Assembly line system for construction of B-type cabin middle assembly sheet bodies

Abstract

The invention provides an assembly line system for building a B-type cabin middle group sheet body. The assembly line system comprises a feeding unit, a laser cleaning and scribing unit, a friction stir welding plate splicing unit, a ray detection unit, an assembling and welding unit and a discharging unit which are connected in sequence. During construction, the bottom plate plates for splicing the bottom plate are hoisted to an assembly line one by one, the laser cleaning and scribing unit is used for cleaning and polishing a welding bead and scribing various mounting line indication lines, then the friction stir welding plate splicing unit is used for carrying out butt joint on the bottom plate plates one by one according to a plate splicing sequence, and the bottom plate of a middle group sheet body is synthesized; a butt welding seam of a bottom plate is subjected to flaw detection of the ray detection unit and then flows to the assembling and welding unit, T rows and rib plates are subjected to falling assembly according to the positions of an installation line and an indication line through the assembling and welding unit, fillet weld arc welding is carried out after assembly is completed, and finally discharging of a whole middle-group sheet body is carried out through the discharging unit.

Description

Technical Field

[0001] This invention relates to the field of liquefied gas carrier manufacturing, and in particular to a production line system for constructing B-type compartment hulls. Background Technology

[0002] Large LNG carriers, as a crucial link in LNG transportation, are the maritime lifeline of the LNG supply chain. With the continuous growth in LNG transportation demand, shipyards are facing higher requirements for the efficiency and quality of LNG cargo tank construction. The mid-section hull is an intermediate product of the Type B tank; after completion, the mid-section hull is assembled to form the complete Type B tank. Traditionally, the construction of the mid-section hull for Type B tanks relies primarily on manual labor, resulting in dispersed sites, long occupancy periods, low site utilization, and low production efficiency. To improve the construction efficiency and quality of the mid-section hull, the workflow and methods have been restructured. A new assembly line approach has been adopted, employing laser cleaning of weld beads, friction stir welding of plates, and online radiographic testing to replace the original manual operation mode. After the assembly and welding of T-sections and ribs, qualified mid-section hulls are finally produced. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the present invention provides a production line system for the construction of modular panels in a B-type cabin. The production line system includes a loading unit, a laser cleaning and scribing unit, a friction stir welding panel assembly unit, a radiographic inspection unit, an assembly and welding unit, and a unloading unit connected in sequence.

[0004] The middle unit includes a base plate, ribs, T-rows, and elbows. The T-rows and ribs are vertically fixed to the surface of the base plate. Multiple T-rows are arranged along a first direction, and multiple ribs are arranged along a second direction. The first direction is perpendicular to the second direction, and the ribs intersect the T-rows perpendicularly. The bottom edge of the ribs is provided with slots for the T-rows to pass through.

[0005] The base plates used for assembling the base plate are hoisted onto the production line one by one by the feeding unit. First, the weld seams are cleaned and ground, and various installation line indicators are marked by the laser cleaning and marking unit. Then, the base plates are joined one by one according to the assembly sequence by the friction stir welding assembly unit to form the base plate of the middle assembly body. After the bottom plate butt welds are inspected by the radiographic inspection unit, they are transferred to the assembly and welding unit. The assembly and welding unit is equipped with T-row buffer area and rib plate buffer area. The T-row and rib plates are positioned and assembled according to the installation lines and indicator lines by the assembly and welding unit. After assembly, the fillet welds are arc welded. Finally, the entire middle assembly body is unloaded by the unloading unit.

[0006] Optionally, the loading unit, laser cleaning and scribing unit, friction stir welding assembly unit, and radiographic inspection unit are handed over to each other via roller conveyor lines, while the radiographic inspection unit, assembly and welding unit, and unloading unit are handed over to each other via RGV rail conveyor vehicles. All units operate in a single-line flow from front to back.

[0007] Optionally, the loading unit includes a gantry main unit, a ground rail, and suction cup hangers. The ground rail can drive the entire gantry main unit and the suction cup hangers installed on the gantry main unit to move synchronously along the rail direction. The suction cup hangers are arranged in a matrix manner, which can lift base plates of different specifications.

[0008] Optionally, the laser cleaning and scribing unit includes a first roller conveyor, a wire brush grinding device, and a cleaning and scribing main unit. The first roller conveyor is used for conveying and coarse positioning of the base plate. The wire brush grinding device is located below the first roller conveyor and is driven by a linear guide rail to perform linear grinding on the joint area of ​​the base plate. A laser cleaning head and a scribing head are configured above the cleaning and scribing main unit for cleaning and scribing the upper surface of the plate.

[0009] Optionally, the friction stir welding (FSW) assembly unit includes a FSW main unit, a servo carriage, a omnidirectional ball platform, and a second roller conveyor. The FSW main unit is used for key-clamping and fixing of the base plate, CNC milling, weld assembly inspection, FSW positioning welding, FSW formal welding, and post-weld milling of the flash, thereby assembling and welding the base plate into a complete base plate. The servo carriage is divided into an infeed side and an outfeed side, used for clamping and conveying the base plate and for lateral clamping during FSW welding to prevent the plate from opening. The omnidirectional ball platform is used to reduce friction during plate conveying and positioning, facilitating plate position adjustment and positioning. The second roller conveyor is used for plate conveying.

[0010] Optionally, the X-ray inspection unit includes a X-ray inspection host and a third roller conveyor. The X-ray inspection host is used to drive the X-ray machine and the imaging plate to move synchronously to inspect each weld seam on the base plate. The third roller conveyor is mainly used for base plate conveying, weld seam positioning, and weld seam marking.

[0011] Optionally, the assembly and welding unit includes a multi-hole assembly and welding platform, a T-row buffer area, and a rib plate buffer area. After the base plate is transported to the multi-hole assembly and welding platform, the edges of the base plate are fixed using the multi-hole assembly and welding platform and special fixing fixtures. The T-row is hoisted and fixed at one end using a crane and special assembly fixtures. Then, the rib plates are pulled in one by one using a crane and manual assistance. After the rib plates are pulled in, they are fixed with diagonal braces on both sides. The assembly of the middle group piece is first fixed by spot welding. After the assembly is completed, the middle group piece is welded seam by seam to form a complete middle group piece. The middle group piece is transported to the unloading unit using an RGV rail transport vehicle.

[0012] Optionally, the unloading unit includes an RGV rail conveyor, a conveyor rail, and a modular vehicle; the RGV rail conveyor transports the intermediate unit pieces to the top of the modular vehicle, and then the modular vehicle transports the intermediate unit pieces to the large unit site.

[0013] As described above, this invention provides a production line system for constructing the mid-section of a Type B cabin, comprising a sequentially connected loading unit, a laser cleaning and scribing unit, a friction stir welding assembly unit, a radiographic inspection unit, an assembly and welding unit, and a unloading unit. During construction, the base plates used for assembling the base plate are hoisted onto the production line one by one. First, the laser cleaning and scribing unit cleans and polishes the weld seams and scribes various installation lines and indicators. Then, the friction stir welding assembly unit joins the base plates one by one according to the assembly sequence to form the base plate of the mid-section. After the bottom plate welds are inspected by the radiographic inspection unit, they are transferred to the assembly and welding unit. The assembly and welding unit positions the T-rows and ribs according to the installation lines and indicators. After assembly, fillet welds are arc welded. Finally, the unloading unit discharges the entire mid-section.

[0014] This automated production line system employs laser cleaning technology to grind weld seams, improving weld seam grinding quality and avoiding quality defects caused by incomplete or inadequate grinding in subsequent welding processes. It also utilizes double-sided friction stir welding and online X-ray inspection technology, increasing butt welding speed, weld pass rate, and reducing butt weld deformation. Furthermore, the one-seam-one-inspection process ensures the quality and inspection efficiency of each butt seam in the intermediate unit. This automated production line construction mode saves manufacturing space, jig cycle time, and eliminates a significant amount of transfer and circulation work, thereby improving the construction efficiency and quality stability of the intermediate unit. Attached Figure Description

[0015] Figure 1 The diagram shown is an assembly schematic of the middle component in this invention.

[0016] Figure 2 The diagram shown is a schematic representation of the overall structure of the assembly line system in this invention.

[0017] Figure 3 The diagram shows the structural schematics of areas A and B of the assembly line system in this invention.

[0018] Figure 4 The diagram shows the structural schematics of areas C and D of the assembly line system in this invention.

[0019] Figure 5 The diagram shows the structural schematics of areas E and F of the assembly line system in this invention.

[0020] Component designation explanation

[0021] Base plate 1, rib plate 2, T-row 3, elbow plate 4, suction cup lifting device 11, gantry main unit 12, T-row buffer area 72, rib plate buffer area 73, first roller conveyor 21, wire brush grinding device 22, cleaning and marking main unit 23, friction stir welding main unit 31, servo trolley 32, universal ball platform 33, second roller conveyor 34, X-ray inspection main unit 41, third roller conveyor 42, multi-hole welding platform 51, RGV rail conveyor 61, conveyor track 62, central control room 71, modular vehicle 74. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0023] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0024] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0025] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0026] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] like Figures 1 to 5As shown, the present invention provides a production line system for constructing modular components in a B-type cabin, comprising a feeding unit, a laser cleaning and scribing unit, a friction stir welding assembly unit, a radiographic inspection unit, an assembly and welding unit, and a unloading unit connected in sequence.

[0028] The loading unit, laser cleaning and scribing unit, friction stir welding assembly unit, and radiographic inspection unit are connected via roller conveyor lines. The radiographic inspection unit, assembly and welding unit, and unloading unit are connected via RGV rail conveyor vehicles. All units operate in a single-line flow from front to back. The loading unit, laser cleaning and scribing unit, friction stir welding assembly unit, radiographic inspection unit, assembly and welding unit, and unloading unit are located in areas A, B, C, D, E, and F, respectively.

[0029] The middle assembly includes a base plate 1, ribs 2, T-rows 3, and elbow plates 4. The T-rows 3 and ribs 2 are both vertically fixed to the surface of the base plate 1. Multiple T-rows 3 are arranged along a first direction, and multiple ribs 2 are arranged along a second direction. The first direction is perpendicular to the second direction. The ribs 2 intersect the T-rows 3 perpendicularly. The bottom edge of the ribs 2 has slots for the T-rows 3 to pass through.

[0030] During construction, the base plates used for assembling the base plate are hoisted onto the assembly line one by one by the loading unit. First, the weld seams are cleaned and polished, and various installation / indicator lines are marked, by the laser cleaning and marking unit. Then, the base plates are joined together one by one according to the assembly sequence by the friction stir welding unit to form the base plate 1 of the middle assembly. After the weld seams of base plate 1 are inspected by the radiographic testing unit, they are transferred to the assembly and welding unit. The assembly and welding unit is equipped with a T-row buffer area 72 and a rib plate buffer area 73. The T-row 3 and rib plate 2 are positioned and assembled according to the installation and indicator lines by the assembly and welding unit. After assembly, fillet welds are arc welded. Finally, the entire middle assembly is unloaded by the unloading unit. The coordination between the various units is controlled by the central control room 71.

[0031] The loading unit in Zone A mainly includes a gantry crane 12, a ground rail, and suction cup hangers 11. The suction cup hangers 11 are arranged in a matrix to lift base plates of different specifications. The ground rail drives the entire gantry crane 12 and the suction cup hangers 11 mounted on it to move synchronously along the track, facilitating plate movement and feeding in the X-direction. The gantry crane is equipped with a trolley movement mechanism; lifting in the Z-direction is achieved using a stepper motor + rack and pinion + guide rail, and lateral movement in the Y-direction is achieved using a stepper motor + guide rail. This allows for easy adjustment of the suction cup hangers relative to the gantry crane in the Y / Z directions, thereby adjusting the position of the plates. The loading unit in Zone A lifts the plates one by one according to the plate assembly sequence, placing them stably on the first roller conveyor 21 of the laser cleaning and marking unit.

[0032] The laser cleaning and scribing unit in Zone B mainly includes a first roller conveyor 21, a wire brush grinding device 22, and a cleaning and scribing main unit 23. The first roller conveyor 21 primarily transports and roughly positions the base plate. After longitudinal and transverse positioning, a pneumatic pressure arm device secures the base plate, preventing positional shift during wire brush grinding. The wire brush grinding device 22, located below the first roller conveyor, is driven by a linear guide to grind the joint areas of the base plate in a straight line, simultaneously removing dust to prevent environmental pollution. Multiple high-definition cameras are mounted above the cleaning and scribing main unit 23 to photograph and precisely position the plate outline, then match it with standard part outlines in a database to determine the cleaning and scribing positions. A laser cleaning head and a scribing head are mounted above the cleaning and scribing main unit 23, arranged in a line. After cleaning the upper surface of the plate, scribing is performed immediately, with dust removal occurring simultaneously. The sheet metal is hoisted onto the first roller conveyor for rough positioning and fixation. Then, the bottom is ground with a wire brush and the top surface is cleaned with a laser. The cleaning and grinding area is the joint area. The sheet metal is then conveyed forward by the first roller conveyor to another joint area above the wire brush grinding device for rough positioning and fixation. A camera is then used for fine positioning of the sheet metal. The joint area is then ground with a wire brush and the top surface is cleaned with a laser. The internal area of ​​the sheet metal is cleaned with a laser and marked with inkjet according to the corresponding installation lines and indicator lines. After the operation is completed, the pressure arm device is released, and the first roller conveyor continues to convey sheet metal to the friction stir welding assembly unit in area C.

[0033] The friction stir welding (FSW) panel assembly unit in Zone C mainly includes a FSW main unit 31, a servo carriage 32, a omnidirectional ball platform 33, and a second roller conveyor 34. The FSW main unit 31 is the key component of this unit, used for key-clamping and fixing of the base plate, CNC milling, weld assembly inspection, FSW positioning welding, FSW formal welding, and post-weld milling of flash. The servo carriage 32 is divided into an infeed side and an outlet side, used for clamping and conveying the base plate and for lateral clamping during FSW welding to prevent the plate from opening. The omnidirectional ball platform 33 is mainly used to reduce friction during plate conveying and positioning, facilitating plate position adjustment and positioning. The second roller conveyor 34 is used for plate conveying and is divided into an infeed side and an outlet side. After the first base plate arrives at the friction stir welding (FSW) assembly unit in Zone C, it is conveyed by the second roller conveyor and servo carriage on the feeding side. Upon reaching the FSW host 31, the plate is transferred to the discharge side by the servo carriage, where it is then conveyed and positioned. Finally, it is secured using the key-type clamping mechanism within the FSW host 31. The remaining plates are conveyed and positioned by the second roller conveyor and servo carriage on the feeding side, and then secured using the key-type clamping mechanism within the host. After clamping, the plates are milled on both sides using CNC milling within the host to ensure the straightness of the mating edges. The key-type clamping mechanism is then released, and the servo carriage continues to feed the plates to the host for assembly. After assembly, the laser tracking system within the host performs weld seam inspection, checking for gaps and misalignments. Once the assembly inspection is passed, FSW positioning welding is performed, followed by formal FSW welding. During formal welding, the edges are milled simultaneously on both sides. After a single weld is completed, the weld is switched until the entire base plate is assembled. Then, the entire base plate is transferred to the X-ray inspection unit via a servo trolley and the second roller conveyor.

[0034] The X-ray inspection unit in Zone D mainly includes an X-ray inspection host 41 and a third roller conveyor 42. The X-ray inspection host 41 uses X-ray imaging technology to photograph weld seams. A gantry frame drives the X-ray machine and imaging plate to move synchronously to inspect each weld seam on the base plate, detecting defects such as porosity, looseness, inclusions, and cracks. The third roller conveyor 42 is mainly used for base plate transport, weld seam positioning, and weld seam marking. After the base plate flows to the X-ray inspection unit in Zone D, the third roller conveyor is used to transport and position the first weld seam. After the weld seam stops in the X-ray inspection area, the X-ray machine and imaging plate on the host move to the end of the weld seam to prepare for flaw detection. The base plate remains stationary, while the X-ray machine and imaging plate move continuously in one direction at fixed distances, taking one X-ray image with each movement until the end of the weld seam is reached. After the first weld seam is inspected, the X-ray machine and imaging plate return to the starting point, and then the third roller conveyor is used to switch weld seams, completing the flaw detection inspection of all weld seams on the base plate. The results of the flaw detection are manually evaluated to detect weld defects. The defect locations are manually marked, and repairs are carried out in the subsequent large-scale assembly stage. The flaw-detected base plate is transported to the E-zone assembly and welding unit using an RGV rail transport vehicle 61.

[0035] The assembly and welding unit in Zone E mainly includes a multi-hole welding platform 51, a T-row buffer area 72, and a rib plate buffer area 73. The T-row buffer area 72 and rib plate buffer area 73 primarily buffer upstream materials, respectively buffering the T-rows and rib plates required for the intermediate assembly pieces. After the base plate is transported to the multi-hole welding platform 51, its edges are fixed using the platform and specialized fixtures, effectively reducing deformation during subsequent welding processes. Using a crane and specialized assembly fixtures, the T-rows are hoisted and fixed at one end. Then, with the crane and manual assistance, each rib plate is pulled in one by one. After the rib plates are pulled in, diagonal braces are applied on both sides to prevent tipping. After all rib plates for an intermediate assembly piece have been pulled in, they are spot-welded together to complete the assembly of the intermediate assembly piece. After assembly, each weld seam is welded. Flat fillet welds are welded using a fillet welding machine, while vertical welds and corner welds are welded manually using a handheld welding gun. After the entire middle assembly is welded, the middle assembly is transported to the unloading unit in area F using an RGV rail transport vehicle 61.

[0036] The unloading unit in Zone F mainly includes an RGV rail conveyor 61, a conveyor rail 62, and a modular vehicle 74. Before unloading the intermediate sheet, the modular vehicle 74 needs to travel to a designated position in advance. Then, the RGV rail conveyor 61 transports the intermediate sheet onto the modular vehicle 74 to prevent collisions between the modular vehicle and the RGV rail conveyor. The RGV rail conveyor 61 has a lifting function, slowly placing the intermediate sheet onto the modular vehicle, which then transports the intermediate sheet to the main assembly area.

[0037] In summary, this invention provides a production line system for constructing the mid-section of a Type B cabin, comprising a sequentially connected loading unit, a laser cleaning and scribing unit, a friction stir welding assembly unit, a radiographic inspection unit, an assembly and welding unit, and a unloading unit. During construction, the base plates used for assembling the base plate are hoisted onto the production line one by one. First, the laser cleaning and scribing unit cleans and polishes the weld seams and scribes various installation lines and indicators. Then, the friction stir welding assembly unit joins the base plates one by one according to the assembly sequence to form the base plate of the mid-section. After the butt welds of the base plates are inspected by the radiographic inspection unit, they are transferred to the assembly and welding unit. The assembly and welding unit positions the T-rows and ribs according to the installation lines and indicators. After assembly, fillet welds are arc welded. Finally, the unloading unit unloads the entire mid-section.

[0038] This automated production line system employs laser cleaning technology to grind weld seams, improving weld seam grinding quality and avoiding quality defects caused by incomplete or inadequate grinding in subsequent welding processes. It also utilizes double-sided friction stir welding and online X-ray inspection technology, increasing butt welding speed, weld pass rate, and reducing butt weld deformation. Furthermore, the one-seam-one-inspection process ensures the quality and inspection efficiency of each butt seam in the intermediate unit. This automated production line construction mode saves manufacturing space, jig cycle time, and eliminates a significant amount of transfer and circulation work, thereby improving the construction efficiency and quality stability of the intermediate unit.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A flow line system for the construction of a panel in a B-type cabin, characterized in that, The pipeline system comprises sequentially connected feeding unit, laser cleaning and scribing unit, friction stir welding plate assembly unit, ray detection unit, assembly and welding unit, and discharging unit. The middle group plate body comprises a bottom plate, a rib plate, and a T row and an elbow plate, the T row and the rib plate are vertically fixed to the surface of the bottom plate, a plurality of T rows are arranged along a first direction, a plurality of rib plates are arranged along a second direction, the first direction is perpendicular to the second direction, the rib plate and the T row are perpendicular to each other, and a groove hole is formed in the bottom edge of the rib plate for the T row to pass through. The bottom plate plate material for assembling the bottom plate is hoisted to the pipeline by the feeding unit, is cleaned and polished by the laser cleaning and scribing unit, and is scribed with various installation line indicating lines, then is butted according to the plate assembly sequence by the friction stir welding plate assembly unit, and is synthesized into the bottom plate of the middle group plate body, the bottom plate butt joint weld is detected by the ray detection unit, and then is transferred to the assembly and welding unit, the assembly and welding unit is provided with a T row buffer area and a rib plate buffer area, the T row and the rib plate are positioned and assembled according to the installation line and the indicating line position by the assembly and welding unit, after assembly, fillet welding is performed, and finally, the whole middle group plate body is discharged by the discharging unit.

2. The flowline system of building B-type mid-body sections according to claim 1, characterized in that: The feeding unit, the laser cleaning and scribing unit, the friction stir welding plate assembly unit, and the ray detection unit are connected by a roller conveyor line, the ray detection unit, the assembly and welding unit, and the discharging unit are connected by an RGV track conveyor, and all the units perform single-line flow operation from front to back.

3. The flow line system of building B-type midship modules according to claim 1, characterized in that: The feeding unit comprises a gantry main machine, a ground rail, and a suction cup lifting appliance, the ground rail can drive the whole gantry main machine and the suction cup lifting appliance mounted on the gantry main machine to move synchronously along the track direction, the suction cup lifting appliance is arranged in a matrix manner and can hoist different specifications of bottom plate plate materials.

4. The flow line system of building B-type midship modules according to claim 1, wherein: The laser cleaning and scribing unit comprises a first roller line, a steel wire brush polishing device, and a cleaning and scribing main machine, the first roller line is used for conveying and roughly positioning the bottom plate plate material, the steel wire brush polishing device is located below the first roller line, the whole steel wire brush polishing device is driven by a linear guide rail to polish the joint area of the bottom plate plate material in a straight line, and the cleaning and scribing main machine is provided with a laser cleaning head and a scribing head above, and is used for cleaning and scribing the upper surface of the plate material.

5. The flow line system of building B-type midship modules according to claim 1, wherein: The friction stir welding plate assembly unit comprises a friction stir welding main machine, a servo trolley, a universal ball platform, and a second roller line, the friction stir welding main machine is used for piano key pressing and fixing of the bottom plate plate material, CNC edge milling, weld assembly detection, FSW positioning welding, FSW formal welding, and post-welding fly edge milling, so as to assemble and weld the bottom plate plate material into a complete bottom plate, the servo trolley is divided into an inlet side and an outlet side, is used for clamping and conveying the bottom plate plate material, and laterally presses tightly during stirring and welding, so as to prevent the plate material from being opened; the universal ball platform is used for reducing friction during plate material conveying and positioning, facilitating plate material position adjustment and positioning; and the second roller line is used for plate material conveying.

6. The flow line system of building B-type midship modules according to claim 1, wherein: The ray detection unit comprises a ray detection main machine and a third roller line, the ray detection main machine is used for driving the ray machine and the imaging plate to move synchronously to detect each weld of the bottom plate, and the third roller line is mainly used for bottom plate conveying, weld positioning, and weld marking.

7. The flow line system of building B-type midship modules according to claim 1, wherein: The assembling and welding unit comprises a multi-hole assembling and welding platform, a T-row buffer area and a rib plate buffer area; after the bottom plate is conveyed to the multi-hole assembling and welding platform, the edge of the bottom plate is fixed by using the multi-hole assembling and welding platform and a special fixing tool; T-row hoisting and one end of the T-row are fixed by using a crane and a special assembling tool, then the rib plates are pulled in one by one by using the crane and manual assistance, after the rib plates are pulled in, the two sides are fixed by using inclined struts, the assembling of the middle group plate body is completed by spot welding, and the complete middle group plate body is formed by welding each weld, and the middle group plate body is conveyed to the unloading unit by using an RGV track conveying vehicle.

8. The flow line system of building B-type midship modules according to claim 1, wherein: The unloading unit comprises an RGV track conveying vehicle, a conveying vehicle track and a module vehicle; the middle group plate body is conveyed to the top of the module vehicle by using the RGV track conveying vehicle, and then the middle group plate body is conveyed to a large group site by using the module vehicle.

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