JP3438335B2 - How to change the setting during running of the rolling mill - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention connects rolled materials having different materials, plate thicknesses, etc. by welding and continuously rolls them with a rolling mill, while changing the roll gap and roll speed during rolling operation. The present invention relates to a control method for changing running settings of a rolling mill.

[0002]

2. Description of the Related Art In order to prevent a reduction in rolling efficiency due to a setup change when rolling materials to be rolled having different base materials and dimensions, and to omit the striping work, etc. The materials to be rolled are sequentially welded together and supplied to the rolling mill in a state where they are connected to each other, and the roll gap and roll speed of each stand are adjusted to the roll gap and roll of the preceding rolled material at the timing when the welding point passes. There is a method of changing the running setting from the speed to each set value for the succeeding rolled material.

By the way, since the roll gap and the roll speed are in a transitional state apart from the original setting values during the change of the running distance setting, the tension on the inlet side and the outlet side of the rolling stand does not match the set tension, and At the moment when the welding point reaches the rolling stand, a sudden change in tension occurs due to changes in the strip width, strip thickness, material, etc. of the material to be rolled, making it impossible to roll due to breakage or narrowing of the material to be rolled. In some cases, in order to avoid this, there is a problem in that there is a certain limitation on the variation width of the rolled material to be connected, such as the thickness, width and material.

As a conventional method for suppressing such a tension fluctuation, for example, in the technique disclosed in Japanese Patent Publication No. 53-2143, the roll gap setting device and the roll speed setting device have different setting change speeds and can be synchronized with each other. Nothing
The common setting change time for the roll gap and roll speed is set based on the idea that it is the cause of tension fluctuations. However, with this method, although the roll gap and roll speed are in a transitional transition state and tension fluctuations due to the fact that they do not match the original set values are improved, the method is used at the moment the welding point reaches the rolling stand. No control effect can be obtained for sudden tension fluctuations caused by changes in conditions such as strip width, strip thickness, and material quality.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 60-221109, the roll gap is set so that the welding point of the material to be rolled reaches the rolling stand at a time half the time required for changing the setting of the roll gap. Start changing the settings. In this method, the time required for changing the running distance is equally divided into the preceding rolled material and the following rolled material, so the roll gap and roll speed are in a transitional transition state, and are not the original set values. Time is equally divided between the preceding rolled material and the following rolled material.

However, the amount of tension fluctuation caused by the fact that the roll gap and the roll speed do not match the original set values depends on the plate thickness, plate width and material of the preceding rolled material and the following rolled material. Therefore, the amount of change in tension is not always equally divided between the preceding rolled material and the following rolled material, and the strip width and strip thickness of the strip at the moment the welding point reaches the rolling stand. , There is no suppression effect for abrupt tension fluctuations caused by changes in material and other conditions.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is a stable rolling operation that suppresses the tension fluctuation during the change of the running setting and does not cause the material to be rolled to break. It is an object of the present invention to provide a running distance setting change control method capable of changing the running distance setting between rolled materials having significantly different thicknesses, widths and materials.

[0008]

A running distance setting changing method for a rolling mill according to a first aspect of the present invention continuously rolls a preceding rolling material and a trailing rolling material welded to the preceding rolling material, While the welding point of the rolled material and trailing rolled material passes through the specified rolling stand, or before the rolling point of the rolling stand, the roll gap and roll speed of the rolling stand are changed. In the setting change method, the time from the start of the setting change of the roll gap and the roll speed to the passage of the welding point through the predetermined rolling stand where the setting change was started is required to calculate the rolling load and the advance rate. It is characterized in that it is determined based on the material, plate thickness and plate width of the preceding rolled material and the following rolled material.

In the rolling mill running distance setting changing method according to the second aspect of the invention, the time τ _opt from when the setting change of the roll gap and roll speed is started to when the welding point passes the predetermined rolling stand where the setting change is started. , 0 ≦ τ _opt ≦ T, where T is a roll gap setting change time.

[0010]

In the first aspect of the invention, the time difference between the timing at which the welding point passes the predetermined rolling stand and the timing at which the running setting change of the rolling stand is started is determined by the material and size of the material to be rolled.
By making a decision based on legal specifications, tension fluctuations are suppressed regardless of the plate thickness, plate width, and material of the connected rolled materials.

According to the second aspect of the invention, the time difference between the timing at which the welding point passes the predetermined rolling stand and the start timing for changing the running setting of the rolling stand is required. By setting it to be T or less, the tension fluctuation in the change transient state is suppressed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a block diagram of a rolling mill including five stands to which a rolling mill setting change control method according to the present invention is applied. In the figure, # 1 to # 5 are first to fifth rolling stands, A and B. Indicates a material to be rolled having different material and size specifications . The front end of the material B to be rolled is welded (welding point C) to the rear end of the material A to be continuously connected and continuously supplied in the direction of the white arrow to the rolling mill to be rolled. It has become so.

Roll gap setting devices 11 to 15 and roll speed setting devices 21 to 25 are provided on the first to fifth rolling stands # 1 to # 5, respectively, and are illustrated by signals from the roll gap setting devices 11 to 15. The actuators that are not driven are restrained from driving, and the roll driving motors M _{1 to} M ₅ are restrained from being driven by signals from the roll speed setting devices 21 to 25.

The coil information transmission device 31 has information about the material to be rolled, and outputs this information to the roll gap / roll speed calculation device 32 and the change time calculation device 33. The roll gap / roll speed calculation device 32 calculates the roll gap and roll speed for the material to be rolled next, and calculates the amount of change from the set values of the roll gap and roll speed for the material currently being rolled. , Ask for the time required for that change.

Roll gap / roll speed calculator 32
Each change amount calculated in the roll gap setting device 1
1 to 15 and the roll speed setting devices 21 to 25, and at the same time, they are also input to the change time calculation device 33. The change time calculation device 33 is the roll gap setting device 11 to 1
5 and the start times of the roll gap and roll speed setting changes are calculated based on the required change times of the roll speed setting devices 21 to 25. The setting change time and the setting change start time calculated by the change time calculation device 33 are input to the roll gap setting devices 11 to 15 and the roll speed setting devices 21 to 25. The timing of inputting these data is set in accordance with the timing instruction signal from the setting change timing instruction device 34.

When the running setting change control according to the present invention is performed by using such a rolling mill, first, when the rolling end time for the preceding rolling material A approaches, the coil information transmission device 31 will be used as a follower. Information about the material to be rolled B is given to the roll gap / roll speed calculation device 32, and based on this, the roll gap / roll speed calculation device 32 causes the roll gap change amount ΔS ₁ ... ΔS ₅ in each rolling stand.
, The required change time T _S1 ... T _S5 , the roll speed change amount ΔV ₁ ... ΔV _{5 of} each rolling stand, and the necessary change time T _V1 ... T _V5 are calculated. The data calculated by the roll gap / roll speed calculation device 32 is the change time calculation device 33.
The setting change time T common to the roll gaps and roll speeds of all rolling stands is calculated according to the following equation (1). T = max (T _S1 , ..., T _S5 , T _V1 , ..., T _V5 ) (1)

In the change time calculation device 33, the roll gap / roll speed setting change start time is taken as the time τ _opt from the start of the roll gap / roll speed setting change start until the welding point reaches the setting change target rolling stand. The calculation is performed as follows.

The roll gap and roll speed at the time when the welding point C reaches the rolling stand subject to the setting value change are from the start of the setting change of the roll gap and the roll speed until the welding point reaches the rolling stand subject to the setting change. Time τ
Roll gap change amounts ΔS _{1 to} ΔS ₅ and roll speed change amounts, which are given as functions S _i (τ) and V _i (τ) of (0 ≦ τ ≦ T) and are output from the roll gap / roll speed calculation device 32. It is calculated from ΔV _{1 to} ΔV ₅ , the roll gap, and the roll speed setting change time T.

Further, the welding point C is set and changed based on the information of the rolled materials A and B from the coil information transmission device 31, for example, the material and dimensions, the roll gap S _i (τ) and the roll speed V _i (τ). The rolling stand front tension stress σ _fi ^A (τ) immediately before reaching the rolling stand, the rolling stand back tension stress σ _bi ^A (τ): and the rolling immediately after the welding point C reaches the setting change target rolling stand. Stand front tensile stress σ _fi ^B (τ), relevant rolling stand rear tensile stress σ
Calculate _bi ^B (τ).

These σ _fi ^A (τ), σ _bi ^A (τ), σ
_{In fi} ^B (τ) and σ _bi ^B (τ), the roll gap and roll speed are in a transitional transition state, and the tension fluctuations that are not at the original set values do not increase, so that the following (2) to
Determine so that the condition shown in equation (5) is satisfied. C ₁ ≦ σ _fi ^A (τ) / σ _fci ^A ≦ C _u … (2) C ₁ ≦ σ _bi ^A (τ) / σ _bCi ^A ≦ C _u … (3) C ₁ ≦ σ _fi ^B (τ) / σ _fci ^B ≦ C _u (4) C ₁ ≦ σ _bi ^B (τ) / σ _bCi ^B ≦ C _u (5) where σ _fci ^A is the i-th rolling stand front tension stress setting value of the preceding rolled material. σ _bCi ^A : Back tension tension set value of the i-th rolling stand of the preceding rolling material σ _fci ^B : i-th rolling stand front tension stress setting of the following rolling material σ _bCi ^B : i-th rolling of the following rolling material Stand rear tension stress set values C ₁ and C _u : constants defining the allowable range of fluctuations in tension stress

Further, the following formula (6) is used so that the rapid tension fluctuation caused by the change of the plate thickness, plate width and material of the rolled material after the welding point C passes through the rolling stand is suppressed. The minimum time τ is defined as τ _opt .

Max (| σ _fi ^A (τ) −σ _fi ^B (τ) |, | σ _bi ^A (τ) −σ _bi ^B (τ) |) (6) where i = 1 to 5, that is, The time τ _opt from the start of the set time of the rolling stand to the passage of the welding point C through the rolling stand is set according to the material and dimensions of the material to be rolled.

The roll gap change amount ΔS ₁ ... ΔS ₅ , roll speed change amount ΔV ₁ ... ΔV ₅ , roll gap, roll speed common setting change time T, roll gap, The time τ _opt from the start of changing the setting of the roll speed to the point where the welding point C reaches the setting change target stand is from the roll gap / roll speed calculating device 32 to the roll gap setting devices 11 to 15 and the roll speed setting devices 21 to 25. Is entered. These inputs are performed in accordance with the timing instruction signal from the setting change timing instruction device 34.

The setting change timing instruction device 34 tracks the welding point C of the material A to be rolled and the material B to be rolled, and rolls the timing instruction signal immediately before reaching the first to fifth rolling stands # 1 to # 5. It is applied to the gap setting devices 11 to 15 and the roll speed setting devices 21 to 25. In accordance with the input of the timing instruction signal, the data from the roll gap / roll speed calculation device 32 calculated as described above is given to the roll gap setting devices 11 to 15 and the roll speed setting devices 21 to 25 to be rolled. Material B is rolled.

Next, the calculation process of the time τ _opt will be specifically described. The change of the running speed of the roll speed of the i-th rolling stand #i is performed between the inlet of the i-th rolling stand #i and the outlet of the i-th rolling stand #i given by the following formula (7) before the start of the changing of the running distance. Mass flow constant rule and v _i-1 h _i-1 ^A = v _i h _i ^A (7) where, v _i : Departure speed h _i ^A of the i-th rolling stand before the start of changing the running setting: pre-rolled It is performed so that the constant mass flow law between the i-th rolling stand inlet and the i-th rolling stand outlet, which is given by the following equation (8), is satisfied after the setting change of the steady plate thickness between the i-th rolling stand exit side of the material is completed. . v _{i -1} ′ h _{i -1} ^B = v _i ′ h _i ^B (8) where v _i ′: i-th rolling stand exit side plate speed after completion of change in running setting h _i ^B : trailing rolled material Steady plate thickness at the i-th rolling stand exit side

The roll gap of the i-th rolling stand #i is expressed by the following equation (9) based on the gauge meter equation.
Only S _i is changed. ΔS _i = h _i ^B −h _i ^A − (P _i ^B −P _i ^A ) / M _i (9) where P _i ^A is the i-th rolling stand steady rolling load P _i ^B of the preceding rolled material Steady rolling load M _{i of} rolling material of rolling material: Mill rigidity coefficient of i-th rolling stand

Running distance when changing such running distance settings
The setting change start timing is determined as follows. First of all,
Welding of the preceding rolled material A and the following rolled material B as shown in Fig.
The point C coincides with the timing of reaching the i-th rolling stand.
The roll gap and roll speed of the i-th rolling stand
Input side tension stress change when the setting change of
Momentum Δσ_bi ^A, Output tension stress variation Δσ_fi ^AAnd in FIG.
As shown, the welding points of the preceding rolled material A and the following rolled material B
Matches the timing when C reaches the i-th rolling stand #i
If you start changing the running settings as
Side tension stress variation Δσ_bi ^B, Output tension stress variation Δσ_fi
^BAnd ask.

In the former case, immediately before the welding point C reaches the i-th rolling stand, the inlet of the i-th rolling stand and the i-th rolling stand.
The constant law of mass flow with the exit of the rolling stand is given by equation (10). v _i-1 ′ h _i-1 ^AP = v _i ′ h _i ^AP (10) where h _i ^AP is the thickness of the i-th rolling stand exit side plate just before the welding point C reaches the i-th rolling stand h ₀ ^AP = h ₀ ^A … (11)

From equations (8), (10), and (11), the outlet plate thickness of the i-th rolling stand immediately before the welding point C reaches the i-th rolling stand is given by equation (12). h _i ^AP = h _i h ₀ ^A / h ₀ ^B (12) The i-th rolling stand plate thickness variation Δh _i seen from before the start of changing the running setting is given by equation (13). Δh _i ^A = h _i ^AP −h _i ^A = h _i ^B h ₀ ^A / h ₀ ^B −h _i ^A (13)

The rolling load fluctuation amount ΔP _i ^A seen from before the start of changing the running setting is given by the equation (14) by applying the equations (3) and (7) to the gauge meter equation. ^{_{+ ΔP i A = P i B}} -P i A (h 0 A / h 0 B -1) h i B M i ... (14)

Therefore, the inlet side tension stress variation amount Δσ _bi ^A and the outlet side tension stress variation amount Δσ _fi ^A of the i-th rolling stand are the rolling load formula before the start of the change of running setting and the welding point C is the i-th rolling stand. Just before reaching the rolling load equation as shown in equations (15) and (16),

[0032]

[Equation 1]

The advanced rate equations given by the equations (17) and (18) at each time point and

[0034]

[Equation 2]

From equations (19) and (20),

[0036]

[Equation 3]

[0037]

[Equation 4]

[0038]

[Equation 5]

[0039]

[Equation 6]

On the other hand, in the latter case, immediately after the welding point C reaches the i-th rolling stand, the constant mass flow rule between the i-th rolling stand inlet and the i-th rolling stand outlet given by the equation (21) and v _{i- From} 1h _i-1 ^BP = v _i h _i ^BP (21) and (7), the i-th rolling stand delivery side plate thickness h _i ^BP is given by (22). h _i ^BP = h _i ^A h ₀ ^B / h ₀ ^A (22)

The end timing of changing the running setting is set to the welding point C.
Is calculated in the same manner as when the running distance setting of the i-th rolling stand #i is changed so as to coincide with the timing of reaching the i-th rolling stand # 1. The inlet side tension stress fluctuation amount Δσ _bi ^B and the outlet side tension stress fluctuation amount Δσ _fi ^B are given by equations (23) and (24).

[0042]

[Equation 7]

[0043]

[Equation 8]

[0044]

[Equation 9]

[0045]

[Equation 10]

When the welding point C reaches the i-th rolling stand #i within the time range from the start of changing the running distance setting of the i-th rolling stand #i to the completion of changing the running distance setting, the i-th rolling stand The stand-side tension stress and the stand-side tension stress are as shown in FIG.

In FIG. 4, the horizontal axis represents time, and the vertical axis represents tensile stress.
, And the broken line l_b ^A, L_f ^AIs shown in FIG.
If the running distance setting is changed as described above, the broken line l_b ^B，
l_f ^BShows the case of changing the running settings as shown in Fig. 3.
Prediction of tensile stress for the preceding rolled material A and the following rolled material B
The transfer is shown respectively. Rolling at i-th stand #i
As the process progresses, the tension on the inlet and outlet sides of the i-th stand #i
The stress is the entrance side tension stress σ of the preceding rolled material A._bi ^A, Departure
Force stress σ_fi ^AFrom (in the figure), σ_bi ^A+ Δσ_bi ^A, Σ_fi
^A+ Δσ_fi ^ACurve l towards_b ^A, L_f ^AMove up
To reach the point in the figure. Welding point C is the i-th rolling stand
At the moment when it passes, the rolled material is pressed from the preceding rolled material A to the trailing pressure.
By changing to rolled material B, from the point in the figure,
Entry-side tension stress σ of B_bi ^B, Output side tension stress σ_fi ^BAnd σ_bi ^B
+ Δσ_bi ^B, Σ_fi ^B+ Δσ_fi ^BCurve l connecting_b ^B, L_f
^BMomentarily fluctuates to the point in the figure above, and the change of running settings is completed.
At the timing_bi ^B, Σ_fi ^BReach (in the figure).

(19), (20), (23), (24)
As can be seen from the equation, in general, Δσ _bi ^A , Δσ _bi ^B and σ _fi ^A ,
It does not match Δσ _fi ^B, and the curves l _b ^A and l _b ^B and l _f ^A and l _f ^B are not parallel. Therefore, by selecting the passage timing of the welding point C, in other words, the setting change start timing τ _opt , so that the welding point C reaches the i-th rolling stand #i at the timing when the distance between the two curves is closest,
The welding point C passes through the i-th rolling stand #i and the
It is possible to suppress the fluctuation in tension due to the change in dimensional specifications .

Actually, setting of roll gap and roll speed
Rolling strip with welding point C changed after starting the change
Time to pass tan_optIf is set to 0,
As shown in Fig. 3, rolling settings can be changed by rolling the succeeding rolled material B.
It will be done only inside, τ _optThe roll gap
When the constant change time T is matched, as shown in FIG.
Completion of change of running setting during rolling of preceding rolling material A
become. τ_optIs the welding point C passing through the rolling stand
Timing comes within the roll gap setting change time
Thus, in other words, it is determined that the following expression is satisfied. 0 ≦ τ_opt≤T However, T: Roll gap setting change time τ_optSetting range of 0 ≦ τ_optSetting change time as ≤T
Of the longest roll gap setting time
As a result, the curve l shown in FIG._b ^AAnd l_b ^B, L_f ^AAnd l
_f ^BWelding the rolling stand when the distance between them becomes the shortest
It is possible that the timing can be set so that point C can pass.
Because it grows.

Next, the comparison test results of the method of the present invention and the conventional method will be described. Using a tandem mill consisting of 5 stands as shown in FIG. 1, a plate width of 899 mm and a plate thickness of 5.0
mm pre-rolled material, plate width 885mm, plate thickness 3.5m
As for the trailing rolled material of m, the leading rolled material was rolled to 2.3 mm and the trailing rolled material was rolled to 0.6 mm. FIG. 5 shows fluctuations of the inlet side tension and the outlet side tension of the third rolling stand # 3 during and before and after the change of the running distance setting when rolling by the method of the present invention.

FIG. 6 shows a case where rolling is performed by the conventional method in which the roll gap setting is changed so that the welding point C of both rolled materials reaches the rolling stand in half the time required for changing the roll gap setting. Third rolling stand #
3 shows fluctuations in the tension on the inlet side and the tension on the outlet side of the third rolling stand # 3 during the change in the running distance setting of No. 3. As is clear from comparison between FIGS. 5 and 6, it can be seen that when the method of the present invention is used, the fluctuation in tension during rolling of the preceding rolled material A and the fluctuation in tension when passing through the welding point C are suppressed.

In the above embodiment, the roll gap,
Rolling speed setting change time from 1st to 5th rolling stand #
Although a case has been described in which all of 1 to # 5 are matched with T, the roll gap and roll speed setting change time in each stand may be different.

[0053]

As described above, in the first invention,
The time difference between the roll gap and roll speed setting change start timing and the welding point arrival time at the rolling stand is determined and controlled by the material and size of the material to be rolled, and tension fluctuations during the running setting change It is possible to realize a stable rolling operation without breaking the rolled material, and it is impossible with the conventional method because the tension fluctuation becomes large, and it is not possible to perform the rolling operation between rolled materials with significantly different strip thickness and strip width. It is also possible to change the running settings.

In the second aspect of the invention, the time difference between the roll gap / roll speed setting change start timing and the timing at which the welding point reaches the rolling stand is specified to be less than the roll gap setting change time T. Therefore, the welding point passes within the running time setting change time, the setting can be changed at an optimum timing, and the fluctuation in tension of the material to be rolled can be effectively suppressed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a tandem mill consisting of five stands to which a rolling mill setting change control method of the present invention is applied.

FIG. 2 is a graph showing a change timing between running settings and a change in plate thickness and tension.

FIG. 3 is a graph showing a change timing between running settings and a change in plate thickness and tension.

FIG. 4 is a graph showing changes in plate thickness and tension during changing running settings.

FIG. 5 is a graph showing tension fluctuations when the running distance setting is changed by the method of the present invention.

FIG. 6 is a graph showing tension fluctuations when a running distance setting is changed by a conventional method.

[Explanation of symbols]

# 1 to # 5 rolling stand 11-15 Roll gap setting device 21-25 Roll speed setting device 31 coil information transmission device 32 roll gap / roll speed calculator 33 Change time calculation device 34 Setting change timing instruction device

Claims (2)

(57) [Claims] 1. A preceding rolling material and a following rolling material welded thereto are continuously rolled, and a welding point of the preceding rolling material and a following rolling material passes through a predetermined rolling stand. At the same time as or prior to this, in the method of changing the rolling gap setting and rolling speed setting of the rolling stand, the welding point is set from the time when the rolling gap and rolling speed setting changes are started. The time required to pass the specified rolling stand where the setting change was started , and the rolling load and the advance rate were calculated.
Required material for the preceding rolled material, trailing rolled material, plate thickness and
A method for changing the running distance setting of a rolling mill, which is characterized in that it is determined based on the sheet width and strip width . 2. The time τ _opt from the start of the setting change of the roll gap and the roll speed until the welding point passes a predetermined rolling stand where the setting change is started, 0 ≤ τ _opt ≤ T, where T: roll gap 2. The method for changing running distance settings of a rolling mill according to claim 1, wherein the setting time is set.