Transition plate welding method and system for welding thick galvanized plate of rewinding unit

Abstract

The invention belongs to the technical field of strip steel continuous production, and relates to a transition plate welding method and system for heavy gauge galvanized plate welding of a recoiling unit, the system obtains specification parameters of a forward galvanized plate and a backward galvanized plate through a data obtaining module, calls a transition plate parameter library, and selects a non-plating low-carbon steel transition plate body; the process parameter optimization module calculates and outputs the optimal size parameter of the transition plate based on the median transition principle; the first welding control module is used for controlling positioning, clamping, shearing, centering and welding operation in the first welding process; the middle positioning control module is used for controlling the positioning and preparation work of the rear end of the transition plate and the head of the subsequent galvanized plate; the second welding control module is used for controlling clamping, shearing, centering and welding operation in the second welding process; and the post-welding treatment module is used for equipment resetting, loop control and establishment and adjustment of whole-line tension after welding is completed. The welding seam quality can be effectively improved, and the safety risk is reduced.

Description

A method and system for welding transition plates for thick galvanized steel sheets in rewinding units. Technical Field

[0001] This invention relates to the field of continuous strip steel production technology, specifically to a transition plate welding method and system for welding thick galvanized steel sheets in rewinding units. Background Technology

[0002] Welding of galvanized steel strip is a critical process in cold rolling and recoiling continuous production lines, and its quality directly affects production efficiency and product qualification rate. When directly welding galvanized sheets using narrow lap roll resistance welding, the melting point of the zinc layer is much lower than that of the steel base, which easily leads to a series of problems such as preferential evaporation of the zinc layer, weld porosity, and zinc powder adhesion on the welding wheel surface, which seriously affect welding quality and equipment stability.

[0003] The prior art discloses a welding device and welding method for galvanized strip steel, which adopts a scheme of two welding processes combined with real-time cleaning of the welding wheel by an online milling cutter: the first welding uses low energy parameters to volatilize the zinc layer in the overlapping area and expose the iron base, while the zinc layer on the surface of the welding wheel is removed by a high-speed rotating milling cutter; the second welding is a formal welding of the exposed iron base in the same area.

[0004] This technology has made some progress in suppressing zinc layer interference and realizing direct welding of galvanized sheets, but the following technical problems still exist: The above solutions are mostly for thin strip steel (≤1.8mm), while for thick galvanized sheets, there are problems such as poor welding quality, large welding wheel wear, and high risk of strip breakage in the rewinding unit.

[0005] In view of this, it is very necessary to provide a transition plate welding method and system for welding thick galvanized sheets in rewinding units, so as to solve the above-mentioned defects in the prior art. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of poor welding quality, high welding wheel wear, and high risk of strip breakage in the prior art for thick galvanized sheets in rewinding units. The invention provides a transition plate welding method and system for welding thick galvanized sheets in rewinding units to solve the technical problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Firstly, the present invention provides a method for welding a transition plate for welding thick-gauge galvanized sheets in a rewinding unit, comprising the following steps: Step S1: Obtaining the dimensional parameters of the preceding and following galvanized sheets, and preparing an uncoated low-carbon steel transition plate as the transition plate body; Step S2: Based on the median transition principle, optimizing the thickness, width, and length of the transition plate body to match the specifications of the galvanized sheets; Step S3: Positioning the tail of the preceding galvanized sheet and the front end of the transition plate body within the welding machine shear box area. After positioning, clamping, shearing, and centering, perform narrow lap roll resistance welding to form the first weld; Step S4: Position the rear end of the welded transition plate body to the shear box area, and simultaneously position the head of the subsequent galvanized sheet strip to the same area to prepare for the second welding; Step S5: After clamping, shearing, and centering the rear end of the transition plate body and the head of the subsequent galvanized sheet strip, perform narrow lap roll resistance welding to form the second weld; Step S6: After welding is completed, reset the welding machine equipment, use jogging operation to drop the looper, establish tension along the entire line, and resume continuous production of the unit.

[0008] Secondly, the present invention also provides a transition plate welding control system for welding thick-gauge galvanized sheets in a rewinding unit, comprising: a data acquisition module for acquiring the specification parameters of the preceding and following galvanized sheets, and calling the transition plate parameter library to select an uncoated low-carbon steel transition plate body; a process parameter optimization module for calculating and outputting the optimal dimensional parameters of the uncoated low-carbon steel transition plate body based on the median transition principle; a first welding control module for controlling the positioning, clamping, shearing, alignment, and welding operations during the first welding process; an intermediate positioning control module for controlling the positioning and preparation of the rear end of the uncoated low-carbon steel transition plate body and the leading edge of the following galvanized sheet; a second welding control module for controlling the clamping, shearing, alignment, and welding operations during the second welding process; and a post-weld processing module for equipment reset, looper control, and the establishment and adjustment of tension throughout the entire line after welding.

[0009] The modules work together to achieve a high-quality welded connection between the galvanized sheet and the transition plate, improving the first-pass welding qualification rate to over 98%, reducing the risk of strip breakage and welding wheel wear, and ensuring continuous, safe and efficient production of the rewinding unit.

[0010] The beneficial effects of this invention are as follows: by introducing an uncoated low-carbon steel transition plate as the transition plate body between two thick galvanized sheets, and obtaining the dimensional parameters of the preceding and following galvanized sheets before welding, the welding area avoids the adverse effects of the galvanized layer on the roll resistance weld, thereby improving the problem of poor welding quality that easily occurs when directly welding thick galvanized sheets, and improving the stability of weld formation. For welding scenarios of thick galvanized sheets (>1.8mm), the buffering effect of the transition plate avoids weld defects caused by current concentration during thick plate welding, further reducing the risk of strip breakage.

[0011] This invention optimizes the thickness, width, and length of the transition plate body based on the median transition principle, so that the transition plate body forms a smooth transition with the preceding and following galvanized plates in terms of size and rigidity, reducing sudden changes in current and pressure during welding, reducing abnormal wear of the welding wheel when welding thick galvanized plates, and thus extending the service life of the welding wheel.

[0012] This invention employs narrow-lap roll resistance welding between the tail of the preceding galvanized steel strip and the front end of the transition plate body, and between the rear end of the transition plate body and the head of the following galvanized steel strip. This makes the welding object of each weld more singular and the welding conditions more stable, effectively reducing welding defects such as spatter, incomplete welding, and incomplete penetration, and improving the overall welding quality.

[0013] This invention completes the positioning, clamping, shearing, and centering operations of galvanized sheets and transition plates within the shearing area of ​​the welding machine, ensuring the consistency of weld position and overlap, avoiding uneven stress on the weld joint, and thus reducing the risk of cracking and breakage of the weld during subsequent operation.

[0014] After welding is completed, this invention resets the welding machine and establishes full-line tension, enabling the unit to smoothly return to continuous production. This avoids the weld from operating under abnormal tension or impact loads, further improving the reliability of the weld in the rewinding unit. The transition plate body has no zinc layer on its surface, avoiding zinc powder adhesion to the welding wheel surface and the abnormal wear caused by it, thus reducing welding wheel wear.

[0015] This invention replaces the direct welding of thick galvanized sheets with a transition plate welding method, effectively solving the problem of poor welding stability of thick galvanized sheets in existing technologies for rewinding units while ensuring continuous production. This invention utilizes the excellent welding performance of low-carbon steel, increasing the first-pass welding qualification rate to over 98% and improving weld quality; it reduces zinc powder contamination, extends welding wheel life by approximately 50%, and reduces welding wheel consumption; it improves operational safety, reduces the number of strip breaks, and lowers safety risks.

[0016] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 is a flowchart of a transition plate welding method for welding thick galvanized steel sheets in a rewinding unit; Figure 2 is a schematic block diagram of a transition plate welding system for welding thick galvanized steel sheets in a rewinding unit. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following implementation methods.

[0020] Example 1: As shown in Figure 1, this example provides a method for welding a transition plate for welding thick galvanized sheets in a rewinding unit, including the following steps: Step S1: Obtain the specification parameters of the preceding and following galvanized sheets, and prepare an uncoated low-carbon steel transition plate as the transition plate body; Step S2: Based on the median transition principle, optimize the thickness, width, and length of the transition plate body to match the specifications of the galvanized sheets; Step S3: Position, clamp, and shear the tail of the preceding galvanized sheet and the front end of the transition plate body within the welding machine shear box area. After cutting and centering, perform narrow lap roll resistance welding to form the first weld; Step S4: Position the rear end of the welded transition plate body to the shear box area, and simultaneously position the head of the subsequent galvanized sheet strip to the same area to prepare for the second welding; Step S5: After clamping, cutting, and centering the rear end of the transition plate body and the head of the subsequent galvanized sheet strip, perform narrow lap roll resistance welding to form the second weld; Step S6: After welding is completed, reset the welding machine, use jogging operation to drop the looper, establish tension along the entire line, and resume continuous production of the unit.

[0021] In step S1: the specifications of the preceding and following galvanized sheets are obtained to provide a basis for subsequent welding processes; the thickness of the preceding and following galvanized sheets is 1.5mm to 2.5mm, and the width is 1000mm to 1800mm.

[0022] To ensure reliable welding of medium-thick galvanized sheets in the rewinding unit, a transition plate body is used as a welding transition device. The transition plate body is made of uncoated low-carbon steel, specifically DC01 grade uncoated low-carbon cold-rolled steel sheet conforming to EN 10130 standard. The dimensions of the uncoated low-carbon steel structure meet the requirements of thickness 1.8mm~2.2mm, width 1300mm~1500mm, and length 500mm~700mm. Before welding, the transition plate body undergoes surface treatment to remove oil, rust, scale, and other impurities to ensure the cleanliness of the welding interface and the welding quality.

[0023] In step S2: Based on the median transition principle, the thickness, width and length of the transition plate body are optimized to form a smooth transition with the preceding and following galvanized plates in terms of geometric dimensions and welding performance.

[0024] For the preceding and following galvanized sheets with a thickness of 1.5mm to 2.5mm and a width of 1000mm to 1800mm, the dimensions in the middle range of this range are selected as the design benchmark for the transition plate body. By using a median range of 1.8mm to 2.2mm in the thickness direction, a median range of 1300mm to 1500mm in the width direction, and a reasonable transition length of 500mm to 700mm in the length direction, the transition plate achieves a progressive dimensional match with the galvanized sheet when entering the welding area.

[0025] Based on the median transition principle, the transition plate body is selected with a thickness of 2.0mm (±0.1mm), a width of 1400mm (±10mm), and a length of 600mm (±50mm). This size is located in the median range of the specifications of the preceding and following galvanized plates, which can take into account the welding stability of both thin and thick galvanized plates during the welding process.

[0026] The transition plate body is optimized by adopting the median transition principle, so that the welding current distribution, welding pressure and heat input are more uniform, avoiding welding instability, weld strength fluctuation or abnormal wear of welding wheel due to excessive size difference.

[0027] In step S3: the tail of the galvanized sheet is accurately stopped in the welding machine shear box area along the center line of the unit by the unit control method, and the transition plate body is transported to the welding machine entrance side along the center line of the unit, and the front end of the transition plate body is placed in the shear box area, so that the tail of the galvanized sheet and the front end of the transition plate body are initially positioned at the same welding station; wherein, the shear box area is the shear area of ​​the welding machine.

[0028] After positioning, use the inlet and outlet clamp press buttons on the welding machine's control panel to clamp and fix the transition plate body and the preceding galvanized sheet along the unit's centerline. Then, press the shear button on the control panel to activate the double-blade shears, simultaneously shearing the tail of the preceding galvanized sheet and the front end of the transition plate body to remove irregular ends and obtain a flat, clean weldable section. After shearing, based on the width alignment of the transition plate body and the preceding galvanized sheet, press the longitudinal alignment button on the control panel to finely adjust them longitudinally along the unit's centerline towards the operating or transmission side, ensuring good alignment in the welding direction.

[0029] After completing the alignment adjustment, press the exit clamp tilt button, inlet clamp feed button, and exit clamp drop button on the welding machine operation panel to control the exit clamp tilt, inlet clamp feed, and exit clamp reset, so that the front end of the transition plate body and the tail of the preceding galvanized sheet strip enter the welding position. Then, press the welding start button on the welding machine operation panel to start the welding program along the unit centerline, using the narrow lap roll resistance seam welding method. During the welding process, the welding wheel rolls along the welding direction and simultaneously rolls the weld area, allowing the weld metal to fully fuse and densely form, thereby forming a stable and reliable first weld between the tail of the preceding galvanized sheet strip and the front end of the transition plate body.

[0030] By precisely positioning, clamping, shearing, and centering along the centerline of the unit, the flatness and alignment of the welding end face of the leading galvanized strip and the front end of the transition plate are ensured, thereby improving the density and strength of the weld, reducing welding defects and the risk of strip breakage, and increasing the first-pass yield rate of welding.

[0031] In step S4: After completing the first welding, click the C-shaped trolley home position button on the welding machine operation panel to return to the initial position. Click the lead jog advance button and the jog follow strip button on the welding machine operation panel to position the rear end of the welded transition plate body along the unit center line to the welding machine shear area. At the same time, move the follow galvanized plate along the unit center line to the same area to prepare for the second welding.

[0032] By precisely positioning and simultaneously preparing the transition plate and the subsequent galvanized plate, not only is the flatness and alignment of the welding ends of the two plates ensured, but stable and controllable welding conditions are also provided for the second welding, thereby improving the weld quality and reducing welding defects and the risk of strip breakage.

[0033] In step S5: Confirm that the rear end of the transition plate body and the head of the subsequent galvanized sheet are positioned along the unit's centerline within the welding machine's shearing area. Control the inlet and outlet clamps along the unit's centerline using the inlet and outlet clamp press buttons on the welding machine's operation panel. Jog the head-in button on the welding machine's operation panel; the head of the subsequent galvanized sheet moves towards the welding machine, creating a loop of approximately 300-500mm to ensure balanced tension of the galvanized sheet strip during welding. After clamping and loop formation, press the shear button on the welding machine's operation panel to activate the double-blade shears, cutting off irregular portions of the rear end of the transition plate body and the head of the subsequent galvanized sheet to obtain a flat and clean weld section. Press the longitudinal alignment button on the welding machine's operation panel for fine-tuning, aligning the rear end of the transition plate with the head of the subsequent galvanized sheet along the unit's centerline. After completing the centering adjustment, click the exit clamp tilt button, inlet clamp feed button, and exit clamp drop button on the welding machine operation panel to control the exit clamp tilt, inlet clamp feed, and exit clamp reset, so that the rear end of the transition plate body and the head of the subsequent galvanized sheet enter the welding position. After the welding preparation is completed, click the welding start button on the welding machine operation panel to start the welding machine to perform narrow lap roll resistance welding. The welding wheel rolls along the welding direction and rolls synchronously to ensure that the weld is dense and formed, thus forming the second weld.

[0034] By precisely clamping, shearing, and centering along the unit's centerline, the welded end faces are made flat, aligned, and tensioned evenly, ensuring that the second weld has excellent mechanical strength and density, while reducing welding defects and the risk of strip breakage, and improving the first-pass yield and production continuity.

[0035] In step S6: after completing the second welding to form the second weld, click the C-shaped trolley home position button on the welding machine operation panel to return to the initial position, click the head jog retraction button on the welding machine operation panel to make the looper fall, click the force control tension button on the welding machine operation panel to establish full-line tension and resume continuous production of the rewinding unit; the tension value is set according to the unit control requirements.

[0036] By resetting the welding machine and properly adjusting the looper, the welding equipment is kept in a safe standby state. By establishing tension along the entire line, the galvanized steel strip runs smoothly along the unit, thereby restoring production continuity, avoiding the risk of slippage or breakage of the galvanized steel strip, and improving the safety and production efficiency of the rewinding unit.

[0037] Example 2: As shown in Figure 2, this example provides a transition plate welding system for welding thick galvanized sheets in a rewinding unit. The system includes a data acquisition module 1, which collects incoming material parameters, including thickness, width, and length, of the preceding and following galvanized sheets before welding begins. Based on the collected parameters, it retrieves an uncoated low-carbon steel transition plate body matching the specified range from the transition plate parameter library. Simultaneously, it verifies the specifications and confirms the surface condition of the uncoated low-carbon steel transition plate body. By matching the incoming material parameters with the uncoated low-carbon steel transition plate body parameters before welding, welding instability caused by specification mismatch is avoided, providing a reliable data foundation for subsequent welding processes.

[0038] The process parameter optimization module 2 is used to calculate and filter the thickness, width, and length of the transition plate according to the obtained specifications of the preceding and following galvanized sheets, following the median transition principle. It outputs the body size parameters of the uncoated low-carbon steel transition plate, which lies within the middle range of the preceding and following galvanized sheet specifications. By reducing abrupt changes in geometry and heating conditions between the two welding surfaces, the current distribution and welding pressure during the welding process become more uniform, thereby improving weld formation quality and welding stability.

[0039] The first welding control module 3 is used to complete the positioning, clamping, synchronous shearing, longitudinal alignment, and narrow lap roll resistance welding operations of the tail of the galvanized steel strip and the front end of the uncoated low-carbon steel transition plate body within the shear box area during the first welding process, so that the two form the first weld along the center line of the unit. Through the orderly control of each welding stage, the weld end face is ensured to be flat and accurately aligned, effectively reducing the probability of welding defects and improving the first-pass yield of the first weld.

[0040] The intermediate positioning control module 4 is used to control the rear end of the welded uncoated low-carbon steel transition plate body to enter the shear box area after the first welding is completed, and guide the head of the subsequent galvanized plate to enter the same welding station along the center line of the unit for synchronous positioning and preparation before the second welding. By ensuring the consistency of the uncoated low-carbon steel transition plate body and the subsequent galvanized plate in spatial position, it creates stable conditions for subsequent welding and reduces the risk of repeated adjustments and misoperation.

[0041] The second welding control module 5 is used to perform clamping, shearing, longitudinal alignment, and narrow lap roll resistance welding operations on the rear end of the uncoated low-carbon steel transition plate body and the head of the subsequent galvanized steel strip during the second welding process, forming the second weld. During the welding process, a loop is formed to balance the tension of the galvanized steel strip. Through stable tension control and precise welding alignment, the second weld has good density and mechanical strength, ensuring the continuity and reliability of the entire galvanized steel strip connection.

[0042] The post-weld processing module 6 is used to control the welding equipment to reset after two welding operations, so that the welding mechanism returns to its initial state. Through the looper release and tension establishment operation, the preceding galvanized sheet, the uncoated low-carbon steel transition plate body and the following galvanized sheet form a continuous and stable operating state. By quickly restoring the welding machine working position and establishing reasonable tension throughout the line, the unit is guaranteed to smoothly transition to normal production state, improving production safety and operating efficiency.

[0043] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods disclosed in the embodiments are described simply because they correspond to the systems disclosed in the embodiments; relevant details can be found in the method section.

[0044] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0045] In the embodiments provided by this invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.

[0046] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0047] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit.

[0048] Similarly, in the various embodiments of the present invention, each processing unit can be integrated into a functional module, or each processing unit can exist physically, or two or more processing units can be integrated into a functional module.

[0049] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0050] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply 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 limitations, 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.

[0051] The above-disclosed embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any non-creative variations that can be conceived by those skilled in the art, as well as any improvements and modifications made without departing from the principles of the present invention, should fall within the protection scope of the present invention.

Claims

1. A method for welding transition plates for welding thick galvanized sheets in rewinding units, characterized in that, The process includes the following steps: Step S1: Obtain the specifications of the preceding and following galvanized sheets, and prepare an uncoated low-carbon steel transition plate as the transition plate body; Step S2: Based on the median transition principle, optimize the thickness, width, and length of the transition plate body to match the specifications of the galvanized sheets; Step S3: Position, clamp, shear, and center the tail of the preceding galvanized sheet and the front end of the transition plate body within the shearing area of ​​the welding machine, and then perform narrow lap roll resistance welding to form the first weld; Step S4: Position the rear end of the welded transition plate body to the shearing area, and simultaneously position the head of the following galvanized sheet to the same area to prepare for the second welding; Step S5: Clamp, shear, and center the rear end of the transition plate body and the head of the following galvanized sheet, and then perform narrow lap roll resistance welding to form the second weld; Step S6: After welding is completed, reset the welding machine, use jogging operation to lower the looper, establish full-line tension, and resume continuous production of the unit.

2. The method for welding transition plates for thick galvanized steel sheets in rewinding units according to claim 1, characterized in that, In step S1: the thickness of the preceding galvanized sheet and the following galvanized sheet is 1.5mm to 2.5mm, and the width is 1000mm to 1800mm; a transition plate body is used as a welding transition device. The transition plate body is made of uncoated low carbon steel. Before welding, the transition plate body is surface treated to remove oil, rust, and oxide scale.

3. A method for welding transition plates for thick galvanized steel sheets in rewinding units according to claim 1 or 2, characterized in that, The uncoated low-carbon steel is DC01 grade uncoated low-carbon cold-rolled steel sheet according to EN 10130 standard. The structural dimensions of the uncoated low-carbon steel meet the requirements of thickness 1.8mm~2.2mm, width 1300mm~1500mm, and length 500mm~700mm.

4. The method for welding transition plates for thick galvanized steel sheets in rewinding units according to claim 1, characterized in that, In step S2: Based on the median transition principle, the thickness, width and length of the transition plate body are optimized. The transition plate body is selected with a thickness of 2.0mm, a width of 1400mm and a length of 600mm.

5. The method for welding transition plates for thick galvanized steel sheets in rewinding units according to claim 1, characterized in that, In step S3: the tail of the forward galvanized sheet is accurately stopped within the shear box area of ​​the welding machine along the centerline of the unit using the unit control method. The transition plate body is then transported to the welding machine inlet side along the unit centerline, and the front end of the transition plate body is placed within the shear box area. The tail of the forward galvanized sheet and the front end of the transition plate body are initially positioned at the same welding station. The shear box area is the shear area of ​​the welding machine. The inlet clamp and outlet clamp are pressed down using the inlet clamp and outlet clamp buttons on the welding machine operation panel to clamp and fix the transition plate body and the forward galvanized sheet along the unit centerline. The shearing button on the welding machine operation panel is pressed to start the double-blade shears, which simultaneously shear the tail of the forward galvanized sheet and the front end of the transition plate body. After removing irregular ends and shearing, click the longitudinal alignment button on the welding machine operation panel to finely adjust the longitudinal alignment of the two sides along the center line of the unit towards the operating side or the transmission side. Click the exit clamp tilt button, inlet clamp feed button, and exit clamp drop button on the welding machine operation panel to control the exit clamp tilt, inlet clamp feed, and exit clamp reset, so that the front end of the transition plate body and the tail of the preceding galvanized sheet enter the welding position. Click the welding start button on the welding machine operation panel to start the welding program along the center line of the unit and use the narrow lap rolling resistance seam welding method for welding. During the welding process, the welding wheel rolls along the welding direction and simultaneously rolls the weld area to form the first weld between the tail of the preceding galvanized sheet and the front end of the transition plate body.

6. A method for welding transition plates for thick galvanized steel sheets in a rewinding unit according to claim 5, characterized in that, In step S4: After completing the first welding, click the C-shaped trolley home position button on the welding machine operation panel to return to the initial position. Click the lead jog forward button and the jog backward strip button on the welding machine operation panel to position the rear end of the welded transition plate body along the center line of the unit to the welding machine shear area. At the same time, move the rear galvanized plate along the center line of the unit to the same area.

7. A method for welding transition plates for thick galvanized sheets in rewinding units according to claim 6, characterized in that, In step S5: Confirm that the rear end of the transition plate body and the head of the subsequent galvanized sheet are positioned along the unit's centerline within the welding machine's shearing area. Control the inlet and outlet clamps along the unit's centerline using the inlet clamp press button and outlet clamp press button on the welding machine's operating panel. Then, jog the head-advance button on the welding machine's operating panel; the head of the subsequent galvanized sheet moves towards the welding machine, creating a loop. Finally, press the shearing button on the welding machine's operating panel to activate the double-blade shears, cutting off the remaining material from the rear end of the transition plate body and the head of the subsequent galvanized sheet. In the regular section, obtain a flat and clean weld cross-section; click the longitudinal alignment button on the welding machine operation panel to make longitudinal fine adjustments; click the exit clamp tilt button, inlet clamp feed button and exit clamp drop button on the welding machine operation panel to control the exit clamp tilt, inlet clamp feed and exit clamp reset, so that the rear end of the transition plate body and the head of the subsequent galvanized plate enter the welding position. After the welding preparation is completed, click the welding start button on the welding machine operation panel to start the welding machine to perform narrow lap roll resistance welding. The welding wheel rolls along the welding direction and rolls synchronously to form the second weld.

8. A method for welding transition plates for thick galvanized sheets in rewinding units according to claim 7, characterized in that, In step S6: Click the C-shaped trolley home position button on the welding machine operation panel to return to the initial position; click the head jog retraction button on the welding machine operation panel to lower the loop; click the force control tension button on the welding machine operation panel to establish tension along the entire line and resume continuous production of the rewinding unit; the tension value is set according to the unit control requirements.

9. A transition plate welding system for welding thick galvanized sheets in a rewinding unit, characterized in that, include: The system comprises a data acquisition module (1), a process parameter optimization module (2), a first welding control module (3), an intermediate positioning control module (4), a second welding control module (5), and a post-weld treatment module (6). The data acquisition module (1) acquires the specifications of the preceding and following galvanized plates and calls the transition plate parameter library to select the uncoated low-carbon steel transition plate body. The process parameter optimization module (2) calculates and outputs the optimal size parameters of the uncoated low-carbon steel transition plate body based on the median transition principle. The first welding control module (3) controls the positioning, clamping, shearing, centering, and welding operations during the first welding process. The intermediate positioning control module (4) controls the positioning and preparation of the rear end of the uncoated low-carbon steel transition plate body and the head of the following galvanized plate. The second welding control module (5) controls the clamping, shearing, centering, and welding operations during the second welding process. The post-weld treatment module (6) is used for equipment reset, looper control, and the establishment and adjustment of tension throughout the entire line after welding is completed.

10. A transition plate welding system for welding thick galvanized sheets in a rewinding unit according to claim 9, characterized in that, The data acquisition module (1) is used to collect incoming material parameters, including thickness, width and length, of the preceding and following galvanized sheets before the start of welding operations, and to retrieve uncoated low-carbon steel transition plate bodies that match the specification range from the transition plate parameter library based on the collected results. At the same time, the specifications and surface condition of the uncoated low-carbon steel transition plate bodies are verified. The process parameter optimization module (2) is used to calculate and screen the thickness, width and length of the transition plate according to the obtained specifications of the preceding and following galvanized sheets, and output the size parameters of the uncoated low-carbon steel transition plate bodies that are located in the middle range of the specifications of the preceding and following galvanized sheets. The first welding control module (3) is used to complete the positioning, clamping and fixing, synchronous shearing, longitudinal centering and narrow overlap of the tail of the preceding galvanized sheet and the front end of the uncoated low-carbon steel transition plate body in the shear box area during the first welding process. The rolling resistance welding operation is performed to form the first weld along the center line of the unit. After the first welding is completed, the intermediate positioning control module (4) controls the rear end of the welded uncoated low carbon steel transition plate body to enter the shear box area and guides the head of the galvanized plate to enter the same welding station along the center line of the unit for synchronous positioning and preparation before the second welding. The second welding control module (5) is used to complete the clamping, shearing, longitudinal centering and narrow lap rolling resistance welding operation of the rear end of the uncoated low carbon steel transition plate body and the head of the galvanized plate in the second welding process, and to form a looper and the second weld during the welding process. The post-weld processing module (6) is used to control the welding equipment to reset after the two weldings are completed, so that the welding mechanism returns to the initial state, and through the looper release and tension establishment operation, so that the front galvanized plate, the uncoated low carbon steel transition plate body and the rear galvanized plate form a continuous and stable operating state.

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