Method for detecting strip steel edge damage through guide ruler pressure

Abstract

The invention discloses a method for detecting strip steel edge damage through guide ruler pressure, and the method comprises the following steps: achieving the pressure control of a guide ruler through a servo cylinder based on the preset clamping pressure of a steel strip; when the head of the strip steel enters a coiling machine, preset clamping pressure is applied to the guide ruler through a servo system, automatic adjustment of the width of the strip steel is achieved, and a guide ruler pressure reference curve during normal rolling is established; after the strip steel enters the guide ruler, clamping pressure data of the guide ruler are collected in real time, detection of strip steel edge damage is achieved based on judgment of sudden change of clamping pressure of the guide ruler or gradient change of adjacent clamping pressure, and the method is high in detection precision: environmental interference of an optical method is avoided through direct contact type pressure detection; the data sampling frequency can reach 1kHz, the response time is less than 10ms, and the detection requirement of a high-speed production line is met.

Description

Technical Field

[0001] This invention belongs to the field of quality inspection technology in the rolling production process of metal materials, and relates to a method for detecting edge damage of strip steel by pressure of a guide ruler. Background Technology

[0002] Edge damage defects in strip steel not only affect the appearance quality of the finished product, but also cause performance degradation and shortened lifespan during service, resulting in significant losses for enterprises and users, and causing dissatisfaction among downstream users. Existing technologies have the following shortcomings:

[0003] 1. Manual visual inspection: Relies on operators to observe in real time, which is labor-intensive, has low inspection efficiency, and is easily affected by environmental factors, leading to missed detections or misjudgments; 2. Optical Imaging Inspection: For example, patent application number CN110082365A, entitled "Robot for Inspecting the Edge Quality of Steel Coils Based on Machine Vision," discloses a robot for inspecting the edge quality of steel coils based on machine vision. This mainly involves an image acquisition unit, an image processing unit, a PC unit, and an alarm processing unit. The image acquisition unit consists of an LED light source, a CCD camera, and a robotic arm, and can quickly adjust different shooting angles according to different working conditions. It can detect edge quality defects based on image information. However, the detection accuracy is unstable due to interference from factors such as ambient light and reflection from the steel strip surface, which are greatly affected by image acquisition via a camera and algorithm analysis. 3. Laser Contour Detection: For example, patent application number CN115436017A, entitled "A Laser Contour Detection Device and Detection Method," discloses a laser contour detection device and method that can achieve compatible measurement of large-size, mid-to-far infrared, and high aspect ratio laser spot contours. However, the equipment is expensive, requires strict installation accuracy, and is prone to data acquisition delays on high-speed production lines.

[0004] The aforementioned methods generally suffer from problems such as difficulty in balancing detection accuracy and production cost, insufficient real-time performance, and poor environmental adaptability, failing to meet the demands of modern strip steel production lines for high-quality and high-efficiency detection. Therefore, there is an urgent need for a method that can detect strip steel edge damage in real time during the final coiling process to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] To address the problems of low detection accuracy, poor environmental adaptability, weak anti-interference ability, complex equipment installation, and high cost in existing strip edge damage detection technologies, the present invention adopts the following technical solution: a method for detecting strip edge damage by guide ruler pressure, characterized by comprising the following steps: S1: Based on the preset clamping pressure of the steel strip, the guide ruler is pressure controlled by a servo cylinder; S2: When the strip head enters the coiler, the servo system applies a preset clamping pressure to the guide ruler to achieve automatic adjustment of the strip width and establish a guide ruler pressure reference curve during normal rolling. S3: After the strip enters the guide ruler, the guide ruler clamping pressure data is collected in real time. Based on the judgment of sudden changes in the clamping pressure of the guide ruler or the change in the gradient of adjacent clamping pressure, the edge damage of the strip can be detected.

[0006] Furthermore, the preset clamping pressure of the strip is determined as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; When the strip thickness is 8 < t ≤ 12, the preset clamping pressure is 16-26 KN; When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; When the strip thickness is 16mm < t ≤ 20mm, the preset clamping pressure is 40-60KN; When the strip thickness is greater than 20mm, the preset clamping pressure is 60-70KN. The aforementioned preset clamping pressure fluctuates within the range of -1.5KN to 1.5KN.

[0007] Furthermore: Determining edge damage in steel based on sudden pressure changes in the guide ruler involves the following process: Wavelet transform is used to remove mechanical vibration interference of ≥300Hz high frequency filtering in the guide ruler clamping pressure reference curve during normal rolling. Based on the clamping pressure signal that eliminates mechanical interference, if the clamping pressure suddenly becomes too large, it is determined that the edge of the strip has been damaged. Furthermore: the process for determining whether the strip edge is damaged when the clamping pressure suddenly becomes too large is as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; if the clamping pressure changes by ≥150%, it is determined that the strip edge is damaged. When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; if the clamping pressure changes by ≥130%, it is determined that the strip edge is damaged. When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; if the clamping pressure changes abruptly by ≥100%, it is determined that the strip edge is damaged. For strip thicknesses between 8 and 12 mm, the preset clamping pressure is 16-26 kN; if the clamping pressure changes abruptly in ≥90% of cases, the strip edge is considered to be damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure changes abruptly by ≥70%, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure changes abruptly by ≥70%, it is determined that the strip edge is damaged. When the strip thickness is greater than 20mm, the preset clamping pressure is 60-70KN. If the clamping pressure changes by ≥60%, it is determined that the strip edge is damaged.

[0008] Furthermore, determining edge damage in steel based on changes in adjacent pressure gradients involves the following process: The time series data is obtained as: P(t) = [P1, P2, ..., P n The corresponding time point is t = [t1, t2, ..., t]. n ]); The first derivative of the pressure gradient is defined as: Dp / dt≈ΔP / Δt The central difference method calculates the gradient using the points immediately before and after the current point, as shown in the formula:

[0009] in: : The pressure value at the (i+1)th time point; The pressure value at time point i-1; Δt = t i+1 - t i : Sampling time interval; When the clamping pressure gradient changes beyond the limit, it is determined that the edge of the strip is damaged.

[0010] Furthermore: the process for determining that the strip edge is damaged when the clamping pressure gradient changes beyond the limit is as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 38, it is determined that the strip edge is damaged. When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 52, it is determined that the strip edge is damaged. When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 65, it is determined that the strip edge is damaged. If the strip thickness is 8 < t ≤ 12, the preset clamping pressure is 16-26 KN; if the clamping pressure gradient exceeds the limit threshold by 95, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 132, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 175, it is determined that the strip edge is damaged. When the strip thickness is greater than 20 mm, the preset clamping pressure is 60-70 KN. If the clamping pressure changes abruptly or exceeds the threshold of 195, it is determined that the strip edge is damaged.

[0011] Furthermore, the wavelet transform employs a 5th-order Butterworth low-pass filter.

[0012] Furthermore: the guide ruler is made of 40Cr material, the clamping surface is inlaid with a polytetrafluoroethylene wear-resistant layer, and it has a built-in miniature piezoresistive pressure sensor with a detection range of 0-100KN, a nonlinear error of l±0.5%, and a response time of ≤1ms.

[0013] This invention provides a method for detecting edge damage of strip steel by measuring guide pressure, and a method for detecting edge damage of strip steel by measuring the change of guide pressure during the coiling process. This method has the characteristics of simple structure, low cost, strong real-time detection and excellent anti-interference ability.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. High detection accuracy: Direct contact pressure detection avoids environmental interference associated with optical methods; 2. High real-time performance: Data is directly transmitted through the guide pressure sensor, with a data sampling frequency of up to 1kHz and a response time of less than 10ms, meeting the detection requirements of high-speed production lines; 3. Low cost: It adopts conventional pressure sensors and simple mechanical structures; 4. Easy maintenance: The guide ruler is made of wear-resistant material, and the modular design of the sensor makes it easy to replace. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1This is a flowchart for detecting edge damage to strip steel using guide gauge pressure. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] A method for detecting edge damage of strip steel using guide gauge pressure includes the following steps: S1: Based on the preset clamping pressure of the strip, the guide ruler is pressure controlled by a servo cylinder; S2: When the strip head enters the coiler, the servo system applies a preset clamping pressure to the guide ruler to achieve automatic adjustment of the strip width and establish a guide ruler pressure reference curve during normal rolling. S3: After the strip enters the guide ruler, the guide ruler clamping pressure data is collected in real time. Based on the judgment of sudden changes in the clamping pressure of the guide ruler or the change in the gradient of adjacent clamping pressure, the edge damage of the strip can be detected.

[0020] Steps S1 / S2 / S3 are executed sequentially; The preset clamping pressure of the strip is determined as shown in Table 1: Table 1 Preset clamping pressure for strip steel

[0021] Determining edge damage of strip steel based on sudden pressure changes in the guide gauge includes the following process: Wavelet transform is used to remove mechanical vibration interference of ≥300Hz high frequency filtering in the guide ruler clamping pressure reference curve during normal rolling. Based on the clamping pressure signal that removes mechanical interference, when the clamping pressure changes too much or the change in adjacent clamping pressure gradient exceeds the limit, it is determined that the edge of the strip is damaged. The specific clamping pressure change situation is determined as shown in Table 2. Table 1. Sudden Changes in Clamping Pressure

[0022] Determining edge damage in strip steel based on changes in adjacent pressure gradients includes the following process: The gradient of the clamping pressure is calculated using the central difference method; The central difference method is a numerical differentiation technique used to calculate the derivative (gradient) of a function using discrete data points. In guide ruler pressure testing, it can calculate the rate of change of pressure over time (pressure gradient) in real time, thereby capturing pressure abrupt changes caused by edge damage. The specific principles and calculation steps are as follows: The specific principle is as follows: Suppose the time series data collected by the pressure sensor is: P(t) = [P1, P2, ..., P n (Corresponding time points t = [t1, t2, ..., t) n ]) The pressure gradient (first derivative) is defined as: Dp / dt≈ΔP / Δt The central difference method calculates the gradient using the points immediately before and after the current point, as shown in the formula:

[0023] in: : The pressure value at the (i+1)th time point; The pressure value at time point i-1; Δt = t i+1 - t i Sampling time interval; determined by the sensor frequency, such as 100Hz. Δt = 0.01s; The specific calculation steps are as follows: Collect sensor data; Pressure gradient calculation: Assuming a sampling frequency f = 1000 Hz (i.e., Δt = 0.1 s), the pressure gradient at point i is: Gi 5 ( ) When the clamping pressure gradient exceeds the limit, it is determined that the strip edge is damaged. The specific clamping pressure gradient exceeding the limit threshold is shown in Table 3. Table 3. Thresholds for Exceeding the Limit of Clamping Pressure Gradient

[0024] The wavelet transform is based on an STM32H743 microcontroller with a built-in 16-bit ADC module in the signal processing system; the digital filtering algorithm is a 5th-order Butterworth low-pass filter. The guide ruler is made of 40Cr material, with a polytetrafluoroethylene wear-resistant layer inlaid on the clamping surface. It has a built-in miniature piezoresistive pressure sensor with a detection range of 0-100KN, a nonlinear error of l±0.5%, and a response time of ≤1ms.

[0025] Example 1 A method for detecting edge damage of strip steel using guide gauge pressure includes the following steps: S1: When the strip head enters the roller conveyor area where the guide ruler is located, the guide ruler begins to contact the edge of the strip and applies a preset clamping pressure through the servo system. S2: When the guide ruler interacts with the edge of the strip, the pressure sensor collects the clamping pressure data of the guide ruler in real time and uploads it to the production control system.

[0026] The guide gauge is made of 40Cr material, with a PTFE wear-resistant layer inlaid on the clamping surface. It has a built-in miniature piezoresistive pressure sensor (model: MPX5010DP) with a detection range of 0-100KN, a nonlinear error of l±0.5%, and a response time of ≤1ms. Based on the guide gauge control pressure issued by the secondary model, the guide gauge can achieve 3-100KN pressure closed-loop control through a servo cylinder. S3: The production control system compares the received pressure data. When the clamping pressure meets the set value, the data is displayed as normal and the process ends. When the clamping pressure changes too suddenly or the gradient change of adjacent clamping pressure exceeds the limit, the data will be displayed as abnormal and a damage judgment will be triggered.

[0027] After the damage detection is triggered, the detection results are transmitted to the production line control system for record saving. The audible and visual alarm starts to sound, and the edge-damaged strip steel is detected. The efficiency and accuracy of accurately detecting edge-damaged strip steel are both >90%.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting edge damage of strip steel by pressure testing with a guide ruler, characterized in that: Includes the following steps: S1: Based on the preset clamping pressure of the steel strip, the guide ruler is pressure controlled by a servo cylinder; S2: When the strip head enters the coiler, the servo system applies a preset clamping pressure to the guide ruler to achieve automatic adjustment of the strip width and establish a guide ruler pressure reference curve during normal rolling. S3: After the strip enters the guide ruler, the guide ruler clamping pressure data is collected in real time. Based on the judgment of sudden changes in the clamping pressure of the guide ruler or the change in the gradient of adjacent clamping pressure, the edge damage of the strip can be detected.

2. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 1, characterized in that: The preset clamping pressure of the strip is determined as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; When the strip thickness is 8 < t ≤ 12, the preset clamping pressure is 16-26 KN; When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; When the strip thickness is 16mm < t ≤ 20mm, the preset clamping pressure is 40-60KN; When the strip thickness is greater than 20mm, the preset clamping pressure is 60-70KN. The aforementioned preset clamping pressure fluctuates within the range of -1.5KN to 1.5KN.

3. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 1, characterized in that: Determining edge damage in steel based on sudden pressure changes using a guide ruler involves the following process: Wavelet transform is used to remove mechanical vibration interference of ≥300Hz high frequency filtering in the guide ruler clamping pressure reference curve during normal rolling. Based on the clamping pressure signal that eliminates mechanical interference, if the clamping pressure suddenly becomes too large, it is determined that the edge of the strip has been damaged.

4. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 3, characterized in that: The process for determining whether the strip edge is damaged when the clamping pressure suddenly becomes too large is as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; if the clamping pressure changes by ≥150%, it is determined that the strip edge is damaged. When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; if the clamping pressure changes by ≥130%, it is determined that the strip edge is damaged. When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; if the clamping pressure changes abruptly by ≥100%, it is determined that the strip edge is damaged. For strip thicknesses between 8 and 12 mm, the preset clamping pressure is 16-26 kN; if the clamping pressure changes abruptly in ≥90% of cases, the strip edge is considered to be damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure changes abruptly by ≥70%, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure changes abruptly by ≥70%, it is determined that the strip edge is damaged. When the strip thickness is greater than 20mm, the preset clamping pressure is 60-70KN. If the clamping pressure changes by ≥60%, it is determined that the strip edge is damaged.

5. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 1, characterized in that: Determining edge damage in steel based on changes in adjacent pressure gradients involves the following process: The time series data is obtained as: P(t) = [P1, P2, ..., P n ], corresponding to time point t = [t1, t2, ...,t n ]); The first derivative of the pressure gradient is defined as: Dp / dt≈ΔP / Δt The central difference method calculates the gradient using the points immediately before and after the current point, as shown in the formula: in: : The pressure value at the (i+1)th time point; Let be the pressure value at the (i-1)th time point; Δt = t i+1 -t i : Sampling time interval; When the clamping pressure gradient changes beyond the limit, it is determined that the edge of the strip is damaged.

6. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 1, characterized in that: The process for determining that the strip edge is damaged when the clamping pressure gradient changes beyond the limit is as follows: When the strip thickness is 1.4mm≤t≤2.5mm, the preset clamping pressure is 4-6 KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 38, it is determined that the strip edge is damaged. When the strip thickness is 2.5mm < t ≤ 4mm, the preset clamping pressure is 6-10KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 52, it is determined that the strip edge is damaged. When the strip thickness is 4mm < t ≤ 8mm, the preset clamping pressure is 10-16KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 65, it is determined that the strip edge is damaged. If the strip thickness is 8 < t ≤ 12, the preset clamping pressure is 16-26 KN; if the clamping pressure gradient exceeds the limit threshold by 95, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 132, it is determined that the strip edge is damaged. When the strip thickness is 12mm < t ≤ 16mm, the preset clamping pressure is 26-40KN; if the clamping pressure gradient is greater than or equal to the over-limit threshold of 175, it is determined that the strip edge is damaged. When the strip thickness is greater than 20 mm, the preset clamping pressure is 60-70 KN. If the clamping pressure changes abruptly or exceeds the threshold of 195, it is determined that the strip edge is damaged.

7. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 3, characterized in that: The wavelet transform uses a 5th-order Butterworth low-pass filter.

8. The method for detecting edge damage of strip steel by pressure testing with a guide ruler according to claim 3, characterized in that: The guide ruler is made of 40Cr material, with a polytetrafluoroethylene wear-resistant layer inlaid on the clamping surface. It has a built-in miniature piezoresistive pressure sensor with a detection range of 0-100KN, a nonlinear error of l±0.5%, and a response time of ≤1ms.

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