JP4191838B2 - Cold tandem rolling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cold tandem rolling method and a rolling mill capable of preventing the occurrence of heat scratches and the occurrence of sheet breakage during cold rolling in which rolling is performed while supplying lubricating oil.
[0002]
[Prior art]
Generally, as shown in FIG. 5, the cold tandem rolling mill is in contact with the upper and lower work rolls 1o and 1u, the upper and lower intermediate rolls 2o and 2u that are in contact with the back of the upper and lower work rolls, and the back of the intermediate roll. Rolling mill 4 with upper and lower backup rolls 3o, 3u₁4₂4_Three4_Four4_Five(Here, 5 stands of 6Hi rolling mills) are arranged in series, and each rolling mill 4₁~ 4_Five, The strip material 5a passing between the upper and lower work rolls 1o, 1u is rolled at a predetermined reduction rate while applying the lubricating oil from the lubricating oil supply device 6 in a state where a predetermined tension is applied to produce the strip 5b. It is comprised as follows.
[0003]
In this cold tandem rolling mill, when the speed of the work roll (2o, 2u) is increased or the rolling reduction is increased, it is known that heat scratches are generated in the roll bite of each rolling mill. . This heat scratch is caused by an increase in the interface temperature between the work roll in the roll bite Rb of the rolling mill and the strip material 5a when the strip material 5a is rolled by a rolling mill. It is a seizure flaw caused by metal contact with 5a. The occurrence of this heat scratch varies depending on the rolling reduction, sheet thickness, rolling load, tension, rolling material, lubrication conditions, etc., but is usually likely to occur in a subsequent rolling stand where the rolling load or work roll speed increases. When heat scratch occurs, there is a problem that not only the product surface has a defect and the product yield is lowered, but also the work roll of the rolling stand where the heat scratch has occurred needs to be reassembled, so that the productivity is remarkably lowered.
[0004]
As a method for preventing the occurrence of heat scratch, for example, a method of “using a rolling lubricant having excellent seizure resistance” disclosed in Japanese Patent Laid-Open No. 5-98283, and Japanese Patent Laid-Open No. 56-111505 are disclosed. There are proposed a method of “decreasing the temperature of a plate or a work roll by controlling the amount of coolant” and a method of “decreasing a work roll speed” disclosed in Japanese Patent Laid-Open No. 6-63624. These methods belong to the method of “preventing an increase in the interface temperature between the roll and the rolled material in the roll bite” or “preventing oil film breakage even if the interface temperature in the roll bite increases”. Is. However, the method using rolling lubricant with excellent seizure resistance raises the problem of cost increase, and the method of controlling the plate and roll temperature by controlling the coolant amount causes the problem of responsiveness and reduces the work roll speed. The method has a problem that productivity is lowered.
[0005]
Further, as a method for preventing heat scratch without causing an increase in manufacturing cost and a decrease in productivity, a method of “changing the rolling schedule and tension” disclosed in Japanese Patent Laid-Open No. 60-49802 has been proposed. Yes. However, the method of changing the rolling schedule has a problem that the thickness accuracy is temporarily deteriorated. Also, in the method of changing the tension, naturally, if the value is increased to a high value, the rolling load is reduced and the effect of preventing heat scratching can be obtained. However, if the value is increased, the plate may break, and gradually while watching the rolling situation. When the tension is increased, the responsiveness deteriorates, and there is a problem that heat scratches occur and the plate thickness accuracy deteriorates.
[0006]
In addition, there is also a method of detecting the plate temperature on the rolling stand exit side and controlling the tension based on the temperature, but in this method, tension control is performed when the temperature exceeds the temperature at which heat scratching occurs, There is a problem that heat scratches occur temporarily.
[0007]
[Problems to be solved by the invention]
Generally, when a strip material is cold-rolled by a cold tandem rolling mill, rolling lubricating oil is often supplied and interposed between the strip and the roll. The rolling lubricant used here is mainly an emulsion (oil concentration: about 2 to 30%) type (hereinafter referred to as “emulsion”) in which water and vegetable oil are mixed. They are supplied at the entrance of each rolling stand (rolling mill) or at the entrance of a roll tool.
[0008]
When this emulsion is supplied to the strip material or roll, it separates into water and oil, and the oil adheres to the surface of the strip material or roll (hereinafter referred to as “plate-out”), so that the strip material and roll during rolling are rolled. Efforts have been made to prevent the occurrence of heat scratches by suppressing the increase in coefficient of friction during the period. However, when the rolling speed is 1000 m / min or more, the plate-out amount tends to decrease, and the water in the emulsion is lower in viscosity than the oil when transported to the vicinity of the roll bite in the emulsion state, so the oil is preferred. Then, water enters the roll bite and water is removed from the roll bite inlet. At this time, heat generation and re-emulsification occur due to shearing, the amount of oil introduced and the plate-out amount are reduced, and the friction coefficient is increased. As a result, frictional heat generation increases and the risk of heat scratching increases, which is a hindrance when raising the rolling speed to 1000 m / min or higher to increase productivity.
[0009]
The present invention advantageously solves the problems in the conventional rolling method described above even when performing cold rolling with a cold tandem rolling mill having a rolling stand (rolling mill) that rolls at a rolling speed of 1500 to 2500 m / min. It is an object of the present invention to provide a cold tandem rolling mill and a rolling method that can prevent the occurrence of heat scratches and sheet breakage without causing reduction in productivity, increase in manufacturing cost, and reduction in sheet thickness accuracy.
[0010]
[Means for Solving the Problems]
  The present invention provides the following (1) to(3)It is comprised from this invention.
(1) When performing cold rolling while supplying lubricating oil to the strip material with a cold tandem rolling mill, the rolling speed is 1500 m / min or more, and the rolling stamp is likely to cause insufficient lubrication.ToLeaveInstall a draining device between the rolling lubricant supply device and the roll bite entrance to reduce water intrusion into the roll bite and ensure lubricity.A cold tandem rolling method.
(2)Use lubricating oil of 80 ℃ or higherCharacterized byAs described in (1)Cold tandem rolling method.
(3)PressureLubricating oil is supplied to the work roll from the extended side to increase lubricity.As described in (1) or (2)Cold tandem rolling method.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is applied when cold rolling is performed by a cold tandem rolling mill having a rolling stand that performs cold rolling while supplying rolling lubricant to the strip material at a rolling speed of 1500 m / min or more. A cold rolling method and a cold tandem rolling mill that can stably perform plate rolling at a rolling stand that is prone to lack of lubrication and that can perform cold rolling without the occurrence of heat scratches. By adopting the method, the above-mentioned conventional problems are solved.
(1)Water is drained between the rolling lubricant supply position and the roll bite inlet to prevent water from entering the roll bite, ensuring stable plate-out on the strip material and the roll surface, and preventing the occurrence of heat scratches.
(2)The supply temperature of the rolling lubricating oil is set to 80 ° C. or more to ensure stable plate-out, reduce the coefficient of friction in the high speed region, and prevent the occurrence of heat scratches.
(3) Supply lubricating oil to the work roll from the exit side of the rolling mill to improve lubricity and prevent heat scratching.
  In the present invention, (1) or (1) is combined with either or both of (2) and (3),The plate-out on the strip material and the rolling roll surface is further ensured, and the occurrence of heat scratch is more reliably prevented.
[0012]
The inventors conducted a rolling experiment while changing the temperature of the rolling lubricating oil, and investigated the influence of the rolling speed on the friction coefficient. FIG. 1 shows the relationship between the friction coefficient and the rolling speed when the temperature of the rolling lubricating oil is 60 ° C. and 90 ° C. Based on the experimental results, the following findings were obtained.
A. Increasing the temperature of the rolling lubricant reduces the friction coefficient at high speeds. Although the reverse phenomenon occurs slightly (600 to 1200 m / min) depending on the concentration, supply amount, and oil type of the rolling lubricating oil, the tendency is almost the same.
B. Since heat scratches often occur at a rolling speed of 1800 m / min or higher, the temperature of the rolling lubricant may be controlled by a rolling stand at which the rolling speed is 1500 m / min or higher.
C. The higher the temperature of the rolling lubricant, the better the plate out. At present, the temperature of the rolling lubricating oil is around 60 ° C., but the effect is not remarkable unless it is raised to 80 ° C. or higher.
D. When the above-mentioned emulsion is used as a rolling lubricant, water and oil are separated at the entrance of the rolling roll bite, and heat generation and re-emulsification due to shearing when the separated water is excluded becomes a factor that lowers the plate-out. Sometimes.
The present invention has been made based on these findings.
[0013]
  secondAccording to the present invention, when cold rolling is performed at a rolling speed of 1500 m / min or more while supplying rolling lubricant to the strip material, at least rolling lubrication in a rolling stand (rolling mill) that is liable to cause insufficient lubrication and heat scratches. It is a rolling method of a cold tandem rolling mill that supplies oil at a temperature of 80 ° C. or higher. The rolling lubricating oil supplied to the strip material is supplied at a temperature of 80 ° C. or higher to reduce the coefficient of friction in the high speed range. This ensures stable plate-out and prevents the occurrence of heat scratches.
[0014]
Setting the temperature of the rolling lubricating oil to 80 ° C. or more is effective even in a rolling stand with a rolling speed of less than 1500 m / min, but heat scratching does not occur in this rolling speed region, so an increase in heating cost is considered. In this case, it is not a good idea to set the temperature of the rolling lubricating oil to 80 ° C. or higher. When the temperature of the rolling lubricating oil is less than 80 ° C., the friction coefficient is not sufficiently reduced, and when cold rolling is performed at a rolling speed of 1500 m / min or more, there is a concern that a heat clutch may occur. However, if the supply temperature of the rolling lubricating oil is too high, in addition to an increase in heating cost, the quality is deteriorated due to oxidation and the lubricating ability is lowered. Therefore, the supply temperature is selected in consideration of such a situation. There is a need.
[0015]
When the rolling speed is 1500 m / min to 2500 m / min, the upper limit of the supply temperature of the rolling lubricating oil is about 95 ° C., and a sufficient effect is obtained. Although it is possible to always supply at the upper limit temperature, there is a variation in the coefficient of friction during acceleration / deceleration. It is preferable to control the temperature of the rolling lubricating oil according to the thickness, material), rolling speed, tension, and the like. As this temperature control method, for example, a low temperature oil tank (60 ° C.) and a high temperature oil tank (90 ° C.) are prepared, and the temperature is adjusted by adjusting the mixing ratio of the low temperature oil and the high temperature oil via a mixing device. Alternatively, there is a method of adjusting the temperature of the rolling lubricating oil by arranging a heating device in the rolling lubricating oil supply path.
[0016]
  firstIn the present invention, when cold rolling is performed at a rolling speed of 1500 m / min or more while supplying rolling lubricant to the strip material, at least between the rolling lubricant supply position and the roll bite inlet in a stand where lubrication is likely to occur. This is a cold tandem rolling mill method that drains water to prevent water from entering the roll bite, and drains water between the rolling lubricant supply position and the roll bite inlet to prevent water from entering the roll bite. This ensures stable plate-out on the strip material and roll surface, and prevents the occurrence of heat scratches. This draining is performed in order to prevent the adverse effect of water after the rolling lubricant is supplied to the strip material and the rolling roll and the plate-out is completed. It is.
[0017]
In 3rd invention, lubricating oil is supplied with respect to a rolling roll from a rolling mill delivery side, sufficient plate-out with a rolling roll is ensured, and generation | occurrence | production of a heat scratch is prevented. As the lubricating oil supplied from the rolling mill outlet side, the same lubricating oil as that supplied from the rolling mill inlet side can be used. Although not shown in FIGS. 2, 3, 4, and 5, a cooling water is applied to the work roll so that the cooling water is not easily attached to the plate by applying cooling water from the rolling mill exit side for roll cooling. Needless to say, it has.
[0018]
In addition, you may provide the draining device which removes the water which floats on a strip material as needed also at the exit side of a roll bite. As this draining device, it is desirable to use a device that does not inhibit plate-out. For example, a contact-type roll method or a gas jet or contact-type wiper method may be used. When gas injection is used, the gas may be heated to reduce the temperature drop of the rolling lubricating oil.
[0019]
  The first invention may be combined with the second or third invention,The plate-out on the surface of the strip material and the rolling roll is further ensured, and the occurrence of heat scratch is more reliably prevented. That is, when performing cold rolling while supplying lubricating oil to the strip material, the temperature of the rolling lubricating oil of the rolling stand that performs cold rolling at a rolling speed of 1500 m / min or more and at least tends to cause insufficient lubrication. Is supplied at a temperature of 80 ° C. or higher and drains at the roll bite inlet. In addition, if necessary, lubricating oil can be improved by supplying lubricating oil to the work roll from the rolling mill exit side. As the lubricating oil supply means and draining means, the same means as described above can be used.
[0020]
【Example】
  Embodiments of the present invention will be described below with reference to FIGS.
(1) FIG. 2 shows the first invention of the present invention.Third1 shows an example of equipment arrangement of a cold tandem rolling mill to which the invention of the present invention is applied, and this cold tandem rolling mill basically has the same structure as the cold tandem rolling mill shown in FIG. Upper and lower work rolls 1o, 1u (rolling rolls), upper and lower intermediate rolls 2o, 2u in contact with the back of the upper and lower work rolls, and upper and lower backup rolls 3o, 3u in contact with the back of the intermediate roll 6Hi rolling mill 4 equipped₁~ 4₅Are arranged in series, and in each rolling mill, a strip 5b is manufactured by rolling at a predetermined reduction rate in a state where a predetermined tension is applied to the strip material 5a passing between the upper and lower work rolls. It is configured.
[0021]
In this cold tandem rolling mill, each rolling mill 4₁~ 4_FiveA lubricating oil supply device 6 for supplying rolling lubricating oil to the strip material 5 a is disposed on the inlet side of the slab. The lubricating oil supply device includes a low temperature oil tank 8 and a high temperature oil tank via a mixing device 7. 9 is connected. Each of the low temperature oil tank and the high temperature oil tank is provided with a temperature adjusting device 10, and the rolling lubricating oil 11 accommodated in each tank is always managed at a predetermined temperature. Here, for example, the rolling lubricating oil in the low-temperature oil tank 8 is controlled at 60 ° C., and the rolling lubricating oil in the high-temperature oil tank 9 is controlled at 90 ° C. By mixing at a predetermined mixing ratio by the mixing device 7, the lubricating oil The temperature of the rolling lubricating oil 11 supplied to the supply device 6 can be adjusted to a desired temperature, and the rolling lubricating oil 11 at a predetermined temperature can be supplied from the lubricating oil supply device 6 to the strip material 5a at a predetermined supply amount. .
[0022]
In the figure, 16 is a pump for supplying the rolling lubricating oil 11. Here, the application amount of the rolling lubricant 11 is set for each rolling mill in accordance with the material, size, rolling temperature, and rolling reduction ratio of the strip material 5a to be rolled for each rolling mill. With the amount kept constant, the temperature of the rolling lubricating oil 11 is controlled according to the rolling speed. Therefore, the rolling speed meter 12 is arranged in each rolling mill, the rolling speed is measured, the rolling speed information is input to the arithmetic device 13, and the temperature of the rolling lubricating oil 11 corresponding to the rolling speed is calculated by this arithmetic device. At the same time, the mixing ratio of the rolling lubricating oil 11 from the high temperature oil tank 9 and the low temperature oil tank 8 is calculated, and the flow rate adjustment valve 15 of the high temperature oil tank 9 and the low temperature oil tank 8 is operated via the drive control device 14. Mixing is performed by the mixing device 7, and the rolling lubricating oil 11 is ejected from the lubricating oil supply device 6 at a predetermined temperature, and is supplied to the surfaces of the strip material 5 a and the rolling rolls (work rolls 1 o and 1 u). When the rolling speed is hardly changed, the temperature of the rolling lubricating oil may be set to a constant value for each rolling mill in advance with the rolling speed being constant.
[0023]
  The first invention configured in this mannerThirdBy implementing this invention, the temperature of the rolling lubricant for the strip material 5a and the rolling roll is adjusted according to the rolling speed, and the friction coefficient is reduced particularly in the high-speed rolling region, and the strip material 5a and the rolling roll surface are reduced. It is possible to secure a stable plate-out and prevent the occurrence of heat scratches.
[0024]
  (2) FIG.first2 shows an example of equipment arrangement of a cold tandem rolling mill to which the present invention is applied. This cold tandem rolling mill basically has the same structure as the cold tandem rolling mill shown in FIG. Is. In this cold tandem rolling mill, each rolling mill 4₁~ 4₅A lubricant supply device 6 for supplying the rolling lubricant oil 11 to the strip material 5a is disposed on the inlet side, and a contact roll 17 is disposed as a draining device between the lubricant supply device and each rolling mill. In addition, after the rolling lubricant 11 is supplied to the strip material 5a and the plate-out is completed, draining is performed at the entrance of the roll bite Rb so as to prevent the plate-out from being lowered by the separated water in the roll bite. . This draining is performed in order to prevent the adverse effect of water after the rolling lubricant 11 is supplied to the strip material and the rolling roll to complete the plate-out, and for this purpose, it is performed at the roll bite Rb inlet. It is effective. However, with this alone, it is difficult to secure a sufficient plate-out with the rolling roll, so lubricating oil 19 is supplied to the rolling roll from the exit side of the roll bite Rb to ensure a sufficient plate-out with the rolling roll. It is also preferable to consider this.
[0025]
  Configured like thisfirstBy carrying out the invention, draining is performed between the rolling lubricant supply position and the roll bite entrance, preventing water from entering the roll bite, ensuring stable plate-out on the strip material 5a and the roll surface, Generation of heat scratches can be prevented.
[0026]
Further, in the third invention in which the lubricating oil 19 is supplied from the outlet side of the roll bite, the plate-out with the rolling roll can be more reliably performed, and the rolling roll function can be secured stably for a long time.
[0027]
  (3) FIG.Invention combining the first invention with the second or third inventionBasically, as with the cold tandem rolling mill shown in FIG. 2, the temperature control of the rolling lubricating oil is possible, and as shown in FIG. The draining device 17 is disposed between the rolling mills, draining is performed at the entrance of the roll bite Rb, and the lubricating oil supply device 18 is disposed on the rolling mill exit side. The effect of the above can be obtained at the same time.
[0028]
That is, when cold rolling is performed while supplying the lubricating oil 11 to the strip material 5a, the rolling lubricating oil is used in a rolling mill that performs cold rolling at a rolling speed of 1500 m / min or more and at least tends to cause insufficient lubrication. 11 is supplied at a temperature of 80 ° C. or higher, and drains at the inlet of the roll bite Rb. Further, the lubricating oil 19 is supplied to the outlet side of the roll bite to lubricate the rolling roll. Lubricating oil 19 is supplied from the lubricating oil supply device 18 to the rolling roll so that a sufficient amount of plate-out can be secured on the rolling roll. The details are substantially the contents of the embodiment of FIGS. 2 and 3 and will not be described in detail.
[0029]
  Configured like thisInvention combining the first invention with the second or third inventionBy adjusting the supply temperature of the rolling lubricating oil 11 to the strip 5a material and the rolling roll according to the rolling speed, the friction coefficient is reduced particularly in the high-speed rolling region, and the lubricating oil supply position and the roll are reduced. Drain the water between the entrances of the cutting tool Rb to prevent the separation water from entering the roll cutting tool, to ensure a more stable plate-out on the strip material 5a and the rolling roll surface, and to more reliably prevent the occurrence of heat scratches. Can do. In addition, when the lubricating oil 19 is supplied to the exit side of the rolling mill, the plate-out on the surface of the rolling roll can be ensured more stably, the occurrence of heat scratches can be more reliably prevented, and the rolling roll function can be extended. Stable over time can be secured.
[0030]
In addition, this invention is not limited to said Example. For example, in the above embodiment, a 6Hi rolling mill is applied to a cold tandem rolling mill in which 5 stands are arranged in series. However, a 2Hi to 6Hi rolling mill is arranged in 2 to 8 stands in series. You may apply to an inter tandem rolling mill. Also, the lubricating oil supply devices 6 and 18 and their supply systems (oil supply tank, temperature adjusting device, mixing device, supply pump, etc.) used in the present invention, types of draining devices and their components, rolling speedometers, The control system of these devices, the type of lubricating oil, etc. are changed within a range that satisfies the scope of the claims of the present invention in consideration of the rolling object, the type of rolling mill, scale, arrangement, rolling conditions, etc. There is something.
[0031]
[Experimental example]
(Experimental example 1)
Using a cold tandem rolling mill as shown in FIG. 2, a strip material having a thickness of 2.5 mm and a width of 1240 is rolled at a reduction rate of 30 to 35% per stand to produce a strip having a thickness of 0/35 mm. In each case, each rolling mill 4 with a rolling speed of 1500 m / min._FourThe strip lubricant 5a was supplied with rolling lubricant at a temperature of 80 to 90 ° C. and rolled, and the occurrence of heat scratch was investigated. The results will be described below in comparison with a comparative example in which rolling lubricant is applied at a normal temperature (60 ° C.) and rolled.
[Rolling conditions]
Strip material: Material Carbon steel tinplate
Work roll
Diameter: 460mm
Effective width: 2000mm
Reduction ratio
4₁        4₂        4_Three        4_Four        4_Five
34.8% 31.8% 31.5% 31.6% 32.7%
Rolling speed: 1500-1800m / min
Rolling lubricant (supplied to the entrance of the rolling mill)
Type: Palm oil (concentration 3%) emulsion
Supply temperature: 80 ° C to 90 ° C
Supply amount: 40 liters / min
[0032]
(1) In each rolling mill in which the rolling speed exceeds 1500 m / min, in each experimental example of the present invention that is rolled by controlling the temperature of the rolling lubricating oil in the range of 80 to 90 ° C. according to the rolling speed, No generation of heat scratch was observed, and a good strip could be produced.
(2) On the other hand, in each rolling mill with a rolling speed exceeding 1500 m / min, in the comparative example in which the rolling lubricant was fed by rolling at a temperature of 60 ° C., heat scratching occurred in the fourth rolling mill, Strip qualityCan be securedThere wasn't.
[0033]
(Experimental example 2)
Using a cold tandem rolling mill as shown in FIG. 3, a strip material having a thickness of 2.5 mm and a width of 1240 is rolled at a rolling reduction of 30 to 35% per stand to produce a strip having a thickness of 0/35 mm. In this case, the rolling mill 4 has a rolling speed of 1500 m / min._Four, The rolling lubricant oil of 60 ° C. was supplied to the strip material 5a, and after supply, drained and rolled at the entrance of each rolling mill, and the occurrence of heat scratch was investigated. The results will be described below in comparison with a comparative example in which rolling is performed without applying draining at each rolling mill after application of rolling lubricant.
[Rolling conditions]
Strip material: Material Carbon steel tinplate
Work roll
Diameter: 460mm
Effective width: 2000mm
Reduction ratio
4₁        4₂        4_Three        4_Four        4_Five
34.8% 31.8% 31.5% 31.6% 32.7%
Rolling speed: 1500-1800m / min
Rolling lubricant (supplied to the entrance of the rolling mill)
Type: Palm oil (concentration 3%) emulsion
Supply temperature: 60 ° C
Supply amount: 40 liters / min
Drainer
Contact roll (surface layer made of urethane)
Diameter: 300mm
Pressing pressure: 500kgf
[0034]
(1) In each rolling mill having a rolling speed exceeding 1500 m / min, after supplying a rolling lubricant having a temperature of 60 ° C. at the rolling mill entrance side, draining is performed at each rolling mill inlet and rolling is performed. In the first to fourth rolling mills, no heat scratch was observed. In the fifth rolling mill, extremely mild heat scratches were observed, but generally good strips could be produced.
[0035]
(Experimental example 3)
In the same manner as in Experimental Example 2, after applying rolling lubricating oil having a temperature of 60 ° C. on the inlet side of the rolling mill, draining is performed at the inlet of each rolling mill, and further, lubricating oil having a temperature of 60 ° C. from the outlet side of the rolling mill {(palm In the experimental example of the present invention in which the oil (concentration 3%) emulsion} was supplied (supplied at a supply rate of 2 liters / min), no heat scratch was observed in any of the rolling mills. The improvement was recognized and a good strip could be manufactured.
[0036]
(Experimental example 4)
Using a cold tandem rolling mill as shown in FIG. 4, a strip material having a thickness of 2.5 mm and a width of 1240 is rolled at a reduction rate of 30 to 35% per stand to produce a strip having a thickness of 0.35 mm. In each case, each rolling mill 4 at which the rolling speed becomes 1500 m / min._Four, After supplying rolling lubricant having a temperature of 80 to 90 ° C. to the strip material 5a on the rolling mill entrance side, draining was performed at each rolling mill inlet and rolling was performed, and the occurrence of heat scratch was investigated. The results will be described below.
[Rolling conditions]
Strip material: Material Carbon steel tinplate
Work roll
Diameter: 460mm
Effective width: 2000mm
Reduction ratio
4₁        4₂        4_Three        4_Four        4_Five
34.8% 31.8% 31.5% 31.6% 32.7%
Rolling speed: 1500-1800m / min
Rolling lubricant (supplied to the entrance of the rolling mill)
Type: Palm oil (concentration 3%) emulsion
Supply temperature: 80 ° C to 90 ° C
Supply amount: 50 liters / min
Drainer
Contact roll (surface layer made of urethane)
Diameter: 250mm
Pressing pressure: 500kgf
[0037]
(1) In each rolling mill with a rolling speed exceeding 1500 m / min, after rolling lubricant oil having a temperature of 80 to 90 ° C. is applied to the strip material 5a on the rolling mill entrance side, the rolling is performed by draining at each rolling mill inlet. In the experimental example of the present invention, no heat scratch was observed, and a good strip could be produced.
[0038]
【The invention's effect】
  In the present invention, in a cold tandem rolling mill that easily generates heat scratches and rolls a strip at a rolling speed of 1500 m / min or more,PressureA simple method of draining the rolling mill after applying the lubricant and preventing the adverse effect of the separated water from the emulsion can stably secure the desired amount of plate-out, reducing productivity and manufacturing. It is possible to prevent the occurrence of heat scratch without causing an increase in cost and a decrease in plate thickness accuracy. Also, especially when draining on the rolling mill entry side,The temperature of the rolling lubricating oil to be used is set to 80 ° C. or more to reduce the friction coefficient,Lubricating oil also supplied from the rolling mill exitOrBy doing so, the desired plate-out amount can be secured more stably, and the rolling roll function can be secured stably for a long time.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the temperature of rolling lubricating oil, the rolling speed and the friction coefficient in a cold tandem rolling mill.
FIG. 2 is an explanatory side view showing a structural example of a cold tandem rolling mill according to the present invention.
FIG. 3 is an explanatory side view showing another structural example of the cold tandem rolling mill of the present invention.
FIG. 4 is an explanatory side view showing another structural example of the cold tandem rolling mill of the present invention.
FIG. 5 is an explanatory side view showing an example of the basic structure of a general cold tandem rolling mill.
[Explanation of symbols]
1o Work roll
1u Lower work roll
2o Upper intermediate roll
2u Lower intermediate roll
3o Upper backup roll
3u backup roll
4₁~ 4_Five  Rolling mill
5a Strip material
5b strip
Rb Roll byte
6 Lubricating oil supply device
7 Mixing device
8 Low temperature oil tank
9 High temperature oil tank
10 Temperature control device
11 Rolling lubricant
12 Rolling speed meter
13 Arithmetic unit
14 Drive control device
15 Flow control valve
16 pump
17 Drainer
18 Lubricating oil supply device
19 Lubricating oil

Claims (3)

When performing cold rolling while supplying lubricating oil to the strip material with a cold tandem rolling mill, in a rolling stand where the rolling speed is 1500 m / min or more and lubrication is likely to occur, the rolling lubricating oil supply device and the roll bite inlet A cold tandem rolling method characterized in that a draining device is installed in between to reduce water intrusion into the roll bite and ensure lubricity . The cold tandem rolling method according to claim 1, wherein a lubricating oil having a temperature of 80 ° C or higher is used . Tandem cold rolling method according to claim 1 or 2 lubricating oil from the rolling machine exit side is supplied to the work rolls, characterized in that to increase the lubricity.

Images