JPH11244905A - Method for adjusting the surface roughness of cold rolls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adjusting the surface roughness of a cold roll, which can suppress the wear of the roll surface roughness and extend the roll life. SOLUTION: A liquid is jetted onto a roll surface during rolling, and the liquid is changed to a saturated vapor pressure or less to obtain a vapor bubble-containing liquid,
The steam bubbles in the steam bubble-containing liquid are broken on the roll surface,
This is a method for adjusting the surface roughness of a cold rolling roll in which the surface of the roll is eroded to adjust the roughness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the surface roughness of a cold roll.

[0002]

2. Description of the Related Art The surface roughness of a cold rolling roll is determined by incorporating a roll formed to a predetermined roughness by shot blasting and electrolytic etching, rolling a metal strip, and abrading a rough surface (convex portion). Rolling is performed by changing to a new roll formed to have a predetermined roughness.

[0003]

As described above, a metal strip such as a steel strip is rolled by forming a roughness on the surface of a rolling roll.
When the continuation of rolling becomes difficult due to wear, the rolling is performed by changing to a new rolling roll with a predetermined roughness, but the operation rate of the rolling mill is reduced by changing the roll to impair productivity. There are issues. The method of the present invention has been made in order to advantageously solve such problems, and adjusts the roughness of the rolling roll surface during rolling to greatly extend the interval between the rolling rolls to be rearranged. It is an object of the present invention to provide a method for adjusting the surface roughness of a cold rolling roll, which can suppress a decrease in the operating rate of a rolling mill due to the above and can increase the productivity.

[0004]

A feature of the method of the present invention is that a liquid is jetted onto the surface of a rolling roll during rolling, and the liquid is changed to a saturated vapor pressure or less to obtain a liquid containing vapor bubbles.
The steam bubbles in the steam bubble-containing liquid are broken on the roll surface,
This is a method for adjusting the surface roughness of a cold rolling roll, which comprises adjusting the roughness by eroding the roll surface.

[0005]

DETAILED DESCRIPTION OF THE INVENTION As described above, in the method of the present invention, a large amount of liquid is ejected through a liquid ejection nozzle at a high speed onto the surface of a rolling roll during rolling, so that the liquid ejected onto the surface of the rolling roll is saturated with steam. The pressure is changed to the pressure or less to generate vapor bubbles (water vapor bubbles) in the liquid to obtain a vapor bubble-containing liquid. Next, the vapor bubble-containing liquid is brought to a high pressure,
Vapor bubbles in liquid containing vapor bubbles are destroyed on the roll surface (crush)
By doing so, the surface energy (surface tension) of the vapor bubbles is released as pressure energy at once, and the surface of the rolling roll is cavitationally eroded to roll the metal strip while constantly adjusting the roughness during rolling. is there.

In order to reliably adjust the roughness of the rolling roll surface during erosion by erosion, for example, as shown in FIG. 1, a liquid jet nozzle 2 is provided on the surface of the rolling metal strip rolling roll 1. The liquid is supplied from the liquid supply pipe 3 and the liquid is jetted to the gap 4 between the liquid jet nozzle 2 and the metal strip 1,
Move like an arrow. In this gap 4, as shown, the liquid flows from the wide gap a to the wide gap c through the narrow gap b.
To discharge the liquid to the outside of the nozzle 2.
In this narrow gap b, the pressure of the liquid becomes low, a part of the liquid becomes lower than the saturated vapor pressure, and vapor bubbles are generated to become vapor-bubble-containing liquid. Next, when moving to the wide gap c, the vapor-bubble-containing liquid becomes higher than the saturated vapor pressure, and the vapor bubbles in the vapor-bubble-containing liquid are destroyed (crushed), thereby breaking (crushing) energy and changing the roll surface. Cavitation erosion and rough surface (convex portion) are worn by rolling, while new rough surface (convex portion) is formed and constantly adjusted to a predetermined roughness during rolling, so that the roll rolls can be changed significantly It is an extension.

That is, the flow rate of the liquid is constant, and the flow velocity of the liquid becomes high in the narrow gap b. At this point, the liquid becomes low pressure according to Bernoulli's theorem, so that part of the liquid becomes lower than the saturated vapor pressure. As a result, a vapor bubble is generated and becomes a vapor bubble-containing liquid. Next, when the liquid moves from the narrow gap b to the wide gap c, the flow velocity of the liquid becomes low, and the liquid becomes higher than the saturated vapor pressure and the vapor bubbles in the vapor-bubble-containing liquid are destroyed (crushed).
Then, it becomes breaking (crushing) energy and cavitationally erodes the roll surface to adjust the roughness of the roll surface.

As described above, the liquid to be supplied and jetted into the gap between the rolling roll and the liquid jet nozzle includes water (industrial water, etc.) and rolling oil (emulsion type, soliable type).
Can be used.

As the rolling roll, for example, a work roll and a backup roll of a continuous cold rolling mill (tandem mill) for a metal strip (steel strip, aluminum strip, etc.), a skin pass mill (skin pass mill), etc. As described above, the surface of the roll is cavitationally eroded by the breaking (crushing) energy of the liquid, and the roll is rolled while adjusting the roughness of the roll surface.

[0010] Thus, the narrow gap liquid ejection nozzle and the metal strip, it is preferable to form a gentle convex curved in 10 to 10 ³ [mu] m. The wide gap is 10 ³ μm
Super is enough. The liquid supply pressure to the liquid ejection nozzle, at a low pressure of 1 to 10 ² MPa, the supply amount from 10 ² to 10 ⁴
By supplying at a large flow rate of 1 / min, the pressure is reduced at a narrow gap portion to change the liquid below the saturated vapor pressure, and steam vapor bubbles are generated to become a vapor-bubble-containing liquid. Then, wide at the gap site vapor bubble-containing liquid in the high pressure, 10 ⁴ ~ than the impact pressure of the liquid flow rate by destroying vapor bubble
10 ⁵ fold destroy (crushing) the energy can be generated. Therefore, the surface roughness of 0.05 to 5.0 Ra generally used for the surface of the rolling roll can be reliably adjusted by erosion.

Next, examples of the method of the present invention will be described together with comparative examples.

[Table 1]

[0012]

[Table 2] (continuation of Table 1)

Note 1: The gap a is the first wide gap between the liquid jet nozzle 2 and the rolling roll 1 shown in FIG. The gap b is a narrow gap. The gap c is a second wide gap. Note 2: Liquid type, A is rolling oil (emulsion type). B is rolling oil (solble type). Note 3: Applicable rolling roll, A is upper and lower work roll of continuous cold rolling mill. B is the upper and lower work rolls of the temper rolling mill. Note 4: In the continuous cold rolling mill, a hot-rolled steel strip (ordinary steel) was rolled in a continuous cold rolling mill, and a thin steel sheet (belt) rolled in a continuous cold rolling mill was rolled in a temper rolling mill. Note 5: In the examples, the rolling roll processed to the surface roughness shown in Table 1 was incorporated and rolled while being adjusted to the processing roughness during rolling. In the comparative example, a rolling roll processed to the surface roughness shown in Table 1 was incorporated and rolled without adjusting the roughness during rolling. Note 6: Continuous use refers to the number of days of rolling used until the surface of the rolling roll is replaced due to abrasion of the roughness surface.

[0014]

According to the method of the present invention, the life of the rolling roll can be greatly extended, the operation rate of the rolling mill by changing the roll can be improved, and the productivity can be increased. In addition, excellent effects such as a reduction in processing cost due to the roll surface roughness can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of the method of the present invention.

Claims (4)

[Claims] 1. A liquid is jetted onto a roll surface during rolling, and the liquid is changed to a saturated vapor pressure or less to obtain a vapor bubble-containing liquid.
The steam bubbles in the steam bubble-containing liquid are broken on the roll surface,
A method for adjusting the surface roughness of a cold rolling roll, wherein the surface of the roll is eroded to adjust the roughness. 2. The method for adjusting the surface roughness of a cold rolling roll according to claim 1, wherein the surface roughness of a work roll or a backup roll of the rolling roll is adjusted. 3. The method for adjusting the surface roughness of a cold rolling roll according to claim 1, wherein water or rolling oil is used as the liquid. Wherein 10 to 10 ³ 1 to 10 ² MPa in the gap between the liquid ejection nozzle and roll set at [mu] m, ejection amount 10
A liquid of ² to 10 ⁴ l / min is supplied and ejected to form a vapor bubble-containing liquid, and then moved to a gap between the liquid ejection nozzle having a diameter of more than 10 ³ μm and a roll to break the vapor bubbles in the vapor-bubble-containing liquid to destroy the roll surface. The method for adjusting the surface roughness of a cold rolling roll according to claim 1, wherein the roughness is adjusted.