JP2869231B2 - Rolling method of metal plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling a metal plate, and more particularly to a method for preventing a shape defect called herringbone, which is a problem in cold rolling of a thin hard metal.

[0002]

2. Description of the Related Art In recent years, the demands of customers for the quality of cold-rolled products of metals have become more and more severe, and the efforts of the producers to continuously improve the thickness and shape of products have been continually continued. I have.

On the other hand, as metal sheet products, demands for thin materials such as titanium, titanium alloys, stainless steel, and other hard materials are also increasing. In the cold rolling process of these products, small diameter work rolls may be used. Many.

[0004] In general, in cold rolling of a thin hard material using a small-diameter work roll, in addition to simple shape defects such as edge elongation and medium elongation which occur in ordinary rolling, shape defects called striped streak-like herringbones are caused. Often occurs. Shape defects that occur during normal rolling can be resolved by correcting the work roll deflection using an actuator or the like to secure a flat shape.However, herringbone is a kind of buckling phenomenon, and compensates for work roll deflection. Even if a macroscopic flat shape is ensured, its occurrence cannot be suppressed.

As a method for preventing the generation of herringbone, Japanese Patent Application Laid-Open No. 61-219410 proposes a rolling method for increasing forward tension. Indeed, by making the forward tension during rolling equal to or more than a certain value, it is possible to suppress buckling occurring on the roll bite exit side and reduce the herringbone. However, an increase in the forward tension leads to a risk of breakage of the rolled material (strip). The above problem becomes more serious as the plate thickness becomes thinner because the critical forward tension for preventing the generation of herringbone must be increased. Once a break occurs during rolling, not only is the product damaged, but also labor and time is spent on recovery, resulting in a significant decrease in productivity. In addition, there is a large secondary effect such that a work roll is flawed when the rolled material breaks, and the work roll must be replaced. In order to avoid the breakage of the rolled material, it is necessary to operate while securing the shape at low speed, but especially in the rolling of thin materials, it is necessary to go against the demand to increase productivity by performing high speed operation. Become.

Japanese Unexamined Patent Publication (Kokai) No. 63-224808 discloses a method of suppressing the generation of herringbone by changing the horizontal pass line and giving an outflow angle to the exit side of the rolled material. However, since this method requires additional facilities, there is a disadvantage that the existing line needs to be remodeled and the equipment cost increases.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to produce a metal plate having no herringbone and excellent shape, and the specific purpose is as described in the conventional method. Without giving excessive forward tension
Another object of the present invention is to provide a rolling method that can easily and effectively suppress the occurrence of herringbone and produce a metal sheet without any modification of a current production line.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is to use a roll having at least a portion of a rolled material which is in contact with the edge of a strip spirally polished as a work roll, and forming a rolled material in an advanced region of rolling. Rolling method of a metal sheet characterized by applying an acting shearing force in a direction from the center of the sheet width to the end of the sheet width ”.

In the above-mentioned method of the present invention, a spirally polished roll (hereinafter referred to as a "spiral polishing roll") is a spirally polished roll as shown in FIG. Means role. Although the actual unevenness of the roll surface is extremely fine, the unevenness is extremely fine. However, in FIG. 1 and FIGS.
The surface irregularities are exaggerated. In the roll shown in FIG. 1A, spirals having different inclination directions are attached to the entire barrel with the center of the barrel as a boundary. As shown in FIGS. Various modes of use of the roll are possible.

Usually, in the surface polishing of the roll, the side of the cylindrical grindstone is applied while the roll is being rotated, so that the polishing line is formed substantially at right angles to the axis of the roll. However, if the bottom surface of the grindstone is pressed against the roll surface using a dish-shaped grindstone and the relative position of the roll and the grindstone, the rotation speed of the grindstone, the rotation speed of the roll, etc. are appropriately adjusted, the graph shown in FIG. 3. As shown in FIG. 4, the polished stitch is inclined at a certain angle with respect to the roll axis (this is the helical polishing angle α, and the counterclockwise direction is positive as shown). .

Although the polished eyes are intermittently microscopically, the polished eyes are spirally connected along the outer periphery of the roll macroscopically. Such a roll is referred to as a “spiral polishing roll” in the present invention.

FIG. 2 is a diagram schematically showing a relationship between a roll and a rolled material during rolling. As shown in the figure, the plate thickness t ₁ to t
_{In the} case where the rolled material is rolled to ₂ , if the speed of the rolled material on the roll entry side (point A) is v ₁ and that on the exit side (point B) is v ₂ , then v ₁ <v ₂ . Rolling material speed v is roll peripheral speed V
The point (point N) which is the same as the above is called a neutral point, and from this point forward (the roll exit side) is called the advanced zone, and the rear (the roll entrance side) is called the reverse zone. In the reversing region on the entry side from the neutral point N, the speed v ₁ of the rolled material is smaller than the roll peripheral speed V, so that the rolled material exerts a pulling force toward the roll, and the advanced region on the exit side from the neutral point N In this case, since the speed v ₂ of the rolled material is greater than the roll peripheral speed V, a force acts on the rolled material to pull it back in the roll direction. Due to the directionality and the action of the spiral polishing on the roll surface, as shown in FIG.
Shear force F ₁ in the plate width direction facing in the reverse zone, so that the shearing force F ₂ in the plate width direction outward acts in developed areas.

[0013]

According to the present invention, a detailed examination result of the effect of the abrasive grain of the work roll on the rolled material, that is, the application of a shear force in a predetermined direction to the surface layer of the rolled material by controlling the direction of the abrasive grain. It was made based on the finding that Specifically, by using a work roll polished in a spiral shape, it is possible to change the tension distribution state near the roll bite exit side, and further, by selecting the direction of spiral polishing, the rolled material on the roll bite exit side can be changed. The present invention has been made based on a new finding that buckling can be prevented and generation of herringbone can be effectively suppressed.

The operation of the present invention will be described with reference to the drawings. 1A and 1B are diagrams for explaining the principle of the method of the present invention, in which FIG. 1A is a diagram viewed from the entry side of a rolled material, and FIG. 1B is a plan view. Here, a state in which both the upper roll 1 and the lower roll 2 are rolled using symmetrically spirally polished rolls is shown.

When the upper and lower work rolls are arranged as spiral polishing rolls and rolled as shown in FIG. 1, shearing in the width direction as shown in FIG. The force will act. That is, in the backward movement region of the rolled material (the region where the speed of the rolled material is smaller than the roll speed on the entrance side from the neutral point), the inward shearing force F ₁ from the end to the center of the rolled material, advanced zone on shear forces F ₂ outward in the (area rate of the rolled material is greater than the roll speed at the outlet side from the neutral point) toward the direction of the end portion from the center of the strip is respectively rolled material It will work on the surface and the lower surface. Such a shearing force in the width direction of the sheet is not generated by rolling using a normal polishing roll. That is, F ₁ = F ₂ = 0 during rolling.

[0016] Although detailed reason is not yet known, according to the number of experimental results of the present inventors, on the rolled material in the developed area, the exit side roll bite by the shearing force F ₂ outward acting on a lower surface The stress state of the rolled material immediately after changes and herringbone can be prevented very effectively. In the method of the present invention, it is desirable to perform rolling with a forward tension applied. However, this forward tension may be about the same as the tension in the normal operation of a rolling line.

The shear force applied to the surface layer of the rolled material in the advanced region does not need to cover the entire width of the upper and lower surfaces of the rolled material. That is,
Apply outward shearing force only to both ends of the plate width,
The object can also be achieved by a method in which an outward shearing force is applied to any half or less of the left and right of the sheet width, or an outward shearing force is applied to either the upper surface or the lower surface of the rolled material.

FIG. 3 illustrates some of the embodiments of the present invention that use work rolls with spirally polished barrel ends. In these cases, polishing of the center of the roll is optional.
Fig. 3 (a) shows the case where normal polishing is applied to the center of the roll.
(b) is polished in the direction parallel to the roll axis, (c)
Indicates a case where dull finish is applied. In any of these cases, a shear force outward in the sheet width direction acts on both ends of the rolled material,
The occurrence of herringbone is prevented.

FIG. 4 shows an example in which the polishing state of the upper and lower work rolls is changed. (a) is spiral polishing only on the left and right halves of the upper and lower rolls, and when the rest is normal polishing,
(b) and (c) are cases where a spiral polishing roll is used for only one of the upper and lower ones, and the other is a normal polishing roll. As shown in the following examples, it has been confirmed that each of them is effective in preventing herringbone.

[0020]

EXAMPLES Rolling was performed using a cold rolling mill having a work roll having a barrel diameter of 40 mm under the conditions shown in Table 1, and the rolling method of the present invention and a conventional rolling method were compared.

The materials used were stainless steel of SUS 304 and 430, pure titanium, and annealed cold-rolled sheet of ordinary steel having a C content of 0.01%. SUS 304, 430 and pure titanium are 80μm, 60μm, 30
Cases 1 to 3 shown in Table 1
And for ordinary ropes, from 800 μm
After cold rolling to 0 μm, 320 μm, and 200 μm, cases 1 to 3 shown in Table 1 were rolled. As shown in Table 2, the rolling of Cases 1 to 3 was performed by changing the polishing state of the work rolls and the roll arrangement to the various forms shown in FIGS. 1, 3 and 4 described above. The conditions for spiral polishing are as follows:
The polishing roughness is 0.8 μm in Rmax and the spiral polishing angle α is 40 °. Mineral oil rolling oil (viscosity 1cSt / 40 ℃)
It was used.

The forward tension was changed during rolling, and the critical tension at which herringbone was generated was determined for the conventional example and the present invention example shown in Table 2. The limit tension is the limit value of the tension in the rolling direction (forward tension) applied on the roll exit side during rolling in order to prevent the occurrence of herringbone (if it is more than this,
Forward tension that does not generate herringbone). That is,
As this limit tension is smaller, herringbone can be prevented with a smaller forward tension.

FIGS. 5 and 6 are diagrams showing the relationship between the herringbone generation limit tension and the total rolling reduction for each material. As shown in the drawing, the herringbone generation limit tension of the present invention example is significantly lower than that of the conventional method regardless of the material. That is, according to the method of the present invention, a metal plate having excellent surface properties can be manufactured without generating herringbone even when the forward tension is reduced as compared with the conventional method. In particular, when the upper and lower rolls are symmetrically helically polished using the roll of FIG. 1 (Example 1 of the present invention), the critical tension is lower than that of the conventional method.
1/3 to 1/4. Also, as shown in FIGS. 3 (a) to 3 (c), only the barrel end of the work roll, or FIG.
In the case where only one half of the roll is subjected to spiral polishing as shown in (a), and in the case where one ordinary polishing roll and one spiral polishing roll are used as shown in FIG. 4 (b) and (c), respectively. However, the critical tension was reduced by about 30 to 50% as compared with the conventional method.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

As demonstrated in the examples, according to the method of the present invention, it is possible to reduce the forward tension at the time of rolling as compared with the conventional method, and it is possible to obtain a flat shape without applying an excessive forward tension. , The risk of strip breakage during rolling is eliminated, and the productivity can be greatly improved. Further, the method of the present invention can be carried out only by changing the polishing pattern of the work roll, and does not require modification or change of the rolling line, so that the equipment cost does not increase.

[Brief description of the drawings]

FIG. 1 is a view for explaining the principle of a spiral polishing roll and a rolling method of the present invention, wherein (a) is a view from the entry side of a rolled material, and (b) is a plan view.

FIG. 2 is a diagram showing a relationship between rolled materials during rolling.

3 (a) to 3 (c) are the same as FIG. 1 (a) showing an embodiment of the rolling method of the present invention.

4 (a) to 4 (c) are the same as FIG. 1 (a) showing an embodiment of the rolling method of the present invention.

FIG. 5 is a diagram showing the relationship between the total rolling reduction and the herringbone generation limit tension in Examples of the present invention and Conventional Examples in rolling a stainless steel plate.

FIG. 6 is a diagram showing the relationship between the total rolling reduction and the herringbone generation limit tension in Examples of the present invention and Conventional Examples in rolling of a titanium plate and a carbon steel plate.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihiko Matsudaira 2-12-1, Minatocho, Joetsu-shi, Niigata Japan Naoetsu Works, Japan Stainless Steel Co., Ltd. No. 22 Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Osamu Miyamoto 4-62 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (56) References JP-A 52-114551 (JP) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 1/00-3/00 B21B 27/00

Claims (1)

(57) [Claims] A roll having at least a portion of a rolled material which is in contact with the end of the width of the roll is polished in a spiral shape, and the rolled material is advanced from the center of the width to the end of the width in the advanced region of rolling. A method for rolling a metal plate, wherein a shear force is applied.