JP4505231B2 - Lubricating oil supply method in cold rolling - Google Patents

Description

  The present invention relates to a lubricating oil supply method in cold rolling, and more particularly to a neat lubrication method for supplying a lubricating oil stock solution to a work roll.

  In cold rolling, emulsion lubrication is usually used except for stainless steel plates. However, many lubricant oils are wasted by emulsion lubrication, and when the rolling speed is increased, insufficient lubrication may occur and seizure may occur.

  As a technique for solving the problem of emulsion lubrication, there is neat lubrication in which a lubricating oil stock solution (hereinafter simply referred to as lubricating oil) is supplied to a roll and / or a steel plate. Although neat lubrication is an effective means for reducing friction, the conventional lubricating oil supply method has the following problems because the lubricating oil stock solution is supplied from the nozzle.

  (1) Excessive lubrication may cause slipping and wrinkles. (2) If the lubricating oil supply amount is reduced too much, the lubricating oil has a higher viscosity than the emulsion, so it does not spread over the entire roll or plate, and may cause seizure flaws in the parts where it is not supplied (non-uniform in the width direction). . (3) Lubricating oil spilling from the plate end and roll end is increased from the current level, and the yield is deteriorated particularly in direct lubrication. (4) In recirculation lubrication, although yield does not deteriorate as much as direct lubrication, it is difficult to remove impurities for reuse because of its high viscosity and easy inclusion of impurities.

As a technique for solving the above-mentioned neat lubrication problem, a lubricating oil supply device for a work roll for rolling steel sheets, which is provided with a discharge port for supplying lubricating oil close to the work roll with a gap of 5 mm or less. There is a device. In this apparatus, lubricating oil is oozed out from the pores of the network structure of the discharge port and supplied to the work roll. The amount of lubricating oil supplied is controlled by adjusting the pressure applied to the lubricating oil. (For example, refer to Patent Document 1).
JP 2001-179313 A (4th page, 5th page, FIG. 1 and FIG. 4)

  The conventional method for neat lubrication of rolling rolls is effective in reducing the friction coefficient. However, since the lubricating oil oozes out from the pores and the pressure applied to the lubricating oil is adjusted to control the supply amount of the lubricating oil, the control response may be delayed. For this reason, there was a possibility that seizure flaws would occur.

  The present invention provides a lubricating oil supply method in cold rolling that can produce a high-quality product that is excellent in responsiveness of the lubricating oil supply control and has no seizure flaws.

The lubricating oil supply method in cold rolling according to the present invention is a lubricating oil supply method in cold rolling in which a lubricating oil stock solution is supplied to the roll bite inlet side, and the roll peripheral speed of the rolling mill and the plate speed on the outlet side of the rolling mill are By measuring and calculating the advance rate , by adjusting the air flow rate to the roll bite entry side by injecting the lubricant oil stock in a mist with compressed gas from the lubricant nozzle so that the advance rate falls within the set range supplied while controlling the lubricating oil supply amount, the supplied cooling water to at least the work rolls at the delivery side of the rolling mill, cooling water adhering to the roll surface and / or the metal plate surface on the delivery side of the rolling mill work roll exit side Is removed with a drainer. Here, the lubricating oil stock solution is made of mineral oil, fat or synthetic lubricating oil, and includes those to which additives such as antioxidants and oiliness improvers are added.

The lubricating oil supply method in cold rolling according to the present invention is a lubricating oil supply method in cold rolling in which a lubricating oil stock solution is supplied to the roll bite inlet side, and the oil film thickness is measured with an oil film thickness meter. While controlling the lubricating oil supply amount by adjusting the air flow rate to the roll bite inlet side by injecting the lubricating oil stock solution in a mist with compressed gas from the lubricating oil nozzle so that the measured oil film thickness matches the target value Then, cooling water is supplied to at least the work roll on the outlet side of the rolling mill, and the cooling water adhering to the roll surface on the outlet side of the work roll and / or the metal plate surface on the outlet side of the rolling mill is removed by a draining device.

  When lubricating oil supply control is performed based on the measured value of the oil film thickness, an oil film thickness meter is installed on the upper and lower surfaces of the metal plate at the rolling mill outlet side, and the rolling mill inlet side is set so that the measured oil film thickness matches the target value. The lubricating oil supply amount may be controlled separately up and down, and a plurality of lubricating oil nozzles are installed along the plate width direction, and a plurality of oil film thickness meters are arranged along the plate width direction on the rolling mill exit side. The lubricating oil supply amount on the rolling mill entry side may be controlled so that the measured oil film thickness at each location matches the target value.

  In this invention, the lubricating oil stock solution is sprayed from the lubricating oil nozzle in the form of a mist with compressed gas and supplied to the roll bite inlet side. Since the lubricating oil supply amount can be controlled by the flow rate of the compressed gas, high responsiveness and accuracy of the lubricating oil supply control can be obtained. As a result, it is possible to prevent the occurrence of seizure flaws due to insufficient lubrication and to manufacture a high-quality product, and to further reduce the lubricating oil.

  Moreover, the cooling water adhering to the roll surface on the work roll exit side and / or the metal plate surface on the exit side of the rolling mill is removed by a draining device. When removing the cooling water adhering to the roll surface on the work roll exit side, the lubricating oil can be sufficiently adhered to the surface of the metal plate. When removing the cooling water adhering to the metal plate surface on the rolling mill exit side, an oil film thickness meter can be installed to measure the oil film thickness. By performing feedback control of the oil film thickness based on the measured value of the oil film thickness, the required oil film thickness can be obtained with higher accuracy. Furthermore, by using a draining plate as the draining device, it is possible to prevent scattering of mist and cooling water and maintain a good work and equipment environment.

  In the first embodiment of the present invention, lubricating oil is supplied on the roll bite entry side in a sprayed state using compressed air without mixing liquid lubricating oil (lubricating oil stock solution) with water at room temperature, Supply cooling water to the roll exit side. And the cooling water adhering to the exit side surface of a work roll is removed with a draining board with the draining board arrange | positioned at the work roll exit side.

  FIG. 1 shows an example of a cold rolling mill that implements the lubricating oil supply method. Hereinafter, description will be made assuming that the metal plate is a steel plate. The rolling mill 10 is a four-high rolling mill provided with a work roll 12 and a backup roll 14. In the rolling mill 10, the lubricating oil is sent from the lubricating oil tank 30 to the lubricating oil header 20 via the piping 32 by the lubricating oil pump 34. Lubricating oil flows from the lubricating oil header 20 into a plurality of lubricating oil nozzles 22 arranged along the roll axis direction. On the other hand, the dried compressed air from the compressed air tank 40 is supplied to the lubricating oil nozzle 22 through the pipe 42. The lubricating oil is mixed with the compressed air and ejected from the lubricating oil nozzle 22 to be sprayed and supplied to the work roll 12 and the steel plate 1. Since it is neat lubrication, the friction coefficient can be effectively reduced. The lubricant pressure is kept constant by the lubricant pressure control valve 36, and the air flow rate is adjusted by the air flow rate control valve 46 to control the lubricant supply amount.

In emulsion lubrication, a sufficient cooling effect can be obtained due to the high thermal conductivity of water, but a sufficient cooling effect cannot be expected with the air atomization method. In order to prevent seizure, cooling water is sprayed on the work roll 12 from the rolling mill exit side. Therefore, in this embodiment, a plurality of cooling water nozzles 26 are arranged along the roll axis direction on the work roll exit side of the rolling mill 10 to cool the work roll 12 with water. The cooling water is sent from the cooling water tank 50 through the piping 52 to the cooling water header 24 by the cooling water pump 54. The cooling water is sprayed on the exit surface of the work roll 12 from a plurality of cooling water nozzles 26 attached to the cooling water header 24 along the roll axis direction, thereby cooling the work roll 12. The amount of cooling water is adjusted by a cooling water flow rate adjustment valve 56.

  When the scattered cooling water adheres to the surface of the work roll 12, adhesion of the lubricating oil to the steel plate 1 is hindered, so the draining plate 28 is provided close to the work roll exit side. The draining plate 28 is located on the downstream side of the cooling water nozzle 26 in the roll rotation direction. The gap between the work roll surface and the tip surface of the draining plate 28 is about 0 to 5 mm. Therefore, the draining plate 28 prevents the scattered cooling water from adhering to the work roll 12 and ensures that the lubricating oil adheres to the steel plate 1. Further, the draining plate 28 prevents cooling water and fume from being scattered around the rolling mill and maintains a good work and equipment environment. When the draining plate 28 is made of a soft material such as plastic, the work roll surface and the tip of the draining plate 28 may be in contact with each other (gap is 0 mm).

  Control of the amount of lubricating oil supplied is based on an advanced rate that is closely related to the coefficient of friction. The work roll peripheral speed is measured by a work roll rotational speed meter (not shown), and the plate speed is measured by a plate speed meter 62 on the delivery side of the rolling mill. These measurement results are sent to the lubricating oil supply control device 60, and the advance rate is calculated. The lubricating oil supply control device 60 obtains a required lubricating oil supply amount based on the relationship between the friction coefficient and the advanced rate, and outputs an operation signal to the air flow rate adjustment valve 46. As a result, the amount of lubricating oil supplied is controlled, and the oil film is maintained at a required thickness.

  In the second embodiment of the present invention, lubricating oil is supplied in a sprayed state on the roll bite entry side using compressed air without mixing liquid lubricant at room temperature with water and cooled to the work roll exit side. Supply water. And the cooling water adhering to the steel plate surface is removed with a draining board with the draining board arrange | positioned at the rolling mill delivery side.

  FIG. 2 shows an example of a rolling mill that implements the lubricating oil supply method. In FIG. 2, devices and members similar to those shown in FIG. 1 are assigned the same reference numerals, and detailed descriptions thereof are omitted.

  A draining plate 29 is disposed on the exit side of the rolling mill 10. Oil film thickness gauges 64 and 66 for measuring the oil film thickness on the front and back surfaces of the steel plate 1 are provided on the downstream side of the draining plate 29. The gap between the steel plate surface and the tip surface of the draining plate 29 is about 0 to 5 mm.

  The cooling water adhering to the surface of the cooling water is removed by the draining plate 29, and there is almost no environmental problem because the fume is not scattered in a large amount around the rolling mill. Is possible. As the oil film thickness meters 64 and 66, for example, an infrared type oil film thickness meter can be used.

  In the air atomization method, at least slip generation or supply unevenness due to excessive lubrication does not occur. The supplied lubricating oil forms an oil reservoir at the roll bite inlet, and thereafter, it is considered that all of the supplied amount is introduced into the roll bite, and therefore the oil film thickness meter on the outlet side is not essential. However, since various disturbances occur in normal operation, it is desirable to perform feedback control using an oil film thickness meter in order to supply the minimum amount of lubricating oil.

  In the feedback control, the target oil film thickness is set to the minimum oil film thickness that does not cause seizure under the rolling conditions from the past operation results. The oil film thickness measured by the oil film thickness meters 64 and 66 on the delivery side of the rolling mill is input to the lubricating oil supply control device 60. The lubricating oil supply control device 60 outputs an operation signal to the compressed air flow rate adjustment valve 46 based on the difference between the target oil film thickness and the actually measured oil film thickness. By adjusting the compressed air flow rate, the amount of lubricating oil supplied changes, and the target oil film thickness is obtained.

  If a plurality of oil film thickness meters 64 and 66 are installed in the plate width direction, it is possible to eliminate uneven oil film thickness in the plate width direction. By measuring the oil film thickness distribution in the plate width direction and supplying the lubricating oil in consideration of the overlap from the adjacent lubrication supply ends, the oil film thickness can be made uniform in the plate width direction. In this case, a compressed air flow rate adjusting valve 46 is provided for each pipe 42 connecting the compressed air tank 40 and the lubricating oil nozzle 22 to adjust the compressed air flow rate for each lubricating oil nozzle. Conversely, it is also possible to intentionally create medium elongation and end elongation by changing the amount of lubricating oil supplied in the plate width direction. In particular, when high-tensile rolling is performed, rolling may be performed in an end-elongated manner in order to avoid plate breakage due to minute cracks at the plate end, but this embodiment is also effective for this purpose.

  The present invention is not limited to the above embodiment. For example, a spraying device that sprays non-combustible compressed gas such as compressed air onto the work roll surface and / or the metal plate surface in addition to the draining plate may be used as the draining device. In the second embodiment, a draining plate may be provided on the exit side of the work roll. In this case, an oil film having a required thickness can be more reliably formed on the surface of the metal plate. The oil film thickness meter may be disposed on either the upper or lower surface of the metal plate. The compressed gas supplied to the lubricating oil nozzle may be non-combustible gas such as nitrogen gas in addition to air. Lubricating oil nozzles may be arranged at a distance from the roll tool to the upstream side of the rolling mill. In addition to steel, the rolled material may be a metal such as titanium, aluminum, magnesium, copper, or an alloy of these metals.

  Coil rolling was performed using a single stand 4Hi experimental mill. Rolling was carried out by installing one oil film thickness meter on each of the upper and lower surfaces of the steel sheet by the air atomization method. Cold water was supplied to the work roll. The minimum required oil film thickness was obtained by conducting an experiment in which the supply rate was decreased after a rolling speed of 1200 m / min in advance by the air atomization method. In the experiment, when the speed was increased to 1200 m / min, steady rolling was started, rolling was performed for 20 minutes under the above conditions, and then the experiment was terminated with the speed reduced. Although the coil was confirmed after rolling, the occurrence of seizure flaws was not observed.

  Next, it was rolled with 3% concentration emulsion lubrication. The concentration was determined by converting the minimum oil amount previously obtained by the air atomization method into the case of an emulsion, and the supply amount was made constant at 10 L / min on the upper and lower sides. When the coil was unwound after rolling, it was confirmed that seizure had occurred about 17 minutes after the start of steady-state rolling, and the effectiveness of the air atomization method was confirmed.

It is 1st Embodiment of this invention, Comprising: It is a typical block diagram of the rolling mill which implements the lubricating oil supply method of this invention. It is 1st Embodiment of this invention, Comprising: It is a typical block diagram of the rolling mill which implements the lubricating oil supply method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal plate (steel plate) 10 Rolling machine 12 Work roll 14 Backup roll 20 Lubricating oil header 22 Lubricating oil nozzle 24 Cooling water header 26 Cooling water nozzle 28, 29 Drain plate 30 Lubricating oil tank 34 Lubricating oil pump 36 Lubricating oil pressure control valve 40 Compressed Air Tank 46 Air Flow Control Valve 50 Cooling Water Tank 54 Cooling Water Pump 56 Cooling Water Flow Control Valve 60 Lubricating Oil Supply Control Device 62 Plate Speedometer 64, 66 Oil Film Thickness Meter

Claims (4)

In the lubricating oil supply method in cold rolling to supply the lubricating oil stock solution to the roll bite entry side,
Measure the roll peripheral speed of the rolling mill and the sheet speed on the delivery side of the rolling mill to calculate the advanced rate , and spray the lubricant stock solution from the lubricating oil nozzle with a compressed gas so that the advanced rate falls within the set range. Suppose while controlling the lubricating oil supply by jetting and adjusting the air flow rate to the roll bite entry side,
Wherein supplying at least the cooling water to the work rolls at the delivery side of the rolling mill, and removing the cooling water adhering to the roll surface and / or the metal plate surface on the delivery side of the rolling mill work roll exit side draining device Lubricating oil supply method in cold rolling. In the lubricating oil supply method in cold rolling to supply the lubricating oil stock solution to the roll bite entry side,
Measure the oil film thickness on the exit side of the rolling mill with an oil film thickness meter, and spray the lubricating oil stock solution in a mist with compressed gas from the lubricating oil nozzle so that the measured oil film thickness matches the target value. flow rate supplied while controlling the lubricating oil supply amount by adjusting the supplying cooling water to at least the work rolls at the delivery side of the rolling mill, the roll surface of the work roll exit side and / or delivery side of the rolling mill of the metal plate A cooling oil supply method in cold rolling, wherein cooling water adhering to the surface is removed by a draining device. Claims an oil film thickness meter the delivery side of the rolling mill placed in the metal plate the upper and lower surfaces, measured oil film thickness, characterized in that vertically separately control the lubricating oil supply amount of the rolling mill inlet side to match the target value Item 3. A method for supplying lubricating oil in cold rolling according to Item 2 . Install multiple lubricant nozzles along the plate width direction, and install multiple oil film thickness meters along the plate width direction on the exit side of the rolling mill so that the measured oil film thickness at each location matches the target value. 4. The method for supplying lubricating oil in cold rolling according to claim 2 , wherein the amount of lubricating oil supplied to the rolling mill is controlled.

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