JP2726602B2 - Cold rolling method for metal materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a so-called roll cross rolling method in which at least the upper and lower work roll axes are crossed in a plane parallel to a rolling surface. The present invention relates to a method for rolling a metal material having a small difference in glossiness with high efficiency.

[0002]

2. Description of the Related Art In recent years, demands from customers for the quality of rolled sheets of various metals including stainless steel sheets (hereinafter simply referred to as metal sheets) have become increasingly severe.
Among them, stainless steel sheets are required to have particularly high gloss.

[0003] The gloss of the metal plate surface is mainly affected by the amount of lubricating oil introduced between the roll and the metal material during cold rolling. If the amount of the lubricating oil is too large, the surface of the metal material is freely deformed by the hydrostatic pressure, and minute concaves called oil pits are generated, and the glossiness is reduced. On the other hand, if the amount of the lubricating oil is too small, seizure flaws occur.

At present, cold rolling using a rolling mill called Sendzimir mill is generally performed in order to obtain a metal plate having a high gloss. This Sendzimir mill has a small work roll diameter and a low rolling speed, so that an excessive lubricating oil is not introduced into the roll bite, and a metal plate with high gloss can be manufactured. However, the cold rolling by the Sendzimir mill is inefficient because the rolling pass is repeated by the reversal method, and the roll diameter is small, so that the rolling speed is low and the productivity is low.

[0005] Attempts have been made to more efficiently produce a high-gloss metal plate using a tandem rolling mill capable of high-speed rolling. However, when high-speed rolling is performed with a tandem mill having a large roll diameter, there is a problem that the amount of lubricating oil introduced increases and the glossiness decreases. To solve this problem, Japanese Patent Application Laid-Open No. 61-49701 discloses a 150 mm
After performing cold rolling using a tandem rolling mill equipped with a large diameter work roll of φ or more, finish rolling is performed using a Sendzimir mill using a small diameter roll of 100 mm or less as a work roll, and stainless steel with few surface defects Although a cold rolling method for obtaining a thin steel sheet is disclosed, this method requires two types of equipment, a tandem rolling mill and a Sendzimir mill, and finally uses a Sendzimir mill, so that the rolling speed is still limited and the productivity is low. There is a problem that is not improved.

On the other hand, when the metal material is cold-rolled, the lubricating oil supplied does not become the same on the upper and lower surfaces of the metal material, so that the luster of the metal plate differs between the upper surface and the lower surface. is there. Generally, the upper surface rolled with a large amount of lubricating oil has a lower glossiness. Therefore, Japanese Patent Laid-Open No.
No. 17 discloses a method of rolling by changing the passing angle of a metal material. This method is a method of rolling by increasing the bite angle of the upper surface so as to reduce the amount of lubricating oil drawn in. However, there are problems such as the necessity of installing a new device in the rolling mill. there were.

[0007]

SUMMARY OF THE INVENTION The present invention provides a high-efficiency cold rolling of a metal plate having the same excellent gloss as a product produced by low-speed rolling with a Sendzimir mill using a tandem rolling mill with high productivity. It is another object of the present invention to provide a method of rolling without causing a difference in gloss between the upper and lower surfaces.

[0008]

Means for Solving the Problems In the course of research for increasing the glossiness of a metal plate, the inventor of the present invention has determined that the axial direction of a work roll and the
It has been found that the glossiness of the metal plate surface changes depending on the angle between the rolling direction and the direction perpendicular to the rolling direction (hereinafter referred to as the cross angle). It has been found that the glossiness can be made uniform on the front and back of the metal plate by rolling at different angles.

That is, the present invention has the following (1) to (3).

(1) In the plane parallel to the rolling surface, the angles α and β formed by the axial directions of the upper and lower work rolls at right angles to the rolling direction satisfy αβ ≠ 0 and α-β ≠ 0. A cold rolling method for a metal material, comprising: setting a work roll so as to perform roll cross rolling.

(2) The difference in glossiness between the upper and lower surfaces of the metal plate after the roll cloth rolling is measured, and the cold rolling of the metal material to be rolled while adjusting α and β in (1) so that the difference is reduced. Method.

(3) The cold rolling method for a metal material according to (1) or (2), wherein the roll cross rolling is performed while controlling the sum of α and β to be constant in (1).

[0013]

FIG. 1 is a view (plan view) of a state of rolling by the method of the present invention as viewed from above (plan view), and an angle α formed between a direction perpendicular to the rolling direction (a sheet width direction) and an upper work roll is the same. The angle β between the plate width direction and the lower work roll is different. However, the upper work roll and the lower work roll may be inclined in the opposite direction to the plate width direction as shown in this figure, or may be inclined in the same direction. Since the meandering of the metal material accompanying the above becomes large, it is desirable to incline in the opposite direction.

FIG. 2 is a plan view for explaining a normal roll cloth rolling method, and upper and lower work rolls are arranged so as to be symmetrical with respect to the sheet width direction (a state of α = β).

FIG. 3 is a cross-sectional view in the plate width direction for explaining a contact state between a work roll and a metal material.

In normal roll cross rolling, as shown in FIG. 2, an upper work roll 1 and a lower work roll 2 are crossed in a plane parallel to the rolling surface so that their respective cross angles become θ. The metal plate 3 is rolled in the X direction. In this rolling, the direction of the rotational peripheral velocity V _r of the upper work roll 1,
In the direction of the rolling speed V _s of the metal plate 3, there is a deviation of the angle theta, the upper surface of the metal plate 3, sliding the plate width direction between the metal material and the roll (direction Y) occurs. Similarly, the direction of the peripheral rotation speed of the lower work roll 2 also deviates from the direction of the rolling speed of the metal plate by an angle θ. Slip occurs. The shear stress generated at this time acts on the surface of the metal plate 3 in the width direction of the metal plate 3 and smoothes the surface of the metal plate 3 due to the deviation from the polished line of the work roll.

Therefore, as shown in FIG. 3, when roll cross rolling is performed using a roll having a normal (in the circumferential direction of the roll) polishing, for example, the convex portion of the polishing roll of the upper work roll 1 becomes a metal plate. 3 while sliding relatively to the plate width direction Y. At this time, upper work roll 1
Of the metal plate 3 grinds and smoothes the surface of the metal plate 3. The degree of this smoothing changes the gloss of the metal material surface.

If the axial direction of one of the rolls is parallel to the width direction of the sheet, such a grinding effect is lost and excellent gloss cannot be obtained. Therefore, the cross angle between the upper surface and the lower surface must not be zero. That is, the cross angle of the work roll needs to satisfy αβ ≠ 0.

FIG. 4 shows a work roll when a normal roll cloth rolling as shown in FIG. 2 is performed using a roll having a surface roughness Ra of 0.2 μm and rolling speeds of 100 m / min and 400 m / min. The relationship between the cross angle and the glossiness of the surface of the metal material (SUS 430) after rolling was measured and shown in three different levels of lubricating oil supply: 10, 20, and 50 l / min. . It can be seen that, when the cross angle (θ) is in the range of 0 to 1.5 °, the larger the cross angle is, the higher the gloss is, and the larger the amount of lubricating oil is, the lower the gloss is. Here, attention is paid only to the upper surface of the metal plate, but this relationship also holds true for the upper and lower surfaces of the plate. That is, in general, the amount of lubricating oil that is caught at the time of rolling is smaller at the lower surface than at the upper surface, so that the glossiness of the upper surface is inferior to the lower surface. Instead, if the upper work roll is rolled by increasing the cross angle, a plate material having excellent gloss and no difference in gloss between the front and back surfaces can be obtained. That is, if the roll angle is increased by increasing the cross angle of the surface with poor gloss when performing normal roll cross rolling, a metal plate is manufactured without lowering the gloss and having no difference in gloss between the two surfaces. be able to.

By the way, roll cross rolling is originally used as a means for controlling the cross-sectional shape of a rolled plate. If the cross angle is changed during rolling, the shape of the metal plate becomes unstable. I will. However, while keeping the sum of the upper and lower cross angles (α + β, hereinafter referred to as “cross apex angle”) constant, the cross angle of the roll having a lower gloss (in general, the upper roll) in a plane parallel to the rolled material surface. Is changed, the distance between the work rolls at the time of rolling is not substantially changed, so that the glossiness of the upper and lower surfaces can be made substantially equal without breaking the shape of the metal plate.
FIG. 5 shows a state in which the cross angle of the upper and lower rolls is asymmetric while the cross vertex angle is kept constant. This figure shows that the roll arrangement is totally tilted by the angle θu while maintaining the cross vertex angle (α + β = 2θ) of FIG. 2, and the axis indicated by the broken line is the original symmetrical arrangement. (Arrangement in FIG. 2).

In the present invention, when changing the cross angle of the work roll, the work roll may be moved alone or in combination with the backup roll.
The latter is called a pair cross method.

FIG. 6 shows a preferred embodiment of the method of the present invention. As shown in the figure, the glossiness of the upper and lower surfaces of the metal plate after rolling is measured by the glossmeter 4, and the difference in glossiness of the upper and lower surfaces obtained as a result is input to the arithmetic unit 5 and calculated. The cross angle may be changed so as to eliminate the difference. The control device 6 is a device that controls the cross angle according to the change amount of the cross angle obtained by calculating based on the gloss difference.

When the cross angle of the upper and lower rolls is different at the time of rolling, the metal material meanders. Therefore, when the method of the present invention is performed, for example, when applied to a tandem rolling mill, the cross direction of the rolls is set at each stand. It is good to alternately roll.

Next, the effects of the present invention will be described based on examples.

[0025]

Example 1 One-pass, pair-cross cold rolling using a single-stand 4Hi rolling mill in which rolls having a diameter of 400 mm and a surface roughness of Ra (center line average roughness) of 0.1 μm are used as upper and lower work rolls. Was done. As the metal plate, a JIS SUS 430 stainless steel strip with a thickness of 1.0 mm after annealing and pickling is used. The lubricating oil is a synthetic ester-based rolling oil with a viscosity of 60 cSt at 40 ° C at a concentration of 3.0%. An emulsion having a diameter of 5.5 μm was supplied to upper and lower work rolls at 20 liter / min. In addition, the cross angle was based on two conditions of 0.5 ° and 1.0 °, and the upper and lower rolls were arranged in a state of being inclined in a direction symmetric with respect to the width direction of the plate. Further, the cross angle of the upper roll is increased in a plane parallel to the rolled material surface while keeping the cross vertex angle constant.
Rolling was performed by rotating each 0.1 °. The rolling speed was 450 m / min, and the rolling reduction was 20%. The same rolling was performed using a roll having an Ra of 0.3 μm.

At this time, the glossiness of the metal plate after the cold rolling was measured by a glossmeter having an incident angle of 45 ° specified in JIS Z 8741. Table 1 shows the measurement results. In addition, the difference in glossiness between the upper and lower surfaces is evaluated as ◎, less than 10%, ○ as 10% or more and less than 20%, Δ as 20% or more and less than 40%, and × as 40% or more. Also shown in Table 1.

[0027]

[Table 1]

[0028]

Example 2 In the same manner as in Example 1, one-pass pair-cross cold rolling was performed using a single-stand 4Hi rolling mill in which rolls having a diameter of 400 mm and a surface roughness Ra of 0.2 μm were used as upper and lower work rolls. Was done. As the metal plate, a JIS SUS 430 stainless steel strip with a thickness of 1.0 mm after annealing and pickling was used, and the lubricating oil was a synthetic ester-based rolling oil with a viscosity of 60 cSt at 40 ° C at a concentration of 3.0% and an average particle size of An emulsion having a diameter of 5.5 μm was supplied to upper and lower work rolls at 20 liter / min.

As shown in FIG. 6, a gloss meter 4 for measuring the surface gloss of the metal material after rolling was installed on the exit side of the rolling mill, and an air nozzle 7 for draining was installed upstream of the gloss meter.
Based on the gloss difference between the upper and lower surfaces measured by the gloss meter 4 and the gloss value on the upper surface, a difference from the target value was obtained by the arithmetic unit 5 and converted into a signal for controlling the cross angle. The cross angle control device 6 has a mechanism for changing the cross angle of the upper and lower rolls based on the signal.

First, rolling was started with the upper and lower cross angles each set to 0.5 °. Then, reduce the rolling speed from 10m / min
Rolling was performed while changing the cross angle of the upper and lower work rolls so that the difference in gloss between the upper and lower surfaces was reduced while changing the gloss to 500 m / min. In order to minimize the change in shape, the cross apex angle was set to 1.5 ° at the maximum, and the amount of change in the cross angle of the upper and lower rolls was set to be 0.05 °. The gloss difference between the upper and lower surfaces was set to be less than 10%. The transition of the rolling conditions at this time is shown in Table 2, and the measurement result of the glossiness is shown as a solid line in FIG. In addition, the case where the upper and lower rolls are rolled in parallel (cross angle 0 °) is expressed as a broken line, and the gloss of the metal plate when the roll is rolled without changing the control while keeping the cross angle of the upper and lower rolls constant is equal. Indicated by the dashed line.

As can be seen from FIG. 7, when rolled by the method of the present invention, the gloss is superior to that obtained when the upper and lower rolls are parallel, and the upper and lower rolls are crossed. It can be seen that even in the case of rolling, the glossiness is not inferior and the difference in glossiness is smaller than in the case of rolling without changing the upper and lower cross angles constant.

[0032]

[Table 2]

[0033]

Example 3 Rolling was performed under the same operating conditions as in Example 2 while setting the glossiness of the upper and lower surfaces to be 250 or more and controlling the cross angle. Table 3 shows the transition of rolling conditions at that time.
FIG. 8 shows the measurement results of the glossiness. It can be seen that the glossiness can be controlled with high accuracy by adjusting the cross angle of the upper and lower rolls.

[0034]

[Table 3]

[0035]

By performing cold rolling according to the method of the present invention, it is possible to obtain a metal plate having excellent gloss and having no difference in gloss between the upper and lower surfaces. Moreover, since it is possible to perform high-speed rolling using a tandem rolling mill having a large roll diameter, it is possible to produce a highly efficient stainless steel sheet even if the glossiness is particularly important.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state of rolling by the method of the present invention.

FIG. 2 is a plan view illustrating a roll cloth rolling method.

FIG. 3 is a cross-sectional view in the plate width direction for explaining a contact state between a work roll and a metal plate.

FIG. 4 is a diagram illustrating a relationship between a cross angle of a work roll and a surface glossiness of a metal plate.

FIG. 5 is a diagram illustrating a state where the cross angle of the upper and lower rolls is asymmetric in the present invention.

FIG. 6 is a diagram showing an example of a method of measuring the glossiness of upper and lower surfaces and setting a cross angle based on the glossiness difference.

FIG. 7 is a diagram showing a change in glossiness above and below a metal plate when rolling is performed while controlling the cross angle of the upper and lower work rolls.

FIG. 8 is a diagram showing a change in glossiness above and below a metal plate when rolling is performed while controlling the cross angle of upper and lower work rolls.

[Explanation of symbols]

1. 1. upper work roll; Lower work roll, 3. 3. metal plate; Gloss meter, 5. Arithmetic unit,
6. 6. Cross angle control device, Drainer nozzle

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Masahiro Matsuura 4-33, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Inside Sumitomo Metal Industries, Ltd. (72) Inventor: Tohru Kaneko 3 Address: Kashima Works, Sumitomo Metal Industries Co., Ltd. (72) Inventor: Kanji Hayashi 4--22, Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Hiroshima Works, Mitsubishi Heavy Industries, Ltd. 4-62 Shinmachi, Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Hideaki Furumoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima, Hiroshima, Japan Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References 4-71701 (JP, A) JP-B 63-58044 (JP, B2)

Claims (3)

(57) [Claims] In the plane parallel to the rolling surface, the angles α and β formed by the axial directions of the upper and lower work rolls at right angles to the rolling direction are αβ ≠ 0 and α-β ≠ 0. A cold rolling method for a metal material, wherein a work roll is installed so as to satisfy the condition and roll cross rolling is performed. 2. The method according to claim 1, wherein a difference in glossiness between the upper and lower surfaces of the metal plate after roll cloth rolling is measured, and the metal plate is rolled while adjusting α and β so as to reduce the difference. Cold rolling method for metal materials. 3. The method according to claim 1, wherein roll cross rolling is performed while controlling the sum of α and β to be constant.