An on-line diagnosis method for a slab caster mold

Abstract

This invention belongs to the field of steelmaking continuous casting technology, and relates to an online diagnostic method for the crystallizer of a slab continuous casting machine. The method involves inspecting and measuring the crystallizer body during the casting interval. The diagnostic criteria are as follows: the corner gap of the crystallizer copper plate ≤ 0.3mm; the absolute value of the difference between the length of one side of the inner and outer arcs of the crystallizer copper plate and the standard length of one side of the inner and outer arcs of the crystallizer copper plate ≤ 1mm; the absolute value of the relative thickness difference between the inner and outer arcs and the left and right sides of the crystallizer copper plate ≤ 3mm; the wear value of the narrow face of the crystallizer copper plate ≤ 1mm; the straightness of the crystallizer copper plate ≤ 0.5mm; within 450mm of the top edge along the length direction of the crystallizer copper plate, each crack or scratch must be ≤ 3.0mm wide, ≤ 10mm long, and ≤ 0.5mm deep, with a number of cracks or scratches ≤ 2; outside this area, each crack or scratch must be ≤ 3.0mm wide, ≤ 50mm long, and ≤ 0.5mm deep, with a number of cracks or scratches ≤ 2; and the area of ​​plating cracks at the meniscus ≤ 30×30mm. 2 If the area of ​​coating peeling off at the meniscus is 0, it meets the diagnostic criteria and is considered qualified; otherwise, it is considered unqualified.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking continuous casting technology and relates to an online diagnostic method for slab continuous casting machine crystallizers. Background Technology

[0002] Continuous casting is a manufacturing process in which metal is melted into a liquid, poured into a cooling system, and then pulled out from the other end of the cooling system to form a casting of a specific length and shape. This is a mainstream method for steel forming. The equipment used in this manufacturing process is called continuous casting equipment or a continuous casting machine. The main equipment for continuous steel casting technology includes: a ladle, a ladle turret, an tundish, a crystallizer, a secondary cooling and guiding device, a crystallizer vibration device, a straightening machine, an ingot storage device, a cutting device, and a billet transport device.

[0003] The crystallizer in a slab continuous casting machine is a continuous casting device that receives molten steel poured from the tundish and solidifies it into a solid slab shell according to a specified cross-sectional shape. It is the most critical component of the continuous casting machine, and its structure, material, and performance parameters play a decisive role in the quality of the cast slab and the production capacity of the casting machine. Therefore, diagnosing the quality of the crystallizer is crucial during the slab continuous casting process, as it directly determines the product quality. Using a crystallizer that does not meet quality requirements for slab continuous casting will lead to product quality problems, production accidents, and other adverse effects, and in severe cases, even production interruption.

[0004] However, in existing continuous casting technology, due to the lack of online diagnostic methods for the crystallizer, it is typically disassembled and taken offline for maintenance after completing a specified throughput, based on the crystallizer's specifications and actual on-site construction needs. A new crystallizer is then installed for subsequent slab continuous casting. This method often results in replacement of the crystallizer even when its quality still meets the requirements of the slab continuous casting machine, leading to wasted production resources. Furthermore, because the structure of the slab continuous casting machine is complex, and the crystallizer is closely connected to the slab continuous casting production line, each crystallizer replacement requires a significant amount of time, slowing down the production pace and hindering stable and smooth production. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an online diagnostic method for the crystallizer of a slab continuous casting machine, which performs online diagnostics on the crystallizer during the casting interval and provides a basis for judging whether the quality of the crystallizer meets the requirements for use of the slab continuous casting machine, so as to determine a reasonable crystallizer treatment method, avoid waste of production resources, and ensure stable and smooth production.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for online diagnosis of a slab continuous casting machine crystallizer, which involves inspecting and measuring the crystallizer body during the casting interval, specifically includes the following steps:

[0008] S1. Measure the gap at the corner of the copper plate of the crystallizer, the length of one side of the inner and outer arc of the copper plate of the crystallizer, the thickness of the inner and outer arc and the left and right sides of the copper plate of the crystallizer, the wear value of the narrow surface of the copper plate of the crystallizer, and the flatness of the copper plate of the crystallizer. Also, check the cracks or scratches and the plating of the copper plate of the crystallizer.

[0009] S2. Based on the inspection and measurement results of the crystallizer body in step S1, perform online diagnosis of the crystallizer. The diagnostic criteria are as follows: the corner gap of the crystallizer copper plate ≤ 0.3 mm; the absolute value of the difference between the length of one side of the inner and outer arcs of the crystallizer copper plate and the standard length of one side of the inner and outer arcs of the crystallizer copper plate ≤ 1 mm; the absolute value of the relative thickness difference between the inner and outer arcs and the left and right sides of the crystallizer copper plate ≤ 3 mm; the wear value of the narrow surface of the crystallizer copper plate ≤ 1 mm; and the straightness of the crystallizer copper plate ≤ 0.5 mm. For the copper plate of the crystallizer, within 450mm of the top opening along its length, each crack or scratch must be ≤3.0mm wide, ≤10mm long, and ≤0.5mm deep, with a minimum of 2 cracks or scratches. For the copper plate of the crystallizer, beyond 450mm of the top opening along its length, each crack or scratch must be ≤3.0mm wide, ≤50mm long, and ≤0.5mm deep, with a minimum of 2 cracks or scratches. The area of ​​plating cracks at the meniscus of the copper plate of the crystallizer must be ≤30×30mm. 2 The area of ​​plating peeling off at the meniscus of the copper plate in the crystallizer is 0.

[0010] If the results of the inspection and measurement of the crystallizer body in step S1 meet the diagnostic criteria, the crystallizer is diagnosed as qualified; if the results of the inspection and measurement of the crystallizer body in step S1 do not meet the diagnostic criteria, the crystallizer is diagnosed as unqualified.

[0011] Furthermore, before inspecting and measuring the crystallizer body, the crystallizer width adjustment operating system is set to "local manual" mode, and the crystallizer width adjustment operating system is operated to loosen the wide edge of the crystallizer. Then, the gaps in the crystallizer width adjustment guide groove and the corner of the crystallizer copper plate are cleaned. After cleaning, the crystallizer width adjustment operating system is operated again to clamp the wide edge of the crystallizer.

[0012] Furthermore, it also includes step S3;

[0013] S3: Open the nozzle in the water spray system at the crystallizer outlet, and set the nozzle valve opening to 25%. Then, check whether the S2 diagnosis is correct by observing whether the spray water from the nozzle is directly sprayed onto the roller surface of the foot roller at the crystallizer outlet. If the S2 diagnosis indicates that the crystallizer is qualified, the spray water will not be directly sprayed onto the roller surface of the foot roller at the crystallizer outlet.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention provides an online diagnostic method for the crystallizer of a slab continuous casting machine. The method involves inspecting and measuring the crystallizer body during the casting interval, and clearly defines the inspection and measurement items and diagnostic standards. This allows for online diagnosis of whether the crystallizer quality meets the requirements of the continuous casting machine, thereby reducing production risks caused by crystallizer quality, ensuring slab quality, avoiding the waste of production resources caused by replacing the crystallizer when its quality still meets the requirements of the slab continuous casting machine, and reducing production delays caused by unnecessary crystallizer replacements, thus ensuring smooth production.

[0016] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] An online diagnostic method for the crystallizer of a slab continuous casting machine specifically includes the following steps:

[0019] 1. Prepare tools for crystallizer inspection, including feeler gauges, vernier calipers, and taper gauges, etc.

[0020] 2. After the slab continuous casting machine has completed its casting interval or after the final casting, use a taper meter to measure the taper of the crystallizer and report it to the main control record to make a preliminary judgment on whether the crystallizer needs to be replaced. If the taper of the crystallizer is found to be inconsistent with the standard for use at this time, no further measurement of the crystallizer body is required, and the crystallizer only needs to be replaced immediately. It should be noted that the crystallizer cover plate can only be put on for operation after the tail billet tracking value is greater than 6m, that is, after the tail billet exits the straightening machine (i.e., section 4 in the conventional continuous casting machine).

[0021] 3. Crystallizer cleaning

[0022] Select the crystallizer width adjustment operating system to "local manual" mode, loosen the clamping device on the wide side of the crystallizer, and clean the gaps at the corners of the crystallizer width adjustment guide groove and the copper plate of the crystallizer with compressed air and water. After cleaning, use compressed air to dry the crystallizer cover plate and surrounding area. Operate the crystallizer width adjustment operating system to clamp the wide side of the crystallizer and notify the main controller. Note that you must confirm that there is no steel stuck in the corner gap before opening the wide side of the crystallizer to avoid damaging the crystallizer.

[0023] 4. Vibration inspection:

[0024] Adjust the slab continuous casting machine to "maintenance" mode, then start the crystallizer vibration and observe whether the crystallizer vibrates smoothly, whether there is any abnormal noise, interference, or polarization. If the crystallizer vibrates smoothly, without abnormal noise, interference, or polarization, it is qualified. If the above problems exist, there may be loose connections, and the crystallizer needs to be maintained.

[0025] The key to this embodiment lies in step 5, crystallizer body inspection:

[0026] 51. Re-determine the corner gaps and width adjustment guide grooves of the crystallizer copper plates to ensure that there are no foreign objects or cold steel in the corner gaps and width adjustment guide grooves. Then, use a feeler gauge to measure the gaps at the corners of the crystallizer copper plates. The value of the corner gap is when the feeler gauge is inserted into the gap to a depth of more than 5mm. The measurement range is within 500mm from the top of the crystallizer. The diagnostic standard is that the corner gap value is less than 0.3mm.

[0027] 52. Inspect the copper plate of the crystallizer for cracks, dents, scratches, and peeling of the plating. Check if the pressure strip is properly sealed. Measure the following parameters. The copper plate of the crystallizer must meet the following standard requirements:

[0028] The following requirements apply: The length of the inner and outer arcs of the crystallizer copper plate on one side must be ≤1mm from the standard length of the inner and outer arcs on one side; the relative thickness difference between the inner and outer arcs and the left and right sides of the crystallizer copper plate must be ≤3mm; wear on the narrow face of the crystallizer copper plate must be ≤1mm; the straightness (or curvature) of the crystallizer copper plate must be ≤0.5mm; cracks (or scratches) on the upper part of the crystallizer copper plate, within 450mm of the top edge in the length direction, must be ≤3.0mm wide, ≤10mm long, ≤0.5mm deep, and ≤2 in number; cracks (or scratches) on the lower part of the crystallizer copper plate, beyond 450mm of the top edge in the length direction, must be ≤3.0mm wide, ≤50mm long, ≤0.5mm deep, and ≤2 in number; large-area cracking of the plating at the meniscus of the crystallizer copper plate, with an area ≤30×30mm. 2 The plating on the copper plate of the crystallizer has peeled off at the meniscus, with an area of ​​0.

[0029] If the results of the inspection and measurement of the crystallizer body meet the diagnostic criteria, the crystallizer is diagnosed as qualified; if the results of the inspection and measurement of the crystallizer body do not meet the diagnostic criteria, the crystallizer is diagnosed as unqualified.

[0030] 53. Use a taper meter to re-measure the taper of one side of the crystallizer and fill in the taper record sheet to further ensure that the taper of the crystallizer meets the usage requirements of the continuous casting machine;

[0031] 54. Inspection of foot rollers and nozzles:

[0032] The central control unit is instructed to open the nozzles in the water spray system at the crystallizer outlet (usually the Zone 1 water valve in the continuous casting machine), with the nozzle valve opening at 25%. The nozzle spray pattern is confirmed to be intact and unobstructed, with normal flow and pressure. The foot rollers at the crystallizer outlet are also confirmed to be free of wear, residual cold steel, and foreign matter, rotating normally, and the foot roller support frame is free of displacement or deformation. Further confirmation of the crystallizer's quality is achieved by determining whether the spray water is directly hitting the foot roller surface. If the crystallizer is qualified, the spray water will not directly hit the foot roller surface, thus further confirming that the crystallizer meets the requirements for use in a slab continuous casting machine and avoiding misjudgment.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for online diagnosis of the crystallizer in a slab continuous casting machine, characterized in that, The crystallizer body is inspected and measured during the pouring interval, specifically including the following steps: S1. Measure the gap at the corner of the copper plate of the crystallizer, the length of one side of the inner and outer arc of the copper plate of the crystallizer, the thickness of the inner and outer arc and the left and right sides of the copper plate of the crystallizer, the wear value of the narrow surface of the copper plate of the crystallizer, and the flatness of the copper plate of the crystallizer. Also, check the cracks or scratches and the plating of the copper plate of the crystallizer. Before inspecting and measuring the crystallizer body, select the crystallizer width adjustment operating system as "local manual" mode, and operate the crystallizer width adjustment operating system to loosen the crystallizer width edge. Then clean the gaps in the crystallizer width adjustment guide groove and the corner of the crystallizer copper plate. After cleaning, operate the crystallizer width adjustment operating system to clamp the crystallizer width edge. S2. Based on the inspection and measurement results of the crystallizer body in step S1, perform online diagnosis of the crystallizer. The diagnostic criteria are as follows: the gap at the corner of the crystallizer copper plate is ≤0.3mm; the absolute value of the difference between the length of one side of the inner and outer arcs of the crystallizer copper plate and the standard length of one side of the inner and outer arcs of the crystallizer copper plate is ≤1mm; the absolute value of the relative thickness difference between the inner and outer arcs and the left and right sides of the crystallizer copper plate is ≤3mm; the wear value of the narrow surface of the crystallizer copper plate is ≤1mm; the flatness of the crystallizer copper plate is ≤0.5mm; within 450mm of the top opening along the length direction of the crystallizer copper plate, each crack or scratch must be ≤3.0mm wide, ≤10mm long, and ≤0.5mm deep, and the number of cracks or scratches must be ≤2; beyond 450mm of the top opening along the length direction of the crystallizer copper plate, each crack or scratch must be ≤3.0mm wide. The length is ≤50mm, the depth is ≤0.5mm, and the number of cracks or scratches is ≤2. The area of ​​the plating crack at the meniscus of the copper plate of the crystallizer is ≤30×30mm. 2 The area of ​​plating peeling off at the meniscus of the copper plate in the crystallizer is 0. If the results of the inspection and measurement of the crystallizer body in step S1 meet the diagnostic criteria, the crystallizer is diagnosed as qualified; if the results of the inspection and measurement of the crystallizer body in step S1 do not meet the diagnostic criteria, the crystallizer is diagnosed as unqualified. S3: Open the nozzles in the water spray system at the crystallizer outlet, and set the nozzle valve opening to 25%. Then, check whether the S2 diagnosis is correct by observing whether the spray water from the nozzles directly sprays onto the roller surface of the foot roller at the crystallizer outlet. If the S2 diagnosis indicates that the crystallizer is qualified, the spray water will not directly spray onto the roller surface of the foot roller at the crystallizer outlet.