A high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets

Abstract

The invention discloses a high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets, which comprises the following steps: electromagnetic stirring of the crystallizer, wherein the magnetic field strength at the center of the electromagnetic stirring coil of the crystallizer is controlled within the range of 0 to 100×10 ‑4 T; solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by implementing wide surface insulation in the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area; secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 ‑4 ~150×10 ‑4 T; Secondary cooling electromagnetic stirring post-processing, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring. Implement electromagnetic stirring at the end of solidification. The electromagnetic stirring control method for continuous casting of large-section rectangular ingots of the present invention can improve the efficiency of electromagnetic stirring, reduce the current intensity of electromagnetic stirring, and reduce the power consumption of stirring. It is a low-energy consumption and environmentally friendly production supporting technology.

Description

Technical Field

[0001] The invention belongs to the field of iron and steel metallurgy, and in particular relates to an electromagnetic stirring control method for continuous casting of large-section rectangular billets. Background Art

[0002] As the most commonly used important material in people's daily production and life, the quality and performance requirements of steel have changed with the continuous development of society. Since the key quality indicators of steel materials such as homogeneity, cleanliness and density have an important impact on the mechanical properties of products, as the performance requirements of steel materials products continue to increase. In order to meet the ever-evolving performance requirements of steel materials and effectively promote the upgrading of steel product production technology, a large number of scientific researchers have begun a large number of technical research to promote the quality improvement of steel products. For example, in terms of the control of non-metallic inclusions, for the natural components that can never be completely removed from steel products, in addition to studying the reduction of inclusion ratings to improve the quality control level, they are gradually developing towards the refinement and utilization of non-metallic inclusions. Small and dispersed non-metallic inclusions can provide important nucleation cores for the refinement of grains, thereby achieving the improvement of product performance; another example is the homogenization control of steel products, which has developed from the previous center segregation (the most serious solute enrichment) control research to the full section homogenization, and from macroscopic homogeneity to semi-macroscopic homogeneity and microscopic homogeneity.

[0003] With the continuous upgrading of continuous casting equipment and process technology, the potential of continuous casting efficiency has been continuously released, and large-section continuous casting production has played an important role in it. For example, rails are important components of railway transportation infrastructure. In order to meet the high-speed railway transportation, the number and density of railway line welding joints have been continuously reduced, and high-speed rails have been continuously developed in length; in order to meet the needs of heavy-load freight, the cross-section of heavy-load line rails has increased. Under the specific equipment process technology environment conditions, it is very important to break through the core technical problems of large-section continuous casting production. This is mainly because after the cross-section of the ingot increases, the difference in local solidification rate of the cross-section increases, and the difficulty of homogeneity control increases, especially the central macro and semi-macro segregation will intensify, which seriously affects the product application performance and organizational regulation. For example, the segregation of carbon and manganese in the center of the high-carbon steel ingot will cause carbide and martensite precipitation; central segregation will cause the rail to have an "S" type fracture, etc. Another example is gears, an important component for power transmission. On the one hand, increasing the cross-section of the gear steel continuous casting billet can increase the rolling compression ratio, promote grain refinement and improve performance. However, increasing the billet cross-section will increase the difficulty of controlling the billet homogeneity, affect the regulation of cross-sectional structure uniformity, and even affect the stability of the heat treatment process.

[0004] Ingot quality control has always been an important research field in iron and steel metallurgy, and the internal quality improvement control of large square billet ingots is an even more important and challenging research issue. The existing technology has not yet found a way to regulate the electromagnetic stirring process to achieve ingot quality control.

[0005] In summary, the field of iron and steel metallurgy urgently needs a supporting control technology method based on efficient electromagnetic stirring to achieve effective control of the quality of the ingot. Summary of the invention

[0006] Based on this, in order to make up for the shortcomings of existing steel continuous casting technology, an electromagnetic stirring control method for continuous casting of large-section rectangular billets is provided. The method is based on the supporting control technology of high-efficiency electromagnetic stirring and is tried for continuous casting production of large-section rectangular billets.

[0007] In order to achieve the above purpose, the following technical solutions are adopted:

[0008] The present invention provides a high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets. The following key processes are regulated during the continuous casting of large-section rectangular billets, namely, electromagnetic stirring of continuous casting, superheat of molten steel in tundish casting, secondary cooling of continuous casting and pressure reduction at the end of solidification. Solidification regulation is implemented before and after electromagnetic stirring of secondary cooling of continuous casting, and the electromagnetic stirring process adopts electromagnetic stirring of continuous casting crystallizer combined with electromagnetic stirring of secondary cooling and electromagnetic stirring at the end of solidification, and the control is carried out by the following steps:

[0009] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0~100×10 -4 T;

[0010] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0011] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 ~150×10 -4 T;

[0012] After the secondary cooling electromagnetic stirring, the ingot is forced to cool down after the secondary cooling electromagnetic stirring is completed. The cooling area ranges from 0 to 2000 mm from the secondary cooling electromagnetic stirring.

[0013] Electromagnetic stirring was performed at the end of solidification.

[0014] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface is provided with cooling water at a flow rate of 25 to 30 L / min for accelerated cooling.

[0015] Furthermore, in the secondary cooling electromagnetic stirring post-treatment, the ingot is forcedly cooled by cooling the wide side with 30-40 L / min of cooling water and cooling the narrow side with 40-50 L / min of cooling water.

[0016] Furthermore, the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 ~150×10 -4 T.

[0017] Furthermore, the control method further comprises:

[0018] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 100×10 -4 T;

[0019] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0020] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 T;

[0021] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0022] Electromagnetic stirring was performed at the end of solidification.

[0023] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 25 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 30L / min of cooling water and the narrow surface is cooled with 40L / min of cooling water.

[0024] Furthermore, the control method further comprises:

[0025] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 50×10 -4 T;

[0026] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0027] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4T;

[0028] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0029] Electromagnetic stirring was performed at the end of solidification.

[0030] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 27 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 35L / min of cooling water and the narrow surface is cooled with 45L / min of cooling water.

[0031] Furthermore, the control method further comprises:

[0032] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0T;

[0033] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0034] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T;

[0035] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0036] Electromagnetic stirring was performed at the end of solidification.

[0037] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 30 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 40L / min of cooling water and the narrow surface is cooled with 50L / min of cooling water.

[0038] Furthermore, the cross-sectional dimensions of the large-section rectangular billet may include cross-sectional dimensions of 280 mm×380 mm, 320 mm×410 mm, and 360 mm×450 mm.

[0039] The present invention has the following beneficial technical effects:

[0040] The electromagnetic stirring control method for continuous casting of large-section rectangular billets of the present invention significantly improves the efficiency of continuous casting electromagnetic stirring by changing the solidification structure of the billet, significantly reduces the power consumption of electromagnetic stirring, reduces the equiaxed crystal area in the center of the billet, but slightly improves the center segregation, and realizes a low-energy-consumption, high-quality, low-cost and green production method for high-quality large-section rectangular billets.

[0041] The electromagnetic stirring control method for continuous casting of large-section rectangular billets of the present invention can improve the electromagnetic stirring efficiency, reduce the electromagnetic stirring current intensity, and reduce the stirring power consumption, and is a low-energy consumption and environment-friendly production supporting technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 It is a schematic diagram of the cross-sectional morphology of the liquid core (molten pool) at the electromagnetic stirring position at the end of solidification of a large-section rectangular billet;

[0044] Figure 2 Schematic diagram of the comparison of the cross-sectional morphology of the liquid core (molten pool) at the electromagnetic stirring position at the end of solidification of a large-section rectangular billet before and after optimization. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0046] The embodiment of the present invention provides an electromagnetic stirring control method for continuous casting of large-section rectangular billets (hereinafter referred to as "cast billets"), which is a supporting control technology method based on efficient electromagnetic stirring. In the actual production of large-section rectangular billets, as solidification proceeds, the cross-sectional morphology of the molten pool 1 gradually tends to be elliptical and the ratio of the major axis to the minor axis gradually increases. The electromagnetic stirring flow conditions are poor, which greatly reduces the actual problem of electromagnetic stirring current efficiency. Specifically, Figure 1 As shown in the figure, in the actual stirring process, the stirring magnetic field strength increases from the center of the billet to the surface of the billet as the position moves away from the center of the billet, and the corresponding stirring torque also increases. Obviously, the billet thickness ( Figure 1 The moment in the vertical direction (indicated by arrow A) is significantly greater than the moment in the width ( Figure 1The moment in the horizontal direction (width shown in the figure) (indicated by arrow B), that is, the moment at point A is greater than that at point B. However, the flow of molten steel generated by the larger moment at point A cannot play a good role in the small radius arc, while point B with better flow conditions is at a small moment position. Under this condition, the stirring intensity is generally increased by increasing the current intensity, which undoubtedly increases the power consumption.

[0047] The control method proposed in the present invention is based on the actual characteristics of the solidification of large-section rectangular billets. It mainly adjusts the cooling and solidification process of the wide and narrow surfaces of the billet, optimizes the cross-sectional morphology of the liquid core molten pool of the billet, strengthens the scientific configuration of electromagnetic stirring parameters, accurately adjusts the timing of steel liquid nucleation in the central area, improves the centrality of the liquid core molten pool on the billet cross section, comprehensively improves the electromagnetic stirring efficiency, realizes low-energy and high-efficiency stirring, and promotes high-quality and low-cost production of billets.

[0048] The embodiment of the present invention provides an efficient electromagnetic stirring control method for continuous casting of large-section rectangular billets. The continuous casting stage of the large-section rectangular billet sequentially performs the following processes: continuous casting electromagnetic stirring, tundish casting molten steel superheat, continuous casting secondary cooling and solidification end pressing. In the continuous casting electromagnetic stirring stage, the continuous casting crystallizer electromagnetic stirring combined with secondary cooling electromagnetic stirring is used, and the control is performed by the following steps:

[0049] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0~100×10 -4 T;

[0050] Solidification control is performed before the implementation of electromagnetic stirring in the secondary cooling process. The wide surface of the 1000-2000mm area before electromagnetic stirring is kept warm, and the narrow surface is accelerated in this area. The narrow surface is cooled with cooling water at a rate of 25-30L / min. The cross section of the molten pool before and after optimization is shown in Figure 1. Figure 2 As shown, the cross section of the molten pool 1 before optimization is as follows Figure 2 The black solid line in the middle shows the optimized cross section of the molten pool 2. Figure 2 Indicated by the black dashed line.

[0051] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 ~150×10 -4 T;

[0052] After the secondary cooling electromagnetic stirring, forced cooling is applied to the ingot after the secondary cooling electromagnetic stirring is completed. The cooling area ranges from 0 to 2000 mm from the secondary cooling electromagnetic stirring. Forced cooling of the ingot is cooling the wide surface with 30 to 40 L / min of cooling water and the narrow surface with 40 to 50 L / min of cooling water.

[0053] Electromagnetic stirring was performed at the end of solidification. The magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 ~150×10 -4 T.

[0054] In a preferred embodiment, the control method further comprises:

[0055] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 100×10 -4 T;

[0056] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0057] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 T;

[0058] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0059] Electromagnetic stirring was performed at the end of solidification.

[0060] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 25 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T. In the secondary cooling electromagnetic stirring post-treatment, the ingot was forcedly cooled by cooling the wide side with 30 L / min of cooling water and the narrow side with 40 L / min of cooling water.

[0061] In a preferred embodiment, the control method further comprises:

[0062] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 50×10 -4 T;

[0063] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0064] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T;

[0065] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0066] Electromagnetic stirring was performed at the end of solidification.

[0067] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 27 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 T. In the secondary cooling electromagnetic stirring post-treatment, the ingot was forced to cool with cooling water at a flow rate of 35 L / min for the wide side and 45 L / min for the narrow side.

[0068] In a preferred embodiment, the control method further comprises:

[0069] Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0T;

[0070] Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time;

[0071] Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T;

[0072] Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring;

[0073] Electromagnetic stirring was performed at the end of solidification.

[0074] Furthermore, during the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at a flow rate of 30 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T. In the secondary cooling electromagnetic stirring post-treatment, the ingot is forcedly cooled by cooling the wide side with 40 L / min of cooling water and the narrow side with 50 L / min of cooling water.

[0075] Preferably, the cross-sectional dimensions of the large-section rectangular billet may include cross-sectional dimensions of 280 mm×380 mm, 320 mm×410 mm, and 360 mm×450 mm.

[0076] The wide side of the ingot is the side in the length direction of the rectangular ingot, and the narrow side of the ingot is the side in the width direction of the rectangular ingot.

[0077] Example 1

[0078] This embodiment is a method for controlling electromagnetic stirring during continuous casting of large square billets of U75V heavy rail steel with a cross section of 280mm×380mm, specifically:

[0079] The solidification control at the end of solidification or before electromagnetic stirring is carried out by keeping the wide surface warm in the 1000-2000mm area before electromagnetic stirring and accelerating the narrow surface cooling in this area. Under this condition, 25L / min of cooling water is supplied to the narrow surface.

[0080] Furthermore, after the secondary cooling electromagnetic stirring is completed, the ingot is forcedly cooled. The cooling area ranges from 0 to 2000 mm from the secondary cooling electromagnetic stirring. The cooling water volume is 30 L / min on the wide side and 40 L / min on the narrow side.

[0081] The continuous casting electromagnetic stirring process parameters are matched, and the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 100×10 - 4 T, magnetic field strength at the center of the secondary cooling electromagnetic stirring coil 100×10 -4 T, magnetic field strength at the center of electromagnetic stirring coil at the end of solidification: 150×10 -4 T.

[0082] The solidification structure of heavy rail steel ingots produced by the technology of the present invention was inspected. The area ratio of equiaxed crystal zone of the ingot was 5.3% lower than that of the conventional high crystallizer electromagnetic stirring intensity production process (for example, reduced from 24% to 18.7%), and the center C segregation degree was controlled at 1.08, slightly better than 1.10 of the conventional production process; the power consumption of electromagnetic stirring in the production process was statistically analyzed, which reduced the production power consumption cost by 3.17 yuan / ton of steel.

[0083] Example 2

[0084] This embodiment is a method for controlling electromagnetic stirring during continuous casting of large square billets of U78CrV heavy rail steel with a cross section of 320mm×410mm, specifically:

[0085] The solidification control at the end of solidification or before electromagnetic stirring is carried out by keeping the wide surface warm in the 1000-2000mm area before electromagnetic stirring and accelerating the narrow surface cooling in this area. Under this condition, 27L / min of cooling water is supplied to the narrow surface.

[0086] Furthermore, after the secondary cooling electromagnetic stirring is completed, the ingot is forcedly cooled. The cooling area ranges from 0 to 2000 mm from the secondary cooling electromagnetic stirring. The cooling water volume is 35 L / min on the wide side and 45 L / min on the narrow side.

[0087] The continuous casting electromagnetic stirring process parameters are matched, and the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 50×10 -4 T, magnetic field strength at the center of the secondary cooling electromagnetic stirring coil 150×10 -4 T, magnetic field strength at the center of electromagnetic stirring coil at the end of solidification 100×10 -4 T.

[0088] The solidification structure of the heavy rail steel ingot produced by the technology of the present invention was inspected. The area ratio of the equiaxed crystal zone of the ingot was 6.4% lower than that of the conventional high crystallizer electromagnetic stirring intensity production process (for example, reduced from 27% to 20.6%), and the center C segregation degree was controlled at 1.09, slightly better than 1.10 of the conventional production process; the power consumption of electromagnetic stirring in the production process was statistically analyzed, which reduced the production power consumption cost by 2.91 yuan / ton of steel.

[0089] Example 3

[0090] This embodiment is a method for controlling electromagnetic stirring during continuous casting of 45M steel blooms with a cross-section of 360mm×450mm, specifically:

[0091] The solidification control at the end of solidification or before electromagnetic stirring is carried out by keeping the wide surface warm in the 1000-2000mm area before electromagnetic stirring and accelerating the narrow surface cooling in this area. Under this condition, 30L / min of cooling water is supplied to the narrow surface.

[0092] Furthermore, after the secondary cooling electromagnetic stirring is completed, the ingot is forcedly cooled. The cooling area ranges from 0 to 2000 mm from the secondary cooling electromagnetic stirring. The cooling water volume is 40 L / min on the wide side and 50 L / min on the narrow side.

[0093] The continuous casting electromagnetic stirring process parameters are matched, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0T, and the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T, magnetic field strength at the center of electromagnetic stirring coil at the end of solidification: 150×10 -4 T.

[0094] The solidification structure of heavy rail steel ingots produced by the technology of the present invention was inspected. The area ratio of the equiaxed crystal zone of the ingot was 6.1% lower than that of the conventional high crystallizer electromagnetic stirring intensity production process (for example, reduced from 26.9% to 20.8%), and the center C segregation degree was controlled at 1.11, which was significantly better than 1.14 of the conventional production process. The power consumption of electromagnetic stirring in the production process was statistically analyzed, which reduced the production power consumption cost by 2.91 yuan / ton of steel.

[0095] The above embodiments illustrate that, by adopting the electromagnetic stirring control method of the present invention, the solidification structure of the ingot is changed, the continuous casting electromagnetic stirring efficiency is significantly improved, the electromagnetic stirring power consumption is significantly reduced, the equiaxed crystal zone in the center of the ingot is reduced, but the center segregation is slightly improved.

[0096] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope of the embodiments disclosed in the claims. Although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0097] Those skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. An efficient electromagnetic stirring control method for continuous casting of large-section rectangular billets, wherein the following processes are regulated during the continuous casting of large-section rectangular billets: continuous casting electromagnetic stirring, tundish casting steel liquid superheat, continuous casting secondary cooling and solidification end pressure reduction, characterized in that: Solidification control is implemented before and after the electromagnetic stirring of the continuous casting secondary cooling, and the electromagnetic stirring process adopts the electromagnetic stirring of the continuous casting crystallizer combined with the electromagnetic stirring of the secondary cooling and the electromagnetic stirring at the end of solidification, including the following steps for control: Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0~100×10 -4 T; Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring. The wide surface of the area 1000-2000mm before the secondary cooling electromagnetic stirring is kept warm, and the narrow surface is accelerated cooled in this area. The narrow surface is accelerated cooled with cooling water at a flow rate of 25-30L / min. Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 ~150×10 -4 T; Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring; wherein, the forced cooling of the ingot is cooling the wide surface with 30 to 40L / min of cooling water, and cooling the narrow surface with 40 to 50L / min of cooling water; Electromagnetic stirring was performed at the end of solidification; wherein the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 ~150×10 -4 T; Among them, the cross-sectional dimensions of the large-section rectangular billet include 280mm×380mm, 320mm×410mm, and 360mm×450mm.

2. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 1, characterized in that: The control method further comprises: Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 100×10 -4 T; Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time; Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 100×10 -4 T; Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring; Electromagnetic stirring was performed at the end of solidification.

3. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 2, characterized in that: During the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at 25 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 30L / min of cooling water and the narrow surface is cooled with 40L / min of cooling water.

4. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 1, characterized in that: The control method further comprises: Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 50×10 -4 T; Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time; Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T; Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring; Electromagnetic stirring was performed at the end of solidification.

5. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 4, characterized in that: During the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at 27 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 100×10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 35L / min of cooling water and the narrow surface is cooled with 45L / min of cooling water.

6. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 1, characterized in that: The control method further comprises: Crystallizer electromagnetic stirring, the magnetic field strength at the center of the crystallizer electromagnetic stirring coil is controlled at 0T; Solidification control is performed before the implementation of the secondary cooling electromagnetic stirring, by performing wide surface insulation on the 1000-2000mm area before the secondary cooling electromagnetic stirring, and performing narrow surface accelerated cooling in this area at the same time; Secondary cooling electromagnetic stirring, the magnetic field strength at the center of the secondary cooling electromagnetic stirring coil is 150×10 -4 T; Secondary cooling electromagnetic stirring post-treatment, after the secondary cooling electromagnetic stirring is completed, the ingot is forced to cool, and the cooling area range is 0 to 2000mm from the secondary cooling electromagnetic stirring; Electromagnetic stirring was performed at the end of solidification.

7. The high-efficiency electromagnetic stirring control method for continuous casting of large-section rectangular billets according to claim 6, characterized in that: During the solidification control before the implementation of the secondary cooling electromagnetic stirring, the narrow surface was cooled with cooling water at 30 L / min for accelerated cooling; the magnetic field strength at the center of the electromagnetic stirring coil at the end of solidification was 150 × 10 -4 T; in the secondary cooling electromagnetic stirring post-treatment, the ingot is subjected to forced cooling, that is, the wide surface is cooled with 40L / min of cooling water and the narrow surface is cooled with 50L / min of cooling water.

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