A method and system for selecting vibration parameters of a high-pulling speed continuous casting crystallizer

Abstract

This invention relates to a method and system for selecting vibration parameters of a high-speed continuous casting mold, including determining the starting casting speed, the target casting speed range, and selecting the negative slip time t within the target casting speed range. N Range; determined by negative slip time t N The range yielded the frequency-negative slip-time curves (f-t) under different tension speeds and amplitudes. N Curve, passing through the starting acceleration t N and t N The method involves projecting a certain value onto a horizontal plane to obtain the amplitude and frequency range that meet the conditions. A series of processing and operations are then performed to obtain the amplitude and frequency that meet the conditions. Through this invention, the casting speed of slabs, square billets, round billets, and irregularly shaped billets can be increased by 10% to 200%, significantly improving production efficiency and ensuring the good operation of the hydraulic vibration equipment in the crystallizer. Furthermore, the surface and internal quality of the cast billet are comparable to that under conventional casting speed conditions, and the product quality meets customer requirements.

Description

Technical Field

[0001] This invention belongs to the field of continuous casting crystallizer technology, specifically relating to a method and system for selecting vibration parameters of a high-speed continuous casting crystallizer. Background Technology

[0002] In recent years, high efficiency has been the main development direction of continuous casting in China. Its core technology is high casting speed. As a link between steelmaking and rolling, continuous casting has a direct impact on furnace-machine matching, steel product quality and heating furnace energy consumption.

[0003] Increasing the continuous casting speed can reduce carbon emissions, save labor and equipment maintenance costs, and accelerate production while optimizing furnace-mill matching. However, ensuring product quality meets requirements at high casting speeds remains a technical challenge for different steel grades and billet shapes.

[0004] At high casting speeds, the heat exchange in the crystallizer increases per unit time, the initial billet shell thickness becomes thinner, the static pressure of the molten steel increases, the consumption of protective slag decreases, and it becomes difficult to form a uniform slag film. This leads to uneven heat transfer between the billet shell and the crystallizer, poorer lubrication conditions, an increased tendency for the billet shell to stick in the crystallizer, and deterioration of the surface quality of the cast billet.

[0005] For slabs, the large cross-section of the billet easily leads to uneven distribution of the protective slag within the crystallizer, resulting in a large transverse temperature difference in the billet shell. Under the combined action of molten steel cooling and hydrostatic pressure, the protective slag cannot fully fill the shell, leading to unsteady cooling and resulting in a billet shell of uneven thickness. For square billets, due to the two-dimensional heat transfer and strong contraction at the corners, the cooling intensity and uniformity of the face and corners are inconsistent. Poor lubrication of the protective slag can easily lead to adhesion, depressions, or cracks. For round billets, although there is no difference in heat transfer characteristics between the corners and face, due to the coordination of circumferential deformation, if uneven penetration of the protective slag occurs due to flow field, liquid surface fluctuations, or equipment problems, all the circumferential contraction deformation will be concentrated at the defect, making the quality problem more significant. Continuous casting of irregularly shaped billets involves more chamfers, resulting in stronger surface and corner inhomogeneity during solidification. Therefore, high-speed continuous casting of slabs, square billets, round billets, and irregularly shaped billets all place high demands on the crystallizer vibration parameters and the related uniformity and stability of the protective slag. Summary of the Invention

[0006] In order to overcome the above-mentioned problems in the prior art, the present invention provides a method and system for selecting vibration parameters of a high-speed continuous casting crystallizer, which is used to solve the above-mentioned problems in the prior art.

[0007] A method for selecting vibration parameters of a high-speed continuous casting crystallizer includes the following steps:

[0008] S1. Determine the starting speed and target speed range for continuous casting;

[0009] S2. Determine the negative slip time corresponding to the starting speed, and set the negative slip time t at the target speed according to the site requirements. N scope;

[0010] S3. Due to negative slip time t N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N By projecting a certain value onto a horizontal plane, we can obtain the amplitude value and frequency range of the negative slip time required to achieve the target speed from the starting speed.

[0011] S4. Obtain the vibration parameters using the amplitude and corresponding tension speed obtained in S3, and determine whether the vibration parameter values ​​meet the process and equipment requirements. If they do, further determine the vibration frequency based on the determined amplitude; if they do not meet the requirements, appropriately increase the amplitude value.

[0012] S5. At negative slip time t N A time constant is determined within the range, and the corresponding amplitude and frequency values ​​are selected based on this constant.

[0013] S6. Determine whether the slag consumption is within a reasonable range based on the selected vibration frequency. If it is, select this vibration frequency and amplitude. If not, return to S5 and repeat the process.

[0014] S7. Repeat S2-S6 to obtain the amplitude, frequency and negative slip time at different tension speeds, and select the corresponding inflection point determination method according to the changing trend of negative slip time.

[0015] S8. Test whether the working status of the crystallizer vibration table is normal under different pulling speeds and vibration frequencies and amplitudes. If it is operating normally, determine the corresponding amplitude and vibration frequency as vibration parameters.

[0016] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the high-speed continuous casting is a square billet casting speed, a round billet casting speed, a slab casting speed, a rectangular billet casting speed, or a casting speed for other irregularly shaped billets.

[0017] As described above, and in accordance with any possible implementation, a further implementation is provided, wherein the negative slip time t N The range is 0.05 to 0.25 s.

[0018] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the frequency range in S3 includes a high-frequency range and a low-frequency range, a lower frequency value is selected in the high-frequency range, and a higher frequency value is selected in the low-frequency range.

[0019] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the vibration parameter Z is calculated using the following formula: Z = 2S / Vc, where S is the amplitude and Vc is the tension speed corresponding to the amplitude.

[0020] In addition to the aspects described above and any possible implementation, an implementation is further provided in which the negative slip ratio NS in the low-frequency range is 2.4% < NS ≤ 20%, and the negative slip ratio NS in the high-frequency range is 2.4% > NS ≥ -240%.

[0021] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the reasonable range of slag consumption is 0.1 to 0.5 kg / t.

[0022] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the billet drawing speed is greater than or equal to 3.5 m / min, the round billet drawing speed is greater than or equal to 3.0 m / min, the slab drawing speed is greater than or equal to 1.5 m / min, the rectangular billet drawing speed is greater than or equal to 2.0 m / min, or the drawing speed of other irregular billets is greater than or equal to 1.2 m / min.

[0023] As described above and in any possible implementation, a further implementation is provided, wherein the method for determining the inflection point is specifically based on the change of tN during the increase of the tension speed, and t is selected accordingly. N The amplitude or slag consumption is used as the turning point. Positive control is used at the turning point, and reverse control is used after the turning point.

[0024] The present invention also provides a vibration parameter selection system for a high-speed continuous casting crystallizer, the system being used to implement the selection method described above, the system comprising:

[0025] The first determining module is used to determine the starting casting speed and the target casting speed range for continuous casting.

[0026] The second determining module is used to determine the negative slip time corresponding to the starting speed, and to set the negative slip time t at the target speed according to the site requirements. N scope;

[0027] The third determining module is used to determine the negative slip time t. N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N By projecting a certain value onto a horizontal plane, we can obtain the amplitude value and frequency range of the negative slip time required to achieve the target speed from the starting speed.

[0028] The first judgment module is used to obtain vibration parameters based on the obtained amplitude and corresponding tension speed, and to determine whether the vibration parameter values ​​meet the process and equipment requirements. If they meet the requirements, the vibration frequency is further determined based on the determined amplitude; if they do not meet the requirements, the amplitude value is appropriately increased.

[0029] The first selection module is used to select the negative slip time t. N A time constant is determined within the range, and the corresponding amplitude and frequency values ​​are selected based on this constant.

[0030] The second judgment module is used to determine whether the slag consumption is within a reasonable range based on the selected vibration frequency. If it is, the vibration frequency and amplitude are selected; otherwise, the process is repeated.

[0031] The fourth determination module is used to select the corresponding inflection point determination method based on the changing trend of the negative slip time, based on the amplitude, frequency and negative slip time values ​​obtained at different tension speeds.

[0032] The fourth determination module is used to test whether the working status of the crystallizer vibration table is normal under different pulling speeds and vibration frequencies and amplitudes. If it is operating normally, the corresponding amplitude and vibration frequency are determined as vibration parameters.

[0033] Beneficial effects of the present invention

[0034] The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to the present invention includes determining the starting casting speed, the target casting speed range, and selecting the negative slip time t within the target casting speed range. N Range; determined by negative slip time t N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N The method involves projecting a certain value onto a horizontal plane to obtain the amplitude and frequency range that meet the conditions. A series of processing and operations are then performed to obtain the amplitude and frequency that meet the conditions. Through this invention, the casting speed of slabs, square billets, round billets, and irregularly shaped billets can be increased by 10% to 200%, significantly improving production efficiency and ensuring the good operation of the hydraulic vibration equipment in the crystallizer. Furthermore, the surface and internal quality of the cast billets are comparable to that under conventional casting speeds, and the product quality meets customer requirements. In existing technologies, the casting speed for slab series steel grades is 1.0 to 1.5 m / min. After adopting this invention, the maximum casting speed for slabs is 1.8 to 3.0 m / min. For small square billet and small round billet series steel grades, the original casting speed was 2.0-2.5 m / min, which is increased to 3.0-6.5 m / min after the speed increase. The comparison shows that the increased casting speed significantly increases the steel throughput per unit time, accelerates the production pace, and increases capacity by 10% to 200% within the same cycle. Attached Figure Description

[0035] Figure 1 Schematic diagram showing the relationship between negative slip time and vibration frequency and amplitude at different tension speeds (a) 1.2 m / min, (b) 1.5 m / min, and (c) 2.0 m / min;

[0036] Figure 2 Different V C Under S, f and t N t P A diagram illustrating the relationship, where (a)V C =1.2m / min, S=2.5mm; (b)V C =1.5m / min, S=3.5mm;

[0037] Figure 3 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0038] To better understand the technical solution of this invention, the content of this invention includes, but is not limited to, the specific embodiments described below. Similar technologies and methods should be considered within the scope of protection of this invention. To make the technical problem to be solved, the technical solution, and the advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0039] It should be understood that the embodiments described in this invention are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0040] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] like Figure 3 As shown, this invention provides a method for selecting vibration parameters of a high-speed continuous casting crystallizer, comprising the following steps:

[0042] Step 1: Determine the casting speed range; for example, the starting casting speed is VC0, and the target casting speed is VC1. The target casting speed VC1 is determined by combining the on-site production conditions such as the metallurgical length of the casting machine, the crystallizer, the maximum cooling intensity of the secondary cooling water, and the cross-sectional specifications of the billet. The solidification process is simulated using FLUENT to determine whether the solidification endpoint of the billet at each casting speed is less than the fire-cutting position. The higher the casting speed, the further the solidification endpoint moves. When the casting speed reaches a certain value, the solidification endpoint is 3m away from the fire-cutting position, which is the target casting speed VC1.

[0043] Step two involves determining the negative slip time corresponding to the initial casting speed VC0, and initially setting the negative slip time range at the target casting speed VC1 based on site requirements. This allows for the determination of the negative slip time range at various casting speeds between the initial and target speeds, enabling the use of the maximum and minimum negative slip time values ​​for horizontal projection and amplitude selection constraints. Furthermore, the negative slip time is also affected by the crack sensitivity of the cast steel grade, and must be determined in conjunction with actual production conditions during on-site production.

[0044] Step 3, based on the negative slip time t N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N By projecting a certain value onto a horizontal plane, we can obtain the amplitude value and frequency range that satisfy the negative slip time required from the starting speed to the target speed. We can initially obtain the combination of amplitude and frequency range that satisfies the negative slip time. Subsequently, we can filter the combination data of these amplitude and frequency ranges by restricting the magnitude of the vibration parameter values.

[0045] Step four, using the amplitude and corresponding pulling speed obtained in step three, and the t corresponding to the starting pulling speed. N and t N By projecting a certain value onto a horizontal plane, the amplitude values ​​required for the negative slip time at various tension speeds can be obtained. These amplitudes and tension speeds have a one-to-one or many-to-one matching relationship. Then, the vibration parameter Z is calculated using the vibration parameter formula Z = 2S / Vc, where S and Vc are the amplitude and the corresponding tension speed, respectively. It is then determined whether the vibration parameter value meets the process and equipment requirements. If it does, the vibration frequency is further determined based on the determined amplitude; if not, the amplitude value is appropriately increased. After increasing the amplitude value, the Z value is re-evaluated to see if it meets the process and equipment conditions. The effect of this step is that the Z value is determined by the amplitude and tension speed, and the Z value affects the significance of the negative slip time changing with the vibration frequency. Therefore, this step controls the Z value within a limited range.

[0046] Step 5: Within the negative slip time range of Step 2, determine a fixed value for the negative slip time. From this fixed value, the corresponding amplitude and frequency values ​​(referred to as frequency values) can be obtained. When selecting a specific frequency value, such as... Figure 2 As shown, a lower frequency value is selected in the high-frequency region to increase the positive slip time, thereby increasing the consumption of protective slag and improving lubrication; a higher frequency is selected in the low-frequency region to avoid t N The region of sudden change with f ( Figure 2 (Instability region) and critical frequency f0 (when f = f0, t) N=0), in order to improve the stability of process parameters, this step is to further screen the initially obtained amplitude value and the corresponding frequency range, and further determine the precise frequency value by combining the high and low frequency range with the high-speed production requirements on site. In subsequent operations, this frequency value is selected at this speed.

[0047] Step six: Determine if the slag consumption is within a reasonable range. If the mold flux consumption is 0.1-0.5 kg / t when using the amplitude and frequency values ​​selected in step five, then the rationality of the parameters in step five is further confirmed. This involves on-site verification of the parameters in step five to ensure sufficient flux to form a uniform slag film for lubrication between the billet shell and the mold. If the slag consumption is within a reasonable range, select this frequency and amplitude. If not, select a new frequency value within the frequency range according to step five. Step four verified the rationality of the Z-value formed by the amplitude and casting speed. The purpose of this step is to further verify the selected frequency value within the specified frequency range.

[0048] Step 7: Repeat the above steps to obtain the amplitude S and frequency f values ​​at different pulling speeds, and calculate the negative slip time obtained from the frequency and amplitude at different pulling speeds. Steps 1 and 2 determine the maximum and minimum values ​​of the negative slip time, forming an interval, i.e., the negative slip time range. However, the negative slip time at each pulling speed is a constant within this interval and needs to be calculated by combining all pulling speeds within the range and the amplitude and frequency values ​​from Step 6. For example: in Steps 1 and 2, t... N The time is 0.1-0.15s. Combining this with the parameters from step six, we can obtain: when the pulling speed is 1.0 m / min, t... N =0.12s, at a pulling speed of 1.1m / min, t N =0.115s. Monitor the trend of the pulling speed and select the corresponding inflection point judgment method. Design an f-VC control model that combines positive and negative vibration modes throughout the entire pulling speed range. Based on the previous steps, the amplitude and frequency values ​​at each pulling speed and the precise negative slip time values ​​corresponding to each pulling speed are obtained. Then, observe the trend of the negative slip time when using the amplitude and frequency in step six as the pulling speed increases. Based on this trend, determine the inflection point determination method for the positive and negative vibration modes and determine the pulling speed corresponding to the inflection point.

[0049] Step eight involves testing the vibration frequency and amplitude at different casting speeds. Monitoring the operation of the crystallizer vibration table using these parameters ensures normal operation. If the equipment operates stably, these parameters are confirmed as the optimal vibration parameters for the casting machine. After selecting the parameters and determining the forward and reverse vibration modes, this step provides a final verification of the adaptability of the equipment on-site, ensuring that the casting machine can adapt to and achieve its best working condition under normal operating conditions.

[0050] Preferably, the high-speed continuous casting is characterized by a billet casting speed of not less than 3.5 m / min for square billets, not less than 3.0 m / min for round billets, not less than 1.5 m / min for slabs, not less than 2.0 m / min for rectangular billets, or not less than 1.2 m / min for irregularly shaped billets.

[0051] Preferably, the reasonable negative slip time t N The range is 0.05–0.25 s. When the negative slip time is less than 0.05 s, such as… Figure 2 As shown, the frequency of vibration has a very poor effect on the negative slip time. During production, if there is a slight change in the frequency of the crystallizer, the negative slip time may be equal to 0, and the crystallizer and the billet shell will not produce negative slip movement, which will affect the demolding effect of the billet. When the negative slip time is greater than 0.25s, it can be seen from the formula (2) below that the positive slip time will decrease. It can be seen from the formula (5) that the positive slip time is proportional to the amount of protective slag. At this time, if the amount of protective slag is too small, it will lead to poor lubrication of the crystallizer and production problems such as the billet shell sticking to the crystallizer.

[0052] Preferably, the vibration mode is sinusoidal vibration or non-sinusoidal vibration. The method of the present invention meets the selection requirements of amplitude and frequency for sinusoidal vibration or non-sinusoidal vibration during the parameter selection process.

[0053] Preferably, considering the stability of the crystallizer vibration equipment, the low-frequency region satisfies 1≤Z<5, and the high-frequency region satisfies 1≤Z<7.

[0054] Preferably, when selecting the vibration frequency, the low-frequency range should be selected within a range of relatively high vibration frequencies of 2.4% < NS ≤ 20%, and the high-frequency range should be selected within a range of relatively low vibration frequencies of 2.4% > NS ≥ -240%, while ensuring stable operation of the equipment. For example... Figure 2 As shown, when NS = 2.4%, the frequency-negative slip time curve is divided into two parts. In the low-frequency region, a frequency of 2.4% < NS ≤ 20% is used to ensure that it does not approach the critical frequency (i.e., at the critical frequency, the negative slip time is 0, and no negative slip motion occurs). The frequency-negative slip time curve varies too much, so NS = 20% and above cannot be used as the modeling region for the vibration model. In the high-frequency region, a frequency of 2.4% > NS ≥ -240% is used to prevent the frequency from exceeding the maximum vibration frequency of the crystallizer, which would cause the vibration table to malfunction.

[0055] Preferably, the reasonable range of protective slag consumption is 0.1 to 0.5 kg / t. If the slag consumption is less than 0.1 kg / t, it will cause poor lubrication and heat transfer between the crystallizer and the primary billet shell. If the slag consumption is greater than 0.5 kg / t, it will result in excessive slag film thickness, which will reduce the heat transfer between the crystallizer and the billet shell, making the billet shell thickness thinner when it exits the crystallizer, which may easily lead to a tower crane accident.

[0056] Preferably, the methods for determining the inflection point fall into three categories: ① Based on the selected amplitude and frequency values ​​at each tension speed, the corresponding t can be calculated. N If t N The overall trend of change decreases as the pulling speed increases, then t N It equals a certain value (such as t) N The turning point is the pulling speed at 0.1s. Before the turning point, the pulling speed uses a forward f-Vc control model; after the turning point, the pulling speed uses a reverse control model. ② If, during the increase in pulling speed, t... N The value remains basically unchanged (t at different pulling speeds) N If the difference in value is ≤0.015s, then the condition is met when the pulling speed increases while the amplitude increases. The pulling speed at a certain amplitude value (e.g., 3.5mm) is taken as the turning point. The pulling speed range with an amplitude less than this value uses positive control, and the pulling speed range with an amplitude greater than this value uses reverse control. ③ If, during the pulling speed increase, t N The frequency of vibration increases with increasing casting speed, while the flux (tP) decreases. Taking a certain value (e.g., 0.1 kg / t) as the turning point, the first half uses a forward f-Vc control model, and the second half uses a reverse f-Vc control model to ensure the flux consumption remains between 0.1 and 0.5 kg / t. In the combined forward and reverse f-Vc control model, before the turning point, the vibration frequency increases with increasing casting speed, while the amplitude remains basically constant or increases slightly with casting speed. At this point, a smaller amplitude can reduce the depth of vibration marks and prevent transverse cracks on the billet surface. After the turning point, the vibration frequency decreases with increasing casting speed, while the amplitude increases. At this point, low-frequency, large-amplitude vibrations can improve the billet demolding effect, increase flux consumption, and prevent adhesion.

[0057] Specifically, the method for selecting sinusoidal vibration parameters of a high-speed continuous casting crystallizer according to the present invention simultaneously achieves multiple objectives such as billet demolding, uniform distribution of protective slag, and qualified billet surface quality, and specifically includes the following steps:

[0058] Step 1: Determine the pulling speed range; for example, starting pulling speed VC0, target pulling speed VC1;

[0059] Step 2: Determine the negative slip time corresponding to the starting speed, and initially set the negative slip time range at the target speed based on site requirements; each parameter is calculated using the following formulas:

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066] Among them, t N is the negative slippage time, t P is the positive slippage time, with the unit of s; Z is the vibration parameter, which has no actual metallurgical significance; d is the depth of the mold oscillation mark, in mm; Q is the consumption of mold powder, in kg / t; η is the viscosity of the mold powder, in g / (cm·s); K1 and K2 are empirical values, with the value range between 0 and 1, and are determined according to the on-site production conditions. Vm is the average speed of the mold oscillation, in m / min. NS is the negative slip rate.

[0067] Step three, according to the t N calculation formula (1), obtain the f-t C curves under different drawing speeds V N and different amplitudes S, as Figure 1 shown. From the range of the negative slippage time t N (composed of the maximum and minimum values of t N ), obtain the f-t N curves of the oscillation frequency negative slippage time under different drawing speeds and amplitudes, that is, the f-t N curves. Make a horizontal plane projection through the t N at the starting drawing speed and t

[0068] equal to a certain value, and obtain the amplitude value and the oscillation frequency range that meet the negative slippage time required from the starting drawing speed to the target drawing speed; C Step four, calculate the Z value from the amplitude S and the drawing speed V

[0069] that meet the conditions, and judge whether the Z value meets the standard. This invention not only selects the oscillation frequency in the high-frequency region, but also selects the oscillation frequency value in the low-frequency region. For the high-frequency region, the Z value ensures 1 < Z < 7 and the negative slip rate satisfies 2.4% > NS ≥ -240%, and for the low-frequency region, the value ensures that the negative slip rate 2.4% < NS ≤ 20%, and 1 < Z < 5. If it is satisfied, further determine the oscillation frequency value on the basis of determining the amplitude; if it is not satisfied, then appropriately increase the amplitude S value; N Step five, after the amplitude S value is determined, the horizontal plane projection of the established t N range and the f-t Figure 2 curve generate several intersection points, obtain the oscillation frequency range under different S values, and then select the oscillation frequency value within this range. When selecting the specific amplitude and oscillation frequency values, as N shown, select a lower oscillation frequency value in the high-frequency region to increase the positive slippage time, thereby increasing the consumption of mold powder and improving lubrication; select a higher oscillation frequency in the low-frequency region to avoid the sudden change area of t Figure 2 = 0). N

[0070] ​Step six: Determine if the protective slag consumption is within a reasonable range. Considering the reduced slag consumption at high casting speeds, select 0.1-0.5 kg / t as the protective slag consumption to ensure sufficient protective slag between the billet shell and the crystallizer to form a uniform slag film. If the slag consumption is within the range, select this frequency and amplitude; otherwise, follow step four and appropriately increase the amplitude S value within a reasonable Z value range.

[0071] Step 7: Calculate the amplitude S and frequency f at different pulling speeds using the above method, and obtain the positive and negative fV values ​​within the pulling speed range. C In the control model, specifically, the methods for selecting inflection points are divided into three categories: ① If t N It decreases as the pulling speed increases, then it is expressed in t. N = The pulling speed at a certain value (e.g., 0.1s) is the turning point. The pulling speed before and after the turning point uses a positive f-Vc control model, while the pulling speed after the turning point uses a negative control model. ② If, during the increase in pulling speed, t N The value remains basically unchanged (t at different pulling speeds) N If the difference in values ​​is ≤0.015s, then this condition is met when the pulling speed increases while the amplitude increases. The pulling speed at a certain amplitude value (e.g., 3.5mm) is taken as the turning point. The pulling speed range when the amplitude is less than this value and the pulling speed at this turning point are represented by the positive fV. C The control model uses a reverse fV method for the pulling speed range when the amplitude exceeds this fixed value. C Control model. ③ If during the increase in pulling speed, t N It shows an increasing trend, at which point t P The consumption of protective slag is reduced to a certain value (e.g., 0.1 kg / t) as the turning point. A positive f-Vc control model is used in the first half and at the turning point, while a negative f-Vc control model is used in the second half to ensure that the consumption of protective slag is maintained at 0.1 to 0.5 kg / t.

[0072] Step 8: Before the inflection point, the vibration frequency increases with increasing casting speed, while the amplitude remains basically unchanged or increases slightly with increasing casting speed. A smaller amplitude and a larger vibration frequency can reduce the depth of vibration marks and prevent transverse cracks from forming on the surface of the billet. After the inflection point, the vibration frequency decreases with increasing casting speed, while the amplitude increases with increasing casting speed. At this point, the vibration frequency f relative to t... N The effects of low frequency and large amplitude vibration on the casting depth are relatively small, therefore, low frequency and large amplitude vibration are used to improve the casting demolding effect and increase the amount of protective slag consumed. Specifically, fV C The control model is as follows:

[0073] Positive:

[0074] Reverse:

[0075] Where a, b, e, c, d, m, n each represent a variable coefficient, a > 0, e > 0, c < 0, d > 0, m > 0. The values ​​of these variable coefficients are calculated from the amplitude and frequency at each tension speed obtained in the above 8 steps. Example of calculation process: In the first 8 steps, all the amplitudes and frequencies corresponding to the range from the starting speed to the target speed have been obtained. For example, when the starting speed is 1.4 m / min, the amplitude is 3.2 mm and the frequency is 108. When the speed is 1.5 m / min, the amplitude is 3.2 mm and the frequency is 113. When the speed is 1.6 m / min, the amplitude is 3.2 mm and the frequency is 120. Then, using formula (7): f = a × speed + b, substituting the frequency when the speed is 1.4-1.6 m / min, we can get a set of equations: 108 = a × 1.4 + b, 120 = a × 1.6 + b. Solving the two equations, we can get a = 57 and b = 28. At this time, S = e = 3.2 mm. In addition, t is calculated according to formula (1). N and compare t N The trend of t with changing pulling speed was found to be as follows: when the pulling speed is 1.4-1.6 m / min, N Since the difference is less than 0.015s, the second inflection point discrimination method is selected. The inflection point is chosen when the amplitude is a certain value (e.g., 3.5mm). At this time, the pulling speed is 1.7m / min, so the inflection point is taken as the pulling speed of 1.7m / min. Then, when the pulling speed is ≥1.7m / min, the reverse vibration mode is adopted. At 1.7m / min, the parameters obtained from the first 6 steps are: at 1.7m / min, the vibration frequency is 132 and the amplitude is 4.1mm; at 1.8m / min, the vibration frequency is 127 and the amplitude is 4.3mm; at 1.9m / min, the vibration frequency is 121 and the amplitude is 4.4mm. Similarly, substituting into formula (8), we get: 132=c×1.7+d, 121=c×1.9+d, solving for c=-53, d=222. 4.1=m×1.7+n, 4.4=m×1.9+n, solving for m=1.7, n=1.2. The vibration frequency and amplitude under different casting speeds are tested, and it is observed whether the working state of the crystallizer vibration table is normal when using this parameter. If the equipment runs stably, it is determined to be the vibration parameter of this casting machine.

[0076] Example 1

[0077] This invention provides a method for selecting crystallizer vibration parameters during high-speed continuous casting of ultra-wide slabs. In this embodiment, the steel grade used is AH36 steel (C: 0.15-0.18), with a cross-section of 150mm × 2560mm. The crystallizer vibration mode is sinusoidal vibration, and the crystallizer vibration equipment of the high-speed casting machine can achieve a vibration range of 0–240 min. -1 The frequency and amplitude of the vibration are 0-6 mm.

[0078] Before the speed increase, the casting machine speed was 1.5 m / min. Using FLUENT numerical simulation, the solidification process and the liquid level fluctuation in the crystallizer were calculated to determine whether the solidification endpoint and the metallurgical length of the casting machine, the liquid level in the crystallizer, etc. were within a controllable range under different casting speeds. The casting machine parameters were investigated, and it was finally determined that the casting speed of No. 1 casting machine could be increased to a maximum of 1.8 m / min.

[0079] At the original drawing speed of 1.5 m / min, the negative slip time is 0.13 s. Considering that transverse cracks caused by surface vibration marks are easily generated in the width direction of ultra-wide slabs at high drawing speeds, and that the depth of vibration marks is positively correlated with the negative slip time, the negative slip time at a drawing speed of 1.8 m / min is selected to be 0.11 to 0.12 s.

[0080] exist Figure 2 In the middle, along t N =0.13s,t N =0.1s, project onto the horizontal plane, and intersect with ft under different amplitudes S respectively. N The curve intersects at four points, and the available amplitude and frequency parameters are shown in Table 1:

[0081] Table 1 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and the frequency f take values ​​in the range

[0082]

[0083] Calculating the Z-value reveals that it satisfies the conditions for high and low frequency values. Therefore, the amplitude and frequency in Table 1 are usable. Further determination of the negative slip time t is then possible. N As a constant, the amplitude and frequency values ​​are shown in Table 2:

[0084] Table 2 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and frequency f values ​​under different modes

[0085]

[0086] From equation (2), it can be seen that when the pulling speed is 1.5 m / min and the frequency is 123 Hz, the positive slip time is 0.357 s. The viscosity of the protective slag used in this embodiment is 0.5 Pa·s, and K is taken as an empirical value of 0.7. Therefore, from equation (5), it can be seen that the protective slag consumption is 0.24 kg / t when the pulling speed is 1.5 m / min and about 0.2 kg / t when the pulling speed is 1.8 m / min, which meets the requirements (0.1 kg / t ≤ Q < 0.5 kg / t), that is, the parameters are usable.

[0087] Based on the above method, the amplitude and frequency at tension speeds of 1.5-1.8 m / min were calculated similarly, and the data are shown in the table below:

[0088] Table 3. Amplitude S and frequency f at different pulling speeds

[0089]

[0090] By performing a linear fit on the data in the table, i.e., setting up a system of two linear equations for the vibration frequency and the tension speed respectively, and substituting the data from the table above, we can obtain the following system of equations:

[0091]

[0092] Solving these equations, we get a = 113, b = -47, e = 3.2 or 2.9, c = -53, d = 173, m = 3.6, and n = -2.3. This gives us the forward and reverse velocity fV under different pulling speeds. C The control model is as follows:

[0093] Positive: Reverse:

[0094] During the increase of tension speed, the negative slip time remains basically unchanged (t N For changes less than 0.015s, the second method for determining the inflection point is adopted, with amplitude S = 3.5mm as the selected value. When the amplitude S is 3.5mm, the drawing speed is equal to 1.6m / min. Therefore, when the drawing speed is 0-1.6m / min, the positive mode is adopted, that is, the frequency increases with the increase of the drawing speed, and the amplitude is set to 3.2 or 2.9mm. For the drawing speed of 1.7-1.8m / min, the reverse mode is adopted, that is, the frequency decreases and the amplitude increases with the increase of the drawing speed. This makes the change of negative sliding time smaller with the increase of drawing speed, while the positive sliding time increases continuously, increasing the slag consumption and ensuring the lubrication conditions of the ultra-wide slab surface.

[0095] Since the fan-shaped section of the No. 1 casting machine is 16m apart and the slab thickness is 150mm, cracks are prone to occur in the fan-shaped section, which limits the further increase of the casting speed. Therefore, the maximum casting speed is only increased to 1.8m / min, and the vibration equipment works stably at this casting speed.

[0096] Example 2

[0097] This invention provides a method for selecting crystallizer vibration parameters during high-speed continuous casting of ordinary slabs. In this embodiment, the steel grade used is AH36 steel (C: 0.15-0.18), with a cross-section of 200mm × 1650mm. The crystallizer vibration waveform is sinusoidal, and the crystallizer vibration equipment can achieve a vibration frequency of 0–270 min. -1 The frequency and amplitude of the vibration are 0-6 mm.

[0098] Before the speed increase, the casting machine's pulling speed was 1.4 m / min. Numerical simulation was used to calculate the solidification process and various production indicators to determine the solidification endpoint and the metallurgical length of the casting machine after the speed increase. The performance of the casting machine was also evaluated, and it was finally determined that the pulling speed of the No. 2 casting machine could be increased to a maximum of 2.0 m / min.

[0099] At the original drawing speed of 1.4 m / min, the negative slip time is 0.14 s. Considering the influence of the vibration mark depth of ultra-wide slabs at high drawing speeds, and the negative slip time t N The larger the value, the greater the depth of the oscillation mark on the billet. Therefore, the negative slip time is initially selected as 0.12 to 0.13 s at a casting speed of 2.0 m / min.

[0100] exist Figure 1 In (c), along t N Calculate the horizontal planes at 0.1 and 0.14s, and intersect them with ft under different amplitudes S. N The curve intersects at several points, at which point the pulling speeds are respectively

[0101] At 1.4 m / min and 2.0 m / min, the negative slip time is found to satisfy 0.1 s ≤ t ≤ 0.14 s. That is, the available amplitude value is obtained by making a horizontal plane projection, the template is calculated according to formula (1) to obtain the vibration frequency value that meets the conditions, and then the amplitude and pulling speed values ​​are substituted into formula (3) to obtain the Z1 and Z2 values.

[0102] Table 4 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and the frequency f take values ​​in the range

[0103]

[0104] The Z-value was calculated and found to meet the requirements for selecting high and low frequencies. Therefore, the amplitude and frequency in Table 4 are usable. Further, the negative slip time at a pulling speed of 2.0 m / min was determined to be a constant of 0.13 s. The amplitude and frequency values ​​obtained from the template calculated by equation (1) are shown in Table 5.

[0105] Table 5 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and frequency f values ​​under different modes

[0106]

[0107] From equation (2), it can be seen that when the pulling speed is 1.4 m / min and the frequency is 87 Hz, the positive slip time is 0.55 s. In this embodiment, the viscosity of the protective slag is expected to be 0.5 Pa·s, and K is taken as an empirical value of 0.7. Therefore, from equation (5), it can be seen that the protective slag consumption is about 0.39 kg / t when the pulling speed is 1.4 m / min and about 0.28 kg / t when the pulling speed is 2.0 m / min, which meets the requirements (0.1 kg / t ≤ Q < 0.5 kg / t), that is, the parameters are usable.

[0108] Based on the above method, the amplitude and frequency at tension speeds of 1.4-2.0 m / min were calculated similarly, and the data are shown in Table 6:

[0109] Table 6. Amplitude S and frequency f at different pulling speeds

[0110]

[0111] By performing a linear fit on the data in the table, i.e., setting up a two-variable linear equation for the vibration frequency and the tension speed respectively, and substituting the data from the table above, we can obtain:

[0112]

[0113] Solving these equations, we get a = 31.6, b = 43, e = 3.2 or 4, c = -26.6, d = 137, m = 2.5, and n = -0.5. This gives us the forward and reverse velocity fV under different pulling speeds. C The control model is as follows:

[0114] Positive: Reverse:

[0115] The fan-shaped section of the No. 2 casting machine is 23m long, which effectively avoids cracks during the straightening process. As the casting speed increases, the negative slip time remains essentially unchanged (t). N For changes less than 0.015s, the second method for determining the inflection point is adopted, with amplitude S = 4.2mm as the selected value. When the amplitude S is 4.2mm, the drawing speed is equal to 1.6m / min. Therefore, the forward mode is adopted when the drawing speed is 0-1.6m / min to reduce the adhesion of the billet shell. The reverse mode is adopted when the drawing speed is 1.7~2.0m / min, which can make the negative sliding time change more stable at higher drawing speeds, while the positive sliding time continuously increases, ensuring slag consumption and good equipment operation during the production process.

[0116] Example 3

[0117] This invention provides a method for selecting crystallizer vibration parameters during high-speed continuous casting of square billets. In this embodiment, the steel grade used is 45# steel (C: 0.27-0.34), with a cross-section of 180mm × 180mm. The crystallizer vibration waveform is sinusoidal, and the crystallizer vibration equipment can achieve a vibration time of 0–350 min. -1 The frequency and amplitude of the vibration are 0-6 mm.

[0118] Before the speed increase, the casting machine's drawing speed was 2.2 m / min. Numerical simulation was used to calculate the solidification process and various production indicators to determine the solidification endpoint and the metallurgical length of the casting machine after the speed increase. The performance of the casting machine was also evaluated, and it was finally determined that the maximum drawing speed of the No. 3 casting machine could be increased to 3.5 m / min.

[0119] At the original pulling speed of 2.2 m / min, the negative slip time is 0.1 s. Considering the reduced consumption of protective slag and the influence of vibration mark depth at high pulling speeds, the negative slip time at a pulling speed of 3.5 m / min is initially selected to be 0.11 to 0.12 s.

[0120] Along t N Calculate the horizontal planes at 0.1 and 0.12s, and intersect them with ft at different amplitudes S. N The curve intersects at several points. At these points, with pulling speeds of 2.2 m / min and 3.5 m / min respectively, the negative slip time satisfies 0.1 s ≤ t ≤ 0.12 s. That is, the usable amplitude value is obtained by projecting onto the horizontal plane. The template is calculated using equation (1) to obtain the vibration frequency value that meets the conditions. Then, according to equation (3), the amplitude and pulling speed values ​​are substituted to obtain the Z1 and Z2 values. The usable amplitude and vibration frequency parameters are shown in Table 7:

[0121] Table 7 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and the frequency f take values ​​in the range

[0122]

[0123] Calculate the Z-value and verify that it meets the requirements. Then, the amplitude and frequency in Table 7 are usable. Further determine that the negative slip time at a tension speed of 3.5 m / min is 0.11 s. The amplitude and frequency values ​​are shown in Table 8.

[0124] Table 8 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and frequency f values ​​under different modes

[0125]

[0126] As shown in equation (2), when the pulling speed is 2.2 m / min and the frequency is 87 Hz, the positive slip time is 0.59 s. The viscosity of the protective slag used in this embodiment is expected to be 0.5 Pa·s, and K is taken as an empirical value of 0.7. Therefore, according to equation (5), the protective slag consumption is about 0.268 kg / t when the pulling speed is 1.4 m / min and about 0.17 kg / t when the pulling speed is 3.5 m / min, which meets the requirements (0.1 kg / t ≤ Q < 0.5 kg / t), that is, the parameters are usable.

[0127] Based on the above method, the amplitude and frequency at tension speeds of 2.2-3.5 m / min were calculated similarly, and the data are shown in Table 9:

[0128] Table 9. Amplitude S and frequency f values ​​at different tension speeds

[0129]

[0130] By performing a linear fit on the data in the table, i.e., setting up a two-variable linear equation for the vibration frequency and the tension speed respectively, and substituting the data from the table above, we can obtain:

[0131]

[0132] Solving these equations, we get a = 37, b = 5.8, e = 4.5 or 5.8, c = -4.6, d = 138, m = 2.5, and n = 1.9. This gives us the forward and reverse velocity fV under different pulling speeds. C The control model is as follows:

[0133] Positive: Reverse:

[0134] The casting machine's sector section is 18m long, effectively preventing cracks during straightening. The negative slip time increases slightly with increasing casting speed. A third inflection point determination method is used, with slag consumption Q = 0.2kg / t as the selected value. Furthermore, Q = 0.2kg / t at a casting speed of 2.7m / min. Therefore, a forward mode is used for casting speeds between 0-2.7m / min, and a reverse mode is used for casting speeds between 2.8 and 3.5m / min. This ensures a longer positive slip time at higher casting speeds, guaranteeing slag consumption and ensuring smooth equipment operation during production.

[0135] Example 4

[0136] This invention provides a method for selecting crystallizer vibration parameters during high-speed continuous casting of round billets. In this embodiment, the steel grade used is 40CrMnMo (C: 0.37~0.45), with a cross-section of φ150mm. The crystallizer vibration waveform is sinusoidal, and the crystallizer vibration equipment can achieve a vibration frequency of 0~260min. -1 The frequency and amplitude of the vibration are 0-7 mm.

[0137] Before the speed increase, the casting machine's pulling speed was 2.4 m / min. Numerical simulation was used to calculate the solidification process and various production indicators to determine the solidification endpoint and the metallurgical length of the casting machine after the speed increase. The performance of the casting machine was also evaluated, and it was finally determined that the pulling speed of the No. 4 casting machine could be increased to a maximum of 3.5 m / min.

[0138] At the original pulling speed of 2.4 m / min, the negative slip time is 0.1 s. Considering the reduced consumption of protective slag and the influence of vibration mark depth at high pulling speeds, the negative slip time at a pulling speed of 3.5 m / min is initially selected to be 0.11 to 0.12 s.

[0139] Along t N Calculate the horizontal planes at 0.1 and 0.12s, and intersect them with ft at different amplitudes S. N At several points on the curve, at pulling speeds of 2.4 m / min and 3.5 m / min respectively, the negative slip time satisfies 0.1 s ≤ t ≤ 0.12 s. The usable amplitude value is obtained by projecting onto a horizontal plane. The frequency value satisfying the condition is calculated using equation (1). Then, the values ​​of Z1 and Z2 are obtained by substituting the amplitude and pulling speed values ​​into equation (3). The usable amplitude and frequency parameters are shown in Table 10.

[0140] Table 10 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and the frequency f take values ​​in the range

[0141]

[0142] Calculate the Z-value and verify that it meets the requirements. Then, the amplitude and frequency in Table 10 are usable. Further determine that the negative slip time at a tension speed of 3.5 m / min is 0.11 s. The amplitude and frequency values ​​are shown in Table 11.

[0143] Table 11 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and frequency f values ​​under different modes

[0144]

[0145]

[0146] As shown in equation (2), when the pulling speed is 2.4 m / min and the frequency is 108 Hz, the positive slip time is 0.45 s. The viscosity of the protective slag used in this embodiment is expected to be 0.5 Pa·s, and K is taken as an empirical value of 0.7. Therefore, according to equation (5), the protective slag consumption is about 0.19 kg / t when the pulling speed is 2.4 m / min and about 0.13 kg / t when the pulling speed is 3.5 m / min, which meets the requirements (0.1 kg / t ≤ Q < 0.5 kg / t), that is, the parameters are usable.

[0147] Based on the above method, the amplitude and frequency at tension speeds of 2.4-3.5 m / min were calculated similarly, and the data are shown in Table 12:

[0148] Table 12 Amplitude S and frequency f at different tension speeds

[0149]

[0150] By performing a linear fit on the data in the table, i.e., setting up a two-variable linear equation for the vibration frequency and the tension speed respectively, and substituting the data from the table above, we can obtain:

[0151]

[0152] Solving these equations, we get a = 11, b = 81, e = 4.2 or 5.8, c = -15.5, d = 166, m = 2, and n = -1. This gives us the forward and reverse velocity fV under different pulling speeds. C The control model is as follows:

[0153] Positive: Reverse

[0154] Due to the 19m length limitation of the casting machine's fan-shaped section, crack formation in the cast billet can only be effectively avoided at casting speeds below 3.5m / min. As the casting speed increases, the negative slip time remains essentially constant (t). N (If the change range is less than 0.015s), the second inflection point determination method is adopted. The amplitude S = 4.2mm is selected as the value, and the casting speed is 2.6m / min when the amplitude S is 4.2mm. Therefore, the forward mode is adopted for casting speed of 0-2.6m / min, and the reverse mode is adopted for casting speed of 2.7~3.5m / min. The equipment operates well during the production process, and the surface quality of the cast billet is qualified.

[0155] Example 5

[0156] This invention provides a method for selecting crystallizer vibration parameters during high-speed continuous casting of round billets. In this embodiment, the steel grade used is 34Mn6 (C: 0.30~0.40), with a cross-sectional diameter of φ240mm. The crystallizer vibration waveform is sinusoidal, and the crystallizer vibration equipment can achieve a vibration frequency of 0~260min. -1 The frequency and amplitude of the vibration are 0-6 mm.

[0157] Before the speed increase, the casting machine's pulling speed was 2.0 m / min. Numerical simulation was used to calculate the solidification process and various production indicators to determine the solidification endpoint and the metallurgical length of the casting machine after the speed increase. The performance of the casting machine was also evaluated, and it was finally determined that the maximum pulling speed of the No. 6 casting machine could be increased to 3.6 m / min.

[0158] At the original pulling speed of 2.0 m / min, the negative slip time is 0.14 s. Considering the reduced consumption of protective slag and the influence of vibration mark depth at high pulling speeds, the negative slip time at a pulling speed of 3.6 m / min is initially selected to be 0.1 to 0.12 s.

[0159] Along t N Calculate the horizontal planes at 0.1 and 0.14s, and intersect them with ft under different amplitudes S. N The curve intersects at several points. At these points, with pulling speeds of 2.0 m / min and 3.6 m / min respectively, a calculation template is created in Excel using Equation 1, and the pulling speed, amplitude, and t are input. N The calculation formula was used to try inputting different vibration frequency values ​​to obtain the negative slip time that satisfies 0.1s≤t≤0.14s. That is, the available amplitude value was obtained by projecting it onto the horizontal plane. The vibration frequency value that meets the condition was calculated by formula (1). Then, the values ​​of Z1 and Z2 were obtained by substituting the amplitude and pulling speed values ​​into formula (3). The available amplitude and vibration frequency parameters are shown in Table 13:

[0160] Table 13 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and the frequency f take values ​​in the range

[0161]

[0162] Calculate the Z-value and verify that it meets the requirements. Then, the amplitude and frequency in Table 12 are usable. Further determine that the negative slip time at a tension speed of 3.6 m / min is 0.11 s. The amplitude and frequency values ​​are shown in Table 14.

[0163] Table 14 shows the pulling speed as V. C0 With V C1 At that time, the amplitude S and frequency f values ​​under different modes

[0164]

[0165] As shown in equation (2), when the pulling speed is 2.0 m / min and the frequency is 108 Hz, the positive slip time is 0.41 s. The viscosity of the protective slag used in this embodiment is expected to be 0.5 Pa·s, and K is taken as an empirical value of 0.7. Therefore, as shown in equation (5), the protective slag consumption is about 0.2 kg / t when the pulling speed is 2.0 m / min and about 0.12 kg / t when the pulling speed is 3.6 m / min, which meets the requirements (0.1 kg / t ≤ Q < 0.5 kg / t), that is, the parameters are usable.

[0166] Based on the above method, the amplitude and frequency at tension speeds of 2.0-3.6 m / min were calculated similarly, and the data are shown in Table 15:

[0167] Table 15 Amplitude S and frequency f at different pulling speeds

[0168]

[0169]

[0170] By performing a linear fit on the data in the table, i.e., setting up a two-variable linear equation for the vibration frequency and the tension speed respectively, and substituting the data from the table above, we can obtain:

[0171]

[0172] Solving these equations, we get a = 22, b = -64, e = 4.2 or 5.9, c = -16, d = 178, m = 1.4, and n = 1.2. This gives us the forward and reverse velocity fV under different pulling speeds. C The control model is as follows:

[0173] Positive: Reverse:

[0174] The length of the sector section of the casting machine is 21m, t N Inversely proportional to the pulling speed, the first method for determining the inflection point is adopted, t N =0.12s is the selected value. Using this positive model, at a pulling speed of 3m / min, t N =0.12s, therefore, the forward mode is used for casting speeds of 0-3m / min, and the reverse mode is used for casting speeds of 3.1-3.6m / min. The equipment operates well during the production process and the surface quality of the cast billet is qualified.

[0175] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for selecting vibration parameters of a high-speed continuous casting crystallizer, characterized in that, Includes the following steps: S1. Determine the starting speed and target speed range for continuous casting; S2. Determine the negative slip time corresponding to the starting speed, and set the negative slip time t at the target speed according to the site requirements. N scope; S3. Due to negative slip time t N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N By projecting a certain value onto a horizontal plane, we can obtain the amplitude value and frequency range of the negative slip time required to achieve the target speed from the starting speed. S4. Obtain the vibration parameters using the amplitude and corresponding tension speed obtained in S3, and determine whether the vibration parameter values ​​meet the process and equipment requirements. If they do, further determine the vibration frequency based on the determined amplitude; if they do not meet the requirements, appropriately increase the amplitude value. S5. At negative slip time t N A time constant is determined within the range, and the corresponding amplitude and frequency values ​​are selected based on this constant. S6. Determine whether the slag consumption is within a reasonable range based on the selected vibration frequency. If it is, select this vibration frequency and amplitude. If not, return to S5 and repeat the process. S7. Repeat S2-S6 to obtain the amplitude, frequency and negative slip time at different tension speeds, and select the corresponding inflection point determination method according to the changing trend of negative slip time. S8. Test whether the working status of the crystallizer vibration table is normal under different pulling speeds and vibration frequencies and amplitudes. If it is operating normally, determine the corresponding amplitude and frequency as vibration parameters.

2. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 1, characterized in that, The high-speed continuous casting refers to the casting speed of square billets, round billets, slabs, rectangular billets, or other irregularly shaped billets.

3. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 1, characterized in that, Negative slip time t N The range is 0.05 to 0.25 s.

4. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 1, characterized in that, The frequency range in S3 includes a high-frequency range and a low-frequency range. A lower frequency value is selected in the high-frequency range, and a higher frequency value is selected in the low-frequency range.

5. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 4, characterized in that, The formula for calculating the vibration parameter Z is as follows: Z = 2S / Vc, where S is the amplitude and Vc is the tension speed corresponding to the amplitude.

6. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 4, characterized in that, The negative slip ratio NS in the low-frequency range is 2.4% < NS ≤ 20%, and the negative slip ratio NS in the high-frequency range is 2.4% > NS ≥ -240%.

7. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 1, characterized in that, The reasonable range for slag consumption is 0.1 to 0.5 kg / t.

8. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 2, characterized in that, The drawing speed of square billet is greater than or equal to 3.5 m / min, the drawing speed of round billet is greater than or equal to 3.0 m / min, the drawing speed of slab is greater than or equal to 1.5 m / min, the drawing speed of rectangular billet is greater than or equal to 2.0 m / min, or the drawing speed of other irregular billets is greater than or equal to 1.2 m / min.

9. The method for selecting vibration parameters of a high-speed continuous casting crystallizer according to claim 1, characterized in that, The method for determining the inflection point is specifically based on the change of tN during the increase of the pulling speed, selecting t... N The amplitude or slag consumption is used as the turning point. Positive control is used at the turning point, and reverse control is used after the turning point.

10. A vibration parameter selection system for a high-speed continuous casting crystallizer, characterized in that, The system is used to implement the selection method according to any one of claims 1-9, and the system comprises: The first determining module is used to determine the starting speed and target speed range of continuous casting. The second determining module is used to determine the negative slip time corresponding to the starting speed, and to set the negative slip time t at the target speed according to the site requirements. N scope; The third determining module is used to determine the negative slip time t. N The range yields the frequency-negative slip-time curves under different tension speeds and amplitudes, i.e., ft. N Curve, passing through the starting acceleration t N and t N By projecting a certain value onto a horizontal plane, we can obtain the amplitude value and frequency range of the negative slip time required to achieve the target speed from the starting speed. The first judgment module is used to obtain vibration parameters based on the obtained amplitude and corresponding tension speed, and to determine whether the vibration parameter values ​​meet the process and equipment requirements. If they do, the vibration frequency is further determined based on the determined amplitude; if they do not meet the requirements, the amplitude value is appropriately increased. The first selection module is used to select the negative slip time t. N A time constant is determined within the range, and the corresponding amplitude and frequency values ​​are selected based on this constant. The second judgment module is used to determine whether the slag consumption is within a reasonable range based on the selected vibration frequency. If it is, the vibration frequency and amplitude are selected; if not, the process is repeated. The fourth determination module is used to select the corresponding inflection point determination method based on the changing trend of the negative slip time, based on the amplitude, frequency and negative slip time values ​​obtained at different tension speeds. The fourth determination module is used to test whether the working status of the crystallizer vibration table is normal under different pulling speeds and vibration frequencies and amplitudes. If it is operating normally, the corresponding amplitude and vibration frequency are determined as vibration parameters.

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