a seam weld 5 is arranged on the multi-layer bonding structure; the multi-layer bonding structure 8 is overlapped with the thick-walled plate part 2, and a lap weld 4 is formed by melting welding of the outer end of the multi-layer bonding structure 8.

[0086] Specific implementation steps: first bend the thin-walled part 1 180 degrees and flatten it with a pressure wheel, then complete the seam welding of the flattened part through a resistance welding process to form a seam weld 5, and finally overlap weld it with the thick-walled plate part 2, and use argon arc welding, laser welding or resistance seam welding to form an overlap weld 4.

[0087] The thin-walled part 1 is bent 180 degrees and flattened, so that the lower plate supports the upper plate during welding and melting, which is equivalent to adding the overlapping part 3 to avoid burning through; the formation of the seam weld 5 can ensure that the upper and lower layers are tightly fixed, eliminate the gap, and improve the weldability. The seam weld 5 allows intermittent welding or spot welding. This solution is suitable for the case where the thin-walled part 1 is not very thin, such as more than 0.5mm, which can improve production efficiency and simplify the process. However, if it is very thin, due to poor heat resistance, the weldability is not as reliable as adding the overlapping part 3. Embodiment 9

[0088] like Fig.13As shown, this embodiment is the application of the eighth embodiment on the corrugated compensator, and the welding structure of the lap welded joint 4 formed by the stainless steel bellows thin-walled member 1 with a thickness of 0.5 mm and the thick-walled plate member 2 with a thickness of 6 mm. Among them, the end of the thin-walled member 1 is bent at least once and then flattened to form a multi-layer bonding structure, and a seam weld 5 is arranged on the multi-layer bonding structure; the multi-layer bonding structure is overlapped with the thick-walled plate member 2, and the lap weld 4 is formed by melting welding of the outer end of the multi-layer bonding structure.

[0089] The specific implementation steps are as follows: Fig.14 As shown in the process steps, after the corrugations at the end of the corrugated tube are formed, the corrugations at the end are flattened by roller extrusion or pneumatic hammer pressing to form a 180-degree fold, and then the weld 5 is formed by resistance seam welding on a resistance welding machine, the flattened upper and lower layers are tightly fixed, and finally the flattened end is placed on the thick-walled end plate, i.e., the thick-walled plate 2, and the lap weld joint 4 is completed by a melting welding process. Embodiment 10

[0090] like Fig.15 As shown, a multi-layer bonding structure is arranged at the end of the thin-walled part 1, that is, the end of the thin-walled part 1 is welded to one end of an overlapping part 3 whose thickness is greater than that of the thin-walled part 1 through a seam weld 5, and the other end of the overlapping part 3 is bent and flattened to form a multi-layer bonding structure, and the multi-layer bonding structure is overlapped with the thick-walled plate part 2, and overall melting welding is completed at the overlapped end to form a overlap weld 4.

[0091] like Fig.16 As shown, when the thin-walled part 1 is a stainless steel corrugated tube, one end of the overlapping part 3 is seam welded to the end of the thin-walled part 1, and the other end of the overlapping part 3 is formed into corrugations and then flattened to form a multi-layer bonding structure, and then overlap-welded with the thick-walled plate part 2.

[0092] The specific implementation steps are as follows: Fig.17 As shown:

[0093] 1) Put the annular tube blank of the overlapped part 3 on the end of the thin-walled part 1 of the bellows and use a seam welding machine to perform circumferential seam welding to ensure the weld is sealed;

[0094] 2) Exposing the end of the thin-walled bellows part 1 to the annular tube blank of the overlapping part 3, and expanding the corrugations by a bellows forming machine 7;

[0095] 3) Flattening the corrugations of the overlapping member 3 with bulging corrugations to form a multi-layer laminating structure;

[0096] 4) The end of the multi-layer bonding structure is overlapped with the thick-walled part 2, and the overlapped end is melt-welded to form an overlap weld 4.

[0097] The thickness of the thin-walled bellows part 1 is below 0.5 mm, and the thickness of the overlapped part 3 is between 0.6 and 0.8 mm, both of which are made of stainless steel. The width of the tube blank of the overlapped part 3 is 80 mm, which is sufficient for corrugation forming.

[0098] In the above-mentioned sixth and seventh embodiments, the seam weld 5 between the thin-walled part 1 of the bellows and the overlapped part 3 should be arranged on the side wall of the bulging corrugation and avoid being arranged on the crest, which is beneficial to improving the bending fatigue life of the seam weld 5 and avoiding weld fatigue cracking caused by stress concentration.

[0099] In the above-mentioned embodiments 4 to 10, except for embodiment 8, all involve the thin-walled part 1 being a corrugated tube and an overlapping part 3 or the thin-walled part 1 itself forming a multi-layer bonding structure. For those skilled in the art, it is possible to choose to first form the corrugated tube and then set the multi-layer bonding structure, or to set the multi-layer structure on the tube blank of the corrugated tube thin-walled part 1. After the setting is completed, the corrugations are continuously formed on a corrugated tube forming machine, and the last corrugation is flattened and bonded to form a multi-layer bonding structure. The above are all within the protection scope of the present application.

Claims

1. A welding structure at the connection between a thin-walled component and a thick-walled plate component, comprising a thin-walled component (1) and a thick-walled plate component (2), characterized in that: The thin-walled member (1) is provided with a multi-layer bonding structure, that is, an overlapping member (3) is provided on the inner side or the outer side of the thin-walled member (1), and the overlapping member (3) and the end of the thin-walled member (1) are bent and flattened together to form a multi-layer bonding structure fixed together, and the end of the multi-layer bonding structure is overlapped with the thick-walled plate member (2), and the overall melting welding is completed at the overlapped end to form an overlap weld (4).

2. The welding structure at the connection between the thin-walled member and the thick-walled plate member according to claim 1 is characterized in that: The layers of the multi-layer laminating structure are fixed via seam welds (5), or the thin-walled component (1) and the overlapping component (3) are fixed via seam welds (5).

3. The welding structure at the connection between the thin-walled member and the thick-walled plate member according to claim 1 or 2, characterized in that: The thin-walled part (1) is a stainless steel bellows.

4. The welding structure at the connection between the thin-walled member and the thick-walled plate member according to claim 3 is characterized in that: The overlapping part (3) is arranged on the outside or inside of the thin-walled part (1), and a continuous circumferentially sealed seam weld (5) is added to weld the overlapping part (3) and the thin-walled part (1) together; the seam weld (5) is located on the upper side of the crest or the lower side of the crest of the bulging corrugation.

5. A welding structure at the connection between a thin-walled component and a thick-walled plate component, comprising a thin-walled component (1) and a thick-walled plate component (2), characterized in that: The thin-walled member (1) is provided with a multi-layered bonding structure, that is, the ends of the thin-walled member (1) are bent and flattened to form a multi-layered bonding structure, and a seam weld (5) is provided on the multi-layered bonding structure; the multi-layered bonding structure is overlapped with the thick-walled plate member (2), and overall melting welding is completed at the overlapped ends to form an overlap weld (4).

6. A welding structure at the connection between a thin-walled component and a thick-walled plate component, comprising a bellows thin-walled component (1) and a thick-walled plate component (2), characterized in that: The thin-walled member (1) is provided with a multi-layered bonding structure, that is, the end of the thin-walled member (1) is welded to one end of an overlapping member (3) having a thickness greater than that of the thin-walled member (1) through a seam weld (5), and the other end of the overlapping member (3) is bent and flattened to form a multi-layered bonding structure. The multi-layered bonding structure is overlapped with the thick-walled plate member (2), and overall melting welding is completed at the overlapped end to form an overlap weld (4).

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