JPS62110882A - Surface roughening method for cold rolling roller - Google Patents

Abstract

PURPOSE:To give efficiently roughness to the surface of a roller weight deteriorating the dimension accuracy of the roller by providing in advance a black film on the surface of the roller, and thereafter, irradiating a laser beam whose energy density is 5X10<4>-5X10<6>W/cm<2>. CONSTITUTION:When performing a surface roughening working to the surface of a cold rolling roller, a black film is provided in advance on the surface of the roller in order to raise the energy absorption efficiency for the surface roughening working by a pulse laser. That is to say, before irradiating a laser beam from a laser irradiating head 4 to the surface of the roller 1, a black coating film of a uniform film thickness is provided on the surface of the roller by a coater 6, and subsequently, a laser beam whose energy density if 5X10<4>-5X10<6>W/cm<2> is irradiated about vertically to the surface of the roller 1 from the laser irradiating head 4. In this way, by executing a black costing film processing to the surface of the roller prior to the laser surface roughening working, a target roughness can be obtained efficiently by a small energy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for roughening the surface of a cold rolling roll, and more specifically, the present invention relates to a method for roughening the surface of a cold rolling roll, and more particularly, the present invention relates to a method for roughening a cold rolling roll or a temper rolling roll of a metal material into a desired pattern and roughness depth. Concerning a method for roughening the surface.

[Conventional technology]

Surface quality is an important quality of rolled steel sheets, which are metal materials. Surface quality includes beauty, adhesion of paint and enamel, press workability, corrosion resistance, gloss, etc., and the geometric shape of the board, that is, the surface roughness, has an important influence on these properties.

The most common way to obtain a metal surface with the desired surface roughness for each application is to process the surface of a cold roll or/and temper roll roll to a predetermined roughness.
In this method, a steel plate is rolled at a predetermined pressure using these rolls, and the roughness of the roll surface is transferred to the plate surface.

Conventionally widely used methods for roughening the roll surface include (1) shot blasting and electrical discharge machining.

Shot blasting is very simple, and this process also work hardens the roll surface and improves the wear resistance of the roll.
However, there are disadvantages such as uneven roughness, hard rolls require a long processing time, and it is difficult to create deep roughness.

In electrical discharge machining, roughness is controlled by changing the applied voltage and frequency between a rotating roll and an axially moving electrode, but the range of sparks that determines the size of the crater depends on the shape of the electrode. Since it is determined by the dimensions, it is difficult to obtain fine, small-pitch roughness beyond a certain limit. In addition, the convex parts created by electrical discharge machining are mechanically weak.
The initial wear of the rolls during rolling is severe, and the roughness of the transferred plate surface changes drastically.

For the above two methods V:, a processing method using a laser beam (hereinafter referred to as laser dull processing) has recently been proposed. For example, JP 56-160892, JP 58-25
557, JP 54-61043, JP 55-947
90 etc.

All of them describe in detail how to irradiate laser pulses, but do not mention the characteristics of the irradiated roll.

[Problem that the invention seeks to solve]

The inventors began research to industrialize roll surface roughening technology based on laser dulling.

An attempt was made to give the roll surface a target roughness, but it turned out that the target roughness could not be achieved without significantly changing the energy density of the laser beam. As a result of conducting various experiments to investigate the cause, it was found that the roughness varies greatly depending on the surface condition of the roll.

The present invention focuses on this point and provides a method for roughening the surface of a mill roll by efficiently imparting roughness to the roll surface using a pulsed laser.

[Means for solving dark issues]

As a result of extensive research into a method for efficiently obtaining roughness without deteriorating the dimensional accuracy of the roll, the inventor has found that
We have discovered a method for roughening rolling rolls that can provide roll surface roughness extremely efficiently compared to conventional methods.

That is, in the first aspect of the present invention, when roughening the surface of a cold rolling roll, a black coating is applied to the surface of the roll in advance, and then a laser beam with an energy density of 5 x 104 to 5 x 103 W/Cm2 is irradiated. This is a method for roughening a cold roll roll, which is characterized by roughening the roll surface.

Furthermore, the second IJJ of the present invention uses a laser beam having an energy density of 4X 10" W/cm2 or more, which is smaller than the energy density of the laser beam used for surface roughening, in addition to the first invention. It is characterized by being subjected to +1T irradiation resistance heat treatment.

[Effect]

When roughening a cold rolling roll by laser dulling, when roughening the roll surface by irradiating a laser beam with a laser device17, the irradiated part of the roll melts instantaneously, and the melting process occurs. Roughness is imparted by the formation of valleys and peaks of the hole as the metal scatters and bulges around the hole. If the roll surface is irradiated with a laser pulse without any treatment, energy will not be absorbed sufficiently, and as a result, the amount of molten metal will be small, resulting in a low roughness. One effective means for efficiently obtaining roughness is to subject the roll surface to a treatment that increases energy absorption efficiency, and the present invention achieves this by previously applying a black coating.

FIG. 3 shows a comparison of the roughness (Rmax) of the rolls with and without the black coating when irradiated with only the energy density of the laser irradiation conditions being varied. It can be seen that the energy density differs significantly depending on the presence or absence of the black film.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention and its operation will be explained in more detail below with reference to the drawings. - Figures 1 and 2 show an overall view of a surface roughening apparatus that can be suitably used in carrying out the present invention.

The roll l is attached to a roll rotation support device 212 having a configuration similar to that of a machine tool such as a lathe or a grinding machine, and is rotated at a predetermined speed.

On the other hand, the laser beam output from the laser oscillator 3 is irradiated approximately perpendicularly onto the roll surface via a plurality of mirrors. The laser beam is adjusted to a predetermined beam by an optical device, and further focused and narrowed onto the roll surface. The laser irradiation head section 4 can be moved in parallel with the roll axis direction by rotation of the drive screw 5 in synchronization with the roll rotation. The laser beam can be pulsed at a predetermined frequency by a Q-switch or by a mechanical chopper. The pattern and depth of the surface roughness can be controlled by setting the frequency and output of this pulse, the number of rotations of the roll, and the moving speed of the laser irradiation head.

The above configuration is a conventional method for roughening a roll surface using a laser, but the method of the present invention is additionally equipped with a coater 6 for applying a predetermined material to the roll surface and a drive screw for the coater 6. The roll is coated with coater 6 before being irradiated with the laser beam.
The roll is then coated with a black coating film of uniform thickness, and then roughened by the roll roughening laser system 3.4. This surface treatment allows the pulse beam to be efficiently absorbed by the roll surface, making it easy to obtain the target roughness.

A second aspect of the present invention is to harden the roll surface by performing heat treatment by irradiating the roll again with a laser beam having a smaller energy than the laser beam used for surface roughening, following the construction of the first aspect.

At this time, the energy of the laser beam is 4X 10”W
/ crn' or more, a predetermined effect can be obtained.

Next, specific processing conditions will be shown based on Examples.

〔Example〕

The rolling mill used in the experiment was a small laboratory rolling mill, and the diameter of its rolls was 70 mm. A hoop-shaped material was continuously rolled using this roll, and wear of the roll and changes in roughness of the material surface were investigated.

The chemical composition of the rolls used in the experiment was C: 0.85 weight Jit% S i: 0.8 j’j (i1% Mn: 0.4 weight t11% Ni: 0.15 weight 111% Cr: 2.9% by weight Mo: 0.29% by weight V: 0.01 weight% This is a commonly used component system.

The manufacturing process of the roll is as follows.

That is, after casting the molten steel having the components listed in 1.
It was forged at 0°C to a forging ratio of 3.5. Thereafter, a so-called norm treatment of heating to 950° C. and cooling with air was performed. This is 800
After carbide spheroidizing treatment at 700° C. for 10 hours and 10 hours at 700° C., it was machined to predetermined dimensions. a After machining, heated to 900℃, quenched in oil, then heated to 650℃
It was then tempered and machined again to final dimensions. Further, the surface layer was heated to 900° C. by induction heating, quenched in water, tempered at a low temperature of 150° C., and then the final surface was polished.

A roll subjected to such treatment exhibits a healthy structure in which spherical carbides are uniformly distributed in the Marsantate matrix.

The surface of this roll was first coated with black paint using this apparatus, and then roughened to a predetermined roughness by irradiating it with a pulsed CO2 gas laser beam using a mechanical chopper. A commercially available black paint was used.

The laser irradiation conditions are: Laser power: 2KW Pulse frequency: 5BKHz Laser beam diameter: 200m Energy density: 6.4X 10” W/ crn”
Irradiation time per pulse: Pitch of craters formed on the roll surface by irradiation for 13 psec.2 Circumferential direction of the roll.
It is 170 lm in both axial directions. The resulting roll roughness Rmax is approximately 15'4m
It is. On the other hand, when laser irradiation was performed without applying a black film, Rmax was lOILm.

〔Effect of the invention〕

By performing a black coating treatment on the roll surface before laser roughening, the target roughness can be efficiently obtained with less energy. In the example, a black commercially available paint was used, but any black paint such as graphite or amorphous carbon with a binder added would be sufficient to achieve the target.In addition, a roll coater method was used as the black coating device in the example. However, it goes without saying that various methods such as spraying and brushing can be used.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view of a roll surface roughening processing device that can suitably carry out the method of the present invention, Fig. 2 is a cross-sectional view thereof, and Fig. 3 shows the relationship between energy density and Rmax. It is a graph. l... Roll 2... Roll rotation support device 3... Laser oscillator 4... Laser irradiation head 5... Drive screw 6... Coater

Claims (1)

[Claims] 1. When roughening the surface of a cold rolling roll,
After applying a black film to the roll surface in advance, 5 x 10^4 ~
A method for roughening a cold rolling roll, comprising roughening the roll surface by irradiating a laser beam with an energy density of 5 x 10^6 W/cm^2. 2 When roughening the cold rolling roll surface,
After applying a black film on the roll surface in advance, 5 x 10^4 ~
After roughening the roll surface by irradiating it with a laser beam with an energy density of 5 x 10^6 W/cm^2,
Furthermore, the cold rolling roll is heat-treated by being irradiated again with a laser beam having an energy density of 4×10^3 W/cm^2 or more, which is lower than the energy density of the laser beam used for surface roughening. Surface roughening method.