WO1986001440A1 - Method of controlling winding temperature in hot rolling - Google Patents

Abstract

A method for controlling winding temperature controls the cooling rate in the cooling step in hot rolling and controls the longitudinal pattern of a coil. The temperature of the coil piece in each cooling section is estimated by means of a state observer, thereby highly accurately effecting forecast control and feedback control. Further, a target temperature value in each cooling section is set as desired, whereby any desired cooling temperature gradient pattern is obtained, and the setting of the target temperature value in each cooling section is changed with the movement of the strip. Thus, it is possible to highly accurately control the winding temperature in the hot rolling.

Description

 Winding temperature control method for fine hot E rolling Technical field

 The present invention also relates to a winding temperature control method for realizing the cooling rate control and the coil longitudinal pattern control in the hot rolling cooling process. Background technology

 Finishing in hot E rolling The winding temperature after E rolling is a strip. The so-called winding temperature control is indispensable because it has a great influence on the quality of the steel, especially on the mechanical strength and workability. Furthermore, the strip from the exit temperature of the finishing E-roller to the winding temperature. The so-called cooling rate control and temperature in the longitudinal direction of the string during the cooling process. Turn control-also has a great influence on the quality of hot E rolling, so cold speed control and strut in these processes are in recent years. It is required to change the target value of the coiling temperature in the longitudinal direction of the strip so that the coil temperature distribution after coiling becomes constant during air cooling.

However, it is difficult to install a thermometer for each sector, which is necessary for cooling rate control, due to the physical layout of the cooling device on the runout tray and the problem of the thermometer measurement environment. Comb and string. Conventionally, the method of changing the longitudinal winding temperature is

O PI Steel type size could not be quantitatively determined.

 Although it was originally proposed against this background,

5 8-1 5 2 0 2 Publication, "Method for controlling winding temperature of hot rolled steel sheet" and "Panel for controlling winding temperature of hot rolled steel sheet", Japanese Patent Laid-Open No. 5 3-2370 There is.

The former divides the cooling process into evenly spaced sections, and determines the required number of cooling sections required for a given winding temperature based on the acceleration / deceleration rate of the E-roller. In this method, the cooling rate is corrected according to the set acceleration / deceleration rate, so corrections due to operator intervention, etc., are still errors. As for the cooling rate, there is a problem in the evaluation of the cooling rate due to the temperature gradient on the run-out nozzle; ^ one-feed control.

The latter is the cooling rate of each section, the speed of the strip, and the output temperature of the section determined by the output side target temperature of the preceding section. Based on the target temperature and heat transfer coefficient, etc., the number of laminar heads to be injected should be selected and determined, as well as the coil thickness, coil speed, and the selected laminar < Based on the track record such as the number of headers, the outlet side temperature for each section is calculated using a model formula that uses the heat transfer coefficient, and a model is generated when there is an error with the actual temperature. It is a feedback control that modifies the parameters of the expression. However, many of the parameters are non-linear with respect to the coil temperature, so there is a problem in the accuracy of the estimation calculation and the speed of correcting the hall parameters.

C? ヽ In addition, the temperature in the longitudinal direction of the coil. Conventionally, the turn of the coil was performed at the tip of the coil and the tracking of the tail was performed, and the specified section was not injected without water only when passing through the tip and the tail force runout trail. I have come up with a method. However, with this conventional method, it is difficult to judge the quality of the cooling rate in terms of quality control and control. With regard to turns, it is difficult to control the temperature at the tip of the coil and the temperature at the end of the tail to the desired center through the respective steel grade sizes. Disclosure of the invention

 The present invention relates to the hot rolling quality control described above, particularly the temperature in the longitudinal direction of the coil. It is an object of the present invention to provide a winding temperature control method capable of accurately performing turn control.

 In order to achieve the above-mentioned object, in the present invention, the temperature of the coil piece in each cooling section is estimated and calculated by the state observing device (other). The temperature of the coil pieces in the hot water area cannot be installed because of the environmental impact, and the predictive control and feedback control are performed with high accuracy, and the preconditioning equipment conditions and operation By arbitrarily setting the temperature target value of each cooling section calculated for the conditions, etc., it is possible to obtain an arbitrary cooling temperature gradient pattern. Change the target value of the sequence one by one according to the movement of the string °.

 The invention is constructed and carried out as described above.

OMPI is there. This has the following three effects.

 (1) When an error occurs between the final estimated value of the section and the actual temperature, the actual temperature compensation corrects each of the estimated section values promptly, resulting in quick control response. The winding temperature accuracy is greatly improved.

 (2) Since the temperature adjustment value in each cooling section is calculated as an absolute value each time the coil advances, the temperature gradient on the runout ^ is clearly estimated. it can . Therefore, it is possible to estimate the temperature of the bathhouse where the thermometer cannot be installed in terms of equipment and environment, and it is possible to evaluate the cooling rate in terms of quality control and control. In addition, cooling rate control can be performed with high accuracy.

 (3) Dynamization is performed according to the movement of the coil by adjusting the target values for each section obtained by the preset calculation based on the facility capacity, operating conditions, steel type, size, etc. Since it is set to the mike, temperature pattern control in the longitudinal direction of the coil can be performed with high accuracy.

 Due to the various effects as described above, it is possible to obtain the winding temperature, which is a major factor in determining the quality of the slag, with high accuracy, and at the same time, the quality of the structure can be controlled by the cold speed control. It is possible to manufacture a uniform quality coil by separating and controlling the temperature pattern of the coil longitudinal temperature, improving the yield by reducing the quality of defective steel, and improving the quality of the product. Economic merit such as production is extremely large.

Brief explanation of the drawings

Figure 1 shows the cooling temperature control of the spreading from the finisher exit side to the winder to explain the winding temperature control method of the friend invention. Fig. 2 is a side view showing the process, Fig. 2 is a ^ lock diagram showing the composition of the winding temperature control of the invention, and Fig. 3 is a plan view showing the storage position of the data used in the invention. FIG. 5 is a control block diagram according to the present invention, showing the details of FIG. 2, and FIG. 5 is a diagram showing an example of application effects of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the invention will be specifically described based on the embodiments shown in the drawings.

First of all, to make the explanation easier to understand. The geometric definition of the mouth process is performed as shown in Fig. 1. That is, the finishing thermometer FT and the winding thermometer CT are divided into equal intervals L ₀ without distinction between water-cooling and air-cooling, and the finishing thermometer FT side ^ 1, / ¾ 2 ··· / ¾ ι segment, and the most downstream segment is / ¾ η segment.

The example in Fig. 1 consists of 21 water-cooled sections and 5 air-cooled sections. In Fig. 1, F is a finisher and ΜΤ is an intermediate thermometer.

 Figure 2 shows an overview of the control method of the invention. The control ^ α check that represents this is roughly divided into functions, and the coil piece constant length micro-tracking function Α, state observer B, optimum controller C and actual value are shown. It is divided into four, processing function D.

 (1) Coil fixed length micro-tracking function A

This is because the coil speed is integrated by integrating the coil velocity. The moving distance is calculated, and each time the coil advances the section length L ₀ with the finishing thermometer FT as the starting point, the data transfer is performed for the coil piece. The data to be transferred is work instruction data, etc. that prescribes equipment conditions and operating conditions that are pre-set for each plate thickness H and coil.

(2) State observer B

 Each time the coil piece is irrigated with Lo, work instruction data, coil piece thickness, coil speed, cooling water temperature, FT :, actual values of C Γ, etc. Calculate the temperature Ti by the formula ② oa L

i = (i-!- _w ) X e + _w- (l)

 P · ii c v where Ti: i section output temperature

 Ti .i: i section inlet temperature (measured by FT)

 T w: Cooling water temperature

 i: i-section heat transfer coefficient

 P: Specific gravity

 i: i section plate thickness

 C i: i section specific heat

 v: coil speed

 Is. In addition, Oii and C i are the following numbers. _

i = f (]-!, ητ ι, ηβ ί) (2)

Where n τ i is the number of upper headers

 n B i: Number of lower output heads

 K · Steel type

Is.

From equation (1), the temperature estimation calculation is performed sequentially from the downstream side to the upstream side from the ¾ 1 section force to the ^ 27 section. This is, Ru Oh order to cormorants by other than the co-I-le piece temperature straight near CHAPTERTHREE does not affect the temperature estimation calculation against in the SECTION ₀

 As a result of the calculation in this way, an error Τ Ϊ is generated between the estimated temperature on the outlet side of the / ¾ 27 section and the winding temperature. Allocate to each section. This is the C T pretreatment in Fig. 3, which corresponds to C T actual compensation.

i = -Gi / (1 + TiS) X (CT- T ₂₇ )

 Ti = Ti + Ti —— (4)

Where the section error allocation rate

 TiS: Dead time ha. Glitter

 Ti: i section error allocation amount

 CT: Actual winding temperature value

 Ti: i-side output estimated value

Is.

Therefore, the estimated temperature at the outlet side of each section is predictive control + feedback control according to Eqs. (1) and (4).

(3) Optimal controller C In order to ensure that the estimated value of each section temperature becomes a target value of each section obtained from the pre-cure operating conditions by a constant method considering the response of the pell ^. Find the amount of head output in each section.

First, find the required heat transfer coefficient a for each section. t = -Ci · ν / <L ₀ X ίη (Τ _ί _ ₁ - _W ) C MI -T)>

-— (5) Here, T _M i: i output temperature target value

And ai is a function of coil temperature

 Q! I = fCw, Ti-i, A, B, C) —— (6)

Is. Here,

 A Plate heat transfer coefficient Influence coefficient

 B Water injection amount Heat transfer coefficient Influence coefficient

 C Heat transfer coefficient during air cooling

 Header output coefficient

Is. Also, w has the following relationship depending on the upper and lower water injection conditions.

 w = f, Π i ηβϊ, Ν, ΝΒ, D, Ε) — — (7) where II τ i: upper output header number

 Lower output head number

Ν: Number of upper equipment headers in section Ν _Β : Number of lower equipment headers in section D: Plate upstream water coefficient

Ε: Cooling coefficient of lower header when upper part is 1.0-- Is.

 Therefore, if the header output coefficient w is obtained from Eqs. (5), (6), and (7), the lamina in the work instruction data set for each coil in advance is set. "One upper and one lower in-section output headers are determined depending on whether upper or lower water injection is specified. In addition, at the time of upper and lower water injection, The upper and lower force ratios should be set to 1: 1 in consideration of coil passage on the runout tail.

(4) Actual value processing function D

 The rationality check and filter processing of the σ sese data are performed at regular intervals.

 Next, we will describe concretely how the above four functions (1) to (4) operate in actual control.

 First, when the controlled coil reaches the finishing spreader, the operating conditions of the coil, the equipment conditions at that time, the cooling water temperature record, etc. Sectional output side temperature target value, temperature in the longitudinal direction of the coil. During turn control, the temperature target values on the outlet side of the coil at the tip and tail of the coil, whether the temperature is above the laminator> the bottom, and whether or not lower water injection is performed, and the initial lam The water injection instruction for each header section is obtained by the initial setting calculation formula, and the calculation conditions such as the numerical values of the parameters used in the initial setting calculation at that time are calculated. Together with this, work piece constant length micro-tracking function A data is given as work instruction data.

 The coil fixed length micro-tracking function A is the finishing temperature.

C1.171 Starting from the temperature meter FT, the winding temperature'meter CT is adjusted until the coil is pulled out, depending on the position of the coil at each moment, the final finishing speed, the winding machine The peripheral speed of the wheel, the final finishing stall speed, etc. are switched by successively switching the speed switches, and speed integration is performed. Transfer the plate thickness H and work instruction data, and activate the condition observation function B.

Here, the equipment condition is the cooling capacity of each cooling section, and the operating condition is that the coil is taken out from the finishing E-roller and then wound by the winder. During that period, it was stipulated how many operations should be carried out. The upper water injection is specified, and the upper water injection and lower water injection are specified. In addition, work conditions such as specification of coil steel type, size, target value of coiling temperature, etc. are not included at all c. State observation function B is a fixed length coil coil. According to the plate thickness and work data of the coil pieces transferred by the tracking function A, as shown in Fig. 3, the thickness transfer tail and work instruction table ^ Each data set is carried out in synchronism with the micro coil single-track tracking, and at the same time, each section target value in the work'instruction data is set as a temperature target. Set to the threshold mark.

After that, by estimating the heat transfer coefficient for each section, the laminar grids specified for the upper and lower headers, respectively. Output state and temperature Obtain the heat transfer coefficient 0! From Eq. (9) based on the estimated temperature on the outlet side of each section shown in the specified value table, and set it to the 0! Estimation table respectively.

First, the header output coefficient w is calculated from Eq. (8). .,

wi = (D-HTi + Β · ιΐΒί) / NT + Νβ · E) —— (8) "CLi = A-wi-i -l + B« wi + C —— (9) Each section If the heat transfer coefficient O! I is obtained for each, the estimated temperature at the outlet side of each section is obtained from Eq. (1) and set to the estimated temperature value tag.

After that, if there is a difference between the estimated temperature on the outlet side of the final section and the actual measured value on the winding thermometer, the estimated temperature value is corrected by equation (4).

 Estimate each outlet side temperature using Eq. (1) and make a correction calculation from the actual thermometer value using Eq. (4) to estimate each corrected section temperature. Set the value to the temperature estimate value table. The cooling temperature gradient on the run-out table can be recognized by this.

 The optimum controller D is the controller of FIG. 3 which is data-set by the coil fixed length micro-tracking function A and the state observation function B. Read the contents of the thickness transfer table, temperature target value table, work instruction table and temperature estimated value table shown in the table at a fixed cycle considering the responsiveness of the pellet. Then, the number of output headers for each section was calculated from the actual results of coil speed and cooling water temperature at that timing, and the upper header Bottom

One OMPI — Set each in the dirty. First, the heat transfer coefficient οίi for each section that is necessary to achieve the target temperature on the outlet side of each section is calculated using Equation (5). Next, the header output coefficient _wi is _calculated from Eqs. (9) and (10). Here, the expression αο) is derived from the expression (9).

 i = (C — C) / (Α · Τί -ι + Β) —— (10)

If w i is calculated from the equation (dO) and the water injection status is specified from the work instruction data, the number of output headers for each section can be calculated. Assuming now that the upper and lower output ratios are 1: 1 above and below the laminar head, the formula (8) gives

 ητϊ = ΠΒ Ϊ = η {^,

n = i · CN _T + N _B * E) / (D + E) --- (ID

And

In equation (HI), if the output header number n is larger than the equipment header number N τ, Ν _Β , then η = Ν τ C = Ν _Β ).

The number of output heads for each section is calculated from the above, and these are stored in the upper and lower headers. Then, the actual control output (Lamina-Header-Palds opening / closing instruction) is performed. Figure 4 shows a control block diagram for implementing the control method described above. It can be said that Fig. 4 is a more detailed development of Fig. 2 after arranging the explanations so far. That is, the coil fixed length micro-tracking function A is activated at every movement of the fixed length LQ to transfer data to the state observing device B, and the state observing device B is For racking data transfer processing The coil piece temperature is calculated based on the equation

Correct the estimated temperature based on the actual temperature according to equation (4).

 Based on this result and the contents of various data in the control table shown in Fig. S, the optimum controller c calculates each section according to Eq. (7). The number of output headers for each is calculated and converted to the control operating end output according to the number of output headers, and finally the pel ^ opening / closing control output is instructed as the actual control output.

Figure 5 is grayed La off der Ri steels showing a specific example of the effect of the present invention is ordinary steel (tensile strength 2 0-8 0 / Hall ²⁾ ^ U I le control targets value length ratio + 2 0 In ° C ¾: It shows that the winding temperature applicability when the invention is applied is high, and that the applicability is high with each thickness.

: · '{?:

^T 'one ^r

Claims

 In the cooling process for hot E elongation, cooling is performed between the finishing outlet thermometer and the winding thermometer, and a section with a predetermined interval having a plurality of cooling headers capable of controlling one Harm to! ! However, with the movement of the coil piece equal to the section length, the entrance side that was pre-determined for the equipment condition and operating condition of the coil piece for each section, In addition to setting the target temperature on the outlet side, the temperature of the coil piece on the outlet side of each section is estimated and calculated by a model formula for each movement of the coil piece, while Predetermined cooling is performed by a thermometer placed in the inlet, the temperature of the coil piece on the outlet side is measured to correct the estimated temperature, and the output side target temperature for each section Cooling control for each section based on actual results such as the estimated human side temperature after correction, coil thickness for each section, coil speed, cooling water temperature, etc. A hot-rolling temperature control method characterized by determining the manipulated variable.