JPH0747170B2 - Method for forming uneven pattern on the surface of dull roll for steel plate rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has good formability in press working,
In addition, the present invention relates to a method for forming a concavo-convex pattern on the surface of a steel plate or a dull roll for rolling a surface-treated steel plate for producing a steel plate or a surface-treated steel plate having coating clarity.

(Prior Art) It is known that steel sheets used for automobiles and home electric appliances are required to have clearness of paint, which enhances the product value. Conventionally, the improvement of sharpness of paint is an improvement in paint or coating method. Has been emphasized.

On the other hand, a steel sheet for automobiles is given a certain surface roughness by rolling with a dull roll provided with fine irregularities in the manufacturing process in order to improve the adhesion and press workability of the coating material.

In order to perform dull processing on the work roll surface, a shot blasting method of projecting steel grit on the roll surface and an electric discharge machining method of melting the roll surface with discharge energy to form irregularities have been put into practical use.

Further, in recent years, a laser dull processing method using a laser beam having excellent controllability as an energy source for dull processing has been proposed, for example, JP-B-62-1922 or JP-A-63-112086.

(Problems to be Solved by the Invention) In rolling, an uneven pattern on the roll surface is transferred to a steel sheet surface to produce a steel sheet. The press formability of the steel sheet depends on mechanical properties such as r-value and elongation of the steel sheet. In addition, the surface roughness of the steel plate or lubricating oil has a great influence. In general, the lubricating oil accumulated in the concave portions of the concavo-convex pattern is evenly supplied to the convex portions to improve the lubrication condition and prevent press formability, that is, die galling.

On the other hand, increasing the surface roughness lowers the image clarity of the steel sheet and affects the commercial value, so it is considered difficult to achieve both press formability and image clarity.

The present invention provides a method for forming a concavo-convex pattern on the surface of a dull roll for producing a steel plate or a surface-treated steel plate having excellent press formability such as deep drawing and having a sharpness close to a mirror surface.

(Means for Solving the Problems) In the present invention, the surface of a rolling work roll is coated with a photosensitive resist agent or film, and the resist layer is intermittently irradiated with high-density energy while rotating the roll. Harden, wash the uncured part of the roll to form one or more motifs on the roll surface, anisotropically etch the roll with a chemical etchant to form etch pits in the roll base material. , A desired motif is obtained, and then a method of forming an uneven pattern on the surface of the dull roll for steel plate rolling characterized by cleaning and peeling off the resist hardened layer and forming a hard metal plating film on the surface of the work roll for rolling, By coating the surface of the plating film with a photosensitive resist agent or film and irradiating high-density energy intermittently while rotating the roll, The dist layer is cured, the uncured portion of the roll is washed to form one or more motifs on the roll surface, the roll is anisotropically etched with a chemical corrosive agent, and an etch pit is formed in the plated layer. And the desired motif is obtained.

The present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the flow of the present invention.

The work roll 1 for rolling is placed on a rotary table and is rotated, and the photosensitive resist agent 10 is supplied from the hopper 2 during rotation. A squeegee 3 is provided on the lower side in the roll rotation direction to form a uniform layer of the photosensitive resist agent. The hopper 2 and the squeegee 3 are synchronously controlled and moved in the roll axis direction.

The photosensitive resist agent is composed of a polymerization initiator, a photosensitive monomer, a binder polymer, etc., and the photosensitive monomer molecule is polymerized by the irradiated light energy to form a polymer, and a commercially available photoresist can also be used. .

Then, the photosensitive resist layer 9 uniformly coated on the roll 1
Then, a high-density energy source is irradiated. As the high-density energy source, for example, ultraviolet rays or Ar laser 4 can be used to intermittently irradiate through the chopper 5. When a desired rotational movement is given to the chopper 5, the slit 6 provided in the chopper 5 irradiates the laser light at a constant pitch. Therefore, the localized hardening region is continuously formed in the resist layer by intermittent irradiation of the laser beam corresponding to the rotation of the chopper 5.

The resist layer provided with a continuous local curing area is then developed with a sprayer 7 using a developing solution such as trichloroethane 8 to wash away the unirradiated portion to form a motif.

That is, as shown in FIG. 2, a concave motif (main tone) 1 composed of the roll surface 1 ′ and the cured resist layer 9 is formed on the roll surface. Further, since the boundary between the hardened layer and the non-hardened layer of the resist layer is formed extremely sharply, the sharpness of the base material can be obtained during the anisotropic etching of the post-treatment, and the flatness area ratio can be increased. It becomes effective.

According to experiments, if the resist film thickness is 100 μm or less, it is possible to form a hardened layer by laser irradiation.

Further, in the case of a normal rolling roll, when the unevenness step due to anisotropic etching is required to be 10 μm or more, the resist film thickness is preferably in the range of 15 to 30 μm.

In the present invention, etching is performed using a known steel corrosive agent, but etching is anisotropic. Etch pits 21 are formed in the base material by anisotropic etching. For example, when ferric chloride is sprayed onto a shower tablet, the desired anisotropic etching is obtained.

An example of pits formed in the base material by anisotropic etching is shown in FIG.

1 is a roll, 9 is a resist hardening layer, 11 is a concave motif,
21 is an etch pit.

FIG. 4 is an enlarged photograph of the surface of dull roll prepared by the method of the present invention.

According to experiments, the flatness ratio A required to secure high image clarity
It is preferable that ≧ 85%.

In general, the image clarity as the gloss of the baked coating surface is defined as the degree to which the mirror image of the object on the surface is clear and clear. For example, the degree of gloss of the coating film is 60 ° specular gloss test (JIS Z 8741). The flatness A of the present invention is measured by 60 ° specular gloss.

And the steel plate which was given flatness A85% in the conventional steel plate was not discovered until now.

In the present invention, after the motif of the concave motif is obtained on the roll base material, the hardened resist layer is peeled off with a cleaning solution, for example, a strong alkaline solution. An uneven pattern is obtained on the entire surface of the obtained roll. The formation of the motif is regular in a certain pattern, but is not necessarily limited to this. That is, they may be formed in a discontinuous state.

Further, in the steel plate or the surface-treated steel plate rolled by the dull roll manufactured by the method of the present invention, the etch pits formed on the surface of the roll are transferred, and the retaining property of the processing oil is increased during the processing, and the good processing degree is exhibited. For this retention, various sizes and densities are required depending on the viscosity of the processing oil, but the present invention can control them arbitrarily.

Work roll of temper rolling is generally a high carbon forged steel quenching roll, hard metal plating on the dull roll of the present invention,
For example, a Cr, Ni-based plating bath may be used to coat the plating layer.

Next, another example of the present invention will be described.

A method of plating hard chrome on the surface of the work roll is known, but in the present invention, a hard metal coating layer is formed to a thickness of 20 to 50 μm by hard chrome plating.

The surface of the plating roll is coated with a photosensitive resist agent or film, the resist layer is cured by irradiation with high-density energy, and the roll is developed with a developing solution to form a pattern composed of motifs. The process up to this point is the same as the configuration described above.

In the example of the present invention, anisotropic etching with a chemical corrosive agent is performed on the hard chromium plating layer. The etch pits are therefore formed in the plated hard chrome to give the desired motif.

According to the example of the present invention, a dull roll having a hardness different from that of the roll base material can be obtained by selecting a hard metal surface treatment.

Further, the wear of the roll can be improved by coating the roll surface according to the present invention with plating or the like.

Example 1 The surface of a high carbon forged steel quenching roll was coated with a photosensitive resist to form a 40 μm coating layer. After that, laser light was emitted from an Ar laser oscillator.

After forming a φ100 μm hardened region on the photosensitive resist on the roll surface, development processing was performed using a weak alkaline solution. Then, wet etching (main component: ferric chloride) was performed to form a round pattern (Fig. 4) on the roll.

As a result of temper rolling (reduction rate 0.8%) of a cold rolled steel sheet for automobiles having a plate thickness of 0.7 mm with the dull roll of the present invention, the flatness A of the steel sheet was A = 90% and the press formability and the coating sharpness were the conventional examples. It was confirmed that it was superior to the dull roll (steel ball shot blasting method).

Example 2 The surface of a high carbon forged steel roll was plated with hard Cr to obtain a plated layer of 20 μm.

A pattern was formed according to the same specifications as in Example 1 and etching was performed to form an etch pit having a diameter of 100 μm and a depth of 10 μm in the plating layer.

The surface of the roll was stripped of the photosensitive resist with a strong alkaline solution.

The flatness A of the steel sheet rolled by the dull roll was 92% (JIS Z 8741 60 ° specular gloss test).

With the dull roll of the present invention, cold rolled steel sheet for automobiles with a thickness of 0.7 mm was temper-rolled (reduction rate 0.8%), and press formability and coating clarity were higher than those of the conventional example (steel ball shot blast method). And was confirmed to be excellent.

(Effect of the Invention) The present invention irradiates a photosensitive resist agent or a film with a laser beam and develops it with a developing solution to form one or more motifs on the roll surface, and etch pits with a chemical corrosive agent. Since it is formed, it is possible to manufacture a steel plate or a surface-treated steel plate having a high flatness ratio, and it is possible to obtain a steel plate or a surface-treated steel plate having both pressability and paint clarity.

[Brief description of drawings]

FIG. 1 is an explanatory view of the present invention, FIG. 2 is an enlarged explanatory view of part A in FIG. 1, FIG. 3 is an explanatory view of another example of the present invention, and FIG. 4 is a circular pattern by the method of the present invention. It is the schematic diagram which expanded.

Claims (3)

[Claims] 1. A surface of a work roll for rolling is coated with a photosensitive resist agent or a film, and the resist layer is cured by intermittently irradiating high-density energy while rotating the roll. The cured part is washed to form one or more motifs on the roll surface, and the roll is anisotropically etched with a chemical corrosive agent to form an etch pit in the roll base material to obtain a desired motif,
A method of forming a concavo-convex pattern on the surface of a dull roll for steel plate rolling, which comprises washing and peeling the cured resist layer. 2. A hard metal plating film is formed on the surface of a work roll for rolling, a photosensitive resist agent or film is coated on the surface of the plating film, and high-density energy is intermittently irradiated while rotating the roll. To cure the resist layer, wash the uncured portion of the roll to form one or more motifs on the roll surface, and subject the roll to anisotropic etching with a chemical corrosive agent. The method according to claim 1, wherein an etch pit is formed in the film to obtain a desired motif. 3. The anisotropic etching is performed with a chemical corrosive agent to form an etch pit to obtain a desired motif, and after the resist film cured layer is peeled off, a different material is coated on the roll surface. Or the method described in 2.