Dynamic control method of bending roll force in hot rolling finishing mill

Abstract

The present invention discloses a dynamic control method for hot rolling finishing bending roll force, the method comprising: presetting the rolling force deviation change dead zone corresponding to different steel grades and specifications according to the steel grade and specifications of the rolled strip; real-time acquisition of the actual rolling force value after the finishing mill frame bites the steel, and determining the rolling force deviation according to the preset rolling force reference value and the actual rolling force value of the finishing mill frame; calculating the rolling force deviation change at the current moment according to the rolling force deviation at the previous moment and the rolling force deviation at the current moment; judging whether the rolling force deviation change is within the rolling force deviation change dead zone range, if so, taking the preset bending roll force reference value at the previous moment as the preset bending roll force reference value at the current moment, if not, calculating the preset bending roll force reference value at the current moment according to the rolling force deviation change and the preset bending roll force reference value at the previous moment. The method of the present invention can eliminate the influence of frequent changes in rolling force on the strip shape control and improve the strip shape quality.

Description

Technical Field

[0001] The invention relates to the technical field of hot rolling equipment control, and in particular to a method for dynamically controlling hot rolling finishing roll bending force. Background Art

[0002] Hot-rolled strip steel occupies an important position in the entire industrial system, among which strip steel shape is a key indicator to measure whether the quality of hot-rolled strip steel products is qualified. Strip steel shape control is an important technology in strip steel production.

[0003] In the existing hot rolling control process of strip steel, as the rolling unit volume increases and the unit weight of the billet increases, the corresponding rolling force varies with different steel types, resulting in different rolling force changes. Since the rolling force change will cause the strip shape to change, in order to ensure a good strip shape, the pre-controlled bending roll force is currently used to adjust and control the rolling mill rolls to adapt to the rolling changes. Among them, when the rolling force changes, the preset bending roll force is adjusted accordingly.

[0004] However, during the strip rolling process, the actual rolling force changes frequently, and the corresponding preset bending roll force also needs to be adjusted frequently. At this time, when rolling thin strips of the same steel grade, it is easy for the strip to be crushed, and the strip to have side waves or middle waves, which seriously affects the normal production and plate quality of the strip; at the same time, when rolling strips of different steel grades and specifications, it is also easy to have unstable plate shape control problems, which seriously affects the plate quality of the strip. Summary of the invention

[0005] In order to solve part or all of the technical problems existing in the above-mentioned prior art, the present invention provides a method for dynamically controlling the bending roll force of hot rolling finishing rolling.

[0006] The technical solution of the present invention is as follows:

[0007] A method for dynamically controlling the bending force of a hot rolling finishing roll is provided, the method comprising:

[0008] According to the steel grade and specification of the rolled strip, the rolling force deviation change dead zone corresponding to different steel grades and specifications is pre-set;

[0009] The actual rolling force value of the finishing mill frame after biting the steel is collected in real time, and the rolling force deviation is determined according to the preset rolling force reference value and the actual rolling force value of the finishing mill frame;

[0010] Calculating the rolling force deviation variation at the current moment according to the rolling force deviation at the previous moment and the rolling force deviation at the current moment;

[0011] Determine whether the rolling force deviation change is within the rolling force deviation change dead zone. If so, use the preset bending roll force reference value at the previous moment as the preset bending roll force reference value at the current moment. If not, calculate the preset bending roll force reference value at the current moment based on the rolling force deviation change and the preset bending roll force reference value at the previous moment.

[0012] In some possible implementations, the rolling force deviation change dead zone corresponding to different steel grades and specifications is as follows:

[0013] Steel grade specifications Rolling force deviation change dead zone (KN) High silicon steel narrow material -500～500 High silicon steel wide material -800～800 Low silicon steel narrow material -200～200 Low silicon steel wide material -400～400 Carbon steel narrow material -200～200 Carbon steel wide material -300～300 Nickel stainless steel narrow material -300～300 Nickel stainless steel wide material -500～500 Chrome stainless steel narrow material -300～300 Chrome stainless steel wide material -600～600

[0014] Set up;

[0015] Among them, narrow material refers to strip steel with a width less than 1200mm, and wide material refers to strip steel with a width greater than or equal to 1200mm.

[0016] In some possible implementations, the rolling force deviation is calculated using the following formula:

[0017] ΔF=F ref -F act

[0018] Where ΔF represents the rolling force deviation, F ref Indicates the preset rolling force reference value of the finishing mill stand, F act Indicates the actual value of the rolling force after the finishing mill stand bites the steel.

[0019] In some possible implementations, the rolling force deviation variation is calculated using the following formula:

[0020] ΔΔF n =ΔF n -ΔF n-1

[0021] Among them, ΔΔF n Indicates the rolling force deviation change at the nth moment, ΔF n Denotes the rolling force deviation at the nth moment, ΔF n-1 Indicates the rolling force deviation at the n-1th moment.

[0022] In some possible implementations, the preset bending roll force reference value at the current moment is calculated using the following formula according to the rolling force deviation variation and the preset bending roll force reference value at the previous moment;

[0023] W n =W n-1 +T A / T i ×ΔΔF n ×K

[0024] Among them, W nIndicates the preset bending roll force reference value at the nth moment, W n-1 Indicates the preset bending roll force reference value at the n-1th moment, T A represents the sampling time, T i Indicates the integration time, ΔΔF n represents the rolling force deviation change at the nth moment, and K represents the rolling mill characteristic coefficient.

[0025] In some possible implementations, the sampling time is set to 2 ms.

[0026] In some possible implementations, the integration time is set to 1-10 ms.

[0027] The main advantages of the technical solution of the present invention are as follows:

[0028] The dynamic control method of the hot rolling finishing bending roll force of the present invention sets different rolling force deviation change dead zones according to different steel grades. When the rolling force deviation change does not exceed the rolling force deviation change dead zone range, the preset bending roll force is not adjusted and controlled, thereby avoiding the influence of frequent changes in rolling force, eliminating the phenomenon of strip crushing, edge waves or middle waves when rolling strips of the same steel grade, reducing abnormal downtime, and improving the plate shape control stability when rolling strips of different steel grades and specifications, thereby improving the plate shape quality of the strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 The present invention is a flowchart of a method for dynamically controlling the hot rolling finishing roll bending force according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] The technical solution provided by the embodiments of the present invention is described in detail below with reference to the accompanying drawings.

[0033] See also Figure 1An embodiment of the present invention provides a method for dynamically controlling the bending roll force of a hot rolling finishing mill. The method is used for controlling the bending roll force of a finishing mill frame and is put into use when the frame bites steel and is cancelled when the steel is thrown. The method comprises the following steps:

[0034] According to the steel grade and specification of the rolled strip, the rolling force deviation change dead zone corresponding to different steel grades and specifications is pre-set;

[0035] The actual rolling force value of the finishing mill frame after biting the steel is collected in real time, and the rolling force deviation is determined according to the preset rolling force reference value and the actual rolling force value of the finishing mill frame;

[0036] Calculating the rolling force deviation variation at the current moment according to the rolling force deviation at the previous moment and the rolling force deviation at the current moment;

[0037] Determine whether the rolling force deviation change is within the rolling force deviation change dead zone. If so, use the preset bending roll force reference value at the previous moment as the preset bending roll force reference value at the current moment. If not, calculate the preset bending roll force reference value at the current moment based on the rolling force deviation change and the preset bending roll force reference value at the previous moment.

[0038] Specifically, in one embodiment of the present invention, the dynamic control method is implemented by using a primary computer and a computer program of a rolling mill control system during actual use. First, according to the steel grade and specification of the rolled strip, a rolling force deviation change dead zone corresponding to different steel grades and specifications is pre-set in the computer; then, after the finishing mill frame bites the steel, the computer calculates and determines the rolling force deviation based on the actual value of the rolling force of the finishing mill frame after biting the steel collected in real time and the preset rolling force reference value of the finishing mill frame; based on the rolling force deviation, the rolling force deviation change at different times is calculated in real time; and according to the rolling force deviation change and the rolling force deviation, the rolling force deviation is calculated. The preset bending roll force reference value at each moment is determined based on the relationship between the rolling force deviation change dead zone range; when the rolling force deviation change is within the rolling force deviation change dead zone range, the preset bending roll force reference value is kept unchanged, that is, the preset bending roll force reference value is not adjusted; when the rolling force deviation change exceeds the rolling force deviation change dead zone range, the preset bending roll force reference value at the current moment is calculated based on the rolling force deviation change and the preset bending roll force reference value at the previous moment, the preset bending roll force reference value is adjusted based on the calculated preset bending roll force reference value, and then the rolling mill roll is controlled based on the adjusted preset bending roll force reference value.

[0039] It can be seen that the dynamic control method of the hot rolling finishing bending roll force provided by an embodiment of the present invention sets different rolling force deviation change dead zones according to different steel grades. When the rolling force deviation change does not exceed the rolling force deviation change dead zone range, the preset bending roll force is not adjusted and controlled, which can avoid the influence of frequent changes in rolling force, eliminate the phenomenon of strip crushing, edge waves or middle waves when rolling strips of the same steel grade, reduce abnormal downtime, and improve the plate shape control stability when rolling strips of different steel grades and specifications, thereby improving the plate shape quality of the strip.

[0040] In one embodiment of the present invention, the rolling force deviation change dead zone corresponding to different steel grades and specifications is in accordance with the following table:

[0041] Steel grade specifications Rolling force deviation change dead zone (KN) High silicon steel narrow material -500～500 High silicon steel wide material -800～800 Low silicon steel narrow material -200～200 Low silicon steel wide material -400～400 Carbon steel narrow material -200～200 Carbon steel wide material -300～300 Nickel stainless steel narrow material -300～300 Nickel stainless steel wide material -500～500 Chrome stainless steel narrow material -300～300 Chrome stainless steel wide material -600～600

[0042] Set up;

[0043] Among them, narrow material refers to strip steel with a width less than 1200mm, and wide material refers to strip steel with a width greater than or equal to 1200mm.

[0044] High silicon steel includes, for example, silicon steel with a higher silicon content such as DW25 and DW35, low silicon steel includes, for example, silicon steel with a lower silicon content such as DW60 and DW80, carbon steel includes, for example, iron-carbon alloys with a carbon content of 0.0218% to 2.11% such as Q195 and Q235, nickel stainless steel includes, for example, 300 series stainless steel such as 301 and 304, and chromium stainless steel includes, for example, 400 series stainless steel such as 430 and 443.

[0045] By controlling the finishing rolling bending roll force according to the rolling force deviation change dead zone corresponding to the different steel grades and specifications specifically set above, it is possible to ensure the shape quality of the strip after rolling while eliminating the influence of frequent changes in rolling force.

[0046] Furthermore, in one embodiment of the present invention, the rolling force deviation is calculated using the following formula:

[0047] ΔF=F ref -F act

[0048] Where ΔF represents the rolling force deviation, F ref Indicates the preset rolling force reference value of the finishing mill stand, F act Indicates the actual value of the rolling force after the finishing mill stand bites the steel.

[0049] Further, taking the calculation of the rolling force deviation change at the nth moment as an example, the rolling force deviation change is calculated using the following formula:

[0050] ΔΔF n =ΔF n -ΔF n-1

[0051] Among them, ΔΔF n Indicates the rolling force deviation change at the nth moment, ΔF n Denotes the rolling force deviation at the nth moment, ΔF n-1 Indicates the rolling force deviation at the n-1th moment.

[0052] Further, taking the calculation of the preset bending roll force reference value at the nth moment as an example, when the rolling force deviation change is not within the rolling force deviation change dead zone, the preset bending roll force reference value at the current moment is calculated using the following formula according to the rolling force deviation change and the preset bending roll force reference value at the previous moment;

[0053] W n =W n-1 +T A / T i ×ΔΔF n ×K

[0054] Among them, W n Indicates the preset bending roll force reference value at the nth moment, W n-1 Indicates the preset bending roll force reference value at the n-1th moment, T A represents the sampling time, T i Indicates the integration time, ΔΔF n represents the rolling force deviation change at the nth moment, and K represents the rolling mill characteristic coefficient.

[0055] Among them, the sampling time of the computer can be set to 2ms according to actual needs, and the integration time of the computer can be set to 1-10ms according to actual needs.

[0056] To make the above technical solution of the present invention clearer, the technical solution of the present invention will be described clearly and completely in combination with examples. Obviously, the described examples are only part of the embodiments of the present invention, not all of the embodiments.

[0057] Example 1

[0058] Taking the F1 stand of the rolling mill as an example, the steel grade specifications of the rolled strip are: carbon steel narrow material with a thickness of 2.0mm and a width of 1050mm; the sampling time of the computer is T A is 2ms; integration time T i It is 2ms, and the rolling mill characteristic coefficient K is 1.3.

[0059] Assume that the preset rolling force reference value of the finishing mill stand is 28000KN, the actual rolling force value at the n-1th moment is 27700KN, and the actual rolling force value at the nth moment is 27500KN. At this time, the rolling force deviation at the n-1th moment is 28000-27700=300KN, and the rolling force deviation at the nth moment is 28000-27500=500KN. The rolling force deviation variation of the stand at this time is ΔΔF n = (500)-(300) = 200KN. Since the rolling force deviation of the corresponding steel grade has a dead zone of -200 to 200KN, the rolling force deviation variation falls within the dead zone (-200 ≤ ΔΔF n ≤200), the bending roll force control is not pre-adjusted to reduce the impact of frequent changes in rolling force deviation on plate shape control.

[0060] Assume that the preset rolling force reference value of the finishing mill stand is 28000KN, the actual rolling force value at the nth moment is 27500KN, and the actual rolling force value at the n+1th moment is 27200KN. At this time, the rolling force deviation at the nth moment is 28000-27500=500KN, and the rolling force deviation at the n+1th moment is 28000-27200=800KN. The rolling force deviation variation of the stand at this time is ΔΔF n It is (800)-(500)=300KN. Since the rolling force deviation change dead zone of the corresponding steel grade specification is -200~200KN, at this time, the rolling force deviation change exceeds the dead zone range, and the bending roll force is adjusted and controlled according to the above-mentioned bending roll force reference value calculation formula.

[0061] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0062] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for dynamically controlling the bending force of hot rolling finishing rolls, characterized in that: include: According to the steel grade and specification of the rolled strip, the rolling force deviation change dead zone corresponding to different steel grades and specifications is pre-set; The actual rolling force value of the finishing mill frame after biting the steel is collected in real time, and the rolling force deviation is determined according to the preset rolling force reference value and the actual rolling force value of the finishing mill frame; Calculating the rolling force deviation variation at the current moment according to the rolling force deviation at the previous moment and the rolling force deviation at the current moment; Determine whether the rolling force deviation variation is within the rolling force deviation variation dead zone. If so, use the preset bending roll force reference value at the previous moment as the preset bending roll force reference value at the current moment. If not, calculate the preset bending roll force reference value at the current moment based on the rolling force deviation variation and the preset bending roll force reference value at the previous moment. The rolling force deviation change dead zone corresponding to different steel grades and specifications is as follows: Set up; Among them, narrow material refers to strip steel with a width less than 1200mm, and wide material refers to strip steel with a width greater than or equal to 1200mm; According to the rolling force deviation change and the preset bending roll force reference value at the previous moment, the preset bending roll force reference value at the current moment is calculated using the following formula; W n =W n-1 +T A / T i ×ΔΔF n ×K Among them, W n Indicates the preset bending roll force reference value at the nth moment, W n-1 Indicates the preset bending roll force reference value at the n-1th moment, T A represents the sampling time, T i Indicates the integration time, ΔΔF n represents the rolling force deviation change at the nth moment, and K represents the rolling mill characteristic coefficient.

2. The dynamic control method of hot rolling finishing roll bending force according to claim 1 is characterized in that: The rolling force deviation is calculated using the following formula: ΔF=F ref -F act Where ΔF represents the rolling force deviation, F ref Indicates the preset rolling force reference value of the finishing mill stand, F act Indicates the actual value of the rolling force after the finishing mill stand bites the steel.

3. The dynamic control method of hot rolling finishing roll bending force according to claim 1 is characterized in that: The rolling force deviation variation is calculated using the following formula: ΔΔF n =ΔF n -ΔF n-1 Among them, ΔΔF n Indicates the rolling force deviation change at the nth moment, ΔF n Denotes the rolling force deviation at the nth moment, ΔF n-1 Represents the rolling force deviation at the n-1th moment.

4. The method for dynamic control of hot rolling finishing roll bending force according to claim 1, characterized in that: The sampling time is set to 2 ms.

5. The method for dynamic control of hot rolling finishing roll bending force according to claim 1, characterized in that: The integration time is set to 1-10 ms.

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