Online width adjustment accurate control method for slab continuous casting machine crystallizer

Abstract

The invention discloses an online width adjustment precise control method for a slab continuous casting machine crystallizer, and belongs to the technical field of steelmaking continuous casting production. According to the method disclosed by the invention, the stable operation of online width adjustment of the crystallizer is realized, the fault occurrence rate is reduced, and the casting blank quality is guaranteed by determining the width adjustment steel grade range, standardizing the equipment inspection process and accurately controlling key process parameters; according to the method, the problems of poor steel type adaptability, inaccurate parameter control and high equipment failure risk in the existing crystallizer online width adjusting technology are solved.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking continuous casting production technology, and particularly relates to a method for precise online width adjustment control of the crystallizer in a slab continuous casting machine. Background Technology

[0002] With the increase in steelmaking capacity and the expansion of steel grades, the demand for small-order contracts is growing. Online width adjustment technology for continuous casting crystallizers has become a key means to increase the number of continuous casting heats, reduce production costs, and improve continuous casting efficiency. Currently, online width adjustment operations in crystallizers suffer from problems such as unclear compatibility with the adjusted steel grades, inaccurate control of adjustment process parameters, and unsystematic equipment status checks. These issues can easily lead to crystallizer alarms, steel jamming, and cold steel residue during width adjustment, affecting not only billet quality but also potentially interrupting the production process and making it difficult to meet the stable production needs of continuous casting.

[0003] In existing technologies, online width adjustment in continuous casting crystallizers often focuses on adjusting single parameters (such as casting speed and width adjustment amount), lacking coordinated control over steel characteristics, equipment status, and process parameters. For example, some processes do not explicitly prohibit width adjustment operations for high-carbon steel and high-strength structural steel, leading to the risk of production stoppage due to horizontal billet handling; the control standards for key parameters such as the corner gap value and slag layer thickness before and after width adjustment are vague, resulting in insufficient width adjustment accuracy; and the lack of specific requirements for slide cleaning and narrow-face movement flexibility in equipment inspection increases the probability of equipment jamming during the width adjustment process. Therefore, developing an online width adjustment method for continuous casting crystallizers that encompasses steel selection, precise parameter control, and equipment status management is of great significance for ensuring stable continuous casting production and improving product quality. Summary of the Invention

[0004] To overcome the problems of poor steel grade compatibility, inaccurate parameter control, and high equipment failure risk in existing online crystallizer width adjustment technologies, the purpose of this invention is to provide a precise control method for online width adjustment of slab continuous casting machine crystallizers. By clarifying the range of steel grades to be adjusted, standardizing equipment inspection procedures, and precisely controlling key process parameters, stable operation of online width adjustment of the crystallizer can be achieved, the failure rate can be reduced, and the quality of the cast billet can be guaranteed.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention provides a method for precise online width adjustment control of the crystallizer in a slab continuous casting machine, comprising:

[0007] (1) Preparations before the adjustment of the steel width and steel grade selection

[0008] 1.1) Steel grade selection: Steel grades that are explicitly prohibited from being widened in casting include high carbon steel, weathering steel, X65M and above grade steel, and BT610L and above grade steel; QStE460TM or BT590CL and above grade structural steel should be widened as much as possible during the mixed casting process;

[0009] 1.2) Casting speed setting: The online width adjustment casting speed of the 2150mm continuous casting machine is controlled at 0.8-1.0m / min, and the online width adjustment casting speed of the 1650mm machine is fixed at 0.8m / min;

[0010] 1.3) Equipment and parameter inspection: After the previous pouring is stopped, check the corner gap value of the wide side of the crystallizer after manual opening before and after the width adjustment, the operation status of the width adjustment function and other process parameters; focus on measuring the corner gap value within 200mm from the top of the crystallizer, and ensure that the sum of the corner gap values ​​of the narrow side and the two wide sides is ≤1.3mm. If it does not meet the requirement, adjust it immediately.

[0011] (2) Inspection of protective and cold steel before width adjustment

[0012] 2.1) Sealing ingot operation: When applying iron sludge to the sealing ingot, do not apply iron sludge within 100mm of the upper edge of the four corner seams of the crystallizer;

[0013] 2.2) Protection and Cold Steel Cleaning: Before pouring, asbestos cloth is laid between the wide and narrow sides of the crystallizer and inside the guide groove for protection; after the widening pouring begins, check whether there is cold steel at the corner of the narrow side and inside the widening slide. If there is cold steel, it must be completely removed. If it cannot be removed, the widening is cancelled; 10 meters before the widening, lift the small cover plate of the narrow side of the crystallizer and check the cold steel residue again.

[0014] (3) Precise control of parameters during the width adjustment process

[0015] 3.1) Liquid slag layer control: 15 minutes before the start-up of the widening process, remove large slag bars from the crystallizer and control the thickness of the liquid slag layer to 8-15 mm; during the widening process, it is strictly forbidden to remove slag bars, and avoid adding powdered slag to the narrow side when adding slag;

[0016] 3.2) Simulated width adjustment and corner gap control: Simulated width adjustment must be performed before hot width adjustment. Check the corner gap value after the width of the cross section is opened before and after the width adjustment. The sum of the two corner gap values ​​on one side should be ≤1.0mm. Test the flexibility of the narrow face movement. If there is any jamming, it needs to be readjusted. The maximum corner gap value after adjustment should not exceed 1.3mm.

[0017] 3.3) Sprue and troubleshooting: During the width adjustment process, the immersion depth of the sprue is controlled according to the centerline; if a steel leakage alarm occurs in the crystallizer or a width adjustment cylinder malfunction alarm occurs, the width adjustment should be stopped immediately and the tail billet should be capped; if a production accident escalates, the billet should be pulled out directly to avoid horizontal billet.

[0018] (4) Post-adjustment inspection and data feedback

[0019] 4.1) Inspection after stopping pouring: After stopping the pouring of the widened pouring, check the steel clamping in the corner of the crystallizer and measure the actual taper value of the narrow face and the upper opening size.

[0020] 4.2) Data feedback: The steel clamping situation at the corner joint, the taper value, and the upper opening dimension value should be reported truthfully and formed into a process record.

[0021] Furthermore, the steel grade for the casting was adjusted to Q235B, and the casting speed was set to 1.0m / min.

[0022] Furthermore, after the previous pouring was stopped, the inner corner gap value of the crystallizer was measured within 200mm of the top opening. The sum of the corner gap values ​​of the narrow side and the wide side was 1.0mm. The width adjustment function was tested and found to be working normally, and there were no debris in the slide.

[0023] Furthermore, the width adjustment process control: 15 minutes before the width adjustment, the large slag strips were removed, and the thickness of the liquid slag layer was 12mm; during the simulated width adjustment, the sum of the corner gap values ​​on one side was 0.9mm, and the narrow face moved flexibly; during the width adjustment process, the immersion depth of the water inlet was controlled according to the centerline, and there were no alarms.

[0024] Furthermore, the steel grade for the widest casting was Q345R, and the casting speed was fixed at 0.8m / min.

[0025] Furthermore, after the previous pouring was stopped, the sum of the corner joint values ​​was measured to be 1.2mm.

[0026] Furthermore, the width adjustment process control is as follows: 15 minutes before the width adjustment, the slag removal bar has a liquid slag layer thickness of 10 mm; the sum of the simulated width adjustment single-sided corner gap values ​​is 0.8 mm, and there is no obstruction on the narrow face; there are no alarms during the width adjustment process, and the immersion depth of the water nozzle meets the centerline requirements.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0028] 1. This invention avoids quality risks from the source by clearly defining the prohibitions on steel grades and the standards for casting speed, and solves the problem of unclear steel grade compatibility in existing processes, thus adapting to the production needs of small orders with multiple steel grades.

[0029] 2. By standardizing equipment inspection, protective installation, and cold steel cleaning processes, the failure rate of the widening equipment has been reduced to below 3.2%, significantly improving production stability and reducing cost waste caused by failures.

[0030] 3. Precise control of parameters such as the liquid slag layer and corner gap value during the width adjustment process reduces the defect rate of steel sandwiched in the billet to 2.1%, ensuring the quality of the billet. At the same time, it does not require modification of existing equipment, is simple to operate, and is suitable for large-scale industrial production. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments.

[0032] Example 1

[0033] A method for precise online width adjustment control of a continuous casting crystallizer, comprising the following steps:

[0034] 1. Steel grade confirmation: The steel grade for this widening casting is Q235B (not a prohibited widening steel grade), and No. 1 casting machine is selected, with the casting speed set to 1.0m / min.

[0035] 2. Pre-adjustment inspection: After the previous pouring is stopped, measure the inner corner gap value of the crystallizer at 200mm from the top. The sum of the corner gap values ​​of the narrow side and the wide side should be 1.0mm (meets the standard); test that the width adjustment function is working normally and that there are no debris in the slide.

[0036] 3. Protection and Cold Steel Inspection: When sealing the ingot, do not apply iron slurry within 100mm of the corner seam from the top edge; lay asbestos cloth before pouring, and check for cold steel residue after pouring; lift the small cover plate 10 meters before width adjustment and confirm again that there is no cold steel.

[0037] 4. Width Adjustment Process Control: 15 minutes before width adjustment, large slag bars are removed, and the liquid slag layer thickness is 12mm; during simulated width adjustment, the sum of the corner gap values ​​on one side is 0.9mm, and the narrow face moves flexibly; during the width adjustment process, the immersion depth of the nozzle is controlled according to the centerline, and there are no alarms.

[0038] 5. Post-width adjustment inspection: After casting is stopped, check that there is no embedded steel in the corner seam, the taper value of the narrow face meets the standard, the upper opening dimension meets the standard, and the data is reported and recorded. Upon inspection, the cast billet has no embedded steel defects and is of qualified quality.

[0039] Example 2

[0040] A method for precise online width adjustment control of a continuous casting crystallizer, comprising the following steps:

[0041] 1. Steel grade confirmation: The steel grade for this widening casting is Q345R (not a prohibited widening steel grade), and No. 2 casting machine is selected, with a fixed casting speed of 0.8m / min.

[0042] 2. Pre-adjustment inspection: After the previous pouring was stopped, the sum of the corner joint values ​​was measured to be 1.2mm (meets the standard); the width adjustment function test was normal, and the equipment was normal.

[0043] 3. Protection and Cold Steel Inspection: The sealing of the ingot operation meets the requirement that no iron slurry should be applied within 100mm of the corner gap; asbestos cloth is laid before pouring, and a small amount of cold steel is found in the narrow corner gap after pouring. After cleaning, it is checked again and no residue is found; it is confirmed that there is no cold steel in the 10 meters before the width adjustment.

[0044] 4. Width Adjustment Process Control: 15 minutes before width adjustment, the slag removal bar is used, and the liquid slag layer thickness is 10mm; the sum of the simulated width adjustment single-sided corner gap values ​​is 0.8mm, and there is no obstruction on the narrow side; there are no alarms during the width adjustment process, and the immersion depth of the water inlet meets the centerline requirements.

[0045] 5. Post-width adjustment inspection: After casting is stopped, there is no steel clamping at the corner joint, the taper value and the upper opening dimension are normal, and the data is reported. The billet quality inspection is qualified and there are no defects.

[0046] Example 3

[0047] A method for precise online width adjustment control of a continuous casting crystallizer, comprising the following steps:

[0048] 1. Steel grade confirmation: The planned steel grade to be widened this time is X70 (belonging to X65M and above, widening is prohibited), which will be replaced with A36 steel grade. Casting machine No. 1 will be used, with a casting speed of 0.9m / min.

[0049] 2. Pre-adjustment inspection: After the previous pouring was stopped, the sum of the initial corner joint values ​​was 1.4mm (not up to standard), and after adjustment it was reduced to 1.2mm; the width adjustment function and other parameters were normal.

[0050] 3. Protection and cold steel inspection: Apply iron mortar to the sealing ingot within 100mm of the corner seam as required; lay asbestos cloth before pouring; check twice, once after pouring and once 10 meters before width adjustment, and find no cold steel.

[0051] 4. Width Adjustment Process Control: 15 minutes before width adjustment, the slag removal bar has a liquid slag layer thickness of 9mm; the sum of the simulated width adjustment single-sided corner gap values ​​is 1.0mm, and the narrow face moves flexibly; there are no fault alarms during the width adjustment process.

[0052] 5. Post-width adjustment inspection: After casting is stopped, there is no steel clamping at the corner seam, the measured parameters are normal and reported. The billet inspection is qualified and meets production requirements.

[0053] Experimental verification and effect analysis

[0054] To verify the effectiveness of the process method of the present invention, comparative experiments were conducted, as follows:

[0055] 1. Experimental Design

[0056] 1) Control group: The conventional width adjustment method was used, with no clear steel grade selection criteria, and the corner gap value control range was loose (≤1.5mm). No special inspection of the cold steel and liquid slag layer was carried out before the width adjustment.

[0057] 2) Experimental group: The method of this invention was adopted, and steel grade selection, corner gap value control (≤1.3mm), cold steel cleaning and liquid slag layer control (8-15mm) were strictly implemented.

[0058] 2. Comparison of Experimental Results

[0059] Test Plan Wide-width fault incidence rate (%) Defect rate of steel sandwiched in cast billet (%) Corner seam value compliance rate (%) control group 18.5 12.3 76.8 experimental group 3.2 2.1 98.5

[0060] The data shows that the failure rate of the width adjustment in the experimental group was reduced by 15.3 percentage points compared with the control group, the defect rate of steel sandwiching in the billet was reduced by 10.2 percentage points, and the compliance rate of corner gap value was increased by 21.7 percentage points, which fully demonstrates that this method can effectively improve the stability of width adjustment and the quality of the billet.

[0061] 3. Process stability verification

[0062] The test group completed 50 width adjustment castings, involving 1650mm casting machines and other models, with width adjustments ranging from 20-200mm (minimum 20mm, maximum 200mm). Among them, 49 castings (98%) consistently met the corner gap value (≤1.3mm); 48 castings (96%) controlled the slag layer thickness within 8-15mm; there were no interruptions in width adjustment due to cold steel residue or equipment jamming, demonstrating good process repeatability and stability.

[0063] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for precise online width adjustment control of the crystallizer in a slab continuous casting machine, characterized in that it includes: (1) Preparations before the adjustment of the steel width and steel grade selection 1.1) Steel grade selection: Steel grades that are explicitly prohibited from being widened in casting include high carbon steel, weathering steel, X65M and above grade steel, and BT610L and above grade steel; QStE460TM or BT590CL and above grade structural steel should be widened as much as possible during the mixed casting process; 1.2) Casting speed setting: The online width adjustment casting speed of the 2150mm continuous casting machine is controlled at 0.8-1.0m / min, and the online width adjustment casting speed of the 1650mm machine is fixed at 0.8m / min; 1.3) Equipment and parameter inspection: After the previous pouring is stopped, check the corner gap value of the wide side of the crystallizer after manual opening before and after the width adjustment, the operation status of the width adjustment function and other process parameters; focus on measuring the corner gap value within 200mm from the top of the crystallizer, and ensure that the sum of the corner gap values ​​of the narrow side and the two wide sides is ≤1.3mm. If it does not meet the requirement, adjust it immediately. (2) Inspection of protective and cold steel before width adjustment 2.1) Sealing ingot operation: When applying iron sludge to the sealing ingot, do not apply iron sludge within 100mm of the upper edge of the four corner seams of the crystallizer; 2.2) Protection and Cold Steel Cleaning: Before pouring, asbestos cloth is laid between the wide and narrow sides of the crystallizer and inside the guide groove for protection; after the widening pouring begins, check whether there is cold steel at the corner of the narrow side and inside the widening slide. If there is cold steel, it must be completely removed. If it cannot be removed, the widening is cancelled; 10 meters before the widening, lift the small cover plate of the narrow side of the crystallizer and check the cold steel residue again. (3) Precise control of parameters during the width adjustment process 3.1) Liquid slag layer control: 15 minutes before the start-up of the widening process, remove large slag bars from the crystallizer and control the thickness of the liquid slag layer to 8-15 mm; during the widening process, it is strictly forbidden to remove slag bars, and avoid adding powdered slag to the narrow side when adding slag; 3.2) Simulated width adjustment and corner gap control: Simulated width adjustment must be performed before hot width adjustment. Check the corner gap value after the width of the cross section is opened before and after the width adjustment. The sum of the two corner gap values ​​on one side should be ≤1.0mm. Test the flexibility of the narrow face movement. If there is any jamming, it needs to be readjusted. The maximum corner gap value after adjustment should not exceed 1.3mm. 3.3) Sprue and troubleshooting: During the width adjustment process, the immersion depth of the sprue is controlled according to the centerline; if a steel leakage alarm occurs in the crystallizer or a width adjustment cylinder malfunction alarm occurs, the width adjustment should be stopped immediately and the tail billet should be capped; if a production accident escalates, the billet should be pulled out directly to avoid horizontal billet. (4) Post-adjustment inspection and data feedback 4.1) Inspection after stopping pouring: After stopping the pouring of the widened pouring, check the steel clamping in the corner of the crystallizer and measure the actual taper value of the narrow face and the upper opening size. 4.2) Data feedback: The steel clamping situation at the corner joint, the taper value, and the upper opening dimension value should be reported truthfully and formed into a process record.

2. The method for precise online width adjustment of the crystallizer in a slab continuous casting machine according to claim 1, characterized in that: The steel grade for the widening casting is Q235B, and the casting speed is set to 1.0m / min.

3. The method for precise online width adjustment control of the slab continuous casting machine crystallizer according to claim 2, characterized in that: After the pouring was stopped, the inner corner gap value of the crystallizer was measured 200mm from the top. The sum of the corner gap values ​​of the narrow side and the wide side was 1.0mm. The width adjustment function was tested and found to be working normally, and there were no debris in the slide.

4. The method for precise online width adjustment control of the slab continuous casting machine crystallizer according to claim 3, characterized in that: Width adjustment process control: 15 minutes before width adjustment, large slag bars are removed, and the liquid slag layer thickness is 12mm; during simulated width adjustment, the sum of the corner gap values ​​on one side is 0.9mm, and the narrow face moves flexibly; during the width adjustment process, the immersion depth of the nozzle is controlled according to the centerline, and there are no alarms.

5. The method for precise online width adjustment control of the slab continuous casting machine crystallizer according to claim 1, characterized in that: The steel grade for the widened casting is Q345R, and the casting speed is fixed at 0.8m / min.

6. The method for precise online width adjustment of the slab continuous casting machine crystallizer according to claim 5, characterized in that: After the previous pouring was stopped, the sum of the corner joint values ​​was measured to be 1.2mm.

7. The method for precise online width adjustment control of the slab continuous casting machine crystallizer according to claim 5, characterized in that: Widening process control: 15 minutes before widening, the slag removal bar is used, and the liquid slag layer thickness is 10mm; the sum of the simulated widening single-sided corner gap values ​​is 0.8mm, and there is no obstruction on the narrow side; there are no alarms during the widening process, and the immersion depth of the water inlet meets the centerline requirements.