JP3103825B2 - Method and apparatus for temper rolling of steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is carried out for the purpose of eliminating the elongation at the yield point, adjusting the surface roughness, correcting the shape, adjusting the surface hardness, etc. of a cold-rolled steel strip (hereinafter referred to as a cold-rolled steel strip). The present invention relates to a temper rolling method and apparatus.

[0002]

2. Description of the Related Art Temper rolling of a cold-rolled steel strip is usually performed by a work roll having a predetermined surface roughness in order to improve the mechanical properties and surface finish of the coil after annealing and to correct the shape. Generally, light rolling of about 0.5 to 2.5% is performed. In particular, the surface finish is adjusted by adjusting the surface roughness of the work roll of the temper rolling mill in consideration of the surface roughness and use specified by the user. There are two types of temper rolling: wet rolling and dry rolling. The wet temper rolling method, in which rolling oil consisting of an aqueous solution containing several percent of oil as a lubricant is supplied between a steel strip and a roll while rolling, is often used. I have.

[0003] Temper rolling using a bright roll having a beautiful surface as a work roll is performed on a tin plate original sheet or a high carbon steel sheet which requires particularly beautiful surface quality, but contains several% of oil as a lubricant. Temper rolling using a wet rolling method that gives about 1-3% elongation in one pass while supplying a temper rolling oil composed of an aqueous solution between a steel strip composed of a high carbon steel or a low alloy steel and a roll. When the process is performed, a phenomenon called "jumping", in which the elongation rate becomes unstable, often occurs, and the quality of the product is deteriorated, which may hinder the rolling operation.
Further, when rolling is performed by supplying an excessive temper rolling oil, poor gloss of the surface of the steel strip occurs, and the product quality is deteriorated.

On the other hand, in the temper rolling by the dry rolling method, the coefficient of friction between the work roll and the steel strip becomes too high, and high elongation rolling in the temper rolling becomes impossible. Further, in the dry rolling method, since the effect of cleaning the surface of the work roll and the steel strip by the temper rolling oil cannot be expected, there is a problem that the adhered foreign matter causes roll flaws or the like and lowers the yield.

Further, as a technique for applying a semi-wet rolling method instead of the conventional dry rolling method, a temper rolling oil is injected between the upper and lower work rolls and the backup roll on the rear surface of the work roll, and the upper rolling is further performed. A method in which rolling oil injected from an oil injection header is discharged to both sides of a work roll by a drain gutter having drain pieces, and only rolling oil necessary for preventing roll scratches is left on the roll surface (Japanese Patent Laid-Open No. 56-56). 74303).

Further, an extremely thin lubricant film of 200 mg / m ² or less is previously formed on the upper and lower surfaces of the steel strip by an electrostatic oiling device or the like, so that the lubricant is drawn in by a wedge effect at the roll bite entrance. A method of rolling a thin steel strip without causing the heat treatment (JP-A-51-30563). An electrostatic oiling device is provided in front of a temper rolling mill. A method in which the oil fog is charged and the oil fog is charged and adsorbed on the surface of the steel strip (JP-A-62-121).
672).

A rotatable ringer roll pressed against the surface of the upper work roll, a wiper in contact with an upper portion of the surface of the ringer roll, and a temper rolling oil are sprayed on the upper portion of the ringer roll. And a nozzle for injecting the temper rolling oil on the outlet side between the lower work roll and the lower backup roll, and thinning the temper rolling oil film on the work roll entrance surface while injecting the temper rolling oil from the nozzle. For forming a temper and performing temper rolling (Japanese Patent Application Laid-Open
191604) has been proposed.

[0008]

SUMMARY OF THE INVENTION The above-mentioned JP-A-56-74 is disclosed.
No. 303, JP-A-60-191604 discloses a method in which a temper rolling oil is injected between an upper and lower work rolls and a backup roll, and squeezed toward the entrance between the upper work roll and the backup roll. Excess temper rolling oil other than the specially-extracted, draining gutter with drainage pieces, ringer roll +
The wiper is caused to flow out to both sides of the work roll, but as shown in FIG. 5, the oil pool formed at the roll bite portion between the work rolls 6a and 6b and the backup rolls 9a and 9b is violently disturbed when the rolling speed increases. .
At this time, as shown in FIG.
The temper rolling oil 12 scatters vigorously from the oil pools at both ends of the width of the work rolls 6a and 6b which are not in contact with the work rolls 9b and wraps around the work rolls 6a and 6b entry side, and further, large oil droplets scattered by the roll centrifugal force. Is rebounded by the housing chock 18 or the like, adheres to the cold-rolled steel strip 3 on the entry side and the work rolls 6a and 6b, and is subjected to temper rolling, thereby causing a problem of surface defects (hereinafter referred to as temper rolling oil unevenness). The temper rolling oil unevenness is a serious defect that not only causes a partial unevenness in gloss on the surface of the cold-rolled steel strip but impairs the appearance, but can also be an irregularity defect. In addition, when the rolling speed is reduced to prevent the scattering of oil droplets, the efficiency becomes low.

Further, the methods disclosed in the above-mentioned JP-A-51-30563 and JP-A-62-121672 disclose a temper rolling method in which no oil pool is formed in a roll bite portion between a work roll and a backup roll. And
No mention is made of any measures against wear powder that significantly impair the cleaning effect of the wear powder, which is a major purpose of the temper rolling oil, and make up for it.

[0010] An object of the present invention is to solve the above-mentioned disadvantages of the prior art, to provide excellent surface properties without requiring a large capital investment, and to improve the quality of temper rolling even in high-speed temper rolling. It is an object of the present invention to provide a method and an apparatus for temper rolling a steel strip that can prevent a strip surface defect.

[0011]

The temper rolling method for a steel strip according to the present invention is characterized in that the temper rolling oil is injected between the upper and lower work rolls and the backup roll on the outlet side of the temper rolling mill while the temper rolling oil is injected. In the method of temper rolling of a steel strip, temper rolling is performed while spraying 0.05 to 0.5 g / m ² of temper rolling oil together with gas. In this way, the temper rolling oil 0.1 with gas is provided between the upper and lower work rolls and the backup roll.
By performing temper rolling while spraying 0.5 to 0.5 g / m ² , oil accumulation in the roll bite portion between the upper and lower work rolls and the backup roll can be minimized,
It is possible to prevent the temper rolling oil from scattering from the end of the work roll to the entry side, to obtain a steel strip having a good surface gloss and having no unevenness in the temper rolling oil at the steel strip edge.

Further, the temper rolling apparatus for a steel strip according to the present invention comprises:
Temper rolling mill that temper-rolls cold-rolled steel strip, and temper of steel strip consisting of nozzles that spray temper rolling oil between upper and lower work rolls and backup rolls on the exit side of temper rolling mill In the rolling device, a spray nozzle for spraying a gas containing the temper rolling oil is provided in place of the nozzle for spraying the temper rolling oil. Thus, by providing a spray nozzle for spraying a gas containing the temper rolling oil in place of the nozzle for injecting the temper rolling oil, the temper rolling oil is supplied in a fine mist between the upper and lower work rolls and the backup roll. And it is possible to eliminate or minimize oil accumulation in the roll bite portion.

Further, the mist-like temper rolling oil supplied to the roll bite portion between the upper and lower work rolls and the backup roll passes through the steel strip width direction uniformly from between the output roll bites and enters the entry side. The temper rolling oil of the thin film reaches between the steel strip and the work roll, performs lubrication as temper rolling oil, and exits to the outlet side. The released temper rolling oil is separated into one that adheres to the surface of the steel strip and is carried away and one that remains attached to the roll. The temper rolling oil remaining on the roll tries to return to the roll bite between the output work roll and backup roll by rotating the roll again.
Since the roll bite portion is constantly sprayed with the mist-like temper rolling oil, oil accumulation gradually occurs in the roll bite portion. Particularly during temper rolling at high speed, this oil pool becomes conspicuous, but by pressing and providing a knife-like blade on the exit side of the upper and lower work rolls and the backup roll, the gap between the exit side work roll and the backup roll is provided. The temper rolling oil remaining on the roll to be returned to the roll bite portion can be removed with a knife-like blade, so that oil accumulation at the roll bite portion can be eliminated or minimized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the cause of the occurrence of oil stain, which is a surface defect due to scattered oil of a temper rolling oil, is a turbulence phenomenon at the time of high-speed rolling of an oil sump in a roll bite portion between a discharge roll and a backup roll. This is because oil droplets due to scattering of the temper rolling oil from both ends of the work roll (positions deviated from the body length of the backup roll) to the entry side are printed on the steel strip surface. To prevent this,
It is necessary that the oil sump in the roll bite portion between the work roll on the exit side and the backup roll be minimized so that oil droplets do not scatter to the entry side of the rolling mill. In the present invention, the temper rolling oil to be supplied is minimized to 0.05 to 0.5 g / m ² ,
By making it uniform, the oil pool at the roll bite portion between the output work roll and the backup roll is minimized. In addition, the temper rolling oil amount is 0.05 to 0.5 g.
/ M ² and was of the is less than 0.05 g / m ² can not be uniformly sprayed over the entire roll width, also, 0.5 g / m
^If it exceeds ² , the amount of the temper rolling oil becomes too large, the oil pool becomes large, and oil droplets due to scattering from both ends of the work roll to the entry side are printed on the steel strip surface.

In the present invention, the temper rolling oil and the gas are supplied to the spray nozzle by a pump capable of adjusting the flow rate of the temper rolling oil and the gas, and the fine, for example, the average droplet diameter is 30 μm.
The following mist-like temper rolling oil is sprayed on the roll bite portion between the output work roll and the backup roll. This spray nozzle is a nozzle having a double structure having an inner nozzle for spraying a temper rolling oil inside and an outer nozzle for injecting a gas to an outer periphery thereof, thereby pressurizing the temper rolling oil and gas to form a nozzle. When the temper rolling oil is atomized by gas and sprayed, extremely small diameter droplets having an average droplet diameter of 30 μm or less can be formed.

The temper rolling oil and gas supplied to the spray nozzle are supplied by a pump capable of adjusting the flow rate and pressure, respectively. In the spray nozzle having such a double structure,
By changing and balancing each pressure,
It is possible to supply an extremely small amount of mist-like temper rolling oil that eliminates or minimizes oil pools in the roll bite portion between the work roll on the exit side of the temper rolling mill and the backup roll. In addition, in order to spray the roll bite uniformly, it is effective to arrange a plurality of nozzles in the roll width direction and position the temper rolling oil spread in the mist state to a degree that it wraps slightly near the roll bite. is there.

In the conventional ordinary injection nozzle, even if the oil pool at the roll bite portion between the output work roll and the backup roll is minimized, the injection amount of the temper rolling oil is determined by the nozzle diameter and the temper rolling oil supply pump. Since it is governed by the pressure, it is difficult to control the flow rate, and at the same time, it is difficult to suppress the oil pool because the flow rate can be reduced only to about several tens of times the amount of the mist temper rolling oil of the present invention even with the minimum flow rate. .

The knife-shaped blades to be arranged on the output work roll and the backup roll are arranged such that the knife-shaped blades are lightly in contact with the rolls over the entire width of the upper and lower work rolls and the backup roll. Since this knife-shaped blade has an effect of removing foreign substances such as rolling powder, even better quality can be obtained if the knife-shaped blade is used together with the supply of the atomized pressure-regulating oil.

[0019]

【Example】

Embodiment 1 The details of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic explanatory view showing an apparatus for carrying out the temper rolling method of the present invention, FIG. 2 is a schematic sectional view showing the structure of a spray nozzle used in the present invention, and FIG. FIG. 4 is a schematic side view showing a condition around a roll bite portion between an upper work roll and a backup roll at the time of temper rolling oil, and FIG. 4 is a schematic side view showing an example of disposition of a knife-like blade of the present invention.

In FIG. 1, reference numeral 1 denotes a pay-off reel for rewinding a cold-rolled coil 2 that has been cold-rolled and then annealed. The unwound cold-rolled steel strip 3 passes through entrance-side tension bridle rolls 4, 4. , Work rolls 6a and 6b of temper rolling mill 5
After the surface skin and the flatness are adjusted by this, it is wound up on the output side reel 8 through the output side bridle rolls 7, 7. Pressure is applied to the work rolls 6a and 6b via backup rolls 9a and 9b by a pressing device (not shown). 10a and 10b are upper and lower work rolls 6a and 6b and a backup roll 9 on the exit side of the temper rolling mill 5.
This is a spray nozzle for spraying the mist-like temper rolling oil 11 on the roll bite portion between a and 9b.

As shown in FIG. 2, the spray nozzles 10a and 10b have an inner nozzle 13 for injecting the temper rolling oil 12,
A nozzle having a double structure having an outer nozzle 15 for simultaneously injecting the gas 14 and the temper rolling oil 12 to the outside thereof.
It can be sprayed as a mist-like temper rolling oil 11 having a size of μm or less. Temper rolling oil 1 to spray nozzles 10a and 10b
2 and the gas 14 are supplied to the inner nozzle 13 and the outer nozzle 15, respectively, by a pump capable of adjusting the flow rate and the pressure. In the spray nozzles 10a and 10b having the double structure,
By changing and balancing the pressure of the temper rolling oil 12 and the gas 14, the oil pool is minimized in the roll bite portion between the upper and lower work rolls 6a, 6b and the backup rolls 9a, 9b on the exit side of the temper rolling mill 5. It is configured to be able to spray and supply a very small amount of the mist-like temper rolling oil 11 as described above. Further, in order to spray the mist refined rolling oil 11 uniformly in the width direction of the roll bite, a plurality of spray nozzles 10a and 10b are arranged in the roll width direction, and the spread mist refined rolling oil 11 is rolled. It is effective to position it so that it wraps slightly in the vicinity of the part.

With the above-described structure, the mist-like temper rolling oil 11 sprayed on the roll bite portion between the upper and lower work rolls 6a, 6b and the backup rolls 9a, 9b on the exit side of the temper rolling mill 5 is shown in FIG. As shown in FIG. 3, the upper and lower work rolls 6a and 6b on the delivery side and the backup rolls 9a and 9
b, the thin-film temper rolling oil 16 that has uniformly passed through the roll bite portion in the width direction of the cold-rolled steel strip 3 and entered the entry side,
It adheres to the upper and lower work rolls 6a, 6b and the backup rolls 9a, 9b. The thin-film temper rolling oil 16 adhering to the upper and lower work rolls 6a and 6b reaches between the cold-rolled steel strip 3 and the upper and lower work rolls 6a and 6b, performs a lubricating action as a lubricating oil, and exits to the outlet side. This tempered rolling oil 16
Are attached to the surface of the cold-rolled steel strip 3 and carried away,
The work rolls 6a and 6b are separated from those that remain attached. The temper rolling oil 16 remaining adhered to the work rolls 6a, 6b and the temper rolling oil 16 remaining adhered to the backup rolls 9a, 9b are output again from the work rolls 6a, 6b and the backup roll 9a, as the rolls rotate.
Although it is attempted to return to the roll bite portion between 9b, since the atomized temper rolling oil 11 is continuously supplied to the roll bite portion by spraying, oil pools gradually occur in the roll bite portion. In particular, at the time of high-speed rolling, since this oil pool becomes conspicuous, it is necessary to prevent this.

In the present invention, as shown in FIG.
Knife-shaped blades 17 are arranged in the entire width of the upper and lower work rolls 6a, 6b and the backup rolls 9a, 9b so as to lightly contact each of the rolls.
b and the backup rolls 9a, 9b, and the output work rolls 6a, 6b and the backup rolls 9a, 9
The temper rolling oil 16 which is going to return to the roll bite portion between b is squeezed out by each knife-like blade 17 and removed, thereby preventing the occurrence of oil accumulation in the roll bite portion. Each of the knife-shaped blades 17 has an effect of removing foreign substances such as rolling powder, and therefore, if performed in conjunction with the supply of the mist-like refining rolling oil 11, more glossy and non-uniform refining rolls can be obtained. A good quality cold rolled steel strip without surface defects can be obtained.

Example 2 As a temper rolled material, a sheet thickness of 1.0 mm and a sheet width of 1010 mm
The high-carbon cold-rolled steel strip after annealing was rolled using a work roll composed of a bright roll having a roll diameter of 520 mm and an average surface roughness Ra of 0.3 μm as shown in FIG. 1 as a spray nozzle. Two nozzles having a diameter of 0.4 mm and having a double structure shown in FIG. 2 are arranged in the roll width direction so as to cover the entire width of the temper-rolled material, and a 7% aqueous solution of an organic lubricating oil is used as the temper-rolling oil. The liquid pressure (temper rolling oil) and the gas pressure (pressurized air) are controlled so that an extremely small amount of oil is formed in the roll bite portion between the upper and lower work rolls and the backup roll. was adjusted to 05~0.5g / m ^2, the knife-like blades as roll barrel full width contacts vertically disposed work roll and the backup roll of the temper rolling mill exit side, attached to the upper and lower work rolls and the backup roll Out A second aspect of the present invention is to change the rolling line speed so that the elongation becomes 0.8% by spraying the mist-like temper rolling oil while squeezing and removing the temper rolling oil to be returned to the roll bite portion of the present invention 2 Temper rolling. The temper rolling of the present invention 1 was performed under the same conditions as those of the present invention 2 except that no knife blade was used. The reason why the rolling line speed was changed in this case is to determine the limit speed at which the unevenness in the temper rolling oil does not occur.

For comparison, in the conventional method 1, a temper rolling oil consisting of a large amount of a 7% aqueous solution of an organic lubricating oil is provided between the high-carbon cold-rolled steel strip and the work roll at the entrance side of the temper rolling mill. Temper rolling was carried out by a wet rolling method of injecting water. As Conventional Method 2, temper rolling was performed by the conventional semi-wet rolling method described above. As Conventional Method 3, temper rolling was performed by a dry rolling method using no temper rolling oil.

The inventions 1 and 2 and the conventional methods 1 to 3
In each case, the state of oil accumulation, the surface gloss of the obtained cold rolled steel strip, the presence or absence of roll flaws, etc., and the state of occurrence of temper rolling oil unevenness were investigated. Table 1 shows the results. In addition,
In the surface gloss column in Table 1, ◎ is extremely excellent, ○ is good, ×
Was evaluated as poor, and in the column for roll flaws, etc., ○ was evaluated as having no roll flaws, and x was evaluated as having roll flaws.

[0027]

[Table 1]

As shown in Table 1, in the conventional temper rolling method 1 in which a large amount of temper rolling oil is injected between the steel strip and the work roll on the inlet side of the temper rolling mill, the steel strip and the work roll are used. During any low speed rolling, a large amount of oil pool was formed, resulting in a steel sheet having a low transfer rate and poor surface gloss. At this time, although the temper rolling oil was scattered, no temper rolling oil unevenness was observed due to the large amount of oil pool. Further, the effect of washing and removing the rolling powder by the temper rolling oil was sufficient, and no quality defects such as roll flaws due to bites of foreign matter were generated. Conventional method 2 which is the conventional semi-wet method
In this case, an oil pocket is formed between the work roll and the backup roll on the exit side, and the film is rolled into a certain thin film between the same roll bite, so that the surface gloss becomes better than the wet rolling method of the conventional method 1. Although no flaws and the like were generated, the oil pool was disturbed at a rolling speed of 150 m / min or more, and oil droplets of the temper rolling oil were scattered on the entrance side, resulting in uneven temper rolling oil. In the conventional method 3 of the dry rolling method, the temper rolling oil was not used, so that the surface gloss of the steel sheet was remarkably excellent, but there was no means for removing the rolling powder, and roll flaws were generated.

On the other hand, according to the first aspect of the present invention, in which a very small amount of mist-like temper rolling oil is sprayed between the output work roll and the backup roll without using a knife-shaped blade, the roll bite portion between the output work roll and the backup roll is provided. The oil pool is extremely small, but a small amount of temper rolling oil is supplied, so there is a certain degree of effect on the removal of rolling powder, there are no roll flaws, etc. The gloss became good. However, in the present invention 1, when the rolling speed is increased and the gas pressure and the liquid pressure are changed to spray and supply the mist-like temper rolling oil so that the oil pool is not formed, the rolling speed is 500
At m / min or more, part of the refining rolling oil that slips from the output roll bite to the input side, adheres to the work roll and the backup roll, and returns to the roll bite portion between the output side work roll and the backup roll again. However, the oil pool gradually increased, and as a result, temper rolling oil unevenness occurred. On the other hand, in the present invention 2 in which a very small amount of mist-like temper rolling oil is sprayed between the output side work roll and the backup roll using a knife-like blade, the rolling speed is 1000 m / mi.
In the case of n as well, the oil pool was kept to a minimum due to the effect of squeezing the temper rolling oil adhered to the work roll and the backup roll by the knife-shaped blade, and no generation of the temper rolling oil unevenness was observed.

[0030]

According to the temper rolling method and apparatus of the present invention, the temper rolling oil is mixed with the gas by using the mist nozzle having a double structure and sprayed as the mist temper rolling oil. In addition to minimizing oil accumulation in the roll bite between the work roll and the backup roll on the side, it also prevents excess temper rolling oil from entering the entry side, so the surface gloss is good and the steel strip edge It is possible to prevent the temper rolling oil unevenness of the part.

In the temper rolling apparatus of the present invention, a knife-shaped blade is provided on the work roll and the backup roll on the exit side, whereby the work roll and the backup roll are adhered to each other by the knife-shaped blade and the temper rolling oil is squeezed out. By this effect, the oil pool is kept at a minimum, high-speed rolling can be performed, and roll flaws caused by wear powder during temper rolling can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an apparatus for carrying out a temper rolling method of the present invention.

FIG. 2 is a schematic sectional view showing a structure of a spray nozzle used in the present invention.

FIG. 3 is a schematic side view showing an oil pool of temper rolling oil around a roll bite portion between an upper work roll and a backup roll during temper rolling by the method of the present invention.

FIG. 4 is a schematic side view showing an arrangement example of a knife-like blade of the present invention.

FIG. 5 is a schematic perspective view showing an oil pool of a temper rolling oil around a roll bite portion in a conventional temper rolling method.

FIG. 6 is a schematic front view from the entry side of a rolling mill, showing a state of a temper rolling oil flowing around from both ends of a work roll to an entry side in a conventional temper rolling method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Payoff reel 2 Cold rolled coil 3 Cold rolled steel strip 4 Inlet tension bridle roll 5 Temper rolling mill 6a, 6b Work roll 7 Outlet bridle roll 8 Outlet reel 9a, 9b Backup roll 10a, 10b Spray nozzle 11 Spray Temper rolling oil 12, 16 Temper rolling oil 13 Inner nozzle 14 Gas 15 Outer nozzle 17 Knife blade

Claims (3)

(57) [Claims] 1. A temper rolling method for a steel strip in which a temper rolling oil is injected between a work roll and a backup roll on the upper and lower sides of a temper rolling mill and a temper rolling is performed. A temper rolling method for a steel strip, wherein temper rolling is performed while spraying 0.05 to 0.5 g / m ² . 2. A temper rolling mill for temper rolling a cold-rolled steel strip, and a nozzle for injecting a temper rolling oil between upper and lower work rolls and a backup roll on the exit side of the temper rolling mill. A temper rolling apparatus for a steel strip, comprising a spray nozzle for spraying a gas containing a temper rolling oil in place of a nozzle for jetting a temper rolling oil, in the temper rolling apparatus for a steel strip. 3. The temper rolling mill for steel strip according to claim 2, wherein a knife-like blade is pressed against upper and lower work rolls and backup rolls of the temper rolling mill.