Method for judging microstructure uniformity of thick-gauge high-strength steel and detection system

Abstract

The application provides a thick-gauge high-strength steel organization uniformity judgment method, and belongs to the technical field of metallurgical hot rolling. The method comprises the following steps: pouring molten steel into a billet, obtaining a strip steel with a thickness of greater than or equal to 20 mm after heating, rolling and cooling; obtaining the turtle back data of the strip steel; if the turtle back is greater than or equal to 25 mm, it is determined that the grains on the lower surface are 0.5 levels or more coarser than those on the upper surface; and if the turtle back is less than 25 mm, it is determined that the grain size difference between the upper and lower surfaces is less than or equal to 0.5 levels. The turtle back data obtained by the laminar flow cooling and the plate shape detector in real time is used to quickly judge the organization uniformity, offline metallographic detection is not needed, online, nondestructive and instant diagnosis is realized, the cooling process can be adjusted in time, and the product quality and production efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical hot rolling technology, specifically relating to a method and detection system for judging the uniformity of microstructure in thick-gauge high-strength steel. Background Technology

[0002] Thick-gauge (h≥20mm) high-strength steel is widely used in engineering machinery, wear-resistant structures, and other fields. The uniformity of its upper and lower surface microstructure directly affects the mechanical properties, internal stress distribution, and subsequent processing stability of the product. Currently, the conventional method for judging the uniformity of the upper and lower surface microstructure of strip steel is as follows: after the strip steel has been produced, a sample is cut, and after sample preparation processes such as mounting, grinding, polishing, and etching, the metallographic structure is observed using an optical microscope to compare the differences in grain size and the content of low-temperature phases (such as bainite B) on the upper and lower surfaces. Although this method is accurate, it has the following drawbacks: it is time-consuming, usually taking several hours or even half a day from sampling to obtaining test results, which cannot meet the needs of rapid feedback from the production line; it is a destructive test, requiring strip steel samples to be cut for each batch, resulting in product waste and increased costs; and it is an offline test, where test results lag behind the production process, and by the time microstructure inhomogeneity is discovered, a large number of defective products have already been produced, making it difficult to adjust cooling process parameters in a timely manner.

[0003] Therefore, there is an urgent need in this field for a technical solution that can determine the uniformity of microstructure on the upper and lower surfaces of thick high-strength steel online, quickly, and non-destructively. Summary of the Invention

[0004] To address the technical problems of relying on offline metallographic testing, which is time-consuming, labor-intensive, and lacks online feedback in commonly used techniques for determining the microstructure uniformity of thick-gauge high-strength steel, this invention provides a method for determining the microstructure uniformity of thick-gauge high-strength steel, comprising the following steps: Molten steel is poured into steel billets; The steel billet is subjected to heat treatment, rolling treatment and cooling treatment in sequence to obtain thick-gauge high-strength steel with a thickness ≥20mm; Obtain the turtle-shell data of the high-strength steel, and determine the tissue uniformity based on the turtle-shell data: If the turtle shell is ≥25mm, then the grains on the lower surface of the high-strength steel are determined to be coarser than those on the upper surface, and the grain size on the lower surface is 0.5 grades or more coarser than that on the upper surface. If the shell thickness is less than 25mm, then the upper and lower surfaces of the high-strength steel are determined to have the same grain size, and the difference between the two grain sizes is ≤0.5.

[0005] Furthermore, the chemical composition of the molten steel, by mass fraction, is as follows: C 0.18-0.26%, Si 0.1-0.3%, Mn 1.0-1.5%, S ≤0.010%, P ≤0.020%, Als 0.025-0.060%, Nb 0.01-0.03%, Ti 0.01-0.03%, Cr 0.2-0.5%, B 0.0010-0.0030%, with the remainder being Fe and unavoidable impurities.

[0006] Furthermore, the thickness of the steel billet is 230-240 mm.

[0007] Furthermore, the billet is heat-treated at a temperature of 1200-1280℃ for a duration of 150-300 min.

[0008] Furthermore, the rolling process includes roughing and finishing rolling, with the finishing rolling exit temperature being 850-900℃.

[0009] Furthermore, obtaining the turtle-shell data of the high-strength steel includes: The strip after laminar flow cooling is inspected using a strip shape detector to detect the protrusions in the width direction of the strip, i.e., the turtle back; The strip shape detector projects onto the width of the strip using a line laser, point laser, or other projection device. The camera accurately captures the shape and position of the projection, and after eliminating interference from vibration and moisture, it converts the data into measurement data. The measurement of the turtle-back shape is then completed through a model algorithm.

[0010] Furthermore, the high-strength steel is coiled to obtain a steel coil, and the coiling temperature is 600-700℃.

[0011] Furthermore, when the turtle shell is ≥25mm, the bainite content on the lower surface of the strip is lower than that on the upper surface.

[0012] Furthermore, this includes: using the method described above to determine the uniformity of the strip's microstructure; When the turtle shell is determined to be ≥25mm, increase the cooling intensity of the lower surface or decrease the cooling intensity of the upper surface until the turtle shell data drops below 25mm; When the turtle shell is determined to be less than 25mm, maintain the current cooling parameters for the upper and lower surfaces.

[0013] This invention provides a detection system for implementing the method for judging the microstructure uniformity of thick-gauge high-strength steel as described above, comprising: The strip shape detector is located after the laminar flow cooling device and before the coiler. It is used to detect protrusions in the width direction of the strip to obtain turtle back data. The strip shape detector includes: at least one line laser or point laser for projecting a beam of light in the width direction of the strip; at least one camera for capturing the shape and position of the projection; and a data processing module for eliminating vibration and moisture interference, converting the captured projection information into measurement data, and calculating the turtle-back data through a model algorithm.

[0014] Compared with the prior art, the present invention has at least the following advantages: This invention utilizes the turtle-back data (protrusion in the width direction) acquired in real time by a plate shape detector after laminar flow cooling to directly determine the uniformity of the microstructure on the upper and lower surfaces of high-strength steel with thick specifications (h≥20mm). It eliminates the need for offline testing steps such as sampling, sample preparation, and metallographic observation, reducing the diagnostic time from several hours to seconds and achieving online real-time feedback on microstructure uniformity.

[0015] This invention acquires turtle-back data through non-contact optical measurement without damaging the strip surface, avoiding product waste caused by cutting samples in traditional metallographic testing and reducing testing costs. Through rapid diagnosis and timely feedback, it effectively avoids the generation of batch-type structural defects, reducing product rework and scrap.

[0016] This invention clarifies the quantitative correspondence between the back-growth data and the differences in grain size and bainite content between the upper and lower surfaces (a back-growth ≥ 25 mm indicates that the grain size of the lower surface is 0.5 grades coarser than that of the upper surface, and the bainite content of the lower surface is lower than that of the upper surface; a back-growth < 25 mm indicates that the grain size of the upper and lower surfaces is consistent, and the difference between the two grain sizes is ≤ 0.5 grades). The production line can adjust the convective cooling intensity of the upper and lower surfaces in real time based on the back-growth data, thereby improving the uniformity of the microstructure, mechanical properties, and internal stress distribution of thick strip steel, and reducing quality defects caused by uneven microstructure.

[0017] This invention can quickly determine the cooling uniformity and the difference in the upper and lower metallographic structures of laminar cooling after rolling by using the back data of high-strength steel with specific chemical composition, and has high practical value. Attached Figure Description

[0018] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a turtle-back matrix diagram formed by the measurement data of the laminar flow cooling detection device in Embodiment 1 of the present invention; Figure 2 This is a metallographic diagram of the upper surface in Embodiment 1 of the present invention; Figure 3 This is a metallographic diagram of the lower surface in Embodiment 1 of the present invention; Figure 4 This is a turtle-back matrix diagram formed by the measurement data of the laminar flow cooling detection device in Embodiment 2 of the present invention; Figure 5 This is a metallographic diagram of the upper surface in Embodiment 2 of the present invention; Figure 6 This is a metallographic diagram of the lower surface in Embodiment 2 of the present invention. Detailed Implementation

[0020] 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 a part of the embodiments of the present invention, and not all of them. 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.

[0021] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0022] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0023] This invention provides a method for determining the microstructure uniformity of thick-gauge high-strength steel, comprising the following steps: Molten steel is poured into steel billets; The steel billet is subjected to heat treatment, rolling treatment and cooling treatment in sequence to obtain thick-gauge high-strength steel with a thickness ≥20mm; Obtain the turtle-shell data of the high-strength steel, and determine the tissue uniformity based on the turtle-shell data: If the turtle shell is ≥25mm, then the grains on the lower surface of the high-strength steel are determined to be coarser than those on the upper surface, and the grain size on the lower surface is 0.5 grades or more coarser than that on the upper surface. If the shell thickness is less than 25mm, then the upper and lower surfaces of the high-strength steel are determined to have the same grain size, and the difference between the two grain sizes is ≤0.5.

[0024] For example, the thickness of the thick-gauge high-strength steel can be 20-30mm or 20-40mm.

[0025] In some embodiments, the chemical composition of the molten steel, by mass fraction, is: C 0.18-0.26%, Si 0.1-0.3%, Mn 1.0-1.5%, S ≤0.010%, P ≤0.020%, Als 0.025-0.060%, Nb 0.01-0.03%, Ti 0.01-0.03%, Cr 0.2-0.5%, B 0.0010-0.0030%, with the remainder being Fe and unavoidable impurities.

[0026] For example, in the chemical composition of the high-strength steel described in this invention, the carbon content can be 0.18%, 0.20%, 0.22%, 0.26%, and any value between the minimum and maximum values ​​mentioned above, or a range consisting of any two values. The silicon content can be 0.1%, 0.20%, 0.3%, or any value within the above range; the manganese content can be 1.0%, 1.2%, 1.4%, 1.5%, or any value between these ranges. The aluminum content (Als) can be 0.025%, 0.035%, 0.045%, 0.055%, 0.060%, or any value in between; The niobium content can be 0.01%, 0.020%, 0.03%, or any value in between; the titanium content can be 0.01%, 0.020%, 0.03%, or any value in between. The chromium content can be 0.2%, 0.30%, 0.40%, 0.5%, or any value in between; The boron content can be 0.0010%, 0.0020%, 0.0030%, or any value in between.

[0027] It should be noted that the turtle-back criterion of this invention is based on thick-gauge high-strength steel within the aforementioned specific chemical composition range, and is derived through extensive production data and metallographic testing verification. Under this chemical composition system, the hardenability of the steel (especially the synergistic effect of B, Cr, and Mn) and phase transformation behavior are sensitive to the difference in cooling rates between the upper and lower surfaces. This results in a significant turtle-back bulge in the thickness direction of the strip due to the phase transformation volume effect and uneven distribution of thermal stress when cooling is uneven. Furthermore, the height of the turtle-back exhibits a stable quantitative relationship with the difference in grain size and bainite content between the upper and lower surfaces (a turtle-back ≥ 25 mm corresponds to a grain size difference > 0.5 grade).

[0028] If the chemical composition deviates from the stated range, for example, if the B content is below 0.0010% or above 0.0030%, or if the Ti content is insufficient and causes B to be fixed by N, the hardenability of the steel will change. The effect of uneven cooling on the microstructure and plate shape will no longer conform to the aforementioned thresholds, and the criterion of 25mm "turtle back" may lead to misjudgment. Therefore, the judgment method of the present invention is based on the stated chemical composition, and the two are inseparable.

[0029] In some embodiments, the thickness of the steel billet is 230-240 mm. When the thickness is less than 230 mm, the compression ratio is insufficient and the core grains are coarse; when the thickness is greater than 240 mm, it is difficult to heat the core and the rolling load increases.

[0030] In some embodiments, the billet heat treatment temperature is 1200-1280℃ and the duration is 150-300 min. When the temperature is below 1200℃ or the time is less than 150 min, the alloying elements are not fully dissolved, and when the temperature is above 1280℃ or the time is longer than 300 min, the austenite grains grow abnormally and the surface is severely oxidized.

[0031] For example, the heating temperature can be 1200℃, 1220℃, 1240℃, 1260℃, 1280℃, or any value therein; the heating time can be 150min, 180min, 210min, 240min, 270min, 300min, or any value therein.

[0032] In some embodiments, the rolling process includes roughing and finishing rolling, wherein the finishing rolling exit temperature is 850-900°C. A finishing rolling exit temperature of 850-900°C results in a mixed-grain structure when the temperature is below 850°C and the austenite grains coarsen, leading to a coarse final microstructure.

[0033] For example, the finishing mill exit temperature can be 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, or any value in between.

[0034] More specifically, the roughing process can have 5 or 7 passes.

[0035] More specifically, the finishing mill can be a 7-stand finishing mill.

[0036] In some embodiments, the cooling process includes ultrafast cooling and laminar flow cooling.

[0037] In some embodiments, obtaining the turtle-back data of the high-strength steel includes: The strip after laminar flow cooling is inspected using a strip shape detector to detect the protrusions in the width direction of the strip, i.e., the turtle back; The strip shape detector projects onto the width of the strip using a line laser, point laser, or other projection device. The camera accurately captures the shape and position of the projection, and after eliminating interference from vibration and moisture, it converts the data into measurement data. The measurement of the turtle-back shape is then completed through a model algorithm.

[0038] In some embodiments, the high-strength steel is coiled to obtain a steel coil, and the coiling temperature is 600-700℃. The coiling temperature is 600-700℃. Below 600℃, too much bainite or martensite is generated, resulting in poor toughness and distortion of the backing data due to phase transformation expansion interference. Above 700℃, the grains coarsen, the strength is insufficient, and the iron oxide scale thickens.

[0039] For example, the winding temperature can be 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, or any value in between.

[0040] In some embodiments, when the turtle shell is ≥25mm, the bainite content on the lower surface of the strip is lower than that on the upper surface.

[0041] In some embodiments, the uniformity of the microstructure of the strip is determined using the method described above; When the back of the turtle is determined to be ≥25mm, adjust the cooling intensity of the lower surface, such as adjusting the opening of the water valve of the lower manifold of the layer cooling system, increasing the water column height of the lower manifold by 10-20cm, or increasing the number of lower manifolds opened by 2-6; or adjust the cooling intensity of the upper surface, such as reducing the number of upper manifolds opened by 2-6, until the back of the turtle is reduced to below 25mm.

[0042] When the turtle shell is determined to be less than 25mm, maintain the current cooling parameters for the upper and lower surfaces.

[0043] Furthermore, based on the inherent correlation between the turtleback data and the cooling uniformity of the upper and lower surfaces disclosed in this invention, the basic principle of this method can be extended to other steel grades. Reliable diagnostic results can be obtained simply by determining the turtleback threshold according to the calibration method of this invention, taking into account the specific chemical composition and process conditions.

[0044] This invention provides a detection system for implementing the method for judging the microstructure uniformity of thick-gauge high-strength steel as described above, comprising: The strip shape detector is located after the laminar flow cooling device and before the coiler. It is used to detect protrusions in the width direction of the strip to obtain turtle back data. The strip shape detector includes: at least one line laser or point laser for projecting a beam of light in the width direction of the strip; at least one camera for capturing the shape and position of the projection; and a data processing module for eliminating vibration and moisture interference, converting the captured projection information into measurement data, and calculating the turtle-back data through a model algorithm.

[0045] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided: Example 1 Hot-rolled steel grade: A572GR50, thickness: 25.4mm, rapid diagnosis of its microstructure uniformity: The molten steel was cast to obtain a billet. The billet with a thickness of 230 mm was heated to 1230℃ for 180 min. The chemical composition of the billet by mass fraction was: C 0.19%, Si 0.15%, Mn 1.1%, S ≤0.010%, P ≤0.020%, Als 0.028%, Nb 0.023%, Ti 0.018%, Cr 0.35%, B 0.0020%, with the remainder being Fe and unavoidable impurities during smelting.

[0046] The steel billet after exiting the furnace is rough rolled in 7 passes to obtain an intermediate billet. The intermediate billet is then finished rolled in 7 stands at an exit temperature of 880℃ to obtain a finished strip. High-strength steel is obtained by ultra-fast cooling and laminar flow cooling of the finished strip; the high-strength steel is then coiled to obtain steel coils at a coiling temperature of 620℃.

[0047] Results: The real-time data of the turtle-back pattern detected by the plate shape detection device after laminar flow cooling are as follows: Figure 1 The turtle-shell pattern is ≤25mm. Diagnosis indicates that the A572GR50 strip steel, 25.4mm thick, produced during that period exhibits uniform metallographic structure on both upper and lower surfaces, with a grain size difference ≤0.5 grade. Sampling, sample preparation, and metallographic analysis verified that the metallographic structure on both upper and lower surfaces is F+P+B with a small amount of grains and a grain size of 11.5 grade. Figure 2 , Figure 3 This indicates that the rapid diagnostic technology was used to make an accurate diagnosis.

[0048] Example 2 Hot-rolled steel grade: S355JR, thickness: 25mm, rapid diagnosis of its microstructure uniformity: The molten steel was cast to obtain a billet. The high-strength steel billet with a thickness of 230mm was heated to 1245℃ for 190 minutes. The chemical composition of the billet by mass fraction was: C 0.25%, Si 0.22%, Mn 1.2%, S ≤0.010%, P ≤0.020%, Als 0.030%, Nb 0.025%, Ti 0.025%, Cr 0.40%, B 0.0025%, with the remainder being Fe and unavoidable impurities during smelting.

[0049] After exiting the furnace, the steel billet is rough rolled in 7 passes to obtain an intermediate billet. The intermediate billet is then finished rolled in 7 stands at an exit temperature of 860℃ to obtain a finished strip. High-strength steel is obtained by ultra-fast cooling and laminar flow cooling of the finished strip; the high-strength steel is then coiled to obtain steel coils at a coiling temperature of 680℃.

[0050] Results: The real-time data of the turtle-back pattern detected by the plate shape detection device after laminar flow cooling are as follows: Figure 4 The back of the steel strip was >25mm, reaching 45mm. Diagnosis indicated that the metallographic structure of the 25mm thick S355JR strip produced during that period was uneven, with a grain size difference >0.5 grade. Sampling, sample preparation, and metallographic analysis verified that the upper surface metallographic structure was F+P+B with a grain size of 11.5 grade, while the lower surface metallographic structure was 10.5 grade with an F+P grain size. Figure 5 , Figure 6 This demonstrates that the rapid diagnostic technique accurately determines the uniformity of the upper and lower metallographic structures.

[0051] Example 3 Hot-rolled steel grade: S355J0, thickness: 23.9mm, rapid diagnosis of its microstructure uniformity: The molten steel was cast to obtain a billet. The billet with a thickness of 230 mm was heated to 1250℃ for 200 min. The chemical composition of the billet by mass fraction was: C 0.20%, Si 0.22%, Mn 1.2%, S ≤0.010%, P ≤0.020%, Als 0.028%, Nb 0.018%, Ti 0.023%, Cr 0.40%, B 0.0025%, with the remainder being Fe and unavoidable impurities during smelting.

[0052] After exiting the furnace, the steel billet is rough rolled in 7 passes to obtain an intermediate billet. The intermediate billet is then finished rolled in 7 stands at an exit temperature of 890℃ to obtain a finished strip. High-strength steel is obtained by ultra-fast cooling and laminar flow cooling of the finished strip; the high-strength steel is then coiled to obtain steel coils at a coiling temperature of 650℃.

[0053] Results: Real-time data of the turtle-back pattern detected by the plate shape detection device after laminar flow cooling showed a turtle-back diameter of 20mm-25mm. This indicated that the S355J0 strip with a thickness of 23.9mm produced during that period exhibited uniform metallographic structure on both the upper and lower surfaces, with a grain size difference ≤0.5. Sampling, sample preparation, and metallographic analysis verified that the metallographic structure on both the upper and lower surfaces was low in F+P+B particles, with a grain size of 10.5. This demonstrates the accuracy of the rapid diagnostic technology used.

[0054] Example 4 Hot-rolled steel grade: Q460C, thickness: 20mm, rapid diagnosis of its microstructure uniformity: The molten steel was cast to obtain a billet. The billet with a thickness of 240 mm was heated to 1240℃ for 260 min. The chemical composition of the billet by mass fraction was: C 0.22%, Si 0.18%, Mn 1.15%, S ≤0.010%, P ≤0.020%, Als 0.038%, Nb 0.028%, Ti 0.015%, Cr 0.45%, B 0.0015%, with the remainder being Fe and unavoidable impurities during smelting.

[0055] After exiting the furnace, the steel billet is rough rolled in 7 passes to obtain an intermediate billet. The intermediate billet is then finished rolled in 7 stands at an exit temperature of 870℃ to obtain a finished strip. High-strength steel is obtained by ultra-fast cooling and laminar flow cooling of the finished strip; the high-strength steel is then coiled to obtain steel coils at a coiling temperature of 660℃.

[0056] Results: Real-time data of the turtle-back pattern detected by the plate shape detection device after laminar flow cooling showed a turtle-back diameter of 15mm to 25mm. This indicated that the metallographic structure of the Q460C strip with a thickness of 20mm produced during that period was uniform on both the upper and lower surfaces, with a grain size difference ≤0.5. Sampling, sample preparation, and metallographic analysis verified that the metallographic structure on both the upper and lower surfaces was low in F+P+B particles, with a grain size of 11.0. This demonstrates the accuracy of the rapid diagnostic technology used.

[0057] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for judging the uniformity of microstructure in thick-gauge high-strength steel, characterized in that, Including the following steps: Molten steel is poured into steel billets; The steel billet is subjected to heat treatment, rolling treatment and cooling treatment in sequence to obtain thick-gauge high-strength steel with a thickness ≥20mm; Obtain the turtle-shell data of the high-strength steel, and determine the tissue uniformity based on the turtle-shell data: If the turtle shell is ≥25mm, then the grains on the lower surface of the high-strength steel are determined to be coarser than those on the upper surface, and the grain size on the lower surface is 0.5 grades or more coarser than that on the upper surface. If the shell thickness is less than 25mm, then the grain size of the upper and lower surfaces of the high-strength steel is determined to be consistent, and the difference in grain size between the upper and lower surfaces is ≤0.

5.

2. The method of judging the microstructure uniformity of a thick-gauge high-strength steel according to claim 1, characterized by, The chemical composition of the molten steel, by mass fraction, is as follows: C 0.18-0.26%, Si 0.1-0.3%, Mn 1.0-1.5%, S ≤0.010%, P≤0.020%, Als 0.025-0.060%, Nb 0.01-0.03%, Ti 0.01-0.03%, Cr 0.2-0.5%, B 0.0010-0.0030%, with the remainder being Fe and unavoidable impurities.

3. The method of judging the microstructure uniformity of a heavy gauge high-strength steel according to claim 1, characterized by, The thickness of the steel billet is 230-240 mm.

4. The method of judging the microstructure uniformity of a heavy gauge high-strength steel according to claim 1, characterized by, The billet is heated at a temperature of 1200-1280℃ for a duration of 150-300 min.

5. The method of judging the microstructure uniformity of a heavy gauge high-strength steel according to claim 1, characterized by, The rolling process includes roughing and finishing, with the finishing temperature at 850-900℃.

6. The method for judging the uniformity of microstructure of thick-gauge high-strength steel according to claim 1, characterized in that, The process of obtaining the turtle-back data of the high-strength steel includes: The strip after laminar flow cooling is inspected using a strip shape detector to detect the protrusions in the width direction of the strip, i.e., the turtle back; The strip shape detector projects onto the width of the strip using a line laser, point laser, or other projection device. The camera accurately captures the shape and position of the projection, and after eliminating interference from vibration and moisture, it converts the data into measurement data. The measurement of the turtle-back shape is then completed through a model algorithm.

7. The method for judging the uniformity of microstructure of thick-gauge high-strength steel according to claim 1, characterized in that, The high-strength steel is coiled to obtain a steel coil, and the coiling temperature is 600-700℃.

8. The method for judging the uniformity of microstructure of thick-gauge high-strength steel according to claim 1, characterized in that, When the turtle shell is ≥25mm, the bainite content on the lower surface of the strip is lower than that on the upper surface.

9. The method for judging the uniformity of microstructure of thick-gauge high-strength steel according to claim 1, characterized in that, The uniformity of the microstructure of the strip steel is determined by the method described in any one of claims 1-8; When the turtle shell is determined to be ≥25mm, increase the cooling intensity of the lower surface or decrease the cooling intensity of the upper surface until the turtle shell data drops below 25mm; When the turtle shell is determined to be less than 25mm, maintain the current cooling parameters for the upper and lower surfaces.

10. A detection system for implementing the method for judging the microstructure uniformity of thick-gauge high-strength steel according to any one of claims 1-7, characterized in that, include: The strip shape detector is located after the laminar flow cooling device and before the coiler. It is used to detect protrusions in the width direction of the strip to obtain turtle back data. The strip shape detector includes: at least one line laser or point laser for projecting a beam of light in the width direction of the strip; at least one camera for capturing the shape and position of the projection; and a data processing module for eliminating vibration and moisture interference, converting the captured projection information into measurement data, and calculating the turtle-back data through a model algorithm.

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