Paint film visualization efficient evaluation method for uniformity of collecting pipe of ultra-fast cooling equipment

Abstract

The invention discloses a paint film visualization efficient evaluation method for uniformity of a collecting pipe of ultra-fast cooling equipment, and relates to the technical field of cooling after rolling of ferrous metallurgy, and the method comprises the following steps: preparing tracing paint according to characteristics of a production line, adopting a combined system of anti-rust primer and high-developing finish paint, and adjusting to constructable viscosity through a diluent; a low-carbon steel plate made of the same material as a production line is selected and subjected to surface cleaning treatment, then a two-way roll coating process is carried out, roll coating is carried out in the width direction to form a base film, then vertical cross roll coating is carried out to achieve leveling, the thickness of a wet film is accurately controlled, and drying and curing are carried out; a dynamic-static coupling mode is adopted; placing the steel plate on a transport carrier, driving the steel plate to pass through a header spraying area at a target speed through a roller way, then staying and receiving static spraying, and circularly executing for multiple times to strengthen defect characterization; paint film surface trace distribution is analyzed, and a corresponding nozzle is positioned and dredged in a local density abnormal area; and when the overall non-uniformity exceeds a preset threshold value, triggering a header replacement decision.

Description

Technical Field

[0001] This invention relates to the field of post-rolling cooling technology in steel metallurgy, and in particular to a method for visually evaluating the uniformity of paint film in the manifold of ultra-fast cooling equipment. By simulating actual working conditions through paint coating and roller operation, a highly efficient and low-cost uniformity diagnosis can be achieved. Background Technology

[0002] In the production of hot-rolled strip steel, ultra-fast cooling (UFC) equipment is the core equipment for regulating the microstructure and properties of the rolled product. The uniformity of the water flow impact in its manifold directly determines the uniformity of cooling of the steel plate and the consistency of the plate shape, mechanical properties and residual stress distribution after cooling.

[0003] If the water flow distribution in the manifold is uneven due to nozzle blockage, corrosion, or misalignment, the following problems will occur: 1) Local overcooling or insufficient cooling of the steel plate will cause deformation such as warping and waviness; 2) Uneven distribution of phase transformation structures (such as ferrite / pearlite / bainite / martensite) will affect the matching of strength and toughness; 3) Residual stress accumulated due to uneven cooling may cause deformation in batch processing by users.

[0004] Currently, the industry's manifold uniformity detection technology suffers from problems such as complex operation, high cost, or insufficient accuracy. It is mainly divided into three categories: 1) Contact physical measurement method, such as thermocouple array temperature measurement and segmented water collection tank flow statistics; 2) Equipment parameter indirect estimation method, such as calculating flow distribution based on the main pipe flow meter reading and nozzle theoretical parameters; 3) Numerical simulation analysis method, such as CFD fluid dynamics simulation of the water flow field inside the manifold.

[0005] However, the above three methods suffer from problems such as unintuitive test results, low accuracy, high implementation costs, long downtime, and poor adaptability to operating conditions. Therefore, there is an urgent need to develop an ultrafast cooling uniformity testing method that provides intuitive test results, high accuracy, low implementation costs, short testing time, and high adaptability to operating conditions. Summary of the Invention

[0006] To address the aforementioned technical issues, this technical solution provides a visual and efficient evaluation method for the uniformity of the coating film in the manifolds of ultra-fast cooling equipment. This solution resolves the problems of insufficient implicit feature extraction capability and difficulty in multi-source data fusion.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A highly efficient method for visually evaluating the coating uniformity of manifolds in ultra-fast cooling equipment includes:

[0009] S1. Preparation of tracer paint: Based on the steel plate material, usage environment and coating performance requirements of the production line corresponding to the manifold to be tested, select a combination of anti-rust primer and topcoat, and add matching thinner to adjust the viscosity of the paint to a viscosity suitable for roller application.

[0010] S2. Treatment of the test steel plate:

[0011] (a) Select a low-carbon steel plate with the same material as the production line, the thickness of which meets the preset thickness range, and the length L meets the requirements: the length of a single set of headers < L < the available length of the conveying roller table, and the width W > the width of a single set of headers;

[0012] (b) Perform sandblasting or chemical cleaning on the surface of the steel plate to remove oil stains, rust and dust;

[0013] (c) Apply the tracer paint by the two-way roller coating method: the first pass is roller-coated along the width direction of the steel plate at a fixed linear speed; the second pass is roller-coated vertically and crosswise along the length direction of the steel plate at a fixed linear speed; control the wet film thickness and allow it to dry naturally for a fixed time;

[0014] S3. Dynamic-static combined test:

[0015] (a) Place the painted steel plate on the transport plate and convey it under the headers of the ultra-fast cooling equipment;

[0016] (b) Start the roller table to drive the steel plate to pass under the headers at the target speed to complete the dynamic test;

[0017] (c) Stop the roller table to make the steel plate stay under the headers for a set time to complete the static test;

[0018] (d) Repeat steps (b) and (c) 4 to 6 times;

[0019] S4. Result evaluation and decision-making:

[0020] (a) Analyze the distribution density and morphology of the impact marks on the paint film on the surface of the steel plate;

[0021] (b) If the deviation of the trace density in the local area is greater than or equal to the established ratio, dredge the corresponding header nozzles;

[0022] (c) If the overall trace unevenness is greater than or equal to the established ratio, replace the entire set of headers.

[0023] Preferably, the S2 specifically includes:

[0024] Steel plate selection: Select a low-carbon steel plate with the same material as the production line (thickness 10 - 30 mm), and the length and width requirements of the steel plate are: 20 mm ≤ steel plate thickness ≤ 30 mm, the length of a single set of headers < steel plate length < the length of the conveying roller table, and the steel plate width > the width of a single set of headers.

[0025] Preferably, the S2 specifically includes:

[0026] Steel plate pretreatment: Use a cloth dipped in alcohol to clean the surface of the steel plate to be painted, ensure that the surface of the steel plate is smooth, and place it on a stable and clean workbench or bracket.

[0027] Preferably, S2 specifically includes:

[0028] For coating the steel plate surface, start from one edge of the steel plate to be coated, press the roller brush dipped in the coating material onto the steel plate surface with moderate force, and roll the roller brush along the width of the steel plate with a smooth and continuous motion.

[0029] Preferably, S2 specifically includes:

[0030] Steel plate surface coating: The linear speed of the roller movement is controlled at about 1 m / s. After the initial coating of the entire area is completed, a flattening operation is performed with a light force at about 0.7 m / s along the direction perpendicular to the first coating (the length of the steel plate).

[0031] Preferably, S2 specifically includes:

[0032] After completing the initial coating of an area (at which point the coating may be uneven and have roller marks), use a light touch and a slow speed (about 0.5-0.8 m / s) to spread the coating along the direction perpendicular to the first coating (the length of the steel plate).

[0033] Preferably, S2 specifically includes:

[0034] The coating thickness is controlled by comprehensively adjusting the paint viscosity, roller type, roller coating pressure, and speed, so that the single-pass wet film thickness is controlled within the range of 60 to 120 μm.

[0035] Preferably, S4 specifically includes:

[0036] Drying time control: The drying time after coating is completed is 30 to 60 seconds.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] This invention is mainly applied to the evaluation of the uniformity of the manifold in the ultra-fast cooling equipment of medium and heavy plate hot rolling process. The test results are intuitive, highly accurate, low in implementation cost, short in testing time, and highly adaptable to working conditions. It is used to improve the cooling uniformity of ultra-fast cooling equipment, thereby improving the control of the microstructure of steel plates, reducing the overall plate temperature difference upon reheating, and improving the first-pass yield of cooled steel plates. Attached Figure Description

[0039] Figure 1 A flowchart for a visual and efficient evaluation method of paint film uniformity in manifolds of ultrafast cooling equipment;

[0040] Figure 2 To coat the steel plate with paint;

[0041] Figure 3 For transporting pallets;

[0042] Figure 4 This is a schematic diagram of a cooling manifold test.

[0043] Figure 5 For dynamic impact testing of the old manhole cover;

[0044] Figure 6 For dynamic strike testing of the new collection and management system;

[0045] Figure 7 Static impact test for old manifold;

[0046] Figure 8 This is a static impact test for the central pipeline. Detailed Implementation

[0047] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0048] Reference Figure 1 As shown, a visual and efficient evaluation method for the uniformity of paint film in the manifolds of ultra-fast cooling equipment includes:

[0049] S1, Preparation of tracer paint

[0050] Select the appropriate coating (such as anti-rust primer, topcoat, etc.) based on the steel plate material, usage environment, and coating requirements. Pour the coating into a shallow, wide coating tray and adjust the viscosity using the provided thinner.

[0051] S2. Steel plate selection, pretreatment, and coating:

[0052] (a) Steel plate selection: Select low carbon steel plates (thickness 10-30mm) of the same material as the production line. The length and width requirements of the steel plates are: 20mm≤steel plate thickness≤30mm, the length of a single set of manifolds < the length of the steel plate < the length of the conveyor roller, and the width of the steel plate > the width of a single set of manifolds.

[0053] (b) Steel plate pretreatment: Clean the surface of the steel plate to be coated to remove oil, rust, dust and other impurities. Place the steel plate horizontally on a stable and clean workbench or support to ensure that the steel plate does not shake.

[0054] (c) Steel Plate Surface Coating: Starting from one edge of the steel plate to be coated, press the coated roller brush onto the steel plate surface with moderate pressure, rolling the roller brush smoothly and continuously along the width of the steel plate. The linear speed of the roller movement should be controlled at 0.8–1.2 m / s. After completing the initial coating of an area (at this point, the coating may be uneven and have roller marks), use lighter pressure and a slower speed (approximately 0.5–0.8 m / s) to spread the coating along the direction perpendicular to the first coating (usually the length of the steel plate). This step aims to eliminate roller marks and air bubbles, resulting in a more uniform coating and better leveling. Figure 2 As shown;

[0055] (d) Coating thickness and drying time control: By comprehensively controlling the coating viscosity, roller type, roller coating pressure and speed, the single-pass wet film thickness is controlled within the range of 60 to 120 μm, and the drying time after coating is 30 to 60 seconds;

[0056] S3. Test Procedures and Result Evaluation:

[0057] (a) Place the coated steel sheet on the transport board as follows Figure 3 As shown, the transport plate is placed on the transport roller conveyor. The roller conveyor passes through and stops at a single set of manifolds at the target speed (stopping is for static testing, passing through is for dynamic testing). The target manifold flow rate is preset. After passing through 4-6 times, the test steel plate is transported out of the ultra-fast cooling equipment. Figure 4 As shown;

[0058] (b) Record the impact test results on the steel plate surface and evaluate the overall uniformity of the nozzle based on the results. If the local uniformity is poor, clear the blockage at the target location. If the overall uniformity deteriorates significantly, the manifold needs to be replaced.

[0059] S4. Results Evaluation and Decision-Making:

[0060] (a) Analyze the distribution density and morphology of impact marks on the paint film on the steel plate surface;

[0061] (b) If the local area trace density deviation is greater than or equal to a predetermined ratio, the corresponding manifold nozzle shall be cleared.

[0062] (c) If the overall unevenness of the traces is greater than or equal to the predetermined proportion, then replace the entire manifold.

[0063] To make the above-mentioned objects, features and advantages of the present invention more readily understood, the present invention will be further described in detail with reference to the following examples.

[0064] Step 1: Steel plate selection: Select 4 low carbon alloy steel plates of material Q355B. Steel plate dimensions: thickness 15mm, width 1000mm and length 3000mm;

[0065] Step 2: Steel Plate Pretreatment: Clean the surface of the steel plate to be coated using a cloth dampened with alcohol to ensure a smooth surface. Place the plate on a stable, clean workbench or stand.

[0066] Step 3: Coating the steel plate surface: Pour the anti-rust primer into the paint tray and adjust the paint viscosity using the matching thinner. Starting from one edge of the steel plate to be coated, press the paint-soaked roller brush onto the steel plate surface with medium pressure. Roll the roller brush smoothly and continuously along the width of the steel plate, controlling the roller movement speed to about 1 meter / second. After completing the initial coating of the entire area, use lighter pressure and a speed of about 0.7 meters / second to spread the coating evenly along the direction perpendicular to the first coating (the length of the steel plate).

[0067] Step 4: Coating thickness and drying time control: By comprehensively controlling the paint viscosity, roller type, roller coating pressure and speed, the single-pass wet film thickness is controlled at about 100μm, and the drying time after coating is 40 seconds;

[0068] Step 5: Place the coated steel plate on a transport plate, then place the transport plate on a transport roller conveyor. The roller conveyor passes through a single set of old manifolds at a speed of 0.5 m / s, with a manifold flow rate of 100 m³ / h. After passing through this conveyor 6 times (test time 3 seconds), the test steel plate is removed from the ultra-fast cooling equipment, placed on a test bench, and the results are as follows. Figure 5 As shown;

[0069] Step 6: Select the second steel plate and perform pretreatment and testing on the new manifold according to steps 2-5. The results are as follows: Figure 6 As shown;

[0070] Step 7: Select the third steel plate, pre-treat the single new manifold according to steps 2-4, then place it under the single new manifold for static testing with an impact time of 3 seconds. Then, remove the test steel plate from the ultra-fast cooling equipment, remove it, and place it on the test bench. The results are as follows... Figure 8 As shown;

[0071] Step 8: Select the 4th steel plate and pre-treat and test the single set of old manifolds according to steps 2-4 and 7. The results are as follows. Figure 7 As shown;

[0072] Step 9: Place the four steel plates together for comparison.

[0073] Test results: The new manifold exhibited uniform striping during dynamic impact testing, with the static impact spacing matching the nozzle spacing. The old manifold showed significant unevenness during dynamic impact testing. In response, the pickling cycle for the ultra-fast cooling manifold was changed from annual to ten-day maintenance, with phased replacement and targeted unclogging. By performing this test during each ten-day inspection, the uniformity of ultra-fast cooling was improved, and the first-pass yield of cooled steel plates increased from 98.16% to 98.63%. The uniformity of the overall red-hot temperature of 420 grade steel below 600℃ was reduced from 90℃ to 50℃.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for visually evaluating the uniformity of paint film in the manifolds of ultra-fast cooling equipment, characterized in that, It includes: S1. Preparation of tracer paint: According to the steel plate material, usage environment and coating performance requirements of the corresponding production line of the to-be-tested header, select a combined coating of anti-rust primer and topcoat, and add a supporting thinner to adjust the coating viscosity to the viscosity suitable for roller coating construction. S2. Treatment of test steel plate: (a) Select low-carbon steel plates of the same material as the production line, with the thickness meeting the preset thickness range, and the length L meeting the requirement: the length of a single group of headers < L < the available length of the transport roller table, and the width W > the width of a single group of headers. (b) Conduct sandblasting or chemical cleaning treatment on the steel plate surface to remove oil stains, rust and dust. (c) Apply tracer paint using the two-way roller coating method: The first pass is roller-coated along the width direction of the steel plate at a set linear speed; the second pass is roller-coated vertically and crosswise along the length direction of the steel plate at a set linear speed; control the wet film thickness and allow natural drying for a set time. S3. Dynamic-static combined test: (a) Place the painted steel plate on the transport plate and convey it under the headers of the ultra-fast cooling equipment. (b) Start the roller table to drive the steel plate to pass under the headers at the target speed to complete the dynamic test. (c) Stop the roller table to make the steel plate stay under the headers for a set time to complete the static test. (d) Repeat steps (b) and (c) 4 - 6 times. S4. Result evaluation and decision-making: (a) Analyze the distribution density and morphology of the impact marks on the paint film surface of the steel plate. (b) If the deviation of the trace density in a local area is greater than or equal to a set ratio, dredge the corresponding header nozzles. (c) If the overall trace unevenness is greater than or equal to a set ratio, replace the entire set of headers.

2. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 1, characterized in that, The specific content of S2 includes: Steel plate selection: Select low-carbon steel plates of the same material as the production line (with a thickness of 10 - 30 mm), and the length and width requirements of the steel plate are: 20 mm ≤ steel plate thickness ≤ 30 mm, the length of a single group of headers < steel plate length < the length of the transport roller table, and the steel plate width > the width of a single group of headers.

3. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 1, characterized in that, The specific content of S2 includes: Steel plate pretreatment: Use a cloth dipped in alcohol to clean the surface of the to-be-coated steel plate to ensure the steel plate surface is smooth, and place it on a stable and clean workbench or bracket.

4. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 2, characterized in that, The specific content of S2 includes: Coating on the steel plate surface: Starting from one edge of the painting surface of the steel plate, press the roller brush dipped with the material on the steel plate surface with medium force, and roll the roller brush along the width direction of the steel plate with a steady and continuous movement.

5. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 2, characterized in that, The specific content of S2 includes: Coating on the steel plate surface: Control the linear speed of the roller movement at about 1 m / s. After completing the initial coating of the entire area for the first time, use a lighter force to level it at about 0.7 m / s along the direction perpendicular to the first coating direction (the length direction of the steel plate).

6. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 3, characterized in that, The specific content of S2 includes: After completing the initial coating of an area (at this time, the coating may be uneven and have roller marks), use a lighter force and a slower speed (about 0.5 - 0.8 m / s) to level it along the direction perpendicular to the first coating direction (the length direction of the steel plate).

7. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 3, characterized in that, The specific content of S2 includes: Coating thickness: Comprehensively control through coating viscosity, roller type, roller coating pressure and speed, and control the single-pass wet film thickness within the range of 60 - 120 μm.

8. The method for visually evaluating the uniformity of the coating film in the manifold of an ultra-fast cooling device according to claim 4, characterized in that, The specific content of S4 includes: Control of drying time: The drying time after painting is 30 - 60 seconds.

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