JPH06170406A - Manufacture of metallic sheet small in edge drop - Google Patents

Abstract

PURPOSE:To manufacture a metallic sheet small in edge drop without generating shape inferiority. CONSTITUTION:A metallic sheet 3 is cold-rolled with work rolls 1, 2 having a spiral grinding mark and a taper at parts in contact with plate width end parts of a rolled stock, inward shearing force in the sheet width direction is actuated to roll the stock in the backward area of rolling or friction coefficients between work rolls 1, 2 and the metallic sheet 3 are changed toward the axial direction of the work rolls having tapers at the contact parts with the sheet width end parts of the rolled stock to carry out roll cross rolling and inward shearing force in the sheet width direction is actuated to roll the stock. In this way, it is possible to manufacture a metallic sheet small in edge drop without generating shape inferiority. Further, cracks and breaks of the metallic sheet occurring in a rolling time can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling method for producing a metal sheet having an excellent sectional shape and a flat shape.

[0002]

2. Description of the Related Art In recent years, the demands of customers for the properties of metal sheets of various materials manufactured by rolling (hereinafter referred to as "rolled sheets") have become more and more stringent, and sheet thickness and sheet shape have become higher. Accurate control is desired.

Generally, when a metal plate is rolled, the work roll is flatly deformed by receiving a reaction force from the metal plate. However, this amount of deformation sharply decreases near the edge of the plate width. At the same time, at the edge of the strip width, plastic flow of the material occurs because there is no restraint force outward in the sheet width direction, so as shown in Fig. 1 (a), the thickness of the strip at the edge of the strip width is A shape defect called edge drop that sharply decreases occurs. In order to give the precision of the plate thickness required as a product to the rolled plate in which this edge drop has occurred, it is necessary to perform a process called trimming, which cuts off the plate end, and therefore reduces production efficiency and yield. Invited.

As a method of preventing the occurrence of this edge drop, there is known a method of rolling using a work roll (hereinafter referred to as a taper roll) whose end portion is processed into a tapered shape as shown in FIG. According to this method, the roll deformation is offset by the taper, and as shown in FIG. 1 (b), the rolling can be performed without deforming the width end of the metal plate.
It is possible to prevent the occurrence of edge drops. In addition to rolling by using taper rolls on the top and bottom, for example, a method using taper rolls on only one of the top and bottom (Fig. 3 (a))
Alternatively, there is a method (Fig. 3 (b)) in which rolls having a taper process only on one side end are symmetrically arranged vertically and the work rolls are rolled while shifting according to the plate width. In addition,
In these figures, for convenience, the work roll is not deformed due to the reaction force of the metal plate, but in reality, the material to be rolled (metal plate) has a rectangular cross section.

On the other hand, when the metal plate is rolled, there is no restraint in the width direction at the end portion, so that the metal plate is outward in the width direction (center portion → end portion).
Plastic flow occurs. Therefore, although the above method can suppress the occurrence of edge drop, the elongation of the central portion becomes larger than that of the plate edge portion, excessive tension is generated only at the edge portion, and depending on the conditions, the edge portion There is a problem that the shape deteriorates.

In recent years, in order to control the plastic flow in the width direction, a rolling mill of the type in which work rolls are bent in the horizontal direction (usually called Minimum-Edgedrop mill, abbreviated as ME mill) has been developed and put into practical use. (Plasticity and processing, Vol.
31-352 (1990), pages 632-638, the 39th Joint Conference on Plastic Workings, pages 593-596). The rolling mill is a rolling mill for offsetting a work roll having an extremely small diameter, bending it horizontally by a support roll, and controlling the edge drop. Four
As shown in (b) and (c), by bending the work roll in the horizontal direction, frictional force is generated in the strip width direction, and it is shown that the plastic flow during rolling of the material changes in the width direction. ing. As a result, it is suggested that by suppressing the deviation in elongation in the width direction, it is possible to change the plate thickness distribution in the width direction while maintaining the shape of the rolled material in a good condition.

FIG. 4 is a plan view showing the horizontal deflection of the roll, and the arrow (→) in the drawing shows the direction of the roll rotation vector. 4A is a state in which the roll is not deflected, FIG. 4B is a state in which the roll is deflected in the rolling direction, and FIG. 4C is a state in which the roll is deflected in the rolling direction. in this way,
As shown in Fig. 4 (b) or (c), the roll direction vector is inward or outward, compared to normal rolling, and the velocity vector in the strip width direction is different, so friction in the strip width direction A force is generated, causing plastic flow of the material.
However, this method requires a special roll arrangement and large-scale auxiliary equipment for bending the roll, and
It is difficult to control the roll deflection amount, and it is also difficult to increase the roll deflection amount. Therefore, it is extremely difficult to arbitrarily control the plastic flow of the material in the plate width direction.

In addition, rolling was performed using a work roll proposed earlier by the applicant of the present invention, in which at least a portion in contact with the plate width end of the rolled material was spirally polished, and rolled into a rolled material in the advanced rolling region. A method of applying a shearing force from the center of the width to the end of the plate width (Japanese Patent Application No. 3-310307), in which the upper and lower work rolls are used alone or as a pair with a backup roll, and intersect in a plane parallel to the rolling surface. In a method of rolling a metal plate (in the present specification, both are collectively referred to as "roll cloth rolling"), a method of rolling by changing the friction coefficient between the work roll and the metal plate in the axial direction of the work roll. (Japanese Patent Application No. 4-252392). Both of them are methods of applying shearing force in the plate width direction to prevent the occurrence of defective shapes.

[0009]

In various cold rolling methods for controlling the edge drop, a large tensile force acts in the rolling longitudinal direction in the vicinity of the plate end, so that the rolled material breaks and the plate end However, there is a problem in that the defective shape occurs.

An object of the present invention is to prevent the occurrence of shape defects and plate breakage by a relatively simple method in a rolling method for controlling edge drop.

[0011]

The gist of the present invention resides in the following (1) and (2).

(1) A metal roll is rolled using a work roll having a spiral grind on the surface and a taper at a portion in contact with the plate width end of the rolled material, and the plate width is set in the backward travel region of the rolling. A method for manufacturing a metal plate having a small edge drop, which is produced by applying a shearing force inward in the direction of rolling.

(2) By using a work roll having a taper at a portion in contact with the plate width end of the rolled material, the coefficient of friction between the work roll and the metal plate is changed in the axial direction of the work roll. Roll roll cross rolling is performed, and a metal plate with a small edge drop is produced by applying a shearing force inward in the plate width direction and rolling.

[0014]

[Action]

(A) A method of applying a shearing force in the plate width direction of the material will be described.

1) Rolling is performed by using a work roll having a spiral-shaped abrasive grain.

The roll having a spiral-shaped abrasive grain means a roll having abrasive grains in a spiral shape, as shown in FIG. 5 (a). The actual unevenness formed on the surface of the roll by polishing is extremely fine, but in FIG. 5 and FIGS. 6 and 7 described later, the surface unevenness is exaggerated for convenience of explanation. FIG. 5 (a), FIG. 6 and FIG. 7 are views seen from the rolling-out side. Although this roll has spirals of different inclination directions attached to the entire barrel with the center of the barrel as a boundary, as shown in FIGS. 6 and 7, there are various modes for the spiral polishing state and the use of the spiral polishing roll. Is possible.

The polishing stitches are microscopically discontinuous, but macroscopically they are spirally connected along the outer circumference of the roll. Such a roll is referred to as a "spiral polishing roll" in the present invention.

FIG. 8 is a diagram schematically showing the relationship between rolls and rolled material during rolling. As shown in the figure, plate thickness t ₁ to t ₂
If the rolling speed at the roll entry side (point A) is v ₁ and that at the exit side (point B) is v ₂ , then v ₁
<V ₂ . The point where the speed v of the rolled material becomes the same as the roll peripheral speed V (point N) is called the neutral point, and from this point the front (roll exit side) is called the advanced zone and the rear (roll entrance side) is called the reverse zone. In the backward travel area 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, a force that pulls toward the roll acts on the rolled material, and in the advanced region on the exit side from the neutral point N, the speed v _{2 of the} rolled material is larger than the roll peripheral speed V, The rolled material has a force that pulls it back in the roll direction. Due to these directivities and the action of the spiral grinds on the roll surface, a shearing force acts on the rolled material inward or outward in the plate width direction.

That is, it is possible to apply a shearing force in the plate width direction of the metal plate by using a work roll that has been spirally polished and selecting the direction of spiral polishing.

The shearing force applied to the surface layer portion of the rolled material in the reverse travel region does not have to extend to the entire width of the upper and lower surfaces of the rolled material. That is,
In the present invention, the inward shearing force is applied only to both ends of the strip width, the inward shearing force is applied to either left or right half or less of the strip width, either the upper surface or the lower surface of the rolled material. The purpose can also be achieved by a method in which an inward shearing force is applied to.

FIG. 6 shows some combinations of work rolls in which both ends of the barrel (including a portion in contact with the end of the plate width) are spirally polished. In these cases, polishing of the central part of the roll is optional. 6A shows the case where the central part of the roll is subjected to normal polishing, FIG. 6B shows the case where the central part of the roll is brightly polished into a mirror surface, and FIG.
In any of these cases, a shear force inward in the plate width direction acts on both ends of the rolled material, and plastic flow outward in the plate width direction can be prevented.

FIG. 7 shows an example in which the polishing states of the upper and lower work rolls are changed. (a) is a case where spiral polishing is applied only to the left and right halves of the upper and lower rolls, and the remaining portion is normally polished,
(b) and (c) show the case where the spiral polishing roll is used for only one of the upper and lower rolls and the other is used as a normal polishing roll. When metal plates are rolled by combining work rolls in this manner, at least both ends of the rolled material work in the widthwise inward shearing force, which causes plastic deformation in the widthwise outward direction, which is one of the causes of edge drop. The flow can be prevented.

2) In roll cross rolling, rolling is performed by changing the friction coefficient between the work roll and the metal plate in the axial direction of the work roll.

FIG. 9 shows a case where roll cross rolling is performed at a cross angle θ without changing the friction coefficient between the upper work roll and the upper surface of the metal plate and the lower work roll and the lower surface of the metal plate in the axial direction of the work roll. 2 shows the relationship between the metal plate and the upper and lower work rolls. 9 (a) is a plan view and FIG.
(b) is a sectional view of the direction of the shearing force acting on the upper and lower surfaces of the metal plate as seen from the rolling direction entry side. However, in FIG. 9 and (b) of FIG. 10 described later, the plate thickness direction is shown in an enlarged manner compared to the plate width direction.

As shown in FIG. 9 (a), there is a deviation of an angle θ between the speed vector in the roll rotation direction and the speed vector in the rolling direction. Relative slip occurs. As a result, a shearing force F ₁ from the end A to the end C acts on the upper surface of the metal plate, and a shearing force F ₂ from the end C to the end A acts on the lower surface of the metal plate. At this time, if the coefficient of friction between the work roll and the metal plate is the same on the upper and lower surfaces of the metal plate and also in the plate width direction of the metal plate, the shearing forces F ₁ and F ₂ in the plate width direction are
It looks like Figure 9 (b). That is, F ₁₁ = F ₁₂ = F ₁₃ ,
F ₂₁ = F ₂₂ = F ₂₃ , and F ₁₁ = F ₂₁ , F ₁₂ =
Since F ₂₂ and F ₁₃ = F ₂₃ , the forces in the plate width direction on the upper and lower surfaces of the metal plate cancel each other out. Therefore, at the ends A and B of the metal plate, only the plastic flow in the plate width direction due to the lack of the restraining force normally occurs.

FIG. 11 shows an example of a roll whose surface roughness is changed in the width direction, and FIG. 10 shows the coefficient of friction between the work roll and the upper and lower surfaces of the metal plate using a roll as shown in FIG. 6 is an example showing a relationship between a metal plate and upper and lower work rolls when roll cross rolling is performed at a cross angle θ by changing the work roll in the axial direction. FIG. 10 (a) is a plan view, and FIG. 10 (b) is a cross-sectional view of the direction of the shearing force acting on the upper and lower surfaces of the metal plate as seen from the rolling direction entry side. In this method, the surface roughness of the upper work roll is increased on the side of the end A and is decreased on the side of the end C, and the surface roughness of the lower work roll is reduced on the side of the end A and increased on the side of the end C. The friction coefficient between the work roll and the metal plate is changed in the axial direction of the work roll by arranging and rolling.

At this time, a shearing force F ₁ from the end A to the end C acts on the upper surface of the metal plate, and a shearing force F ₂ from the end C to the end A acts on the lower surface of the metal plate. To do. However, looking at the sizes of F ₁ and F _{2 in} the width direction of the plate, Fig. 10 (b)
As shown in FIG. ₁₁ , F ₁₁ <F ₁₂ <F ₁₃ , F ₂₁ > F ₂₂ > F ₂₃ , and F ₁₁ <F ₂₁ , F ₁₂ = F ₂₂ , F ₁₃ > F ₂₃ . Therefore, from the relative relationship of the force of the upper and lower surfaces of the plate,
An inward force acts on both the end A and the end C.

In this way, by applying an inward shearing force in the plate width direction at the end of the metal plate, an inward plastic flow in the plate width direction can be generated. That is,
It is possible to cancel the plastic flow of the metal plate caused by rolling.

Next, the reason why the plastic flow can suppress the defective shape of the rolled metal sheet will be described.

The ear wave or the middle stretch is caused by the difference in the stretch in the longitudinal direction in the width direction of the plate. Therefore, if the elongation in the longitudinal direction approaches a uniform state in the plate width direction,
It can reduce or even prevent ear waves or mid-stretch.

The present invention utilizes the inward shearing force in the plate width direction at the end portion of the metal plate produced by the method as described above to promote the elongation in the longitudinal direction at the end portion of the metal plate. Is. In this way, it is possible to roll so that the elongation in the longitudinal direction becomes equal in the plate width direction, and as a result, it is possible to mitigate or further prevent defective shapes.

In the present invention, "a spiral polishing roll is used" in order to apply the inward shearing force in the plate width direction.
The method or “means of changing the friction coefficient between the work roll and the metal plate in the axial direction of the work roll” is adopted. As a method of changing the friction coefficient between the work roll and the metal plate in the roll axial direction, any method such as changing the roll temperature in the axial direction or changing the temperature of the metal plate in the plate width direction is used. However, considering that it does not require the introduction of large-scale new equipment and does not consider the influence of the thermal expansion of the metal plate or roll, its use is indispensable in the cold rolling operation. It is preferable to change at least one of the types, temperature, concentration, viscosity, emulsion particle size and supply amount of the rolling oil, and the surface roughness of the work roll itself in the roll axial direction.

Generally, when the surface roughness of the work roll is constant, the temperature of the rolling oil is raised, the concentration is lowered,
The friction coefficient can be increased by performing at least one of the operations of decreasing the viscosity, decreasing the emulsion particle size, and decreasing the supply amount. Further, if the various conditions of the rolling oil are kept constant, the surface roughness of the work roll may be increased. If this is performed in the roll axis direction of roll cross rolling, plastic flow in the plate width direction occurs at the end portion of the metal plate, so that defective shapes can be prevented.

For example, if rolling oils having different temperatures are used, the friction coefficient between the metal plate and the work rolls also differs. Therefore, when the work rolls are arranged as shown in FIG. If the rolling oil having a temperature higher than that of the C side is supplied to the end A side of the upper surface and the lower surface is rolled under the opposite condition, an inward force acts on the rolled material in the plate width direction, resulting in a defective shape. Can be alleviated.

In the method of the present invention, the material of the metal plate to be rolled,
It is not limited by the material of the work roll or the type of rolling oil. When the friction coefficient is changed in the axial direction, it may be changed gradually, or may be changed regionally so as to have one or more displacement points at the plate central portion or other places.

(B) Rolling with a taper roll
The ability to prevent edge drop will be described.

The taper roll referred to in the present specification is, for example, a roll having a taper (inclination) such that its diameter decreases toward the end of the roll as shown in FIG. This taper is
It may have an arc shape as shown in FIG.

As described above, when a metal plate is rolled by a normal roll, the work roll receives a reaction force from the metal plate and is flatly deformed. However, this amount of deformation sharply decreases in the vicinity of the edge of the plate width, which in turn deforms the metal plate. Therefore, even if the plastic flow in the strip width direction can be prevented by the above method, edge drops still occur in the rolled strip.

When a taper roll is used for rolling, the rolling force at the end of the strip width during rolling is smaller than that at the other parts, but the work roll is deformed, so that a sharp deformation at the end of the strip width occurs. The reduced amount is offset by the taper, resulting in a rectangular roll gap profile. In this way, since the cross-sectional shape of the metal material at the time of rolling can be made rectangular, it is possible to prevent edge drop that occurs when the plate width end portion is deformed by the work roll.

By carrying out the above methods (A) and (B) at the same time, it is possible to manufacture a metal plate free from edge drop and free from shape defects. Therefore,
As a mode of using the taper roll, there is a method of using only one of the upper and lower sides as a taper roll, a method of symmetrically arranging a roll having a taper on only one side, and the like, but in the present invention, all of them are used. Can be applied.

At this time, the taper needs to exist at least in a portion which comes into contact with the end portion of the width of the metal plate to be rolled.
Further, as shown in FIG. 12, when the shearing force in the plate width direction is generated by the spiral polishing roll, this spiral polishing must also exist at least in the part in contact with the plate width end part, but in other parts. There is no particular limitation.

The effects of the present invention will be described below based on examples.

[0043]

Example 1 A metal plate was cold-rolled by using rolls having an arcuate taper having a curvature of 25 mR at the ends as shown in FIG. 13 as upper and lower work rolls. At this time, the upper and lower work rolls were provided with spiral polishing only on the taper portion, and were arranged so that an inward shearing force would work in the backward movement region of the metal material (arrangement in FIG. 5). The surface roughness in the direction perpendicular to the polishing grain in the normal polishing part where there is no taper on the upper and lower work rolls is 0.2 μm in Ra and Ra in the spiral polishing part.
Is 1.0 μm, and the polishing angle (α in FIG. 5) is 45 ° with respect to the roll circumferential direction.

As a rolling oil, the viscosity at 40 ° C. is 40 cSt
Using the above emulsion, a plain steel with a plate thickness of 2.0 mm and a width of 1200 mm is used with a work roll diameter of 550 mm and a backup roll diameter of 15.
It was rolled with a 00Hi 4Hi rolling mill. The rolling reduction was 30% and the rolling speed was 450 m / min.

FIG. 15 shows the plate thickness deviation with reference to the plate central portion.
Figure 16 shows the steepness calculated from the difference in stretch from the center of the plate at a certain position in the plate width direction. The cross-sectional shape of the rolled metal plate in the plate width direction can be seen from FIG. 15, and the planar shape can be seen from FIG. Note that the steepness is calculated by converting the difference in elongation in the rolling direction at each position in the strip width direction and in the central part of the strip, and when the steepness is negative, the elongation is smaller than in the central part of the strip (so-called medium stretch state). The positive steepness means that the elongation is larger than that in the central portion of the plate.

Under the same conditions, rolling was carried out using a work roll having a taper, but with polishing grains parallel to the circumferential direction of the roll (normal polishing). The results are also shown as Δ in FIGS. 15 and 16.

From FIG. 15, it can be seen that when rolled by the method of the present invention, it is possible to obtain a rolled plate having a good cross-sectional shape with no edge drop as much as when rolled by using a conventional taper work roll. . On the other hand, it can be seen from FIG. 16 that the difference in elongation in the strip width direction is small and the steepness is improved.

By the way, the difference in elongation in the strip width direction also influences the tension in the rolling direction, and at a position where the steepness is negative, a larger tensile force acts than at the central portion, and conversely at a position where the steepness is positive. The tensile force of is smaller than that of the central part. With the conventional method of rolling using a taper work roll, the elongation at the plate end cannot be obtained, so a very large tensile stress is generated, which causes plate breakage. According to FIG. 16, it can be seen that the steepness difference of the steel material rolled by the method of the present invention is small and the deviation of such tension is also small.

[0049]

Example 2 Roll cross rolling was carried out under the same rolling conditions as in Example 1. As the work roll, one having the same taper as in Example 1 and having different surface roughness in the axial direction as shown in FIG. 14 (Ra 0.2 μm and Ra 1.0 μm) was used. At this time, it is only the taper portion that has a large surface roughness. The roll cross angle (θ in FIG. 9) was set to 0.6 °, and the arrangement was such that an inward shearing force in the plate width direction worked (arrangement in FIG. 10).

Further, parallel roll rolling (cross angle 0 °) using the same rolls as used in the method of the present invention was carried out for comparison. In both cases, the surface roughness of the roll was the same as that of the example of the present invention.

FIG. 17 shows the plate thickness deviation with reference to the plate central portion,
FIG. 18 shows the steepness calculated from the stretching difference from the central portion of the plate at a certain position in the plate width direction, as in Example 1. From these figures, it can be seen that the steel material rolled by the method of the present invention has a cross-sectional shape as good as that of the steel material rolled by using the conventional taper work roll, and also has an excellent planar shape.

[0052]

According to the method of the present invention, a metal plate with a small edge drop can be manufactured without causing a defective shape. Therefore, since the magnitude of the tension acting in the rolling direction of the metal plate is also made uniform in the plate width direction, cracks and fractures do not occur during rolling.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a work roll and a metal material during rolling. (a) is a diagram showing that the surface of the work roll is deformed and an edge drop occurs at the end of the metal material when rolling using a normal roll, and (b) is a taper roll. It is a figure at the time of rolling.

FIG. 2 is a diagram illustrating an example of a taper roll.

FIG. 3 is a diagram showing a conventional method of rolling by combining taper rolls.

FIG. 4 is a plan view when a roll is bent in a horizontal direction and rolled, and an arrow indicates a direction of a rotation vector of the roll.

FIG. 5 is a diagram showing a relationship between a rolled material and upper and lower work rolls when rolled using a spiral polishing roll. (a) is a cross-sectional view seen from the exit side, and (b) is a plan view seen from above. In the figure, F ₁ and F ₂ represent shearing forces in the plate width direction.

FIG. 6 is an example of a combination of work rolls in which both ends of the barrel (including a portion in contact with the plate width end) are spirally polished.

FIG. 7 is an example of rolling by changing the polishing state of the upper and lower work rolls.

FIG. 8 is a diagram showing a relationship between a roll and a metal material during rolling.

FIG. 9 shows a relationship between a rolled material and upper and lower work rolls in roll cloth rolling. (a) is a plan view seen from the upper side, and (b) is a sectional view of the rolled material seen from the entrance side. F ₁ and F ₂ in the figure represent shearing forces in the plate width direction.

FIG. 10 shows an example in which roll cross rolling is performed by changing the friction coefficient in the axial direction, and shows the relationship between the rolled material and the upper and lower work rolls. (a) is a plan view showing a state in which rolls whose surface roughness is changed in the axial direction are arranged upside down and roll cross rolling is performed, and (b) is a cross-sectional view of the rolled material as seen from the entrance side. is there.

FIG. 11 shows an example of a work roll whose surface roughness is changed in the width direction.

FIG. 12 is a view showing an example of a taper roll having spiral-shaped polishing eyes.

FIG. 13 is a diagram showing a taper of a work roll used in Example 1.

FIG. 14 is a diagram showing a taper of a work roll used in Example 2.

FIG. 15 is a diagram showing a plate thickness deviation in a plate width direction with respect to a plate central portion.

FIG. 16 is a diagram showing steepness calculated from the difference in stretching with respect to the plate central portion at a certain position in the plate width direction.

FIG. 17 is a diagram showing a plate thickness deviation in a plate width direction with reference to a plate central portion.

FIG. 18 is a diagram showing steepness calculated from the difference in stretching with respect to the central portion of the plate at a certain position in the plate width direction.

[Explanation of symbols]

1. Upper work roll, 2. Lower work roll, 3.
Metal plate.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B21B 37/00 118 8315-4E (72) Inventor Masahiro Matsuura 4-53 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture No. Sumitomo Metal Industries, Ltd. (72) Inventor Kanji Hayashi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Tetsuo Kajiwara, Kannon Shin-machi, Nishi-ku, Hiroshima City, Hiroshima Prefecture 6-22 22 Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (72) Inventor Kazuo Morimoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute

Claims (2)

[Claims] 1. A metal plate is rolled by using a work roll having a spiral-shaped abrasive grain and a taper at a portion in contact with a plate width end of a rolled material, and the metal plate is rolled inward in the plate width direction in a backward movement region of the rolling. A method for producing a metal plate having a small edge drop, which comprises applying the shearing force of 2. A work roll having a taper at a portion which comes into contact with a strip width end portion of a rolled material is used, and a friction coefficient between the work roll and the metal plate is changed in an axial direction of the work roll. A method for producing a metal plate having a small edge drop, which comprises performing roll cross rolling and applying a shearing force inward in the plate width direction to perform rolling.