A method for preparing a gas-shielded flux-cored wire

Abstract

The present application relates to the technical field of welding wire, and particularly relates to a preparation method of gas shielded flux cored wire, which comprises determining a hardening risk interval, setting a plurality of detection points on the edge of the steel strip in the hardening risk interval; using a roller to roll the steel strip into a continuous U-shaped groove; transmitting the flux powder of a preset temperature into the U-shaped groove to generate an initial welding wire; collecting the temperature change curve of each detection point; determining the defect length ratio of each hardening risk interval, determining whether to stop and perform closed detection on the initial welding wire based on the defect length ratio; determining whether to repair the initial welding wire of the corresponding hardening risk interval or cut off the initial welding wire of the corresponding hardening risk interval and adjust the rolling deviation threshold interval based on the powder leakage length ratio; and performing drawing and reducing the diameter of the qualified initial welding wire and the initial welding wire after repair to generate a finished product welding wire. The present application improves the quality stability of the preparation of the gas shielded flux cored wire by detecting the problem risk area and optimizing the parameters in the preparation process.

Description

Technical Field

[0001] This invention relates to the field of welding wire technology, and in particular to a method for preparing a gas-shielded flux-cored welding wire. Background Technology

[0002] Flux-cored welding wire is a high-performance welding material made by wrapping specific flux powder inside a thin steel strip, rolling it into a tube, and then reducing its diameter or drawing it. Its manufacturing process involves rolling the steel strip into a U-shaped cross-section, adding welding powder according to the dosage ratio, rolling it tightly, and then drawing it into products of different specifications. This unique steel-coated flux structure gives it both the efficiency of solid welding wire and the metallurgical control function of shielded metal arc welding (SMAW). The quality of the steel strip directly affects the entire process of the welding wire from forming and drawing to welding application, and is one of the core factors determining the stability of the welding wire's quality.

[0003] Chinese Patent Publication No. CN118438082A discloses a high-toughness wear-resistant flux-cored wire and its preparation method. This invention relates to the field of flux-cored wire technology, specifically disclosing a high-toughness wear-resistant flux-cored wire and its preparation method. The method includes the following steps: (1) uniformly mixing, grinding, and baking powder to obtain flux powder; (2) combing and cold bending steel strip to form a U-shaped tube with grooves; (3) adding flux powder into the grooves of the U-shaped tube, rolling it into an O-shaped tube, and drawing it multiple times to obtain a basic flux-cored wire; (4) coating the surface of the basic flux-cored wire to obtain a high-toughness wear-resistant flux-cored wire.

[0004] Therefore, the existing technology has the following problems: it does not consider the impact of the steel strip quality on the quality of U-groove closure during the preparation of flux-cored welding wire. Summary of the Invention

[0005] Therefore, the present invention provides a method for preparing gas-shielded flux-cored welding wire to overcome the problem in the prior art that the influence of steel strip quality on the quality of U-groove closure during the preparation of flux-cored welding wire is not considered.

[0006] To achieve the above objectives, the present invention provides a method for preparing a gas-shielded flux-cored welding wire, comprising: The steel strip is divided into several filling intervals with a preset length. Based on several steel strip images of each filling interval, a steel strip characterization coefficient is calculated to determine the hardening risk interval. Several detection points are set on the edge of the steel strip in the hardening risk interval. The steel strip is rolled into a continuous U-shaped groove using a rolling mill. The edge thickness and opening width of the steel strip at each detection point are obtained to generate a rolling deviation value. The closing treatment method of the U-shaped groove corresponding to the hardening risk range is determined by combining the preset rolling deviation threshold range. The powder at a preset temperature is transferred into the U-shaped groove, and the U-shaped groove is closed using the corresponding closing method to generate the initial welding wire; Temperature change curves at each detection point are collected, and the maximum temperature rise slope and highest temperature in each temperature change curve are calculated to generate closure feature values. Based on the closure feature values, it is determined whether the closure quality of each detection point is qualified. The non-conforming detection points in each hardening risk zone are summarized to determine the defect length ratio of each hardening risk zone. Based on the defect length ratio, it is determined whether to stop the machine to perform a closure test on the initial welding wire. In response to the closure detection, the detection point where powder leakage occurs is determined based on the initial welding wire image to generate a powder leakage length ratio. Based on the powder leakage length ratio, it is determined whether to repair the initial welding wire in the corresponding hardening risk zone or to cut off the initial welding wire in the corresponding hardening risk zone and adjust the rolling deviation threshold range. The qualified initial welding wire and the repaired initial welding wire are drawn and reduced in diameter to produce finished welding wire.

[0007] Furthermore, the process of determining the steel strip characterization coefficient for each filling interval includes, Analyze steel strip images to classify steel strip burrs into brittle burrs and ductile burrs; The total number of burrs is the sum of the number of brittle burrs and the number of ductile burrs. The ratio of the number of brittle burrs to the total number of burrs is determined as the steel strip characterization coefficient.

[0008] Furthermore, the process of determining the hardening risk zone includes, If the steel strip characterization coefficient of the filling interval is greater than or equal to the preset steel strip characterization coefficient threshold, then the filling interval is determined to be a hardening risk interval.

[0009] Furthermore, the process of setting up several detection points on the edge of the steel strip in the hardened risk zone includes, Calculate the ratio of the steel strip characterization coefficient threshold to the steel strip characterization coefficient for each hardening risk interval; The product of each of the characterization coefficient ratios and the initial spacing is used to determine the spacing of the detection points in the corresponding hardening risk zone. Starting from the endpoint of the hardening risk zone entering the roll, several detection points are sequentially set along the steel strip travel direction at the specified spacing. The steel strip edge is a U-shaped groove with an upright sidewall.

[0010] Furthermore, the process of generating rolling deviation values ​​includes, The ratio of the edge thickness of the steel strip to the edge thickness of the standard steel strip is determined as the thickness influence factor; The ratio of the opening width value to the standard opening width value is determined as the width influence factor; The weighted sum of the thickness influence factor and the width influence factor is determined to be the rolling deviation value.

[0011] Furthermore, the process of determining the closure method of the U-shaped groove corresponding to the hardening risk interval includes, If the rolling deviation value is less than or equal to the minimum value of the rolling deviation threshold range, then the closing treatment method of the U-groove corresponding to the hardening risk range is determined to be a single bend with preset bending parameters. If the rolling deviation value is within the rolling deviation threshold range, then the closing treatment method of the U-groove corresponding to the hardening risk range is to adjust the preset bending parameters to perform a single bend. If the rolling deviation value is greater than or equal to the maximum value of the rolling deviation threshold range, then the closing treatment method for the U-shaped groove corresponding to the hardening risk range is to adjust the preset bending parameters and increase the number of bends. The preset bending parameters include preset bending angle and preset overlap amount.

[0012] Furthermore, the process of generating closed eigenvalues ​​includes, Calculate several temperature rise slopes in the generated temperature change curve to filter out the maximum temperature rise slope and determine the highest temperature in the temperature change curve. The ratio of the maximum heating slope to the standard maximum heating slope is determined as the slope influence factor; The ratio of the highest temperature to the standard highest temperature is determined as the temperature influence factor; The weighted sum of the slope influence factor and the temperature influence factor is determined to be a closed eigenvalue.

[0013] Furthermore, the process of determining whether the closure quality of each detection point is qualified based on the closure feature value includes, If the closure feature value is less than or equal to the feature value threshold, the closure quality of the detection point is determined to be unqualified.

[0014] Furthermore, the process of determining whether to stop the machine and perform closure detection on the initial welding wire based on the defect length ratio includes, The ratio of the length between the farthest non-conforming test points within the hardening risk range to a preset length is defined as the defect length ratio. If the defect length ratio is less than a preset defect length ratio threshold, the system will not stop. In response to the defect length ratio being greater than or equal to the preset defect length ratio threshold, the machine is stopped to perform a closure detection on the initial welding wire.

[0015] Furthermore, the process of determining the initial welding wire for repairing the corresponding hardening risk zone or cutting off the initial welding wire for the corresponding hardening risk zone and adjusting the rolling deviation threshold zone based on the powder leakage length ratio includes, In response to the closure detection, the initial welding wire images of each detection point contained in the initial welding wire of the hardening risk zone are acquired and analyzed to determine the detection point where powder leakage occurs. The ratio of the distance between the farthest detection points where powder leakage occurs within the hardening risk range to the distance between the farthest non-conforming detection points within the hardening risk range is called the powder leakage length ratio. In response to the fact that the powder leakage length ratio is less than a preset powder leakage length ratio threshold, the initial welding wire corresponding to the hardening risk range is determined to be repaired; In response to the powder leakage length ratio being greater than or equal to the preset powder leakage length ratio threshold, the initial welding wire in the corresponding hardening risk range is determined to be cut off and the rolling deviation threshold range is adjusted.

[0016] Compared with the prior art, the beneficial effects of this invention are as follows: In implementation, by dividing the steel strip into several filling intervals with a preset length, and performing characteristic parameter analysis on each filling interval to determine the hardening risk interval, several detection points are set on the edge of the steel strip in the hardening risk interval, providing a unified and fixed reference benchmark for quality inspection throughout the entire preparation process. By analyzing the finished product rolled in the U-groove, the closing treatment method of the U-groove corresponding to the hardening risk interval is determined. Differential and precise control of process parameters is achieved before welding wire forming, effectively reducing the forming difficulty caused by steel strip hardening, reducing the occurrence of defects such as incomplete closure of the U-groove sidewalls and poor forming, and significantly improving the initial forming qualification rate of the welding wire. The flux powder is preheated and transferred to the U-groove for sampling. The U-shaped groove is closed using the corresponding closure process to generate the initial welding wire. As the flux powder continuously releases heat in the initial welding wire, the closure quality of the two upright sidewall steel strips of the U-shaped groove corresponding to the initial welding wire is analyzed by collecting temperature changes at different detection points. When there is an air gap between the two upright sidewall steel strips of the U-shaped groove corresponding to the initial welding wire, the closure area corresponding to the air gap and the closure area corresponding to the qualified initial welding wire have slower heating and lower maximum temperature because the thermal conductivity of air is much lower than that of steel strips. This allows for quick and accurate identification of the problem area, reducing the false negative rate and improving the detection accuracy. Further detection of the problem area and optimization of the parameters in the preparation process improve the quality stability of the gas-shielded flux-cored welding wire preparation.

[0017] Furthermore, this invention analyzes the burr properties of the steel strip using images to obtain the ratio of brittle burrs to the total number of burrs. Because brittle burrs, unlike ductile burrs, cannot be flattened during steel strip rolling, they break off from the strip edge under immense rolling pressure. If these small, hard particles fall between the steel strip and the rolls, they will be pressed into the strip surface, forming localized pits or indentations. This damages the surface smoothness of the steel strip and hinders the precise alignment of the edges during U-groove closure. The presence of brittle burrs results in uneven edges, preventing the formation of a smooth, continuous seam. This can lead to irregular spiral shapes or localized openings at the forming interface, which complicates subsequent processing. This approach addresses potential risks by precisely differentiating the nature of burrs and quantifying the proportion of brittle burrs using steel strip images. This allows for accurate identification of core quality risk sources in welding wire preparation. Areas with potential risks are designated as hardening risk zones. Furthermore, the interval between detection points is adjusted based on the actual steel strip characterization coefficients for each hardening risk zone. The interval is dynamically adjusted according to the steel strip characterization coefficients of the hardening risk zones, with increased density of detection points in high-risk zones to ensure no core quality risks are overlooked. For low-risk zones, the detection density is optimized to avoid efficiency losses due to over-detection. This approach balances detection accuracy with the efficiency of continuous production, further improving the quality stability of gas-shielded flux-cored welding wire preparation.

[0018] Furthermore, this invention employs corresponding closure methods for U-shaped grooves in different states. These targeted closure methods can proactively avoid problems such as incomplete closure of the upper and lower steel strip edges during the U-shaped groove closure process, thus preventing forming defects caused by incomplete closure of the upper and lower steel strip edges and improving the forming accuracy and joint consistency of the welding wire blank. Simultaneously, by preheating the flux powder and loading the preheated powder into the U-shaped groove before performing the targeted closure process, the combined effect of preheating and targeted closure removes moisture from the flux powder, improves welding performance, and optimizes the uniformity of flux powder filling, further ensuring joint accuracy and eliminating performance fluctuations caused by uneven powder loading. By detecting the temperature changes at the detection points on the edges of the upper and lower steel strips after the initial closure, the quality of the closure at the edges of the upper and lower steel strips is checked to ensure the presence of gaps, improving the quality stability of the welding wire preparation and further enhancing the quality stability of gas-shielded flux-cored welding wire preparation.

[0019] Furthermore, this invention summarizes the non-conforming detection points within each hardening risk interval, determines the ratio of the length between the farthest non-conforming detection points within the hardening risk interval to a preset length as the defect length ratio, and determines the ratio of the length between the farthest powder leakage detection points within the hardening risk interval to the length between the farthest non-conforming detection points within the hardening risk interval as the powder leakage length ratio. Since gaps in the steel strip will form a gap band of a certain length, the degree of defect is characterized based on the length of the gap band. Based on whether serious quality problems such as powder leakage occur in the gap band, the method for repairing the initial welding wire of the corresponding hardening risk interval is determined, or the method for cutting off the initial welding wire of the corresponding hardening risk interval and adjusting the rolling deviation threshold interval is determined for the initial welding wire with serious powder leakage. By adjusting the rolling deviation threshold interval, a more suitable closure treatment method is adopted for subsequent steel strips under the same working conditions, so as to reduce the occurrence of quality problems such as incomplete closure in the future. The discrete single-point detection results are transformed into a precise quantitative characterization of continuous gap band defects. It not only clearly defines the actual impact length and range of defects, but also accurately distinguishes the severity levels of ordinary incomplete closure defects and fatal powder leakage defects, minimizing the loss of raw materials and semi-finished products, optimizing the closure treatment method of steel strip under the same working conditions, systematically reducing the recurrence rate of similar closure defects from the root of the process, and further improving the quality stability of gas-shielded flux-cored welding wire preparation. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation method of the gas-shielded flux-cored welding wire according to an embodiment of the present invention. Figure 2 This is the logic diagram for determining the hardening risk range in this embodiment; Figure 3 This embodiment defines the logic decision diagram for determining the closure method of the U-shaped groove corresponding to the hardening risk zone. Figure 4 This is a logic diagram for determining whether the closure quality of each detection point is qualified in this embodiment. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0024] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Example 1: Please see Figure 1 As shown, Figure 1 This is a flowchart illustrating the preparation method of the gas-shielded flux-cored welding wire according to an embodiment of the present invention. This invention provides a method for preparing a gas-shielded flux-cored welding wire, comprising: Step S1: Divide the steel strip into several filling intervals with a preset length, calculate and generate steel strip characterization coefficients based on several steel strip images of each filling interval to determine the hardening risk interval, and set several detection points on the edge of the steel strip in the hardening risk interval. Step S2: Use rolls to roll the steel strip into a continuous U-shaped groove, obtain the edge thickness value and opening width value of the steel strip at each detection point to generate rolling deviation value, and determine the closing treatment method of the U-shaped groove corresponding to the hardening risk range by combining the preset rolling deviation threshold range. Step S3: Transfer the powder at a preset temperature into the U-shaped groove, and close the U-shaped groove using the corresponding closing method to generate the initial welding wire; Step S4: Collect the temperature change curves of each detection point, calculate the maximum temperature rise slope and the highest temperature in each temperature change curve to generate a closure feature value, and determine whether the closure quality of each detection point is qualified based on the closure feature value. Step S5: Summarize the non-conforming detection points in each hardening risk zone to determine the defect length ratio of each hardening risk zone, and determine whether to stop the machine to perform a closure detection on the initial welding wire based on the defect length ratio. Step S6: In response to performing closure detection, the detection point where powder leakage occurs is determined based on the initial welding wire image to generate a powder leakage length ratio. Based on the powder leakage length ratio, it is determined whether to repair the initial welding wire in the corresponding hardening risk zone or cut off the initial welding wire in the corresponding hardening risk zone and adjust the rolling deviation threshold range. Step S7: The qualified initial welding wire and the repaired initial welding wire are drawn and reduced in diameter to produce finished welding wire.

[0026] Specifically, when acquiring images of the steel strip and the initial welding wire, a high-speed linear scan camera is used, optionally with a resolution ≥4K and a line frequency ≥20kHz. It is vertically mounted directly above the steel strip and performs a full-coverage scan along the width of the steel strip to achieve uninterrupted longitudinal imaging. At the same time, dual auxiliary linear scan cameras are used, optionally with a resolution ≥2K and a line frequency ≥10kHz. They are tilted at 45° and mounted on the left and right sides of the steel strip to acquire the three-dimensional contours and burr morphology of the edges, eliminating the detection blind spots of the frontal view. This will not be elaborated further here.

[0027] Specifically, when obtaining the steel strip edge thickness and opening width values ​​at each detection point, an industrial camera can be used to acquire cross-sectional images of the U-shaped groove. These images are then denoised and enhanced. The Canny edge detection algorithm or the Sobel operator is applied to identify the vertical edges on both sides of the steel strip in the image. Based on pixel-level measurements, grayscale gradient fitting is used to locate the edges to the sub-pixel level. The horizontal pixel distance between the left and right edges in the image is calculated and then converted to the actual opening width using a calibrated pixel equivalent, such as mm / pixel. Through image processing, the outer and inner contour lines of the entire U-shaped groove cross-section are extracted. Points on the outer and inner contour lines are extracted respectively, and the vertical distance between these two lines is calculated. This distance represents the steel strip thickness at that point, which will not be elaborated further here.

[0028] Specifically, when preheating the powder, a heating device such as a continuous ribbon preheating device can be used to directly feed the preheated powder into a heat-traced and insulated discharge buffer bin. The bottom of the buffer bin is sealed and connected to the U-shaped groove screw filling machine. The preheated powder is directly and continuously filled into the moving U-shaped groove by a metering screw. The time from powder discharge to filling is controlled within 10 seconds to reduce the temperature loss of the powder filling into the U-shaped groove. Optionally, the preset temperature range is [180℃, 320℃]. Preferably, in this embodiment, 260℃ is used.

[0029] Specifically, when collecting temperature change curves at each detection point, the temperature data corresponds to the detection point. The infrared thermal radiation of the initial welding wire is captured by an area array infrared thermal imager, and temperature field data of the entire field of view is continuously collected. Combined with a high-precision encoder on the welding wire traction wheel, precise synchronization of temperature data and welding wire length position is achieved.

[0030] Specifically, closure detection addresses the issue of determining whether powder leakage has occurred at a detection point based on an initial weld wire image. For those skilled in the art, analyzing the initial weld wire image to determine the detection point where powder leakage has occurred is existing technology and will not be elaborated upon here.

[0031] Specifically, the initial welding wire for repairing the corresponding hardening risk zone can be repaired by slightly increasing the reduction of the closed roll to allow the edge to fit more closely. Optionally, the increment range is [0.05mm, 0.1mm], which will not be elaborated here.

[0032] Specifically, when cutting off the initial welding wire in the corresponding hardening risk zone, find the starting and ending positions of the powder leakage, cut off the entire section, and connect the end of the initial welding wire in the front section with the end of the initial welding wire in the back section. The connection method can be resistance welding using a welding machine.

[0033] In this embodiment of the invention, taking the titanium-type (rutile-type) gas-shielded flux-cored wire, which is used most extensively in industries such as shipbuilding, bridges, and steel structures for welding ordinary carbon steel and low alloy steel, as an example, the steel strip is selected as a low carbon steel strip with an initial thickness of 1 mm and an initial width of 7 mm.

[0034] Medicine powder: Prepare the following ingredients by weight. Slag-forming agent: rutile: 45 parts, quartz: 5 parts, zircon sand: 8 parts, feldspar: 8 parts; Alloying agent: ferromanganese / silicon-manganese alloy: 20 parts; iron powder: 30 parts; Deoxidizer, aluminum powder / aluminum-magnesium powder: 2.5 parts; Arc stabilizer: potassium titanate: 5 parts, potassium feldspar: 8 parts, sodium feldspar: 8 parts.

[0035] It is understood that the "powder" refers to a complex mixture, typically composed of slag-forming agents, alloying agents, arc-stabilizing agents, and deoxidizers. The formulation of the flux core is determined by the final performance of the welding wire, such as strength, toughness, wear resistance, and welding processability. In step S3, the flux powder is directly used for preheating.

[0036] Specifically, in implementation, the steel strip is divided into several filling sections according to a preset length. Characteristic parameter analysis is performed on each filling section to determine the hardening risk zone. Several detection points are set on the edge of the steel strip in the hardening risk zone, providing a unified and fixed reference standard for quality inspection throughout the entire preparation process. Analysis of the finished U-groove rolled product determines the closure treatment method for the U-groove corresponding to the hardening risk zone. Differential and precise control of process parameters is achieved before welding wire forming, effectively reducing the forming difficulty caused by steel strip hardening, reducing defects such as incomplete closure of the U-groove sidewalls and poor forming, and significantly improving the initial forming pass rate of the welding wire. The flux powder is preheated and transferred to the U-groove for corresponding closure treatment. The method involves closing a U-shaped groove to generate the initial welding wire. As the flux powder continuously releases heat within the initial welding wire, the closure quality of the two upright steel strips on the U-shaped groove corresponding to the initial welding wire is analyzed by collecting temperature changes at different detection points. When an air gap exists between the two upright steel strips on the U-shaped groove corresponding to the initial welding wire, the temperature rise of the closed area corresponding to the air gap is slower and the maximum temperature is lower than that of the closed area corresponding to the qualified initial welding wire because air has a much lower thermal conductivity than steel. This allows for quick and accurate identification of problem areas, reducing the false negative rate and improving detection accuracy. Further detection of problem areas and optimization of parameters in the preparation process improve the quality stability of gas-shielded flux-cored welding wire preparation.

[0037] Specifically, in step S1, the process of determining the steel strip characterization coefficient for each filling interval includes, Analyze steel strip images to classify steel strip burrs into brittle burrs and ductile burrs; The total number of burrs is the sum of the number of brittle burrs and the number of ductile burrs. The ratio of the number of brittle burrs to the total number of burrs is determined as the steel strip characterization coefficient.

[0038] Specifically, burrs with an aspect ratio greater than or equal to the aspect ratio threshold are classified as brittle burrs; burrs with an aspect ratio less than the aspect ratio threshold are classified as plastic burrs.

[0039] Specifically, the purpose of setting the aspect ratio threshold is to characterize the plasticity of the burr. The larger the aspect ratio, the more brittle the burr, and the higher the accuracy requirement for detection. The smaller the aspect ratio threshold, the better. The aspect ratio threshold can be set in the range of [1 / 3, 1]. Preferably, burrs with an aspect ratio less than 1 / 2 are considered plastic burrs, and burrs with an aspect ratio greater than or equal to 1 / 2 are considered brittle burrs.

[0040] Please see Figure 2 As shown, this is a logic decision diagram for determining the hardening risk interval in this embodiment. In step S1, the process of determining the hardening risk interval includes: If the steel strip characterization coefficient of the filling interval is less than the preset steel strip characterization coefficient threshold, the filling interval is determined to be a non-hardening risk interval. If the steel strip characterization coefficient of the filling interval is greater than or equal to the preset steel strip characterization coefficient threshold, the filling interval is determined to be a hardening risk interval.

[0041] Specifically, the purpose of setting the steel strip characterization coefficient threshold is to characterize the proportion of brittle burrs in the total number of burrs within a single hardening risk interval. The higher the detection accuracy requirement, the smaller the steel strip characterization coefficient threshold should be. The value range of the steel strip characterization coefficient threshold can be [0.2, 0.5]. Preferably, the steel strip characterization coefficient threshold can be 0.3.

[0042] Specifically, in step S1, the process of setting several detection points on the edge of the steel strip in the hardened risk zone includes, Calculate the ratio of the steel strip characterization coefficient threshold to the steel strip characterization coefficient for each hardening risk interval; The product of each characterization coefficient ratio and the initial spacing is used to determine the spacing of the detection points in the corresponding hardening risk zone. Starting from the end point of the hardened risk zone entering the roll, several inspection points are set sequentially along the direction of steel strip travel at intervals. The steel strip edge has a U-shaped groove with upright sidewalls.

[0043] It is understandable that the starting point of the hardened risk zone entering the roll is taken as the starting point of the inspection, and the ending point of the hardened risk zone entering the roll is taken as the final inspection point. Several inspection points are set sequentially along the direction of the steel strip travel at a certain spacing, and the distance between each adjacent inspection point is less than the spacing.

[0044] Specifically, this invention analyzes the burr properties of steel strip through steel strip images to obtain the ratio of brittle burrs to the total number of burrs. Because brittle burrs, unlike ductile burrs, cannot be flattened during steel strip rolling, they break off from the strip edge under immense rolling pressure. If these detached fine, hard particles fall between the steel strip and the rolls, they will be pressed into the strip surface, forming localized pits or indentations. This disrupts the surface smoothness of the steel strip and hinders the precise alignment of the edges during U-groove closure. The presence of brittle burrs results in uneven edges, preventing the formation of a smooth, continuous seam. This can lead to irregular spiral shapes or localized openings at the forming interface, which complicates subsequent processing. This approach addresses potential risks by precisely differentiating the nature of burrs and quantifying the proportion of brittle burrs using steel strip images. This allows for accurate identification of core quality risk sources in welding wire preparation. Areas with potential risks are designated as hardening risk zones. Furthermore, the interval between detection points is adjusted based on the actual steel strip characterization coefficients for each hardening risk zone. The interval is dynamically adjusted according to the steel strip characterization coefficients of the hardening risk zones, with increased density of detection points in high-risk zones to ensure no core quality risks are overlooked. For low-risk zones, the detection density is optimized to avoid efficiency losses due to over-detection. This approach balances detection accuracy with the efficiency of continuous production, further improving the quality stability of gas-shielded flux-cored welding wire preparation.

[0045] Specifically, in step S2, the process of generating the rolling deviation value includes, The ratio of the edge thickness of the steel strip to the edge thickness of the standard steel strip is determined as the thickness influence factor; The ratio of the opening width value to the standard opening width value is determined as the width influence factor; The weighted sum of the thickness influence factor and the width influence factor is determined to be the rolling deviation value.

[0046] Specifically, in practice, the standard steel strip edge thickness value is the average value of the steel strip edge thickness of U-shaped grooves of the same material under the same working conditions, and the standard opening width value is the average value of the opening width of U-shaped grooves of the same material under the same working conditions.

[0047] Specifically, the sum of the weighting coefficients of the thickness influence factor and the width influence factor is 1. Since the thickness influence factor and the width influence factor have roughly the same characterization of the U-groove rolling deviation, preferably, the weighting coefficient of the thickness influence factor is 0.5 and the weighting coefficient of the width influence factor is 0.5.

[0048] Please see Figure 3 As shown, this is a logic decision diagram for determining the closure method of the U-shaped groove corresponding to the hardening risk range in this embodiment. In step S2, the process of determining the closure method of the U-shaped groove corresponding to the hardening risk range includes, If the rolling deviation value is less than or equal to the minimum value of the rolling deviation threshold range, then the closing treatment method of the U-groove corresponding to the hardening risk range is to perform a single bend with preset bending parameters. If the rolling deviation value is within the rolling deviation threshold range, the closing treatment method for the U-groove corresponding to the hardening risk range is to adjust the preset bending parameters to perform a single bend. If the rolling deviation value is greater than or equal to the maximum value of the rolling deviation threshold range, the closing treatment method for the U-shaped groove corresponding to the hardening risk range is to adjust the preset bending parameters and increase the number of bends. Specifically, the purpose of setting the rolling deviation threshold range is to characterize the consistency of the opening width and edge thickness of the U-groove generated by rolling a steel strip with hardening risk with that generated by rolling a steel strip of the same specification under the same working conditions. The minimum value of the rolling deviation threshold range is selected within the range [1.0, 1.05], and the maximum value of the rolling deviation threshold range is selected within the range [1.1, 1.15]. Preferably, the minimum value of the rolling deviation threshold range is 1.03, and the maximum value of the rolling deviation threshold range is 1.12.

[0049] Understandably, under the same working conditions, steel strips with hardening issues will have a greater springback and thickness when rolled into U-grooves than normal steel strips.

[0050] The preset bending parameters include the preset bending angle and the preset overlap amount.

[0051] Specifically, in this embodiment, the preset bending angle is set to 90° and the preset overlap is set to 1mm. If the rolling deviation value is less than or equal to the minimum value of the rolling deviation threshold range, the closing treatment method of the U-shaped groove corresponding to the hardening risk range is determined to be a single bend with a preset bending angle of 90° and a preset overlap of 1mm. If the rolling deviation value is within the rolling deviation threshold range, the closing treatment method for the U-shaped groove corresponding to the hardening risk range is to adjust the preset bending angle to 92° and the preset overlap amount to 1.2mm for a single bend. If the rolling deviation value is greater than or equal to the maximum value of the rolling deviation threshold range, the closing treatment method for the U-shaped groove corresponding to the hardening risk range is to adjust the preset bending angle to 95°, adjust the preset overlap amount to 1.2mm, and perform double bending.

[0052] Specifically, in step S4, the process of generating closed eigenvalues ​​includes, Calculate several temperature rise slopes in the generated temperature change curve to screen out the maximum temperature rise slope and determine the highest temperature in the temperature change curve. The ratio of the maximum heating slope to the standard maximum heating slope is determined as the slope influence factor; The ratio of the highest temperature to the standard highest temperature is determined as the temperature influence factor; The weighted sum of the slope influence factor and the temperature influence factor is determined to be a closed eigenvalue.

[0053] Specifically, in implementation, the standard maximum temperature rise slope is the average of the maximum temperature rise slopes of the initial welding wires generated from several steel strips of the same specification and material without hardening problems under the same working conditions, and the standard maximum temperature is the average of the maximum temperatures of the initial welding wires generated from several steel strips of the same specification and material without hardening problems under the same working conditions.

[0054] Specifically, the sum of the weighting coefficients of the slope influence factor and the temperature influence factor is 1. Since the heating rate more accurately represents the voids, preferably, the weighting coefficient of the slope influence factor is 0.6 and the weighting coefficient of the temperature influence factor is 0.4.

[0055] It is understandable that constructing a temperature change curve with time as the horizontal axis and temperature as the vertical axis is a technique that those skilled in the art can use to calculate the maximum temperature rise slope and the highest temperature, and will not be elaborated here.

[0056] Please see Figure 4 As shown, this is a logic diagram for determining whether the closure quality of each detection point is qualified in this embodiment. In step S4, the process of determining whether the closure quality of each detection point is qualified based on the closure feature value includes: If the closure feature value is greater than the feature value threshold, the closure quality of the detection point is determined to be qualified. If the closure feature value is less than or equal to the feature value threshold, the closure quality of the detection point is determined to be unqualified.

[0057] Specifically, the purpose of setting the feature value threshold is to characterize the consistency between the maximum heating slope and the maximum temperature at the detection point on the initial welding wire with hardening risk and the maximum heating slope and the maximum temperature of the initial welding wire of the same specification without hardening risk under the same working conditions. The feature value threshold is selected in the range [0.85, 0.95], and preferably, the feature value threshold is 0.9.

[0058] Specifically, this invention employs corresponding closure methods for U-shaped grooves in different states. These targeted closure methods can proactively avoid problems such as incomplete closure of the upper and lower steel strip edges during the U-shaped groove closure process, thus preventing forming defects caused by incomplete closure of the upper and lower steel strip edges and improving the forming accuracy and joint consistency of the welding wire blank. Simultaneously, by preheating the flux powder and loading the preheated powder into the U-shaped groove before performing the targeted closure process, the combined effect of preheating and targeted closure removes moisture from the flux powder, improves welding performance, optimizes the uniformity of flux powder filling, further ensures joint accuracy, and eliminates performance fluctuations caused by uneven powder loading. By detecting the temperature changes at the detection points on the edges of the upper and lower steel strips after the initial closure, the quality of the closure at the edges of the upper and lower steel strips is checked to ensure the presence of gaps, improving the quality stability of the welding wire preparation and further enhancing the quality stability of gas-shielded flux-cored welding wire preparation.

[0059] Specifically, in step S5, the process of determining whether to stop the machine and performing a closure detection on the initial welding wire based on the defect length ratio includes: The ratio of the length between the farthest non-conforming test points within the hardening risk zone to the preset length is defined as the defect length ratio. If the defect length ratio is less than a preset defect length ratio threshold, the system will not stop. In response to a defect length ratio greater than or equal to a preset defect length ratio threshold, the machine is stopped to perform a closure detection on the initial welding wire.

[0060] Specifically, the preset defect length ratio threshold is the product of the defect length ratio reference value and the defect length ratio factor. The defect length ratio reference value is the average defect length ratio of the initial welding wires without hardening risk under the same working conditions in historical data. The defect length ratio factor can be set by those skilled in the art according to the accuracy requirements of hardening risk detection. The higher the accuracy requirement, the smaller the value should be. The value range can be [1.1, 1.3], preferably 1.2.

[0061] Specifically, in step S6, the process of determining the initial welding wire for repairing the corresponding hardening risk zone or cutting off the initial welding wire for the corresponding hardening risk zone and adjusting the rolling deviation threshold zone based on the powder leakage length ratio includes, In response to the closure detection, the initial welding wire images of each detection point contained in the initial welding wire of the hardening risk zone are acquired and analyzed to determine the detection point where powder leakage occurs. The ratio of the distance between the farthest detection points where powder leakage occurs within the hardening risk range to the distance between the farthest non-conforming detection points within the hardening risk range is called the powder leakage length ratio. In response to a powder leakage length ratio being less than a preset powder leakage length ratio threshold, the initial welding wire corresponding to the hardening risk zone is determined for repair. In response to a powder leakage length ratio greater than or equal to a preset powder leakage length ratio threshold, the initial welding wire in the corresponding hardening risk zone is removed and the rolling deviation threshold range is adjusted.

[0062] Specifically, the preset powder leakage length ratio threshold is the product of the powder leakage length ratio reference value and the powder leakage length ratio factor. The powder leakage length ratio reference value is the average powder leakage length ratio of the initial welding wires with the same defect length ratio under the same working conditions in historical data. The powder leakage length ratio factor can be set by those skilled in the art according to the accuracy requirements of hardening risk detection. The higher the accuracy requirement, the smaller the value should be. The value range can be [1.0, 1.3], preferably 1.1.

[0063] Understandably, in the process of determining the reference value of the powder leakage length ratio, if there is no initial welding wire with the same defect length ratio under the same working conditions in the historical data, the average value of the powder leakage length ratio of the initial welding wire with the closest defect length ratio is selected as the reference value of the powder leakage length ratio, and the powder leakage length ratio of the initial welding wire with the current defect length ratio is stored as historical data.

[0064] Specifically, this invention summarizes the non-conforming detection points within each hardening risk zone, determines the defect length ratio by comparing the length between the farthest non-conforming detection points within the hardening risk zone with a preset length, and determines the powder leakage length ratio by comparing the length between the farthest powder leakage detection points within the hardening risk zone with the length between the farthest non-conforming detection points within the hardening risk zone. Since gaps in the steel strip will form a gap band of a certain length, the length of the gap band is used to characterize the degree of defect. Based on whether serious quality problems such as powder leakage occur in the gap band, the method for repairing the initial welding wire of the corresponding hardening risk zone is determined, or the method for cutting off the initial welding wire of the corresponding hardening risk zone and adjusting the rolling deviation threshold range is used for the initial welding wire with serious powder leakage. By adjusting the rolling deviation threshold range, a more suitable closure treatment method is adopted for subsequent steel strips under the same working conditions, so as to reduce subsequent quality problems such as incomplete closure. The discrete single-point detection results are transformed into a precise quantitative characterization of continuous gap band defects. It not only clearly defines the actual impact length and range of defects, but also accurately distinguishes the severity levels of ordinary incomplete closure defects and fatal powder leakage defects, minimizing the loss of raw materials and semi-finished products, optimizing the closure treatment method of steel strip under the same working conditions, systematically reducing the recurrence rate of similar closure defects from the root of the process, and further improving the quality stability of gas-shielded flux-cored welding wire preparation.

[0065] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a gas-shielded flux-cored welding wire, characterized in that, include: The steel strip is divided into several filling intervals with a preset length. Based on several steel strip images of each filling interval, a steel strip characterization coefficient is calculated to determine the hardening risk interval. Several detection points are set on the edge of the steel strip in the hardening risk interval. The steel strip is rolled into a continuous U-shaped groove using a rolling mill. The edge thickness and opening width of the steel strip at each detection point are obtained to generate a rolling deviation value. The closing treatment method of the U-shaped groove corresponding to the hardening risk range is determined by combining the preset rolling deviation threshold range. The powder at a preset temperature is transferred into the U-shaped groove, and the U-shaped groove is closed using the corresponding closing method to generate the initial welding wire; Temperature change curves at each detection point are collected, and the maximum temperature rise slope and highest temperature in each temperature change curve are calculated to generate closure feature values. Based on the closure feature values, it is determined whether the closure quality of each detection point is qualified. The non-conforming detection points in each hardening risk zone are summarized to determine the defect length ratio of each hardening risk zone. Based on the defect length ratio, it is determined whether to stop the machine to perform a closure detection on the initial welding wire. In response to the closure detection, the detection point where powder leakage occurs is determined based on the initial welding wire image to generate a powder leakage length ratio. Based on the powder leakage length ratio, it is determined whether to repair the initial welding wire in the corresponding hardening risk zone or to cut off the initial welding wire in the corresponding hardening risk zone and adjust the rolling deviation threshold range. The qualified initial welding wire and the repaired initial welding wire are drawn and reduced in diameter to produce finished welding wire; The process of determining the steel strip characterization coefficient for each filling interval includes, Analyze steel strip images to classify steel strip burrs into brittle burrs and ductile burrs; The total number of burrs is the sum of the number of brittle burrs and the number of ductile burrs. The ratio of the number of brittle burrs to the total number of burrs is determined as the steel strip characterization coefficient.

2. The method for preparing gas-shielded flux-cored welding wire according to claim 1, characterized in that, The process of determining the hardening risk zone includes, If the steel strip characterization coefficient of the filling interval is greater than or equal to the preset steel strip characterization coefficient threshold, then the filling interval is determined to be a hardening risk interval.

3. The method for preparing gas-shielded flux-cored welding wire according to claim 2, characterized in that, The process of setting up several detection points on the edge of the steel strip in the hardening risk zone includes, Calculate the ratio of the steel strip characterization coefficient threshold to the steel strip characterization coefficient for each hardening risk interval; The product of each of the characterization coefficient ratios and the initial spacing is used to determine the spacing of the detection points in the corresponding hardening risk zone. Starting from the endpoint of the hardening risk zone entering the roll, several detection points are sequentially set along the steel strip travel direction at the specified spacing. The steel strip edge is a U-shaped groove with an upright sidewall.

4. The method for preparing gas-shielded flux-cored welding wire according to claim 3, characterized in that, The process of generating rolling deviation values ​​includes, The ratio of the edge thickness of the steel strip to the edge thickness of the standard steel strip is determined as the thickness influence factor; The ratio of the opening width value to the standard opening width value is determined as the width influence factor; The weighted sum of the thickness influence factor and the width influence factor is determined to be the rolling deviation value.

5. The method for preparing gas-shielded flux-cored welding wire according to claim 4, characterized in that, The process of determining the closure method of the U-shaped groove corresponding to the hardening risk range includes, If the rolling deviation value is less than or equal to the minimum value of the rolling deviation threshold range, then the closing treatment method of the U-groove corresponding to the hardening risk range is determined to be a single bend with preset bending parameters. If the rolling deviation value is within the rolling deviation threshold range, then the closing treatment method of the U-groove corresponding to the hardening risk range is to adjust the preset bending parameters to perform a single bend. If the rolling deviation value is greater than or equal to the maximum value of the rolling deviation threshold range, then the closing treatment method for the U-shaped groove corresponding to the hardening risk range is to adjust the preset bending parameters and increase the number of bends. The preset bending parameters include preset bending angle and preset overlap amount.

6. The method for preparing gas-shielded flux-cored welding wire according to claim 5, characterized in that, The process of generating closed eigenvalues ​​includes, Calculate several temperature rise slopes in the generated temperature change curve to filter out the maximum temperature rise slope and determine the highest temperature in the temperature change curve. The ratio of the maximum heating slope to the standard maximum heating slope is determined as the slope influence factor; The ratio of the highest temperature to the standard highest temperature is determined as the temperature influence factor; The weighted sum of the slope influence factor and the temperature influence factor is determined to be a closed eigenvalue.

7. The method for preparing gas-shielded flux-cored welding wire according to claim 6, characterized in that, The process of determining whether the closure quality of each detection point is qualified based on the closure feature value includes, If the closure feature value is less than or equal to the feature value threshold, the closure quality of the detection point is determined to be unqualified.

8. The method for preparing gas-shielded flux-cored welding wire according to claim 7, characterized in that, The process of determining whether to stop the machine based on the defect length ratio and performing closure detection on the initial welding wire includes: The ratio of the length between the farthest non-conforming test points within the hardening risk range to a preset length is defined as the defect length ratio. If the defect length ratio is less than a preset defect length ratio threshold, the system will not stop. In response to the defect length ratio being greater than or equal to the preset defect length ratio threshold, the machine is stopped to perform a closure detection on the initial welding wire.

9. The method for preparing gas-shielded flux-cored welding wire according to claim 8, characterized in that, The process of determining the initial welding wire for repairing the corresponding hardening risk zone or cutting off the initial welding wire for the corresponding hardening risk zone based on the powder leakage length ratio and adjusting the rolling deviation threshold range includes: In response to the closure detection, the initial welding wire images of each detection point contained in the initial welding wire of the hardening risk zone are acquired and analyzed to determine the detection point where powder leakage occurs. The ratio of the distance between the farthest detection points where powder leakage occurs within the hardening risk range to the distance between the farthest non-conforming detection points within the hardening risk range is called the powder leakage length ratio. In response to the fact that the powder leakage length ratio is less than a preset powder leakage length ratio threshold, the initial welding wire corresponding to the hardening risk range is determined to be repaired; In response to the powder leakage length ratio being greater than or equal to the preset powder leakage length ratio threshold, the initial welding wire in the corresponding hardening risk range is determined to be cut off and the rolling deviation threshold range is adjusted.

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