JP3438628B2 - Cold rolling method for metal plate with excellent gloss - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold rolling method for a metal sheet, and more particularly to a cold rolling method suitable for rolling a metal sheet having excellent gloss.

[0002]

Conventionally, a pair of upper and lower rolling rolls (hereinafter,
It is called a roll. ) Cold rolling of a metal sheet using, for example,
For the rolling of stainless steel sheets, which requires the most luster, use a reverse-type rolling mill equipped with a small-diameter roll that is mirror-polished with a roll diameter of about 80 mmφ, and use a low-viscosity (about 10 cSt (40 ° C)) mineral rolling lubrication. It is done at low speed while being oiled.

On the other hand, even in a tandem rolling mill using large-diameter rolls, which is generally less in gloss than the above-mentioned rolling method and has a low production cost, improvement in gloss has been aimed at. Therefore, for example, in Japanese Examined Patent Publication No. 2-14122, a stainless steel sheet supplied to a cold tandem rolling mill is tandem-rolled, and then the tandem-rolled stainless steel sheet is reverse-rolled with a predetermined small-diameter roll. A method of cold rolling a stainless steel sheet is disclosed.

[0004]

However, since reverse rolling performed after tandem rolling incorporates a small diameter roll polished to a mirror surface state and uses low viscosity oil, when high speed rolling is performed, the rolling between the roll and the metal plate is performed. There was a problem of sticking (heat streak). In addition, when high-viscosity oil is used for reverse rolling, the amount of rolling oil drawn into the roll bite increases, the number of oil pits increases, and the problem of reduced gloss and mirror-polished rolls are used.
There is a problem that slip occurs and stable rolling cannot be performed.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and after tandem rolling a metal sheet with a cold tandem rolling mill, further tandem-rolling the metal sheet. In the cold rolling method of performing reverse rolling, it is possible to manufacture a metal plate having a gloss superior to that of the conventional one,
An object of the present invention is to provide a cold rolling method capable of performing stable high speed rolling without causing slip even when rolling using a high viscosity oil.

[0006]

Means for Solving the Problems The inventors of the present invention have completed the present invention as a result of extensive studies aimed at solving the above problems. That is, according to the present invention, a metal plate is tandem-rolled by a cold tandem rolling mill including a plurality of stands equipped with rolling rolls, and then a reverse rolling mill consisting of one stand equipped with rolling rolls is used for a predetermined number of passes. In the method of cold rolling a metal plate for reverse rolling, at least one stand of the cold tandem rolling mill is equipped with a rolling roll having a cross-polished grain and tandem rolling is performed, and then the reverse rolling mill is provided with a circle. Incorporating a rolling roll provided with polishing lines parallel to the circumferential direction, perform the reverse rolling of the predetermined number of passes, or all stands of the cold tandem rolling mill, polishing lines parallel to the circumferential direction After the tandem rolling by incorporating the imparted rolling roll, the reverse rolling machine, incorporating the cross-grinding rolling roll, After performing reverse rolling for at least one pass within the number of passes, or for performing tandem rolling by incorporating a rolling roll having a cross-polishing mark in at least one stand of the cold tandem rolling mill, the reverse rolling mill The method for cold rolling a metal sheet is characterized in that a rolling roll having a cross-polishing mark is incorporated therein and reverse rolling is performed for at least one of the predetermined number of passes.

Further, the cold rolling of the metal sheet is characterized in that the metal sheet to be tandem rolled by the cold tandem rolling mill is a stainless steel sheet which has been annealed, pickled and pretreated after hot rolling. Is the way.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the results of examination by the present inventors,
The gloss depends on the surface roughness of the rolled steel sheet. On the surface of the steel sheet, wrinkled or dented micro defects called oil pits with a depth of a few μm due to the difference in crystal grain deformation, and the depth caused by the transfer of the polishing eyes of the roll called scratches. There are micro defects of about 1 μm. The oil pit defect increases the amount of rolling oil drawn into the roll bite and increases the surface roughness to reduce the gloss when the oil film thickness increases. Further, when the roll roughness is large and the transfer rate thereof increases, the surface roughness of the steel sheet is increased and the gloss of the steel sheet is lowered.

Therefore, first, it will be explained that the gloss of the steel sheet can be improved by rolling using the roll of the present invention provided with the cross-polishing grains which are slanted with respect to the circumferential direction and intersect each other. To do. For example, as shown in FIG. 1, the roll used in the present invention has a polishing mark (referred to as a polishing eye) having an inclination angle θ1 in the clockwise direction with respect to the circumferential direction and an inclination angle θ2 in the counterclockwise direction. The polishing eyes forming the are formed on the surface so as to intersect with each other.

Rolling with a roll having a cross-polished grain increases shear deformation in the rolling direction near the surface of the steel sheet in the roll bite, smoothes the surface of the steel sheet, and reduces scratches due to transfer of roll roughness. ,
The occurrence of oil pits can be reduced due to the effect of suppressing rolling oil inclusion due to the cross-polished grain. Further, since the shear deformation in the rolling direction is large, the steel plate roughness before rolling can be smoothed, and the steel plate roughness after rolling becomes small. Therefore, it is considered that the gloss of the steel sheet can be improved.

Here, FIG. 1 (a) shows a case where the inclination angles θ1 and θ2 of the polishing eyes are made uniform, and the average value of the inclination angles θ1 and the average value of the inclination angles θ2 are substantially the same. Although shown, the polishing eye is not limited to this. As shown in FIG. 1B, the inclination angle θ1 of the polishing eye
And θ2 may be made uniform, and the average value of the tilt angle θ1 and the average value of the tilt angle θ2 may be different. Also, FIG.
As shown in (c), the inclination angles θ1 and θ2 of the polishing eyes may be made non-uniform, and the average value of the inclination angle θ1 and the average value of the inclination angle θ2 may be the same or different.

The average value of the inclination angle of the cross-polished grain of the present invention is preferably 5 to 85 °. The reason for this is that the average value is less than 5 ° of tilt oblique angle cross polishing marks, not improved gloss becomes small smoothing effect, whereas, cross-polishing marks of
If the average value of the inclination oblique angle exceeds 85 °, because gloss rolling oil encapsulation effect of suppressing the cross polishing marks is reduced is not improved. In order to make the average glossiness of the front and back sides 700 (Gs 20 °) or more, the reverse rolling applied to the present invention uses a small diameter roll within the diameter range of 35 to 150 mm, and the viscosity of the rolling oil is 5 to 50 cSt (40
℃), and the roughness Ra of the cross-polished grain is preferably 0.04 to 1.0 μm. Also, the viscosity of the rolling oil is 5 to 20 cSt (40
℃) rolling speed is less than 300 mpm, the viscosity of the rolling oil 20 ~
At 50cSt (40 ℃), the rolling speed is 300mpm or more, so
It is more preferable that the rolling oil has a viscosity of 20 to 50 cSt (40 ° C.).

The tandem rolling applied in the present invention is performed by rolling oil having a viscosity of 10 to 50 cSt (40 ° C.) and a cross mesh roughness Ra of 0.1 to 1.5 μm.
It is given in m. By the way, in the conventional cold rolling, after the rolls provided with grinding marks parallel to the circumferential direction are installed in all the stands of the tandem rolling mill and tandem rolling is performed, the tandem rolled steel sheet is mirror-polished (Ra = 0.04 μm or less)
Since it was a cold rolling method of reverse rolling using a small-diameter roll that was made, it exists on the surface after tandem rolling,
It was impossible to smooth the oil pit defects and scratch defects that reduce the gloss by reverse rolling.

According to a first aspect of the present invention, firstly, a rolling roll having a cross-polished grain is installed in at least one stand of a cold tandem rolling mill to tandem-roll a steel sheet,
A rolling roll with polishing marks parallel to the circumferential direction,
Since it was incorporated in a reverse rolling machine to perform the reverse rolling of the predetermined number of passes, the effect of the cross-grinding, the oil pit defect or scratch defect existing on the surface after the tandem rolling and reducing the gloss. Therefore, the gloss can be improved even if the reverse rolling is performed at high speed using high viscosity oil.

Secondly, the rolling rolls provided with grinding marks parallel to the circumferential direction are installed in all stands of a cold tandem rolling mill to tandem-roll a steel sheet, and then cross grinding marks are applied. Since the rolling roll was incorporated into the reverse rolling machine to perform the reverse rolling of at least one of the predetermined number of passes, oil pit defects and scratch defects existing on the surface after tandem rolling were However, due to the effect of the above-mentioned cross-polishing, the gloss can be improved even if the reverse rolling is performed at high speed using high-viscosity oil.

Thirdly, the rolling roll having the cross-polishing marks is incorporated into at least one stand of a cold tandem rolling mill to tandem-roll a steel sheet, and then the rolling roll having the cross-polishing marks is provided. Was incorporated into a reverse rolling machine to perform reverse rolling of at least one pass within the predetermined number of passes, so that the effect of the cross-polished grain reduces the gloss present on the surface after tandem rolling. It is possible to reduce the oil pit defects and scratch defects, and further improve the gloss even when the reverse rolling is performed at high speed using high viscosity oil due to the synergistic effect with the effect of the above-mentioned cross-polishing in reverse rolling. You can do it.

According to the second aspect of the invention, the steel sheet to be tandem-rolled by the cold tandem rolling mill is a stainless steel sheet which has been annealed, pickled and pretreated after hot rolling, so that it can be rolled by tandem rolling. Wrinkle-like and concave defects on the surface are effectively reduced, and the smoothing of the surface of the cross-polished grain of the first invention and the prevention of encapsulation of rolling oil act synergistically to improve the gloss.

Here, the pretreatment rolling is performed by a rolling mill different from the tandem rolling mill in order to effectively smooth the recesses as compared with rolling by the tandem rolling mill. The rolling mill is annealed,
The pickling line may be continuously installed, but may not be continuously installed. Pretreatment rolling condition is roll diameter 250 ~ 650m
m φ, roll roughness Ra 0.10 to 2.00 μm, rolling speed 100 to 50
0m / min, unlubricated or rolling oil viscosity 10 ~ 50cSt (40 ℃),
It is preferable to use a mineral rolling lubricant having a concentration of 3 to 10%.

The cross-polishing stitch of the present invention has a relative sliding distance of a few mm even in a roll having a small diameter, and a few μ
Since the size of the m oil pit defect is several hundred times or more, it does not have to be continuous. Since the polishing stitches can be intermittent, it is not necessary to mirror-finish the roll surface before polishing, and it is not necessary to deepen the polishing stitches, unlike continuous spiral mark polishing stitches. Can be given as a target.

The tandem rolling mill used in the present invention is
The rolling mill is not limited to the four-high rolling mill, but may be a two-high rolling mill or a six-high rolling mill, and is not limited to the type of rolling mill. The number of stands of the tandem rolling mill can be suitably applied to a tandem rolling mill having 3 to 6 stands. The reverse rolling mill used in the present invention is not limited to the 12-high rolling mill, but may be a 20-high rolling mill or a 6-high rolling mill, and is not limited in the number of rolling stages.

The present invention can also be applied to rolling of metal plates other than steel plates, such as aluminum and copper.

[0022]

Example (Example 1) As shown in C1 to I1 of Table 1,
Using a cold tandem rolling mill consisting of five stands for rolling the steel sheet shown in Fig. 2, hot rolled / annealed / pickled raw material of SUS430 ferritic stainless steel, the viscosity of rolling oil is 40cSt (40 ℃ ), The concentration was 5.0%, the rolling speed was 400 m / min, and the tandem-rolled stainless steel plate was tandem-rolled to a thickness of 1.5 mm. ), The concentration was 5.0%, the rolling speed was 300 m / min, and reverse rolling was performed in 6 passes to a thickness of 0.5 mm. Both tandem rolling and reverse rolling could be performed stably without problems.

Here, the conditions of the roll of the tandem rolling mill are as follows: roll diameter: 600 mm, average value of inclination angle θ1 of cross-grinding, average value of inclination angle θ2: 45 °, inclination angle θ1,
The standard deviation of θ2 was 2 °, the roll roughness Ra was 0.30 μm, and the roll roughness Ra parallel to the circumferential direction was Ra: 0.20 μm. The roll conditions of the reverse rolling mill are as follows: roll diameter: 100 mm, average value of inclination angle θ1 of cross-polished grain, average value of inclination angle θ2: 45 °, standard deviation of inclination angles θ1, θ2: 2 °, roll roughness Ra : 0.10 μm, and the roll roughness Ra parallel to the circumferential direction was Ra: 0.09 μm.

In FIG. 2, the steel sheet 1 is rolled from the left to the right in the figure by a pair of upper and lower rolling rolls 2A to 2E. The rolling stand consisting of five stands includes a pair of upper and lower rolling rolls 2A to 2E, backup rolls 3A to 3E, and coolant nozzles 4A to 4E, respectively. Rolling oil is supplied above and below the rolls 2A to 2E and the steel plate 1 from the coolant nozzles 4A to 4E. Further, in FIG. 3, the steel sheet 1 is alternately rolled in the right direction and the left direction in the drawing by a pair of upper and lower rolling rolls 2 incorporated in one rolling stand. The pair of upper and lower rolling rolls 2 are supported by the intermediate roll 6, and the intermediate roll 6 is supported by the backup roll 3. The rolling oil is applied to the upper and lower sides of the roll 2 and the steel plate 1 through the coolant nozzles 4A to 4A.
Supplied with E.

On the other hand, in the conventional example, as shown in A of Table 1,
Rolls provided with grinding marks (Ra: 0.02 μm) parallel to the circumferential direction were installed in all stands of the cold tandem rolling mill, and tandem rolling was performed at a rolling speed of 200 m / min, followed by mirror polishing. Roll (roll roughness Ra: 0.03 μm)
By incorporating the above into the reverse rolling mill, the viscosity of rolling oil is 10 cS
Reverse rolling was performed for 6 passes at t (40 ° C.) and a rolling speed of 100 m / min. Here, in the reverse rolling of the conventional example, slip occurred when the rolling speed was increased to more than 100 m / min. Therefore, if this speed was exceeded, stable rolling could not be performed.

In the comparative example, as shown in B of Table 1, rolls provided with grinding grains (Ra: 0.02 μm) parallel to the circumferential direction were incorporated in all stands of the cold tandem rolling mill, After tandem rolling, the polishing lines (R
A: 0.09 μm) -provided roll was incorporated into the reverse rolling mill to perform 6-pass reverse rolling. The conditions of the conventional example and the comparative example other than the above were the same as those of the invention example.

After the reverse rolling described above, the steel sheet is subjected to annealing, pickling, and temper rolling, and the glossiness (GS20 °, JIS Z8741
The glossiness measuring method) was measured, and the results are also shown in Table 1.

[0028]

[Table 1]

[0029]

[Table 2]

According to the present invention, as shown in C1 to D5 of Table 1, after at least one stand is assembled with a roll having a cross-polished grain and tandem-rolled, a grain parallel to the circumferential direction is imparted. The above rolls were installed in a reverse rolling machine and subjected to 6-pass reverse rolling, so the gloss was better than that of the comparative example and the conventional example, and the average gloss on the front and back sides was 700 (Gs
20 °) or more.

Further, according to the present invention, as shown by E1 to F5 in Table 1, after the rolls having the grinding marks parallel to the circumferential direction are installed in all stands of the cold tandem rolling mill and tandem rolling is performed. Since the roll with the cross-polished grain was installed in the reverse rolling machine and the reverse rolling was performed for at least one of the six passes, the gloss was better than that of the comparative example and the conventional example, and the average glossiness on the front and back sides was high. Was over 700 (Gs 20 °).

Further, as shown by G1 to I1 in Table 1, after the roll having the cross-polished stitches was incorporated into at least one stand of a cold tandem rolling mill and tandem-rolled, the cross-polished stitches were provided. The roll was installed in the reverse rolling machine and at least one of the six passes was reverse rolled, so the gloss was better than in the comparative example and the conventional example, and the average gloss on the front and back sides was 700 (Gs 20 °). That's it.

Further, when the roll having the cross-polished grain is installed in one stand of the cold tandem rolling mill, it is desirable to install it in the final stand or the first stand. When the roll to which the cross-polishing pattern has been imparted is incorporated into the reverse rolling machine and the first pass is reverse-rolled, it is desirable to use the final pass or the first pass. Further, when the rolls having the cross-polished grain are installed in a plurality of stands of the cold tandem rolling mill, it is desirable to install them in a continuous stand including the final stand or the first stand. When the roll having the cross-polishing marks is incorporated into the reverse rolling mill to reverse-roll a plurality of passes, it is desirable that the rolls be continuous passes including the final pass or the first pass. In addition, since the gloss is highest when the rolls having the cross-polishing marks are incorporated into all the stands of the cold tandem rolling mill, it may be applied within the range of the polishing cost. It is desirable to incorporate a roll having a cross-polished grain into a reverse rolling machine and reverse-roll all passes so that the gloss becomes highest. (Example 2) A stainless steel sheet supplied to the cold tandem rolling mill (the same as in Example 1, SUS430 with a material thickness of 4.0 mm that has been hot rolled, annealed, and pickled) was prepared separately from the cold tandem rolling mill. Perform pretreatment rolling using the provided 6-high rolling mill,
After having a thickness of 3.8 mm, the same tandem rolling and reverse rolling as the rolling conditions shown in Table 1 were performed in the same manner as in Example 1.

Here, in the pretreatment rolling, the diameter of the roll provided with polishing grains parallel to the circumferential direction is 300 mm, and the roughness of the roll is R.
a: When using a roll of 0.20 μm and when cross-polished (average of tilt angle θ1 of cross-polished grain, tilt angle θ2
Mean value of: 45 °, standard deviation of tilt angles θ1, θ2: 1 °,
Roll roughness Ra: 0.50 μm) given roll diameter: 300
Viscosity of rolling oil when using mm roll: 20 cSt
(40 °), rolling oil concentration: 5%, rolling speed: 300 m / min
I gave it in.

After the reverse rolling described above, the glossiness of the steel sheet after annealing, pickling and temper rolling (GS20 °, JIS Z8741
The glossiness measuring method) was measured. Table 2 shows the results when the pretreatment rolling was a roll with polishing eyes parallel to the circumferential direction.
Table 3 shows the results when the roll was a cross-polished mesh.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

By comparing Tables 2 and 3 with the results of Table 1 not subjected to the pretreatment rolling under the same tandem rolling condition and reverse rolling condition, the raw material fed to the tandem rolling is pretreated. It can be seen that the gloss is remarkably improved in the case of applying the pretreatment, as compared with the case of not performing the pretreatment rolling. In addition, when the material to be fed to the tandem rolling is subjected to pretreatment rolling with a roll having cross-grinding marks, it is compared with the case where the pretreatment rolling is performed with rolls having grinding marks parallel to the circumferential direction. It can be seen that the gloss is further improved.

[0041]

According to the present invention, since reverse rolling after tandem rolling can be performed at high speed using high viscosity oil, a metal plate having excellent gloss can be efficiently manufactured. Further, the luster can be further improved by subjecting the material supplied to the tandem rolling to the pretreatment rolling.

[Brief description of drawings]

FIG. 1 is a partially enlarged view of a roll surface conceptually showing the inclination of a cross-polished grain used in the present invention.

FIG. 2 is an explanatory view showing a stand arrangement of the tandem rolling mill used in the present invention.

Is an explanatory view showing a configuration of a Reverse rolling machine used in the present invention; FIG.

[Explanation of symbols] 1 Metal plate (steel plate) 2 rolls (rolls for rolling) 3 backup roll 4 Coolant nozzle 5 Coolant (rolling oil) 6 Intermediate roll

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C23G 3/02 C23G 3/02 (72) Inventor Yoshihiro Kohiro 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Steel In-house (72) Masafumi Hoshino 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (56) References JP-A-5-253604 (JP, A) JP-A-9-76003 (JP) , A) JP-A-2-127903 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21B 1/00-1/46 B21B 27/00 C21D 1/26 C23G 3/02

Claims (4)

(57) [Claims] 1. A metal plate is tandem-rolled by a cold tandem rolling mill having a plurality of stands equipped with rolling rolls, and then a reverse rolling mill having a predetermined number of passes is reverse-milled by a reverse rolling mill having one stand equipped with rolling rolls. In the method for cold rolling a metal plate to be rolled, in at least one stand of the cold tandem rolling mill, a rolling roll having a cross-polished grain is incorporated and tandem rolling is performed, and then the reverse rolling mill is used to incorporating a rolling roll of parallel polishing marks in the direction is applied, the cold rolling process of metal plate, wherein the TURMERIC line reverse rolling of the predetermined number of passes. 2. A plurality of metal plates provided with rolling rolls.
Tandem rolling with a cold tandem rolling mill consisting of a stand
And then a one-stand river with rolling rolls
Of a metal plate that is subjected to a predetermined number of passes of reverse rolling on a rolling mill.
In the cold rolling method, all stands of the cold tandem rolling mill are flattened in the circumferential direction.
By incorporating a rolling roll that has been subjected to fine polishing,
After modem rolled, the reverse rolling mill, incorporating the rolling rolls which cross polishing marks <br/> has been applied, the predetermined path
Cold rolling process characteristics and to Rukin genus plate to make a reverse rolling of at least one pass of the count. 3. A plurality of metal plates provided with rolling rolls.
Tandem rolling with a cold tandem rolling mill consisting of a stand
And then a one-stand river with rolling rolls
Of a metal plate that is subjected to a predetermined number of passes of reverse rolling on a rolling mill.
In the cold rolling method, At least one stand of the cold tandem rolling mill
Incorporate a rolling roll with loss polishing
After dem rolling, the reverse rolling machine
Incorporating a rolling roll provided with, the predetermined path
Performing at least one pass of reverse rolling
A method for cold rolling a metal sheet, comprising: 4. Tandem rolling with the cold tandem rolling mill
The metal plate to be annealed, pickled, and pretreated after hot rolling
Claims characterized in that it is a stainless steel plate that has been subjected to
Item 4. A cold rolling method for a metal plate according to any one of Items 1 to 3.