JP3134453B2 - Strip cooling device for continuous annealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip cooling apparatus for rapidly cooling a strip by a cooling roll for continuous annealing.

[0002]

2. Description of the Related Art In a roll cooling method for a strip performed in a continuous annealing facility, a cooling roll having a structure in which a spiral groove is usually provided inside and a coolant such as cooling water passes through the groove is used. .

FIG. 14 shows an example of a structure of a quenching facility for continuous annealing of a strip X using a plurality of cooling rolls 1a to 1e. The quenching equipment has a structure in which each of the cooling rolls 1a to 1e can move in a direction perpendicular to the strip pass line, and by these movements, the contact area with the strip X is changed to obtain a predetermined temperature drop. Is available.

[0004]

However, in the roll cooling equipment as described above, cooling unevenness such as an increase in the temperature of the strip edge is apt to occur, and the temperature distribution in the strip width direction is not uniform. If the temperature distribution in the plate width direction becomes non-uniform, the shape of the strip X will be lost, and meandering and squeezing will occur in the overaging furnace at the subsequent stage, which will significantly impair the stable operation of the furnace. . In addition, when such temperature distribution non-uniformity occurs, there is a problem that an important aging index among the materials of general cold-rolled steel sheet is partially inferior at the edge portion and the like, and only products having non-uniform material in the width direction can be manufactured. I was

The present invention has been made in view of the above-mentioned problems of the prior art. In a cooling apparatus for performing roll cooling for continuous annealing of a strip, a temperature profile in a strip width direction is improved and uniformity is improved. It is intended to obtain a stable product of the material.

[0006]

SUMMARY OF THE INVENTION Therefore, a strip cooling device for continuous annealing according to the present invention has bridle rolls disposed on the inlet side and the outlet side of a cooling roll group, respectively, and a bridging roll is provided between the cooling roll cluster side and the outlet bridle roll. In addition, a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is provided, and a sheet thermometer capable of measuring the temperature profile in the strip width direction is installed on the outlet bridle roll side, and based on the measured value of the sheet thermometer. A basic feature is that a control arithmetic unit for adjusting the cooling amount in the strip width direction of the gas jet nozzle is provided.

The above configuration is based on the present inventors' elucidation of the cause of the problem in the prior art, and the elucidated cause will be described in detail below.

[0008] It is presumed that unevenness in cooling in the conventional configuration mainly occurs due to low contact pressure between the cooling roll and the strip. In particular, as shown in FIG. 7, by winding the strip X around a chill roll to give a curvature R, the roll contact side of the strip X receives a tensile stress in the roll axis direction and the opposite side receives a compressive stress. As a result, as shown in FIG. 8, a portion H that does not completely contact the cooling roll 1 occurs at the edge of the strip X. As shown in FIG. 9, the edge floating amount H tends to increase when the strip tension of the cooling roll is small. Due to the above-mentioned phenomena, a strip edge portion has a high temperature distribution as shown in FIG. 10, and as shown in FIG. Manufactured or
The meandering and narrowing of the furnace due to the strip shape collapse occurred, resulting in a problem that stable operation was not possible.

An object of the present invention is to provide a tension applying device such as a bridle roll capable of applying a tension to a strip before and after a group of cooling rolls (for example, to reduce the strip tension by 1).
(from 3 kgf / mm ² to 3 kgf / mm ² ), the amount of edge floating can be reduced to about half. Further, complete cooling of the edge cannot be expected only by applying tension to the strip, and a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is arranged between the cooling roll cluster side and the outlet bridle roll. By measuring the temperature by a sheet thermometer that measures the width direction temperature profile arranged on the outlet bridle roll side, by sending the measurement signal to a control arithmetic unit to control the cooling amount in the strip width direction, A uniform temperature distribution can be obtained.

On the other hand, as shown in FIG. 12A, in a plurality of cooling rolls, if the cooling amount of the roll that comes in contact with the strip later is larger than the cooling amount of the roll that comes earlier. The high temperature portion of the edge as shown in (b) extends to the center of the plate width, the cooling load of the gas jet nozzle installed on the exit side of the cooling roll group becomes large, and the portion with poor aging is the plate. It will enter up to the center of the width. For this reason, in the present invention, the cooling amount of the earlier-ordered roll that comes into contact with the strip as shown in FIG.
As shown in (b), the high-temperature portion of the edge can be prevented from reaching the center of the plate width.

In order to improve the cooling capability of the gas jet nozzle for edge cooling, the blowing gas is H ₂ 40-90%, N ₂
It is good to use in the range of 10-60%.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 1 is an explanatory view showing a horizontal roll cooling apparatus in a continuous strip annealing facility to which an embodiment of the present invention is applied.

The strip X, which has been heated and soaked and further cooled down, enters the roll cooling device and is cooled by the cooling rolls 1a to 1a.
It will be cooled in 1e and sent to the next overage treatment. Among these, in the present roll cooling device, a plate thermometer 40 for measuring the inlet plate temperature is provided in front of the entrance-side deflector roll 60, and the measured value is input to the control arithmetic unit 5 described later,
The control arithmetic unit 5 calculates the roll cooling amount based on the inlet plate temperature, the target outlet plate temperature input in advance, the strip size, the line speed, and the like. Based on this calculation, the control arithmetic unit 5 gives a command to each of the roll winding angle adjusters 10a to 10e of each of the cooling rolls 1a to 1e so that the cooling amount of each roll can be adjusted.

In this embodiment, bridle rolls 2a and 2b are arranged on the inlet and outlet sides of the cooling rolls 1a to 1e, respectively, and the cooling roll 1e (more precisely, the deflector roll 61) and the outlet bridle roll 2b are arranged. Gas jet nozzle 3a, 3b between
And a plate thermometer 4 capable of measuring a temperature profile in the strip width direction comprising a multiple reflection thermometer and a radiation thermometer is installed on the exit side bridle roll 2b side, and furthermore, the outlet plate temperature profile is controlled and controlled by an arithmetic unit 5 Is being entered. The control arithmetic unit 5 adjusts the roll cooling amount as described above, determines the cooling amount in the width direction of the gas jet nozzles 3a and 3b based on the input of the outlet plate temperature profile, issues a command to the valve 30, and The cooling amount in the width direction of the nozzles 3a and 3b is controlled so that the sheet temperature profile becomes constant (of course, the sheet temperature of the strip X becomes the target outlet sheet temperature as a result of gas jet cooling by the nozzles 3a and 3b). In the same way, the overall cooling amount is adjusted).

Further, as for the roll cooling amount control by the control arithmetic unit 5, as shown in FIG. 2, the cooling amount of the cooling roll which comes into contact with the strip X earlier is larger than the cooling amount of the roll which comes later. Control.

As described above, in the configuration of the present embodiment, the predetermined amount of tension is applied to the strip X by the bridle rolls 2a and 2b, so that the floating amount of the strip edge portion in contact with each of the cooling rolls 1a to 1e can be suppressed. As a result, the flapping of the strip X is reduced, and the occurrence of scratches due to the contact between the gas jet nozzles 3a, 3b and the strip X is also eliminated. Therefore, the distance between the nozzles 3a, 3b and the strip X can be reduced. The edge portion can be efficiently cooled. In addition, H ₂ 4
0% to 90%, using N ₂ 10 to 60% of high heat transfer rate for the gas.

The gas jet nozzles 3a and 3b are
The cooling is positively performed on the high-temperature portion centered on the edge of the strip X measured in the above, so that uniform cooling can be expected.

Further, in the present embodiment, the cooling amount of the cooling rolls 1a to 1e is controlled so that the cooling amount of the later-ordered roll contacting the strip X is equal to or smaller than the cooling amount of the earlier-ordered roll. Therefore, the edge portion that is not cooled does not reach the central portion of the plate width, and the cooling load of the gas jet nozzle arranged on the cooling roll cluster side can be reduced.

FIG. 3 shows the sheet temperature profile in the width direction obtained by carrying out the present embodiment, and FIG. 4 shows the results of inspection of the aging index in the strip X width direction. As shown in these figures, the sheet temperature profile in the width direction on the exit side of the roll cooling device became uniform, and no shape collapse occurred. In addition, since a portion having an inferior aging index at the edge portion can be prevented from reaching the center portion of the sheet width, a product having a more uniform material can be manufactured.

Further, FIGS. 5 and 6 show an embodiment in which the apparatus configuration of the present invention is used in a vertical roll cooling apparatus of a continuous strip annealing facility, in which FIG. FIG. 6 shows a configuration in which the strip X enters from the upper side to the lower side, and FIG. 6 shows a configuration in which the strip X enters from the upper side to the lower side.

[0022]

According to the configuration of the strip cooling apparatus of the present invention as described above, it is possible to minimize the cooling unevenness in the width direction generated in the cooling roll group, and to reduce the cooling load of the gas jet nozzle. In addition, the equipment cost and the operating cost can be reduced, and the uniform material can be obtained in the width direction, and the strip shape does not collapse at the cooling roll group outlet in the operating surface, and stable production can be performed. Will be able to do it.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a roll cooling device configuration to which the configuration of the present invention is applied.

FIG. 2 is a graph showing a roll cooling amount in the present embodiment.

FIG. 3 is a graph showing a temperature distribution at a strip edge obtained by the configuration of the present embodiment.

FIG. 4 is a graph showing an aging index distribution at a strip edge obtained by the configuration of the present embodiment.

FIG. 5 is an explanatory view showing the configuration of another embodiment of the present invention.

FIG. 6 is an explanatory view showing the configuration of another embodiment of the present invention.

FIG. 7 is a perspective view showing a strip deformation model when a roll is wound;

FIG. 8 is an explanatory diagram of a floating portion generated at a strip edge portion when a roll is wound.

FIG. 9 is a graph showing a relationship between a lifting amount and a tension generated at a strip edge portion when a roll is wound.

FIG. 10 is a graph showing a temperature distribution at a strip edge obtained by a conventional configuration.

FIG. 11 is a graph showing an aging index distribution at a strip edge obtained by a conventional configuration.

FIG. 12 is a graph showing the temperature drop amount obtained when the conventional configuration is cooled and the temperature distribution at the strip edge.

FIG. 13 is a graph showing a temperature drop amount and a temperature distribution at a strip edge portion obtained when the cooling is performed by the configuration of the present invention.

FIG. 14 is an explanatory view showing a conventional roll cooling configuration.

[Explanation of symbols]

 1a ~ 1e Cooling roll 2a, 2b Bridle roll 3a, 3b Gas jet nozzle 4 Sheet thermometer 5 Control arithmetic unit X strip

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-274822 (JP, A) JP-A-3-207821 (JP, A) JP-A-60-125331 (JP, A) JP-A-61- 243128 (JP, A) JP-A-2-22424 (JP, A) JP-A-2-1222063 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C21D 9/52, 9 / 573

Claims (2)

(57) [Claims] 1. A bridle roll is disposed on each of an inlet side and an outlet side of a cooling roll group, and a gas jet nozzle capable of adjusting a cooling amount in a strip width direction is provided between the cooling roll group outlet side and an outlet bridle roll. A control arithmetic unit for installing a sheet thermometer capable of measuring the temperature profile in the strip width direction on the outlet bridle roll side and adjusting the cooling amount of the gas jet nozzle in the strip width direction based on the measured value of the sheet thermometer. A strip cooling device for continuous annealing, comprising: 2. The strip cooling apparatus for continuous annealing according to claim 1, wherein, among the cooling rolls, a roll having a lower order of contact with the strip has a smaller cooling amount than a roll having an earlier order. 2. The strip cooling apparatus for continuous annealing according to claim 1, wherein the cooling rate is equal.