JP3235449B2 - High speed cold rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for realizing high-speed rolling by preventing chattering occurring during high-speed cold rolling in sheet rolling.

[0002]

2. Description of the Related Art Chattering and heat scratches are phenomena that hinder stable rolling during high-speed rolling in sheet rolling. The occurrence of these phenomena hinders high-speed rolling and causes a reduction in productivity. The well-known chattering is a vibration phenomenon in which excessive lubrication occurs in the roll tool during acceleration / deceleration in the middle / low speed range of the rolling, and as a result, the neutral point jumps out of the roll tool and is triggered by this. .
Chattering in this case is accompanied by phenomena such as a decrease in the coefficient of friction and a decrease in the advance ratio. It is known that many factors such as lubricating oil, vibration characteristics of a rolling mill, rolling reduction, material of a rolled material, roll surface temperature, plate surface temperature, rolling speed, and rolling schedule are affected.

On the other hand, as a conventional technique for preventing chattering, there is a technique which pays attention to an advance rate as a control factor. This is to set the target advance rate from the friction coefficient prediction formula to realize stable rolling without chattering,
Method for determining the concentration of lubricating oil (JP-A-3-151106)
), A method of setting a rolling schedule (Japanese Unexamined Patent Application Publication No.
There is a method of determining the lubricating oil supply amount (Japanese Patent Publication No. 6-13126). Further, in order to prevent roll slip, a method of controlling the plate tension and the gap using the rate of change of the measured advance rate as an index (Japanese Unexamined Patent Application Publication No.
9113). Also, a method of preventing chattering by controlling the surface temperature of a work roll to an optimum temperature range as a control factor (JP-A-57-156)
807). Each of these methods is a method for preventing chattering caused by excessive lubrication, that is, a decrease in friction coefficient and a decrease in advanced rate. As a control method, a method of lowering the concentration of the lubricating oil, setting a rolling schedule, reducing the amount of lubricating oil supply oil, etc. in order to increase the friction coefficient and the advanced ratio is fundamental.

[0004]

However, high-speed and high-speed rolling has been carried out due to the recent trend in tin material hardening and thinning of gauges, and accordingly, high-speed rolling has been promoted to improve productivity. ing. In the production process of the above product, there is a problem that chattering occurs in a high-speed rolling zone, which has not occurred conventionally, and hinders high-speed rolling operation. This is recognized in the prior art, as described below.
Chattering that occurs under conditions that are not
This is due to insufficient lubrication in the high speed rolling region. The present invention
Causes chattering due to such insufficient lubrication
And provide a means for stably achieving high-speed rolling.
To offer.

[0005]

According to a first aspect of the present invention, there is provided a high-speed cold rolling method according to the first aspect of the present invention, wherein a steel sheet temperature during rolling, a work roll temperature, a rolled sheet speed and a cold rolling method using a tandem rolling mill. The work roll rolling speed was measured, an estimated value of the amount of lubricating oil introduced was calculated based on these measured values, and the calculated estimated value of the amount of lubricating oil introduced was compared with the previously determined high-speed rolling zone (oil pit). Area ratio is 50%
Hereinafter, it refers to a region where the rolling speed is 1000 mpm or more.
same as below. ) Is compared with the lower limit of the amount of lubricating oil introduced when chattering occurs. If the estimated value is less than or equal to this lower limit, the estimated value of the amount of lubricating oil introduced is greater than or equal to the lower limit. The amount of oil supplied to the lubricating oil system is controlled in such a manner as to be as follows.

According to a second aspect of the present invention, there is provided a high-speed cold rolling method, comprising:
The steel sheet temperature during rolling, the work roll temperature, the rolling plate speed and the work roll rolling speed were measured, and an estimated value of the lubricating oil introduction oil amount was calculated based on these measured values. The estimated value is compared with the lower limit of the amount of the lubricating oil introduced when chattering occurs in the high-speed rolling zone, which has been obtained in advance, and when the above estimated value is equal to or less than the lower limit, the normal concentration or the normal viscosity is determined. Is switched from a lubricating oil system that supplies lubricating oil to a lubricating oil system that supplies lubricating oil of high concentration or high viscosity, or the two lubricating oil systems are used in parallel.

[0007] The high-speed cold rolling method according to claim 3 of the present invention is a cold rolling method using a tandem rolling mill for a steel sheet,
The steel sheet temperature during rolling, the work roll temperature, the rolling plate speed and the work roll rolling speed were measured, and an estimated value of the lubricating oil introduction oil amount was calculated based on these measured values. The estimated value is compared with the lower limit of the amount of lubricating oil introduced when chattering occurs in the high-speed rolling zone, which has been determined in advance, and when the estimated value is less than or equal to the lower limit, the stand entry side upstream section High-concentration oil is applied to the upper and lower work rolls of the steel plate or the upper and lower work rolls on the stand entry side.

[0008] The high-speed cold rolling method according to claim 4 of the present invention is characterized in that, in the cold rolling method using a tandem rolling mill for a steel sheet,
The steel sheet temperature during rolling, the work roll temperature, the rolling plate speed and the work roll rolling speed were measured, and an estimated value of the lubricating oil introduction oil amount was calculated based on these measured values. Compare the estimated value with the lower limit of the amount of lubricating oil introduced when chattering occurs in the high-speed rolling zone determined in advance, and when the above estimated value is equal to or less than this lower limit, the work roll and the steel sheet are removed. It controls the flow rate of the coolant to be cooled.

[0009] A high-speed cold rolling method according to claim 5 of the present invention is characterized in that, in the cold rolling method using a tandem rolling mill for a steel sheet,
The high-speed cold rolling method according to any one of claims 1 to 4 is performed on one or both of the final stand and the immediately preceding stand.

[0010] By applying the high-speed cold rolling method according to the above-mentioned claims to a tandem rolling mill for steel sheets, it is possible to prevent chattering caused by insufficient lubrication in the conventional high-speed rolling region.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors have conducted various studies so far to elucidate the mechanism of chattering in the high-speed rolling region of a hard / thin gauge tin material. FIG.
Fig. 1 is a diagram showing the measurement results of the oil pit ratio of the steel sheet surface at the time of chattering and at the time of stable rolling where chattering does not occur . When a tin plate of .21 mm or less was rolled, the chattering occurred in the low-speed rolling zone, the chattering occurred in the high-speed rolling zone, and the oil pit area ratio of the sample surface of each rolled steel sheet during stable rolling was measured. The result. The case where chattering occurs is indicated by a cross.
Have . The figure shows that the oil pit area ratio is large.
And that chattering is occurring when it is small
I understand. If the oil pit area ratio is large,
Chatter occurs without much dependence on the rolling speed
If the oil pit area ratio is small, the rolling speed
You can see that it occurred in the area exceeding 1000 mpm
You. Here, when the oil pit area ratio is small,
Indicates an oil pit area ratio of 50% or less. You
That is, the present inventors have found that chattering occurs at the rolling speed.
Chatter caused by excessive lubrication that is not very dependent on
Occurs at a certain rolling speed or more, and is caused by insufficient lubrication
It is clear that there is chattering. So
In the prior art, the rolling roll and steel
Slip between the plate and chatterin
Has been recognized that
This is to prevent chattering caused by many
In FIG. 11, the pit area ratio exceeds 50%.
The target is chattering that occurs in. On the contrary,
According to the present invention, in FIG.
%, In the high-speed rolling region where the rolling speed is 1000 mpm or more
Chattering that occurs, i.e.,
This is to prevent occurrence of chatter.

FIG. 12 is a diagram showing the relationship between the rolling speed and the amount of oil adhering to a steel sheet after rolling. The figure is based on the result of actually examining the rolling speed and the amount of oil adhering to a steel sheet after rolling. . FIG. 12 shows that there is a tendency for insufficient lubrication to occur in the high-speed rolling region. From the above study, it was found that chattering generated during high-speed rolling was caused by insufficient lubrication between the strip and the roll in the high-speed range. Therefore, this will be referred to as chattering due to insufficient lubrication to distinguish it from conventional chattering.

There are various possible causes of insufficient lubrication in the high-speed rolling zone. First, the following (1) and (2) are mentioned. (1) Since the strip temperature increases and the lubricating oil temperature near the roll bite is high, the viscosity of the rolling oil decreases, and the amount of lubricating oil drawn into the roll bite decreases. (2) In high-speed rolling, the spraying time of the lubricating oil on the surface of the steel sheet decreases, and the amount of lubricating oil supply oil decreases. In addition,
It is considered that chattering is likely to occur in a thin material, and the surface pressure at the roll bite inlet increases, so that the amount of oil introduced into the roll bite may decrease.

Mainly due to the above reasons, the amount of oil introduced into the roll bite decreases, resulting in insufficient lubrication. As a result, the oil film thickness in the roll bite decreases, so that the oil film becomes uneven and the frictional state becomes unstable. At that time, it is considered that chattering is generated by operating conditions such as a change in tension as a trigger. On the other hand, the conventional chattering prevention technology is for chattering caused by excessive lubrication in the contact arc between the strip and the roll, and it has been found that the mechanism of occurrence is different from chattering occurring in a high-speed region. . Therefore, if the conventional technology, which is a measure to prevent chattering due to excessive lubrication, is applied to the high-speed rolling zone, chattering due to insufficient lubrication will have an adverse effect, and it will be clarified that chattering due to insufficient lubrication cannot be prevented. did.

As a result of intensive studies, the inventors have found that, as shown in FIGS. 11 and 12, there is a strong correlation between chattering and the amount of oil introduced into the roll bite. Embodiments 1 to 5 of the present invention calculate the introduced oil amount estimated value by measuring the steel sheet temperature during rolling, the work roll temperature, the rolled sheet speed and the work roll rolling speed based on such knowledge, and in the high speed rolling zone. If the value is lower than the lower limit of the amount of introduced oil when chattering occurs,
This is a method for preventing chattering occurring in the high-speed rolling zone by controlling various devices for supplying the lubricating oil so as to exceed the lower limit of the amount of the introduced oil. First, the outline of Embodiments 1 to 5 will be described. Embodiment 1 is a cold rolling method for controlling the amount of lubricating oil supply oil during high-speed rolling, and Embodiment 2 is a high-concentration rolling oil during high-speed rolling. The third embodiment is a cold rolling method using a lubricating oil system that supplies high-viscosity oil during high-speed rolling. Further, Embodiment 4 is a method in which high-concentration oil is applied to the upper and lower surfaces of a steel plate at the upstream portion on the stand entry side during high-speed rolling to perform cold rolling. This is a method of performing cold rolling by applying high-concentration oil to upper and lower work rolls.

Further, as a result of intensive studies, the inventors have found that there is a strong correlation between the steel plate and roll cooling conditions and the occurrence of chattering. FIG.
It is a figure which shows the relationship between the roll cooling flow rate and the rolling speed at the time of chattering generation | occurrence | production, In the same figure, it is the result of having investigated the relationship between the steel plate and roll cooling conditions, and the rolling speed until chattering generation | occurrence | production in a tandem rolling mill. FIG. 13 shows that chattering can be prevented by controlling the flow rate of the spray for cooling the steel plate and the roll.
The sixth embodiment measures the steel sheet temperature during rolling, the work roll temperature and the rolled sheet speed to calculate an estimated oil introduction amount based on such knowledge, and calculates the lower limit of the introduced oil amount when chattering occurs in the high-speed rolling region. This is a cold rolling method for controlling the flow rate of the coolant for cooling the roll and the steel sheet when the value falls below this value.

In a tandem rolling mill, when chattering occurs at a certain stand, the mill vibration propagates to the front and rear stands via the steel plate between the stands. The inventors have considered that it is effective to implement a chattering prevention measure for a trigger stand where chattering occurs first. Therefore, for the purpose of investigating stands where chattering occurs in the high-speed rolling zone in actual operation, vibration accelerometers are installed in the housings of the # 3 to # 5 stands after the tandem mill of all five stands, and the stands where chattering occurs are installed. investigated. FIG. 14 shows a five-stage stand
It is a figure which shows the example of a measurement of the vibration acceleration in the housing of a stand # 3-# 5 stand of the latter stage of a tandem mill, and is based on the above-mentioned investigation result. In the measurement example of FIG. 14, it can be seen that the vibration of the housing of the # 5 stand occurs first, and then the vibration propagates to the previous stands, # 4 and # 3 stands. As a result of repeating the same data collection, it was found that the frequency of occurrence at the last stand of the tandem rolling mill and the stand immediately before it was high. Embodiment 7 is based on such knowledge, in one or both of the last stand of the tandem rolling mill and the immediately preceding stand,
This is a cold rolling method for performing any one of the first to sixth embodiments.

Further, in the first to fifth embodiments, the estimated value of the amount of oil introduced into the roll bite which has a strong correlation with the occurrence of chattering is used as a control index. Then, the lower limit value at the occurrence of chattering is determined in advance, and the lubricating oil supply device is controlled so as to exceed the lower limit value, and the amount of oil introduced into the roll bite is set to exceed the reference value to prevent chattering. ing. Specifically, the amount, concentration, and viscosity of the supplied oil of a normal lubricating oil supply device are controlled. further,
In addition to the usual lubricating oil supply device, the amount of oil introduced into the roll bite is controlled by using a device for pre-coating the steel plate and the roll surface with a high-concentration rolling oil. In emulsion oil lubrication, which is commonly used in tandem rolling of tin plate, etc., one of the factors governing the amount of oil introduced into the roll bite is the adhesion of oil in the emulsion to the steel plate surface and the roll surface (plate Out)) amount. The plate-out amount of the rolling oil is generally affected by the amount of the supplied oil, the concentration, the spraying time, and the surface temperature of the material to be sprayed.

In the first embodiment, depending on the amount of lubricating oil supplied,
In Embodiment 2, depending on the concentration of the lubricating oil, in Embodiments 4 and 5, a pre-coating device is used to control the spray time of the lubricating oil on the rolls and the steel sheet surface,
The amount of plate-out on the surface of the steel sheet and the surface of the roll is controlled to achieve a desired amount of introduced oil. Another factor governing the amount of oil introduced into the roll bite is the viscosity of the rolling oil. It is generally known that the higher the viscosity of the oil, the larger the amount of the introduced oil, and the third embodiment utilizes this principle.

In the sixth embodiment, the respective surface temperatures are controlled by the cooling conditions of the steel plate and the roll. The first effect of controlling the steel sheet temperature and the roll surface temperature is that the amount of plate-out to the steel sheet surface and the roll surface can be controlled. FIG. 15 is a diagram showing the relationship between the plate-out amount and the steel plate temperature. FIG. 15 shows the result of investigating the relationship between the steel plate temperature and the plate-out amount using a plate-out tester. According to FIG. 15, it is inferred that there is a correlation between the two and the plate-out amount can be controlled by controlling the temperature. The second effect is a low-frequency effect of the boundary lubrication friction coefficient by controlling the interface temperature in the roll bite.

FIG. 19 is a graph showing the relationship between the coefficient of friction and the steel sheet temperature. FIG. 19 shows a test piece in which a certain amount of a tallow-based cold-rolling oil is uniformly applied on the surface in advance to obtain various steel sheet temperatures. 3 shows the relationship between the steel sheet temperature and the friction coefficient when the Bowden test was performed under the following conditions. The coefficient of friction is
This is the average friction coefficient of the stationary part before the occurrence of image sticking. The Bowden test conditions in FIG. 19 are as follows. Test material: Tin raw material Steel ball: SUJ-2 Load: 3.0 kg Sliding speed: 4.0 mm / sec Sliding distance: 30 mm Rolling oil: tallow rolling oil As shown in FIG. 19, the temperature range of the steel sheet where the boundary friction coefficient decreases. You can see that there is. From this result, it is inferred that the boundary friction coefficient can be controlled by controlling the interface temperature between the roll bite and the steel sheet. It is considered that lowering the boundary friction coefficient has an effect of indirectly supplementing insufficient lubrication. The sixth embodiment is a technique for preventing chattering by using the above two effects. Further, in the seventh embodiment, a stand that is frequently used as a chattering trigger stand or a stand immediately before the stand is used.
By performing the processing of each of the above-described embodiments, occurrence of chattering is prevented beforehand.
Embodiments 1 to 6 described below are examples in which each processing is applied to the final stand of a tandem rolling mill of all five-stage stands so that the effects of Embodiment 7 can be obtained.

Embodiment 1 FIG. 2 is a configuration diagram of a rolling mill according to Embodiment 1 of the present invention.
Is a plate thermometer, 2B is a roll thermometer, 3 is a plate speed meter, 4 is a tachometer, 5 is a flow meter, 6 is a pressure control valve, 7 is a calculator,
8 is a coolant control valve control device, 9 is a pump, and 10 is a lubricating oil tank. Embodiment 1 of FIG. 2 implements a cold rolling method for controlling the amount of oil supplied to a lubricating oil system during high-speed rolling. In order to obtain the effect of Embodiment 7, the calculation device 7 of FIG. The flow rate control valve of the last stand is controlled by a command. FIG. 1 is a flowchart showing a processing sequence of the high-speed cold rolling method according to the first embodiment of the present invention. Numerical values following S in FIG. 1 indicate step numbers.

The first embodiment will be described in the order of steps shown in FIG. In S1, the steel sheet temperature and the work roll temperature during rolling are measured by the thermometers 2A and 2B. Thermometer 2A, 2
As B, a non-contact radiation thermometer can be used, but a contact thermometer such as a thin film thermistor thermometer may be used. The entrance side plate speed is measured by a plate speed meter 3 such as a laser type non-contact speed meter or a roller type contact speed meter. Further, the work roll rolling speed is measured by the tachometer 4. Alternatively, the steel sheet and roll temperatures may be estimated from a heat balance calculation model.

In S2, the rolling schedule, the roll diameter, the measured values of S1 and the physical properties of the lubricating oil (viscosity pressure coefficient, viscosity temperature coefficient, reference viscosity, emulsion particle size,
Based on the concentration, the estimated value of the amount of lubricating oil introduced into the entry side tool is calculated by the following method. Generally, the estimated value of the introduced oil amount is derived by a mathematical method using the Reynolds equation, the energy equation, and the rolling oil viscosity equation according to the fluid lubrication theory. The equation for estimating the amount of introduced lubricating oil t _d is generally
The following equation (1) is obtained. _{t d = f (T S,} T R, C, d, ω, τ, α, β, η 0, T 0, φ 1, p 1, U R, U S) ... (1) where, T _R: Roll temperature, T _s : steel sheet temperature, C: rolling oil concentration (%), d: emulsion particle size (μm), ω: flow density of rolling oil, τ: spray time, α: viscosity pressure coefficient of rolling oil, β : Viscosity temperature coefficient, η ₀ : reference viscosity, T ₀ :
Oil temperature at reference viscosity, φ ₁ : bite angle (= (Δh / R)
^1/2 , Δh: reduction amount, R: roll diameter), p ₁ : deformation resistance of entry material, U _R : roll speed, U _S : entry plate speed

For example, Shodoshima et al. (Plasticity and Processing vol.19,
No. 214, pp. 958-965 (1978-11)), there is an example in which the amount of introduced oil is estimated in consideration of a temperature rise caused by shearing of a lubricating oil at an oil film. In this method, it is necessary to perform repeated calculations by a numerical computer. In addition, the mean value _{T m = (T R + T} S) of the rolling oil film temperature T _m of the roll temperature and temperature of the steel strip and a small effect of temperature rise due to shearing of the lubricating oil / 2 Assuming, rolling oil viscosity equation From the equation and the Reynolds equation, an equation for obtaining the amount of introduced oil is analytically obtained and is as shown in equation (2).

[0026]

(Equation 1)

H ₂ is generally considered to be the sum of the plate-out amounts of the surface of the steel sheet and the surface of the roll, and is expressed as in equation (3). h ₂ = ξ · (q _S + q _R ) (3) where, q _S : plate-out amount on the steel plate surface, q _R : plate-out amount on the roll surface, ξ: tuning coefficient (where 0 ≦ ξ ≦ 1) In general, the amount of plate-out on the steel sheet surface and the roll surface is a function of the concentration of the rolling oil, the emulsion particle size, the coolant flow rate density, the spray time, and the surface temperature of the adhered surface. )
Given by q _S = q ₁ (T _S , C, d, ω, τ) (4A) q _R = q ₂ (T _R , C, d, ω, τ) (4B) where q _S : steel sheet surface plate-out amount of, q _R: plate out amount of the roll surface, T _S: steel sheet surface temperature, T
_R : Roll surface temperature, C: Lubricating oil concentration, d: Emulsion particle size, ω: Lubricating oil flow density, τ: Spray time

The present inventors conducted a test using a plate-out tester to investigate the relationship between the plate-out amount and the steel plate temperature, concentration, particle size, and spraying time. As shown in FIG. Then, based on the results of FIGS. 15 to 18, an empirical equation as shown in the following equation (5) is obtained. q = f ₁ (C%) · f ₂ (d) · K ₁ (T) · [1-EXP (−K ₂ (T) · ω · τ)] (5) where q: to the adhesion surface , Ω: Coolant flow density, τ: Spray time, K ₁ (T), K ₂ (T): Coefficients depending on the surface temperature of the adhered surface and are derived experimentally. f ₁ (C%): a coefficient for correcting the effect of the rolling oil concentration, f ₁
= A ₁ + b ₁ · C (%). Here, a ₁ and b ₁ are constants and are derived experimentally. f ₂ (d): a coefficient for correcting the effect of the emulsion particle size,
₂ = a ₂ + b ₂ · d. Here, a ₂ and b ₂ are constants and are derived experimentally. In S2, the above equation (1) (for example, equations (2) to (2))
From (5)), an estimated value of the amount of lubricating oil introduced into the entry side bite is calculated.

In S3, the lower limit (t _d ) _lim of the introduced oil amount at which chattering occurs is compared with the introduced lubricating oil amount t _d calculated in S2 to determine whether or not t _d is smaller than (t _d ) _lim. Determine. Here, the lower limit value of the introduced oil amount at which chattering occurs
(t _d ) _lim is the value when chattering occurs in advance.
Work roll temperature, steel plate temperature, inlet side plate speed, roll speed, bite angle, lubricating oil initial concentration, emulsion particle size,
Data on lubricating oil properties, deformation resistance of the rolled material on the roll tool entry side, rolling oil flow rate, and the like are collected, and the limit introduction oil amount (t _d ) _lim at which chattering occurs is calculated from equation (1). deep. The difference between t _d and (t _d ) _lim calculated in S2 is as shown in equation (6). Δt _d = (t _d ) _lim −t _d (6) If the estimated value of the amount of oil introduced at the entry byte falls below the lower limit, that is, if Δt _d > 0, chattering due to insufficient lubrication may occur. It is determined that the possibility is high. If Δt _d > 0, control of the amount of introduced oil is performed in the next S4, and if not, the flow returns to S1.

In S4, if Δt _d > 0 is determined in S3, control is performed so that the amount of introduced oil exceeds the lower limit. Note that only the control method in S4 differs depending on the first to sixth embodiments. In the first embodiment, the amount of lubricating oil supplied is controlled.
In the above equation (1), the amount of change in the amount of introduced oil due to the lubricating oil supply control is expressed as in equation (7).

[0031]

(Equation 2)

In order to obtain the above-mentioned ΔT _S / Δω, a relational expression between the lubricating oil supply amount and the steel plate temperature is introduced. Although several relational expressions have been proposed, here, for example, Expression (8) based on a heat transfer equation is used.

[0033]

(Equation 3)

Here, T _S : steel sheet temperature after lubricating oil is supplied, T _Sb : steel sheet temperature before lubricating oil is supplied, T _C : coolant temperature, h: heat transfer coefficient of coolant, ρ _S :
Steel plate density, c _s : steel plate specific heat, h _s : steel plate thickness, t: lubricating oil cooling time (= (coolant cooling area length) / U _S )
According to experiments, a relational expression between the heat transfer coefficient and the spray flow density is as shown in Expression (9). h = K · A · ω (9) where K: constant, A: lubricating oil supply area, ω: lubricating oil flow density From equations (8) and (9), ΔT _S / Δω
Is derived as shown in Expression (10).

[0035]

(Equation 4)

The flow density Δω of the lubricating oil that satisfies the difference in the amount of introduced oil determined by the equation (6) is calculated by the equations (7) and (10).
Is obtained from equation (11) using

[0037]

(Equation 5)

The relationship between the spray flow rate Q and the flow density is as follows:
From ω · A (A: lubricating oil supply area), the lubricating oil supply change amount ΔQ is given by equation (12). ΔQ = Δω · A (12) The calculation device 7 of FIG. 2 outputs the supply change amount ΔQ as a control command value, and based on the command value, the coolant control valve control device 8 causes the pressure of the last stand of the lubricating oil supply system to be changed. The control valve 6 is controlled.

Embodiment 2 FIG. 4 is a configuration diagram of a rolling mill according to Embodiment 2 of the present invention, and 1 to 9 in FIG. 4 are the same as those in FIG. 10A is the first lubricating oil supply system tank, 1
0B is a second lubricating oil supply system tank for high concentration lubricating oil, 1
1 is a concentration meter, 12 is a concentration adjuster, 13 is a mixing tank, 14 is a crude oil tank, and 15 is a hot water tank. FIG.
Embodiment 2 has two lubricating oil supply systems and two lubricating oil recovery systems. The first lubricating oil supply system constitutes a circulation system that supplies lubricating oil of a normal concentration to the # 1 to # 5 stands, collects waste oil, and returns it to the first lubricating oil supply tank. The second lubricating oil system is a system that supplies high-concentration oil only to the final stand, adjusts the concentration after collection, and then returns the oil to the second lubricating oil tank. The two lubricating oil supply systems are switched and used or two supply systems are used in parallel based on a command from the calculation device 7 in the figure. In the example of FIG. 4, the seventh embodiment is applied, and this lubricating oil switching or parallel processing is performed on the final stand.

FIG. 3 is a flowchart showing the processing sequence of the high-speed cold rolling method according to Embodiments 2 and 3 of the present invention.
The processes of step numbers S1 to S3 in the figure are the same as those in FIG. In S4 of FIG. 3, in the second embodiment, the first lubricating oil is a normal concentration lubricating oil, and the second lubricating oil is a high concentration lubricating oil. In the third embodiment, the first lubricating oil is a first lubricating oil. The oil is a normal-viscosity lubricating oil, and the processing content of this step is read assuming that the second lubricating oil is a high-viscosity lubricating oil. In the second embodiment, in S4 of FIG.
If it is determined that Δt _d > 0 in 3, the first lubricating oil system, which is a normal concentration lubricating oil, is switched from the second lubricating oil system, which is a high concentration lubricating oil, or the first and second lubricating oil systems are switched. Use with a lubricating oil system. When chattering is unlikely to occur when Δt _d <0, the first lubricating oil system is usually used.

Embodiment 3 FIG. FIG. 5 is a configuration diagram of a rolling mill according to Embodiment 3 of the present invention, in which 1 to 9, 10A, and 10B are the same as those in FIG. Reference numeral 16 denotes a waste liquid tank. In the third embodiment of FIG. 5, similarly to FIG. 4, two lubricating oil supply systems are provided, and the second lubricating oil supply system supplies high-viscosity oil. The first lubricating oil supply system supplies the normal viscosity oil over the # 1 to # 5 stands, and
A circulation system is configured to collect waste oil from four stands and return it to the first lubricating oil supply tank. The second lubricating oil system supplies high viscosity oil only to the # 5 stand. The waste oil from the # 5 stand is collected in a waste oil tank. The two lubricating oil supply systems are switched and used or two supply systems are used in parallel based on a command from the calculation device 7 in the figure. The processing sequence of the third embodiment is the same as that of the flowchart of FIG. 3, and the first lubricating oil and the second circulating oil in S4 may be read as normal viscosity oil and high viscosity oil, respectively.

Embodiment 4 FIG. FIG. 7 is a configuration diagram of a rolling mill according to Embodiment 4 of the present invention.
Is the same as FIG. Reference numeral 17 denotes a precoat tank for storing high-concentration oil. Reference numeral 18 denotes a precoat application device. FIG. 7 shows only the last stand of a tandem rolling mill of five-stage sundand. In Embodiment 4 of FIG. 7, the pressure control valve for precoat is controlled based on a command of the calculation device 7 in the drawing during high-speed rolling, and the precoat coating device 18 provided on the upstream side of the stand entry side supplies high-concentration oil. This is a processing method for applying cold rolling to the upper and lower surfaces of a steel sheet.

FIG. 6 is a flowchart showing the processing sequence of the high-speed cold rolling method according to Embodiments 4 and 5 of the present invention.
The processes of step numbers S1 to S3 in the figure are the same as those in FIG. In S4 of FIG. 6, the location where the high-concentration oil is applied is the upper and lower surfaces of the steel plate on the upstream side of the stand entrance in the fourth embodiment, and the upper and lower work rolls on the stand entrance side in the fifth embodiment. It is assumed that the processing content is read. In the fourth embodiment, in S4 of FIG.
When it is determined that Δt _d > 0, the precoat application device is operated to apply high-concentration oil to the upper and lower surfaces of the steel plate at the upstream side of the stand. If the possibility of chattering is low when Δt _d > 0, the precoat apparatus is not operated.

Embodiment 5 FIG. FIG. 8 is a configuration diagram of a rolling mill according to Embodiment 5 of the present invention, and 1 to 7, 9, 10, and 17 in FIG. 8 are the same as those in FIG. Reference numeral 19 denotes a roll precoat nozzle, and reference numeral 20 denotes a lubrication nozzle. In the fifth embodiment shown in FIG. 8, high-concentration oil is stored in the pre-coat tank 17 in the same manner as in FIG. This is a processing method of applying high-concentration oil to a roll and performing cold rolling.

Embodiment 6 FIG. FIG. 10 shows Embodiment 6 of the present invention.
Is a configuration diagram of a rolling mill according to the present invention, and 1-4, 7 and 9 in the drawing are the same as those in FIG. 21 is a coolant tank, 22
Is a flow system control valve, and 23 is a cooling nozzle. In the coolant tank 21, water and oil are mixed and an emulsion-like coolant is stored. A required number of cooling nozzles 23 are provided for cooling the steel sheet and for cooling the roll, respectively, and an individual flow control valve 22 is provided on the input side of each cooling nozzle. In the embodiment of FIG. 10, each flow control valve 22 of the steel plate cooling nozzle and the roll cooling nozzle 23 is controlled based on a command of the calculation device 7 in the figure. FIG. 9 is a flowchart showing the processing sequence of the high-speed cold rolling method according to Embodiment 6 of the present invention, and the processing of step numbers S1 to S3 in the figure is the same as that in FIG. In S4 of FIG. 9, when Δt _d > 0 is determined in S3, the flow rate control valves of the steel plate cooling nozzle and the roll cooling nozzle are controlled to control the flow rates of the coolant to the steel plate and the roll. When chattering is unlikely to occur when Δt _d <0, lubricating oil at a normal flow rate is supplied.

Next, the result of rolling with the rolling mill configuration according to the sixth embodiment shown in FIG. 10 will be described. Table 1 below shows steel types, dimensions, rolling schedules, and lubricating oil types used.

[0047]

[Table 1]

In the case of a normal rolling method not according to the present invention,
Chattering occurs at a rolling speed of 1450 mpm. However, according to the sixth embodiment, based on the calculation flow of FIG. 9, the supply flow rate of the steel plate cooling and the roll cooling on the entrance side of the # 5 stand is controlled from the flow rate of 40000 l / min in a normal rolling method to 2000 l / min. The operation at a maximum speed of the rolling mill of 1850 mpm became possible. FIG.
In addition, when the sixth embodiment is applied to a tin plate material having a steel type (equivalent to T4CA and T5CA) and dimensions (cold rolled finished plate thickness: 0.24 mm or less) in which chattering is a problem during high-speed rolling. The relation between the sheet thickness and the rolling speed at the time is shown. According to this figure, it can be seen that the rolling speed is remarkably improved at a plate thickness of 0.20 mm or less, at which the rolling speed could not be increased particularly conventionally.

Embodiment 7 FIG. In the seventh embodiment of the present invention, as described above, the processing of the first to sixth embodiments is performed by one or both of the last stand, which is frequently used as a chattering trigger stand, and the immediately preceding stand. This embodiment is designed to prevent chattering from occurring, and the seventh embodiment is already shown in FIGS. 2, 4, 5, 7, 8, and 10.

[0050]

As described above, according to the present invention, in a cold rolling method using a tandem rolling mill for a steel sheet, a steel sheet temperature, a work roll temperature, a rolled sheet speed, and a work roll rolling rate during rolling are measured, respectively. An estimated value of the amount of lubricating oil introduced is calculated based on these measured values, and the estimated value of the calculated amount of lubricating oil introduced and the amount of lubricating oil introduced when chattering occurs in the high-speed rolling zone determined in advance. Compare with the lower limit, if the estimated value is less than or equal to this lower limit,
(1) The amount of lubricating oil supplied to the lubricating oil system is controlled so that the estimated value of the amount of lubricating oil introduced is equal to or greater than the lower limit, or (2) lubricating oil of normal concentration or normal viscosity is supplied. Switching from a lubricating oil system to a lubricating oil system that supplies high-concentration or high-viscosity lubricating oil, or using the two lubricating oil systems in parallel, (3) Apply high-concentration oil to the upper and lower work rolls or the upper and lower work rolls on the stand entry side,
(4) Since the flow rate of the coolant for cooling the work roll and the steel sheet is controlled, it is possible to prevent the occurrence of chattering due to insufficient lubrication in the conventional high-speed rolling zone, and to reduce the speed of hard / thin gauge material. The effect that rolling and high productivity can be realized is obtained.

According to the present invention, in the cold rolling method using a tandem rolling mill for a steel sheet, the processing method according to any one of the above (1) to (4) is applied to the final step which frequently serves as a trigger stand for chattering. Since the operation is performed on one or both of the stand and the immediately preceding stand, an effect is obtained that chattering can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing sequence of a high-speed cold rolling method according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a rolling mill according to Embodiment 1 of the present invention.

FIG. 3 is a flowchart showing a processing sequence of a high-speed cold rolling method according to Embodiments 2 and 3 of the present invention.

FIG. 4 is a configuration diagram of a rolling mill according to Embodiment 2 of the present invention.

FIG. 5 is a configuration diagram of a rolling mill according to Embodiment 3 of the present invention.

FIG. 6 is a flowchart showing a processing order of a high-speed cold rolling method according to Embodiments 4 and 5 of the present invention.

FIG. 7 is a configuration diagram of a rolling mill according to Embodiment 4 of the present invention.

FIG. 8 is a configuration diagram of a rolling mill according to Embodiment 5 of the present invention.

FIG. 9 is a flowchart showing a processing sequence of a high-speed cold rolling method according to Embodiment 6 of the present invention.

FIG. 10 is a configuration diagram of a rolling mill according to Embodiment 6 of the present invention.

FIG. 11 is a view showing measurement results of an oil pit ratio on a steel sheet surface when chattering occurs and during stable rolling.

FIG. 12 is a diagram showing the relationship between the rolling speed and the amount of oil adhering to the steel sheet surface.

FIG. 13 is a diagram showing a relationship between a steel sheet / roll cooling flow rate and a rolling speed when chattering occurs.

FIG. 14: 5-stage stand, tandem mill, rear stage # 3-
It is a figure which shows the example of a measurement of the vibration accelerometer in the housing of # 5 stand.

FIG. 15 is a diagram showing a relationship between a plate-out amount and a steel plate temperature.

FIG. 16 is a diagram showing a relationship between a plate-out amount and a rolling oil concentration.

FIG. 17 is a diagram showing a relationship between a plate-out amount and an emulsion particle size of rolling oil.

FIG. 18 is a diagram showing a relationship between a plate-out amount and a spray time.

FIG. 19 is a diagram showing a relationship between a friction coefficient and a steel sheet temperature.

FIG. 20 is a diagram showing a relationship between a sheet thickness and a rolling speed when Embodiment 6 of the present invention is applied and when it is not applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolled plate 2A Plate thermometer 2B Roll thermometer 3 Plate speed meter 4 Tachometer 5 Flow meter 6 Pressure control valve 7 Calculation device 8 Coolant control valve control device 9 Pump 10 Lubricating oil tank

────────────────────────────────────────────────── (5) References JP-A-62-72409 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 45/02 B21B 37/18 B21B 27 / Ten

Claims (5)

(57) [Claims] In a cold rolling method using a tandem rolling mill for a steel sheet, a temperature of a steel sheet during rolling, a work roll temperature, a rolled sheet speed and a work roll rolling speed are measured, and a lubricating oil introduction oil is determined based on the measured values. The estimated value of the amount of lubricating oil introduced is calculated and the calculated estimated value of the amount of introduced lubricating oil is compared with a previously determined high-speed rolling zone (oil pit area ratio is 50% or less).
And the lower limit of the amount of lubricating oil introduced when chattering occurs at a rolling speed of 1000 mpm or more) , and when the above estimated value falls below this lower limit, the amount of lubricating oil introduced is reduced. A high-speed cold rolling method, wherein the amount of oil supplied to the lubricating oil system is controlled so that the estimated value is equal to or greater than the lower limit. 2. In a cold rolling method using a tandem rolling mill for a steel sheet, a steel sheet temperature during rolling, a work roll temperature, a rolled sheet speed, and a work roll rolling speed are measured, and a lubricating oil introduction oil is determined based on the measured values. The estimated value of the amount of lubricating oil introduced is calculated and the calculated estimated value of the amount of introduced lubricating oil is compared with a previously determined high-speed rolling zone (oil pit area ratio is 50% or less).
In the region where the rolling speed is 1000 mpm or more) , the chattering is compared with the lower limit of the amount of lubricating oil introduced when chattering occurs. A high-speed cold rolling method characterized by switching from a lubricating oil system for supplying a lubricating oil to a lubricating oil system for supplying a high-concentration or high-viscosity lubricating oil, or using the two lubricating oil systems in parallel. 3. In a cold rolling method using a tandem rolling mill for a steel sheet, a temperature of a steel sheet during rolling, a work roll temperature, a rolled sheet speed and a work roll rolling speed are measured, and a lubricating oil introduction oil is determined based on the measured values. The estimated value of the amount of lubricating oil introduced is calculated and the calculated estimated value of the amount of introduced lubricating oil is compared with a previously determined high-speed rolling zone (oil pit area ratio is 50% or less).
In the region where the rolling speed is 1000 mpm or more) , the lower limit value of the amount of lubricating oil introduced when chattering occurs is compared with the lower limit value. A high-speed cold rolling method characterized by applying high-concentration oil to upper and lower surfaces of a steel plate or upper and lower work rolls on the side of a stand. 4. In a cold rolling method using a tandem rolling mill for a steel sheet, a steel sheet temperature during rolling, a work roll temperature, a rolled sheet speed, and a work roll rolling speed are measured, and a lubricating oil introduction oil is determined based on the measured values. The estimated value of the amount of lubricating oil introduced is calculated and the calculated estimated value of the amount of introduced lubricating oil is compared with a previously determined high-speed rolling zone (oil pit area ratio is 50% or less).
In the region where the rolling speed is 1000 mpm or more) , the lower limit of the amount of lubricating oil introduced when chattering occurs is compared with the lower limit of the lubricating oil introduction oil. A high-speed cold rolling method characterized by controlling a coolant flow rate to be performed. 5. A high-speed cold rolling method according to any one of claims 1 to 4, wherein the high-speed cold rolling method according to any one of claims 1 to 4 is applied to one of a final stand and a preceding stand. A high-speed cold rolling method performed on one or both of them.