JP2000225410A - Method and device for conveying strip in hot rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for conveying hot strips for permitting the prevention of waving by the decrease of deflection centrifugal force between rolls as measure for preventing the waving. SOLUTION: In the conveying method of the hot strip having nozzles for jetting a gas stream to the strip on a run out table on a rolling line for the hot strip, one or more kinds of the contacting/restraining position, roll pitch and guide setting position are adjusted so as to be in the limit of critical waving conditions which are derived from the contact position of the strip with a conveying roll at the time of conveyance, frictional tension between the strip and the conveying roll, roll pitch, installed position of guides, thickness, Young's modulus, width, length and dead weight of the strip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip transport for preventing a strip from waving on a hot run table, and a critical speed is obtained from a phenomenon analysis based on a mechanical balance equation, and a boundary is determined so as to prevent the waving. The present invention relates to a method and an apparatus for transporting a hot strip, in which conditions can be adjusted to achieve high-speed and stable transport of a strip.

[0002]

2. Description of the Related Art In a hot strip after hot rolling, since the strip is thin and has a high transfer speed from a final rolling stand to a winding machine, a transfer roll is provided at the center of the strip. Waving (undulating phenomenon) occurs mainly due to the bending of the plate between the layers, and the floating phenomenon is added to this. On the other hand, frictional tension acts on the plate itself during contact with the transfer rolls, but if the force of the sheet deflection between the transfer rolls overcomes this, the waving (undulation phenomenon) is further emphasized and accelerated. Will occur. This is mainly due to the action of fluid force in the strip flying phenomenon, but waving is largely affected by the plate bending force between the rolls and the frictional tension between the plate and the transport roll, and this is vertical vibration at the rear end, so-called fluttering Will also lead to the occurrence of

As a known technique in this field, for example, Japanese Patent Publication No. 61-1217 discloses a method in which the leading end of a transport strip is placed on a dummy strip and is passed through.
However, in this method, although flying is prevented depending on the shape of the strip tip, waving cannot be prevented. Further, Japanese Patent Application Laid-Open No. H4-138813 discloses a method of generating a thrust while sucking a strip by using an electromagnetic force of a linear motor. Also in this method, both the equipment cost and the power cost tend to increase. Further, Japanese Patent Application Laid-Open No. 7-88554 discloses a method of holding a strip in a floating state by a high-speed gas flow. However, Japanese Patent Application Laid-Open No. H4-13881 discloses
In JP-A-7-88554, the main purpose is to prevent flying immediately before or in the vicinity of the winder, and not to the front of the hot run table near the final stand.

[0004] Even in the prior art described above, it is impossible to sufficiently prevent waving, and a technology has been developed to prevent waving and fluttering due to high-speed conveyance, thereby suppressing a reduction in the sheet passing speed and improving productivity. Is desired. Furthermore, it is desired to realize the approach of equipment such as a cooling nozzle in a hot run table and the improvement of cooling capacity by preventing waving and fluttering.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to examine a mechanism for preventing a waving phenomenon at a central portion of a strip conveyed at a high speed on a hot run table from its mechanism, and to derive a critical waving speed from a mechanical balancing equation. And
Provided are a method and an apparatus for conveying a hot strip which can be controlled in an area where waving does not occur.

Another object of the present invention is to provide a method and apparatus for conveying a hot strip which can be prevented by reducing the bending centrifugal force between the rolls as a measure for preventing the waving. Another object of the present invention is to provide a hot strip capable of realizing a preventive measure by applying fluid or mechanical tension as a measure for preventing the waving, by examining various tension applying devices for applying a tension in the direction of passing the sheet. Provide a transport method and equipment.

[0007] Another object of the present invention is to provide a hot-rolling device capable of preventing waving and fluttering, which are hindrance factors for increasing the running speed of a thin strip, and improving productivity. And a method and apparatus for transporting a strip.

[0008]

The gist of the present invention to achieve the above object is as follows. (1) In a hot strip conveying method having a nozzle for injecting a gas flow into the strip on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, the strip is conveyed while being conveyed. Within the limits of the webbing critical conditions derived from the transport roll contact position, the frictional tension between the strip and the transport roll, the roll pitch, the guide installation position, and the strip thickness, Young's modulus, strip width, length and strip weight Thus, one or more of the contact restraint position, the roll pitch, and the guide setting position are adjusted.

(2) In a method of transporting a hot strip on a run-out table between a final stand and a down coiler for winding the strip in a hot strip rolling line, a contact position of the strip with a transport roll when the strip is transported, The frictional tension with the transport roll, the roll pitch, the guide installation position, and the contact restraint position, so as to be within the limits of the webbing critical conditions derived from the strip thickness, Young's modulus, plate width, length and the plate's own weight, One or two of roll pitch and guide setting position
A method for transporting a hot strip, comprising adjusting at least one kind.

(3) On a hot strip transporting facility having a nozzle for injecting a gas flow into the strip on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, Means for deriving a webbing critical condition from the transport roller contact position of the strip, the frictional tension between the strip and the transport roll, the roll pitch, the guide installation position, and the thickness, Young's modulus, width, length and weight of the strip. A means for adjusting one or more of the contact restraint position, the roll pitch, and the guide setting position so as to be within the limits.

(4) In a hot strip transfer facility on a run-out table between a final stand and a down coiler for winding the strip in a hot strip rolling line, a contact position of the strip with a transfer roll when the strip is transferred, Contact with the means to derive the webbing critical condition from the friction tension with the transport roll, the roll pitch, the guide installation position, and the strip thickness, Young's modulus, plate width, length and the plate's own weight, so that it is within its limits A hot strip transport facility comprising means for adjusting one or more of a constraint position, a roll pitch, and a guide setting position. (5) On a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, gas supply means for supplying a gas flow at a predetermined elevation angle, cooling of the strip and feeding of the strip to a transport roll. A hot strip transporting facility, further comprising cooling fluid supply means for applying a pressing force.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the strip conveying method in hot rolling according to the present invention, the present inventors have obtained new knowledge by analyzing waving as follows, and as a result, have achieved the present invention. 2 (a) and 2 (b) show a waving phenomenon and a method for preventing the waving phenomenon. FIG. 2 (a) shows a centrifugal force generated by the bending of the sheet between the conveying rolls and the sheet passing speed. Increase. (B) shows that the deflection between the rolls is reduced by applying the tension in the transport direction by the transport rolls or the external force, thereby reducing the limit speed of the waving occurrence. In the numerical analysis model of the present invention, Expression 1 is used as a basic expression as a waving critical velocity analysis expression.

[0013]

(Equation 1)

In a special case where the above-mentioned basic equation is solved and the tension acting on the plate is completely ignored, Equation 2 is obtained as an equation giving the critical speed of waving.

[0015]

(Equation 2)

The equation for applying tension is given by Equation 3 as an equation that gives the critical speed of waving for applying tension from the above basic equation.

[0017]

(Equation 3)

FIG. 1 is a diagram showing the effect of the apron between the transport rolls of the present invention. In this figure, the critical speed boundary is obtained from the above numerical analysis, and it can be seen that the waving is suppressed when the critical speed boundary is below this straight line. When the roll pitch is small, the critical speed boundary shifts to the high speed side, and the allowable control limit is widened. Even with the apron between the transport rolls, the control tolerance limit is also widened,
Effectively works to suppress waving. This indicates that the installation of the apron between the rolls has the effect of halving the roll pitch, and the critical webing speed is reduced.

Hereinafter, the present invention will be described in more detail based on examples.

[0020]

FIG. 4 shows an outline of an air jet apparatus according to this embodiment. The cooling nozzle 6 and the levitation suppressing nozzle 8 are disposed immediately above the transport roll 2, and air is jetted in the transport direction 4 on the transport steel sheet 1. The condition of air jet is nozzle width: 600
mm, slit width: 5 mm, air ejection speed: 200 m /
s, air ejection flow rate: 35 Nm ³ / min. FIG. 3 shows the results of the air jet device of the present embodiment. In the air jet effect generating portion, the inter-roll apron of this embodiment is provided at a position 5 mm from the roll path with respect to the transport roll. By providing air jets and aprons,
The flying height is reduced to about 40 mm or less even at 1100 mpm, which is 1/4 of the case where no countermeasures for waving are taken.
About 1/7. This reduction effect is １ ／ of the roll pitch in the aforementioned waving critical speed analysis model.
This is due to the increase in frictional tension caused by the pressing of the plate by the air jet, and it can be seen that waving can be suppressed by implementing these measures.

[0021]

According to the present invention, a hot-rolled thin material (1.2
(3.0 mm) material can be stably conveyed at high speed, productivity and yield can be improved, and quality can be improved by increasing the precision of the product shape. In addition, by the high-speed conveyance, an improvement in the working rate and an improvement in the process management ability for the next process can be expected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a critical speed based on a critical waving speed line according to the present invention.

FIG. 2 is a view showing a model of a simulation of numerical analysis of waving according to the present invention, in which (a) an occurrence phenomenon and (b) a case of applying tension.

FIG. 3 is a diagram illustrating a relationship between a passing speed and a waving floating amount according to a third embodiment of the present invention.

FIG. 4 is a diagram showing an outline of equipment related to an air jet according to a third embodiment of the present invention.

FIG. 5 is a view showing an apron between transfer rolls according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Steel plate 2 ... Transport roll 3 ... Apron 4 ... Transport direction 5 ... Cooling water jet 6 ... Cooling nozzle 7 ... Air jet 8 ... Floating suppression nozzle 9 ... Air piping 10 ... Cooling water piping

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Ogawa 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Takeshi Higo 20-1 Shintomi, Futtsu-shi, Chiba New Japan Steel Technology Co., Ltd.

Claims (5)

[Claims] 1. A hot strip transport method comprising a nozzle for injecting a gas stream onto a strip on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, wherein the hot strip is transported. Within the limit of the webbing critical condition derived from the contact position of the strip transfer roll, the frictional tension between the strip and the transfer roll, the roll pitch, the guide installation position, and the strip thickness, Young's modulus, strip width, length and strip weight A hot strip conveying method characterized by adjusting one or more of a contact restraining position, a roll pitch, and a guide setting position such that 2. A hot strip conveying method on a run-out table between a final stand and a down coiler for winding a strip in a hot strip rolling line, wherein the strip is conveyed at a conveying roll contact position, and the strip is conveyed. The contact restraining position and the roll must be within the limits of the webbing critical conditions derived from the friction tension with the roll, the roll pitch, the guide installation position, and the strip thickness, Young's modulus, strip width, length and strip weight. A hot strip transport method comprising adjusting one or more of a pitch and a guide setting position. 3. A hot strip transfer facility having a nozzle for injecting a gas stream onto a strip on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, the strip being transported. A means for deriving a webbing critical condition from the strip's transport roll contact position, the frictional tension between the strip and the transport roll, the roll pitch, the guide installation position, and the strip's thickness, Young's modulus, plate width, length, and its own weight, One or two of the contact restraint position, roll pitch and guide setting position so as to be within the limit.
A hot strip transport facility comprising means for adjusting the number of species. 4. In a hot strip transfer facility on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, a contact position of a transfer roll of the strip when the strip is transferred, a strip and a transfer. Means for deriving critical webbing conditions from the friction tension with the roll, roll pitch, guide installation position, and strip thickness, Young's modulus, strip width, length and strip weight, and contact constraints so that they are within the limits A hot strip transport equipment comprising means for adjusting one or more of a position, a roll pitch, and a guide setting position. 5. A gas supply means for supplying a gas flow at a predetermined elevation angle on a run-out table between a final stand in a hot strip rolling line and a down coiler for winding the strip, and a cooling and conveying roll for the strip. A hot strip transporting facility, further comprising cooling fluid supply means for applying a pressing force to the strip.