A flow control method for roller type electromagnetic stirring device

Abstract

The present invention relates to the technical field of electromagnetic stirring, and in particular to a flow control method for a roller-type electromagnetic stirring device, comprising symmetrically arranging a plurality of flow control rollers on two wide surfaces of a billet, determining the working modes of a first flow control roller and a third flow control roller, and when molten steel is introduced into the billet at a water inlet, detecting the temperature and the height of the molten steel liquid level at a plurality of detection points arranged in an array on the two wide surfaces of the billet between the first flow control roller and the third flow control roller, further judging whether it is necessary to adjust the flow state of the molten steel, and determining the adjustment method of the flow state of the molten steel and the adjustment parameters of the flow control rollers, judging whether the adjustment of the flow state of the molten steel is qualified based on the change of the height of the molten steel liquid level before and after the adjustment, and continuously monitoring the flow state of the molten steel of the casting. The present invention realizes the control of the flow state of the molten steel during electromagnetic stirring by determining the adjustment object, adjustment timing and adjustment means.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic stirring, and in particular to a flow control method for a roller type electromagnetic stirring device. Background Art

[0002] As an important means to control the solidification structure of the ingot and improve the cleanliness and quality of the ingot, electromagnetic stirring has been widely used in the continuous casting process of steel. According to the different installation positions, it can be divided into electromagnetic stirring of the crystallizer, electromagnetic stirring of the secondary cooling zone and electromagnetic stirring of the solidification end. Among them, electromagnetic stirring of the crystallizer is mainly used to improve the flow field in the crystallizer, eliminate the superheat of the molten steel and remove inclusions. Therefore, it is necessary to control the flow state of the molten steel during the electromagnetic stirring process of the crystallizer to improve the quality of the casting after casting.

[0003] Chinese patent publication number: CN114309509B discloses a vertical continuous casting time-space electromagnetic stirring mode control method and device thereof, which can realize long-range cross-region and short-range spiral electromagnetic stirring by adjusting the movement speed and lifting height of the piston rod. The device includes a casting, a crystallizer, a secondary cooling zone, a solidification end, a foot roller, an electromagnetic stirrer, an upper base, a piston rod, a lifting device, a displacement sensor, a lower base, a computer, a yoke and a coil. The height of the electromagnetic stirrer is dynamically adjusted by a plurality of lifting devices installed at its lower part and assisted by a computer. By applying an alternating current in the coil, an alternating magnetic field is generated in the casting, and an induced current is generated in the molten steel at the same time. The alternating magnetic field interacts with the induced current to generate an electromagnetic force, thereby driving the molten steel to move. Only one set of electromagnetic stirring device is required, which can effectively replace the original combined electromagnetic stirring, and better solves the problem that the electromagnetic stirring device cannot be adjusted in real time; it can be seen that the vertical continuous casting time-space electromagnetic stirring mode control method and device thereof have the following problems: this invention cannot realize the control of the flow state of the molten steel according to the temperature distribution of the molten steel during electromagnetic stirring. Summary of the invention

[0004] To this end, the present invention provides a flow control method for a roller type electromagnetic stirring device, so as to overcome the problem in the prior art that the flow state of molten steel cannot be controlled according to the temperature distribution of the molten steel during electromagnetic stirring.

[0005] To achieve the above object, the present invention provides a flow control method for a roller type electromagnetic stirring device, comprising:

[0006] Step S1, symmetrically arranging a plurality of flow control rollers on two wide surfaces of the casting billet, including a first flow control roller and a third flow control roller, and setting the length of the first flow control roller from the edge of the casting billet close to the water inlet to a first preset length, and setting the length of a single wavy roller in the flow control rollers to a second preset length; wherein the single flow control roller comprises a brake roller arranged in the middle section of the roller body and two wavy rollers respectively arranged at both ends of the roller body;

[0007] Step S2, determining the working modes of the first flow control roller and the third flow control roller according to the first preset length, the second preset length and the preset coefficient; wherein the working modes include an internal push mode and an external push mode;

[0008] Step S3, when the molten steel is introduced into the ingot through the water inlet, the temperature and the height of the molten steel level at a plurality of detection points between the first flow control roller and the third flow control roller are detected, wherein the plurality of detection points are arranged in an array on two wide surfaces of the ingot;

[0009] Step S4, judging whether the flow state of the molten steel needs to be adjusted according to the characteristics of the surface temperature curve of the ingot;

[0010] Step S5, based on the judgment result, determining the adjustment method of the flow state of the molten steel, and determining the adjustment parameters of the flow control roller, the adjustment method of the flow state of the molten steel includes adjusting the central flow velocity of the molten steel, adjusting the molten steel winding length, adjusting the molten steel winding strength and adjusting the molten steel winding direction, wherein the central flow velocity is determined by the magnetic field strength generated by the brake roller, the molten steel winding length is determined by the spacing between the first flow control roller and the third flow control roller, the molten steel winding strength is determined by the magnetic field strength generated by the traveling wave roller, and the molten steel winding direction is determined by the working mode of the first flow control roller and the third flow control roller;

[0011] Step S6, judging whether the adjustment of the flow state of the molten steel is qualified based on the change of the liquid level of the molten steel before and after the adjustment;

[0012] Step S7, repeating steps S3-S6 to continuously monitor the flow state of molten steel of the casting.

[0013] Further, in step S2, the product of the second preset length and the preset coefficient is calculated, and the working modes of the first flow control roller and the third flow control roller are determined based on the comparison result of the first preset length and the product, wherein the preset coefficient is 1.5.

[0014] Furthermore, in the step S4, it includes:

[0015] Step S41, judging whether it is necessary to adjust the temperature of the single ingot according to the first characteristic of the surface temperature curve of the single ingot;

[0016] Step S42, when it is determined that temperature adjustment is required, judging whether to adjust the flow state of the molten steel according to the second characteristic of the surface temperature curve of each ingot;

[0017] The ingot surface temperature curve is a temperature variation curve generated by detecting a single detection point on the ingot surface according to a time sequence process.

[0018] Further, in the step S41, the determining whether the temperature of the ingot needs to be adjusted includes:

[0019] Step S411, dividing the surface temperature curve of the casting into a plurality of temperature curve segments, each temperature curve segment is determined according to the temperature slope value or temperature value at the detection point;

[0020] Step S412, calculating the first characteristic based on the duration of each temperature curve segment, and determining whether the temperature of the ingot needs to be adjusted based on the first characteristic.

[0021] Furthermore, in step S411, dividing each temperature curve segment includes:

[0022] Determining segment points of the temperature curve segments on the surface temperature curve of the casting billet based on a preset temperature slope interval to determine each temperature curve segment;

[0023] Determine the temperature curve segment based on the time point corresponding to the current temperature value and the time point determined by the temperature value on the surface temperature curve of the casting billet that meets the preset maximum temperature difference;

[0024] The temperature curve segment is determined based on the continuous time length of time that each temperature value on the surface temperature curve of the casting billet exceeds a preset temperature value.

[0025] Further, in step S42, when it is determined that the temperature of the ingot needs to be adjusted, the absolute value of the difference between the temperature at each time temperature monitoring point on the corresponding temperature curve segment and the preset temperature is calculated, and based on the number of monitoring points whose absolute value of the difference is greater than or equal to the preset temperature difference, it is determined whether the flow state of the molten steel needs to be adjusted, wherein:

[0026] If the number of monitoring points is greater than or equal to the preset number of monitoring points, it is determined that the flow state of the molten steel needs to be adjusted.

[0027] Furthermore, in step S5, when it is determined that the flow state of the molten steel needs to be adjusted, the adjustment object is determined according to the point distribution of each detection point corresponding to each temperature curve segment, and the adjustment method of the flow state of the molten steel is determined according to the adjustment object and the number of points of each detection point;

[0028] Wherein, the adjustment object includes the brake roller and the traveling roller.

[0029] Further, in step S5, when it is determined that the flow state of the molten steel needs to be adjusted, if the total number of the detection points corresponding to each temperature curve segment is less than or equal to the preset number of points, and the detection points are located at the brake roller position, it is determined that the central flow rate of the molten steel needs to be adjusted; if the detection points are located at the traveling roller position, it is determined that the molten steel winding length or the molten steel winding strength needs to be adjusted;

[0030] If the number of detection points corresponding to each temperature curve segment is greater than the preset number of points, it is determined that the circling direction of the molten steel is adjusted.

[0031] Further, in the step S5, the adjustment parameters of the flow control rollers include the distance between the first flow control roller and the third flow control roller, the working mode, and the current intensity of the brake roller and the traveling roller.

[0032] Further, in step S6, judging whether the adjustment of the flow state of the molten steel is qualified includes:

[0033] Based on the comparison between the height difference of the molten steel surface before and after the adjustment and the preset height difference, it is judged whether the adjustment of the flow state of the molten steel is qualified;

[0034] Based on the comparison between the fluctuation amplitude of the adjusted molten steel level height and the preset fluctuation amplitude, it is judged whether the adjustment of the molten steel flow state is qualified.

[0035] Compared with the prior art, the beneficial effects of the present invention are that the flow control method for a roller electromagnetic stirring device of the present invention comprehensively judges whether to adjust the flow state of the molten steel through the first feature and the second feature, thereby ensuring the accuracy of the adjustment judgment of the flow state of the molten steel, and dividing the temperature curve segments according to the slope, maximum temperature difference and temperature of the surface temperature curve of the ingot, thereby achieving the completeness of the temperature curve segments to be analyzed; the adjustment object is determined by the point distribution of each detection point corresponding to each temperature curve segment, so that the flow state adjustment method corresponding to the adjustment object is subsequently adopted, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel; by comparing the total number of points of each detection point corresponding to each temperature curve segment with the number of preset points, and based on the position of each detection point, the multiple adjustment parameters of the flow control roller are adjusted to adjust the flow state accordingly, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel; by the difference between the liquid level of the molten steel before and after the adjustment and the fluctuation amplitude of the liquid level of the molten steel after the adjustment, it is comprehensively judged whether the adjustment of the flow state of the molten steel is qualified, thereby ensuring the effectiveness of the adjustment of the flow state of the molten steel, and proving the feasibility of the flow control method for a roller electromagnetic stirring device of the present invention.

[0036] Furthermore, the present invention avoids the situation where the first preset length is too large, resulting in the inability to timely control and adjust the flow state of the molten steel during the stirring process, causing unstable flow state and flow velocity, uneven steel liquid composition and surface defects of the casting, or the first preset length is too small, resulting in the molten steel being easy to flow out near the edge of the ingot, and the stability of the flow state cannot be guaranteed when the molten steel is just injected, resulting in overflow of the molten steel, and the working mode of the first flow control roller and the third flow control roller are determined by the first preset length and the second preset length, and the molten steel winding direction is determined, so that the molten steel flow state can be adjusted in this molten steel winding direction later, laying a foundation for adjusting the molten steel flow state.

[0037] Furthermore, the present invention judges the temperature adjustment of the ingot based on the first characteristic of the ingot surface temperature curve, and judges whether to adjust the flow state of the molten steel based on the second characteristic, thereby improving the accuracy of the judgment on the adjustment of the flow state of the molten steel.

[0038] Furthermore, the present invention clarifies the analysis object and provides a basis for temperature judgment analysis by dividing the temperature curve segments into several segments according to the temperature slope value or the temperature value at the detection point, so as to further analyze and calculate the first characteristic of each temperature curve segment to determine whether the temperature of the ingot needs to be adjusted. This avoids the situation where the original temperature curve segment is "divided into two" by dividing the temperature curve segment and then analyzing the slope value or the temperature value, resulting in an incomplete and inaccurate calculated first characteristic, which affects the determination of whether the temperature of the ingot needs to be adjusted. This ensures the accuracy of the determination of the temperature adjustment and further improves the accuracy of the determination of the adjustment of the flow state of the molten steel.

[0039] Furthermore, the present invention divides the temperature curve segments according to the slope of the billet surface temperature curve, the maximum temperature difference and the temperature, and subsequently performs corresponding adjustments on the billet that needs temperature adjustment according to preset values, thereby avoiding dividing the temperature curve segments only by a single judgment criterion among the slope of the billet surface temperature curve, the maximum temperature difference and the temperature, which results in omission of division due to a single judgment criterion not satisfying the temperature adjustment conditions, thereby improving the accuracy of subsequent temperature adjustment judgments and further improving the accuracy of adjustment judgments on the flow state of the molten steel.

[0040] Furthermore, the present invention determines whether to adjust the flow state of the molten steel through the second feature, and further screens the detection points corresponding to the flow state of the molten steel that need to be adjusted to determine the objects that need flow state adjustment, thereby eliminating the situation where the flow state is mistakenly judged to need to be adjusted to affect the entire circulation state of the surrounding molten steel due to actual conditions such as the molten steel temperature suddenly rising only in a certain period of time and the number of monitoring points being less than the preset number of monitoring points, thereby ensuring the stability and accuracy of judging whether to adjust the flow state.

[0041] Furthermore, the present invention determines the adjustment object through the point distribution of each detection point corresponding to each temperature curve segment, so as to subsequently adopt the flow state adjustment method corresponding to the adjustment object, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel.

[0042] Furthermore, the present invention compares the total number of detection points corresponding to the temperature curve segments with the preset number of points, and based on the position of each detection point, takes corresponding steel adjustment methods for the temperature state of the molten steel, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel, and improving the flexibility and comprehensiveness of the flow control method of the roller electromagnetic stirring device of the present invention, so as to obtain molten steel with a temperature that meets the production requirements, so as to facilitate the subsequent production and processing of the molten steel.

[0043] Furthermore, the present invention improves the flexibility and comprehensiveness of the flow control method of the present invention for the roller electromagnetic stirring device by adjusting the multiple adjustment parameters of the flow control roller to control the flow state of the molten steel according to the actual molten steel temperature, flow state and adjustment object, so as to obtain molten steel with a temperature that meets the production requirements, so as to facilitate the subsequent production and processing of the molten steel.

[0044] Furthermore, the present invention comprehensively judges whether the adjustment of the flow state of the molten steel is qualified through the difference in the height of the molten steel level before and after the adjustment and the fluctuation amplitude of the molten steel level after the adjustment, thereby avoiding the situation where only one of the judgment criteria is met while ignoring the other judgment criteria, resulting in an unqualified adjustment of the flow state of the molten steel being misjudged as qualified. The adjustment of the flow state of the molten steel is doubly verified, thereby ensuring the effectiveness of the adjustment of the flow state of the molten steel, and proving the feasibility of the flow control method of the present invention for a roller electromagnetic stirring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The flowchart of the flow control method for a roller-type electromagnetic stirring device according to an embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of the position of a roller-type electromagnetic stirring device according to a specific embodiment of the present invention;

[0047] Figure 3 It is a schematic diagram of the arrangement of a roller-type electromagnetic stirring device according to a specific embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the structure of the flow control roller according to an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the flow control principle of an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of a first embodiment of the present invention;

[0051] Figure 7 This is a schematic diagram of a second embodiment of the present invention;

[0052] Among them: 1. the first flow control roller; 2. the second flow control roller; 3. the third flow control roller; 4. the free clamping roller; 5. the water inlet; 6. the casting; 7. the outlet box; 8. the bearing cover; 9. the bearing seat; 10. the bearing; 11. the first wavy roller; 12. the second wavy roller; 13. the brake roller; 14. the main shaft; 15. the coil; 16. the roller sleeve; 17. the crystallizer copper plate. DETAILED DESCRIPTION

[0053] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0055] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0056] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] See also Figure 1 As shown, it is a working flow chart of a flow control method for a roller-type electromagnetic stirring device according to an embodiment of the present invention. An embodiment of the present invention provides a flow control method for a roller-type electromagnetic stirring device, comprising:

[0058] Step S1, symmetrically arranging a plurality of flow control rollers on two wide surfaces of the casting billet, including a first flow control roller 1 and a third flow control roller 3, and setting the length of the first flow control roller 1 from the edge of the casting billet near the water inlet 5 to a first preset length, and setting the length of a single waving roller in the flow control rollers to a second preset length; wherein the single flow control roller comprises a brake roller 13 arranged in the middle section of the roller body and two waving rollers respectively arranged at both ends of the roller body;

[0059] Step S2, determining the working mode of the first flow control roller 1 and the third flow control roller 3 according to the first preset length, the second preset length and the preset coefficient; wherein the working mode includes an internal push mode and an external push mode;

[0060] Step S3, when the molten steel is introduced into the ingot 6 through the water inlet 5, the temperature and the height of the molten steel level at a plurality of detection points between the first flow control roller 1 and the third flow control roller 3 are detected, wherein the plurality of detection points are arranged in an array on two wide surfaces of the ingot;

[0061] Step S4, judging whether the flow state of the molten steel needs to be adjusted according to the characteristics of the surface temperature curve of the ingot;

[0062] Step S5, based on the judgment result, determining the adjustment method of the flow state of the molten steel, and determining the adjustment parameters of the flow control roller, the adjustment method of the flow state of the molten steel includes adjusting the central flow velocity of the molten steel, adjusting the molten steel winding length, adjusting the molten steel winding strength and adjusting the molten steel winding direction, wherein the central flow velocity is determined by the magnetic field strength generated by the brake roller 13, the molten steel winding length is determined by the spacing between the first flow control roller 1 and the third flow control roller 3, the molten steel winding strength is determined by the magnetic field strength generated by the traveling wave roller, and the molten steel winding direction is determined by the working mode of the first flow control roller 1 and the third flow control roller 3;

[0063] Step S6, judging whether the adjustment of the flow state of the molten steel is qualified based on the change of the liquid level of the molten steel before and after the adjustment;

[0064] Step S7, repeating steps S3-S6 to continuously monitor the flow state of molten steel of the casting.

[0065] See also Figure 2-Figure 4 As shown, Figure 2 This is a schematic diagram of the position of a roller-type electromagnetic stirring device according to a specific embodiment of the present invention. Figure 3 This is a schematic diagram of the arrangement of a roller-type electromagnetic stirring device according to a specific embodiment of the present invention. Figure 4 It is a schematic structural diagram of a flow control roller according to an embodiment of the present invention.

[0066] Specifically, see Figure 4 The single flow control roller of this embodiment mainly includes: an outlet box 7, a bearing cover 8, a bearing seat 9, a bearing 10, a first wavy roller 11, a second wavy roller 12, a brake roller 13, a main shaft 14, a coil 15, and a roller sleeve 16; the first wavy roller 11 and the second wavy roller 12 are symmetrically arranged on both sides of the brake roller 13, wherein the wavy roller mainly provides a lateral electromagnetic thrust along the wide surface of the ingot for the unsolidified liquid core, and the brake roller 13 is used to control the flow rate of the liquid core in the middle of the electromagnetic flow control roller along the direction of the billet drawing; the wavy roller and the brake roller 13 are connected at both ends by bearings 10, and the bearings 10 and the bearing seat 9 can improve the working strength of the electromagnetic flow control roller.

[0067] In practice, the flow control rollers replace the free clamping rollers 4 on the thin slab continuous casting machine and are installed in pairs on the continuous casting machine segments. It is possible to flexibly install a pair of rollers or two pairs of rollers separately or in combination. Depending on the installation position of the flow control rollers and the number of roller pairs used in combination, the flow field of the molten steel generated by the flow control rollers in the casting is different, and the final metallurgical effect is also different.

[0068] It is understandable that the second flow control roller 2 can be equipped according to actual needs and can be arranged in parallel with the first flow control roller 1 to play an auxiliary flow control role. Whether it is equipped or not falls within the protection scope of the present invention.

[0069] See also Figure 2 and Figure 3 As shown, in a specific embodiment, a second flow control roller 2 is provided.

[0070] In this embodiment, in order to prevent the temperature of the ingot from rising again after temperature dissipation to generate secondary columnar crystals, a third flow control roller 3 is symmetrically arranged on the wide surface of the ingot within a range of 1 meter to 2 meters from the first flow control roller 1.

[0071] Please refer to Figure 5 As shown, it is a schematic diagram of the flow control principle of an embodiment of the present invention.

[0072] The first wavy roller 11 and the second wavy roller 12 generate electromagnetic forces F1 and F2 parallel to the wide surface of the ingot, which promote the formation of a molten steel circulation inside the ingot in the same direction as the electromagnetic force, wherein the flow velocity in the middle of the circulation is added to the flow velocity in the water gate, resulting in an excessively fast flow velocity in the middle. Therefore, a brake roller 13 is arranged in the middle of the flow control roller to prevent the flow drum from impacting too deeply on the one hand and to disperse the concentrated intermediate circulation on the other hand, thereby enhancing the uniform dispersion of components and heat in the molten steel.

[0073] In this embodiment, two first flow control rollers 1 and two third flow control rollers 3 are symmetrically arranged on two wide surfaces of the casting billet, and the length of a single first flow control roller from the edge of the casting billet close to the water inlet is a first preset length.

[0074] See also Figure 6 and Figure 7 As shown, it can be understood that the flow speed and flow direction of the molten steel can be adjusted by adjusting the parameters of the flow control roller. During the casting process, the flow control roller can push or guide the molten steel to a specific area by pushing inward or outward.

[0075] The brake roller 13 has a braking effect on the molten steel, and the traveling wave roller has a driving effect on the molten steel, both of which are achieved by generating an electromagnetic force on the molten steel by a magnetic field generated by passing current.

[0076] The first flow control roller 1 and the third flow control roller 3 pass current to generate a magnetic field, electromagnetically stir the molten steel, drive the molten steel to move and mix it evenly, improve the overall fluidity of the molten steel, and help to even out the temperature distribution.

[0077] In this embodiment, in order to solve the internal quality problem of the ingot caused by the high drawing speed, multiple pairs of flow control rollers are provided on the wide surface of the ingot to improve the flow of molten steel inside the ingot and reduce temperature dissipation, and the flow control rollers need to be installed in the casting zone. Therefore, the first flow control roller 1 is installed under the crystallizer copper plate 17 to dissipate the heat of the high-temperature molten steel passing through the crystallizer copper plate 17 as soon as possible.

[0078] The flow control method for a roller electromagnetic stirring device of the present invention comprehensively judges whether to adjust the flow state of the molten steel through the first feature and the second feature, thereby ensuring the accuracy of the adjustment judgment of the flow state of the molten steel, and dividing the temperature curve segments according to the slope of the surface temperature curve of the ingot, the maximum temperature difference and the temperature, thereby achieving the completeness of the temperature curve segments to be analyzed; the adjustment object is determined by the point distribution of each detection point corresponding to each temperature curve segment, so that the flow state adjustment method corresponding to the adjustment object is subsequently adopted, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel; by comparing the total number of points of each detection point corresponding to each temperature curve segment with the number of preset points, and based on the position of each detection point, the multiple adjustment parameters of the flow control roller are adjusted to adjust the flow state accordingly, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel; by the difference between the liquid level of the molten steel before and after the adjustment and the fluctuation amplitude of the liquid level of the molten steel after the adjustment, it is comprehensively judged whether the adjustment of the flow state of the molten steel is qualified, thereby ensuring the effectiveness of the adjustment of the flow state of the molten steel, and proving the feasibility of the flow control method for a roller electromagnetic stirring device of the present invention.

[0079] See also Figure 6 and Figure 7 As shown, Figure 6 This is a schematic diagram of a first embodiment of the present invention. Figure 7 This is a schematic diagram of the second embodiment of the present invention.

[0080] Specifically, in step S2, the product of the second preset length and the preset coefficient is calculated, and the working mode of the first flow control roller 1 and the third flow control roller 3 is determined based on the comparison result of the first preset length and the product, wherein the preset coefficient is 1.5.

[0081] It can be understood that the working modes of the first flow control roller 1 and the third flow control roller 3 include internal pushing and external pushing.

[0082] like Figure 6 and Figure 7 As shown, in this embodiment, if the first preset length is less than the product, it is determined to adopt mode one, that is, the first flow control roller 1 adopts the inner push mode, and the third flow control roller 3 adopts the outer push mode; if the first preset length is greater than or equal to the product, it is determined to adopt mode two, that is, the first flow control roller 1 adopts the outer push mode, and the third flow control roller 3 adopts the inner push mode.

[0083] It is understandable that before pouring the molten steel, it is necessary to control the length of the first flow control roller 1 from the edge of the ingot near the water inlet 5 and the length of the wavy roller. If the first preset length is too small compared to the product, the molten steel will easily flow out near the edge of the ingot, and the stability of the flow state cannot be guaranteed when the molten steel is just injected, resulting in overflow of the molten steel.

[0084] If the first preset length is too large compared to the product, that is, the first flow control roller 1 is too far away from the water inlet 5, the flow state of the molten steel cannot be controlled and adjusted in time during the stirring process, resulting in unstable flow state of the molten steel, uneven composition of the molten steel and surface defects of the casting.

[0085] In this embodiment, L is the second preset length, H1 is the first preset length, the preset coefficient is 1.5, and the first preset length is 0.8m

[0086] Mode 1: If H1<1.5*L, it is determined that the first flow control roller 1 adopts the inner push mode and the third flow control roller 3 adopts the outer push mode.

[0087] It can be understood that when the first flow control roller 1 is pushed inward, the first flow control roller 1 is installed forward on the ingot 6, which is beneficial to stirring the flow of molten steel and dissipating the core temperature of the molten steel as soon as possible.

[0088] Because the two wave rollers of the first flow control roller 1 push the molten steel to flow to the middle area, collide with each other and flip upward, forming a single strand of ingot steel liquid flow, and the molten steel at the sprue flows downward to form a single sprue steel liquid flow, the two molten steel flows form opposite convection, and the molten steel liquid level is braked to cause fluctuations; therefore, a weak current or no current is passed through the brake roller 13 of the first flow control roller 1; the third flow control roller 3 adopts an extrapolation mode to form two closed rotating circulation flows with the first flow control roller 1, to ensure that the molten steel in the middle area of ​​the two flow control rollers is circulated and rotated and stirred, to avoid overheating of the molten steel between the two flow control rollers, and the flows are mainly concentrated in the middle area and impact downward, to avoid slag inclusions from impacting too deeply, a large current is passed through the brake roller 13 of the third flow control roller 3.

[0089] In this embodiment, the current passed through the first current control roller 1 ranges from 100A to 400A, and the current passed through the third current control roller 3 is greater than 500A.

[0090] Mode 2: If H1≥1.5*L, it is determined that the first flow control roller 1 adopts the extrapolation mode and the third flow control roller 3 adopts the inner push mode. In this embodiment, the first preset length is 1.5m

[0091] ​​It can be understood that, since the first flow control roller 1 adopts the push-out mode, the molten steel has enough flow space, and the two wave rollers push the molten steel to merge with the molten steel at the water inlet downward, so a large current is passed through the brake roller 13 of the first flow control roller 1 to prevent the deep impact of the molten steel from causing the slag inclusions to impact too deeply, which is not conducive to the floating and removal of the inclusions; the third flow control roller 3 adopts the push-in mode to form two closed rotating circulation flows with the first flow control roller 1, to ensure that the molten steel in the middle area of ​​the two flow control rollers is circulated and rotated and stirred, to avoid overheating of the molten steel between the two flow control rollers, and the molten steel flow is mainly concentrated in the middle to impact downward. In order to prevent the slag inclusions from impacting too deeply, a large current is also passed through the brake roller 13 of the third flow control roller 3.

[0092] In this embodiment, the input current of the first current control roller 1 and the third current control roller 3 is greater than 500A.

[0093] It can be understood that the first flow control roller 1 on the continuous casting machine needs to be set at a reasonable distance from the liquid surface. The first flow control roller 1 adopts an outward push mode to allow the flow strand to have enough flow space; the third flow control roller 3 adopts an inward push mode to ensure that the molten steel in the middle area between the two flow control rollers is circulated and rotated and stirred to avoid overheating of the molten steel between the two flow control rollers.

[0094] The present invention avoids the situation that the first preset length is too large, which leads to the inability to timely control and adjust the flow state of the molten steel during the stirring process, resulting in unstable flow state of the molten steel, uneven composition of the molten steel and surface defects of the casting, or the first preset length is too small, which leads to the molten steel flowing out easily near the edge of the ingot, and the stability of the flow state cannot be guaranteed when the molten steel is just injected, resulting in overflow of the molten steel. The working mode of the first flow control roller and the third flow control roller are determined by the first preset length and the second preset length, and the molten steel winding direction is determined, so that the flow state of the molten steel can be adjusted in this molten steel winding direction later, laying a foundation for adjusting the flow state of the molten steel.

[0095] Specifically, in step S4, it includes:

[0096] Step S41, judging whether it is necessary to adjust the temperature of the casting 6 according to the first characteristic of the surface temperature curve of the single casting;

[0097] Step S42, when it is determined that temperature adjustment is required, judging whether to adjust the flow state of the molten steel according to the second characteristic of the surface temperature curve of each ingot;

[0098] The ingot surface temperature curve is a temperature variation curve generated by detecting a single detection point on the ingot surface according to a time sequence process.

[0099] It can be understood that the temperature of the ingot 6 is an important indicator for determining whether to adjust the flow state of the molten steel. The performance of the cast part is closely related to the temperature during the casting process. Before determining whether to adjust the flow state of the molten steel, it is necessary to determine whether to adjust the temperature of the ingot 6.

[0100] The method of judging whether the temperature of the ingot 6 needs to be adjusted is different from that of judging whether the flow state of the molten steel needs to be adjusted, and the contents to be compared are different, so different features need to be selected for judgment. In this embodiment, judgment is made based on the first feature and the second feature respectively.

[0101] The present invention judges the temperature adjustment of the ingot according to the first characteristic of the ingot surface temperature curve, and judges whether to adjust the flow state of the molten steel according to the second characteristic, thereby improving the accuracy of the judgment on the adjustment of the flow state of the molten steel.

[0102] Specifically, in step S41, the determination of whether the temperature of the ingot 6 needs to be adjusted includes:

[0103] Step S411, dividing the surface temperature curve of the casting into a plurality of temperature curve segments, each temperature curve segment is determined according to the temperature slope value or temperature value at the detection point;

[0104] Step S412: Calculate the first feature based on the duration of each temperature curve segment, and determine whether the temperature of the ingot 6 needs to be adjusted based on the first feature.

[0105] In this embodiment, the division method, duration, corresponding value, etc. of each temperature curve segment are different, and each temperature curve segment is independent of each other and has no common points.

[0106] After dividing the temperature curve into several segments, each temperature curve segment needs to be analyzed separately, and the corresponding first characteristics are calculated based on the duration corresponding to each temperature curve segment, and based on each first characteristic, it is comprehensively judged whether the temperature of the ingot 6 needs to be adjusted.

[0107] The present invention clarifies the analysis object and provides a basis for temperature judgment analysis by dividing a plurality of temperature curve segments according to the temperature slope value or the temperature value at the detection point, so as to further analyze and calculate the first characteristic of each temperature curve segment to determine whether the temperature of the ingot needs to be adjusted. This avoids the situation that the original temperature curve segment is "divided into two" by dividing the temperature curve segment and then analyzing the slope value or the temperature value, resulting in an incomplete and inaccurate calculated first characteristic, which affects the determination of whether the temperature of the ingot needs to be adjusted. This ensures the accuracy of the determination of the temperature adjustment and further improves the accuracy of the determination of the adjustment of the flow state of the molten steel.

[0108] Specifically, in step S411, each temperature curve segment is divided into:

[0109] Determining segment points of the temperature curve segments on the surface temperature curve of the casting billet based on a preset temperature slope interval to determine each temperature curve segment;

[0110] Determine the temperature curve segment based on the time point corresponding to the current temperature value and the time point determined by the temperature value on the surface temperature curve of the casting billet that meets the preset maximum temperature difference;

[0111] The temperature curve segment is determined based on the continuous time length of time that each temperature value on the surface temperature curve of the casting billet exceeds a preset temperature value.

[0112] In this embodiment, dividing each temperature curve segment includes:

[0113] If the slopes of several consecutive time-series temperature monitoring points on the surface temperature curve of the casting billet are not within the range of the preset temperature slope, the initial point and the end point of the corresponding consecutive time-series temperature monitoring points according to the time-series process are used as the segmentation points of the temperature curve segment, and the curve segment formed by closing the segmentation points on the surface temperature curve of the casting billet is used as a single temperature curve segment;

[0114] If the current temperature values ​​corresponding to the time points at several consecutive time-series temperature monitoring points of the continuous curve segment on the surface temperature curve of the casting billet are not within the time point range determined by the temperature value that meets the preset maximum temperature difference on the surface temperature curve of the casting billet, the continuous curve segment is regarded as a single temperature curve segment;

[0115] If the temperature values ​​at several consecutive time-series temperature monitoring points on the surface temperature curve of the casting blank exceed the preset temperature value, the curve segment on the surface temperature curve of the casting blank corresponding to the maximum continuous time length for which the temperature value exceeds the preset temperature value is taken as a single temperature curve segment;

[0116] The plurality of sequential temperature monitoring points are a plurality of analysis points selected according to the sequential process on the surface temperature curve of the casting blank of a single monitoring point.

[0117] It can be understood that the numerical value of the slope of the ingot surface temperature curve is equal to the ingot surface temperature change rate, and the ingot surface temperature change rate is the amount of change in the ingot surface temperature within a preset time length. The preset time length is determined based on actual production and actual requirements, and the value should be as small as possible to obtain the accurate ingot surface temperature change rate and slope, thereby improving the accuracy of determining the surface temperature curve.

[0118] In this embodiment, the preset time length is 2s to 5s.

[0119] It can be understood that the value of the preset temperature slope is equal to the preset temperature change rate, and the preset temperature change rate is determined according to actual production requirements.

[0120] In this embodiment, the preset temperature change rate is in the range of 2°C / s to 10°C / s, and thus the preset temperature slope is in the range of 2°C / s to 10°C / s.

[0121] It can be understood that the preset maximum temperature difference is determined according to factors such as actual material, casting process, mold design and product size.

[0122] In this embodiment, the preset maximum temperature difference is 10°C to 50°C.

[0123] It can be understood that the preset temperature is determined according to the standard stirring temperature of the molten steel in the ingot 6, and the standard stirring temperature is determined according to the composition of the molten steel in actual production, actual production requirements, etc.

[0124] In this embodiment, the standard stirring temperature of the molten steel is in the range of 1500°C to 1800°C, and the preset temperature is also in the range of 1500°C to 1800°C.

[0125] In this embodiment, whether the temperature of the ingot 6 needs to be adjusted is determined based on the first feature, that is, if the temperature curve segment lasts for a certain period of time, it is determined whether the temperature of the ingot 6 needs to be adjusted, so as to avoid unexpected situations such as sudden increase or decrease in temperature, and erroneous judgment that temperature adjustment and molten steel flow state are required, and other unnecessary adjustments, which lead to the destruction of the original balanced and uniform state of the molten steel temperature flow state.

[0126] The first feature is a comparison result of the duration of each temperature curve segment and the corresponding preset duration.

[0127] It can be understood that if the duration of the temperature curve segment in the first feature is greater than the corresponding preset duration, it is determined that the temperature of the casting slab 6 needs to be adjusted.

[0128] In this embodiment, the comparison result between the duration of the temperature curve segment determined based on the preset temperature slope and the first preset duration is used as the first feature, and whether the temperature of the casting 6 needs to be adjusted is determined according to the first feature; if the duration is greater than or equal to the first preset duration, it is determined that the temperature of the casting 6 needs to be adjusted; if the duration is less than the first preset duration, it is determined that the temperature of the casting 6 does not need to be adjusted;

[0129] A comparison result between the duration of the temperature curve segment determined based on the preset maximum temperature difference and the second preset duration is used as a first feature, and whether the temperature of the ingot 6 needs to be adjusted is determined according to the first feature; if the duration is greater than or equal to the second preset duration, it is determined that the temperature of the ingot 6 needs to be adjusted; if the duration is less than the second preset duration, it is determined that the temperature of the ingot 6 does not need to be adjusted;

[0130] The comparison result of the duration of the temperature curve segment determined based on the preset temperature value and the third preset duration is used as the first feature, and whether the temperature of the ingot 6 needs to be adjusted is determined based on the first feature; if the duration is greater than or equal to the third preset duration, it is determined that the temperature of the ingot 6 needs to be adjusted; if the duration is less than the third preset duration, it is determined that the temperature of the ingot 6 does not need to be adjusted.

[0131] It can be understood that the flow rate of the molten steel is inversely proportional to the first preset time, the second preset time and the third preset time, that is, the greater the flow rate of the molten steel, the smaller the values ​​of the first preset time, the second preset time and the third preset time should be. Therefore, the first preset time, the second preset time and the third preset time are adjusted according to the flow rate of the molten steel in the ingot 6 to ensure the accuracy of the judgment on whether the temperature of the ingot 6 is adjusted.

[0132] In this embodiment, the first preset time length, the second preset time length, and the third preset time length all have a value range of 2s to 10s.

[0133] If the first characteristic lasts longer than the first preset time, it may cause a sudden temperature change due to excessive flow rate, leading to casting defects, uneven microstructure, degradation of mechanical properties, deformation and shrinkage problems. Therefore, it is necessary to adjust the temperature of the ingot 6 to reduce the turbulence and heat exchange rate of the molten steel. By controlling the slope at several points on the ingot surface temperature curve, that is, the temperature change rate during the casting process is within a reasonable range, the quality, performance and stability of the casting and subsequent processing are ensured, the production cost is reduced and the production efficiency is improved.

[0134] If the first characteristic lasts longer than the second preset time, it proves that the temperature distribution of various parts of the molten steel is uneven, resulting in internal defects, surface defects, degradation of physical properties and uneven distribution of components in the cast castings; in order to ensure the best casting effect, the temperature of the ingot 6 needs to be adjusted to improve the quality and availability of the castings.

[0135] If the first characteristic lasts for a period longer than the third preset period, it may cause thermal cracks, pores and inclusions, microstructural problems, degradation of mechanical properties, deformation and shrinkage problems, etc., affecting the quality and performance of the casting and increasing production costs and risks. Therefore, it is necessary to adjust the temperature of the ingot 6 to control the temperature during the casting process to ensure that the casting is produced within a reasonable temperature range.

[0136] The present invention divides the temperature curve segments according to the slope of the billet surface temperature curve, the maximum temperature difference and the temperature, and subsequently performs corresponding adjustments on the billet that needs temperature adjustment according to preset values, thereby avoiding dividing the temperature curve segments only by a single judgment criterion among the slope of the billet surface temperature curve, the maximum temperature difference and the temperature, which results in omission of division due to a single judgment criterion not satisfying the temperature adjustment condition, thereby improving the accuracy of subsequent temperature adjustment judgment and further improving the accuracy of adjustment judgment on the flow state of molten steel.

[0137] Specifically, in step S42, when it is determined that the temperature of the ingot 6 needs to be adjusted, the absolute value of the difference between the temperature at each time temperature monitoring point on the corresponding temperature curve segment and the preset temperature is calculated, and based on the number of monitoring points whose absolute value of the difference is greater than or equal to the preset temperature difference, it is determined whether the flow state of the molten steel needs to be adjusted, wherein:

[0138] If the number of monitoring points is greater than or equal to the preset number of monitoring points, it is determined that the flow state of the molten steel needs to be adjusted.

[0139] It is understandable that if the number of monitoring points is less than the preset number of monitoring points, there is no need to adjust the flow state of the molten steel.

[0140] It can be understood that the second feature is the comparison result between the number of temperature monitoring points in each time sequence and the number of preset monitoring points when judging whether to adjust the flow state of the molten steel.

[0141] In this embodiment, if the difference between the temperature at several points on the surface temperature curve of the ingot and the preset temperature is greater than or equal to the preset temperature difference, the temperature of the ingot 6 can be quickly adjusted by adjusting the flow rate of the molten steel, which will not affect the normal casting process or will have little impact, and will not affect the quality and performance of the casting.

[0142] If the absolute value of the difference between the temperature at several points on the surface temperature curve of the ingot and the preset temperature is less than the preset temperature difference, the temperature of the ingot 6 can be changed by directly heating and cooling the ingot 6, and the flow state of the original molten steel will not be destroyed due to adjusting the flow rate of the molten steel. When the flow rate of the molten steel is adjusted to adjust the temperature of the ingot 6, compared with direct heating and cooling, the adjustment is inflexible and the time is slow, and the temperature of the ingot 6 cannot be reduced in time, resulting in thermal cracks, pores and inclusions, microstructural problems, mechanical property degradation, deformation and shrinkage problems, etc., which affect the quality and performance of the casting, affect the normal casting process, and increase production costs and risks. At this time, it is necessary to ensure the reasonable temperature of the casting process and the quality and performance of the casting.

[0143] The present invention determines whether to adjust the flow state of the molten steel through the second feature, and further screens the detection points corresponding to the flow state of the molten steel that need to be adjusted to determine the objects that need flow state adjustment, thereby eliminating the situation where the flow state is mistakenly judged to need to be adjusted to affect the entire circulation state of the surrounding molten steel due to actual conditions such as the temperature of the molten steel suddenly rising only in a certain period of time and the number of monitoring points being less than the preset number of monitoring points, thereby ensuring the stability and accuracy of judging whether to adjust the flow state.

[0144] Specifically, in step S5, when it is determined that the flow state of the molten steel needs to be adjusted, the adjustment object is determined according to the point distribution of each detection point corresponding to each temperature curve segment, and the adjustment method of the flow state of the molten steel is determined according to the adjustment object and the number of points of each detection point;

[0145] The adjustment object includes the brake roller 13 and the traveling roller.

[0146] It can be understood that a single ingot surface temperature curve corresponds to a single detection point, and the temperature curve segment is a part of the ingot surface temperature curve. Therefore, when judging whether the flow state of the molten steel needs to be adjusted based on the characteristics of the ingot surface temperature curve, the position of the monitoring point corresponding to the temperature curve segment needs to be used as the object for judging whether the flow state of the molten steel needs to be adjusted.

[0147] By adjusting the flow state of the molten steel and then adjusting the temperature of the ingot 6, the temperature of the molten steel is made uniform and within a reasonable pouring temperature range, so as to ensure a reasonable temperature during the casting process and the quality and performance of the casting.

[0148] The present invention determines the adjustment object through the point distribution of each detection point corresponding to each temperature curve segment, so as to subsequently adopt the flow state adjustment method corresponding to the adjustment object, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the molten steel.

[0149] Specifically, in step S5, when it is determined that the flow state of the molten steel needs to be adjusted, if the total number of detection points corresponding to each temperature curve segment is less than or equal to the preset number of detection points, and the detection points are located at the brake roller position, it is determined that the central flow rate of the molten steel needs to be adjusted; if the detection points are located at the traveling roller position, it is determined that the molten steel winding length or the molten steel winding strength needs to be adjusted;

[0150] It is understood that the brake roller position is Figure 6 The position of the traveling roller is at the steel liquid circulation Y near the corresponding brake roller 13 on the casting billet 6. Figure 6 The steel liquid circulation X is located near the corresponding traveling roller on the casting billet 6.

[0151] If the number of detection points corresponding to each temperature curve segment is greater than the preset number of points, it is determined that the circling direction of the molten steel is adjusted.

[0152] It can be understood that the number of preset points is determined according to the number of temperature detection points in actual production and is smaller than the number of temperature detection points in actual production, so as to distinguish and determine the adjustment method for the flow state of the molten steel.

[0153] In a specific embodiment, the total number of the detection points is 20, and the number of the preset points is 5.

[0154] In this embodiment, if it is determined that the number of points corresponding to the need to adjust the flow state of the molten steel is less than or equal to the preset number of points, corresponding adjustments are made according to different adjustment objects: adjusting the central flow velocity, that is, adjusting the flow state of the molten steel near the brake roller 13; adjusting the molten steel wrapping length or adjusting the molten steel wrapping intensity, that is, adjusting the flow state of the molten steel near the traveling roller.

[0155] If it is determined that the corresponding number of points when the flow state of the molten steel needs to be adjusted is greater than the preset number of points, it proves that the area where the temperature of the ingot 6 is greater than the preset temperature is too large. At this time, the ingot 6 cannot be quickly cooled by adjusting the current of the first flow control roller 1 and / or the third flow control roller 3, and the adjustment efficiency is not high, and repeated adjustments are required. It is then determined to adjust the molten steel's circulation direction, that is, to change the flow direction of the molten steel by adjusting the working mode of the first flow control roller 1 and / or the third flow control roller 3, so as to adjust the flow state of the molten steel and then adjust the molten steel temperature.

[0156] The present invention compares the total number of detection points corresponding to the temperature curve segments with the preset number of points, and based on the position of each detection point, takes a corresponding steel liquid adjustment method for the temperature state of the steel liquid, thereby improving the efficiency and accuracy of adjusting the temperature and flow state of the steel liquid, and improving the flexibility and comprehensiveness of the flow control method of the present invention for the roller electromagnetic stirring device, so as to obtain steel liquid whose temperature meets the production requirements, so as to facilitate the subsequent production and processing of the steel liquid.

[0157] Specifically, in step S5, the adjustment parameters of the flow control rollers include the distance between the first flow control roller 1 and the third flow control roller 3, the working mode, and the current intensity of the brake roller 13 and the traveling roller.

[0158] In this embodiment, the adjustment parameters of the flow control roller are determined according to the adjustment object.

[0159] In this embodiment, the central flow velocity is determined by the magnetic field strength generated by the brake roller 13, the molten steel winding length is determined by the spacing between the first flow control roller 1 and the third flow control roller 3, the molten steel winding strength is determined by the magnetic field strength generated by the traveling wave roller, and the molten steel winding direction is determined by the working modes of the first flow control roller 1 and the third flow control roller 3.

[0160] It can be understood that the magnetic field strength is achieved by controlling the current strength of the brake roller 13 and the traveling roller to adjust the flow rate of the molten steel.

[0161] It can be understood that after determining the adjustment method for the flow state of the molten steel, the flow state of the molten steel is adjusted according to the adjustment parameters of the flow control roller.

[0162] The present invention adjusts the multiple adjustment parameters of the flow control roller to control the flow state of the molten steel according to the actual molten steel temperature, flow state and adjustment object, thereby improving the flexibility and comprehensiveness of the flow control method of the present invention for the roller electromagnetic stirring device, so as to obtain molten steel with a temperature that meets the production requirements, so as to facilitate the subsequent production and processing of the molten steel.

[0163] Specifically, in step S6, judging whether the adjustment of the flow state of the molten steel is qualified includes:

[0164] Based on the comparison between the height difference of the molten steel surface before and after the adjustment and the preset height difference, it is judged whether the adjustment of the flow state of the molten steel is qualified;

[0165] Based on the comparison between the fluctuation amplitude of the adjusted molten steel level height and the preset fluctuation amplitude, it is judged whether the adjustment of the molten steel flow state is qualified.

[0166] It is understandable that if the difference in the height of the molten steel level before and after the adjustment is greater than the preset height difference, it is determined that the adjustment of the flow state of the molten steel is unqualified, and the molten steel flow rate at the nozzle is increased.

[0167] If the fluctuation amplitude of the height of the molten steel level after the adjustment is greater than the preset fluctuation amplitude, it is determined that the adjustment of the flow state of the molten steel is unqualified, and the flow rate of the molten steel at the nozzle is reduced.

[0168] It can be understood that the adjustment of the flow state of the molten steel can be judged to be qualified only when the comprehensive steel liquid level height and the fluctuation amplitude of the steel liquid level height are both judged to be qualified.

[0169] In this embodiment, the preset height difference is the average value of the difference in liquid level height of the molten steel before and after adjustment when the adjustment of the flow state of the molten steel is qualified in all previous actual production; the preset fluctuation amplitude is the difference between the average maximum liquid level height and the average minimum liquid level height in all previous actual production.

[0170] It is understandable that the fluctuation of the molten steel level needs to be reduced during the stirring process. Static fluctuation is generally considered to be the most ideal liquid level fluctuation state to ensure product quality. The reasons are: the fluctuation amplitude is small, the molten steel level will not fluctuate violently, the molten steel will be kept in a stable state, and the risk of splashing and bubble formation will be reduced; under the static fluctuation state, the temperature and fluidity of the molten steel are more uniform, thereby improving the filling quality and density of the casting and reducing the probability of defects such as shrinkage holes, pores and cracks; static fluctuation is usually more conducive to uniform temperature distribution, helps to keep the molten steel within a suitable pouring temperature range, ensures effective temperature control and thermal management of each area, and reduces instability; static fluctuation reduces instability, makes the casting process more controllable, and avoids uneven flow and cooling; under static fluctuation, the molten steel will not cause stress concentration due to violent fluctuations, which helps to avoid uneven stress inside the casting and reduce the possibility of defects in subsequent processing or use.

[0171] Therefore, after adjusting the flow state of the molten steel, the liquid level height of the molten steel and the fluctuation amplitude of the liquid level height need to be detected to ensure that the liquid level height is within the preset height range and the fluctuation amplitude of the liquid level height is within the preset fluctuation amplitude range.

[0172] It is understandable that when the difference between the molten steel level before and after adjustment is greater than the preset height difference, the molten steel flow rate at the sprue needs to be increased to maintain the molten steel level before adjustment to ensure the size and quality of the casting.

[0173] It is understandable that when the fluctuation of the adjusted molten steel level is too large, reducing the molten steel flow rate at the nozzle can reduce the level fluctuation. A slower pouring speed is easier to keep the liquid level stable and avoid violent impacts and fluctuations.

[0174] The present invention comprehensively judges whether the adjustment of the flow state of the molten steel is qualified through the difference between the liquid level heights of the molten steel before and after the adjustment and the fluctuation amplitude of the liquid level height of the molten steel after the adjustment, thereby avoiding the situation where only one of the judgment criteria is met while ignoring the other judgment criteria, resulting in an unqualified adjustment of the flow state of the molten steel being misjudged as qualified. The adjustment of the flow state of the molten steel is doubly verified, thereby ensuring the effectiveness of the adjustment of the flow state of the molten steel, and proving the feasibility of the flow control method of the present invention for a roller electromagnetic stirring device.

[0175] It should be noted that in this article, relational terms such as first and third are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, material or equipment that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, material or equipment.

[0176] Any matters not described in the present invention are applicable to the prior art.

[0177] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A flow control method for a roller type electromagnetic stirring device, characterized in that: include: Step S1, symmetrically arranging a plurality of flow control rollers on two wide surfaces of the casting billet, including a first flow control roller and a third flow control roller, and setting the length of the first flow control roller from the edge of the casting billet close to the water inlet to a first preset length, and setting the length of a single wavy roller in the flow control rollers to a second preset length; wherein the single flow control roller comprises a brake roller arranged in the middle section of the roller body and two wavy rollers respectively arranged at both ends of the roller body; Step S2, determining the working modes of the first flow control roller and the third flow control roller according to the first preset length, the second preset length and the preset coefficient; wherein the working modes include an internal push mode and an external push mode; Step S3, when the molten steel is introduced into the ingot through the water inlet, the temperature and the height of the molten steel level at a plurality of detection points between the first flow control roller and the third flow control roller are detected, wherein the plurality of detection points are arranged in an array on two wide surfaces of the ingot; Step S4, judging whether the flow state of the molten steel needs to be adjusted according to the characteristics of the surface temperature curve of the ingot; Step S5, based on the judgment result, determining the adjustment method of the flow state of the molten steel, and determining the adjustment parameters of the flow control roller, the adjustment method of the flow state of the molten steel includes adjusting the central flow velocity of the molten steel, adjusting the molten steel winding length, adjusting the molten steel winding strength and adjusting the molten steel winding direction, wherein the central flow velocity is determined by the magnetic field strength generated by the brake roller, the molten steel winding length is determined by the spacing between the first flow control roller and the third flow control roller, the molten steel winding strength is determined by the magnetic field strength generated by the traveling wave roller, and the molten steel winding direction is determined by the working mode of the first flow control roller and the third flow control roller; Step S6, judging whether the adjustment of the flow state of the molten steel is qualified based on the change of the liquid level of the molten steel before and after the adjustment; Step S7, repeating steps S3-S6 to continuously monitor the flow state of molten steel of the casting.

2. The flow control method for a roller type electromagnetic stirring device according to claim 1, characterized in that: In step S2, the product of the second preset length and the preset coefficient is calculated, and the working modes of the first flow control roller and the third flow control roller are determined based on the comparison result of the first preset length and the product, wherein the preset coefficient is 1.

5.

3. The flow control method for a roller type electromagnetic stirring device according to claim 1, characterized in that: In the step S4, it includes: Step S41, judging whether it is necessary to adjust the temperature of the single ingot according to the first characteristic of the surface temperature curve of the single ingot; Step S42, when it is determined that temperature adjustment is required, judging whether to adjust the flow state of the molten steel according to the second characteristic of the surface temperature curve of each ingot; The ingot surface temperature curve is a temperature variation curve generated by detecting a single detection point on the ingot surface according to a time sequence process.

4. The flow control method for a roller type electromagnetic stirring device according to claim 3, characterized in that: In step S41, the determination of whether the temperature of the ingot needs to be adjusted includes: Step S411, dividing the surface temperature curve of the casting into a plurality of temperature curve segments, each temperature curve segment is determined according to the temperature slope value or temperature value at the detection point; Step S412, calculating the first characteristic based on the duration of each temperature curve segment, and determining whether the temperature of the ingot needs to be adjusted based on the first characteristic.

5. The flow control method for a roller type electromagnetic stirring device according to claim 4, characterized in that: In the step S411, each temperature curve segment is divided, including: Determining segment points of the temperature curve segments on the surface temperature curve of the casting billet based on a preset temperature slope interval to determine each temperature curve segment; Determine the temperature curve segment based on the time point corresponding to the current temperature value and the time point determined by the temperature value on the surface temperature curve of the casting billet that meets the preset maximum temperature difference; The temperature curve segment is determined based on the continuous time length of time that each temperature value on the surface temperature curve of the casting billet exceeds a preset temperature value.

6. The flow control method for a roller type electromagnetic stirring device according to claim 5, characterized in that: In step S42, when it is determined that the temperature of the ingot needs to be adjusted, the absolute value of the difference between the temperature at each time temperature monitoring point on the corresponding temperature curve segment and the preset temperature is calculated, and based on the number of monitoring points whose absolute value of the difference is greater than or equal to the preset temperature difference, it is determined whether the flow state of the molten steel needs to be adjusted, wherein: If the number of monitoring points is greater than or equal to the preset number of monitoring points, it is determined that the flow state of the molten steel needs to be adjusted.

7. The flow control method for a roller type electromagnetic stirring device according to claim 6, characterized in that: In step S5, when it is determined that the flow state of the molten steel needs to be adjusted, the adjustment object is determined according to the point distribution of each detection point corresponding to each temperature curve segment, and the adjustment method of the flow state of the molten steel is determined according to the adjustment object and the number of points of each detection point; Wherein, the adjustment object includes the brake roller and the traveling roller.

8. The flow control method for a roller type electromagnetic stirring device according to claim 7, characterized in that: In step S5, when it is determined that the flow state of the molten steel needs to be adjusted, if the total number of detection points corresponding to each temperature curve segment is less than or equal to the preset number of detection points, and the detection points are located at the brake roller position, it is determined that the central flow rate of the molten steel needs to be adjusted; if the detection points are located at the traveling roller position, it is determined that the molten steel winding length or the molten steel winding strength needs to be adjusted; If the number of detection points corresponding to each temperature curve segment is greater than the preset number of points, it is determined to adjust the circling direction of the molten steel.

9. The flow control method for a roller type electromagnetic stirring device according to claim 1 or 8, characterized in that: In the step S5, the adjustment parameters of the flow control rollers include the distance between the first flow control roller and the third flow control roller, the working mode, and the current intensity of the brake roller and the traveling roller.

10. The flow control method for a roller type electromagnetic stirring device according to claim 9, characterized in that: In step S6, judging whether the adjustment of the flow state of the molten steel is qualified includes: Based on the comparison between the height difference of the molten steel surface before and after the adjustment and the preset height difference, it is judged whether the adjustment of the flow state of the molten steel is qualified; Based on the comparison between the fluctuation amplitude of the adjusted molten steel level height and the preset fluctuation amplitude, it is judged whether the adjustment of the molten steel flow state is qualified.

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