A continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes

Abstract

The present invention relates to a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes, belonging to the technical field of straight-seam stainless steel welded pipe production. This device is sequentially provided with an uncoiling device, a steel plate leveling device, a cutting and butt-welding device, a steel plate pressing and guiding device, a rough forming rolling mill unit, a fine forming rolling mill unit, an automatic welding device, an internal and external weld bead leveling device, an online degreasing device, an online solution annealing device, a rough sizing unit, a fine sizing and straightening unit, a length cutting device, an end trimming and flattening device, a quality inspection device for offline products, a ray detection device, a hydrostatic / airtight test device, a pickling and passivation device, an eddy current detector, a finished product inspection device, and a packaging and labeling device according to the production process of large-diameter stainless steel straight-seam welded pipes. The forming device and the preparation method provided by the present invention have a high degree of intelligence and high production efficiency. A set of units can produce stainless steel straight-seam welded pipes of various specifications, reduce production costs, and is conducive to the development and application of straight-seam steel pipe production.

Description

Technical Field

[0001] The present invention belongs to the technical field of the production of straight-seam stainless steel welded pipes, and particularly relates to a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes. Background Art

[0002] Stainless steel straight-seam welded pipes / tubes are made of stainless steel plates by bending and then welding. They are mainly used in many fields with extremely high corrosion resistance requirements such as the petrochemical industry and offshore engineering, and are widely used in aspects such as the petrochemical industry, power industry, and urban construction. They can transport liquids and gases, and can also be used as pipes for piling, bridges, docks, roads, and building structures. However, the existing straight-seam welded pipes have problems such as low intelligence and low production efficiency during the production process. In addition, a set of straight-seam welded pipe production line can only produce welded pipes with the same specification diameter, which not only increases the production cost and the floor area occupied by the equipment, but also seriously hinders the development and application of straight-seam steel pipe production. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes, and a set of units can produce stainless steel straight-seam welded pipes of various specifications.

[0004] The present invention is realized through the following technical solutions.

[0005] A continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes, characterized in that: in accordance with the production process of large-diameter stainless steel straight-seam welded pipes, an uncoiler device, a steel plate leveling device, a cut-end butt welding device, a steel plate pressing and guiding device, a rough forming rolling mill unit, a finish forming rolling mill unit, an automatic welding device, an internal and external weld leveling device, an online degreasing device, an online solution annealing device, a rough sizing unit, a finish sizing and straightening unit, a length cutting device, a trimming and squaring device, a offline quality inspection device, a ray detection device, a hydrostatic / gas tightness test device, a pickling and passivation device, an eddy current detector, a finished product inspection device, and a packaging and marking device are sequentially arranged;

[0006] The steel plate leveling device includes a pinch roll device, a steel plate leveling machine, and a transmission device. The transmission device is arranged on the inlet side of the pinch roll device, the pinch roll device is arranged on the inlet side of the steel plate leveling machine, and the transmission device feeds the uncoiled steel plate into the pinch roll device, and the pinch roll device pinches and feeds the steel plate into the inlet side of the steel plate leveling machine;

[0007] The cut-end butt welding device includes a steel plate centering device I, a cut-end butt welder, and a steel plate centering device II. The steel plate centering device I and the steel plate centering device II are respectively arranged on the corresponding inlet side and outlet side of the cut-end butt welder;

[0008] The rough forming rolling mill set includes at least five rough forming rolling mills arranged in sequence. Each rough forming rolling mill includes a frame, a screw down device, an upper roll and a lower roll. The upper roll and the lower roll are installed on the frame, and the screw down device is installed on the frame and arranged above the upper roll. The screw down device drives the upper roll to move downward. In the rough forming rolling mill set, the roll profiles of each rough forming rolling mill are gradually reduced in diameter.

[0009] Further, the uncoiler includes an uncoiler carriage and an uncoiler. The uncoiler carriage transports the steel coil to be rolled to the inlet position of the uncoiler.

[0010] Further, the steel plate leveling machine includes an upper housing, upper leveling rolls, lower leveling rolls and a lower housing. The upper leveling rolls are installed in the upper housing, the lower leveling rolls are installed in the lower housing, and the steel plate passes through the roll gap between the upper leveling rolls and the lower leveling rolls.

[0011] Further, the finish forming rolling mill set includes a finish forming rolling mill I, a finish forming rolling mill II and a finish forming rolling mill III arranged in sequence. The finish forming rolling mill I is composed of four vertical roll mills.

[0012] Further, the rough sizing mill set includes a rough sizing mill I, a rough sizing mill II, a rough sizing mill III and a rough sizing mill IV arranged in sequence.

[0013] Further, the finish sizing and straightening mill set includes a finish sizing and straightening mill I and a finish sizing and straightening mill II arranged in sequence. Both the finish sizing and straightening mill I and the finish sizing and straightening mill II are provided with four rolls arranged in a cross shape, and the included angle between the roll axes of the two finish sizing and straightening mills is arranged at 45°.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] A continuous intelligent forming device for large-diameter stainless steel straight seam welded pipes provided by the present invention has a high degree of intelligence and high production efficiency. Multiple specifications of stainless steel straight seam welded pipes can be produced by one set of equipment, reducing production costs and being beneficial to the development and application of straight seam steel pipe production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the equipment production line of the present invention;

[0017] Figure 2 is a schematic diagram of the structure of the uncoiler;

[0018] Figure 3 is a front view structural schematic diagram of the steel plate leveling device;

[0019] Figure 4 is Figure 3 a top view structural schematic diagram of;

[0020] Figure 5 Schematic diagram of the structure of the head-cut butt welding device;

[0021] Figure 6 Schematic diagram of the structure of the rough forming rolling mill unit;

[0022] Figure 7 Schematic diagram of the structure of the rough forming rolling mill;

[0023] Figure 8 Schematic diagram of the structure of the upper roll of the rough forming rolling mill;

[0024] Figure 9 Schematic diagram of the structure of the lower roll of the rough forming rolling mill;

[0025] Figure 10 Schematic diagram of the structure of the finish forming rolling mill unit;

[0026] Figure 11 Schematic diagram of the structure of the finish forming rolling mill I;

[0027] Figure 12 Schematic diagram of the structure of the finish sizing and straightening mill unit;

[0028] Figure 13 Schematic diagram of the roll arrangement of the finish sizing and straightening mill I;

[0029] Figure 14 Schematic diagram of the roll arrangement of the finish sizing and straightening mill II;

[0030] In the figure:

[0031] 1 is the uncoiler device, 1.1 is the uncoiler carriage, and 1.2 is the uncoiler;

[0032] 2 is the steel plate leveling device, 2.1 is the pinch roll device; 2.2 is the steel plate leveling machine, 2.2.1 is the upper housing, 2.2.2 is the upper leveling roll, 2.2.3 is the lower leveling roll, 2.2.4 is the lower housing; 2.3 is the transmission device;

[0033] 3 is the head-cut butt welding device, 3.1 is the steel plate centering device I, 3.2 is the head-cut butt welder, and 3.3 is the steel plate centering device II;

[0034] 4 is the steel plate pressing and guiding device;

[0035] 5 is the rough forming rolling mill unit, 5.1 is the rough forming rolling mill I, 5.1.1 is the housing, 5.1.2 is the screwdown device, 5.1.3 is the upper roll, 5.1.4 is the roll; 5.2 is the rough forming rolling mill II, 5.3 is the rough forming rolling mill III, 5.4 is the rough forming rolling mill IV, 5.5 is the rough forming rolling mill V;

[0036] 6 is the finish forming rolling mill unit, 6.1 is the finish forming rolling mill I, 6.2 is the finish forming rolling mill II, 6.3 is the finish forming rolling mill III;

[0037] 7 is an automatic welding device, 8 is an internal and external weld bead leveling device, 9 is an on-line degreasing device, and 10 is an on-line solution treatment device;

[0038] 11 is a rough sizing unit, 11.1 is rough sizing machine I, 11.2 is rough sizing machine II, 11.3 is rough sizing machine III, and 11.4 is rough sizing machine IV;

[0039] 12 is a finish sizing and straightening machine, 12.1 is finish sizing and straightening machine I, 12.1.1 is the roll of finish sizing and straightening machine I; 12.2 is finish sizing and straightening machine II, and 12.2.1 is the roll of finish sizing and straightening machine II

[0040] 13 is a fixed-length shearing device, 14 is an end trimming and flattening device, 15 is an off-line quality inspection device, 16 is a ray detection device, 17 is a hydrostatic / airtight test device, 18 is a pickling and passivation device, 19 is an eddy current detector, 20 is a finished product inspection device, and 21 is a packaging and labeling device. Detailed implementation manners

[0041] The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. Unless otherwise specified, the embodiments are all carried out under conventional experimental conditions. In addition, for those skilled in the art, without departing from the essence and scope of the present invention, various modifications or improvements made to the material components and dosages in these implementation manners all fall within the scope of protection required by the present invention.

[0042] As Figures 1 to 14 shown, a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes, characterized in that: a decoiling device 1, a steel plate leveling device 2, a cutting and butt welding device 3, a steel plate pressing and guiding device 4, a rough forming rolling unit 5, a finish forming rolling unit 6, an automatic welding device 7, an internal and external weld bead leveling device 8, an on-line degreasing device 9, an on-line solution treatment device 10, a rough sizing unit 11, a finish sizing and straightening unit 12, a fixed-length shearing device 13, an end trimming and flattening device 14, an off-line quality inspection device 15, a ray detection device 16, a hydrostatic / airtight test device 17, a pickling and passivation device 18, an eddy current detector 19, a finished product inspection device 20 and a packaging and labeling device 21 are sequentially arranged according to the production process of large-diameter stainless steel straight-seam welded pipes;

[0043] The steel plate leveling device 2 includes a pinch roll device 2.1, a steel plate leveling machine 2.2 and a transmission device 2.3. The transmission device 2.3 is arranged on the inlet side of the pinch roll device 2.1, and the pinch roll device 2.1 is arranged on the inlet side of the steel plate leveling machine 2.2. The transmission device 2.3 feeds the uncoiled steel plate into the pinch roll device 2.1, and the pinch roll device 2.1 pinches and feeds the steel plate into the inlet side of the steel plate leveling machine 2.2;

[0044] The described end-cut butt welding device 3 includes a steel plate centering device Ⅰ 3.1, an end-cut butt welder 3.2, and a steel plate centering device Ⅱ 3.3. The steel plate centering device Ⅰ 3.1 and the steel plate centering device Ⅱ 3.3 are respectively arranged on the corresponding inlet side and outlet side of the end-cut butt welder 3.2;

[0045] The described rough forming rolling mill unit 5 includes at least five rough forming rolling mills arranged in sequence. Each rough forming rolling mill includes a frame 5.1.1, a screw down device 5.1.2, an upper roll 5.1.3, and a lower roll 5.1.4. The upper roll 5.1.3 and the lower roll 5.1.4 are installed on the frame 5.1.1. The screw down device 5.1.2 is installed on the frame 5.1.1 and is arranged above the upper roll 5.1.3. The screw down device 5.1.2 drives the upper roll 5.1.3 to move downward; In the rough forming rolling mill unit 5, the roll profiles of each rough forming rolling mill are gradually reduced in diameter (the upper and lower rolls of other rolling mills in the unit are not marked).

[0046] Furthermore, the described uncoiler 1 includes an uncoiler carriage 1.1 and an uncoiler 1.2. The uncoiler carriage 1.1 transports the steel coil to be rolled to the inlet position of the uncoiler 1.2.

[0047] Furthermore, the described steel plate leveling machine 2.2 includes an upper housing 2.2.1, upper leveling rolls 2.2.2, lower leveling rolls 2.2.3, and a lower housing 2.2.4. The upper leveling rolls 2.2.2 are installed in the upper housing 2.2.1, and the lower leveling rolls 2.2.3 are installed in the lower housing 2.2.4. The steel plate passes through the roll gap between the upper leveling rolls 2.2.2 and the lower leveling rolls 2.2.3.

[0048] Furthermore, the described finish forming rolling mill unit 6 includes a finish forming rolling mill Ⅰ 6.1, a finish forming rolling mill Ⅱ 6.2, and a finish forming rolling mill Ⅲ 6.3 arranged in sequence. The finish forming rolling mill Ⅰ 6.1 is composed of four vertical roll rolling mills.

[0049] Furthermore, the described rough sizing unit 11 includes a rough sizing machine Ⅰ 11.1, a rough sizing machine Ⅱ 11.2, a rough sizing machine Ⅲ 11.3, and a rough sizing machine Ⅳ 11.4 arranged in sequence.

[0050] Furthermore, the described finish sizing and straightening unit 12 includes a finish sizing and straightening machine Ⅰ 12.1 and a finish sizing and straightening machine Ⅱ 12.2 arranged in sequence. Both the finish sizing and straightening machine Ⅰ 12.1 and the finish sizing and straightening machine Ⅱ 12.2 are provided with four rolls arranged in a cross shape, and the included angle between the roll axes of the two finish sizing and straightening machines is arranged at 45°.

[0051] The usage process of this device is as follows:

[0052] S1. Uncoiling: The uncoiler carriage 1.1 transports the steel coil to be rolled to the inlet position of the uncoiler 1.2, and the steel coil performs an uncoiling operation on the uncoiler 1.2;

[0053] S2. Leveling: The uncoiler 1 feeds the steel plate after uncoiling in step S1 into the steel plate leveling device 2. The transmission device 2.3 feeds the uncoiled steel plate into the pinch roll device 2.1. The pinch roll device 2.1 pinches and feeds the steel plate to be leveled into the inlet side of the steel plate leveler 2.2 to level the steel plate before welding.

[0054] S3. Cutting the head and butt welding: The steel plate leveled in step S2 is fed into the cutting head and butt welding device 3. The steel plate centering device I 3.1 centers and clamps the head of the latter section of the steel plate. The steel plate centering device II 3.3 centers and clamps the tail of the former section of the steel plate. The cutting head and butt welder 3.2 cuts the head and tail ends of the front and rear steel plates neatly and welds them into one body to ensure the continuity of production.

[0055] S4. Pressing, guiding and edge planing of the steel plate: The steel plate pressing and guiding device 4 presses the edges of the steel plate welded into one body in step S3 to prevent the steel plate from bouncing up and down, and at the same time plays the role of centering, guiding and edge planing, making the edges of the steel plate neat and flat, and preparing for rough rolling and forming.

[0056] S5. Rough rolling and forming: At least five rough forming rolling mills are arranged in sequence along the direction of rough rolling and forming. The roll profiles of the rolls of each stand are configured according to the rough rolling and forming process, so that the stainless steel plate gradually bends from the edge to the middle part and rolls the steel plate into a tubular or cylindrical blank.

[0057] S6. Fine rolling and forming: The tubular or cylindrical blank after rough rolling and forming in step S5 is fed into the fine forming rolling mill I 6.1, the fine forming rolling mill II 6.2 and the fine forming rolling mill III 6.3 in sequence along the direction of fine rolling and forming to carry out fine rolling and forming on the tubular or cylindrical blank, so that the size of the tubular or cylindrical blank is close to the size of the finished pipe.

[0058] S7. Automatic welding: The tubular or cylindrical blank after fine rolling and forming in step S6 is fed into the automatic welding device 7. The automatic welding device 7 heats the metal in the welding area of the welded pipe to the molten state and realizes the welding of the welding area of the tubular or cylindrical blank through extrusion to obtain a stainless steel welded pipe.

[0059] S8. Leveling of internal and external weld beads: The stainless steel welded pipe after automatic welding in step S7 is fed into the internal and external weld bead leveling device 8 to level the internal weld of the stainless steel welded pipe, remove the excess height of the internal weld, and grind the external weld of the stainless steel welded pipe to eliminate the excess height of the external weld, so that the positions of the internal and external welds of the stainless steel welded pipe are flush with the base metal.

[0060] S9. On-line degreasing: The stainless steel welded pipe after leveling of internal and external weld beads in step S8 is fed into the on-line degreasing device 9 to remove the grease on the surface of the stainless steel welded pipe and make the surface of the steel pipe clean.

[0061] S10. Online solution treatment: Feed the stainless steel welded pipe after online degreasing in step S9 into the online solution treatment device 10 for online solution treatment to make the structure and composition of the stainless steel welded pipe uniform, eliminate internal stress, and restore the inherent wear resistance of the stainless steel;

[0062] S11. Rough sizing and forming: Feed the stainless steel welded pipe after online solution treatment in step S10 into the rough sizing machine I 11.1, rough sizing machine II 11.2, rough sizing machine III 11.3, and rough sizing machine IV 11.4 in sequence along the direction of rough sizing and forming to eliminate the ovality of the stainless steel welded pipe after automatic welding in step S7, and perform micro-calendering and stretching processing on the welded pipe;

[0063] S12. Fine sizing and forming and straightening: Feed the stainless steel welded pipe after rough sizing and forming in step S11 into the fine sizing and straightening machine I 12.1 and fine sizing and straightening machine II 12.2 in sequence along the direction of fine sizing and forming to eliminate the ovality of the stainless steel welded pipe for the second time, improve the dimensional accuracy of the stainless steel welded pipe, and straighten the stainless steel welded pipe in the length direction to eliminate internal stress and ensure the straightness of the welded pipe;

[0064] S13. Fixed-length shearing and offline quality inspection: Feed the stainless steel welded pipe straightened in step S12 into the fixed-length shearing device 13. The fixed-length shearing device 13 cuts the stainless steel welded pipe into the required fixed length, and then enters the offline quality inspection device 15 for comprehensive inspection to ensure the quality of the welded pipe. At the same time, at the offline quality inspection station, the end of the stainless steel welded pipe is leveled by the end trimming and flatting device 14 to remove burrs;

[0065] S14. Nondestructive flaw detection and sealing detection: First, feed the stainless steel welded pipe after offline quality inspection in step S13 into the ray detection device 16, irradiate the weld seam with rays to detect its internal defects and their types, shape dimensions, positions, and distributions; then, enter the hydrostatic / gas tightness test device 17 for hydrostatic / gas tightness test to inspect the sealing performance of the stainless steel welded pipe and check whether there are air leakage points;

[0066] S15. Pickling and passivation: Feed the stainless steel welded pipe after hydrostatic / gas tightness detection in step S14 into the pickling and passivation device 18 to remove the weld spots, mill scale, stains, and rust on the surface of the welded pipe, complete surface passivation, improve the corrosion resistance of the stainless steel welded pipe, and make the surface of the stainless steel welded pipe present a uniform silver-white color;

[0067] S16. Eddy current detection and finished product inspection: First, feed the stainless steel welded pipe after pickling and passivation in step S15 into the eddy current detector 19 to detect the defects on the surface and near the surface of the stainless steel welded pipe using the principle of electromagnetic induction; then, feed the stainless steel welded pipe after eddy current detection into the finished product inspection device 20 to perform appearance inspection, tightness inspection, and strength inspection on the stainless steel welded pipe;

[0068] Visual inspection is to inspect the defects on the surface of the weld seam and the dimensional deviations, which can be detected by tools such as standard templates, gauges and magnifying glasses. If defects appear on the surface, there may be defects inside the weld seam; tightness inspection is to detect defects such as cracks, pores, slag inclusions, lack of penetration and porosity, and methods such as kerosene test, water loading test and water flushing test are adopted; strength inspection can be carried out by two methods: hydrostatic test and pneumatic test;

[0069] S17. Packaging and labeling: The qualified stainless steel welded pipes detected in step S16 are sent to the packaging and labeling device 21 for packaging the products, and information labels of the products such as product name, product model, packaging outer dimensions, product gross weight, storage and transportation marks, manufacturer's name and address are pasted on the outer packaging of the goods. Finally, the finished stainless steel welded pipes leave the factory.

[0070] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for using a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes, characterized in that: According to the production process of large-diameter stainless steel straight-seam welded pipes, an uncoiler (1), a steel plate leveling device (2), a cut-end butt welding device (3), a steel plate pressing and guiding device (4), a rough forming rolling mill unit (5), a finish forming rolling mill unit (6), an automatic welding device (7), an internal and external weld leveling device (8), an online degreasing device (9), an online solution treatment device (10), a rough sizing unit (11), a finish sizing and straightening unit (12), a fixed-length shearing device (13), a trimming and flattening device (14), a offline quality inspection device (15), a ray detection device (16), a hydrostatic / gas tightness test device (17), a pickling and passivation device (18), an eddy current detector (19), a finished product inspection device (20) and a packaging and labeling device (21) are sequentially arranged; The steel plate leveling device (2) includes a pinch roll device (2.1), a steel plate leveling machine (2.2) and a transmission device (2.3). The transmission device (2.3) is arranged on the inlet side of the pinch roll device (2.1), and the pinch roll device (2.1) is arranged on the inlet side of the steel plate leveling machine (2.2). The transmission device (2.3) feeds the uncoiled steel plate into the pinch roll device (2.1), and the pinch roll device (2.1) pinches and feeds the steel plate into the inlet side of the steel plate leveling machine (2.2); The cut-end butt welding device (3) includes a steel plate centering device I (3.1), a cut-end butt welder (3.2) and a steel plate centering device II (3.3). The steel plate centering device I (3.1) and the steel plate centering device II (3.3) are respectively arranged on the corresponding inlet side and outlet side of the cut-end butt welder (3.2); The rough forming rolling mill unit (5) includes at least five sequentially arranged rough forming rolling mills. Each rough forming rolling mill includes a frame (5.1.1), a rolling reduction device (5.1.2), an upper roll (5.1.3) and a lower roll (5.1.4). The upper roll (5.1.3) and the lower roll (5.1.4) are installed on the frame (5.1.1), and the rolling reduction device (5.1.2) is installed on the frame (5.1.1) and arranged above the upper roll (5.1.3). The rolling reduction device (5.1.2) drives the upper roll (5.1.3) to move downward; in the rough forming rolling mill unit (5), the roll profiles of each rough forming rolling mill are gradually reduced in diameter; The using process of the continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes is as follows: S1. Uncoiling: The uncoiling trolley (1.1) transports the steel coil to be rolled to the inlet position of the uncoiler (1.2), and the steel coil is uncoiled on the uncoiler (1.2); S2. Leveling: The uncoiler (1) feeds the steel plate uncoiled in step S1 into the steel plate leveling device (2). The transmission device (2.3) feeds the uncoiled steel plate into the pinch roll device (2.1), and the pinch roll device (2.1) pinches and feeds the steel plate to be leveled into the inlet side of the steel plate leveling machine (2.2) to level the steel plate before welding; S3. Cut Head and Butt Welding: The steel plate leveled in step S2 is fed into the cut head and butt welding device (3). The steel plate centering device I (3.1) centers and clamps the head of the latter section of the steel plate, and the steel plate centering device II (3.3) centers and clamps the tail of the former section of the steel plate. The cut head and butt welder (3.2) cuts the head and tail ends of the front and rear steel plates neatly and welds them into one body, thus ensuring the continuity of production; S4. Steel Plate Pressing, Guiding and Edge Planing: The steel plate pressing and guiding device (4) presses the edges of the steel plate that are cut head and butt welded into one body in step S3 to prevent the steel plate from bouncing up and down, and at the same time plays the role of centering, guiding and edge planing, making the edges of the steel plate neat and flat, and preparing for rough rolling forming; S5. Rough Rolling Forming: At least five rough forming rolling mills are arranged in sequence along the direction of rough rolling forming. The roll profiles of the rolls of each stand are configured according to the rough rolling forming process, so that the stainless steel plate gradually bends from the edge to the middle part, and the steel plate is rolled into a tubular blank; S6. Finish Rolling Forming: The tubular blank after rough rolling forming in step S5 is successively fed into the finish forming rolling mill I (6.1), finish forming rolling mill II (6.2) and finish forming rolling mill III (6.3) along the finish rolling forming direction, and the tubular blank is subjected to finish rolling forming to make the size of the tubular blank close to the size of the finished pipe; S7. Automatic Welding: The tubular blank after finish rolling forming in step S6 is fed into the automatic welding device (7). The automatic welding device (7) heats the metal in the welding area of the welded pipe to the molten state, and realizes the welding of the welding area of the tubular blank through extrusion, and obtains a stainless steel welded pipe; S8. Inner and Outer Weld Seam Flattening: The stainless steel welded pipe after automatic welding in step S7 is fed into the inner and outer weld seam flattening device (8), flattens the inner weld seam of the stainless steel welded pipe, removes the excess height of the inner weld seam, and grinds the outer weld seam of the stainless steel welded pipe to eliminate the excess height of the outer weld seam, so that the positions of the inner and outer weld seams of the stainless steel welded pipe are flush with the base metal; S9. Online Degreasing: The stainless steel welded pipe after inner and outer weld seam flattening in step S8 is fed into the online degreasing device (9) to remove the grease on the surface of the stainless steel welded pipe and make the surface of the steel pipe clean; S10. Online Solution Treatment: The stainless steel welded pipe after online degreasing in step S9 is fed into the online solution treatment device (10) for online solution treatment, so that the structure and composition of the stainless steel welded pipe are uniform, the internal stress is eliminated, and the inherent wear resistance of the stainless steel is restored; S11. Rough Sizing Forming: The stainless steel welded pipe after online solution treatment in step S10 is successively fed into the rough sizing machine I (11.1), rough sizing machine II (11.2), rough sizing machine III (11.3) and rough sizing machine IV (11.4) along the rough sizing forming direction, eliminates the ovality of the stainless steel welded pipe after automatic welding in step S7, and performs micro-calendering and stretching processing on the welded pipe; S12. Finish Sizing Forming and Straightening: The stainless steel welded pipe after rough sizing forming in step S11 is successively fed into the finish sizing and straightening machine I (12.1) and finish sizing and straightening machine II (12.2) along the finish sizing forming direction, eliminates the ovality of the stainless steel welded pipe for the second time, improves the dimensional accuracy of the stainless steel welded pipe, and straightens the stainless steel welded pipe in the length direction to eliminate the internal stress and ensure the straightness of the welded pipe; S13. Cut-to-length shearing and offline quality inspection: The straightened stainless steel welded pipe after step S12 is sent to the cut-to-length shearing device (13). The cut-to-length shearing device (13) cuts the stainless steel welded pipe into the required fixed length, and then enters the offline quality inspection device (15) for comprehensive inspection to ensure the quality of the welded pipe. At the same time, at the offline quality inspection station, the end of the stainless steel welded pipe is flattened by the end trimming and flattening device (14) to remove burrs. S14. Nondestructive testing and leak tightness testing: First, the stainless steel welded pipe after offline quality inspection in step S13 is sent to the ray detection device (16). The weld seam is irradiated with rays to detect its internal defects, their types, shape dimensions, positions, and distributions. Then, it enters the hydrostatic / airtightness test device (17) for hydrostatic / airtightness test to check the leak tightness of the stainless steel welded pipe and check for any air leakage points. S15. Pickling and passivation: The stainless steel welded pipe after hydrostatic / airtightness detection in step S14 is sent to the pickling and passivation device (18) to remove the weld marks, mill scale, stains, and rust on the surface of the welded pipe, complete surface passivation, improve the corrosion resistance of the stainless steel welded pipe, and make the surface of the stainless steel welded pipe present a uniform silver-white color. S16. Eddy current testing and final product inspection: First, the stainless steel welded pipe after pickling and passivation in step S15 is sent to the eddy current detector (19). Using the principle of electromagnetic induction, defects on the surface and near the surface of the stainless steel welded pipe are detected. Then, the stainless steel welded pipe after eddy current testing is sent to the final product inspection device (20) for appearance inspection, tightness inspection, and strength inspection of the stainless steel welded pipe. S17. Packaging and labeling: The stainless steel welded pipe qualified after inspection in step S16 is sent to the packaging and labeling device (21). The product is packaged, and the product information label is pasted on the outer packaging of the goods. Finally, the finished product of the stainless steel welded pipe leaves the factory.

2. The method for using a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes according to claim 1, characterized in that: The uncoiling device (1) includes an uncoiling trolley (1.1) and an uncoiler (1.2). The uncoiling trolley (1.1) transports the steel coil to be rolled to the inlet position of the uncoiler (1.2).

3. The method for using a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes according to claim 1, characterized in that: The steel plate leveling machine (2.2) includes an upper machine base (2.2.1), upper leveling rolls (2.2.2), lower leveling rolls (2.2.3), and a lower machine base (2.2.4). The upper leveling rolls (2.2.2) are installed in the upper machine base ( 2.2.1), and the lower leveling rolls (2.2.3) are installed in the lower machine base (2.2.4). The steel plate passes through the roll gap between the upper leveling rolls (2.2.2) and the lower leveling rolls (2.2.3).

4. The method for using a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes according to claim 1, characterized in that: The precision forming rolling unit (6) includes a precision forming rolling mill I (6.1), a precision forming rolling mill II (6.2), and a precision forming rolling mill III (6.3) arranged in sequence. The precision forming rolling mill I (6.1) is composed of four vertical roll mills.

5. The usage method of a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes according to claim 1, characterized in that: the rough sizing unit (11) includes rough sizing machine I (11.1), rough sizing machine II (11.2), rough sizing machine III (11.3) and rough sizing machine IV (11.4) arranged in sequence.

6. The usage method of a continuous intelligent forming device for large-diameter stainless steel straight-seam welded pipes according to claim 1, characterized in that: the finish sizing and straightening unit (12) includes finish sizing and straightening machine I (12.1) and finish sizing and straightening machine II (12.2) arranged in sequence. Both finish sizing and straightening machine I (12.1) and finish sizing and straightening machine II (12.2) are provided with four rolls arranged in a cross shape, and the included angle between the axes of the rolls of the two finish sizing and straightening machines is arranged at 45°.

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