JP2002180232A - Separator roll and cold rolling method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator roll for manufacturing a steel strip having an excellent surface characteristic by preventing a scratch generated by the withdrawal action of the separator roll in a looper equipment or a biting flaw caused by foreign matter generated from the separator roll and a cold rolling method using the same. SOLUTION: The looper equipment having the separator roll having a surface coated with a WC thermal spraying material is arranged in the inlet side of a cold rolling equipment and the cold rolling is carried out while controlling the tension given to a pickled hot rolled steel strip by the looper equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separator roll of a looper facility provided between a pickling facility and a cold rolling facility, and a cold rolling method using the same.

[0002]

2. Description of the Related Art Generally, in cold rolling of a hot-rolled steel strip, a hot-rolled steel strip as a raw material is pickled to remove scale on its surface, and then hot-rolled by using a looper facility. Cold rolling is performed while adjusting the tension applied to the strip. FIG. 1 is a layout diagram illustrating an example of a looper facility and a cold rolling facility. Arrows in FIG. 1 indicate the transport direction of the hot-rolled steel strip.

[0003] The hot-rolled steel strip 1 is provided with a pickling facility (not shown).
After being pickled in the above, it is fed to the looper facility 3 via the bridle roll 2. Usually, since the passing speed of the pickling equipment and the rolling speed of the cold rolling equipment 8 are different, the speed difference is adjusted to continuously process the hot-rolled steel strip 1 with these equipments,
It is necessary to appropriately maintain the tension applied to the hot-rolled steel strip 1. Therefore, pickling equipment (not shown) and cold rolling equipment 8
The looper equipment 3 is arranged in the middle of the hot rolled steel strip 1
Adjust the tension applied to.

The looper equipment 3 is disposed on the outlet side of the pickling equipment (not shown), on the inlet side of the cold rolling equipment 8, or in the middle between the pickling equipment (not shown) and the cold rolling equipment 8. Is done. Here, an example will be described, which is provided between the pickling equipment (not shown) and the cold rolling equipment 8. The looper equipment 3 includes a looper car 5 for freely moving the roll unit in the longitudinal direction of the hot-rolled steel strip 1 and a roll 6 fixed at a fixed position.
(Hereinafter, referred to as a fixed roll 6). The fixed roll 6 is fixed in place, while the looper car 5 can move in the longitudinal direction of the hot-rolled steel strip 1, so that the looper equipment 3
The length of the hot-rolled steel strip 1 in the inside can be changed.
Thus, by adjusting the difference between the threading speed of the pickling equipment and the rolling speed of the cold rolling equipment 8 and maintaining the tension applied to the hot-rolled steel strip 1 properly, the hot-rolled steel strip 1 is Continuous cold rolling becomes possible.

When the distance between the looper car 5 and the fixed roll 6 is increased by moving the looper car 5 away from the fixed roll 6, the hot-rolled steel strip 1 between the looper car 5 and the fixed roll 6 is moved. In order to prevent loosening, the separator roll 4 is brought into contact with the lower surface of the hot-rolled steel strip 1 to support the hot-rolled steel strip 1. However, when the looper car 5 moves in the direction approaching the fixed roll 6, the separator roll 4 is retracted so as not to interfere with the looper car 5.

[0006] The separator roll 4 is a hot rolled steel strip 1
When moving from the position in contact with the lower surface of the steel strip to the evacuation position or from the evacuation position to the lower surface of the hot-rolled steel strip 1 (hereinafter referred to as the evacuation operation), the lower surface of the hot-rolled steel strip 1 may have scratches or the like. Surface flaws occur. Therefore, in order to prevent surface defects of the hot-rolled steel strip 1, a roll (hereinafter, referred to as a rubber roll) whose roll surface is coated with urethane rubber is used as the separator roll 4.

However, the rubber roll is replaced with the separator roll 4
When used, degraded urethane rubber fragments (hereinafter referred to as rubber scraps) adhere to the hot-rolled steel strip 1 during operation of the looper facility 3. When rubber scraps are attached to the hot-rolled steel strip 1 and fed to the downstream bridle roll 7 or the cold-rolling equipment 7, the rubber scraps are crimped, so that the cold-rolled steel strips are damaged. Occurs.

Japanese Patent No. 2624599 discloses a method for treating a strip-shaped metal body having excellent surface properties. This technology uses a high-pressure water containing abrasive grains on a band-shaped metal body with a scale on the surface, and then performs heavy-grinding with ultra-high-pressure water containing abrasive grains larger than the abrasive grains of the heavy grinding, thereby reducing the surface. An object is to obtain a strip-shaped metal body having excellent properties. However, in this technique, the scale adhered to the band-shaped metal body by the abrasive grains is not sufficiently removed by the ultra-high pressure water, and the abrasive grains contained in the ultra-high pressure water also adhere to the band-shaped metal body and remain.

JP-A-11-158669 discloses a thermal spray roll for a continuous pickling line. This technique aims to extend the roll life by using a roll whose surface is sprayed with WC when pickling and removing scale generated on the surface of a steel sheet after hot rolling. However, in this technique, when removing foreign matter such as scale attached to the surface of the steel sheet after pickling, a conventionally known technique is applied, so that the foreign matter is not sufficiently removed.

[0010] Japanese Patent No. 2624599 and JP-A-11-158669
When cold rolling is performed on a band-shaped metal body or a steel sheet obtained by the technique described in Japanese Patent Application Publication No. H10-15083 through a conventionally known looper facility, foreign matter remaining on the surface of the band-shaped metal body or the steel sheet bites. There is a problem that dents occur.
Japanese Patent Application Laid-Open No. H11-267734 discloses a swing roll used in a continuous pickling facility. This technology is
The present invention relates to a swing roll that is installed to support a steel strip loop of a loop car facility, and at least a body part of the swing roll that is in contact with the steel strip is made of a silicon nitride-based sintered body, thereby extending the life of the swing roll and It is intended to improve the resistance to rough skin. However, in this technique, since the body of the swing roll is a silicon nitride sintered body, the toughness is low, and a crack occurs in the swing roll,
There was a problem that the cracks were transferred to the steel strip.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to prevent the scratches caused by the retreating operation of the separator roll of the looper equipment and the dents caused by the foreign matter generated from the separator roll. It is another object of the present invention to provide a separator roll for producing a steel sheet having excellent surface properties, and a cold rolling method using the same.

[0012]

SUMMARY OF THE INVENTION In order to investigate the cause of the occurrence of cracks on a cold-rolled steel strip, the present inventor uses a conventionally known rubber roll as a separator roll to form a hot-rolled steel strip. Was subjected to cold rolling, and foreign matters remaining on the surface of the steel strip after the cold rolling were collected, and the components were analyzed by infrared spectroscopy. As a result, it was found that most of the foreign matters were rubber chips having the same components as the urethane rubber used for the rubber roll.

[0013] Therefore, when a roll whose surface is coated with a sprayed material of WC (that is, tungsten carbide), which is higher in hardness than the hot-rolled steel strip and does not generate wear powder, is used as a separator roll, the cold-rolled steel after cold rolling is used. It has been found that it is possible to prevent the strip from being scratched and to prevent the hot rolled steel strip from being scratched when the separator roll performs the retreat operation in accordance with the movement of the looper car.

[0014] The present invention relates to a separator roll of a looper facility which is disposed on an outlet side of a pickling facility, an inlet side of a cold rolling facility, or between a pickling facility and a cold rolling facility. It is a separator roll whose surface is coated with a material. The present invention also provides a looper facility having a separator roll whose surface is coated with a sprayed material of WC, an outlet side of a pickling facility, an entrance side of a cold rolling facility, or a space between the pickling facility and the cold rolling facility. This is a cold rolling method for performing cold rolling of a hot-rolled steel strip using a cold rolling facility while adjusting tension applied to the pickled hot-rolled steel strip by the looper facility.

[0015] In the invention of the cold rolling method described above,
As a first preferred embodiment, it is preferable to wash the surface of the hot-rolled steel strip by blowing high-pressure air or high-pressure water to the hot-rolled steel strip between the looper equipment and the cold-rolling equipment. As a second preferred embodiment, it is preferable to clean the surface of the hot-rolled steel strip using a brush roll disposed between the looper facility and the cold rolling facility.

[0016]

FIG. 1 is a layout diagram showing an example of a looper facility and a cold rolling facility to which the present invention is applied. Arrows in FIG. 1 indicate the transport direction of the hot-rolled steel strip 1. The hot-rolled steel strip 1 is pickled by a pickling facility (not shown), and then sent to a looper facility 3 via bridle rolls 2. Normally, since the passing speed of the pickling equipment and the rolling speed of the cold rolling equipment 8 are different, the speed difference is adjusted in order to continuously process the hot-rolled steel strip 1 with these equipments, It is necessary to properly maintain the tension applied to the belt 1. Therefore, the looper equipment 3 is disposed between the pickling equipment and the cold rolling equipment 8 to adjust the tension applied to the hot-rolled steel strip 1.

The looper equipment 3 has a looper car 5 for freely moving the roll unit in the longitudinal direction of the hot-rolled steel strip 1 and a fixed roll 6 fixed at a fixed position. The fixed roll 6 is fixed in place, while the looper car 5 can move in the longitudinal direction of the hot-rolled steel strip 1, so that the length of the hot-rolled steel strip 1 in the looper equipment 3 can be changed. . Thus, the feed speed of the pickling equipment and the cold rolling equipment 8
The tension applied to the hot-rolled steel strip 1 is appropriately maintained by adjusting the difference from the rolling speed of the hot-rolled steel strip 1, and the hot-rolled steel strip 1 is continuously cold-rolled.

When the looper car 5 moves in the direction away from the fixed roll 6 and the interval between the looper car 5 and the fixed roll 6 is widened, the hot-rolled steel strip 1 between the looper car 5 and the fixed roll 6 is moved. In order to prevent loosening, the separator roll 4 is brought into contact with the lower surface of the hot-rolled steel strip 1 to support the hot-rolled steel strip 1. However, when the looper car 5 moves in the direction approaching the fixed roll 6, the separator roll 4 is retracted so as not to interfere with the looper car 5.

When the looper car 5 moves away from the fixed roll 6, the separator roll 4 moves from the retracted position to the lower surface of the hot-rolled steel strip 1 again.
In this way, the separator roll 4 repeats the retreat operation in accordance with the movement of the looper car 5. The separator roll 4 is obtained by spraying WC on the surface and coating the surface with a WC spray material. Since the WC sprayed material has a higher hardness and a higher wear resistance than the hot-rolled steel strip 1, there is no problem that the WC sprayed material is deteriorated or damaged during the passing of the hot-rolled steel strip 1. Therefore, the fragments of the WC sprayed material do not adhere to the hot-rolled steel strip 1 and the cold-rolled steel strip can be prevented from being scratched. Also, when the separator roll 4 performs the retreat operation in accordance with the movement of the looper car 5, the scratches on the hot-rolled steel strip 1 can be prevented.

Although WC is a material having low toughness, it is used by spraying onto the surface of the separator roll 4, so that the toughness of the separator roll 4 does not decrease, and the hardness and wear resistance of the WC sprayed material coated on the surface are reduced. Therefore, the life of the separator roll 4 of the present invention is longer than that of a conventionally known rubber roll. When cold rolling is performed using the separator roll 4 of the present invention in the looper facility 3 disposed on the entrance side of the cold rolling facility 8 in this way, surface defects (such as cracks and scratches) on the cold-rolled steel strip are obtained. Can be prevented,
A cold-rolled steel strip having excellent surface properties can be obtained.

In the present invention, a spray nozzle 10 is provided between the looper equipment 3 and the cold rolling equipment 8 in order to sufficiently remove fine foreign matter adhering to the hot-rolled steel strip 1. Preferably, compressed air or high-pressure water is blown onto the hot-rolled steel strip 1. A conventionally known brush roll 9 may be provided between the looper facility 3 and the cold rolling facility 8. Spray nozzle 10 and brush roll 9
Each may be provided independently, or both may be provided as shown in FIG.

When the spray nozzle 10 and the brush roll 9 are used in combination, the arrangement order is not particularly limited. However, as shown in FIG. 2, if the hot-rolled steel strip 1 is first washed with the brush roll 9 and then further washed with the spray nozzle 10, the effect of removing foreign substances increases. FIG. 2 shows an example in which the brush roll 9 and the spray nozzle 10 are arranged between the bridle roll 7 and the cold rolling equipment 8 on the downstream side of the looper equipment 3. A brush roll 9 and a spray nozzle 10 may be disposed between the above-mentioned bridle roll 7 and the bridle roll 7.

[0023]

[Example] Hot-rolled steel strip 1 (JIS G3141 SPCC equivalent,
After pickling a steel sheet having a width of 1200 mm and a thickness of 3.5 mm), cold rolling was performed using a looper facility 3 while adjusting the tension applied to the hot-rolled steel strip 1 as shown in FIG. As the separator roll 4 of the looper facility 3, a roll whose surface was coated with a WC spray material was used. This is referred to as Inventive Example 1.

An example in which a brush roll 9 is disposed between the bridle roll 7 and the cold rolling equipment 8 on the downstream side of the looper equipment 3 to perform cold rolling is referred to as Invention Example 2, and FIG. Inventive Example 3 is an example in which a spray nozzle 10 is arranged between the brush roll 9 and the cold rolling equipment 8 and compressed air is blown onto the hot-rolled steel strip 1 to perform cold rolling as shown in FIG.

In the invention example 3, the spray nozzle 10
The vertical distance between the hot-rolled steel strip 1 and the hot-rolled steel strip 1 is 200 mm, and the injection pressure of the compressed air is 0.4 kg / cm ² . The direction has an angle of 45 ° toward the upstream side (that is, the direction of the brush roll 9). As a comparative example, a hot-rolled steel strip 1 (JIS
G3141 SPCC equivalent, 1200mm wide, 3.5mm thick) After pickling, the tension acting on the hot-rolled steel strip 1 was adjusted using a looper facility 3 using a conventionally known rubber roll as a separator roll 4. While cold rolling was performed.

With respect to Inventive Examples 1 to 3 and Comparative Examples, the surface of the cold-rolled steel strip after the completion of the cold rolling was visually inspected for dents and the occurrence rate (%) of the dents was determined by the following (1). It was calculated by the formula. The results are as shown in Table 1. Number of occurrence of dents (%) = 100 × [N ₁ / (N ₁ + N ₂ )] (1) N ₁ : Length of steel strip where dents occur (m) N ₂ : Number of dents Length of steel strip not generated (m)

[0027]

[Table 1]

When the invention examples 1 to 3 are compared with the comparative examples, the occurrence rate of the dents of the invention examples 1 to 3 was 0.022 to 0.029%, whereas the comparative example was 0.1%. In No. 3, the dents were suppressed. In addition, in the case of the invention example 1 in which the conventionally known brush roll 9 and the spray nozzle 10 were not disposed between the looper facility 3 and the cold rolling mill 8, the rate of occurrence of dents was 0.029%. Inventive Example 2, in which the roll 9 was provided, had an occurrence rate of 0.025%, and Inventive Example 3, in which the brush roll 9 and the spray nozzle 10 were provided, had an occurrence rate of 0.022%. It was confirmed that the disposition of the nozzle 9 and the spray nozzle 10 exhibited a more remarkable effect of suppressing dents and flaws.

When the surface of the cold-rolled steel strip after the completion of the cold rolling was visually inspected for Invention Examples 1 to 3, no flaws were found.

[0030]

According to the present invention, a cold-rolled steel strip having excellent surface properties can be manufactured by preventing surface defects of the cold-rolled steel strip.

[Brief description of the drawings]

FIG. 1 is a layout diagram showing an example of a looper facility and a cold rolling facility.

FIG. 2 is a layout diagram showing an example in which a brush roll and a spray nozzle are used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot-rolled steel strip 2 Bridle roll 3 Looper equipment 4 Separator roll 5 Looper car 6 Fixed roll 7 Bridle roll 8 Cold rolling equipment 9 Brush roll 10 Spray nozzle

Claims (4)

[Claims] 1. A separator roll of a looper facility disposed on an outlet side of an pickling facility, an inlet side of a cold rolling facility, or between a pickling facility and a cold rolling facility, and is a WC sprayed material. A separator roll having a surface coated. 2. A pick-up facility, comprising: a looper device having a separator roll whose surface is coated with a WC spray material;
The cold rolling equipment is disposed between the cold rolling equipment or the pickling equipment and the cold rolling equipment, and the tension applied to the pickled hot-rolled steel strip is adjusted by the looper equipment. Cold rolling of the hot-rolled steel strip using the method described above. 3. A high-pressure air or high-pressure water is sprayed on the hot-rolled steel strip between the looper equipment and the cold-rolling equipment to clean a surface of the hot-rolled steel strip. The cold rolling method according to claim 2. 4. The surface of the hot-rolled steel strip is cleaned by using a brush roll disposed between the looper facility and the cold-rolling facility.
The cold rolling method according to 1.