JP2003080312A - Reversing cold rolling mill and method for cold-rolling metallic strip using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversing cold strip mill for reducing the surface defects of a metallic strip generated at rolling without generating defective winding at rolling. SOLUTION: The reversing cold rolling mill is composed so as to perform the cold rolling of the metallic strip by arranging a rolling stand in which rolling rolls are incorporated and further arranging spray nozzles for jetting rolling oil with which the rolling oil is jetted to the rolling stand, wiping apparatuses for removing spent rolling oil, deflector rolls and tension reels in this order from the side near the rolling stand on both sides in the strip passing direction to the rolling stand. In this reversing cold rolling mill, spray nozzles for jetting washing liquid are respectively arranged on both sides below the strip passing line to the rolling stand so as to wash the metallic strip and/or the deflector rolls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse type cold rolling mill capable of reducing the surface defects of a metal strip that occurs during rolling due to foreign substances adhering to a deflector roll, and a metal strip cooling using the same. Hot rolling method.

[0002]

2. Description of the Related Art In the cold rolling of a metal strip, when the metal strip surface or roll surface to be rolled is passed or rolled with foreign matter such as abrasion powder, dust, iron powder, etc. adhered, the foreign matter is removed. When the band is rubbed or a foreign substance is caught between the roll and the metal band and pushed into the metal band, the metal band is pushed into the surface and becomes a surface defect product such as a scratch or a scratch, which significantly lowers the product value.

For this reason, the foreign matter adhering to the surface of the rolled metal strip and the surface of the deflector roll is removed by using a wiping device. For example, Japanese Patent Laid-Open No. 2001-137
Japanese Patent No. 936 discloses a reverse type rolling mill equipped with a wiping device as shown in FIG. Here, the cold rolling method in the reverse type rolling mill shown in FIG. 4 will be described. Tension reels 2 installed on both the left and right sides of the rolling stand 1 apply tension to the metal strip S to remove rolling oil from the spray nozzle 11. While being supplied to the roll bite portion, a plurality of passes of cold rolling is performed by the rolling roll 13 reinforced by the reinforcing roll 14 to obtain a predetermined thickness.
At that time, the rolling direction is alternately changed to the right and left for each rolling pass, and the wiping rolls of the wiping devices 4 provided on the left and right sides of the rolling stand 1 are pressed against the metal strips S to remove the used rolling oil. The metal strip S is removed from above.

When the wiping device 4 is not used, the used rolling oil flows along the metal strip S and flows into the left and right tension reels 2. Therefore, the wiping device 4 on both the left and right sides of the rolling stand 1 is used. In general, if the wiping device 4 on the winding side is not used, the coefficient of friction between the metal strips S becomes small and skid occurs, which causes winding failure of the coil C. Reference numerals 9 and 10 in FIG. 4 are plate passing directions.

Reference numeral 12 in FIG. 4 is a purging means, which is a spray nozzle 12 capable of purging rolling oil and the like on the surface of the metal strip S.

[0006]

However, in such a reverse type rolling mill, metal abrasion powder on the upper surface of the metal strip S,
Since foreign matter such as iron powder is removed by the spray nozzle 12, surface defects such as indentation flaws and abrasion flaws can be reduced. Even if the above is removed, a part of the spray liquid falls and does not contribute to the cleaning of the metal strip S, so that the foreign substance removing effect as high as that of the upper surface cannot be obtained. There is also a problem that the foreign matter is pushed into the lower surface of the metal strip when passing through the deflector roll, so that there are more surface defects on the lower surface of the metal strip S than on the upper surface of the metal strip S. In most cases, the surface quality requirements of consumers are the same on the upper and lower surfaces of the metal strip S, and an urgent solution to this problem has been desired.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to prevent the occurrence of winding defects during rolling, and to reduce the surface defects of the metal strip that occur during rolling. An object of the present invention is to provide a cold rolling mill and a method for cold rolling a metal strip using the cold rolling mill.

[0008]

As a result of intensive studies, the inventors of the present invention have used a wiping device capable of removing used rolling oil as in the conventional case, and can further clean the deflector roll and / or the lower surface of the metal strip. By installing the spray nozzles for spraying the cleaning liquid below the left and right threading pass lines with respect to the rolling stand and using them properly during rolling, it is possible to perform rolling without winding defects and when rolling with rolling rolls. The present invention has been made by finding that the number of surface defects generated on the lower surface of the metal strip, which is the lower surface, can be extremely reduced.

The reverse type cold rolling mill of the present invention uses a rolling stand in which rolling rolls are incorporated, and a spraying nozzle for rolling oil injection capable of injecting rolling oil to the rolling rolls in order from the one near the rolling stand. A wiping device capable of removing the finished rolling oil, a deflector roll and a tension reel are arranged on the left and right in the sheet passing direction with respect to the rolling stand, and are configured to perform cold rolling on the metal strip. In the cold rolling mill, below the left and right threading pass lines with respect to the rolling stand,
It is characterized in that spray nozzles for injecting a cleaning liquid are respectively installed so as to be able to clean the deflector rolls. In this case, the cleaning liquid spraying nozzles are two types of nozzles having different cleaning liquid spraying directions, and one nozzle is installed so that the cleaning liquid spraying direction serves as a roll rotation direction counter with respect to the deflector roll. In addition, it is preferable that the other nozzle is installed so that the cleaning liquid spraying direction follows the roll rotation direction, and the cleaning liquid spraying nozzle has a cleaning liquid spraying direction with respect to the deflector roll. More preferably, it is installed so as to be inclined in one of the long directions.

Further, in the present invention, instead of the spray nozzle for cleaning liquid injection in the above-mentioned reverse type cold rolling mill, the spray nozzle for cleaning liquid injection is provided below the left and right sheet passing path lines with respect to the rolling stand. It is also possible to use a reverse type cold rolling mill characterized in that the metal strips are respectively installed so that they can be washed. In that case, the spray nozzles for spraying the cleaning liquid are two types of nozzles having different cleaning liquid spraying directions, and one of the nozzles is installed so that the cleaning liquid spraying direction is a counter for the metal strip passing plate with respect to the metal strip. In addition, it is preferable that the other nozzle is installed so that the cleaning liquid spraying direction follows the metal strip passage direction, and the cleaning liquid spraying nozzle has the cleaning liquid spraying direction that is the metal strip. More preferably, it is installed so as to be inclined to one side in the width direction.

Furthermore, in the present invention, instead of the spray nozzle for cleaning liquid injection in the reverse type cold rolling mill, a spray nozzle for cleaning liquid injection is provided below the left and right sheet passing path lines with respect to the rolling stand. The reverse type cold rolling mill may be characterized in that both the metal strip and the deflector roll are installed so as to be washable. In that case, the spray nozzles for spraying the cleaning liquid are two types of nozzles having different cleaning liquid spraying directions, and one of the nozzles has a cleaning liquid spraying direction as a roll rotation direction counter with respect to the deflector roll, and The nozzle is installed so as to serve as a counter for the metal strip passing plate with respect to the metal strip, and the other nozzle has its cleaning liquid jetting direction following the roll rotation direction with respect to the deflector roll, and the metal strip. Is preferably installed so as to follow the metal strip passage direction, and the cleaning liquid spraying nozzle is inclined such that the cleaning liquid spraying direction is tilted in one of the body length directions with respect to the deflector roll, and More preferably, it is installed so as to be inclined to one side in the width direction with respect to the metal band.

Further, the present invention uses the reverse type cold rolling mill described in any one of the above, wherein the strip passing direction is alternately changed to the left and right for each rolling pass to perform cold rolling on the metal strip. In the inter-rolling method, on the metal strip delivery side in the rolling pass, the metal strip before the rolling is delivered from the tension reel, the cleaning liquid is sprayed from the spray nozzle for cleaning liquid spraying, the deflector roll is cleaned, and / or the rolling is performed. After cleaning the lower surface of the previous metal strip, cold-roll the metal strip before the rolling, and then, on the metal strip winding side in the rolling pass, use the wiping device to remove the used rolling oil and foreign matter. A method for cold rolling a metal strip, characterized in that the spray nozzle for spraying the cleaning fluid is stopped and the spray of the cleaning fluid is stopped and the rolled metal strip is wound by a tension reel.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION First, in the reverse type rolling mill shown in FIG. 1, spray nozzles 5, 6, 7, for injecting cleaning liquid,
The cause of the surface defect of the metal band S that has occurred before installing 8 will be described with reference to FIG. The reverse type cold rolling mill shown in FIGS. 1 and 6 is a Sendzimir rolling mill (also referred to as a 20-high cluster type rolling mill) in which 10 rolls are installed in the upper and lower sides of the rolling stand 1 as shown in the figure. Although the left side of the rolling stand 1 in the sheet passing direction is omitted in FIG. 6, the rolling stand 1 is arranged substantially symmetrically to the right side, and the surface defects of the metal strip S are generated in the same manner.

6 (a) and 6 (b) explain that foreign matter 16 such as metal abrasion powder adhering to the metal strip S causes surface defects such as indentation flaws and abrasion flaws on the lower surface of the metal strip. In the figure, reference numerals 9 and 10 are arrows indicating the passage direction of the metal strip S. Further, 17 indicates foreign matter such as metal abrasion powder adhering to the deflector roll 3, and 15A and 15B indicate rolling oil pools in which used rolling oil is pooled.

As shown in FIG. 6, such a reverse type rolling mill has a rolling stand 1 incorporating a rolling roll 13.
Then, a rolling oil spray nozzle 11 capable of injecting rolling oil, a wiping device 4 capable of removing used rolling oil, a deflector roll 3, and a tension reel 2 are rolled in order from the one closer to the rolling stand 1. Arranged on the left and right sides of the stand 1, while supplying the rolling oil 15 to the rolling rolls 13, the metal strip S can be cold-rolled by alternately changing the sheet-passing direction for each rolling pass. Has been done. In addition, if the rolling oil sump 15A containing the foreign matter is removed by, for example, being swept away in the width direction of the metal strip by the purging liquid sprayed from the purging spray nozzle 12, the upper surface of the metal strip will be considerably damaged. Occurrence can be suppressed.

The inventors of the present invention used this reverse cold rolling mill to cold-roll a stainless steel strip to investigate the cause of surface defects that occur on the lower surface of the metal strip. Cold rolling was performed in the same manner as in the past. At that time, the wiping rolls 4A of the left and right wiping devices 4 were pressed against the metal strip S. here,
The forward rolling path is the direction of arrow 9 and the reverse rolling path is the arrow 1
The direction is 0.

As a result, during the forward rolling pass, the metal strip S
While moving in the direction of arrow 9, while being rolled by the rolling roll 13, the fine metal abrasion powder produced by rolling by the rolling roll 13 passes without being completely removed by the wiping device 4 and passes through the right deflector roll. The foreign matter 16 such as metal abrasion powder, which accumulates in the used rolling oil sump 15B on the entry side and eventually causes surface defects, adheres to the metal strip S, as schematically shown in FIG. 6 (a). And metal strip S
At the same time, it is wound on the right tension reel 2 and the rolling of the rolling pass is completed. Then, during the subsequent reverse rolling pass, when the metal strip S moves in the direction of arrow 10 and is rolled by the rolling rolls 13, it adheres to the metal strip S as schematically shown in FIG. 6 (b). Foreign matter such as worn metal abrasion powder 16
Is sent out from the right tension reel 2 together with the metal strip S, and is rolled together with the metal strip S by the rolling roll 13 and is pushed into the metal strip S to be a push-in flaw, or the right deflector roll regardless of forward or reverse rotation pass. The foreign matter 17 such as metal abrasion powder once adhered to No. 3 is subsequently reattached to the metal band S and becomes a push-in flaw in the same manner as described above, or due to the foreign matter 17 such as metal abrasion powder adhered to the right deflector roll 3 It was found that when the metal strip S passes through the deflector roll 3 and is rubbed and becomes a scratch, a surface defect occurs on the lower surface of the metal strip. Of course, contrary to the case described above, similar surface defects occur on the left side of the rolling stand 1 even during the forward rolling pass.

Therefore, the present inventors diligently studied the cold rolling method, used the wiping device capable of removing the used rolling oil as in the conventional case, and further directed the nozzle to the lower surface of the deflector roll and / or the metal strip. By installing the spray nozzles for spraying the cleaning liquid on the left and right of the rolling pass line on the rolling stand, respectively, and using them appropriately during rolling, rolling can be performed without winding defects, and The surface defects that occur on the lower surface of the metal strip, which is the lower surface during rolling in, can be extremely reduced.

FIG. 1 (a) is a schematic configuration diagram of a reverse type cold rolling mill to which the present invention is applied, and FIG. 1 (b) is shown in FIG.
The spray nozzles 5, 6, 7 for spraying the cleaning liquid shown in (a)
9 is a schematic plan view showing the arrangement of spray nozzles 5 and 6 of FIG. Here, in FIGS. 1A and 1B, the spray nozzles 5, 6, 7, 8 for injecting the cleaning liquid are the deflector rolls 3.
FIG. 6 is a layout diagram in the case where both are installed below the left and right passing path lines with respect to the rolling stand 1 so that both the bottom surface of the metal strip S and the lower surface of the metal strip S can be cleaned, but the present invention is not limited to this. Even if the rolls or the metal strips are installed so that they can be cleaned, both have a considerable foreign matter removing effect, or both may be cleaned by separate spray nozzles. The cleaning liquid spraying spray nozzles 5 and 6 are located near the left deflector roll 3, and the cleaning liquid spraying spray nozzles 7 and 8 are located near the right deflector roll 3 even if the coil outer diameter changes from the minimum to the maximum during rolling. It is provided at a position where it does not come into contact with the metal band S. As shown in FIG. 1B, a plurality of cleaning liquid spraying spray nozzles 5 and 6 are provided along the trunk length direction of the deflector roll 3, and the cleaning liquid spraying spray nozzles 7 and 8 are also the same.

Spray nozzles 5, 6, 7 for jetting the cleaning liquid,
Denoted at 8 is a foreign substance such as metal abrasion powder adhering to the metal band S, once adhering to the deflector roll 3, and then adhering to the deflector roll 3 such as a metal abrasion powder adhering to the metal band S again. It is designed to remove foreign matter such as metal abrasion powder that has caused scratches and the like. As the cleaning liquid sprayed from the spray nozzle for cleaning liquid, rolling oil can be used, and it is desirable to use new rolling oil before it is used for lubrication and cooling, but as long as it has a cleaning function, other It may be liquid. The spray pressure of the cleaning liquid at the spray nozzle for cleaning liquid is 0.02
It is preferably set to 0.8 MPa. The reason for this is that if the spray pressure of the cleaning liquid is less than 0.02MPa, the effect of cleaning foreign matter such as metal wear powder is not sufficient, and if the spray pressure of the cleaning liquid exceeds 0.8MPa, the effect of cleaning foreign matter such as metal wear powder. Is saturated,
This is because the injection energy is wasted.

Further, the wiping roll of the wiping device used in the present invention sandwiches the metal strips vertically with the rolls which are driven by the metal strips to prevent rolling oil from flowing out, and to prevent the surface of the metal strips from flowing out. 3 if there are no scratches
The number of lines is not limited to one, and one is required for each of the upper and lower sides, and the number of lines is not particularly limited as long as there are two or more in total.
The material of the wiping roll used in the present invention is steel, non-woven fabric, urethane rubber or the like, and an appropriate material may be used. The pressing force of the wiping roll in the present invention is
The rolling oil on the surface of the metal strip can be wiped off and removed,
It may be appropriately determined according to the material of the metal strip and the thickness of the metal strip on the entrance side so that winding failure does not occur, and usually 0.02 to 0.1M.
Pa is preferred.

The cold rolling method of the present invention using such a reverse type cold rolling mill will be described with reference to FIGS. 2 (a) and 2 (b). FIG. 2A shows a forward rolling pass in which the arrow 9 direction is the sheet passing direction, and FIG. 2B shows a case of a reverse rolling pass in which the arrow 10 direction is the sheet passing direction. In the present invention, as shown in FIG. 2A, on the metal strip delivery side, the metal strip S before rolling is delivered from the left tension reel, and the cleaning liquid spraying spray nozzles 5, 6 are provided.
After cleaning the left deflector roll 3 and the lower surface of the metal strip S before rolling by injecting a cleaning liquid from the rolling roll 1,
At 3, the metal strip S is cold-rolled. On the other hand, as shown in FIG. 2A, on the metal strip winding side of the rolling pass, the metal strip S after cold rolling by the rolling roll 13 is applied to the wiping roll of the right wiping device. 4A is pressed against the metal strip S to remove the used rolling oil and foreign substances, the spray nozzles 7 and 8 for spraying the cleaning liquid stop the spraying of the cleaning liquid, and the metal strip S after the rolling is wound by the tension reel. I have to.

In the reverse rolling pass following the forward rolling pass described above, the case shown in FIG.
As shown in FIG. 2 (b), the relationship is opposite to that of FIG. Here, on the metal strip delivery side, the reason why the cleaning liquid is sprayed from the cleaning liquid spraying nozzle is that the main cause of the surface defect of the metal strip S is the surface defect generated on the lower surface of the metal strip S as described above. Yes, by cleaning the deflector rolls 3 and the lower surface of the metal strip S before the rolling, as shown in the results of Examples described later, when the deflector rolls 3 are rolled by the rolling rolls 13, they adhere to the metal strip S. The foreign matter 16 such as the metal abrasion powder that is present can be removed from the metal strip S by washing before the foreign matter 16 such as the metal abrasion powder is rolled by the rolling roll 13, or the metal abrasion powder that is adhered to the metal strip S It is possible to prevent foreign matter 16 such as the like from adhering to the deflector roll 3 on the sending side, and to suppress re-adhesion to the metal strip S after that, so that it is possible to reduce indentation flaws. In addition, even if the foreign matter 16 such as metal abrasion powder adhered to the metal band S adheres to the deflector roll 3 on the sending side, cleaning the deflector roll causes scratches or the like. This is because it can be removed by washing before, and it becomes possible to prevent the metal band S from being rubbed and becoming scratches.

Further, in the above description, on the metal band winding side of the rolling pass, the injection of the cleaning liquid from the cleaning liquid spraying spray nozzle arranged near the deflector roll is stopped. The reason is that when spraying the cleaning liquid,
This is because the friction coefficient between the metal strips S on the winding reel 2 on the winding side becomes small, and the coil C suffers from winding failure such as lateral displacement. Coil by other means
The cleaning liquid may be sprayed on the winding side as long as it can prevent the lateral displacement of the cleaning liquid. On the take-up side, the reason why the wiping roll 4A is pressed against the metal strip S and the used rolling oil and foreign matter are removed by the wiping device is the same as in the conventional case. This is to prevent winding defects in and to prevent the occurrence of surface defects. The wiping device on the delivery side generally presses the wiping roll 4A against the metal strip S.

Here, the spray nozzle for spraying the cleaning liquid is
Two types of nozzles having different cleaning liquid jetting directions are provided, the cleaning liquid jetting direction of one nozzle is tilted in the circumferential direction so as to be a roll rotation direction counter with respect to the deflector roll 3, and the metal strip is passed through the metal strip S. It is installed by inclining to the passing plate pass line direction so that it becomes a plate direction counter,
The cleaning liquid jetting direction of the other nozzle is inclined so as to follow the roll rotation direction with respect to the deflector roll 3, and is inclined with respect to the metal band S in the plate passing line direction so as to follow the metal band passing direction. It is preferably installed (see FIG. 2). The reason for this is that if you use a counter for both the roll rotation direction and the metal strip passage direction, it will have the effect of peeling off the adhering foreign matter. This is because it has the effect of suppressing the adhesion of foreign matter, and both effects can further suppress the occurrence of surface defects in the metal strip product. Even if the spray nozzle for spraying the cleaning liquid is installed only as a counter or as a follower in both the roll rotation direction and the metal strip passing direction, it is possible to suppress the occurrence of surface defects in the metal strip product. In FIG. 2, the cleaning liquid spray nozzle is installed so that the cleaning liquid is sprayed into the wedge-shaped space formed by the deflector roll 3 and the metal strip S wound around the deflector roll 3.

Further, it is more preferable that the spray nozzle for spraying the cleaning liquid is tilted in the cleaning liquid spraying direction with respect to the deflector roll in one of the cylinder length directions and in the width direction of the metal strip. For example, in FIG.
Spray nozzles 5 ', 6'for spraying cleaning liquid shown in (b)
Is inclined with respect to the deflector roll 3 by one angle α in the longitudinal direction of the body, but when the cleaning liquid spray nozzle is installed in this way, the effect of removing foreign matter such as metal abrasion powder is improved and removed. This is because foreign matter is flowed out of the line and has the effect of preventing reattachment.

By the way, as a device for removing foreign matter adhering to the deflector roll, Japanese Patent Application Laid-Open No. 10-58016 discloses a reverse rolling mill equipped with the deflecting roll wiping device 20 shown in FIG. Figure 5
The deflector roll wiping device 20 arranged in the reverse type rolling mill shown in FIG.
Foreign matter attached to the deflector roll by the wiper members 22A and 22B attached to the tips of the arms 21A and 21B by pressing one end of the two arms 21A and 21B against the deflector roll 3 in correspondence with the rotating direction of the deflector roll 3. Is configured to be removed. However, when such a deflector roll wiping device 20 is adopted, there is a problem that the wiper members 22A and 22B such as rubber, resin, and felt have a short life, and maintenance work for replacing the wiper members frequently occurs. In addition, if such a wiper member is of a type that comes into contact with the roll, there is a problem that abrasion powder adhering to the metal band S is not removed, which rather promotes the occurrence of the indentation flaw. However, according to the apparatus and method of the present invention, there is no such problem.

In the above description, the spray nozzles 5, 6, 7, 8 for spraying the cleaning liquid are the deflector roll 3 and the metal strip S.
Although the reverse type rolling mill is installed so that both of its lower surfaces can be cleaned, in the present invention, the spray nozzles for spraying the cleaning liquid are provided on the left and right sides of the rolling stand 1 so that only the deflector roll 3 can be cleaned. When each is installed below the plate pass line, or when the cleaning liquid spray nozzle is also installed so that only the lower surface of the metal strip S can be cleaned, the deflector roll 3 and the lower surface of the metal strip S are separately provided. Even when the spray nozzles for spraying the cleaning liquid are individually installed so that the cleaning can be performed, the rolling can be performed without winding defects, and the surface defects on the lower surface of the metal strip can be reduced as compared with the conventional case. In addition,
The cleaning liquid spraying nozzle capable of cleaning only the lower surface of the metal strip S may be provided near the deflector roll 3 between the wiping device 4 and the tension reel 2.

In this case, the cleaning liquid spraying nozzles are two types of nozzles having different cleaning liquid spraying directions.
One nozzle is installed so as to be inclined in the circumferential direction so that the cleaning liquid spraying direction becomes a roll rotation direction counter with respect to the deflector roll, and the other nozzle has its cleaning liquid spraying direction follow the roll rotation direction. It is preferable that the metal strip is installed at an angle to the bottom because it is possible to further reduce surface defects on the lower surface of the metal strip, as will be understood from the examples described later. Further, it is more preferable that the spray nozzle for spraying the cleaning liquid is installed so that the direction of spraying the cleaning liquid is tilted to one side of the deflector roll in the longitudinal direction of the body so that surface defects can be further reduced.

When the cleaning liquid spraying spray nozzle is installed so as to be able to clean the metal strip, the cleaning liquid spraying nozzle is made into two types of nozzles having different cleaning liquid spraying directions, and one nozzle sprays the cleaning liquid. It is installed so that the direction is a counter to the metal strip passage direction with respect to the metal strip, and the other nozzle is set so that the cleaning liquid injection direction follows the metal strip passage direction. It is preferable that the nozzle is installed in the direction of the sheet passing path line because it is possible to further reduce surface defects, as can be seen from the examples described later. On the other hand, it is more preferable to be installed so as to be inclined to one side in the width direction because surface defects can be further reduced.

Of course, the reverse type cold rolling mill to which the present invention is applied is a Sendzimir rolling mill (20-high cluster type rolling mill).
The present invention is not limited to the two-stage reverse type cold rolling mill having a pair of upper and lower rolling rolls, four-stage or six-stage reverse type cold rolling mill, or twelve-stage cluster type reverse type cold rolling mill. It can be applied to various reverse type cold rolling mills.

[0032]

EXAMPLE Using the reverse type rolling mill shown in FIG.
9mm of 4.0mm austenitic stainless steel (SUS304)
After the product was cold-rolled to a thickness of 0.9 mm, bright annealed, and skin-pass rolled, the product was examined for surface flaws after one pass of buffing in the refining process.

At this time, in cold rolling, in each rolling pass, tension is applied to the metal strip S by the tension reels 2 installed on both the left and right sides of the rolling stand 1, and the rolling direction is alternated right and left for each rolling pass. Instead, when cold rolling the metal strip S, the rolling oil 15 is supplied from the rolling oil injection spray nozzle 11 to the roll bite part, and the rolling oil 15 lubricates and cools the metal strip S and performs rolling. Stand 1
The wiping rolls 4A of the wiping device 4 provided on both sides of the metal strip S were pressed against the metal strip S.

In the invention example, at the time of the pass rolling, the cleaning liquid is sprayed from the cleaning liquid spraying spray nozzle arranged near the deflector roll on the metal strip feeding side to clean the deflector roll and / or before the pass rolling. The metal strip was cleaned, and on the metal strip winding side, the spray nozzle for spraying the cleaning liquid arranged near the deflector roll stopped the spray of the cleaning liquid.

In the comparative example, at the time of the pass rolling, the cleaning liquid is sprayed from the cleaning liquid jetting spray nozzle arranged near the deflector roll on the winding side of the metal band to wash the deflector roll and the metal strip before the rolling pass. Further, in the conventional example, the spray nozzle for spraying the cleaning liquid was not installed, neither the cleaning of the deflector roll nor the cleaning of the metal strip was performed in each rolling pass, and the other conditions were the same as those of the above-mentioned invention example.

Here, the presence / absence of surface flaws is evaluated in the range of 1000 mm width × 1000 mm length by rubbing flaws and the like visually and pushing flaws and the like visually by grindstone. The number of occurrences was counted and compared with the ratio of the number of occurrences in the case of the conventional example. In the case of 0 pieces / m ² , it was set to 0. Table 1 also shows the results of investigations of product surface defects in the invention example, the comparative example and the conventional example.

[0037]

[Table 1]

From these results, it can be seen that in the invention example, a metal strip product having extremely few surface defects such as indentation flaws and abrasion flaws can be obtained as compared with the conventional example. Also, in the comparative example,
Lateral slippage became severe on the way, and the rolling had to be stopped.

[0039]

According to the present invention, it is possible to prevent winding defects during rolling and to reduce surface defects of the metal strip such as indentation flaws and rubbing flaws that occur during rolling.

[Brief description of drawings]

FIG. 1A is a schematic configuration diagram of a reverse type cold rolling mill to which the present invention is applied, and FIG. 1B is a schematic plan view showing an arrangement of spray nozzles used in the present invention.

2 (a) and 2 (b) are schematic views showing an operating state of each spray nozzle in the rolling method of the present invention.

3 (a) and 3 (b) are schematic plan views showing another mounting state of the spray nozzle used in the present invention and a spraying state of the spray nozzle.

FIG. 4 is a schematic view showing a cold rolling method in a conventional reverse type rolling mill.

FIG. 5 is an explanatory view showing the operation of a conventional roll wiper.

FIG. 6 is a schematic diagram illustrating a surface defect generation mechanism in a reverse rolling mill before applying the present invention.

[Explanation of symbols]

1 rolling stand 2 reel 3 deflector roll 4 Wiping device 4A Wiping roll 5,6,7,8,11,12 spray nozzle 9, 10 Arrows indicating the passing direction 13 Roll 14 Reinforcing roll 15, 15A, 15B Rolling oil 16, 17 foreign material S metal strip C coil 20 roll wiper 21A, 21B arm 22A, 22B Wiper member

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4E002 AD05 BA03 BD03 BD10 CB03                 4E026 EA02 EA10

Claims (10)

[Claims] 1. A rolling stand incorporating a rolling roll, a rolling oil jetting spray nozzle capable of injecting rolling oil onto the rolling roll in order from the one closest to the rolling stand, and a wiping device capable of removing used rolling oil. In the reverse cold rolling mill, wherein the deflector rolls and the tension reels are arranged on the right and left in the sheet passing direction with respect to the rolling stand so that the metal strip can be cold-rolled, Reverse type cold rolling mills, in which spray nozzles for spraying a cleaning liquid are respectively installed below the left and right passing path lines with respect to the stand so that the deflector rolls can be cleaned. 2. The spray nozzle for spraying the cleaning liquid comprises two types of nozzles having different cleaning liquid spraying directions, and one nozzle is installed so that the cleaning liquid spraying direction serves as a roll rotation direction counter with respect to the deflector roll. The reverse type cold rolling mill according to claim 1, wherein the other nozzle is installed so as to follow the roll rotation direction. 3. The reverse type according to claim 1, wherein the cleaning liquid spraying nozzle is installed so that its cleaning liquid spraying direction is inclined to the deflector roll in one of the body length directions. Cold rolling mill. 4. The cleaning liquid spraying spray nozzle in the reverse type cold rolling mill according to claim 1 is replaced with a cleaning liquid spraying spray nozzle below the left and right sheet passing path lines with respect to the rolling stand. Reverse type cold rolling mills, each of which is installed so that the metal strip can be washed. 5. The spray nozzle for spraying the cleaning liquid comprises two kinds of nozzles having different cleaning liquid spraying directions, and one of the nozzles has a spraying direction of the cleaning liquid serving as a metal strip passing direction counter with respect to the metal strip. The reverse type cold rolling mill according to claim 4, wherein the other nozzle is installed so that the cleaning liquid jet direction follows the direction of the metal strip passing plate. 6. The reverse cooling system according to claim 4, wherein the spray nozzle for spraying the cleaning liquid is installed so that the cleaning liquid spraying direction is inclined to one of the width directions with respect to the metal strip. Rolling mill. 7. The cleaning liquid spraying spray nozzle in the reverse type cold rolling mill according to claim 1 is replaced with a cleaning liquid spraying spray nozzle below the left and right sheet passing path lines with respect to the rolling stand. A reverse cold rolling mill, wherein the metal strip and the deflector roll are both installed so as to be washable. 8. The cleaning liquid spraying spray nozzles are two types of nozzles having different cleaning liquid spraying directions, and one of the nozzles has a cleaning liquid spraying direction as a roll rotation direction counter with respect to the deflector roll. And the metal strip is installed so as to be a counter for the metal strip passage direction, and the other nozzle is such that its cleaning liquid jetting direction follows the roll rotation direction with respect to the deflector roll, and The reverse type cold rolling mill according to claim 7, wherein the reverse type cold rolling mill is installed so as to follow the direction of passage of the metal strip with respect to the metal strip. 9. The cleaning liquid spraying nozzle is installed such that the cleaning liquid spraying direction is tilted in one of the body length directions with respect to the deflector roll and in one width direction with respect to the metal strip. The reverse type cold rolling mill according to claim 7 or 8. 10. A method of cold rolling a metal strip, comprising performing cold rolling on a metal strip using the reverse cold rolling mill according to claim 1, wherein the metal strip in the rolling pass. On the delivery side, the metal strip before rolling is sent out from the tension reel, the cleaning liquid is sprayed from the spray nozzle for cleaning liquid spraying, and the deflector roll is cleaned and / or the lower surface of the metal strip before rolling is cleaned. Cold rolling the metal strip before rolling, then on the winding side of the metal strip in the rolling pass, used rolling oil and foreign matter are removed by a wiping device, and the spray nozzle for cleaning liquid sprays the cleaning liquid. A method for cold rolling a metal strip, comprising stopping and winding the rolled metal strip with a tension reel.