JPH05209230A - Strip cooling device for continuous annealing - Google Patents

Abstract

PURPOSE:To stably manufacture a product, where the temperature profile in the direction of the strip width is improved and the quality is uniform by using a strip cooling device where cooling rolls are employed in a continuous annealing equipment. CONSTITUTION:Bridle rolls 2a, 2b are arranged on the entry side and the exit side of cooling rolls 1a to 1e, and gas-blowing nozzles 3a to 3e which perform blowing of the cooling gas toward the contact surface of the cooling rolls with a strip X are provided to the respective cooling rolls 1a to 1e, and, at the same time, gas jet nozzles 4a, 4b are provided between the cooling roll 1e and the bridle roll 2b, and a sheet temperature meter 5 which is capable of measuring the temperature profile in width direction of the strip X is provided on the bridle roll 2b side, and the measured value is inputted to a control and arithmetic device 6. This control and arithmetic device 6 provides a command to the gas jet nozzles 4a, 4b on the basis of input of the measured value so that the sheet temperature distribution in the width direction of the strip X may be uniform, performing the adjustment of the cooling in the width direction of these strips.

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. 12 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 cooled toward the contact surface between the cooling roll and the strip. A gas spray nozzle for spraying gas is provided for each cooling roll, and a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is provided between the cooling roll group outlet side and outlet side bridle roll. A plate thermometer capable of measuring a temperature profile in the strip width direction is installed on the side bridle roll side, and a control arithmetic unit for adjusting the cooling amount in the strip width direction of the gas jet nozzle based on the measurement value of the plate thermometer is provided. That is the basic feature.

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. 5, 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. 6, 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. 7, 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. 8 and the aging index is inferior at the edge portion as shown in FIG. Is manufactured,
As the strip shape collapsed, meandering and throttling occurred in the furnace, resulting in 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 changing from kgf / mm ² to 3kgf / mm ² , it is possible to reduce the edge lift amount to about half. In addition, it is not possible to expect complete cooling of the edge just by applying tension to the strip,
A gas spray nozzle for spraying a gas onto the contact surface between the cooling roll and the strip is installed for each cooling roll to cool the gap between the roll and the strip to eliminate cooling unevenness and to strip the cooling roll group to the subsequent stage. A gas jet nozzle with adjustable cooling amount in the width direction is arranged, and the strip width direction temperature profile is measured by a plate thermometer installed on the exit side bridle roll side, and the measurement signal is sent to the control arithmetic unit for edge cooling. By controlling the amount, a uniform temperature distribution can be obtained on the outlet side of the cooling device.

On the other hand, as shown in FIG. 10 (a), when the cooling amount of the rolls which come in contact with the strip later in the plurality of cooling rolls is made larger than the cooling amount of the rolls which come earlier in the sequence, The high temperature part of the edge as shown in b) extends to the central part of the plate width, and the cooling load at the gas jet nozzle installed on the exit side of the cooling roll group also increases,
In addition, the part with poor aging enters the center of the plate width. Therefore, in the present invention, as shown in FIG. 11 (b), the cooling amount of the roll that comes in contact with the strip as shown in FIG. 11 (a) earlier is made larger than the cooling amount of the roll that 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. Among these, in the present roll cooling device, a plate thermometer 50 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 6 described later, and in the control calculation device 6, The roll cooling amount is calculated from the inlet plate temperature, the target outlet plate temperature that has been input in advance, and the strip size and line speed. Based on this calculation, the control calculation device 6 gives a command to the roll wrap angle adjusters 10a to 10e of the cooling rolls 1a to 1e and the position adjustment devices 30a to 30e of the gas spray nozzles 3a to 3e described later, respectively. It is possible to adjust the amount of cooling of the roll and the position of the nozzle for blowing gas.

In this embodiment, bridle rolls 2a and 2b are provided on the inlet side and the outlet side of the cooling rolls 1a to 1e, respectively, and the cooling gas is sprayed toward the contact surface between the cooling roll and the strip X. The spray nozzles 3a to 3e are connected to the respective cooling rolls 1a.
1 to each 1e, provided with gas jet nozzles 4a, 4b between the cooling roll 1e (more precisely, the deflector roll 71) and the exit side bridle roll 2b, and on the exit side bridle roll 2b side, a multiple reflection thermometer and A strip thermometer 5 composed of a radiation thermometer capable of measuring a temperature profile in the strip width direction is installed, and the exit strip temperature profile is input to a control arithmetic unit 6. In this control arithmetic unit 6, in addition to adjusting the position of the gas blowing nozzle and adjusting the roll cooling amount as described above, the cooling amount in the width direction of the gas jet nozzles 4a, 4b is determined by inputting the outlet plate temperature profile. , A command is issued to the valve 40 to control the widthwise cooling amount of the nozzles 4a, 4b so that the outlet plate temperature profile becomes constant (as a result of the gas jet cooling by the nozzles 4a, 4b, the strip X The total cooling amount is also adjusted so that the plate temperature reaches the target outlet plate temperature).

Further, regarding the roll cooling amount control by the control arithmetic unit 6, 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 to suppress the floating amount 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 occurrence of scratches due to the contact between the post-stage gas jet nozzles 4a and 4b and the strip X. Therefore, the distance between the nozzles 4a and 4b and the strip X can be shortened. Therefore, the edge portion can be cooled efficiently. In addition, H is used as the spray gas.
₂ 40% to 90%, using N ₂ 10 to 60% of high heat transfer rate for the gas.

Further, the gas spray nozzles 3a to 3e are arranged for each of the cooling rolls 1a to 1e, and the cooling gas is sprayed between the contact surfaces of the strip X and the cooling rolls. The temperature unevenness at 1e to 1e can be suppressed to a small one, so the gas jet nozzle installed in the latter stage
The cooling load on 4a and 4b can be reduced.

Further, the latter-stage gas jet nozzles 4a, 4b positively cool the high temperature portion centered on the edge of the strip X measured by the plate thermometer 5, so that 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. Gas jet nozzle 4 arranged on the cooling roll group side
The cooling load of a and 4b can be further 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.

[0022]

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

FIG. 6 is an explanatory diagram of a floating portion that occurs at a strip edge portion when winding a roll.

FIG. 7 is a graph showing the relationship between the amount of floating and the tension that occurs at the strip edge portion when winding a roll.

FIG. 8 is a graph showing a temperature distribution at a strip edge portion obtained by the conventional configuration.

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

FIG. 10 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. 11 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. 12 is an explanatory diagram showing a conventional roll cooling configuration.

[Explanation of symbols]

 1a to 1e Cooling rolls 2a and 2b Bridle rolls 3a to 3e Gas spray nozzles 4a and 4b Gas jet nozzles 5 Plate thermometer 6 Control computing device X strip

Claims (2)

[Claims] 1. A bridle roll is provided on each of an inlet side and an outlet side of a cooling roll group, and a gas spray nozzle for spraying a cooling gas toward a contact surface between the cooling roll and the strip is provided for each cooling roll. At the same time, a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is provided between the cooling roll group outlet side and the outlet side bridle roll, and a plate temperature capable of measuring the temperature profile in the strip width direction on the outlet side bridle roll side. A strip cooling device for continuous annealing, which is provided with a controller and which is provided with a control arithmetic device for adjusting the cooling amount in the strip width direction of the 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.