JPH06335719A - Method for controlling speed for continuous rolling mill - Google Patents

Abstract

PURPOSE:To prevent a mass flow disturbance when the tip of the material to be rolled is biten into a stand in a continuous rolling milll and refrain the mass flow vibration from the rolling time of the tip. CONSTITUTION:A deviation of DELTAfi+1<l> of a progressive rate when the tip of the material 8 to be rolled is bitten into the i+1 stand, a deviation DELTAHi+1<l> of an inlet side plate thickness and the deviation on DELTAhi+1 of an outlet side plate thickness is estimated from an outlet side plate thickness deviation DELTAhi<l> of the same tip detected on the outlet side of the 1st stand, the roll speed of the 1st stand is controlled in accordance with a quantity of correction DELTAVi obtained by applying each of these deviations to the above-mentioned expressions (the denominations in the expressed indicate reference value). DELTAVi/Vf=DELTAfi/(1+fi)+DELTAfi+1<l>/(1+fi+1)-DELTAHi+1<l>/Hi+1+DELT ARi+1<l>/Ri+1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control method for a continuous rolling mill, and more particularly to a speed control method for a continuous rolling mill which is suitable for suppressing fluctuations in mass flow between stands of a continuous rolling mill.

[0002]

2. Description of the Related Art Conventionally, as a mass flow control technology that does not require direct detection of stand-to-stand tension fluctuations and stand-to-stand loop amount fluctuations, plate thickness fluctuations, which are the largest cause of mass flow fluctuations, are detected and mass flow fluctuations are fed. The method of controlling the roll speed to compensate in the forward direction is
For example, JP-B-51-2061 and JP-A-63-22091.
5 are disclosed.

In the methods disclosed in these publications,
The relational expression represented by the formula (1) for making the i stand stand-out plate speed and the next i + 1-th stand entrance plate speed match,
Speed control is performed as follows based on the variational expression of the following expression (3), which is derived based on the mass flow conservation expression of the (i + 1) th stand expressed by the expression (2).

Vi (1 + f _i ) = V _{i + 1} (1-b _{i + 1} ) ... (1) V _{i + 1} · H _{i + 1} (1-b _{i + 1} ) = V _{i + 1} · h _{i + 1 (1+ f i)} ... (2) ΔVi / Vi = Δ f i / (1+ f i) + Δ f i + 1 / (1+ f i + 1) -ΔH i + 1 / H i + 1 + Δ h _{i + 1} / h _{i + 1} (3)

Here, V is the roll speed, f is the advance rate, and b
Is the reverse travel ratio, H is the entrance side plate thickness, h is the exit side plate thickness, the suffix of each symbol is the stand number, and Δ is the deviation from each value (reference value) in the standard rolling state.

Vi, f _i , f in a certain standard rolling state
and _{i + 1, H i + 1} , h i + 1, the deviation delta f _i of the detected values from the reference values except _{Vi, Δ f i + 1,} ΔH i + 1, the Δ h _{i + 1,}
The roll speed deviation (correction amount) ΔVi of the i-th stand is calculated by applying the above equation (3), respectively, and the actual roll speed Vi (r) of the i-th stand is corrected according to this ΔVi. Suppress fluctuations in mass flow between i + 1 stands.

Therefore, according to the above conventional method, the i-th star
Between the i-th and the (i + 1) th stand by correcting the roll speed
In order to suppress the mass flow fluctuation of the
After being bitten into the (i + 1) th stand,
Deviation of the advance rate at_i, And the i + 1th stand
Deviation of the advance rate at_{i + 1}, Entry-side thickness deviation ΔH
_{i + 1}, Deflection of outlet plate thickness Δ h_{i + 1}Need to detect.

[0008]

However, when there is an error in the initial setting of the rolling conditions, the initial mass flow disturbance becomes large immediately after the tip of the material to be rolled is bitten into the (i + 1) th stand. However, if each deviation is detected after the tip of the material to be rolled is bitten into the (i + 1) th stand as described above, there is a problem that it is impossible to suppress the mass flow fluctuation at the tip of the material to be rolled.

The present invention has been made to solve the above-mentioned conventional problems, and prevents the occurrence of initial mass flow disturbance immediately after the tip of the material to be rolled is bitten into the rolling stand in the continuous rolling mill, An object of the present invention is to provide a speed control method for a continuous rolling mill capable of effectively suppressing the mass flow fluctuation from the tip of the material to be rolled.

[0010]

The present invention provides a continuous rolling mill.
Deviation Δf of the leading rate in the i-th stand_i,common
In the next i + 1th stand,
Difference ΔH_{i + 1}, Deflection of outlet plate thickness Δ h_{i + 1}And deviation of advanced rate
Δ f_{i + 1}According to the roll speed correction amount ΔVi calculated using
Continuously, the roll speed of the i-th stand is corrected and controlled.
In the speed control method of the rolling mill, the
When the tip of the rolled material is caught
Difference ΔH_{i + 1} ^t, Deflection of outlet plate thickness Δ h_{i + 1} ^tAnd advanced rate
Deviation Δ f _{i + 1} ^tIs measured at the outlet side of the i-th stand.
Deviation of strip thickness at the tip of the rolled material Δ h_i ^tPredict based on
By doing so, the above problems are solved.

According to the present invention, in the above speed control method for a continuous rolling mill, the deviation ΔH _{i + 1} ^t between the inlet side plate thickness and the outlet side plate thickness when the tip of the material to be rolled is caught in the (i + 1) th stand. Deviation Δ h _{i + 1} ^t and deviation of advanced rate Δ f
_{i + 1} ^t is ^expressed by the following equation ΔH _{i + 1} ^t = Δh _i ^t (4) Δh _{i + 1} ^t = {1 / (M _{i + 1} + Q _{i + 1} )} (∂P / ∂ H) _{i + 1}・ ΔH _{i + 1} ^t (5) Δ f _{i + 1} ^t = (∂f / ∂H) _{i + 1}・ ΔH _{i + 1} ^t + (∂f / ∂h) _{i + 1}・Δh _{i + 1} ^t (6) (M: Mill constant, Q: Plastic constant, (∂P / ∂H): Influence coefficient of load on the plate thickness on the input side, (∂f / ∂H): Input of advanced ratio effect counted against side thickness, (∂f / ∂h): determined from relative thickness at delivery side of the forward slip influence coefficient), the roll speed correction amount [delta] Vi of the i stands, the following formula _{ΔVi / Vi = Δ f i /} (1+ f _i ) + Δf _{i + 1} ^t / ( ₁ + f _{i + 1} ) −ΔH _{i + 1} ^t / H _{i + 1} + Δ h _{i + 1} ^t / h _{i + 1} (7) is there.

[0012]

In the present invention, the correction amount Δ is calculated from the equation (3).
When Vi is calculated and the roll speed of the i-th stand is controlled, the deviation Δf _{i + 1} ^t of the advance rate when the tip of the rolled material is bitten by the i + 1-th stand and the deviation ΔH of the inlet side plate thickness _{i + 1}
The ^t and exit side thickness deviation Delta] h _{i + 1} ^t, since as predicted based on the i-th stand outlet side in the actually measured tip of delivery side thickness delta h _i ^t of the rolled material, the material to be rolled Tip is i +
Before being bitten by one stand, the actual roll speed Vi (r
) Can be corrected, it is possible to suppress the initial mass flow disturbance that occurs at the moment (immediately after) the tip of the rolled material is bitten by the (i + 1) th stand.

[0013] In the present invention, definitive when the leading end of the rolled material is caught to the i +1 stand, entry side thickness deviation [Delta] H i _{+ 1} ^t, out of the side plate thickness deviation Δ h _{i + 1} of ^t and forward slip The deviation Δf _{i + 1} ^t is obtained from the equations (4) to (6), and the roll speed correction amount ΔVi of the i-th stand is obtained from the equation (7) corresponding to the equation (3). Is
Since ΔH _{i + 1} ^t , Δh _i ^t, and Δ f _{i + 1} ^t can be predicted with high accuracy, ΔVi can be accurately obtained.

Therefore, the roll speed of the i-th stand immediately after the tip of the rolled material is bitten into the (i + 1) -th stand is
Before the tip of the material to be rolled is actually bitten into the (i + 1) th stand, it can be corrected in advance using the correction amount ΔVi and appropriately controlled. It is possible to effectively prevent fuss flow fluctuations.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is an explanatory view showing the essential structure of a continuous rolling mill applied to an embodiment of the present invention.

The continuous rolling mill has a plurality of rolling stands (only the i-th stand and the (i + 1) th stand are shown in the figure).
Each of the rolling stands includes a work roll 10 that rolls the material (strip) 8 to be rolled, a backup roll 12 that reinforces the work roll 10, and a rolling load for detecting the rolling load via the backup roll 12. A load meter 14 and a rolling position detecting device 16 for detecting the rolling position of the work roll 10 are provided.

A plate thickness gauge 18 for measuring at least the outgoing plate thickness of the material 8 to be rolled is installed on each stand.
The deviation Δh _i from the reference value of the outlet side plate thickness at the i-th stand detected by the plate thickness gauge 18 is input to a computer 30 for controlling the entire continuous rolling mill.

In this embodiment, the tip of the material 8 to be rolled is rolled by the i-th stand, and immediately after passing through the stand, the deviation Δh _i ^t of the outgoing side plate thickness is detected by the plate thickness gauge 18. . The deviation detected by the plate thickness gauge 18 is calculated by the computer 3
When the value is input to 0, the computer 30 uses the above (4)-
According to the equation (6), ΔH _{i + 1} ^t , Δh _{i + 1} ^t and Δ f
_{i + 1} ^t is predicted and calculated, and the calculation result is applied to the equation (7) to calculate the correction amount ΔVi.

Correction amount ΔVi calculated by the computer 30
Is output to the roll driving unit (not shown) of the first stand before the tip of the rolled material 8 is bitten by the (i + 1) th stand, and the roll speed of the i-th stand is adjusted based on the correction amount ΔVi. Correct and control to an appropriate rolling speed.

As described above, according to this embodiment, the
The start timing of the mass flow control between the i-th and the (i + 1) th stands, which is after the tip of the rolled material 8 is bitten into the (i + 1) th stand, is advanced to before the tip is bitten into the (i + 1) th stand. It becomes possible.

As a result, when the tip is bitten by the (i + 1) th stand, the roll speed of the (i) th stand can be appropriately controlled, and immediately after the tip of the rolled material 8 is bitten by the (i + 1) th stand. It is possible to suppress the initial disturbance of the mass flow between the (i) th and (i + 1) th stands that occurs in the above.

Therefore, when the tip of the rolled material 8 is bitten by the (i + 1) th stand, it is possible to reduce the width breakage caused by the over tension due to the unbalance of the roll speed between the stands. Along with being able to accelerate the start timing of mass flow control,
Since the start timing of automatic plate thickness control by AGC (Automatic Gauge Control) can be advanced, it is also possible to reduce the tip off gauge length.

FIGS. 2 and 3 show the sixth to seventh cases in which the initial plate thickness error of +100 μm generated at the sixth stand and the seventh stand is corrected by the absolute value AGC in the continuous rolling mill having seven stands. FIG. 2 is a control result when the control according to the present invention is applied, and FIG. 3 is a control result when the control is not applied. In the figure, the horizontal axis is time [sec
], The vertical axis represents the roll rotation speed [mpm].

As shown in FIG. 3, when the control according to the present invention is not applied, the plate by the AGC for the sixth stand and the seventh stand is kept with the actual roll speed V6 (r) of the sixth stand being constant. Since the thickness correction is performed, both the sixth stand outlet side plate speed Va and the seventh stand inlet side plate speed Vb fluctuate, and at the instant t ₁ when the tip of the rolled material is caught in the seventh stand. Since Va ≠ Vb, this is the initial disturbance of the mass flow.

On the other hand, when the control according to the present embodiment is applied, as is apparent from FIG. 2, after t ₁ at which the tip of the material to be rolled is caught in the sixth stand, the roll of the sixth stand is rolled. Since the speed V6 (r) is being corrected and controlled, the moment the tip of the rolled material is caught in the 7th stand
At t ₂ , it is possible to match the plate speed on the 6th stand exit side with the plate speed on the 7th stand side and set Va = Vb, and as a result, it is possible to prevent the initial disturbance of the mass flow. I understand.

The present invention has been specifically described above, but the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the above-described embodiment, the case where the deviation Δh _i of the outgoing side plate thickness from the plate thickness gauge 18 is input to the computer 30 is shown. However, the outgoing side plate thickness h _i is input to the computer 30 and the deviation is calculated there. It goes without saying that you may ask for.

[0029] In addition, based on the ^{_{Δ h i t, ΔH i +}} 1 t, Δ
The equations used to predict h _{i + 1} ^t and Δf _{i + 1} ^t are not limited to the equations (4) to (6), and the equation for calculating the speed correction amount ΔVi is not limited to the equation (7). .

[0030]

As described above, according to the present invention,
In a continuous rolling mill, it is possible to prevent the occurrence of initial mass flow disturbance when the tip of the material to be rolled is bitten by the stand, and suppress the mass flow variation between stands from the time of rolling the tip.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main configuration of a continuous rolling mill applied to an embodiment according to the present invention.

FIG. 2 is a diagram showing a control result when the present invention is applied.

FIG. 3 is a diagram showing a control result when the present invention is not applied.

[Explanation of symbols]

 8 ... Rolled material 10 ... Work roll 12 ... Backup roll 14 ... Load meter 16 ... Roll-down position detection device 30 ... Calculator

Claims (2)

[Claims] 1. An i-th stand constituting a continuous rolling mill.
Deviation of advanced rate_i, And the next i + 1 stun
Deviation of entrance side plate thickness ΔH_{i + 1}Deviation of output thickness
Δ h _{i + 1}And the deviation of the advanced rate Δ f_{i + 1}Calculate using
Roll of the i-th stand according to the roll speed correction amount ΔVi
In the speed control method of the continuous rolling mill that corrects and controls the speed
When the tip of the material to be rolled is caught in the (i + 1) th stand,
Deviation of inlet plate thickness ΔH_{i + 1} ^t, Deflection of outlet plate thickness Δ
 h_{i + 1} ^tAnd the deviation of the advanced rate Δ f_{i + 1} ^tThe i stand
Deviation Δh of the strip thickness at the tip of the rolled material measured on the outlet side of_i
^tThe speed of the continuous rolling mill characterized by the prediction based on
Degree control method. 2. The deviation ΔH _{i + 1} ^{t in} the inlet side plate thickness and the deviation Δ in the outlet side plate thickness when the tip of the material to be rolled is bitten into the (i + 1) th stand.
h _{i + 1} ^t and deviation Δ f _{i + 1} ^t of forward slip, respectively, the following equation ^{_{ΔH i + 1 t = Δ h}} i t Δ h i + 1 t = {1 / (M i + 1 + Q i + ₁ )} (∂P / ∂
H) _{i + 1} · ΔH _{i + 1} ^t Δ f _{i + 1} ^t = (∂f / ∂H) _{i + 1} · ΔH _{i + 1} ^t + (∂f
/ ∂h) _{i + 1}・ Δh _{i + 1} ^t (M: Mill constant, Q: Plastic constant, (∂P / ∂H): Influence coefficient of load on the plate thickness on the inlet side, (∂f / ∂H): Calculated from the coefficient of influence of the advanced rate on the incoming side plate thickness, (∂f / ∂h): the coefficient of influence of the advanced rate on the outgoing side plate thickness, and the roll speed correction amount ΔVi of the i-th stand is calculated as _i / (1 + f _i ) + Δ f _{i + 1} ^t /
( ₁ + f _{i + 1} ) −ΔH _{i + 1} ^t / H _{i + 1} + Δh _{i + 1} ^t / h
A speed control method for a continuous rolling mill, characterized by being obtained from _{i + 1} .