CN109013717B - A Calculation Method of Core Temperature of Hot Continuous Rolling Intermediate Billet - Google Patents

Abstract

The invention provides a method for calculating the core temperature of a hot continuous rolling intermediate slab, and relates to the technical field of steel rolling automatic control. This method calculates the average temperature of the rolled piece based on the actual measurement of the rolling force speed, width and thickness of the final rolling pass in the rough rolling area, and calculates the temperature drop loss of the rolled piece on the transport roller table through the calculation of the air-cooled temperature drop, and obtains the rolling piece The average temperature of the rolled piece, combined with the surface temperature of the rolled piece at any position in the middle roller table, can be calculated to obtain the core temperature of the rolled piece. The method of the present invention has high safety and high calculation accuracy, can be successfully applied to the calculation process of the core temperature of the intermediate billet in the hot continuous rolling mill, solves the problem that the core temperature of the intermediate billet cannot be directly measured online in the actual process, and saves production investment costs. At the same time, the calculation accuracy of the temperature is guaranteed, which provides a good foundation for the online precise control of the thickness of the finished product.

Description

A Calculation Method of Core Temperature of Hot Continuous Rolling Intermediate Billet

technical field

The invention relates to the technical field of steel rolling automatic control, in particular to a method for calculating the core temperature of a hot continuous rolling intermediate slab.

Background technique

In the process of hot continuous rolling, the core temperature of the intermediate billet is the basis for accurate calculation of the rolling force in the finishing rolling area. The thermometer installed on the rolling line can only measure the surface temperature of the rolled piece, but cannot measure the core temperature of the rolled piece; since the rolled piece runs at a certain speed on the intermediate roller table, it is also impossible to measure the real-time heart temperature by embedding a thermocouple. internal temperature measurement.

During the heating process of the slab in the heating furnace, it is heated to the target discharge temperature according to a certain temperature rise curve, and the slabs loaded into the heating furnace are of different types such as hot charging slabs and cold slabs, and there are also cases where the two kinds of slabs are mixed. , the temperature of the two kinds of slabs entering the furnace is inconsistent, resulting in that when the slabs come out of the furnace, the surface temperature of the slabs is basically the same, but there is a big difference in the temperature of the core. In the actual control process, the surface temperature is generally used to calculate the core temperature. Temperature, when the above-mentioned cold and hot slabs are mixed, the calculation accuracy of the core temperature cannot be guaranteed, which has a great impact on the actual control effect.

The calculation of the core temperature mentioned in the document "Numerical Simulation of the Temperature Field in the Rough Rolling Area of Hot-Rolled Strip Steel" is carried out by the method of finite element analysis. The boundary conditions used in this method are based on experience and assumptions, and the calculation time is long , not for online use.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for calculating the temperature of the core of the hot continuous rolling billet in view of the shortcomings of the above-mentioned prior art, which has high safety and high calculation accuracy, and can be successfully applied to the temperature of the core of the hot continuous rolling mill. The calculation process solves the problem that the core temperature of the intermediate billet cannot be directly measured online in the actual process. While saving production investment costs, it ensures the calculation accuracy of the temperature and provides a good foundation for the online precise control of the thickness of the finished product.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A method for calculating the core temperature of a hot continuous rolling intermediate slab, comprising the following steps:

Step 1: The slab is out of the furnace, and the PDI data of the slab is obtained;

Step 2: According to the PDI data, the calculation of the second-level model of rough rolling is triggered, and the slab is rolled in an odd number of passes in accordance with the rough rolling regulations;

Step 3: The last pass starts, the rolled piece reaches the instrument group before the roughing mill, and the measured average thickness, width and surface temperature of the rolled piece are obtained; the measured average thickness, width and surface temperature of the rolled piece are The average temperature is the average value of sampling points that meet the effective range of thickness, width and surface temperature of this pass; the specific method is as follows:

Step 3.1: If the value of the thickness sampling point collected by the thickness gauge exceeds the specified effective range of thickness for this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 3.2;

Step 3.2: Perform mean value processing on the obtained effective thickness sampling value, and calculate the average value h ₀ of the measured thickness according to the following formula:

In the formula, h _{0, i} is the thickness value of the ith effective thickness sampling point, i=1, 2, 3,..., N;

Step 3.3: If the value of the width sampling point collected by the thermometer exceeds the specified effective range of the width of this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 3.4;

Step 3.4: Perform mean value processing on the obtained sampling values of the effective width, and calculate the average value w ₀ of the measured width according to the following formula:

In the formula, w _{0, j} is the width value of the jth effective width sampling point, j=1, 2, 3,..., N;

Step 3.5: If the value of the surface temperature sampling point collected by the thermometer exceeds the specified valid range of temperature for this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 3.6;

Step 3.6: Perform mean value processing on the obtained effective surface temperature sampling values, and calculate the average value T ₀ of the measured surface temperature according to the following formula:

In the formula, T _{0, k} is the temperature value of the kth effective surface temperature sampling point, k=1, 2, 3,..., N;

Step 4: The rolled piece reaches the rolling deformation zone, records the moment when the rolled piece reaches the rolling deformation zone, calculates the time for the rolled piece to reach the rolling deformation zone from the thermometer, and obtains the average value of the measured rolling force in the rolling deformation zone, The average value of the roll speed; the average value of the measured rolling force and the average value of the roll speed are respectively the average values of the sampling points that meet the effective range of the rolling force and roll speed of this pass; the specific methods are as follows:

Step 4.1: The moment when the head of the rolled piece reaches the thermometer is t _roll ;

Step 4.2: If the value of the rolling force sampling point collected by the pressure sensor exceeds the specified effective range of the rolling force for this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 4.3;

Step 4.3: Perform mean value processing on the obtained effective rolling force sampling value, and calculate the average value P0 of the measured rolling force according to the following formula:

In the formula, P _{0, l} is the rolling force value of the lth sampling point of effective rough rolling exit temperature, l = 1, 2, 3, ..., N;

Step 4.4: If the value of the roll speed sampling point collected by the speed sensor exceeds the specified effective range of the speed of this pass, then reject it, and when the count of valid sampling points reaches the specified number N, proceed to step 4.5;

Step 4.5: Perform mean value processing on the obtained effective roll speed sampling value, and calculate the measured roll speed average v according to the following formula:

In the formula, v _m is the temperature value of the mth effective rough rolling exit temperature sampling point, m=1, 2, 3,..., N;

Step 5: The instrument group after the rolled piece reaches the rough rolling mill, obtain the average value of the measured thickness, width and surface temperature of the rolled piece; record the time from the head of the rolled piece to the exit thermometer, and calculate the time from the deformation zone to the temperature of the rolled piece. The time of the thermometer; the average value of the measured thickness of the rolled piece, the average value of the width and the average value of the surface temperature are respectively the average values of the sampling points that meet the effective range of the thickness, width and surface temperature of this pass; the specific methods are as follows:

Step 5.1: If the value of the thickness sampling point collected by the thickness gauge exceeds the specified effective range of thickness for this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 5.2;

Step 5.2: Perform mean value processing on the obtained effective thickness sampling value, and calculate the average value h1 of the measured thickness according to the following formula:

In the formula, h _{1, n} is the thickness value of the nth effective thickness sampling point, n=1, 2, 3,..., N;

Step 5.3: If the value of the width sampling point collected by the thermometer exceeds the specified effective temperature range of this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 5.4;

Step 5.4: Perform mean value processing on the obtained sampling values of the effective width, and calculate the average value w ₁ of the measured width according to the following formula:

In the formula, w _{1, e} is the width value of the eth effective width sampling point, e=1, 2, 3,..., N;

Step 5.5: If the value of the surface temperature sampling point collected by the thermometer exceeds the specified valid temperature range for this pass, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 5.6;

Step 5.6: Perform mean value processing on the obtained effective surface temperature sampling values, and calculate the average value T ₁ of the measured surface temperature according to the following formula:

In the formula, T _{1, f} is the temperature value of the fth effective surface temperature sampling point, f=1, 2, 3,..., N;

Step 5.7: Record the time t ₁ from the head of the rolled piece to the exit thermometer, and calculate the time from the deformation zone to the thermometer: τ ₁ =t ₁ -t _roll ;

Step 6: Calculate the average temperature of the rolled piece during rolling deformation, and calculate the core temperature of the rolled piece at the outlet thermometer. The specific calculation method is:

Step 6.1: Calculate the deformation temperature of the rolled piece at the deformation zone according to the relationship between the rolling force calculation model and the temperature;

The calculation formula of rolling force P is as follows:

P＝1.15K _m l _c Q _P B/1000

In the formula, B is the width of the rolled piece, mm; K _m is the deformation resistance, MPa, which is a function of the deformation temperature, as shown in the following formula:

T is the average temperature of the rolled piece in the deformation zone, K; l _c is the contact arc length after considering flattening, mm, R' is the flattening radius, mm, R is the radius of the roll, mm; Δh is the reduction, mm, Δh=h ₀ -h ₁ ; Q _P is the stress state influence coefficient, h _m is the average thickness of the rolled piece, mm, is the degree of deformation, %, is the deformation rate, s ^-1 ,

Step 6.2: Calculate the air-cooled temperature drop of the rolled piece from the deformation zone to the outlet thermometer;

According to the calculation in step 6.1, the average temperature of the rolled piece in the deformation zone is recorded as T _roll . According to the calculation in step 5.7, the time from the deformation zone to the rough rolling exit thermometer is τ ₁ , and the average temperature at the exit thermometer is temperature It is calculated by the following formula:

In the formula, ε is the heat radiation rate, ε=0.7; σ is the Stefan-Boltzmann constant, σ=5.69×10 ^-8 W/(m ² .K ⁴ ); c is the specific heat of the rolled piece, J/kg K; γ is the density of the rolled piece, kg/m ³ ;

Step 6.3: Calculate the core temperature T _{core of the rolled piece according to the average temperature of the rolled piece at the outlet thermometer, 1} :

Step 7: When the rolled piece reaches the finish-rolling entrance thermometer, obtain the average value of the measured surface temperature of the rolled piece; record the time when the head of the rolled piece reaches the finish-rolling entrance thermometer, and calculate the time when the rolled piece passes from the rough-rolling exit thermometer to the finish-rolling temperature gauge. The time of the entrance thermometer; the average value of the surface temperature of the measured rolled piece is respectively the average temperature of the sampling points that meet the effective range of the surface temperature; the specific method is:

Step 7.1: If the value of the thickness sampling point collected by the thermometer exceeds the specified effective range of temperature, then remove it, and when the count of valid sampling points reaches the specified number N, proceed to step 7.2;

Step 7.2: Perform mean value processing on the obtained effective temperature sampling values, and calculate the average value T2 of the measured surface temperature according to the following formula:

In the formula, T2 _{, q} is the temperature value of the qth effective temperature sampling point, q=1, 2, 3,..., N;

Step 7.3: Record the time t ₂ when the head of the rolled piece reaches the finish-rolling entrance thermometer, and calculate the time for the rolled piece to pass from the rough-rolling exit thermometer to the finish-rolling entrance thermometer: τ ₂ =t ₂ -t ₁ ;

Step 8: Calculate the average surface temperature of the rolled piece at the finish rolling entrance thermometer, and calculate the core temperature of the intermediate billet. The specific calculation method is:

Step 8.1: Calculate the air-cooled temperature drop of the rolled piece from the rough rolling exit thermometer to the finish rolling entrance;

Calculate the average temperature of the rolled piece in the deformation zone according to step 6.2 Calculated in step 7.3, the time τ ₂ for the rolled piece from the rough rolling exit thermometer to the finish rolling entrance thermometer, and the average temperature at the finish rolling entrance thermometer It is calculated by the following formula:

Step 8.2: According to the average temperature of the rolled piece at the entrance thermometer of the finish rolling The surface temperature T ₂ of the rolled piece at the entrance thermometer of the finish rolling is calculated as the core temperature T _{core of the rolled piece at the entrance thermometer of the finish rolling, 2} is:

The beneficial effects produced by adopting the above-mentioned technical scheme are: a method for calculating the core temperature of the hot continuous rolling intermediate slab provided by the present invention is calculated according to the actual measurement of the rolling force speed, width and thickness of the final rolling pass in the rough rolling area. The average temperature of the rolled piece is obtained, and the temperature drop loss of the rolled piece on the conveying roller table is obtained by calculating the temperature drop of the rolled piece, and the average temperature of the rolled piece is obtained, and further combined with the surface temperature of the rolled piece at any position on the intermediate roller table, it can be calculated Get the core temperature of the rolled piece. The invention has high safety and high calculation accuracy, can be successfully applied to the calculation process of the core temperature of the intermediate billet in the hot continuous rolling mill, solves the problem that the core temperature of the intermediate billet cannot be directly measured online in the actual process, and saves production investment costs. Guaranteed temperature calculation accuracy. The present invention has nothing to do with the installation position of the middle roller table temperature measuring instrument. It only needs to use the online measurement to obtain the time when the rolled piece runs to the temperature measuring instrument to calculate the core temperature of the rolled piece, which can effectively improve the temperature forecast of the intermediate billet The precision provides a good foundation for the online precise control of the thickness of the finished product.

Description of drawings

Fig. 1 is the layout diagram of main equipment and instruments in the hot continuous rolling rough rolling area provided by the embodiment of the present invention;

Fig. 2 is a schematic diagram of the final pass rolling in the hot continuous rolling rough rolling area provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of a parabolic distribution of internal temperature of a rolled piece provided by an embodiment of the present invention;

Fig. 4 is a flow chart for calculating the temperature of the core part of the intermediate billet provided by the embodiment of the present invention.

In the figure, 1. Heating furnace; 2. Thickness gauge before roughing mill; 3. First width gauge; 4. First temperature gauge; 5. Roughing unit; 6. Speed sensor; 7. Pressure sensor; 8 1. Thickness gauge after rough rolling mill; 9. Second width gauge; 10. Second thermometer; 11. Thermometer before finishing mill; 12. Slab; 13. Intermediate billet; 14. Finishing unit.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

This embodiment adopts a typical hot continuous rolling production line roughing unit, and the roughing unit adopts the arrangement form of "vertical roll + flat roll" as shown in Figure 1, the vertical roll is in front and the flat roll is behind; the slab is heated in the heating furnace 1 To the furnace temperature, a thickness gauge 2, a width gauge 3 and a temperature gauge 4 are arranged in front of the rough rolling unit 5, and a thickness gauge 8, a width gauge 9 and a temperature gauge 10 are arranged behind the machine. A speed sensor 6 and a pressure sensor 7 are installed on the rolling mill; the intermediate billet 13 is obtained through the rough rolling process with an odd number of passes in total, passes through the entrance thermometer 11 of the finishing rolling area, and finally reaches the finishing rolling unit 14.

In the production process of the hot continuous rolling rough rolling area, the thickness gauge measures the thickness of the rolled piece, the width gauge measures the width of the rolled piece, the thermometer measures the surface temperature of the rolled piece, and the rolling mill pressure sensor measures the rolling force and speed sensor during the deformation process of the rolled piece Measure the running speed of the roll. Thickness gauge 2 before rough rolling mill, width gauge 3, temperature gauge 4, speed sensor 6, pressure sensor 7, thickness gauge 8 after rough rolling mill, width gauge 9, temperature gauge 10 and temperature gauge before finishing mill The measurement signals generated in 11 are transmitted from the basic automation level to the process automation level, and the entire intermediate billet core temperature calculation process is completed at the process automation level. The communication period of the basic automation level and the process automation level is 100ms, that is, a sampling point is obtained every 100ms; the rolled piece is rolled back and forth in the rough rolling area, and the last rolling pass is an odd number of passes. The time from the rolled piece to the head of the rolled piece to the deformation zone, the rough rolling exit thermometer and the finish rolling entrance thermometer can be recorded by the process automation level, as shown in Figure 2.

A method for calculating the core temperature of a hot continuous rolling intermediate slab, as shown in FIG. 4 , and the specific process is as follows.

Step 1: The slab is out of the furnace, and the PDI data of the slab is obtained.

The PDI data mainly include slab size, intermediate billet size, finished product size, steel grade name and chemical composition. The PDI data in this embodiment are shown in Table 1. When the slab comes out of the furnace, send the PDI data to the rough rolling process control system.

Table 1 PDI data

serial number content value unit 1 steel type Q235B 2 Slab size 7000×1000×180 mm×mm×mm 3 Intermediate billet size 1050×35.0 mm×mm 4 product size 1050×3.50 mm×mm 5 chemical element carbon 0.16 % 6 chemical element silicon 0.19 % 7 chemical element manganese 0.30 % 8 chemical element chromium 0.10 % 9 chemical element nickel 0.12 % 10 chemical element phosphorus 0.03 % 11 chemical element sulfur 0.03 %

Step 2: According to the PDI data, trigger the calculation of the rough rolling setting model, and the slab performs the rolling process with a total number of odd passes according to the rough rolling rolling procedure;

Step 3: The last pass starts, the rolled piece reaches the instrument group before the roughing mill, and the measured average thickness, width and surface temperature of the rolled piece are obtained; the measured average thickness, width and surface temperature of the rolled piece are The average temperature is the average value of sampling points that meet the valid range of thickness, width and surface temperature of this pass.

Step 3.1: If the value of the thickness sampling point collected by the thickness gauge exceeds the specified valid range of the thickness of this pass, then reject it, and when the count of valid sampling points reaches the specified number N, proceed to step 3.2; in this embodiment, N is taken as 20;

Step 3.2: Perform mean value processing on the obtained effective thickness sampling value, and calculate the average value of the measured thickness;

Measured average thickness h ₀ :

In the formula, h _{0, i} is the thickness value of the ith effective thickness sampling point, i=1, 2, 3,..., 20;

Step 3.3: If the value of the width sampling point collected by the thermometer exceeds the specified effective range of the width of this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 3.4;

Step 3.4: Perform mean value processing on the obtained effective width sampling value, and calculate the average value of the measured width;

Measured average width w ₀ :

In the formula, w _{0, j} is the width value of the jth effective width sampling point, j=1, 2, 3,..., 20;

Step 3.5: If the value of the surface temperature sampling point collected by the thermometer exceeds the specified valid temperature range for this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 3.6;

Step 3.6: Perform mean value processing on the obtained effective surface temperature sampling value, and calculate the average value of the measured surface temperature;

Measured average surface temperature T ₀ :

In the formula, T _{0, k} is the temperature value of the kth effective surface temperature sampling point, k=1, 2, 3,..., 20;

Step 4: The rolled piece reaches the rolling deformation zone, records the moment when the rolled piece reaches the rolling deformation zone, calculates the time for the rolled piece to reach the rolling deformation zone from the thermometer, and obtains the average value of the measured rolling force in the rolling deformation zone, The average value of the roll speed; the average value of the measured rolling force and the average value of the roll speed are respectively the average values of the sampling points that meet the effective range of the rolling force and roll speed of this pass.

Step 4.1: The moment when the head of the rolled piece reaches the thermometer is t _roll ;

Step 4.2: If the value of the rolling force sampling point collected by the pressure sensor exceeds the specified effective range of the rolling force for this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 4.3;

Step 4.3: Perform mean value processing on the obtained sampling values of the effective rolling force, and calculate the average value of the measured rolling force;

The average value of the measured rolling force P ₀ :

In the formula, P _{0, l} is the rolling force value of the lth sampling point of effective rough rolling outlet temperature, l=1, 2, 3,..., 20;

Step 4.4: If the value of the roll speed sampling point collected by the speed sensor exceeds the specified effective range of speed for this pass, then reject it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 4.5;

Step 4.5: Perform mean value processing on the obtained effective roll speed sampling value, and calculate the average value of the measured roll speed;

The average value of measured roll speed v:

In the formula, v _m is the temperature value of the mth sampling point of effective rough rolling exit temperature, m=1, 2, 3,..., 20;

Step 5: The instrument group after the rolled piece passes through the roughing mill, obtains the average value of the measured thickness, width, and surface temperature of the rolled piece; The time of the thermometer; the measured average thickness, average width and surface temperature of the rolled piece are the average values of the sampling points that meet the effective ranges of the thickness, width and surface temperature of the pass.

Step 5.1: If the value of the thickness sampling point collected by the thickness gauge exceeds the specified effective range of the thickness of this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 5.2;

Step 5.2: Perform mean value processing on the obtained effective thickness sampling value, and calculate the average value of the measured thickness;

Measured average thickness h ₁ :

In the formula, h _{1, n} is the thickness value of the nth effective thickness sampling point, n=1, 2, 3,..., 20;

Step 5.3: If the value of the width sampling point collected by the thermometer exceeds the specified effective temperature range of this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 5.4;

Step 5.4: Perform mean value processing on the obtained effective width sampling value, and calculate the average value of the measured width;

Measured average width w ₁ :

In the formula, w _{1, e} is the width value of the eth effective width sampling point, e=1, 2, 3,..., 20;

Step 5.5: If the value of the surface temperature sampling point collected by the thermometer exceeds the specified valid temperature range for this pass, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 5.6;

Step 5.6: Perform mean value processing on the obtained effective surface temperature sampling value, and calculate the average value of the measured surface temperature;

Measured average surface temperature T ₁ :

In the formula, T _{1, f} is the temperature value of the fth effective surface temperature sampling point, f=1, 2, 3,..., 20;

Step 5.7: Record the time t ₁ from the head of the rolled piece to the exit thermometer, and calculate the time from the deformation zone to the thermometer as follows:

t ₁ -t _rol1 = 2.2s

Step 6: Calculate the average temperature of the rolled piece during rolling deformation, and calculate the core temperature of the rolled piece at the outlet thermometer;

Step 6.1: Calculate the deformation temperature of the rolled piece at the deformation zone according to the relationship between the rolling force calculation model and the temperature; wherein, the deformation resistance K _m is a function of the deformation temperature.

The calculation formula of rolling force P is as follows:

P＝1.15K _m l _c Q _P B/1000

In the formula: B- width of rolled piece, mm;

K _m - deformation resistance, MPa:

T-average temperature of the rolled piece in the deformation zone, K;

l _c - contact arc length after considering flattening, mm;

R'- flattening radius, mm;

R-roll radius, mm;

Δh-reduction amount, mm;

Δh=h ₀ -h ₁ ;

Q _P - stress state influence factor:

h _m - the average thickness of the rolled piece, mm;

r-deformation degree, %;

- deformation rate, s ^-1 ;

Through the solution, the average temperature of the deformation zone is 1158.15K. The data used for the calculation of the final pass of rough rolling is shown in Table 2, and the deformation parameters of the final pass of rough rolling are shown in Table 3.

Table 2 Data for calculating the final pass of rough rolling

parameter name unit value Inlet thickness mm 51.2 Exit thickness mm 35.1 entrance width mm 1250.1 Exit width mm 1251.2 Inlet temperature K 1370.25 output temperature K 1345.55 Rolling force kN 17094.04 Rolling speed m/s 3.3 Roll radius mm 450

Table 3 Deformation parameters of final pass of rough rolling

Step 6.2: Calculate the air-cooled temperature drop of the rolled piece from the deformation zone to the outlet thermometer;

During the running process of the rolled piece, the temperature of the rolled piece is high during the rough rolling process, and the heat loss by radiation far exceeds the natural convection loss and the contact heat loss with the roller table. Therefore, only the influence of heat radiation is considered in the temperature drop calculation process.

According to the calculation in step 6.1, the average temperature of the rolled piece in the deformation zone is 1358.35K, which is recorded as T _roll ; according to the calculation in step 5.7, the time from the deformation zone to the rough rolling exit thermometer is τ ₁ =t ₁ -t _roll = 2.2s:

The average temperature at the outlet thermometer It is calculated by the following formula:

In the formula: ε is the heat radiation rate, ε=0.7; σ is the Stefan-Boltzmann constant, σ=5.69×10 ^-8 W/(m ² ·K ⁴ ); c is the specific heat of the rolled piece, J/kg K; γ is the density of the rolled piece, kg/m ³ ;

Step 6.3: Calculate the core temperature of the rolled piece according to the average temperature of the rolled piece at the outlet thermometer;

Inside the strip, the temperature is distributed in a parabola from the center to the surface, as shown in Figure 3. The calculation formula of heart temperature T _core is:

Therefore, the average temperature The surface temperature T _m = T ₁ = 1345.55K, the core temperature T _{core at the rough rolling exit thermometer, 1} is:

Step 7: When the rolled piece reaches the finish-rolling entrance thermometer, obtain the average value of the measured surface temperature of the rolled piece; record the time when the head of the rolled piece reaches the finish-rolling entrance thermometer, and calculate the time when the rolled piece passes from the rough-rolling exit thermometer to the finish-rolling temperature gauge. The time of the entrance thermometer; the average value of the measured surface temperature of the rolled piece is the average temperature of the sampling points that meet the effective range of the surface temperature.

Step 7.1: If the value of the thickness sampling point collected by the thermometer exceeds the specified effective range of temperature, then remove it, and when the count of valid sampling points reaches the specified number (take 20 here), proceed to step 7.2;

Step 7.2: Perform mean value processing on the obtained effective temperature sampling values, and calculate the average value of the measured surface temperature;

Measured average surface temperature T ₂ :

In the formula, T2 _,q is the temperature value of the qth effective temperature sampling point, q=1, 2, 3,..., 20;

Step 7.3: Record the time t ₂ when the head of the rolled piece reaches the finish-rolling entrance thermometer, and calculate the time for the rolled piece to pass from the rough-rolling exit thermometer to the finish-rolling entrance thermometer:

τ ₂ =t ₂ -t ₁ =15.3s

Step 8: Calculate the average surface temperature of the rolled piece at the finish rolling entrance thermometer, and calculate the core temperature of the intermediate billet;

Step 8.1: Calculate the air-cooled temperature drop of the rolled piece from the rough rolling exit thermometer to the finish rolling entrance;

According to the calculation of step 6.2, the average temperature of the rolled piece in the deformation zone is According to the calculation in step 7.3, the time for the rolled piece to pass from the rough rolling exit thermometer to the finish rolling entrance thermometer is τ ₂ =t ₂ -t ₁ =15.3s:

The average temperature at the finish-rolling entrance thermometer It is calculated by the following formula:

Step 8.2: Repeat step 6.3 to calculate the heart temperature;

The average temperature of the rolled piece at the entrance thermometer of the finish rolling Surface temperature T _m = T ₂ = 1301.75K at the finish-rolling entrance thermometer, and the core temperature T _{core at the finish-rolling entrance thermometer, 2} is:

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope defined by the claims of the present invention.

Claims (4)

1. base center portion temperature computation method among a kind of hot continuous rolling, it is characterised in that: the following steps are included:

Step 1: slab is come out of the stove, and obtains slab PDI data；

Step 2: being calculated according to PDI data-triggered roughing second-level model, it is surprise that slab, which carries out total passage according to roughing rolling procedure, The operation of rolling of several time；

Step 3: most end passage starts, and rolled piece reaches the instrument group before roughing mill, and it is flat to obtain actual measurement rolled piece thickness average value, width Mean value and surface temperature average value；The actual measurement rolled piece thickness average value, width average value and surface temperature average value are respectively Meet the sampled point average value of this passage thickness, width and surface temperature effective range；

Step 4: rolled piece reach contact in rolling, record rolled piece reach contact in rolling at the time of, calculate rolled piece by temperature measurer to The time of contact in rolling obtains actual measurement roll-force average value, the speed of rolls average value of contact in rolling；The actual measurement rolling Power average value, speed of rolls average value respectively meet this passes power and the sampled point of speed of rolls effective range is average Value；

Step 5: rolled piece reaches the instrument group after roughing mill, obtains actual measurement rolled piece thickness average value, width average value and surface temperature Spend average value；Workpiece front end is recorded at the time of exporting temperature measurer, calculates rolled piece by the time of deformed area to temperature measurer；The reality Surveying rolled piece thickness average value, width average value and surface temperature average value is respectively to meet this passage thickness, width and surface temperature Spend the sampled point average value of effective range；

Step 6: calculating rolled piece mean temperature when rolling deformation, calculate center portion temperature of the rolled piece at outlet temperature measurer；Specifically Calculation method are as follows:

Step 6.1: according to the relationship between tube rolling simulation model and temperature, calculating rolled piece in the deformation temperature of deformed area；

The calculation formula of roll-force P is as follows:

P=1.15K_ml_cQ_PB/1000

In formula, B is rolled piece width, mm；K_mFor resistance of deformation, MPa is the function of deformation temperature, is shown below:

T is deformed area rolled piece mean temperature, K；l_cContact arc length after being flattened for consideration, mm,R ' is to flatten half Diameter, mm,R is roller radius, mm；Δ h is drafts, mm, Δ h=h₀-h₁, h₀For step 3 The actual measurement rolled piece thickness average value of middle acquisition, h₁For the actual measurement rolled piece thickness average value obtained in step 5；Q_PFor stress state shadow Coefficient is rung,h_mFor rolled piece average thickness, mm,R is deformation extent, %, For rate of deformation, s^-1,V is in step 4 The speed of rolls average value of acquisition；

Step 6.2: calculating air-cooled temperature drop of the rolled piece from deformed area to from outlet temperature measurer；

Deformation temperature of the rolled piece in deformed area is calculated according to step 6.1 and is denoted as T_roll, reach the average temperature at outlet temperature measurer DegreeIt is calculated by following formula:

In formula, ε is thermal emissivity rate, ε=0.7；σ is Stefan-Boltzmann constant, σ=5.69 × 10^-8W/(m²·K⁴)；C is Rolled piece specific heat, J/kgK；γ is rolled piece density, kg/m³, τ₁For the rolled piece that is calculated in step 5 by deformed area to temperature measurer when Between；

Step 6.3: rolled piece center portion temperature T is calculated according to the rolled piece mean temperature at outlet temperature measurer_{Core, 1}:

Wherein, T₁The actual measurement surface temperature average value calculated for step 5；

Step 7: rolled piece reaches finish rolling entrance temperature measurer, obtains actual measurement rolled piece surface temperature average value；Workpiece front end is recorded to reach At the time of finish rolling entrance temperature measurer, rolled piece is calculated by the time of roughing outlet temperature measurer to finish rolling entrance temperature measurer；The actual measurement Rolled piece surface temperature average value is respectively the temperature averages for meeting the sampled point of surface temperature effective range；Method particularly includes:

Step 7.1: if the numerical value of the collected thickness sampled point of temperature measurer exceeds defined temperature effective range, reject, when When effective sampling points counting reaches defined amount N, step 7.2 is carried out；

Step 7.2: average value processing being carried out to obtained effective temperature sampled value, actual measurement surface temperature average value T is calculated as follows₂:

In formula, T_{2, q}For the temperature value of q-th of effective temperature sampled point, q=1,2,3 ..., N；

Step 7.3: t at the time of record workpiece front end reaches finish rolling entrance temperature measurer₂, rolled piece is calculated by roughing and exports thermometric Time of the instrument to finish rolling entrance temperature measurer are as follows: τ₂=t₂-t₁, t₁It is workpiece front end at the time of exporting temperature measurer；

Step 8: calculating mean temperature of the rolled piece at finish rolling entrance temperature measurer, the center portion temperature of intermediate base is calculated；Specifically Calculation method are as follows:

Step 8.1: calculating air-cooled temperature drop of the rolled piece from roughing outlet temperature measurer to finish rolling entrance；

Rolled piece is calculated in the mean temperature of deformed area according to step 6.2Rolled piece is calculated in step 7.3 to be gone out by roughing Time τ of the mouth temperature measurer to finish rolling entrance temperature measurer₂, reach the mean temperature at finish rolling entrance temperature measurerIt is calculated by following formula It arrives:

Step 8.2: according to rolled piece mean temperature at finish rolling entrance temperature measurerRolled piece surface temperature is flat at finish rolling entrance temperature measurer Mean value T₂, calculate the rolled piece center portion temperature T at finish rolling entrance temperature measurer_{Core, 2}Are as follows:

2. according to base center portion temperature computation method among hot continuous rolling described in claim l, it is characterised in that: the step 3 The specific method is as follows:

Step 3.1: if the numerical value of the collected thickness sampled point of calibrator exceeds defined this passage thickness effective range, picking It removes, when effective sampling points counting reaches defined amount N, carries out step 3.2；

Step 3.2: average value processing being carried out to obtained effective thickness sampled value, actual measurement thickness average value h is calculated as follows₀:

In formula, h_{0, i}For the thickness value of i-th of effective thickness sampled point, i=l, 2,3 ..., N；

Step 3.3: if the numerical value of the collected width sampled point of temperature measurer exceeds defined this passage width effective range, picking It removes, when effective sampling points counting reaches defined amount N, carries out step 3.4；

Step 3.4: average value processing being carried out to obtained effective width sampled value, actual measurement width average value w is calculated as follows₀:

In formula, w_{0, j}For the width value of j-th of effective width sampled point, j=1,2,3 ..., N；

Step 3.5: if the numerical value of the collected surface temperature sampled point of temperature measurer exceeds defined this passage temperature effective range, It then rejects, when effective sampling points counting reaches defined amount N, carries out step 3.6；

Step 3.6: average value processing being carried out to obtained active surface temperature sampling value, it is average that actual measurement surface temperature is calculated as follows Value T₀:

In formula, T_{0, k}For the temperature value of k-th of active surface temperature sampling point, k=l, 2,3 ..., N.

3. base center portion temperature computation method among hot continuous rolling according to claim 2, it is characterised in that: the step 4 The specific method is as follows:

Step 4.1: rolled piece is t at the time of reaching contact in rolling_roll；

Step 4.2: if the numerical value of the collected roll-force sampled point of pressure sensor is effective beyond defined this passes power Range is then rejected, and when effective sampling points counting reaches defined amount N, carries out step 4.3；

Step 4.3: average value processing is carried out to obtained effective roll-force sampled value, actual measurement roll-force average value P is calculated as follows:

In formula, P_{0, l}For the rolling force value of first of effective roughing outlet temperature sampled point, l=l, 2,3 ..., N；

Step 4.4: if the numerical value of the collected speed of rolls sampled point of velocity sensor is effective beyond this defined pass speed Range is then rejected, and when effective sampling points counting reaches defined amount N, carries out step 4.5；

Step 4.5: average value processing being carried out to obtained effective speed of rolls sampled value, it is average that the actual measurement speed of rolls is calculated as follows Value v:

In formula, v_mFor the velocity amplitude of m-th of effective roughing muzzle velocity sampled point, m=l, 2,3 ..., N.

4. base center portion temperature computation method among hot continuous rolling according to claim 3, it is characterised in that: the step 5 The specific method is as follows:

Step 5.1: if the numerical value of the collected thickness sampled point of calibrator exceeds defined this passage thickness effective range, picking It removes, when effective sampling points counting reaches defined amount N, carries out step 5.2；

Step 5.2: average value processing is carried out to obtained effective thickness sampled value, actual measurement thickness average value h1 is calculated as follows:

In formula, h_{1, n}For the thickness value of n-th of effective thickness sampled point, n=l, 2,3 ..., N；

Step 5.3: if the numerical value of the collected width sampled point of temperature measurer exceeds defined this passage temperature effective range, picking It removes, when effective sampling points counting reaches defined amount N, carries out step 5.4；

Step 5.4: average value processing being carried out to obtained effective width sampled value, actual measurement width average value w is calculated as follows₁:

In formula, w_{1, e}For the width value of e-th of effective width sampled point, e=1,2,3 ..., N；

Step 5.5: if the numerical value of the collected surface temperature sampled point of temperature measurer exceeds defined this passage temperature effective range, It then rejects, when effective sampling points counting reaches defined amount N, carries out step 5.6；

Step 5.6: average value processing being carried out to obtained active surface temperature sampling value, it is average that actual measurement surface temperature is calculated as follows Value T₁:

In formula, T_{1, f}For the temperature value of f-th of active surface temperature sampling point, f=1,2,3 ..., N；

Step 5.7: record workpiece front end to t at the time of exporting temperature measurer₁, rolled piece is calculated by the time of deformed area to temperature measurer are as follows: τ₁=t₁-t_roll。