JPH05202430A - Device for cooling strip for continuous annealing - Google Patents

Abstract

PURPOSE:To improve a temp. profile in the width direction of a strip and to stably manufacture the product having uniform material in a device for cooling the strip using cooling rolls in continuous annealing equipment. CONSTITUTION:At an inlet side and an outlet side of the cooling rolls 1a-1e, bridle rolls 2a, 2b are arranged respectively and gas jet nozzles 3a and 3b, and 3c and 3d are arranged between the inlet side bridle roll 2a and the cooling roll 1a, and between the cooling roll 1e and the outlet side bridle roll 2b respectively and also, a strip thermometer 4 enabling measurement of the temp. profile in the width direction of the strip X is arranged at the bridle roll 2b side and these measured values are inputted to a control arithmetic device 5. This control arithmetic device 5 outputs a command to the gas jet nozzles 3a, 3b, 3c, 3d so that the strip temp. distribution in the width direction of the strip X uniformizes by inputting the measured values and the adjustment of the cooling rate in the width direction of the strip is executed.

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 cooling device 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 inlet side bridle roll and the cooling roll group inlet side are provided. Between them and between the cooling roll group outlet side and outlet side bridle roll, a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is provided, and the temperature profile in the strip width direction can be measured on the outlet side bridle roll side. A basic feature is that a plate thermometer is installed, and further a control arithmetic unit is provided for adjusting the cooling amount in the strip width direction of the gas jet nozzle based on the measured value of the plate thermometer.

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 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 k
by from gf / mm ² to 3kgf / mm ^2), it can reduce the amount Ri edge flying about half. Further, it is not possible to expect complete cooling of the edge only by applying tension to the strip, and gas jet nozzles with adjustable cooling amounts in the strip width direction are arranged on the inlet side and outlet side of the cooling roll group, and the outlet side bridle is used. The temperature is measured by a plate thermometer that measures the temperature profile in the width direction on the roll side, and the measured signal is sent to a control arithmetic unit to control the cooling amount in the width direction of the strip, thereby achieving a uniform temperature distribution. It can be obtained at 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, the cooling load at the gas jet nozzles installed on the inlet side and the outlet side of the cooling roll group becomes large, and the portion with poor aging property Will enter the center of the board 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. 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 calculation device 5 can give a command to the roll wrap angle adjusters 10a to 10e of the cooling rolls 1a to 1e, respectively, to adjust the cooling amount of each roll.

In this 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 between the inlet side bridle roll 2a and the cooling roll 1a (correctly, the deflector roll 60). And 61) and chill roll 1e
Gas jet nozzles 3a and 3b, 3c and
3d is provided, and on the exit side bridle roll 2b side, a strip thermometer 4 composed of a multiple reflection thermometer and a radiation thermometer capable of measuring the temperature profile in the strip width direction is installed, and further, the outlet strip temperature profile is controlled and operated by a computing device. You are typing in 5. 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 gas jet nozzles 3a and 3b, 3c and 3d is determined by inputting the outlet plate temperature profile, and the valve 30 and The nozzles 3a and 3b and the width direction cooling amounts of the nozzles 3a and 3b are controlled so that the outlet plate temperature profile becomes constant by issuing a command to 31 (of course, the nozzles 3a and 3b,
As a result of the gas jet cooling by 3c and 3d, the total cooling amount is also adjusted so that the plate temperature of the strip X 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. By doing so, the fluttering of the strip X is reduced, and the scratches caused by the contact between the gas jet nozzles 3a, 3b, 3c, 3d and the strip X are also eliminated.
The distance between b, 3c, 3d and the strip X can be shortened, and the edge portion can be cooled efficiently. 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.

The gas jet nozzles 3a, 3b, 3c, 3d are
Since the high temperature portion centered on the edge of the strip X measured by the plate thermometer 4 is actively cooled, uniform cooling can be expected.

Further, in the present embodiment, in controlling the cooling amount of the cooling rolls 1a to 1e, the cooling amount of the roll that comes later in contact with the strip X is made equal to or smaller than the cooling amount of the roll that comes earlier in the sequence. 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 nozzles arranged on the inlet side and the outlet side of the cooling roll group can be small.

FIG. 3 shows the widthwise plate temperature profile obtained by carrying out the present embodiment, and FIG. 4 shows the results of inspection of the aging index 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.

[0021]

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, 2b Bridle rolls 3a, 3b, 3c, 3d Gas jet nozzles 4 Plate thermometers 5 Control calculator X strip

Claims (2)

[Claims] 1. Bridle rolls are respectively arranged on the inlet side and the outlet side of the cooling roll group, and between the inlet side bridle roll and the cooling roll group inlet side and between the cooling roll group outlet side and the outlet side bridle roll. , Each equipped with a gas jet nozzle capable of adjusting the cooling amount in the strip width direction, and a strip thermometer capable of measuring the strip profile in the strip width direction on the exit side bridle roll side. A strip cooling device for continuous annealing, comprising a control arithmetic device for adjusting the strip width direction cooling amount of the gas jet nozzle based on the control computing device. 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.