JPH0899104A - Method for determining pass schedule of continuous rolling mill - Google Patents

Abstract

PURPOSE: To easily and surely determine an apropreate pass schedule for utilizing equipment performance at the maximum. CONSTITUTION: In a hot finishing mill for rolling a sheet bar after rough rolling, constraint conditions and other rolling conditions from the viewpoint of equipment and operation and the target thickness, width, rolling temp. and rolling speed on the outlet side of the 7th (final) stand are set to each stand (step 110), the retroactive calculation of the max. thickness and rolling temp. which are rolled in each stand in the range of the constraint conditions is successively executed using each target value from the final stand according to the steps 112-134. The max. thickness of the sheet bar which can be rolled in the 1st stand is determined (step 136) and, defining the max. thickness and rolling temp. which are attained in every stand as a guide line, actual pass schedule is determined in that range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of determining a pass schedule of a continuous rolling mill, and particularly to a continuous process suitable for determining a pass schedule for rolling a sheet bar after rough rolling in a hot rolling process. The present invention relates to a pass schedule determination method for a rolling mill.

[0002]

2. Description of the Related Art Generally, as a method of determining a pass schedule when rolling with a tandem rolling mill including finish rolling in a hot rolling process, there is, for example, "Theory and Practice of Sheet Rolling" edited by The Iron and Steel Institute of Japan. As described on page 138 of the above, the consumed rolling power ratio (load distribution ratio) set for each stand is regulated, and the final stand exit side plate thickness becomes the target plate thickness so that A method of determining the roll gap and the roll speed is used.

This conventional path schedule determination method is
For example, when applying to finish rolling for rolling various rolled materials with different steel types and sizes, and when determining the pass schedule, consider the rolling factor for each rolled material and allocate the above load to each stand. It is necessary to set an appropriate value for the ratio.

[0004]

However, when applying the above-mentioned conventional pass schedule determination method, since the operator determines the set value of the load distribution ratio for each stand based on his experience, various rolled materials are to be rolled. It is extremely difficult to determine an appropriate pass schedule set value that can maximize the equipment performance for each material and prevent the occurrence of problems such as rough skin of the roll. There was a problem that it could occur.

Also, when rolling is performed with a continuous rolling mill while accelerating and decelerating, similarly, a target strip thickness, strip width, rolling temperature, and rolling speed are obtained within the capability range of the facility over the entire length of the strip material. There is a problem that it is difficult to determine an appropriate set value of the pass schedule that can achieve the above, and this may hinder the operation.

The present invention has been made to solve the above-mentioned conventional problems, and makes it possible to make maximum use of facility performance without relying on experience and to easily and surely determine an appropriate path schedule. A first object is to provide a method of determining a pass schedule of a continuous rolling mill, which is capable of performing the above.

The present invention is also capable of maximizing equipment performance without relying on experience when rolling while accelerating or decelerating, that is, in accordance with a speed pattern accompanied by acceleration and deceleration.
A second object is to provide a pass schedule determination method for a continuous rolling mill capable of easily and reliably determining a common and appropriate pass schedule over the entire length of the material to be rolled.

[0008]

According to a first aspect of the present invention, there is provided a method for determining a pass schedule of a continuous rolling mill when rolling a target material to be rolled on the delivery side of a final stand by the continuous rolling mill, wherein By setting constraints on equipment and operation, and using the target strip thickness, strip width, rolling temperature, and rolling speed on the exit side of the final stand, the maximum rolling amount at each stand within the set constraints above The first problem is solved by sequentially calculating the plate thickness from the last stand and determining the pass schedule using the maximum rollable plate thickness obtained for each stand as a guideline.

According to a second aspect of the present invention, there is provided a method of determining a pass schedule of a continuous rolling mill when rolling a target material to be rolled on the delivery side of a final stand according to a speed pattern accompanied by acceleration and deceleration by the continuous rolling mill, Equipment for each stand
By setting operational constraints, the target strip thickness, strip width, rolling temperature, and rolling point for each judgment point of the material to be rolled that correspond to multiple judgment points on the speed pattern are rolled. Using the speed, the maximum sheet thickness that can be rolled at each stand within the range of the above set constraint conditions is calculated retroactively from the last stand, and rolling is possible for each stand obtained at each judgment position of the material to be rolled. The second problem is solved by determining a common pass schedule over the entire length of the material to be rolled using the minimum value of the maximum plate thickness as a guideline.

According to a third aspect of the present invention, in the pass schedule determination method for the continuous rolling mill according to the first or second aspect, the constraint conditions set for each stand are rolling load, rolling torque, rotational driving force, reduction ratio and It is the linear pressure.

According to a fourth aspect of the present invention, in the pass schedule determination method for the continuous rolling mill according to the first aspect, at least the rolling temperature at the entrance side of the first stand is calculated, and the rolling temperature is also used as a guideline. .

According to a fifth aspect of the present invention, in the pass schedule determining method for the continuous rolling mill according to the second aspect, the necessary minimum rolling temperature on the entrance side of the first stand is calculated for each determination position of the material to be rolled, and The air-cooling temperature, which is cooled until the judgment position reaches the first stand, is added to the above-mentioned rolling temperature calculated for each judgment position to obtain the minimum rolling material required at the same time point before rolling. The temperature is calculated and the maximum value is used as a guideline.

[0013]

According to the first aspect of the invention, constraint conditions are set for each stand from the standpoint of facility and operational performance, and the target plate thickness and plate width on the outlet side of the final stand are set.
Using the rolling temperature and rolling speed, the maximum plate thickness that satisfies the constraint conditions set for each stand is calculated from the first stand to the first plate thickness.
By performing retroactive calculation up to the stand, the limit pass schedule that can roll the maximum strip thickness that satisfies each constraint condition is decided.Therefore, it is only necessary to perform the actual operation within that range. It becomes possible to determine the setting reference value for the pass schedule.

Therefore, by determining the actual pass schedule by using the maximum plate thickness obtained for each stand as a guideline, various rolled materials having different steel grades and sizes can be used within a range not exceeding the performance of each stand. On the other hand, it is possible to determine an appropriate pass schedule that is consistent among rolling factors such as sheet thickness, sheet width, rolling temperature and rolling speed.

Further, when deciding an appropriate pass squeeze juice for various materials to be rolled, it is possible to eliminate uncertain determinants due to the experience of the operator, so that it is possible to reduce the maintenance load. Becomes

Further, even if the rolling conditions are changed,
By simply changing the constraint conditions for each stand, it is possible to determine an appropriate pass schedule for various materials to be rolled while matching each rolling factor, and it is possible to easily perform operations without problems. Is possible.

According to the second aspect of the present invention, similarly to the first aspect of the present invention described above, facility / operating constraint conditions are set for each stand and a plurality of determination points on the speed pattern are handled. Regarding the judgment position of the material to be rolled, using the target plate thickness on the exit side of the final stand, plate width, rolling temperature and rolling speed at each judgment point, it is possible to roll at each stand within the range of the above-mentioned constraint conditions set. The maximum plate thickness is calculated retroactively from the last stand, and the minimum value of the maximum plate thickness for each stand obtained at each judgment position of the rolled material is used as a guideline for the entire length of the rolled material. Since a common pass schedule is determined, even when rolling with acceleration and deceleration, there is consistency between rolling factors such as different rolling speeds, and a common and appropriate pass schedule for the entire length of the material to be rolled. And it is possible to determine for example automatically.

Further, since the thickest pass schedule that satisfies the constraint condition can be determined over the entire length of the material to be rolled, finish rolling can be performed by using the limit capacity of the equipment without hindering the operation. If the operation is carried out within this range, there will be no equipment failure over the entire length of the rolled material, and the limit of the set value can be easily known. In addition, as the determination point, a change point of the rolling state (for example, rolling speed) is selected. In Examples described later, (A) to (E) were selected as one example.

Further, in the invention of claim 1 or 2, when the constraint conditions set for each stand are rolling load, rolling torque, rotational driving force, rolling reduction and linear pressure, no problem occurs. The pass schedule can be reliably determined.

Further, in the invention of claim 1, when the minimum required rolling temperature (minimum required sheet temperature) at least on the entrance side of the first stand is calculated and the rolling temperature is also used as a guideline, The maximum sheet thickness that can be rolled at each stand can be determined, and the minimum temperature of the material to be rolled at the first stand necessary for rolling to that sheet thickness can also be determined, so a more appropriate pass schedule can be determined. It becomes possible.

In the invention of claim 2, further, the minimum required rolling temperature on the entrance side of the first stand is calculated for each judgment position of the material to be rolled, and cooling is performed until each judgment position reaches the first stand. The air-cooling temperature is added to each of the above-mentioned rolling temperatures calculated for each judgment position to obtain the minimum temperature of the material to be rolled required at the same time point before rolling, and the maximum value among them is also used as a guideline. In this case, the maximum pass schedule for rolling while accelerating and decelerating, and the minimum heating temperature required for the material to be rolled before the rolling can be determined.

[0022]

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

FIG. 1 is an explanatory view showing a schematic structure of a hot finish rolling mill comprising 7 stands to which the pass schedule determination method of the first embodiment according to the invention of claim 1 is applied, and FIG. It is a flowchart which shows the procedure which determines the guideline of a pass schedule by applying the method of an Example.

In this embodiment, the constraint conditions shown in Table 1 are set for the first to seventh stands indicated by F1 to F7 in the figure, and the target plate thickness shown in Table 2 on the exit side of the seventh stand. A method for determining a pass schedule for hot finish rolling in the case of rolling a strip (rolling material) having a strip width and a rolling temperature will be described. Here, since it is a general rolled material, it is considered that the method of the present invention is suitable for comparison with the conventional method.
The material to be rolled shown in was adopted.

[0025]

[Table 1]

[0026]

[Table 2]

In Table 1 above, for each of the first stand F1 to the seventh stand F7, set as constraint conditions on equipment, (2) rolling load, (4) torque and (5) motor power ( (1) Reduction ratio and (3) Linear pressure (rolling load per unit width), which are set as operating conditions to prevent problems such as roughening of the roll, along with the respective maximum values that regulate the rotational driving force). ) Is shown for each maximum value. These values are determined in consideration of prevention of rough skin of the roll of each stand and current limitation. The power limit value in the (4) Torque column is the value of (5), and the base speed is the rated speed of the motor.

In the present embodiment, the maximum strip thickness and rolling temperature that can be rolled at each stand are calculated sequentially from the seventh stand to the first stand in sequence according to the flowchart of FIG.

First, each constraint condition shown in Table 1 and other rolling conditions are set for each stand, and
The target strip thickness, strip width and rolling temperature (FDT) on the exit side of the seventh stand (final stand) shown in Table 2 and the target rolling speed on the exit side of the stand are set (step 110). In this embodiment, the target rolling speed is set to 640 mpm. Here, other rolling conditions include work roll diameters, friction coefficients, stand distances, s / c patterns, components of the material to be rolled, which are fixed values. It should be noted that the s / c pattern means the O of the cooling water jetting device provided between the stands in order to bring the rolled material to the target temperature.
It is an N / OFF pattern.

Next, the average plate temperature T of the rolled material on the delivery side of the seventh stand is calculated using the following equation (1) (step 112). Here, the surface temperature Ts is the target FDT (finishing mill exit temperature) shown in Table 2.

T = α · Ts + β · h + γ (1) Ts: Surface temperature h: Outlet plate thickness α, β, γ: Constant

Next, the plate thickness H on the 7th stand entry side is assumed within the allowable rolling reduction shown in Table 1 above (step 11).
4) Then, the entry side plate thickness is applied to the following equation (2) to calculate the deformation resistance Km (step 116). At that time, the first rolling cumulative strain ε'is calculated as 0.

[0033]

[Equation 1]

The rolling strain rate in the above equation (2) is the amount of strain per unit time during rolling.

After the step 116, the rolling load P required to roll the rolled material having the above plate thickness (assumed value) on the seventh stand is calculated using the following equation (3), and the target rolling speed is calculated. And the roll peripheral speed is used to calculate the advanced rate (step 118).

P = W · Km · Qp · ld (3) Qp = Qp (μ, H, R, R ′, Km, t) W: Strip width Qp: Rolling force function ld: Contact arc length μ: Friction Coefficient H: Inlet side plate thickness r: Reduction ratio R ': Flat work roll radius t: Tension In addition, the preset value is used as the tension t here.

Next, the rolling temperature on the entry side of the seventh stand is calculated (step 120). This rolling temperature is obtained by calculating the rolling temperature change amount ΔTa when rolling on the 7th stand by the following equation (4), and subtracting this change amount ΔTa from the outlet temperature (FDT) to calculate back. You can

ΔTa = A · ΔTf + B · ΔTw + C · ΔTc (4) ΔTf: Friction heat generation amount ΔTw: Processing heat generation amount ΔTc: Heat transfer amount to work roll A, B, C: Constant

Then, it is judged whether or not the deformation resistance Km has converged (step 122). Here, it is assumed that the calculated value of this time has converged if it is within ± 0.1% of the calculated result of the previous time.

If No at step 122 (No at the first time), the inlet temperature calculated at step 120 is used (step 124), and the inlet temperature and the outlet temperature calculated at step 112 are used. After obtaining the average value of the temperature, the process returns to the step 116, and the average value is set as T and is substituted into the equation (2) to recalculate the deformation resistance Km.

If Yes in step 122, it is checked whether the calculated values of rolling load, linear pressure, rolling torque, and motor power are within the range of the constraint conditions for the material to be rolled having the plate thickness assumed in step 114. (Step 12
6). At that time, the rolling torque G is calculated by the following equation (5).

[0042] G = W · R · {( H-h) · Km · Q G + H · tb-h · tf} ... (5) Q G = Q G (μ, H, r, R ', Km, t ) W: strip width R: work roll radius H: thickness at entrance side h: exit side thickness Km: deformation resistance Q _G: torque function tb: rear tension tf: forward tension mu: friction coefficient r: reduction ratio R ': flat WR Radius Here, as each tension of tb, tf, and t 3, a set value prepared in advance is used like the tension t described above.

If the result of the check in step 126 is NG, the plate thickness is changed (step 128), the process returns to step 114, and the processes up to step 126 are performed again. If the check result is OK, one step upstream To the sixth stand F6, the above-described processing of steps 114 to 128 is executed as in the case of the seventh stand, and the same calculation processing is executed by sequentially tracing back to the fifth stand F5 to the first stand F1 ( Step 130). When going to the stand one step upstream, the rolling temperature at the exit side is set in consideration of the inter-stand temperature decrease amount ΔT calculated by the following equation (6). The transfer time Δt is set based on the distance between stands.

ΔT = (λ · To + ζ · Δt) / H (6) To: initial temperature (upstream stand outlet temperature) Δt: transfer time H: plate thickness λ, ζ: constant

In step 130, all stands (7th
~ First stand) Step 114 ~ Step 1
After performing the processes up to 28, it is determined whether or not the plate thickness (sheet bar thickness) on the entrance side of the first stand has converged as compared with the previous process (step 132). Specifically, if the calculated value of this time is within ± 0.1% of the calculated result of the previous time, it is assumed that the value has converged. Here, in order to compare with the previous processing result, the first processing is always No.

If No in step 132, the cumulative strain ε'is calculated from the plate thickness assumed in each stand (step 134), and then the process returns to step 114 and the processes up to step 132 are executed again to converge. Repeat until you do. As described above, in this embodiment, if the sheet bar thickness is not determined, the cumulative strain ε'when the deformation resistance Km is calculated.
Therefore, convergence calculation for the seed bar thickness is performed.

If Yes in the above step 132, the converged value is determined as the maximum sheet bar thickness (step 136),
Moreover, the rolling temperature on the entry side of the first stand is determined.
Further, the maximum sheet thickness on each stand-entry side and the rolling temperature calculated in the process of determining the maximum sheet bar thickness are determined as the allowable values of the pass schedule.

According to this embodiment described above, in order to achieve the target plate thickness, rolling temperature, etc. on the exit side of the seventh stand while satisfying the constraint conditions set for each stand, Since the maximum allowable sheet thickness can be determined and the rolling temperature can be determined, it is possible to determine the maximum value and the minimum required rolling temperature for the sheet bar thickness after rough rolling that can be rolled by the first stand. Table 3 shows the pass schedule based on the calculation result, and Table 4 shows the rolling temperature at the entrance side of the first stand.

[0049]

[Table 3]

[0050]

[Table 4]

Table 3 above shows the thickness of the sheet bar rolled by the first stand as the pass schedule, and the plate thickness at each exit side of the first stand to the seventh stand.
In the upper part of Table 3, the maximum sheet bar thickness that can be finish-rolled and the maximum value of the delivery side plate thickness corresponding to the maximum processing amount of each stand when the sheet bar is rolled are calculated, which are calculated according to the present embodiment. The lower part shows the conventional pass schedule used when rolling the material to be rolled shown in Table 2 above.

From the results of Tables 3 and 4 described above, the maximum value of the pass schedule calculated by the present invention is thicker, although the conventional pass schedule is set in consideration of the actual operation. I understand.

Therefore, according to the present invention, it is possible to easily know the limit of the proper pass schedule which does not cause any trouble without relying on the experience of the operator, and therefore, the limit of the plate thickness shown in Table 3 above is allowable. As a value, it is possible to properly determine the actual pass schedule within that range. Further, as is clear from Table 4, according to this embodiment,
It is possible to significantly reduce the rolling temperature of the sheet bar rolled by the first stand.

As described above in detail, according to the present embodiment, the restriction conditions for equipment and operation are set for each rolling stand, and the target plate thickness, plate width, rolling speed, From the rolling temperature, it is possible to determine the maximum sheet bar thickness after rough rolling that satisfies the above constraint conditions, the pass schedule of each stand (exit plate thickness), and the minimum rolling temperature required for the sheet bar. Therefore, it is possible to easily know the limit of an appropriate pass schedule that does not cause a defect for various rolled materials having different steel types and sizes.

Therefore, the thickest pass schedule (maximum allowable plate thickness) calculated according to the present embodiment is used as a guideline to set the pass schedule for actual operation within that range, thereby making it wider than the conventional range. It is possible to easily and surely determine a highly reliable pass schedule.

The actual pass schedule is shown in Table 3 above.
Since it is set to a value smaller than the delivery side plate thickness shown in, it is possible to further reduce the amount of temperature drop of the rolled material that occurs during operation from the above calculated value, so that the target temperature is achieved on the delivery side of the seventh stand. It is possible to further lower the extraction temperature from the heating furnace required by the above, and it is possible to significantly improve the fuel consumption rate of the heating furnace.

Next, the path schedule determination method of the second embodiment according to the invention of claim 2 will be described. The present embodiment is a pass schedule determination method when rolling according to a speed pattern accompanied by acceleration / deceleration.

In the present embodiment, a common pass schedule for the entire length of the material to be rolled is determined when hot finish rolling is performed on the sheet bar after rough rolling according to the rolling speed pattern shown in FIG. , Determine the minimum finishing entry temperature (FET) required at that time.

Similar to the first embodiment, the number of stands of the finish rolling mill to be used is 7, the facility and operation constraints are the conditions shown in Table 1 above, and the delivery side target value is The values are the same as those shown in Table 2 above.

In FIG. 3, the horizontal axis represents elapsed time, and the vertical axis represents rolling speed.
It shows the speed pattern from the biting of the stand F1 to the trailing edge of the final stand by Fx OFF. In FIG. 3, the rolling speed (outgoing speed) on the exit side of the final stand is shown after the time Fx ON when the tip of the material to be rolled is bitten by the final stand (seventh stand). The meanings of the symbols shown in FIG. 3 are as follows.

F1ON: When the front end F1 stand is bitten,
Fm ON: Tip Fm Stand biting, Fx ON: Tip finishing finishing biting the last stand, CLON tip coiler winding, Fm OFF: Deceleration stand OFF (Fm stand tail end plate missing) (Deceleration start before F1 OFF) TM _F1 : Acceleration / deceleration time in the mill, TM _HO : Table acceleration / deceleration start timing, TM _H1 : Table acceleration / deceleration that performs acceleration / deceleration in consideration of the stripability on the table, TM _CO : Coiler acceleration start timing V _THR : Threading speed, V _TOP : Top speed, V
_FX : Finish final stand biting speed, V _F1 : Tip F1 stand biting speed, V _FXOFF : Finishing final stand trailing edge slipping speed α _F : Mill acceleration / deceleration, α _H1 : Table acceleration / deceleration, α _C : Coiler acceleration Deceleration acceleration, α _D : tail deceleration rate

Further, (A) to (E) shown by being superimposed on the speed pattern of FIG. 3 indicate whether or not the constraint condition is satisfied for the material to be rolled (sheet bar) rolled according to this speed pattern. The determination points (A) to (E) are for determining whether or not the determination positions (A) to (E) indicated by the same symbols on the seat bar S in FIG. 4 pass through the seventh stand. It corresponds to the timing to do.

In this embodiment, the rolling speed, the lower limit speed, etc. are set to the specific values shown in Table 5 below.

[0064]

[Table 5]

As a first step, for each of the determination positions (A) to (E) of the seat bar S shown in FIG. 4, the target finishing temperature FDT together with the respective finishing speeds V _{7A to} V _7E. , The same output side plate thickness h ₇ is given, and in accordance with the procedure shown in the flow chart of FIG. 2 as in the case of the first embodiment, the maximum of satisfying the constraint condition of each stand in order from the determination position (A) Obtain the sheet bar thickness and finally
As conceptually shown in the lower part of, the finish entry side for each determination position (first stand entry side) thickness H _A to H _E, finish entry side temperature FET _A ~FET _E, and rolling speed V _0A ~ Calculate V _0E .

In Table 6, the maximum plate thickness on the stand-out side of each stand obtained for each of the judgment positions (A) to (E) by the above-described calculation of the first stage and the sheet bar thickness (the maximum thickness on the first stand-entry side) Sheet thickness) and the target rolling speed on the delivery side of the seventh stand.

[0067]

[Table 6]

In this embodiment, each of the judgment positions (A) to (E).
And determines the calculated ones thinnest among pass schedule shown in Table 6 as a common pass schedule over the entire length for the maximum possible rolled sheet the minimum value in the sheet bar thickness H _A to H _E Determine the bar thickness H ^* .

Further, in the present embodiment, as the second step, the required minimum rolling temperature on the entrance side of the first stand is calculated for each judgment position of the material to be rolled, and each judgment position reaches the first stand. Calculate the minimum temperature of the material to be rolled required at the same time before rolling by adding the air-cooling temperature cooled up to this point to the rolling temperature at each judgment position, and use the maximum value of these as a guideline. I do.

That is, when each of the determination positions (A) to (E) reaches the first stand F1, the temperature at each position is adjusted to the above-mentioned first temperature.
The finish entry side temperature FET _A ~FET _E of each determination position calculated in step (A) ~ (E), in order to match, the lowest temperature at each determination position is needed at the same time before rolling Ask. For example, as conceptually shown in FIG. 5, when the point (A) of the seat bar S is bitten by the first stand, the temperatures at the points (B) to (E) are the first temperature. Each of the air cooling temperatures ΔT _{B to} ΔT _E obtained by the product of the air cooling time t _B to t _E before being caught in the stand and the cooling rate by air cooling, and the first
Finishing side temperature FET _{B to} FET at each point obtained in the step
Calculate as the sum of _E. Obtained by this calculation (B) ~
(E) Required minimum temperature of each point FET _B + ΔT _B ~ FET
The highest temperature among _E + ΔT _E and the temperature FET _{A at} the point (A) is set as a common finishing-side temperature FET ^* over the entire length.

Table 7 shows the temperature at point (A) when the tip is bitten into the first stand F1 and the minimum temperature required at each point (B) to (E). , Common finishing temperature FET ^* is shown.

[0072]

[Table 7]

According to the conventional method, the maximum sheet bar thickness, the pass schedule, and the finishing side temperature (rolling temperature before finishing rolling), which are common guidelines for the entire length of the sheet bar, calculated by the above-described embodiment, are used. The obtained sheet bar thickness, pass schedule, and finishing entry side temperature in actual operation are compared and shown in Tables 8 and 9.

[0074]

[Table 8]

[0075]

[Table 9]

From the results of Tables 8 and 9 above, it can be seen that the pass schedule calculated by the method of the present embodiment is thicker and the finishing side temperature is lower than that of the conventional method. Therefore, according to the present embodiment, even when one sheet bar is rolled at different speeds, problems such as roll roughening do not occur in the operation within the limit of the capacity of the equipment, and the entire length of the rolled material can be obtained. A common pass schedule can be easily calculated, and when determining an appropriate pass schedule, the maintenance load can be reduced and human insufficiency can be compensated. Since the set value of the low rolling material can be calculated, the temperature of the heating furnace for heating the sheet bar before finish rolling can be lowered, and the fuel can be reduced.

As described above in detail, according to the present embodiment, each finishing stand is provided with a constraint condition in terms of equipment and operation, and the target plate thickness, plate width, rolling temperature, and load on the exit side of the final finishing stand are set. From the rolling speed to decelerate, it is possible to determine the common thickest sheet bar thickness over the entire length of the material to be rolled that satisfies the given constraint conditions, the pass schedule in finishing rolling and the rolling temperature before finishing rolling, It is possible to determine a common and appropriate pass schedule for rolling materials of various steel grades and sizes with no problems.

Further, according to the present embodiment, since the thickest pass schedule and the lowest rolling temperature can be determined, it is possible to reduce the temperature drop amount of the material to be rolled during the operation.
Further, since the extraction temperature of the material to be rolled from the heating furnace necessary for achieving the target temperature can be lowered, there is also an advantage that the fuel consumption rate of the heating furnace can be improved.

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

For example, in the above embodiment, the maximum value of the sheet bar thickness after rough rolling that can be rolled by the first stand, the pass schedule (maximum sheet thickness) at each stand, and the rolling temperature at the first stand are determined. However, the present invention is not limited to this, and when determining the actual pass schedule within the range of the maximum plate thickness of each stand calculated as a guideline according to the present invention, the sheet bar thickness and each It is also possible to fix the stand outlet side plate thickness and calculate the minimum rolling temperature on the first stand inlet side required to achieve the target temperature on the final stand outlet side.

When the material to be rolled is rolled while accelerating and decelerating, in the invention of claim 1, the fastest speed after completion of acceleration is given as the rolling speed on the delivery side of the final stand. It is also possible to calculate a pass schedule that can make the thickest and use it as a common guideline over the entire length.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the hot finish rolling mill consisting of 7 stands has been explained, but the number of stands is not limited to this, and is not necessarily limited to the hot rolling mill, and the It can also be applied to hot rolling.

[0083]

As described above, according to the invention of claim 1, the facility performance can be maximized without depending on the experience of the operator, and an appropriate path schedule can be easily and surely determined. Will be possible.

According to the second aspect of the present invention, even when rolling is performed while accelerating and decelerating, among rolling factors such as plate thickness, plate width, rolling temperature, and accelerating and decelerating rolling speed over the entire length of the material to be rolled. Since it is possible to determine a pass schedule that is consistent with, it is possible to determine a common and appropriate pass schedule over the entire length of the material to be rolled.

According to the invention of claim 3, claim 1 or 2
In the method of determining a pass schedule described in (1), it is possible to reliably determine a pass schedule that does not cause a problem.

According to the invention of claim 4, an appropriate rolling temperature can be determined in addition to the pass schedule.

According to the invention of claim 5, in the pass schedule determination method of claim 2, the maximum pass schedule when rolling is performed while accelerating and decelerating, and therefore the material to be rolled required before rolling is required. A common minimum temperature can be determined over the entire length.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a finish rolling mill including seven stands to which a pass schedule determination method according to a first embodiment of the present invention is applied.

FIG. 2 is a flowchart showing a procedure for calculating the maximum plate thickness for each stand by the pass schedule determination method of the present embodiment.

FIG. 3 is a diagram showing a rolling speed pattern applied to a pass schedule determination method according to a second embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a method of obtaining a maximum sheet bar thickness at a determination position on a material to be rolled, which is executed in a second embodiment.

FIG. 5 is a conceptual diagram showing a procedure for calculating a finishing inlet temperature from a pass schedule and a finishing outlet temperature.

[Explanation of symbols]

 F1 to F7 ... First to seventh stands of finishing rolling mill S ... Rolled material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshito Goto, 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Chiba Steel Works, Kawasaki Steel Co., Ltd. (72) Nobuaki Nomura, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Chiba Steel Works, Ltd.

Claims (5)

[Claims] 1. A method for determining a pass schedule of a continuous rolling mill when rolling a target material to be rolled on the delivery side of a final stand by a continuous rolling mill, wherein constraint conditions for equipment and operation are set for each stand, Using the target strip thickness, strip width, rolling temperature and rolling speed on the exit side of the final stand, the maximum strip thickness that can be rolled by each stand within the range of the above-mentioned constraint conditions is calculated retroactively from the final stand. A method for determining a pass schedule for a continuous rolling mill, characterized in that the pass schedule is determined using the maximum rollable plate thickness obtained for each stand as a guideline. 2. A method for determining a pass schedule of a continuous rolling mill when rolling a target material to be rolled on the exit side of a final stand according to a speed pattern accompanied by acceleration and deceleration by the continuous rolling mill, wherein By setting constraints on equipment and operation, and regarding the judgment position of the material to be rolled that corresponds to multiple judgment points on the speed pattern, the target plate thickness on the exit side of the stand,
Using the strip width, rolling temperature and rolling speed at each judgment point, the maximum sheet thickness that can be rolled at each stand within the range of the above-mentioned constraint conditions is calculated retroactively from the last stand, and each judgment of the material to be rolled is performed. Using the minimum value of the maximum plate thickness that can be rolled for each stand for the position as a guideline, determine a common pass schedule for the entire length of the material to be rolled. Method. 3. The path of a continuous rolling mill according to claim 1 or 2, wherein the constraint conditions set for each stand are rolling load, rolling torque, rotational driving force, rolling reduction and linear pressure. Schedule decision method. 4. The pass schedule determination method for a continuous rolling mill according to claim 1, further comprising calculating a minimum required rolling temperature at least on the first stand entrance side and using the rolling temperature as a guideline. 5. The method according to claim 2, further comprising calculating a necessary minimum rolling temperature on the entrance side of the first stand for each determination position of the material to be rolled, and cooling the rolled material until each determination position reaches the first stand. The air-cooling temperature is added to each of the above-mentioned rolling temperatures calculated for each judgment position to obtain the minimum temperature of the material to be rolled required at the same time point before rolling, and the maximum value among them is also used as a guideline. A method for determining a pass schedule of a continuous rolling mill, which is characterized by the above.