Rool forming steel pipe manufacturing method

Abstract

The present invention relates to a method for manufacturing a roll-formed steel pipe, comprising: a metal sheet supply step for supplying a metal sheet of a predetermined material; a metal sheet cutting step for cutting the metal sheet supplied in the metal sheet supply step to a predetermined size; a forming step for feeding the cut metal sheet into a roll-forming machine to manufacture it into a predetermined steel pipe shape; a welding step for welding the roll-formed steel pipe formed in the forming step; a post-processing step for performing post-processing on the inside and outside of the welded roll-formed steel pipe; and a determination step for determining the condition of the roll-forming machine and whether the post-processed roll-formed steel pipe is of good quality.

Description

Technology Field

[0001] The present invention relates to a manufacturing process for processing metal materials using rollers, and more specifically, to a method for manufacturing a roll-formed steel pipe by feeding a metal sheet into a roll-forming machine containing a plurality of rollers to adjust its shape and process it into a specific shape. Background Technology

[0003] Door frames for existing construction equipment such as forklifts, excavators, and wheel loaders are manufactured through a process involving pipe production via drawing, CO2 welding of steel plates onto the pipes, finishing work on the weld bead lines, bending work using a bending machine, and angle cutting with a band saw. During the assembly process, door frames can also be manufactured by repeating finishing work using argon or CO2 welding.

[0004] However, when manufacturing door frames in the manner described above, there are numerous factors that can lead to defects, such as impacts during transportation due to the many processes, lack of worker proficiency, and the disposal of all subsequently produced door frames if a single piece of equipment fails; furthermore, the multi-step process requires significant time and skilled workers.

[0005] Furthermore, the response to various issues arising from each process unit becomes diversified, which leads to increased production costs and can undermine competitiveness.

[0006] Therefore, research is required on a method for manufacturing roll-formed steel pipes to mass-produce high-quality, high-efficiency, low-cost, and various types of metal door frames using a roll-forming system composed of a roll-forming machine that performs roll forming on existing metal materials, forming tools corresponding to door frames, heating devices, control devices, and pressure devices. Prior art literature

[0008] Korean Registered Patent No. 10-1028118 The problem to be solved

[0009] The present invention aims to reduce the time and cost required for the manufacturing process by manufacturing door frames and steel pipes using a roll forming machine.

[0010] In addition, the purpose is to reduce the defect rate by rapidly diagnosing sensor failures using data collected from sensors installed in the roll forming machine.

[0011] In addition, the purpose is to quickly identify whether a product is defective during the production process by digitizing forming data collected from the roll forming machine and defects collected from welding and surfaces to calculate a comprehensive defect score. means of solving the problem

[0013] A method for manufacturing a roll-formed steel pipe according to one embodiment of the present invention may include a metal sheet supply step of supplying a metal sheet of a predetermined material; a metal sheet cutting step of cutting the metal sheet supplied in the metal sheet supply step to a predetermined size; a forming step of feeding the cut metal sheet into a roll-forming machine to manufacture it into a predetermined steel pipe shape; a welding step of welding the roll-formed steel pipe formed in the forming step; a post-processing step of performing post-processing on the inside and outside of the welded roll-formed steel pipe; and a determination step of determining the state of the roll-forming machine and whether the post-processed roll-formed steel pipe is a good product.

[0014] In addition, the forming step may perform forming of the metal sheet fed using the roll forming machine, and may collect forming data including the dimensions of the metal sheet fed, the pressure of the roller, the welding quality, and the forming time per metal sheet.

[0015] In addition, the welding step involves performing a welding process using an automatic welding device after fixing the roll-formed steel pipe, applying pre-set welding parameters corresponding to the shape and material of the roll-formed steel pipe, and monitoring the temperature of the welding area and the progress of the welding.

[0016] In addition, the above post-processing step may include a surface treatment step for polishing the surface of the steel pipe welded in the welding step and removing welding dubbing, a heat treatment step for performing a heat treatment of heating the welded roll-formed steel pipe to a preset temperature, and a coating step for performing a coating on the surface of the welded steel pipe.

[0017] In addition, the above judgment step uses the forming data to determine the overall defect score (SF) according to the following [Mathematical Formula 1]. score Calculate ) and,

[0018] [Mathematical Formula 1]

[0019]

[0020] (Here, MS fp is the metal sheet dimensional defect rate, P fp is the average pressure failure rate of the roller, W fp is the welding quality defect rate, FT fp represents the forming time variation rate)

[0021] If the above total defect score exceeds a preset range, it may be determined to be defective. Effects of the invention

[0023] According to the present invention, by manufacturing a door frame and a steel pipe using a roll forming machine, the time and cost required for the manufacturing process can be reduced.

[0024] In addition, by using data collected from sensors installed in the roll forming machine to diagnose whether a sensor is faulty, the failure rate can be reduced by rapidly diagnosing sensor failures.

[0025] In addition, by converting forming data collected from roll forming machines and defects collected from welding and surfaces into data to calculate a comprehensive defect score, it is possible to quickly identify whether a product is defective during the production process. Brief explanation of the drawing

[0027] FIG. 1 is a flowchart illustrating a method for manufacturing a roll-formed steel pipe according to an embodiment of the present invention. FIG. 2 is a diagram showing an intermediate block diagram of a post-processing step in a roll-forming steel pipe manufacturing method according to an embodiment of the present invention. Specific details for implementing the invention

[0028] Specific details regarding the problem to be solved, the means for solving the problem, and the effects of the invention as described above are included in the embodiments and drawings to be described below. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings.

[0029] The scope of the present invention is not limited to the embodiments described below, and various modifications can be made by those skilled in the art within the scope of the technical essence of the present invention.

[0030] Hereinafter, the method for manufacturing a roll-formed steel pipe according to the present invention will be explained in detail with reference to the attached FIGS. 1 and 2.

[0031] First, FIG. 1 is a flowchart illustrating a method for manufacturing a roll-formed steel pipe according to an embodiment of the present invention, and FIG. 2 is an intermediate block diagram illustrating a post-processing step within a method for manufacturing a roll-formed steel pipe according to an embodiment of the present invention.

[0032] Referring to FIG. 1, a method for manufacturing a roll-formed steel pipe according to an embodiment of the present invention may include a metal sheet supply step (110), a metal sheet cutting step (120), a forming step (130), a welding step (140), a post-processing step (150), and a judgment step (160).

[0033] The above metal sheet supply step (110) can supply a metal sheet of a preset material.

[0034] More specifically, the metal sheet supply step (110) feeds the metal sheet coil into an uncoiler, and the uncoiler unwinds the metal sheet coil and supplies it in a continuous length to a line leading to the metal sheet cutting step (120).

[0035] Here, the material of the metal sheet coil supplied to the metal sheet supply step (110) may be steel, aluminum, stainless steel, copper, alloy, etc., and the material of the metal sheet coil may be supplied according to the purpose of use, application, and planned shape of the manufacturing target.

[0036] In addition, the metal sheet supply step (110) may further provide an RFID tag, a barcode scanner, a weight measuring device, an automatic material detection sensor, etc., in response to the input of the metal sheet coil to sense the material of the input metal sheet coil.

[0037] The metal sheet cutting step (120) can cut the metal sheet supplied in the metal sheet supply step (110) to a preset size.

[0038] More specifically, the metal sheet cutting step (120) can cut the metal sheet supplied from the metal sheet supply step (110) according to specifications set by the manager and transfer it to a roll forming machine through a roll forming line.

[0039] Here, the metal sheet cutting step (120) performs shearing of the metal sheet supplied by uncoiling in the metal sheet supply step (110) to a preset length for cutting the metal sheet, wherein the preset length can be freely changed according to the use of the steel pipe being manufactured.

[0040] For example, if the steel pipe manufactured by performing roll forming is a circular steel pipe with a diameter of 50 mm and a thickness of 2 mm, it can be cut to a size of 5 m in width, 50 mm in length, and 100 mm in width in the rapid sheet cutting step (120).

[0041] In addition, the metal sheet cutting step (120) may further perform press blanking, which involves applying pressure with a press (hydraulic press, mechanical press, etc.) to a mold having a specific shape and space to process the metal sheet into the shape of the mold, in cases where a specific shape or hole needs to be formed within the metal sheet in response to the manager's settings.

[0042] Meanwhile, in the metal sheet cutting step (120) above, the device used for cutting and shearing the metal sheet is an electronic shearing machine, sheet metal shears, a cutting machine, a laser cutting machine, a cut-off machine, etc., and can perform accurate cutting of the metal sheet in accordance with the specifications set by the manager.

[0043] Additionally, in the case where the metal sheet cutting step (120) is a process in which the supplied metal sheet is required to be separated into two or more products, a double-ending process may be further performed in which one end of the metal sheet is cut and the remaining part is divided into two or more products.

[0044] At this time, when the above double ending process is performed, the metal sheet cutting step (120) may further include an ending machine that processes the end portion of the metal sheet with high precision, an ending clip that firmly fixes the end portion of the metal sheet, a double ender that connects the two ends of the metal sheet, a looper that transports the metal sheet, a roll that winds and stores the metal sheet, and a trimmer that cuts the end portion of the metal sheet.

[0045] The above forming step (130) can be manufactured into a predetermined steel pipe shape by feeding the cut metal sheet into a roll forming machine.

[0046] Here, the forming step (130) can perform roll forming by feeding the metal sheet cut in the metal sheet cutting step (120) into a roll forming machine using a feeder.

[0047] At this time, the roll forming machine is equipment that performs roll forming processing on a supplied metal sheet into a shape set by a manager, and a series of rollers can continuously bend and form the metal sheet to form it.

[0048] Here, the roll forming machine is equipped with a laser welder for welding the formed steel pipe, a cutoff cutter for cutting the formed steel pipe, an angle cutter for cutting at a specific angle, bending rolls for modifying the shape of the steel pipe or imparting curvature, and a control panel for monitoring and controlling the operation of the forming line, thereby enabling roll forming of the supplied metal sheet.

[0049] For example, the roll forming machine described above may be configured such that the number of 'stages' (number of rollers) using rollers is provided in a manner that the number of stages is 30, laser welding using a laser welder is performed at the 25th stage, four bending rolls are provided after the 30th stage to perform roll bending operations, and then cutting is performed using a cut-off cutter and an angle cutter.

[0050] Meanwhile, in the above forming step (130), the roll forming machine may further be equipped with sensors and image capturing devices pre-set inside and outside to collect additional data for improving and monitoring the quality of the roll-formed steel pipe.

[0051] Here, the aforementioned preset sensors may include a pressure sensor for measuring the pressure value of a roller in a roll forming machine, a position sensor for detecting the position of a metal sheet being roll formed, a speed sensor for measuring the speed of a roller and a moving material that perform rotation or forward / backward movement in a roll forming machine, a temperature sensor for measuring heat, metal sheet, motor temperature, and internal / external temperature generated during the roll forming process, a length sensor for measuring the length of the input metal sheet and the roll-formed steel pipe, a laser sensor for evaluating surface defects, errors, welding consistency, and welding quality of the formed roll-formed steel pipe, a timer for measuring process time, etc.

[0052] Through this, the forming step (130) performs forming of the metal sheet fed using the roll forming machine, and can collect forming data including the dimensions of the metal sheet fed, the pressure of the roller, the welding quality, and the forming time per metal sheet.

[0053] The welding step (140) can weld the roll-formed steel pipe formed in the forming step (130).

[0054] Here, the welding step (140) can be performed using an automatic welding device after fixing the roll forming steel pipe.

[0055] More specifically, in the welding step (140), the roll-formed steel pipe formed through the roll-forming machine in the forming step (130) is transferred to a guide, and after identifying the position of the roll-formed steel pipe using a proximity sensor provided in the guide, automatic alignment and fixing are performed, and welding can be performed at a preset welding position using an automatic welding module.

[0056] Here, the above-mentioned preset welding position may be set differently depending on the shape and characteristics of the roll-formed steel pipe.

[0057] For example, if the roll-formed steel pipe is a door frame, the intersection point where the corner portions and components of the roll-formed steel pipe frame formed in the forming step (130) intersect can be set as the welding location so that welding is performed only on that part.

[0058] Meanwhile, the above automatic welding module may refer to a welding module in which a welding torch is attached to a robot arm or welding robot, welding power and shielding gas are supplied, and sensors and control systems required for automatic welding are included, and various parameters occurring during welding are measured and adjusted by a manager to ensure consistency and stability of welding.

[0059] Through this, the welding step (140) can apply pre-set welding parameters corresponding to the shape and material of the roll-formed steel pipe.

[0060] That is, when performing automatic welding of the roll-formed steel pipe in the welding step (140), automatic welding can be performed by applying parameters of the automatic welding module set by the manager in correspondence with the material of the metal sheet supplied in the metal sheet supply step (110) and the shape of the roll-formed steel pipe formed in the forming step (130).

[0061] For example, when the material of the supplied metal sheet is steel, the welding current is set to 100~200A, the welding voltage to 18~22V, the welding speed to 20cm / min~60cm / min, the welding shielding gas to a mixture of 80% argon and 20% CO2 gas, and the welding electrode spacing to a spacing between 2mm and 4mm, and when the material of the metal sheet is aluminum, the welding parameters are changed to a welding current to 100~250A, the welding voltage to 15~20V, the welding speed to 10cm / min~40cm / min, the welding shielding gas to 100% pure argon, and the welding electrode spacing to 1mm~3mm, so that welding can be performed using an automatic welding module.

[0062] In addition, the temperature of the welded area and the progress of the welding can be monitored during the welding step (140).

[0063] More specifically, in the welding step (140), a welding camera, a thermal imaging camera, a welding current and voltage monitoring device, an automatic welding module control device, and a welding data logging and analysis device may be further provided near the automatic welding module that automatically welds the roll-forming steel pipe to be welded, so that welding monitoring can be performed.

[0064] At this time, the welding camera displays the welding process inside and outside the roll-formed steel pipe on the screen to visually check the welding status, and the thermal imaging camera visualizes the heat distribution of the weld area to enable the detection and response to errors occurring during the welding process.

[0065] In addition, the welding current and voltage monitoring device monitors the welding current and voltage to evaluate welding stability and identify quality issues, the automatic welding module control device controls the movement of the automatic welding module and welding parameters per metal sheet, and the data logging and analysis device collects, records, and analyzes data generated during the welding process while simultaneously tracking welding quality and temperature changes at the welding site, which can be used as supporting data for identifying problems and providing improvement feedback when issues occur during the welding process.

[0066] The above post-processing step (150) can perform post-processing on the inside and outside of the welded roll-formed steel pipe.

[0067] Here, the post-processing step (150) is explained in more detail with reference to FIG. 2.

[0068] Referring to FIG. 2, the post-processing step (150) may include a surface treatment step (151), a heat treatment step (152), and a coating step (153).

[0069] The above surface treatment step (151) can remove polishing and welding dubbing from the surface of the steel pipe welded in the above welding step (140).

[0070] More specifically, the surface treatment step (151) may perform surface polishing to smoothly polish the surface of the roll-formed steel pipe through heat generation using a polishing liquid or water, welding dubbing removal to remove welding dubbing or welding fragments generated during the welding process, and surface cleaning to remove dust and contaminants from the surface.

[0071] Through this, the surface treatment step (151) can remove impurities and rust located at the welded portion of the welded roll-formed steel pipe and uniformly polish the welded portion.

[0072] Here, the surface treatment step (151) may further include an automatic polishing machine, an automatic welding dubbing removal device, an automatic surface finishing device, etc., which automatically perform surface polishing and welding dubbing removal for surface treatment of a roll-formed steel pipe.

[0073] At this time, the automatic polishing machine automatically polishes the surface of the welded roll-formed steel pipe to remove impurities or rust, and the manager performs programming in advance according to the dimensions and material of the roll-formed steel pipe so that the welded area is automatically polished according to the programmed operation system, and the automatic welding dubbing removal device can identify and automatically remove welding dubbing when the welded roll-formed steel pipe passes through.

[0074] In addition, the automatic surface cleaning device can automatically wipe the surface of the welded roll-formed steel pipe to remove dust and foreign substances from the surface.

[0075] Through the above, the surface treatment step (151) can perform surface polishing and dubbing removal of the welded roll-formed steel pipe with improved productivity and efficiency.

[0076] The above heat treatment step (152) can perform heat treatment by heating the welded roll-formed steel pipe to a preset temperature.

[0077] More specifically, the heat treatment step (152) can perform heat treatment through various heating methods on roll-formed steel pipes that are determined to be uniform and free of defects by inspecting for cracks and defects in the roll-formed steel pipes transferred after welding.

[0078] At this time, the inspection of cracks and defects in the roll-formed steel pipe may be performed using visual inspection by a manager or quality inspector with the naked eye, a fluid thermal expansion test in which defects are identified through a process in which liquid penetrant is applied and removed from the surface of the roll-formed steel pipe, fluid is infiltrated through an opening, and then colored penetrant fills the defect, an ultrasonic inspection in which defects are identified using ultrasound, a magnetic particle size inspection in which defects are found by applying magnetic particle size after applying a magnetic field, an X-ray inspection in which defects are identified through image analysis using X-ray imaging, and a radiographic inspection in which defects are determined by analyzing transmitted radiographic images using X-rays or gamma rays.

[0079] Meanwhile, the heat treatment step (152) can perform preheating and refining through sequence heat treatment after performing preheating of the roll-formed steel pipe determined to be free of cracks and defects to relieve internal stress.

[0080] Here, the hardening heat treatment changes the internal structure and improves strength by heating the roll-formed steel pipe to a high temperature, and refining can stabilize the properties of the roll-formed steel pipe and relieve internal stress through cooling after hardening.

[0081] Afterward, cooling is performed on the roll-formed steel pipe on which the above-mentioned sequencing heat treatment has been performed, and rehardening and refining may be performed according to the material or application of the roll-formed steel pipe to improve the properties of the welded parts within the roll-formed steel pipe and remove internal stress.

[0082] In addition, the heat treatment step (152) can perform heat treatment according to the material of the metal sheet that is the material of the roll-formed steel pipe.

[0083] For example, if the material of the roll-formed steel pipe is carbon steel, the pipe is heated at a high temperature and refining is performed at an appropriate temperature after hardening; if it is an aluminum alloy, strength is improved through artificial aging treatment after hardening, and heat treatment through quenching and artificial aging can be performed by heating at a constant temperature, rapidly cooling, and then niting (natural aging) at a low temperature.

[0084] The above coating step (153) can perform a coating on the surface of the welded steel pipe.

[0085] More specifically, the coating step (153) can improve corrosion resistance and internal performance by performing a preset coating treatment on a heat-treated roll-formed steel pipe.

[0086] Here, the aforementioned pre-set coating treatment may refer to coating treatments such as galvanizing to prevent corrosion and oxidation, paint coating for decorative effects and protection against corrosion and chemical damage, epoxy coating to improve corrosion resistance and durability, galvanizing to improve the durability of the roll-formed steel pipe by providing a thick coating, and aluminum plating for corrosion resistance and aesthetic effects, although these may vary depending on the material of the roll-formed steel pipe.

[0087] At this time, the coating step (153) can perform automated coating processing by further providing an automatic plating line, an automatic paint spray system, an automatic epoxy coating line, and an automatic soft plating line for the automation of coating of roll-formed steel pipes.

[0088] Referring again to FIG. 1, the judgment step (160) can determine the condition of the roll forming machine and whether the post-processed roll forming steel pipe is of good quality.

[0089] That is, the above judgment step (160) calculates a comprehensive defect score using the forming data, and if the comprehensive defect score exceeds a preset range, it can be determined to be defective.

[0090] More specifically, the judgment step (160) uses the difference between the forming data, which includes the dimensions of the metal sheet fed in the forming step (130), the pressure of the roller, the welding quality, and the forming time per metal sheet, and the previously stored reference forming data to determine the overall defect score (SF score Calculate ) and the above overall defective score (SF score If ) falls outside the preset range, the quality of the roll-formed steel pipe can be judged as defective.

[0091] Here, the above-mentioned preset range is the overall defect score (SF score The value can be set from a minimum of 0 to a maximum of 100 as a range for determining whether there is a defect, and is generally set between 1 and 5 by the manager, but can be freely changed within the range of 0 to 100 depending on the characteristics of the roll-formed steel pipe being manufactured.

[0092] Meanwhile, in the above judgment step (160), the overall defective score (SF score ) can be calculated according to the following [Mathematical Formula 1].

[0093] [Mathematical Formula 1]

[0094]

[0095] (Here, MS fp is the metal sheet dimensional defect rate, P fp is the average pressure failure rate of the roller, W fp is the welding quality defect rate, FT fp represents the forming time variation rate)

[0096] At this time, the determination step (160) uses the width, length, and depth of the metal sheet measured using a metal sheet dimension measuring sensor in the roll forming machine and the previously stored reference dimensions of the metal sheet and the roll forming steel pipe being manufactured to determine the metal sheet dimension defect rate (MS fp ) can be calculated according to [Mathematical Formula 2].

[0097] [Mathematical Formula 2]

[0098]

[0099] (Here, MS sw is the standard horizontal length of the metal sheet, MS aw is the measured horizontal length of the metal sheet, MS sv is the standard vertical length of the metal sheet, MS av is the measured vertical length of the metal sheet, MS ad is the standard width of the metal sheet, MS ad )

[0100] In addition, when the metal sheet passes over the roller provided in the roll forming machine, the average pressure failure rate (P) of the roller is determined using the measured average pressure value and the pre-stored average pressure value. fp ) can be calculated according to [Mathematical Formula 3] below.

[0101] [Mathematical Formula 3]

[0102]

[0103] (Here, P s is the pre-stored average pressure value of the roller, P a ) refers to the average pressure value actually measured on the roller during metal sheet forming)

[0104] At this time, the above-mentioned stored average pressure value may refer to the average pressure value of the roller generated during normal operation corresponding to the roll forming of a metal sheet of the corresponding dimensions and material stored in the roll forming machine.

[0105] In addition, the welding quality defect rate (W) is calculated using image data collected from the welding camera and thermal imaging camera provided in the welding step (140). fp ) can be calculated according to [Mathematical Formula 4].

[0106] [Mathematical Formula 4]

[0107]

[0108] (Here, WIP wa is the total number of pixels of the roll-formed steel pipe to be welded, WIP fwa represents the number of pixels in the defective welding area)

[0109] More specifically, the above welding quality defect rate (W fp ) can calculate the number of pixels in the roll-forming steel pipe area within the captured image data using image processing software, image processing and computer vision technology, and calculate the percentage of pixels in the defective weld area where defective weld areas are identified.

[0110] Here, in order to distinguish between the roll-forming steel pipe area and the defective welding area that are the welding targets within the image data, after loading the image data, preprocessing such as noise removal, contrast enhancement, and edge detection can be performed, and then techniques such as edge detection, corner detection, and blob detection can be used.

[0111] At this time, when distinguishing defective welding areas within the image data, the image data is divided to separate the roll-formed steel pipe, which is the welding target object, from the defective welding area, and a classification algorithm is further used to identify the defective welding area.

[0112] Meanwhile, the above classification algorithm uses a segmentation algorithm, and machine learning and deep learning technologies are used for classification, and a CNN (Convolutional Neural Network) can be used as a representative example.

[0113] Here, a training dataset stored in advance is used to use the deep learning technology, wherein the training dataset consists of roll forming steel pipe area image data and defective welding area image data input by an administrator, and through model training, testing, and verification using this, the performance of the deep learning technology can be continuously improved to enhance accuracy.

[0114] Meanwhile, to identify defective weld areas in the above image data, a clustering technique that identifies defective weld areas by grouping pixels or regions with similar characteristics may be further used.

[0115] In addition, to calculate the number of pixels in the roll-formed steel pipe area and defective welding area within the above image data, the number of pixels can be calculated using code that calculates the number of pixels in a specific area using Python and OpenCV.

[0116] For example, the code that uses the above Python and OpenCV to select a specific area using a specified top-left point (start point) and bottom-right point (end point) and calculates pixels in that area is represented as 'image = cv2.imread('image.jpg')', 'x1, y1 = 100, 100', 'x2, y2 = 200, 200', 'selected_area = iamage[y1:y2, x1:x2]', 'pixel_count = selected_area.shape[0] * selected_area.shape[1]', 'printf("Number of pixels in the selected area:", pixel_count)', where '100, 100' can mean the top-left point and '200, 200' can mean the bottom-right point.

[0117] In addition, the forming time variation rate (FT) is determined by utilizing the difference between the actual forming time from when the metal sheet fed into the roll forming machine is formed into a roll forming steel pipe and the pre-stored forming time, which is the normal forming time when forming a metal sheet of the same material and dimensions.fp ) can be calculated according to [Mathematical Formula 5].

[0118] [Mathematical Formula 5]

[0119]

[0120] (Here, FT s is the pre-stored forming time, FT a ) refers to the measured forming time)

[0121] Through this process, the judgment step (160) is the overall defective score (SF score ) can be produced.

[0122] For example, if the material of the metal sheet selected and cut in the metal sheet supply step (110) and the metal sheet cutting step (120) is steel, and the roll-formed steel pipe selected by the manager is a door frame, and the metal sheet fed during forming according to normal operation stored in the roll-forming machine for forming the door frame has a width of 100mm, a height of 100mm, and a depth of 20mm, an average roller pressure of 70MPa, and a forming time of 3 hours, and during actual forming, the metal sheet collected in the forming data and the judgment step (160) has a width of 99mm, a height of 101mm, and a depth of 20mm, a measured average roller pressure of 71MPa, and a forming time of 3 hours and 10 minutes, and among the image data of the door frame collected in the welding step (150), the number of pixels of the door frame is 345 and the number of pixels judged as defective areas is 32, then the metal according to [Equation 2] Sheet Dimension Defect Rate (MS) fp ) is approximately 0.006((|100-99| / 100+|100-101| / 100+|20-20| / 20) / 3), the average pressure failure rate of the roller according to [Equation 3] above (P fp ) is approximately 0.014 (|70-71| / 70), the welding quality defect rate (W according to the above [Equation 4]) fp) is approximately 0.092 (32 / 345), and the forming time variation rate (FT) according to the above [Equation 5] fp ) is calculated as approximately 0.055 (|180-190| / 180), and through this, the overall defective score (SF score ) can be calculated as 4.175 (25*(0.006+0.014+0.092+0.055)) according to the above [Mathematical Formula 1]. At this time, the total defect score (SF) that is judged as defective in the judgment step (160) is score If ) is set to 5 or higher, the door frame can be judged to be a good product.

[0123] Through the process described above, the roll-forming steel pipe manufacturing method allows a manager to supply a metal sheet coil of a specific material, uncoil it into a metal sheet, cut it to a predetermined size, and then transfer the cut metal sheet to a roll-forming machine to perform roll forming. Subsequently, automatic welding is performed using welding parameters corresponding to the material and welding area of ​​the formed roll-forming steel pipe, and surface processing, heat treatment, and coating can be performed after the welding process. In the post-processing stage, the overall defect score of the roll-forming steel pipe is calculated using the forming data collected during the post-processing and forming process, and a determination of defect or good quality is made based on whether it exceeds a standard value. Additionally, sensor fault diagnosis can be performed using sensing data collected from sensors installed in the roll-forming process.

[0124] According to one embodiment of the present invention, by manufacturing a door frame and a steel pipe using a roll forming machine, the time and cost required for the manufacturing process can be reduced.

[0125] In addition, by using data collected from sensors installed in the roll forming machine to diagnose whether a sensor is faulty, the failure rate can be reduced by rapidly diagnosing sensor failures.

[0126] In addition, by converting forming data collected from roll forming machines and defects collected from welding and surfaces into data to calculate a comprehensive defect score, it is possible to quickly identify whether a product is defective during the production process.

[0127] As described above, although an embodiment of the present invention has been explained by limited embodiments and drawings, the embodiment of the present invention is not limited to the embodiments described above, and various modifications and variations are possible from this description by those skilled in the art to which the present invention pertains. Accordingly, an embodiment of the present invention should be understood only by the claims described below, and all equivalent or analogous variations thereof shall be considered to be within the scope of the inventive concept. Explanation of the symbols

[0129] 100: Roll-formed steel pipe manufacturing method 110: Metal sheet supply step 120: Metal sheet cutting step 130: Forming stage 140: Welding step 150 : Post-processing step 151: Surface treatment step 152 : Heat treatment step 153: Coating Step 160: Judgment stage

Claims

Claim 1 A method for manufacturing a roll-formed steel pipe, characterized by comprising: a metal sheet supply step for supplying a metal sheet of a predetermined material; a metal sheet cutting step for cutting the metal sheet supplied in the metal sheet supply step into a predetermined size; a forming step for feeding the cut metal sheet into a roll-forming machine to manufacture it into a predetermined steel pipe shape; a welding step for welding the roll-formed steel pipe formed in the forming step; a post-processing step for performing post-processing on the inside and outside of the welded roll-formed steel pipe; and a determination step for determining the condition of the roll-forming machine and whether the post-processed roll-formed steel pipe is of good quality. Claim 2 A method for manufacturing a roll-formed steel pipe according to claim 1, wherein the forming step performs forming of a metal sheet fed using the roll forming machine, and collects forming data including the dimensions of the metal sheet fed, the pressure of the roller, the welding quality, and the forming time per metal sheet. Claim 3 A method for manufacturing a roll-formed steel pipe according to claim 1, wherein the welding step involves performing a welding process using an automatic welding device after fixing the roll-formed steel pipe, applying pre-set welding parameters corresponding to the shape and material of the roll-formed steel pipe, and monitoring the temperature of the welding area and the progress of the welding. Claim 4 A method for manufacturing a roll-formed steel pipe according to claim 1, wherein the post-processing step comprises: a surface treatment step for polishing the surface of the steel pipe welded in the welding step and removing welding dubbing; a heat treatment step for performing a heat treatment by heating the welded roll-formed steel pipe to a preset temperature; and a coating step for performing a coating on the surface of the welded steel pipe. Claim 5 In claim 1, the judgment step comprises a comprehensive defect score (SF) according to the following [Mathematical Formula 1] using the forming data. score Calculate ) and [Mathematical Formula 1] (Here, MS fp is the metal sheet dimensional defect rate, P fp is the average pressure failure rate of the roller, W fp is the welding quality defect rate, FT fp A method for manufacturing roll-formed steel pipes characterized by determining a defect when the above-mentioned total defect score exceeds a preset range (meaning the rate of variation in forming time).

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