Steel Pipe Manufacturing System

Abstract

The present invention provides a steel pipe manufacturing system capable of acquiring, in a manufacturing process for, while continuously changing a form into a plate shape, a pipe shape, or the like, continuously applying coating and applying resin in each form, a thickness of a plate layer formed in each form and a thickness of the applied resin.　The steel pipe manufacturing system is provided with: a shaping device for continuously shaping, from a steel plate having a first surface and a second surface which faces the first surface, a pipe shaped body with the first surface as an inner surface and the second surface as an outer surface; and a shaping measurement unit for measuring at least one of a thickness of the steel plate and an outline of the pipe shaped body.

Description

[Technical field]

[0001] This relates to a system for managing the film thickness of plating layers, resin layers, etc. [Background technology]

[0002] There is known a method for measuring the thickness of a plating layer during the manufacturing process of steel sheets or the like (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2007-063647A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, the thickness of a steel plate or the like has been measured in one form, such as a plate, during the manufacturing process. However, it has not been possible to measure the dimensions while changing the form into various forms, such as a plate or a tube.

[0005] The present invention has been made in consideration of the above-mentioned points, and its object is to provide a steel pipe manufacturing system that can obtain dimensions for each shape, such as plate or tube, during a manufacturing process in which the shape is continuously changed. [Means for solving the problem]

[0006] The steel pipe manufacturing system according to the present invention has the following features: A forming device that continuously forms a tubular body from a plate-shaped steel sheet having a first surface and a second surface opposite to the first surface, the first surface being an inner surface and the second surface being an outer surface; At least one of a steel plate processing section that processes the steel plate and a tubular body processing section that processes the tubular body, The steel plate processing section 、 a steel sheet plating processing section that applies plating to the first surface of the steel sheet; A steel sheet thickness measuring unit that measures the thickness of the steel sheet before and after the first plating process by the steel sheet plating processing unit; a first plating thickness determination unit that determines whether or not the plating thickness of the first plating process is within a controllable range based on a difference between the sheet thickness before the first plating process and the sheet thickness after the first plating process, and determines a control parameter for the steel sheet plating processing unit when the plating thickness of the first plating process is within the controllable range; The steel plate Continuously While moving ,before The steel plate plating processing section and the steel plate thickness measuring section With Processing, Along with the movement of the steel plate At different positions on the steel plate, Implemented death, The processing of the first plating thickness determination unit is performed continuously, The tubular body processing section includes: The forming device forms the tubular body from the steel plate. Becoming After being molded ,before a tubular body plating processing section that performs plating on the second surface of the tubular body; a tubular body outer diameter measuring unit that measures the outer diameter of the tubular body before and after the second plating process by the tubular body plating processing unit; and a second plating thickness determination unit that determines whether or not the plating thickness of the second plating process is within a controllable range based on the difference between the outer diameter before the second plating process and the outer diameter after the second plating process, and determines a control parameter for the tubular body plating processing unit when the plating thickness of the second plating process is within the controllable range; The tubular body Continuously While moving ,before The tubular body plating processing section and the tubular body outer diameter measuring section With Processing, Along the movement of the tubular body At different positions, the tubular body is Then, the second plating thickness determination unit is continuously subjected to the process. , that is. Effect of the Invention

[0007] During the manufacturing process, which continuously changes the shape into a plate, a tube, etc., the dimensions of each shape can be obtained. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the configuration of a steel pipe manufacturing system 10 according to the present embodiment. [Diagram 2] 1 is a diagram showing a manufacturing apparatus for manufacturing a tubular body PB from a steel plate SS, and a process for manufacturing the tubular body PB using the manufacturing apparatus. [Diagram 3] FIG. 1 is a block diagram showing a configuration of a measurement device 100. [Figure 4] 13 is a perspective view showing a process of moving the steel sheet SS from the first pouring section 324 to the first wiping section 332. FIG. [Diagram 5] 10 is a partial cross-sectional view showing the positional relationship between a first wiping portion 332 and a steel plate SS. FIG. [Figure 6] 13 is a perspective view showing a process of moving the tubular body PB from the immersion section 426 to the second wiping section 432. FIG. [Figure 7] 13 is a partial cross-sectional view showing the positional relationship between a second wiping portion 432 and a tubular body PB. FIG. [Figure 8] 1 is a perspective view showing a state in which the thickness of a steel sheet SS is measured by a sheet thickness measuring device 110 before inner surface plating process or a sheet thickness measuring device 120 after inner surface plating process. FIG. [Figure 9] 1 is a perspective view showing the configurations of a pre-plating outer surface processing outer shape measuring device 130, a post-plating outer surface processing outer shape measuring device 140, a pre-coating outer shape measuring device 150, and a post-coating outer shape measuring device 160. FIG. [Figure 10] 2 is a block diagram showing an outline of the configuration of a control / determination unit 200 and a control device. FIG. [Figure 11] 13 is a flowchart showing a film thickness control process. [Figure 12] FIG. 2 is a perspective view showing an inner surface plating process corresponding position, an outer surface plating process corresponding position, and an outer surface coating process corresponding position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <<<<Outline of this embodiment>>>> Conventionally, when measuring the thickness or external shape of a plating or coating film, two pieces of equipment were required: one for manufacturing the steel pipes and one for measuring the manufactured steel pipes. Furthermore, each piece of equipment required personnel, space, money, and time.

[0010] In addition, various tests were required, such as a copper sulfate test to measure the uniformity of the plating on the manufactured steel pipes, and offline tests to measure the uniformity and adhesion of the coating. Since these tests are all destructive tests, it was necessary to create test specimens from the manufactured steel pipes, etc. The steel pipes from which the test specimens were taken could not be put on the market as products, and the tests inevitably reduced the yield.

[0011] Furthermore, the copper sulfate test, which is one of these destructive tests, requires 15 to 20 minutes to measure one test piece, and as a result, test data is only obtained intermittently (discontinuously) for products that are manufactured continuously, and does not continuously represent the entire product.

[0012] In addition, the parameters required for manufacturing, such as plating film thickness, coating film thickness, and external shape, must be changed according to various manufacturing conditions, and the values ​​of these parameters cannot be obtained in real time by destructive testing.

[0013] For this reason, since measurements are made using destructive testing, it is not possible to feed back the measurement results to the manufacturing equipment in real time. It is also not possible to generate and automatically output control signals based on the measurement results. Adding an input device to provide feedback to the manufacturing equipment inevitably increases costs.

[0014] <<First embodiment>> According to the first embodiment, A forming device (e.g., a forming device 342, etc.) that continuously forms a tubular body (e.g., a tubular body PB, etc.) from a plate-shaped steel plate (e.g., a steel plate SS, etc.) having a first surface (e.g., a first surface FF, etc. described later) and a second surface (e.g., a second surface SF, etc. described later) facing the first surface, with the first surface as an inner surface and the second surface as an outer surface; A steel pipe manufacturing system is provided that includes a forming measurement unit (e.g., a plate thickness measuring device 110 before inner plating process and a plate thickness measuring device 120 after inner plating process, or a shape measuring device 130 before outer plating process and a shape measuring device 140 after outer plating process, etc.) that measures at least one of the plate thickness of the steel plate and the outer shape of the tubular body (e.g., parameters that characterize the shape of the tubular body, such as diameter and roundness).

[0015] Non-destructive testing equipment, such as a device for measuring the thickness of steel plates and a device for measuring the outer shape of tubular bodies, can be incorporated into manufacturing facilities for continuous hot-dip metal-coated steel pipes, thereby reducing the equipment, space, manpower, time, and costs required for measurement.

[0016] The non-destructive testing equipment can be incorporated into the manufacturing facilities for continuous hot-dip metal-coated steel pipes, eliminating the need to prepare test pieces and improving yields. Furthermore, it also saves the equipment, space, manpower, and time required for destructive testing.

[0017] By incorporating a molding measurement unit into the manufacturing process, measurement results can be obtained on the spot without sampling. This configuration provides a manufacturing process monitoring system with improved speed and real-time performance.

[0018] <<Second embodiment>> The second embodiment is the same as the first embodiment, except that The forming measurement section includes a plate thickness measurement section that measures the plate thickness of the steel plate.

[0019] By incorporating a forming measurement unit into the manufacturing process, it is possible to measure the thickness of steel plates on the spot without sampling. This configuration makes it possible to provide a manufacturing process monitoring system with improved speed and real-time performance.

[0020] <<Third embodiment>> The third embodiment is the same as the first or second embodiment, The forming measuring section has an outer shape measuring section that measures the outer shape of the tubular body.

[0021] By incorporating a forming measurement unit into the manufacturing process, it is possible to measure the outer shape of the tubular body on the spot without sampling. With this configuration, it is possible to provide a manufacturing process monitoring system that is quicker and more real-time.

[0022] <<Fourth embodiment>> The fourth embodiment is the same as the first to third embodiments, a plating processing unit (e.g., an inner surface plating device 320 or an outer surface plating device 420) that applies plating to at least one of the first surface of the steel plate and the outer surface of the tubular body; A plating process measuring unit (e.g., a plate thickness measuring device 110 before inner surface plating process, a plate thickness measuring device 120 after inner surface plating process, a shape measuring device 130 before outer surface plating process, a shape measuring device 140 after outer surface plating process, etc.) that measures at least one of the plate thickness of the steel plate and the outer shape of the tubular body before and after the plating process by the plating processing unit; The plated film thickness determination unit (e.g., the control / determination unit 200) further includes a plated film thickness determination unit that determines the plated film thickness in the plating process from at least one of the difference between the plate thickness before the plating process and the plate thickness after the plating process, and the difference between the outer shape before the plating process and the outer shape after the plating process.

[0023] Measurement results of the uniformity of plating or coating, film thickness, and external shape can be obtained continuously and without delay. In addition, control signals are generated based on the obtained measurement results and sent to each manufacturing device to control the manufacturing device in real time, allowing the measurement results to be quickly reflected in the plating film or coating film, etc., making it possible to manufacture steel pipes with higher precision.

[0024] <<Fifth embodiment>> The fifth embodiment is the same as the fourth embodiment, The plating processing section has a first plating device (e.g., an inner surface plating device 320, etc.) that applies plating to the first surface of the steel sheet, The plating process measurement unit includes: A first thickness measuring device (e.g., a thickness measuring device 110 before an inner surface plating process) that measures the thickness of the steel sheet before the first plating process by the first plating device; A second thickness measuring device (e.g., a thickness measuring device 120 after an inner surface plating process) that measures the thickness of the steel sheet after the first plating process by the first plating device; The system has a first plating film thickness determination unit (e.g., control / determination unit 200) that determines the plating film thickness of the first plating process from the difference between the plate thickness before the first plating process and the plate thickness after the first plating process.

[0025] <<Sixth embodiment>> The sixth embodiment is the fourth embodiment or the fifth embodiment, The plating processing unit further includes a second plating device (e.g., an outer surface plating device 420, etc.) that applies plating to the outer surface of the tubular body, The plating process measurement unit includes: a first plate thickness measuring device (e.g., an outer shape measuring device 130 before outer surface plating process) that measures the outer shape of the tubular body before the second plating process by the second plating device; and a second plate thickness measuring device (e.g., a post-exterior plating process outer shape measuring device 140, etc.) that measures the outer shape of the tubular body after the second plating process by the second plating device, The apparatus further includes a second plating film thickness determination unit (e.g., control / determination unit 200) that determines the plating film thickness of the second plating process from the difference between the outer shape before the second plating process and the outer shape after the second plating process.

[0026] <<Seventh embodiment>> The seventh embodiment is the same as the fifth embodiment, a first film thickness adjusting device (e.g., a first wiping unit 332, etc.) that adjusts the plating film thickness in the first plating process; The apparatus further includes a first film thickness control device (for example, control and determination unit 200) that controls the first film thickness adjustment device based on a determination result from the first plating film thickness determination unit.

[0027] <<Eighth embodiment>> The eighth embodiment is the same as the sixth embodiment, A second film thickness adjustment device (e.g., a second wiping unit 432, etc.) that adjusts the plating film thickness in the second plating process; The apparatus further includes a second film thickness control device (for example, control and determination unit 200) that controls the second film thickness adjustment device based on the determination result of the second plating film thickness determination unit.

[0028] <<Ninth embodiment>> The ninth embodiment is the same as the first embodiment to the eighth embodiment, A coating device (e.g., a topcoat device 520) for forming a coating film on the outer surface; a coating outer shape measuring unit (e.g., a pre-coating outer shape measuring device 150 and a post-coating outer shape measuring device 160, etc.) for measuring the outer shape of the tubular body before and after the coating process by the coating device; The apparatus further includes a coating thickness determination unit (such as the control and determination unit 200) that determines the coating thickness from the difference between the outer shape before and after coating.

[0029] <<Tenth embodiment>> The tenth embodiment is the same as the ninth embodiment, A coating thickness adjusting device (e.g., a third wiping unit 532, etc.) for adjusting the thickness of the coating film in the coating process; The coating film thickness control device (eg, control / determination unit 200) controls the coating film thickness adjustment device based on the determination result of the coating film thickness determination unit.

[0030] <<Eleventh embodiment>> According to an eleventh embodiment, A forming device that continuously forms a tubular body from a plate-shaped steel plate having a first surface and a second surface opposite to the first surface, the first surface being an inner surface and the second surface being an outer surface; a plating processing unit that applies plating to at least one of the first surface of the steel plate and the outer surface of the tubular body; a plating process measuring unit that measures at least one of a thickness of the steel sheet and an outer diameter of the tubular body before and after a plating process by the plating processing unit; The plating process includes a plating film thickness determination unit that determines the plating film thickness of the plating process from at least one of the difference between the plate thickness before the plating process and the plate thickness after the plating process, and the difference between the outer shape before the plating process and the outer shape after the plating process.

[0031] <<Twelfth embodiment>> The twelfth embodiment is the same as the eleventh embodiment, The plating processing section has a first plating device that applies plating to the first surface of the steel sheet, The plating process measurement unit includes: a first thickness measuring device that measures the thickness of the steel sheet before the first plating step by the first plating device; A second thickness measuring device that measures the thickness of the steel sheet after the first plating process by the first plating device; and a first plating thickness determination unit that determines the plating thickness of the first plating step from the difference between the plate thickness before the first plating step and the plate thickness after the first plating step.

[0032] <<Thirteenth embodiment>> The thirteenth embodiment is the eleventh embodiment or the twelfth embodiment, The plating processing section further includes a second plating device that applies plating to the outer surface of the tubular body, The plating process measurement unit includes: a first thickness measuring device that measures an outer shape of the tubular body before the second plating step by the second plating device; and a second thickness measuring device that measures the outer shape of the tubular body after the second plating step by the second plating device, The apparatus further includes a second plating thickness determination unit that determines the plating thickness of the second plating process from the difference between the outer shape before the second plating process and the outer shape after the second plating process.

[0033] <<Fourteenth embodiment>> The fourteenth embodiment is the same as the twelfth embodiment, a first film thickness adjusting device for adjusting a plating film thickness in the first plating step; The apparatus further includes a first film thickness control device that controls the first film thickness adjustment device based on a determination result from the first plating film thickness determination section.

[0034] <<Fifteenth embodiment>> The fifteenth embodiment is the same as the thirteenth embodiment, a second film thickness adjusting device for adjusting a plating film thickness in the second plating step; The plating apparatus further includes a second film thickness control device that controls the second film thickness adjustment device based on a determination result from the second plating film thickness determination section.

[0035] <<Sixteenth embodiment>> The 16th embodiment is the same as the 11th embodiment to the 15th embodiment, A coating device for forming a coating film on the outer surface; a coating outer shape measuring unit for measuring the outer shape of the tubular body before and after the coating process by the coating device; The apparatus further includes a coating thickness determination unit that determines the coating thickness from the difference between the outer shape before and after coating.

[0036] <<Seventeenth embodiment>> The seventeenth embodiment is the same as the sixteenth embodiment, a coating thickness adjusting device for adjusting the thickness of the coating film in the coating process; The coating film thickness control device further includes a coating film thickness control device that controls the coating film thickness adjustment device based on a result of the determination by the coating film thickness determination section.

[0037] <<Eighteenth embodiment>> According to an eighteenth embodiment, A forming device that continuously forms a tubular body from a plate-shaped steel plate having a first surface and a second surface opposite to the first surface, the first surface being an inner surface and the second surface being an outer surface; A coating device for forming a coating film on the outer surface; a coating outer shape measuring unit for measuring the outer shape of the tubular body before and after the coating process by the coating device; and a coating thickness determination unit that determines the coating thickness from the difference between the outer shape before and after coating.

[0038] <<19th embodiment>> The 19th embodiment is the same as the 18th embodiment, a coating thickness adjusting device for adjusting the thickness of the coating film in the coating process; The coating film thickness control device further includes a coating film thickness control device that controls the coating film thickness adjustment device based on a result of the determination by the coating film thickness determination section.

[0039] <<20th embodiment>> The twentieth embodiment is In the first plating step by the first plating device, the steel sheet is transported at a single transport speed; In a forming process by a forming device, the steel sheet and the tubular body are transported at the same transport speed as the first transport speed while being kept integral with the steel sheet passing through the first plating device; The apparatus further includes a conveying device that conveys the tubular body at the same conveying speed as the first conveying speed while maintaining the tubular body integral with the steel plate and the tubular body passing through the forming device in the second plating process by the second plating device.

[0040] <<21st embodiment>> The twenty-first embodiment is The plate thickness measuring unit measures the plate thickness of the steel plate while the conveying device conveys the steel plate at the same conveying speed as the first conveying speed.

[0041] <<22nd embodiment>> The twenty-second embodiment is The outer shape measuring unit measures the outer shape of the tubular body while the transport device transports the tubular body at the same transport speed as the first transport speed.

[0042] <<23rd embodiment>> The twenty-third embodiment is The tubular body is maintained as a single unit and is transported by the transport device at the same transport speed as the first transport speed, while the coating device coats the outer surface of the tubular body.

[0043] <<24th embodiment>> The twenty-fourth embodiment is The coating outer shape measuring unit measures the outer shape of the tubular body while the conveying device conveys the tubular body at the same conveying speed as the first conveying speed.

[0044] <<<<<Details of this embodiment>>>> Hereinafter, an embodiment will be described with reference to the drawings.

[0045] Fig. 1 is a schematic diagram showing the configuration of a steel pipe manufacturing system 10. The steel pipe manufacturing system 10 has a measuring device 100, a control and judgment unit 200, and a manufacturing device 300. The measuring device 100 has a device for measuring the plate thickness of the steel plate SS and a device for measuring the outer shape of the tubular body PB (see Fig. 3 described later). The control and judgment unit 200 controls the manufacturing device 300 based on the plate thickness and outer shape measured by the measuring device 100. The manufacturing device 300 is a device for manufacturing the tubular body PB from the steel plate SS (see Figs. 2 and 10 described later).

[0046] The measuring device 100, the control and determination unit 200, and the manufacturing device 300 will be described in detail below.

[0047] <<<Outline of manufacturing process>>> FIG. 2 is a diagram showing a manufacturing apparatus 300 for manufacturing a tubular body PB from a steel plate SS, and a process for manufacturing the tubular body PB using the manufacturing apparatus 300. As shown in FIG.

[0048] By processing from upstream to downstream in the manufacturing process, a steel sheet SS (steel strip) having a long strip shape that is pre-wound on a coil (not shown) can be sent out and continuously formed into a tubular shape to manufacture the tubular body PB. That is, the manufacturing process is a process for transforming the flat steel sheet SS into the tubular body PB.

[0049] When the steel sheet SS is discharged from the coil, it is formed into a flat shape. The steel sheet SS has a flat first surface FF and a flat second surface SF facing the first surface FF. When formed into a tubular body PB, the first surface FF becomes the inner surface IF of the tubular body PB, and the second surface SF becomes the outer surface OF of the tubular body PB. Hereinafter, for convenience of explanation, even when the steel sheet SS is in the form of a steel sheet SS, the first surface FF may be referred to as the inner surface IF.

[0050] In the following, the direction along the length of the steel plate SS or tubular body PB having a long shape is referred to as the longitudinal direction LD. The direction along the width of the steel plate SS or the radius (diameter) of the tubular body PB is referred to as the width direction WD. The width direction WD is a direction perpendicular to the longitudinal direction LD. The direction parallel to the normal direction of the first surface FF of the steel plate SS is referred to as the perspective direction PD. The perspective direction PD is also a direction perpendicular to the longitudinal direction LD.

[0051] As shown in FIG. 2, the manufacturing process includes a pre-treatment device 310, a first cleaning device 312, a first heating device 314, an inner surface plating device 320, a first film thickness adjustment device 330, a first cooling device 340, a forming device 342, a welding device 350, a bead cutting device 352, a second cleaning device 412, a second heating device 414, an outer surface plating device 420, a second film thickness adjustment device 430, a second cooling device 440, a sizing device 442, a top coat device 520, a third film thickness adjustment device 530, a drying device 550, and a cutting device 560.

[0052] <<Pretreatment device 310>> The pretreatment device 310 performs surface treatment on both the first face FF and the second face SF of the steel sheet SS to remove the oxide film layer.

[0053] <<First Cleaning Device 312>> The first cleaning device 312 cleans the first surface FF of the steel sheet SS with a liquid such as acid or water. The liquid may be a flux liquid for cleaning and oxidation prevention.

[0054] <<First heating device 314>> The first heating device 314 has a heater (not shown) and dries the first side FF of the steel sheet SS and heats the steel sheet SS. The first heating temperature of the first heating device 314 affects the quality of the coating layer on the first side FF, etc. The first heating temperature is a control parameter for the heat treatment.

[0055] <<Inner surface plating device 320>> The inner surface plating device 320 pours a desired molten metal onto the first surface FF of the steel sheet SS. The first surface FF of the steel sheet SS is plated by pouring the molten metal onto the first surface FF. The plating device has a first molten metal pump 322 and a first pouring unit 324 (see FIG. 4). The first molten metal pump 322 supplies molten metal to the first pouring unit 324. The first pouring unit 324 pours the molten metal supplied from the first molten metal pump 322 onto the first surface FF of the steel sheet SS. The temperature of the molten metal affects the plating film thickness on the first surface FF, etc. The temperature of the molten metal is a control parameter of the inner surface plating device 320. In addition, when the first pouring unit 324 can be moved along the longitudinal direction LD, the position of the first pouring unit 324 can also be a control parameter of the inner surface plating device 320. For example, by providing a drive device (not shown) made up of a motor, a solenoid, or the like, similar to first movable part 334 described below, the position of first pouring part 324 in the longitudinal direction LD can be adjusted.

[0056] <<First Film Thickness Adjusting Device 330>> The first film thickness adjusting device 330 blows gas onto the first surface FF of the steel sheet SS after plating. The first film thickness adjusting device 330 has a first wiping part 332 and a first movable part 334.

[0057] <First wiping section 332> The first wiping unit 332 removes excess molten metal from the molten metal poured onto the first face FF by the first pouring unit 324. The first wiping unit 332 blows gas such as an inert gas or an air wiper onto the first face FF of the steel sheet SS (arrows AR in Figs. 4 and 5 ) to remove excess molten metal.

[0058] <First movable part 334> The first movable portion 334 has three driving devices 336a, 336b, and 336c each including a motor, a solenoid, or the like (not shown). The driving devices 336a, 336b, and 336c are drivably connected to the first wiping portion 332.

[0059] The driving device 336a drives the first wiping unit 332 so as to be reciprocable in the longitudinal direction LD. By driving the driving device 336a, the distance from the first pouring unit 324 to the first wiping unit 332 can be adjusted.

[0060] The driving device 336b drives the first wiping portion 332 so as to be movable in the far-near direction PD. By driving the driving device 336b, the distance from the first wiping portion 332 to the steel sheet SS can be adjusted (see FIG. 5).

[0061] The driving device 336c drives the first wiping unit 332 to rotate clockwise or counterclockwise relative to the steel plate SS. The inclination (angle) of the wiping unit with respect to the first surface FF of the steel plate SS can be adjusted (see FIG. 5).

[0062] The inner surface plating film thickness and its distribution are determined by the distance from the first pouring part 324 to the first wiping part 332, the distance from the first wiping part 332 to the steel sheet SS, and the inclination of the wiping part with respect to the first surface FF of the steel sheet SS. The distance from the first pouring part 324 to the first wiping part 332, the distance from the first wiping part 332 to the steel sheet SS, and the inclination of the wiping part with respect to the first surface FF of the steel sheet SS are control parameters of the inner surface plating process.

[0063] In addition, the flow rate and flow rate distribution of the gas discharged from the first wiping unit 332 and wiped onto the first surface FF of the steel sheet SS also affect the thickness of the inner surface plating. For example, the nozzle of the first wiping unit 332 can be provided with a mechanism (not shown) that can adjust the flow rate and flow rate distribution of the gas discharged from the first wiping unit 332. The flow rate and flow rate distribution of the gas discharged from the first wiping unit 332 are control parameters for the inner surface plating process.

[0064] The first wiping part 332 may be fixed at a constant position and angle. By fixing the position and angle, the first wiping part 332 is less susceptible to the effects of vibrations and the like, and the position of the first wiping part 332 can be stabilized, allowing excess molten metal to be removed accurately.

[0065] <<First cooling device 340>> The first cooling device 340 cools the steel sheet SS after hot-dip galvanization.

[0066] <<Forming device 342>> The forming device 342 has a roll forming device (not shown) and the like. The forming device 342 continuously deforms the steel plate SS into a tubular shape to form the tubular body PB. This process allows the steel plate SS to be transformed into a tubular shape. The forming by the forming device 342 can be appropriately selected from cold forming, warm forming, hot forming, and the like, depending on the material of the steel plate SS and the material of the plating. In the steel pipe manufacturing system 10, the steel plate SS is continuously formed into the tubular body PB while maintaining the integral state. In other words, the steel plate SS can be continuously processed into the tubular body PB without making the conveying speed of the steel plate SS different from the conveying speed of the tubular body PB.

[0067] <<Welding device 350>> The welding device 350 welds two ends of the steel plate SS facing each other along the longitudinal direction LD to form a tubular body PB without any gaps.

[0068] <<Bead cutting device 352>> The bead cutting device 352 has a blade (not shown) and continuously cuts the weld bead portion formed by the welding process with the blade. By the cutting process, the outer surface OF of the tubular body PB can be formed smoothly.

[0069] <<Second Cleaning Device 412>> The second cleaning device 412 cleans the outer surface OF of the tubular body PB with a liquid such as acid or water. The liquid may be a flux liquid for cleaning and oxidation prevention.

[0070] <<Second heating device 414>> The second heating device 414 has a heater (not shown) and dries the outer surface OF of the tubular body PB and heats the tubular body PB. The second heating temperature of the second heating device 414 affects the quality of the plating layer on the inner surface IF. The second heating temperature is a control parameter for the heat treatment.

[0071] <<External plating device 420>> The external plating device 420 continuously performs hot-dip metal plating on the outer surface OF of the tubular body PB to form a hot-dip metal plated steel pipe. The external plating device 420 has a second molten metal pump 422 and an immersion section 426 (see FIG. 6). The second molten metal pump 422 supplies molten metal to the immersion section 426. The immersion section 426 stores the supplied molten metal and passes the tubular body PB through the immersion section 426 to perform hot-dip metal plating on the outer surface OF. The temperature of the molten metal affects the plating film thickness on the outer surface OF, etc. The temperature of the molten metal is a control parameter of the external plating device 420.

[0072] The external plating apparatus 420 may be provided with a plurality of immersion sections 426. The immersion time and other factors can be adjusted depending on the number of immersion sections 426 operated. The number of immersion sections 426 operated may be changed depending on the type of molten metal, etc. In this way, the number of immersion sections 426 operated may also be a control parameter for the external plating apparatus 420.

[0073] Furthermore, among the multiple immersion parts 426 operated, the position of the immersion part 426 closest to the second wiping part 432 described below can also be a control parameter of the outer surface plating device 420. By changing the number of immersion parts 426 operated, it is possible to adjust the distance between the immersion part 426 closest to the second wiping part 432 and the second wiping part 432. Furthermore, by providing the immersion part 426 with a driving device (not shown) consisting of a motor, a solenoid, or the like, similar to the first movable part 334, it is also possible to adjust the position of the immersion part 426 in the longitudinal direction LD.

[0074] <<Second Film Thickness Adjusting Device 430>> The second film thickness adjusting device 430 blows gas onto the outer surface OF of the tubular body PB after plating. The second film thickness adjusting device 430 has a second wiping part 432 and a second movable part 434 (see FIG. 6).

[0075] <Second wiping section 432> The second wiping unit 432 removes excess molten metal adhering to the outer surface OF of the tubular body PB in the immersion unit 426. The second wiping unit 432 blows a gas such as an inert gas or an air wiper onto the outer surface OF of the tubular body PB to remove excess molten metal. The second wiping unit 432 has a through hole 438. The tubular body PB can pass through the through hole 438 of the second wiping unit 432. When the tubular body PB passes through the through hole 438, gas (arrow AR in FIG. 7) is wiped onto the tubular body PB to remove excess molten metal.

[0076] <Second movable part 434> The second movable portion 434 has three driving devices 436a, 436b, and 436c each including a motor, a solenoid, or the like (not shown). The driving devices 436a, 436b, and 436c are drivably connected to the second wiping portion 432.

[0077] Driving device 436a drives second wiping unit 432 so as to be reciprocatingly movable in longitudinal direction LD. By driving driving device 436a, the distance from immersion unit 426 to second wiping unit 432 can be adjusted.

[0078] The driving device 436b drives the second wiping portion 432 so as to be reciprocating in the width direction WD. The driving device 436c drives the second wiping portion 432 so as to be reciprocating in the far-near direction PD. By driving the driving device 436b, the distance in the width direction WD from the second wiping portion 432 to the outer periphery of the tubular body PB can be adjusted. By driving the driving device 436c, the distance in the far-near direction PD from the second wiping portion 432 to the outer periphery of the tubular body PB can be adjusted (see FIG. 7). By driving the driving devices 436b and 436c, the center PO of the tubular body PB can be made eccentric from the center WO of the through hole 438 of the second wiping portion 432.

[0079] The outer plating thickness and the distribution of the outer plating thickness are determined by the distance from the immersed portion 426 to the second wiping portion 432, the distance in the width direction WD from the second wiping portion 432 to the outer periphery of the tubular body PB, and the distance in the far direction PD from the second wiping portion 432 to the outer periphery of the tubular body PB. The distance from the immersed portion 426 to the second wiping portion 432, the distance in the width direction WD from the second wiping portion 432 to the outer periphery of the tubular body PB, and the distance in the far direction PD from the second wiping portion 432 to the outer periphery of the tubular body PB are control parameters of the outer plating process.

[0080] In addition, the flow rate and flow rate distribution of the gas discharged from the second wiping unit 432 and wiped onto the outer surface OF of the tubular body PB also affect the outer surface plating film thickness. For example, a mechanism (not shown) capable of adjusting the flow rate and flow rate distribution of the gas discharged from the second wiping unit 432 can be provided on the nozzle of the second wiping unit 432. The flow rate and flow rate distribution of the gas discharged from the second wiping unit 432 are control parameters for the outer surface plating process.

[0081] The second wiping part 432 may be fixed at a fixed position. By fixing the position, it is possible to make the second wiping part 432 less susceptible to the effects of vibrations and the like, and to stabilize the position of the second wiping part 432, thereby enabling the excess molten metal to be removed accurately.

[0082] <<Second cooling device 440>> The second cooling device 440 cools the tubular body PB which has been heated by the outer surface plating process.

[0083] <<Sizing device 442>> The sizing device 442 is a process in which the tubular body PB after the outer surface plating process is cold-rolled using a forming device (not shown) having multiple rollers to adjust the outer shape and make the cross-sectional shape closer to a perfect circle, thereby forming it into the standard dimensions.

[0084] <<Topcoat device 520>> The topcoat device 520 is a process for applying resin to the outer surface OF of the tubular body PB. By applying the resin, the plating applied to the outer surface OF of the tubular body PB can be protected.

[0085] Furthermore, in the case where the top coat device 520 can be moved along the longitudinal direction LD, the position of the top coat device 520 can also be a control parameter of the top coat device 520. For example, by providing a driving device (not shown) consisting of a motor, a solenoid, or the like, similar to the above-mentioned first movable part 334, the position of the top coat device 520 in the longitudinal direction LD can be adjusted.

[0086] <<Third air blow device 530>> The third air blowing device 530 blows gas onto the outer surface OF of the tubular body PB after the resin has been applied. The third air blowing device 530 has a third wiping part 532 and a third movable part 534.

[0087] 6 and 7, for the sake of convenience, the top coat device 520, the third wiping unit 532, and the third movable unit 534 are indicated with parentheses to indicate their positional relationship. The immersion unit 426 of the outer surface plating device 420 corresponds to the top coat device 520, the third wiping unit 532 corresponds to the second wiping unit 432, and the third movable unit 534 corresponds to the second movable unit 434.

[0088] <Third wiping section 532> The third wiping unit 532 has the same function as the second wiping unit 432. The third wiping unit 532 removes excess resin from the resin applied by the top coat device 520. The third wiping unit 532 blows gas such as an inert gas or an air wiper onto the outer surface OF of the tubular body PB to remove excess resin. The third wiping unit 532 has an annular shape and has a through hole 538. The tubular body PB can pass through the through hole 538 of the third wiping unit 532. When the tubular body PB passes through the through hole 538, the gas is wiped onto the tubular body PB to remove excess resin.

[0089] <Third movable part 534> The third movable portion 534 has three driving devices 536a, 536b, and 536c each including a motor, a solenoid, or the like (not shown). The driving devices 536a, 536b, and 536c are drivably connected to the third wiping portion 532.

[0090] The driving device 536a drives the third wiping unit 532 so as to be reciprocatingly movable in the longitudinal direction LD. By driving the driving device 536a, the distance from the top coat device 520 to the third wiping unit 532 can be adjusted.

[0091] The driving device 536b drives the third wiping portion 532 so as to be reciprocating in the width direction WD. The driving device 536c drives the third wiping portion 532 so as to be reciprocating in the far-near direction PD. By driving the driving device 536b, the distance in the width direction WD from the third wiping portion 532 to the outer periphery of the tubular body PB can be adjusted. By driving the driving device 536c, the distance in the far-near direction PD from the third wiping portion 532 to the outer periphery of the tubular body PB can be adjusted (see FIG. 7). By driving the driving devices 536b and 536c, the center PO of the tubular body PB can be offset from the center WO of the through hole 538 of the third wiping portion 532.

[0092] The thickness and distribution of the resin layer thickness are determined by the distance from the top coat device 520 to the third wiping unit 532, the distance in the width direction WD from the third wiping unit 532 to the outer periphery of the tubular body PB, and the distance in the far direction PD from the third wiping unit 532 to the outer periphery of the tubular body PB. The distance from the top coat device 520 to the third wiping unit 532, the distance in the width direction WD from the third wiping unit 532 to the outer periphery of the tubular body PB, and the distance in the far direction PD from the third wiping unit 532 to the outer periphery of the tubular body PB are control parameters for the resin thickness.

[0093] In addition, the flow rate and flow rate distribution of the gas discharged from the third wiping unit 532 and wiped onto the outer surface OF of the tubular body PB also affect the film thickness of the resin. For example, a mechanism (not shown) capable of adjusting the flow rate and flow rate distribution of the gas discharged from the third wiping unit 532 can be provided on the nozzle of the third wiping unit 532. The flow rate and flow rate distribution of the gas discharged from the third wiping unit 532 are control parameters for the film thickness of the resin.

[0094] The third wiping part 532 may be fixed at a fixed position. By fixing the position, it is possible to make the third wiping part 532 less susceptible to the effects of vibrations and the like, and to stabilize the position of the third wiping part 532, thereby enabling the excess resin to be removed accurately.

[0095] <<Drying equipment 550>> The drying device 550 dries the resin applied to the outer surface OF of the tubular body PB.

[0096] <<Cutting device 560>> The cutting device 560 is a device for cutting the tubular body PB to a predetermined length.

[0097] <<Transportation device 600>> As described above, in the steel pipe manufacturing system 10, the steel plate SS is continuously formed into the tubular body PB while maintaining the integral state. That is, the conveying device 600 conveys the steel plate SS and the tubular body PB at a constant conveying speed TV. The steel plate SS and the tubular body PB are continuously conveyed by the conveying device 600 from the pre-treatment device 310 to the drying device 550 without stopping while maintaining the integral state. In other words, in all the steps of the process in which the steel plate SS changes its shape into the tubular body PB, the steel plate SS and the tubular body PB are conveyed at a constant speed (the conveying speed of the steel plate SS and the conveying speed of the tubular body PB are equal (conveying speed TV)). The conveying speed is also a control parameter that commonly controls the plating time of the inner surface plating, the plating time of the outer surface plating, the coating time of the resin, etc.

[0098] <<<Measuring Apparatus 100>>> 3 is a block diagram showing the configuration of the measuring device 100. The measuring device 100 has a sheet thickness measuring device 110 before inner surface plating process, a sheet thickness measuring device 120 after inner surface plating process, a contour measuring device 130 before outer surface plating process, a contour measuring device 140 after outer surface plating process, a contour measuring device 150 before coating process, and a contour measuring device 160 after coating process.

[0099] <Pre-inner-plate-plating-processing sheet-thickness measuring device 110 and post-inner-plate-plating-processing sheet-thickness measuring device 120> The sheet thickness measuring device 110 before the inner surface plating process is a device for measuring the sheet thickness of the steel sheet SS before the inner surface plating process. Specifically, the sheet thickness of the steel sheet SS can be measured between the cleaning process by the first cleaning device 312 and the heating process by the first heating device 314 ((1-1) shown in FIG. 2). In addition, the sheet thickness of the steel sheet SS can be measured between the heating process by the first heating device 314 and the plating process by the inner surface plating device 320 ((1-2) shown in FIG. 2).

[0100] The sheet thickness measuring device 120 after inner surface plating is a device for measuring the sheet thickness of the steel sheet SS after the inner surface plating. Specifically, the sheet thickness of the steel sheet SS can be measured between the gas blowing process by the first air blowing device 330 and the cooling process by the first cooling device 340 ((2-1) shown in FIG. 2). In addition, the sheet thickness of the steel sheet SS can be measured between the cooling process by the first cooling device 340 and the roll forming process by the forming device 342 ((2-2) shown in FIG. 2).

[0101] The sheet thickness measuring device 110 before inner surface plating process and the sheet thickness measuring device 120 after inner surface plating process irradiate the steel sheet SS with laser light and receive the light reflected from the steel sheet SS, thereby measuring the displacement of the steel sheet SS.

[0102] The sheet thickness measuring device 110 before inner surface plating process and the sheet thickness measuring device 120 after inner surface plating process have sensor heads 112a and 112b (see FIG. 8) and a controller (not shown). The sensor heads 112a and 112b are connected to the controller. The sensor head 112a detects the displacement of a first surface FF of the steel sheet SS. The sensor head 112b detects the displacement of a second surface SF of the steel sheet SS. The sensor heads 112a and 112b are sensors that optically detect the displacement. The sensor heads 112a and 112b output detection signals indicative of the detected displacement. The detection signals are supplied to the controller.

[0103] FIG. 8 is a perspective view showing a state in which the thickness of a steel sheet SS is measured by the sheet thickness measuring device 110 before inner surface plating process or the sheet thickness measuring device 120 after inner surface plating process.

[0104] The sensor head 112a irradiates a laser beam onto a first surface FF of the steel plate SS, receives the light reflected from the first surface FF, and measures the displacement of the first surface FF of the steel plate SS. The sensor head 112b irradiates a laser beam onto a second surface SF of the steel plate SS, receives the light reflected from the second surface SF, and measures the displacement of the second surface SF of the steel plate SS. A signal indicating the displacement of the first surface FF of the steel plate SS and a signal indicating the displacement of the second surface SF of the steel plate SS are supplied to the control and determination unit 200 via a controller (not shown).

[0105] As shown in FIG. 8, the sensor heads 112a and 112b are arranged concentrically. The control and determination unit 200 can obtain the thickness of the steel plate SS from the displacement of the first surface FF detected by the sensor head 112a and the displacement of the second surface SF detected by the sensor head 112b. The sensor heads 112a and 112b have a driving device (not shown). The sensor heads 112a and 112b can move along the width direction WD while maintaining the concentric state by the driving device. The sensor heads 112a and 112b can measure the thickness of the steel plate SS at any position along the width direction WD. In this embodiment, the sensor heads 112a and 112b are constantly moved back and forth by the driving device to measure the thickness of the steel plate SS.

[0106] The control and judgment unit 200 obtains the thickness of the steel sheet SS before the inner surface plating process using the pre-inner surface plating process thickness measuring device 110. Similarly, the control and judgment unit 200 obtains the thickness of the steel sheet SS after the inner surface plating process using the post-inner surface plating process thickness measuring device 120. The control and judgment unit 200 can obtain the thickness of the plating formed by the inner surface plating process from the thickness of the steel sheet SS before the inner surface plating process and the thickness of the steel sheet SS after the inner surface plating process.

[0107] <Apparatus 130 for measuring outer shape before outer plating process and apparatus 140 for measuring outer shape after outer plating process> The pre-exterior plating process outer shape measuring device 130 is a device for measuring the outer shape of the tubular body PB (e.g., parameters that characterize the shape of the tubular body PB, such as diameter and roundness) before the outer surface plating process. Specifically, the outer shape of the tubular body PB can be measured between the cleaning process by the second cleaning device 412 and the heating process by the second heating device 414 ((3-1) shown in FIG. 2). In addition, the outer shape of the tubular body PB can be measured between the heating process by the second heating device 414 and the plating process by the outer surface plating device 420 ((3-2) shown in FIG. 2).

[0108] The post-external plating process outer shape measuring device 140 is a device for measuring the outer shape of the tubular body PB after the external plating process (for example, parameters that characterize the shape of the tubular body PB, such as diameter and roundness). Specifically, the outer shape of the tubular body PB can be measured between the gas blowing process by the second air blowing device 430 and the cooling process by the second cooling device 440 ((4-1) shown in FIG. 2). In addition, the outer shape of the tubular body PB can be measured between the cooling process by the second cooling device 440 and the molding process by the sizing device 442 ((4-2) shown in FIG. 2).

[0109] The pre-plating outer shape measuring device 130 and the post-plating outer shape measuring device 140 measure the outer shape of the tubular body PB by irradiating laser light onto the tubular body PB and receiving the light reflected from the tubular body PB.

[0110] 9 is a perspective view showing the configurations of the pre-plating outer surface processing outer shape measuring device 130, the post-plating outer surface processing outer shape measuring device 140, the pre-coating outer surface processing outer shape measuring device 150, and the post-coating outer surface processing outer shape measuring device 160. Note that the pre-coating outer surface processing outer shape measuring device 150 and the post-coating outer surface processing outer shape measuring device 160 have the same configurations as the pre-plating outer surface processing outer shape measuring device 130 and the post-plating outer surface processing outer shape measuring device 140.

[0111] As shown in Fig. 9, the pre-exterior plating process outer shape measuring device 130 is installed on the transport path of the tubular body PB. The pre-exterior plating process outer shape measuring device 130 has a central hole 131 in the axial direction. The central hole 131 has a substantially circular shape. The diameter of the central hole 131 is larger than the diameter of the tubular body PB.

[0112] The pre-exterior plating process outer shape measuring device 130 has a rotating body 132 and a base portion 133. The base portion 133 is provided at a fixed position with respect to the transport path. The rotating body 132 is disposed concentrically with the tubular body PB. During transport of the tubular body PB, the central axis of the tubular body PB may deviate from the central axis of the rotating body 132. The rotating body 132 can rotate with respect to the base portion 133.

[0113] Three distance sensors 135a, 135b, and 135c are provided on the rotating body 132 toward the central axis of the rotating body 132. The three distance sensors 135a, 135b, and 135c are distance sensor units that use laser light. The three distance sensors 135a, 135b, and 135c irradiate laser light toward the central axis of the rotating body 132 and measure the distance to the tubular body PB by receiving light reflected from the tubular body PB arranged in the central hole 131.

[0114] Rotating body 132 has a gear 136 on its outer circumferential surface. Base portion 133 has a motor 137 and a gear 138. Gear 136 is engaged with gear 138. The rotational force of motor 137 is transmitted to gear 136 via gear 138, causing rotating body 132 to rotate.

[0115] As the rotor 132 rotates, the three distance sensors 135a, 135b, and 135c revolve around the tubular body PB. While revolving around the tubular body PB, the three distance sensors 135a, 135b, and 135c measure the distance to the tubular body PB and output a distance signal indicating the measured distance. The output distance signal is supplied to the control and determination unit 200 via a controller (not shown).

[0116] The three distance sensors 135a, 135b, and 135c are constantly rotating during measurement and emit distance signals by wireless communication. For example, short-range wireless communication such as Bluetooth (registered trademark) or infrared communication can be used. Note that an electrical connection may be formed using a movable contact such as a brush, and the distance signal may be output by wire.

[0117] In this manner, the distance to the tubular body PB being transported can be measured by the three rotating distance sensors 135a, 135b, 135c.

[0118] The control and judgment unit 200 acquires the outer shape of the tubular body PB before the outer plating process using the pre-exterior plating process outer shape measuring device 130. Similarly, the control and judgment unit 200 acquires the outer shape of the tubular body PB after the outer plating process using the post-exterior plating process outer shape measuring device 140. The control and judgment unit 200 can acquire the thickness of the plating formed by the outer plating process from the outer shape of the tubular body PB before the outer plating process and the outer shape of the tubular body PB after the outer plating process.

[0119] <Pre-coating Process Outer Shape Measuring Device 150 and Post-coating Process Outer Shape Measuring Device 160> The pre-coating process outer shape measuring device 150 is a device for measuring the outer shape of the tubular body PB before resin is applied (for example, parameters that characterize the shape of the tubular body PB, such as diameter and roundness). Specifically, the outer shape of the tubular body PB can be measured between the molding process by the sizing device 442 and the resin application process by the top coat device 520 ((5) shown in FIG. 2).

[0120] The post-coating process outer shape measuring device 160 is a device for measuring the outer shape of the tubular body PB after the resin is applied (for example, parameters that characterize the shape of the tubular body PB, such as diameter and roundness). Specifically, the outer shape of the tubular body PB can be measured between the drying process by the drying device 550 and the cutting process by the cutting device 560 ((6) shown in FIG. 2).

[0121] As shown in FIG. 9, the pre-coating process outer shape measuring device 150 and the post-coating process outer shape measuring device 160 have the same configuration as the pre-exterior plating process outer shape measuring device 130 and the post-exterior plating process outer shape measuring device 140 .

[0122] The control and judgment unit 200 acquires the outer shape of the tubular body PB before the resin is applied, using the pre-coating process outer shape measuring device 150. The control and judgment unit 200 acquires the outer shape of the tubular body PB after the resin is applied, using the post-coating process outer shape measuring device 160. The control and judgment unit 200 can acquire the thickness of the resin formed by the resin application process from the outer shape of the tubular body PB before the resin is applied and the outer shape of the tubular body PB after the resin is applied.

[0123] <<<Control and Determination Unit 200>>> FIG. 10 is a block diagram showing an outline of the configuration of the control / determination unit 200 and the control device.

[0124] The control / determination unit 200 has a calculation unit 210, a memory unit 220, an input / output unit 230, and a display unit 240. The calculation unit 210 is made up of a CPU (Central Processing Unit). The memory unit 220 is made up of a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), etc. The memory unit 220 may be anything that can readably store various programs and data. The input / output unit 230 is made up of an I / O port, a communication interface, etc. The communication interface has an interface for wired communication as well as wireless communication. The display unit is made up of a liquid crystal display, etc.

[0125] Fig. 11 is a flowchart showing the film thickness control process. A program is stored in the memory unit 220 of the control / determination unit 200, and is called and executed by the calculation unit 210. In the following, it is assumed that the steel pipe production system 10 has completed startup processes such as initialization and is operating steadily. The flowchart shown in Fig. 11 is repeatedly executed at predetermined timings.

[0126] First, the calculation unit 210 of the control and judgment unit 200 receives the plate thickness before the inner surface plating process signal output from the plate thickness measuring device 110 before the inner surface plating process, acquires the plate thickness before the inner surface plating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1111).

[0127] Next, the calculation unit 210 of the control and judgment unit 200 receives the plate thickness signal after the inner surface plating process output from the plate thickness measuring device 110 before the inner surface plating process, acquires the plate thickness after the inner surface plating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1113).

[0128] Next, the calculation unit 210 of the control and judgment unit 200 receives the outer shape before outer plating process output from the pre-inner plating process plate thickness measuring device 110, acquires the outer shape before outer plating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1115).

[0129] Next, the calculation unit 210 of the control and judgment unit 200 receives the outer shape signal after the outer plating process output from the pre-inner plating process plate thickness measuring device 110, acquires the outer shape after the outer plating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1117).

[0130] Next, the calculation unit 210 of the control and judgment unit 200 receives the outer shape before outer coating process output from the pre-inner plating process plate thickness measuring device 110, acquires the outer shape before outer coating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1119).

[0131] Next, the calculation unit 210 of the control and judgment unit 200 receives the outer shape signal after the outer coating process output from the pre-inner plating process plate thickness measuring device 110, acquires the outer shape after the outer coating process, and stores it in the memory unit 220 of the control and judgment unit 200 (step S1121).

[0132] The above-mentioned sheet thickness signal before inner plating process, sheet thickness signal after inner plating process, outline signal before outer plating process, outline signal after outer plating process, outline signal before outer coating process, and outline signal after outer coating process are all previously waveform-shaped by various kinds of signal processing such as filtering, and long wavelength displacements such as undulations and deflections of the steel sheet SS and the tubular body PB, and short wavelength displacements such as irregularities and scratches, are removed. These signals may be analog signals or digital signals. In the case of analog signals, they may be converted into digital signals in advance by an AD converter.

[0133] Next, the calculation unit 210 of the control / determination unit 200 calculates the position corresponding to the inner surface plating process (step S1123). This is a process for associating the position in the longitudinal direction LD of the steel sheet SS at which the thickness is measured by the sheet thickness measuring device 110 before the inner surface plating process with the position in the longitudinal direction LD of the steel sheet SS at which the thickness is measured by the sheet thickness measuring device 120 after the inner surface plating process.

[0134] Specifically, the measurement positions can be associated by calculating the time IT (= IT2-IT1) from the distance SL (Figure 12(a)) between the pre-inner plating process sheet thickness measuring device 110 and the post-inner plating process sheet thickness measuring device 120 and the conveying speed TV of the steel sheet SS, from when a given position in the longitudinal direction LD on the steel sheet SS passes the pre-inner plating process sheet thickness measuring device 110 (IT1) to when it reaches and passes the post-inner plating process sheet thickness measuring device 120 (IT2).

[0135] As described above, the plate thickness measuring device 110 before the inner plating process and the plate thickness measuring device 120 after the inner plating process measure the plate thickness while moving back and forth in the width direction WD. It is also assumed that the measurement position of the plate thickness measuring device 110 before the inner plating process and the measurement position of the plate thickness measuring device 120 after the inner plating process cannot be matched. For this reason, instead of making the positions correspond to each other, it is sufficient to make the area measured by the plate thickness measuring device 110 before the inner plating process over a certain length along the longitudinal direction LD correspond to the area measured by the plate thickness measuring device 120 after the inner plating process over a certain length along the longitudinal direction LD. In this way, the plate thickness averaged over a certain length can be obtained.

[0136] Next, the calculation unit 210 of the control / determination unit 200 calculates the outer plating process corresponding position (step S1125). This is a process for associating the position in the longitudinal direction LD of the steel sheet SS whose thickness was measured by the pre-exterior plating process outer shape measuring device 130 with the position in the longitudinal direction LD of the steel sheet SS whose thickness was measured by the post-exterior plating process outer shape measuring device 140.

[0137] Specifically, the measurement positions can be associated by calculating the time OT (=OT2-OT1) from the time when a given position in the longitudinal direction LD on the tubular body PB passes the pre-external plating process external shape measuring device 130 (OT1) to the time when it reaches and passes the post-external plating process external shape measuring device 140 (OT2) based on the distance PL (Figure 12(b)) between the pre-external plating process external shape measuring device 130 and the post-external plating process external shape measuring device 140 and the conveying speed TV of the tubular body PB.

[0138] As described above, the pre-plating outer shape measuring device 130 and the post-plating outer shape measuring device 140 measure the outer shape while rotating around the tubular body PB. There are cases where the measurement position of the pre-plating outer shape measuring device 130 and the measurement position of the post-plating outer shape measuring device 140 cannot be matched. For this reason, instead of matching positions, it is sufficient to match the area measured by the pre-plating outer shape measuring device 130 over a certain length along the longitudinal direction LD with the area measured by the post-plating outer shape measuring device 140 over a certain length along the longitudinal direction LD. In this way, it is possible to obtain an outer shape averaged over a certain length.

[0139] Next, the calculation unit 210 of the control / determination unit 200 calculates an outer surface coating process corresponding position (step S1127). This is a process for associating the position in the longitudinal direction LD of the steel sheet SS whose thickness has been measured by the pre-coating process outer shape measuring device 150 with the position in the longitudinal direction LD of the steel sheet SS whose thickness has been measured by the post-coating process outer shape measuring device 160.

[0140] Specifically, the measurement positions can be associated by calculating the time RT (=RT2-RT1) from when a given position in the longitudinal direction LD on the tubular body PB passes the pre-coating process outer shape measuring device 150 (RT1) to when it reaches and passes the post-coating process outer shape measuring device 160 (RT2) from the distance PL (FIG. 12(b)) between the pre-coating process outer shape measuring device 150 and the post-coating process outer shape measuring device 160 and the conveying speed TV of the tubular body PB. Note that, for the sake of convenience, FIG. 12(b) shows the pre-coating process outer shape measuring device 130 as replaceable with the pre-coating process outer shape measuring device 150 and the post-coating process outer shape measuring device 140 as replaceable with the post-coating process outer shape measuring device 160.

[0141] As described above, the pre-coating outer shape measuring device 150 and the post-coating outer shape measuring device 160 measure the outer shape while rotating around the tubular body PB. There may be cases where the measurement position of the pre-coating outer shape measuring device 150 and the measurement position of the post-coating outer shape measuring device 160 cannot be matched. For this reason, instead of associating the positions, it is sufficient to associate the area measured by the pre-coating outer shape measuring device 150 over a certain length along the longitudinal direction LD with the area measured by the post-coating outer shape measuring device 160 over a certain length along the longitudinal direction LD. In this way, it is possible to obtain an outer shape averaged over a certain length.

[0142] Next, the calculation unit 210 of the control / judgment unit 200 calculates the inner plating film thickness due to the inner plating process for the inner plating process corresponding position associated in the processing of step S1123 from the difference between the sheet thickness of the steel sheet SS before the inner plating process and the sheet thickness of the steel sheet SS after the inner plating process (step S1129).

[0143] Next, the calculation unit 210 of the control / judgment unit 200 calculates the outer plating film thickness due to the outer plating process for the outer plating process corresponding position associated in the processing of step S1125 from the difference between the outer shape of the tubular body PB before the outer plating process and the outer shape of the tubular body PB after the outer plating process (step S1131).

[0144] Next, the calculation unit 210 of the control / judgment unit 200 calculates the resin film thickness due to the coating process for the outer surface coating process corresponding position associated in the processing of step S1127 from the difference between the outer shape of the tubular body PB before the coating process and the outer shape of the tubular body PB after the coating process (step S1133).

[0145] Next, the calculation unit 210 of the control / determination unit 200 determines whether the inner surface plating film thickness, the outer surface plating film thickness, and the resin film thickness are within a controllable range (step S1135).

[0146] When the calculation unit 210 of the control / judgment unit 200 judges in the judgment process of step S1135 that the inner surface plating film thickness, the outer surface plating film thickness, and the resin film thickness are within the controllable range (YES), it determines the control parameters according to the values ​​of the inner surface plating film thickness, the outer surface plating film thickness, and the resin film thickness (step S1137).

[0147] The control parameters related to the inner surface plating process are as follows. The first heating temperature is a control parameter of the heating process of the first heating device 314. The temperature of the molten metal is a control parameter of the inner surface plating device 320. The distance from the first pouring part 324 to the first wiping part 332, the distance from the first wiping part 332 to the steel sheet SS, and the inclination of the wiping part with respect to the first face FF of the steel sheet SS are control parameters of the inner surface plating process of the inner surface plating device 320. The position of the first pouring part 324 is also a control parameter. The flow rate and flow rate distribution of the gas discharged from the first wiping part 332 are control parameters of the inner surface plating process.

[0148] When adjusting the distance from first pouring portion 324 to first wiping portion 332, the position of first pouring portion 324 or the position of first wiping portion 332 may be adjusted.

[0149] In the process of step S1137, when the inner surface plating film thickness is to be adjusted, one of these control parameters is selected.

[0150] The control parameters related to the outer plating process are as follows. The second heating temperature is a control parameter of the heating process. The temperature of the molten metal is a control parameter of the outer plating device 420. The number of immersion units 426 to be operated can also be a control parameter of the outer plating device 420. The distance from the immersion unit 426 to the second wiping unit 432, the distance in the width direction WD from the second wiping unit 432 to the outer periphery of the tubular body PB, and the distance in the distance direction PD from the second wiping unit 432 to the outer periphery of the tubular body PB are control parameters of the outer plating process. The flow rate and flow rate distribution of the gas discharged from the second wiping unit 432 are control parameters of the outer plating process.

[0151] When adjusting the distance from immersed section 426 to second wiping section 432, the position of second wiping section 432, immersed section 426 to be operated, or the position of immersed section 426 may be adjusted.

[0152] In the process of step S1137, when adjusting the outer surface plating thickness, one of these control parameters is selected.

[0153] The control parameters related to the resin coating process are as follows. The distance from the top coat device 520 to the third wiping unit 532, the distance in the width direction WD from the third wiping unit 532 to the outer periphery of the tubular body PB, and the distance in the distance direction PD from the third wiping unit 532 to the outer periphery of the tubular body PB are control parameters of the resin layer. The flow rate and flow rate distribution of the gas discharged from the third wiping unit 532 are control parameters of the resin layer.

[0154] In the process of step S1137, when adjusting the resin film thickness, one of these control parameters is selected.

[0155] The control parameters related to the entire process are as follows. The transport speed is a control parameter that controls the plating time of the inner surface plating and the outer surface plating. In the process of step S1137, when the inner surface plating film thickness, the outer surface plating film thickness, and the resin film thickness are to be adjusted in common, the transport speed is selected.

[0156] Next, calculation unit 210 of control / determination unit 200 determines a target control value for the control parameter determined in the process of step S1137 (step S1139). For example, if the determined control parameter is the first heating temperature, a target temperature is determined. Also, if the determined control parameter is the distance from first pouring unit 324 to first wiping unit 332, a target distance is determined.

[0157] Next, the calculation unit 210 of the control / determination unit 200 outputs the control values ​​determined in the process of step S1139 to each device (step S1141), and ends this subroutine.

[0158] When the calculation unit 210 of the control / judgment unit 200 determines in the judgment process of step S1135 that the inner surface plating film thickness, the outer surface plating film thickness, and the resin film thickness are not within the controllable range (NO), it determines that they are not controllable and displays an error message on the display unit 240 (step S1143), and ends this subroutine.

[0159] <<<Other embodiments>>> In the above-described embodiment, an example was shown in which an inner surface plating process is performed, and the thickness of the inner surface plating is obtained by the inner surface plating process pre-plate thickness measuring device 110 and the inner surface plating process post-plate thickness measuring device 120, an outer surface plating process is performed, and the thickness of the outer surface plating is obtained by the outer surface plating process pre-surface outer shape measuring device 130 and the outer surface plating process post-surface outer shape measuring device 140, a coating process is performed, and the coating film thickness is obtained by the coating process pre-surface outer shape measuring device 150 and the coating process post-surface outer shape measuring device 160. The processes and measurements are not limited to these. Each of the following combinations can be accommodated.

[0160] 1.Only perform inner surface plating. 2. The inner surface is plated to obtain the thickness of the inner surface plating. 3. Only the exterior surface is plated. 4. The outer surface is plated to obtain the thickness of the outer surface plating. 5. Only apply coating. 6. The coating process is performed and the coating thickness is obtained. 7. Perform inner and outer plating treatment. 8. Inner surface plating and outer surface plating are performed to obtain the inner surface plating thickness. 9. The inner and outer plating processes are performed to obtain the thickness of the outer plating. 10. Inner surface plating and outer surface plating are performed to obtain the inner surface plating thickness and outer surface plating thickness. 11. Perform inner plating and coating processes. 12. The inner surface plating and coating processes are performed to obtain the thickness of the inner surface plating. 13. The inner surface is plated and coated to obtain the coating thickness. 14. The inner surface plating process and coating process are performed to obtain the thickness of the inner surface plating and the thickness of the coating film. 15.External plating and coating processes are performed. 16. The outer plating and coating processes are performed to obtain the thickness of the outer plating. 17. The exterior plating and coating processes are performed to obtain the coating thickness. 18. The outer surface plating and coating processes are performed to obtain the thickness of the outer surface plating and the thickness of the coating film. 19. Perform internal plating, external plating and coating processes. 20. The thickness of the inner plating is obtained by performing inner plating, outer plating and coating processes. 21. The thickness of the outer plating is obtained by performing inner plating, outer plating and coating processes. 22. Perform inner surface plating, outer surface plating and coating processes to obtain the coating thickness. 23. The inner surface plating process, the outer surface plating process and the coating process are performed to obtain the inner surface plating thickness and the outer surface plating thickness. 24. Perform inner surface plating, outer surface plating and coating processes to obtain the inner surface plating thickness and coating film thickness. 25. Perform inner surface plating, outer surface plating and coating processes to obtain the thickness of the outer plating and the thickness of the coating film. 26. Perform inner surface plating, outer surface plating and coating processes to obtain the inner surface plating thickness, outer surface plating thickness and coating film thickness. The 26th combination is the combination of this embodiment.

[0161] For example, by omitting the steps from the cleaning step by the first cleaning device 312 to the cooling step by the first cooling device 340 in Fig. 2, it is possible to perform only the outer plating process without performing the inner plating process. Similarly, by omitting the steps from the cleaning step by the second cleaning device 412 to the cooling step by the second cooling device 440 in Fig. 2, it is possible to perform only the inner plating process without performing the outer plating process.

[0162] In the above-mentioned combinations 1 to 26, the sheet thickness before the inner plating process and the sheet thickness after the inner plating process were measured before and after the inner plating process, but it is also possible to measure the sheet thickness either before or after. Similarly, before and after the outer plating process, the outer shape before the outer plating process and the outer shape after the outer plating process were measured, but it is also possible to measure the outer shape either before or after. Furthermore, before and after the coating process, the outer shape before the coating process and the outer shape after the coating process were measured, but it is also possible to measure the outer shape either before or after.

[0163] Furthermore, for each of the combinations 1 to 26 described above, a thickness measurement may be added after the treatment by the pretreatment device 310 or the treatment by the first cleaning device 312. The state of the steel sheet SS at the stage before each treatment can be obtained.

[0164] <Pre-inner plating processing sheet thickness measuring device 110 and post-inner plating processing sheet thickness measuring device 120> The sheet thickness measuring device 110 before inner surface plating process and the sheet thickness measuring device 120 after inner surface plating process (hereinafter simply referred to as the sheet thickness measuring device 110 before inner surface plating process) can measure the sheet thickness and the thickness variation of the steel sheet SS separately from the plating process, and can also detect scratches, dents, etc. of the steel sheet SS. Measurement by the sheet thickness measuring device 110 before inner surface plating process may be performed before the processing by the forming device 342.

[0165] <External Surface Pre-Plating Process Outer Shape Measuring Device 130 and External Surface Post-Plating Process Outer Shape Measuring Device 140> The pre-exterior plating process outer shape measuring device 130 and the post-exterior plating process outer shape measuring device 140 (hereinafter simply referred to as pre-exterior plating process outer shape measuring device 130) can measure the outer shape of the tubular body PB, the variation in the outer shape of the tubular body PB, and the deviation of the tubular body PB from a perfect circle, separately from the plating process, as well as detect scratches, dents, etc. on the outer surface of the tubular body PB. Measurement by the pre-exterior plating process outer shape measuring device 130 may be performed before processing by the sizing device 442.

[0166] <Pre-inner plating treatment sheet thickness measuring device 110 and / or pre-outer plating treatment outer shape measuring device 130> It is possible to perform both measurements using the sheet thickness measuring device 110 before inner plating process and the measurement using the outer shape measuring device 130 before outer plating process, or to perform only one of them. That is, the sheet thickness etc. of the steel sheet SS may be measured using the sheet thickness measuring device 110 before inner plating process, and the outer shape etc. of the tubular body PB may be measured using the outer shape measuring device 130 before outer plating process. Also, it is possible to measure only the sheet thickness etc. of the steel sheet SS using only the sheet thickness measuring device 110 before inner plating process. It is also possible to measure only the outer shape etc. of the tubular body PB using only the outer shape measuring device 130 before outer plating process. Appropriate selection can be made according to what is required.

[0167] <Unplated or plated> When an unplated steel sheet SS is used, it is possible to measure the thickness of the steel sheet SS in an unplated state, the outer shape of the tubular body PB in an unplated state, etc. Also, by using a steel sheet SS in which both the first face FF and the second face SF are plated in advance, it is possible to measure the thickness of the steel sheet SS in a plated state, and the outer shape of the tubular body PB in a plated state, etc.

[0168] <<<<Modifications>>> In the above example, the resin is applied to the outer surface OF of the tubular body PB by the top coat device 520, but the material to be applied is not limited to resin. For example, any material that has fluidity and can cover the outer surface OF of the tubular body PB can be applied to the outer surface OF of the tubular body PB.

[0169] <<<<<Scope of this embodiment>>>> As described above, the present invention has been described with reference to the present embodiment, but the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. Thus, the present invention includes various embodiments not described herein. [Explanation of symbols]

[0170] 10. Steel Pipe Manufacturing System 110 Inner surface thickness measurement device before plating 120 Inner surface plating process post-thickness measuring device 130 External shape measuring device before external plating processing 140 External shape measuring device after external plating process 150 Pre-coating process external shape measuring device 160 Apparatus for measuring external shape after coating process 320 Inner surface plating equipment 420 External plating equipment 520 Topcoat device

Claims

1. a forming device for continuously forming a tubular body from a plate-shaped steel sheet having a first surface and a second surface opposite to the first surface, the first surface being an inner surface and the second surface being an outer surface; At least one of a steel plate processing section that processes the steel plate and a tubular body processing section that processes the tubular body, The steel plate processing section includes: a steel sheet plating processing section that applies plating to the first surface of the steel sheet; a steel sheet thickness measuring unit that measures the thickness of the steel sheet before and after a first plating process by the steel sheet plating processing unit; a first plating thickness determination unit that determines whether or not a plating thickness in the first plating process is within a controllable range based on a difference between a sheet thickness before the first plating process and a sheet thickness after the first plating process, and determines a control parameter for the steel sheet plating processing unit when the plating thickness in the first plating process is within the controllable range; While continuously moving the steel sheet, the processing of the steel sheet plating processing unit and the processing of the steel sheet thickness measuring unit are performed on the steel sheet at different positions along the movement of the steel sheet, and the processing of the first plating film thickness determining unit is continuously performed; The tubular body processing section includes: a tubular body plating processing section that performs plating on the second surface of the tubular body after the steel plate is formed into the tubular body by the forming device; a tubular body outer diameter measuring unit that measures the outer diameter of the tubular body before and after a second plating process by the tubular body plating processing unit; and a second plating thickness determination unit that determines whether or not the plating thickness of the second plating process is within a controllable range based on the difference between the outer diameter before the second plating process and the outer diameter after the second plating process, and determines a control parameter for the tubular body plating processing unit when the plating thickness of the second plating process is within the controllable range; A steel pipe manufacturing system in which the tubular body is continuously moved, processing by the tubular body plating processing unit and the tubular body outer diameter measurement unit is performed on the tubular body at different positions along the movement of the tubular body, and processing by the second plating film thickness determination unit is continuously performed.

2. The steel sheet plating processing section has a first plating device that applies plating to the first surface, The steel plate thickness measuring unit includes: A first thickness measuring device that measures the thickness of the steel sheet before the first plating process; A second thickness measuring device that measures the thickness of the steel sheet after the first plating process; The steel pipe manufacturing system according to claim 1 ,

3. The tubular body plating processing unit further includes a second plating device that applies plating to the outer surface of the tubular body, The tubular body outer diameter measuring unit includes: a first outer diameter measuring device that measures an outer diameter of the tubular body before a second plating step by the second plating device; 3. A steel pipe manufacturing system according to claim 1 or 2, further comprising: a second outer diameter measuring device that measures the outer diameter of the tubular body after the second plating step by the second plating device.

4. a first film thickness adjusting device for adjusting a plating film thickness by removing excess of the molten material used in the first plating step; The steel pipe manufacturing system according to claim 2 , further comprising a first film thickness control device that controls the first film thickness adjustment device based on the control parameters determined by the first plating film thickness determination unit.

5. a second film thickness adjusting device for adjusting a plating film thickness by removing excess of the molten material used in the second plating step; The steel pipe manufacturing system according to claim 3 , further comprising a second film thickness control device that controls the second film thickness adjustment device based on the control parameters determined by the second plating film thickness determination unit.

6. A coating device for forming a coating film on the outer surface; a coating outer diameter measuring unit for measuring an outer diameter of the tubular body before and after the coating process by the coating device; A steel pipe manufacturing system as described in any one of claims 1 to 5, further comprising a coating thickness determination unit which determines whether the coating thickness is within a controllable range from the difference between the outer diameter before coating and the outer diameter after coating, and if the coating thickness is within the controllable range, determines control parameters related to the coating process.

7. a coating thickness adjusting device for adjusting the thickness of the coating film by removing excess from the coating film in the coating process; The steel pipe manufacturing system according to claim 6 , further comprising a coating thickness control device that controls the coating thickness adjustment device based on the control parameters determined by the coating thickness determination unit.

8. a forming device for continuously forming a tubular body from a plate-shaped steel sheet having a first surface and a second surface opposite to the first surface, the first surface being an inner surface and the second surface being an outer surface; a coating device for forming a coating film on the outer surface of the molded tubular body; a coating outer diameter measuring unit for measuring an outer diameter of the tubular body before and after the coating process by the coating device; a coating thickness determination unit that determines whether or not a coating thickness is within a controllable range based on a difference between an outer diameter before coating and an outer diameter after coating, and determines a control parameter for forming a coating film by the coating device when the coating thickness is within the controllable range; A steel pipe manufacturing system in which the tubular body is continuously moved while the processing of the coating device and the coating outer diameter measurement unit is performed on the tubular body at different positions along the movement of the tubular body, and the processing of the coating film thickness determination unit is continuously performed.

9. a coating thickness adjusting device for adjusting a thickness of the coating film by removing excess of the coating film in the coating process; The steel pipe manufacturing system according to claim 8, further comprising a coating thickness control device that controls the coating thickness adjustment device based on the control parameters determined by the coating thickness determination unit.

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