JP6750487B2 - Rolling oil supply equipment and rolling oil supply method - Google Patents

Description

The present invention relates to a rolling oil supply facility and a rolling oil supply method in cold rolling.

In cold rolling, for the purpose of stabilizing the rolling operation, improving the shape quality of the product, improving the surface quality by preventing seizure, etc., and prolonging the life of the roll, Lubricating oil (rolling oil) is supplied to the rolled material and work rolls on the inlet side of the rolling mill in order to maintain the friction coefficient between them at an appropriate value. Here, the seizure is a phenomenon in which the rolled material and the work roll come into direct contact with each other due to insufficient lubrication between the rolled material and the work roll. The seizure can cause a flaw on the surface of the rolled material called heat scratch.

Here, in cold rolling, the lubrication state between the rolled material and the work rolls changes according to the acceleration and deceleration of the rolling speed. Therefore, in order to keep the lubrication state in a desired state when the rolling speed changes, it is necessary to control the supply state of rolling oil according to the change in the rolling speed and change the lubrication state.

Also, the desired lubrication state between the rolled material and the work rolls differs depending on the type of rolled material and the like. For example, for rolling materials that are prone to seizure, it is necessary to improve lubrication. For products with strict surface quality requirements, if the amount of rolling oil supplied is too large, the rolling oil itself may cause defects. It may become. Therefore, in cold rolling, it is required to control the supply state of rolling oil and change the lubrication state depending on the type of rolled material.

As described above, in cold rolling, the supply state of rolling oil is dynamically controlled during rolling in accordance with rolling conditions (for example, rolling speed, type of rolled material, etc.), and plate-out control (rolled material is performed). It is required to change the lubrication state by controlling the degree of adhesion of rolling oil to the surface of the.

Here, in the cold rolling, it is general to supply, as the rolling oil, a so-called emulsion, for example, a rolling oil having a concentration ratio of about 1 to 2 (%) emulsified in water. Then, usually, an emulsion having a predetermined concentration is stored in a tank (emulsion tank), and the emulsion in the emulsion tank is often supplied. Therefore, when trying to dynamically change the concentration of the emulsion when trying to change the lubrication state, it is not possible to immediately change the concentration of the emulsion in the emulsion tank, and it is difficult to control with high response. In addition, when trying to change the lubrication state, even if the emulsion supply amount is controlled dynamically, the amount of rolling oil supplied itself changes dramatically because the emulsion concentration is relatively low. Therefore, it is difficult to control the lubrication state with high sensitivity.

Therefore, with the device for supplying the emulsion, a device for separately supplying the rolling oil stock solution is separately installed, and a technology for additionally supplying the rolling oil stock solution when further lubrication is required while constantly supplying the emulsion is disclosed. (For example, Patent Document 1). According to such a technique, the rolling oil stock solution can be directly supplied as needed, so that the lubrication state can be changed to high sensitivity and high response. It should be noted that such lubrication performed by additionally supplying a higher concentration of rolling oil to the emulsion lubrication is called semi-direct lubrication.

Further, in the technique described in Patent Document 1, an electrostatic coating device is applied as a facility for supplying a stock solution of rolling oil. The electrostatic coating device is used to charge rolling oil and generate a potential difference between the rolling oil and the rolling material and/or work rolls, so that the rolling oil is rolled and/or working by the electrostatic force due to the potential difference. This is a device for adhering to a roll (for example, Patent Document 2). According to the electrostatic coating device, since the rolling oil can be attached to the rolling material and/or the work roll by the electrostatic force, the adhesiveness of the rolling oil is improved, and even if the rolling oil has a low viscosity, for example, it can be efficiently used. It becomes possible to obtain a good lubrication state. As described above, in the technique described in Patent Document 1, it is possible to change the lubrication state with higher response and high sensitivity by using the electrostatic coating device to supply the rolling stock solution.

JP, 2014-36979, A JP-A-57-137021

However, in the technique described in Patent Document 1, the rolling oil supply equipment is configured such that the emulsion supply nozzle (emulsion nozzle) is located downstream of the electrostatic coating device in the rolling direction. Accordingly, even if the rolling oil stock solution is electrostatically applied to the rolled material by the electrostatic coating device, the emulsion is supplied downstream from the rolling stock solution, so that the rolling stock solution is washed away by the emulsion. The lubrication effect due to the application of is reduced. Therefore, in the technique described in Patent Document 1, even if the rolling oil stock solution is electrostatically applied to obtain better lubrication, the lubrication state may not be efficiently changed.

It should be noted that such a problem is solved by reversing the installation positions of the electrostatic coating device and the emulsion nozzle in the rolling direction (that is, by positioning the emulsion nozzle on the upstream side of the electrostatic coating device in the rolling direction). there is a possibility. However, generally, in a rolling oil supply facility in cold rolling, an emulsion nozzle is often provided immediately in front of a rolling mill so that the emulsion can be directly sprayed onto a rolling material and work rolls. Therefore, if an electrostatic coating device is additionally installed to the existing rolling oil supply equipment, the electrostatic coating device must be installed upstream of the emulsion nozzle. If you try to configure the rolling oil supply equipment so that the emulsion nozzle is located on the upstream side of the electrostatic coating device in the rolling direction, it is necessary to remodel the existing rolling oil supply equipment drastically, which is not practical in terms of cost. ..

In view of the above circumstances, in rolling oil supply equipment that supports semi-direct lubrication, there has been a demand for a technology that enables more efficient change of the lubrication state during rolling. Therefore, the present invention has been made in view of the above problems, the object of the present invention, in cold rolling, it is possible to more efficiently change the lubricating state during rolling, novel and An object of the present invention is to provide an improved rolling oil supply facility and rolling oil supply method.

In order to solve the above problems, according to an aspect of the present invention, an emulsion supply device that supplies an emulsion to a work roll of a rolling material and the rolling mill on the inlet side of a rolling mill, and more than the emulsion supply device. On the upstream side in the rolling direction, an electrostatic coating device for electrostatically coating a rolling oil stock solution on the rolled material, and a control device for controlling the operations of the emulsion supply device and the electrostatic coating device, A control device is provided with rolling oil supply equipment, which stops the supply of emulsion by the emulsion supply device when the rolled material electrostatically coated with the rolling oil stock solution by the electrostatic coating device is being rolled. ..

The rolling oil supply facility further includes a cooling mechanism that cools at least one of the rolled material and the work roll under the control of the control device, and the control device includes the electrostatic coating device. A rolling oil stock solution is electrostatically applied to a rolled material, and when the emulsion supply by the emulsion supply device is stopped, at least one of the rolled material and the work roll is cooled by the cooling mechanism. Good.

In the rolling oil supply facility, the cooling mechanism may be a rolled material cooling device that sprays cooling water on the rolled material on the upstream side of the electrostatic coating device in the rolling direction.

Further, in the rolling oil supply facility, the cooling mechanism may be a roll cooling device that injects cooling water to the work rolls on the exit side of the rolling mill.

Further, in the rolling oil supply equipment, the control device, while supplying the emulsion by the emulsion supply device, calculates the friction coefficient between the rolled material and the work roll, the calculated friction When the coefficient exceeds a predetermined threshold value, electrostatic coating of the rolling oil stock solution by the electrostatic coating device may be started and supply of the emulsion by the emulsion supply device may be stopped.

Further, in the rolling oil supply equipment, the control device, while supplying the emulsion by the emulsion supply device, calculates the oil film thickness immediately below the roll bite, and the calculated oil film thickness is a predetermined threshold value. When it is below the range, electrostatic coating of the rolling oil stock solution by the electrostatic coating device may be started and supply of the emulsion by the emulsion supply device may be stopped.

Further, in the rolling oil supply equipment, the control device, while supplying the emulsion by the emulsion supply device, the temperature of the rolled material measured on the exit side of the rolling mill, or by the control device. When the temperature of the rolled material just below the calculated roll bite exceeds a predetermined threshold value, electrostatic coating of the rolling oil stock solution by the electrostatic coating device is started, and the emulsion is supplied by the emulsion supply device. You may stop it.

Further, in order to solve the above problems, according to another aspect of the present invention, by using the rolling oil supply facility, at least control the operation of the emulsion supply device and the electrostatic coating device dynamically during rolling. A method for supplying rolling oil is provided.

As described above, according to the present invention, in cold rolling, the lubrication state can be changed more efficiently during rolling.

It is a figure showing an example of composition of rolling oil supply equipment concerning this embodiment. It is a figure which shows one structural example of the rolling oil stock solution nozzle of an electrostatic coating device. It is a figure for demonstrating the threshold value of a friction coefficient. It is a graph figure which shows the transition of the friction coefficient between the steel plate and the work roll during rolling in the experiment using the testing machine which imitated the rolling oil supply equipment which concerns on this embodiment. It is a flow figure showing an example of the processing procedure of the rolling oil supply method concerning this embodiment. It is a figure which shows one structural example of the rolling oil supply equipment which concerns on the modification which uses the oil film thickness just under a roll bite as an index which shows a lubrication state. In the experiment which used the test machine which imitated the rolling oil supply equipment 2 which concerns on the modification which uses the oil film thickness immediately under a roll bite as an index which shows a lubrication state, it is a graph showing the change of the oil film thickness immediately under a roll bite during rolling is there. It is a figure which shows one structural example of the rolling oil supply equipment which concerns on the modification which uses the strip temperature at the rolling mill exit side as an index which shows a lubrication state. Shows the transition of the plate temperature on the rolling mill outlet side during rolling in an experiment using a tester simulating a rolling oil supply facility according to a modification that uses the plate temperature on the rolling mill outlet side as an index indicating the lubrication state It is a graph figure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(1. Configuration of rolling oil supply equipment)
With reference to Drawing 1, the composition of rolling oil supply equipment concerning one suitable embodiment of the present invention is explained. FIG. 1 is a diagram showing a configuration example of rolling oil supply equipment according to the present embodiment.

FIG. 1 shows a configuration example in which the rolling oil supply equipment 1 according to the present embodiment is applied to a rolling mill 110 for cold rolling. The rolling mill 110 has a pair of upper and lower work rolls 111 and 112, and backup rolls 113 and 114 installed above and below the work rolls 111 and 112 and supporting the work rolls 111 and 112, respectively. As described above, the rolling mill 110 has a so-called quadruple rolling mill configuration including four rolls. The interval (roll gap) between the work rolls 111 and 112 in the rolling mill 110 is appropriately adjusted according to the rolling conditions, and the steel sheet 10 as a rolled material is thinly extended by passing through the rolling mill 110, It can be processed to have a desired plate thickness.

Note that, in FIG. 1, for simplification, of the configuration of the rolling mill 110, only the configuration necessary for explaining the rolling oil supply facility 1 according to the present embodiment is mainly illustrated. In practice, the rolling mill 110 may have various configurations included in a general rolling mill for cold rolling, other than the configuration shown in the drawing. Various commonly known configurations can be applied to the configurations not shown in the drawings, and thus the description thereof will be omitted. In addition, various known methods may be used for controlling the rolling mill 110 during rolling, such as the rolling position and roll speed, and thus description thereof will be omitted.

Further, in FIG. 1, for the sake of explanation, only one rolling mill 110 in the tandem cold rolling line is shown. Actually, a plurality of rolling mills 110 are continuously installed in series to configure a tandem cold rolling line, and the rolling oil supply facility 1 according to the present embodiment is provided for each rolling mill 110. Can be done.

The rolling oil supply facility 1 according to the present embodiment includes an emulsion supply device 120 that supplies emulsion to the steel plate 10 and the work rolls 111 and 112 of the rolling mill 110 on the inlet side of the rolling mill 110, and a rolling direction that is greater than the emulsion supply device 120. In the above, the electrostatic coating device 130 for electrostatically applying the rolling stock solution to the steel plate 10, the rolling load meter 140 for measuring the rolling load in the rolling mill 110, and the outlet side of the rolling mill 110 are installed. A plate speedometer 150 that measures the speed of the steel plate 10, a grounding device 162 that is attached to a tension roll 161 that measures the tension applied to the steel plate 10, and grounds the steel plate 10 via the tension roll 161, and an electrostatic coating device 130. A steel plate cooling device 170 that is installed on the upstream side in the rolling direction to cool the steel plate 10, and a control device 180 that controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170.

(Rolling load meter and strip speed meter)
As the rolling load meter 140 and the plate speed meter 150, various known materials can be used. The rolling load meter 140 and the strip speed meter 150 sequentially transmit the measured rolling load and strip speed to the control device 180 at predetermined intervals.

(Grounding device)
The grounding device 162 has a function of grounding the steel plate 10. Generally, in cold tandem rolling, since rolling is performed while controlling tension between stands, a device such as a tension roll 161 for measuring tension between stands can be provided. The grounding device 162 grounds the steel plate 10 via the tension roll 161. However, such a configuration is merely an example, and the grounding device 162 only needs to be able to ground the steel plate 10, and the specific grounding method is not limited. The grounding device 162 may ground the steel plate 10 via another member provided in contact with the steel plate 10.

(Steel plate cooling device)
The steel plate cooling device 170 cools the steel plate 10 by injecting cooling water onto the steel plate 10 under the control of the control device 180. However, the steel plate cooling device 170 has only to have a function of cooling the steel plate 10, and its specific device configuration is not limited. As the steel plate cooling device 170, various known devices may be used.

(Emulsion supply device)
The emulsion supply device 120 is installed on the entrance side of the rolling mill 110 and the emulsion tank 122 that stores the emulsion, and the emulsion nozzle 121 that supplies the emulsion in the emulsion tank 122 to the work rolls 111 and 112 of the steel plate 10 and the rolling mill 110. And, mainly. The emulsion stored in the emulsion tank 122 has a concentration of, for example, about 1 to 2 (%) and is generally used for lubrication in cold rolling. In the present embodiment, the presence/absence of emulsion supply is appropriately switched under the control of the control device 180. At this time, the concentration and the supply amount of the emulsion to be supplied may be predetermined conditions generally used in cold rolling. In FIG. 1, in order to show that the supply of the emulsion is controlled by the control device 180, for convenience, a valve 123 provided in the flow path between the control device 180 and the emulsion tank 122 and the emulsion nozzle 121. And are connected by a line.

As the emulsion supply device 120, various commonly used ones can be applied. For example, as the emulsion supply device 120, the one described in Patent Document 1 may be applied. For example, although not shown in FIG. 1, the emulsion supply device 120 may be provided with a circulation mechanism for collecting and reusing the supplied emulsion, as described in Patent Document 1 above.

(Electrostatic coating device)
The electrostatic applicator 130 supplies the undiluted solution of rolling oil to the steel plate 10 to apply the undiluted solution of rolling oil to the steel plate 10 by electrostatic force. The electrostatic coating device 130 is installed on the rolling oil stock solution storage tank 132 that stores the rolling oil stock solution, and on the inlet side of the rolling mill 110 and on the upstream side of the emulsion nozzle 121. And an electrostatic coating nozzle 131 for supplying the rolling oil stock solution.

The configuration of the electrostatic coating nozzle 131 of the electrostatic coating device 130 will be described in detail with reference to FIG. FIG. 2 is a diagram showing a configuration example of the electrostatic coating nozzle 131 of the electrostatic coating device 130.

As shown in FIG. 2, the electrostatic coating nozzle 131 has a charging port 134 into which the rolling oil stock solution is fed from the rolling oil stock solution storage tank 132, and an openable/closable injection port 135 for injecting the rolling oil stock solution. An air introduction port 138 that is provided at the end opposite to the ejection port 135 and that introduces air into the electrostatic coating nozzle 131 is provided. The rolling oil stock solution is injected from the injection port 135 by introducing air from the air introduction port 138 while introducing the rolling oil stock solution from the input port 134.

Further, the electrostatic coating nozzle 131 is provided with a low-current DC high-voltage power supply 136 for applying a high voltage to the rolling oil stock solution introduced into the electrostatic coating nozzle 131. In addition, a pair of dielectric rods (induct bar) 137 for generating a strong electric field are provided near the injection port 135.

In the electrostatic coating device 130, the rolling oil stock solution charged from the charging port 134 is charged inside the electrostatic coating nozzle 131 by the low current DC high voltage power supply 136. The charged rolling oil stock solution forms electrostatically charged particles by electrostatic charge, and each particle repels each other because it has the charge of the same electrode. Further, air is introduced from the air introduction port 138, and as a result, rolling is performed from the injection port 135. Particles of oil stock solution jump out. The particles of the undiluted rolling oil solution that have jumped out are decomposed into smaller particles that have been charged due to the influence of a strong electric field generated by the dielectric rod 137, and the charges held by these particles repel each other to form a mist. Since the injection port 135 is open toward the surface of the steel plate 10, the atomized fine particles of the rolling oil stock solution are injected toward the surface of the steel plate 10.

Since the steel plate 10 is grounded by the grounding device 162 as described above, the charged fine particles of the undiluted rolling oil solution are adsorbed to the steel plate 10 to lose the electric charge. In this way, the rolling oil stock solution is adsorbed on the surface of the steel sheet 10 by the electrostatic coating device 130.

The control device 180 controls the drive of the electrostatic coating device 130 described above, and controls the electrostatic coating of the rolling oil stock solution onto the steel plate 10. Specifically, the control device 180 controls the supply amount of the rolling oil stock solution to the input port 134, and according to the supply amount, the voltage applied by the low-current DC high-voltage power supply 136 and the strength of the electric field by the dielectric rod 137. The amount of adsorption of the stock solution of rolling oil to the steel plate 10, that is, the amount of application is appropriately adjusted by controlling Note that, in FIG. 1, in order to show that the control device 180 controls the electrostatic coating of the rolling oil stock solution by the electrostatic coating device 130, for convenience, the control device 180, the rolling oil stock solution storage tank 132, and the electrostatic coating device 132 are illustrated. The electrostatic coating nozzle 131 of the coating device 130 and the valve 133 provided in the flow path between them are shown connected by a line.

As the electrostatic coating device 130, various commonly used ones can be applied. For example, as the electrostatic coating device 130, the one described in Patent Document 1 may be applied.

(Control device)
The control device 180 controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 to dynamically control the lubrication state between the steel plate 10 and the work rolls 111 and 112 during rolling. change. In the present embodiment, the coefficient of friction between the steel plate 10 and the work rolls 111 and 112 is used as an index indicating the lubrication state. The control device 180 controls the operation of each device based on the friction coefficient.

Specifically, the control device 180 does not operate the electrostatic coating device 130 and the steel plate cooling device 170 at the start of rolling, and only causes the emulsion supply device 120 to supply the emulsion. At this time, as described above, the concentration and the amount of the emulsion to be supplied may be in accordance with predetermined conditions generally used in cold rolling. As described above, at this time, the control device 180 does not operate the steel plate cooling device 170, but the emulsion plays a role of cooling the steel plate 10 and the work rolls 111 and 112 while supplying the emulsion. Therefore, even if the steel plate cooling device 170 is not operated, the steel plate 10 and the work rolls 111 and 112 are less likely to be excessively heated.

In this state, the control device 180 uses the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 to calculate the steel plate 10 and the work rolls 111 and 112 according to the theoretical rolling model. Calculate the friction coefficient between them. Since the method of calculating the friction coefficient is publicly known, its detailed description is omitted here.

Then, control device 180 determines whether the calculated friction coefficient is less than or equal to a predetermined threshold value. Here, the threshold value is an upper limit value of a desirable range of the friction coefficient that does not cause defects such as seizure due to insufficient lubrication according to rolling conditions, for example, results of experiments and simulations, and past values. It is determined as appropriate based on the operational performance data, etc.

FIG. 3 is a diagram for explaining the threshold value of the friction coefficient. FIG. 3 shows the result of an experiment conducted to determine the threshold value of the friction coefficient. In the experiment, the lubrication conditions were variously changed during rolling of the steel sheet, the friction coefficient during the rolling was calculated at any time, and the occurrence of seizure in the steel sheet was investigated. In FIG. 3, the horizontal axis represents the time during rolling and the vertical axis represents the calculated friction coefficient, which shows the change over time in the friction coefficient during rolling.

As shown in FIG. 3, in the experiment, it was confirmed that seizure occurred when the friction coefficient exceeded a certain value μ ₁ . Therefore, under the rolling conditions according to the experiment, the threshold value (upper limit value) of the friction coefficient that does not cause defects is μ ₁ . In the present embodiment, the same experiment is performed while variously changing the rolling conditions, the threshold value of the friction coefficient is determined in advance for each rolling condition, and stored in a storage device (not shown in FIG. 1). Keep it. By referring to the storage device, the control device 180 sets a threshold value of the friction coefficient that matches the rolling condition of the rolling currently controlled, and uses the threshold value to perform the above determination process. It can be carried out.

If the calculated friction coefficient is less than or equal to the threshold value as a result of the above determination process, it indicates that the current lubrication state is in a good state in which no defects occur. Therefore, in this case, the control device 180 does not perform special control.

On the other hand, when the calculated friction coefficient exceeds the threshold value, it indicates that the current lubrication state is a state in which lubrication may be insufficient and a defect may occur. Therefore, in this case, in order to improve the lubrication state, the control device 180 operates the electrostatic coating device 130 so that the friction coefficient is equal to or less than the threshold value, and the rolling oil stock solution is kept static. Start electrocoating.

Here, as described above, even if an attempt is made to change the lubrication state by adjusting the concentration and the supply amount of the emulsion supplied by the emulsion supply device 120, it is possible to change the lubrication state with high response and high sensitivity. Have difficulty. Therefore, as described above, in the present embodiment, the supply path of the rolling oil stock solution is prepared as a supply path of a system different from the supply path of the emulsion, and the supply of the rolling oil stock solution is controlled to provide lubrication. Change the state. By using the rolling oil stock solution, it becomes possible to change the lubrication state with higher sensitivity and higher response. Further, at this time, the rolling oil stock solution is electrostatically applied to the steel sheet 10 using the electrostatic application device 130. By using the electrostatic coating device 130, the adhesion of the rolling oil stock solution to the steel plate 10 can be further improved, so that the lubrication state can be changed to have higher sensitivity and higher response.

Further, the control device 180 starts the electrostatic coating of the rolling oil stock solution by the electrostatic coating device 130, and then stops the emulsion supply by the emulsion supply device 120. If the emulsion is also supplied while electrostatically applying the rolling oil stock solution by the electrostatic coating device 130, the rolling oil stock solution on the surface of the steel sheet 10 is washed away by the supplied emulsion, and the lubricating effect of the rolling oil stock solution is obtained. A situation may occur in which the Therefore, in the present embodiment, as described above, the supply of the emulsion is stopped while the rolling oil stock solution is electrostatically applied. As a result, it is possible to more appropriately obtain the lubrication effect by applying the rolling oil stock solution, and it is possible to more efficiently reduce the friction coefficient. As described above, according to this embodiment, the effect of semi-direct lubrication can be more suitably exhibited.

However, if the emulsion supply is stopped at the same time when the electrostatic application of the rolling oil stock solution is started, the rolling oil is not supplied to the steel plate 10 between the position where the rolling oil stock solution is applied and the emulsion supply position. turn into. Therefore, in the present embodiment, the control device 180 starts the electrostatic application of the rolling oil stock solution for a predetermined time (specifically, so that the area where the rolling oil is not supplied cannot exist on the surface of the steel plate 10). Specifically, the emulsion supply device 120 and the electrostatic coating are applied so that the supply of the emulsion is stopped at least after the elapse of a time period at which the rolling oil stock solution has been applied on the steel plate 10 has passed). The device 130 is operated. In other words, in other words, the control device 180 stops the supply of the emulsion while the steel sheet 10 electrostatically coated with the rolling oil stock solution is being rolled. The predetermined time may be calculated and set as appropriate according to the rolling speed and the like.

Further, the control device 180 operates the steel plate cooling device 170 after stopping the supply of the emulsion, and starts cooling the steel plate 10. As described above, the emulsion has a role of supplying the rolling oil and a role of cooling the steel plate 10 and the work rolls 111 and 112. Therefore, if the supply of the emulsion is stopped while the rolling oil stock solution is electrostatically applied, the steel plate 10 and the work rolls 111 and 112 are heated, which may promote the occurrence of seizure. Therefore, in the present embodiment, as described above, after the supply of the emulsion is stopped, the steel plate cooling device 170 cools the steel plate 10. This makes it possible to appropriately cool the steel plate 10 and the work rolls 111 and 112 even when the supply of the emulsion is stopped. Note that the control device 180 may operate the steel plate cooling device 170 at substantially the same time as when the supply of the emulsion is stopped, or in a range in which the temperature increase of the steel plate 10 and the work rolls 111 and 112 does not occur. It may be after an arbitrary time has passed since the supply of the emulsion was stopped.

After the start of rolling, the controller 180 supplies the emulsion, and while the emulsion is being supplied, every time the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 are transmitted, the friction coefficient described above is transmitted. And the process of determining whether or not the friction coefficient is less than or equal to the threshold value are sequentially executed. Then, the control device 180 appropriately executes the above-described control of the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 according to the determination result.

Here, the coating amount of the rolling oil stock solution when the control device 180 operates the electrostatic coating device 130 can be set by the following method, for example. For example, the correlation between the coating amount of the rolling oil stock solution applied to the steel sheet 10 by electrostatic coating and the friction coefficient between the steel sheet 10 and the work rolls 111 and 112 is acquired in advance by an experiment or a simulation, and the table And the like are stored in the storage device. Then, the control device 180 refers to the storage device and uses the correlation between the coating amount of the rolling oil stock solution on the steel plate 10 and the friction coefficient, so that the friction coefficient can be changed by a desired amount. The coating device 130 may be operated appropriately.

However, at this time, as shown in FIG. 4 described later, even if the amount of the undiluted rolling oil applied to the steel plate 10 is constant, the value of the friction coefficient changes depending on whether or not the emulsion is supplied. Therefore, when operating the electrostatic coating device 130, it is necessary to determine the coating amount of the rolling oil stock solution by the electrostatic coating device 130 in consideration of the change in the friction coefficient accompanying the suspension of the emulsion supply. .. Specifically, for example, data about the rate of change of the friction coefficient between the steel plate 10 and the work rolls 111 and 112 accompanying the suspension of the emulsion supply is acquired in advance, and the electrostatic coating device 130 is used. When determining the operating conditions of the above, not only the correlation between the amount of the rolling oil stock solution applied to the steel sheet 10 and the friction coefficient described above, but also the data is used to change the friction coefficient accompanying the suspension of the emulsion supply. In consideration of the above, the application amount of the rolling oil stock solution by the electrostatic application device 130 may be determined so that the friction coefficient can be changed by a desired amount.

Also, regarding the cooling amount of the steel plate 10 when the control device 180 operates the steel plate cooling device 170, similarly, the cooling amount of the steel plate 10 by the steel plate cooling device 170 (for example, specifically, The correlation between the flow rate of cooling water to be injected) and the temperature decrease amount of the steel plate 10 may be acquired in advance and stored in the storage device in the form of a table or the like. The control device 180 refers to the storage device and uses the correlation between the cooling amount of the steel plate 10 by the steel plate cooling device 170 and the temperature decrease amount of the steel plate 10, whereby the temperature of the steel plate 10 causes a defect such as seizure. The steel plate cooling device 170 may be appropriately operated so that it falls within a desired range that is not allowed.

However, when the temperature of the steel plate 10 changes, the lubrication state between the steel plate 10 and the work rolls 111 and 112, that is, the friction coefficient may also change. This is because if the temperature of the steel sheet 10 changes, the temperature of the rolling oil on the surface of the steel sheet 10 also changes, and the viscosity of the rolling oil changes. Therefore, when operating the electrostatic coating device 130, it is necessary to determine the coating amount of the rolling oil stock solution by the electrostatic coating device 130, further considering the change in the friction coefficient with the temperature change of the steel plate 10. .. Specifically, for example, the correlation between the cooling amount of the steel plate 10 by the steel plate cooling device 170 and the coefficient of friction between the steel plate 10 and the work rolls 111 and 112 is acquired in advance, and the electrostatic coating device 130 is used. When determining the operating conditions of the above, not only the correlation between the coating amount of the rolling stock solution to the steel plate 10 and the friction coefficient described above, but also the correlation between the cooling amount of the steel plate 10 by the steel plate cooling device 170 and the friction coefficient is used. Then, in consideration of the change in the friction coefficient due to the temperature decrease of the steel plate 10 by the steel plate cooling device 170, the application amount of the rolling oil stock solution by the electrostatic application device 130 such that the friction coefficient can be changed by a desired amount is determined. Good.

Here, the present inventors conducted the following experiment in order to confirm the effect of applying the rolling oil supply equipment 1. The present inventors created a test machine that mimics the configuration in which the rolling oil supply facility 1 is provided for the rolling mill 110 described above, and performs rolling on a steel plate (coil) while In order to simulate the rolling oil supply method, the rolling oil supply equipment was operated in the order of A to D below. Then, during this rolling, the coefficient of friction between the steel plate and the work roll was sequentially calculated from the measured value of the rolling load and the measured value of the plate speed, and the transition of the friction coefficient during rolling was investigated.

A: Emulsion only is supplied B: Rolling oil stock solution is electrostatically applied in the state of A C: Emulsion supply is stopped in the state of B D: Cool the steel plate by the steel plate cooling device in the state of C

The results are shown in Fig. 4. FIG. 4 is a graph showing the transition of the friction coefficient between the steel plate and the work roll during rolling in an experiment using a testing machine simulating the rolling oil supply facility 1 according to the present embodiment. In FIG. 4, the horizontal axis represents the time during rolling and the vertical axis represents the calculated friction coefficient, which shows the change over time in the friction coefficient during rolling.

Referring to FIG. 4, for a while after the start of rolling, only the emulsion is being supplied (that is, the state of A above), and the emulsion has a substantially constant friction coefficient. It can be confirmed that when the electrostatic coating of the rolling oil stock solution is started in this state (that is, when the state moves to the state B), the rolling oil stock solution is additionally supplied, and the friction coefficient is reduced.

It can be confirmed that when the supply of the emulsion is stopped in this state (that is, when the state shifts to the state C), the friction coefficient further decreases. It is considered that this is because the phenomenon in which the stock solution of rolling oil is washed away by the emulsion is avoided. From the results, in order to fully exert the effect of semi-direct lubrication, as in the rolling oil supply facility 1, the emulsion supply is stopped while electrostatic coating of the rolling oil stock solution is performed. You can see that is important.

It can be confirmed that, in this state, when the cooling of the steel sheet by the steel sheet cooling device is started (that is, when the state shifts to the above state D), the friction coefficient further decreases. It is considered that this is because when the steel sheet is cooled, the temperature of the rolling oil on the surface of the steel sheet also decreases and its viscosity increases.

From the results of the experiment described above, it can be confirmed that the friction coefficient, that is, the lubrication state can be changed by applying the rolling oil supply equipment 1 according to the present embodiment and appropriately switching the states A to D. It was In particular, the fact that the lubrication state changes in comparison with the other states in the state C and the state D is a finding newly obtained by the present inventors.

Here, for example, the rolling oil supply equipment described in Patent Document 1 separately includes an emulsion supply system and a rolling oil stock solution supply system by electrostatic coating. However, in the operation of the rolling oil supply facility described in Patent Document 1, the states of C and D are not mentioned. Therefore, in the conventional rolling oil supply equipment for semi-direct lubrication as described in Patent Document 1, the effect of changing the lubrication state by electrostatically applying the rolling oil stock solution, that is, the lubrication state in semi-direct lubrication I was not fully enjoying the effects of the changes. Therefore, it may be difficult to appropriately change the lubrication state to a desired range that does not cause a defect.

On the other hand, according to the rolling oil supply equipment 1 of the present embodiment, by appropriately switching the states A to D, as shown in FIG. 4, the rolling oil stock solution is electrostatically applied. It is possible to more appropriately obtain the effect of changing the lubrication state. That is, it becomes possible to change the lubrication state more efficiently by electrostatically applying the rolling oil stock solution. Therefore, it becomes possible to more appropriately change the lubrication state to a desired range that does not cause a defect.

The configuration of the rolling oil supply equipment 1 according to the present embodiment has been described above with reference to FIG. As described above, according to the present embodiment, it is possible to change the lubrication state during rolling more efficiently. Therefore, it is possible to avoid surface defects such as seizure and rolling instability phenomena such as chattering, and it is possible to improve yield and productivity in cold rolling.

Here, in the above description, the friction coefficient between the steel plate 10 and the work rolls 111 and 112 is calculated based on the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150. However, the present embodiment is not limited to such an example. The friction coefficient may be calculated by various known methods as long as the friction coefficient between the steel plate 10 and the work rolls 111 and 112 during rolling can be obtained.

Further, the specific device configuration of the rolling mill 1110 is not limited to the illustrated example. The rolling oil supply facility 1 according to the present embodiment is applicable to various general rolling mills for cold rolling. Therefore, the rolling mill 110 should just be comprised similarly to the rolling mill for general cold rolling, and the specific structure may be arbitrary. For example, the rolling mill 110 is not limited to a quadruple rolling mill, and may have another structure such as a six-fold rolling mill. The rolling mill 110 does not have to be a rolling mill that constitutes a cold tandem rolling line, and may be another rolling mill for cold rolling such as a rolling mill for reverse rolling.

Further, although the case where the rolled material rolled by the rolling mill 110 is the steel plate 10 has been described above, the present embodiment is not limited to this example. The rolling oil supply facility 1 according to the present embodiment may be applied to rolling of various metal materials.

Moreover, in the above description, the rolling oil supply equipment 1 was equipped with the steel plate cooling device 170 as a cooling mechanism for cooling the steel plate 10, but this embodiment is not limited to such an example. The cooling mechanism provided in the rolling oil supply facility 1 may be another device. If the rolling oil supply facility 1 includes a cooling mechanism that cools the steel sheet 10 and/or the work rolls 111 and 112, and the controller 180 appropriately controls the operation of the cooling mechanism, the steel sheet when the above-described emulsion supply is stopped. Since it is possible to obtain the cooling effect on the work rolls 10 and the work rolls 111 and 112, the specific device configuration of the cooling mechanism may be arbitrary. For example, the rolling oil supply facility 1 is installed as a cooling mechanism on the outlet side of the rolling mill 110 in addition to the steel plate cooling device 170 or in place of the steel plate cooling device 170, and the cooling water is supplied to the work rolls 111 and 112. A roll cooling device that cools the work rolls 111 and 112 by injecting

Further, in the present embodiment, the cooling of the steel plate 10 and the work rolls 111 and 112 in the cooling mechanism when the supply of the emulsion is stopped is not necessarily essential. For example, when rolling is performed under rolling conditions in which processing heat generation and friction heat generation are small, and when the temperature rise of the steel sheet 10 and the work rolls 111 and 112 can be sufficiently suppressed without supplying the emulsion, the control device 180 may not operate the cooling mechanism. In this case, the rolling supply facility 1 does not necessarily have to include the cooling mechanism.

(2. Rolling oil supply method)
With reference to FIG. 5, a processing procedure of the rolling oil supply method executed in the rolling oil supply facility 1 described above will be described. FIG. 5: is a flowchart which shows an example of the processing procedure of the rolling oil supply method which concerns on this embodiment. Each process shown in FIG. 5 corresponds to the process executed by the control device 180 shown in FIG. Since the details of each process have already been described with reference to FIG. 1, in the following description of the rolling oil supply method according to the present embodiment, a detailed description of each process will be omitted.

Referring to FIG. 5, in the rolling oil supply method according to the present embodiment, first, the supply of emulsion is started at the start of rolling (step S101).

Next, the coefficient of friction between the steel sheet 10 and the work rolls 111 and 112 is calculated using the measured value of the rolling load by the rolling load meter 140 and the measured value of the sheet speed by the sheet speed meter 150 (step S103). ..

Next, it is determined whether the calculated friction coefficient is less than or equal to a predetermined threshold value (step S105).

If the friction coefficient is less than or equal to the threshold value in step S105, no special processing is performed. In this case, the process returns to step S103 and stands by until the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 are obtained at the next measurement timing. Then, when these measured values are obtained, the processes of steps S103 and S105 are executed again.

On the other hand, if the friction coefficient is outside the target range in step S105, the process proceeds to step S107. In step S107, electrostatic coating of the rolling oil stock solution by the electrostatic coating device 130 is started.

When the electrostatic application of the rolling oil stock solution is started, the supply of the emulsion is stopped after a predetermined time has passed (step S109).

Then, thereafter, the cooling of the steel plate by the steel plate cooling device 170 is started (step S111). Note that the cooling of the steel plate by the steel plate cooling device 170 in step S111 may be started at substantially the same time as the supply of the emulsion is stopped in step S109, or the supply of the emulsion is stopped in step S109 and a predetermined time has elapsed. May be started after.

The processing procedure of the rolling oil supply method according to the present embodiment has been described above.

(3. Modified example)
Some modifications of the embodiment described above will be described. In the above embodiment, the friction coefficient is used as an index indicating the lubrication state, and the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 are controlled based on the friction coefficient. However, the present embodiment is not limited to this example. In the present embodiment, another physical quantity may be used as an index indicating the lubrication state, and the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 may be controlled based on the other physical quantity. Here, a modified example in which another physical quantity is used as an index indicating the lubrication state will be described. It should be noted that the rolling oil supply equipment according to each modification described below is different from the rolling oil supply equipment 1 shown in FIG. 1 described above in that the physical quantity serving as an index indicating the lubrication state is changed. It corresponds to the one in which the configuration of the measuring instrument and the like for obtaining is changed. Since the configuration other than such changes is the same as that of the rolling oil supply equipment 1, in the description of the rolling oil supply equipment according to each of the following modifications, matters overlapping with the rolling oil supply equipment 1 shown in FIG. 1 described above will be described. Omits the detailed description and mainly describes different matters.

(3-1. Modification using oil film thickness as an index indicating lubrication state)
With reference to FIG. 6, a configuration of a rolling oil supply facility according to a modification in which the oil film thickness immediately below the roll bite is used as an index indicating the lubrication state will be described. The oil film thickness directly below the roll bite can be an index showing the lubrication state, because if the oil film thickness is thick, lubrication is good, and if the oil film thickness is thin, lubrication is poor. FIG. 6 is a diagram showing a configuration example of a rolling oil supply facility according to a modification in which an oil film thickness immediately below a roll bite is used as an index indicating a lubrication state.

FIG. 6 shows a configuration example in which the rolling oil supply facility 2 according to the present modification is provided to the rolling mill 110 for cold rolling. Referring to FIG. 6, the rolling oil supply facility 2 according to the present modification includes an emulsion supply device 120 that supplies emulsion to the steel plate 10 and work rolls 111 and 112 of the rolling mill 110 on the inlet side of the rolling mill 110, and an emulsion supply. An electrostatic coating device 130, which is installed upstream of the device 120 in the rolling direction and electrostatically applies the rolling stock solution to the steel plate 10, a rolling load meter 140 that measures the rolling load in the rolling mill 110, and a rolling mill 110. A plate speed meter 150 that is installed on the entrance side and that measures the speed of the steel plate 10, and a grounding device 162 that is attached to the tension roll 161 that measures the tension applied to the steel plate 10 and that grounds the steel plate 10 via the tension roll 161. A steel plate cooling device 170 that is installed upstream of the electrostatic coating device 130 in the rolling direction and that cools the steel plate 10, and a control device that controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170. 210 is provided.

As described above, the rolling oil supply equipment 2 according to the present modification corresponds to the rolling oil supply equipment 1 shown in FIG. 1 described above in which the installation position of the plate speed meter 150 is changed to the entry side. Further, the function of the control device 210 is also changed.

The control device 210 controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 to dynamically control the lubrication state between the steel plate 10 and the work rolls 111 and 112 during rolling. change. In this modification, the oil film thickness immediately below the roll bite is used as an index indicating the lubrication state. The control device 210 controls the operation of each device based on the oil film thickness. The function of the control device 210 is the same as the function of the control device 180 shown in FIG. 1 except that the oil film thickness immediately below the roll bite is used as an index indicating the lubrication state.

Specifically, first, the control device 210 does not drive the electrostatic coating device 130 at the start of rolling, and causes the emulsion supply device 120 only to supply the emulsion.

In the rolling oil supply facility 2, the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 are sequentially transmitted to the control device 210 at a predetermined timing. The control device 210 uses the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 in a state where only the emulsion is being supplied, and uses the oil film thickness model to roll the roll. Calculate the oil film thickness just below the bite. Since the method of calculating the oil film thickness is well known, its detailed description is omitted here.

Then, the control device 210 determines whether the calculated oil film thickness is equal to or larger than a predetermined threshold value. Here, as in the case of the friction coefficient described with reference to FIG. 3, the threshold value is an oil film thickness that does not cause a defect due to insufficient lubrication such as seizure depending on the rolling conditions and the like. The lower limit of the desirable range is appropriately determined, for example, based on the results of experiments and simulations, past operation record data, and the like, and is stored in advance in a storage device (not shown in FIG. 6) provided in the rolling oil supply facility 2. Has been done. The control device 210 refers to the storage device to set a threshold value of the oil film thickness that matches the rolling condition of the rolling currently controlled, and uses the threshold value to perform the above determination process. It can be carried out.

If the calculated oil film thickness is equal to or greater than the threshold value as a result of this determination process, it indicates that the current lubrication state is in a good state in which no defect occurs. Therefore, in this case, the control device 210 does not perform special control.

On the other hand, when the calculated oil film thickness is below the threshold value, it indicates that the current lubrication state is a state in which lubrication may be insufficient and a defect may occur. Therefore, in this case, in order to improve the lubrication state, the control device 210 operates the electrostatic coating device 130 so that the oil film thickness is equal to or more than the threshold value, and the rolling stock solution is kept static. Start electrocoating. In this modification, for example, the correlation between the coating amount of the rolling oil stock solution applied to the steel sheet 10 by electrostatic coating and the oil film thickness immediately below the roll bite is acquired in advance by experiments, simulations, etc. It is stored in the storage device. The control device 210 refers to the storage device and uses the correlation between the amount of the stock solution of rolling oil applied to the steel sheet 10 and the oil film thickness, so that the oil film thickness can be increased by a desired amount. 130 can be operated appropriately.

Further, the control device 210 starts the electrostatic coating of the rolling oil stock solution by the electrostatic coating device 130, and then stops the emulsion supply by the emulsion supply device 120. As a result, it is possible to avoid the situation where the electrostatically applied rolling stock solution is washed away by the emulsion, and it is possible to more suitably obtain the lubricating effect by electrostatically applying the rolling stock solution. That is, it is possible to more efficiently increase the oil film thickness by electrostatically coating the rolling oil stock solution.

Then, the controller 210 operates the steel plate cooling device 170 to start cooling the steel plate 10. This makes it possible to appropriately cool the steel plate 10 and the work rolls 111 and 112 even when the supply of the emulsion is stopped. Note that the control device 210 may operate the steel plate cooling device 170 at substantially the same time as when the supply of the emulsion is stopped, or in a range in which the temperature increase of the steel plate 10 and the work rolls 111, 112 does not occur. It may be after an arbitrary time has passed since the supply of the emulsion was stopped.

After the start of rolling, the control device 210 controls the above-mentioned oil film thickness every time the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150 are transmitted while the emulsion is being supplied. And the process of determining whether the oil film thickness is greater than or equal to the threshold value are sequentially executed. Then, the control device 210 appropriately controls the above-described operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 according to the determination result.

Here, in order to confirm the effect of applying the rolling oil supply equipment 2, the present inventors conducted an experiment similar to the experiment for the rolling oil supply equipment 1 described with reference to FIG. I went to facility 2. Specifically, the present inventors created a tester that mimics the configuration in which the rolling oil supply facility 2 is provided for the rolling mill 110 described above, and performs rolling while rolling the steel sheet (coil). In order to simulate the rolling oil supply method in the oil supply equipment 2, the rolling oil supply equipment was operated in the order of A to D described above. Then, during this rolling, the oil film thickness immediately below the roll bite was sequentially calculated from the measured value of the rolling load and the measured value of the strip speed, and the transition of the oil film thickness during the rolling was investigated.

The results are shown in Fig. 7. FIG. 7 is a graph showing changes in the oil film thickness immediately below the roll bite during rolling in an experiment using a testing machine that imitates the rolling oil supply facility 2 according to the present modification. In FIG. 7, the horizontal axis represents the time during rolling and the vertical axis represents the calculated oil film thickness, and the time change of the oil film thickness during rolling is shown.

Referring to FIG. 7, for a while after the start of rolling, only the emulsion is being supplied (that is, the above-described state A), and the emulsion has a substantially constant oil film thickness. It can be confirmed that when electrostatic coating of the rolling oil stock solution is started in this state (that is, when the state moves to the above state B), the rolling oil stock solution is additionally supplied to increase the oil film thickness.

It can be confirmed that when the supply of the emulsion is stopped in this state (that is, when the state shifts to the state C), the oil film thickness further increases. It is considered that this is because the rolling oil stock solution is prevented from being washed away by the emulsion. As described above, from the result of the change in the oil film thickness, as in the result of the change in the friction coefficient shown in FIG. It can be confirmed that it is important to stop the supply of the emulsion during the period. As described above, even if the amount of the rolling oil stock solution applied to the steel plate 10 is constant, the value of the oil film thickness changes depending on whether or not the emulsion is supplied. When operating the electrostatic coating apparatus 130 so that the oil film thickness can be increased by a desired amount based on the obtained correlation, a change in the oil film thickness caused by stopping the supply of the emulsion is taken into consideration. It is necessary to determine the coating amount of the rolling oil stock solution by the electrocoating device 130.

It can be confirmed that when the cooling of the steel sheet by the steel sheet cooling device is started in this state (that is, when the state shifts to the above state D), the oil film thickness is further increased, albeit slightly. It is considered that this is because when the steel sheet is cooled, the temperature of the electrostatically applied rolling oil is also lowered and its viscosity is increased. As described above, even if the amount of the undiluted solution of rolling oil applied to the steel plate 10 is constant, the value of the oil film thickness changes according to the temperature of the steel plate 10. When the electrostatic coating device 130 is operated so that the oil film thickness can be increased by a desired amount based on the above correlation, the electrostatic film thickness is further considered in consideration of the change in the oil film thickness due to the temperature change of the steel plate 10. It is necessary to determine the coating amount of the rolling oil stock solution by the coating device 130.

From the results of the experiment described above, the effect of changing the lubrication state by electrostatically applying the rolling oil stock solution by applying the rolling oil supply facility 2 according to the present modification and appropriately switching the states A to D above It was also confirmed from the transition of the oil film thickness that it was possible to obtain more suitably.

The configuration of the rolling oil supply equipment 2 according to the modified example in which the oil film thickness immediately below the roll bite is used as an index indicating the lubrication state has been described above with reference to FIG.

Here, in the above description, the oil film thickness immediately below the roll bite is calculated based on the measured value of the rolling load by the rolling load meter 140 and the measured value of the plate speed by the plate speed meter 150. The oil film thickness may be obtained by various known methods, and the oil film thickness may be calculated by another method as long as the oil film thickness immediately below the roll bite during rolling can be obtained.

(3-2. Modified example in which plate temperature is used as an index indicating the lubrication state)
With reference to FIG. 8, a configuration of a rolling oil supply facility according to a modified example using the plate temperature on the outlet side of the rolling mill 110 as an index indicating the lubrication state will be described. The plate temperature on the delivery side of the rolling mill 110 indirectly indicates the plate temperature immediately below the roll bite, and if the plate temperature is high, the plate temperature immediately below the roll bite will be high, and the viscosity of the rolling oil will be reduced, thus causing lubrication. When the plate temperature is low, the plate temperature immediately below the roll bite is also low, and the viscosity of the rolling oil increases, so that the lubrication becomes good. Therefore, the plate temperature on the delivery side of the rolling mill 110 can also be an index indicating the lubrication state. FIG. 8: is a figure which shows an example of a structure of the rolling oil supply equipment which concerns on the modification which uses the plate temperature on the outgoing side of the rolling mill 110 as an index which shows a lubrication state.

FIG. 8 shows a configuration example in the case where the rolling oil supply facility 3 according to the present modification is provided to the rolling mill 110 for cold rolling. Referring to FIG. 8, the rolling oil supply facility 3 according to the present modification includes an emulsion supply device 120 that supplies emulsion to the steel plate 10 and the work rolls 111 and 112 of the rolling mill 110 on the inlet side of the rolling mill 110, and an emulsion supply. An electrostatic coating device 130 that is installed upstream of the device 120 in the rolling direction and electrostatically applies the rolling stock solution to the steel plate 10, and a plate temperature that is installed on the outlet side of the rolling mill 110 and measures the temperature of the steel plate 10. A total of 320, a grounding device 162 attached to a tension roll 161 for measuring the tension applied to the steel plate 10 and grounding the steel plate 10 via the tension roll 161, and installed on the upstream side in the rolling direction of the electrostatic coating device 130. A steel plate cooling device 170 that cools the steel plate 10 and a control device 210 that controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 are provided.

As described above, the rolling oil supply equipment 3 according to the present modification is the same as the rolling oil supply equipment 1 shown in FIG. 1 except that the plate thermometer 320 is provided in place of the rolling load meter 140 and the plate speed meter 150. Corresponding to. Further, the function of the control device 310 is also changed.

The control device 310 controls the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 to dynamically control the lubrication state between the steel plate 10 and the work rolls 111 and 112 during rolling. change. In this modification, the plate temperature on the delivery side of the rolling mill 110 is used as an index indicating the lubrication state. The control device 310 controls the operation of each device based on the plate temperature. The function of the control device 310 is the same as the function of the control device 180 shown in FIG. 1 except that the plate temperature on the delivery side of the rolling mill 110 is used as an index indicating the lubrication state.

Specifically, first, the control device 310 does not drive the electrostatic coating device 130 at the start of rolling, but only causes the emulsion nozzle 121 to supply the emulsion.

In the rolling oil supply facility 3, the measured value of the plate temperature by the plate thermometer 320 is sequentially transmitted to the control device 310 at a predetermined timing. The control device 310 determines whether or not the measured value of the plate temperature by the plate thermometer 320 is equal to or lower than a predetermined threshold value while only the emulsion is being supplied. Here, as in the case of the friction coefficient described with reference to FIG. 3, the threshold value corresponds to a plate temperature that does not cause a defect such as seizure due to insufficient lubrication depending on the rolling conditions and the like. The upper limit of the desirable range is appropriately determined based on, for example, the results of experiments and simulations, past operation record data, and the like, and is stored in advance in a storage device (not shown in FIG. 8) provided in the rolling oil supply facility 3. Has been done. By referring to the storage device, the control device 310 sets a plate temperature threshold value that matches the rolling conditions of the rolling currently controlled, and uses the threshold value to perform the above determination process. It can be carried out.

As a result of this determination processing, when the measured plate temperature is equal to or lower than the threshold value, it indicates that the current lubrication state is in a good state in which no defect occurs. Therefore, in this case, the control device 310 does not perform special control.

On the other hand, when the measured plate temperature exceeds the threshold value, it indicates that the current lubrication state is a state in which lubrication is insufficient, which may cause a defect. Therefore, in this case, in order to improve the lubrication state, the control device 310 operates the electrostatic coating device 130 so that the plate temperature is equal to or lower than the threshold value, and the rolling oil stock solution is kept static. Start electrocoating. In this modification, for example, a correlation between the amount of rolling oil stock solution applied to the steel plate 10 by electrostatic coating and the plate temperature on the delivery side of the rolling mill 110 is acquired in advance by, for example, an experiment or a simulation, and a table or the like is obtained. Is stored in the storage device in the form of. The controller 310 refers to the storage device and uses the correlation between the coating amount of the rolling oil stock solution on the steel plate 10 and the plate temperature so that the plate temperature can be lowered by a desired amount. 130 can be operated appropriately.

Further, the control device 310 starts the electrostatic coating of the rolling oil stock solution by the electrostatic coating device 130, and then stops the emulsion supply by the emulsion supply device 120. As a result, it is possible to avoid the situation where the electrostatically applied rolling stock solution is washed away by the emulsion, and it is possible to more suitably obtain the lubricating effect by electrostatically applying the rolling stock solution. That is, it becomes possible to more efficiently lower the plate temperature by electrostatically applying the rolling oil stock solution.

Then, thereafter, control device 310 operates steel plate cooling device 170 to cool steel plate 10. This makes it possible to appropriately cool the steel plate 10 and the work rolls 111 and 112 even when the supply of the emulsion is stopped. Note that the control device 310 may operate the steel plate cooling device 170 at substantially the same time as when the supply of the emulsion is stopped, or in a range in which the temperature rise of the steel plate 10 and the work rolls 111 and 112 does not occur. It may be after an arbitrary time has passed since the supply of the emulsion was stopped.

After the start of rolling, control device 310 determines whether or not the plate temperature is equal to or less than a threshold value every time the plate temperature measured by plate thermometer 320 is transmitted while the emulsion is being supplied. Are sequentially executed. Then, the control device 310 appropriately executes the above-described control of the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170 according to the determination result.

Here, in order to confirm the effect of applying the rolling oil supply equipment 3, the present inventors performed an experiment similar to the experiment for the rolling oil supply equipment 1 described with reference to FIG. The equipment 3 was also visited. Specifically, the present inventors created a tester that mimics the configuration in which the rolling oil supply equipment 3 is provided for the rolling mill 110 described above, and performs rolling while rolling the steel sheet (coil). In order to simulate the rolling oil supply method in the oil supply equipment 3, the rolling oil supply equipment was operated in the order of A to D described above. Then, during this rolling, the plate temperature on the delivery side of the rolling mill was sequentially measured, and the transition of the plate temperature during rolling was investigated.

The results are shown in Fig. 9. FIG. 9 is a graph showing changes in plate temperature on the rolling mill outlet side during rolling in an experiment using a tester that imitates the rolling oil supply facility 3 according to the present modification. In FIG. 9, the horizontal axis represents the time during rolling and the vertical axis represents the measured plate temperature, and the time change of the plate temperature during rolling is shown.

Referring to FIG. 9, for a while after the start of rolling, only the emulsion is being supplied (that is, the above-described state A), and the emulsion provides a substantially constant plate temperature. It can be confirmed that when the electrostatic coating of the rolling oil stock solution is started in this state (that is, when the state moves to the state B), the rolling oil stock solution is additionally supplied, and the plate temperature is lowered.

In this state, it can be confirmed that the plate temperature increases when the supply of the emulsion is stopped (that is, when the state shifts to the state C). It is considered that this is because the effect of cooling the steel sheet by the emulsion cannot be obtained. However, at this time, since it is possible to avoid the situation where the electrostatically applied rolling stock solution is washed away by the emulsion, it is considered that the lubrication is better than the state B above.

In this state, when the cooling of the steel sheet by the steel sheet cooling device is started (that is, when the state shifts to the above state D), it can be confirmed that the plate temperature decreases due to the cooling effect of the steel sheet cooling device. Since there is a concern that seizure may occur when the plate temperature rises, from this result, when the emulsion supply is stopped as in the rolling oil supply facility 3 according to the present modification, the addition by the cooling mechanism is performed. It was confirmed that it is more preferable to cool the typical steel plate and/or work roll.

Here, as shown in the above results, even if the amount of the undiluted solution of rolling oil applied to the steel plate 10 is constant, the presence or absence of the emulsion is supplied (that is, the presence or absence of the cooling effect of the emulsion) and the steel plate cooling device. The value of the plate temperature on the exit side of the rolling mill 110 changes depending on whether or not the operation of 170 is performed. Therefore, as in the case of the coefficient of friction, when operating the electrostatic coating device 130 so that the plate temperature can be reduced by a desired amount based on the above-obtained correlation, the supply of emulsion should be stopped. Also, it is preferable to determine the coating amount of the stock solution of rolling oil by the electrostatic coating device 130 in consideration of the change in plate temperature due to the operation of the steel plate cooling device 170.

The configuration of the rolling oil supply equipment 3 according to the modified example in which the plate temperature on the delivery side of the rolling mill 110 is used as an index indicating the lubrication state has been described above with reference to FIG. 8. Here, in the above description, the measured value of the plate temperature by the plate thermometer 320 is used as the temperature of the steel plate 10, but in the present modification, the temperature of the steel plate 10 may be obtained by another method, The position at which the temperature of the steel sheet 10 is obtained is not limited to the delivery side of the rolling mill 110. For example, a method is known in which the rolling temperature and the rolling speed are used to determine the rolling temperature immediately below the roll bite by a rolling temperature model. Therefore, using such a method, the plate temperature immediately below the roll bite may be used as an index indicating the lubrication state. Specifically, in the rolling oil supply facility 3, a rolling load meter and a plate speed meter are provided in place of the plate thermometer 320, and the measured values of the rolling load and the plate speed by the rolling load meter and the plate speed meter are used, The controller 310 may obtain the plate temperature immediately below the roll bite by using the plate temperature model. In addition, various known methods may be used as long as the temperature of the steel sheet 10 during rolling can be obtained.

In order to confirm the effect of the present invention, a rolling oil supply equipment having the same configuration as the rolling oil supply equipment 1 according to the present embodiment described with reference to FIG. It was applied to the final stand of the inter-tandem rolling mill and rolled. The conditions of rolling oil and rolling conditions are as follows.

A synthetic ester oil was used as the base oil of the emulsion to be supplied. The emulsion was prepared at a concentration of 1.5 (%), and the supply amount during rolling was 20 (L/min) on one side.

The electrostatic coating device was installed at a position 2.5 m upstream from the final stand. As the rolling oil stock solution to be electrostatically applied, the same synthetic ester oil as the base oil of the emulsion was used.

Further, the steel plate cooling device was installed at a position separated by 1.5 m upstream from the electrostatic coating device.

A steel plate was used as the rolled material. The steel plate is ordinary steel, and its shape is a plate thickness of 1.00 (mm) and a plate width of 1000 (mm).

The rolling was accelerated to 2200 (mpm), and after performing steady rolling for 10 minutes in that state, the rolling was decelerated to finish.

Under the above conditions, 20 coils were rolled, and the state of the rolled coil was investigated. In addition, in order to compare with the result when the rolling oil supply equipment 1 according to the present embodiment is not applied, in this example, the emulsion supply device, the electrostatic coating device, and the steel plate cooling device were operated as follows.

That is, first, start the rolling while supplying only the emulsion, during that, based on the rolling load measured by the rolling load meter, and the plate speed of the coil measured by the plate speed meter provided on the rolling mill exit side, the coil and The coefficient of friction with the work roll was calculated. Then, after a lapse of 1 minute with the calculated friction coefficient exceeding a predetermined threshold value, electrostatic coating of the rolling oil stock solution by the electrostatic coating apparatus was started. Then, after 1 minute has elapsed from the start of electrostatic coating of the rolling oil stock solution by the electrostatic coating apparatus, the supply of emulsion was stopped. Further, 1 minute after the supply of the emulsion was stopped, cooling of the steel plate by the steel plate cooling device was started.

As a result, in the section (section a) from when the calculated friction coefficient exceeds the predetermined threshold to when the electrostatic application of the rolling oil stock solution is started, a large number of heats due to seizure on the surface of the coil are generated. Scratch was confirmed. On the other hand, in the section from the start of electrostatic coating of the rolling oil stock solution to the stop of the emulsion supply (section b), the frequency of heat scratches per unit area of the coil surface is lower than in section a. I was able to confirm that it is doing. It is considered that this is because the oil film thickness on the coil surface increased and the friction coefficient decreased due to electrostatic coating of the rolling oil stock solution.

Further, in the section (section (c)) from the stop of the supply of the emulsion to the start of cooling the coil by the steel plate cooling device, the frequency of heat scratches per unit area of the coil surface is further reduced. I was able to confirm that. This is because by stopping the supply of the emulsion, the effect of washing off the oil film on the coil surface formed by electrostatic coating of the rolling oil stock solution is reduced, and the coil is kept in a state where the oil film thickness on the coil surface is sufficiently maintained. It is considered that this is because the friction coefficient further decreased because the roll bite was reached.

Then, in the section (section (d)) after the start of cooling of the coil by the steel plate cooling device, generation of heat scratch was not confirmed in all the coils. This indicates that the rise of the plate temperature due to the suspension of the supply of the emulsion was suppressed by the steel plate cooling device, so that the occurrence of heat scratch was suppressed.

In order to further confirm the effect of the present invention, the rolling oil supply equipment having the same configuration as the rolling oil supply equipment 2 according to the modified example of the present embodiment described with reference to FIG. 6 is actually operated. It was applied to the final stand of the cold tandem rolling mill that is being performed and rolled. The conditions of the rolling oil and the rolling conditions are the same as those in the above-described embodiment of the rolling oil supply facility 1.

In the present embodiment, as described with reference to FIG. 6, the oil film thickness immediately below the roll bite is sequentially calculated during the rolling while supplying only the emulsion, and the oil film thickness is a predetermined threshold value. When the value was below the value, the electrostatic coating of the rolling oil stock solution by the electrostatic coating device was started, and then the emulsion supply was stopped. That is, the emulsion supply device and the electrostatic coating device were appropriately operated so that the oil film thickness immediately below the roll bite was equal to or greater than a predetermined threshold value.

Under the above conditions, 20 coils were rolled, and the state of the rolled coil was investigated. As a result, generation of heat scratch was not confirmed in all of the 20 coils. By applying the rolling oil supply equipment 2 and operating the emulsion supply device and the electrostatic coating device appropriately, the oil film thickness immediately below the roll bite can be controlled to an appropriate thickness, and the occurrence of heat scratches. It shows that it could be effectively suppressed.

In order to further confirm the effect of the present invention, a rolling oil supply facility having the same configuration as the rolling oil supply facility 3 according to another modification of the present embodiment described with reference to FIG. 8 is actually operated. Was applied to the final stand of the cold tandem rolling mill in which The conditions of the rolling oil and the rolling conditions are the same as those in the above-described embodiment of the rolling oil supply facility 1.

In this example, as described with reference to FIG. 8 above, the plate temperature on the delivery side of the final stand was sequentially measured during the rolling while supplying only the emulsion, and the plate temperature was set to a predetermined value. When the threshold value was exceeded, electrostatic coating of the stock solution of rolling oil by the electrostatic coating device was started, then the supply of emulsion was stopped, and further cooling of the steel plate by the steel plate cooling device was started. That is, the emulsion supply device, the electrostatic coating device, and the steel plate cooling device were appropriately operated so that the plate temperature on the delivery side of the final stand was equal to or lower than the predetermined threshold value.

Under the above conditions, 20 coils were rolled, and the state of the rolled coil was investigated. As a result, generation of heat scratch was not confirmed in all of the 20 coils. This is because the friction coefficient decreased due to the increase in the oil film thickness on the coil surface due to the application of the undiluted rolling oil by the electrostatic coating device, and the plate temperature was controlled within the appropriate range by the coil cooling by the steel plate cooling device. This indicates that the occurrence of heat scratch was effectively suppressed.

From the results in each of the above examples, by applying the present invention, it is possible to efficiently adjust the lubricating state between the coil and the work roll in cold rolling, it is possible to prevent the occurrence of seizure. I confirmed that I can do it. Therefore, by applying the present invention, it is possible to avoid surface defects such as seizure and rolling instability phenomena such as chattering, and it is possible to improve yield and productivity in cold rolling. ..

(4. Supplement)
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

Here, the specific device configuration of the control devices 180, 210, 310 described above is not limited. The control devices 180, 210, 310 may have a function of executing the arithmetic processing described above and a function of controlling the operations of the emulsion supply device 120, the electrostatic coating device 130, and the steel plate cooling device 170, and the device configuration thereof. May be arbitrary. For example, the control devices 180, 210, 310 may be a processor such as a CPU (Central Processing Unit), or a control board on which a processor and a storage element such as a memory are mounted together. Alternatively, the control devices 180, 210, 310 may be general-purpose information processing devices such as PCs (Personal Computers). The respective functions described above can be realized by the processors of the control devices 180, 210, 310 operating according to a predetermined program. As the storage device described above, various known devices capable of storing information, such as a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device or a magneto-optical storage device, may be used. You can

Further, it is possible to create a computer program for realizing each function of the control devices 180, 210, 310 and install the computer program in a processing device such as a PC. It is also possible to provide a computer-readable recording medium in which such a computer program is stored. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the computer program may be distributed via a network, for example, without using a recording medium.

1, 2, 3 Rolling oil supply equipment 10 Steel plate 110 Rolling mill 111, 112 Work roll 113, 114 Backup roll 120 Emulsion supply device 121 Emulsion nozzle 122 Emulsion tank 123 Valve 130 Electrostatic coating device 131 Electrostatic coating nozzle 132 Rolling oil stock solution Storage tank 133 Valve 140 Rolling load meter 150 Plate speed meter 161 Tension reel 162 Earthing device 170 Steel plate cooling device 180, 210, 310 Control device 320 Plate thermometer

Claims (8)

An emulsion supply device that supplies an emulsion to the work roll of the rolling material and the rolling mill on the entrance side of the rolling mill,
On the upstream side in the rolling direction than the emulsion supply device, an electrostatic coating device for electrostatically coating a rolling stock solution on the rolled material,
A control device for controlling the operation of the emulsion supply device and the electrostatic coating device,
Equipped with
The control device, when the rolled material is electrostatically applied rolling oil stock solution by the electrostatic coating device is being rolled, to stop the supply of emulsion by the emulsion supply device,
Rolling oil supply equipment. By a control from the control device, further comprising a cooling mechanism for cooling at least one of the rolled material and the work roll,
The control device electrostatically applies a rolling oil stock solution to the rolled material by the electrostatic coating device, and when the emulsion supply by the emulsion supply device is stopped, the rolled material by the cooling mechanism and Cooling at least one of the work rolls,
The rolling oil supply equipment according to claim 1. The cooling mechanism is a rolled material cooling device that injects cooling water to the rolled material on the upstream side in the rolling direction with respect to the electrostatic coating device,
The rolling oil supply equipment according to claim 2. The cooling mechanism is a roll cooling device that injects cooling water to the work rolls on the exit side of the rolling mill,
The rolling oil supply equipment according to claim 2. The control device calculates the friction coefficient between the rolled material and the work roll while supplying the emulsion by the emulsion supply device, and the calculated friction coefficient exceeds a predetermined threshold value. In this case, electrostatic coating of the rolling oil stock solution by the electrostatic coating device is started, and the supply of emulsion by the emulsion supply device is stopped.
The rolling oil supply equipment according to any one of claims 1 to 4. The control device calculates the oil film thickness immediately below the roll bite while supplying the emulsion by the emulsion supply device, and when the calculated oil film thickness is below a predetermined threshold value, the electrostatic coating is performed. Starting the electrostatic application of the rolling oil stock solution by the device, stop the emulsion supply by the emulsion supply device,
The rolling oil supply equipment according to any one of claims 1 to 4. The control device, while supplying the emulsion by the emulsion supply device, the temperature of the rolled material measured on the exit side of the rolling mill, or the rolled material immediately below the roll bite calculated by the control device When the temperature of exceeds a predetermined threshold value, to start the electrostatic coating of the rolling oil stock solution by the electrostatic coating device, to stop the emulsion supply by the emulsion supply device,
The rolling oil supply equipment according to any one of claims 1 to 4. Using the rolling oil supply equipment according to any one of claims 1 to 7, at least the operations of the emulsion supply device and the electrostatic coating device are dynamically controlled during rolling.
Rolling oil supply method.

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