Matching method for round billet continuous casting machine and multi-stage multi-mode electromagnetic stirring device

Abstract

The invention provides a round billet continuous casting machine and multi-stage multi-mode electromagnetic stirring device matching method, and belongs to the technical field of metallurgy continuous casting, and the method comprises the steps that an electromagnetic stirrer in a crystallizer area applies a rotating magnetic field in the initial solidification stage, and the forming quality of an initial solidification shell is optimized; an electromagnetic stirrer in the secondary cooling area utilizes a traveling wave magnetic field to continuously regulate and control the solidification process of the core part of the casting blank; the feeding effect of a final solidification section is remarkably improved through the action of a high-intensity magnetic field by an electromagnetic stirrer in a solidification tail end area, and multiple matching modes are produced to be matched with existing continuous casting processes of different steel grades according to the characteristics of the steel grades, the throwing direction of each area and the type of the electromagnetic stirrer. And then through linkage of the multi-stage multi-mode electromagnetic stirring device and cooperative control over continuous casting process parameters, the equiaxed crystal area of the casting blank is enlarged, segregation is reduced, the internal quality of the casting blank is improved, and the density, uniformity and mechanical performance of the casting blank are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgical continuous casting, and particularly relates to a matching method of a round billet continuous casting machine and a multi-stage multi-mode electromagnetic stirring device. BACKGROUND

[0002] As a key basic material of modern industry, continuous casting round billets play an irreplaceable role in important fields of national economy such as mechanical equipment, energy engineering and transportation. However, the round billets produced by using conventional continuous casting technology often have several internal quality problems, mainly manifested in three typical defects: first, center porosity formed due to insufficient volume shrinkage compensation in the final solidification stage; second, macrosegregation caused by the continuous enrichment of solute elements at the front of the solid-liquid interface; and third, the decrease of center purity caused by the forced migration and aggregation of non-metallic inclusions at the solidification end.

[0003] In-depth research shows that the formation mechanism of these defects is closely related to the multi-physical field coupling in the solidification process of the molten steel, which involves three aspects: first, the heat transfer process driven by the temperature gradient, second, the mass transfer phenomenon caused by the solute concentration gradient, and third, the significant influence of molten steel flow on the solidification structure. The complex multi-field interaction ultimately determines the internal quality characteristics of the round billet. Electromagnetic stirring technology, as a revolutionary innovation in modern continuous casting process, provides a precise control means for the solidification process of molten steel through non-contact electromagnetic force. This technology uses electromagnetic induction principle to apply a specific form of electromagnetic field during continuous casting, inducing controllable forced convection of molten steel, thereby achieving active intervention in the solidification structure. Its core mechanism mainly reflects three aspects: first, the melt flow driven by electromagnetic force can effectively break the primary dendrite arms, significantly refining the equiaxed crystal zone; second, the enhanced melt convection promotes the uniform distribution of solute elements, effectively inhibiting the formation of macrosegregation; third, the centrifugal effect generated by electromagnetic stirring can promote the migration of non-metallic inclusions to the periphery, significantly improving the purity of the center region of the billet. Although traditional process optimization such as improvement of the water gap structure and adjustment of the secondary cooling intensity has certain improvement effect on the quality of the billet, it is still necessary to match the traditional process parameters with the multi-stage electromagnetic stirring and systematically study the collaborative control therebetween to optimize the product quality. SUMMARY

[0004] The present application aims to at least solve one of the problems in the prior art or related art.

[0005] Therefore, according to the embodiments of the present application, a matching method of a round billet continuous casting machine and a multi-stage multi-mode electromagnetic stirring device is provided, which comprises:

[0006] According to the state of the molten steel in the upstream and downstream regions of the continuous casting machine, the characteristics of the steel grade and the amount of cooling water, the crystallizer region, the secondary cooling region and the solidification end region are divided on the continuous casting machine.

[0007] Respective electromagnetic stirrers are configured for the crystallizer region, the secondary cooling region and the solidification end region;

[0008] Based on the steel type characteristics, the casting direction of each region and the electromagnetic stirrer type, the electromagnetic stirring parameters are adjusted to generate multiple matching modes.

[0009] In a feasible implementation, the crystallizer region is configured with a rotating electromagnetic stirrer, the secondary cooling region is configured with a traveling wave electromagnetic stirrer, and the solidification end region is configured with a traveling wave electromagnetic stirrer.

[0010] In a feasible implementation, the rotating electromagnetic stirrer has a current intensity of 100A-400A and an oscillation frequency of 1.0Hz-5.0Hz.

[0011] The traveling wave electromagnetic stirrer has a current intensity of 200A-900A and an oscillation frequency of 1.0Hz-5.0Hz.

[0012] In a feasible implementation, the matching modes include four modes, the first matching mode is used for low-carbon steel continuous casting process, the second matching mode is used for medium-carbon steel continuous casting process, the third matching mode is used for high-alloy steel continuous casting process, and the fourth matching mode is used for high-carbon steel continuous casting process.

[0013] In a feasible implementation, the first matching mode includes:

[0014] The rotating electromagnetic stirrer of the crystallizer region is controlled to stir the molten steel in the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz-5.0Hz and a current intensity of 100A-400A within a range of 0.5m-0.7m from the meniscus;

[0015] The traveling wave electromagnetic stirrer of the secondary cooling region is controlled to stir the molten steel in the casting direction of the secondary cooling region at an oscillation frequency of 1.0Hz-5.0Hz and a current intensity of 200A-600A within a range of 9.5m-11.5m from the meniscus;

[0016] The traveling wave electromagnetic stirrer of the solidification end region is controlled to stir the molten steel in the casting direction of the solidification end region at an oscillation frequency of 1.0Hz-5.0Hz and a current intensity of 200A-900A within a range of 14.5m-17.5m from the meniscus.

[0017] In a feasible implementation, the second matching mode includes:

[0018] A rotary electromagnetic stirrer controlling the crystallizer region stirs molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus.

[0019] The traveling wave electromagnetic stirrer in the secondary cooling zone is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the secondary cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus.

[0020] The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the billet pulling direction in the range of 14.5m to 17.5m from the meniscus with an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A.

[0021] In one feasible implementation, the third matching pattern includes:

[0022] A rotary electromagnetic stirrer controlling the crystallizer region stirs molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus.

[0023] The traveling wave electromagnetic stirrer in the secondary cooling zone is controlled to stir the molten steel in the billet pulling direction of the secondary cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus.

[0024] The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the range of 14.5m to 17.5m from the meniscus with an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A.

[0025] In one feasible implementation, the fourth matching pattern includes:

[0026] A rotary electromagnetic stirrer controlling the crystallizer region stirs molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus.

[0027] The traveling wave electromagnetic stirrer in the secondary cooling zone is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the secondary cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus.

[0028] The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the range of 14.5m to 17.5m from the meniscus with an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A.

[0029] In one feasible implementation, under the first matching mode, the second matching mode, the third matching mode, and the fourth matching mode, the cooling water volume in the secondary cooling zone is 0.1L / kg to 0.25L / kg.

[0030] In one feasible implementation, a corresponding matching mode is activated based on the detected equiaxed crystal ratio of the billet to expand the equiaxed crystal region of the billet.

[0031] The matching method of a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device proposed in this application has the following advantages compared with the prior art:

[0032] The method for matching a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device provided in this application divides the continuous casting machine into three regions: the crystallizer, the secondary cooling zone, and the solidification end, and independently configures electromagnetic stirrers for each region. This precisely matches the solidification characteristics of the molten steel in each region of the continuous casting machine. The electromagnetic stirrer in the crystallizer region applies a rotating magnetic field during the initial solidification stage to optimize the formation quality of the initial solidified shell. The electromagnetic stirrer in the secondary cooling zone region uses a traveling wave magnetic field to continuously regulate the solidification process of the billet core. The electromagnetic stirrer in the solidification end region significantly improves the feeding effect of the final solidification section through the action of a strong magnetic field. Based on the characteristics of the steel grade, the billet pulling direction of each region, and the type of electromagnetic stirrer, multiple matching modes are produced to match the existing continuous casting processes for different steel grades. Furthermore, through the linkage of the multi-stage, multi-mode electromagnetic stirring device and the coordinated control of the continuous casting process parameters, the equiaxed crystal zone of the billet is expanded, segregation is reduced, the internal quality of the billet is improved, and the density, uniformity, and mechanical properties of the billet are enhanced, further improving the yield of the continuously cast billet. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 A schematic flowchart illustrating the steps of a matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device, provided in this application.

[0035] Figure 2 A schematic structural diagram illustrating the matching of a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device according to an embodiment of this application;

[0036] Figure 3 A streamline diagram of molten steel when a rotary electromagnetic stirrer is applied in the crystallizer region;

[0037] Figure 4 The streamline diagram of molten steel when a traveling wave linear electromagnetic stirrer is applied in the secondary cooling zone;

[0038] Figure 5 The streamline diagram of molten steel when a traveling wave linear electromagnetic stirrer is applied in the solidification end region;

[0039] Figure 6 To calculate the solute distribution diagrams with and without a multi-stage, multi-mode electromagnetic stirring device using numerical simulation;

[0040] in, Figure 2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0041] 1. Multi-mode electromagnetic device; 2. Continuous casting machine; 3. Steel ladle;

[0042] 11. Rotary electromagnetic stirrer; 12. Traveling wave electromagnetic stirrer in the secondary cooling zone; 13. Traveling wave electromagnetic stirrer at the end of solidification. Detailed Implementation

[0043] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0045] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0047] like Figure 1 As shown, according to an embodiment of this application, a matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device is proposed, including:

[0048] Step 100: Based on the state of the molten steel, the characteristics of the steel grade, and the amount of cooling water in the upstream and downstream areas of the continuous casting machine, divide the continuous casting machine into the crystallizer area, the secondary cooling zone area, and the solidification end area.

[0049] Step 200: Configure independent electromagnetic stirrers for the crystallizer area, the secondary cooling zone area, and the solidification end area respectively;

[0050] Step 300: Based on the characteristics of the steel grade, the billet pulling direction of each region, and the type of electromagnetic stirrer, adjust the electromagnetic stirring parameters to generate multiple matching modes.

[0051] The method for matching a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device provided in this application involves molten steel entering the continuous casting machine 2 from the ladle 3. The continuous casting machine 2 is divided into three regions: a crystallizer, a secondary cooling zone, and a solidification end zone, each independently equipped with an electromagnetic stirrer. This precisely matches the solidification characteristics of the molten steel in each region of the continuous casting machine 2. The electromagnetic stirrer in the crystallizer region applies a rotating magnetic field during the initial solidification stage to optimize the formation quality of the initial solidified shell. The electromagnetic stirrer in the secondary cooling zone continuously regulates the solidification process of the billet core using a traveling wave magnetic field. The electromagnetic stirrer in the solidification end zone significantly improves the feeding effect of the final solidification section through a strong magnetic field. Based on the characteristics of the steel grade, the casting direction of each region, and the type of electromagnetic stirrer, multiple matching modes are produced to match existing continuous casting processes for different steel grades. Furthermore, through the linkage of the multi-stage, multi-mode electromagnetic stirring device and the coordinated control of continuous casting process parameters, the equiaxed crystal zone of the billet is expanded, segregation is reduced, the internal quality of the billet is improved, and the density, uniformity, and mechanical properties of the billet are enhanced, further increasing the yield of the continuously cast billet.

[0052] The inventors discovered that the difficulty in improving the quality of continuously cast billets in existing technologies lies in clarifying the process matching optimization under multi-field coupling conditions and the quantitative relationship between electromagnetic parameters and metallurgical effects. Although some existing technologies have used rotary electromagnetic stirrers in conjunction with the continuous casting machine 2 to stir the molten steel, they have not formed a collaborative working mode between the three regions of the crystallizer, secondary cooling zone, and solidification end and the stirring device, as is the case in traditional processes, resulting in limited homogenization of the cast billets. In the embodiments of this application, independent electromagnetic stirring devices are set up in the three regions to form a multi-level, multi-mode electromagnetic stirring device. Through the collaborative control of the multi-level, multi-mode electromagnetic stirring device and traditional process parameters, targeted matching control optimization is performed on the matching production scheme between the continuous casting process and the electromagnetic stirrers installed in the crystallizer region, secondary cooling zone region, and solidification end region, respectively, to achieve homogenized production of continuously cast round billets.

[0053] In one feasible implementation, a rotary electromagnetic stirrer 11 is configured in the crystallizer region, a traveling wave electromagnetic stirrer is configured in the secondary cooling zone region, and a traveling wave electromagnetic stirrer is configured in the solidification end region.

[0054] In this technical solution, the rotary electromagnetic stirrer 11 generates a tangential magnetic field to drive the molten steel to rotate and flow circumferentially. In the crystallizer region, it promotes the floating of inclusions in the molten steel and refines equiaxed crystals, thus optimizing the formation quality of the initial solidified shell of the billet. The traveling wave electromagnetic stirrer generates a longitudinal electromagnetic force to drive the axial flow of molten steel in the secondary cooling zone and the solidification end zone, enhancing the uniformity of the solute, transporting high-temperature molten steel over long distances, avoiding the attenuation of the flow field caused by rotary stirring, continuously controlling the solidification process of the billet core in the secondary cooling zone, and improving the feeding effect of the final solidification section of the billet in the solidification end zone. Through the multi-stage linkage and synergy of different electromagnetic stirrers, the density, uniformity, and mechanical properties of the billet are improved.

[0055] In one feasible implementation, the current intensity of the rotary electromagnetic stirrer 11 is 100A to 400A and the oscillation frequency is 1.0Hz to 5.0Hz; the current intensity of the traveling wave electromagnetic stirrer is 200A to 900A and the oscillation frequency is 1.0Hz to 5.0Hz.

[0056] In this technical solution, the magnetic fields of the rotary electromagnetic stirrer 11 and the traveling wave electromagnetic stirrer maintain low-frequency oscillation to avoid the skin effect caused by high-frequency magnetic fields, prevent the magnetic field from being shielded by the copper wall, and ensure that the magnetic field penetrates the solidified shell of the billet; the crystallizer area uses low current intensity to avoid meniscus fluctuation and slag entrapment; the current intensity is increased in the secondary cooling zone and the solidification end zone to ensure that the magnetic field penetrates the high-viscosity paste-like zone of the billet.

[0057] It is understood that the structure and working principle of both the rotary electromagnetic stirrer 11 and the traveling wave electromagnetic stirrer are existing technologies. Specifically, the traveling wave electromagnetic stirrer used in this application embodiment adopts a heterogeneous iron core type high-energy continuous casting traveling wave linear electromagnetic stirrer disclosed in patent CN118122972B.

[0058] In one feasible implementation, there are four matching modes: the first matching mode is used for low carbon steel continuous casting process, the second matching mode is used for medium carbon steel continuous casting process, the third matching mode is used for high alloy steel continuous casting process, and the fourth matching mode is used for high carbon steel continuous casting process.

[0059] In this technical solution, different stirring modes are customized to match the segregation characteristics of different steel grades with the continuous casting production process. Under multi-field coupling conditions, electromagnetic parameters are matched with metallurgical effects to optimize the process. When the steel grade changes, the corresponding matching mode can be selected directly without repeatedly adjusting the process parameters. Through process matching, production can be quickly switched and put into operation, improving the convenience and continuity of production.

[0060] In one feasible implementation, the first matching mode includes: controlling a rotary electromagnetic stirrer 11 in the crystallizer region to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus; controlling a traveling wave electromagnetic stirrer in the secondary cooling zone region to stir molten steel along the billet-drawing direction of the secondary cooling zone region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus; and controlling a traveling wave electromagnetic stirrer in the solidification end region to stir molten steel along the billet-drawing direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

[0061] In this technical solution, the first matching mode is suitable for producing low-carbon steel billets. Low-carbon steel has low solidification shrinkage, stable unidirectional flow field, avoids slag entrapment, and has weak solute segregation, eliminating the need for reverse stirring to disrupt the channels. A rotary electromagnetic stirrer 11 is configured in the crystallizer area to control the horizontal rotation of the molten steel in the crystallizer area and control the current to eliminate superheat gradient, reduce subcutaneous porosity, control the uniformity of the initial solidification shell, and improve the surface cleanliness of the billet. In the secondary cooling zone, axial stirring with a unidirectional traveling wave magnetic field breaks the columnar crystal bridging. In the solidification end zone, axial stirring with a unidirectional traveling wave magnetic field disturbs the mushy zone, promotes feeding in the mushy zone, disperses solute enrichment, reduces the risk of central porosity, and increases the equiaxed crystal ratio of low-carbon steel.

[0062] In one feasible implementation, the second matching mode includes: controlling a rotary electromagnetic stirrer 11 in the crystallizer region to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus; controlling a traveling wave electromagnetic stirrer in the secondary cooling zone region to stir molten steel in the opposite direction of the billet pulling direction of the secondary cooling zone region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus; and controlling a traveling wave electromagnetic stirrer in the solidification end region to stir molten steel along the billet pulling direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

[0063] In this technical solution, the second matching mode is suitable for producing medium carbon steel billets. Medium carbon steel exhibits intense three-crystallization reactions and well-developed columnar crystals. Reverse stirring in the secondary cooling zone disrupts the directional growth of dendrites, while unidirectional feeding at the solidification end alleviates V-shaped segregation. A rotary electromagnetic stirrer 11 is configured in the crystallizer area to control the horizontal rotation of the molten steel within the crystallizer area, and to control the current to eliminate superheat gradients, reduce subcutaneous porosity, control the uniformity of the initial solidified shell, and improve the surface cleanliness of the billet. Axial stirring using a reverse traveling wave magnetic field in the secondary cooling zone counteracts the inertia of columnar crystal growth, inhibits dendrite bridging, and eliminates negative segregation bands. Axial stirring using a unidirectional traveling wave magnetic field at the solidification end disturbs the mushy region, maintains axial solute diffusion, avoids central shrinkage cavities, and increases the equiaxed crystal ratio of the medium carbon steel.

[0064] In one feasible implementation, the third matching mode includes: controlling a rotary electromagnetic stirrer 11 in the crystallizer region to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus; controlling a traveling wave electromagnetic stirrer in the secondary cooling zone region to stir molten steel along the billet-drawing direction of the secondary cooling zone region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus; and controlling a traveling wave electromagnetic stirrer in the solidification end region to stir molten steel in the opposite direction along the billet-drawing direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

[0065] In this technical solution, the third matching mode is suitable for producing high-alloy steel billets. High-alloy elements tend to accumulate in the solidification end region, forming segregation channels. In the secondary cooling zone, axial stirring with a co-directional traveling wave magnetic field prevents the thickening of the viscous layer. In the solidification end region, axial stirring with a reverse traveling wave magnetic field forces solute redistribution. A rotary electromagnetic stirrer 11 is configured in the crystallizer region to control the horizontal rotation of the molten steel in the crystallizer region and control the current to eliminate superheat gradients, reduce subcutaneous porosity, control the uniformity of the initial solidification shell, and improve the surface cleanliness of the billet. In the secondary cooling zone, axial stirring with a co-directional traveling wave magnetic field maintains moderate flow intensity of the molten steel, preventing excessive viscosity of the high-alloy steel from causing flow field failure. In the solidification end region, axial stirring with a unidirectional traveling wave magnetic field forces turbulence in the mushy region, breaks up segregation channels, and increases the equiaxed crystal ratio of the high-alloy steel.

[0066] In one feasible implementation, the fourth matching mode includes: controlling a rotary electromagnetic stirrer 11 in the crystallizer region to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus; controlling a traveling wave electromagnetic stirrer in the secondary cooling zone region to stir molten steel in the opposite direction of the secondary cooling zone region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus; and controlling a traveling wave electromagnetic stirrer in the solidification end region to stir molten steel in the opposite direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

[0067] In this technical solution, the fourth matching mode is suitable for producing high-carbon steel. High-carbon steel has high viscosity in its paste-like region. In the secondary cooling zone, a reverse traveling wave magnetic field is used for stirring to enhance shear force. At the end of solidification, another reverse traveling wave magnetic field is used to disrupt segregation channels and prevent severe solute enrichment. A rotary electromagnetic stirrer 11 is configured in the crystallizer region to control the horizontal rotation of the molten steel within the crystallizer region. The current is controlled to eliminate superheat gradients, reduce subcutaneous porosity, control the uniformity of the initial solidified shell, improve the surface cleanliness of the billet, and simultaneously protect the stability of the meniscus to prevent slag entrapment in high-carbon steel. Axial stirring with a co-directional traveling wave magnetic field is used in both the secondary cooling zone and the end of solidification region, doubly disrupting carbon enrichment paths and increasing the equiaxed crystal ratio of high-carbon steel.

[0068] In one feasible implementation, under the first matching mode, the second matching mode, the third matching mode, and the fourth matching mode, the cooling water volume in the secondary cooling zone is 0.1L / kg to 0.25L / kg.

[0069] In this technical solution, the cooling water volume in the secondary cooling zone is within the range of 0.1L / kg to 0.25L / kg under all four modes. The cooling water volume in the secondary cooling zone does not need to be significantly adjusted under the four modes, so that both the solidification rate and the stirring effect can be taken into account.

[0070] In this technical solution, the minimum cooling water volume is 0.1L / kg to delay the solidification of the billet and extend the effective stirring time; the maximum cooling water volume is 0.25L / kg to accelerate the growth of the solidified shell and match the high billet pulling speed.

[0071] In one feasible implementation, a corresponding matching mode is activated based on the detected equiaxed crystal ratio of the billet to expand the equiaxed crystal region of the billet.

[0072] In this technical solution, a suitable matching mode is activated based on the real-time equiaxed crystal ratio, the process is dynamically optimized, and timely adjustments are made. This is beneficial for rapidly expanding the equiaxed crystal zone of the billet, reducing segregation, improving the internal quality of the billet, and increasing the pass rate of flaw detection for continuously cast billets and rolled products.

[0073] In some examples, when the equiaxed crystal ratio is <20%, the process switches to a high-current mode or a reverse stirring mode to expand the equiaxed crystal region of the billet in a timely manner; when the equiaxed crystal ratio is >30%, the process switches to a low-current mode to reduce the current in order to avoid negative segregation caused by excessive stirring, thereby dynamically optimizing the billet quality.

[0074] Example:

[0075] The high-alloy steel billet is produced using the first matching mode. A rotary electromagnetic stirrer 11 in the crystallizer region is controlled to stir the molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0 Hz and a current intensity of 100 A within a range of 0.5 m from the meniscus. A traveling wave electromagnetic stirrer 12 in the secondary cooling zone region is controlled to stir the molten steel along the billet-drawing direction of the secondary cooling zone region at an oscillation frequency of 1.0 Hz and a current intensity of 200 A within a range of 9.5 m from the meniscus. A traveling wave electromagnetic stirrer 13 in the solidification end region region is controlled to stir the molten steel along the billet-drawing direction of the solidification end region at an oscillation frequency of 1.0 Hz and a current intensity of 200 A within a range of 14.5 m from the meniscus.

[0076] Figure 2 A schematic diagram of a multi-stage, multi-mode electromagnetic stirring device installed on continuous casting machine 2 is shown. Electromagnetic stirrers are installed at different locations on continuous casting machine 2. Since each electromagnetic stirrer affects the flow temperature and other factors of the molten steel during solidification, it inevitably affects the quality of the final continuously cast billet product. Therefore, the matching method for the multi-stage, multi-mode electromagnetic stirring device is not to blindly stack electromagnetic stirrer equipment on continuous casting machine 2, but rather to change the stirring mode and electromagnetic parameters of the stirrer according to the state of the molten steel in the upstream and downstream areas of continuous casting machine 2, as well as the steel grade and cooling water volume.

[0077] Figure 3 The streamline diagram of molten steel when a rotary electromagnetic stirrer 11 is applied in the crystallizer region is shown. It can be seen that the molten steel exhibits horizontal rotating circular motion in the crystallizer region. Figure 4 The streamline diagram of molten steel when a traveling wave linear electromagnetic stirrer is applied in the secondary cooling zone is shown. It can be seen that the molten steel exhibits a longitudinal swirling flow pattern in the secondary cooling zone and there are two longitudinal stirring zones. At this time, the direction of the traveling wave electromagnetic force is the same as the direction of billet pulling. Figure 5 The streamline diagram of molten steel when a traveling wave linear electromagnetic stirrer is applied in the solidification end region is shown. It can be seen that in the solidification end region, the molten steel exhibits a longitudinal swirling flow mode and there are two longitudinal stirring zones. At this time, the direction of the traveling wave electromagnetic force is opposite to the direction of billet pulling.

[0078] Figure 6 Numerical simulations were used to calculate the solute distribution under a multi-stage, multi-mode electromagnetic stirring device and the solute distribution without a multi-stage, multi-mode electromagnetic stirring device. It can be seen that after matching the multi-stage, multi-mode electromagnetic stirring device technology with the production process parameters of the traditional continuous casting machine 2, the solute is uniformly distributed, the peak carbon segregation rate is significantly reduced, and the carbon range is reduced from 0.21% to 0.07%.

[0079] It will be readily understood by those skilled in the art that the above embodiments can be freely combined and superimposed without conflict.

[0080] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A method for matching a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device, characterized in that, The matching method between the round billet continuous casting machine and the multi-stage, multi-mode electromagnetic stirring device includes: Based on the state of molten steel, steel characteristics, and cooling water volume in the upstream and downstream areas of the continuous casting machine, the continuous casting machine is divided into a crystallizer area, a secondary cooling zone area, and a solidification end area. Independent electromagnetic stirrers are respectively configured for the crystallizer region, the secondary cooling zone region, and the solidification end region; Based on the characteristics of the steel grade, the billet pulling direction of each region, and the type of electromagnetic stirrer, the electromagnetic stirring parameters are adjusted to generate multiple matching modes.

2. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 1, characterized in that, A rotary electromagnetic stirrer is configured in the crystallizer area, a traveling wave electromagnetic stirrer is configured in the secondary cooling zone area, and a traveling wave electromagnetic stirrer is configured in the solidification end area.

3. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 2, characterized in that, The rotary electromagnetic stirrer has a current intensity of 100A to 400A and an oscillation frequency of 1.0Hz to 5.0Hz. The traveling wave electromagnetic stirrer has a current intensity of 200A to 900A and an oscillation frequency of 1.0Hz to 5.0Hz.

4. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 1, characterized in that, There are four matching modes: the first matching mode is used for low carbon steel continuous casting process, the second matching mode is used for medium carbon steel continuous casting process, the third matching mode is used for high alloy steel continuous casting process, and the fourth matching mode is used for high carbon steel continuous casting process.

5. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 4, characterized in that, The first matching pattern includes: A rotary electromagnetic stirrer in the crystallizer region is controlled to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus. The traveling wave electromagnetic stirrer in the second cooling zone is controlled to stir the molten steel in the billet pulling direction of the second cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus. The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the billet pulling direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

6. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 4, characterized in that, The second matching pattern includes: A rotary electromagnetic stirrer in the crystallizer region is controlled to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus. The traveling wave electromagnetic stirrer in the second cooling zone is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the second cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus. The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the billet pulling direction of the solidification end region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A within a range of 14.5m to 17.5m from the meniscus.

7. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 4, characterized in that, The third matching mode includes: A rotary electromagnetic stirrer in the crystallizer region is controlled to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus. The traveling wave electromagnetic stirrer in the second cooling zone is controlled to stir the molten steel in the billet pulling direction of the second cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus. The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the range of 14.5m to 17.5m from the meniscus with an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A.

8. The matching method between a round billet continuous casting machine and a multi-stage, multi-mode electromagnetic stirring device according to claim 4, characterized in that, The fourth matching mode includes: A rotary electromagnetic stirrer in the crystallizer region is controlled to stir molten steel along the tangential direction of the crystallizer region at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 100A to 400A within a range of 0.5m to 0.7m from the meniscus. The traveling wave electromagnetic stirrer in the second cooling zone is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the second cooling zone at an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 600A within a range of 9.5m to 11.5m from the meniscus. The traveling wave electromagnetic stirrer in the solidification end region is controlled to stir the molten steel in the opposite direction of the billet pulling direction in the range of 14.5m to 17.5m from the meniscus with an oscillation frequency of 1.0Hz to 5.0Hz and a current intensity of 200A to 900A.

9. A method for matching a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device according to any one of claims 5 to 8, characterized in that, In the first matching mode, the second matching mode, the third matching mode, and the fourth matching mode, the cooling water volume in the second cooling zone is 0.1L / kg to 0.25L / kg.

10. A method for matching a round billet continuous casting machine with a multi-stage, multi-mode electromagnetic stirring device according to any one of claims 5 to 8, characterized in that, Based on the detected equiaxed crystal ratio of the billet, the corresponding matching mode is activated to expand the equiaxed crystal region of the billet.

Images