JPH07265912A - Roll for rolling, grinding method therefor and metal sheet rolling method - Google Patents

Abstract

PURPOSE:To provide a roll used for improved surface gloss of a metal sheet, a grinding method therefor and a rolling method using the roll. CONSTITUTION:A roll has grind mark skewed to the peripheral direction of a roll 1, the skew angle is >=20 deg., further, the roughness of larger one out of an average roughness of the axial direction or peripheral direction of roll is 0.1-0.5mum. The roll 1 is produced by the grinding method that the rotating axis 4 of a disk grinding stone 3 having a radius (r) rotating in a speed VT is offset by X in right angle to the roll axis, while a part of the periphery of grinding face of grinding stone is brought into contact with the roll surface and is traversed relatively in the axial direction of roll, the roll is rotated at a speed VF and a skew angle theta is >=20 deg.. The angle theta is calculated from VT, (r), X, VF. This roll is used for cold rolling as a large diameter work roll of tandem mill, etc., a metal sheet of high gloss is produced in high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll for rolling a metal plate having abrasive grains inclined with respect to the circumferential direction of the roll and a method for polishing the surface of the roll for producing such a roll.
The present invention also relates to a rolling method for producing a glossy metal plate using such a roll.

[0002]

2. Description of the Related Art In the rolling of a metal plate, since the surface irregularities of a work roll (hereinafter simply referred to as "roll") are transferred to the metal plate, the surface of the roll depends on the surface roughness required for the product metal plate. The surface is polished. For example, for rolling cold-rolled steel sheets and the like that require excellent luster, rolls with a small surface roughness that are ground with a high count grindstone are used. However, the smaller the roll surface roughness is, the longer the polishing work of the roll surface is, resulting in an increase in the cost of manufacturing and repairing (re-polishing) the roll, and eventually in the manufacturing cost of the metal plate.

Conventionally, cold rolling of thin steel sheets, especially stainless steel sheets, has been carried out by a Sendzimir mill using a work roll having a small diameter of 100 mmφ or less, but recently, in the case of a product whose surface quality is not so severe, for example, 180 φmm or more. Rolling with a tandem mill or a revers mill, which is a rolling mill for ordinary steel using a diameter roll, has come to be performed.
This is because the work roll has a large roll diameter and a water-soluble emulsion having a large cooling capacity is used as the rolling oil, which enables high-speed rolling and high productivity can be expected. However, the thin steel sheet rolled by the rolling mill for plain steel has a lower surface gloss than the thin steel sheet obtained by Sendzimir mill rolling. This is because when high-speed rolling is performed with the large-diameter work roll as described above, an oil film is formed between the work roll and the steel plate, and the steel plate partially becomes concave (oil pit) due to hydraulic pressure.

From the idea of preventing the deterioration of gloss due to the oil pits described above, Japanese Patent Laid-Open No. 227904/1985 discloses that the direction of the grinds on the surface of the rolled material and the direction of the grinds on the surface of the work roll are crossed. A method of rolling by rolling is disclosed.
In this method, the effect that the oil pits are reduced by dividing the surface grinding of the metal plate before rolling,
The inclination angle (θ described later) of the rolls used there is at most 10 °. Further, as a method of manufacturing a roll, only a method of feeding the grinding wheel in parallel to the roll axis and faster than usual is described, and it is extremely difficult to set θ to 20 ° or more. .

[0005]

SUMMARY OF THE INVENTION The present invention aims to produce a metal sheet having an excellent gloss which cannot be obtained by rolling using a conventional roll by improving the surface condition of the rolling roll, and in particular, The challenge is to develop a cold rolling technology that can produce highly efficient metal sheets, especially stainless steel sheets, with excellent luster comparable to that of products rolled at low speed by Sendzimir mill, even with high-speed rolling mills with high productivity. It was made as.

[0006] A specific object of the present invention is to roll a metal plate having an appropriate surface shape (how to grind and roughness), and a polishing method for obtaining such surface shape.
Another object of the present invention is to provide a method for producing a metal plate having high gloss using this roll.

[0007]

Means for Solving the Problems In the course of research on a roll for rolling a metal plate, the inventors of the present invention polished the roll surface (fine polishing streaks imparted to the surface during roll polishing).
It was found that the direction of has a great influence on the properties of the metal plate after rolling. That is, in ordinary polishing, since the grindstone is pressed against the roll surface while rotating the roll, the polishing stitches are aligned in a direction substantially perpendicular to the axial direction of the roll (roll circumferential direction). However, rolling with a roll having its polishing grain inclined with respect to the circumferential direction of the roll (hereinafter referred to as a tilted polishing roll) has a larger surface glossiness than rolling with a normal roll having the same surface roughness. It will improve.

The gist of the present invention resides in the following (1) to (3).

(1) The surface has abrasive grains having an inclination of 20 ° or more with respect to the roll circumferential direction, and the larger one of the centerline average roughness (Ra) in the roll axial direction or the circumferential direction. Is 0.1 ~
Roll for rolling metal plate with 0.5 μm.

(2) After arranging the rotation axis of a disk-shaped grindstone having a radius r (mm) so as to match the normal line of the roll, tilt the rotation axis of the grindstone in the roll axis direction to bring one end of the grindstone into contact with the roll surface. Or, as it is, the rotation axis of the grindstone is displaced from the normal line of the roll to bring one end of the grindstone into contact with the roll surface, and between this contact point and the rotation axis of the grindstone, X is applied in the direction perpendicular to the roll axis.
(Mm) is a method of polishing the surface of the roll by rotating the roll while moving the grindstone in that state while relatively moving in the axial direction of the roll, and the angle defined by the following formula The surface polishing method of the rolling roll according to claim 1 or 2, wherein θ is set to 20 ° or more.

[0011]

[Equation 2]

Where V _T is the rotational speed of the grindstone (m / min)
, V _F is the relative movement speed of the grindstone in the roll axis direction (m / min)
, V _R is the rotation speed of the roll (m / min), α = sin
^-1 (X / r).

(3) A method for rolling a metal sheet having excellent gloss, characterized in that the roll of (1) above is used as a work roll for cold rolling.

FIG. 1 is a partially enlarged view of the roll surface showing the concept of the inclined polishing roll of the present invention. As shown in the figure, the roll 1 of the present invention has abrasive grains 6 inclined with respect to the roll circumferential direction. Although the polishing stitches 6 are actually extremely fine and intermittent streaks, they are exaggerated in the drawing. When the angle of inclination of this polishing grain is θ, θ ≧ 20 ° must be satisfied. The direction of this inclination may be either left or right. Here, for convenience, the clockwise direction shown in the drawing is +, and the opposite direction is −, but the above 20 ° or more means an absolute value of 20 ° or more. And the roughness of the roll surface is
The larger centerline average roughness (Ra) in the roll axial direction or roll circumferential direction shown in Fig. 1 must be in the range of 0.1 to 0.5 µm.

2A and 2B are views for explaining the roll polishing method of the present invention and the definitions of the symbols in the above formulas. FIG. 2A is a side view showing the positional relationship between the roll and the grindstone, and FIG. 2B is a plan view.
(C) is an enlarged view of the vector of (b), and (d) is a view showing one mode of bringing the end of the grindstone into contact with the roll surface.

First, in FIG. 1A, 1 is a roll, 2 is its axis (rotation axis), 3 is a grindstone, 4 is its rotation axis, and 5 is a normal line of the roll.

FIG. 2B is a plan view seen from the direction in which the grindstone is applied (in this case, from above). In the polishing method of the present invention, first, the rotating shaft 4 of the disk-shaped (including cup-shaped) grindstone 3 having a radius r (mm) is arranged so as to coincide with the normal line 5 of the roll. Next, the grindstone rotating shaft 4 is tilted with respect to the normal line 5. This inclination angle is ψ. Note that ψ may be 0 in a special state as shown in FIG. By doing so, a part (hereinafter, referred to as an end) of the peripheral portion of the grinding surface of the grindstone is brought into contact with the roll surface. Let the contact point be P.

With the edge of the grindstone and the roll surface kept in contact with each other as described above, the grindstone rotating shaft 4 is set by shifting it from the roll shaft 2 at a right angle by X (mm). This X is called an offset amount. Further, as shown in (a), the grindstone and the roll are rotated in this state, and the grindstone and the roll are relatively moved in the direction of the roll shaft 2. Relative movement means that the roll is rotated at a fixed position and the rotating grindstone is fed in the roll axial direction, or the grindstone is rotated at a fixed position and the rotating roll is fed in the axial direction. Or, it means changing the relative position by changing the moving direction or speed of both.

An enlarged view of the vector at the contact point shown in FIG. 7B is shown in FIG. Rotation speed V _{T of} the grindstone, relative movement speed V _{F of} the grindstone in the roll axial direction, and rotation speed V of the roll
The vector of _R is shown. In the figure, α is sin ⁻¹ (X / r), and from these relationships, the inclination angle θ of the polishing eye is −1 below.
It is clear that it is calculated by the formula.

[0020]

[Equation 3]

When the inclination direction of the grindstone is reversed in FIG. 2 (a), the inclination angle θ is calculated by the following equation-2.

[0022]

[Equation 4]

If the roll rotation direction is opposite, -1
Positive and negative V _R of formula and the minus equation is reversed. The radius and offset amount of the grindstone used in the present invention are not particularly limited, but it is desirable that the grindstone radius r is 30 to 300 mm and the offset amount X is 20% or more of the grindstone radius in view of polishing efficiency.

FIG. 2D shows that the rotary shaft 4 of the grindstone is not tilted,
The state is parallel to the normal line 5 (ψ = 0) and is displaced from the normal line 5 in a direction perpendicular to the roll axis. in this case,
The distance from the contact point between the end of the grindstone and the roll surface to the grindstone rotation axis, that is, the offset amount X is equal to the radius r of the grindstone. The vector at the contact point between the grindstone end and the roll surface is the same as in (c). That is, the polishing method of the present invention can be carried out even in such a state.

[0025]

The operation and effect of the present invention will be described below with reference to the rolling method for producing a metal plate having a high gloss using the inclined polishing roll of the present invention.

FIG. 3 is a diagram schematically showing the relationship between rolls and rolled material during rolling. Rolled material S has plate thickness t ₁ to t ₂
When the rolling speed of the rolled material on the roll-in side (point A) is v ₁ and that on the exit side (point B) is v ₂ when rolling to V, naturally v ₁ <v ₂ . The point where the speed v of the rolled material becomes the same as the peripheral speed V of the roll (point N) is called the neutral point, and from this point the front (roll-out side) is called the advanced zone and the rear (roll-in side) is called the reverse zone. .

FIG. 4A is a plan view conceptually showing the rolling of a metal plate using a normal roll, and FIG. 4B is a pattern (hereinafter referred to as a transfer pattern) formed on the surface of the metal plate by this rolling. It is an explanatory diagram of). Focusing now on one point of the convex portion on the roll surface, the locus on the surface of the rolled material S at this point has a speed difference between the advanced region and the reverse region as described above, and → N → B. That is, not only the convex portion of the roll is transferred to the surface of the rolled material, but also a pattern is formed by the sloping in the A → N → B direction on the surface of the roll and the surface of the rolled material. This rolling direction is the same as the roll rotating direction. Therefore, a transfer pattern (unevenness) is formed on the surface of the rolled material by being emphasized by the number of polishing stitches of the roll or more than the length of the polishing stitches.

FIG. 5A is a plan view conceptually showing rolling using the inclined polishing roll of the present invention, and FIG. 5B is an explanatory view of a pattern formed on the metal plate surface by this rolling. is there. Also in this case, the roll-polished grain is A →
Although it moves like N → B, since the direction of the polishing eyes is different from the roll rotation direction (having an angle of θ), the polishing eyes are in a state of sliding sideways. Due to this snag, some adjacent transfer patterns will be scraped or crushed. That is, the shaded area in (b) is smoothed. When the roll polishing grain is inclined, the grinding grain transferred and remaining is near the exit side, and the polishing grain transferred on the entrance side almost disappears due to the above grinding or crushing action.

As shown in FIG. 4, the surface of the metal plate (rolled material) S after being rolled by a normal roll having the surface polishing marks parallel to the roll circumferential direction has the polishing marks ( (Rolled skin) is transferred, resulting in more emphasized streaky irregularities. Therefore, unless the roughness of the roll-polished mesh is made extremely small, the gloss of the rolled material is reduced. On the other hand, when the roughness of the roll surface is so small that the transfer of the roll surface is not conspicuous, slippage occurs between the rolled material and the roll because the directionality of the roughness and the rotation direction of the roll match. Further, at high speed rolling, oil pits are generated and the gloss of the rolled material is further reduced.

In the case of rolling using the inclined polishing rolls shown in FIG. 5, the roll surface transferred to the rolled material S is smoothed by the above-mentioned crushing or grinding action and becomes extremely glossy. This effect and the above-mentioned
The surface gloss of the metal plate after rolling is remarkably improved by the reduction of oil pits due to the division of the polishing streaks in the metal plate before rolling as described in JP-A-60-227904.

FIG. 6 shows the above-mentioned movement (smoothness) in the rolling direction until one polishing eye hits an adjacent polishing eye when the distance b between the polishing eyes is 1 in the rolling method of the present invention shown in FIG. FIG. 6 is a diagram showing the relationship between the distance (L) and the inclination angle θ of the polishing eye. The larger θ becomes, the shorter the length L in the slipping direction becomes, and the number of the ground transfer marks to be crushed increases.

As is clear from FIG. 6, when θ is less than 20 °, L is long and the crushing effect is small.

It is for this reason that the inclination angle θ of the polishing eye is set to 20 ° or more in the present invention. The larger θ is, the greater the above effect is. The preferred range of θ is 45 ° or more,
Most preferable is 60 ° or more.

As is clear from the above description, rolling with an inclined polishing roll gives a metal plate having a higher gloss than when rolled with a roll having the same surface roughness and a roll for normal polishing.

In other words, if the inclined polishing roll is used for producing the metal plate having the same glossiness, the surface may be rough, and the time and man-hour for polishing the roll can be reduced.

Next, the roughness of the roll surface will be described.

When the inclined polishing roll of the present invention is used particularly for improving the surface glossiness of a metal plate, the larger one of the centerline average roughness (Ra) in the axial direction or the circumferential direction of the roll is selected.
It is desirable to set it in the range of 0.1 to 0.5 μm. The improvement of the gloss of the surface of the rolled material by inclining the roll polishing grain is the effect of grinding or crushing by the polishing grain as described above. Therefore, the size of the grind is required to some extent.

FIG. 7 is an enlarged view showing cross sections of the roll surface and the rolled material surface. When the roll surface roughness is extremely small as shown in (a), slip is likely to occur in high speed rolling.

Further, an oil film of lubricating oil is formed between the roll surface and the surface of the rolled material, and the oil pressure causes the rolled material to be pressed to form pits (oil pits). descend. On the other hand, when the roll surface roughness is large as shown in (c), seizure occurs due to direct contact between the roll convex portion and the rolled material convex portion. In addition, the metal powder generated by abrasion of the convex portions of the roll and scraping of the rolled material scratches the surface of the rolled material, which causes a decrease in glossiness.

As shown in FIG. 7B, if the surface roughness of the roll is appropriate, no oil pits are generated and no seizure occurs.
The smoothness due to the sloping of the polishing eyes significantly improves the glossiness of the rolled material. Incidentally, the measurement of the surface roughness is performed by setting the direction, but in the case of the inclined polishing roll of the present invention, it is either the roll circumferential direction or the axial direction that mainly affects the action and effect described so far. Is the rough direction. Therefore, in this case, the surface roughness Ra is adjusted to be in the range of 0.1 to 0.5 μm in either the axial direction or the circumferential direction, whichever is larger.
Such roughness adjustment can be easily performed by selecting the roughness of the grindstone used in the polishing operation.

The present invention will be described in more detail below with reference to examples.

[0042]

[Embodiment 1] A roll grinder equipped with a mechanism capable of changing the rotation direction and rotation speed of a roll as a work material and changing the mounting position and angle of a rotary shaft of a disk-shaped rotary grindstone. It was used.

The roll has a diameter of 100 mm, a body length of 450 mm, and an overall length.
850mm work roll for 4Hi rolling mill (material SUJ-2, hardness H
s ≧ 95) under various polishing conditions, and then use it as the upper and lower work rolls, using SUS 430 steel with a thickness of 2.5 mm and a width of 50 mm for hot rolling and annealing (pickled) as the test material. Levers rolling was performed and the surface roughness after rolling was measured.

Table 1 shows the polishing conditions, the surface roughness after polishing (rougher in the axial direction or the circumferential direction), and the inclination angle θ of the polishing mesh. Table 2 shows the rolling pass schedule. In addition,
The rolling speed was 20 m / min, and the rolling oil was 90 cSt mineral oil based rolling oil used neat (as undiluted solution). Table 1 also shows the surface gloss (incident angle 20 °) after 5-pass rolling.

In Examples 1 to 6, the grindstone was tilted with respect to the normal line of the roll axis, and ψ in FIG. 2A was set to −2 ° or + 2 °.
Moreover, the roll was mounted offset from the roll axis, and was rolled by a roll that was polished so that the polishing marks on the roll surface were inclined at 35 to 70 °.

Comparative Example 1 is an example in which the roll roughness is reduced by the conventional polishing method, and 2 and 3 are examples in which the roll roughness is out of the range of the present invention, although the polishing method of the present invention is used for polishing. .

Looking at the glossiness after rolling shown in Table 1 together,
It can be seen that the surface gloss after rolling is significantly high when the inclined polishing roll of the present invention is used. The larger the inclination angle θ of the polishing eye, the greater the degree of improvement in gloss. On the other hand, in Comparative Example 1, since the surface roughness of the roll is small, not the slant polishing, slip occurs during rolling and the glossiness is low. In Comparative Example 2, the inclination angle θ of the grind is appropriate, but the roll surface roughness is too small to improve the glossiness. On the contrary, in Comparative Example 3, the roll surface was too rough and the glossiness was poor, and seizure occurred during rolling.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Example 2] Roll diameter 380 mm, body length 1450 mm, total length 3400 mm
4Hi tandem mill # 5 work roll for stand (material 5% Cr forged steel, hardness Hs ≧ 97) was polished under the conditions shown in Table 3.

Rolled, SUS 430 steel, thickness 2.5mm, width 1000
The hot rolling-annealing material (pickled) of mm was performed according to the pass schedule of Table 4.

As the work rolls of the # 1 to # 4 stands, rolls polished by the conventional method shown in Comparative Example 5 of Table 3 were used, and the work rolls above and below the # 5 stand were subjected to various polishing methods shown in Table 3. The roll was polished by. The surface gloss after rolling is also shown in Table 3.

Comparative Example 4 is rolling by means of rolls polished by the conventional method. There is almost no angle of grind on the roll surface (θ = 0 °). On the other hand, in the example of the present invention, the grindstone is tilted with respect to the normal line of the roll axis (ψ = −2 ° to + 2 °) and offset with respect to the roll axis (X = 20 to 99 mm), so that the polishing surface of the roll surface is polished. Was changed from 21 ° to about 90 °.
As described above, the gloss after rolling is dramatically improved by using the roll having the inclined polishing grain. However,
When the inclination of the grind is too small as 10 ° as in Comparative Example 5, the effect of improving gloss is small.

The inclination angle θ of the polishing eye is the roll rotation speed V _R
Although it is also affected by the grindstone rotation speed V _T , it is clear from the examples that the greatest effect is the offset amount of the grindstone, and it is necessary to make the offset amount as large as possible.

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

The inclined polishing roll of the present invention exerts a remarkable effect in improving the surface gloss of a product when rolling a metal plate. By using this roll, the occurrence of oil pits, slip flaws, and the like is reduced even when high-speed rolling is performed with a work roll having a large diameter in a tandem mill or a revers mill, and a thin metal plate having excellent glossiness can be manufactured. In particular, the practical benefit of being able to roll stainless steel sheets requiring extremely high glossiness with high efficiency is great.

In the polishing method of the present invention, it is easy to make the angle of the polishing stitches given to the roll inclined by 20 ° or more with respect to the circumferential direction. By making a slanted polishing grain in this way, a metal plate having high gloss can be produced without extremely reducing the roughness of the roll surface, so that the roll polishing work time can be shortened and the polishing condition management and Whetstone management becomes easy.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a surface of an inclined polishing roll of the present invention.

FIG. 2 is a diagram illustrating a roll polishing method of the present invention,
(A) is a side view showing the positional relationship between the roll and the grindstone, (b)
Is also a plan view, (c) is an enlarged view of the vector of (b),
(D) is a figure which looked at an example of the set state of a roll and a whetstone from the roll axis direction.

FIG. 3 is a diagram showing a relationship between rolls and rolled material during rolling.

4A and 4B are diagrams illustrating rolling of a metal plate by a conventional roll, FIG. 4A is a plan view, and FIG. 4B is a schematic diagram illustrating formation of a transfer pattern on the surface of the metal plate.

5A and 5B are diagrams illustrating rolling of a metal plate by an inclined polishing roll of the present invention, FIG. 5A is a plan view, and FIG. 5B is a schematic diagram illustrating a state of forming and smoothing a transfer pattern on the surface of the metal plate. is there.

FIG. 6 is a diagram showing a relationship between an inclination angle (θ) of a polishing eye and a minimum slip length (L) for a transfer flaw of the polishing eye to be crushed and smoothed by an adjacent polishing eye.

FIG. 7 is an enlarged cross-sectional view showing a contact state between a roll surface and a rolled material surface during rolling. (A) shows a case where the roll roughness is too small, (c) shows a large case, and (b) shows an appropriate case. Is.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B24B 5/37 (72) Inventor Ken Masui 4-53-3 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd. (72) Inventor Yukihiko Matsudaira 2-12-1, Minatomachi, Joetsu City, Niigata Prefecture Japan Stainless Steel Co., Ltd. Naoetsu Works

Claims (3)

[Claims] 1. The surface has abrasive grains having an inclination of 20 ° or more with respect to the roll circumferential direction, and the larger one of the centerline average roughness (Ra) in the roll axial direction or the circumferential direction is larger. 0.1 to 0.5
Roll for rolling a metal plate that is μm. 2. A rotation axis of a post-grinding stone is tilted after the rotation axis of a disk-shaped grindstone having a radius r (mm) is aligned with the normal line of the roll.
Or, without tilting, shift one end of the grindstone as it is from the normal line and bring one end of the grindstone into contact with the roll surface, and provide a distance of X (mm) between this contact point and the rotation axis of the grindstone in the direction perpendicular to the roll axis,
A method of polishing the roll surface by rotating the roll while relatively moving in the axial direction of the roll while rotating the grindstone in that state, the angle θ defined by the following formula 20 °
The method for polishing the surface of a rolling roll according to claim 1 or 2, wherein the above is performed. [Equation 1] Where V _T is the rotational speed of the grindstone (m / min), V _F is the relative movement speed of the grindstone in the roll axis direction V _F (m / min)
, V _R is the rotational speed of the roll (m / min), α = sin ⁻¹ (X / r). 3. A method for rolling a metal sheet having excellent gloss, which comprises using the roll according to claim 1 as a work roll for cold rolling.