CN110014130B - Control method and control system for electromagnetic stirring of steel continuous casting crystallizer - Google Patents
Control method and control system for electromagnetic stirring of steel continuous casting crystallizer Download PDFInfo
- Publication number
- CN110014130B CN110014130B CN201910426967.9A CN201910426967A CN110014130B CN 110014130 B CN110014130 B CN 110014130B CN 201910426967 A CN201910426967 A CN 201910426967A CN 110014130 B CN110014130 B CN 110014130B
- Authority
- CN
- China
- Prior art keywords
- electromagnetic stirrer
- electromagnetic
- mode
- operation mode
- stirring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
Abstract
The invention provides a control method for electromagnetic stirring of a steel continuous casting crystallizer, which comprises the following steps: step 1: the power supply frequency of the electromagnetic stirrer (1) is setThe method comprises the steps of obtaining a ratio f and a magnetic interaction index IA, and collecting technological parameters of a continuous casting process, wherein the magnetic interaction index IA is the ratio of electromagnetic force to the momentum of molten steel at a water gap outlet, and the technological parameters comprise molten steel density rho, water gap outlet average speed Vs, magnetic field characteristic length, casting blank width W, molten steel resistance R, molten steel impedance X and casting blank thickness D; step 2: calculating the electromagnetic stirring current of the electromagnetic stirrer (1)
Wherein the cross-sectional area S is W × D.
Description
Technical Field
The invention relates to an electromagnetic stirring metallurgy control method and an electromagnetic stirring metallurgy control system for a steel continuous casting crystallizer, and belongs to the field of ferrous metallurgy continuous casting production control.
Background
Continuous casting practice shows that the flow of molten steel in a crystallizer is a key factor influencing the surface and internal quality of a casting blank. The traditional method (such as changing the casting blank drawing speed, the shape of a water gap of a crystallizer and the insertion depth) has no obvious effect on improving the flow field in the crystallizer, and the non-contact electromagnetic flow control technology is widely applied to the industry because of no secondary pollution to molten steel. Wherein, the electromagnetic stirring technology of the crystallizer is taken as a necessary production process for solving the problems of the internal and surface quality of the casting blank. The electromagnetic stirring technology of the crystallizer is to stir the molten steel by utilizing the electromagnetic force generated by the interaction of an electromagnetic field and the molten steel. Therefore, through the specific magnetic field design, the crystallizer can be used for electromagnetically stirring certain areas in the crystallizer, the conditions of improving the heat transfer and mass transfer of molten steel in the crystallizer are achieved by changing the flow of the molten steel in the crystallizer, and the metallurgical effects of obviously improving the surface quality of a casting blank, reducing subcutaneous inclusions and bubbles, expanding the isometric crystal rate, improving the center segregation and the like can be achieved.
The metallurgical effect of the electromagnetic stirring technology of the crystallizer is closely related to the continuous casting process parameters of casting blank steel grade, section, blank drawing speed and the like. The existing electromagnetic stirring technology of the crystallizer determines the optimal operation mode, electrical parameters and installation position of the electromagnetic stirrer under the condition of assuming the continuous casting of a typical steel grade and basically unchanged casting conditions. If the continuous casting process parameters change, metallurgical process personnel can only manually adjust the electrical parameters of the electromagnetic stirrer according to experience, and the manual adjustment usually has larger error and cannot adapt to the manual adjustment. When the process parameters change, the problem of metallurgical process personnel is solved by correctly selecting the optimal stirring parameters of the electromagnetic stirrer.
However, the continuous casting process parameters in the continuous casting production process are usually difficult to be kept completely stable, the process parameters such as steel grade, casting blank section, billet drawing speed, casting temperature and the like are frequently changed, the flowing of molten steel in the crystallizer, the solidification of a blank shell and the distribution of the molten steel temperature are directly influenced, the electrical parameters of the electromagnetic stirrer cannot be correspondingly adjusted, the electromagnetic stirring technical effect of the casting blank crystallizer is greatly influenced, and therefore the final metallurgical effect of electromagnetic stirring can be directly influenced.
Disclosure of Invention
The invention provides an electromagnetic stirring metallurgy control method for a steel continuous casting crystallizer, aiming at the problem that in the prior art, when continuous casting process parameters change, stirring parameters of an electromagnetic stirrer cannot be determined, so that the metallurgical effect of electromagnetic stirring is influenced.
In order to solve the technical problems, the invention adopts the technical scheme that: a control method for electromagnetic stirring of a steel continuous casting crystallizer comprises the following steps:
step 1: setting a power frequency f of an electromagnetic stirrer and a magnetic interaction index IA, and collecting technological parameters of a continuous casting process, wherein the magnetic interaction index IA is a momentum ratio of electromagnetic force to molten steel at a water gap outlet, and the technological parameters comprise molten steel density rho, water gap outlet average speed Vs, molten steel conductivity sigma, molten steel permeability mu, casting blank width W, molten steel resistance R, molten steel impedance X and casting blank thickness D;
step 2: calculating a first current value I according to the following formulaeAnd setting the electromagnetic stirring current of the electromagnetic stirrer to the first current value Ie
Wherein the cross-sectional area S is W × D,
ω＝2πf。
in the above technical scheme, the process parameters further include a blank drawing speed VC；
The step 1 is followed by:
step 2A: according to the withdrawal speed VCDetermining an operation mode of the electromagnetic stirrer;
preferably, when a1≤VC≤b1When the operation mode of the electromagnetic stirrer is determined to be the stirring mode, and when V is greater than V, the operation mode is determined to be the stirring modeC＞b1When the speed of the electromagnetic stirrer is reduced, the operation mode of the electromagnetic stirrer is determined to be a speed reduction mode, and when V is higher than VC＜a1If so, determining that the operation mode of the electromagnetic stirrer is an acceleration mode;
more preferably, a1＝1m/min，b1＝2m/min。
In the above technical scheme, the process parameters further include a blank drawing speed VC；
The step 1 is followed by:
and step 2B: according to the withdrawal speed VCDetermining the operation mode of the electromagnetic stirrer according to the size of the casting blank;
preferably, the mode of operation of the electromagnetic stirrer is determined on the basis of the crystallizer index Mo, when a2≤Mo≤b2When the Mo is more than b, the operation mode of the electromagnetic stirrer is determined as the stirring mode2When the speed is higher than the set speed, the operation mode of the electromagnetic stirrer is determined as the speed reduction mode, and Mo is less than a2When the temperature is higher than the preset temperature, determining the operation mode of the electromagnetic stirrer to be an acceleration mode, and calculating the crystallizer index Mo according to the following formula
Wherein g is the acceleration of gravity;
more preferably, a2＝1，b2＝2。
If the operation mode of the electromagnetic stirrer is determined only according to the throwing speed, the continuous casting steel passing amount is not considered, and the determined operation mode may have problems, so that the quality of the continuous casting billet is influenced. The operation mode of the electromagnetic stirrer is determined by utilizing the crystallizer index Mo, so that the determined operation mode of the electromagnetic stirrer is more accurate. The index Mo of the electromagnetic stirrer is determined according to two parameters of a throwing speed and a continuous casting steel passing amount, and the continuous casting steel passing amount is determined by the width of a casting blank and the thickness of the casting blank.
In the technical scheme, the relative height delta H between the top surface of the electromagnetic stirrer and the liquid level of the molten steel in the crystallizer is adjusted according to the operation mode of the electromagnetic stirrer.
In a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer is the deceleration mode.
In the technical scheme, IA is more than or equal to 1 and less than or equal to 1.5; preferably, IA ═ 1.
In the above technical solution, the control method further includes: and detecting the quality of the casting blank stirred by the electromagnetic stirrer, judging the quality grade of the casting blank, and correspondingly storing the quality grade parameter of the casting blank, the process parameter of the continuous casting process and the stirring parameter of the electromagnetic stirrer in a metallurgy database, wherein the stirring parameter of the electromagnetic stirrer comprises the operation mode of the electromagnetic stirrer, the power frequency f and the electromagnetic stirring current.
In a preferred embodiment, if the casting blank quality is judged to be unqualified, an alarm is given.
In a preferred embodiment, step 1 further includes: and judging whether the collected process parameters have the same values as the process parameters stored in the metallurgy database, and if so, performing electromagnetic stirring by using the stirring parameters corresponding to the process parameters in the metallurgy database. In a more preferred embodiment, in step 1, it is only determined whether the collected process parameters have the same value as the process parameters corresponding to the optimal casting blank quality level stored in the metallurgical database.
The invention also provides an electromagnetic stirring control system of the steel continuous casting crystallizer, wherein the crystallizer comprises a crystallizer copper plate and an electromagnet arranged outside the crystallizer copper plateThe control system also comprises a signal acquisition unit for acquiring technological parameters of the continuous casting process and a first current value I for calculatingeAnd setting the electromagnetic stirring current of the electromagnetic stirrer to the first current value IeThe signal acquisition unit is connected with the main control unit;
the first current value IeCalculated according to the following formula
Wherein f is the power frequency of the electromagnetic stirrer, IA is a magnetic interaction index, the section area S is W multiplied by D, the magnetic interaction index IA is the ratio of the electromagnetic force to the momentum of the molten steel at the water gap outlet, the process parameters comprise the molten steel density rho, the water gap outlet average speed Vs, the electric conductivity sigma of the molten steel, the magnetic conductivity mu of the molten steel, the casting blank width W, the molten steel resistance R, the molten steel impedance X and the casting blank thickness D,
ω ═ 2 π f. Is the characteristic length of the magnetic field.
Further, the main control unit is also used for calculating the crystallizer index
Determining the operation mode of the electromagnetic stirrer according to the crystallizer index Mo when a2≤Mo≤b2When the Mo is more than b, the operation mode of the electromagnetic stirrer is determined as the stirring mode2When the speed is higher than the set speed, the operation mode of the electromagnetic stirrer is determined as the speed reduction mode, and Mo is less than a2And determining the operation mode of the electromagnetic stirrer to be an acceleration mode, wherein g is the gravity acceleration.
In a preferred embodiment, a2＝1，b2＝2。
Further, the main control unit is also used for determining the relative height delta H between the top surface of the electromagnetic stirrer and the liquid level of the molten steel in the crystallizer according to the operation mode of the electromagnetic stirrer;
the control system further comprises a position sensor for measuring the height of the top surface of the electromagnetic stirrer, a first adjustment mechanism for adjusting the relative height Δ H;
in a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer is the deceleration mode.
Further, the control system further includes: and the casting blank quality detection device is used for detecting the quality of the casting blank stirred by the electromagnetic stirrer and judging the quality grade of the casting blank.
Compared with the prior art, the invention has the beneficial effects that: according to different continuous casting process parameters, the metallurgical system can intelligently match the optimal stirring parameters and stirring positions, avoids manual blind screening of the metallurgical parameters, reduces the times of metallurgical experiments, and greatly improves the working efficiency of metallurgical workers. Therefore, the invention has wide market application prospect.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 is a schematic view showing the steps of a method for controlling electromagnetic stirring in a steel continuous casting mold according to example 1 of the present invention;
FIG. 2 is a schematic step diagram of a control method for electromagnetic stirring of a steel continuous casting crystallizer according to embodiment 2 of the present invention;
FIG. 3 is a schematic step diagram of a control method for electromagnetic stirring of a steel continuous casting crystallizer according to embodiment 3 of the present invention;
FIG. 4 is a schematic step diagram of a control method of electromagnetic stirring of a steel continuous casting crystallizer according to embodiment 4 of the present invention;
FIG. 5 is a schematic diagram illustrating the positions of a mold and a casting slab according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a control system for electromagnetic stirring of a steel continuous casting crystallizer according to an embodiment of the present invention;
FIG. 7(a) is a macroscopic photograph of a cast slab obtained by conventional electromagnetic stirring;
fig. 7(b) is a low-magnification photograph of a cast slab obtained by the control method of the present invention according to one embodiment of the present invention.
In the figure, the device comprises an electromagnetic stirrer 1, an electromagnetic stirrer 2, a cooling module 3, a power supply module 4, a position sensor 5, a first adjusting mechanism 6, a casting blank 7, a crystallizer copper plate 8, a signal acquisition unit 10 and a main control unit.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Example 1
In the process of electromagnetic stirring, because the frequency of alternating current passing through the induction coil is very low, the generated electromagnetic field is a quasi-static electromagnetic field, and under the condition of neglecting displacement current, the electromagnetic stirring meets the Maxwell equation set:
from the Maxwell system of equations, the well-known induction equation in electromagnetic field theory can be obtained:
the magnetic induction B can be determined by finite element calculation. Magnetic flux
. Therefore, the electromagnetic stirring current of the electromagnetic stirrer 1 can be represented by the following formula
The magnetic interaction index IA is the momentum ratio of electromagnetic force and molten steel at a water gap outlet, and can be calculated by the following formula:
wherein B is magnetic induction (unit is T), and sigma is molten steel electric conductivity (unit is S/m); μ is the permeability of molten steel (in H/m), S is the cross-sectional area, where S is W × D, R is the molten steel resistance (in Ω), X is the molten steel impedance, D is the casting thickness, f is the frequency, W is the casting width (in m), and ρ is the molten steel density (in kg/m)3) Vs is the average speed of the outlet of the nozzle (unit is m/min), the characteristic length of the magnetic field, and sigma is the conductivity of the molten steel.
The following formula can be obtained by combining the formula (1) and the formula (2):
the applicant finds in research that the magnetic interaction index IA is the ratio of the electromagnetic force to the momentum of the molten steel at the outlet of the nozzle. The electromagnetic stirring technology of the crystallizer is to stir the molten steel by utilizing the electromagnetic force generated by the interaction of an electromagnetic field and the molten steel. The electromagnetic stirring is energized by current to generate electromagnetic force. Therefore, the electromagnetic stirrer mainly controls the flow of the molten steel through electromagnetic force, the momentum of the molten steel from the outlet of the water gap represents the flowing size of the molten steel, and the electromagnetic stirring needs large electromagnetic force to control the flow of the molten steel and can be represented through a magnetic interaction index IA, so that the stirring current can be obtained through reverse estimation by determining the value of the magnetic interaction index IA. When the technological parameters of the continuous casting process are changed, the various technological parameters can be obtained through measurement. The power supply frequency f of the electromagnetic stirrer 1 is generally set to a fixed value for a particular electromagnetic stirring, and a person skilled in the art will understand how to set the power supply frequency f of the electromagnetic stirrer 1. Because the magnetic interaction index has a functional relation with the current, under the condition that the power supply frequency is determined, the reasonable magnetic interaction index is set in the stirring process, so that under the condition that other parameter values are known, the current of the electromagnetic stirrer can be obtained through the calculation of the formula (3), and a better electromagnetic stirring effect is obtained.
The invention provides an electromagnetic stirring control system of a steel continuous casting crystallizer and a control method thereof. According to the continuous casting process parameters, such as: the optimal stirring mode, the running electrical parameters and the installation position of the electromagnetic stirrer are intelligently matched according to the process parameters of steel type, casting blank section, blank drawing speed and the like, so that the maximum effect of the electromagnetic stirring technology of the crystallizer is achieved.
The invention provides a control method for electromagnetic stirring of a steel continuous casting crystallizer. The crystallizer comprises a crystallizer copper plate 7 and an electromagnetic stirrer 1 arranged outside the crystallizer copper plate 7. As shown in fig. 1, the method for controlling electromagnetic stirring of a steel continuous casting crystallizer comprises the following steps:
step 1: setting a power frequency f and a magnetic interaction index IA of an electromagnetic stirrer 1 and collecting technological parameters of a continuous casting process, wherein the magnetic interaction index IA is a momentum ratio of electromagnetic force to molten steel at a water gap outlet, and the technological parameters comprise molten steel density rho, water gap outlet average speed Vs, molten steel conductivity sigma, molten steel permeability mu, casting blank width W, molten steel resistance R, molten steel impedance X and casting blank thickness D;
step 2: calculating a first current value I according to the following formulaeAnd the electromagnetic stirring current of the electromagnetic stirrer 1 is set to the first current value Ie
Wherein the cross-sectional area S is W × D.
And step 3: electromagnetic stirring is performed according to the electromagnetic stirring current and the operation mode of the electromagnetic stirrer 1.
In a preferred embodiment, 1. ltoreq. IA.ltoreq.1.5; preferably, IA ═ 1.
With respect to the above-mentioned process parameters of the continuous casting process, the person skilled in the art will understand how to measure these parameters. As for the nozzle outlet average velocity Vs, which is a parameter known to those skilled in the art, it is preferable that the nozzle outlet average velocity Vs is calculated using the total amount of molten steel, casting time, and nozzle tap area.
The control system for the electromagnetic stirring of the steel continuous casting crystallizer comprises a signal acquisition unit 8 for acquiring technological parameters of a continuous casting process and a control unit for calculating a first current value IeAnd the electromagnetic stirring current of the electromagnetic stirrer 1 is set to the first current value IeThe main control unit 10 of (1); the first current value IeCalculated according to the following formula
Wherein f is the power frequency of the electromagnetic stirrer 1, IA is a magnetic interaction index, the cross-sectional area S is W × D, the magnetic interaction index IA is the ratio of the electromagnetic force to the momentum of the molten steel at the nozzle outlet, and the process parameters include molten steel density ρ, nozzle outlet average speed Vs, molten steel conductivity σ, molten steel permeability μ, casting blank width W, molten steel resistance R, molten steel impedance X, and casting blank thickness D. The term nozzle is used herein to refer to a submerged entry nozzle, as will be understood by those skilled in the art. The signal acquisition unit 8 may be formed by a sensor or a conventional process parameter acquisition device in the field to acquire process parameters, and the main control unit 10 may be implemented by a computer, may be integrated in the computer, or may be implemented by a micro control chip, such as a DSP, an FPGA, or the like.
The casting blank is formed by pouring molten steel on a continuous casting machine, and at the beginning of pouring, a signal acquisition unit firstly acquires continuous casting metallurgical process parameters such as: steel type, casting blank section size and blank drawing speed.
The characteristic length of the magnetic field characterizes the penetration depth of the magnetic field in the molten steel. The magnetic field characteristic length is calculated by the following formula:
where ω is the angular frequency of the electromagnetic field, ω 2 pi f, f is the frequency of the power supply, and σ is the electrical conductivity of the molten steel. Is the characteristic length of the magnetic field.
Example 2
The present embodiment 2 differs from embodiment 1 in that: the technological parameters also comprise a throwing speed VCAnd step 2A-1 are also included after the step 1. FIG. 2 is a schematic step diagram of the metallurgical control method of example 2.
Step 2A: according to the withdrawal speed VCDetermining the operation mode of the electromagnetic stirrer 1 as one of stirring mode, decelerating mode and accelerating mode when a1≤VC≤b1When the operation mode is the stirring mode, the operation mode of the electromagnetic stirrer 1 is determined, and when V isC＞b1When the speed of the electromagnetic stirrer 1 is reduced, the operation mode is determined as the deceleration mode, and when V isC＜a1If so, determining that the operation mode of the electromagnetic stirrer 1 is an acceleration mode;
in a preferred embodiment, a1＝1m/min，b1＝2m/min。
Step 2A-1: adjusting the relative height delta H between the top surface of the electromagnetic stirrer 1 and the liquid level of the molten steel in the crystallizer according to the operation mode of the electromagnetic stirrer 1;
in a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer 1 is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the deceleration mode.
And step 3: electromagnetic stirring is performed according to the electromagnetic stirring current and the operation mode of the electromagnetic stirrer 1.
The position of the electromagnetic stirrer is determined according to the operation mode of the electromagnetic stirrer 1, and the relative position delta H between the top surface (upper edge) of the electromagnetic stirrer and the liquid surface of the molten steel is taken as a reference value by taking the liquid surface position as a datum plane.
The main control unit 10 is further configured to determine a relative height Δ H between the top surface of the electromagnetic stirrer 1 and the liquid level of the molten steel in the mold according to the operation mode of the electromagnetic stirrer 1.
The control system further comprises a position sensor 4 for measuring the height of the top surface of the electromagnetic stirrer 1, a first adjustment mechanism 5 for adjusting the relative height Δ H. Preferably, the first adjustment mechanism 5 is a hydraulic adjustment mechanism.
In a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer 1 is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the deceleration mode.
The invention provides an electromagnetic stirring control system of a steel continuous casting crystallizer, which is shown in figures 5 and 6. The crystallizer comprises a crystallizer copper plate 7 and an electromagnetic stirring system. The electromagnetic stirring system comprises an electromagnetic stirrer 1, a cooling module 2, a power supply module 3, a position adjusting module and a position sensor 4. The continuous casting billet 6 continuously passes through the crystallizer, the electromagnetic stirrer 1 is arranged outside the crystallizer copper plate 7, and the crystallizer copper plate 7 is arranged at intervals to stir the continuous casting billet 6. The cooling module 2 supplies water for cooling the electromagnetic stirrer 1, the power supply module 3 supplies control power for the electromagnetic stirrer 1, the position adjusting module is responsible for adjusting the position of the electromagnetic stirrer 1, and communication among the systems is completed under the control of a PLC.
Example 3
The present embodiment 3 differs from embodiment 1 in that: the technological parameters also comprise a throwing speed VCAnd step 2B-1 are also included after the step 1. FIG. 3 is a schematic step diagram of the metallurgical control method of example 3.
And step 2B: according to the withdrawal speed VCAnd the operation mode of the casting blank size determination electromagnetic stirrer 1 is one of a stirring mode, a deceleration mode and an acceleration mode.
The crystallizer index Mo is calculated according to the formula
Wherein g is the acceleration of gravity;
determining the operation mode of the electromagnetic stirrer 1 according to the crystallizer index MoOne of stirring mode, deceleration mode and acceleration mode, when a2≤Mo≤b2When the Mo is more than b, the operation mode of the electromagnetic stirrer 1 is determined as the stirring mode2When the speed is lower than the set speed, the operation mode of the electromagnetic stirrer 1 is determined as the deceleration mode, and Mo < a2If so, determining that the operation mode of the electromagnetic stirrer 1 is an acceleration mode;
the crystallizer index Mo is determined by two parameters of a blank drawing speed and a continuous casting steel passing amount, and the continuous casting steel passing amount is determined by the width of a casting blank and the thickness of the casting blank. When the size of the casting blank is not changed, the larger the blank drawing speed is, the deceleration mode is adopted, and the smaller the blank drawing speed is, the acceleration mode is adopted. When the drawing speed is not changed, the larger the casting blank size is, the deceleration mode is adopted, and the smaller the casting blank size is, the acceleration mode is adopted.
Step 2B-1: the relative height Δ H between the top surface of the electromagnetic stirrer 1 and the liquid level of the molten steel in the crystallizer is adjusted according to the operation mode of the electromagnetic stirrer 1.
And step 3: electromagnetic stirring is performed according to the electromagnetic stirring current and the operation mode of the electromagnetic stirrer 1.
In a preferred embodiment, a2＝1，b2＝2。
In a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer 1 is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the deceleration mode.
The position of the electromagnetic stirrer is determined according to the operation mode of the electromagnetic stirrer 1, and the relative position delta H between the top surface (upper edge) of the electromagnetic stirrer and the liquid surface of the molten steel is taken as a reference value by taking the liquid surface position as a datum plane.
The main control unit 10 is also used to calculate the crystallizer index
Determining the operation mode of the electromagnetic stirrer 1 to be one of stirring mode, deceleration mode and acceleration mode according to the crystallizer index Mo when a2≤Mo≤b2Then the operation of the electromagnetic stirrer 1 is determinedThe mode is stirring mode, when Mo is more than b2When the speed is lower than the set speed, the operation mode of the electromagnetic stirrer 1 is determined as the deceleration mode, and Mo < a2Then, the operation mode of the electromagnetic stirrer 1 is determined as the acceleration mode, where g is the gravitational acceleration. Preferably, a2＝1，b2＝2。
The main control unit 10 is further configured to determine a relative height Δ H between the top surface of the electromagnetic stirrer 1 and the liquid level of the molten steel in the mold according to the operation mode of the electromagnetic stirrer 1. The control system further comprises a position sensor 4 for measuring the height of the top surface of the electromagnetic stirrer 1, a first adjustment mechanism 5 for adjusting the relative height Δ H. Preferably, the first adjustment mechanism 5 is a hydraulic adjustment mechanism.
In a preferred embodiment, Δ H is-0.02 m when the operation mode of the electromagnetic stirrer 1 is the stirring mode, Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the acceleration mode, and Δ H is-0.1 m when the operation mode of the electromagnetic stirrer 1 is the deceleration mode.
Example 4
The present embodiment 4 differs from embodiment 1 in that: the control method further includes the following step 4. FIG. 4 is a schematic step diagram of the metallurgical control method of example 4.
And 4, step 4: and detecting the quality of the casting blank stirred by the electromagnetic stirrer 1, judging the quality grade of the casting blank, and correspondingly storing the quality grade parameter of the casting blank, the process parameter of the continuous casting process and the stirring parameter of the electromagnetic stirrer 1 in a metallurgy database, wherein the stirring parameter of the electromagnetic stirrer 1 comprises the operation mode of the electromagnetic stirrer 1, the power frequency f and the electromagnetic stirring current.
In a preferred embodiment, if the casting blank quality is judged to be unqualified in the step 3, alarming and reminding are carried out;
in a preferred embodiment, step 1 further includes: and judging whether the collected process parameters have the same values as the process parameters stored in the metallurgy database, if so, performing electromagnetic stirring by using the stirring parameters corresponding to the process parameters in the metallurgy database, and more preferably, in the step 1, only judging whether the collected process parameters have the same values as the process parameters corresponding to the optimal casting blank quality grade stored in the metallurgy database.
The control system also comprises a casting blank quality detection device which is used for detecting the quality of the casting blank stirred by the electromagnetic stirrer 1 and judging the quality grade of the casting blank. The slab quality detection device may be implemented by a sensor or other device for detecting the quality of the slab (e.g., a device for detecting the surface of the slab), as will be understood by those skilled in the art.
If the corresponding process parameters exist in the metallurgy database, the stirring parameters which are stored in the metallurgy database and correspond to the process parameters are preferably called;
if the same process parameters do not exist in the metallurgy database, the main control unit 10 is handed in to calculate and determine the operation parameters of the electromagnetic stirrer.
The casting blank quality system can detect defects in the casting blank, can communicate with the continuous casting system and the metallurgy database, and has an alarm reminding function once the casting blank quality is unqualified.
After the continuous casting billets 6 are stirred, the quality grades of the casting billets are evaluated by a quality detection system, unqualified casting billets are subjected to alarm reminding processing, and the judged quality grades of the qualified casting billets are correspondingly transmitted to an electromagnetic metallurgy database to be stored one by one with the process participation and the operation parameters of an electromagnetic stirrer for the next production link to call.
The casting blank stirred by the electromagnetic stirring system adopts the prior patent CN 205038190U, the quality detection of the casting blank detection system is adopted to judge the quality grade of the casting blank, the unqualified casting blank is warned, the qualified casting blank is judged according to the quality grade, and the specific inspection standard is executed according to the YB/T4003 and 2016 continuous casting steel casting blank macrostructure defect grade chart. And transmitting the quality grade signal to a metallurgy database. And (3) operating the electromagnetic stirrer, continuously passing the continuous casting billets 6 through the electromagnetic stirrer, detecting the stirred casting billets by a casting billet quality detection device, and judging the quality grade of the casting billets.
The control system of the present invention includes: the device comprises a casting blank, a continuous casting machine, a continuous casting control system, an electromagnetic stirring system, a signal acquisition unit 8, a main control unit 10 and a casting blank quality detection device. The continuous casting control system is a master control system of continuous casting equipment and is used for controlling the adjustment and management of each process parameter; the electromagnetic stirring system comprises an electromagnetic stirrer 1, a cooling module 2, a power supply module 3 and a position adjusting module; the electromagnetic stirrer 1, the cooling module 2, the position sensor 4 and the first adjusting mechanism 5 are all communicated with the power module 3 through PLC control and complete control actions. The first adjusting mechanism 5 is mainly responsible for adjusting the position of the electromagnetic stirrer on the continuous casting machine.
The intelligent metallurgical system control method comprises the following steps:
the data acquisition system acquires technological parameters of the continuous casting process from the continuous casting control system, such as: the method comprises the following steps of (1) establishing process parameters such as steel type, section and throwing speed through a mapping relation, tracking and storing the process parameters and the final casting blank metallurgical effect, and respectively calculating the selected parameters to obtain corresponding electromagnetic stirring operation parameters;
and performing simple function judgment on the acquired process parameters and the process parameters in the metallurgy database, and executing the set of process parameters corresponding to the electromagnetic stirring operation parameters if the same process parameters exist in the database. If the same process parameters do not exist in the database, the collected process parameters are transmitted and the main control unit 10 calculates the matched electromagnetic stirring operation parameters.
After the power module 3 in the electromagnetic stirring system receives the electromagnetic stirrer position and the signals of the electromagnetic stirrer operation parameters, the position adjusting module executes the electromagnetic stirring body to move to the signal position. The power supply outputs corresponding electrical parameters, and the electromagnetic stirring system works and operates;
after the position of the electromagnetic stirrer is determined, the position sensor 4 detects the current position of the electromagnetic stirrer 1, and the first adjusting mechanism 5 moves the electromagnetic stirrer 1 to the specified position.
The casting blank grade signal parameters, the process parameters and the stirring parameters are stored in a metallurgy database in a one-to-one correspondence mode so as to be called preferentially in the next production cycle.
The control method of the present invention involves the following steps: step 1, step 2, step 3 and step 4 are executed in sequence. The step 1, the step 2A-1 and the step 4 are executed in sequence. Step 1, step 2B-1, step 3 and step 4 are executed in sequence. And step 2A and step 2B are executed by selecting one of the steps. Step 2A (or step 2B) and step 2 may be performed simultaneously, or step 2A (or step 2B), step 2 may be performed sequentially, or step 2, step 2A (or step 2B) may be performed sequentially.
In the present invention, the nozzle means a submerged entry nozzle.
In one embodiment, the invention of the invention is used for producing 42CrMoA steel by continuous casting, and the technological parameters of the continuous casting process are as follows: the average speed Vs of the outlet of the water gap is 0.311m/min, and the blank drawing speed VC1.0m/min, nozzle diameter phi 80mm, and billet size 1.600mm (length) × 0.230mm (thickness). Referring to FIGS. 7(a) and 7(b), there are photographs of 42CrMoA steel slabs obtained by the control method of the present invention without using the method of the present invention.
When the method of the invention is not used, metallurgical process personnel have fumbling randomness on the setting and the mode of the current and the position of the stirrer, in the practice of continuous casting of steel, the stirring current is 400A, the position of the stirrer is set to be delta H ═ 0m, and the operation mode of the electromagnetic stirrer is the rotating stirring mode, and the result is shown in figure 7 (a). Analysis shows that when the method is not adopted, the setting of the stirring current is random, so that the setting of the stirring current is smaller, the selection of the operation mode is wrong, and the operation mode of the electromagnetic stirrer mainly solves the problem of surface quality of the casting blank, so that the central shrinkage cavity and the like of the casting blank are caused, the central quality problem is serious, the stirring effect is poor, and the continuous casting process is not ideal.
When the control method of the electromagnetic stirring of the steel continuous casting crystallizer is adopted, the magnetic interaction index IA is set to be 1, the power supply frequency f is set to be 4Hz, and the process parameters of the continuous casting process are determined according to the process parameters of the continuous casting process
The stirring current is calculated to be 500A, and the crystallizer index Mo is calculated to be 0.89 < 1 according to the casting speed and the casting blank size, so that the operation mode of the electromagnetic stirrer is the addition modeIn the velocity mode, the position of the electromagnetic stirrer 1 was moved to a position where Δ H is-0.1 m, and the result is shown in fig. 7 (b).
Comparing fig. 7(a) and fig. 7(b), it can be seen that the central shrinkage cavity of the casting blank is eliminated and the internal quality is obviously improved by adopting the method of the present invention.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention should be covered by the present patent. After reading this disclosure, modifications of various equivalent forms of the present invention by those skilled in the art will fall within the scope of the present application, as defined in the appended claims. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Claims (21)
1. A control method for electromagnetic stirring of a steel continuous casting crystallizer, wherein the crystallizer comprises a crystallizer copper plate (7) and an electromagnetic stirrer (1) arranged outside the crystallizer copper plate (7), and is characterized by comprising the following steps:
step 1: setting a power frequency f and a magnetic interaction index IA of an electromagnetic stirrer (1) and acquiring process parameters of a continuous casting process, wherein the magnetic interaction index IA is the ratio of the electromagnetic force to the momentum of molten steel at a water gap outlet, and the process parameters comprise molten steel density rho, water gap outlet average speed Vs, molten steel conductivity sigma, molten steel permeability mu, casting blank width W, molten steel resistance R, molten steel impedance X and casting blank thickness D;
step 2: calculating a first current value I according to the following formulaeAnd setting the electromagnetic stirring current of the electromagnetic stirrer (1) to the first current value Ie
Wherein the cross-sectional area S is W × D,
ω＝2πf。
2. the control method according to claim 1, characterized in that said process parameters further comprise a withdrawal speed VC；
The step 1 is followed by:
step 2A: according to the withdrawal speed VCThe operating mode of the electromagnetic stirrer (1) is determined.
3. The control method according to claim 2, wherein when a is1≤VC≤b1When the operation mode of the electromagnetic stirrer (1) is the stirring mode, when V isC＞b1When the speed is higher than the set speed, the operation mode of the electromagnetic stirrer (1) is determined to be a deceleration mode, and when V is higher than the set speed, the operation mode is determined to be a deceleration modeC＜a1And then determining that the operation mode of the electromagnetic stirrer (1) is an acceleration mode.
4. A control method according to claim 3, characterized in that a1＝1m/min，b1＝2m/min。
5. The control method according to claim 1, characterized in that said process parameters further comprise a withdrawal speed VC；
The step 1 is followed by:
and step 2B: according to the withdrawal speed VCAnd determining the operation mode of the electromagnetic stirrer (1) according to the size of the casting blank.
6. The control method according to claim 5, wherein in step 2B, the operation mode of the electromagnetic stirrer (1) is determined according to the crystallizer index Mo when a2≤Mo≤b2When it is, thenDetermining the operation mode of the electromagnetic stirrer (1) as a stirring mode when Mo is more than b2When the speed is higher than the set speed, the operation mode of the electromagnetic stirrer (1) is determined as a deceleration mode, and Mo < a2When the temperature is higher than the set temperature, determining the operation mode of the electromagnetic stirrer (1) as an acceleration mode, and determining the crystallizer index Mo according to the following formula
Wherein g is the acceleration of gravity.
7. Control method according to claim 6, characterized in that a2＝1，b2＝2。
8. The control method according to any one of claims 2 to 7, characterized in that the relative height Δ H between the top surface of the electromagnetic stirrer (1) and the liquid level of the molten steel in the mold is adjusted according to the mode of operation of the electromagnetic stirrer (1).
9. The control method according to claim 8, wherein Δ H is-0.02 m if the operation mode of the electromagnetic stirrer (1) is the stirring mode, Δ H is-0.1 m if the operation mode of the electromagnetic stirrer (1) is the acceleration mode, and Δ H is-0.1 m if the operation mode of the electromagnetic stirrer (1) is the deceleration mode.
10. The control method according to claim 1, wherein 1. ltoreq. IA.ltoreq.1.5.
11. The control method according to any one of claims 1 to 7, characterized by further comprising: the quality of the casting blank stirred by the electromagnetic stirrer (1) is detected, the quality grade of the casting blank is judged, and the quality grade parameters of the casting blank, the technological parameters of the continuous casting process and the stirring parameters of the electromagnetic stirrer (1) are correspondingly stored in a metallurgy database, wherein the stirring parameters of the electromagnetic stirrer (1) comprise the operation mode of the electromagnetic stirrer (1), the power frequency f and the electromagnetic stirring current.
12. The control method according to claim 11, wherein if the casting blank quality is judged to be unqualified, an alarm is given.
13. The control method according to claim 11, wherein the step 1 further comprises: and judging whether the collected process parameters have the same values as the process parameters stored in the metallurgy database, and if so, performing electromagnetic stirring by using the stirring parameters corresponding to the process parameters in the metallurgy database.
14. The control method according to claim 13, wherein in the step 1, it is determined whether the collected process parameters have the same value as the process parameters corresponding to the optimal slab quality grade stored in the metallurgical database.
15. The control system for the electromagnetic stirring of the steel continuous casting crystallizer comprises a crystallizer copper plate (7) and an electromagnetic stirrer (1) arranged on the outer side of the crystallizer copper plate (7), and is characterized by further comprising a signal acquisition unit (8) for acquiring technological parameters of a continuous casting process and a first current value I for calculatingeThe main control unit (10) is used for setting the electromagnetic stirring current of the electromagnetic stirrer (1) to be the first current value, and the signal acquisition unit is connected with the main control unit (10);
the first current value IeCalculated according to the following formula
Wherein f is the power frequency of the electromagnetic stirrer (1), IA is a magnetic interaction index, the cross-sectional area S is W multiplied by D, the magnetic interaction index IA is the ratio of the electromagnetic force to the momentum of the molten steel at the water gap outlet, and the process parameters comprise the molten steel density rho, the water gap outlet average speed Vs, the electric conductivity sigma of the molten steel, the magnetic conductivity mu of the molten steel, the casting blank width W, the molten steel electrokinetic energyR resistance, molten steel impedance X, casting blank thickness D,
ω＝2πf。
16. the control system of claim 15,
the main control unit (10) is also used for calculating the crystallizer index
VCFor the withdrawal speed, the mode of operation of the electromagnetic stirrer (1) is determined on the basis of the crystallizer index Mo, when a2≤Mo≤b2When the Mo is larger than b, the operation mode of the electromagnetic stirrer (1) is determined as the stirring mode2When the speed is higher than the set speed, the operation mode of the electromagnetic stirrer (1) is determined as a deceleration mode, and Mo < a2And then determining that the operation mode of the electromagnetic stirrer (1) is an acceleration mode, wherein g is the acceleration of gravity.
17. The control system of claim 16, wherein a2＝1，b2＝2。
18. The control system according to claim 16 or 17,
the main control unit (10) is also used for determining the relative height delta H between the top surface of the electromagnetic stirrer (1) and the liquid level of the molten steel in the crystallizer according to the operation mode of the electromagnetic stirrer (1);
the control system further comprises a position sensor (4) for measuring the height of the top surface of the electromagnetic stirrer (1), a first adjustment mechanism (5) for adjusting the relative height Δ H.
19. The control system according to claim 18, wherein Δ H is-0.02 m if the operation mode of the electromagnetic stirrer (1) is the stirring mode, Δ H is-0.1 m if the operation mode of the electromagnetic stirrer (1) is the acceleration mode, and Δ H is-0.1 m if the operation mode of the electromagnetic stirrer (1) is the deceleration mode.
20. The control system of any one of claims 15-17, 19, further comprising:
and the casting blank quality detection device is used for detecting the quality of the casting blank stirred by the electromagnetic stirrer (1) and judging the quality grade of the casting blank.
21. The control system of claim 18, further comprising:
and the casting blank quality detection device is used for detecting the quality of the casting blank stirred by the electromagnetic stirrer (1) and judging the quality grade of the casting blank.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910426967.9A CN110014130B (en) | 2019-05-22 | 2019-05-22 | Control method and control system for electromagnetic stirring of steel continuous casting crystallizer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910426967.9A CN110014130B (en) | 2019-05-22 | 2019-05-22 | Control method and control system for electromagnetic stirring of steel continuous casting crystallizer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110014130A CN110014130A (en) | 2019-07-16 |
| CN110014130B true CN110014130B (en) | 2020-10-20 |
Family
ID=67194234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910426967.9A Active CN110014130B (en) | 2019-05-22 | 2019-05-22 | Control method and control system for electromagnetic stirring of steel continuous casting crystallizer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110014130B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110750868A (en) * | 2019-09-20 | 2020-02-04 | 北京科技大学 | Method and system for predicting macrosegregation in continuous casting process on line |
| DE102022209148A1 (en) * | 2022-09-02 | 2024-03-07 | Sms Group Gmbh | Continuous casting device and method for continuously casting a metal strand using a continuous casting mold |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0871716A (en) * | 1994-09-08 | 1996-03-19 | Nippon Steel Corp | Method for controlling molten steel flow in mold in continuous casting |
| CN1116138C (en) * | 1995-02-28 | 2003-07-30 | 日本钢管株式会社 | Method of controlling continuous casting and apparatus thereof |
| JP3504649B2 (en) * | 2001-02-28 | 2004-03-08 | 株式会社神戸製鋼所 | Method and apparatus for electromagnetic stirring in a continuous casting mold |
| CN201217067Y (en) * | 2008-07-16 | 2009-04-08 | 上海大学 | Electromagnetic control apparatus for flow field of continuous casting crystallizer |
| CN102554172A (en) * | 2010-12-15 | 2012-07-11 | 鞍钢股份有限公司 | Dynamic control method for slab continuous casting electromagnetic stirrer |
| KR101277686B1 (en) * | 2011-06-29 | 2013-06-21 | 현대제철 주식회사 | Device for decreasing surface defect of hot coil and method therefor |
| CN102921916B (en) * | 2012-10-30 | 2014-07-30 | 鞍钢股份有限公司 | Dynamic control method for electromagnetic braking device of crystallizer |
| JP6625065B2 (en) * | 2014-05-21 | 2019-12-25 | ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． | Non-contact control of molten metal flow |
| CN104690242B (en) * | 2015-02-05 | 2017-02-22 | 东北大学 | Dynamic control method for electromagnetic stirring position at solidification end in continuous casting of steel |
| CN108284208B (en) * | 2017-01-09 | 2020-01-31 | 宝山钢铁股份有限公司 | self-adaptive pulling speed change electromagnetic stirring system and stirring method |
-
2019
- 2019-05-22 CN CN201910426967.9A patent/CN110014130B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110014130A (en) | 2019-07-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6430467B2 (en) | Slab quality prediction apparatus and method | |
| CN110014130B (en) | Control method and control system for electromagnetic stirring of steel continuous casting crystallizer | |
| JP3386051B2 (en) | Method for estimating flow pattern of molten steel in continuous casting, temperature measuring device for mold copper plate, method for determining surface defects of continuous cast slab, method for detecting molten steel flow, method for evaluating non-uniformity of heat removal in mold, method for controlling molten steel flow, Quality control method in continuous casting, continuous casting method of steel, estimation method of molten steel flow velocity | |
| JP2014147976A (en) | Control system, device and method for controlling flow of liquid metal in metal casting machine | |
| CN112371936A (en) | Continuous casting solidification end point calculation method and system | |
| CN104999043A (en) | Online measuring device and method for opening degree of sliding nozzle of continuous casting ladle | |
| CN102029368A (en) | Method for online detecting solid-liquid phase fraction and solidified tail end of secondary cooling zone of continuous casting blank | |
| KR102241467B1 (en) | Continuouse caster, system and method for controlling flow of moltensteel | |
| JP4700466B2 (en) | Continuous casting apparatus and flow velocity measuring method | |
| JP2007268559A (en) | Method and apparatus for controlling solidification completion position of continuously cast slab and method for producing continuously cast slab | |
| Blazek et al. | The development of a continuous rheocaster for ferrous and high melting point alloys | |
| CN111872338B (en) | Method for judging flow field form of slab crystallizer | |
| CN1330439C (en) | Control system, computer program product, device and method | |
| CN113500173A (en) | Control method for molten steel flow field form of medium-section slab crystallizer | |
| CN113423521B (en) | Control method for continuous casting machine, control device for continuous casting machine, and method for producing cast piece | |
| CN110794882A (en) | Front box liquid level control system and use method thereof | |
| JP4972776B2 (en) | Flow control method for molten steel in mold and surface quality judgment method for continuous cast slab | |
| JP4414609B2 (en) | Method and apparatus for detecting drift in molten steel in continuous casting of steel | |
| KR20130099289A (en) | Device for predicting quality of plate in continuous casting and method therefor | |
| WO2020170836A1 (en) | Control method for continuous casting machine, control device for continuous casing machine, and manufacturing method for cast slab | |
| CN100408228C (en) | Technology of on-line control molten steel flow in crystallizer | |
| JP4398848B2 (en) | Steel continuous casting mold flow velocity measuring apparatus and detection method | |
| KR20120011493A (en) | Apparatus for measuring a flow of surface portion in molten steel, control system and method therefor | |
| CN117139582A (en) | Method and system for improving flow velocity near molten steel surface by rapid optimization process | |
| CN115401178A (en) | Screw-down process determination method for improving internal quality of gear steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |