A method of metal suturing and a suture metal roll

Abstract

The application discloses a metal stitching method and a stitched metal roll, and belongs to the technical field of metal stitching. The metal stitching method can improve the stitching seam strength, avoid problems such as cracking, belt breaking or edge cracking of the stitching seam, and thus improves the production efficiency and stability of a unit. The metal stitching method comprises the following steps: overlapping a first end portion of a first metal roll on a second end portion of a second metal roll to form an overlapping structure; starting an upper punch and a lower punch to stamp the overlapping structure to form at least one first inserting portion on the first end portion and at least one second inserting portion on the second end portion; pulling the first metal roll and the second metal roll in two opposite directions respectively to make the second inserting portion located below inserted into the first inserting portion located above and locked, so as to form a mechanically interlocked metal roll combination; and based on the mechanically interlocked metal roll combination, spot welding is performed on multiple positions on the first end portion located above, so as to obtain a stitched metal roll.

Description

Technical Field

[0001] This application belongs to the field of metal sewing technology, and particularly relates to a metal sewing method and a sewing metal roll. Background Technology

[0002] In the stretching and leveling unit of a continuous production line for metal coils, a stitching machine is commonly used to interlock the beginning and end of the coil to ensure production continuity.

[0003] However, the seams formed by the relevant technology have an overlap, which can easily interfere with components such as the squeeze roller and brush roller when passing through the washing and rinsing sections. This can cause the seams to fold, significantly reducing their connection strength and potentially leading to problems such as seam cracking, belt breakage, or edge cracking, which seriously affects the production efficiency and stability of the unit. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a metal stitching method and a stitched metal roll, which can improve the strength of the stitch and avoid problems such as stitch cracking, strip breakage, or edge cracking, thereby improving the production efficiency and stability of the unit.

[0005] In a first aspect, this application provides a metal stitching method, comprising: The first end of the first metal roll is overlapped with the second end of the second metal roll to form an overlap structure; The upper and lower punches are activated to punch the overlapping structure to form at least one first insertion portion on the first end and at least one second insertion portion on the second end, wherein the first insertion portion and the second insertion portion are configured as complementary structures that can be inserted into each other. Pull the first metal roll and the second metal roll in opposite directions respectively, so that the second plug portion located below inserts into the first plug portion located above and locks in place, thereby forming a mechanically interlocking metal roll assembly; Based on the mechanically interlocked metal roll assembly, spot welding is performed at multiple locations on the first end located above to obtain a stitched metal roll; The spot welding energy of each weld point is controlled to penetrate the first end so that the weld point fuses the first end with the second end located below.

[0006] In some embodiments, each solder joint has a solder joint distance from the edge of the first end, and the solder joint distance is greater than a preset distance.

[0007] In some embodiments, the first plug-in portion and the second plug-in portion are both protrusions formed by stamping on the corresponding metal coil, and in the width direction of the metal coil, both sides of each protrusion are disconnected from the metal coil body.

[0008] In some embodiments, both the first insertion portion and the second insertion portion include an insertion section and a locking section that are connected end to end; The insertion section has a first width in the lateral direction of insertion, and the locking section has a second width in the lateral direction of insertion, wherein the first width is smaller than the second width.

[0009] In some embodiments, the upper and lower punches are activated to stamp the overlapping structure, specifically including: The upper and lower punches are activated to move towards each other and simultaneously punch the overlapping structure.

[0010] In some embodiments, based on the metal coil assembly, spot welding is performed at multiple locations on the upper first end, specifically including: Based on the metal roll assembly, at least two spot welding operations are performed on the first end located at the top, and the positions of the weld points of different batches of spot welding operations are staggered from each other along the width direction of the metal roll.

[0011] In some embodiments, the metal stitching method further includes: Based on the stitched metal roll, continuous welding is performed along the mating edge of the first metal roll and the second metal roll so that the side of the first metal roll is connected to the body of the second metal roll by a weld.

[0012] In some embodiments, the metal stitching method further includes: based on the stitched metal roll, activating a flattening roller to flatten the stitched structure.

[0013] In some embodiments, when the first metal roll or the second metal roll is fixed on the take-up roller, the metal stitching method further includes: activating the take-up roller to take up the stitched metal roll.

[0014] Secondly, this application provides a stitched metal roll, which is obtained by stitching the first metal roll and the second metal roll together using the metal stitching method described in the first aspect.

[0015] The metal stitching method of this application first forms a complementary interlocking structure through stamping and mechanical locking, thereby positioning and fixing the first and second metal coils. This provides the operating conditions for subsequent spot welding operations, ensuring precise weld point positioning and tight adhesion of the interfaces to be welded. Then, based on these operating conditions, through-welding is performed. The welding process does not need to overcome or compensate for the unstable heat conduction caused by material displacement or gaps. Therefore, each weld point can reliably fuse the upper and lower metal layers, forming a strong connection structure and significantly improving the overall strength of the joint. Furthermore, the spot welding operation of this application is through-welding. Compared to edge welding, through-welding ensures that the upper and lower metal layers are fused simultaneously during the welding process, thus guaranteeing the connection strength of the two metal layers and avoiding problems such as seam cracking, strip breakage, or edge cracking, thereby improving the production efficiency and stability of the unit. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic top view of the first and second metal rolls after they have been overlapped, according to one or more embodiments of this application; Figure 2 This is a schematic side view of the first and second metal rolls after they have been overlapped, according to one or more embodiments of this application; Figure 3 This is a schematic top view of the first and second metal rolls after being plugged in, according to one or more embodiments of this application; Figure 4 This is a schematic top view of the first and second plug-in portions provided in one or more embodiments of this application before they are plugged in; Figure 5 This is a schematic top view of the first and second plug-in portions after they are plugged in, according to one or more embodiments of this application; Figure 6 This is a schematic structural diagram of the plug-in portion provided in one or more embodiments of this application; Figure 7 This is a schematic top view of the first and second metal coils after continuous welding, as provided in one or more embodiments of this application; Figure 8 This is a schematic flowchart of a metal stitching method provided in one or more embodiments of this application. Detailed Implementation

[0017] To better understand the technical solutions provided in the embodiments of this specification, the technical solutions of the embodiments of this specification will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0018] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, 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. Without further limitation, a requirement defined by "comprising one..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element. The term "two or more" refers to cases where two or more elements are included.

[0019] The seams formed by the relevant technology have an overlap, which can easily interfere with components such as the squeeze roller and brush roller when passing through the washing and rinsing sections. This can cause the seams to fold, significantly reducing their connection strength and potentially leading to problems such as seam cracking, strip breakage, or edge cracking, which seriously affects the production efficiency and stability of the unit.

[0020] In view of this, the present application provides a metal sewing method and a sewing metal roll, which can improve the strength of the sewing seam and avoid problems such as seam cracking, strip breakage or edge cracking, thereby improving the production efficiency and stability of the unit.

[0021] It should be noted that the metal stitching method provided by this invention is suitable for joining metal coils (such as aluminum coils, steel coils, etc.) on a continuous production line to form ultra-long continuous coils, meeting the needs of subsequent processing (such as continuous coating, continuous plating, continuous stamping). This method combines the advantages of mechanical interlocking and spot welding fusion, achieving efficient, high-strength, and reliable metal coil connections.

[0022] refer to Figures 1 to 3 This embodiment uses the connection of two silicon steel coils as an example to explain in detail the implementation steps of this method. The thickness of the silicon steel coils ranges, for example, from 0.1 mm to 2.0 mm. Figure 8 As shown, the metal stitching method includes the following steps: Step S101: The first end 101 of the first metal roll 100 is overlapped with the second end 201 of the second metal roll 200 to form an overlap structure 300.

[0023] First, the first metal roll 100 and the second metal roll 200 are guided into the sewing station by an uncoiler (not shown). On the support platform of the sewing machine (such as the punch platform below), the end of the first metal roll 100 (i.e., the first end 101) is overlapped with the beginning of the second metal roll 200 (i.e., the second end 201), thereby forming an overlapping structure 300. The overlap length L (e.g., ...) Figure 1 and Figure 2 (As shown) The overlap width can be set according to the metal thickness and strength requirements, typically ranging from 10mm to 50mm, for example, 15mm. The overlap width should match the width of the metal coil. Ensure the overlap area is flat and free of oil or severe oxide layers to guarantee the quality of subsequent connections.

[0024] Step S102: The upper punch and lower punch (not shown in the figure) are activated to punch the overlapping structure 300 to form at least one first insertion part 1011 on the first end 101 and at least one second insertion part 2011 on the second end 201, wherein the first insertion part 1011 and the second insertion part 2011 are configured as complementary structures that can be inserted and mated with each other.

[0025] The drive unit (such as a hydraulic or servo motor) of the sewing machine is activated, driving the upper punch downward to work in conjunction with the fixed (or synchronously moving in opposite directions) lower punch to stamp the overlapping structure 30. The stamping action is performed at one or more predetermined positions along the length of the overlapping area.

[0026] In a single stamping stroke, the bottom of the upper punch has at least one first forming portion (e.g., a protrusion), and the top of the lower punch has a second forming portion (e.g., a groove) that complements the first forming portion. During stamping, the protrusion of the upper punch partially presses the first end 101 downward, causing its material to flow into the groove of the lower punch and undergo plastic deformation, thereby forming a downwardly protruding first insertion portion 1011 (e.g., a boss or a hook-like portion) on the first end 101. Simultaneously, the protrusion (or the edge of the groove) of the lower punch presses the corresponding portion of the second end 201 upward, causing it to deform within the groove (or the gap between the protrusions) of the upper punch, thereby forming an upwardly protruding second insertion portion 2011 (e.g., a groove or another hook-like portion) on the second end 201. The shapes of the first insertion portion 1011 and the second insertion portion 2011 are precisely designed as complementary structures that can interlock and mate with each other, such as a boss and a groove, a male and a female snap, etc.

[0027] Preferably, multiple pairs of the first insertion portion 1011 and the second insertion portion 2011 are stamped at intervals within the overlap length L. These insertion portions can be arranged in one or more rows along the width direction of the metal roll, or they can be staggered to distribute the force evenly.

[0028] In step S103, the first metal roll 100 and the second metal roll 200 are pulled in opposite directions to insert the lower second plug part 2011 into the upper first plug part 1011 and lock it in place, thereby forming a mechanically interlocking metal roll assembly.

[0029] After stamping is completed, the upper punch returns to its original position. Then, along... Figure 1 The arrows (in opposite directions) pull the first metal coil 100 (solid arrow direction) and the second metal coil 200 (dashed arrow direction) respectively. Since the first insertion part 1011 is located on the upper layer (first end 101) and the second insertion part 2011 is located on the lower layer (second end 201), and they are complementary structures, this pulling force forces the lower second insertion part 2011 into or into the corresponding space of the upper first insertion part 1011. Through the beveled, barbed, or interference fit design of the insertion part sidewalls, the two achieve mechanical locking after insertion, making it difficult to disengage in the opposite direction, thus forming a firmly mechanically interlocked metal coil assembly (such as...). Figure 3 (As shown). This mechanical interlocking mechanism can withstand a certain longitudinal tensile force, providing a stable foundation for subsequent spot welding and preventing the coil from shifting during welding.

[0030] Step S104: Based on the mechanically interlocked metal roll assembly, spot welding is performed at multiple locations on the upper first end to obtain a stitched metal roll; wherein, the spot welding energy of each weld point is controlled to penetrate the first end so that the weld point fuses the first end with the lower second end.

[0031] After obtaining the mechanically interlocking metal coil assembly, it is spot-welded to finally complete the stitching. Using a spot welding machine (which can be integrated into the stitching machine), spot welding is performed at multiple locations on the surface of the upper first end 101, avoiding the interlocking portion. Figure 3 As shown, solder joints 400 are evenly distributed in the overlapping area.

[0032] The key parameter for spot welding is energy control. Welding current, time, and electrode pressure are precisely set so that the welding energy at each weld point (400°) is sufficient to penetrate the entire thickness of the first end 101 (upper metal layer) and fuse its bottom with the surface of the adjacent second end 201 (lower metal layer). That is, the weld nugget not only forms in the upper metal layer but also extends into the lower metal layer, melting the two metal layers together at the weld point to achieve a metallurgical bond.

[0033] Specifically, the optimal welding parameters can be determined experimentally based on the metal material and thickness. For example, for a 1.0mm thick aluminum coil, medium-frequency DC spot welding can be used with a current of approximately 20kA and a time of approximately 100ms. Post-weld inspection ensures that the weld is strong and free from incomplete welds or overheating. The number, spacing, and arrangement of weld points (such as single or multiple rows) can be designed according to the required connection strength, for example, a spacing of 50mm to 150mm.

[0034] At this point, the first metal coil 100 and the second metal coil 200 are firmly sewn together into a continuous sewn metal coil through a combination of mechanical interlocking and multi-point spot welding, which can then be sent to the subsequent production line for continuous processing.

[0035] As can be seen, the metal stitching method of this application first forms a complementary interlocking structure through stamping and mechanical locking, thereby positioning and fixing the first metal roll 100 and the second metal roll 200. This provides the operating conditions for subsequent spot welding operations, ensuring precise weld point positioning and tight adhesion of the interfaces to be welded. Then, based on these operating conditions, through-welding is performed, eliminating the need to overcome or compensate for unstable heat conduction caused by material displacement or gaps. Therefore, each weld point can reliably fuse the upper and lower metal layers, forming a strong connection structure and significantly improving the overall strength of the joint. Furthermore, the spot welding operation of this application is through-welding. Compared to edge welding, through-welding ensures that the upper and lower metal layers are fused simultaneously during the welding process, thus guaranteeing the connection strength of the two metal layers and avoiding problems such as seam cracking, strip breakage, or edge cracking, thereby improving the production efficiency and stability of the unit.

[0036] In some embodiments, the first insertion portion 1011 may be shaped as an Ω-shaped hook with a downward opening, while the second insertion portion 2011 may be correspondingly shaped as an upwardly protruding trapezoidal block that matches the inner cavity of the Ω-shaped hook. During the pull-locking step, the trapezoidal block is pulled into the inner cavity of the Ω-shaped hook, and its shape interlocks to form a stronger mechanical connection.

[0037] In some embodiments, the position of the weld point can be further optimized in the spot welding process described in step S104. Specifically, as... Figure 3 As shown, the center of each weld point 400 is maintained at a specific weld point distance D from any edge of the first end 101 above in the overlapping area (particularly the side edge along the width direction of the metal roll and the front edge along the length direction).

[0038] The distance D between the weld points can be designed to be greater than a preset distance (the preset distance can be an empirical value obtained from multiple processing tests). This avoids edge defects affecting the weld point quality. During the stamping process to form the interlocking part and the mechanical locking process, there may be slight deformation, work hardening, or material thinning in the edge area of ​​the metal plate. Setting the weld points away from the edges can avoid these potentially unstable areas, ensuring that the weld points are formed in the main body area where the material state is more uniform and stable, thereby obtaining more consistent weld nugget quality and connection strength.

[0039] Furthermore, the spot welding process generates thermal stress, and the weld point itself is also a stress concentration point. If the weld point is too close to the edge of the sheet metal, under the tension of subsequent winding, unwinding, or production line operations, the stress may be directly transferred from the weld point to the free edge, increasing the risk of tearing starting from the edge. Maintaining a sufficient weld point distance D is equivalent to preserving a complete section of material as a buffer zone between the weld point and the free edge, which can effectively disperse stress and improve the durability of the joint under dynamic loads.

[0040] In some embodiments, during the stamping process in step S120, the first insertion part 1011 and the second insertion part 2011 do not form depressions or embossed patterns by locally extruding the surface of the metal coil, but rather by using a mold with a specific cavity structure to cause significant plastic flow and stretching of the metal material, thereby forming an independent protrusion structure in the out-of-plane direction of the sheet metal.

[0041] Specifically, the bottom of the upper punch is provided with a downwardly protruding first forming die, and the top of the lower punch is provided with an upwardly protruding second forming die. The projections of the first forming die and the second forming die in the vertical direction at least partially overlap. When the upper and lower punches are closed to stamp the overlapping structure 300: The first forming die acts on the first end 101, forcefully squeezing the material in the corresponding area downwards, forcing the material to flow into the cavity formed by the side wall of the second forming die and the base surface of the lower punch, thereby forming a downward protruding structure on the first end 101, which is the first insertion part 1011.

[0042] At the same time, the second forming mold acts on the second end 201, forcefully squeezing the material in the corresponding area upward, forcing the material to flow into the cavity formed by the side wall of the first forming mold and the base surface of the upper punch, thereby forming an upward protruding structure on the second end 201, which is the second insertion part 2011.

[0043] Furthermore, in the width direction of the metal coil, both sides of each protrusion are disconnected from the metal coil body. For example... Figure 4As shown in the top view, each formed insertion part, in the direction perpendicular to the metal coil conveying direction (i.e., the width direction W), has its left and right sidewalls 1011a (2011a) and 1011b (2011b) completely separated from the original undeformed metal coil body (i.e., the substrate portion of the first end 101) through stamping shearing or extreme tensile deformation. From the top view, this protruding structure resembles an island or an independent button, with a closed outline that is discontinuous with the surrounding substrate material.

[0044] The separation on both sides makes the first insertion part 1011 an independent, accommodating snap or pocket-like structure, while the corresponding second insertion part 2011 becomes an accommodating tenon or key-like structure. During the pulling and locking process in step S130, the second insertion part 2011 can smoothly insert from its length direction (perpendicular to the width direction W) into the opening space formed by the separated sidewalls below the first insertion part 1011, and achieves mechanical locking through structural interference or hooks, such as... Figure 5 As shown. If the two sides are not separated, and the insertion part is just a bulge on the plate, then this insertion action cannot be achieved, and only a planar fit can be formed. The locking effect and the ability to resist pull-out will be greatly weakened.

[0045] Furthermore, since the connector is an independent protrusion, spot welding can be arranged on the flat substrate area (on the first end 101) between or around the two protrusions. This avoids spot welding on the protrusion structure itself, which may lead to unstable welding quality due to uneven curvature and thickness. Figure 3 As shown, solder joint 400 is arranged in a flat area around the insertion part, which ensures good contact of the electrodes and uniformity of welding quality.

[0046] In a specific example, the first forming die can be designed as a U-shaped or rectangular annular punch with an open bottom, used to stamp the first end 101 into a cap-shaped protrusion (first insertion portion 1011) with its sidewalls disconnected from the substrate and its bottom (the part in contact with the second end) possibly partially connected or completely disconnected. Correspondingly, the second forming die can be designed as a columnar punch that matches the inner cavity of the cap, used to stamp a columnar protrusion (second insertion portion 2011) that can be inserted into the cap-shaped structure on the second end 201. When pulled to lock, the columnar protrusion is engaged into the internal space of the cap-shaped protrusion, completing the mechanical engagement.

[0047] To optimize the smoothness of the mechanical locking process and the reliability of the final locking, the protruding insertion part formed by stamping can be structurally designed with precision. For example... Figure 6 As shown, both the first insertion part 1011 and the second insertion part 2011 are designed to consist of two sections with different functions: an insertion section M1 and a locking section M2.

[0048] The insertion section M1 is located at the leading portion of the mating part (relative to the direction of mechanical insertion). It has a relatively small dimension in the transverse direction perpendicular to the insertion direction (usually parallel to or slightly inclined to the width of the metal coil), defined as the first width W1. The insertion section functions similarly to a guide head or pin, and its small transverse dimension is designed to reduce the difficulty and resistance of alignment during the initial stage of insertion, guiding the mating part smoothly into the mating position.

[0049] The locking section M2 follows immediately after the extending section M1, connecting them end-to-end. It has a relatively large dimension in the same transverse direction, defined as the second width W2, and satisfies W1 < W2. The function of the locking section M2 is to provide the main mechanical interference and locking effect. Its large transverse dimension allows it to form an interference fit, hook, or interlock with the corresponding structure of the complementary insertion part after entering the mating position, thereby generating a strong resistance to reverse disengagement.

[0050] During the pull-locking process in step S130, such as Figure 4 As shown, the insertion section M1 of the second insertion part 2011, with its smaller first width W1, smoothly enters the spacious entrance of the first insertion part 1011. As the pulling continues, the locking section M2 of the second insertion part 2011 (with a larger second width W2) is subsequently pulled into the locking section M2 area of ​​the first insertion part 1011. Since W2 > W1, and the inner width of the locking section M2 of the first insertion part 1011 is designed to be slightly smaller than W2 or has a locking chamfer, the locking section M2 of the second insertion part 2011 will strongly mechanically interfere with or form a hook connection with the inner wall there, thereby achieving a secure locking (e.g., Figure 5 (As shown). This two-stage design, which guides first and then locks, greatly improves the reliability and strength of the mechanical engagement.

[0051] This segmented structural design reduces assembly precision requirements. Specifically, the small insert section M1 lowers the stringent requirements for initial alignment accuracy, making reliable mating possible in high-speed production environments. The segmented structure also enhances locking strength and reliability. The clearly defined clamping section M2, by increasing the lateral contact area or forming a mechanical stop, provides shear and pull-out resistance far exceeding that of a simple boss-groove fit. Therefore, the mating design, which includes the insert section M1 and the clamping section M2 with different widths, achieves efficient and robust mechanical engagement, ensuring that the metal coil assembly possesses high initial connection strength and stability before subsequent spot welding processes.

[0052] In step S140, the metal roll assembly based on mechanical interlocking connection undergoes spot welding operations at multiple locations, with the weld points arranged in a specific pattern to further optimize the connection performance.

[0053] Specifically, the spot welding operation is not completed in one step, but is performed in at least two steps. For example, the first spot welding operation is performed first, forming a first row of weld points on the upper first end 101. This row of weld points is arranged at intervals along a straight line approximately parallel to the width direction W of the metal coil. Subsequently, a second spot welding operation is performed to form a second row of weld points. The position of the second row of weld points is offset from the position of the first row of weld points 71 along the width direction W of the metal coil. That is, from the top view, the second row of weld points is not aligned with the first row of weld points, but is located in the mid-range between two adjacent weld points in the first row or at other offset positions. More than two spot welding operations can be performed to form three or more rows of staggered weld points.

[0054] This staggered arrangement design disperses the heat-affected zone generated by welding across the plane, preventing excessive thermal stress accumulation in localized areas due to overly concentrated weld points. This reduces the tendency for metal plates to warp and helps maintain the flatness of the joint area. Furthermore, the staggered weld points create more evenly distributed connection anchors on the lap surface, more effectively distributing the load over a wider area and improving the fatigue resistance and overall load-bearing capacity uniformity of the joint.

[0055] During implementation, the spot welding machine can be equipped with multiple electrode heads or the welding gun can be moved by program control to automatically and sequentially complete the welding of each batch of misaligned weld points.

[0056] After obtaining the stitched metal coil by spot welding, this method also includes an additional continuous welding step to further enhance the edge integrity, sealing, or strength in a specific direction of the joint.

[0057] Specifically, based on the stitched metal rolls, continuous welding is performed along the mating edges of the first metal roll 100 and the second metal roll 200 using an automated welding device (such as a laser welder, TIG welder, or plasma welder). Figure 7 As shown, this butt joint edge is located outside the overlapping area, that is, at the ridge line formed by the intersection of the end side of the first metal coil 10 and the upper surface of the main body of the second metal coil 20 (or slightly offset depending on the structure). During welding, the welding torch moves at a constant speed along this ridge line to form a continuous weld seam 500.

[0058] This continuous weld 500 achieves a metallurgical connection between the side (thickness surface) of the first metal coil 100 and the body (upper surface) of the second metal coil 200. The continuous weld 500 completely seals the lateral opening formed by the overlap of the two plates, providing a reliable seal for applications requiring protection against liquid, gas, or impurity intrusion (such as certain tank materials and decorative panels). Furthermore, the continuous weld 500 significantly enhances the joint's stiffness and tear resistance perpendicular to the seam direction (i.e., the width direction), providing additional protection against lateral forces during subsequent processing of the metal coil. Additionally, the continuous weld 500 smoothly transitions edges, improving the appearance.

[0059] Spot welding and continuous welding processes introduce localized thermal stress, which may cause slight wavy deformation or unevenness in the welded area. To eliminate this effect and ensure the overall straightness of the welded metal coil meets high-standard subsequent processing requirements, this method includes a flattening process after welding.

[0060] Specifically, based on the stitched metal roll, one or more pairs of flattening rollers are activated. The stitched metal roll is guided through the gap between these flattening rollers. The flattening rollers are typically made of high-strength alloy steel with a high surface hardness and smoothness, and they apply adjustable, uniform pressure to the stitched structure being passed through (particularly the area containing weld points 400, interlocking sections, and continuous welds 500).

[0061] This gentle rolling plastic deformation can correct localized bulges or warping caused by welding thermal cycles. Simultaneously, rolling helps to ensure a tighter fit between the two overlapping metal sheets, eliminating any potential microscopic gaps. It also lightly rolls the weld joint and the surrounding heat-affected zone, helping to refine the grain structure of that area and improving its mechanical properties to some extent.

[0062] The pressure and gap of the flattening roller need to be precisely adjusted according to the metal material, thickness and actual flatness after stitching, in order to achieve the best leveling effect without damaging the material or causing excessive work hardening.

[0063] In some embodiments, before sewing begins, the first metal roll 100 has been unwound, and its front end (first end 101) is drawn to the sewing station, while the second metal roll 200 has been mounted on an unwinding device, and its starting end (second end 201) is sent to the sewing station for overlap. The body of the second metal roll 200 may be pre-wound partially onto a take-up roller, or the take-up roller may be prepared to receive the sewn material.

[0064] After the spot welding in step S140 is completed, a complete stitched metal roll is obtained. At this time, the motor driving the take-up roller is started. The take-up roller rotates at a set tension or speed, starting to pull and wind the stitched metal roll, thereby realizing continuous and automated material transfer and collection.

[0065] The stitched metal roll provided in this application is a continuous strip material formed by connecting a first metal roll 100 and a second metal roll 200 through any of the aforementioned method embodiments. For example... Figure 7 As shown, its core feature lies in the unique composite structure of the connection area (mechanical interlocking structure and spot welding structure).

[0066] In the connection area of ​​the stitched metal coils, the first end 101 of the first metal coil 100 and the second end 201 of the second metal coil 200 are joined by a mechanical interlocking structure. Specifically, at least one pair (usually multiple pairs) of complementary first insertion portions 1011 and second insertion portions 2011 interlock and lock with each other. These insertion portions are stamped, independent protrusions, preferably designed with a difference in width between the insertion section and the locking section, achieving a strong three-dimensional interlock. This structure continuously provides basic tensile and shear strength in the finished product.

[0067] On the surface of the upper first end 101, there are multiple weld points 400. These weld points penetrate the upper metal layer and fuse the first end 101 and the lower second end 201 together at the weld nugget position to form a metallurgical bond.

[0068] The stitched metal coil of this application, through the synergistic effect of mechanical interlocking and multi-point penetration welding, enables the joint to withstand extremely high longitudinal tensile forces, shear forces, and alternating fatigue loads, with strength far exceeding that of joints using single connection methods (such as pure spot welding or pure riveting). Pre-emptive mechanical locking ensures no relative displacement between plates during welding, and coupled with possible subsequent flattening processes, results in uniform thickness and a smooth surface in the joint area. During high-speed continuous operation (such as coating, stamping, etc.), joint issues will not cause sudden tension changes or material misalignment. Therefore, the stitched metal coil of this application is less prone to problems such as seam cracking, strip breakage, or edge cracking during subsequent production processes, thereby improving the production efficiency and stability of the unit.

[0069] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0070] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0071] Although preferred embodiments have been described in this specification, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this specification.

[0072] Obviously, those skilled in the art can make various modifications and variations to this specification without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, this specification is also intended to include such modifications and variations.

Claims

1. A metal stitching method, characterized in that, include: The first end of the first metal roll is overlapped with the second end of the second metal roll to form an overlap structure; The upper and lower punches are activated to punch the overlapping structure to form at least one first insertion portion on the first end and at least one second insertion portion on the second end, wherein the first insertion portion and the second insertion portion are configured as complementary structures that can be inserted into each other. Pull the first metal roll and the second metal roll in opposite directions respectively, so that the second plug portion located below inserts into the first plug portion located above and locks in place, thereby forming a mechanically interlocking metal roll assembly; Based on the mechanically interlocked metal roll assembly, spot welding is performed at multiple locations on the first end located above to obtain a stitched metal roll; The spot welding energy of each weld point is controlled to penetrate the first end so that the weld point fuses the first end with the second end located below.

2. The metal stitching method according to claim 1, characterized in that, Each solder joint has a solder joint distance from the edge of the first end, and the solder joint distance is greater than a preset distance.

3. The metal stitching method according to claim 1, characterized in that, Both the first and second plug-in portions are protruding structures formed by stamping on their respective metal coils, and in the width direction of the metal coil, both sides of each protruding structure are disconnected from the metal coil body.

4. The metal stitching method according to claim 3, characterized in that, Both the first insertion part and the second insertion part include an insertion section and a locking section that are connected end to end; The insertion section has a first width in the lateral direction of insertion, and the locking section has a second width in the lateral direction of insertion, wherein the first width is smaller than the second width.

5. The metal stitching method according to claim 4, characterized in that, The upper and lower punches are activated to stamp the overlapping structure, specifically including: The upper and lower punches are activated to move towards each other and simultaneously punch the overlapping structure.

6. The metal stitching method according to claim 1, characterized in that, Based on the metal coil assembly, spot welding is performed at multiple locations on the upper first end, specifically including: Based on the metal roll assembly, at least two spot welding operations are performed on the first end located at the top, and the positions of the weld points of different batches of spot welding operations are staggered from each other along the width direction of the metal roll.

7. The metal stitching method according to claim 1, characterized in that, The metal stitching method further includes: Based on the stitched metal roll, continuous welding is performed along the mating edge of the first metal roll and the second metal roll so that the side of the first metal roll is connected to the body of the second metal roll by a weld.

8. The metal stitching method according to claim 1, characterized in that, The metal stitching method further includes: based on the stitched metal roll, activating a flattening roller to flatten the stitched structure.

9. The metal stitching method according to claim 1, characterized in that, When the first metal roll or the second metal roll is fixed on the take-up roller, the metal stitching method further includes: activating the take-up roller to take up the stitched metal roll.

10. A stitched metal roll, characterized in that, The stitched metal roll is obtained by stitching the first metal roll and the second metal roll together using the metal stitching method according to any one of claims 1 to 9.

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