Casting blank surface defect detection method and related equipment

Abstract

The invention discloses a casting blank surface defect detection method and related equipment, and relates to the technical field of continuous casting billets.The method comprises the steps that the steel grade carbon equivalent of a to-be-detected casting blank is calculated; under the condition that the steel grade carbon equivalent is smaller than or equal to a preset value, the casting blank to be detected is subjected to water leaching phosphorus removal operation, and a pretreated casting blank is obtained; and carrying out surface defect detection on the pretreated casting blank to obtain a detection result. According to the method, the steel grade carbon equivalent is calculated, the surface temperature of the casting blank is accurately controlled based on the cooling phase change type, and the detection rate of the surface defects of the casting blank is increased by combining the water leaching dephosphorization operation and the optical image processing technology.

Description

Technical Field

[0001] This application relates to the field of continuous casting billet technology, and in particular to a method and related equipment for detecting surface defects in billets. Background Technology

[0002] During the continuous casting billet production process, defects such as cracks, scale, and vibration marks often exist on the billet surface. If these defects are not detected and treated in a timely manner, they will directly affect subsequent rolling processes, resulting in substandard steel plate surface quality. Traditional methods for detecting surface defects in billets mainly rely on optical image processing technology. However, due to the presence of a large amount of iron oxide scale and residual protective slag on the billet surface, the detection difficulty increases, and misjudgments or missed detections are prone to occur. Therefore, there is an urgent need for a method for detecting surface defects in billets to solve the aforementioned problems. Summary of the Invention

[0003] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0004] In a first aspect, this application provides a method for detecting surface defects in cast billets, comprising: Calculate the carbon equivalent of the steel grade in the billet to be inspected; When the carbon equivalent of the steel is less than or equal to the preset value, the billet to be inspected is subjected to water immersion descaling to obtain a pretreated billet. Surface defects were detected on the pretreated billet, and the results were obtained.

[0005] In some embodiments, the process includes, prior to the water immersion descaling operation on the billet to be inspected, the following steps: Based on the carbon equivalent of the steel grade, determine the cooling phase transformation type of the billet to be inspected; The surface temperature of the billet to be inspected is controlled based on the type of cooling phase transformation.

[0006] In some implementations, the surface temperature of the billet under inspection is controlled based on the type of cooling phase transformation, including: When the cooling phase transformation type is martensitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the martensitic phase transformation end temperature and the first error value. When the cooling phase transformation type is bainitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the bainitic phase transformation end temperature and the second error value. When the cooling phase transformation type is ferritic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the temperature at which ferrite begins to precipitate from austenite and the third error value.

[0007] In some implementations, the water immersion phosphorus removal operation is carried out based on a phosphorus removal tank, the water temperature of the phosphorus removal tank is a second preset temperature, the water flow rate of the phosphorus removal tank is greater than or equal to a preset speed, and the single water immersion phosphorus removal time of the phosphorus removal tank is less than or equal to a preset time.

[0008] In some implementations, the pretreated billet undergoes surface defect detection to obtain detection results, including: The pre-treated billet is flipped using a steel flipping machine so that the upper and lower surfaces of the pre-treated billet can be inspected. High-resolution imaging of the upper and lower surfaces is performed using optical image processing technology, and the results are compared with a preset defect feature library to output the detection results. The flipping action of the steel turning machine is driven by a motor.

[0009] In some embodiments, prior to surface defect detection of the pretreated billet, the following steps are also included: Compressed air is used to remove residual water from the surface of the pretreated billet, thus optimizing the surface inspection environment.

[0010] In some implementations, the preset value is 0.5.

[0011] Secondly, this application proposes a device for detecting surface defects in cast billets, comprising: The billet pre-test unit is used to calculate the carbon equivalent of the steel grade in the billet to be tested. The billet processing unit is used to perform water immersion descaling on the billet to be inspected when the carbon equivalent of the steel grade is less than or equal to a preset value, so as to obtain a pretreated billet. The billet inspection unit is used to inspect the surface defects of the pretreated billet and obtain the inspection results.

[0012] Thirdly, an electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program stored in the memory to implement the steps of the method for detecting surface defects of a cast billet according to any one of the first aspects.

[0013] Fourthly, this application also proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for detecting surface defects of cast billets according to any one of the first aspects.

[0014] In summary, this application improves the detection rate of surface defects in billets by calculating the carbon equivalent of the steel grade and precisely controlling the surface temperature of the billet based on the cooling phase transformation type, combined with water immersion descaling and optical image processing technology. Specifically, the water immersion descaling operation effectively removes iron oxide scale and residual protective slag from the billet surface, optimizing the detection environment of the optical inspection system; the combination of a steel turning machine and a compressed air purging device enables comprehensive inspection of the upper and lower surfaces of the billet, avoiding missed detections and misjudgments; simultaneously, the temperature control mechanism based on the carbon equivalent of the steel grade ensures that the surface temperature of the billet is within the optimal range under different cooling phase transformation conditions, further improving the defect detection rate. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart of a method for detecting surface defects in a cast billet provided in an embodiment of this application; Figure 2 This is a schematic diagram of the cooling and dephosphorization process provided in an embodiment of this application; Figure 3 This is a schematic diagram of the surface inspection of the cast billet provided in an embodiment of this application; Figure 4 This is a schematic diagram of the test results for steel grade A provided in an embodiment of this application; Figure 5 This is a schematic diagram comparing the test results of steel grade A provided in the embodiments of this application; Figure 6 This is a schematic diagram of the test results for steel grade B provided in an embodiment of this application; Figure 7 This is a schematic diagram comparing the test results of steel grade B provided in the embodiments of this application; Figure 8 This is a schematic diagram of the test results for C steel grade provided in an embodiment of this application; Figure 9 This is a schematic diagram comparing the test results of C steel grade provided in the embodiments of this application; Figure 10 A schematic diagram of a device for detecting surface defects in a cast billet, provided in an embodiment of this application; Figure 11 This is a schematic diagram of a device for detecting surface defects in cast billets, provided in an embodiment of this application. Detailed Implementation

[0016] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0017] Please see Figure 1 This is a schematic flowchart of a method for detecting surface defects in a cast billet according to an embodiment of this application, which may specifically include: S110. Calculate the carbon equivalent of the steel grade of the billet to be inspected; For example, the carbon equivalent of a steel grade is a core parameter characterizing the comprehensive influence of alloying elements on the phase transformation properties and cooling behavior of the material. Essentially, it indirectly reflects the tendency of a steel grade to undergo martensitic, bainitic, or ferrite phase transformations during cooling by quantifying the equivalent effects of carbon and alloying elements (such as manganese, chromium, and silicon) on the hardenability and microstructure transformation of the steel. The calculation of this parameter is based on the chemical composition of the steel, aiming to simplify complex alloy systems into an equivalent carbon content index, thereby providing a theoretical basis for the precise control of subsequent processes.

[0018] In methods for detecting surface defects in cast billets, calculating the carbon equivalent is fundamental to determining the type of cooling phase transformation and temperature control strategies. The carbon equivalent allows for the prediction of the phase transformation path of the steel grade at different cooling rates, thus enabling dynamic adjustment of the billet's entry temperature range into the bath. For example, steel grades with lower carbon equivalents are more prone to ferritic phase transformation, while higher carbon equivalents may induce martensitic phase transformation. This correlation ensures that the temperature control during water immersion descaling is highly compatible with the steel grade characteristics, providing scientific support for effectively removing surface iron oxide scale and residual impurities.

[0019] S120. When the carbon equivalent of the steel grade is less than or equal to the preset value, the billet to be inspected is subjected to water immersion descaling to obtain a pretreated billet. For example, when the carbon equivalent of a steel grade is less than or equal to a preset value, it indicates that the alloy composition of the steel grade is relatively simple, and the phase transformation behavior during cooling is relatively stable, making it suitable for water immersion descaling. The core principle of water immersion descaling is to utilize the cooling, scouring, and vaporization effects of water to quickly peel off the iron oxide scale and residual mold flux from the surface of the cast billet. This process not only relies on the physical properties of water but also ensures efficient removal of surface impurities by controlling the water temperature, flow rate, and immersion time, while avoiding damage to the surface of the cast billet.

[0020] The effectiveness of water immersion descaling is closely related to its temperature control. When the surface temperature of the billet is within a reasonable range, the cooling and vaporization effects of water can generate sufficient impact force to loosen and remove the iron oxide scale. This operation not only significantly improves surface cleanliness but also provides a clearer inspection environment for subsequent optical inspection systems, thereby greatly improving the defect detection rate. The pretreated billets obtained through water immersion descaling exhibit significantly improved surface quality, laying a solid foundation for subsequent defect detection.

[0021] S130. Surface defects are detected on the pretreated billet, and the detection results are obtained.

[0022] For example, after the pre-treated billet undergoes a water immersion descaling operation, the surface iron oxide scale and residual impurities are effectively removed, providing a clear inspection environment for the optical inspection system. The core principle of surface defect detection is to use high-resolution optical imaging technology to scan the surface of the billet, capture the morphological features of defects such as cracks, scabs, and vibration marks, and compare and analyze them with a preset defect feature library. This process automatically identifies the defect type, location, and severity through image processing algorithms, thereby achieving efficient and accurate defect detection.

[0023] In some instances, the default value is 0.5.

[0024] For example, when the carbon equivalent of steel exceeds 0.5, the steel's crack susceptibility increases significantly. This is because high-carbon-equivalent steels are more prone to martensitic or bainitic phase transformations during cooling. These phase transformations are accompanied by large structural stresses and volume changes. Especially when a high-temperature billet is suddenly placed in a descaling bath, the rapid cooling rate exacerbates the phase transformation stress, leading to cracks or even fractures in the billet during subsequent cutting or reheating. Therefore, controlling the carbon equivalent to less than or equal to 0.5 ensures that the steel has low crack susceptibility during cooling, thereby avoiding quality problems caused by phase transformation stress.

[0025] By limiting the carbon equivalent to 0.5 or less, the risk of phase transformation in the steel during cooling can be effectively reduced, ensuring that the billet maintains a stable microstructure within the temperature control range of the descaling tank. This not only reduces the likelihood of crack formation but also improves the reliability and safety of the billet in subsequent processing. Therefore, controlling the carbon equivalent is a key prerequisite for the successful implementation of water immersion descaling operations, providing a stable material basis for the detection of surface defects in the billet.

[0026] In some instances, the process of descaling the billet under inspection before water immersion also includes: Based on the carbon equivalent of the steel grade, determine the cooling phase transformation type of the billet to be inspected; Based on the type of cooling phase transformation, the surface temperature of the billet under inspection is controlled, including: When the cooling phase transformation type is martensitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the martensitic phase transformation end temperature and the first error value. When the cooling phase transformation type is bainitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the bainitic phase transformation end temperature and the second error value. When the cooling phase transformation type is ferritic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the temperature at which ferrite begins to precipitate from austenite and the third error value.

[0027] For example, the carbon equivalent of the steel grade is a key parameter determining the type of phase transformation during cooling. By calculating the carbon equivalent, the type of phase transformation that may occur during cooling can be predicted, such as martensitic, bainitic, or ferritic transformation. Each type of phase transformation corresponds to a different temperature range and cooling rate. Therefore, determining the cooling phase transformation type based on the carbon equivalent is fundamental to ensuring reasonable temperature control of the billet during subsequent water immersion descaling. This step provides a scientific basis for subsequent temperature control, ensuring that the billet does not develop structural stress or cracks due to improper temperature during descaling.

[0028] When the cooling phase transformation is martensitic, the surface temperature of the billet is controlled to be greater than a first preset temperature and less than or equal to the difference between the martensitic transformation end temperature and a first error value. This temperature range ensures that when the billet enters the descaling tank, the surface temperature is neither too high, making it difficult to remove iron oxide scale, nor too low, inducing martensitic transformation stress, thereby avoiding crack formation. Similarly, for bainitic and ferritic phase transformations, the surface temperature of the billet is controlled within the range of the difference between the bainitic transformation end temperature and a second error value, and within the range of the difference between the temperature at which ferrite begins to precipitate from austenite and a third error value, respectively.

[0029] The aforementioned temperature control strategy ensures that the cooling rate of the billet in the descaling bath matches the phase transformation characteristics, effectively removing surface iron oxide scale and residual impurities while avoiding cracking caused by phase transformation stress. This method significantly improves the accuracy and reliability of billet surface defect detection, providing a high-quality inspection environment for subsequent optical inspection systems.

[0030] It should be noted that in this embodiment, the first preset temperature can be set to 100℃, the first error value is 50 to 100℃, the second error value is 100 to 200℃, and the third error value is 300 to 400℃. In actual production scenarios, the measurement distance is a significant factor when measuring slab temperature. When using non-contact temperature measuring devices, such as infrared thermometers, the measurement distance directly affects the measurement accuracy. If the measurement distance is too far, the radiant energy received by the slab will be weakened, resulting in a measured temperature lower than the actual temperature. Conversely, if the measurement distance is too close, it may be affected by environmental factors around the slab, such as heat or dust, which will also cause deviations in the measurement results. In addition, human operation can also introduce errors into the measurement results. Different operators may have different operating techniques, measurement angles, and timing of measurements when using temperature measuring devices. For example, if the operator fails to record the temperature data in time when the device displays a stable value, or if the measurement angle changes due to instability of the handheld device during the measurement process, the measured slab temperature will be inaccurate.

[0031] Therefore, to address the unavoidable errors caused by measurement distance and human operation, an error range is specified when controlling the surface temperature of the billet. This error range was determined after comprehensively considering various practical influencing factors and verifying it through extensive experimental and practical data. It ensures that, even with measurement errors, the surface temperature of the billet can be controlled within a reasonable range during actual production, minimizing interference with the billet's cooling phase transformation process, guaranteeing the smooth progress of subsequent operations such as water immersion descaling, and ensuring stable billet quality.

[0032] like Figure 2 and Figure 3 The figures shown are schematic diagrams of the cooling and descaling process and the surface inspection of the billet provided in the embodiments of this application, respectively; wherein, 1 is the billet, 2 is the roller conveyor, 3 is the temperature measuring device, 4 is the billet hoisting device, 5 is the descaling tank, 6 is the descaling tank water supply system, 7 is the descaling tank drainage system, 8 is the descaling tank cooling water, 9 is the purging device, 10 is the surface quality inspection system, 11 is the lighting device, and 12 is the steel turning machine.

[0033] The inspection of the billet begins during the billet transportation process. Billet 1 is transported on roller conveyor 2, and during this process, temperature measuring device 3 measures the temperature of billet 1. Once the temperature of billet 1 meets the predetermined requirements, billet hoisting device 4 lifts it to the descaling tank 5.

[0034] The descaling tank 5 is a key piece of equipment for descaling the cast billet. The descaling tank water supply system 6 serves as the cooling water inlet, providing circulating cooling water 8 to the descaling tank 5. Descaling of the cast billet 1 is performed through water immersion to remove impurities from its surface. After the descaling operation is completed, the descaling tank drainage system 7 serves as the cooling water outlet, draining the water from the descaling tank 5. This, in conjunction with the descaling tank water supply system 6, ensures the flow and circulation of cooling water.

[0035] After descaling, the billet 1 is hoisted to the inspection station. At the inspection station, the purging device 9 uses compressed air to blow away any residual moisture on the surface of the billet 1, preventing residual moisture from interfering with subsequent inspections. Then, with the assistance of the lighting device 11, the surface quality inspection system 10 performs surface quality inspection on the billet 1. If it is necessary to inspect the quality of both the upper and lower surfaces of the billet 1, the billet flipping machine 12 is activated to flip the billet 1 to meet the requirements of comprehensive inspection.

[0036] In some instances, the water immersion phosphorus removal operation is implemented based on a phosphorus removal tank, where the water temperature is a second preset temperature, the water flow rate in the phosphorus removal tank is greater than or equal to a preset rate, and the single water immersion phosphorus removal time in the phosphorus removal tank is less than or equal to a preset time.

[0037] For example, the core of water immersion descaling lies in the efficient removal of iron oxide scale and residual mold flux through the interaction between the water in the descaling tank and the surface of the cast billet. The water temperature, water flow rate, and immersion time in the descaling tank are the key process parameters for achieving this goal.

[0038] The control of water temperature (the second preset temperature) directly affects the cooling and vaporization effect of water. If the water temperature is too high, it will reduce the cooling rate and weaken the peeling effect of iron oxide scale; if the water temperature is too low, it may cause a sudden drop in the surface temperature of the billet, triggering phase transformation stress or cracks. By maintaining the water temperature between 20 and 30°C, the cooling and vaporization of water can be fully guaranteed, while avoiding the adverse effects of temperature fluctuations on the surface quality of the billet.

[0039] Controlling the water flow velocity (≥ preset velocity) is another crucial factor in ensuring efficient removal of iron oxide scale. High-speed water flow enhances the scouring effect on the billet surface, accelerating the peeling and removal of iron oxide scale. If the water flow velocity is too low, iron oxide scale may remain due to insufficient scouring force; while excessively high flow velocity may cause mechanical damage to the billet surface. By controlling the water flow velocity to ≥0.1 m / s, the scouring effect can be guaranteed while avoiding additional damage to the billet surface.

[0040] The control of the single water immersion descaling time (≤ preset time) is to balance descaling effect and production efficiency. Too short an immersion time may result in incomplete removal of iron oxide scale; while too long an immersion time may increase the risk of phase transformation stress due to the continuous drop in the surface temperature of the cast billet. By controlling the single immersion time to ≤30s and combining it with multiple immersion operations, surface cleanliness can be ensured while avoiding temperature runaway caused by prolonged immersion. This dynamically adjusted immersion strategy significantly improves descaling efficiency and provides a high-quality pre-treated cast billet for subsequent surface defect detection.

[0041] It should be noted that in this embodiment, the second preset temperature can be set to 20 to 30°C, the preset speed can be set to 0.1 m / s, and the preset time can be set to 30 s.

[0042] In the water immersion descaling process for cast billets, the absence of loose iron oxide scale on the surface is a crucial indicator of descaling effectiveness. When no significant iron oxide scale residue remains on the billet surface, the water immersion descaling operation has achieved the desired effect. Generally, for a 200mm thick billet, a single water immersion descaling session of approximately 30 seconds is sufficient to remove the surface iron oxide scale. This time range is an empirical value derived from the comprehensive balance of water cooling, scouring, and vaporization effects with the billet surface temperature and water flow velocity. This approach ensures effective descaling while avoiding temperature drops or reduced production efficiency due to excessively long immersion times.

[0043] By combining manual observation with time control, operators can quickly assess the descaling effect and adjust the number of immersion cycles or the duration of immersion as needed to ensure the surface cleanliness of the cast billet meets subsequent testing requirements. This intuitive and flexible assessment method not only simplifies the operation process but also improves the adaptability and reliability of the descaling process.

[0044] In some instances, surface defect detection is performed on pretreated billets, and the detection results include: The pre-treated billet is flipped using a steel flipping machine so that the upper and lower surfaces of the pre-treated billet can be inspected. High-resolution imaging of the upper and lower surfaces is performed using optical image processing technology, and the results are compared with a preset defect feature library to output the detection results. The flipping action of the steel turning machine is driven by a motor.

[0045] For example, during the production process, defects may occur on both the upper and lower surfaces of the cast billet. Inspecting only one side cannot meet the comprehensive requirements of quality inspection. The billet turning machine is driven by a motor, and the power provided by the motor can precisely control the angle and speed of the turning action. Through precise mechanical structure design, the turning machine can stably turn the cast billet 180°, flipping the surface that was originally on the bottom to the top, making it easier for subsequent inspection equipment to inspect. This turning operation ensures that both the upper and lower surfaces of the cast billet can be fully inspected, avoiding the omission of defects caused by single-sided inspection, thereby improving the accuracy and reliability of the inspection results.

[0046] High-resolution imaging of the upper and lower surfaces of a cast billet using optical image processing technology is the core method for acquiring surface information. Based on optical principles, optical image processing technology utilizes high-resolution image acquisition equipment (such as industrial cameras) to capture detailed information about the billet surface. With the aid of an illumination device, light is uniformly irradiated onto the billet surface, and the reflected light is received by the image acquisition equipment, forming a high-resolution image. These images clearly present the texture, shape, color, and other features of the billet surface, recording minute defects such as cracks, holes, and pits in image form. This non-contact inspection method has advantages such as high inspection speed, high accuracy, and no damage to the billet, meeting the needs of modern steel production for rapid inspection of billet surface quality.

[0047] Comparing the acquired high-resolution images with a pre-defined defect feature library and outputting the detection results is a crucial step in determining whether defects exist on the surface of the cast billet. The pre-defined defect feature library is established by analyzing and processing a large number of known defective cast billet surface images, containing defect features of various types, sizes, and shapes. During the comparison, advanced image recognition algorithms are used to match and analyze each acquired cast billet surface image with images in the pre-defined defect feature library. The algorithm determines whether similar defect features exist on the cast billet surface based on image feature parameters such as edges, texture, and grayscale. If similar features are detected, the presence of the corresponding type of defect on the cast billet surface can be confirmed. Finally, the system outputs the detection results in an intuitive manner, providing accurate information for subsequent production decisions, such as determining whether the cast billet is qualified and whether repair or scrapping is necessary.

[0048] In some instances, the process of inspecting the surface defects of the pretreated billet also includes: Compressed air is used to remove residual water from the surface of the pretreated billet, thus optimizing the surface inspection environment.

[0049] For example, compressed air has high pressure and flow rate. When compressed air is sprayed onto the surface of the billet, the high-speed airflow interacts with residual water. On one hand, the impact force of the high-speed airflow can break the surface tension of the water, causing the residual water to form fine droplets and be blown away; on the other hand, the flow of the airflow accelerates the evaporation of water, further promoting the removal of residual water. In this way, residual water on the surface of the billet can be effectively removed, avoiding interference with subsequent testing due to residual water.

[0050] The presence of residual water can have several adverse effects on the detection of surface defects in cast billets. In optical image processing inspection, residual water alters the reflective properties of the billet surface, leading to interference factors such as light spots and shadows in the acquired images, affecting image clarity and accuracy, and consequently making it difficult to accurately identify defect features. Furthermore, moisture may react chemically with certain substances on the billet surface, altering the surface condition and also affecting the reliability of the inspection results. Therefore, removing residual water from the pretreated billet surface using compressed air before surface defect inspection provides a clean and stable surface environment, ensuring that the inspection equipment can accurately acquire surface information, improving the accuracy and reliability of the inspection results, and guaranteeing the accuracy of subsequent production decisions.

[0051] The technical solution of this application will be further described in detail below through specific embodiments.

[0052] Example 1 describes surface inspection of a certain grade A steel billet. Figure 4 and Figure 5 As shown, the carbon equivalent of the steel grade A billet was first calculated using the formula Ceq=C+(Mn / 6)+(Cr+V+Mo) / 5+(Cu+Ni) / 15, yielding a carbon equivalent Ceq=0.48. It was determined that the billet underwent a martensitic transformation during cooling, with the transformation ending at approximately 338℃. Therefore, to ensure billet quality and subsequent processing effectiveness, the billet's temperature entering the descaling tank needed to be less than (238-288)℃. In actual operation, after cutting and cooling, the billet entered the descaling tank when its surface temperature was approximately 275℃. The descaling tank used circulating cooling water, with the water temperature maintained at a stable 25℃. The cooling water flowed unidirectionally at a velocity of 0.15m / s. The billet underwent two water immersion descaling operations in the descaling tank, with each immersion lasting 10 seconds. After the billet leaves the descaling tank, compressed air is used to blow away the residual water on its surface. Then, a steel turning machine is used to inspect the quality of the upper and lower surfaces of the billet.

[0053] from Figure 4As can be clearly seen, after the above processing, the surface of the billet is clean, and the defects on the edge can be clearly observed. This indicates that the descaling and testing process effectively removes impurities from the surface of the billet, enabling the testing equipment to accurately identify the defects on the surface of the billet.

[0054] In contrast, in Comparative Example 1, the same steel grade A billet was used, with identical carbon equivalent calculations, similar martensitic transformation completion temperatures, and consistent temperature requirements for the billet entering the descaling tank. However, in this comparative example, the surface temperature of the billet entering the descaling tank after cutting and warming was only about 25°C. After undergoing the same descaling tank circulating cooling water conditions, and after exiting the tank, the billet was cleaned with compressed air to remove residual water and inspected using a steel turning machine. Figure 5 It is evident that iron oxide scale remains on the surface of the billet, making it difficult to distinguish between defects and iron oxide scale, thus hindering effective detection of surface defects in the billet.

[0055] A comparison between Specific Example 1 and Comparative Example 1 demonstrates the significant impact of parameters such as the surface temperature of the cast billet upon entering the descaling tank on the descaling effect and subsequent surface defect detection. The method proposed in this application effectively improves the descaling effect and increases the detection rate and accuracy of surface defects in the cast billet.

[0056] Example 2 describes surface inspection of a B-grade steel billet. Figure 6 and Figure 7 As shown. First, based on the carbon equivalent calculation formula Ceq=C+(Mn / 6)+(Cr+V+Mo) / 5+(Cu+Ni) / 15, the carbon equivalent Ceq of steel grade B billet is calculated to be 0.49. It is determined that the billet undergoes a bainitic phase transformation during cooling, with the transformation ending at approximately 386℃. Based on this, to ensure the quality of the billet and the smooth progress of subsequent processing, it is determined that the temperature of the billet entering the descaling tank must be less than (186 to 286)℃. In actual operation, after cutting and cooling, the billet enters the descaling tank when its surface temperature is approximately 280℃. The descaling tank uses circulating cooling water, with the water temperature maintained stably at 25℃. The cooling water flows in one direction at a velocity of 0.15m / s. The billet undergoes two water immersion descaling operations in the descaling tank, with each water immersion descaling operation lasting 15s.

[0057] After the billet leaves the descaling tank, compressed air is used to blow away any residual water from its surface. Then, a billet turning machine is used to inspect the quality of the upper and lower surfaces. Figure 6 As can be clearly seen, after the above processing steps, the surface of the billet is clean, and the surface defects are clearly visible. This indicates that the descaling and testing process effectively removed impurities from the surface of the billet, enabling the testing equipment to accurately identify the defects on the surface of the billet.

[0058] In Comparative Example 2, the same steel grade B billet was used, with identical carbon equivalent calculations and similar bainitic transformation completion temperatures, and the same temperature requirement for the billet entering the descaling tank. However, the surface temperature of the billet entering the descaling tank after cutting and warming was approximately 276°C, and only one water immersion descaling operation was performed. After undergoing the same descaling tank circulating cooling water conditions, and after exiting the tank, the residual water was blown away with compressed air, and the billet was inspected using a turning machine, the surface temperature of the billet entering the descaling tank was significantly lower than that of the steel grade B billet. Figure 7 It is clearly visible that some impurities remain on the surface of the cast billet, which will interfere with subsequent defect detection and affect the accuracy of the detection.

[0059] The comparison between Example 2 and Comparative Example 2 demonstrates the advantages of the proposed method in detecting surface defects in cast billets. By controlling key process parameters such as the temperature of the cast billet entering the descaling tank and the number of water immersion descaling cycles, the method of this application can more effectively remove impurities from the surface of the cast billet, providing excellent surface conditions for subsequent optical image processing and inspection. This makes defect detection more accurate during the inspection process, improving the detection rate and accuracy of surface defects in cast billets.

[0060] Example 3 describes surface inspection of a C-grade steel billet. Figure 8 and Figure 9 As shown. First, the carbon equivalent of the steel grade C billet was calculated using the formula Ceq=C+(Mn / 6)+(Cr+V+Mo) / 5+(Cu+Ni) / 15, yielding a carbon equivalent Ceq=0.392. It was determined that the billet underwent a ferrite phase transformation during cooling, with the transformation ending at approximately 728℃. Based on this, to ensure billet quality and subsequent processing effectiveness, the billet temperature entering the descaling tank needed to be less than (328-428)℃. In actual operation, after cutting and cooling, the C billet entered the descaling tank when its surface temperature was approximately 260℃. The descaling tank used circulating cooling water, with the water temperature maintained at a stable 25℃. The cooling water flowed unidirectionally at a velocity of 0.15m / s. The billet underwent two water immersion descaling operations in the descaling tank, with each immersion descaling session lasting 20s.

[0061] After the billet leaves the descaling tank, compressed air is used to blow away any residual water from its surface. Then, a billet turning machine is used to inspect the quality of the upper and lower surfaces. Figure 8 As can be seen, the surface edge defects of the billet after descaling have clear morphology, which provides good conditions for subsequent inspection and facilitates accurate identification of defects by inspection equipment.

[0062] In Comparative Example 3, the same C-grade steel billet was used, with identical carbon equivalent calculations and similar ferrite phase transformation completion temperatures, and the same temperature requirement for the billet entering the descaling tank. However, the surface temperature of the billet entering the descaling tank after cutting and warming was only about 40°C. After undergoing the same descaling tank circulating cooling water conditions, and after cleaning residual water with compressed air and testing with a steel turning machine, the billet's low water entry temperature made it difficult to completely remove surface iron oxide scale, leaving some residue, such as... Figure 9 As shown.

[0063] Please see Figure 10 The diagram below illustrates the structure of a device for detecting surface defects in cast billets, as provided in an embodiment of this application. The device includes: The billet inspection unit 21 is used to calculate the carbon equivalent of the steel grade of the billet to be inspected. The billet processing unit 22 is used to perform water immersion descaling on the billet to be inspected when the carbon equivalent of the steel grade is less than or equal to a preset value, so as to obtain a pretreated billet. The billet inspection unit 23 is used to inspect the surface defects of the pretreated billet and obtain the inspection results.

[0064] Please see Figure 11 This application also provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor. When the processor 320 executes the computer program 311, it implements the steps of any method of a device for detecting surface defects of a billet.

[0065] Since the electronic device described in this embodiment is the device used to implement the billet surface defect detection device in the embodiment of this application, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the method described in the embodiment of this application. Therefore, how the electronic device implements the method in the embodiment of this application will not be described in detail here. Any device used by those skilled in the art to implement the method in the embodiment of this application is within the scope of protection of this application.

[0066] In practice, when the computer program 311 is executed by the processor, it can implement any of the embodiments corresponding to the first aspect.

[0067] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0068] Those skilled in the art will understand that embodiments of this application can provide methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-readable program code.

[0069] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0070] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0071] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0072] This application also provides a computer program product, which includes computer software instructions that, when executed on a processing device, cause the processing device to perform... Figure 1 The flowchart of a method for detecting surface defects of a cast billet in the corresponding embodiment.

[0073] A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0074] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0075] In the several embodiments provided in this application, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0076] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0077] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0078] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0079] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0080] Although preferred embodiments have been described in this specification, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this specification.

[0081] Obviously, those skilled in the art can make various modifications and variations to this specification without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, this specification is also intended to include such modifications and variations.

Claims

1. A method for detecting surface defects in cast billets, characterized in that, The method includes: Calculate the carbon equivalent of the steel grade in the billet to be inspected; When the carbon equivalent of the steel grade is less than or equal to a preset value, the billet to be inspected is subjected to water immersion dephosphorization to obtain a pretreated billet. The surface defects of the pretreated billet were detected, and the detection results were obtained.

2. The method according to claim 1, characterized in that, Before performing water immersion descaling on the billet to be inspected, the process also includes: Based on the carbon equivalent of the steel grade, the cooling phase transformation type of the billet to be inspected is determined; The surface temperature of the billet to be inspected is controlled based on the type of cooling phase transformation.

3. The method according to claim 2, characterized in that, The step of controlling the surface temperature of the billet under inspection based on the cooling phase transformation type includes: When the cooling phase transformation type is martensitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the martensitic phase transformation end temperature and the first error value. When the cooling phase transformation type is bainitic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than the first preset temperature and less than or equal to the difference between the bainitic phase transformation end temperature and the second error value. When the cooling phase transformation type is ferritic phase transformation, the surface temperature of the billet to be inspected is controlled to be greater than a first preset temperature and less than or equal to the difference between the temperature at which ferrite begins to precipitate from austenite and a third error value.

4. The method according to claim 1, characterized in that, The water immersion phosphorus removal operation is implemented based on a phosphorus removal tank, the water temperature of the phosphorus removal tank is a second preset temperature, the water flow velocity of the phosphorus removal tank is greater than or equal to a preset velocity, and the single water immersion phosphorus removal time of the phosphorus removal tank is less than or equal to a preset time.

5. The method according to claim 1, characterized in that, The surface defect detection of the pretreated billet, and the resulting detection results, include: The pretreated billet is flipped using a steel flipping machine so that the upper and lower surfaces of the pretreated billet are inspected sequentially. The upper and lower surfaces are imaged at high resolution using optical image processing technology and compared with a preset defect feature library to output the detection results. The flipping action of the steel turning machine is driven by a motor.

6. The method according to claim 1, characterized in that, Before performing surface defect detection on the pretreated billet, the method further includes: Compressed air is used to remove residual water from the surface of the pretreated billet to optimize the inspection environment of the surface.

7. The method according to claim 1, characterized in that, The preset value is 0.

5.

8. A device for detecting surface defects in cast billets, characterized in that, include: The billet pre-test unit is used to calculate the carbon equivalent of the steel grade in the billet to be tested. The billet processing unit is used to perform water immersion descaling on the billet to be inspected when the carbon equivalent of the steel grade is less than or equal to a preset value, so as to obtain a pretreated billet. The billet inspection unit is used to inspect the surface defects of the pretreated billet and obtain the inspection results.

9. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program stored in the memory to implement the steps of the method for detecting surface defects of a cast billet as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the method for detecting surface defects of the cast billet as described in any one of claims 1 to 7.

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