JPH05209229A - Strip cooling device for continuous annealing - Google Patents

Abstract

PURPOSE:To improve a temp. profile in the width direction of a strip and to stably manufacture a product having uniform quantity, in a strip cooling device using cooling rolls in a continuous annealing device. CONSTITUTION:Bridle rolls 2a, 2b are arranged at the inlet side and the outlet side of the cooling rolls 1a-1e, respectively, and rear surface gas jet nozzles 3a-3e for executing the rear surface cooling to the strip X being in contact with the cooling rolls are arranged at each cooling roll 1a-1e and also, rear step gas jet nozzles 3f, 3g are provided between the cooling roll 1e and the bridle roll 2b. On the other hand, a strip thermometer 4 for measuring the temp. profile in the width direction of the strip X is disposed at the bridle roll 2b side and the measured values are inputted to a control arithmetic unit 5. The control arithmetic unit 5 issues the command to the gas jet nozzles 3a-3g so that the strip temp. distribution in the width direction of the strip X is uniform by inputting the measured values to execute the adjustment of cooling quantity in the width direction 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 cooling device for quenching strips by cooling rolls for continuous annealing.

[0002]

2. Description of the Related Art In a strip roll cooling method carried out in a continuous annealing equipment, a cooling roll having a spiral groove inside and a coolant such as cooling water passing through the groove is usually used. ..

FIG. 13 shows an example of the structure of a quenching equipment for continuous annealing of 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 the direction orthogonal to the strip pass line, and the contact area with the strip X is changed by these movements to obtain a predetermined temperature drop amount. You can do it.

[0004]

However, in the above-described roll cooling equipment, uneven cooling is apt to occur such that the temperature of the strip edge portion becomes high, and the temperature distribution in the strip width direction is non-uniform. When the temperature distribution in the plate width direction becomes non-uniform, the shape of the strip X is deformed, and meandering or throttling occurs in the subsequent overaging furnace, which significantly impairs the stable operation of the furnace. .. In addition, when such a non-uniform temperature distribution occurs, the important aging index among the materials of general cold-rolled steel sheet is partially inferior at the edge portion, etc., and there is a problem that only products with uneven material in the width direction can be manufactured. Was there.

The present invention was devised in view of the above problems of the prior art. In a cooling device for performing roll cooling for continuous strip annealing, the temperature profile in the strip width direction is improved and a uniform temperature profile is obtained. The purpose is to obtain a stable product of the material.

[0006]

Therefore, in the strip annealing apparatus for continuous annealing of the present invention, bridle rolls are arranged on the inlet side and the outlet side of the cooling roll group, respectively, and the back face for cooling the strip that comes into contact with the cooling roll is back faced. A gas jet nozzle is provided for each cooling roll, and a downstream gas jet nozzle capable of adjusting the cooling amount in the strip width direction is provided between the cooling roll group exit side and the exit side bridle roll, and further on the exit side bridle roll side. A plate thermometer capable of measuring the temperature profile in the strip width direction is installed, and a control calculation for adjusting the cooling amount in the strip width direction of the back side gas jet nozzle and / or the rear gas jet nozzle based on the measured value of the plate thermometer The basic feature is that it has a device.

The above-mentioned structure is made based on the clarification of the cause of the problem in the prior art by the present inventors. The clarified cause will be described in detail below.

It is estimated that the occurrence of cooling unevenness in the conventional structure is caused mainly by the low contact surface pressure between the cooling roll and the strip. In particular, as shown in FIG. 6, by winding the strip X around a cooling roll to give a curvature R, the roll contact side of the strip X receives a tensile stress in the roll axial direction and the opposite side receives a compressive stress. As a result, as shown in FIG. 7, a portion H that does not completely contact the cooling roll 1 is generated at the edge portion of the strip X. As shown in FIG. 8, the edge lift amount H tends to increase when the strip tension of the cooling roll portion is small. Due to the above phenomenon, the strip edge portion has a high temperature distribution as shown in FIG. 9, and the aging index is inferior at the edge portion as shown in FIG. Was produced, and the meandering and throttling in the furnace due to the collapse of the strip shape occurred, resulting in the inability to operate stably.

The above-mentioned problem is to install a tension applying device such as a bridle roll which can apply a tension to the strip before and after the cooling roll group (for example, by this, the strip tension is 1
by the kgf / mm ² to 3kgf / mm ^2), it can reduce the edge flying height to about half. In addition, since it is not possible to expect complete cooling of the edge just by applying tension to the strip, a post-stage gas jet nozzle that can adjust the cooling amount in the strip width direction is placed on the cooling roll grouping side, and the roll is in contact with the roll. A backside gas jet nozzle that cools the backside of the strip is placed on each of the cooling rolls, and the temperature is measured by a plate thermometer that measures the widthwise temperature profile installed on the exit bridle roll side. By sending a signal to the control arithmetic unit to control the cooling amount of the rear gas jet nozzle and / or the back gas jet nozzle in the strip width direction, it becomes possible to obtain a uniform temperature distribution on the outlet side of the cooling device.

On the other hand, as shown in FIG. 11 (a), when the cooling amount of the roll that comes in contact with the strip later in the plurality of cooling rolls is made larger than that of the roll that comes earlier in the sequence, The high temperature part of the edge as shown in b) extends to the center of the plate width, and the cooling load at the rear gas jet nozzle and the rear gas jet nozzle installed on the exit side of the cooling roll group also becomes large, and the aging effect is high. The inferior part will enter the center of the plate width. Therefore, in the present invention, as shown in FIG. 12 (a), the cooling amount of the roll which comes first in contact with the strip as shown in FIG. 12 (a) is made larger than the cooling amount of the roll which comes later in the sequence. The high temperature part of the edge can be prevented from reaching the center of the plate width.

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

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing a horizontal roll cooling device in a strip continuous annealing equipment in a state in which the structure of one embodiment of the present invention is applied.

The strip X, which has been heated and soaked and then gradually cooled, enters the roll cooling device to cool the rolls 1a to 1a.
It will be cooled in 1e and sent to the next overaging treatment. Of 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, and the measured value is input to the control calculation device 5 described later, and in the control calculation device 5, The roll cooling amount is calculated from the inlet plate temperature, the target outlet plate temperature that has been 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 the roll wrap angle adjusters 10a to 10e of the cooling rolls 1a to 1e, respectively, so that the cooling amount of each roll can be adjusted (the present embodiment In the example, the control arithmetic unit 5 includes a rear gas jet nozzle 3a described later.
To 3e position adjusting devices 36a to 36e, respectively, commands are issued,
These nozzles 3a to 3e are prevented from coming into contact with the strip X).

In the present embodiment, the bridle rolls 2a and 2b are arranged on the inlet side and the outlet side of the cooling rolls 1a to 1e, respectively, and the curved rear gas jet for cooling the rear face of the strip X in contact with the cooling rolls. Nozzles 3a to 3e are provided for each of the cooling rolls 1a to 1e, and post-stage gas jet nozzles 3f and 3g are provided between the cooling roll 1e (correctly, the deflector roll 61) and the exit side bridle roll 2b. Further, on the exit side bridle roll 2b side, a strip thermometer 4 consisting of a multiple reflection thermometer and a radiation thermometer capable of measuring the temperature profile in the strip width direction is installed, and the exit strip temperature profile is input to the control arithmetic unit 5. There is. In this control calculation device 5, in addition to adjusting the roll cooling amount as described above, the cooling amount in the width direction of the rear gas jet nozzles 3a to 3e and the rear gas jet nozzles 3f and 3g is determined by inputting the outlet plate temperature profile. , The valves 30 to 35 are commanded to control the widthwise cooling amount of these nozzles 3a to 3g so that the outlet plate temperature profile becomes constant (of course, these nozzles 3a to 3g
As a result of the gas jet cooling by, the total cooling amount is adjusted so that the strip X plate temperature becomes the target outlet plate temperature).

Regarding the roll cooling amount control by the control arithmetic unit 5, as shown in FIG. 2, the cooling amount of the cooling roll having the earliest contact with the strip X becomes larger than the cooling amount of the roll having the slower order. Are controlled.

As described above, in the structure of this embodiment, the bridle rolls 2a and 2b apply a predetermined tension to the strip X, thereby suppressing the amount of floating of the strip edge portion in contact with the cooling rolls 1a to 1e. This also reduces the fluttering of the strip X and eliminates the generation of scratches due to the contact between the latter stage gas jet nozzles 3f and 3g and the strip X, so that the nozzles 3f and 3g can be eliminated.
The distance between the strip and the strip X can be shortened, and the edge portion can be efficiently cooled. As the blowing gas, a gas having a high heat transfer coefficient of H ₂ 40 to 90% and N ₂ 10 to 60% is used.

Further, since the back side gas jet nozzles 3a to 3e provided on the back side of the strip X in contact with the cooling rolls 1a to 1e cool the high temperature portion on the edge side of the strip X as a center. , These cooling rolls
The temperature unevenness in 1a to 1e can be suppressed small, and the cooling load of the rear gas jet nozzles 3f and 3g installed in the rear can be reduced.

Further, since the gas jet nozzles 3a to 3g positively cool the high temperature portion centered on the edge of the strip X measured by the plate thermometer 4, uniform cooling can be expected.

In addition, in this embodiment, the cooling rolls 1a to 1e
In order to control the cooling amount of the strip X, the cooling amount of the roll that comes in contact with the strip X later is made equal to or smaller than the cooling amount of the roll that comes earlier in the sequence. The rear gas jet nozzle 3a of each cooling roll 1a to 1e
3 to 3e and the cooling gas loads on the downstream gas jet nozzles 3f and 3g arranged on the cooling roll feeding side can be reduced.

FIG. 3 shows the widthwise plate temperature profile obtained by carrying out this embodiment, and FIG. 4 shows the results of the aging index test in the strip X widthwise direction. As shown in these figures, the widthwise plate temperature profile on the outlet side of the roll cooling device was uniform, and the shape collapse did not occur. Further, since it is possible to prevent the portion of the edge portion having a poor aging index from reaching the central portion of the plate width, it is possible to manufacture a product having a more uniform material.

Further, FIG. 5 shows the configuration of another embodiment in which the apparatus configuration of the present invention is used in the horizontal roll cooling apparatus of strip continuous annealing equipment.

[0023]

According to the structure of the strip cooling device of the present invention as described above, it is possible to prevent the uneven cooling in the width direction generated in the cooling roll group from being suppressed to a minimum and to reduce the cooling load of the gas jet nozzle. In addition to being able to reduce the equipment cost and operating cost, a uniform material can be obtained in the width direction, and also in the operating side, the strip shape does not collapse at the exit of the cooling roll group, and stable production is performed. Will be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an 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 of a strip edge portion obtained by the configuration of this embodiment.

FIG. 4 is a graph showing the aging index distribution of the strip edge portion obtained in the configuration of this embodiment.

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

FIG. 6 is a perspective view showing a strip deformation model at the time of winding a roll.

FIG. 7 is an explanatory diagram of a floating portion that occurs at a strip edge portion when winding a roll.

FIG. 8 is a graph showing the relationship between the amount of lift and the tension that occurs at the strip edge portion when winding a roll.

FIG. 9 is a graph showing a temperature distribution of a strip edge portion obtained by the conventional configuration.

FIG. 10 is a graph showing the aging index distribution of the strip edge portion obtained by the conventional configuration.

FIG. 11 is a graph showing a temperature drop amount and a temperature distribution of a strip edge portion obtained when cooled by a conventional configuration.

FIG. 12 is a graph showing a temperature drop amount and a temperature distribution of a strip edge portion obtained when cooled according to the configuration of the present invention.

FIG. 13 is an explanatory diagram showing a conventional roll cooling configuration.

[Explanation of symbols]

 1a to 1e Cooling rolls 2a, 2b Bridle rolls 3a, 3b, 3c, 3d, 3e Rear gas jet nozzles 3f, 3g Rear gas jet nozzles 4 Plate thermometer 5 Control processor X strip

Claims (2)

[Claims] 1. A bridle roll is provided on each of the inlet side and the outlet side of the cooling roll group, and a backside gas jet nozzle for cooling the backside of the strip in contact with the cooling roll is provided for each cooling roll group. Between the outlet side and the outlet side bridle roll, a downstream gas jet nozzle that can adjust the cooling amount in the strip width direction is installed, and a strip thermometer that can measure the temperature profile in the strip width direction is installed on the outlet side bridle roll side. A strip cooling device for continuous annealing, further comprising a control arithmetic device for adjusting the strip width direction cooling amount of the backside gas jet nozzle and / or the post-stage gas jet nozzle based on the measured value of the plate thermometer. 2. The continuous annealing strip cooling device according to claim 1, wherein among the cooling roll groups, the rolls that come in contact with the strip later have a smaller cooling amount than the rolls that have earlier turn, or The strip cooling device for continuous annealing according to claim 1, wherein the strip cooling devices are equal.