Post-rolling cooling control method based on high-speed wire overlap state

Abstract

The present invention discloses a post-rolling cooling control method based on the overlapping state of high-speed wires, including the following steps: 1. Collecting product information on the roller and generating a product tracking queue; 2. Calculating the coil overlapping information on each roller control section according to the product tracking queue; 3. Calculating the temperature distribution of the overlapping points and non-overlapping points, and judging the phase change position intervals of the overlapping points, non-overlapping points and the entire process; 4. When the coil is finished spinning, traversing and calculating the temperature change of the entire air-cooling process, and determining the air-cooling process with the highest consistency in the phase change process between the overlapping points and the non-overlapping points; 5. Combining the product tracking queue and the air-cooling process with the highest consistency to realize dynamic process setting. The present invention can track the overlapping state of the spinning coil on the roller online, and adjust the process parameters of the cooling equipment according to the temperature phase change process of the overlapping points and the non-overlapping points, so as to reduce the difference in the phase change cooling process of the overlapping points and the non-overlapping points, and improve the consistency of the organizational performance of the high-speed wire air-cooled products.

Description

Technical Field

[0001] The invention relates to a heat processing method for a high-speed wire, and in particular to a post-rolling cooling control method based on the overlapping state of the high-speed wire. Background Art

[0002] The hot working process of high-speed wire (the spinning speed can reach up to 140m / s) mainly includes: billet heating, rolling deformation and post-rolling cooling. The rolled wire is spun into a ring shape by the spinning machine and distributed to the conveyor roller in the form of loose coils. It is evenly cooled according to the cooling fan air volume and roller speed given by the process to meet the cooling rate required by the process, and finally completed with coiling, transportation, bundling, etc. Among them, the post-rolling cooling temperature and speed of the wire determine the intrinsic structure and mechanical properties of the wire. In actual production, due to the overlap points between the coils and the fluctuations in the control parameters during the production process, the cooling process at different positions of the coil is different, and the performance difference of the same coil of the wire cannot be completely eliminated. In the prior art, the temperature at different positions of the coil is made more uniform by adjusting the fan air volume at the edge and middle of the coil, but the adjustment value of the fan air volume is a fixed value, and dynamic adjustment cannot be achieved, and the adjustment effect is not good.

[0003] Chinese invention patent ZL200810032334.1 discloses a Stelmor wire cooling method and cooling device for a high-speed wire rolling mill, and specifically discloses: fans are symmetrically arranged above and below the wire to accelerate cooling and improve the uniformity of wire cooling. However, due to the different temperature phase changes between the overlap point and the non-overlap point, the method of cooling with upper and lower fans simultaneously cannot solve the problem of performance differences of the same coil.

[0004] Chinese invention patent ZL201010110285.6 discloses a Stelmor wire cooling method with temperature as a direct control parameter, and specifically discloses: predicting the wire temperature through a neural network, and combining the established optimal cooling temperature curve to achieve dynamic adjustment of the cooling fan air volume during the air cooling process. This method predicts the wire temperature based on the chemical composition of the wire and the ambient temperature, without considering the temperature difference between the overlapped points and the non-overlapped points between the wires, and cannot solve the problem of performance differences of the same coil.

[0005] Chinese utility model patent ZL201420462955.4 discloses a steel wire air cooling line, and specifically discloses: the infrared temperature probe detects the infrared radiation of the high-temperature wire to detect the wire temperature, and feeds back to the control system to avoid the air flow temperature change affecting the detection result of the temperature probe, thereby achieving more accurate control of the wire cooling. This patent uses temperature detection means to assist process control, but does not display product phase change information, so it is impossible to more accurately adjust the air cooling process according to the phase change information, and it is impossible to solve the performance differences of the same circle of products caused by the different phase change processes of the overlap point and the non-overlap point, and it is also impossible to automatically achieve automatic process optimization. Summary of the invention

[0006] The purpose of the present invention is to provide a post-rolling cooling control method based on the overlapping state of high-speed wire, which can track the overlapping state of the wire laying coil on the roller online, and adjust the process parameters of the cooling equipment according to the phase change process of the overlapping point and the non-overlapping point, thereby reducing the difference in the phase change cooling process of the overlapping point and the non-overlapping point, and improving the consistency of the organizational performance of the high-speed wire air-cooled product.

[0007] The present invention is achieved in that:

[0008] A post-rolling cooling control method based on the overlapping state of high-speed wire rods, the post-rolling cooling control method is implemented by a product position tracking module, an overlapping state tracking module, a temperature tracking module, an optimal process calculation module and an air cooling process setting module integrated in a production process control system;

[0009] The post-rolling cooling control method based on the high-speed wire lap state comprises the following steps:

[0010] Step 1: The product position tracking module collects the product information corresponding to the coil on the air-cooled roller in real time and generates a product tracking queue;

[0011] Step 2: The overlapping state tracking module calculates the coil overlapping information on each roller control section in real time according to the product tracking queue;

[0012] Step 3: The temperature tracking module calculates the temperature distribution and phase change information of the overlapping points and non-overlapping points of the coil in real time, and determines the phase change position interval of the overlapping points, the phase change position interval of the non-overlapping points and the phase change position interval of the entire process according to the temperature distribution;

[0013] Step 4: When the coil spinning is finished, the optimal process calculation module traverses and calculates the temperature changes of the overlap points and non-overlap points in the entire air cooling process according to the given air cooling process standard, and determines the air cooling process with the highest consistency between the overlap point phase change process and the non-overlap point phase change process according to the phase change position interval;

[0014] Step 5: The air cooling process setting module combines the product tracking queue and the most consistent air cooling process obtained in step 4 to achieve dynamic setting of the air cooling process.

[0015] The step 1 comprises:

[0016] Step 1.1: The product position tracking module obtains the spinning start signal of the coil, establishes a product tracking queue on the air-cooled roller, adds the product information corresponding to the currently spinning coil to the head of the product tracking queue, and initializes the product information;

[0017] Step 1.2: The product position tracking module obtains the unwinding signal of the coil located at the end of the product tracking queue, and removes the product information corresponding to the coil from the product tracking queue;

[0018] Step 1.3: The product position tracking module obtains the periodic excitation signal, calculates and updates the positions of all coils. The calculation formula is as follows:

[0019] Pos(i,N)=Pos(i,N-1)+V(k)×t1 Formula (1)

[0020] Among them, Pos(i,N) is the position of the coil with coil number i in the Nth cycle of the excitation signal, the unit is m;

[0021] Pos(i,N-1) is the position of the excitation signal of the coil with coil number i in the N-1th cycle, in m;

[0022] k is the number of the roller control section, V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s;

[0023] t1 is the time interval of the periodic excitation signal, in seconds.

[0024] The product information includes the following information: coil number, steel type, wire diameter, spinning circle diameter, spinning temperature, spinning speed, air cooling process standard, spinning time, current position, and initial position.

[0025] The step 2 comprises:

[0026] Step 2.1: The overlap state tracking module calculates the overlap number n of all coils on each roller control section. The total number of overlap points between the current coil and other coils is 4n. The calculation formula of n is:

[0027] n=D / W formula (2)

[0028] Wherein, D is the spinning circle diameter;

[0029] W is the distance between adjacent coils, and its calculation formula is: W = 3.14159 × V (k) × D / V0 Formula (3)

[0030] Among them, V0 is the spinning speed;

[0031] V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s;

[0032] Step 2.2: Define the running direction of the coil on the roller as the X-axis, define the direction perpendicular to the X-axis as the Y-axis, project the jth overlap point onto the Y-axis, the value range of j is [1, n], and calculate the overlap point P j The Y-axis coordinate H j , thus obtaining the position distribution of n overlapping points on the Y axis;

[0033] The overlapping point P j The Y-axis coordinate H j The calculation formula is:

[0034] H j =[(D / 2) 2 -(j×W / 2) 2 ] 1 / 2 Formula (4).

[0035] The step 3 comprises:

[0036] Step 3.1: Calculate the first surface heat transfer coefficient hr1 of the non-overlapping point. The calculation formula is:

[0037] h r1 =1.25u 0.25 (G r ×P r ) 0.35 Formula (5)

[0038] Among them, u is the cooling wind speed, the unit is m / s, and its calculation formula is:

[0039]

[0040] Where P is the power of the cooling equipment, which is determined by the characteristics of the air cooling equipment and the air cooling process standards;

[0041] a0, a1, and a2 are regression coefficients, which are determined by the characteristics of the air-cooling equipment;

[0042] δ is the proportion of the middle or side of the coil to the output air volume of the cooling fan: when calculating the cooling air speed in the middle of the coil, δ uses the proportion of the middle of the coil to the output air volume of the cooling fan; when calculating the cooling air speed at the side of the coil, δ uses the proportion of the side of the coil to the output air volume of the cooling fan;

[0043] G r is the Grashof number;

[0044] P r is the Prandtl number at room temperature;

[0045] Step 3.2: Calculate the second surface heat transfer coefficient h of the overlap point r2 , the calculation formula is:

[0046]

[0047] Among them, κ is the correction coefficient. When the overlap number n changes, κ>1. When the overlap number n remains unchanged, is the heat transfer coefficient of the second overlap point at different overlap densities h r2 Impact

[0048] R is the wire radius, in m;

[0049] λ is the thermal conductivity of the cooling medium, i.e. air, in W / (mK);

[0050] Re f is the Reynolds number corresponding to the average temperature of the ambient temperature and the surface temperature of the coil overlap point;

[0051] Pr f The corresponding temperature is the average of the ambient temperature and the surface temperature of the coil junction. r value;

[0052] Pr s The corresponding temperature is the Prandtl number P of the surface temperature of the coil joint. r value;

[0053] Step 3.3: Calculate the coil temperature. The calculation model is:

[0054]

[0055] Where T is temperature, t is time, r is the calculation radius, and the value range of r is [0, R];

[0056] a is the thermal conductivity of the coil, in W / (mK);

[0057] c p is the specific heat of the coil, in J / kg.K;

[0058] ρ is the density of the coil, in kg / m 3 ;

[0059] g(T) is the phase transformation heat of austenite to ferrite and pearlite, and its calculation formula is:

[0060]

[0061] Where H(T) is the phase change heat, in J·kg -1 .

[0062] X is the phase change variable, and its calculation formula is: X = 1-exp(-bt2 m ) Formula (10)

[0063] in, T1 is the current temperature, t2 is the transition time, m = 0.99;

[0064] △X is the phase change variable increment of the phase change variable X within the time △t;

[0065] The initial conditions of formula (8) are: T = 0, 0 ≤ r ≤ R

[0066] T = T0(r);

[0067] Among them, T0 is the spinning temperature of the coil;

[0068] The boundary conditions of formula (8) are:

[0069]

[0070] Among them, T air is the ambient temperature; h r is the first surface heat transfer coefficient h r1 Or the second surface heat transfer coefficient h r2 ;

[0071] Step 3.4: The product position tracking module obtains the wire-spinning end signal and the wire-spinning performance, and the optimal process calculation module traverses and calculates the temperature distribution of the wire from spinning to unwinding under the air cooling process standard;

[0072] Step 3.5: According to the temperature distribution of the wire, determine the start and end time of the phase change at the overlap point and the phase change at the non-overlap point;

[0073] Step 3.6: Calculate the phase change position interval of the overlapping points, the phase change position interval of the non-overlapping points and the phase change position interval of the entire phase change process. The phase change position interval of the entire phase change process is the combined interval of the phase change position interval of the overlapping points and the phase change position interval of the non-overlapping points.

[0074] In step 3.5, the criterion for determining the start time of the phase change process is:

[0075]

[0076] Among them, △ti The coil temperature is T i The calculation time step is ;

[0077] τ i The coil temperature is T i The phase transition incubation time;

[0078] f(ε) is the function of the accumulated strain in the phase change material;

[0079] When formula (11) is satisfied, the phase change process is considered to have started; when the phase change amount X>0.99, the phase change is considered to have ended.

[0080] In step 4, the criterion for judging the consistency between the phase change process at the overlap point and the phase change process at the non-overlap point is: within the given air cooling process standard range, the higher the overlap rate between the phase change interval at the overlap point and the phase change interval at the non-overlap point or the narrower the position interval of the entire phase change process, the higher the consistency between the phase change process at the overlap point and the phase change process at the non-overlap point.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] 1. The present invention uses an overlapping state tracking module to track and calculate the overlapping state of the coil on the roller in real time, so that the overlapping point information between the coils in the entire high-speed wire air cooling process can be visualized, thereby guiding the adjustment of the process parameters of the corresponding air cooling equipment based on the overlapping point information, making the adjustment of the process parameters more targeted and accurate.

[0083] 2. The present invention uses a temperature tracking module to track and calculate the phase change process of the overlap points and non-overlap points of the high-speed wire, so that the temperature distribution of the high-speed wire can be visualized, which is beneficial to the dynamic control of the model of the air cooling process after the high-speed wire is rolled, so that the overlap rate of the phase change position interval of the overlap point and the phase change position interval of the non-overlap point is maximized, thereby achieving the highest consistency between the phase change process of the overlap point and the phase change process of the non-overlap point, minimizing the same-circle performance difference of the high-speed wire and ensuring the quality control of high-grade wire products.

[0084] The present invention can track the overlapping state of the spinning coil on the roller table online, and adjust the process parameters of the cooling equipment according to the phase change process of the overlapping point and the non-overlapping point. Within the adjustment range allowed by the fan power, coil air volume distribution and roller table speed specified by the air cooling process, the difference in the phase change cooling process of the overlapping point and the non-overlapping point is reduced, and the consistency of the phase change process of the overlapping point and the non-overlapping point is maximized, thereby improving the consistency of the same-circle organizational performance of the high-speed wire air-cooled product, thereby ensuring the production quality of the high-speed wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1It is a flow chart of the post-rolling cooling control method based on the high-speed wire lap state of the present invention;

[0086] Figure 2 It is a schematic diagram of position tracking of a certain coil in Example 1 of the post-rolling cooling control method based on the overlapping state of high-speed wire rods of the present invention;

[0087] Figure 3 It is a Y-axis coordinate distribution diagram of 31 overlapping points on the first group of rollers in Example 1 of the post-rolling cooling control method based on the overlapping state of high-speed wire rods of the present invention;

[0088] Figure 4 : is a schematic diagram of the temperature distribution of the wire in Example 1 of the post-rolling cooling control method based on the overlapping state of the high-speed wire according to the present invention (before process adjustment); wherein, "..." represents the surface temperature of the coil overlapping point, "---" represents the center temperature of the coil overlapping point, "—" represents the surface temperature of the coil non-overlapping point, and "——" represents the center temperature of the coil non-overlapping point;

[0089] Figure 5 It is a schematic diagram of the temperature distribution of the wire in Example 1 of the post-rolling cooling control method based on the overlapping state of the high-speed wire of the present invention (after process adjustment); wherein, "..." represents the surface temperature of the coil overlapping point, "---" represents the center temperature of the coil overlapping point, "—" represents the surface temperature of the coil non-overlapping point, and "——" represents the center temperature of the coil non-overlapping point. DETAILED DESCRIPTION

[0090] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0091] Please see attached Figure 1 A post-rolling cooling control method based on the overlapping state of high-speed wire rods adopts a product position tracking module, an overlapping state tracking module, a temperature tracking module, an optimal process calculation module and an air cooling process setting module; the product position tracking module, the overlapping state tracking module, the temperature tracking module, the optimal process calculation module and the air cooling process setting module can be integrated in the production process control system L2 for high-speed wire rods in the prior art, and centralized control is achieved through the production process control system L2.

[0092] The post-rolling cooling control method based on the high-speed wire lap state comprises the following steps:

[0093] Step 1: The product position tracking module collects the product information corresponding to the coil on the air-cooled roller in real time and generates a product tracking queue.

[0094] The high-speed wire is spun through the spinning machine, and several loose coils are formed on the air-cooled roller, and there are overlap points between the coils. The product information includes the following information: coil number, steel type, wire (radial cross-section) diameter, spinning circle diameter, spinning temperature, spinning speed, air-cooling process standard, spinning time, current position, initial position, etc., as shown in Table 1.

[0095] Table 1 Product tracking queue information table

[0096]

[0097] Step 1.1: The product position tracking module obtains the spinning start signal of the coil and establishes a product position tracking queue on the air-cooled roller; adds the product information corresponding to the currently spinning coil to the head of the product tracking queue and initializes the product information.

[0098] Step 1.2: The product position tracking module obtains the unwinding signal of the coil located at the end of the product tracking queue, and removes the product information corresponding to the coil from the product tracking queue.

[0099] Step 1.3: Set the excitation cycle in the product position tracking module, and trigger the real-time tracking of the coil position and the real-time calculation of the temperature through the acquired periodic excitation signal. The periodic excitation signal can be realized through a timer or other means. The product position tracking module obtains the periodic excitation signal, calculates and updates the position of all coils, and the calculation formula is as follows:

[0100] Pos(i,N)=Pos(i,N-1)+V(k)×t1 Formula (1)

[0101] Among them, Pos(i,N) is the position of the coil with coil number i in the Nth cycle of the excitation signal, the unit is m;

[0102] Pos(i,N-1) is the position of the excitation signal of the coil with coil number i in the N-1th cycle, in m;

[0103] k is the number of the roller control section, V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s;

[0104] t1 is the time interval of the periodic excitation signal, in seconds.

[0105] Step 2: The overlap status tracking module calculates the coil overlap information on each roller control section in real time according to the product tracking queue.

[0106] The overlapping state of each coil is symmetrical about the center of the coil. Consider 1 / 4 of the coil, which is overlapped with the other n coils, that is, the number of overlaps is n, and the total number of overlap points between each coil and other coils is 4n.

[0107] Step 2.1: The overlap state tracking module calculates the overlap number n of all coils on each roller control section. According to the principle of symmetry, the total number of overlap points between the current coil and other coils is 4n. The calculation formula of n is:

[0108] n=D / W formula (2)

[0109] Wherein, D is the spinning circle diameter;

[0110] W is the distance between adjacent coils, and its calculation formula is: W = 3.14159 × V (k) × D / V0 Formula (3)

[0111] Among them, V0 is the spinning speed.

[0112] V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s.

[0113] Step 2.2: Define the running direction of the coil on the roller as the X-axis, define the direction perpendicular to the X-axis as the Y-axis, and define the jth overlap point P j Project to the Y axis, the value range of j is [1, n], and calculate the overlap point P j The Y-axis coordinate H j , thus obtaining the position distribution of n overlapping points on the Y axis. Taking two adjacent coils as an example, the center of one coil is taken as the origin of the coordinate system. j The center of the two coils forms an isosceles triangle. The length of the base of the isosceles triangle is j×W, and the length of the waist of the isosceles triangle is D / 2. Then the jth overlap point P j The Y-axis coordinate H j The calculation formula is:

[0114] H j =[(D / 2) 2 -(j×W / 2) 2 ] 1 / 2 Formula (4)

[0115] From formula 4, we can know that the larger the number of overlaps n, the smaller the Y-axis coordinate Hn of the overlap point Pn, and the closer the overlap point Pn is to the middle of the coil (according to the position of the coil on the roller, the part of the coil located in the middle of the roller is the middle of the coil, and the part of the coil located at the edge of the roller is the edge of the coil). The Y-axis coordinate Hn can be used to show the overlap density state of the coil, which is convenient for operation judgment and offline process optimization analysis. The smaller the number of overlaps n, the better the air cooling effect of the coil under the same cooling process conditions.

[0116] By calculating the overlap number n and the Y-axis coordinate of the overlap point of each roller control section, and displaying the overlap number n and the Y-axis coordinate of the overlap point through a curve, the coil overlap point information during the cooling (air cooling) process after wire rolling can be visualized.

[0117] Step 3: The temperature tracking module calculates the temperature distribution and phase change information of the overlapping points and non-overlapping points of the coil in real time, and determines the phase change position interval of the overlapping points, the phase change position interval of the non-overlapping points and the phase change position interval of the entire process based on the temperature distribution, so as to realize the temperature visualization during the wire air cooling process.

[0118] Preferably, a periodic excitation method can be used to realize temperature tracking and phase change calculation. The initial temperature of the first iterative calculation of the coil is the average value of the product spinning temperature, and the result of this iterative calculation is used as the initial value of the next temperature iterative calculation.

[0119] Step 3.1: Calculate the first surface heat transfer coefficient h of the non-overlapping point r1 , the calculation formula is:

[0120] h r1 =1.25u 0.25 (G r ×P r ) 0.35 Formula (5)

[0121] Among them, u is the cooling wind speed, the unit is m / s, and its calculation formula is:

[0122]

[0123] Wherein, P is the power of the cooling equipment (usually the cooling fan), which is determined by the characteristics of the air-cooling equipment and the air-cooling process standards;

[0124] a0, a1, and a2 are regression coefficients, which are determined by the characteristics of the air-cooling equipment; preferably, 5<a0<20, 0.5<a1<1, and 1<a2<2.

[0125] δ is the proportion of the middle or side of the coil to the output air volume of the cooling fan. When calculating the cooling wind speed in the middle of the coil, δ uses the proportion of the middle of the coil to the output air volume of the cooling fan; when calculating the cooling wind speed at the side of the coil, δ uses the proportion of the side of the coil to the output air volume of the cooling fan.

[0126] G r is the Grashof number (i.e., the Grashof number, the natural convection influence number, a standard index defined in fluid dynamics, which will not be described here);

[0127] P ris the Prandtl number at room temperature (i.e., the physical property influence number, a standard index defined in fluid dynamics, which will not be repeated here).

[0128] The fluid dynamics parameters such as Gr Grashof number, Pr Prandtl number, Re Reynolds number involved in this method are all for the cooling medium air and will not be repeated in the following text.

[0129] Step 3.2: Calculate the second surface heat transfer coefficient h of the overlap point r2 , the calculation formula is:

[0130]

[0131] Among them, κ is the correction coefficient. When the overlap number n changes, κ>1. When the overlap number n remains unchanged, is the heat transfer coefficient of the second overlap point at different overlap densities h r2 impact.

[0132] R is the wire radius, in m.

[0133] λ is the thermal conductivity of the cooling medium, with the unit of W / (mK). The cooling medium in the present invention is air.

[0134] Re f The Reynolds number (i.e., the flow state criterion, a standard index defined in fluid dynamics, which will not be described here) corresponds to the average temperature of the ambient temperature and the surface temperature of the coil overlap point.

[0135] Pr f The corresponding temperature is the average of the ambient temperature and the surface temperature of the coil junction. r value.

[0136] Pr s The corresponding temperature is the Prandtl number P of the surface temperature of the coil joint. r value.

[0137] Step 3.3: Calculate the coil temperature. The coil temperature is calculated using the one-dimensional cylindrical heat conduction equation. The calculation model is:

[0138]

[0139] Formula (8) can be used to calculate the surface temperature and internal temperature of the coil, thereby obtaining the surface temperature of the overlap point, the center temperature of the overlap point, the surface temperature of the non-overlap point, and the center temperature of the non-overlap point. The specific method is: the numerical difference algorithm can be used to discretize the heat conduction partial differential equation shown in formula (8) along the two dimensions of coil radius and time, thereby calculating the temperature distribution of the coil along the radial direction at different time nodes during the cooling process, where the radius r = 0 corresponds to the surface temperature of the coil, and r = R corresponds to the center temperature of the coil. The numerical difference algorithm corresponding to formula (8) is a conventional mature algorithm and will not be repeated here.

[0140] Where T is temperature, t is time, r is the calculation radius, and the value range of r is [0, R].

[0141] a is the thermal conductivity of the coil, in W / (mK).

[0142] c p is the specific heat of the coil, in J / kg.K.

[0143] ρ is the density of the coil, in kg / m 3 .

[0144] g(T) is the phase transformation heat of austenite to ferrite and pearlite, and its calculation formula is:

[0145]

[0146] Where H(T) is the phase change heat, in J·kg -1 .

[0147] X is the phase change variable, and its calculation formula is:

[0148] X = 1-exp(-bt2 m ) Formula (10)

[0149] in, T1 is the current temperature, t2 is the transition time, and m=0.99.

[0150] △X is the phase change variable increment of the phase change variable X within the time △t.

[0151] The initial conditions of formula (8) are: T = 0, 0 ≤ r ≤ R

[0152] T=T0(r), where T0 is the spinning temperature of the coil.

[0153] The boundary conditions of formula (8) are:

[0154]

[0155] Among them, T air is the ambient temperature; h r is the first surface heat transfer coefficient h r1 Or the second surface heat transfer coefficient h r2 When calculating the temperature at the overlap point, h r =h r1 When calculating the temperature at non-overlapping points, h r =h r2 .

[0156] Step 3.4: The product position tracking module obtains the spinning end signal and the spinning performance, and the optimal process calculation module traverses and calculates the temperature distribution of the wire from spinning to unwinding under the air cooling process standard.

[0157] Step 3.5: According to the temperature distribution of the wire, determine the start and end times of the phase change process at the overlap point and the phase change process at the non-overlap point, that is, the phase change information.

[0158] The criterion for determining the start time of the phase change process is:

[0159]

[0160] Among them, △t i The coil temperature is T i The calculation time step is .

[0161] τ i The coil temperature is T i The phase change incubation time can be obtained by regression of the material isothermal transformation test data. The regression formula is Where a1 and a2 are regression coefficients.

[0162] f(ε) is a function of the accumulated strain in the phase change material. f(ε) is related to the coil deformation during the phase change process. In the cooling process of the present invention, there is basically no coil deformation, so f(ε) takes a value of 1.

[0163] During the cooling process, the coil temperature is calculated in real time at fixed time intervals and accumulated. When formula (11) is satisfied, The phase change process is considered to have started. The starting time of the phase change process at the overlap point and the non-overlap point is determined by formula (11).

[0164] When the phase change amount X>0.99, the phase change is judged to be complete.

[0165] Generally, the phase change start and end time of the overlap point lags behind the phase change start and end time of the non-overlap point, and the phase change start and end time of the center lags behind the phase change start and end time of the surface. Then the phase change position interval of the entire phase change process is generally the position interval corresponding to [the phase change start time of the non-overlap point surface, the phase change end time of the overlap point center]. Step 3.6: Calculate the phase change position interval of the overlap point, the phase change position interval of the non-overlap point, and the phase change position interval of the entire phase change process. The phase change position interval of the entire phase change process is the combined interval of the phase change position interval of the overlap point and the phase change position interval of the non-overlap point.

[0166] Step 4: When the coil spinning is completed, the optimal process calculation module traverses and calculates the temperature changes of the overlap points and non-overlap points in the entire air cooling process according to the given air cooling process standards, and determines the air cooling process with the highest consistency between the overlap point phase change process and the non-overlap point phase change process based on the phase change position range. The setting of the adjustment range is determined by the air cooling process.

[0167] The criterion for judging the consistency between the overlap point phase change process and the non-overlap point phase change process is: within a given air cooling process standard range, the higher the overlap rate between the overlap point phase change interval and the non-overlap point phase change interval or the narrower the position interval of the entire phase change process, the higher the consistency between the overlap point phase change process and the non-overlap point phase change process.

[0168] Step 5: The air cooling process setting module combines the product tracking queue and the air cooling process with the highest consistency obtained in step 4 to realize dynamic setting of the air cooling process.

[0169] Embodiment 1:

[0170] On a high-speed wire rod air-cooled roller production line, the transmission roller is provided with 12 groups of roller control sections, and 14 groups of air-cooling equipment, i.e., cooling fans, are arranged under the roller. The setting positions of the 14 groups of cooling fans under the roller can be set according to the process requirements of post-rolling cooling in the prior art, and the high-speed wire rod transmitted on the 12 groups of rollers is conventionally air-cooled by the 14 groups of cooling fans.

[0171] In this embodiment, the 12 groups of roller control sections are marked as S0-S11 respectively, and the roller speeds (in m / s) corresponding to the 12 groups of roller control sections are 1.1, 1.25, 1.3, 1.37, 1.3, 1.3, 1.24, 1.17, 1.14, 1.1, 1.03, and 0.96 respectively.

[0172] The 14 groups of cooling fans are marked as F1-F14 respectively, and the powers of the 14 groups of cooling fans (the ratio of rated power, %) are 50, 50, 50, 50, 50, 60, 60, 60, 60, 60, 0, 0, 0 respectively; the middle air volume of the 14 groups of cooling fans (the ratio of the middle air volume of the coil to the output air volume of the cooling fan, %) is 18.

[0173] The diameter of the high-speed wire after rolling and cooling is 8.5 mm, the spinning temperature of the spinning machine is 888°C, the spinning speed is 110 m / s, and the spinning circle diameter is 1.07 m.

[0174] Step 1: The product location tracking module collects product information on the air-cooled roller in real time and generates a product tracking queue.

[0175] The product information includes the following information: coil number, steel type, wire diameter, spinning circle diameter, spinning temperature, spinning speed, air cooling process, spinning time, current position, initial position and other information.

[0176] Step 1.1: The product position tracking module obtains the spinning start signal of the coil and establishes a product tracking queue on the air-cooled roller, as shown in Table 2.

[0177] Table 2 Product tracking queue information table

[0178]

[0179] The product information corresponding to the current spinning coil is added to the head of the product tracking queue, and the product information is initialized, as shown in Table 3.

[0180] Table 3 Product tracking queue information table

[0181]

[0182] Step 1.2: The product position tracking module obtains the unwinding signal of the coil at the end of the product tracking queue, and removes the product information corresponding to the coil from the product tracking queue, as shown in Table 4.

[0183] Table 4 Product tracking queue information table

[0184]

[0185]

[0186] Step 1.3: The product position tracking module obtains the periodic excitation signal and calculates and updates the positions of all coils according to the formula (1) Pos(i,N)=Pos(i,N-1)+V(k)×t1. The position tracking of a coil is as follows: Figure 2 shown.

[0187] Pos(i,N) is the position of the excitation signal of the coil with roll number i in the Nth cycle, in m; Pos(i,N-1) is the position of the excitation signal of the coil with roll number i in the N-1th cycle, in m; k is the number of the roller control section, k = [0,10], V(k) is the roller speed of the roller control section numbered k in the N-1th cycle excitation signal, in m / s; t1 is the time interval of the periodic excitation signal, t1 = 2s.

[0188] Step 2: The overlap status tracking module calculates the coil overlap information on each roller control section in real time according to the product tracking queue.

[0189] Step 2.1: The overlapping state tracking module calculates the overlapping number n of all coils on each roller control section. Taking the first roller group S0 as an example, according to formula (3), W = 3.14159 × V (k) × D / V0 = 0.033598m is calculated. According to formula (2), n = D / W = 31 is calculated. The total number of overlapping points is 31 × 4 = 124.

[0190] The overlap numbers n of the 12 sets of rollers are 31, 28, 26, 25, 26, 26, 28, 29, 30, 31, 33, and 36. From the calculation results, the closer to the edge of the roller, the greater the overlap density, and the worse the cooling effect of the coil under the same cooling conditions; the closer to the middle of the roller, the smaller the overlap density, and the better the cooling effect of the coil under the same cooling conditions.

[0191] Step 2.2: Define the running direction of the coil on the roller as the X-axis, and the direction perpendicular to the X-axis as the Y-axis. j Project to the Y axis, j takes the value range [1, n], and calculate the jth overlap point P j The Y-axis coordinate H j , thus obtaining the position distribution of n overlapping points on the Y axis.

[0192] Taking the 31 overlapping points of the first set of rollers S0 as an example, the Y-axis coordinate of the first overlapping point is calculated according to formula (4): H1 = [(D / 2) 2 -(1×W / 2) 2 ] 1 / 2 = 0.5347 m. The Y-axis coordinates Hn of the 31 overlapping points of the first set of rollers S0 are shown in Table 5 and Appendix Figure 3 As shown, the coil overlap point status can be displayed in real time through curves and the like.

[0193] Table 5 Y-axis coordinate Hn values ​​of the 31 overlapping points of the first set of rollers S0

[0194]

[0195]

[0196] Step 3: The temperature tracking module calculates the temperature distribution of the wire under the standard post-rolling cooling process, and determines the phase change position interval of the overlap point, the phase change position interval of the non-overlap point and the phase change position interval of the entire process based on the temperature distribution, so as to realize the temperature visualization during the air cooling process of the wire. The temperature tracking and phase change calculation are realized by periodic excitation. The initial temperature of the first iterative calculation of the coil is the average value of the coil spinning temperature, and the result of this iterative calculation is used as the initial value of the next temperature iterative calculation.

[0197] Step 3.1: Calculate the first surface heat transfer coefficient h of the non-overlapping point according to formula (5): r1 =1.25u 0.25 (G r *P r ) 0.35 , where cooling wind speed

[0198] The cooling fan power P is 50%;

[0199] The regression coefficients a0, a1, and a2 are 10, 0.55, and 1.25, respectively;

[0200] The proportion δ of the middle part of the coil corresponding to the output air volume of the cooling fan is 18%, and the proportion δ of the edge part of the coil corresponding to the output air volume of the cooling fan is 82%.

[0201] G r is the Grashof number.

[0202] P r is the Plante number at room temperature.

[0203] Step 3.2: Calculate the second surface heat transfer coefficient h of the overlap point according to formula (7): r2 .

[0204] Among them, when the overlap number n changes, κ=1.25, and when the overlap number n remains unchanged, κ=1.

[0205] Wire diameter 2R = 8.5 mm.

[0206] λ is the thermal conductivity of air, with the unit of W / (mK). The relationship between the thermal conductivity λ of air and temperature is shown in Table 6.

[0207] Table 6 Thermal conductivity of air at different temperatures λ

[0208] Temperature ℃ Thermal conductivity W / (mK) 0 2.44E-02 100 3.21E-02 200 3.93E-02 300 4.60E-02 400 5.21E-02 500 5.74E-02 600 6.22E-02 700 6.71E-02 800 7.18E-02 900 7.63E-02 1000 8.07E-02

[0209] Re f is the Reynolds number corresponding to the average temperature of the ambient temperature and the surface temperature of the coil junction.

[0210] Pr f The corresponding temperature is the average of the ambient temperature and the surface temperature of the coil junction. r value.

[0211] Pr s The corresponding temperature is the Prandtl number P of the surface temperature of the coil joint. r value.

[0212] Among them, the ambient temperature is 30℃, and the coil surface temperature at different times is obtained by iteratively solving the heat conduction equation, as shown in Table 7.

[0213] Table 7 Calculated surface temperature of coil joint at different cooling times

[0214]

[0215]

[0216] Step 3.3: Calculate the coil temperature according to formula (8). The coil temperature is calculated using the one-dimensional cylindrical heat conduction equation. The calculation model is:

[0217]

[0218] The initial conditions are: T = 0, 0 ≤ r ≤ R

[0219] T = T0(r).

[0220] The boundary conditions are:

[0221]

[0222] Where T is temperature, t is time, r is the calculation radius, and the value range of r is [0, R].

[0223] a is the thermal conductivity of the coil, in W / (mK), which is determined by the material properties and temperature, as shown in Table 8.

[0224] Table 8 Coil thermal conductivity at different temperatures

[0225]

[0226]

[0227] c p is the specific heat of the coil, in J / kg.K.

[0228] ρ is the density of the coil, in kg / m 3 .

[0229] The phase transformation heat of austenite to ferrite and pearlite is calculated according to formula (9):

[0230] H(T) is the phase change heat, unit is J·kg -1 In this embodiment, the transformation from austenite to pearlite is considered, and H(T) is calculated using the formula H(T)=120848+52.42T-0.158T 2 Calculated.

[0231] The phase transition variable X = 1-exp(-bt2 m ).

[0232] in, T1 is the current temperature, t2 is the transition time, and m=0.99.

[0233] Step 3.4: The product position tracking module obtains the wire-spinning end signal and the wire-spinning performance. The optimal process calculation module traverses and calculates the temperature distribution of the wire from spinning to unwinding under the air cooling process standard, such as Figure 4 shown.

[0234] Step 3.5: According to the temperature distribution of the wire and formula (11), the Scheil additivity rule is used to determine the start and end times of the phase change at the overlap point and the phase change at the non-overlap point.

[0235] Step 3.6: The phase change position interval corresponding to the start and end time of the overlap point phase change is [22m, 25m], and the phase change temperature interval is [589.8℃, 620.2℃]. The phase change position interval corresponding to the start and end time of the non-overlap point phase change is [19m, 22m], and the phase change temperature interval is [586.6℃, 626.0℃]. The phase change position interval of the entire phase change process is [19m, 25m].

[0236] Step 4: When the coil spinning is finished, the optimal process calculation module traverses and calculates the temperature changes of the overlap points and non-overlap points in the entire air cooling process according to the given air cooling process, and determines the air cooling process with the highest consistency between the overlap point phase change process and the non-overlap point phase change process.

[0237] For the standard process given by the cooling equipment, the allowable adjustment of the roller speed is 0.2m / s, and the allowable adjustment of the cooling fan power and the middle air volume is 10%. According to the calculation results of step 3.7, the phase change end position is 25m, and the corresponding roller is S3 and the cooling fan is F5.

[0238] Since the cooling before and during the phase change affects the actual phase change, all control intervals before the end of the phase change are adjusted, and the process parameters of the cooling fans [F1, F5] corresponding to the roller [S0, S3] control section are adjusted: the roller speed is not adjusted, the proportion of the middle air volume of cooling fans F1 and F2 to the cooling fan output air volume is reduced to 8%, the proportion of the middle air volume of cooling fan F3 to the cooling fan output air volume is reduced to 12%, and the ratio of the fan power of cooling fans F4 and F5 to the rated power is adjusted to 55%. Other rollers and their corresponding cooling fans are not adjusted, that is, the last air cooling process setting value is retained.

[0239] Step 5: The air cooling process setting module combines the product tracking queue and the air cooling process with the highest consistency obtained in step 4, and sends the adjusted process parameter values ​​to the production process control system L2 for high-speed wire hot processing, which implements process control.

[0240] After the process of the cooling equipment is adjusted, return to step 1 to calculate the temperature distribution and phase change position interval of the subsequent coils, such as Figure 5 As shown, the phase change position interval of the overlap point is [18.5m, 23.5m], and the phase change temperature interval is [590.9℃, 627.8℃]. The phase change position interval of the non-overlap point is [19m, 23m], and the phase change temperature interval is [589.4℃, 624.2℃]. The phase change position interval of the entire phase change process is [18.5m, 23.5m]. After the cooling process is adjusted, the phase change process of the overlap point and the non-overlap point is synchronized and more consistent.

[0241] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A post-rolling cooling control method based on the overlapping state of high-speed wire rods, characterized in that: The post-rolling cooling control method is implemented by using a product position tracking module, an overlap state tracking module, a temperature tracking module, an optimal process calculation module and an air cooling process setting module integrated in a production process control system; The post-rolling cooling control method based on the high-speed wire lap state comprises the following steps: Step 1: The product position tracking module collects the product information corresponding to the coil on the air-cooled roller in real time and generates a product tracking queue; Step 2: The overlapping state tracking module calculates the coil overlapping information on each roller control section in real time according to the product tracking queue; Step 3: The temperature tracking module calculates the temperature distribution and phase change information of the overlapping points and non-overlapping points of the coil in real time, and determines the phase change position interval of the overlapping points, the phase change position interval of the non-overlapping points and the phase change position interval of the entire process according to the temperature distribution; Step 4: When the coil spinning is finished, the optimal process calculation module traverses and calculates the temperature changes of the overlap points and non-overlap points in the entire air cooling process according to the given air cooling process standard, and determines the air cooling process with the highest consistency between the overlap point phase change process and the non-overlap point phase change process according to the phase change position interval. The setting of the adjustment range is determined by the air cooling process; the phase change position interval of the entire phase change process is the combined interval of the phase change position interval of the overlap point and the phase change position interval of the non-overlap point; The judgment criterion for the consistency of the phase change process of the overlap point and the phase change process of the non-overlap point is: within a given air cooling process standard range, the higher the overlap rate of the phase change interval of the overlap point and the phase change interval of the non-overlap point or the narrower the position interval of the entire phase change process, the higher the consistency of the phase change process of the overlap point and the phase change process of the non-overlap point; Step 5: The air cooling process setting module combines the product tracking queue and the air cooling process with the highest consistency obtained in step 4 to realize dynamic setting of the air cooling process.

2. The post-rolling cooling control method based on the high-speed wire lap state according to claim 1 is characterized in that: The step 1 comprises: Step 1.1: The product position tracking module obtains the spinning start signal of the coil, establishes a product tracking queue on the air-cooled roller, adds the product information corresponding to the currently spinning coil to the head of the product tracking queue, and initializes the product information; Step 1.2: The product position tracking module obtains the unwinding signal of the coil located at the end of the product tracking queue, and removes the product information corresponding to the coil from the product tracking queue; Step 1.3: The product position tracking module obtains the periodic excitation signal, calculates and updates the positions of all coils. The calculation formula is as follows: Pos(i,N)=Pos(i,N-1)+V(k)×t1 Formula (1) Among them, Pos(i,N) is the position of the coil with coil number i in the Nth cycle of the excitation signal, the unit is m; Pos(i,N-1) is the position of the excitation signal of the coil with coil number i in the N-1th cycle, in m; k is the number of the roller control section, V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s; t1 is the time interval of the periodic excitation signal, in seconds.

3. The post-rolling cooling control method based on the high-speed wire lap state according to claim 1 or 2, characterized in that: The product information includes the following information: coil number, steel type, wire diameter, spinning circle diameter, spinning temperature, spinning speed, air cooling process standard, spinning time, current position, and initial position.

4. The post-rolling cooling control method based on the high-speed wire lap state according to claim 1 is characterized in that: The step 2 comprises: Step 2.1: The overlap state tracking module calculates the overlap number n of all coils on each roller control section. The total number of overlap points between the current coil and other coils is 4n. The calculation formula of n is: n=D / W formula (2) Wherein, D is the spinning circle diameter; W is the distance between adjacent coils, and its calculation formula is: W = 3.14159 × V (k) × D / V0 Formula (3) Where V0 is the spinning speed; V(k) is the roller speed of the roller control section numbered k at the N-1th cycle excitation signal, in m / s; Step 2.2: Define the running direction of the coil on the roller as the X-axis, define the direction perpendicular to the X-axis as the Y-axis, project the jth overlap point onto the Y-axis, the value range of j is [1, n], and calculate the overlap point P j The Y-axis coordinate H j , thus obtaining the position distribution of n overlapping points on the Y axis; The overlapping point P j The Y-axis coordinate H j The calculation formula is: H j =[(D / 2) 2 -(j×W / 2) 2 ] 1 / 2 Formula (4).

5. The post-rolling cooling control method based on the high-speed wire lap state according to claim 1 is characterized in that: The step 3 comprises: Step 3.1: Calculate the first surface heat transfer coefficient hr1 of the non-overlapping point. The calculation formula is: h r1 =1.25u 0.25 (G r ×P r ) 0.35 Formula (5) Among them, u is the cooling wind speed, the unit is m / s, and its calculation formula is: Where P is the power of the cooling equipment, which is determined by the characteristics of the air cooling equipment and the air cooling process standards; a0, a1, and a2 are regression coefficients, which are determined by the characteristics of the air-cooling equipment; δ is the proportion of the middle or side of the coil to the output air volume of the cooling fan: when calculating the cooling air speed in the middle of the coil, δ uses the proportion of the middle of the coil to the output air volume of the cooling fan; when calculating the cooling air speed at the side of the coil, δ uses the proportion of the side of the coil to the output air volume of the cooling fan; G r is the Grashof number; P r is the Prandtl number at room temperature; Step 3.2: Calculate the second surface heat transfer coefficient h of the overlap point r2 , the calculation formula is: Wherein, κ is the correction coefficient. When the overlap number n changes, κ>1, and when the overlap number n remains unchanged, κ=1; is the heat transfer coefficient of the second overlap point at different overlap densities h r2 The impact of R is the wire radius, in m; λ is the thermal conductivity of the cooling medium, i.e. air, in W / (mK); Re f is the Reynolds number corresponding to the average temperature of the ambient temperature and the surface temperature of the coil overlap point; Pr f The corresponding temperature is the average of the ambient temperature and the surface temperature of the coil junction. r value; Pr s The corresponding temperature is the Prandtl number P of the surface temperature of the coil joint. r value; Step 3.3: Calculate the coil temperature. The calculation model is: Where T is temperature, t is time, r is the calculation radius, and the value range of r is [0, R]; a is the thermal conductivity of the coil, in W / (mK); c p is the specific heat of the coil, in J / kg.K; ρ is the density of the coil, in kg / m 3 ; g(T) is the phase transition heat of austenite to ferrite and pearlite, and its calculation formula is: Where H(T) is the phase change heat, in J·kg -1 ; X is the phase change variable, and its calculation formula is: X = 1-exp(-bt2 m ) Formula (10) Where, T1 is the current temperature, t2 is the transition time, m = 0.99; △X is the phase change variable increment of the phase change variable X within the time △t; The initial conditions of formula (8) are: T = 0, 0 ≤ r ≤ R T = T0(r); Among them, T0 is the spinning temperature of the coil; The boundary conditions of formula (8) are: Among them, T air is the ambient temperature; h r is the first surface heat transfer coefficient h r1 Or the second surface heat transfer coefficient h r2 ; Step 3.4: The product position tracking module obtains the wire-spinning end signal and the wire-spinning performance, and the optimal process calculation module traverses and calculates the temperature distribution of the wire from wire-spinning to unwinding under the air cooling process standard; Step 3.5: According to the temperature distribution of the wire, determine the start and end time of the phase change at the overlap point and the phase change at the non-overlap point; Step 3.6: Calculate the phase change position interval of the overlapping points, the phase change position interval of the non-overlapping points and the phase change position interval of the entire phase change process. The phase change position interval of the entire phase change process is the combined interval of the phase change position interval of the overlapping points and the phase change position interval of the non-overlapping points.

6. The post-rolling cooling control method based on the high-speed wire lap state according to claim 5 is characterized in that: In step 3.5, the criterion for determining the start time of the phase change process is: Among them, △t i The coil temperature is T i The calculation time step is ; τ i The coil temperature is T i The phase transition incubation time; f(ε) is the function of the accumulated strain in the phase change material; When formula (11) is satisfied, the phase change process is considered to have started; when the phase change amount X>0.99, the phase change is considered to have ended.

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