JPH07314026A - Method for preventing slip of strip metal of tension roll - Google Patents

Abstract

PURPOSE:To prevent a slip at the time of passing through of the strip metal of a tension roll by spraying gas with a low caking property to a biting portion of the tension roll and the strip metal. CONSTITUTION:Spraying nozzles 4, 4a and 4b for gas with low viscosity, are arranged respectively toward a biting portion of tension rolls 2 formed by combining rolls l, la and lb and the whole width in the width direction of a strip metal 3 moving along with these tension rolls 2. Gas with low viscosity caking property, is sprayed from these spraying nozzles 4, 4a and 4b. In addition, spraying nozzles 4, 4a and 4b to these tension rolls 2, are arranged before and behind skin pass rolling mill, winding reel of the strip metal, unwinding reel, etc. Consequently, the strip metal 3 can be passed through without decreasing the threading speed of the strip metal 3, and a productivity can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing tension band metal band slippage.

[0002]

2. Description of the Related Art A tension roll is used to apply tension (tension) to a metal strip such as a steel strip to perform leveling, rolling, winding, and unwinding. In such a process, if the metal strip slips on the tension roll, the tension cannot be surely applied to the metal strip. Therefore, for example, JP-A-55-1009
As disclosed in Japanese Patent Publication No. 19 and Japanese Patent Publication No. 6-4894, it is known that the roughness of the roll surface is adjusted or the crown of the roll surface is improved to prevent meandering or slippage. There is.

[0003]

However, in the method of adjusting the roughness of the roll surface to prevent slippage and the like, the roughness (irregularities) formed on the roll surface may cause flaws on the surface of the metal strip. In addition, it is disadvantageous in terms of cost to change the roughness of the roll surface in various ways.Furthermore, in the method of improving the crown of the roll surface to prevent meandering, slipping, etc., increasing the amount of crown increases the metal band. Wrinkles may occur in the longitudinal direction, and the cost increase due to the crown change cannot be avoided. In addition, when slips or the like occur during striping, flaws are generated on the surface of the metal strip, so it is necessary to reduce the stripping speed, and there is a problem that the average stripping speed decreases and productivity decreases. The present invention has been made in order to advantageously solve such a problem, and an object thereof is to provide a metal strip slip prevention method for a tension roll that can reliably prevent slip of the metal strip of the tension roll. is there.

[0004]

DISCLOSURE OF THE INVENTION The present invention, which has solved the above-mentioned problems, is characterized in that a low-viscosity gas is blown to the biting portion between the tension roll and the metal strip, and the metal strip slips on the tension roll. It relates to prevention methods.

[0005]

In such a method of preventing the metal strip from slipping on the tension roll, the film thickness of the gas interposed between the metal strip and the roll is reduced by blowing a low-viscosity gas to the biting portion between the tension roll and the metal strip. The gas film is made small and spreads over substantially the entire length of the contact length of the metal strip between the tension roll and the metal strip, thereby preventing slippage of the metal strip. That is, as a result of various studies conducted by the present inventors on the metal band slip of the tension roll, the gas is caught between the tension roll and the metal band by the passage of the metal band, and the thicker the film thickness of the gas film is, the higher the metal content becomes. It was clarified that the frictional force between the strip and the tension roll was reduced, causing slippage and the like. In particular, when the passage speed of the metal strip becomes high, the amount of gas to be entrained between the metal strip and the tension roll increases, so that the amount of increase in the film thickness becomes more remarkable and slips and the like are likely to occur. Furthermore, it was also clarified that the film thickness of the gas interposed between the metal strip and the roll is closely related to the viscosity of the gas.

Therefore, as a result of various experiments on whether or not the slip of the metal strip occurs by spraying so that some gases having different viscosities are intervened on the biting portion between the tension roll and the metal strip, a gas with low viscosity is blown. It was confirmed that by attaching it, the slip of the metal band can be surely prevented. That is, by spraying a low-viscosity gas onto the biting portion between the tension roll and the metal strip to reduce the viscosity of the atmosphere at the biting portion between the tension roll and the metal strip, the gas trapped between the tension roll and the metal strip is The thickness of the formed gas film becomes thin and the metal strip contacts the convex portions of the fine irregularities on the surface of the tension roll, so that the metal strip is accurately passed by the tension roll and slip can be reliably prevented.

Next, as the low-viscosity gas blown to the biting portion of the tension roll and the metal strip, if the viscosity is lower than that of the gas film normally interposed between the tension roll and the metal strip. Good, but for example in the case of air
If it is 1.8 × 10 ^-5 Pa · S or less, the metal band slip can be surely prevented by spraying as described above. In order to obtain such low-viscosity air, the air temperature can be set to 1.8 × 10 ⁻⁵ Pa · S or less by setting the air temperature to about 20 ° C. or less. However, such a low-viscosity gas can be made to have a low-viscosity gas film interposed over the entire contact length of the metal band and the tension roll by spraying as described above. The slip can be prevented. Leveler treatment while applying tension to metal strips such as steel strips with tension rolls.
When processing such as rolling, winding, and rewinding, the gas intervening between the metal band and the tension roll due to the entrainment of the metal band and the entrainment of the rotation of the tension roll is caused by the contact friction between the metal band and the tension roll. The surface part is heated, and the intervening air is heated and becomes highly viscous before and after the contact length of the metal strip and the roll, which causes slippage of the metal strip. By blowing a low-viscosity gas to the biting part of the tension roll, it is possible to reliably prevent the metal band from slipping by interposing a low-viscosity gas film over almost the entire contact length of the metal band and the tension roll. Is.

Next, an example of the method of the present invention will be described with reference to the drawings. In FIG. 1, well-known tension rolls 2 in which rolls 1, 1a, and 1b are combined as shown in the drawing, and the metal strips 3 that move along with these tension rolls 2 are lowered toward the biting portion with the entire widthwise direction. Viscous gas spray nozzles 4, 4a, 4b, 4c are arranged, and the spray nozzles 4, 4a, 4a,
A gas with a lower viscosity than 4b and 4c is blown.
The spray nozzles 4, 4a, 4b, and 4c for the tension roll 2 are arranged before and after the temper rolling mill, the metal band winding reel, the rewinding reel, the looper, and the tension leveler. It can be effectively used for all known tension rolls.

[0009]

EXAMPLE Next, as shown in FIG. 1 on the inlet side and the outlet side of the temper rolling mill.
Roll roughness (Ra) of 3.5 μm and roll diameter of 750 mm
Tension rolls are installed, each with a plate thickness of 0.25 mm and a plate width
850 mm steel strip (C: 0.03% low carbon steel plate) with 2.0 tension on the inlet side
kg / mm², Output side tension 4.0 kg / mm ² When rolling a steel strip under the conditions
The tension roll and the steel strip,
1.8 x 10 cooled from the spray nozzle to below 20 ℃^-FivePa
The results of the rolling treatment were performed while blowing low-viscosity air below S.
As Examples 1 to 4, a low-viscosity gas is blown to the biting part.
Table 1 shows a case where there is no such case as a comparative example. According to this table
Then, in each example, the slip of the steel strip with the tension roll is performed.
High speed rolling with an average strip speed of 1000 m / min.
Whereas the production efficiency could be improved, the bite part
In a comparative example that does not spray a low-viscosity gas
Since the slip occurs, the rolling speed is set at an average rolling speed of 8
Rolling is performed while suppressing slippage at a speed of 00 m / min.
It can be seen that the productivity has decreased.

[0010]

[Table 1]

[0011]

As is apparent from the above description, the present invention is as follows.
By blowing a low-viscosity gas to the biting part between the tension roll and the metal strip, slipping of the metal strip on the tension roll can be reliably prevented, and the strip running speed of the metal strip is not reduced. Since it can be threaded, productivity can be significantly improved. Moreover, since it is not necessary to adjust the surface roughness of the tension roll, the crown, etc., excellent effects such as cost reduction can be obtained. Therefore, the present invention provides an extremely large method for preventing the metal band slip of the tension roll from being brought to the industry as a method of preventing the metal band slip of the tension roll.

[Brief description of drawings]

FIG. 1 is a side view illustrating an embodiment of the method of the present invention.

 ─────────────────────────────────────────────────── --- Continued from the front page (72) Inventor Kenichi Kato 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Inside the Nagoya Works

Claims (2)

[Claims] 1. A method for preventing slippage of a tension roll on a metal strip, which comprises blowing a low-viscosity gas onto a portion where the tension roll and the metal strip are caught. 2. The method for preventing slippage of a metal strip on a tension roll according to claim 1, wherein low-viscosity air of 1.8 × 10 ⁻⁵ Pa · S or less is blown.