JPH10263630A - Rolling method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the quality of products by favorably preventing damage to the roll surface. A flow sensor 7a, a cooling fluid supply amount q _a relative rolling roll 1 at 7b, both to measure q _b, temperature measuring sensor 6 and thermocouple 9a, the entry side of the front and rear roll 1 cooling and at 9b egress The coolant temperatures T ₀ , T _a , and T _b are measured at the above conditions. The controller 10 calculates the supply amounts q _a and q _b and the temperature difference T ₀ − of the coolant between the inlet side and the outlet side before and after cooling the roll.
The amount of heat input to the roll 1 is calculated based on T _a , T ₀ −T _b, and the roll surface temperature of the roll bite is calculated based on the amount of heat input and the heat transfer analysis model formula of the roll 1. change transmission amount of rolling oil to to rolling oil injection nozzle 4 corrects the current command value I _C for the pump P ₁ in response to comparing the calculated value of the surface temperature and the preset value to the comparison result changing the rolling speed of the rolling machine by correcting a velocity command value V _C to be output to the mill from the process computer 11 as well as.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rolling method for performing rolling while supplying a cooling liquid and a rolling oil.

[0002]

2. Description of the Related Art As a conventional rolling method of this kind, for example, a method described in Japanese Patent Application Laid-Open No. 8-309410 is known. In this rolling method, first, the supply amount of the cooling liquid to the rolling roll is measured, and the temperature of the cooling liquid before and after cooling the rolling roll is measured. Next, the amount of heat input to the rolling roll is calculated based on the measured supply amount of the cooling liquid and the temperature difference of the cooling liquid before and after the cooling of the rolling roll, and based on the heat input and the heat transfer analysis model of the rolling roll. Calculate the roll surface temperature of the roll bite portion, and when the calculated value of the roll surface temperature becomes higher than the roll surface temperature set value set in advance below the critical temperature of heat streak occurrence, the supply amount of the rolling oil to the roll bite portion is increased. Conversely, when the roll surface temperature becomes lower than the set value, the supply amount of the rolling oil to the roll bite portion is reduced.

[0003] When the supply amount of the rolling oil to the roll bite portion is increased when the calculated value of the roll surface temperature is higher than the set value of the roll surface temperature, the heat generated by the friction between the rolled material and the roll in the roll bite portion is increased. Is reduced, and the plate temperature immediately below the roll bite portion is maintained lower than the critical temperature at which heat leak occurs, thereby reducing the rate of occurrence of the heat streak.

[0004]

However, when such a conventional rolling method is applied to hot rolling,
Despite increasing the supply amount of rolling oil in order to reduce the heat generated by the friction between the rolled material and the rolling roll in the roll bite, a part of the rolling oil burns due to high temperature and damages the roll surface (Komajo et al .: 29th Hot Rolled Sheet Technology Conference Material, 29 Hot Rolled-49 (1991))
It is difficult to keep the roll surface temperature just below the roll bite part low. As a result, there is an inconvenience that the roll surface is damaged, the product is damaged, and quality is deteriorated.

[0005] The present invention has been made in order to solve such inconveniences, and an object of the present invention is to provide a rolling method capable of favorably preventing damage to a roll surface.

[0006]

According to a first aspect of the present invention, there is provided a rolling method for performing rolling while supplying a cooling liquid and a rolling oil. Measuring the temperature of the cooling liquid before and after cooling the rolling roll, and measuring the amount of the cooling liquid and the temperature difference of the cooling liquid before and after cooling the rolling roll. The amount of heat input to the rolling oil is calculated, the calculated value of the amount of heat input is compared with a preset value, and the supply amount of the rolling oil and the rolling speed are adjusted according to the comparison result.

In a rolling method according to a second aspect of the present invention, in the rolling method of performing rolling while supplying a cooling liquid and a rolling oil, the supply amount of the cooling liquid to the rolling roll is measured, and the roll before and after the cooling of the rolling roll is measured. The temperature of the cooling liquid is measured, and the heat input to the rolling roll is calculated based on the measured supply amount of the cooling liquid and the temperature difference of the cooling liquid before and after cooling the rolling roll, and the heat input and the heat input The roll surface temperature of the roll bite portion is calculated based on the heat transfer analysis model of the rolling roll, and the calculated value of the roll surface temperature is compared with a preset set value. It is characterized in that the feed rate and rolling speed of the steel are adjusted.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory system diagram for explaining an example of an embodiment of the present invention, FIG. 2 is an explanatory system diagram for explaining another embodiment of the present invention, and FIG. 3 is displayed on a CRT. FIG. 4 is a graph showing the heat input amount of each stand, and FIG. 4 is a graph showing the roll surface temperature of each stand displayed on the CRT. In this embodiment, a case where the present invention is applied to a rolling roll of a final stand of a hot rolling tandem rolling mill is taken as an example.

As shown in FIG. 1, a cooling water jet nozzle 2 for jetting a cooling liquid toward the pair of rolling rolls 1, 1 is provided on the entrance side and the exit side of the pair of rolling rolls 1, 1. A rolling oil injection nozzle 4 for injecting rolling oil toward the pair of rolling rolls 1, 1 is provided on the entry side of the pair of rolling rolls 1, 1. The cooling water injection nozzles 2 are vertically arranged at four locations on both sides of the rolled material 3 on the entry side and the exit side of the rolling roll pairs 1 and 1, for a total of four locations. At the entry side of 1, the rolled material 3 is disposed at two locations in the vertical direction with the rolled material 3 interposed therebetween.

The cooling water injection nozzle 2 and a pump (not shown)
The cooling water supply pipe 5 interposed between the
Temperature sensor for measuring the temperature of the cooling water sent to the whirl 2
6 and cooling water injection nozzles on the inlet and outlet sides of the pair of rolling rolls 1, 1.
The amount of cooling water per unit time sent to the slur 2
And flow rate sensors 7a and 7b for measuring
You. One end of a rolling oil supply pipe 4a is connected to the rolling oil injection nozzle 4.
Is connected to the other end of the rolling oil supply pipe 4a.
P₁Is connected to the rolling oil tank 4b. Ma
A mixer 4c is provided in the middle of the rolling oil supply pipe 4a.
Are located. Mixer 4c has one end of hot water supply pipe 4d
Is connected, and the other end of the hot water supply pipe 4d is connected to a pump P
_TwoIs connected to the hot water tank 4e via the. And
Pump P ₁And P_TwoDrive the rolling oil tank 4b
The rolling oil is discharged to the mixer 4c and
Hot water is discharged from the water tank 4e toward the mixer 4c.
The rolling oil led out to the mixer 4c is
After being mixed and stirred with hot water, the rolling oil supply pipe 4a
Is sent to the rolling oil injection nozzle 4.

A cooling water receiving portion 8a for receiving the cooling water injected from the cooling water injection nozzle 2 on the input side of the rolling roll pair 1, 1 is provided below the rolling roll pair 1, 1; , 1 is provided with a cooling water receiving portion 8b for receiving the cooling water injected from the cooling water injection nozzle 2. Further, a thermocouple 9a for measuring the temperature of the cooling water after the roll is cooled at the inlet side is disposed in the inlet side cooling water receiver 8a, and the roll at the outlet side position is provided in the outlet side cooling water receiver 8b. A thermocouple 9b for measuring the temperature of the cooling water after cooling is provided.

Measurement signals measured by the thermocouples 9a and 9b, the temperature sensor 6 and the flow sensors 7a and 7b are output to the controller 10, and the controller 10
a, 9b and the detected temperature values T _a , T _b , T ₀ obtained by the temperature sensor 6 and the cooling water supply amounts q _a , q _b obtained by the flow rate sensors 7a, 7b. calculates the heat input Q _I to 1, further calculates the roll surface temperature T _MAx the roll bite portion based on the said input heat amount Q _I and heat transfer analytical model of the rolling roller 1 (described below.)
Then, by comparing the set value T _H which is previously set as the calculated value T _MAx of the roll surface temperature to correct the current command value I _C for the pump P ₁ in response to the comparison result to the rolling oil injection nozzle 4 speed command value V _C output from the process computer 11 to the rolling mill as well as changing the transmission amount of the rolling oil
Change the rolling speed of the rolling machine corrected and the further the calculated amount of heat input Q _I and a roll surface temperature T _MAx CRT 12
To graph.

More specifically, the controller 10 first
Temperature detection value of the cooling water of the front roll cooling obtained by the temperature measuring sensor 6 T _0, thermocouple temperature detection value of the cooling water after the roll cooling in the obtained entry side position by 9a T _a and the flow rate sensor 7a, Based on the cooling water supply amounts q _a , q _b to the rolling roll 1 obtained by 7b, the heat removal amount Q _a from the roll at the entrance position is calculated using the following equation (1), and the temperature is measured. The temperature detection value T ₀ of the cooling water before the roll cooling obtained by the sensor 6, the temperature detection value T _b of the cooling water after the roll cooling at the outlet side obtained by the thermocouple 9 _b, and the flow rate sensors 7 a and 7 b Based on the obtained cooling water supply amounts q _a and q _b to the rolling roll 1, a heat removal amount Q _b from the roll at the outlet position is calculated using the following equation (2).

Q _a = q _a · (T ₀ -T _a ) · C · ρ (1) Q _b = q _b · (T ₀ -T _b ) · C · ρ (2) C: cooling water specific heat, [rho: the density of the cooling water here, since during the rolling heat input and heat removal of the rolling roller 1 is in equilibrium, the heat removal amount Q _b in heat removal amount Q _a and the exit-side position at the entry side position the combined bets regarded as heat input Q _I into the rolling roll 1.

Next, based on the heat input Q _I , the roll surface temperature T of the roll bite is calculated using an unsteady one-dimensional heat conduction model shown in the following equation (3). θ ₁ ′ = 2T · [θ ₀ + ｛(１ ／ T) −1｝ θ ₁ + Q _I · (δ / λ)] (3) T = (λ / Cρ) · (Δt / δ) Q _I: heat flux (heat input) [kcal / m ² h ℃] lambda: thermal conductivity [kcal / mh ° C.] C: specific heat [kcal / kg ° C.] [rho: density [kg / m ^2] [delta]: dividing element [M] Δt: time step [h] θ ₁ , θ ₀ : temperature at a position relatively separated by δ [° C.]
(It is assumed that heat conduction occurs from the position corresponding to θ ₁ to the position corresponding to θ _0. ) By sequentially determining θ ₀ and θ ₁ in Expression (3) along the direction of heat conduction, The roll surface temperature T can be determined. The roll surface temperature T becomes the maximum temperature T _MAX at the roll bite part exit position, and the roll surface temperature T _MAX at the roll bite part exit position and the above-mentioned heat input Q _I are CR, respectively.
A graph is displayed at T12.

Next, a comparison is made between the roll surface temperature T _MAX at the position where the roll bite exits and the set value T _H which is previously set to a temperature lower than the roll surface critical temperature T _{P at} which the rolling roll is damaged. rolling supplied transmission quantity of rolling oil to the current command value I _C for correcting the rolling oil injection nozzle 4 with respect to the pump P _1, the rolling oil injection nozzle 4 in other words to the rolling roll 1 according to the comparison result Te the speed command value V _C output from the process computer 11 to the rolling mill with changing the supply amount of the oil by correcting change the the rolling speed.

[0017] That is, when the roll surface temperature T _MAX in the roll bite portion outlet side position is lower than the set value T _H, the current command value I _C is rolling oil injection nozzle 4 without correcting to the pump P ₁
Rolling oil supplied to the reduction rolls 1 from as well as the normal supply, also the normal operation as it does not correct the speed command value V _C output from the process computer 11 to the rolling mill.

When the roll surface temperature T _MAX becomes higher than the set value T _H , an alarm is output and at the same time, the pump P ₁
Together by correcting the current command value I _C to increase the supply amount of rolling oil to be supplied to the rolling roll 1 from rolling oil injection nozzle 4 to, the process by outputting a speed correction signal to the process computer 11 correcting the velocity command value V _C output from the computer 11 to the rolling mill by reducing the rolling speed. This will heat input Q _I of the rolled material 3 and is heat generation reduces due to friction with the rolling roller 1 to the rolling roll 1 is reduced in the roll bite portion, a part of the rolling oil is hot, as in this embodiment Therefore, even in the case of hot rolling that burns, the roll surface temperature immediately below the roll bite portion can be kept low. As a result, the heat load on the rolling roll 1 is reduced, and damage to the roll surface can be satisfactorily prevented.

In the above embodiment, the heat input Q_ITo
Based on heat transfer analysis model formula
Roll surface temperature T at the exit side position_MAXAnd set value T_HAnd
Compare the supply amount of rolling oil and the rolling speed according to the comparison result.
The case of adjusting the temperature is taken as an example.
Quantity Q_IAnd the allowable heat input Q at which the rolls will be damaged in advance
_PSet value Q set to a lower temperature than_HAnd comparing
Adjust the supply amount of rolling oil and rolling speed according to the comparison result.
And the roll surface temperature T _MAXas well as
Heat input Q_IAnd the set value T_HOr set value Q_H
And the supply amount and pressure of the rolling oil according to the comparison result.
The rolling speed may be adjusted.

In the above embodiment, the flow sensors 7a and 7b for the entrance and exit of the pair of rolls 1, 1 are provided, and the inlet and exit sides of the pair of rolls 1, 1 are individually cooled. Although the water supply amounts q _a and q _b are measured, if the flow ratio of the cooling water on the inlet side and the outlet side is known in advance, the cooling water supply pipe 5 in FIG. And one flow sensor is installed upstream of the branch point for the outlet side, and the total amount of the inlet side cooling water supply amount and the outlet side cooling water supply amount is measured, and the total amount and the flow amount are measured. it may be obtained cooling water supply amount q _b of the outlet side and the cooling water supply amount q _a of the entering-side from the ratio.

Further, in the above embodiment, the case where the present invention is applied to a hot rolling mill is taken as an example. However, the present invention is not limited to this, and the present invention is applied to a cold rolling mill and a wet-type temper rolling mill. Of course, the invention can be applied.

Further, in the above embodiment, the case where the present invention is applied to the rolling rolls of the final stand of the hot rolling tandem rolling mill is taken as an example. The present invention may be applied, and as shown in FIG. 2, the present invention may be applied to all the stands. In this case, the CRT 12, as shown in FIGS. 3 and 4, the amount of heat input Q _I and a roll surface temperature T _MAX for each stand F1~F7 is displayed.

[0023]

As is clear from the above description, according to the present invention, the heat generation due to the friction between the rolled material and the roll in the roll bite portion is reduced, and the heat input to the roll is reduced. The roll surface temperature immediately below the roll bite portion can be kept low, and as a result, the heat load on the rolling roll can be reduced and the roll surface can be prevented from being damaged, and the quality of the product can be improved. The effect that it can be achieved is obtained.

In addition, since the wear of the roll is reduced by reducing the rolling speed and increasing the supply amount of the rolling oil, ton / s
et can be enlarged, and a rolling method suitable for endless rolling, in particular, in which the roll temperature tends to increase, can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory system diagram for explaining an example of an embodiment of the present invention.

FIG. 2 is an explanatory system diagram for explaining another embodiment of the present invention.

FIG. 3 is a graph showing a heat input amount of a work roll of each stand displayed on a CRT.

FIG. 4 is a graph showing the surface temperature of a work roll of each stand displayed on a CRT.

[Explanation of symbols]

1 ... rolling rolls 2 ... cooling water jetting nozzle 3 ... rolled material 4 ... rolling oil jet nozzle 4a ... rolling oil supply pipe 4b ... rolling oil tank 4c ... mixer 4d ... hot water supply pipe 4e ... hot water tank P ₁ ... pump 6 ... measurement Temperature sensor 7a Inlet cooling water flow sensor 7b Outlet cooling water flow sensor 8a Inlet cooling water receiver 8b ... Outlet cooling water receiver 9a, 9b Thermocouple 10 Controller 11 Process computer 12 CRT

Claims (2)

[Claims] In a rolling method of performing rolling while supplying a cooling liquid and a rolling oil, a supply amount of the cooling liquid to a rolling roll is measured, and a temperature of the cooling liquid before and after cooling the rolling roll is measured. Calculating the amount of heat input to the rolling roll based on the measured supply amount of the cooling liquid and the temperature difference of the cooling liquid before and after the cooling of the rolling roll, and calculates a calculated value of the heat input and a preset value And adjusting the supply amount and the rolling speed of the rolling oil according to the comparison result. 2. In a rolling method of performing rolling while supplying a cooling liquid and a rolling oil, a supply amount of the cooling liquid to the rolling roll is measured, and a temperature of the cooling liquid before and after cooling the rolling roll is measured. Calculating the amount of heat input to the rolling roll based on the measured supply amount of the cooling liquid and the temperature difference of the cooling liquid before and after cooling the rolling roll, and analyzing the heat input and the heat transfer of the rolling roll. Calculate the roll surface temperature of the roll bite portion based on the model, compare the calculated value of the roll surface temperature with a preset set value, and supply the rolling oil and the rolling speed according to the comparison result. A rolling method characterized by adjusting the following.