JPH0413403A - Dull roll and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a rolled plate excellent in distinctness of image and press form ability by providing transferring projection parts implanted with uniformly dispersed diamond particles on the outer peripheral surface of a roll body part. CONSTITUTION:The transferring projection parts implanted with uniformly dispersed diamond particles are provided on the outer peripheral surface of the roll body part. Patterns having inverted conical recessed parts and annular projecting parts round them are arranged at random in the rolling direction and in the direction at right angles to it on the surface of a rolled metallic plate and roughness free from anisotropy is transferred in the plate surface. The center Ra of the surface and the waviness Wca of the central line of a wave are controlled and the surface roughness satisfying both distinctness of image and press form ability can be transferred and given. Further, since the transferring projection part is composed of super hard diamond particles and extremely excellent in wear resistance, stable surface roughness can be given with high reproductivity to a metallic pate to be rolled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dull roll and a method for manufacturing the same. The present invention relates to a dull roll used for rolling to obtain a rolled plate having a hardness and a manufacturing method thereof.

[Conventional technology]

Surface properties are an important quality required for rolled metal sheets. Its surface properties include beauty, adhesion to paint and enamel, press workability, corrosion resistance, and gloss, but the surface roughness of the metal plate has an important effect on these properties. .

In recent years, the paint finish quality of vehicle bodies, especially private cars, has increased (
Appearance) is an important quality control item, and there are various evaluation items for painted surfaces, but among them, the painted surface has little diffused reflection, has excellent gloss, and has good image mapping. There is a strong demand for excellent image clarity with little distortion, that is, excellent image clarity.

The sharpness of the painted surface is influenced by the type of paint and the painting method, but it is known to be strongly influenced by the surface roughness of the metal plate as the base for painting.

This is because if the surface of the metal plate used as the base for painting has a small proportion of the horizontal surface area and is highly uneven, the surface of the metal plate to be painted will also have a small proportion of the horizontal surface area and will be uneven. This is because the surface area becomes larger, and as a result, light is diffusely reflected on the painted surface, which impairs glossiness, and also causes image distortion and deteriorates image clarity. In general, the surface roughness of a metal plate is expressed by the centerline average roughness Ra and the filtered centerline waviness Wca. Deteriorates image quality.

On the other hand, metal plates used for vehicle bodies, etc., are required to have good press workability in addition to the above-mentioned image clarity. Except in the case of extrusion molding, the pressure forming process involves movement of the material, so the metal plate slides in contact with the tool during pressure forming, and the so-called surface roughness of the metal plate is caused by the movement of the material. °“Deformation”°defects occur.And,
It is known that in order to prevent this "deformation", it is necessary to have a center line average roughness Ra of a certain value or more.

Furthermore, if the surface roughness of the metal plate has in-plane directionality, the amount of material flowing into the mold during pressure forming will differ depending on the direction, leading to wrinkles and breakage. It deteriorates its press workability.

As described above, the surface roughness of a metal plate has a large effect on its image clarity and press workability, and therefore various efforts and considerations have been made to control the surface roughness. As a method of imparting surface roughness suitable for each purpose to a metal plate, as is well known, a cold rolling roll or a dull roll whose surface has been processed to a predetermined roughness is used as a rolling roll. The most commonly used method is to roll a metal plate under a predetermined pressure to transfer the roughness of the dull roll surface to the surface of the metal plate, thereby imparting desired roughness to the surface of the metal plate. Further, as methods for dulling the roll surface of these dull rolls, shot blasting, electrical discharge machining, laser dulling, etc. are widely used.

[Problem to be solved by the invention]

However, the shot blasting method is very easy to apply, and the roll surface is work-hardened by the process.
Although it has advantages such as improving the abrasion resistance of the roll, it is difficult to uniformly control the roughness imparted to the roll surface, and the surface roughness of the obtained roll is likely to be uneven.
There are problems in that it takes a long processing time to roughen the surface of a hard roll, and it is difficult to obtain deep roughness.

Furthermore, in the electric discharge machining method, the roughness imparted to the roll surface is controlled by changing the voltage and frequency applied between the rotating roll and the electrode moving in the axial direction. The range of the discharge arc that determines the roughness is determined by the shape of the electrode, so it is difficult to obtain fine roughness with a small pitch beyond a certain limit. In addition, since it is difficult to maintain high mechanical strength of the convex portions formed while being affected by heat by electric discharge machining, the initial wear of the resulting roll during rolling is severe, and the surface roughness of the roll is transferred. There is a problem in that the surface roughness of the metal plate tends to vary greatly during rolling.

In this way, when a metal plate is rolled using a roll that has been dulled using the Sigitplast method or electric discharge machining method, the metal plate is composed of irregular peaks and valleys, and the horizontal surface portions are It has a surface with very little roughness. Therefore, there is no problem in transferring the minimum surface roughness required for press working to the metal plate, but if the surface of these metal plates is painted, Since a coating film is formed, the image clarity is poor.

On the other hand, in the laser dull processing method, the roughness imparted to the roll surface is controlled by changing the circumferential speed of the rotating roll and the irradiation conditions such as the moving speed and laser output of the laser irradiation head that moves in the axial direction. By doing this, on the roll surface,
It is possible to form a pattern in which a pattern having a truncated cone-shaped convex part and an annular concave part around it is arranged relatively regularly and has the surface roughness of a horizontal surface portion. Therefore, by using a hole that has been dulled by this method, it is possible to obtain a metal plate that is imparted with an appropriate surface roughness and satisfies press workability and image clarity.

However, according to the laser dull processing method, although it is possible to form unevenness in a very regular arrangement in the rotational direction of the roll, it has the disadvantage that it can only be formed in a relatively irregular arrangement in the axial direction. are doing. As a result, the metal plate rolled by the dull roll obtained by this processing method has anisotropic surface roughness in the plane, and as shown in the graph in Figure 4, the surface roughness is anisotropic in the rolling direction and in the direction perpendicular to the rolling direction. The surfaces have different coefficients of friction. In addition, the fourth
The figure is a graph illustrating the results of measuring the coefficient of friction in the rolling direction and in the direction perpendicular to the rolling direction under different surface pressures for two types of steel sheets A and B rolled with dull rolls using the laser dull processing method.

For this reason, when press forming these metal plates, a phenomenon occurs in which material in a certain direction flows better into the mold, while material in a direction perpendicular to that direction has difficulty flowing in, making the molded product more likely to wrinkle or break. Therefore, a problem arises in that, for example, some kind of countermeasure in terms of press technology is forced to be taken, which increases costs, such as providing a drawing repeat in the mold.

In view of the above-mentioned problems of the prior art, the present invention provides a dull roll and a metal plate capable of improving image clarity and press workability, and imparting surface roughness with no in-plane anisotropy to the surface of a metal plate to be rolled. The purpose of this invention is to provide a method for producing the same.

[Means to solve the problem]

In order to achieve the above object, the present invention has the following configuration. That is, the dull roll according to the present invention has a transfer convex portion formed by evenly dispersing and planting diamond particles on the outer circumferential surface of the roll body.

Further, one of the methods for producing a dull roll according to the present invention is to apply a dispersant in which diamond powder is dispersed and mixed to a mixed powder of Ni powder and/or Cr powder and carbon as a sintering aid to the outer circumference of the sleeve material. Apply it evenly on the surface, and
A thin plate made of an acid-soluble metal coated with a release agent on one side is laminated and covered with the release agent coated side inside and fixed on the outer peripheral surface, and then this is heated to a high temperature. At the same time, pressure is applied from both the inside and outside sides to press and sinter the diamond powder onto the outer peripheral surface of the sleeve material, and then the thin plate at the outermost periphery is peeled off and removed, and the sleeve material is pickled. Diamond powder is exposed on the outer peripheral surface of the sleeve material, and then the sleeve material is fitted and fixed to the core roll as a roll body.

The other method is to apply a dispersant, which is made by dispersing and mixing diamond powder to a mixed powder of Ni powder and/or Cr powder and carbon as a sintering aid, evenly on one side of each of two steel plates. The two tW plates are stacked and fixed with the dispersant-coated surfaces facing each other, and a thin insert plate made of an acid-soluble metal coated with a peeling agent on both sides is arranged between them, Next, this material is heated to a high temperature and pressure is applied from both outer surfaces to press and sinter diamond powder onto one side of each of the two steel plates, and then the insert plate placed in the middle is peeled off and removed. At the same time, two steel plates are pickled to expose diamond powder on one side of the steel plates, and then these steel plates are formed into a cylinder with the side with the diamond powder exposed on the outside. A cylinder is used as the roll body and is fitted and fixed to the roll core shaft.

[Effect]

The dull roll according to the present invention has a transfer projection formed by evenly dispersing and implanting diamond particles on the outer circumferential surface of the roll body, so that the surface of the metal plate to be rolled has four inverted conical parts. A pattern with annular protrusions around it is arranged randomly in the rolling direction and the direction perpendicular to the rolling direction, and transfers the roughness without anisotropy into the plate surface, that is, the center line average roughness Ra of the surface , it is possible to control the filter center line waviness Wca and transfer and impart a surface roughness that satisfies both image clarity and excellent press workability. In addition, the transfer convex portions are made of ultra-hard diamond particles and have extremely high wear resistance, so that stable surface roughness can be imparted to the metal plate being rolled with high reproducibility.

Furthermore, in the method for manufacturing a dull roll according to the present invention,
A dispersant made by dispersing and mixing diamond powder in a mixed powder of Ni powder and/or Cr powder and carbon as a sintering aid is evenly applied on the outer peripheral surface of the sleeve material or steel plate, and then A thin plate is laminated and covered on top and fixed, and these are heated to high temperature and pressed and sintered by applying pressure from both sides, so diamond powder is evenly distributed on the outer surface of the sleeve material or steel plate. This allows for strong sintering. In addition, after this pressing and sintering, the laminated and coated thin plates are peeled off and removed, and the sleeve material or steel plate is pickled, so the diamond powder is exposed on the outer surface of the sleeve material or copper plate. be able to. Here, since the thin plate is made of acid-soluble metal coated with a release agent on the laminated side surface, it is easy to peel off after pressing and sintering, and even if it peels off and remains on the surface, it is easily removed during the subsequent pickling treatment. Can be pickled and removed.

One of the dull roll manufacturing methods according to the present invention involves fitting and fixing the sleeve material obtained as described above to the core roll as the roll body, so that the sleeve material is evenly distributed on the outer peripheral surface of the roll body. A dull roll having a protruding transfer convex portion made of diamond powder can be obtained.

Another method is to form the steel plate obtained as described above into a cylinder with the surface with the diamond powder exposed on the outside, and to fit and fix the cylinder to the roll core shaft as the roll body. Therefore, it is possible to obtain a dull roll having transfer protrusions made of diamond powder that are evenly distributed and protrude on the outer peripheral surface of the roll body. In addition, two control plates are stacked and fixed with the dispersant-coated surfaces facing each other, and a thin insert plate made of acid-soluble metal coated with a release agent on both sides is placed between them, and these are heated to high temperatures. Since pressing and sintering is performed by heating and applying pressure from both outer surfaces, the pressing and sintering can be performed reliably and easily.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1a to 1d are conceptual diagrams illustrating the manufacturing process of the dull roll of this embodiment.

First, a dispersant was prepared by dispersing and mixing 14% by volume of diamond particles with an average particle size of 15 μm in a mixed powder of pure Ni powder mixed with 0.5% by weight of carbon.

and a mold release agent A made of alumina or the like.

Thickness 5 with chemical components equivalent to JIS, SK7
Spread the above dispersant evenly on a 0 mm steel plate (1), and then place an acid-soluble dispersant on top of which the outer dimensions are the same as the steel plate (1) and the above mold release agent A is applied on both sides. Layer the insert plates (2) made of thin copper plates, spread the dispersant evenly on top of them, and then layer another steel plate (1) on top of them and fix them around them. The member (3) is arranged and connected and fixed via the fixing member (3), and as shown in FIG.
), and then this laminate (4) was heated with wet coal at 1000'C for 2 hours and rolled from both outer sides as shown in Figure 1 to form the #IN body (4). The thickness of each of the two steel plates (1) in ) was reduced to 10#Im.

Next, the fixing member [3] at the outer edge of this laminate (4) is removed, the two steel plates 1 (]) are separated, and a part of the insert plate (2) attached to these steel plates (1) is removed. was peeled off and removed. At this time, a part of the insert plate (2) was firmly attached to the steel plate (1), but this was left as it is without being forcefully peeled off.

Next, the two separated steel plates (1) were immersed in a salt f11 solution with a concentration of 35% for about 20 minutes to dissolve and remove the insert plate (2) and the invalidated mixed powder remaining on the surface. The two steel plates (1) that have been subjected to the pickling treatment consisting of acid immersion and neutralization treatment have diamond particles evenly distributed and protruded on the outermost surface of one of them; The base end portions of the particles that did not protrude from the outermost surface of the steel plate (1) were firmly press-fitted and sintered into the surface of the steel plate (1).

Next, these steel plates (1) are processed as shown in FIG. 1C.
A sleeve material (1'') having an outer diameter of 200 mm was formed by bending the surface with the diamond particles protruding outward, and this sleeve material (1') was formed into a sleeve material (1') as shown in Fig. 1d. It was fitted onto the roll core shaft (5) and welded and integrated to form a dull roll having transfer convex portions made of diamond particles that were evenly distributed and protruded on the outer peripheral surface of the roll body.

Then, the dull roll of this example obtained as described above was installed in a small experimental rolling mill, and thereby a cold rolled steel plate with a thickness of 0.71 was tempered at a rolling ratio of 0.8%. While rolling, the surface roughness and sharpness of the steel plate obtained by this temper rolling were investigated in comparison with a steel plate that had been similarly temper rolled using a dull roll using the conventional laser dull method. The survey results are shown in Table 1 as center line average roughness Ra value and filter center line waviness Wca (direction is based on measurement based on JIS standards, and sharpness value is based on measurements taken from the obtained copper plate. A test piece was electrodeposited, cellophane tape was then applied to the test piece, and this was measured using a DOI meter manufactured by ATI SYSTEMS INC.

Further, the directionality of the friction coefficient of the steel plate obtained in this example is shown in the graph of FIG.

As shown in Table 1, the steel plate of this example has a Ra value and a Wca
The value is small, and the sharpness value is also close to that of the steel plate of the comparative example using the Laserdal method. Moreover, as shown in the graph of FIG. 3, the anisotropy of the friction coefficient was also very small, confirming the excellent effect of the present invention.

Above, we have described an example in which the sleeve material (1°) is formed from a steel plate (1) with diamond particles pressed and sintered on one side. As shown in Figures a to 2, the above-mentioned dispersant in which the diamond particles are dispersed and mixed is spread evenly on the outer peripheral surface of the sleeve material (6), which has been previously processed into a cylindrical shape, through a binder. On top of that, an acid-soluble thin steel plate (7) coated with the above-mentioned mold release agent A on one side is wrapped and overlapped with the surface coated with mold release agent A on the inside. Connected and fixed via annular fixing members (8) arranged at both ends to form an integral cylindrical body (9) as shown in Fig. 2a,
Next, this cylindrical body (9) is heated in the same manner as described above, and as shown in FIG.
It is possible to obtain a sleeve material in which diamond particles are evenly distributed and protruded from the outer circumferential surface of the sleeve material.

In the embodiments described above, the diamond particles were pressed and sintered by heating the laminate and the cylindrical body to a high temperature and applying pressure with a roll. , like hot isostatic pressing,
It goes without saying that a method of pressurizing and sintering by applying high pressure via a pressure medium at a high temperature may also be used.

[Effects of the Invention] As described above, according to the dull roll according to the present invention, evenly distributed unevenness can be imparted to the surface of the metal plate to be rolled without in-plane anisotropy, improving image clarity and press processing. Rolled plates with excellent properties can be manufactured.

[Brief explanation of drawings]

Figures 1a to 1d are conceptual diagrams explaining the manufacturing process of a method for manufacturing a dull roll according to an embodiment of the present invention, and Figures 2a to 2 are conceptual diagrams for manufacturing a dull roll according to another embodiment of the present invention. A conceptual explanatory diagram of the method. Figure 3 is a graph showing the directionality of the friction coefficient of a steel plate that has been roughened with a dull roll according to the present invention. Figure 4 is a graph showing the directionality of the friction coefficient of a steel plate that has been roughened with a dull roll according to the conventional laser dulling method. ml of steel plate given! It is a graph showing directionality of coefficients. (1) - Tool steel plate, (2) - Insert plate, (4) - Laminated body, (6) - Sleeve material, (8) - Annular fixing member, Ar - Mold release agent, (1') - Sleeve material, (3)-fixing member, (5)-roll core shaft, (7)-m steel plate, (9)-cylindrical body, D,-monodispersant. Patent applicant Kobe Steel Co., Ltd. Representative Patent attorney Akira Yomitsu

Claims (3)

[Claims] (1) A dull roll characterized by having a transfer convex portion formed by evenly dispersing and implanting diamond particles on the outer peripheral surface of the roll body. (2) Ni powder and/or Cr as a sintering aid
A dispersant made by dispersing and mixing diamond powder into a mixed powder of powder and carbon is applied evenly on the outer circumferential surface of the sleeve material, and then a release agent is applied on one side of the outer circumferential surface of the sleeve material. These thin plates are laminated and coated with the release agent coated side on the inside and fixed. Next, this plate is heated to a high temperature and pressurized from both the inside and outside sides to apply diamond powder to the outer periphery of the sleeve material. After pressing and sintering the surface, the thin plate at the outermost periphery is peeled off and removed, and the sleeve material is pickled to expose the diamond powder on the outer periphery of the sleeve material, and then, A method for manufacturing a dull roll in which the sleeve material is fitted and fixed to a core roll as a roll body. (3) Ni powder and/or Cr as a sintering aid
A dispersant made by dispersing and mixing diamond powder in a mixed powder of powder and carbon is evenly applied on one side of each of two steel plates, and the two steel plates are placed so that the dispersant coated surfaces face each other,
In between, a thin insert plate made of acid-soluble metal coated with a release agent on both sides is placed, laminated and fixed, and then this is heated to a high temperature and pressure is applied from both outer sides to remove the diamond. After the powder is pressed and sintered on one side of each of the two steel plates, the insert plate placed in the middle is peeled off and removed, and the two steel plates are pickled and diamonds are placed on one side of the steel plates. expose the powder,
Thereafter, these steel plates are formed into a cylinder with the surface with the diamond powder exposed on the outside, and the cylinder is fitted and fixed to the roll core shaft as a roll body. .