A method for temperature control of a finishing mill

Abstract

This invention discloses a temperature control method for a finishing mill, comprising the following steps: Step 1, high-temperature gauge detection at the finishing mill inlet; Step 2, temperature determination; Step 3, model selection; Step 4, monthly reading of cooling water and ambient temperatures; Step 5, FTC model control. This invention improves the accuracy of the basic data sources for model calculations, such as the finishing mill inlet temperature, temperature coefficient, and water temperature, thereby enhancing the feedback and self-learning capabilities during model execution control. Ultimately, this improves the final rolling temperature hit rate, ensuring product performance stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of strip rolling model setting and control in hot rolling mill, in particular to a finishing mill temperature control method. BACKGROUND

[0002] The finishing mill starting temperature plays an important role in the setting process of the FTC model, and its instability directly leads to fluctuations in mill speed and water spray setting, causing unstable parameter control and temperature control disorder, so standardizing control of the finishing mill inlet temperature is of great significance. Whether the temperature at the finishing mill inlet is stable directly determines whether the final rolling temperature calculation is accurate. If the finishing mill inlet temperature fluctuates within a relatively narrow range, it is very beneficial to the control of the final rolling temperature at the finishing mill outlet, and the hit rate is relatively high. However, if the temperature fluctuation at the finishing mill inlet is large, especially when the inlet temperature is lower than the conventional temperature, the rolling is very unstable. With different steel inlet temperatures, the surface temperature and core temperature difference are different, and the lower the steel inlet temperature, the greater the temperature difference, and the smaller the temperature drop of the strip between the racks. The original model calculates the temperature drop coefficient of each rack under different steel inlet temperatures, which leads to overestimation of the temperature drop of each rack when the slab inlet temperature is low, resulting in inaccurate calculation of the finishing mill temperature and very low hit rate of the final rolling temperature control at the finishing mill outlet. In addition, the ambient temperature in the plant and the temperature of the cooling water between the racks will change with the seasons, and the changed water temperature and ambient temperature will affect the accuracy of the temperature drop calculation of the strip. Because the ambient temperature and water temperature in the original model are constant, the model cannot obtain the data of the ambient temperature and water temperature at any time, which ultimately affects the control of the final rolling temperature. The above factors ultimately seriously affect the performance, organization form and grain size of the strip, and have an impact on the subsequent product application. SUMMARY

[0003] The purpose of the present application is to provide a finishing mill temperature control method to solve the problems raised in the background art.

[0004] To achieve the above purpose, the present application provides the following technical solutions:

[0005] A finishing mill temperature control method, comprising the following steps: step one, finishing mill inlet pyrometer detection; step two, temperature determination; step three, model selection; step four, reading the cooling water and ambient temperature by month; step five, FTC model control.

[0006] In the above step one, the temperature at the finishing mill inlet is accurately detected.

[0007] In the above step two, it is accurately determined whether the temperature at the finishing mill inlet is higher than 980℃.

[0008] In the above step three: according to whether the temperature is higher than 980 DEG C, corresponding "original model control mode" and hierarchical control mode are selected;

[0009] In the above step four: in the model, the function of reading the water temperature and the environmental temperature in the workshop by month is added;

[0010] In the above step five: finally, the FTC model is used to control the whole.

[0011] Preferably, in the step three, the original model control mode comprises the following steps: S1, inter-stand cooling water cooling coefficient 1; S2, inter-stand lubricating water cooling coefficient 1; S3, radiation cooling coefficient 1; the hierarchical control mode comprises the following steps: F1, adding descaling water cooling coefficient 1; F2, inter-stand cooling water cooling coefficient 2; F3, inter-stand lubricating water cooling coefficient 2; F4, radiation cooling coefficient 2.

[0012] Preferably, in the step three, the original model is that the measured value of the high temperature meter after the rough rolling machine R2 is subtracted by the temperature drop of the intermediate blank in the intermediate roll and the hot coil box, and the temperature is taken as the temperature of the finishing rolling entrance, the measured result of the high temperature meter after rough rolling is often distorted due to the poor measurement environment, and the calculation deviation of the intermediate blank temperature drop in the intermediate roll is large; an additional high temperature meter at the finishing rolling entrance is added, the measurement value is taken as the calculation temperature of the strip steel at the finishing rolling entrance, and participates in the model setting, so that the influence of the measurement distortion of the rough rolling high temperature meter and the inaccurate intermediate roll blank temperature drop calculation on the finishing temperature is avoided.

[0013] Preferably, in the step three, the model hierarchical control is performed on the finishing rolling entrance temperature, different temperature coefficients are used for different layers of the strip steel temperature, and on the basis of the original, the hierarchical control mode is added, the inter-stand water spraying model is graded: the temperature coefficient variable under the low temperature condition that the finishing rolling entrance temperature is less than 980 DEG C is added, and is valued; the inter-stand lubricating water temperature drop coefficient is graded: the temperature coefficient variable under the low temperature condition that the finishing rolling entrance temperature is less than 980 DEG C is added, and is valued; the finishing rolling radiation temperature drop coefficient is graded: the coefficient variable under the low temperature condition that the finishing rolling entrance temperature is less than 980 DEG C is added, and is valued; the water spraying temperature drop coefficient is split into discof (descaling water spraying temperature drop coefficient) and isccof (inter-stand water spraying temperature drop coefficient), and is respectively valued.

[0014] Preferably, in the step four, in order to alleviate the change of the environmental temperature in the workshop and the temperature of the inter-stand cooling water with the change of the season, the function of reading the water temperature and the environmental temperature in the workshop by month is added in the model, the water temperature and the environmental temperature in each month are input into the model by month, and the model automatically reads the temperature.

[0015] Compared with the prior art, the application has the beneficial effects that:

[0016] The application provides accurate calculation basis for the finish rolling final rolling temperature control model by using the detection data of the newly added high-temperature meter at the finish rolling inlet, and improves the control precision of the model; the model is controlled in layers, the finish rolling inlet temperature is controlled in layers, different steel inlet temperatures of different layers adopt different temperature coefficients, the temperature calculation is more accurate, and the temperature control precision is improved; the plant temperature and the cooling water temperature are accurately output, and are automatically updated with the change of seasons, and the control precision of the model is further improved; through the accuracy improvement of the model calculation basis data sources such as the finish rolling inlet temperature, the temperature coefficient and the water temperature, the feedback and self-learning ability in the model execution control process is improved, the final rolling temperature hit rate index is finally improved, and the stability of product performance is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the finish rolling and coiling area of the application;

[0018] Figure 2 It is a final rolling temperature layered control flowchart of the application.

[0019] Figure 3 It is a monthly environment temperature and water temperature table diagram of the application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the application.

[0021] In the description of the application, it should be noted that the terms “upper”, “lower”, “inner”, “outer”, “front end”, “rear end”, “two ends”, “one end”, “the other end” and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms “first” and “second” are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present application, it should be noted that unless otherwise expressly specified and limited, the terms "mounting", "provided with", "connected", and the like, should be interpreted broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] Please refer to Figure 1 The present application provides an embodiment: a finishing mill temperature control method, comprising the following steps: step one, finishing inlet pyrometer detection; step two, temperature determination; step three, model selection; step four, reading cooling water and ambient temperature per month; step five, FTC model control;

[0024] In the above step one: the temperature of the finishing inlet is accurately detected;

[0025] In the above step two: whether the temperature of the finishing inlet is higher than 980 DEG C is accurately determined;

[0026] In the above step three: according to whether the temperature is higher than 980 DEG C, the corresponding "original model control mode" and the hierarchical control mode are selected;

[0027] In the above step four: the function of reading water temperature and ambient temperature in the plant per month is added in the model;

[0028] In the above step five: finally, the FTC model is used to control the whole.

[0029] The original model control mode in the above step three comprises the following steps: S1, interstand cooling water cooling coefficient 1; S2, interstand lubricating water cooling coefficient 1; S3, radiation cooling coefficient 1; the hierarchical control mode comprises the following steps: F1, new phosphorus removal water cooling coefficient 1; F2, interstand cooling water cooling coefficient 2; F3, interstand lubricating water cooling coefficient 2; F4, radiation cooling coefficient 2.

[0030] The original model in the above step three is to select the high-temperature meter measured value after the roughing mill R2, and subtract the temperature drop of the intermediate billet in the intermediate roller way and the hot coil box as the temperature of the finishing inlet. The high-temperature meter after roughing is often distorted due to the poor measurement environment, and the calculation deviation of the intermediate billet temperature drop in the intermediate roller way is large. An additional finishing inlet high-temperature meter is added, and the measurement value is used as the calculation temperature of the finishing inlet strip, which participates in the model setting, avoiding the influence of the roughing high-temperature meter measurement distortion and the intermediate roller way billet temperature drop calculation inaccuracy on the finishing temperature.

[0031] In step three, the model is layered for control, and the entry temperature of the finishing mill is layered. Different temperature coefficients are used for the entry temperature of different layers. On the basis of the original, a layered control mode is added to divide the water spray model between stands into different levels: add temperature coefficient variables under the low temperature condition of finishing mill entry temperature <980℃, and assign values ​​to them.

[0032] Cooling water temperature drop coefficient between racks is categorized as follows:

[0033] A new variable, iscCoffm[std], has been added.

[0034] The original coefficient value iscCof{0.04,0.04,0.04,0.04,0.04,0.04}

[0035] The newly added variable value is iscCoflfm{0.035,0.035,0.035,0.035,0.035,0.035}

[0036] Add relevant procedures:

[0037]

[0038] The temperature drop coefficient of the lubricating water between stands is divided into different levels: a temperature coefficient variable is added under the condition of low temperature (<980℃) at the entry temperature of the finishing mill, and values ​​are assigned;

[0039] The newly added coefficient value is lubCoffm

[0040] The original coefficient value is lubCof{0.2,0.02,0.2,0.2,0.2,0.2,0.2}

[0041] The newly added coefficient value is lubCoffm{0.15,0.015,0.15,0.15,0.15}

[0042] Add relevant procedures:

[0043]

[0044] The radiation temperature drop coefficient of the finishing mill is divided into different levels: the coefficient variable under the low temperature condition of the finishing mill inlet temperature <980℃ is added and a value is assigned;

[0045] The newly added coefficient is radCoffm

[0046] The original coefficient is: radCof: 1.7

[0047] New variable value: radCofm: 1.6

[0048] Add relevant procedures:

[0049]

[0050]

[0051] The spray water temperature drop coefficient is broken down into discof (descaler spray water temperature drop coefficient):

[0052] Fdb.dspCof[0][0]=0.011

[0053] Fdb.dspCof[0][1]=0.011

[0054] Fdb.dspCof[0][2]=0.012

[0055] Fdb.dspCof[1][0] = 0.008;

[0056] isccof (inter-rack water spray temperature drop coefficient):

[0057] Fdb.iscCof[1] = 0.04

[0058] Fdb.iscCof[2]=0.04

[0059] Fdb.iscCof[3]=0.04

[0060] Fdb.iscCof[4]=0.04

[0061] Fdb.iscCof[5] = 0.04

[0062] Fdb.iscCof[6] = 0.04.

[0063] In step four, to mitigate the seasonal variations in ambient temperature within the factory and cooling water temperature between racks, a function was added to the model to read the water temperature and ambient temperature within the factory on a monthly basis. The water temperature and ambient temperature for each month are input into the model, and the model automatically reads the temperature.

[0064] Any aspects of this invention not described in detail are well-known to those skilled in the art.

[0065] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A finishing mill temperature control method comprising the steps of: Step one, the finishing mill entrance high temperature detector detects; Step two, temperature determination; Step three, model selection; Step four, reading the cooling water and ambient temperature per month; Step five, FTC model control; Its characterized in that: In the above step one: the temperature of the finishing mill entrance is accurately detected; In the above step two: whether the temperature of the finishing mill entrance is higher than 980 DEG C is accurately determined; In the above step three: according to whether the temperature is higher than 980 DEG C, the corresponding original model control mode or layered control mode is selected; In the above step four: the function of reading the water temperature and the ambient temperature in the plant per month is added in the model; In the above step five: the FTC model is finally used to control the whole; The original model control mode in the step three includes: interstand cooling water temperature drop coefficient, interstand lubricating water temperature drop coefficient and radiation temperature drop coefficient; The layered control mode includes: newly added phosphorus removal water temperature drop coefficient, interstand cooling water temperature drop coefficient, interstand lubricating water temperature drop coefficient and radiation temperature drop coefficient; The model layered control in the step three divides the finishing mill entrance temperature into layers, and different temperature coefficients are used for different steel inlet temperatures; On the basis of the original, the layered control mode is added, the interstand water spraying model is divided into grades: the temperature coefficient variable under the low temperature condition that the finishing mill entrance temperature is less than 980 DEG C is added, and is valued; The interstand lubricating water temperature drop coefficient is divided into grades: the temperature coefficient variable under the low temperature condition that the finishing mill entrance temperature is less than 980 DEG C is added, and is valued; The finishing mill radiation temperature drop coefficient is divided into grades: the coefficient variable under the low temperature condition that the finishing mill entrance temperature is less than 980 DEG C is added, and is valued; The water spraying temperature drop coefficient is divided into the phosphorus removal water spraying temperature drop coefficient and the interstand water spraying temperature drop coefficient, and is respectively valued.

2. A finishing mill temperature control method according to claim 1, characterized in that: The original model in the step three is that the high temperature detector measured value after the roughing mill R2 is subtracted by the temperature drop of the intermediate billet in the intermediate roll and the hot coil box as the temperature of the finishing mill entrance; Because the measurement environment of the high temperature detector after the roughing mill is relatively poor, the measurement result is often distorted, and the calculation deviation of the intermediate billet temperature drop in the intermediate roll is large; A finishing mill entrance high temperature detector is added, the measurement value of which is used as the calculation temperature of the finishing mill entrance strip, and is used for model setting, which avoids the influence of the roughing mill high temperature detector measurement distortion and the intermediate roll billet temperature drop calculation inaccuracy on the finishing temperature.

3. The finishing mill temperature control method of claim 1, wherein: In order to alleviate the change of the ambient temperature in the plant and the temperature of the interstand cooling water with the change of the season, the function of reading the water temperature and the ambient temperature in the plant per month is added in the model, the water temperature and the ambient temperature in each month are input into the model per month, and the model automatically reads the temperature.

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